taurochenodeoxycholic-acid and ursodoxicoltaurine

Bile acids, which are synthesized in liver and colon, facilitate the digestion of dietary lipids. In addition to this metabolic function, they also act as molecular signals with activities in the nervous system. These are mediated primarily by a G-protein-coupled bile acid receptor (known as TGR5). Preceded by a long tradition in Chinese medicine, bile acids are now being investigated as therapeutic options in several neuropathologies. Specifically, one bile acid, tauroursodeoxycholic acid (TUDCA), which passes the blood-brain barrier and shows anti-inflammatory and anti-apoptotic effects, has been tested in animal models of spinal cord injury (SCI). In this review, we discuss the evidence for a therapeutic benefit in these preclinical experiments. At the time of writing, 12 studies with TGR5 agonists have been published that report functional outcomes with rodent models of SCI. Most investigations found cytoprotective effects and benefits regarding the recovery of sensorimotor function in the subacute phase. When TUDCA was applied in a hydrogel into the lesion site, a significant improvement was obtained at 2 weeks after SCI. However, no lasting improvements with TUDCA treatment were found, when animals were assessed in later, chronic stages. A combination of TUDCA with stem cell injection failed to improve the effect of the cellular treatment. We conclude that the evidence does not support the use of TUDCA as a treatment of SCI. Nevertheless, cytoprotective effects suggest that different modes of application or combinatorial therapies might still be explored.

Topics: Animals; Models, Animal; Receptors, G-Protein-Coupled; Spinal Cord Injuries; Taurochenodeoxycholic Acid

Adipose tissue is an organ with metabolic and endocrine activity. White, brown and ectopic adipose tissues have different structure, location, and function. Adipose tissue regulates energy homeostasis, providing energy in nutrient-deficient conditions and storing it in high-supply conditions. To attend to the high demand for energy storage during obesity, the adipose tissue undergoes morphological, functional and molecular changes. Endoplasmic reticulum (ER) stress has been evidenced as a molecular hallmark of metabolic disorders. In this sense, the ER stress inhibitor tauroursodeoxycholic acid (TUDCA), a bile acid conjugated to taurine with chemical chaperone activity, has emerged as a therapeutic strategy to minimize adipose tissue dysfunction and metabolic alterations associated with obesity. In this review, we highlight the effects of TUDCA and receptors TGR5 and FXR on adipose tissue in the setting of obesity. TUDCA has been demonstrated to limit metabolic disturbs associated to obesity by inhibiting ER stress, inflammation, and apoptosis in adipocytes. The beneficial effect of TUDCA on perivascular adipose tissue (PVAT) function and adiponectin release may be related to cardiovascular protection in obesity, although more studies are needed to clarify the mechanisms. Therefore, TUDCA has emerged as a potential therapeutic strategy for obesity and comorbidities.

Topics: Adipose Tissue; Adiposity; Humans; Obesity; Taurochenodeoxycholic Acid

Phase II studies on tauro-urso-deoxycholic acid (TUDCA) raised the promise of safety and efficacy in patients with amyotrophic lateral sclerosis, a currently incurable and devastating disease. We review the available evidence on the efficacy and safety of TUDCA, administered alone or in combination, by analyzing and comparing published and ongoing studies on amyotrophic lateral sclerosis. Two independent phase II studies (using TUDCA solo or combined with sodium phenylbutyrate) showed similar efficacy in slowing disease progression measured by functional scales. One open-label follow-up TUDCA+sodium phenylbutyrate study suggested a benefit on survival. Two subsequent phase III studies with TUDCA (solo or combined with sodium phenylbutyrate) have been initiated and are currently ongoing. Their completion is expected by the end of 2023 and beginning of 2024. Evidence collected by phase II studies indicates that there are no safety concerns in patients with amyotrophic lateral sclerosis. The efficacy shown in phase II studies was considered sufficient to grant approval in some countries but not in others, owing to discrepant views on the strength of evidence. It will be necessary to wait for the results of ongoing phase III studies to attain a full appreciation of these data.

Topics: Amyotrophic Lateral Sclerosis; Humans; Phenylbutyrates; Taurochenodeoxycholic Acid

Most neurodegenerative disorders are diseases of protein homeostasis, with misfolded aggregates accumulating. The neurodegenerative process is mediated by numerous metabolic pathways, most of which lead to apoptosis. In recent years, hydrophilic bile acids, particularly tauroursodeoxycholic acid (TUDCA), have shown important anti-apoptotic and neuroprotective activities, with numerous experimental and clinical evidence suggesting their possible therapeutic use as disease-modifiers in neurodegenerative diseases. Experimental evidence on the mechanisms underlying TUDCA's neuroprotective action derives from animal models of Alzheimer's disease, Parkinson's disease, Huntington's diseases, amyotrophic lateral sclerosis (ALS) and cerebral ischemia. Preclinical studies indicate that TUDCA exerts its effects not only by regulating and inhibiting the apoptotic cascade, but also by reducing oxidative stress, protecting the mitochondria, producing an anti-neuroinflammatory action, and acting as a chemical chaperone to maintain the stability and correct folding of proteins. Furthermore, data from phase II clinical trials have shown TUDCA to be safe and a potential disease-modifier in ALS. ALS is the first neurodegenerative disease being treated with hydrophilic bile acids. While further clinical evidence is being accumulated for the other diseases, TUDCA stands as a promising treatment for neurodegenerative diseases.

Topics: Amyotrophic Lateral Sclerosis; Animals; Bile Acids and Salts; Neurodegenerative Diseases; Taurochenodeoxycholic Acid

Topics: Adult; Amyotrophic Lateral Sclerosis; Humans; Pharmaceutical Preparations; Phenylbutyrates; Taurochenodeoxycholic Acid

Bile acids have received increasing attention over the past years as their multiple alternative roles became clearer. Tauroursodeoxycholic Acid (TUDCA) in specific has generated special interest due to its ability to promote pancreatic survival and function, as well as reduce endoplasmic reticulum stress. However, there are few studies explaining the molecular mechanisms behind TUDCA's beneficial actions on pancreatic beta cells. In this review, we decided to review the literature in order to craft a primer for researchers on what is known about TUDCA's receptors and the molecular pathways involved in this bile acid's function in the endocrine pancreas. We review the studies that focused on G protein-coupled bile acid receptor (TGR5), Sphingosine-1-phosphate receptor 2 (S1PR2) and α5β1 Integrin function in pancreatic cells. Our hope is to provide a basis for future studies to expand upon, especially considering the current lack of studies focusing on the importance of these receptors, either through TUDCA signaling or other signaling molecules.

Topics: Insulin-Secreting Cells; Receptors, G-Protein-Coupled; Signal Transduction; Taurochenodeoxycholic Acid

Bear bile has been used in Traditional Chinese Medicine for thousands of years due to its therapeutic potential and clinical applications. The tauroursodeoxycholic acid (TUDCA), one of the acids found in bear bile, is a hydrophilic bile acid and naturally produced in the liver by conjugation of taurine to ursodeoxycholic acid (UDCA). Several studies have shown that TUDCA has neuroprotective action in several models of neurodegenerative disorders (ND), including Alzheimer's disease, Parkinson's disease, and Huntington's disease, based on its potent ability to inhibit apoptosis, attenuate oxidative stress, and reduce endoplasmic reticulum stress in different experimental models of these illnesses. Our research extends the knowledge of the bile acid TUDCA actions in ND and the mechanisms and pathways involved in its cytoprotective effects on the brain, providing a novel perspective and opportunities for treatment of these diseases.

Topics: Alzheimer Disease; Animals; Apoptosis; Bile; Bile Acids and Salts; Endoplasmic Reticulum Stress; Humans; Medicine, Chinese Traditional; Neurodegenerative Diseases; Taurochenodeoxycholic Acid; Ursodeoxycholic Acid

Bile acids are produced in the liver and excreted into the intestine, where their main function is to participate in lipid digestion. Ursodeoxycholic acid (UDCA) and tauroursodeoxycholic acid (TUDCA) have shown antiapoptotic, anti-inflammatory, and antioxidant effects in various models of neurodegenerative diseases. However, little is known about signaling pathways and molecular mechanisms through which these bile acids act as neuroprotectors, delaying translation to the clinical setting. We review evidence supporting a potentially therapeutic role for bile acids in retinal disorders, and the mechanisms and pathways involved in the cytoprotective effects of bile acids from the liver and the enterohepatic circulation to the central nervous system and the retina. As secondary bile acids are generated by the microbiota metabolism, bile acids might be a link between neurodegenerative retinal diseases and microbiota.

Topics: Animals; Cytoprotection; Humans; Nerve Degeneration; Neuroprotective Agents; Retinal Diseases; Taurochenodeoxycholic Acid; Ursodeoxycholic Acid

Tauroursodeoxycholic acid (TUDCA) is a naturally occurring hydrophilic bile acid that has been used for centuries in Chinese medicine. Chemically, TUDCA is a taurine conjugate of ursodeoxycholic acid (UDCA), which in contemporary pharmacology is approved by Food and Drug Administration (FDA) for treatment of primary biliary cholangitis. Interestingly, numerous recent studies demonstrate that mechanisms of TUDCA functioning extend beyond hepatobiliary disorders. Thus, TUDCA has been demonstrated to display potential therapeutic benefits in various models of many diseases such as diabetes, obesity, and neurodegenerative diseases, mostly due to its cytoprotective effect. The mechanisms underlying this cytoprotective activity have been mainly attributed to alleviation of endoplasmic reticulum (ER) stress and stabilization of the unfolded protein response (UPR), which contributed to naming TUDCA as a chemical chaperone. Apart from that, TUDCA has also been found to reduce oxidative stress, suppress apoptosis, and decrease inflammation in many in-vitro and in-vivo models of various diseases. The latest research suggests that TUDCA can also play a role as an epigenetic modulator and act as therapeutic agent in certain types of cancer. Nevertheless, despite the massive amount of evidence demonstrating positive effects of TUDCA in pre-clinical studies, there are certain limitations restraining its wide use in patients. Here, molecular and cellular modes of action of TUDCA are described and therapeutic opportunities and limitations of this bile acid are discussed.

Topics: Animals; Bile Acids and Salts; Diabetes Mellitus; Endoplasmic Reticulum Stress; Humans; Liver Diseases; Neoplasms; Neurodegenerative Diseases; Obesity; Taurochenodeoxycholic Acid

Bile acids (BAs) are key molecules in generating bile flow, which is an essential function of the liver. In the last decades, there have been great advances in the understanding of BA physiology, and new insights have emerged regarding the role of BAs in determining cell damage and death in several liver diseases. This new knowledge has helped to better delineate the pathophysiology of cholestasis and the adaptive responses of hepatocytes to cholestatic liver injury as well as of the mechanisms of injury of biliary epithelia. In this context, therapeutic approaches for liver diseases using hydrophilic BA (i.e., ursodeoxycholic acid, tauroursodeoxycholic, and, more recently, norursodeoxycholic acid), have been revamped. In the present review, we summarize current experimental and clinical data regarding these BAs and its role in the treatment of certain liver diseases.

Topics: Bile Acids and Salts; Cholestasis; Humans; Liver; Liver Diseases; Taurochenodeoxycholic Acid; Ursodeoxycholic Acid

Diseases that affect the eye, including photoreceptor degeneration, diabetic retinopathy, and glaucoma, affect 11.8 million people in the US, resulting in vision loss and blindness. Loss of sight affects patient quality of life and puts an economic burden both on individuals and the greater healthcare system. Despite the urgent need for treatments, few effective options currently exist in the clinic. Here, we review research on promising neuroprotective strategies that promote neuronal survival with the potential to protect against vision loss and retinal cell death. Due to the large number of neuroprotective strategies, we restricted our review to approaches that we had direct experience with in the laboratory. We focus on drugs that target survival pathways, including bile acids like UDCA and TUDCA, steroid hormones like progesterone, therapies that target retinal dopamine, and neurotrophic factors. In addition, we review rehabilitative methods that increase endogenous repair mechanisms, including exercise and electrical stimulation therapies. For each approach, we provide background on the neuroprotective strategy, including history of use in other diseases; describe potential mechanisms of action; review the body of research performed in the retina thus far, both in animals and in humans; and discuss considerations when translating each treatment to the clinic and to the retina, including which therapies show the most promise for each retinal disease. Despite the high incidence of retinal diseases and the complexity of mechanisms involved, several promising neuroprotective treatments provide hope to prevent blindness. We discuss attractive candidates here with the goal of furthering retinal research in critical areas to rapidly translate neuroprotective strategies into the clinic.

Topics: Animals; Cell Death; Electric Stimulation Therapy; Exercise Therapy; Humans; Nerve Growth Factors; Neurons; Neuroprotective Agents; Retina; Retinal Diseases; Taurochenodeoxycholic Acid; Ursodeoxycholic Acid; Vision Disorders

Nonalcoholic fatty liver disease (NAFLD) is a hepatic manifestation of metabolic syndrome. The prevalence of NAFLD in Japan has nearly doubled in the last 10-15 years. Increasing evidence supports undernourishment in utero being causatively connected with the risk of NAFLD in later life. Low body mass index (BMI) has been common among Japanese women of childbearing age for several decades due to their strong desire to be thin. It is plausible that insufficient maternal energy intake by pregnant Japanese women may underlie the rapid increase in the prevalence of NAFLD in Japan. In order to clarify the mechanisms by which undernourishment in utero primes adult hepatic steatosis, we developed a mouse model of fetal undernourishment with a hepatic fat deposit-prone phenotype on an obesogenic high fat diet in later life. We found that endoplasmic reticulum (ER) stress response parameters were activated concomitantly with the deterioration of hepatic steatosis and also that the alleviation of ER stress with the chemical chaperone, tauroursodeoxycholic acid (TUDCA), significantly improved hepatic steatosis. Therefore, undernourishment in utero may program the future integration of ER stress in the liver on an obesogenic diet in later life and also induce the deterioration of hepatic steatosis. These results also provide an insight into interventions for the potential high-risk population of NAFLD, such as those born small or exposed to maternal undernourishment during the fetal period, with the alleviation of ER stress by dietary supplements and/or specific food including chaperones.

Topics: Adult; Animals; Body Mass Index; Diet, High-Fat; Disease Models, Animal; Embryo, Mammalian; Endoplasmic Reticulum Stress; Energy Intake; Female; Fetus; Humans; Japan; Liver; Malnutrition; Mice; Non-alcoholic Fatty Liver Disease; Pregnancy; Prenatal Exposure Delayed Effects; Taurochenodeoxycholic Acid

Ursodeoxycholate and its taurine conjugate tauroursodeoxycholate (TUDC) promote choleresis by triggering the insertion of transport proteins for bile acids into the canalicular and basolateral membranes of hepatocytes. In addition, TUDC exerts hepatoprotective and anti-apoptotic effects, can counteract the action of toxic bile acids and reduce endoplasmic reticulum stress. TUDC can also initiate the differentiation of multipotent mesenchymal stem cells (MSC) including hepatic stellate cells and promote their development into hepatocyte-like cells. Although the hepatoprotective and choleretic action of TUDC is empirically used in clinical medicine since decades, the underlying molecular mechanisms remained largely unclear. Since TUDC has little or no potency to activate known bile acid receptors, such as farnesoid X receptor and transmembrane G protein-coupled bile acid receptor, other receptors must be involved in TUDC-mediated signaling. Recent research demonstrates that integrins serve as sensors for TUDC. After binding of TUDC to α5β1-integrin, the β1-integrin subunit becomes activated through a conformational change, thereby triggering integrin signaling with the downstream activation of focal adhesion kinase, c-Src, the epidermal growth factor receptor and activation of the mitogen-activated protein kinases, Erks and p38. These events trigger choleresis through a coordinated insertion of the sodium-taurocholate cotransporting polypeptide into the basolateral membrane and of the bile salt export pump into the canalicular membrane. In addition to its choleretic action, TUDC-induced integrin activation triggers a cyclic adenosine monophosphate-dependent protein kinase A activation in hepatocytes, which provides the basis for the anti-apoptotic effect of TUDC. On the other hand, the TUDC-induced stimulation of MSC differentiation appears not to be mediated by integrins. This article gives a brief overview about our work on the signaling network-mediating hepatoprotection by TUDC.

Topics: Animals; Apoptosis; Cell Differentiation; Humans; Integrins; Liver; Protective Agents; Taurochenodeoxycholic Acid

The objective of this review was to evaluate the potential of tauroursodeoxycholic acid (TUDCA) for neuroprotection in traumatic brain injury (TBI) patients in the neurocritical care setting. Specifically, we surveyed preclinical studies describing the neuroprotective and systemic effects of TUDCA, and the potential therapeutic application of TUDCA. Preclinical studies have provided promising data supporting its use in neurological disease characterized by apoptosis-induced neuronal loss. TUDCA inhibits multiple proteins involved in apoptosis and upregulates cell survival pathways. In addition, TUDCA exhibits anti-inflammatory effects in models of neuroinflammation and attenuates neuronal loss in chronic neurodegenerative diseases. This may be applicable to TBI, which also triggers inflammatory and apoptotic processes. Additionally, preliminary data support the use of pharmacological therapies that reduce apoptosis and inflammation associated with TBI. The anti-apoptotic and anti-inflammatory mechanisms of TUDCA could prove promising in the treatment of TBI. Currently, there are no published data supporting improvement in clinical outcomes of TBI by treatment with TUDCA, but future studies should be considered.

Topics: Animals; Anti-Inflammatory Agents; Apoptosis; Brain Injuries, Traumatic; Humans; Neuroprotective Agents; Taurochenodeoxycholic Acid

There are two forms of transthyretin (TTR) amyloidosis: non-hereditary and hereditary. The non-hereditary form (ATTRwt) is caused by native or wild-type TTR and was previously referred to as senile systemic amyloidosis. The hereditary form (ATTRm) is caused by variant TTR which results from a genetic mutation of TTR. The predominant effect of ATTRwt amyloidosis is on the heart, with patients having a greater left ventricular wall thickness at presentation than the devastating form which is light chain (AL) amyloidosis. ATTRm amyloidosis is broadly split into two categories: a type that predominantly affects the nervous system (often called familial amyloid polyneuropathy (FAP)) and one with a predilection for the heart (often called familial amyloid cardiomyopathy (FAC)). Approximately half of all TTR mutations known to express a clinical phenotype cause a cardiomyopathy. Since the introduction of orthotopic liver transplantation for ATTRm amyloidosis in 1991, several additional therapies have been developed. These therapies aim to provide a reduction or elimination of TTR from the plasma (through genetic approaches), stabilisation of the TTR molecule (to prevent deposition) and dissolution of the amyloid matrix. We describe the latest developments in these approaches to management, many of which are also applicable to wild-type amyloidosis.

Topics: Amyloid Neuropathies, Familial; Anti-Inflammatory Agents, Non-Steroidal; Benzoxazoles; Doxycycline; Echocardiography; Humans; Liver Transplantation; Molecular Targeted Therapy; Prealbumin; Prognosis; RNA, Small Interfering; Taurochenodeoxycholic Acid

Patients with familial amyloidpolyneuropathies (FAP) require multidisciplinary neurologic and cardiologic management, including specific treatments to control the progression of systemic amyloidogenesis, symptomatic treatment of peripheral and autonomic neuropathies, and management of severe organ involvement (heart, eyes, kidneys). The first-line specific treatment of choice for met30 TTR-FAP is liver transplantation (LT) which suppresses the main source of mutant TTR, halts the progression of neuropathy in 70% of cases, and doubles the median survival time. Dual kidney-liver or heart-liver transplantation may be appropriate for patients with severe renal or cardiac failure. Tafamidis (Vyndaqel(R), Pfizer), a novel stabilizer of tetrameric TTR, has shown short-term effectiveness in slowing the progression of peripheral neuropathy in very early stages of met30 TTR-FAP This drug should thus be proposed for stage 1 symptomatic polyneuropathy. Other innovative medicines (RNA interference, antisense oligonucleotides) have been developed to block hepatic production of both mutant and wildtype TTR (noxious in late-onset forms of NAH after age 50 years), and to remove amyloid deposits (monoclonal anti-SAP). Clinical trials should first include patients with late-onset FAP or non-met30 TTR-FAP who are less responsive to LT7 and patients in whom Vyndaqel(R) is ineffective or inappropriate. Initial and periodic cardiac assessment is necessary, as cardiac impairment is inevitable and largely responsible for mortality. Symptomatic treatment is crucial to improve these patients' quality of life. Familial screening for carriers of the TTR gene mutation and regular clinical examination are essential to detect disease onset and to start specific therapy in a timely manner.

Topics: Amyloid Neuropathies, Familial; Antibodies, Monoclonal; Benzoxazoles; Clinical Trials as Topic; Diflunisal; Disease Progression; Doxycycline; Drug Therapy, Combination; Genetic Therapy; Heart Failure; Heart Transplantation; Humans; Kidney Failure, Chronic; Kidney Transplantation; Liver Transplantation; Myocardium; Oligonucleotides, Antisense; Renal Dialysis; RNA Interference; Serum Amyloid P-Component; Taurochenodeoxycholic Acid

In the context of obesity and its related maladies, the adipocyte plays a central role in the balance, or imbalance, of metabolic homeostasis. An obese, hypertrophic adipocyte is challenged by many insults, including surplus energy, inflammation, insulin resistance, and considerable stress to various organelles. The endoplasmic reticulum (ER) is one such vital organelle that demonstrates significant signs of stress and dysfunction in obesity and insulin resistance. Under normal conditions, the ER must function in the unique and trying environment of the adipocyte, adapting to meet the demands of increased protein synthesis and secretion, energy storage in the form of triglyceride droplet formation, and nutrient sensing that are particular to the differentiated fat cell. When nutrients are in pathological excess, the ER is overwhelmed and the unfolded protein response (UPR) is activated. Remarkably, the consequences of UPR activation have been causally linked to the development of insulin resistance through a multitude of possible mechanisms, including c-jun N-terminal kinase activation, inflammation, and oxidative stress. This review will focus on the function of the ER under normal conditions in the adipocyte and the pathological effects of a stressed ER contributing to adipocyte dysfunction and a thwarted metabolic homeostasis.

Topics: Adipocytes; Animals; Cholesterol; Endoplasmic Reticulum; Humans; Inflammation; Lipid Metabolism; Metabolic Diseases; Obesity; Phenylbutyrates; Protein Folding; Proteins; Stress, Physiological; Taurochenodeoxycholic Acid

Liver transplantation has become a widely accepted form of treatment for numerous end-stage liver diseases. Bile acids may decrease the degree of allograft rejection after liver transplantation by changing the expression of major histocompatibility complex class molecules in bile duct epithelium and central vein endothelium.. To assess the beneficial and harmful effects of bile acids for liver-transplanted patients.. We performed searches of the Cochrane Hepato-Biliary Group Trials Register, the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, and EMBASE to April 2003. We also searched The Chinese Biomedical Database to May 2002.. Randomised clinical trials comparing any dose of bile acids or duration of treatment in liver-transplanted patients versus placebo, no intervention, or another intervention. We included randomised clinical trials irrespective of blinding, language, and publication status.. W Chen extracted the data and C Gluud validated them. We evaluated the methodological quality of the trials from the method for generation of the allocation sequence, allocation concealment, double blinding, and follow-up. We used the intention-to-treat principle to perform meta-analyses and presented the outcomes as relative risk (RR) or weighted mean difference (WMD), both with 95% confidence intervals (CI).. We identified seven randomised trials (six evaluating ursodeoxycholic acid versus placebo or no intervention and one evaluating tauro-ursodeoxycholic acid versus no intervention) with a total of 335 liver-transplanted patients. The administration of bile acids began one day or more after liver transplantation. All patients received the standard triple-drug immunosuppressive regimen (steroids, azathioprine, and cyclosporine or tacrolimus) to suppress the allograft rejection response after liver transplantation. Bile acids did not significantly reduce all-cause mortality, mortality related to allograft rejection, retransplantation, acute cellular rejection, or number of patients with steroid-resistant rejection. Bile acids significantly reduced the number of patients who had chronic rejection in a fixed-effect model but not in a random-effects model. Bile acids were safe and well tolerated by liver-transplanted patients.. Bile acids do not seem to have significant beneficial effects in liver-transplanted patients.

Topics: Cholagogues and Choleretics; Graft Rejection; Humans; Liver Transplantation; Randomized Controlled Trials as Topic; Taurochenodeoxycholic Acid; Ursodeoxycholic Acid

The viral hepatitides are common causes of liver diseases globally. Trials have assessed bile acids for patients with viral hepatitis, but no consensus was reached regarding their usefulness.. To assess the beneficial and harmful effects of bile acids for viral hepatitis.. Searches were performed of the trial registers of The Cochrane Hepato-Biliary Group (September 2002), The Cochrane Library (Issue 2, 2002), MEDLINE (September 2002), EMBASE (September 2002), and The Chinese Biomedical Database (April 2001).. Randomised clinical trials comparing any dose or duration of bile acids versus placebo or no intervention for viral hepatitis were included, irrespective of language, publication status, or blinding.. Two reviewers extracted the data independently. The methodological quality of the trials was evaluated with respect to generation of the allocation sequence, allocation concealment, double blinding, and follow-up. The outcomes were presented as relative risks (RR) or weighted mean differences (WMD) with 95% confidence intervals (CI).. We identified 27 randomised trials of bile acids for hepatitis B or C; none were of high methodological quality. In one trial, ursodeoxycholic acid (UDCA) versus placebo for acute hepatitis B significantly reduced the risk of hepatitis B surface antigen positivity at the end of treatment and serum HBV DNA level at the end of follow-up. In another trial, UDCA versus no intervention for chronic hepatitis B significantly reduced the risk of having abnormal serum transaminase activities at the end of treatment. Twenty-five trials compared bile acids (21 trials UDCA; four trials tauro-UDCA) versus placebo or no intervention with or without co-interventions for chronic hepatitis C. Bile acids did not significantly reduce the risk of having detectable serum HCV RNA (RR 0.99, 95% CI 0.91 to 1.07), cirrhosis, or portal and periportal inflammation score at the end of treatment. Bile acids significantly decreased the risk of having abnormal serum alanine aminotransferase activity at the end of treatment (RR 0.82, 95% CI 0.76 to 0.90) and follow-up (RR 0.91, 95% CI 0.85 to 0.98). Bile acids significantly increased the Knodell score (WMD 0.20, 95% CI 0.08 to 0.31) at the end of treatment. No severe adverse events were reported. We did not identify trials including patients with hepatitis A, acute C, D, or E.. Bile acids lead to a significant improvement in serum transaminase activities in hepatitis B and C. There is insufficient evidence either to support or to refute effects on viral markers, mortality, incidence of cirrhosis, or liver histology. Trials with high methodological quality are required.

Topics: Antiviral Agents; Hepatitis B, Chronic; Hepatitis C, Chronic; Hepatitis, Viral, Human; Humans; Randomized Controlled Trials as Topic; Taurochenodeoxycholic Acid; Ursodeoxycholic Acid

The aim of this paper is to point out that: 1) CDCA and DCA increase the polarity of cell membranes and cause the release of cholesterol and phospholipid from the membranes; 2) the extent of this damage is inversely correlated with the cholesterol content of the membrane investigated; 3) UDCA, TUDCA and GUDCA decrease membrane polarity; 4) they prevent membrane damage when added prior to CDCA or DCA; 5) UDCA appears to be incorporated into the apolar domain of the membrane, TUDCA, GUDCA into the interface; 6) UDCA decreases HLA class I expression on hepatocyte membranes; 7) CDCA induces GLDH-release from liver mitochondria and increases mitochondrial membrane polarity and mobility; and 8) UDCA reduces the release of GLDH from mitochondria caused by CDCA.

Topics: Animals; Cell Membrane; Chenodeoxycholic Acid; Cholesterol; Deoxycholic Acid; Histocompatibility Antigens Class I; Humans; Liver; Membrane Lipids; Phospholipids; Taurochenodeoxycholic Acid; Ursodeoxycholic Acid

Topics: Animals; Bile; Cholic Acids; Isomerism; Taurochenodeoxycholic Acid; Ursidae

An orally administered, fixed-dose coformulation of sodium phenylbutyrate-taurursodiol (PB-TURSO) significantly slowed functional decline in a randomized, placebo-controlled, phase 2 trial in ALS (CENTAUR). Herein we report results of a long-term survival analysis of participants in CENTAUR. In CENTAUR, adults with ALS were randomized 2:1 to PB-TURSO or placebo. Participants completing the 6-month (24-week) randomized phase were eligible to receive PB-TURSO in the open-label extension. An all-cause mortality analysis (35-month maximum follow-up post-randomization) incorporated all randomized participants. Participants and site investigators were blinded to treatment assignments through the duration of follow-up of this analysis. Vital status was obtained for 135 of 137 participants originally randomized in CENTAUR. Median overall survival was 25.0 months among participants originally randomized to PB-TURSO and 18.5 months among those originally randomized to placebo (hazard ratio, 0.56; 95% confidence interval, 0.34-0.92; P = .023). Initiation of PB-TURSO treatment at baseline resulted in a 6.5-month longer median survival as compared with placebo. Combined with results from CENTAUR, these results suggest that PB-TURSO has both functional and survival benefits in ALS.

Topics: Adolescent; Adult; Aged; Aged, 80 and over; Amyotrophic Lateral Sclerosis; Double-Blind Method; Female; Humans; Male; Middle Aged; Neuroprotective Agents; Phenylbutyrates; Taurochenodeoxycholic Acid; Time; Young Adult

Sodium phenylbutyrate and taurursodiol have been found to reduce neuronal death in experimental models. The efficacy and safety of a combination of the two compounds in persons with amyotrophic lateral sclerosis (ALS) are not known.. In this multicenter, randomized, double-blind trial, we enrolled participants with definite ALS who had had an onset of symptoms within the previous 18 months. Participants were randomly assigned in a 2:1 ratio to receive sodium phenylbutyrate-taurursodiol (3 g of sodium phenylbutyrate and 1 g of taurursodiol, administered once a day for 3 weeks and then twice a day) or placebo. The primary outcome was the rate of decline in the total score on the Amyotrophic Lateral Sclerosis Functional Rating Scale-Revised (ALSFRS-R; range, 0 to 48, with higher scores indicating better function) through 24 weeks. Secondary outcomes were the rates of decline in isometric muscle strength, plasma phosphorylated axonal neurofilament H subunit levels, and the slow vital capacity; the time to death, tracheostomy, or permanent ventilation; and the time to death, tracheostomy, permanent ventilation, or hospitalization.. A total of 177 persons with ALS were screened for eligibility, and 137 were randomly assigned to receive sodium phenylbutyrate-taurursodiol (89 participants) or placebo (48 participants). In a modified intention-to-treat analysis, the mean rate of change in the ALSFRS-R score was -1.24 points per month with the active drug and -1.66 points per month with placebo (difference, 0.42 points per month; 95% confidence interval, 0.03 to 0.81; P = 0.03). Secondary outcomes did not differ significantly between the two groups. Adverse events with the active drug were mainly gastrointestinal.. Sodium phenylbutyrate-taurursodiol resulted in slower functional decline than placebo as measured by the ALSFRS-R score over a period of 24 weeks. Secondary outcomes were not significantly different between the two groups. Longer and larger trials are necessary to evaluate the efficacy and safety of sodium phenylbutyrate-taurursodiol in persons with ALS. (Funded by Amylyx Pharmaceuticals and others; CENTAUR ClinicalTrials.gov number, NCT03127514.).

Topics: Aged; Amyotrophic Lateral Sclerosis; Disease Progression; Double-Blind Method; Drug Combinations; Female; Humans; Intention to Treat Analysis; Male; Middle Aged; Phenylbutyrates; Severity of Illness Index; Taurochenodeoxycholic Acid; Treatment Outcome

To investigate the effect of tauroursodeoxycholic acid (TUDCA) on neurological impairment induced by acute cerebral infarction (ACI) and its relevant mechanism of action.. A total of 60 male Sprague-Dawley (SD) rats were randomly divided into Sham group (n = 20), ACI group (n = 20), and TUDCA group (n = 20). The rat model of ACI in middle cerebral artery was established. TUDCA was intravenously injected into rats in the TUDCA group, while an equal amount of sodium bicarbonate solution was intravenously injected into the other two groups. The blood was drawn after modeling to detect the content of serum glutamate (Glu), triglyceride (TG), total cholesterol (TC), and low-density lipoprotein cholesterol (LDL-C). The degree of cerebral infarction in each experimental group was observed under an optical microscope, and the infarct area was measured and compared. The content of serum tumor necrosis factor-α (TNF-α), interleukin-8 (IL-8), and high-sensitivity C-reactive protein (hs-CRP) was detected via enzyme-linked immunosorbent assay (ELISA); mRNA and protein expressions of them were detected using reverse transcription-polymerase chain reaction (RT-PCR) and Western blotting, respectively, followed by statistical analysis. Moreover, the expression levels of serum malondialdehyde (MDA), oxidized-LDL (ox-LDL), superoxide dismutase (SOD), and glutathione peroxidase (GPX) were detected, followed by statistical analysis. The protein expressions of nuclear factor (erythroid-derived 2)-like 2 (Nrf2), very low-density lipoprotein receptor (VLDLR), nuclear factor-κB (NF-κB), B-cell lymphoma 2-associated X protein (Bax), and caspase-3 were detected via Western blotting, and the gray value was determined, followed by statistical analysis.. TUDCA could improve the symptoms of neurological impairment in ACI patients, decrease the National Institute of Health Stroke Scale (NIHSS) score but increase the activity of daily living (ADL) score of patients, and significantly reduce the content of serum TG, TC, and LDL-C, showing statistically significant differences (p < 0.05). TUDCA significantly decreased the serum Glu content in ACI rats, reduced the cerebral infarction area and lowered the serum TG, TC, and LDL-C content, displaying statistically significant differences (p < 0 .05). Besides, TUDCA inhibited mRNA and protein expressions of TNF-α, IL-8, and hs-CRP, and alleviated the inflammatory response. TUDCA inhibited MDA and ox-LDL expressions, but increased SOD and GPX expressions, and relieved oxidative stress injury. In addition, TUDCA could negatively regulate Nrf2 signaling pathway, and down-regulated VLDLR and NF-κB protein expressions and expressions of apoptotic proteins (Bax and caspase-3).. TUDCA can alleviate the ACI-induced neurological impairment in rats through mitigating lipid peroxidation and inflammatory response and reducing apoptosis, whose relevant mechanism may be that TUDCA negatively regulates Nrf2 signaling pathway.

Topics: Administration, Oral; Animals; Apoptosis; Cerebral Infarction; Disease Models, Animal; Down-Regulation; Female; Humans; Injections, Intravenous; Lipid Peroxidation; Male; Middle Aged; NF-E2-Related Factor 2; Oxidative Stress; Rats; Rats, Sprague-Dawley; Severity of Illness Index; Signal Transduction; Taurochenodeoxycholic Acid; Treatment Outcome

Tauroursodeoxycholic acid (TUDCA) is a hydrophilic bile acid that is produced in the liver and used for treatment of chronic cholestatic liver diseases. Experimental studies suggest that TUDCA may have cytoprotective and anti-apoptotic action, with potential neuroprotective activity. A proof of principle approach was adopted to provide preliminary data regarding the efficacy and tolerability of TUDCA in a series of patients with amyotrophic lateral sclerosis (ALS).. As a proof of principle, using a double-blind placebo controlled design, 34 ALS patients under treatment with riluzole who were randomized to placebo or TUDCA (1 g twice daily for 54 weeks) were evaluated after a lead-in period of 3 months. The patients were examined every 6 weeks. The primary outcome was the proportion of responders [those subjects with improvement of at least 15% in the Amyotrophic Lateral Sclerosis Functional Rating Scale Revised (ALSFRS-R) slope during the treatment period compared to the lead-in phase]. Secondary outcomes included between-treatment comparison of ALSFRS-R at study end, comparison of the linear regression slopes for ALSFFRS-R mean scores and the occurrence of adverse events.. Tauroursodeoxycholic acid was well tolerated; there were no between-group differences for adverse events. The proportion of responders was higher under TUDCA (87%) than under placebo (P = 0.021; 43%). At study end baseline-adjusted ALSFRS-R was significantly higher (P = 0.007) in TUDCA than in placebo groups. Comparison of the slopes of regression analysis showed slower progression in the TUDCA than in the placebo group (P < 0.01).. This pilot study provides preliminary clinical data indicating that TUDCA is safe and may be effective in ALS.

Topics: Adult; Aged; Amyotrophic Lateral Sclerosis; Double-Blind Method; Drug Therapy, Combination; Female; Humans; Male; Middle Aged; Neuroprotective Agents; Outcome Assessment, Health Care; Pilot Projects; Riluzole; Taurochenodeoxycholic Acid

Postprandial hyperglycaemia leads to a transient impairment in endothelial function; however, the mechanisms remain largely unknown. Previous work in cell culture models demonstrate that high glucose results in endoplasmic reticulum (ER) stress and, in animal studies, ER stress has been implicated as a cause of endothelial dysfunction. In the present study, we tested the hypothesis that acute oral administration of tauroursodeoxycholic acid (TUDCA, 1500 mg), a chemical chaperone known to alleviate ER stress, would prevent hyperglycaemia-induced endothelial dysfunction. In 12 young healthy subjects (seven men, five women), brachial artery flow-mediated dilation (FMD) was assessed at baseline, and at 60 and 120 min after an oral glucose challenge. Subjects were tested on two separate visits in a single-blind randomized cross-over design: after oral ingestion of TUDCA or placebo capsules. FMD was reduced from baseline during hyperglycaemia under the placebo condition (-32% at 60 min and -28% at 120 min post oral glucose load; P<0.05 from baseline) but not under the TUDCA condition (-4% at 60 min and +0.3% at 120 min post oral glucose load; P>0.05 from baseline). Postprandial plasma glucose and insulin were not altered by TUDCA ingestion. Plasma oxidative stress markers 3-nitrotyrosine and thiobarbituric acid reactive substance (TBARS) remained unaltered throughout the oral glucose challenge in both conditions. These results suggest that hyperglycaemia-induced endothelial dysfunction can be mitigated by oral administration of TUDCA, thus supporting the hypothesis that ER stress may contribute to endothelial dysfunction during postprandial hyperglycaemia.

Topics: Adult; Blood Glucose; Cardiovascular Diseases; Endoplasmic Reticulum Stress; Endothelium, Vascular; Female; Humans; Hyperglycemia; Insulin; Male; Oxidative Stress; Postprandial Period; Taurochenodeoxycholic Acid; Thiobarbituric Acid Reactive Substances; Tyrosine; Young Adult

Tauroursodeoxycholic acid (TUDCA) is a taurine conjugated form of ursodeoxycholic acid (UDCA) with higher hydrophility. To further evaluate the efficacy and safety of TUDCA for primary biliary cholangitis (PBC), we performed this study on Chinese patients.. 199 PBC patients were randomly assigned to either 250 mg TUDCA plus UDCA placebo or 250 mg UDCA plus TUDCA placebo, 3 times per day for 24 weeks. The primary endpoint was defined as percentage of patients achieving serum alkaline phosphatase (ALP) reduction of more than 25% from baseline.. At week 24, 75.97% of patients in the TUDCA group and 80.88% of patients in the UDCA group achieved a serum ALP reduction of more than 25% from baseline (P = 0.453). The percentage of patients with serum ALP levels declined more than 40% following 24 weeks of treatment was 55.81% in the TUDCA group and 52.94% in the UDCA group (P = 0.699). Both groups showed similar improvement in serum levels of ALP, aspartate aminotransferase, and total bilirubin (P > 0.05). The proportion of patients with pruritus/scratch increased from 1.43% to 10.00% in UDCA group, while there's no change in TUDCA group (P = 0.023). Both drugs were well tolerated, with comparable adverse event rates between the 2 groups.. TUDCA is safe and as efficacious as UDCA for the treatment of PBC, and may be better to relieve symptoms than UDCA.

Topics: Adolescent; Adult; Aged; Alkaline Phosphatase; China; Cholagogues and Choleretics; Cholangitis; Double-Blind Method; Female; Humans; Male; Middle Aged; Taurochenodeoxycholic Acid; Treatment Outcome; Ursodeoxycholic Acid

No direct comparison of tauroursodeoxycholic acid (TUDCA) and ursodeoxycholic acid (UDCA) has yet been carried out in the treatment of liver cirrhosis in China. We designed a double-blind randomized trial to evaluate the potential therapeutic efficacy of TUDCA in liver cirrhosis, using UDCA as parallel control. The enrolled 23 patients with liver cirrhosis were randomly divided into TUDCA group (n=12) and UDCA group (n=11), and given TUDCA and UDCA respectively at the daily dose of 750 mg, in a randomly assigned sequence for a 6-month period. Clinical, biochemical and histological features, and liver ultrasonographic findings were evaluated before and after the study. According to the inclusion criteria, 18 patients were included in the final analysis, including 9 cases in both two groups. Serum ALT, AST and ALP levels in TUDCA group and AST levels in UDCA group were significantly reduced as compared with baseline (P<0.05). Serum albumin levels were significantly increased in both TUDCA and UDCA groups (P<0.05). Serum markers for liver fibrosis were slightly decreased with the difference being not significant in either group. Only one patient in TUDCA group had significantly histological relief. Both treatments were well tolerated and no patient complained of side effects. It is suggested that TUDCA therapy is safe and appears to be more effective than UDCA in the treatment of liver cirrhosis, particularly in the improvement of the biochemical expression. However, both drugs exert no effect on the serum markers for liver fibrosis during 6-month treatment.

Topics: Adult; Cholagogues and Choleretics; Double-Blind Method; Female; Humans; Liver Cirrhosis; Male; Middle Aged; Taurochenodeoxycholic Acid; Treatment Outcome; Ursodeoxycholic Acid

We designed a phase II, open-label study to evaluate the efficacy, tolerability, safety, and pharmacokinetics of orally doxycycline (100 mg BID) and tauroursodeoxycholic acid (TUDCA) (250 mg three times/day) administered continuously for 12 months. Primary endpoint is response rate defined as nonprogression of the neuropathy and of the cardiomyopathy. Since July 2010, we enrolled 20 patients. Seventeen patients have hereditary ATTR, two patients have senile systemic amyloidosis, and one is a domino recipient. Seven patients completed 12-month treatment, 10 completed 6-month treatment, two discontinued because of poor tolerability, and one is lost at follow-up. No serious adverse events were registered. No clinical progression of cardiac involvement was observed. The neuropathy (Neuropathy Impairment Score in the Lower Limbs [NIS-LL] and Kumamoto score) remained substantially stable over 1 year. These preliminary data indicate that the combination of Doxy-TUDCA stabilizes the disease for at least 1 year in the majority of patients with an acceptable toxicity profile.

Topics: Adult; Aged; Amyloid Neuropathies, Familial; Doxycycline; Drug Administration Schedule; Female; Humans; Male; Middle Aged; Prealbumin; Taurochenodeoxycholic Acid; Treatment Outcome

Insulin resistance is commonly associated with obesity. Studies conducted in obese mouse models found that endoplasmic reticulum (ER) stress contributes to insulin resistance, and treatment with tauroursodeoxycholic acid (TUDCA), a bile acid derivative that acts as a chemical chaperone to enhance protein folding and ameliorate ER stress, increases insulin sensitivity. The purpose of this study was to determine the effect of TUDCA therapy on multiorgan insulin action and metabolic factors associated with insulin resistance in obese men and women.. Twenty obese subjects ([means +/- SD] aged 48 +/- 11 years, BMI 37 +/- 4 kg/m2) were randomized to 4 weeks of treatment with TUDCA (1,750 mg/day) or placebo. A two-stage hyperinsulinemic-euglycemic clamp procedure in conjunction with stable isotopically labeled tracer infusions and muscle and adipose tissue biopsies were used to evaluate in vivo insulin sensitivity, cellular factors involved in insulin signaling, and cellular markers of ER stress. RESULTS Hepatic and muscle insulin sensitivity increased by approximately 30% (P < 0.05) after treatment with TUDCA but did not change after placebo therapy. In addition, therapy with TUDCA, but not placebo, increased muscle insulin signaling (phosphorylated insulin receptor substrate(Tyr) and Akt(Ser473) levels) (P < 0.05). Markers of ER stress in muscle or adipose tissue did not change after treatment with either TUDCA or placebo.. These data demonstrate that TUDCA might be an effective pharmacological approach for treating insulin resistance. Additional studies are needed to evaluate the target cells and mechanisms responsible for this effect.

Topics: Adiponectin; Adipose Tissue; Adult; Blood Glucose; Cholagogues and Choleretics; Female; Glucose Clamp Technique; Humans; Insulin; Insulin Resistance; Liver; Male; Middle Aged; Muscle, Skeletal; Obesity; Organ Specificity; Placebos; Taurochenodeoxycholic Acid; Triglycerides

To develop a new formulation with hydroxy propyl methyl cellulose and Shellac coating for extended and selective delivery of butyrate in the ileo-caecal region and colon.. One-gram sodium butyrate coated tablets containing 13C-butyrate were orally administered to 12 healthy subjects and 12 Crohn's disease patients and the rate of 13C-butyrate absorption was evaluated by 13CO2 breath test analysis for eight hours. Tauroursodeoxycholic acid (500 mg) was co-administered as a biomarker of oro-ileal transit time to determine also the site of release and absorption of butyrate by the time of its serum maximum concentration.. The coated formulation delayed the 13C-butyrate release by 2-3 h with respect to the uncoated tablets. Sodium butyrate was delivered in the intestine of all subjects and a more variable transit time was found in Crohn's disease patients than in healthy subjects. The variability of the peak 13CO2 in the kinetic release of butyrate was explained by the inter-subject variability in transit time. However, the coating chosen ensured an efficient release of the active compound even in patients with a short transit time.. Simultaneous evaluation of breath 13CO2 and tauroursodeoxycholic acid concentration-time curves has shown that the new oral formulation consistently releases sodium butyrate in the ileo-cecal region and colon both in healthy subjects and Crohn's disease patients with variable intestinal transit time. This formulation may be of therapeutic value in inflammatory bowel disease patients due to the appropriate release of the active compound.

Topics: Administration, Oral; Adolescent; Adult; Aged; Butyrates; Carbon Dioxide; Carbon Isotopes; Cecum; Chemistry, Pharmaceutical; Colon; Crohn Disease; Female; Humans; Ileum; Male; Middle Aged; Sodium; Tablets, Enteric-Coated; Taurochenodeoxycholic Acid

To determine whether tauroursodeoxycholic acid (TUDCA) would prevent or ameliorate the liver injury in neonates treated with total parenteral nutrition (TPN).. Eligible infants were enrolled after surgery when serum direct bilirubin (DB) was <2 mg/dL. TUDCA (30 mg/kg/day) was given enterally to 22 subjects. A concurrent untreated/placebo group was evaluated for comparison (n = 30). Blood chemistries including alanine aminotransferase (ALT), alkaline phosphatase (AP), conjugated bilirubin (CB), and bile acids (BA) were obtained weekly.. There was no difference in peak serum CB, ALT, AP, or BA levels between the TUDCA-treated and control infants. When stratified for birth weight (<1500 g and >1500 g), no differences in peak CB, ALT, AP, or BA were noted. Serum CB levels were similar between TUDCA-treated and control infants after 14, 40, 60, 70, and 120 days of TPN.. TUDCA appears ineffective in preventing the development or treatment of TPN-associated cholestasis in neonates. Erratic biliary enrichment and prolonged inability to initiate treatment may compromise the utility of enterically administered TUDCA for TPN-treated infants.

Topics: Alanine Transaminase; Alkaline Phosphatase; Bile Acids and Salts; Bilirubin; Biomarkers; Birth Weight; Cholagogues and Choleretics; Enteral Nutrition; Humans; Infant; Infant Welfare; Infant, Newborn; Infant, Very Low Birth Weight; Liver Diseases; Minnesota; Mississippi; Ohio; Parenteral Nutrition, Total; Taurochenodeoxycholic Acid; Texas; Time Factors

Topics: Adenosine; Adult; Allopurinol; Cholagogues and Choleretics; Glutathione; Humans; Insulin; Liver; Liver Transplantation; Middle Aged; Organ Preservation; Organ Preservation Solutions; Raffinose; Reperfusion Injury; Taurochenodeoxycholic Acid; Transplantation, Homologous

The clinical effectiveness of ursodeoxycholate in the treatment of liver disease may be limited by its poor absorption and extensive biotransformation. Because in vitro and in vivo studies suggest that the more hydrophilic bile acid tauroursodeoxycholate has greater beneficial effects than ursodeoxycholate, we have compared for the first time the absorption, metabolism, and clinical responses to these bile acids in patients with primary biliary cirrhosis (PBC). Twelve female patients with PBC were sequentially administered tauroursodeoxycholate and ursodeoxycholate (750 mg/d for 2 months) in a randomized, cross-over study. Bile acids were measured in serum, duodenal bile, urine, and feces by gas chromatography-mass spectrometry (GC-MS). Biliary ursodeoxycholate enrichment was higher during tauroursodeoxycholate administration (32.6% vs. 29.2% during ursodeoxycholate; P <.05). Lithocholic acid concentration was consistently higher in all biological fluids during ursodeoxycholate administration. Fecal bile acid excretion was the major route of elimination of both bile acids; ursodeoxycholate accounted for 8% and 23% of the total fecal bile acids during tauroursodeoxycholate and ursodeoxycholate administration, respectively (P <.05). Tauroursodeoxycholate was better absorbed than ursodeoxycholate, and, although it was partially deconjugated and reconjugated with glycine, it underwent reduced biotransformation to more hydrophobic metabolites. This comparative study suggests that tauroursodeoxycholate has significant advantages over ursodeoxycholate that may be of benefit for long-term therapy in PBC.

Topics: Absorption; Adult; Aged; Bile; Bile Acids and Salts; Cross-Over Studies; Duodenum; Feces; Female; Gas Chromatography-Mass Spectrometry; Humans; Lithocholic Acid; Liver Cirrhosis, Biliary; Middle Aged; Taurochenodeoxycholic Acid; Ursodeoxycholic Acid

Results from animal studies and preliminary data from pilot studies in patients with primary biliary cirrhosis suggest that tauro-ursodeoxycholic acid has metabolic properties that may favour its long-term use as an alternative to ursodeoxycholic acid for patients with chronic cholestatic liver diseases. No direct comparison of tauro-ursodeoxycholic and ursodeoxycholic acids have yet been carried out in primary biliary cirrhosis.. The effects of ursodeoxycholic and tauro-ursodeoxycholic acids were compared in 23 patients with primary biliary cirrhosis according to a crossover design. Both drugs were administered at the daily dose of 500 mg. in a randomly assigned sequence for two 6-month periods separated by a 3-month wash-out period.. Serum liver enzymes related to cholestasis and cytolysis consistently improved, as compared to baseline values, during the administration of both ursodeoxycholic and tauro-ursodeoxycholic acids, but no significant difference between these two bile acids was found. Both treatments were well tolerated and no patient complained of side effects.. In the short-term, tauro-ursodeoxycholic acid appears to be safe and at least as effective as ursodeoxycholic acid for the treatment of primary biliary cirrhosis.

Topics: Cholagogues and Choleretics; Cross-Over Studies; Humans; Lipids; Liver; Liver Cirrhosis, Biliary; Middle Aged; Pilot Projects; Taurochenodeoxycholic Acid; Ursodeoxycholic Acid

Tauroursodeoxycholic acid, a highly hydrophilic bile acid, may be of therapeutic value for chronic cholestatic liver diseases. We performed a dose-response study on 24 patients with primary biliary cirrhosis who were randomly assigned to receive 500, 1000, or 1500 mg daily of tauroursodeoxycholic acid for six months. Biliary enrichment with ursodeoxycholic acid ranged from 15% to 48% and was not related with the dose. Serum liver enzyme levels decreased significantly after the first month of treatment with all the three doses. No significant difference among the three doses was found, although further reduction over time occurred with 1000 and 1500mg daily. Plasma total and HDL cholesterol significantly decreased in patients administered the two higher doses. Diarrhea was the only side effect. In conclusion, a dose of about 10mg/kg body wt/day of tauroursodeoxycholic acid should be used for long-term studies in patients with primary biliary cirrhosis.

Topics: Bile; Cholesterol; Cholesterol, HDL; Clinical Enzyme Tests; Dose-Response Relationship, Drug; Humans; Isomerism; Liver; Liver Cirrhosis, Biliary; Middle Aged; Taurochenodeoxycholic Acid; Time Factors

The metabolism of tauroursodeoxycholic acid orally administered and its effects on the bile acid pool of patients with asymptomatic/mildly symptomatic primary biliary cirrhosis is described. Patients were randomly assigned 500, 1000, or 1500 mg/day of tauroursodeoxycholate for six months. Biliary and serum bile acids were measured before and during treatment by gas chromatography-mass spectrometry and by high performance liquid chromatography. During tauroursodeoxycholate administration, the proportion of total ursodeoxycholate in bile reached mean (SEM) 34.4 (4.5)%, 32.8 (2.8)%, and 41.6 (3.0)% with doses of 500, 1000, and 1500 mg/day, respectively. Significant decreases in the proportions of chenodeoxycholate and cholate resulted. The glycine/taurine ratio of the biliary bile acid pool decreased from 1.9 at baseline, to 1.1 with the highest dose. Ursodeoxycholate in bile was conjugated with glycine and taurine, indicating that tauroursodeoxycholate undergoes significant deconjugation and reconjugation during its enterohepatic recycling. The proportion of lithocholate in bile remained unchanged. Fasting serum conjugated ursodeoxycholate concentration positively correlated with the tauroursodeoxycholate dose, and the increased proportion of ursodeoxycholate was accompanied by substantial decreases in the endogenous bile acids. Compared with previously published data for ursodeoxycholic acid therapy, these findings indicate that the shift toward a more hydrophilic bile acid pool is greater and potentially more favourable with tauroursodeoxycholate, and this is because of the reduced intestinal biotransformation of tauroursodeoxycholate.

Topics: Administration, Oral; Adult; Aged; Bile; Bile Acids and Salts; Chromatography, High Pressure Liquid; Drug Administration Schedule; Gas Chromatography-Mass Spectrometry; Humans; Intestinal Mucosa; Lithocholic Acid; Liver Cirrhosis, Biliary; Middle Aged; Taurochenodeoxycholic Acid; Ursodeoxycholic Acid

Tauroursodeoxycholic acid has been proposed for the treatment of hepatobiliary disease, but data on the enrichment of biliary tauroursodeoxycholic acid pool and on changes of biliary lipids after administration of the compound are scarce. We studied the composition of biliary lipids in a series of 33 patients with radiolucent stones, before and after treatment with tauroursodeoxycholic acid, 3.5 - 16.6 mg/kg/day for 4 - 6 weeks. Duodenal bile was collected with the Entero-Test after gallbladder contraction. Tauroursodeoxycholic acid administration produced the following dose-dependent effects: a linear decrease of cholesterol saturation (r = 0.59, p < 0.001); a non-linear increase of the percent of ursodeoxycholic acid in bile (r = 0.59, p < 0.001); a non-linear increase of the fraction of ursodeoxycholate conjugated with taurine. At the dose of 11 mg/kg per day, cholesterol saturation was 80%, ursodeoxycholic acid represented about 45% of biliary bile acids, and about half of UDCA was conjugated with taurine. Biliary bile acids were repeatedly measured in 6 patients during long-term treatment with 9.7 - 12.1 mg/kg. The fraction of tauroursodeoxycholic acid decreased progressively from 67.6% +/- 10.5 to 29.1% +/- 5. Tauroursodeoxycholic acid is as effective as ursodeoxycholic acid on a molar basis in reducing biliary cholesterol saturation and in enriching bile with ursodeoxycholate. Moreover, tauroursodeoxycholic acid administration is associated with higher concentrations of tauroconjugates in the bile than those previously reported by feeding the free bile acid.

Topics: Adult; Aged; Bile; Bile Acids and Salts; Cholelithiasis; Cholesterol; Dose-Response Relationship, Drug; Female; Humans; Lipid Metabolism; Male; Middle Aged; Taurochenodeoxycholic Acid

Out of 34 patients enrolled and randomized, 31 completed the 6 months study period. Fifteen were treated with TUDCA, and 16 with UDCA. Dosage for both drugs was 10 mg/kg body weight daily. Superiprisingly, TUDCA was not found to be more active than UDCA in dissolving, totally or partially, the gallbladder stones; indeed, total dissolution was more frequent in the UDCA group. Since the two groups were similar as to number and size of the stones, the better results with UDCA cannot be attributed to the characteristics of the calculosis but must be ascribed to the molecule used. Both drugs induced an improvement in dyspeptic symptoms, but from this point of view, too, UCDA was more effective than TUDCA (p < 0.01). Finally, tolerability was also significantly better for UDCA, although TUDCA was altogether acceptable.

Topics: Adolescent; Adult; Aged; Cholecystectomy; Cholelithiasis; Deoxycholic Acid; Drug Evaluation; Female; Humans; Male; Middle Aged; Single-Blind Method; Solubility; Taurochenodeoxycholic Acid

The effect of selenium on diabetes is significant. As pharmaceutical chaperones, tauroursodeoxycholic acid (TUDCA) and 4-phenylbutyric acid (4-PBA) can effectively improve the oxidative stress of the endoplasmic reticulum. This study established a mice model with type 1 diabetes (T1D) to evaluate the effects of pharmaceutical chaperones on selenium distribution. Streptozotocin was used to induce Friend virus B-type mice to establish a T1D mice model. Mice were administered with TUDCA or 4-PBA. Selenium levels in different tissues were measured by inductively coupled plasma-mass spectroscopy (ICP-MS). After treatment with TUDCA and 4-PBA, related laboratory findings such as glucose and glycated serum protein were significantly reduced and were closer to normal levels. At 2 weeks, 4-PBA normalized selenium levels in the heart, and 4-PBA and TUDCA maintained the selenium in the liver, kidney, and muscle at normal. At 2 months, 4-PBA and TUDCA maintained the selenium in the heart, liver, and kidney at normal levels. The serum selenium had a positive correlation with zinc and copper in the diabetes group and the control group, while the serum selenium had no significant association with magnesium and calcium at 2 weeks and 2 months. TUDCA and 4-PBA have crucial effects on selenium distribution in diabetic mice, and further research is needed to research their internal mechanisms.

Topics: Animals; Diabetes Mellitus, Experimental; Diabetes Mellitus, Type 1; Disease Models, Animal; Endoplasmic Reticulum Stress; Mice; Pharmaceutical Preparations; Selenium; Taurochenodeoxycholic Acid

Duyun compound green tea (DCGT) is a healthy beverage with lipid-lowering effect commonly consumed by local people, but its mechanism is not very clear. We evaluated the effect of DCGT treatment on bile acids (BA) metabolism of mice with high-fat diet (HFD) - induced hyperlipidaemia by biochemical indexes and metabolomics and preliminarily determined the potential biomarkers and metabolic pathways of hyperlipidaemia mice treated with DCGT as well as investigated its lipid-lowering mechanism. The results showed that DCGT treatment could reduce HFD - induced gain in weight and improve dyslipidaemia. In addition, a total of ten types of BA were detected, of which seven changed BA metabolites were observed in HFD group mice. After DCGT treatment, glycocholic acid, tauroursodeoxycholic acid and taurochenodeoxycholic acid were significantly down-regulated, while hyodeoxycholic acid, deoxycholic acid and chenodeoxycholic acid were markedly up-regulated. These results demonstrated that DCGT treatment was able to make the BA metabolites in the liver of hyperlipidaemia mice normal and alleviate hyperlipidaemia by regulating the metabolites such as glycocholic acid, tauroursodeoxycholic acid and taurochenodeoxycholic, as well as the BA metabolic pathway and cholesterol metabolic pathway involved.

Topics: Animals; Bile Acids and Salts; Cholesterol; Diet, High-Fat; Glycocholic Acid; Hyperlipidemias; Lipid Metabolism; Liver; Metabolic Diseases; Mice; Mice, Inbred C57BL; Plant Extracts; Taurochenodeoxycholic Acid; Tea

Topics: Humans; Phenylbutyrates; Taurochenodeoxycholic Acid

The bile acid tauroursodeoxycholic acid (TUDCA) is of natural origin and is used in traditional Chinese medicine for centuries. Earlier its use was limited to biliary disorders but owing to its pleiotropic effects dietary TUDCA supplementation is under clinical trials for diseases including type 1 and 2 diabetic complications. The current study aims to evaluate the potential and underlying molecular mechanism of the TUDCA as a monotherapy and as an add-on therapy to telmisartan, an angiotensin II type 1 receptor (AT1R) blocker against diabetic kidney disease (DKD). We employed both in-vitro and in-vivo approaches where NRK-52E cells were incubated with high glucose, and DKD was induced in Wistar rats using streptozotocin (55 mg/kg, i.p.). After 4 weeks, animals were administered with TUDCA (250 mg/kg, i.p.), telmisartan (10 mg/kg, p.o.), and their combination for 4 weeks. Plasma was collected for the biochemical estimation and kidneys were used for immunoblotting, PCR, and histopathological analysis. Similarly, for in-vitro experiments, cells were exposed to 1000 μM of TUDCA and 10 μM of telmisartan, and their combination, followed by cell lysate collection and immunoblotting analysis. We observed that the addition of TUDCA to conventional telmisartan treatment was more effective in restoring the renal function decline and suppressing the apoptotic and fibrotic signaling as compared to monotherapies of AT1R blocker and ER stress inhibitor. The results implicate the utility of traditionally used TUDCA as a potential renoprotective compound. Since, both TUDCA and telmisartan are approved for clinical usage, thus concomitant administration of them could be a novel therapeutic strategy against DKD.

Topics: Angiotensin II Type 1 Receptor Blockers; Animals; Diabetes Mellitus; Diabetic Nephropathies; Rats; Rats, Wistar; Streptozocin; Taurochenodeoxycholic Acid; Telmisartan

To determine 15 bile acid metabolic products in human serum by liquid chromatography-tandem mass spectrometry (LC/MS/MS) and value their diagnostic outcome in primary biliary cholangitis (PBC). Serum from 20 healthy controls and 26 patients with PBC were collected and went LC/MS/MS analysis of 15 bile acid metabolic products. The test results were analyzed by bile acid metabolomics, and the potential biomarkers were screened and their diagnostic performance was judged by statistical methods such as principal component and partial least squares discriminant analysis and area under curve (AUC). 8 differential metabolites can be screened out: Deoxycholic acid (DCA), Glycine deoxycholic acid (GDCA), Lithocholic acid (LCA), Glycine ursodeoxycholic acid (GUDCA), Taurolithocholic acid (TLCA), Tauroursodeoxycholic acid (TUDCA), Taurodeoxycholic acid (TDCA), Glycine chenodeoxycholic acid (GCDCA). The performance of the biomarkers was evaluated by the AUC, specificity and sensitivity. In conclusion, DCA, GDCA, LCA, GUDCA, TLCA, TUDCA, TDCA and GCDCA were identified as eight potential biomarkers to distinguish between healthy people and PBC patients by multivariate statistical analysis, which provided reliable experimental basis for clinical practice.

Topics: Bile Acids and Salts; Biomarkers; Chromatography, Liquid; Glycine; Humans; Liver Cirrhosis, Biliary; Tandem Mass Spectrometry; Taurochenodeoxycholic Acid

In this study, the effects of SCD Probiotics with tauroursodeoxycholic acid (TUDCA) application on the aged rat gut microbiota (GM) composition were investigated.. Twenty-four-month-old Sprague-Dawley rats were given 300 mg/kg of TUDCA along with 3 mL (1 × 108 CFU) of SCD probiotics for 7 days. The bacterial profile was determined by the metagenome applied to the cecum content. TUDCA, SCD probiotics, and TUDCA with SCD probiotics designed GM differently. TUDCA and SCD probiotics have the most different dominant species profiles.. SCD probiotics and TUDCA have their own unique effects on the species found in GM, and when they are evaluated together, the species found in GM are restructured differently.

Topics: Animals; Gastrointestinal Microbiome; Probiotics; Rats; Rats, Sprague-Dawley; Taurochenodeoxycholic Acid

Parkinson's disease (PD) is closely linked to lifestyle factors, particularly dietary patterns, which have attracted interest as potential disease-modifying factors. Eating a low-protein, high-carbohydrate (LPHC) diet is a promising dietary intervention against brain aging; however, its protective effect on PD remains elusive. Here, we found that an LPHC diet ameliorated 1-methyl-4-phenyl-1,2,3,6-tetrathydropyridine (MPTP)-induced motor deficits, decreased dopaminergic neuronal death, and increased the levels of striatal dopamine, serotonin, and their metabolites in PD mice. Levels of fibroblast growth factor 21 (FGF-21), a member of the fibroblast growth factor family, were elevated in PD mice following LPHC treatment. Furthermore, the administration of FGF-21 exerted a protective effect on MPTP-induced PC12 cells, similar to the effect of an LPHC diet in MPTP-induced mice. Sequencing of the 16S rDNA from fecal microbiota revealed that an LPHC diet normalized the gut bacterial composition imbalance in PD mice, as evidenced by the increased abundance of the genera

Topics: 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine; Animals; Brain; Diet; Disease Models, Animal; Dopamine; Fibroblast Growth Factors; Mice; Mice, Inbred C57BL; Microbiota; Neuroprotective Agents; Parkinson Disease; Taurochenodeoxycholic Acid

During embryo development, the endoplasmic reticulum (ER) acts as an important site for protein biosynthesis; however, in vitro culture (IVC) can negatively affect ER homeostasis. Therefore, the aim of our study was to evaluate the effects of the supplementation of tauroursodeoxycholic acid (TUDCA), an ER stress inhibitor, in the IVC of bovine embryos. Two experiments were carried out: Exp. 1: an evaluation of blastocyst rate, hatching kinetics, and gene expression of hatched embryos after being treated with different concentrations of TUDCA (50, 200, or 1000 μM) in the IVC; Exp. 2: an evaluation of the re-expansion, hatching, and gene expression of hatched embryos previously treated with 200 µM of TUDCA at IVC and submitted to vitrification. There was no increase in the blastocyst and hatched blastocyst rates treated with TUDCA in the IVC. However, embryos submitted to vitrification after treatment with 200 µM of TUDCA underwent an increased hatching rate post-warming together with a down-regulation in the expression of ER stress-related genes and the accumulation of lipids. In conclusion, this work showed that the addition of TUDCA during in vitro culture can improve the cryotolerance of the bovine blastocyst through the putative modulation of ER and oxidative stress.

Topics: Animals; Cattle; Dietary Supplements; Endoplasmic Reticulum; Taurochenodeoxycholic Acid

Persistent hyperglycemia in type 1 diabetes triggers numerous signaling pathways, which may prove deleterious to the endothelium. As hyperglycemia damages the endothelial layer via multiple signaling pathways, including enhanced oxidative stress, downregulation of angiotensin-converting enzyme 2 signaling, and exacerbation of endoplasmic reticulum (ER) stress, it becomes difficult to prevent injury using monotherapy. Thus, the present study was conceived to evaluate the combined effect of ER stress inhibition along with angiotensin-converting enzyme 2 activation, two major contributors to hyperglycemia-induced endothelial dysfunction, in preventing endothelial dysfunction associated with type 1 diabetes. Streptozotocin-induced diabetic animals were treated with either diminazene aceturate (5 mg·kg

Topics: Angiotensin-Converting Enzyme 2; Animals; Diabetes Mellitus, Experimental; Diabetes Mellitus, Type 1; Diminazene; Drug Therapy, Combination; Endoplasmic Reticulum Stress; Endothelium, Vascular; Male; Oxidative Stress; Rats, Wistar; Streptozocin; Taurochenodeoxycholic Acid

Spinal cord injury (SCI) causes cell death and consequently the breakdown of axons and myelin. The accumulation of myelin debris at the lesion site induces inflammation and blocks axonal regeneration. Hematogenous macrophages contribute to the removal of myelin debris. In this study, we asked how the inflammatory state of macrophages affects their ability to phagocytose myelin. Bone marrow-derived macrophages (BMDM) and Raw264.7 cells were stimulated with lipopolysaccharides (LPS) or interferon gamma (IFNγ), which induce inflammatory stress, and the endocytosis of myelin was examined. We found that activation of the TLR4-NFκB pathway reduced myelin uptake by BMDM, while IFNγ-Jak/STAT1 signaling did not. Since bile acids regulate lipid metabolism and in some cases reduce inflammation, our second objective was to investigate whether myelin clearance could be improved with taurolithocholic acid (TLCA), tauroursodeoxycholic acid or hyodeoxycholic acid. In BMDM only TLCA rescued myelin phagocytosis, when this activity was suppressed by LPS. Inhibition of protein kinase A blocked the effect of TLCA, while an agonist of the farnesoid X receptor did not rescue phagocytosis, implicating TGR5-PKA signaling in the effect of TLCA. To shed light on the mechanism, we measured whether TLCA affected the expression of CD36, triggering receptor on myeloid cells-2 (TREM2), and Gas6, which are known to be involved in phagocytosis and affected by inflammatory stimuli. Concomitant with an increase in expression of tumour necrosis factor alpha, LPS reduced expression of TREM2 and Gas6 in BMDM, and TLCA significantly diminished this downregulation. These findings suggest that activation of bile acid receptors may be used to improve myelin clearance in neuropathologies.

Topics: Humans; Inflammation; Lipopolysaccharides; Macrophages; Myelin Sheath; Phagocytosis; Taurochenodeoxycholic Acid; Taurolithocholic Acid

Septic arthritis induced by Staphylococcus aureus (S. aureus) causes irreversible cartilage degradation and subsequent permanent joint dysfunction. Recently, cartilage degradation in osteoarthritis is recognized to be associated with metabolic disorders. However, whether cholesterol metabolism is linked to septic arthritis pathology remains largely unknown. Here, we found that exposure to fermentation supernatant (FS) of S. aureus in chondrocytes resulted in a significant increase in expression of key modulators involved in cholesterol metabolism, including lectin-type oxidized low density lipoprotein receptor 1 (LOX1), cholesterol 25-hydroxylase (CH25H), 25- hydroxycholesterol 7α-hydroxylase (CYP7B1) as well as retinoic acid-related orphan receptor alpha (RORα), a binding receptor for cholesterol metabolites. We further demonstrated that enhancement of CH25H/CYP7B1/RORα axis resulted from FS exposure was mediated by activation of NF-κB signaling, along with upregulation in catabolic factors including matrix metallopeptidases (MMP3 and MMP13), aggrecanase-2 (ADAMTS5), and nitric oxide synthase-2 (NOS2) in chondrocytes. Exogenous cholesterol acts synergistically with FS in activating NF-κB pathway and increases cholesterol metabolism. While, the addition of tauroursodeoxycholic acid (TUDCA) which promotes cholesterol efflux, resulted in remarkable reduction of intracellular cholesterol level and restoration of balance between anabolism and catabolism in FS treated chondrocytes. Collectively, our data indicated that, in response to FS of S. aureus, NF-κB signaling activation coupled with increased cholesterol metabolism to stimulate catabolic factors in chondrocytes, highlighting cholesterol metabolism as a potential therapeutic target for treating septic arthritis.

Topics: ADAMTS5 Protein; Arthritis, Infectious; Cartilage; Cells, Cultured; Cholesterol; Chondrocytes; Cytochrome P450 Family 7; Gene Expression Regulation; Humans; Matrix Metalloproteinase 13; Metabolism; NF-kappa B; Nitric Oxide Synthase Type II; Nuclear Receptor Subfamily 1, Group F, Member 1; Osteoarthritis; Scavenger Receptors, Class E; Signal Transduction; Staphylococcus aureus; Steroid Hydroxylases; Taurochenodeoxycholic Acid; Transcription Factor RelA

Inflammatory response and renal fibrosis are the hallmarks of chronic kidney disease (CKD). However, the specific mechanism of aldosterone-induced renal injury in the progress of CKD requires elucidation. Emerging evidence has demonstrated that absent in melanoma 2 (AIM2)-mediated inflammasome activation and endoplasmic reticulum stress (ERS) play a pivotal role in the renal fibrosis. Here, we investigated whether overexpression or deficiency of AIM2 affects ERS and fibrosis in aldosterone-infused renal injury. Interestingly, we found that AIM2 was markedly expressed in the diseased proximal tubules from human and experimental CKD. Mechanically, overactivation of AIM2 aggravated aldosterone-induced ERS and fibrotic changes in vitro while knockdown of AIM2 blunted these effects in vivo and in vitro. By contrast, AIM2 deficiency ameliorated renal structure and function deterioration, decreased proteinuria levels and lowered systolic blood pressure in vivo; silencing of AIM2 blocked inflammasome-mediated signaling pathway, relieved ERS and fibrotic changes in vivo. Furthermore, mineralocorticoid receptor (MR) antagonist eplerenone and ERS inhibitor tauroursodeoxycholic acid (TUDCA) had nephroprotective effects on the basis of AIM2 overactivation in vitro, while they failed to produce a more remarkable renoprotective effect on the treatment of AIM2 silence in vitro. Notably, the combination of TUDCA with AIM2 knockdown significantly reduced proteinuria levels in vivo. Additionally, immunofluorescence assay identified that apoptosis-associated speck-like protein (ASC) recruitment and Gasdermin-D (GSDMD) cleavage respectively occurred in the glomeruli and tubules in vivo. These findings establish a crucial role for AIM2 inflammasome in aldosterone-induced renal injury, which may provide a novel therapeutic target for the pathogenesis of CKD.

Topics: Acute Kidney Injury; Aldosterone; Animals; DNA-Binding Proteins; Endoplasmic Reticulum Stress; Fibrosis; Inflammasomes; Male; Mice, Inbred C57BL; Renal Insufficiency, Chronic; Taurochenodeoxycholic Acid

To study the protective effect of tauroursodeoxycholic acid (TUDCA) on the spinal cord nerve cells (SCN) of SD rats and to explore the protective mechanism of TUDCA against mechanical injury of the SCN.. The SCN of SD rats were cultured in vitro, and a mechanical injury models of 1 mm, 3 mm, and 5 mm SCN were established. The cell survival rate was determined using the MTT assay to determine the optimal degree and time of injury. Different concentrations (0.5, to 20 mmol/L) of TUDCA were used to detect SCN cell survival rate after mechanical injury. MTT assay was used to determine the optimal TUDCA intervention dose. SCN autophagy in different experimental groups were observed by electron microscopy after the best degree of mechanical injury, time of injury, and TUDCA concentration. Beclin-1 and LC3 II/I expressions were detected by western blotting and immunohistochemistry.. Survival rate of SCN was close to 50% when the injury interval was 3 mm and the injury time was 24 h, significantly different from those of each group (P < 0.05). At 3 mm injury interval and 24 h injury time, SCN survival rate was approximately 80% when TUDCA concentration was 4 mmol/L, which was significantly different from those of each group (P < 0.05). Cell morphology of the normal control group was complete, with few autophagy lysosomes. Compared with the normal control group, the number of autophagic lysosomes in the mechanical injury group increased, and cell damage was more severe. Compared with the mechanical injury group, the number of autophagy lysosomes in the mechanical injury + TUDCA intervention group increased significantly, and cell damage was less severe. Further, compared with the normal control group, beclin-1 and lc3ii / I expressions in the mechanical injury group were significantly higher (P < 0.05); compared with the mechanical injury group, beclin-1 and lc3ii / I expressions in the mechanical injury + TUDCA intervention group were significantly higher (P < 0.05).. TUDCA can protect SCN from mechanical injury in vitro, which may be related to the enhancement of the expression of autophagy-related protein beclin-1 and LC3 II/I.

Topics: Animals; Autophagy; Neurons; Rats; Rats, Sprague-Dawley; Spinal Cord Injuries; Taurochenodeoxycholic Acid

Previous studies have reported the protective effects of tauroursodeoxycholic acid (TUDCA) on gastric epithelial cells in some animal models, but the precise mechanisms are unclear. This study examined the effects of TUDCA on NF-κB signaling in gastric epithelial cells. Moreover, the protective effects of TUDCA in experimental gastritis models induced by ethanol and NSAID were evaluated and compared with ursodeoxycholic acid (UDCA).. After a pretreatment with TUDCA or UDCA, human gastric epithelial MKN-45 cells were stimulated with tumor necrosis factor (TNF)-α to activate NF-κB signaling. A real-time PCR (RT-PCR) for human interleukin (IL)-1 mRNA was performed. An electrophoretic mobility shift assay (EMSA) and immunoblot analyses were carried out. In murine models, after a pretreatment with TUDCA or UDCA, ethanol and indomethacin were administered via oral gavage. Macroscopic and microscopic assessments were performed to evaluate the preventive effects of TUDCA and UDCA on murine gastritis.. A pretreatment with TUDCA downregulated the IL-1α mRNA levels in MKN-45 cells stimulated with TNF-α, as assessed by RT-PCR. As determined using EMSA, a pretreatment with TUDCA reduced the TNF-α-induced NF-κB DNA binding activity. A pretreatment with TUDCA inhibited IκBα phosphorylation induced by TNF-α, as assessed by immunoblot analysis. TUDCA attenuated the ethanol-induced and NSAID-induced gastritis in murine models, as determined macroscopically and microscopically.. TUDCA inhibited NF-κB signaling in gastric epithelial cells and ameliorated ethanol- and NSAID-induced gastritis in murine models. These results support the potential of TUDCA for the prevention of gastritis in humans.

Topics: Animals; Anti-Inflammatory Agents, Non-Steroidal; Epithelial Cells; Ethanol; Gastritis; Humans; Mice; NF-kappa B; RNA, Messenger; Taurochenodeoxycholic Acid; Tumor Necrosis Factor-alpha; Ursodeoxycholic Acid

Although the association of elevated homocysteine level with cardiac hypertrophy has been reported, the molecular mechanisms by which homocysteine induces cardiac hypertrophy remain inadequately understood. In this study we aim to uncover the roles of cyclic nucleotide phosphodiesterase 1 (PDE1) and endoplasmic reticulum (ER) stress and their relationship to advance the mechanistic understanding of homocysteine-induced cardiac cell hypertrophy. H9c2 cells and primary neonatal rat cardiomyocytes are exposed to homocysteine with or without ER stress inhibitor TUDCA or PDE1-specific inhibitor Lu AF58027, or transfected with siRNAs targeting PDE1 isoforms prior to homocysteine-exposure. Cell surface area is measured and ultrastructure is examined by transmission electron microscopy. Hypertrophic markers, PDE1 isoforms, and ER stress molecules are detected by q-PCR and western blot analysis. Intracellular cGMP and cAMP are measured by ELISA. The results show that homocysteine causes the enlargement of H9c2 cells, increases the expressions of hypertrophic markers β-MHC and ANP, upregulates PDE1A and PDE1C, promotes the expressions of ER stress molecules, and causes ER dilatation and degranulation. TUDCA and Lu AF58027 downregulate β-MHC and ANP, and alleviate cell enlargement. TUDCA decreases PDE1A and PDE1C levels. Silencing of PDE1C inhibits homocysteine-induced hypertrophy, whereas PDE1A knockdown has minor effect. Both cAMP and cGMP are decreased after homocysteine-exposure, while only cAMP is restored by Lu AF58027 and TUDCA. TUDCA and Lu AF58027 also inhibit cell enlargement, downregulate ANP, β-MHC and PDE1C, and enhance cAMP level in homocysteine-exposed primary cardiomyocytes. ER stress mediates homocysteine-induced hypertrophy of cardiac cells via upregulating PDE1C expression Cyclic nucleotide, especially cAMP, is the downstream mediator of the ER stress-PDE1C signaling axis in homocysteine-induced cell hypertrophy.

Topics: Animals; Atrial Natriuretic Factor; Cardiomegaly; Cyclic GMP; Cyclic Nucleotide Phosphodiesterases, Type 1; Endoplasmic Reticulum Stress; Enzyme Activation; Homocysteine; Myocytes, Cardiac; Phosphoric Diester Hydrolases; Rats; Taurochenodeoxycholic Acid

Exposure to crystalline silica (CS) results in a persistent pulmonary inflammatory response, which results in abnormal tissue repair and excessive matrix deposition. Due to vague pathogenesis, there is virtually no practical therapeutic approach. Here we showed the pharmacological effects of TUDCA on CS-induced pulmonary inflammation and fibrosis. It also helped a faster recovery of CS-impaired pulmonary function. Mechanistically, TUDCA suppressed interferon (IFN)-γ and interleukin (IL)-17A productions by pulmonary helper T (Th) cells. We demonstrated that CS-boosted cytokine-producing Th cells were effector memory (T

Topics: CD8-Positive T-Lymphocytes; Fibrosis; Humans; Immunologic Memory; Lung; Memory T Cells; Silicon Dioxide; Silicosis; Taurochenodeoxycholic Acid

Early childhood malnutrition may facilitate the onset of obesity and diabetes mellitus in adulthood which, when established, makes it more resistant to therapeutic interventions. The beneficial effects of tauroursodeoxycholic acid (TUDCA) in glucose homeostasis and body fat accumulation were analyzed in protein-restricted mice fed a high-fat diet (HFD). C57BL/6 mice were fed a control (14% protein [C]) or a protein-restricted (6% protein [R]) diet for 6 weeks. Afterward, mice received an HFD or not for 12 weeks (C mice fed an HFD [CH] and R mice fed an HFD [RH]). In the last 15 days of this period, half of the mice fed a HFD received i.p. PBS (groups CH and RH) or 300 mg/kg TUDCA (groups CHT and RHT). RH mice developed obesity, as demonstrated by the increase in fat accumulation, liver steatosis, and metabolic inflexibility. Additionally, showed glucose intolerance and insulin hypersecretion. TUDCA reduced adiposity and improve metabolic flexibility through increased HSL phosphorylation and CPT1 expression in eWAT and BAT, and reduced ectopic fat deposition by activating the AMPK/HSL pathway in the liver. Also, improved glucose tolerance and insulin sensitivity, normalizing insulin secretion by reducing GDH expression and increasing insulin peripheral sensitivity by greater expression of the IRβ in muscle and adipose tissue and reducing PEPCK liver expression. Our data indicate that TUDCA reduces global adiposity and improves glucose tolerance and insulin sensitivity in protein malnourished mice fed a HFD. Therefore, this is a possible strategy to reverse metabolic disorders in individuals with the double burden of malnutrition.

Topics: Adiposity; Animals; Diet, High-Fat; Glucose; Insulin; Insulin Resistance; Malnutrition; Mice; Mice, Inbred C57BL; Obesity; Taurochenodeoxycholic Acid

Central nervous system damage is an essential clinical feature that occurs in the early or late stages of syphilis infection. The abnormal enhancement of microglial phagocytosis can cause damage to the nervous system. However, the contribution of abnormally enhanced microglial phagocytosis to the pathogenesis of Treponema pallidum subsp. pallidum (T. pallidum) infection remains unknown.. In this study, we sought to determine the role of recombinant T. pallidum Tp47 in promoting microglia phagocytosis and its associated mechanisms.. Microglial HMC3 cells were used to investigate the effect of the Tp47 on phagocytosis and the roles of autophagy and endoplasmic reticulum stress in Tp47-induced phagocytosis.. HMC3 cells exhibited obvious phagocytosis when stimulated with Tp47. The levels of P62 degradation, Beclin1 expression and the LC3II/LC3I ratio were significantly elevated, and the fusion of autophagosomes and lysosomes was promoted in Tp47-stimulated HMC3 cells. Treatment with the autophagy inhibitors 3-MA and Baf A1 inhibited Tp47-induced phagocytosis. Meanwhile, the endoplasmic reticulum stress markers PERK, IRE1α, GRP78, ATF4 and XBP1s were upregulated in Tp47-stimulated HMC3 cells. In addition, we found that TUDCA could inhibit Tp47-induced expression of IRE1α but not PERK or ATF4. 4-PBA inhibited TP47-induced PERK and ATF4 protein expression but did not inhibit IRE1α expression. Attenuation of endoplasmic reticulum stress by administration of TUDCA and 4-PBA abrogated Tp47-mediated autophagy.. These results suggested that Tp47 activated autophagy through two key pathways associated with endoplasmic reticulum stress, PERK/ATF4 and IRE1/XBP1, to promote phagocytosis in HMC3 cells. These findings provided a basis for the understanding of the pathophysiology of neurological disorders that occur during the course of syphilis.

Topics: Autophagy; Bacterial Proteins; Beclin-1; Butylamines; Endoplasmic Reticulum Stress; Endoribonucleases; Humans; Phagocytosis; Protein Serine-Threonine Kinases; Syphilis; Taurochenodeoxycholic Acid; Treponema pallidum

C. difficile infection (CDI) is a highly inflammatory disease mediated by the production of two large toxins that weaken the intestinal epithelium and cause extensive colonic tissue damage. Antibiotic alternative therapies for CDI are urgently needed as current antibiotic regimens prolong the perturbation of the microbiota and lead to high disease recurrence rates. Inflammation is more closely correlated with CDI severity than bacterial burden, thus therapies that target the host response represent a promising yet unexplored strategy for treating CDI. Intestinal bile acids are key regulators of gut physiology that exert cytoprotective roles in cellular stress, inflammation, and barrier integrity, yet the dynamics between bile acids and host cellular processes during CDI have not been investigated. Here we show that several bile acids are protective against apoptosis caused by C. difficile toxins in Caco-2 cells and that protection is dependent on conjugation of bile acids. Out of 20 tested bile acids, taurine conjugated ursodeoxycholic acid (TUDCA) was the most potent inhibitor, yet unconjugated UDCA did not alter toxin-induced apoptosis. TUDCA treatment decreased expression of genes in lysosome associated and cytokine signaling pathways. TUDCA did not affect C. difficile growth or toxin activity

Topics: Anti-Bacterial Agents; Antibodies, Bacterial; Apoptosis; Bile Acids and Salts; Caco-2 Cells; Clostridioides difficile; Clostridium Infections; Humans; Inflammation; Taurochenodeoxycholic Acid; Ursodeoxycholic Acid

Bile acid tauroursodeoxycholic (TUDCA), formed from the association of ursodeoxycholic acid (UDCA) with taurine, has already been shown to increase mitochondrial biogenesis and cell survival, in addition to reduce reticulum stress markers in different cell types. However, its mechanism of action upon insulin secretion control in obesity is still unknown. In this sense, we seek to clarify whether taurine, associated with bile acid, could improve the function of the pancreatic β-cells exposed to fatty acids through the regulation of mitochondrial metabolism. To test this idea, insulin-producing cells (INS1-E) were exposed to a fatty acid mix containing 500 μM of each palmitate and oleate for 48 hours treated or not with 300 μM of TUDCA. After that, glucose-stimulated insulin secretion and markers of mitochondrial metabolism were evaluated. Our results showed that the fatty acid mix was efficient in inducing hyperfunction of INS1-E cells as observed by the increase in insulin secretion, protein expression of citrate synthase, and mitochondrial density, without altering cell viability. The treatment with TUDCA normalized insulin secretion, reducing the protein expression of citrate synthase, mitochondrial mass, and the mitochondrial membrane potential. This effect was associated with a decrease in the generation of mitochondrial superoxide and c-Jun N-terminal kinase (JNK) protein content. The findings are also consistent with the hypothesis that TUDCA normalizes insulin secretion by improving mitochondrial metabolism and redox balance. Thus, it highlights likely mechanisms of the action of this bile acid on the glycemic homeostasis reestablishment in obesity.

Topics: Bile Acids and Salts; Citrate (si)-Synthase; Fatty Acids; Humans; Insulin; Insulin Secretion; Insulin-Secreting Cells; Obesity; Taurine; Taurochenodeoxycholic Acid

ALS is a rapidly progressive, fatal disorder caused by motor neuron degeneration, for which there is a great unmet therapeutic need. AMX0035, a combination of sodium phenylbutyrate (PB) and taurursodiol (TUDCA, TURSO), has shown promising results in early ALS clinical trials, but its mechanisms of action remain to be elucidated. Therefore, our goal was to obtain an unbiased landscape of the molecular effects of AMX0035 in ALS patient-derived cells.. We investigated the transcriptomic and metabolomic profiles of primary skin fibroblasts from sporadic ALS patients and healthy controls (n = 12/group) treated with PB, TUDCA, or PB-TUDCA combination (Combo). Data were evaluated with multiple approaches including differential gene expression and metabolite abundance, Gene Ontology and metabolic pathway analysis, weighted gene co-expression correlation analysis (WGCNA), and combined multiomics integrated analysis.. Combo changed many more genes and metabolites than either PB or TUDCA individually. Most changes were unique to Combo and affected the expression of genes involved in nucleocytoplasmic transport, unfolded protein response, mitochondrial function, RNA metabolism, and innate immunity. WGCNA showed significant correlations between ALS gene expression modules and clinical parameters that were abolished by Combo treatment.. This study is the first to explore the molecular effects of Combo in ALS patient-derived cells. It shows that Combo has a greater and distinct impact compared with the individual compounds and provides clues to drug targets and mechanisms of action, which may underlie the benefits of this investigational drug combination.

Topics: Amyotrophic Lateral Sclerosis; Drugs, Investigational; Fibroblasts; Humans; RNA; Taurochenodeoxycholic Acid

Bile acids (BAs) are complex and incompletely understood enterohepatic-derived hormones that control whole-body metabolism. Here, we profiled postprandial BAs in the liver, feces, and plasma of 360 chow- or high-fat-diet-fed BXD male mice and demonstrated that both genetics and diet strongly influence BA abundance, composition, and correlation with metabolic traits. Through an integrated systems approach, we mapped hundreds of quantitative trait loci that modulate BAs and identified both known and unknown regulators of BA homeostasis. In particular, we discovered carboxylesterase 1c (Ces1c) as a genetic determinant of plasma tauroursodeoxycholic acid (TUDCA), a BA species with established disease-preventing actions. The association between Ces1c and plasma TUDCA was validated using data from independent mouse cohorts and a Ces1c knockout mouse model. Collectively, our data are a unique resource to dissect the physiological importance of BAs as determinants of metabolic traits, as underscored by the identification of CES1C as a master regulator of plasma TUDCA levels.

Topics: Animals; Bile Acids and Salts; Carboxylic Ester Hydrolases; Diet, High-Fat; Homeostasis; Hormones; Liver; Male; Mice; Systems Analysis; Taurochenodeoxycholic Acid

It has been reported that aging-generated gut microecosystem may promote host hepatic lipid dysmetabolism through shaping the pattern of secondary bile acids (BAs). Then as an oral drug, melatonin (Mel)-mediated beneficial efforts on the communication between gut microbiota and aging host are still not clearly. Here, we show that aging significantly shapes the pattern of gut microbiota and BAs, whereas Mel treatment reverses these phenotypes (P < 0.05), which is identified to depend on the existence of gut microbiota. Mechanistically, aging-triggered high-level expression of ileac farnesoid X receptor (FXR) is significantly decreased through Mel-mediated inhibition on Campylobacter jejuni (C. jejuni)-induced deconjugation of tauroursodeoxycholic acid (TUDCA) and glycoursodeoxycholic acid (GUDCA) (P < 0.05). The aging-induced high-level of serum taurine chenodeoxycholic acid (TCDCA) activate trimethylamine-N-oxide (TMAO)-triggered activating transcriptional factor 4 (ATF4) signaling via hepatic FXR, which further regulates hepatic BAs metabolism, whereas TUDCA inhibits aging-triggered high-level of hepatic ATF4. Overall, Mel reduces C. jejuni-mediated deconjugation of TUDCA to inhibit aging-triggered high-level expression of hepatic FXR, which further decreases hepatic TMAO production, to relieve hepatic lipid dysmetabolism.

Topics: Bile Acids and Salts; Gastrointestinal Microbiome; Lipids; Liver; Melatonin; Methylamines; Oxides; Receptors, Cytoplasmic and Nuclear; Taurochenodeoxycholic Acid

Inflammation is the main cause of corneal and retinal damage in an ocular alkali burn (OAB). The aim of this study was to investigate the effect of tauroursodeoxycholic acid (TUDCA) on ocular inflammation in a mouse model of an OAB. An OAB was induced in C57BL/6j mouse corneas by using 1 M NaOH. TUDCA (400 mg/kg) or PBS was injected intraperitoneally (IP) once a day for 3 days prior to establishing the OAB model. A single injection of Infliximab (6.25 mg/kg) was administered IP immediately after the OAB. The TUDCA suppressed the infiltration of the CD45-positive cells and decreased the mRNA and protein levels of the upregulated TNF-α and IL-1β in the cornea and retina of the OAB. Furthermore, the TUDCA treatment inhibited the retinal glial activation after an OAB. The TUDCA treatment not only ameliorated CNV and promoted corneal re-epithelization but also attenuated the RGC apoptosis and preserved the retinal structure after the OAB. Finally, the TUDCA reduced the expression of the endoplasmic reticulum (ER) stress molecules, IRE1, GRP78 and CHOP, in the retinal tissues of the OAB mice. The present study demonstrated that the TUDCA inhibits ocular inflammation and protects the cornea and retina from injury in an OAB mouse model. These results provide a potential therapeutic intervention for the treatment of an OAB.

Topics: Animals; Apoptosis; Burns, Chemical; Disease Models, Animal; Endoplasmic Reticulum Stress; Inflammation; Infliximab; Mice; Mice, Inbred C57BL; Protein Serine-Threonine Kinases; RNA, Messenger; Sodium Hydroxide; Taurochenodeoxycholic Acid; Tumor Necrosis Factor-alpha

Aging is associated with glucose metabolism disturbances, such as insulin resistance and hyperinsulinemia, which contribute to the increased prevalence of type 2 diabetes (T2D) and its complications in the elderly population. In this sense, some bile acids have emerged as new therapeutic targets to treat TD2, as well as associated metabolic disorders. The taurine conjugated bile acid, tauroursodeoxycholic acid (TUDCA) improves glucose homeostasis in T2D, obesity, and Alzheimer's disease mice model. However, its effects in aged mice have not been explored yet. Here, we evaluated the actions of TUDCA upon glucose-insulin homeostasis in aged C57BL/6 male mice (18-month-old) treated with 300 mg/kg of TUDCA or its vehicle. TUDCA attenuated hyperinsulinemia and improved glucose homeostasis in aged mice, by enhancing liver insulin-degrading enzyme (IDE) expression and insulin clearance. Furthermore, the improvement in glucose-insulin homeostasis in these mice was accompanied by a reduction in adiposity, associated with adipocyte hypertrophy, and lipids accumulation in the liver. TUDCA-treated aged mice also displayed increased energy expenditure and metabolic flexibility, as well as a better cognitive ability. Taken together, our data highlight TUDCA as an interesting target for the attenuation of age-related hyperinsulinemia and its deleterious effects on metabolism.

Topics: Aged; Animals; Bile Acids and Salts; Diabetes Mellitus, Type 2; Glucose; Humans; Hyperinsulinism; Insulin; Male; Mice; Mice, Inbred C57BL; Obesity; Taurochenodeoxycholic Acid

Parkinson's disease (PD) is a progressive motor disease of unknown etiology. Although neuroprotective ability of endogenous bile acid, tauroursodeoxycholic acid (TUDCA), shown in various diseases, including an acute model of PD,the potential therapeutic role of TUDCA in progressive models of PD that exhibit all aspects of PD has not been elucidated. In the present study, mice were assigned to one of four treatment groups: (1) Probenecid (PROB); (2) TUDCA, (3) MPTP + PROB (MPTPp); and (3) TUDCA + MPTPp.

Topics: Animals; Disease Models, Animal; Dopamine; Dopaminergic Neurons; Humans; Mice; Mice, Inbred C57BL; Neuroprotective Agents; Parkinson Disease; Taurochenodeoxycholic Acid

Alzheimer's disease (AD) is a progressive neurodegenerative disorder and the most common cause of dementia. While cognitive deficits remain the major manifestation of AD, metabolic and non-cognitive abnormalities, such as alterations in food intake, body weight and energy balance are also present, both in AD patients and animal models. In this sense, the tauroursodeoxycholic acid (TUDCA) has shown beneficial effects both in reducing the central and cognitive markers of AD, as well as in attenuating the metabolic disorders associated with it. We previously demonstrated that TUDCA improves glucose homeostasis and decreases the main AD neuromarkers in the streptozotocin-induced AD mouse model (Stz). Besides that, TUDCA-treated Stz mice showed lower body weight and adiposity. Here, we investigated the actions of TUDCA involved in the regulation of body weight and adiposity in Stz mice, since the effects of TUDCA in hypothalamic appetite control and energy homeostasis have not yet been explored in an AD mice model. The TUDCA-treated mice (Stz + TUDCA) displayed lower food intake, higher energy expenditure (EE) and respiratory quotient. In addition, we observed in the hypothalamus of the Stz + TUDCA mice reduced fluorescence and gene expression of inflammatory markers, as well as normalization of the orexigenic neuropeptides AgRP and NPY expression. Moreover, leptin-induced p-JAK2 and p-STAT3 signaling in the hypothalamus of Stz + TUDCA mice was improved, accompanied by reduced acute food intake after leptin stimulation. Taken together, we demonstrate that TUDCA treatment restores energy metabolism in Stz mice, a phenomenon that is associated with reduced food intake, increased EE and improved hypothalamic leptin signaling. These findings suggest treatment with TUDCA as a promising therapeutic intervention for the control of energy homeostasis in AD individuals.

Topics: Adiposity; Alzheimer Disease; Animals; Biomarkers; Body Weight; Disease Management; Disease Models, Animal; Energy Metabolism; Gene Expression; Homeostasis; Immunohistochemistry; Inflammation Mediators; Leptin; Male; Mice; Organ Specificity; Signal Transduction; Streptozocin; Taurochenodeoxycholic Acid; Thermogenesis

Tauroursodeoxycholic acid (TUDCA) is a hydrophilic bile acid derivative, which has been demonstrated to have neuroprotective effects in different neurological disease models. However, the effect and underlying mechanism of TUDCA on spinal cord injury (SCI) have not been fully elucidated. This study aims to investigate the protective effects of TUDCA in the SCI mouse model and the related mechanism involved.. We found that TUDCA attenuated axon degeneration induced by H. TUDCA treatment can alleviate secondary injury and promote functional recovery by reducing oxidative stress, inflammatory response, and apoptosis induced by primary injury, and promote axon regeneration and remyelination, which could be used as a potential therapy for human SCI recovery.

Topics: Animals; Apoptosis; Disease Models, Animal; Inflammation; Mice; Mice, Inbred C57BL; Nerve Degeneration; Nerve Regeneration; Neuroprotective Agents; Oxidative Stress; Recovery of Function; Spinal Cord Injuries; Taurochenodeoxycholic Acid

Obesity and diabetes are well-established risk factors of Alzheimer's disease (AD). In the brains of patients with AD and model mice, diabetes-related factors have been implicated in the pathological changes of AD. However, the molecular mechanistic link between the peripheral metabolic state and AD pathophysiology have remained elusive. Endoplasmic reticulum (ER) stress is known as one of the major contributors to the metabolic abnormalities in obesity and diabetes. Interventions aimed at reducing ER stress have been shown to improve the systemic metabolic abnormalities, although their effects on the AD pathology have not been extensively studied.. We examined whether interventions targeting ER stress attenuate the obesity/diabetes-induced Aβ accumulation in brains. We also aimed to determine whether ER stress that took place in the peripheral tissues or central nervous system was more important in the Aβ neuropathology. Furthermore, we explored if age-related metabolic abnormalities and Aβ accumulation could be suppressed by reducing ER stress.. APP transgenic mice (A7-Tg), which exhibit Aβ accumulation in the brain, were used as a model of AD to analyze parameters of peripheral metabolic state, ER stress, and Aβ pathology in the brain. Intraperitoneal or intracerebroventricular administration of taurodeoxycholic acid (TUDCA), a chemical chaperone, was performed in high-fat diet (HFD)-fed A7-Tg mice for ~1 month, followed by analyses at 9 months of age. Mice fed a normal diet were treated with TUDCA by drinking water for 4 months and intraperitoneally for 1 month in parallel, and analyzed at 15 months of age.. Intraperitoneal administration of TUDCA suppressed ER stress in the peripheral tissues and ameliorated the HFD-induced obesity and insulin resistance. Concomitantly, Aβ levels in the brain were significantly reduced. In contrast, intracerebroventricular administration of TUDCA had no effect on the Aβ levels. Peripheral administration of TUDCA was also effective against the age-related obesity and insulin resistance, and markedly reduced amyloid accumulation.. Interventions that target peripheral ER stress might be beneficial therapeutic and prevention strategies against brain Aβ pathology associated with metabolic overload and aging.

Topics: Alzheimer Disease; Amyloid beta-Peptides; Animals; Antiviral Agents; Brain; Diet; Disease Models, Animal; Endoplasmic Reticulum Stress; Humans; Infusions, Intraventricular; Injections, Intraperitoneal; Mice; Mice, Transgenic; Taurochenodeoxycholic Acid

Steatosis is a liver lesion reported with numerous pharmaceuticals. Prior studies showed that severe impairment of mitochondrial fatty acid oxidation (mtFAO) constantly leads to lipid accretion in liver. However, much less is known about the mechanism(s) of drug-induced steatosis in the absence of severe mitochondrial dysfunction, although previous studies suggested the involvement of mild-to-moderate inhibition of mtFAO, increased de novo lipogenesis (DNL), and impairment of very low-density lipoprotein (VLDL) secretion. The objective of our study, mainly carried out in human hepatoma HepaRG cells, was to investigate these 3 mechanisms with 12 drugs able to induce steatosis in human: amiodarone (AMIO, used as positive control), allopurinol (ALLO), D-penicillamine (DPEN), 5-fluorouracil (5FU), indinavir (INDI), indomethacin (INDO), methimazole (METHI), methotrexate (METHO), nifedipine (NIF), rifampicin (RIF), sulindac (SUL), and troglitazone (TRO). Hepatic cells were exposed to drugs for 4 days with concentrations decreasing ATP level by less than 30% as compared to control and not exceeding 100 × C

Topics: Apolipoproteins B; Biomarkers; Cell Line, Tumor; Endoplasmic Reticulum Stress; Fatty Acids; Fatty Liver; Gene Expression Regulation; Hepatocytes; Humans; Lipogenesis; Lipoproteins, VLDL; Mitochondria, Liver; Oxidation-Reduction; RNA, Messenger; Taurochenodeoxycholic Acid; Toxicity Tests

Alzheimer's disease (AD) is a neurodegenerative disorder and the major cause of dementia. According to predictions of the World Health Organization, more than 150 million people worldwide will suffer from dementia by 2050. An increasing number of studies have associated AD with type 2 diabetes mellitus (T2DM), since most of the features found in T2DM are also observed in AD, such as insulin resistance and glucose intolerance. In this sense, some bile acids have emerged as new therapeutic targets to treat AD and metabolic disorders. The taurine conjugated bile acid, tauroursodeoxycholic (TUDCA), reduces amyloid oligomer accumulation and improves cognition in APP/PS1 mice model of AD, and also improves glucose-insulin homeostasis in obese and type 2 diabetic mice. Herein, we investigated the effect of TUDCA upon glucose metabolism in streptozotocin-induced AD mice model (Stz). The Stz mice that received 300 mg/kg TUDCA during 10 days (Stz + TUDCA), showed improvement in glucose tolerance and insulin sensitivity, reduced fasted and fed glycemia, increased islet mass and β-cell area, as well as increased glucose-stimulated insulin secretion, compared with Stz mice that received only PBS. Stz + TUDCA mice also displayed lower neuroinflammation, reduced protein content of amyloid oligomer in the hippocampus, improved memory test and increased protein content of insulin receptor β-subunit in the hippocampus. In conclusion, TUDCA treatment enhanced glucose homeostasis in the streptozotocin-induced Alzheimer's disease mice model, pointing this bile acid as a good strategy to counteract glucose homeostasis disturbance in AD pathology.

Topics: Alzheimer Disease; Amyloid beta-Peptides; Animals; Bile Acids and Salts; Blood Glucose; Cytokines; Disease Models, Animal; Glucose; Hippocampus; Inflammation; Insulin; Insulin-Secreting Cells; Male; Memory and Learning Tests; Mice; Mice, Inbred C57BL; Real-Time Polymerase Chain Reaction; Streptozocin; Taurochenodeoxycholic Acid

Topics: Amyotrophic Lateral Sclerosis; Clinical Trials as Topic; Drug Combinations; Humans; Oligonucleotides; Phenylbutyrates; Superoxide Dismutase-1; Taurochenodeoxycholic Acid

Alcoholic liver disease (ALD) occurs as a result of chronic and excessive alcohol consumption. It encompasses a wide spectrum of chronic liver abnormalities that range from steatosis to alcoholic hepatitis, progressive fibrosis and cirrhosis. Endoplasmic reticulum (ER) stress induced by ethanol metabolism in hepatocytes has been established as an important contributor to the pathogenesis of ALD. However, whether SIRT6 exerts regulatory effects on ethanol-induced ER stress and contributes to the pathogenesis of ALD is unclear. In this study, we developed and characterized Sirt6 hepatocyte-specific knockout and transgenic mouse models that were treated with chronic-plus-binge ethanol feeding. We observed that hepatic Sirt6 deficiency led to exacerbated ethanol-induced liver injury and aggravated hepatic ER stress. Tauroursodeoxycholic acid (TUDCA) treatment remarkably attenuated ethanol-induced ER stress and ameliorated ALD pathologies caused by Sirt6 ablation. Reciprocally, SIRT6 hepatocyte-specific transgenic mice exhibited reduced ER stress and ameliorated liver injury caused by ethanol exposure. Consistently, knockdown of Sirt6 elevated the expression of ER stress related genes in primary hepatocytes treated with ethanol, whereas overexpression of SIRT6 reduced their expression, indicating SIRT6 regulates ethanol-induced hepatic ER stress in a cell autonomous manner. Collectively, our results suggest that SIRT6 is a positive regulator of ethanol-induced ER stress in the liver and protects against ALD by relieving ER stress.

Topics: Animals; Cells, Cultured; Central Nervous System Depressants; Chemical and Drug Induced Liver Injury, Chronic; Cholagogues and Choleretics; Disease Models, Animal; Endoplasmic Reticulum Stress; Ethanol; Hepatocytes; Male; Mice; Mice, Knockout; Mice, Transgenic; Sirtuins; Taurochenodeoxycholic Acid

Endoplasmic reticulum (ER) stress is closely associated with various metabolic diseases, such as obesity and diabetes. Development of beige/brite adipocytes increases thermogenesis and helps to reduce obesity. Although the relationship between ER stress and white adipocytes has been studied considerably, the possible role of ER stress and the unfolded protein response (UPR) induction in beige adipocytes differentiation remain to be investigated. In this study we investigated how ER stress affected beige adipocytes differentiation both in vitro and in vivo. Phosphorylation of eIF2α was transiently decreased in the early phase (day 2), whereas it was induced at the late phase with concomitant induction of C/EBP homologous protein (CHOP) during beige adipocytes differentiation. Forced expression of CHOP inhibited the expression of beige adipocytes markers, including Ucp1, Cox8b, Cidea, Prdm16, and Pgc-1α, following the induction of beige adipocytes differentiation. When ER stress was reduced by the chemical chaperone tauroursodeoxycholic acid (TUDCA), the expression of the beige adipocytes marker uncoupling protein 1 (UCP1) was significantly enhanced in inguinal white adipose tissue (iWAT) and high fat diet (HFD)-induced abnormal metabolic phenotype was improved. In summary, we found that ER stress and the UPR induction were closely involved in beige adipogenesis. These results suggest that modulating ER stress could be a potential therapeutic intervention against metabolic dysfunctions via activation of iWAT browning.

Topics: Adipocytes, Beige; Adipogenesis; Animals; Cell Differentiation; Diet, High-Fat; Endoplasmic Reticulum Stress; Male; Metabolic Syndrome; Mice; Mice, Inbred C57BL; Obesity; Phenotype; Signal Transduction; Taurochenodeoxycholic Acid; Thermogenesis; Unfolded Protein Response

Osteoarthritis (OA) is considered one of the most common arthritic diseases characterized by progressive degradation and abnormal remodeling of articular cartilage. Potential therapeutics for OA aim at restoring proper chondrocyte functioning and inhibiting apoptosis. Previous studies have demonstrated that tauroursodeoxycholic acid (TUDCA) showed anti-inflammatory and anti-apoptotic activity in many models of various diseases, acting mainly via alleviation of endoplasmic reticulum (ER) stress. However, little is known about cytoprotective effects of TUDCA on chondrocyte cells. The present study was designed to evaluate potential effects of TUDCA on interleukin-1β (IL-1β) and tunicamycin (TNC)-stimulated NHAC-kn chondrocytes cultured in normoxic and hypoxic conditions. Our results showed that TUDCA alleviated ER stress in TNC-treated chondrocytes, as demonstrated by reduced CHOP expression; however, it was not effective enough to prevent apoptosis of NHAC-kn cells in either normoxia nor hypoxia. However, co-treatment with TUDCA alleviated inflammatory response induced by IL-1β, as shown by down regulation of

Topics: Anti-Inflammatory Agents; Apoptosis; Cartilage, Articular; Cell Hypoxia; Cells, Cultured; Chondrocytes; Endoplasmic Reticulum; Endoplasmic Reticulum Stress; Humans; Inflammation; Interleukin-1beta; Osteoarthritis; Taurochenodeoxycholic Acid; Transcription Factor CHOP; Tunicamycin

Topics: Animals; Calcium-Calmodulin-Dependent Protein Kinase Type 2; Central Nervous System Stimulants; Cyclin-Dependent Kinase 5; Endoplasmic Reticulum Stress; Hippocampus; Long-Term Potentiation; Male; Memory; Methamphetamine; Mice, Inbred C57BL; Neuronal Plasticity; Signal Transduction; Taurochenodeoxycholic Acid

Mutations in human equilibrative nucleoside transporter 3 (ENT3) encoded by SLC29A3 results in anemia and erythroid hypoplasia, suggesting that ENT3 may regulate erythropoiesis. Here, we demonstrate that lysosomal ENT3 transport of taurine-conjugated bile acids (TBA) facilitates TBA chemical chaperone function and alleviates endoplasmic reticulum (ER) stress in expanding mouse hematopoietic stem and progenitor cells (HSPCs). Slc29a3

Topics: Animals; Apoptosis; Bile Acids and Salts; Biological Transport; Bone Marrow Cells; Cell Differentiation; Cell Survival; Endoplasmic Reticulum; Endoplasmic Reticulum Stress; Erythroid Cells; Hematopoietic Stem Cell Transplantation; Hematopoietic Stem Cells; Hydrogen-Ion Concentration; Lysosomes; Metabolomics; Mice; Nucleoside Transport Proteins; Taurine; Taurochenodeoxycholic Acid

Retinitis pigmentosa (RP) is a group of genetically diverse inherited disorders characterised by the progressive photoreceptors and pigment epithelial cell dysfunction leading to central vision impairment. Although important advances in the understanding of the pathophysiologic pathways involved in RP have been made, drug delivery for the treatment of ocular disorders affecting the posterior segment of the eye is still an unmet clinical need. In the present study, we describe the development of multi-loaded PLGA-microspheres (MSs) incorporating two neuroprotectants agents (glial cell-line-derived neurotrophic factor-GDNF and Tauroursodeoxycholic acid-TUDCA) as a potential therapeutic tool for the treatment of RP. A solid-in-oil-in-water (S/O/W) emulsion solvent extraction-evaporation technique was employed for MS preparation. A combination of PLGA and vitamin E was used to create the microcarriers. The morphology, particle size, encapsulation efficiency and in vitro release profile of the MSs were studied. Encapsulation efficiencies of GDNF and TUDCA for the initial multiloaded MSs, prepared with methylene chloride (MC) as organic solvent and polyvinyl alcohol (PVA) solution in the external phase, were 28.53±0.36% and 45.65±8.01% respectively. Different technological parameters to optimise the formulation such as the incorporation of a water-soluble co-solvent ethanol (EtOH) in the internal organic phase, as well as NaCl concentration, and viscosity using a viscosizing agent (hydroxypropyl methylcellulose-HPMC) in the external aqueous phase were considered. EtOH incorporation and external phase viscosity of the emulsion were critical attributes for improving drug loading of both compounds. In such a way, when using a methylene chloride/EtOH ratio 75:25 into the inner organic phase and the viscosity agent HPMC (1% w/v) in the external aqueous phase, GDNF and TUDCA payloads resulted 48.86±1.49% and 78.58±10.40% respectively, and a decrease in the initial release of GDNF was observed (22.03±1.41% compared with 40.86±6.66% of the initial multi-loaded formulation). These optimised microparticles exhibited sustained in vitro releases over 91 days. These results suggest that the microencapsulation procedure optimised in this work presents a promising technological strategy for the development of multi-loaded intraocular drug delivery systems (IODDS).

Topics: Emulsions; Glial Cell Line-Derived Neurotrophic Factor; Humans; Lactic Acid; Microspheres; Particle Size; Polyglycolic Acid; Polylactic Acid-Polyglycolic Acid Copolymer; Retinal Diseases; Taurochenodeoxycholic Acid

Long-term exposure to crystalline silica (CS) results in silicosis, which is characterized by progressive pulmonary fibrosis. The endoplasmic reticulum (ER) plays a critical role in protein processing, and the accumulation of unfolded proteins triggered by external stimuli often leads to ER stress. In the present study, we found that inhibition of ER stress alleviated CS-induced pulmonary fibrosis. Moreover, we observed that TXNDC5, a resident ER protein, was involved in the activation of fibroblasts. Mechanistically, we explored the relationship between ER stress and TXNDC5 and demonstrated that IRE1α-XBP-1 signaling was closely related to TXNDC5. Pharmacological inhibition of IRE1α endoribonuclease activity, in addition to knockdown of Xbp1 expression, reduced TXNDC5 expression in activated fibroblasts. Furthermore, pharmacological inhibition of IRE1α in vivo ameliorated pulmonary function and delayed CS-induced lung fibrosis. In conclusion, the present study illuminates the role of ER stress-related IRE1α-TXNDC5 signaling in fibroblast activation and its effects on CS-induced pulmonary fibrogenesis, which may provide novel targets for silicosis therapy.

Topics: Animals; Cytokines; Endoplasmic Reticulum Stress; Endoribonucleases; Lung; Male; Mice; Mice, Inbred C57BL; NIH 3T3 Cells; Protein Serine-Threonine Kinases; Pulmonary Fibrosis; Silicon Dioxide; Taurochenodeoxycholic Acid; Thioredoxins; Up-Regulation

N. We first conducted transcriptome-wide m. We identified an overwhelming proportion of m. We demonstrate the essential role of Mettl14 in facilitating liver regeneration by modulating polypeptide-processing proteins in the ER in an m

Topics: Adenosine; Animals; Apoptosis; Cell Proliferation; Endoplasmic Reticulum; Endoplasmic Reticulum Stress; Gene Deletion; Hepatectomy; Hepatocytes; Homeostasis; Liver; Liver Regeneration; Male; Methyltransferases; Mice, Knockout; Necrosis; Organ Specificity; Peptides; RNA Stability; RNA, Messenger; Taurochenodeoxycholic Acid; Transcriptome

Conditions of impaired energy and nutrient homeostasis, such as diabetes and obesity, are associated with infertility. Hyperglycemia increases endoplasmic reticulum stress as well as oxidative stress and reduces embryo development and quality. Oxidative stress also causes deoxyribonucleic acid damage, which impairs embryo quality and development. The natural bile acid tauroursodeoxycholic acid reduces endoplasmic reticulum stress and rescues developmentally incompetent late-cleaving embryos, as well as embryos subjected to nuclear stress, suggesting the endoplasmic reticulum stress response, or unfolded protein response, and the genome damage response are linked. Tauroursodeoxycholic acid acts via the Takeda-G-protein-receptor-5 to alleviate nuclear stress in embryos. To evaluate the role of tauroursodeoxycholic acid/Takeda-G-protein-receptor-5 signaling in embryo unfolded protein response, we used a model of glucose-induced endoplasmic reticulum stress. Embryo development was impaired by direct injection of tauroursodeoxycholic acid into parthenogenetically activated oocytes, whereas it was improved when tauroursodeoxycholic acid was added to the culture medium. Attenuation of the Takeda-G-protein-receptor-5 precluded the positive effect of tauroursodeoxycholic acid supplementation on development of parthenogenetically activated and fertilized embryos cultured under standard conditions and parthenogenetically activated embryos cultured with excess glucose. Moreover, attenuation of tauroursodeoxycholic acid/Takeda-G-protein-receptor-5 signaling induced endoplasmic reticulum stress, oxidative stress and cell survival genes, but decreased expression of pluripotency genes in parthenogenetically activated embryos cultured under excess glucose conditions. These data suggest that Takeda-G-protein-receptor-5 signaling pathways link the unfolded protein response and genome damage response. Furthermore, this study identifies Takeda-G-protein-receptor-5 signaling as a potential target for mitigating fertility issues caused by nutrient excess-associated blastomere stress and embryo death.

Topics: Animals; Blastomeres; Cholagogues and Choleretics; Embryo, Mammalian; Embryonic Development; Endoplasmic Reticulum Stress; Glucose; Oxidative Stress; Receptors, G-Protein-Coupled; Sus scrofa; Taurochenodeoxycholic Acid; Unfolded Protein Response

Probiotics, including Lactobacillus rhamnosus GG ATCC53103 and Lactobacillus plantarum JL01, can improve growth performance and immunity of piglets, and relieve weaning stress-related immune disorders such as intestinal infections and inflammation. This study aimed to evaluate the ability of co-administration of the probiotics L. rhamnosus GG ATCC53103 and L. plantarum JL01 to stimulate immune responses and improve gut health during the critical weaning period in piglets. Forty-eight weaned piglets were randomly divided into four groups, and fed daily for 28 days either without, or with the two probiotics independently, or in combination. On day 28, we analyzed the cytokine and bacterial changes in intestinal mucosa and the hepatic portal vein blood metabolites of the weaned piglets. Our results showed that combined L. rhamnosus GG ATCC53103 and L. plantarum JL01 significantly increased (p < 0.05) the growth performance and expression of IL-10 and TGF-β1 mRNAs. In contrast, this treatment significantly decreased (p < 0.05) IL-1β mRNA level in the jejunum, ileum, and cecum. Furthermore, the secretion of IL-6 in the cecum, IL-1β in the jejunum, ileum, and cecum, and TNF-α in the jejunum and ileum was significantly decreased (p < 0.05). The relative abundance of Prevotella_9 and Enterococcus in ileum and cecum was significantly increased (p < 0.05). The relative abundance of Ruminococcus_1 and Ruminococcaceae_UCG-005 in cecum was significantly decreased (p < 0.05). Prevotella_9 and Enterococcus may increase the accumulation of (4Z,7Z,10Z,13Z,16Z,19Z)-4,7,10,13,16,19-docosahexaenoic acid (DHA) and tauroursodeoxycholic acid (TCDA) in portal vein blood, while Ruminococcus_1 and Ruminococcaceae_UCG-005 may decrease the accumulation of succinic and palmitic acids. These results indicate that L. rhamnosus GG ATCC53103 and L. plantarum JL01 may regulate cytokine levels by reducing the accumulation of succinic and palmitic acids and increasing the accumulation of TCDA and DHA, thereby enhancing the immunity of weaned piglets.

Topics: Animals; Cytokines; Docosahexaenoic Acids; Gene Expression Regulation; Intestinal Mucosa; Lacticaseibacillus rhamnosus; Lactobacillus plantarum; Palmitic Acids; Probiotics; Random Allocation; Succinic Acid; Swine; Taurochenodeoxycholic Acid; Weaning

Burkholderia pseudomallei, a facultative intracellular bacterium, is the aetiological agent of melioidosis that is responsible for up to 40% sepsis-related mortality in epidemic areas. However, no effective vaccine is available currently, and the drug resistance is also a major problem in the treatment of melioidosis. Therefore, finding new clinical treatment strategies in melioidosis is extremely urgent.. We demonstrated that tauroursodeoxycholic acid (TUDCA), a clinically available endoplasmic reticulum (ER) stress inhibitor, can promote B. pseudomallei clearance both in vivo and in vitro. In this study, we investigated the effects of TUDCA on the survival of melioidosis mice, and found that treatment with TUDCA significantly decreased intracellular survival of B. pseudomallei. Mechanistically, we found that B. pseudomallei induced apoptosis and activated IRE1 and PERK signaling ways of ER stress in RAW264.7 macrophages. TUDCA treatment could reduce B. pseudomallei-induced ER stress in vitro, and TUDCA is protective in vivo.. Taken together, our study has demonstrated that B. pseudomallei infection results in ER stress-induced apoptosis, and TUDCA enhances the clearance of B. pseudomallei by inhibiting ER stress-induced apoptosis both in vivo and in vitro, suggesting that TUDCA could be used as a potentially alternative treatment for melioidosis.

Topics: Animals; Apoptosis; Burkholderia pseudomallei; Cell Line; Endoplasmic Reticulum Stress; Melioidosis; Mice; Signal Transduction; Survival Analysis; Taurochenodeoxycholic Acid

Several studies demonstrate that endoplasmic reticulum (ER) stress-mediated epithelial-mesenchymal transition (EMT) is involved in the process of bleomycin (BLM)-induced pulmonary fibrosis. Tauroursodeoxycholic acid (TUDCA), a bile acid with chaperone properties, is an inhibitor of ER stress. This study aimed to investigate the preventive effects of TUDCA on BLM-induced EMT and lung fibrosis.. The model of lung fibrosis was established by intratracheal injection with a single dose of BLM (3.0 mg/kg). In TUDCA + BLM group, mice were intraperitoneally injected with TUDCA (250 mg/kg) daily.. BLM-induced alveolar septal destruction and inflammatory cell infiltration were alleviated by TUDCA. BLM-induced interstitial collagen deposition, as determined by Sirius Red staining, was attenuated by TUDCA. BLM-induced elevation of pulmonary α-smooth muscle actin (α-SMA) and reduction of pulmonary E-cadherin were attenuated by TUDCA. BLM-induced pulmonary Smad2/3 phosphorylation was suppressed by TUDCA. BLM-induced elevation of Ki67 and PCNA was inhibited by TUDCA in mice lungs. In addition, BLM-induced elevation of HO-1 (heme oxygenase-1) and 3-NT (3-nitrotyrosine) was alleviated by TUDCA. Finally, BLM-induced upregulation of pulmonary GRP78 and CHOP was attenuated by TUDCA.. These results provide evidence that TUDCA pretreatment inhibits Smad2/3-medited EMT and subsequent lung fibrosis partially through suppressing BLM-induced ER stress and oxidative stress.

Topics: Animals; Bleomycin; Disease Models, Animal; Endoplasmic Reticulum Chaperone BiP; Endoplasmic Reticulum Stress; Epithelial-Mesenchymal Transition; Lung; Male; Mice; Mice, Inbred C57BL; Oxidative Stress; Phosphorylation; Pulmonary Fibrosis; Signal Transduction; Taurochenodeoxycholic Acid; Up-Regulation

In this study, we study the transplantation of tauroursodeoxycholic acid (TUDCA)-induced M2-phenotype (M2) macrophages and their ability to promote anti-neuroinflammatory effects and functional recovery in a spinal cord injury (SCI) model.. To this end, compared to the granulocyte-macrophage colony-stimulating factor (GM-CSF), we evaluated whether TUDCA effectively differentiates bone marrow-derived macrophages (BMDMs) into M2 macrophages.. The M2 expression markers in the TUDCA-treated BMDM group were increased more than those in the GM-CSF-treated BMDM group. After the SCI and transplantation steps, pro-inflammatory cytokine levels and the mitogen-activated protein kinase (MAPK) pathway were significantly decreased in the TUDCA-induced M2 group more than they were in the GM-CSF-induced M1 group and in the TUDCA group. Moreover, the TUDCA-induced M2 group showed significantly enhanced tissue volumes and improved motor functions compared to the GM-CSF-induced M1 group and the TUDCA group. In addition, biotinylated dextran amine (BDA)-labelled corticospinal tract (CST) axons and neuronal nuclei marker (NeuN) levels were increased in the TUDCA-induced M2 group more than those in the GM-CSF-induced M1 group and the TUDCA group.. This study demonstrates that the transplantation of TUDCA-induced M2 macrophages promotes an anti-neuroinflammatory effect and motor function recovery in SCI. Therefore, we suggest that the transplantation of TUDCA-induced M2 macrophages represents a possible alternative cell therapy for SCI.

Topics: Animals; Cells, Cultured; Female; Inflammation; Macrophages; Rats; Rats, Sprague-Dawley; Recovery of Function; Spinal Cord Injuries; Taurochenodeoxycholic Acid

Bile salt hydrolase (BSH)-producing bacteria are negatively related to the body weight gain and energy storage of the host. We aimed to obtain a novel BSH-producing strain with excellent anti-obesity effect and explained its mechanism. Here, we selected a strain named Lactiplantibacillus plantarum H-87 (H-87) with excellent ability to hydrolyze glycochenodeoxycholic acid (GCDCA) and tauroursodeoxycholic acid (TUDCA) in vitro from 12 lactobacilli, and evaluated its anti-obesity effect in high-fat diet (HFD)-fed C57BL/6J mice. The results suggested that H-87 could inhibit HFD-induced body weight gain, fat accumulation, liver lipogenesis and injury, insulin resistance and dyslipidemia. In addition, H-87 could colonize in the ileum and hydrolyze GCDCA and TUDCA, reflected as changes in the concentrations of GCDCA, TUDCA, CDCA and UDCA in the ileum or liver. Furthermore, the study identified that H-87 reduced TUDCA and GCDCA levels in the ileum, which decreased the GLP-1 secretion by L cells to alleviate insulin resistance in HFD-fed mice. Furthermore, H-87 increased the CDCA level in the ileum and liver to activate FXR signaling pathways to inhibit liver lipogenesis in HFD-fed mice. In addition, the decrease of intestinal conjugated bile acids (TUDCA and GCDCA) also increased fecal lipid content and decreased intestinal lipid digestibility. In conclusion, H-87 could inhibit liver fat deposition, insulin resistance and lipid digestion by changing bile acid enterohepatic circulation, and eventually alleviate HFD-induced obesity.

Topics: Animals; Bile Acids and Salts; Diet, High-Fat; Dyslipidemias; Glycochenodeoxycholic Acid; Insulin Resistance; Lactobacillus plantarum; Lipid Metabolism; Liver; Liver Diseases; Male; Mice; Mice, Inbred C57BL; Obesity; Taurochenodeoxycholic Acid

Despite advances in the pathogenesis of Tauroursodeoxycholic acid (TUDCA) on bone, the understanding of the effects and mechanisms of bone osseointegration in TUDCA-associated Hydroxyapatite (HA)-coated titanium implants remains poor. Therefore, the present work was aimed to evaluate the effect of local administration with TUDCA on HA-coated titanium implants osseointegration in ovariectomized(OVX) rats and further investigation of the possible mechanism. Twelve weeks after bilateral ovariectomy, all animals were randomly divided into three groups: sham operation(Sham) group, OVX group and TUDCA group, and all the rats from Sham group and OVX group received HA implants and animals belonging to group TUDCA received TUDCA-HA implants until death at 12 weeks. The bilateral femurs of rats were harvested for evaluation. TUDCA increased new bone formation around the surface of titanium rods and push-out force other than group OVX. Histology, Micro-CT and biochemical analysis results showed systemic TUDCA showed positive effects than OVX group on bone formation in osteopenic rats, with beneficial effect on via activation OPG/RANKL pathway and BMP-2/Smad1 pathway and microarchitecture as well as by reducing protein expression of TNF-α and IFN-γ. The present study suggests that local use of TUDCA may bring benefits to the osseointegration of HA-coated titanium implants in patients with osteoporosis, and this effect may be related to the inhibition of inflammatory reaction and promotion of osteogenesis.

Topics: Animals; Coated Materials, Biocompatible; Durapatite; Female; Osseointegration; Ovariectomy; Prostheses and Implants; Rats; Rats, Sprague-Dawley; Taurochenodeoxycholic Acid; Titanium

Glucocorticoids are known to induce skeletal muscle atrophy by suppressing protein synthesis and promoting protein degradation. Tauroursodeoxycholic acid (TUDCA) has beneficial effects in several diseases, such as hepatobiliary disorders, hindlimb ischemia and glucocorticoid-induced osteoporosis. However, the effects of TUDCA on glucocorticoid -induced skeletal muscle atrophy remains unknown. Therefore, in the present research, we explored the effects of TUDCA on dexamethasone (DEX)-induced loss and the potential mechanisms involved. We found TUDCA alleviated DEX-induced muscle wasting in C2C12 myotubes, identified by improved myotube differentiation index and expression of myogenin and MHC. And it showed that TUDCA activated the Akt/mTOR/S6K signaling pathway and inhibited FoxO3a transcriptional activity to decreased expression of MuRF1 and Atrogin-1, while blocking Akt by MK2206 blocked these effects of TUDCA on myotubes. Besides, TUDCA also attenuated DEX-induced apoptosis of myotubes. Furthermore, TUDCA was administrated to the mouse model of DEX-induced skeletal muscle atrophy. The results showed that TUDCA improved DEX-induced skeletal muscle atrophy and weakness (identified by increased grip strength and prolonged running exhaustive time) in mice by suppression of apoptosis, reduction of protein degradation and promotion of protein synthesis. Taken together, our research proved for the first time that TUDCA protected against DEX-induced skeletal muscle atrophy not only by improving myogenic differentiation and protein synthesis, but also through decreasing protein degradation and apoptosis of skeletal muscle.

Topics: Animals; Apoptosis; Cell Line; Dexamethasone; Enzyme Activation; Male; Mice, Inbred C57BL; Muscle Fibers, Skeletal; Muscle, Skeletal; Muscular Atrophy; Proto-Oncogene Proteins c-akt; Taurochenodeoxycholic Acid

Endoplasmic reticulum (ER) stress, a dysfunction in protein folding capacity of the ER, is involved in many physiological responses including mammalian reproductive systems. Studies have shown that ER stress interferes with the developmental process of in vitro oocyte maturation and embryo development; however, little is known about its effects on bovine preimplantation embryonic development. In this study, we examined the effects of ER stress during IVC on developmental competency and cryo-tolerance in bovine embryos. IVF-derived zygotes were cultured in CR1aa medium supplemented with tauroursodeoxycholic acid (TUDCA) and/or tunicamycin (TM), which are ER stress-inhibitory and stress-inducing agents, respectively, for 8 days. TM treatment decreased the blastocyst developmental rate and increased the percentage of apoptotic cells compared to that in the control group (10.2 ± 2.3% vs. 39.75 ± 1.3% and 17.8 ± 1.2% vs. 3.6 ± 1.1%, respectively; P < 0.01). However, the blastocyst developmental rate was increased and the percentage of apoptotic cells was decreased by addition of TUDCA in IVC medium compared to that in the control group (50.9 ± 0.9% vs. 39.75 ± 1.3% and 1.13 ± 1.0% vs. 3.6 ± 1.1%, respectively; P < 0.01). Importantly, in the group treated with TM plus TUDCA, the developmental rate and the percentage of apoptotic cells in blastocysts were similar to that in the control group, indicating that TUDCA ameliorates the adverse effects of TM alone on embryo development. In addition, TUDCA treatment significantly reduced the reactive oxygen species, expression of ER stress (GRP78, ATF4, ATF6, IER1, and sXBP1) and pro-apoptotic (CHOP and BAX) genes, while it increased anti-apoptotic BCL2 gene expression and glutathione levels. Moreover, TUDCA improved blastocyst cryo-tolerance as marked by a significantly increased hatching rate and decreased the number of apoptotic cells recorded at 48 h after a post-warming. Therefore, in concordance with a previous report in mice or pig, we showed that TUDCA supplementation during IVC increases the developmental competency of bovine in vitro-derived embryos. Additionally, we found that the presence of TUDCA in IVC medium improves the cryo-tolerance of bovine embryos. These results suggest that modulation of ER stress during IVC contributes to the production of high-quality bovine embryos in terms of cryo-tolerance.

Topics: Animals; Anti-Bacterial Agents; Cattle; Cholagogues and Choleretics; Cryopreservation; Dose-Response Relationship, Drug; Embryo Culture Techniques; Embryonic Development; Endoplasmic Reticulum Chaperone BiP; Endoplasmic Reticulum Stress; Taurochenodeoxycholic Acid; Tunicamycin

Angiogenesis is a crucial process during bone tissue regeneration. The aim of this study was to investigate the angiogenic activity and the potentiation of bone regeneration via angiogenesis using tauroursodeoxycholic acid (TUDCA) in vitro and in vivo. We investigated the effect of TUDCA on proliferation and angiogenic differentiation in human umbilical vein endothelial cells (HUVECs) and the associated signaling pathway. Proliferation was determined using crystal violet assay. Angiogenic effects were evaluated based on cell migration and tube formation. In order to explore TUDCA-signaling pathways, phosphorylation of mitogen activated protein kinase, protein kinase B (AKT), and endothelial nitric oxide synthase (eNOS) was determined using western blot. Furthermore, in vivo bone formation and angiogenesis were determined using a New Zealand outbred albino rabbit calvarial defect model, while angiogenesis and bone formation were evaluated using micro-CT and histological analysis. Our results show that TUDCA significantly increased cell proliferation. Moreover, TUDCA enhanced cell migration and tube formation in HUVECs. TUDCA increased the phosphorylation of AKT, ERK1/2, c-Jun N-terminal kinase, and eNOS. Specific inhibitors of ERK1/2 (PD98059), JNK (SP600125), and AKT (AKT1/2) inhibited the TUDCA-induced migration and tube formation, while the p38 inhibitor (SB203580) did not. The in vivo study used TUDCA to accelerate new blood vessel formation and promoted bone formation in rabbit calvarial defect model. These results indicate that TUDCA plays a critical role in enhancing the angiogenesis of endothelial cells and in vivo new bone regeneration. The use of TUDCA may contribute to the regeneration of bone tissue by improving angiogenesis.

Topics: Animals; Bone Regeneration; Cell Proliferation; Human Umbilical Vein Endothelial Cells; Neovascularization, Physiologic; Osteogenesis; Proto-Oncogene Proteins c-akt; Rabbits; Taurochenodeoxycholic Acid

Epithelial‑to‑mesenchymal transition (EMT) of human lens epithelial cells (HLECs) serve an important role in cataract formation. The endoplasmic reticulum stress response (ER stress) has been demonstrated to regulate EMT in a number of tissues. The aim of the present study was to demonstrate the role of ER stress on EMT in HLECs. HLECs were treated with tunicamycin (TM) or thapsigargin (TG) to disturb ER homeostasis, and 4‑phenylbutyric acid (PBA) or sodium tauroursodeoxycholate (TUDCA) to restore ER homeostasis. Cell morphology was evaluated after 24 h. The long axis and aspect ratio of the cells were analyzed using ImageJ software. The results demonstrated that HLECs adopted an elongated morphology following treatment with TG, and the cellular aspect ratio increased. However, this morphological change was not observed following combination treatment with TG and PBA. Western blot analysis and immunofluorescence staining were used to measure the protein expression levels. A wound‑healing assay was performed to evaluate cell migration. Treatment with TM or TG increased the expression of the ER stress markers glucose‑regulated protein 78, phosphorylated eukaryotic initiation factor 2α, activating transcription factor (ATF)6, ATF4 and inositol‑requiring protein 1α and the EMT markers fibronectin, vimentin, α‑smooth muscle actin and neural cadherin. Furthermore, treatment with TM or TG decreased the expression of the epithelial cell marker epithelial cadherin and enhanced cell migration, which effects were inhibited following treatment with PBA or TUDCA. These results indicates that enhanced ER stress induced EMT and subsequently increased cell migration in HLECs in vitro.

Topics: Cataract; Cell Line; Endoplasmic Reticulum Stress; Epithelial Cells; Epithelial-Mesenchymal Transition; Eye Proteins; Humans; Lens, Crystalline; Phenylbutyrates; Taurochenodeoxycholic Acid; Thapsigargin; Tunicamycin

Early brain injury (EBI) has been recognized as a major cause of poor clinical outcomes in patients with spontaneous subarachnoid hemorrhage (SAH). Endoplasmic reticulum (ER) stress contributes to EBI, but its impact on cerebrovascular function following SAH remains poorly defined. We tested the hypothesis that blocking ER stress by the inhibitor Tauroursodeoxycholic acid (TUDCA) attenuates EBI, which is associated with the rescue of cerebrovascular function defined by local cerebral blood flow and vascular permeability and ER-stress mediated-apoptosis in mouse models. We first preconditioned mice with TUDCA (500 mg/kg/d × 3 days) before SAH and evaluated them for cerebrovascular function by analyzing cerebral cortical perfusion and blood-brain-barrier (BBB) permeability, unfolded protein response (UPR), ER stress-mediated apoptosis and neurological function after SAH. We found that SAH induced a rapidly reduction in cerebral blood flow and an elevated level of ER stress, which lasted for 24 h. The level of neurological deficits was closely associated with the reduction of cerebral blood flow and excessive ER stress. TUDCA improved cerebral blood flow, reduced BBB permeability, inhibited the ER stress through the PERK/eIF2α/ATF4/CHOP signaling pathway, blocked the Caspase-12-dependent ER-stress mediated apoptosis, resulting in significantly improved neurological function of mice subjected to SAH. These data suggest that blocking ER stress prevents EBI and improves the outcome of mice subjected to experimental SAH. These beneficial effects are associated with the restoration of SAH-associated cerebrovascular dysfunction and reduction of the ER-stress induced apoptosis, but additional signaling pathways of ER stress may also be involved.

Topics: Animals; Apoptosis; Brain; Endoplasmic Reticulum Stress; Male; Mice, Inbred C57BL; Neuroprotective Agents; Signal Transduction; Subarachnoid Hemorrhage; Taurochenodeoxycholic Acid

DNA damage associated with assisted reproductive technologies is an important factor affecting gamete fertility and embryo development. Activation of the TGR5 receptor by tauroursodeoxycholic acid (TUDCA) has been shown to reduce endoplasmic reticulum (ER) stress in embryos; however, its effect on genome damage responses (GDR) activation to facilitate DNA damage repair has not been examined. This study aimed to investigate the effect of TUDCA on DNA damage repair and embryo development. In a porcine model of ultraviolet light (UV)-induced nuclear stress, TUDCA reduced DNA damage and ER stress in developing embryos, as measured by γH2AX and glucose-regulated protein 78 immunofluorescence, respectively. TUDCA was equally able to rescue early embryo development. No difference in total cell number, DNA damage, or percentage of apoptotic cells, measured by cleaved caspase 3 immunofluorescence, was noted in embryos that reached the blastocyst stage. Interestingly, Dicer-substrate short interfering RNA-mediated disruption of TGR5 signaling abrogated the beneficial effects of TUDCA on UV-treated embryos. Quantitative PCR analysis revealed activation of the GDR, through increased messenger RNA abundance of DNAPK, 53BP1, and DNA ligase IV, as well as the ER stress response, through increased spliced XBP1 and X-linked inhibitor of apoptosis. Results from this study demonstrated that TUDCA activates TGR5-mediated signaling to reduce DNA damage and improve embryo development after UV exposure.

Topics: Animals; Apoptosis; Blastocyst; Cells, Cultured; DNA Damage; DNA Repair; Embryonic Development; Endoplasmic Reticulum Stress; Female; Fertilization in Vitro; Gene Knockdown Techniques; In Vitro Oocyte Maturation Techniques; Oocyte Retrieval; Ovary; Receptors, G-Protein-Coupled; Signal Transduction; Swine; Taurochenodeoxycholic Acid; Ultraviolet Rays; Unfolded Protein Response; Zygote

The objective of this study was to examine the effect of tauroursodeoxycholic acid (TUDCA) on intracytoplasmic sperm injection (ICSI) embryos by evaluating endoplasmic reticulum (ER) stress, apoptosis, and embryo developmental competence in vitro and in vivo.. ER stress-associated genes and apoptosis-associated genes were measured and apoptosis index was analyzed. Embryo developmental competence was assessed in vitro and in vivo via the inner cell mass (ICM)/trophectoderm (TE) index, pregnancy and implantation rates, and birth rate.. The relative mRNA and protein expression of binding immunoglobulin protein (BIP) was significantly higher in the ICSI embryo group without TUDCA treatment (ICSI-C) than in the in vitro fertilization (IVF) group and in the ICSI embryo group with TUDCA treatment (200 μM) (ICSI-T), while TUDCA ameliorated ER stress in ICSI embryos. Embryos in the ICSI-C group showed a higher apoptosis index than those in the IVF group and ICSI-T group, and there was no significant difference between the IVF group and ICSI-T group. TUDCA can significantly improve ICSI embryo developmental competence in vitro and in vivo based on the ICM/TE index, pregnancy and implantation rates, and birth rate.. ICSI embryos manifested high ER stress and high apoptosis, while TUDCA ameliorated ER stress and reduced apoptosis in ICSI embryos. TUDCA can significantly improve the developmental competence of ICSI embryos in vitro and in vivo. This study provides a new idea for improving the efficiency of ICSI, and it will also have a positive effect on the development of assisted reproduction technologies for humans and other animals.

Topics: Animals; Apoptosis; Birth Rate; Cholagogues and Choleretics; Embryo Implantation; Embryo, Mammalian; Embryonic Development; Endoplasmic Reticulum Stress; Female; Fertilization in Vitro; Male; Mice, Inbred C57BL; Oocytes; Pregnancy; Pregnancy Rate; Reproductive Techniques, Assisted; Sperm Injections, Intracytoplasmic; Taurochenodeoxycholic Acid

B cells orchestrate pro-survival and pro-apoptotic inputs during unfolded protein response (UPR) to translate, fold, sort, secrete and recycle immunoglobulins. In common variable immunodeficiency (CVID) patients, activated B cells are predisposed to an overload of abnormally processed, misfolded immunoglobulins. Using highly accurate transcript measurements, we show that expression of UPR genes and immunoglobulin chains differs qualitatively and quantitatively during the first 4 h of chemically induced UPR in B cells from CVID patients and a healthy subject. We tested thapsigargin or tunicamycin as stressors and 4-phenylbutyrate, dimethyl sulfoxide and tauroursodeoxycholic acid as chemical chaperones. We found an early and robust decrease of the UPR upon endoplasmic reticulum (ER) stress in CVID patient cells compared to the healthy control consistent with the disease phenotype. The chemical chaperones increased the UPR in the CVID patient cells in response to the stressors, suggesting that misfolded immunoglobulins were stabilized. We suggest that the AMP-dependent transcription factor alpha branch of the UPR is disturbed in CVID patients, underlying the observed expression behavior.

Topics: B-Lymphocytes; Cells, Cultured; Common Variable Immunodeficiency; Dimethyl Sulfoxide; Endoplasmic Reticulum Stress; Gene Expression Profiling; Gene Expression Regulation; Gene Regulatory Networks; Humans; Immunoglobulins; Phenylbutyrates; Taurochenodeoxycholic Acid; Thapsigargin; Transcription Factors; Tunicamycin; Unfolded Protein Response

Silybin shows good effects against obesity and metabolic syndrome, but the systemic modulation effect of silybin has not been fully revealed. This study aims to investigate the metabolic regulation by silybin of nonalcoholic fatty liver disease (NAFLD). C57BL/6 J mice were fed a high-fat/high-cholesterol diet for 8 weeks and treated with silybin (50 or 100 mg/kg/day) and sodium tauroursodeoxycholate (TUDCA, 50 mg/kg/day) by gavage for the last 4 weeks. Blood biochemical indexes and hepatic lipid measurement as well as Oil red O staining of the liver were conducted to evaluate the model and the lipid-lowering effect of silybin and TUDCA. Furthermore, serum and liver samples were detected by a metabolomic platform based on gas chromatography-mass spectrometry (GC/MS). Multivariate/univariate data analysis and pathway analysis were used to investigate differential metabolites and metabolic pathways. The results showed that the mouse NAFLD model was established successfully and that silybin and TUDCA significantly lowered both serum and hepatic lipid accumulation. Metabolomic analysis of serum and liver showed that a high-fat/high-cholesterol diet caused abnormal metabolism of metabolites involved in lipid metabolism, polyol metabolism, amino acid metabolism, the urea cycle and the TCA cycle. Silybin and TUDCA treatment both reversed metabolic disorders caused by HFD feeding. In conclusion, a high-fat/high-cholesterol diet caused metabolic abnormalities in the serum and liver of mice, and silybin treatment improved hepatic lipid accumulation and modulated global metabolic pathways, which provided a possible explanation of its multiple target mechanism.

Topics: Animals; Cholesterol, Dietary; Diet, High-Fat; Disease Models, Animal; Dose-Response Relationship, Drug; Lipid Metabolism; Liver; Male; Metabolomics; Mice; Mice, Inbred C57BL; Non-alcoholic Fatty Liver Disease; Silybin; Taurochenodeoxycholic Acid

Endometriosis exerts detrimental effects on ovarian physiology and compromises follicular health. Granulosa cells from patients with endometriosis are characterized by increased apoptosis, as well as high oxidative stress. Endoplasmic reticulum (ER) stress, a local factor closely associated with oxidative stress, has emerged as a critical regulator of ovarian function. We hypothesized that ER stress is activated by high oxidative stress in granulosa cells in ovaries with endometrioma and that this mediates oxidative stress-induced apoptosis. Human granulosa-lutein cells (GLCs) from patients with endometrioma expressed high levels of mRNAs associated with the unfolded protein response (UPR). In addition, the levels of phosphorylated ER stress sensor proteins, inositol-requiring enzyme 1 (IRE1) and double-stranded RNA-activated protein kinase-like ER kinase (PERK), were elevated in granulosa cells from patients with endometrioma. Given that ER stress results in phosphorylation of ER stress sensor proteins and induces UPR factors, these findings indicate that these cells were under ER stress. H2O2, an inducer of oxidative stress, increased expression of UPR-associated mRNAs in cultured human GLCs, and this effect was abrogated by pretreatment with tauroursodeoxycholic acid (TUDCA), an ER stress inhibitor in clinical use. Treatment with H2O2 increased apoptosis and the activity of the pro-apoptotic factors caspase-8 and caspase-3, both of which were attenuated by TUDCA. Our findings suggest that activated ER stress induced by high oxidative stress in granulosa cells in ovaries with endometrioma mediates apoptosis of these cells, leading to ovarian dysfunction in patients with endometriosis.

Topics: Adult; Apoptosis; Caspase 3; Caspase 8; Cell Movement; Cell Proliferation; eIF-2 Kinase; Endometriosis; Endoplasmic Reticulum; Endoplasmic Reticulum Stress; Endoribonucleases; Female; Gene Expression Regulation; Granulosa Cells; Humans; Hydrogen Peroxide; Ovary; Oxidative Stress; Primary Cell Culture; Protein Serine-Threonine Kinases; Signal Transduction; Taurochenodeoxycholic Acid; Unfolded Protein Response

We aimed to determine sphingolipid levels and examine apoptotic pathways in human retinal pigment epithelial cells (ARPE-19) undergoing endoplasmic reticulum (ER) stress.. Cells were treated with tunicamycin (TM) to induce ER stress and tauroursodeoxycholic acid (TUDCA), an ER stress inhibitor, was administered to decrease cytotoxicity. Cell viability was measured by MTT assay. Levels of C16-C24 sphingomyelins (SM) and C16-C24 ceramides (CERs) were determined by LC-MS/MS. Glucose-regulated protein 78-kd (GRP78) and nuclear factor kappa-b subunit 1 (NFκB1) gene expressions were evaluated by quantitative PCR analysis, while GRP 78, NF-κB p65, cleaved caspase-3 and caspase-12 protein levels were assesed by immunofluorescence. Ceramide-1-phosphate (C1P) levels were determined by immunoassay, while caspase -3 and -12 activity in cell lysates were measured via a fluorometric method.. Induction of ER stress in TM treated groups were confirmed by significantly increased mRNA and protein levels of GRP78. TM significantly decreased cell viability compared to controls. Treatment with TUDCA along with TM significantly increased cell viability compared to the TM group. A significant increase was observed in C22-C24 CERs, C1P, caspase-3, caspase-12, NFκB1 mRNA and NF-κB p65 protein levels in cells treated with TM compared to controls. Administration of TUDCA lead to a partial decrease in GRP78 expression, NFκB1 mRNA, NF-κB p65 protein, C22-C24 CERs and C1P levels along with a decrease in caspase-3 and -12 activity.. The results of this study reveal the presence of increased long chain CERs, C1P and apoptotic markers in retinal cells undergoing ER stress.

Topics: Apoptosis; Cell Line; Ceramides; Chromatography, Liquid; Endoplasmic Reticulum Chaperone BiP; Endoplasmic Reticulum Stress; Gene Expression Regulation; Heat-Shock Proteins; Humans; NF-kappa B p50 Subunit; Retinal Pigment Epithelium; Signal Transduction; Sphingolipids; Sphingomyelins; Tandem Mass Spectrometry; Taurochenodeoxycholic Acid; Tunicamycin

We have previously reported that regulation of endoplasmic reticulum (ER) stress during in vitro culture acutely increases bovine embryo developmental rate and cryotolerance; these data indicate that ER stress is a critical factor reducing the quality of in vitro-produced embryos. In the current follow-up study, we examined whether ER stress attenuation during in vitro maturation influences meiotic maturation, oocyte quality, and subsequent embryonic development. Bovine cumulus oocyte complexes (COCs) derived from slaughterhouse ovaries were matured with or without tauroursodeoxycholic acid (TUDCA), a selective inhibitor of ER stress (0, 50, 100, and 200 µM) for 22 h followed by in vitro fertilization, and zygotes were cultured for 8 days. Of the different doses of TUDCA, 100 μM TUDCA significantly increased the maturation rate, and decreased reactive oxygen species in denuded oocytes, and appeared lower number of apoptotic cells in matured COCs. Subsequently, treatment of TUDCA (100 µM) decreased the localization and amount of GRP78/BIP protein level as well as ER stress (GRP78/BIP, PERK, IER1, ATF4, and XBP1) and apoptosis (CHOP and BAX)-related gene expression, while it increased the anti-apoptotic gene BCL2 level in matured COCs. Moreover, addition of TUDCA (100 µM) during IVM significantly improved the blastocyst formation rate (43.6 ± 1.8% vs 49.7 ± 1.3%) and decreased the number of apoptotic cells (7.7 ± 1.1% vs 5.03 ± 0.6%) in blastocysts. These findings suggest that the presence of ER stress during maturation impairs the developmental competence of bovine COCs and that this process can be reversed by TUDCA.

Topics: Animals; Apoptosis; Cattle; Drug Evaluation, Preclinical; Embryonic Development; Endoplasmic Reticulum Stress; In Vitro Oocyte Maturation Techniques; Oocytes; Reactive Oxygen Species; Taurochenodeoxycholic Acid

Polycystic ovary syndrome (PCOS) is associated with hyperandrogenism, and we previously found that androgens activate endoplasmic reticulum (ER) stress in granulosa cells from patients with PCOS. In addition, recent studies demonstrated the accumulation of advanced glycation end products (AGEs) in granulosa cells from PCOS patients, which contribute to the pathology. Therefore, we hypothesized that androgens upregulate the receptor for AGEs (RAGE) expression in granulosa cells by activating ER stress, thereby increasing the accumulation of AGEs in these cells and contributing to the pathology. In the present study, we show that testosterone increases RAGE expression and AGE accumulation in cultured human granulosa-lutein cells (GLCs), and this is reduced by pretreatment with tauroursodeoxycholic acid (TUDCA), an ER stress inhibitor in clinical use. Knockdown of the transcription factor C/EBP homologous protein (CHOP), an unfolded protein response factor activated by ER stress, inhibits testosterone-induced RAGE expression and AGE accumulation. The expression of RAGE and the accumulation of AGEs are upregulated in granulosa cells from PCOS patients and dehydroepiandrosterone-induced PCOS mice. Administration of the RAGE inhibitor FPS-ZM1 or TUDCA to PCOS mice reduces RAGE expression and AGE accumulation in granulosa cells, improves their estrous cycle, and reduces the number of atretic antral follicles. In summary, our findings indicate that hyperandrogenism in PCOS increases the expression of RAGE and accumulation of AGEs in the ovary by activating ER stress, and that targeting the AGE-RAGE system, either by using a RAGE inhibitor or a clinically available ER stress inhibitor, may represent a novel approach to PCOS therapy.

Topics: Animals; Benzamides; Case-Control Studies; Cells, Cultured; Drug Evaluation, Preclinical; Endoplasmic Reticulum Stress; Female; Glycation End Products, Advanced; Granulosa Cells; Humans; Hyperandrogenism; Mice, Inbred BALB C; Polycystic Ovary Syndrome; Receptor for Advanced Glycation End Products; Taurochenodeoxycholic Acid; Testosterone

Tauroursodeoxycholic acid (TUDCA) has been reported to be protective against apoptosis and oxidative stress in various cell types. A few studies have demonstrated otoprotective effects of TUDCA in mouse models. This study investigated the otoprotective effects of TUDCA in cisplatin (CXP)-induced hearing-loss rats. Eight-week-old female Sprague-Dawley rats were used. The CXP group received intraperitoneal injection of CXP at a dose of 5 mg/kg from day 1 to day 3. The CXP + TUDCA group received an intraperitoneal injection of 5 mg/kg CXP and 100 mg/kg TUDCA from day 1 to day 3. The mRNA expression levels of heme oxygenase 1 (HO1) and superoxide dismutase 2 (SOD2) were measured, and the protein levels of caspase 3, cleaved caspase 3, and aryl hydrocarbon receptor (AhR) were evaluated. The CXP group demonstrated higher mean auditory brainstem responses (ABR) thresholds than the control group. The mean ABR threshold shifts were lower in the CXP + TUDCA group than in the CXP group. The CXP group showed elevated HO1 and SOD2 mRNA expression levels compared to the control group, but these changes were reversed in the CXP + TUDCA group. Compared to the levels in the control group, caspase 3, cleaved caspase 3, and AhR levels were higher in the CXP group, but the increase in cleaved caspase-3 was attenuated in the CXP + TUDCA group. The cochlea showed a higher number of spiral ganglion cells and outer hair cells in the CXP + TUDCA group than in the CXP group. TUDCA reduced CXP-induced hearing loss in adult rats. The HO1-mediated antioxidative effects attenuated apoptosis in the cochlea, but AhR activation was not reversed.

Topics: Animals; Antineoplastic Agents; Auditory Threshold; Cisplatin; Cochlea; Evoked Potentials, Auditory, Brain Stem; Female; Hearing Loss; Rats; Rats, Sprague-Dawley; Taurochenodeoxycholic Acid

Cognitive decline is one of the complications of type 2 diabetes (T2D). Intermittent fasting (IF) is a promising dietary intervention for alleviating T2D symptoms, but its protective effect on diabetes-driven cognitive dysfunction remains elusive. Here, we find that a 28-day IF regimen for diabetic mice improves behavioral impairment via a microbiota-metabolites-brain axis: IF enhances mitochondrial biogenesis and energy metabolism gene expression in hippocampus, re-structures the gut microbiota, and improves microbial metabolites that are related to cognitive function. Moreover, strong connections are observed between IF affected genes, microbiota and metabolites, as assessed by integrative modelling. Removing gut microbiota with antibiotics partly abolishes the neuroprotective effects of IF. Administration of 3-indolepropionic acid, serotonin, short chain fatty acids or tauroursodeoxycholic acid shows a similar effect to IF in terms of improving cognitive function. Together, our study purports the microbiota-metabolites-brain axis as a mechanism that can enable therapeutic strategies against metabolism-implicated cognitive pathophysiologies.

Topics: Animals; Brain; Cognition; Cognitive Dysfunction; Computational Biology; Diabetes Mellitus, Experimental; Diabetes Mellitus, Type 2; Energy Metabolism; Fasting; Fatty Acids, Volatile; Gastrointestinal Microbiome; Gene Expression Regulation; Hippocampus; Indoles; Insulin Resistance; Male; Metabolome; Mice; Propionates; RNA, Ribosomal, 16S; Serotonin; Synapses; Taurochenodeoxycholic Acid

Polymorphism at the 17q21 gene locus and wheezing responses to rhinovirus (RV) early in childhood conspire to increase the risk of developing asthma. However, the mechanisms mediating this gene-environment interaction remain unclear. In this study, we investigated the impact of one of the 17q21-encoded genes,

Topics: A549 Cells; Asthma; Bronchi; Cells, Cultured; Chromosomes, Human, Pair 17; Endoplasmic Reticulum Stress; Epithelial Cells; Fatty Acids, Monounsaturated; Genetic Predisposition to Disease; Genotype; HeLa Cells; Humans; Interferon-beta; Membrane Proteins; Nasal Mucosa; Picornaviridae Infections; Recombinant Proteins; Rhinovirus; RNA Interference; RNA, Small Interfering; Serine C-Palmitoyltransferase; Sphingolipids; Taurochenodeoxycholic Acid; Virus Replication

The steady increase in the prevalence of obesity and associated type II diabetes mellitus is a major health concern, particularly among children. Maternal obesity represents a risk factor that contributes to metabolic perturbations in the offspring. Endoplasmic reticulum (ER) stress has emerged as a critical mechanism involved in leptin resistance and type 2 diabetes in adult individuals. Here, we used a mouse model of maternal obesity to investigate the importance of early life ER stress in the nutritional programming of this metabolic disease. Offspring of obese dams developed glucose intolerance and displayed increased body weight, adiposity, and food intake. Moreover, maternal obesity disrupted the development of melanocortin circuits associated with neonatal hyperleptinemia and leptin resistance. ER stress-related genes were up-regulated in the hypothalamus of neonates born to obese mothers. Neonatal treatment with the ER stress-relieving drug tauroursodeoxycholic acid improved metabolic and neurodevelopmental deficits and reversed leptin resistance in the offspring of obese dams.

Topics: alpha-MSH; Animals; Animals, Newborn; Axons; Body Composition; Body Weight; Diet; Endoplasmic Reticulum Stress; Female; Hypothalamus; Male; Mice, Inbred C57BL; Obesity, Maternal; Pancreas; Pregnancy; Prenatal Exposure Delayed Effects; Pro-Opiomelanocortin; Taurochenodeoxycholic Acid

Multiple sclerosis (MS) is an inflammatory demyelinating disorder of the CNS. Bile acids are cholesterol metabolites that can signal through receptors on cells throughout the body, including in the CNS and the immune system. Whether bile acid metabolism is abnormal in MS is unknown. Using global and targeted metabolomic profiling, we identified lower levels of circulating bile acid metabolites in multiple cohorts of adult and pediatric patients with MS compared with controls. In white matter lesions from MS brain tissue, we noted the presence of bile acid receptors on immune and glial cells. To mechanistically examine the implications of lower levels of bile acids in MS, we studied the in vitro effects of an endogenous bile acid, tauroursodeoxycholic acid (TUDCA), on astrocyte and microglial polarization. TUDCA prevented neurotoxic (A1) polarization of astrocytes and proinflammatory polarization of microglia in a dose-dependent manner. TUDCA supplementation in experimental autoimmune encephalomyelitis reduced the severity of disease through its effects on G protein-coupled bile acid receptor 1 (GPBAR1). We demonstrate that bile acid metabolism was altered in MS and that bile acid supplementation prevented polarization of astrocytes and microglia to neurotoxic phenotypes and ameliorated neuropathology in an animal model of MS. These findings identify dysregulated bile acid metabolism as a potential therapeutic target in MS.

Topics: Animals; Astrocytes; Disease Models, Animal; Humans; Inflammation; Mice; Microglia; Multiple Sclerosis; Receptors, G-Protein-Coupled; Taurochenodeoxycholic Acid

Discrete calcium signals within the vascular endothelium decrease with age and contribute to impaired endothelial-dependent vasodilation. Calreticulin (Calr), a multifunctional calcium binding protein and endoplasmic reticulum (ER) chaperone, can mediate calcium signals and vascular function within the endothelial cells (ECs) of small resistance arteries. We found Calr protein expression significantly decreases with age in mesenteric arteries and examined the functional role of EC Calr in vasodilation and calcium mobilization in the context of aging. Third-order mesenteric arteries from mice with or without EC Calr knockdown were examined for calcium signals and constriction to phenylephrine (PE) or vasodilation to carbachol (CCh) after 75 wk of age. PE constriction in aged mice with or without EC Calr was unchanged. However, calcium signals and vasodilation to endothelial-dependent agonist carbachol were significantly impaired in aged EC Calr knockdown mice. Ex vivo incubation of arteries with the ER stress inhibitor tauroursodeoxycholic acid (TUDCA) significantly improved vasodilation in mice lacking EC Calr. Our data suggests diminished vascular Calr expression with age can contribute to the detrimental effects of aging on endothelial calcium regulation and vasodilation.

Topics: Aging; Animals; Calcium Signaling; Calreticulin; Carbachol; Endothelium, Vascular; Gene Deletion; Male; Mesenteric Arteries; Mice; Mice, Inbred C57BL; Phenylephrine; Taurochenodeoxycholic Acid; Vasoconstrictor Agents; Vasodilation

Functional selectivity is the ligand-specific activation of certain signal transduction pathways at a receptor and has been described for G protein-coupled receptors. However, it has not yet been described for ligands interacting with integrins without αI domain. Here, we show by molecular dynamics simulations that four side chain-modified derivatives of tauroursodeoxycholic acid (TUDC), an agonist of α

Topics: Animals; ATP Binding Cassette Transporter, Subfamily B, Member 11; Binding Sites; Cholagogues and Choleretics; ErbB Receptors; Integrin alpha5beta1; Liver; Male; MAP Kinase Signaling System; Molecular Docking Simulation; p38 Mitogen-Activated Protein Kinases; Protein Binding; Rats; Rats, Wistar; Taurochenodeoxycholic Acid; Ursodeoxycholic Acid

Obstructive sleep apnea (OSA) is associated with pulmonary fibrosis and endothelial apoptosis in pulmonary tissues. Chronic intermittent hypoxia (IH) is considered to be the primary player in OSA, but the mechanisms underlying its effect on pulmonary tissues are unknown. Endoplasmic reticulum (ER) stress induced by IH treatment plays an important role in accelerating the process of fibrosis and induction of apoptosis.. After 4 weeks of IH treatment, the expressions of two ER stress markers, glucose regulated protein-78 (Grp78) and transcription factor C/EBP homologous protein (CHOP) were increased which was prevented by administration of the ER stress attenuator, TUDCA. The expressions of PERK, but not those of ATF-6 and IRE-1, were increased. The effects of IH were accompanied by an increased number of apoptotic cells and increased expressions of cleaved caspase-3 and caspase-12 in pulmonary tissues. In addition, histological examination suggested the presence of fibrosis after chronic IH treatment, indicated by increased expression of collagen, which was associated with the up-regulation of TGF-β1 and TSP-1 that are known to promote fibrosis. Similarly, TUDCA could reduce the extent of fibrotic area and the expression levels of these proteins.. It reveals the roles of ER stress, especially the PERK pathway, in IH induced apoptosis and fibrosis in pulmonary tissues that might underlie the pulmonary complications observed in OSA.

Topics: Animals; Apoptosis; Caspase 12; Caspase 3; Endoplasmic Reticulum Chaperone BiP; Endoplasmic Reticulum Stress; Fibrosis; Hypoxia; Lung; Male; Mice; Mice, Inbred C57BL; Signal Transduction; Taurochenodeoxycholic Acid; Transcription Factor CHOP

Microgravity exposure results in vascular remodeling and cardiovascular dysfunction. Here, the effects of mitochondrial oxidative stress on vascular smooth muscle cells (VSMCs) in rat cerebral arteries under microgravity simulated by hindlimb unweighting (HU) was studied. Endoplasmic reticulum (ER)-resident transmembrane sensor proteins and phenotypic markers of rat cerebral VSMCs were examined. In HU rats, CHOP expression was increased gradually, and the upregulation of the PERK-eIF2α-ATF4 pathway was the most pronounced in cerebral arteries. Furthermore, PERK/p-PERK signaling, CHOP, GRP78 and reactive oxygen species were augmented by PERK overexpression but attenuated by the mitochondria-targeting antioxidant MitoTEMPO. Meanwhile, p-PI3K, p-Akt and p-mTOR protein levels in VSMCs were increased in HU rat cerebral arteries. Compared with the control, HU rats exhibited lower α-SMA, calponin, SM-MHC and caldesmon protein levels but higher OPN and elastin levels in cerebral VSMCs. The cerebral VSMC phenotype transition from a contractile to synthetic phenotype in HU rats was augmented by PERK overexpression and 740Y-P but reversed by MitoTEMPO and the ER stress inhibitors tauroursodeoxycholic acid (TUDCA) and 4-phenylbutyric acid (4-PBA). In summary, mitochondrial oxidative stress and ER stress induced by simulated microgravity contribute to phenotype transition of cerebral VSMCs through the PERK-eIF2a-ATF4-CHOP pathway in a rat model.

Topics: Activating Transcription Factor 4; Animals; Antioxidants; Cerebral Arteries; eIF-2 Kinase; Endoplasmic Reticulum; Eukaryotic Initiation Factor-2; Gene Expression Regulation; Heat-Shock Proteins; Hindlimb Suspension; Male; Mitochondria; Muscle, Smooth, Vascular; Myocytes, Smooth Muscle; Organophosphorus Compounds; Phenylbutyrates; Phosphatidylinositol 3-Kinases; Piperidines; Proto-Oncogene Proteins c-akt; Rats; Rats, Sprague-Dawley; Signal Transduction; Taurochenodeoxycholic Acid; TOR Serine-Threonine Kinases; Transcription Factor CHOP

Metabolic (Met) syndrome is characterized by hypertension, insulin resistance and dyslipidaemia with high risk of cardiovascular disease. Endoplasmic reticulum (ER) stress is a key contributor in the pathogenesis of Met syndrome. The current study investigates the effect of Tauroursodeoxycholate (TUDCA), an ER stress inhibitor, on Met syndrome-induced cardiovascular complications and the possible underlying signalling mechanisms. Met syndrome was induced in rats, which were then treated with TUDCA. Body weight, blood pressure, glucose tolerance and insulin tolerance tests were performed. ER stress, survival and oxidative stress markers were measured in heart and aorta tissue. The results showed that TUDCA improved metabolic parameters in rats with Met syndrome. Treatment mitigated the Met syndrome-induced cardiovascular complications through upregulating survival markers and downregulating ER and oxidative stress markers. These results highlight the protective effect of ER stress inhibition as a potential target in the management of cardiovascular complications associated with Met syndrome.

Topics: Animals; Biomarkers; Blood Pressure; Body Weight; Cardiovascular Diseases; Disease Models, Animal; Disease Susceptibility; Endoplasmic Reticulum Stress; Endothelium; Immunohistochemistry; Metabolic Syndrome; Phenotype; Rats; Taurochenodeoxycholic Acid

Obesity is associated with the activation of cellular responses, such as endoplasmic reticulum (ER) stress. Here, we show that leptin-deficient ob/ob mice display elevated hypothalamic ER stress as early as postnatal day 10, i.e., prior to the development of obesity in this mouse model. Neonatal treatment of ob/ob mice with the ER stress-relieving drug tauroursodeoxycholic acid (TUDCA) causes long-term amelioration of body weight, food intake, glucose homeostasis, and pro-opiomelanocortin (POMC) projections. Cells exposed to ER stress often activate autophagy. Accordingly, we report that in vitro induction of ER stress and neonatal leptin deficiency in vivo activate hypothalamic autophagy-related genes. Furthermore, genetic deletion of autophagy in pro-opiomelanocortin neurons of ob/ob mice worsens their glucose homeostasis, adiposity, hyperphagia, and POMC neuronal projections, all of which are ameliorated with neonatal TUDCA treatment. Together, our data highlight the importance of early life ER stress-autophagy pathway in influencing hypothalamic circuits and metabolic regulation.

Topics: Adiposity; Animals; Antiviral Agents; Autophagy; Autophagy-Related Protein 7; Body Weight; Cholagogues and Choleretics; Disease Models, Animal; Eating; Endoplasmic Reticulum Stress; Energy Metabolism; Feeding Behavior; Homeostasis; Hyperphagia; Hypothalamus; Leptin; Male; Metabolic Diseases; Mice; Mice, Inbred Strains; Mice, Knockout; Neuroendocrinology; Neurogenesis; Obesity; Pro-Opiomelanocortin; Taurochenodeoxycholic Acid

The novel copper complex [Cu(phen)2(salubrinal)](ClO4)2 (C0SAL) has been synthesised and characterised. Copper(ii) is coordinated by salubrinal through the thionic group, as shown by the UV-Vis, IR, ESI-MS and tandem mass results, together with the theoretical calculations. The formed complex showed a DPPH radical scavenging ability higher than that of salubrinal alone. Studies on lipid oxidation inhibition showed that the C0SAL concentration, required to inhibit the enzyme, was lower than that of salubrinal. The inhibition of the enzyme could take place via allosteric modulation, as suggested by docking calculations. C0SAL showed a good cytotoxic activity on A2780 cells, 82 fold higher than that of the precursor salubrinal and 1.4 fold higher than that of [Cu(phen)2(H2O)](ClO4)2. Treatment with C0SAL in SKOV3 ovarian cancer cells induced expression of GRP-78 and DDIT3 regulators of ER-stress response. The cytotoxic effect of C0SAL was reverted in the presence of TUDCA, suggesting that C0SAL induces cell death through ER-stress. In A2780 cells treated with C0SAL γ-H2AX was accumulated, suggesting that DNA damage was also involved.

Topics: Antiviral Agents; Cell Line, Tumor; Cell Survival; Cinnamates; Copper; DNA Damage; Humans; Lipid Peroxidation; Magnetic Resonance Spectroscopy; Microscopy, Electron, Transmission; Molecular Structure; Phenanthrolines; Taurochenodeoxycholic Acid; Thiourea; Transcription Factor CHOP

Calcium homeostasis plays a crucial role in neuronal development and disease. Calbindin-D. We used CaBP-9k knockout (KO) mice to investigate the roles of these gene in neurodegenerative diseases, such as Alzheimer's and Parkinson's diseases. We used anatomical and biochemical approaches to characterize functional abnormalities of the brain in the CaBP-9k KO mice.. We found that the brains of CaBP-9k KO mice have increased APP/β-amyloid, Tau, and α-synuclein accumulation and endoplasmic reticulum (ER) stress-induced apoptosis. Neurons deficient for these CaBP-9k had abnormal intracellular calcium levels and responses. ER stress inhibitor TUDCA reduced ER stress-induced apoptosis and restored ER stress- and apoptosis-related proteins expression to wild-type levels in CaBP-9k KO mice. Furthermore, treatment with TUDCA rescued the abnormal memory and motor behaviors exhibited by older CaBP-9k KO mice.. Our results suggest that a loss of CaBP-9k may contribute to the onset and progression of neurodegenerative diseases.

Topics: alpha-Synuclein; Alzheimer Disease; Amyloid beta-Peptides; Animals; Apoptosis; Brain; Calbindins; Calcium; Cell Proliferation; Cells, Cultured; Endoplasmic Reticulum Stress; Maze Learning; Memory Disorders; Mice; Mice, Knockout; Motor Activity; Neurons; Parkinson Disease; Risk Factors; RNA, Small Interfering; tau Proteins; Taurochenodeoxycholic Acid

Hepatic cytochrome P450 reductase (EC 1.6.2.4, POR) deficient mice provide a useful means of investigating liver-related CYP450 drug metabolism. However, the organ-wide inactivation of CYP450s has wide ranging effects on liver physiology. Untargeted UHPLC-MS metabolic and lipid profiling of aqueous and organic solvent extracts has been employed to compare the metabolic phenotypes of livers obtained from either wild type (C57Bl6) or hepatic P450 reductase null (HRN

Topics: Animals; Chromatography, High Pressure Liquid; Lipidomics; Liver; Male; Metabolomics; Mice; Mice, Inbred C57BL; Mice, Knockout; NADPH-Ferrihemoprotein Reductase; Phenotype; Phosphatidylcholines; Phosphatidylethanolamines; Taurochenodeoxycholic Acid

Tauroursodeoxycholic acid (TUDCA) is a US FDA-approved hydrophilic bile acid for the treatment of chronic cholestatic liver disease. In the present study, we investigate the effects of TUDCA on the proliferation and differentiation of osteoblasts and its therapeutic effect on a mice model of osteoporosis. Following treatment with different concentrations of TUDCA, cell viability, differentiation, and mineralization were measured. Three-month-old female C57BL/6 mice were randomly divided into three groups (n = 8 mice per group): (i) normal mice as the control group, (ii) ovariectomy (OVX) group (receiving phosphate-buffered saline (PBS) treatment every other day for 4 weeks), and (iii) OVX group with TUDCA (receiving TUDCA treatment every other day for 4 weeks starting 6 weeks after OVX). At 11 weeks post-surgery, serum levels of procollagen type I N-terminal propeptides (PINP) and type I collagen crosslinked C-telopeptides (CTX) were measured, and all mice were sacrificed to examine the distal femur by micro-computed tomography (CT) scans and histology. TUDCA (100 nM, 1 µM) significantly increased the proliferation and viability of osteoblasts and osteoblast differentiation and mineralization when used in vitro. Furthermore, TUDCA neutralized the detrimental effects of methylprednisolone (methylprednisolone-induced osteoblast apoptosis). In the TUDCA treatment group the PINP level was higher and the CTX level was lower, but these levels were not significantly different compared to the PBS treatment group. Micro-CT and histology showed that the TUDCA treatment group preserved more trabecular structures in the distal femur compared to the PBS treatment group. In addition, the TUDCA treatment group increased the percentage bone volume with respect to the total bone volume, bone mineral density, and mice distal femur trabeculae compared with the PBS treatment group. Taken together, our findings suggest that TUDCA may provide a favorable effect on bones and could be used for the prevention and treatment of osteoporosis.

Topics: Animals; Cell Differentiation; Cell Survival; Disease Models, Animal; Female; Gene Expression Regulation; Humans; Methylprednisolone; Mice; Osteoblasts; Osteoporosis; Ovariectomy; Peptide Fragments; Procollagen; Random Allocation; Taurochenodeoxycholic Acid; Treatment Outcome

We investigate the anti-inflammatory effects of injectable hydrogel containing tauroursodeoxycholic acid (TUDCA) in a spinal cord injury (SCI) model. To this end, TUDCA-hydrogel (TC gel) is created by immersing the synthesized hydrogel in a TUDCA solution for 1 h. A mechanical SCI was imposed on rats, after which we injected the TC gel. After the SCI and injections, motor functions and lesions were significantly improved in the TC gel group compared with those in the saline group. The TC gel significantly decreased pro-inflammatory cytokine levels compared with the saline; TUDCA and glycol chitosan-oxidized hyaluronate were mixed at a ratio of 9:1 (CHA) gel independently. In addition, the TC gel significantly suppressed the phosphorylation of extracellular signal-regulated kinase (p-ERK) and c-Jun N-terminal kinase (p-JNK) in the mitogen-activated protein kinase (MAPK) pathway compared with the saline, TUDCA, and CHA gel independently. It also decreased tumor necrosis factor-α (TNF-α) and glial fibrillary acidic protein (GFAP), inflammatory marker, at the injured sites more than those in the saline, TUDCA, and CHA gel groups. In conclusion, the results of this study demonstrate the neuroinflammatory inhibition effects of TC gel in SCI and suggest that TC gel can be an alternative drug system for SCI cases.

Topics: Animals; Anti-Inflammatory Agents; Apoptosis; Behavior, Animal; Chitosan; Cytokines; Glial Fibrillary Acidic Protein; Hyaluronic Acid; Hydrogels; Inflammation Mediators; Injections; MAP Kinase Signaling System; Motor Activity; Neuraminidase; Phosphorylation; Rats, Sprague-Dawley; Recovery of Function; Spinal Cord Injuries; Taurochenodeoxycholic Acid; Tumor Necrosis Factor-alpha

Impaired efferocytosis is a key mechanism of inflammatory lung diseases, including chronic obstructive pulmonary disease and cystic fibrosis. Cigarette smoking activates RhoA and impairs efferocytosis in alveolar macrophages, but the mechanism has not been fully elucidated. We investigated the role of endoplasmic reticulum (ER) stress induced by cigarette smoking in the disruption of efferocytosis. Both tunicamycin (10 μg/ml) and thapsigargin (0.1 and 1 μM), which are ER stress inducers, suppressed efferocytosis in J774 cells, and a Rho-associated coiled-coil-forming kinase (ROCK) inhibitor (Y27632) reversed this effect. We validated the effect of tunicamycin on efferocytosis in experiments using RAW264.7 cells. Then, we investigated the role of the unfolded protein response (UPR) in efferocytosis impaired by ER stress. A PERK inhibitor (GSK2606414) restored the efferocytosis that had been impaired by TM, and an eIF2α dephosphorylation inhibitor (salubrinal) suppressed efferocytosis. Cigarette smoke extract (CSE) induced ER stress in J774 macrophages and RhoA activation in J774 cells, and the CSE-induced ROCK activity was successfully reversed by GSK2606414 and tauroursodeoxycholic acid. Finally, we confirmed that ER stress suppresses efferocytosis in murine alveolar macrophages and that GSK2606414 could rescue this process. These data suggest that cigarette smoke-induced ER stress and the UPR play crucial roles in RhoA activation and suppression of efferocytosis in the lung.

Topics: Adenine; Animals; Cell Line; Cigarette Smoking; eIF-2 Kinase; Endoplasmic Reticulum Stress; Enzyme Activation; Eukaryotic Initiation Factor-2; Female; Indoles; Macrophages; Mice; Mice, Inbred ICR; Models, Biological; Phagocytosis; rho-Associated Kinases; rhoA GTP-Binding Protein; Signal Transduction; Taurochenodeoxycholic Acid; Tunicamycin

To determine local ocular tissue levels of the bile acid, tauroursodeoxycholic acid (TUDCA), in the pig model using oral, intravenous (IV), intravitreal injection (IVitI) and low- and high-dose suprachoroidal, sustained-release implants (SCI-L or SCI-H).. Forty-six pigs (92 globes) were included in the study. TUDCA was delivered orally in 5 pigs, IV in 4, IVitI in 6, SCI-L in 17, and SCI-H in 14. Testing timeframes varied from the same day (within minutes) for IV; 1 to 6 days, oral; and 1 to 4 weeks, IVitI and SCI. Enucleated globes were dissected, specimens from specific tissues were separated, and TUDCA was extracted and quantified using mass spectrometry.. The highest TUDCA tissue levels occurred after IV delivery in the macula (252 ± 238 nM) and peripheral retina (196 ± 171 nM). Macular choroid and peripheral choroid levels were also high (1032 ± 1269 and 1219 ± 1486 nM, respectively). For IVitI delivery, macular levels at day 6 were low (0.5 ± 0.5 nM), whereas peripheral choroid was higher (15.3 ± 16.7 nM). Neither the SCI-L nor SCI-H implants delivered meaningful macular doses (≤1 nM); however, peripheral retina and choroid levels were significantly higher. Bile acid isoforms were found in the serum specimens.. The highest TUDCA tissue levels in the pig model were obtained using IV delivery. Oral delivery was associated with reasonable tissue levels. Local delivery (IVitI and SCI) was able to achieve measurable local ocular tissue levels.. Diffusional kinetics from the suprachoroidal space follow the choroidal blood flow, away from the macula and toward the periphery.

Topics: Animals; Choroid; Intravitreal Injections; Pharmaceutical Preparations; Swine; Taurochenodeoxycholic Acid; Tissue Distribution

Intracerebral hemorrhage (ICH) is a form of stroke, characterized by high morbidity and mortality and currently lacks specific therapy. ICH leads to endoplasmic reticulum (ER) stress, which can induce neurological impairment through crosstalk with programmed cell death (PCD). Pyroptosis, a newly discovered form of PCD, has received attention because of its close relationship with some certain diseases, such as traumatic brain injury and ischemic and hemorrhagic stroke. However, the relationship between ER stress and pyroptosis in ICH remains unclear. In this study, we investigated the role of ER stress in evoking neuronal pyroptosis and related mechanisms in a mouse ICH model. We used tauroursodeoxycholic acid (TUDCA) to inhibit ER stress and observed that TUDCA reduces neuronal pyroptosis and has a neuroprotective role. We explored the potential mechanisms underlying the regulation of neuronal pyroptosis by ER stress through testing the expression of interleukin-13 (IL-13). We found that ER stress inhibition alleviates neuronal pyroptosis through decreasing the expression of IL-13 after ICH. In summary, this study revealed that IL-13 is involved in ER stress-induced neuronal pyroptosis after ICH, pointing to IL-13 as a novel therapeutic target for ICH treatment.

Topics: Animals; Brain Edema; Cell Membrane; Cerebral Hemorrhage; Collagenases; Disease Models, Animal; Endoplasmic Reticulum Stress; Interleukin-13; Male; Mice, Inbred C57BL; Models, Biological; Motor Activity; Neurons; Neuroprotective Agents; Pyroptosis; Spatial Memory; Stroke; Taurochenodeoxycholic Acid

Opioids are potent analgesics widely used to control acute and chronic pain, but long-term use induces tolerance that reduces their effectiveness. Opioids such as morphine bind to mu opioid receptors (MORs), and several downstream signaling pathways are capable of inducing tolerance. We previously reported that signaling from the endoplasmic reticulum (ER) contributed to the development of morphine tolerance. Accumulation of misfolded proteins in the ER induced the unfolded protein response (UPR) that causes diverse pathological conditions. We examined the effects of pharmacological chaperones that alleviate ER stress on opioid tolerance development by assessing thermal nociception in mice. Pharmacological chaperones such as tauroursodeoxycholic acid and 4-phenylbutyrate suppressed the development of morphine tolerance and restored analgesia. Chaperones alone did not cause analgesia. Although morphine administration induced analgesia when glycogen synthase kinase 3β (GSK3β) was in an inactive state due to serine 9 phosphorylation, repeated morphine administration suppressed this phosphorylation event. Co-administration of chaperones maintained the inactive state of GSK3β. These results suggest that ER stress may facilitate morphine tolerance due to intracellular crosstalk between the UPR and MOR signaling. Pharmacological chaperones may be useful in the management of opioid misuse.

Topics: Analgesics, Opioid; Animals; Drug Tolerance; Endoplasmic Reticulum Stress; Glycogen Synthase Kinase 3 beta; Male; Mice; Mice, Inbred C57BL; Morphine; Nociception; Phenylbutyrates; Taurochenodeoxycholic Acid

Paraquat (PQ), a widely used herbicide, could cause neurodegenerative diseases, yet the mechanism remains incompletely understood. This study aimed to investigate the direct effect of PQ on NSC in vivo and its possible mechanism. Adult C57BL/6 mice were subcutaneously injected with 2 mg/kg PQ, 20 mg/kg PQ or vehicle control once a week for 2 weeks, and sacrificed 1 week after the last PQ injection. Furthermore, extra experiments with Tauroursodeoxycholic Acid (TUDCA) intervention were performed to observe the relationship between ER stress, neuroinflammation and the neural stem cell (NSC) impairment. The results showed that 20 mg/kg PQ caused the NSC number decrease in both subgranular zones (SGZ) and subventricular zone (SVZ). Further analysis indicated that the 20 mg/kg PQ suppressed the proliferation of NSC, without affecting the apoptosis. Moreover, 20 mg/kg PQ also induced ER stress in microglia and caused neuroinflammation in SGZ and SVZ. Interestingly, the ER stress inhibitor could simultaneously ameliorate the neuroinflammation and NSC reduction. These data suggested that increased ER stress in microglia might be a possible pathway for PQ-induced neuroinflammation and NSC impairment. That is a previously unknown mechanism for PQ neurotoxicity.

Topics: Animals; Apoptosis; Endoplasmic Reticulum Stress; Herbicides; Inflammation; Lateral Ventricles; Mice; Microglia; Neural Stem Cells; Paraquat; Taurochenodeoxycholic Acid

The P2Y12 receptor is an adenosine diphosphate responsive G protein-coupled receptor expressed on the surface of platelets and is the pharmacologic target of several anti-thrombotic agents. In this study, we use liver samples from mice with cirrhosis and hepatocellular carcinoma to show that P2Y12 is expressed by macrophages in the liver. Using in vitro methods, we show that inhibition of P2Y12 with ticagrelor enhances tumor cell phagocytosis by macrophages and induces an anti-tumoral phenotype. Treatment with ticagrelor also increases the expression of several actors of the endoplasmic reticulum (ER) stress pathways, suggesting activation of the unfolded protein response (UPR). Inhibiting the UPR with tauroursodeoxycholic acid (Tudca) diminishes the pro-phagocytotic effect of ticagrelor, thereby indicating that P2Y12 mediates macrophage function through activation of ER stress pathways. This could be relevant in the pathogenesis of chronic liver disease and cancer, as macrophages are considered key players in these inflammation-driven pathologies.

Topics: Animals; Cell Line, Tumor; Cholagogues and Choleretics; Endoplasmic Reticulum Stress; Humans; Liver Cirrhosis, Experimental; Liver Neoplasms, Experimental; Macrophages; Male; Mice; Mice, Inbred C57BL; Purinergic P2Y Receptor Antagonists; Receptors, Purinergic P2Y12; Taurochenodeoxycholic Acid; Ticagrelor; Unfolded Protein Response

Neuronal apoptosis plays a critical event in the pathogenesis of early brain injury after subarachnoid hemorrhage (SAH). This study investigated the roles of Tauroursodeoxycholic acid (TUDCA) in attenuate neuronal apoptosis and underlying mechanisms after SAH.. Sprague-Dawley rats were subjected to model of SAH and TUDCA was administered via the internal carotid injection. Small interfering RNA (siRNA) for TGR5 were administered through intracerebroventricular injection 48 h before SAH. Neurological scores, brain water content, Western blot, TUNEL staining and immunofluorescence staining were evaluated.. TUDCA alleviated brain water content and improved neurological scores at 24 h and 72 h after SAH. TUDCA administration prevented the reduction of SIRT3 and BCL-2 expressions, as well as the increase of BAX and cleaved caspase-3.Endogenous TGR5 expression were upregulated after SAH and treatment with TGR5 siRNA exacerbated neurological outcomes after SAH and the protective effects of TUDCA at 24 h after SAH were also abolished by TGR5 siRNA.. Our findings demonstrate that TUDCA could attenuated neuronal apoptosis and improve neurological functions through TGR5/ SIRT3 signaling pathway after SAH. TUDCA may be an attractive candidate for anti-apoptosis treatment in SAH.

Topics: Animals; Apoptosis; Male; Neurons; Rats; Rats, Sprague-Dawley; Receptors, G-Protein-Coupled; Sirtuins; Subarachnoid Hemorrhage; Taurochenodeoxycholic Acid

The aim of this study was to investigate the changes of bile acids in the liver during hemorrhagic shock (HS) and their potential to attenuate liver injury via activation of SIRT1 (sirtuin 1)-FXR (farnesoid X receptor) signaling.. A Sprague-Dawley (SD) rat HS model was established, whereas HepG2 cells were hypoxically cultured to simulate HS in vitro. Liver bile acids (BA) were profiled with ultraperformance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). FXR expression was detected by western blot and immunohistochemistry. The mRNA levels of SIRT1 and FXR were detected by polymerase chain reaction. Protein expression of SIRT1, FoxM1, NF-κB, acetyl-NF-κB, p53, and acetyl-p53 was analyzed by western blot. Hepatocyte apoptosis and proliferation were measured by TUNEL assay and Ki-67 staining, respectively. Serum and supernatant cytokines were analyzed using ELISA assays. Liver injury was also assessed. To investigate the possible mechanisms, SIRT1 agonist (SRT1720), SIRT1 inhibitor (EX527), and FXR inhibitor (Z-guggulsterone) were used.. Tauroursodeoxycholic acid (TUDCA) in the liver decreased significantly after HS. SIRT1 and FXR expression was time-dependently downregulated by HS or hypoxia condition. TUDCA upregulated SIRT1-FXR activity, which inhibited expression and acetylation of NF-κB and p53 and increased FoxM1 expression, leading to decreased inflammatory response and apoptosis and increased proliferative capacity in hepatocytes, and attenuation of liver injury. EX527 pretreatment reversed the protective effect of TUDCA. Moreover, Z-guggulsterone supplementation decreased the protective effect of TUDCA in vitro.. TUDCA in the liver decreased during HS. TUDCA supplementation might attenuate HS-induced liver injury by upregulating SIRT1-FXR signaling.

Topics: Animals; Forkhead Box Protein M1; Hep G2 Cells; Humans; Liver; NF-kappa B; Rats; Rats, Sprague-Dawley; Shock, Hemorrhagic; Signal Transduction; Sirtuin 1; Taurochenodeoxycholic Acid; Tumor Suppressor Protein p53

Xerostomia in SS patients has been associated with low quality and quantity of salivary mucins, which are fundamental for the hydration and protection of the oral mucosa. The aim of this study was to evaluate if cytokines induce aberrant mucin expression and whether tauroursodeoxycholic acid (TUDCA) is able to counteract such an anomaly.. Labial salivary glands from 16 SS patients and 15 control subjects, as well as 3D acini or human submandibular gland cells stimulated with TNF-α or IFN-γ and co-incubated with TUDCA, were analysed. mRNA and protein levels of Mucin 1 (MUC1) and MUC7 were determined by RT-qPCR and western blot, respectively. Co-immunoprecipitation and immunofluorescence assays for mucins and GRP78 [an endoplasmic reticulum (ER)-resident protein] were also performed. mRNA levels of RelA/p65 (nuclear factor-κB subunit), TNF-α, IL-1β, IL-6, SEL1L and EDEM1 were determined by RT-qPCR, and RelA/p65 localization was evaluated by immunofluorescence.. MUC1 is overexpressed and accumulated in the ER of labial salivary gland from SS patients, while MUC7 accumulates throughout the cytoplasm of acinar cells; however, MUC1, but not MUC7, co-precipitated with GRP78. TUDCA diminished the overexpression and aberrant accumulation of MUC1 induced by TNF-α and IFN-γ, as well as the nuclear translocation of RelA/p65, together with the expression of inflammatory and ER stress markers in 3D acini.. Chronic inflammation alters the secretory process of MUC1, inducing ER stress and affecting the quality of saliva in SS patients. TUDCA showed anti-inflammatory properties decreasing aberrant MUC1 accumulation. Further studies are necessary to evaluate the potential therapeutic effect of TUDCA in restoring glandular homeostasis in SS patients.

Topics: Acinar Cells; Adult; Aged; Case-Control Studies; Cells, Cultured; Endoplasmic Reticulum Chaperone BiP; Endoplasmic Reticulum Stress; Female; Heat-Shock Proteins; Humans; Immunoprecipitation; In Vitro Techniques; Interferon-gamma; Interleukin-1beta; Interleukin-6; Male; Membrane Proteins; Middle Aged; Mucin-1; Mucins; Proteins; RNA, Messenger; Salivary Glands, Minor; Salivary Proteins and Peptides; Sjogren's Syndrome; Submandibular Gland; Taurochenodeoxycholic Acid; Transcription Factor RelA; Tumor Necrosis Factor-alpha; Xerostomia; Young Adult

Myocardial ischaemia/reperfusion (I/R) produces structural and functional alterations depending on the duration of ischaemia. Brief ischaemia followed by reperfusion causes reversible contractile dysfunction (stunned heart) but long-lasting ischaemia followed by reperfusion can result in irreversible injury with cell death. Events during I/R can alter endoplasmic reticulum (ER) function leading to the accumulation of unfolded/misfolded proteins. The resulting ER stress induces activation of several signal transduction pathways, known as unfolded protein response (UPR). Experimental evidence shows that UPR contributes to cell death in irreversible I/R injury; however, there is still uncertainty for its occurrence in the stunned myocardium. This study investigated the ER stress response and its functional impact on the post-ischaemic cardiac performance of the stunned heart.. Perfused rat hearts were subjected to 20 minutes of ischaemia followed by 30 minutes of reperfusion. UPR markers were evaluated by qRT-PCR and western blot. Post-ischaemic mechanical recovery was measured in absence and presence of two chemical chaperones: tauroursodeoxycholic acid (TUDCA) and 4-phenylbutyric acid (4-PBA).. Analysis of mRNA and protein levels of various ER stress effectors demonstrated that different UPR signalling cascades, involving both pro-survival and pro-apoptotic pathways, are activated. Inhibition of the UPR with chemical chaperones improved the post-ischaemic recovery of cardiac mechanical function without affecting the I/R-induced increase in oxidative stress.. Our results suggest that prevention of ER stress by chemical chaperones could be a therapeutic tool to limit deterioration of the contractile function in clinical settings in which the phenomenon of myocardial stunning is present.

Topics: Animals; Antineoplastic Agents; Apoptosis; Cholagogues and Choleretics; Disease Models, Animal; Endoplasmic Reticulum Stress; Heat-Shock Proteins; Male; Myocardial Reperfusion Injury; Myocardial Stunning; Myocardium; Phenylbutyrates; Rats; Rats, Wistar; Signal Transduction; Taurochenodeoxycholic Acid; Unfolded Protein Response

Polyhexamethyleneguanidine phosphate (PHMG-P) is a widely used polymeric antimicrobial agent known to induce significant pulmonary toxicity. Several studies have reported that the liver also can be a target organ of polyhexamethyleneguanidine (PHMG) toxicity, but the exact effect of this compound on liver cells is not well understood. To identify the mechanism of PHMG hepatotoxicity, HepG2 cells were exposed to PHMG-P for 72 h. The cell viability was significantly decreased by PHMG-P in a time- and concentration-dependent manner. The mitochondrial membrane potential was markedly reduced by PHMG-P and the apoptotic signaling cascade was activated. The increases observed in C/EBP homologous protein (CHOP), p-IRE, and p-JNK levels in PHMG-P-treated cells indicated the induction of endoplasmic reticulum stress. To verify the role of ER stress in PHMG-P-induced cytotoxicity, HepG2 cells were pretreated with the chemical chaperone, tauroursodeoxycholic acid (TUDCA) and then co-treated with TUDCA and PHMG-P for 24 h. Interestingly, TUDCA inhibited PHMG-P-induced ER stress and cytotoxicity in a dose-dependent manner. The apoptotic cell death and mitochondrial depolarization were also prevented by TUDCA. The proteins involved in the apoptotic pathway were all normalized to their control levels in TUDCA-treated cells. In conclusion, the results suggest that PHMG-P induced significant cytotoxicity in liver cells and ER stress-mediated apoptosis, which may be an important mechanism mediating this hepatotoxicity.

Topics: Animals; Apoptosis; Calcium-Binding Proteins; Cells, Cultured; Endoplasmic Reticulum Stress; Guanidines; Hep G2 Cells; Hepatocytes; Humans; MAP Kinase Kinase 4; Mice; Mitochondria, Liver; Taurochenodeoxycholic Acid

Endoplasmic reticulum stress (ERS) has been shown to play a crucial role in the pathogenesis of hypertension. However, the role and mechanisms of ERS on hypertension-induced cardiac functional and morphological changes remain unclear. In this study, the effect of ERS inhibition with tauroursodeoxycholic acid (TUDCA) on hypertension-induced cardiac remodelling was examined.. Hypertension was induced by deoxycorticosterone-acetate (DOCA) and salt administration in uni-nephrectomized rats for 12 weeks. TUDCA was administered for the last four weeks. Rhythmic activity and contractions of the right atrium and left papillary muscle (LPM) were recorded. In the left ventricle, the expression of various proteins was examined and histopathological evaluation was performed.. Hypertension-induced increments in systolic blood pressure and ventricular contractions were reversed by TUDCA. In the hypertensive heart, while expressions of glucose-regulated protein-78 (GRP78), phospho-dsRNA-activated protein kinase-like ER kinase (p-PERK), sarcoplasmic reticulum Ca-ATPase-2 (SERCA2), matrix metalloproteinase-2 (MMP-2) and nuclear NF-κB p65 increased; Bcl-2 (B-cell lymphoma-2) expression decreased and the altered levels of all these markers were restored by TUDCA. In the microscopic examination, TUDCA treatment attenuated hypertension-stimulated cardiac inflammation and fibrosis.. These results suggest that ERS inhibition may ameliorate cardiac contractility through improving ERS-associated calcium mishandling, apoptosis, inflammation and fibrosis, thereby offering therapeutic potential in hypertension-induced cardiac dysfunction.

Topics: Animals; Apoptosis; Blood Pressure; Calcium; Desoxycorticosterone Acetate; Disease Models, Animal; Endoplasmic Reticulum Stress; Fibrosis; Hypertension; Inflammation; Male; Rats; Rats, Wistar; Taurochenodeoxycholic Acid

Topics: Animals; Cell Line; Cell Survival; Diabetes Mellitus, Type 1; Endoplasmic Reticulum Stress; Insulin-Secreting Cells; Mice; Mice, Knockout; S100 Calcium Binding Protein G; Taurochenodeoxycholic Acid; Thapsigargin

We recently reported that a treatment with tauroursodeoxycholic acid (TUDCA), a secondary bile acid, improved developmentally-deteriorated hepatic steatosis in an undernourishment (UN, 40% caloric restriction) in utero mouse model after a postnatal high-fat diet (HFD). We performed a microarray analysis and focused on two genes (Cidea and Cidec) because they are enhancers of lipid droplet (LD) sizes in hepatocytes and showed the greatest up-regulation in expression by UN that were completely recovered by TUDCA, concomitant with parallel changes in LD sizes. TUDCA remodeled developmentally-induced histone modifications (dimethylation of H3K4, H3K27, or H3K36), but not DNA methylation, around the Cidea and Cidec genes in UN pups only. Changes in these histone modifications may contribute to the markedly down-regulated expression of Cidea and Cidec genes in UN pups, which was observed in the alleviation of hepatic fat deposition, even under HFD. These results provide an insight into the future of precision medicine for developmentally-programmed hepatic steatosis by targeting histone modifications.

Topics: Animals; Apoptosis Regulatory Proteins; Cholagogues and Choleretics; Diet, High-Fat; Fatty Liver; Gene Expression Profiling; Gene Expression Regulation, Developmental; Histone Code; Male; Mice; Mice, Inbred C57BL; Protein Processing, Post-Translational; Proteins; Taurochenodeoxycholic Acid

Pseudorabies virus (PRV) infection causes great economic losses in the pig industry. By disrupting the homeostasis of the endoplasmic reticulum (ER), many viral infections induce ER stress and trigger the unfolded protein response (UPR). However, the roles of ER stress and UPR in PRV infection remain unclear. In the present study, we demonstrate that the expression of the ER stress marker glucose-regulated protein 78 (GRP78) increased during the early stages of PRV infection, indicating that ER stress was induced. Examination of the three branches of the UPR revealed that the IRE1-XBP1 and eIF2α-ATF4 pathways were activated during PRV infection. In addition, PRV induced apoptosis in later stages of infection through the CHOP-Bcl2 axis. Overexpression of GRP78 or ER stress inducer treatment with thapsigargin could enhance PRV production. Conversely, ER stress inhibitor treatment with tauroursodeoxycholic acid reduced PRV replication. Taken together, our results reveal that PRV infection induces ER stress and activates the IRE1-XBP1 and eIF2α-ATF4 pathways.

Topics: Animals; Antiviral Agents; Cell Line; Endoplasmic Reticulum Chaperone BiP; Endoplasmic Reticulum Stress; Gene Expression Regulation; Heat-Shock Proteins; Pseudorabies; Signal Transduction; Swine; Taurochenodeoxycholic Acid; Unfolded Protein Response; Virus Replication

Recent evidence has identified a role of micronutrients, such as magnesium (Mg

Topics: Animals; Calcium; Diabetes Mellitus, Type 1; Heart; Kidney; Liver; Magnesium; Male; Mice; Myocardium; Phenylbutyrates; Spleen; Streptozocin; Taurochenodeoxycholic Acid

c-Myc plays a major role in the maintenance of glycolytic metabolism and hematopoietic stem cell (HSC) quiescence.. Targeting modulators of HSC quiescence and metabolism could lead to HSC cell cycle entry with concomitant expansion.. Here we show that c-Myc inhibitor 10074-G5 treatment leads to 2-fold increase in murine LSKCD34low HSC compartment post 7 days. In addition, c-Myc inhibition increases CD34+ and CD133+ human HSC number. c-Myc inhibition leads to downregulation of glycolytic and cyclindependent kinase inhibitor (CDKI) gene expression ex vivo and in vivo. In addition, c-Myc inhibition upregulates major HDR modulator Rad51 expression in hematopoietic cells. Besides, c-Myc inhibition does not alter proliferation kinetics of endothelial cells, fibroblasts or adipose-derived mesenchymal stem cells, however, it limits bone marrow derived mesenchymal stem cell proliferation. We further demonstrate that a cocktail of c-Myc inhibitor 10074-G5 along with tauroursodeoxycholic acid (TUDCA) and i-NOS inhibitor L-NIL provides a robust HSC maintenance and expansion ex vivo as evident by induction of all stem cell antigens analyzed. Intriguingly, the cocktail of c-Myc inhibitor 10074-G5, TUDCA and L-NIL improves HDR related gene expression.. These findings provide tools to improve ex vivo HSC maintenance and expansion, autologous HSC transplantation and gene editing through modulation of HSC glycolytic and HDR pathways.

Topics: Animals; Antiviral Agents; Apoptosis; Cell Culture Techniques; Cell Cycle; Cell Differentiation; Cell Proliferation; Cells, Cultured; Enzyme Inhibitors; Hematopoietic Stem Cells; Humans; Lysine; Mice; Mice, Inbred BALB C; Mice, SCID; Nitric Oxide Synthase; Oxadiazoles; Proto-Oncogene Proteins c-myc; Rad51 Recombinase; Small Molecule Libraries; Taurochenodeoxycholic Acid

Inflammatory bowel diseases is associated with an increased risk for the development of colorectal cancer. However, the mechanism of immune signaling pathways linked to colitis-associated cancer (CAC) has not been fully elucidated. Tauroursodeoxycholic acid (TUDCA) exhibits anti-inflammatory and anti-cancer activities. The aim of this study is to investigate the role of TUDCA in the pathogenesis of CAC.. Colitis-associated cancer was induced in mice using azoxymethane and dextran sodium sulfate administration, and TUDCA's effect on tumor development was evaluated. HCT 116 and COLO 205 were treated with TUDCA or vehicle and then stimulated with tumor necrosis factor-α (TNF-α). Expression of interleukin (IL)-8 was determined by real-time reverse transcription-polymerase chain reaction and enzyme-linked immunosorbent assay, and IκBα phosphorylation and degradation was evaluated by immunoblot assay. The DNA-binding activity of NF-κB was assessed by electrophoretic mobility shift assay. Cell viability assay and real-time reverse transcription-polymerase chain reaction of bcl-xL, MCL1, c-FLIP-L, and VEGF were performed.. Tauroursodeoxycholic acid significantly attenuated the development of CAC in mice. Exposure to TUDCA resulted in extensive epithelial apoptosis and reduced levels of phospho-IκB kinase in the colon. In HCT 116 cells stimulated with TNF-α, TUDCA significantly inhibited IL-8 and IL-1α expression and suppressed TNF-α-induced IκBα phosphorylation/degradation and DNA-binding activity of NF-κB. Furthermore, in both HCT 116 and COLO 205 cells, TUDCA reduced cell viability and downregulated the expression of bcl-xL, MCL1, c-FLIP-L, and VEGF.. These results demonstrated that TUDCA suppresses NF-κB signaling and ameliorates colitis-associated tumorigenesis, suggesting that TUDCA could be a potential treatment for CAC.

Topics: Animals; Apoptosis; Colitis; Colon; Colorectal Neoplasms; Interleukin-1alpha; Interleukin-8; Male; Mice, Inbred C57BL; NF-kappa B; Signal Transduction; Taurochenodeoxycholic Acid; Tumor Cells, Cultured

Patients with idiopathic pulmonary fibrosis (IPF) often experience acute exacerbation (AE) after an episode of common cold.. To establish a mouse model of virus infection-induced AE-IPF and investigate the mechanism underlying the AE-IPF.. Herpes simplex virus 1 (HSV1) was inoculated intranasally to wild-type (WT) and IL-17A gene knockout (IL-17A. HSV1 infection caused acute exacerbation in mice with BLM-induced fibrosis. Compared with the BLM+Saline mice, the mice with BLM+HSV1 showed significantly higher acute lung injury (ALI) score (P < 0.0001), lower survival rate (100% vs 21.4%, P < 0.0001), poorer lung function and higher inflammatory response representing by increased total inflammatory cells in bronchoalveolar lavage fluid (BALF) (P = 0.0323), increased proportion of Th17 cells in peripheral blood (P = 0.0004) and higher inflammatory factors in BALF. In addition, HSV1 infection increased the expression of endoplasmic reticulum stress (ERS)-related proteins in mice with BLM-induced fibrosis. The inhibition of ERS by tauroursodeoxycholic acid (TUDCA, an ERS inhibitor) significantly reduced the IL-17A levels in BALF (P = 0.0140) and TH17 cells in the peripheral blood (P = 0.0084) of mice with BLM+HSV1, suggesting that suppression of ERS may reduce TH17 response in mice with AE-IPF. Compared with WT mice with BLM+HSV1, IL-17A. HSV1 infection in addition to BLM-induced IPF can successfully establish AE-IPF in mice. IL-17A and ERS promote lung inflammation in AE-IPF development.

Topics: Acute Lung Injury; Animals; Anti-Inflammatory Agents; Antiviral Agents; Bleomycin; Bronchoalveolar Lavage Fluid; Disease Models, Animal; Endoplasmic Reticulum Stress; Gene Expression; Herpes Simplex; Herpesvirus 1, Human; Humans; Idiopathic Pulmonary Fibrosis; Interleukin-17; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Respiratory Function Tests; Survival Analysis; Taurochenodeoxycholic Acid; Th17 Cells

As a consequence of impaired glucose or fatty acid metabolism, bioenergetic stress in skeletal muscles may trigger myopathy and rhabdomyolysis. Genetic mutations causing loss of function of the LPIN1 gene frequently lead to severe rhabdomyolysis bouts in children, though the metabolic alterations and possible therapeutic interventions remain elusive. Here, we show that lipin1 deficiency in mouse skeletal muscles is sufficient to trigger myopathy. Strikingly, muscle fibers display strong accumulation of both neutral and phospholipids. The metabolic lipid imbalance can be traced to an altered fatty acid synthesis and fatty acid oxidation, accompanied by a defect in acyl chain elongation and desaturation. As an underlying cause, we reveal a severe sarcoplasmic reticulum (SR) stress, leading to the activation of the lipogenic SREBP1c/SREBP2 factors, the accumulation of the Fgf21 cytokine, and alterations of SR-mitochondria morphology. Importantly, pharmacological treatments with the chaperone TUDCA and the fatty acid oxidation activator bezafibrate improve muscle histology and strength of lipin1 mutants. Our data reveal that SR stress and alterations in SR-mitochondria contacts are contributing factors and potential intervention targets of the myopathy associated with lipin1 deficiency.

Topics: Animals; Endoplasmic Reticulum Stress; Lipid Metabolism; Male; Mice; Mice, Transgenic; Mitochondria, Muscle; Molecular Chaperones; Muscle, Skeletal; Muscular Diseases; Phosphatidate Phosphatase; Sarcoplasmic Reticulum; Taurochenodeoxycholic Acid

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease selectively targeting motor neurons in the brain and spinal cord. The reasons for differential motor neuron susceptibility remain elusive. We developed a stem cell-based motor neuron assay to study cell-autonomous mechanisms causing motor neuron degeneration, with implications for ALS. A small-molecule screen identified cyclopiazonic acid (CPA) as a stressor to which stem cell-derived motor neurons were more sensitive than interneurons. CPA induced endoplasmic reticulum stress and the unfolded protein response. Furthermore, CPA resulted in an accelerated degeneration of motor neurons expressing human superoxide dismutase 1 (hSOD1) carrying the ALS-causing G93A mutation, compared to motor neurons expressing wild-type hSOD1. A secondary screen identified compounds that alleviated CPA-mediated motor neuron degeneration: three kinase inhibitors and tauroursodeoxycholic acid (TUDCA), a bile acid derivative. The neuroprotective effects of these compounds were validated in human stem cell-derived motor neurons carrying a mutated SOD1 allele (hSOD1

Topics: Animals; Cells, Cultured; Disease Models, Animal; Endoplasmic Reticulum Stress; Humans; Indoles; Mice; Motor Neurons; Mutation; Stem Cells; Superoxide Dismutase-1; Taurochenodeoxycholic Acid

Hypertension has complex vascular pathogenesis and therefore the molecular etiology remains poorly elucidated. Endoplasmic reticulum stress (ERS), which is a condition of the unfolded/misfolded protein accumulation in the endoplasmic reticulum, has been defined as a potential target for cardiovascular disease. In the present study, the effects of ERS inhibition on hypertension-induced alterations in the vessels were investigated. In male Wistar albino rats, hypertension was induced through unilateral nephrectomy, deoxycorticosterone-acetate (DOCA) injection (20 mg/kg, twice a week) and 1% NaCl with 0.2% KCI added to drinking water for 12 weeks. An ERS inhibitor, tauroursodeoxycolic acid (TUDCA) (150 mg/kg/day, i.p.), was administered for the final four weeks. ERS inhibition in DOCA-salt induced hypertension was observed to have reduced systolic blood pressure, improved endothelial dysfunction, enhanced plasma nitric oxide (NO) level, reduced protein expressions of phosphorylated-double-stranded RNA-activated protein kinase-like endoplasmic reticulum kinase (pPERK), 78 kDa glucose-regulated protein (GRP78), Inositol trisphosphate receptor1 (IP

Topics: Animals; Antihypertensive Agents; Aorta, Thoracic; Apoptosis; Blood Pressure; Calcium; Cell Proliferation; Desoxycorticosterone Acetate; Disease Models, Animal; eIF-2 Kinase; Endoplasmic Reticulum Stress; ErbB Receptors; Extracellular Signal-Regulated MAP Kinases; Heat-Shock Proteins; Hypertension; Inositol 1,4,5-Trisphosphate Receptors; Male; Nephrectomy; NF-KappaB Inhibitor alpha; Nitric Oxide; Phosphorylation; Proto-Oncogene Proteins c-bcl-2; Rats, Wistar; Sarcoplasmic Reticulum Calcium-Transporting ATPases; Signal Transduction; Sodium Chloride, Dietary; Taurochenodeoxycholic Acid

Impaired function of the endoplasmic reticulum (ER) results in ER stress, an accumulation of proteins in the ER lumen. ER stress is a major contributor to inflammatory diseases and is part of the pathomechanism of ischemia-reperfusion injury (IRI). Since severe traumatic injury is often accompanied by remote organ damage and immune cell dysfunction, we investigated the influence of ER stress modulation on the systemic inflammatory response and liver damage after hemorrhagic shock and reperfusion (HS/R).. Male C56BL/6-mice were subjected to hemorrhagic shock with a mean arterial pressure of 30 ± 5 mm Hg. After 90 min mice were resuscitated with Ringer solution. Either the ER stress inductor tunicamycin (TM), its drug vehicle (DV), or the ER stress inhibitor tauroursodeoxycholic acid (TUDCA) were added to reperfusion solution. Animals were sacrificed 14 h after shock induction and plasma concentrations of liver transaminases as well as inflammatory cytokines were measured. In addition, liver tissue sections were embedded in paraffin. For the quantification of hepatocellular damage hematoxylin and eosin stained tissue sections were analyzed. Furthermore, the topographic patterns of ER stress marker proteins were evaluated using immunohistochemistry.. ER stress modulation influenced the topographic pattern of ER stress marker proteins. The alterations were particularly seen in the transition zone between vital liver parenchyma and cell death areas. Furthermore, the application of tunicamycin during reperfusion inhibited the secretion of pro-inflammatory cytokines and increased the hepatocellular damage significantly. However, the injection of TUDCA resulted in a significantly reduced liver damage, as seen by lower transaminases and smaller cell death areas.. ER stress modulation influences post-hemorrhagic IRI. Moreover, the ER stress inhibitor TUDCA diminished the hepatocellular damage following HS/R significantly. This may help to provide a therapeutic target to ameliorate the clinical outcome after trauma-hemorrhage.

Topics: Animals; Endoplasmic Reticulum Stress; Liver; Liver Diseases; Male; Mice; Reperfusion Injury; Shock, Hemorrhagic; Taurochenodeoxycholic Acid

Chronic high salt intake exaggerates renal injury and inflammation, especially with the loss of functional ET. In ET. TUDCA protects against the development of glomerular and proximal tubular damage, decreases renal cell death and inflammation in the renal cortex in rats with ET

Topics: Animals; Animals, Genetically Modified; Gene Deletion; Inflammation; Kidney Diseases; Male; Random Allocation; Rats; Receptor, Endothelin B; Sodium Chloride, Dietary; Taurochenodeoxycholic Acid

Depression is a mental disease that causes severe economic and social burdens. The mechanism for the onset of depression remains largely unknown. Recently, more and more attention is being given to the role of neuroinflammation and oxidative stress in depression. Tauroursodeoxycholic acid (TUDCA), a clinically available agent used to treat cholesterol gallstone and protect neurons against neurodegeneration, has been reported to prevent neuroinflammation and oxidative stress. In this study, we investigated the effect of TUDCA on lipopolysaccharide (LPS)-induced depression-like behavior, neuroinflammation, and oxido-nitrosative stress in mice. Results showed that TUDCA pretreatment (once daily for 7 consecutive days) at the dosage of 200 and 400 mg/kg, but not 100 mg/kg, markedly attenuated LPS (0.83 mg/kg)-induced behavioral abnormalities in the tail suspension test, forced swim test, and sucrose preference test. Further analysis showed that the TUDCA pretreatment (200, 400 mg/kg) not only inhibited the production of proinflammatory cytokines induced by LPS stimulation, such as interleukin-6 and tumor necrosis factor-α, but attenuated LPS-triggered oxido-nitrosative stress in the hippocampus and prefrontal cortex. Taken together, our results provide evidence to show that the TUDCA could be a potential antidepressant, and its antidepressive mechanism may be associated with the inhibition of the neuroinflammatory response and oxido-nitrosative stress in the brain.

Topics: Animals; Antidepressive Agents; Cytokines; Depression; Disease Models, Animal; Fluoxetine; Hippocampus; Inflammation; Interleukin-6; Lipopolysaccharides; Male; Mice; Mice, Inbred ICR; Nitrosative Stress; Oxidative Stress; Prefrontal Cortex; Taurochenodeoxycholic Acid; Tumor Necrosis Factor-alpha

It has been well established that HMG-CoA reductase inhibitors (statins) cause adverse side effects in skeletal muscle ranging from mild to fatal myotoxicity upon dose, drug interaction, and exercise. However, the underlying mechanisms by which statins induce myotoxicity have not been fully addressed. Recent reports showed that statins induce endoplasmic reticulum (ER) stress and cell death in immune cells and myoblasts in vitro. Therefore, the goal of study is to investigate the molecular mechanism by which statins induce skeletal muscle cell death and myopathy via the regulation of ER stress. Biochemical data showed that TUDCA, an ER stress inhibitor, inhibited atorvastatin- and simvastatin-induced protein cleavages of PARP-1 and caspase-3, respectively. Actually, statin treatment activated marker proteins of unfolded protein responses (UPR) including ATF6, CHOP, and spliced XBP1 and these responses were inhibited by TUDCA. In addition, statin treatment induced mRNA levels of UPR marker genes, suggesting that statins activate ER stress in a transcriptional regulation. The physiological relevance of ER stress in statin-induced myopathy was demonstrated in a mouse model of myopathy, in which instillation of simvastatin and atorvastatin led to myopathy. Notably, the reduction of muscular endurance in response to statin instillation was significantly improved in TUDCA treating group compared to vehicle control group. Moreover, CHOP deficiency mice showed restoration of statin-induced reduction of muscular endurance, suggesting that statin induces myopathy via ER stress and in a CHOP-dependent manner. Taken together, these findings indicate that statins specifically induce myopathy in an ER stress-dependent manner, suggesting the therapeutic potential of ER stress regulation in preventing adverse effects of statin.

Topics: Animals; Apoptosis; Cell Line; Endoplasmic Reticulum Stress; Hydroxymethylglutaryl-CoA Reductase Inhibitors; JNK Mitogen-Activated Protein Kinases; Male; MAP Kinase Signaling System; Mice; Mice, Inbred C57BL; Muscle Fibers, Skeletal; Myoblasts, Skeletal; Taurochenodeoxycholic Acid; Transcription Factor CHOP

Localized drug delivery represents one of the most challenging uses of systems based on conductive polymer films. Typically, anionic drugs are incorporated within conductive polymers through electrostatic interaction with the positively charged polymer. Following this approach, the synthetic glucocorticoid dexamethasone phosphate is often delivered from neural probes to reduce the inflammation of the surrounding tissue. In light of the recent literature on the neuroprotective and anti-inflammatory properties of tauroursodeoxycholic acid (TUDCA), for the first time, this natural bile acid was incorporated within poly(3,4-ethylenedioxythiophene) (PEDOT). The new material, PEDOT-TUDCA, efficiently promoted an electrochemically controlled delivery of the drug, while preserving optimal electrochemical properties. Moreover, the low cytotoxicity observed with viability assays, makes PEDOT-TUDCA a good candidate for prolonging the time span of chronic neural recording brain implants.

Topics: Biocompatible Materials; Bridged Bicyclo Compounds, Heterocyclic; Drug Delivery Systems; Electric Conductivity; Electrochemical Techniques; Humans; Polymers; Taurochenodeoxycholic Acid

To determine the effectiveness of a single or a combination of topical neurotrophic factors (NFs) in protecting retinal ganglion cells (RGCs) in the rat optic nerve crush (ONC) model, the left ONC was performed to induce the death of the RGCs in adult Sprague-Dawley rats. The NFs studied were tauroursodeoxycholic acid (TUDCA), citicoline, neurotrophin-4 (NT-4), combined TUDCA/citicoline (Doublet-1), combined TUDCA/NT-4 (Doublet-2), combined TUDCA/citicoline/NT-4 (Triplet), and PBS. After 2 weeks, the number of RGCs was determined by Brn3a immunostaining. The optic nerves were immunostained for anti-Growth Associated Protein-43(GAP-43) and -200kD neurofilament heavy antibody to study optic nerve regeneration. Two weeks after the ONC, the densities of RGCs in all treated eyes were significantly higher than that of the PBS treated eyes. In the Triplet group, the number of RGC axons after ONC was significantly higher than that in all of the single treatment groups and the number of TUNEL positive cells was significantly reduced and the number of GAP-43 immunopositive axons was significantly greater than those in the PBS group. Neovascularization was observed only in the Doublet-1 group. We conclude that the combination of the three NFs was the most effective way to protect RGCs after the ONC.

Topics: Administration, Topical; Animals; Cell Count; Cytidine Diphosphate Choline; Disease Models, Animal; Drug Therapy, Combination; Histocytochemistry; Immunohistochemistry; Nerve Growth Factors; Neuroprotective Agents; Optic Nerve Injuries; Rats, Sprague-Dawley; Retinal Ganglion Cells; Taurochenodeoxycholic Acid; Treatment Outcome

The role of endoplasmic reticulum (ER) stress in cardiovascular disease is now recognized. Tauroursodeoxycholic acid (TUDCA) is known to have cardiovascular protective effects by decreasing ER stress. This study aimed to assess the ability of TUDCA to decrease ER stress, inhibit dedifferentiation of vascular smooth muscle cells (VSMCs), and reduce in-stent restenosis.. The effect of TUDCA on dedifferentiation of VSMCs and ER stress was investigated in vitro using wound-healing assays, MTT assays, and western blotting. For in vivo studies, 18 rabbits were fed an atherogenic diet to induce atheroma formation. Bare metal stents (BMS), BMS+TUDCA or Firebird stents were implanted in the left common carotid artery. Rabbits were euthanized after 28 days and processed for scanning electron microscope (SEM), histological examination (HE), and immunohistochemistry.. In vitro TUDCA (10-1000 μmol/L) treatment significantly inhibited platelet-derived growth factor (PDGF)-BB-induced proliferation and migration in VSMCs in a concentration-dependent manner and decreased ER stress markers (IRE1, XBP1, KLF4, and GRP78). In vivo, we confirmed no significant difference in neointimal coverage on three stents surfaces; neointimal was significantly lower with BMS+TUDCA (1.6 ± 0.2 mm. TUDCA inhibited dedifferentiation of VSMCs by decreasing ER stress and reduced in-stent restenosis, possibly through downregulation of the IRE1/XBP1 signaling pathway.

Topics: Administration, Oral; Animals; Aorta, Thoracic; Carotid Arteries; Carotid Artery Diseases; Cell Dedifferentiation; Cell Movement; Cell Proliferation; Cells, Cultured; Disease Models, Animal; Drug-Eluting Stents; Endoplasmic Reticulum Stress; Endovascular Procedures; Kruppel-Like Factor 4; Male; Membrane Proteins; Muscle, Smooth, Vascular; Myocytes, Smooth Muscle; Neointima; Protein Serine-Threonine Kinases; Rabbits; Rats, Sprague-Dawley; Recurrence; Signal Transduction; Taurochenodeoxycholic Acid; X-Box Binding Protein 1

This study was conducted to investigate the regulation of endoplasmic reticulum stress on Nrf2 signaling pathway in the kidneys of rats.. Rats were divided into twelve groups of six animals each. Some groups were pre-administered with bacitracin or tauroursodeoxycholic acid (TUDCA), and all of them were treated with 5-20 μmol/kg cadmium (Cd) for 48 h. The oxidative stress levels were analyzed using kits. The mRNA and protein expression levels of endoplasmic reticulum stress-related factors and Nrf2 signaling pathway-related factors were determined using RT-PCR and western blot.. Cd exposure resulted in oxidative stress in the kidneys of rats and upregulated the expression of endoplasmic reticulum stress (ERS)-related factors and Nrf2 signaling pathway-related factors, especially at doses of 10 and 20 μmol/kg Cd, and the expression changes were particularly obvious. Moreover, after pretreatment with bacitracin, Cd upregulated the expression of ERS-related factors to a certain extent and, at higher doses, increased the mRNA expression of Nrf2. After pretreatment with TUDCA, Cd reduced the level of ERS to a certain extent; however, at these doses, there were no significant changes in the expression of Nrf2.. Cadmium can result in ERS and oxidative stress in the kidneys of rats, activate Nrf2, and upregulate the transcriptional expression of phase II detoxification enzymes under these experimental conditions. ERS has a positive regulation effect on Nrf2 signaling pathway but has little effect on the negative regulation of Nrf2 signaling pathway in cadmium toxicity.

Topics: Animals; Cadmium; Endoplasmic Reticulum Stress; Environmental Pollutants; Female; Kidney; Male; NF-E2-Related Factor 2; Oxidative Stress; Rats, Sprague-Dawley; Signal Transduction; Taurochenodeoxycholic Acid

Chronic kidney disease (CKD) leads to the loss of kidney function, as well as the dysfunction of several other organs due to the release of uremic toxins into the system. In a murine CKD model, reactive oxygen species (ROS) generation and endoplasmic reticulum (ER) stress are increased in the hippocampus. Mesenchymal stem cells (MSCs) are one of the candidates for cell-based therapy for CKD; however severe pathophysiological conditions can decrease their therapeutic potential. To address these issues, we established tauroursodeoxycholic acid (TUDCA)-treated MSCs using MSCs isolated from patients with CKD (CKD-hMSCs) and assessed the survival and ROS generation of neural cell line SH-SY5Y cells by co-culturing with TUDCA-treated CKD-hMSCs. In the presence of the uremic toxin

Topics: Adenine; Animals; Cell Line; Cell Survival; Coculture Techniques; Cresols; Disease Models, Animal; Endoplasmic Reticulum Stress; Hippocampus; Humans; Mesenchymal Stem Cell Transplantation; Mesenchymal Stem Cells; Mice; PrPC Proteins; Reactive Oxygen Species; Renal Insufficiency, Chronic; Signal Transduction; Taurochenodeoxycholic Acid; Up-Regulation

Bear bile powder is a valuable medicinal material characterized by high content of tauroursodeoxycholic acid (TUDCA) at a certain ratio to taurochenodeoxycholic acid (TCDCA). We had created an engineered E. coli harboring two-step bidirectional oxidative and reductive enzyme-catalyzing pathway that could rapidly convert TCDCA to TUDCA at a specific percentage in shake flasks.. We reported here the large-scale production of TUDCA containing products by balancing the bidirectional reactions through optimizing fermentation process of the engineered E. coli in fermenters. The fermentation medium was firstly optimized based on M9 medium using response surface methodology, leading to a glycerol and yeast extract modified M9-GY medium benefits for both cell growth and product conversion efficiency. Then isopropylthio-β-galactoside induction and fed-stock stage was successively optimized. Finally, a special deep-tank static process was developed to promote the conversion from TCDCA to TUDCA. Applying the optimal condition, fermentation was performed by separately supplementing 30 g refined chicken bile powder and 35 g crude chicken bile powder as substrates, resulting in 29.35 ± 2.83 g and 30.78 ± 3.04 g powder products containing 35.85 ± 3.85% and 27.14 ± 4.23% of TUDCA at a ratio of 1.49 ± 0.14 and 1.55 ± 0.19 to TCDCA, respectively, after purification and evaporation of the fermentation broth. The recovery yield was 92.84 ± 4.21% and 91.83 ± 2.56%, respectively.. This study provided a practical and environment friendly industrialized process for producing artificial substitute of bear bile powder from cheap and readily available chicken bile powder using engineered E. coli microbial cell factory. It also put forward an interesting deep-tank static process to promote the enzyme-catalyzing reactions toward target compounds in synthetic biology-based fermentation.

Topics: Bioreactors; Biotransformation; Escherichia coli; Fermentation; Glycerol; Industrial Microbiology; Taurochenodeoxycholic Acid

Parkinson's disease (PD) is a progressive neurological disorder, mainly characterized by the progressive loss of dopaminergic neurons in the Substantia nigra pars compacta (SNpc) and by the presence of intracellular inclusions, known as Lewy bodies. Despite SNpc being considered the primary affected region in PD, the neuropathological features are confined solely to the nigro-striatal axis. With disease progression other brain regions are also affected, namely the cerebral cortex, although the spreading of the neurologic damage to this region is still not completely unraveled. Tauroursodeoxycholic acid (TUDCA) is an endogenous bile acid that has been shown to have antioxidant properties and to exhibit a neuroprotective effect in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) mice model of PD. Moreover, TUDCA anti-inflammatory properties have been reported in glial cells, making it a prominent therapeutic agent in PD. Here, we used C57BL/6 mice injected with MPTP in a sub-acute paradigm aiming to investigate if the neurotoxic effects of MPTP could be extended to the cerebral cortex. In parallel, we evaluated the anti-oxidant, neuroprotective and anti-inflammatory effects of TUDCA. The anti-inflammatory mechanisms elicited by TUDCA were further dissected in microglia cells. Our results show that MPTP leads to a decrease of ATP and activated AMP-activated protein kinase levels in mice cortex, and to a transient increase in the expression of antioxidant downstream targets of nuclear factor erythroid 2 related factor 2 (Nrf-2), and parkin. Notably, MPTP increases pro-inflammatory markers, while down-regulating the expression of the anti-inflammatory protein Annexin-A1 (ANXA1). Importantly, we show that TUDCA treatment prevents the deleterious effects of MPTP, sustains increased levels of antioxidant enzymes and parkin, and most of all negatively modulates neuroinflammation and up-regulates ANXA1 expression. Additionally, results from cellular models using microglia corroborate TUDCA modulation of ANXA1 synthesis, linking inhibition of neuroinflammation and neuroprotection by TUDCA.

Topics: Adenosine Triphosphate; AMP-Activated Protein Kinase Kinases; Animals; Annexin A1; Anti-Inflammatory Agents; Cell Line; Cerebral Cortex; Male; Mice; Mice, Inbred C57BL; Microglia; MPTP Poisoning; Neuroprotective Agents; NF-E2-Related Factor 2; Protein Kinases; Taurochenodeoxycholic Acid; Ubiquitin-Protein Ligases

Although autologous human mesenchymal stem cells (hMSCs) are a promising source for regenerative stem cell therapy in chronic kidney disease (CKD), the barriers associated with pathophysiological conditions limit therapeutic applicability to patients. We confirmed that level of cellular prion protein (PrP

Topics: Animals; Biomarkers; Cell Proliferation; Cytokines; Disease Models, Animal; Humans; Inflammation Mediators; Ischemia; Membrane Potential, Mitochondrial; Mesenchymal Stem Cell Transplantation; Mesenchymal Stem Cells; Mice; Mitochondria; Mitophagy; PrPC Proteins; Renal Insufficiency, Chronic; Taurochenodeoxycholic Acid

7α-Hydroxysteroid dehydrogenase (7α-HSDH) is an NAD(P)H-dependent oxidoreductase belonging to the short-chain dehydrogenases/reductases. In vitro, 7α-HSDH is involved in the efficient biotransformation of taurochenodeoxycholic acid (TCDCA) to tauroursodeoxycholic acid (TUDCA). In this study, a gene encoding novel 7α-HSDH (named as St-2-1) from fecal samples of black bear was cloned and heterologously expressed in Escherichia coli. The protein has subunits of 28.3 kDa and a native size of 56.6 kDa, which suggested a homodimer. We studied the relevant properties of the enzyme, including the optimum pH, optimum temperature, thermal stability, activators, and inhibitors. Interestingly, the data showed that St-2-1 differs from the 7α-HSDHs reported in the literature, as it functions under acidic conditions. The enzyme displayed its optimal activity at pH 5.5 (TCDCA). The acidophilic nature of 7α-HSDH expands its application environment and the natural enzyme bank of HSDHs, providing a promising candidate enzyme for the biosynthesis of TUDCA or other related chemical entities.

Topics: Animals; Cloning, Molecular; Enzyme Stability; Evolution, Molecular; Feces; Gastrointestinal Microbiome; Hydrogen-Ion Concentration; Hydroxysteroid Dehydrogenases; Molecular Weight; Protein Multimerization; Taurochenodeoxycholic Acid; Thermodynamics; Ursidae

Hutchinson-Gilford progeria syndrome (HGPS) is a rare genetic disorder caused by progerin, a mutant lamin A variant. HGPS patients display accelerated aging and die prematurely, typically from atherosclerosis complications. Recently, we demonstrated that progerin-driven vascular smooth muscle cell (VSMC) loss accelerates atherosclerosis leading to premature death in apolipoprotein E-deficient mice. However, the molecular mechanism underlying this process remains unknown. Using a transcriptomic approach, we identify here endoplasmic reticulum stress (ER) and the unfolded protein responses as drivers of VSMC death in two mouse models of HGPS exhibiting ubiquitous and VSMC-specific progerin expression. This stress pathway was also activated in HGPS patient-derived cells. Targeting ER stress response with a chemical chaperone delayed medial VSMC loss and inhibited atherosclerosis in both progeria models, and extended lifespan in the VSMC-specific model. Our results identify a mechanism underlying cardiovascular disease in HGPS that could be targeted in patients. Moreover, these findings may help to understand other vascular diseases associated with VSMC death, and provide insight into aging-dependent vascular damage related to accumulation of unprocessed toxic forms of lamin A.

Topics: Animals; Aorta; Apoptosis; Atherosclerosis; Disease Models, Animal; Endoplasmic Reticulum Stress; Gene Expression; HSP90 Heat-Shock Proteins; Kaplan-Meier Estimate; Lamin Type A; Longevity; Male; Mice; Mice, Inbred C57BL; Mice, Transgenic; Muscle, Smooth, Vascular; Progeria; Protein Disulfide-Isomerases; Taurochenodeoxycholic Acid; Unfolded Protein Response

Mutations in the retinitis pigmentosa GTPase regulator (RPGR) gene are the predominant cause of retinitis pigmentosa. RPGR plays a critical role as a scaffold protein in the regulation of protein trafficking from the basal body to the axoneme, where the cargoes are transported to the outer segments (OSs) of photoreceptors. This trafficking process is controlled directly by intraflagellar transport complexes and regulated by the RPGR protein complex, although the precise mechanisms have yet to be defined. We used an Rpgr conditional knockout (cko) mouse model to investigate the disease mechanisms during retinal degeneration and to evaluate the protective effects of tauroursodeoxycholic acid (TUDCA). Rhodopsin, cone opsins and transducin were mislocalized in Rpgr cko photoreceptors, while localization of NPHP4 to connecting cilia was absent, suggesting that RPGR is required for ciliary protein trafficking. Microglia were activated in advance of retinal degeneration in Rpgr cko mouse retinas. TUDCA treatment suppressed microglial activation and inflammation and prevented photoreceptor degeneration in Rpgr cko mice. Our data demonstrated that TUDCA has therapeutic potential for RPGR-associated RP patients.

Topics: Animals; Apoptosis; Cilia; Disease Models, Animal; DNA-Binding Proteins; Eye Proteins; Mice, Knockout; Microglia; Neuroprotection; Photoreceptor Cells, Vertebrate; Retina; Retinal Degeneration; Taurochenodeoxycholic Acid

Accumulating evidence has shown that tauroursodeoxycholic acid (TUDCA) is neuroprotective in different animal models of neurological diseases. However, whether TGR5 agonist TUDCA can improve lipopolysaccharide (LPS)-induced cognitive impairment in mice is less clear. Using a model of cognitive impairment with LPS (2.0 μg) we investigated the effects of TUDCA (200 or 400 μg) on cognitive dysfunction and neurotoxicity in mice. Both Morris water maze and Y-maze avoidance tests showed that TUDCA treatment significantly alleviated LPS-induced behavioral impairments. More importantly, we found that TUDCA treatment reversed TGR5 down-regulation, prevented neuroinflammation via inhibiting NF-κB signaling in the hippocampus of LPS-treated mice. Additionally, TUDCA treatment decreased LPS-induced apoptosis through decreasing TUNEL-positive cells and the overexpression of caspase-3, increasing the ratio of Bcl-2/Bax. TUDCA treatment also ameliorated synaptic plasticity impairments by increasing the ratio of mBDNF/proBDNF, the number of dendritic spines and the expression of synapse-associated proteins in the hippocampus. Our results indicated that TUDCA can improve cognitive impairment and neurotoxicity induced by LPS in mice, which is involved in TGR5-mediated NF-κB signaling.

Topics: Animals; Apoptosis; Cognitive Dysfunction; Hippocampus; Lipopolysaccharides; Mice; Microglia; Neurons; Neuroprotective Agents; NF-kappa B; Receptors, G-Protein-Coupled; Synapses; Taurochenodeoxycholic Acid

Chronic exposure to cyclosporine causes nephrotoxicity and organ damage. Here we show that cyclosporine nephrotoxicity in vivo is associated with the activation of the unfolded protein response (UPR) pathway to initiate tissue fibrosis. We demonstrate that cyclosporine therapy activated the IRE1α branch of the unfolded protein response (UPR) and stimulated the TGFβ1 signaling pathway in the kidneys of male mice. Co-administration of the proteostasis promoter tauroursodeoxycholic acid (TUDCA) with cyclosporine inhibited the UPR pathway in the kidneys of treated male mice as well as decreased the development of renal fibrogenesis.

Topics: Animals; Cyclosporine; Disease Models, Animal; Fibrosis; Kidney; Kidney Diseases; Male; Mice; Taurochenodeoxycholic Acid; Unfolded Protein Response

Conjugated bile acids (CBAs), such as tauroursodeoxycholic acid (TUDCA), are known to resolve the inflammatory and unfolded protein response (UPR) in inflammatory diseases, such as asthma. Whether CBAs exert their beneficial effects on allergic airway responses via 1 arm or several arms of the UPR, or alternatively through the signaling pathways for conserved bile acid receptor, remains largely unknown. We used a house dust mite-induced (HDM-induced) murine model of asthma to evaluate and compare the effects of 5 CBAs and 1 unconjugated bile acid in attenuating allergen-induced UPR and airway responses. Expression of UPR-associated transcripts was assessed in airway brushings from human patients with asthma and healthy subjects. Here we show that CBAs, such as alanyl β-muricholic acid (AβM) and TUDCA, significantly decreased inflammatory, immune, and cytokine responses; mucus metaplasia; and airway hyperresponsiveness, as compared with other CBAs in a model of allergic airway disease. CBAs predominantly bind to activating transcription factor 6α (ATF6α) compared with the other canonical transducers of the UPR, subsequently decreasing allergen-induced UPR activation and resolving allergic airway disease, without significant activation of the bile acid receptors. TUDCA and AβM also attenuated other HDM-induced ER stress markers in the lungs of allergic mice. Quantitative mRNA analysis of airway epithelial brushings from human subjects demonstrated that several ATF6α-related transcripts were significantly upregulated in patients with asthma compared with healthy subjects. Collectively, these results demonstrate that CBA-based therapy potently inhibits the allergen-induced UPR and allergic airway disease in mice via preferential binding of the canonical transducer of the UPR, ATF6α. These results potentially suggest a novel avenue to treat allergic asthma using select CBAs.

Topics: Allergens; Animals; Asthma; Bile Acids and Salts; Chemokines; Cytokines; Female; Humans; Hypersensitivity; Inflammation; Lung; Metaplasia; Mice; Mice, Inbred BALB C; Mice, Inbred C57BL; Proteostasis Deficiencies; Pyroglyphidae; Receptors, G-Protein-Coupled; Respiratory Hypersensitivity; Taurochenodeoxycholic Acid; Unfolded Protein Response

Exposures to ionizing radiation can cause depletion in stem cell reservoirs and lead to chronic injury processes that exacerbate carcinogenic and inflammatory responses. Therefore, radioprotective measures, against both acute and chronic biological effects of radiation, require frequent intake of nontoxic natural products, which have practical oral administration. The goal of this study was to characterize the radioprotective, radiomitigative and radiation-induced bystander effect-inhibiting properties of endogenous metabolites: phenylacetate, ursodeoxycholate and tauroursodeoxycholate. Compounds were administered pre- and postirradiation as well as in donor and recipient bystander flasks to analyze whether these might adequately protect against radiation injury as well as facilitate recovery from the exposures. The clonogenic HCT116 p53 wild-type cancer cell line in this study shares characteristics of stem cells, such as high reproductive viability, which is an effective marker to demonstrate compound effectiveness. Clonogenic assays were therefore used to characterize radioprotective, radiomitigative and bystander inhibiting properties of treatment compounds whereby cellular responses to radiation were quantified with macroscopic colony counts to measure cell survival in flasks. The results were statistically significant for phenylacetate and tauroursodeoxycholate when administered preirradiation, conferring radioprotection up to 2 Gy, whereas administration postirradiation and in bystander experiments did not confer radioprotection

Topics: Acetates; Bystander Effect; Cell Survival; Colonic Neoplasms; Dose-Response Relationship, Radiation; HCT116 Cells; Humans; Phenols; Radiation-Protective Agents; Signal Transduction; Taurochenodeoxycholic Acid; Ursodeoxycholic Acid

Wheat production is largely restricted by adverse environmental stresses. Under many undesirable conditions, endoplasmic reticulum (ER) stress can be induced. However, the physiological and molecular responses of wheat to ER stress remain poorly understood. We used dithiothreitol (DTT) and tauroursodeoxycholic acid (TUDCA) to induce or suppress ER stress in wheat cells, respectively, with the aim to reveal the molecular background of ER stress responses using a combined approach of transcriptional profiling and morpho-physiological characterization.. To understand the mechanism of wheat response to ER stress, three wheat cultivars were used in our pre-experiments. Among them, the cultivar with a moderate stress tolerance, Yunong211 was used in the following experiments. We used DTT (7.5 mM) to induce ER stress and TUDCA (25 μg·mL. Morpho-physiological results showed DTT significantly reduced plant height and biomass, decreased contents of chlorophyll and water, increased electrolyte leakage rate and antioxidant enzymes activity, and accelerated the cell death ratio, whereas these changes were all remarkably alleviated after TUDCA co-treatment. Therefore, RNA sequencing was performed to determine the genes involved in regulating wheat response to stress. Transcriptomic analysis revealed that 8204 genes were differentially expressed in three treatment groups. Among these genes, 158 photosynthesis-related genes, 42 antioxidant enzyme genes, 318 plant hormone-related genes and 457 transcription factors (TFs) may play vital roles in regulating wheat response to ER stress. Based on the comprehensive analysis, we propose a hypothetical model to elucidate possible mechanisms of how plants adapt to environmental stresses.. We identified several important genes that may play vital roles in wheat responding to ER stress. This work should lay the foundations of future studies in plant response to environmental stresses.

Topics: Dithiothreitol; Endoplasmic Reticulum Stress; Gene Expression Profiling; Gene Expression Regulation, Plant; Gene Ontology; Genes, Plant; Plant Leaves; Plant Roots; Reproducibility of Results; Sequence Analysis, RNA; Taurochenodeoxycholic Acid; Transcription Factors; Transcriptome; Triticum

Cholesterol and lipid metabolism are associated with osteoarthritis (OA) in human cartilage. High cholesterol levels in OA chondrocytes leads to decreased membrane fluidity and blocks the signaling cascade associated with the expression of chondrogenic genes. It is known that bile acid plays a role in regulating cholesterol homeostasis and the digestion of fats in the human body. Tauroursodeoxycholic acid (TUDCA), as a member of the bile acid family, also aids in the transport of cellular cholesterol. In this study, we hypothesized that TUDCA might be able to promote the restoration of OA cartilage by reducing membrane cholesterol levels in OA chondrocytes and by stimulating the chondrogenic signaling cascade. To assess this hypothesis, we investigated the effects of TUDCA on degenerated chondrocytes isolated from patients with OA. Importantly, treatment with TUDCA at sub-micellar concentrations (2500 μM) significantly increased cell proliferation and Cyclin D1 expression compared with the controls. In addition, the expression of chondrogenic marker genes (SOX9, COL2, and ACAN), proteins (SOX9 and COL2), and glycosaminoglycan (Chondroitin sulfate) was much higher in the TUDCA-treated group compared to the controls. We also found that TUDCA treatment significantly reduced the intracellular cholesterol levels in the chondrocytes and increased membrane fluidity. Furthermore, the stability of TGF receptor 1 and activity of focal adhesion proteins were also increased following TUDCA treatment. Together, these results demonstrated that TUDCA could be used as an alternative treatment for the restoration of OA cartilage.

Topics: Cell Proliferation; Cell Survival; Cholesterol; Chondrocytes; Chondrogenesis; Dose-Response Relationship, Drug; Focal Adhesions; Humans; Intracellular Space; Membrane Fluidity; Osteoarthritis; Receptors, Transforming Growth Factor beta; Signal Transduction; Taurochenodeoxycholic Acid

Tauroursodeoxycholate (TUDC) is well known to protect against glycochenodeoxycholate (GCDC)-induced apoptosis in rat hepatocytes. In the present study, we analyzed whether TUDC also exerts protective effects by modulating GCDC-induced gene expression changes. For this, gene array-based transcriptome analysis and quantitative polymerase chain reaction (qPCR) were performed on RNA isolated from rat livers perfused with GCDC, TUDC or a combination of both (each 20 μm for 2 h). GCDC led to a significant increase of lactate dehydrogenase (LDH) into the effluent perfusate, which was prevented by TUDC. GCDC, TUDC and co-perfusion induced distinct gene expression changes. While GCDC upregulated the expression of several pro-inflammatory genes, co-perfusion with TUDC increased the expression of pro-proliferative and anti-apoptotic p53 target genes. In line with this, levels of serine20-phosphorylated p53 and of its target gene p21 were elevated by GCDC in a TUDC-sensitive way. GCDC upregulated the oxidative stress surrogate marker 8OH(d)G and the pro-apoptotic microRNAs miR-15b/16 and these effects were prevented by TUDC. The upregulation of miR-15b and miR-16 in GCDC-perfused livers was accompanied by a downregulation of several potential miR-15b and miR-16 target genes. The present study identified changes in the transcriptome of the rat liver which suggest, that TUDC is hepatoprotective by counteracting GCDC-induced gene expression changes.

Topics: Animals; Apoptosis; Cell Proliferation; Gene Expression; Glycochenodeoxycholic Acid; Liver; Male; Oligonucleotide Array Sequence Analysis; Rats; Rats, Wistar; Real-Time Polymerase Chain Reaction; RNA; Taurochenodeoxycholic Acid

Disruption of endoplasmic reticulum (ER) homeostasis, often termed ER stress, is intrinsically linked with perturbation of lipid metabolism in humans and mice. Whether ER homeostasis is affected in cows experiencing fatty liver is unknown. The aim of this study was to investigate the potential role of ER stress in hepatic lipid accumulation in calf hepatocytes and ER stress status in dairy cows with severe fatty liver. In vitro experiments were conducted in which hepatocytes were isolated from calves and treated with different concentrations of fatty acids, tauroursodeoxycholic acid (TUDCA; a canonical inhibitor of ER stress), or both. The increase in phosphorylation level of protein kinase RNA-like ER kinase (PERK) and inositol requiring protein-1α (IRE1α) proteins, and the cleavage of activating transcription factor-6 (ATF6) protein in response to increasing doses of fatty acids (which were reversed by TUDCA treatment) in primary hepatocytes underscored a mechanistic link between fatty acids and ER stress. In addition, fatty acid treatment increased the abundance of sterol regulatory element-binding protein 1c, acetyl-CoA carboxylase-α, fatty acid synthase, and diacylglycerol acyltransferase 1, and lipid accumulation in calf primary hepatocytes, whereas inhibition of ER stress by incubating with TUDCA significantly weakened these effects. Overall, results in vitro indicate that inhibition of ER stress in calf hepatocytes alleviates fatty acid-induced lipid accumulation by downregulating the expression of lipogenic genes. In vivo experiments, liver and blood samples were collected from cows diagnosed as healthy (n = 15) or with severe fatty liver (n = 15). The phosphorylation level of PERK and IRE1α, the cleavage of ATF6 protein, and the abundance of several unfolded protein response genes (78 kDa glucose-regulated protein, AMP-dependent transcription factor 4, and spliced X-box binding protein 1) were greater in liver of cows with severe fatty liver. The present in vivo study confirms the occurrence of ER stress in dairy cows with severe fatty liver. Considering the causative role of fatty acid-induced ER stress in hepatic lipid accumulation in calf hepatocytes, the existence of ER stress in the liver of severe fatty liver cows may presage its participation in fatty liver progression in dairy cows. However, the mechanistic relationship between ER stress and fatty liver in dairy cows remain to be determined.

Topics: Activating Transcription Factor 6; Animals; Cattle; Cattle Diseases; Cells, Cultured; eIF-2 Kinase; Endoplasmic Reticulum Stress; Endoribonucleases; Fatty Acids; Fatty Liver; Female; Hepatocytes; Lipid Metabolism; Lipogenesis; Liver; Mice; Phosphorylation; Taurochenodeoxycholic Acid; Unfolded Protein Response

Neonatal necrotizing enterocolitis (NEC) is a life-threatening disease with severe inflammation and intestinal cell apoptosis. Tauroursodeoxycholic acid (TUDCA) is a recognized endoplasmic reticulum stress (ERS) inhibitor which can inhibit cell apoptosis. Recently, intestinal cell apoptosis has been demonstrated to be vital for the pathogenesis of NEC. The purpose of the present study was to investigate the potential of TUDCA in the treatment of NEC and the possible mechanisms in vivo and in vitro. Our results showed that TUDCA reduced mortality rates, prolonged survival times, significantly diminished intestinal damage, and inhibited intestinal inflammation in the mouse model of NEC. The protective effect of TUDCA on the NEC mouse model was realized through inhibiting the expression levels of ERS markers and inhibiting the apoptosis of intestinal cells. In addition, TUDCA increased the expression of phospho-Akt (p-Akt). Furthermore, we confirmed that TUDCA inhibited the apoptosis of intestinal cells by modulating the PERK-eIF2α ERS pathway and the Akt pathway in vitro studies. Besides, TUDCA effects were impaired by AKT specific inhibitor MK2206 in vitro studies. Therefore, these results indicated that TUDCA alleviated intestinal injury in a mouse model of NEC and inhibited ERS-mediated intestinal cell apoptosis by activating the Akt pathway.

Topics: Animals; Apoptosis; Cell Line; Cytokines; Endoplasmic Reticulum Stress; Enterocolitis, Necrotizing; Enterocytes; Female; Intestines; Mice, Inbred C57BL; Protective Agents; Proto-Oncogene Proteins c-akt; Taurochenodeoxycholic Acid

Increased O-GlcNAcylation, a well-known post-translational modification of proteins causally linked to various detrimental cellular functions in pathological conditions including diabetic retinopathy (DR). Previously we have shown that endothelial activation induced by inflammation and hyperglycemia results in the endoplasmic reticulum (ER) stress-mediated intercellular junction alterations accompanied by visual deficits in a tie2-TNF-α transgenic mouse model. In this study, we tested the hypothesis that increased ER stress via O-GlcNAcylation of VE-Cadherin likely contribute to endothelial permeability. We show that ER stress leads to GRP78 translocation to the plasma membrane, increased O-GlcNAcylation of proteins, particularly VE-Cadherin resulting in a defective complex partnering leading to the loss of retinal endothelial barrier integrity and increased transendothelial migration of monocytes. We further show an association of GRP78 with the VE-Cadherin under these conditions. Interestingly, cells exposed to ER stress inhibitor, tauroursodeoxycholic acid partially mitigated all these effects. Our findings suggest an essential role for ER stress and O-GlcNAcylation in altering the endothelial barrier function and reveal a potential therapeutic target in the treatment of DR.

Topics: Antigens, CD; Blood-Retinal Barrier; Cadherins; Capillary Permeability; Cell Membrane; Cell Movement; Cells, Cultured; Endoplasmic Reticulum; Endoplasmic Reticulum Chaperone BiP; Endoplasmic Reticulum Stress; Endothelial Cells; Glycosylation; Heat-Shock Proteins; Humans; Monocytes; Protein Transport; Taurochenodeoxycholic Acid

Inherited retinal degeneration (RD) comprises a heterogeneous group of retinopathies that rank among the main causes of blindness. Tauroursodeoxycholic acid (TUDCA) is taurine conjugate hydrophilic bile acid that demonstrates profound protective effects against a series of neurodegenerative diseases related to oxidative stress. This study sought to evaluate the TUDCA induced effects of on a pharmacologically induced RD animal model by electroretinogram (ERG) examination, behavior tests, morphological analysis and immunochemistry assay. Massive photoreceptor degeneration in mice retina was induced by an intraperitoneal administration of N-methyl-N-nitrosourea(MNU). Subcutaneous delivery of TUDCA inhibits effectively the photoreceptor loss and visual impairments in the MNU administered mice. In the retinal flat-mounts of TUDCA treated mice, the cone photoreceptors were efficiently preserved. Furthermore, the multi-electrodes array (MEA) was used to detect the firing activities of retinal ganglion cells within the inner retinal circuits. TUDCA therapy could restrain the spontaneous firing response, enhance the light induced firing response, and preserve the basic configurations of ON-OFF signal pathway in degenerative retinas. Our MEA assay provided an example to evaluate the potency of pharmacological compounds on retinal plasticity. TUDCA affords these protective effects by modulating apoptosis and alleviating oxidative stress in the degenerative retina. In conclusion, TUDCA therapy can ameliorate the photoreceptor degeneration and rectify the abnormities in visual signal transmission. These findings suggest that TUDCA might act as a potential medication for these retinopathies with progressive photoreceptor degeneration.

Topics: Animals; Apoptosis; Disease Models, Animal; Electroretinography; Female; Male; Methylnitrosourea; Mice; Mice, Inbred C57BL; Oxidative Stress; Photoreceptor Cells, Vertebrate; Retina; Retinal Cone Photoreceptor Cells; Retinal Degeneration; Retinal Ganglion Cells; Taurochenodeoxycholic Acid

Although neurogenesis occurs in restricted regions of the adult mammalian brain, neural stem cells (NSCs) produce very few neurons during ageing or after injury. We have recently discovered that the endogenous bile acid tauroursodeoxycholic acid (TUDCA), a strong inhibitor of mitochondrial apoptosis and a neuroprotective in animal models of neurodegenerative disorders, also enhances NSC proliferation, self-renewal, and neuronal conversion by improving mitochondrial integrity and function of NSCs. In the present study, we explore the effect of TUDCA on regulation of NSC fate in neurogenic niches, the subventricular zone (SVZ) of the lateral ventricles and the hippocampal dentate gyrus (DG), using rat postnatal neurospheres and adult rats exposed to the bile acid. TUDCA significantly induced NSC proliferation, self-renewal, and neural differentiation in the SVZ, without affecting DG-derived NSCs. More importantly, expression levels of mitochondrial biogenesis-related proteins and mitochondrial antioxidant responses were significantly increased by TUDCA in SVZ-derived NSCs. Finally, intracerebroventricular administration of TUDCA in adult rats markedly enhanced both NSC proliferation and early differentiation in SVZ regions, corroborating in vitro data. Collectively, our results highlight a potential novel role for TUDCA in neurologic disorders associated with SVZ niche deterioration and impaired neurogenesis.

Topics: Animals; Cell Proliferation; Lateral Ventricles; Mitochondria; Neural Stem Cells; Neurites; Neurogenesis; Organelle Biogenesis; Rats; Rats, Sprague-Dawley; Reactive Oxygen Species; Taurochenodeoxycholic Acid

The non-union rate after lumbar spinal fusion is potentially as high as 48%. To support efficient bone regeneration, recombinant human bone morphogenetic protein-2 (rhBMP-2) is commonly used as it is regarded as the most potent bone-inducing molecule. However, recently, there have been increasing concerns on the use of rhBMP-2 such as serious complications, including seroma and heterotopic ossification, and the low quality of bone at the center of fusion mass. Thus, many studies were conducted to find and to develop a potential alternative to rhBMP-2. In this study, we investigated the osteogenic potential of tauroursodeoxycholic acid (TUDCA) in the mouse fusion model and compared its effects with rhBMP-2. Twenty-four mice underwent bilateral posterolateral lumbar spinal fusion bone formation at L4-L5. Collagen sponge infused with saline, TUDCA, or rhBMP-2 was implanted at the fusion area. Two and 4 weeks postimplantation, bone formation and tissue regeneration were evaluated via micro-computed tomography and histological analysis. Compared with the TUDCA-treated group, the rhBMP-2 treatment produced a higher amount of bone fusion formation after 2 weeks but also showed higher resorption of the centralized bone after 4 weeks. Interestingly, the TUDCA-treated group developed higher trabecular thickness compared with rhBMP-2 after 4 weeks. Moreover, TUDCA treatment showed distinct angiogenic activity in human umbilical vein endothelial cells as confirmed by an in vitro tube formation assay. Our findings suggest that TUDCA is comparable to rhBMP-2 in supporting bone regeneration and spinal bone formation fusion by increasing trabecular thickness and promoting angiogenesis. Finally, our results indicate that TUDCA can be utilized as a potential alternative to rhBMP-2.

Topics: Animals; Bone Morphogenetic Protein 2; Female; Humans; Mice; Mice, Inbred ICR; Models, Biological; Osteogenesis; Recombinant Proteins; Spinal Fusion; Taurochenodeoxycholic Acid

The aim of this study was to evaluate hepatic polyunsaturated fatty acids (PUFAs) and inflammatory response in an animal and cell model of endoplasmic reticulum (ER) stress. Rats were divided into control, tunicamycin (TM)-treated, and TM + tauroursodeoxycholic acid (TUDCA)-treated groups. Hepatic ER stress was induced by TM and the ER stress inhibitor TUDCA was injected 30 min before induction of ER stress. Liver THLE-3 cells were treated with TM and TUDCA was administered in advance to decrease cytotoxic effects. Necroinflammation was evaluated in liver sections, while cell viability was determined using a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay kit. ER stress was confirmed by immunofluorescence and Western blot analysis of C/EBP-homologous protein and 78-kDa glucose-regulated protein. Arachidonic acid (C20:4n-6), dihomo-γ-linolenic acid (C20:3n-6), eicosapentaenoic acid (C20:5n-3), and docosahexaenoic acid (C22:6n-3) in liver tissue and THLE-3 cells were determined by liquid chromatography tandem mass spectrometry (LC-MS/MS). Phospholipase A2 (PLA2), cyclooxygenase (COX), and prostaglandin E2 (PGE2) were measured in tissue and cell samples. Hepatic ER stress was accomplished by TM and was alleviated by TUDCA. TM treatment significantly decreased PUFAs in both liver and THLE-3 cells compared to controls. PLA2, COX, and PGE2 levels were significantly increased in TM-treated rats and THLE-3 cells compared to controls. TUDCA leads to a partial restoration of liver PUFA levels and decreased PLA2, COX, and PGE2. This study reports decreased PUFA levels in ER stress and supports the use of omega-3 fatty acids in liver diseases demonstrating ER stress.

Topics: Animals; Cell Line; Cell Survival; Chemical and Drug Induced Liver Injury; Dinoprostone; Disease Models, Animal; Endoplasmic Reticulum Chaperone BiP; Endoplasmic Reticulum Stress; Fatty Acids, Omega-3; Heat-Shock Proteins; Hepatocytes; Humans; Inflammation; Liver; Male; Phospholipases A2; Prostaglandin-Endoperoxide Synthases; Rats, Wistar; Taurochenodeoxycholic Acid; Transcription Factor CHOP; Tunicamycin

The gut-liver axis is associated with the progression of non-alcoholic fatty liver disease (NAFLD). Targeting the gut-liver axis and bile acid-based pharmaceuticals are potential therapies for NAFLD. The effect of tauroursodeoxycholic acid (TUDCA), a candidate drug for NAFLD, on intestinal barrier function, intestinal inflammation, gut lipid transport and microbiota composition was analysed in a murine model of NAFLD.. The NAFLD mouse model was established by feeding mice a high-fat diet (HFD) for 16 weeks. TUDCA was administered p.o. during the last 4 weeks. The expression levels of intestinal tight junction genes, lipid metabolic and inflammatory genes were determined by quantitative PCR. Tissue inflammation was evaluated by haematoxylin and eosin staining. The gut microbiota was analysed by 16S rRNA gene sequencing.. TUDCA administration attenuated HFD-induced hepatic steatosis, inflammatory responses, obesity and insulin resistance in mice. Moreover, TUDCA attenuated gut inflammatory responses as manifested by decreased intestinal histopathology scores and inflammatory cytokine levels. In addition, TUDCA improved intestinal barrier function by increasing levels of tight junction molecules and the solid chemical barrier. The components involved in ileum lipid transport were also reduced by TUDCA administration in HFD-fed mice. Finally, the TUDCA-treated mice showed a different gut microbiota composition compared with that in HFD-fed mice but similar to that in normal chow diet-fed mice.. TUDCA attenuates the progression of HFD-induced NAFLD in mice by ameliorating gut inflammation, improving intestinal barrier function, decreasing intestinal fat transport and modulating intestinal microbiota composition.

Topics: Animals; Caco-2 Cells; Diet, High-Fat; Gastrointestinal Microbiome; Humans; Intestine, Small; Male; Mice; Mice, Inbred C57BL; Non-alcoholic Fatty Liver Disease; Random Allocation; Taurochenodeoxycholic Acid

Spinal cord injury (SCI) is generally divided into primary and secondary injuries, and apoptosis is an important event of the secondary injury. As an endogenous bile acid and recognized endoplasmic reticulum (ER) stress inhibitor, tauroursodeoxycholic acid (TUDCA) administration has been reported to have a potentially therapeutic effect on neurodegenerative diseases, but its real mechanism is still unclear. In this study, we evaluated whether TUDCA could alleviate traumatic damage of the spinal cord and improve locomotion function in a mouse model of SCI. Traumatic SCI mice were intraperitoneally injected with TUDCA, and the effects were evaluated based on motor function assessment, histopathology, apoptosis detection, qRT-PCR, and western blot at different time periods. TUDCA administration can improve motor function and reduce secondary injury and lesion area after SCI. Furthermore, the apoptotic ratios were significantly reduced; Grp78, Erdj4, and CHOP were attenuated by the treatment. Unexpectedly, the levels of CIBZ, a novel therapeutic target for SCI, were specifically up-regulated. Taken together, it is suggested that TUDCA effectively suppressed ER stress through targeted up-regulation of CIBZ. This study also provides a new strategy for relieving secondary damage by inhibiting apoptosis in the early treatment of spinal cord injury.

Topics: Animals; Apoptosis; Endoplasmic Reticulum Chaperone BiP; Endoplasmic Reticulum Stress; Male; Mice; Models, Biological; Motor Activity; Neurons; Recovery of Function; Repressor Proteins; Spinal Cord Injuries; Taurochenodeoxycholic Acid; Up-Regulation

As a traditional herbal medicine, the fruits of Psoralea corylifolia L. (Fructus Psoraleae (FP)) have been widely used for the treatment of various skin diseases for hundred years. Recently, the emerging FP-induced toxic effects, especially hepatotoxicity, in clinic are getting the public's attention. However, its exact toxic components and mechanisms underlying remain unclear. Bavachin, one of flavonoids in FP, has been documented as a hepatotoxic substance, and the present study aimed to determine the toxicity caused by bavachin and the possible toxic mechanisms involved using human hepatocellular carcinoma (HepG2) cells. Our results showed that bavachin could significantly inhibited cell proliferation and trigger the endoplasmic reticulum (ER) stress in a dose dependent manner. Downregulating ER stress using tauroursodeoxycholic acid (TUDCA) obvious attenuated bavachin-triggerd cell apoptosis. Then, small interfering RNA (siRNA) knock-down of Mitofusion2 (Mfn2) resulted in a remarkable aggravation of ER stress through the inhibition of the phosphorylation of protein kinase B (Akt). Additionally, suppression of reactive oxygen species (ROS) by ROS Scavenger (N-acetyl-l-cystein (NAC)) also reduced bavachin-induced ER stress. Taken together, our study demonstrated that bavachin-induced ER stress caused cell apoptosis by Mfn2-Akt pathway, and that ROS may participate upstream in this mechanism. Here, we not only provide a new understanding of ROS/Mfn2/Akt pathway in bavachin-induced cytotoxicity via the ER stress, but also identify a new specific intervention to prevent FP-induced hepatotoxicity in the future.

Topics: Acetylcysteine; Anti-Bacterial Agents; Apoptosis; Cell Proliferation; Cell Shape; Endoplasmic Reticulum Stress; Flavonoids; Free Radical Scavengers; GTP Phosphohydrolases; Hep G2 Cells; Hepatocytes; Humans; Mitochondria, Liver; Osmolar Concentration; Oxidative Stress; Phosphorylation; Protective Agents; Protein Processing, Post-Translational; Proto-Oncogene Proteins c-akt; Reactive Oxygen Species; RNA Interference; Taurochenodeoxycholic Acid

Vascular calcification increases the risk of cardiovascular disease and death in patients with chronic kidney disease (CKD). Increased activity of mammalian target of rapamycin complex 1 (mTORC1) and endoplasmic reticulum (ER) stress-unfolded protein response (UPR) are independently reported to partake in the pathogenesis of vascular calcification in CKD. However, the association between mTORC1 activity and ER stress-UPR remains unknown. We report here that components of the uremic state [activation of the receptor for advanced glycation end products (RAGE) and hyperphosphatemia] potentiate vascular smooth muscle cell (VSMC) calcification by inducing persistent and exaggerated activity of mTORC1. This gives rise to prolonged and excessive ER stress-UPR as well as attenuated levels of sestrin 1 ( Sesn1) and Sesn3 feeding back to inhibit mTORC1 activity. Activating transcription factor 4 arising from the UPR mediates cell death via expression of CCAAT/enhancer-binding protein (c/EBP) homologous protein (CHOP), impairs the generation of pyrophosphate, a potent inhibitor of mineralization, and potentiates VSMC transdifferentiation to the osteochondrocytic phenotype. Short-term treatment of CKD mice with rapamycin, an inhibitor of mTORC1, or tauroursodeoxycholic acid, a bile acid that restores ER homeostasis, normalized mTORC1 activity, molecular markers of UPR, and calcium content of aortas. Collectively, these data highlight that increased and/or protracted mTORC1 activity arising from the uremic state leads to dysregulated ER stress-UPR and VSMC calcification. Manipulation of the mTORC1-ER stress-UPR pathway opens up new therapeutic strategies for the prevention and treatment of vascular calcification in CKD.

Topics: Activating Transcription Factor 4; Animals; Aorta; Aortic Diseases; Cell Death; Cell Proliferation; Cell Transdifferentiation; Disease Models, Animal; Endoplasmic Reticulum Stress; Extracellular Signal-Regulated MAP Kinases; HEK293 Cells; Humans; Mechanistic Target of Rapamycin Complex 1; Mice, Mutant Strains; Muscle, Smooth, Vascular; Osteogenesis; Phosphorylation; Receptor for Advanced Glycation End Products; S100 Proteins; Signal Transduction; Sirolimus; Taurochenodeoxycholic Acid; Unfolded Protein Response; Uremia; Vascular Calcification

Mesenchymal stem cells (MSCs) could be a promising solution in the treatment of various diseases including chronic kidney disease (CKD). However, endoplasmic reticulum (ER) stress induced by ischemia in the area of application limits the integration and survival of MSCs in patients. In our study, we generated ER stress-induced conditions in MSCs using

Topics: Adipose Tissue; Antioxidants; Apoptosis; Cells, Cultured; Cresols; Endoplasmic Reticulum Chaperone BiP; Endoplasmic Reticulum Stress; Humans; Mesenchymal Stem Cells; Oxidative Stress; PrPC Proteins; Reactive Oxygen Species; Taurochenodeoxycholic Acid

This study aimed to investigate the anti-inflammatory effects of tauroursodeoxycholic acid (TUDCA) after spinal cord injury (SCI) in rats. We induced an inflammatory process in RAW 264.7 macrophages, BV2 microglial cells, and bone marrow-derived macrophages (BMM) using lipopolysaccharide (LPS). The anti-inflammatory effects of TUDCA on LPS-stimulated RAW 264.7 macrophages, BV2 microglial cells, and BMMs were analyzed using nitric oxide (NO) assays, quantitative real-time polymerase chain reactions (qRT-PCR), and enzyme-linked immunosorbent assays (ELISA). The pathological changes in lesions of the spinal cord tissue were evaluated by hematoxylin & eosin (H&E) staining, luxol fast blue/cresyl violet-staining and immunofluorescent staining. TUDCA decreased the LPS-stimulated inflammatory mediator, NO. It also suppressed pro-inflammatory cytokines of tumor necrosis factor-α (TNF-α), interleukin 1-β (IL-1β), cyclooxygenase-2 (COX-2), and inducible nitric oxide synthase (iNOS) in both mRNA and protein levels. In addition, TUDCA decreased prostaglandin E

Topics: Animals; Anti-Inflammatory Agents; Bone Marrow Cells; Cytokines; Gene Expression Regulation; Macrophages; Mice; Microglia; Rats, Sprague-Dawley; RAW 264.7 Cells; RNA, Messenger; Spinal Cord Injuries; Taurochenodeoxycholic Acid

The heterotrimeric G-protein binding site on G-protein coupled receptors remains relatively unexplored regarding its potential as a new target of therapeutic intervention or as a secondary site of action by the existing drugs. Tauroursodeoxycholic acid bears structural resemblance to several compounds that were previously identified to specifically bind to the light-activated form of the visual receptor rhodopsin and to inhibit its activation of transducin. We show that TUDCA stabilizes the active form of rhodopsin, metarhodopsin II, and does not display the detergent-like effects of common amphiphilic compounds that share the cholesterol scaffold structure, such as deoxycholic acid. Computer docking of TUDCA to the model of light-activated rhodopsin revealed that it interacts using similar mode of binding to the C-terminal domain of transducin alpha subunit. The ring regions of TUDCA made hydrophobic contacts with loop 3 region of rhodopsin, while the tail of TUDCA is exposed to solvent. The results show that TUDCA interacts specifically with rhodopsin, which may contribute to its wide-ranging effects on retina physiology and as a potential therapeutic compound for retina degenerative diseases.

Topics: Animals; Cattle; Cholagogues and Choleretics; GTP-Binding Proteins; Light; Opsins; Protein Binding; Protein Structure, Secondary; Receptors, G-Protein-Coupled; Rhodopsin; Signal Transduction; Taurochenodeoxycholic Acid

The Endoplasmic Reticulum (ER) is a membranous organelle with diverse structural and functional domains. Peripheral ER includes interconnected tubules, and dense tubular arrays called "ER matrices" together with bona fide flat cisternae. Transitions between these states are regulated by membrane-associated proteins and cytosolic factors. Recently, the small GTPases Rab10 and Rab18 were reported to control ER shape by regulating ER dynamics and fusion. Here, we present evidence that another Rab protein, Rab7a, modulates the ER morphology by controlling the ER homeostasis and ER stress. Indeed, inhibition of Rab7a expression by siRNA or expression of the dominant negative mutant Rab7aT22 N, leads to enlargement of sheet-like ER structures and spreading towards the cell periphery. Notably, such alterations are ascribable neither to a direct modulation of the ER shaping proteins Reticulon-4b and CLIMP63, nor to interactions with Protrudin, a Rab7a-binding protein known to affect the ER organization. Conversely, depletion of Rab7a leads to basal ER stress, in turn causing ER membrane expansion. Both ER enlargement and basal ER stress are reverted in rescue experiments by Rab7a re-expression, as well as by the ER chemical chaperone tauroursodeoxycholic acid (TUDCA). Collectively, these findings reveal a new role of Rab7a in ER homeostasis, and indicate that genetic and pharmacological ER stress manipulation may restore ER morphology in Rab7a silenced cells.

Topics: Endoplasmic Reticulum; Endoplasmic Reticulum Stress; Gene Expression Regulation; HeLa Cells; Homeostasis; Humans; Membrane Proteins; Nogo Proteins; Protein Binding; rab GTP-Binding Proteins; rab7 GTP-Binding Proteins; RNA, Small Interfering; Taurochenodeoxycholic Acid; Vesicular Transport Proteins

To investigate the impact and protective effect of tauroursodeoxycholic acid (TUDCA) on the autophagy of nerve cells in rats with acute spinal cord injury.. Seventy-two 6-8-week-old male Sprague-Dawley (SD) rats were selected and were randomly divided into a sham operation group, a saline control group and a TUDCA treatment group (high and low dose groups). The experimental animals were sacrificed at 24 hours, 5 days and 10 days after spinal cord injury. The Basso, Beattie, Bresnahan locomotor scale was used to assess the hind limb locomotor function after the rats were injured but before sudden death. Electron microscopy, hematoxylin and eosin (HE) staining, TUNEL assays and immunohistochemistry techniques were used to observe the autophagy of the cells. Western blotting was used to analyze the expression of the autophagy-related factor Beclin-1 and the apoptosis-related factor caspase-3, and reverse transcription polymerase chain reaction (RT-PCR) was used to analyze the mRNA expression levels of the above proteins.. The locomotor scores of the rats in the saline group were significantly reduced, their Beclin-1 expression levels in neurons were decreased, and caspase-3 expression was increased. The hind limb locomotor scores of rats in the TUDCA groups were decreased, with no difference between the high- and low-dose groups. Beclin-1 expression in their neurons was increased, and caspase-3 expression was decreased; there was a significant difference when compared with the control group, while there was no significant difference between the high- and low-dose groups.. TUDCA significantly activates the neuronal autophagic expression in rats with acute spinal cord injury to inhibit the apoptosis of nerve cells; therefore, it has a protective effect on neurons.

Topics: Animals; Apoptosis; Autophagy; Locomotion; Male; Neurons; Neuroprotective Agents; Random Allocation; Rats; Rats, Sprague-Dawley; Spinal Cord Injuries; Taurochenodeoxycholic Acid

Depression is a common psychiatric disorder with heavy economic and social burdens. Searching new agents with better antidepressant-like activities is of great significance for depression therapy. Tauroursodeoxycholic acid (TUDCA), a clinical drug for gallstone treatment, possesses neuroprotective effects in different brain disorders. However, whether it affects depression remains unclear. We addressed this issue by evaluating the effect of TUDCA on depression induced by chronic unpredictable stress (CUS). Results showed that TUDCA treatment at 200 but not 100 mg/kg prevented the 5 weeks of CUS-induced increases in the immobile time of C57BL6/J mice in the experiments of forced swimming test and tail suspension test as well as the CUS-induced decrease in sucrose intake and crossing numbers in the open-field test, and did not enhance the antidepressant-like effect of fluoxetine. Attenuation of neuroinflammation may be involved in the antidepressant-like effect of TUDCA, as TUDCA treatment (200 mg/kg) normalized the levels of tumor necrosis factor-α and interleukin-6 in both hippocampus and prefrontal cortex. The increases in inflammasome and microglial activation markers, including interleukin-β, nod-like receptor protein 3, and Iba-1, in CUS-treated mice were reduced by TUDCA treatment (200 mg/kg). TUDCA treatment (200 mg/kg) also normalized the changes in markers reflecting the oxidative-nitrosative and endoplasmic reticulum (ER) stress induced by CUS, such as nitric oxide, reduced glutathione, malondialdehyde, glucose-regulated protein 78, and C/EBP homologous protein. These results revealed that TUDCA improved the CUS-induced depression-like behaviors likely through attenuation of neuroinflammation, oxido-nitrosative, and ER stress.

Topics: Animals; Antidepressive Agents; Depression; Disease Models, Animal; Endoplasmic Reticulum Stress; Fluoxetine; Hindlimb Suspension; Hippocampus; Male; Mice; Mice, Inbred C57BL; Neuroprotective Agents; Nitrosative Stress; Oxidative Stress; Prefrontal Cortex; Stress, Psychological; Swimming; Taurochenodeoxycholic Acid

Parkinson's disease (PD) is characterized by severe motor symptoms, and currently there is no treatment that retards disease progression or reverses damage prior to the time of clinical diagnosis. Tauroursodeoxycholic acid (TUDCA) is neuroprotective in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) mouse model of PD; however, its effect in PD motor symptoms has never been addressed. In the present work, an extensive behavior analysis was performed to better characterize the MPTP model of PD and to evaluate the effects of TUDCA in the prevention/improvement of mice phenotype. MPTP induced significant alterations in general motor performance paradigms, including increased latency in the motor swimming, adhesive removal and pole tests, as well as altered gait, foot dragging, and tremors. TUDCA administration, either before or after MPTP, significantly reduced the swimming latency, improved gait quality, and decreased foot dragging. Importantly, TUDCA was also effective in the prevention of typical parkinsonian symptoms such as spontaneous activity, ability to initiate movement and tremors. Accordingly, TUDCA prevented MPTP-induced decrease of dopaminergic fibers and ATP levels, mitochondrial dysfunction and neuroinflammation. Overall, MPTP-injected mice presented motor symptoms that are aggravated throughout time, resembling human parkinsonism, whereas PD motor symptoms were absent or mild in TUDCA-treated animals, and no aggravation was observed in any parameter. The thorough demonstration of improvement of PD symptoms together with the demonstration of the pathways triggered by TUDCA supports a subsequent clinical trial in humans and future validation of the application of this bile acid in PD.

Topics: 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine; Animals; Disease Models, Animal; Gait; Hindlimb; Homeostasis; Inflammation; Male; Mice; Mice, Inbred C57BL; Mitochondria; Motor Activity; Movement; Neostriatum; Nerve Degeneration; Neuroglia; Neuroprotective Agents; Parkinson Disease; Taurochenodeoxycholic Acid; Tremor

Serum starvation is a routine protocol for synchronizing nuclear donor cells to G0/G1 phase during somatic cell nuclear transfer (SCNT). However, abrupt serum deprivation can cause serious stress to the cells cultured in vitro, which might result in endoplasmic reticulum (ER) stress, chromosome damage, and finally reduce the success rate of SCNT. In the present study, the effects of tauroursodeoxycholic acid (TUDCA), an effective ER stress-relieving drug, on the nuclear donor cells under serum deprivation condition as well as following SCNT procedures were first assessed in the bovine. The results showed that TUDCA significantly reduced ER stress and cell apoptosis in those nuclear donor cells. Moreover, it significantly decreased the expression of Hdac1 and Dnmt1, and increased the level of H3K9 acetylation in nuclear donor cells compared with control group. SCNT reconstructed embryos cloned from TUDCA-treated donor cells showed significantly higher fusion, cleavage, blastocyst formation rate, total cell number in day 7 blastocysts, and lower apoptotic index than that from control group. In addition, the expression of Hdac1, Dnmt1 and Bax was significantly lower in blastocysts derived from TUDCA-treated donor cells than that from control group. In conclusion, TUDCA significantly reduced the ER stress of nuclear donor cells under serum starvation condition, and significantly improved the developmental competence of following SCNT reconstructed embryos when these TUDCA-treated cells were used as the nuclear donors.

Topics: Apoptosis; Cell Cycle; Endoplasmic Reticulum Stress; Food Deprivation; Humans; Stress, Physiological; Taurochenodeoxycholic Acid

The current study mainly aims to evaluate the effects of ibrutinib on endoplasmic reticulum stress (ERS)-induced apoptosis in Reh cells, which may shed light on the treatment of acute lymphoblastic leukemia (ALL) among children. In line with previous studies, our data show that ibrutinib significantly suppressed Reh cell viability in a time- and dose-dependent manner. We further evaluated the role of ibrutinib on Reh cell colony formation and apoptosis. Ibrutinib inhibited clonogenic capacity and induced Reh cell apoptosis, suggesting an anti-tumor effects of ibrutinib in the progression of ALL. Further study showed that ibrutinib treatment increased ERS-related protein expression, including Bip, ATF4 and CHOP, suggesting the induction of ER-stress in Reh cells. More importantly, once ER-stress was suppressed by tauroursodeoxycholic acid (TUDCA), an ER-stress inhibitor, the upregulation of Bip, ATF4, CHOP, cleaved-caspase3 and cleaved-PARP after ibrutinib treatment was partially reversed, suggesting that induction of ALL cell apoptosis by ibrutinib was partially attributed to activation of ER stress. In summary, we showed novel data that ER-stress induced cell apoptosis plays a key role in the therapeutic effects of ibrutinib on ALL cell malignancies.

Topics: Activating Transcription Factor 4; Adenine; Apoptosis; Caspase 3; Cell Line, Tumor; Cell Survival; Endoplasmic Reticulum; Endoplasmic Reticulum Chaperone BiP; Endoplasmic Reticulum Stress; Heat-Shock Proteins; Humans; Piperidines; Poly (ADP-Ribose) Polymerase-1; Precursor Cell Lymphoblastic Leukemia-Lymphoma; Protein Kinase Inhibitors; Pyrazoles; Pyrimidines; Taurochenodeoxycholic Acid; Transcription Factor CHOP

Ischemia-reperfusion (I/R)-induced acute kidney injury (AKI) not only prolongs the length of hospital stay, but also seriously affects the patient's survival rate. Although our previous investigation has verified that reactive oxygen species (ROS) transferred through gap junction composed of connexin32 (Cx32) contributed to AKI, its underlying mechanisms were not fully understood and viable preventive or therapeutic regimens were still lacking. Among various mechanisms involved in organs I/R-induced injuries, endoplasmic reticulum stress (ERS)-related apoptosis is currently considered to be an important participant. Thus, in present study, we focused on the underlying mechanisms of I/R-induced AKI, and postulated that Cx32 mediated ROS/ERS/apoptosis signal pathway activation played an important part in I/R-induced AKI.. We established renal I/R models with Cx32. Renal damage was progressively exacerbated in a time-dependent manner at the reperfusion stage, that was consistent with the alternation of ERS activation, including glucose regulated protein 78 (BiP/GRP78), X box-binding protein1, and C/EBP homologous protein expression. TUDCA or 4-PBA application attenuated I/R-induced ERS activation and protected against renal tubular epithelial cells apoptosis and renal damage. Cx32 deficiency decreased ROS generation and distribution between the neighboring cells, which attenuated I/R-induced ERS activation, and improved cell apoptosis and renal damage.. Cx32 mediated ROS/ERS/apoptosis signal pathway activation played an important part in I/R-induced AKI. Cx32 deficiency, ROS elimination, and ERS inhibition all could protect against I/R-induced AKI.

Topics: Acetylcysteine; Acute Kidney Injury; Animals; Apoptosis; Connexins; Endoplasmic Reticulum Chaperone BiP; Endoplasmic Reticulum Stress; Epithelial Cells; Gap Junction beta-1 Protein; Gene Deletion; Gene Knockout Techniques; Kidney; Male; Mice, Inbred C57BL; Phenylbutyrates; Reactive Oxygen Species; Reperfusion Injury; Signal Transduction; Taurochenodeoxycholic Acid

Gentamycin is one of the most clinically used aminoglycoside antibiotics which induce intrinsic apoptosis of hair cells. Tauroursodeoxycholic acid (TUDCA) is known as safe cell-protective agent in disorders associated with apoptosis. We aimed to investigate the protective effects of TUDCA against gentamicin-induced ototoxicity. House Ear Institute-Organ of Corti 1(HEI-OC1) cells and explanted cochlear tissue were treated with gentamicin and TUDCA, followed by serial analyses including cell viability assay, hair cell staining, qPCR, ELISA and western blotting to determine the cell damage by the parameters relevant to cell apoptosis and endoplasmic reticulum stress. TUDCA significantly attenuated gentamicin-induced cell damage in cultured HEI-OC1 cells and explanted cochlear hair cells. TUDCA alleviated gentamicin-induced cell apoptosis, supported by the decreased Bax/Bcl2 ratio compared with that of gentamicin treated alone. TUDCA decreased gentamicin-induced nitric oxide production and protein nitration in both models. In addition, TUDCA suppressed gentamicin-induced endoplasmic reticulum stress as reflected by inversing the expression levels of Binding immunoglobulin protein (Bip), CCAAT/-enhancer-binding protein homologous protein (CHOP) and Caspase 3. TUDCA attenuated gentamicin-induced hair cell death by inhibiting protein nitration activation and ER stress, providing new insights into the new potential therapies for sensorineural deafness.

Topics: Animals; Anti-Bacterial Agents; Apoptosis; Biomarkers; Cell Line; Cell Survival; Cochlea; Endoplasmic Reticulum Stress; Gene Expression Regulation; Gentamicins; Hair Cells, Auditory; Hearing Loss, Sensorineural; Humans; Mice, Inbred BALB C; Microscopy, Electron, Scanning; Nitric Oxide Synthase Type II; Protective Agents; Protein Processing, Post-Translational; Protein Synthesis Inhibitors; Taurochenodeoxycholic Acid; Tissue Culture Techniques; Tyrosine

Prion diseases are a group of neurodegenerative diseases associated with the misfolding of the cellular prion protein (PrP

Topics: Animals; Anti-Infective Agents; Disease Models, Animal; Drug Administration Schedule; Female; Male; Mice; Prion Diseases; PrPSc Proteins; Survival Analysis; Taurochenodeoxycholic Acid; Time-to-Treatment; Treatment Failure; Ursodeoxycholic Acid

Bone marrow mesenchymal stem cells (BM-MSCs) are promising candidates for regenerative medicine purposes. The effect of obesity on the function of BM-MSCs is currently unknown. Here, we assessed how obesity affects the function of BM-MSCs and the role of endoplasmic reticulum (ER) stress and the unfolded protein response (UPR) therein. BM-MSCs were obtained from healthy donors with a normal (<25) or high (>30) body mass index (BMI). High-BMI BM-MSCs displayed severely impaired osteogenic and diminished adipogenic differentiation, decreased proliferation rates, increased senescence, and elevated expression of ER stress-related genes ATF4 and CHOP. Suppression of ER stress using tauroursodeoxycholic acid (TUDCA) and 4-phenylbutyrate (4-PBA) resulted in partial recovery of osteogenic differentiation capacity, with a significant increase in the expression of ALPL and improvement in the UPR. These data indicate that BMI is important during the selection of BM-MSC donors for regenerative medicine purposes and that application of high-BMI BM-MSCs with TUDCA or 4-PBA may improve stem cell function. However, whether this improvement can be translated into an in vivo clinical advantage remains to be assessed.

Topics: Activating Transcription Factor 4; Adipogenesis; Adolescent; Adult; Alkaline Phosphatase; Body Mass Index; Cell Differentiation; Cell Proliferation; Cellular Senescence; Child; Endoplasmic Reticulum Stress; Female; Gene Expression Regulation, Developmental; Humans; Male; Mesenchymal Stem Cell Transplantation; Mesenchymal Stem Cells; Middle Aged; Obesity; Osteogenesis; Phenylbutyrates; Regenerative Medicine; Taurochenodeoxycholic Acid; Tissue Donors; Transcription Factor CHOP; Unfolded Protein Response; Young Adult

Topics: Animals; Disease Models, Animal; Excitatory Amino Acid Antagonists; Gyrus Cinguli; Male; Neuralgia; Neurons; Rats; Rats, Sprague-Dawley; Receptors, N-Methyl-D-Aspartate; Taurochenodeoxycholic Acid

Ovarian surface epithelium (OSE) forms a single layer of mostly cuboidal cells on surface of mammalian ovaries that is inherently exposed to cell stress evoked by tissue damage every ovulation and declines morphologically after menopause. Endoplasmic reticulum (ER) is a principal cell organelle involved in proteosynthesis, but also integrating various stress signals. ER stress evokes a conserved signaling pathway, the unfolded protein response (UPR), leading to cell death or adaptation to stress conditions. In this work, we document that mouse OSE suffers from ER stress during replicative senescence in vitro, develops abnormalities in ER and initiates UPR. Attenuation of ER stress in senescent OSE by tauroursodeoxycholic acid (TUDCA) reconditions ER architecture and leads to delayed onset of senescence. In summary, we show for the first time a mutual molecular link between ER stress response and replicative senescence leading to phenotypic changes of non-malignant ovarian surface epithelium.

Topics: Animals; Cellular Senescence; Down-Regulation; Endoplasmic Reticulum Stress; Epithelium; Female; Mice; Ovary; RNA, Messenger; Taurochenodeoxycholic Acid; Telomere Shortening; Tunicamycin; Up-Regulation

Endoplasmic reticulum (ER) stress is an important event in atherosclerosis. Recent studies have shown that ER stress deregulates cholesterol metabolism via multiple pathways. This study aimed to determine the relationship between ER stress and lipid metabolism and to verify that upregulation of miR-33 is involved in this process.. An atherosclerosis model was established in apolipoprotein E-deficient (ApoE-/-) mice fed a Western diet, and THP-1 derived macrophages were used in this study. Hematoxylin-eosin and Oil Red O staining were used to quantify the atherosclerotic plaques. 1,1'-Dioctadecyl-3,3,3',3'-tetramethylindocarbocyanine perchlorate labeled oxidized low-density lipoprotein binding assay and a Cholesterol Efflux Fluorometric Assay Kit were used to observe cholesterol uptake and efflux. The mRNA and protein levels of biomarkers associated with ER stress and cholesterol metabolism in atherosclerotic plaques and macrophages were evaluated by real-time PCR and western blotting, respectively. Immunofluorescence was used to observe alterations of ABCA1 localization. Small interfering RNAs were used to knock down CHOP and miR-33 in macrophages to alter CHOP and miR-33 expression.. Atherosclerotic lesions and systemic lipid levels were ameliorated after inhibition of ER stress (tauroursodeoxycholic acid) in vivo. In vitro studies confirmed that ER stress regulated the lipid catabolism of macrophages by promoting cholesterol uptake, inhibiting cholesterol efflux, and modulating the expression of related transporters. CHOP contributed to lipid metabolism disorder following ER stress. Furthermore, over-expression of miR-33 was involved in ER stress that induced lipid metabolism disorder in macrophages. These findings support a model of ER stress induction by oxidized low-density lipoprotein that affects macrophage lipid catabolism disorder.. Our data shed new light on the relationship between ER stress and lipid metabolism in vivo and in vitro, and confirm that upregulation of miR-33 is involved in this process. The relationship between ER stress and miR-33 represents a novel target for the treatment of atherosclerosis.

Topics: Animals; Antagomirs; Apolipoproteins E; Atherosclerosis; ATP Binding Cassette Transporter 1; Cell Line; Cholesterol; Endoplasmic Reticulum Stress; Humans; Lipid Metabolism; Macrophages; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; MicroRNAs; RNA Interference; RNA, Small Interfering; Taurochenodeoxycholic Acid; Transcription Factor CHOP

Mounting evidence shows that ROS regulation by various antioxidants is essential for the expression of enzymes involved in steroidogenesis and maintenance of progesterone production by the corpus luteum (CL). However, the underlying mechanisms of peroxiredoxin 1 (PRDX1), an antioxidant enzyme, in luteal function for progesterone production in mice have not been reported. The aim of this study was to evaluate the functional link between PRDX1 and progesterone production in the CL of Prdx1 knockout (K/O) mice in the functional stage of CL.. The expression pattern of the unfolded protein response (UPR) signaling pathways, endoplasmic reticulum (ER) stress-induced apoptosis related genes and peroxiredoxins 1 (PRDX1) were investigated by western blotting analysis in CL tissue of 10 weeks mice during functional stage of CL. The protein levels of these genes after ER-stress inducer tunicamycin (Tm), ER-stress inhibitor tauroursodeoxycholic acid (TUDCA) and ROS scavenger, N-acetylcysteine (NAC) stimulation by intraperitoneal (i.p) injection were also investigated in CL tissue of wild type (WT) mice. Finally, we examined progesterone production and UPR signaling related gene expression in CL tissue of Prdx1 K/O mice.. We demonstrated that PRDX1 deficiency in the functional stage activates the UPR signaling pathways in response to ER stress-induced apoptosis. Interestingly, CL number, serum progesterone levels, and steroidogenic enzyme expression in Prdx1 K/O mice decreased significantly, compared to those in wild type mice. Levels of UPR signaling pathway markers (GRP78/BIP, P50ATF6, and phosphorylated (p)-eIF2) and ER-stress associated apoptotic factors (CHOP, p-JNK, and cleaved caspase-3) were dramatically increased in the CL tissue of Prdx1 K/O mice. In addition, administration of the NAC, reduced progesterone production and activated ER-stress-induced UPR signaling in the CL tissue obtained from the ovary of Prdx1 K/O mice. Taken together, these results indicated that reduction in serum progesterone levels and activation of ER-stress-induced UPR signaling are restored by NAC injection in the CL of Prdx1 K/O mice.. These observations provide the first evidence regarding the basic mechanisms connecting PRDX1 and progesterone production in the functional stage of CL.

Topics: Acetylcysteine; Animals; Apoptosis; Cholagogues and Choleretics; Corpus Luteum; Endoplasmic Reticulum Chaperone BiP; Endoplasmic Reticulum Stress; Female; Free Radical Scavengers; Gene Expression; Mice, Inbred C57BL; Mice, Knockout; Peroxiredoxins; Progesterone; Signal Transduction; Taurochenodeoxycholic Acid; Unfolded Protein Response

The aim of this study is to investigate the protective effect and the mechanism of tauroursodeoxycholic acid (TUDCA) against hepatic ischemia reperfusion (IR) injury. Male Balb/c mice were intraperitoneally injected with tauroursodeoxycholic acid (400 mg/kg) or saline solution, once per day for 3 days before surgery, and then the model of hepatic I/R injury was established. Blood and liver samples were collected from each group at 3, 6, and 24 h after surgery. Liver pathological changes, liver function, hepatocyte apoptosis and proinflammatory factors were detected. KCs were extracted, cultured and treated with TUDCA or phosphate-buffered saline (PBS) for 24 h, and then viability and phagocytosis were examined. Additionally, IRE1α/TRAF2/NF-κB pathway activity and AML cell apoptosis were detected. The results showed that TUDCA alleviated hepatic I/R injury, the level of liver function markers, and hepatocyte apoptosis in vivo. Furthermore, the proinflammatory effects of KCs were suppressed by down-regulating IRE1α/TRAF2/NF-κB pathway activity in vivo. TUDCA dose-dependently suppressed the expression of inflammatory factors and IRE1α/TRAF2/NF-κB pathway activity in vitro, consistent with the in vivo results. Therefore, TUDCA can effectively alleviate hepatic IR injury by down-regulating the activity of the IRE1α/TRAF2/NF-κB pathway to suppress the function of KCs.

Topics: Animals; Apoptosis; Cell Line, Tumor; Cell Survival; Coculture Techniques; Cytokines; Cytoprotection; Disease Models, Animal; Dose-Response Relationship, Drug; Endoplasmic Reticulum Stress; Endoribonucleases; Inflammation Mediators; Kupffer Cells; Leukemia, Myeloid, Acute; Liver; Liver Diseases; Male; Mice, Inbred BALB C; NF-kappa B; Protein Serine-Threonine Kinases; Reperfusion Injury; Signal Transduction; Taurochenodeoxycholic Acid; Time Factors; TNF Receptor-Associated Factor 2

Cumulus-free in vitro maturation (IVM) provides a powerful tool to manipulate immature oocytes, but IVM oocytes lead to poor development after fertilization. Supplementation of the culture medium with tauroursodeoxycholic acid (TUDCA), a bile acid, has been reported to improve the development of embryos derived from in vivo fertilized (IVF) embryos after in vitro culture (IVC) by attenuating endoplasmic reticulum stress. However, it remains unclear if TUDCA can improve development of IVM-IVF embryos. Here, we examined whether TUDCA treatment could improve embryonic development during or after IVM. Immature GV oocytes collected from ovaries of ICR female mice that were free from cumulus cells were subjected to IVM in αMEM containing 5% FBS for 16 h. TUDCA was added to the media at varying concentrations (0-1000 μM) during IVM and IVC. TUDCA treatment during IVM reduced both MII and pronuclear (PN) rates but did not affect blastocyst rates of fertilized embryos. In contrast, TUDCA treatment during IVC significantly increased blastocyst formation rates in a concentration dependent manner. Finally, embryo transfer after TUDCA treatment revealed a significant improvement in the rates of offspring production (15% with 1000 μM TUDCA vs. 6.0% control). These results show that treatment with 1000 μM of TUDCA significantly can improve poor embryonic development of cumulus-free IVM-IVF embryos.

Topics: Animals; Antiviral Agents; Cumulus Cells; Embryo Culture Techniques; Embryo Transfer; Embryonic Development; Endoplasmic Reticulum Stress; Female; Fertilization in Vitro; In Vitro Oocyte Maturation Techniques; Mice; Mice, Inbred ICR; Oocytes; Pregnancy; Taurochenodeoxycholic Acid

RING finger 186 (RNF186) is involved in the process of endoplasmic reticulum (ER)-stress-mediated apoptosis and inflammation of different cell types, such as HeLa cells and colon epithelial cells. However, the physiological and functional roles of RNF186 in peripheral tissues remain largely unknown. In the current study, we investigate the physiological function of RNF186 in the regulation of ER stress with respect to its biological roles in regulating insulin sensitivity in mouse primary hepatocytes. RNF186 expression is induced in the livers of diabetic, obese and diet-induced obese (DIO) mice. Mouse primary hepatocytes were isolated and treated with Ad-RNF186 or Ad-GFP. The results suggest that overexpression of RNF186 increases the protein levels of the ER stress sensors inositol requiring kinase 1 (IRE1) and C/EBP homologous protein (CHOP) protein, as well as the phosphorylation level of eukaryotic initiation factor 2α (eIF2α), in mouse primary hepatocytes. This effect impedes the action of insulin through c-Jun N-terminal kinase (JNK)-mediated phosphorylation of insulin receptor substrate 1 (IRS1). Furthermore, overexpression of RNF186 also significantly increases the levels of proinflammatory cytokines, including TNFα, IL-6 and MCP1. In addition, tauroursodeoxycholic acid (TUDCA), an ER stress inhibitor, alleviates the expression of ER stress markers induced by RNF186 overexpression. Taken together, the results of the present study show that overexpression of RNF186 induces ER stress and impairs insulin signalling in mouse primary hepatocytes, suggesting that RNF186 merits further investigation as a potential therapeutic target for treatment of insulin-resistance-associated metabolic diseases.

Topics: Animals; Chemokine CCL2; Diabetes Mellitus; Diet, High-Fat; Endoplasmic Reticulum Stress; Eukaryotic Initiation Factor-2B; Hep G2 Cells; Hepatocytes; Humans; Insulin; Insulin Resistance; Interleukin-6; Liver; Male; Membrane Proteins; Mice; Mice, Inbred C57BL; Mice, Obese; Protein Serine-Threonine Kinases; Taurochenodeoxycholic Acid; Transcription Factor CHOP; Tumor Necrosis Factor-alpha; Ubiquitin-Protein Ligases

Diabetic nephropathy (DN) is a major complication of diabetes, and the dysfunction of endoplasmic reticulum (ER) plays an important role in its pathogenesis. ERp44, an ER resident chaperone protein, has been implicated in the modulation of ER stress, however, its role and mechanism in DN are not determined. Here, we show that ERp44 expression is upregulated in the glomeruli of db/db mice, a rodent model of type 2 diabetes. When ERp44 is depleted by in vivo shRNA-mediated knockdown, the features associated with DN including albuminuria level and glomerular basement membrane (GBM) thickness are aggravated, therefore suggesting a detrimental role of ERp44 depletion in DN progression. We further show that ERp44 depletion exacerbates ER stress in DN in db/db mice, and that attenuating ER stress with the chemical chaperone TUDCA remarkably diminishes the aggravated DN features caused by ERp44 depletion. These results suggest that the exacerbated ER stress is a critical factor for the detrimental effect of ERp44 depletion on DN progression in db/db mice. Thus, our study links the role of ERp44 in DN with ER stress regulation and may offer a potential therapeutic strategy to interfere DN progression.

Topics: Animals; Diabetes Mellitus, Experimental; Diabetes Mellitus, Type 2; Diabetic Nephropathies; Endoplasmic Reticulum Stress; Kidney Glomerulus; Membrane Proteins; Mice, Inbred C57BL; Molecular Chaperones; Taurochenodeoxycholic Acid

Topics: Animals; Cell Line; Cell Survival; Cytoprotection; Diabetes Mellitus, Type 2; Endoplasmic Reticulum Chaperone BiP; Endoplasmic Reticulum Stress; Eukaryotic Initiation Factor-2; Exenatide; Glucagon-Like Peptide-1 Receptor; Heat-Shock Proteins; Hypoglycemic Agents; Insulin; Insulin-Secreting Cells; Male; Mice; Mice, Inbred C57BL; Protective Agents; Rats; Taurochenodeoxycholic Acid

Topics: Bile Acids and Salts; Biotransformation; Clostridium; Escherichia coli; Escherichia coli Proteins; Fermentation; Hydrogen-Ion Concentration; Hydroxysteroid Dehydrogenases; Microorganisms, Genetically-Modified; Selection, Genetic; Taurochenodeoxycholic Acid

Pressure overload in the heart induces pathological hypertrophy and is associated with cardiac dysfunction. Apoptosis and fibrosis signaling initiated by the endoplasmic reticulum stress (ERS) is known to contribute to these maladaptive effects. The aim of this study was to investigate whether reduction of ERS by a known chemical chaperone, tauroursodeoxycholic acid (TUDCA) can attenuate pressure overload-induced cardiac remodeling in a mouse model of transverse aortic constriction (TAC). Oral administration of TUDCA at a dose of 300 mg/kg body weight (BW) in the TUDCA-TAC group reduced ERS markers (GRP78, p-PERK, and p-eIf2α), compared to the Vehicle (Veh)-TAC group. TUDCA administration, for 4 weeks after TAC significantly reduced cardiac hypertrophy as shown by the reduced heart weight (HW) to BW ratio, and expression of hypertrophic marker genes (ANF, BNP, and α-SKA). Masson's trichrome staining showed that myocardial fibrosis and collagen deposition were also significantly reduced in the TUDCA-TAC group. We also found that TUDCA significantly decreased expression of TGF-β signaling proteins and collagen isoforms. TUDCA administration also reduced cardiac apoptosis and the related proteins in the TUDCA-TAC group. Microarray analysis followed by gene ontology (GO) and pathway analysis demonstrated that extracellular matrix genes responsible for hypertrophy and fibrosis, and mitochondrial genes responsible for apoptosis and fatty acid metabolism were significantly altered in the Veh-TAC group, but the alterations were normalized in the TUDCA-TAC group, suggesting potential of TUDCA in treatment of heart diseases related to pressure-overload.

Topics: Animals; Disease Models, Animal; Dose-Response Relationship, Drug; Endoplasmic Reticulum Chaperone BiP; Endoplasmic Reticulum Stress; Gene Expression; Male; Mice; Taurochenodeoxycholic Acid; Ventricular Remodeling

Tauroursodeoxycholic acid (TUDCA) has been used to treat many diseases effectively. 7α-hydroxysteroid dehydrogenase (7α-HSDH) and 7β-hydroxysteroid dehydrogenase (7β-HSDH) are two key enzymes that drive the efficient biosynthesis of TUDCA from taurochenodeoxycholic acid (TCDCA) in vitro. In this study, a metagenomic approach was used to isolate 7α- and 7β-HSDHs from fecal samples of black bears. Five new 7α-HSDHs and one new 7β-HSDH enzyme were discovered and identified from the gut microbiota of black bears, and four of them presented good enzymatic properties. Our data also suggest cooperation in the biotransformation of TUDCA by the gut microbiota in black bears. In conclusion, this work expands the natural enzyme bank of HSDHs, provides promising candidate enzymes for application in the biosynthesis TUDCA and the epimerization reaction of bile acids at the C-7 position, and provides a data set for the discovery of novel enzymes in the gut micriobiome of black bears.

Topics: Amino Acid Sequence; Animals; Bacteria; Bile Acids and Salts; Cloning, Molecular; DNA, Bacterial; Feces; Gastrointestinal Microbiome; Hydroxysteroid Dehydrogenases; Kinetics; Metagenomics; Protein Stability; Recombinant Proteins; Sequence Alignment; Stereoisomerism; Taurochenodeoxycholic Acid; Ursidae

Classical osteogenesis imperfecta (OI) is a bone disease caused by type I collagen mutations and characterized by bone fragility, frequent fractures in absence of trauma and growth deficiency. No definitive cure is available for OI and to develop novel drug therapies, taking advantage of a repositioning strategy, the small teleost zebrafish (Danio rerio) is a particularly appealing model. Its small size, high proliferative rate, embryo transparency and small amount of drug required make zebrafish the model of choice for drug screening studies, when a valid disease model is available. We performed a deep characterization of the zebrafish mutant Chihuahua, that carries a G574D (p.G736D) substitution in the α1 chain of type I collagen. We successfully validated it as a model for classical OI. Growth of mutants was delayed compared with WT. X-ray, µCT, alizarin red/alcian blue and calcein staining revealed severe skeletal deformity, presence of fractures and delayed mineralization. Type I collagen extracted from different tissues showed abnormal electrophoretic migration and low melting temperature. The presence of endoplasmic reticulum (ER) enlargement due to mutant collagen retention in osteoblasts and fibroblasts of mutant fish was shown by electron and confocal microscopy. Two chemical chaperones, 4PBA and TUDCA, were used to ameliorate the cellular stress and indeed 4PBA ameliorated bone mineralization in larvae and skeletal deformities in adult, mainly acting on reducing ER cisternae size and favoring collagen secretion. In conclusion, our data demonstrated that ER stress is a novel target to ameliorate OI phenotype; chemical chaperones such as 4PBA may be, alone or in combination, a new class of molecules to be further investigated for OI treatment.

Topics: Animals; Calcification, Physiologic; Cells, Cultured; Collagen; Collagen Type I; Fibroblasts; Models, Animal; Molecular Chaperones; Mutation; Osteoblasts; Osteogenesis Imperfecta; Phenylbutyrates; Protein Folding; Taurochenodeoxycholic Acid; Zebrafish

Successful drug therapies for treating ocular diseases require effective concentrations of neuroprotective compounds maintained over time at the site of action. The purpose of this work was to assess the efficacy of intravitreal controlled delivery of tauroursodeoxycholic acid (TUDCA) encapsulated in poly(D,L-lactic-co-glycolic acid) (PLGA) microspheres for the treatment of the retina in a rat model of retinitis pigmentosa. PLGA microspheres (MSs) containing TUDCA were produced by the O/W emulsion-solvent evaporation technique. Particle size and morphology were assessed by light scattering and scanning electronic microscopy, respectively. Homozygous P23H line 3 rats received a treatment of intravitreal injections of TUDCA-PLGA MSs. Retinal function was assessed by electroretinography at P30, P60, P90 and P120. The density, structure and synaptic contacts of retinal neurons were analyzed using immunofluorescence and confocal microscopy at P90 and P120. TUDCA-loaded PLGA MSs were spherical, with a smooth surface. The production yield was 78%, the MSs mean particle size was 23 μm and the drug loading resulted 12.5 ± 0.8 μg TUDCA/mg MSs. MSs were able to deliver the loaded active compound in a gradual and progressive manner over the 28-day in vitro release study. Scotopic electroretinografic responses showed increased ERG a- and b-wave amplitudes in TUDCA-PLGA-MSs-treated eyes as compared to those injected with unloaded PLGA particles. TUDCA-PLGA-MSs-treated eyes showed more photoreceptor rows than controls. The synaptic contacts of photoreceptors with bipolar and horizontal cells were also preserved in P23H rats treated with TUDCA-PLGA MSs. This work indicates that the slow and continuous delivery of TUDCA from PLGA-MSs has potential neuroprotective effects that could constitute a suitable therapy to prevent neurodegeneration and visual loss in retinitis pigmentosa.

Topics: Animals; Blindness; Delayed-Action Preparations; Disease Models, Animal; Electroretinography; Lactic Acid; Microspheres; Neuroprotective Agents; Particle Size; Photoreceptor Cells, Vertebrate; Polyglycolic Acid; Polylactic Acid-Polyglycolic Acid Copolymer; Rats; Rats, Sprague-Dawley; Retina; Retinal Degeneration; Retinitis Pigmentosa; Taurochenodeoxycholic Acid

Topics: alpha-Synuclein; Animals; Brain; Cell Death; Cell Line; Glutathione Peroxidase; Lipid Peroxidation; Male; Mice; Mice, Inbred C57BL; MPTP Poisoning; NF-E2-Related Factor 2; Oxidative Stress; Parkinson Disease, Secondary; Reactive Oxygen Species; RNA, Small Interfering; Taurochenodeoxycholic Acid

Impaired mitochondrial function and generation of reactive oxygen species are deeply implicated in Parkinson's disease progression. Indeed, mutations in genes that affect mitochondrial function account for most of the familial cases of the disease, and post mortem studies in sporadic PD patients brains revealed increased signs of oxidative stress. Moreover, exposure to 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), a mitochondrial complex I inhibitor, leads to clinical symptoms similar to sporadic PD. The bile acid tauroursodeoxycholic acid (TUDCA) is an anti-apoptotic molecule shown to protect against MPTP-induced neurodegeneration in mice, but the mechanisms involved are still incompletely identified. Herein we used MPTP-treated mice, as well as primary cultures of mice cortical neurons and SH-SY5Y cells treated with MPP

Topics: Animals; Antioxidants; Male; Mice; Neuroprotective Agents; Parkinsonian Disorders; Taurochenodeoxycholic Acid; Ubiquitin-Protein Ligases

Stress induced BSA (bovine serum albumin) protein aggregation is effectively mitigated in vitro by TUDCA (tauroursodeoxycholic acid) than by PBA (4- phenylbutyric acid), chemical chaperones approved by FDA for the treatment of biliary cirrhosis and urea cycle disorders respectively. TUDCA, unlike PBA, enhances trypsin mediated digestion of BSA. TUDCA activates PERK, an ER-resident kinase that phosphorylates the alpha-subunit of eukaryotic initiation factor2 (eIF2α) and promotes the expression of activated transcription factor 4 (ATF4) in HepG2 cells. In contrast, PBA induced eIF2α phosphorylation is not mediated by PERK activation and results in low ATF4 expression. Neither chaperones promote expression of BiP, an ER chaperone, and CHOP (C/EBP homologous protein), downstream target of eIF2α-ATF4 pathway. Both chaperones mitigate tunicamycin induced PERK-eIF2α-ATF4-CHOP arm of UPR and expression of BiP. TUDCA, unlike PBA does not decrease cell viability and it also mitigates tunicamycin, UV-irradiation and PBA induced PARP (poly ADP-ribose polymerase) cleavage and cell death. These findings therefore suggest that TUDCA's antiapoptotic activity to protect HepG2 cells and PBA's activity that limits tumor cell progression may be important while considering their therapeutic potential.

Topics: Activating Transcription Factor 4; Apoptosis; eIF-2 Kinase; Endoplasmic Reticulum Stress; Eukaryotic Initiation Factor-2; Hep G2 Cells; Humans; Molecular Chaperones; Molecular Sequence Annotation; Phenylbutyrates; Poly(ADP-ribose) Polymerases; Taurochenodeoxycholic Acid; Tunicamycin

Topics: Adaptation, Physiological; Adenosine Triphosphate; Alanine Transaminase; Alkaline Phosphatase; Antibiotics, Antitubercular; Aspartate Aminotransferases; ATP Binding Cassette Transporter, Subfamily B; ATP Binding Cassette Transporter, Subfamily B, Member 11; Bilirubin; Endoplasmic Reticulum Chaperone BiP; gamma-Glutamyltransferase; Gene Expression Regulation; Hep G2 Cells; Humans; L-Lactate Dehydrogenase; Liver-Specific Organic Anion Transporter 1; Membrane Transport Proteins; Multidrug Resistance-Associated Protein 2; Multidrug Resistance-Associated Proteins; NF-E2-Related Factor 2; Organic Anion Transporters, Sodium-Dependent; Rifampin; RNA, Small Interfering; Signal Transduction; Stress, Physiological; Symporters; Taurochenodeoxycholic Acid

Elaiophylin is a natural compound and a novel and potent inhibitor of late stage autophagy with outstanding antitumor activity in human ovarian cancer cells. However, the possible biologic effects and functional linkage between elaiophylin and multiple myeloma (MM) have not been explored. This study aimed to assess the effect of elaiophylin on MM cells with mutant TP53 and the possible molecular mechanism. The results suggested that elaiophylin exerted anti-myeloma activity by inducing apoptosis and proliferation arrest. As expected, elaiophylin blocked autophagy flux in MM cells. Subsequently, persistent activation of endoplasmic reticulum (ER) stress was induced. Moreover, the apoptotic effect was to some extent attenuated by the ER stress inhibitor tauroursodeoxycholic acid (TUDCA). Further studies indicated that elaiophylin effectively suppressed MM cell growth without obvious side effects in zebrafish embryo and mouse xenograft models. Taken together, our data are the first to demonstrate that exposure of human MM cells with mutant TP53 to elaiophylin blocked autophagy flux and thus induced cell death, which partially involved ER stress-associated apoptosis. Targeted disruption of the cellular protein handling system by elaiophylin is therefore a promising therapeutic strategy for overcoming incurable MM, even when TP53 mutations are present.

Topics: Animals; Antineoplastic Agents; Apoptosis; Autophagy; Cell Line, Tumor; Cell Proliferation; Endoplasmic Reticulum Stress; Female; Humans; Macrolides; Mice; Mice, Inbred C57BL; Mice, Inbred NOD; Mice, SCID; Multiple Myeloma; Mutation; Signal Transduction; Taurochenodeoxycholic Acid; Tumor Suppressor Protein p53; Xenograft Model Antitumor Assays; Zebrafish

Evaporative drying (ED) is an alternative technique for long-term preservation of mammalian sperm, which does not require liquid nitrogen or freeze-drying equipment, but offers advantages for storage and shipping at ambient temperature and low cost. However, the development of zygotes generated from these sperms was poor. Here, we demonstrated that the supplementation of tauroursodeoxycholic acid (TUDCA), an endogenous bile acid, during embryo culture improved the developmental competency of embryos derived from in vitro matured pig oocytes injected intracytoplasmically with boar ED spermatozoa by reducing the production of reactive oxygen species, the DNA degradation and fragmentation, and the expression of apoptosis-related gene Bax and Bak, and by increasing the transcription of anti-apoptosis gene Bcl-XL and Bcl-2. Furthermore, TUDCA treatment promoted the blastocyst quality manifested by the total cell numbers and the ratio of inner cell mass. Taken together, our data suggest that evaporative drying would be a potentially useful method for the routine preservation of boar sperm in combination with further optimization of subsequently embryo culture conditions.

Topics: Animals; Apoptosis; bcl-2 Homologous Antagonist-Killer Protein; bcl-2-Associated X Protein; Blastocyst; Desiccation; Embryo Culture Techniques; Embryo, Mammalian; Embryonic Development; In Vitro Oocyte Maturation Techniques; Male; Reactive Oxygen Species; RNA, Messenger; Sperm Injections, Intracytoplasmic; Spermatozoa; Swine; Taurochenodeoxycholic Acid

The interaction of IFN with specific membrane receptors that transduce death-inducing signals is considered to be the principle mechanism of IFN-induced cytotoxicity. In this study, the classic non-cell-autonomous cytotoxicity of IFN was augmented by cell-autonomous mechanisms that operated independently of the interaction of IFN with its receptors. Cells primed to produce IFN by 5-azacytidine (5-aza) underwent endoplasmic reticulum (ER) stress. The chemical chaperones tauroursodeoxycholate (TUDCA) and 4-phenylbutyrate (4-PBA), as well as the iron chelator ciclopirox (CPX), which reduces ER stress, alleviated the cytotoxicity of 5-aza. Ablation of CCAAT-enhancer-binding protein homologous protein (CHOP), the major ER stress-associated proapoptotic transcription factor, protected fibroblasts from 5-aza only when the cytotoxicity was examined cell autonomously. In a medium-transfer experiment in which the cell-autonomous effects of 5-aza was dissociated, CHOP ablation was incapable of modulating cytotoxicity; however, neutralization of IFN receptor was highly effective. Also the levels of caspase activation showed a distinct profile between the cell-autonomous and the medium-transfer experiments. We suggest that besides the classic paracrine mechanism, cell-autonomous mechanisms that involve induction of ER stress also participate. These results have implications in the development of anti-IFN-based therapies and expand the class of pathologic states that are viewed as protein-misfolding diseases.-Mihailidou, C., Papavassiliou, A. G., Kiaris, H. Cell-autonomous cytotoxicity of type I interferon response

Topics: Animals; Azacitidine; Blotting, Western; Cell Death; Cell Survival; Cells, Cultured; Ciclopirox; Endoplasmic Reticulum Stress; Enzyme-Linked Immunosorbent Assay; Interferon Type I; Mice; Mice, Inbred C57BL; Phenylbutyrates; Pyridones; Taurochenodeoxycholic Acid; Unfolded Protein Response

Endoplasmic reticulum (ER) stress has emerged as a potential mechanism contributing to diabetes and its comorbidities. However, the importance of ER stress in diabetic vascular dysfunction is unclear. The purpose of this study was to examine the effects of the ER stress inhibitor, tauroursodeoxycholic acid (TUDCA), on arterial stiffness and endothelial dysfunction in type 2 diabetic mice.. Carotid and mesenteric artery endothelial function were assessed via ex vivo pressure myography, and arterial stiffness was measured by aortic pulse wave velocity. The effects of TUDCA were examined both acutely (ex vivo) and chronically (250 mg/kg/day; i.p., 4 weeks).. Compared to control C57BL/6J mice, db/db (DB) mice did not display carotid artery endothelial dysfunction; however, mesenteric artery endothelial function was markedly impaired. Acute incubation and chronic administration of TUDCA improved endothelium-dependent dilation in DB mesenteric arteries, without affecting endothelium-independent dilation. Chronic TUDCA administration also reduced arterial stiffness and was associated with reductions in ER stress markers in aortic and perivascular adipose tissue.. These results suggest that ER stress may represent a novel cause of, and therapeutic target for, diabetic vascular dysfunction.

Topics: Animals; Carotid Arteries; Diabetes Mellitus, Type 2; Diabetic Angiopathies; Disease Models, Animal; Dose-Response Relationship, Drug; Endoplasmic Reticulum Stress; Endothelium, Vascular; Male; Mesenteric Arteries; Mice, Inbred C57BL; Myography; Pulse Wave Analysis; Taurochenodeoxycholic Acid; Vascular Stiffness; Vasodilation; Vasodilator Agents

Endoplasmic reticulum (ER) stress arises when excessive improperly folded proteins accumulate in the ER lumen. When ER stress occurs, the unfolded protein response (UPR) is subsequently activated to restore ER proteostasis. However, severe ER stress leads to apoptosis. Recent studies have suggested that cisplatin cytotoxicity may be related to ER stress. The purpose of this study was to determine whether ER stress participates in cochlear cell apoptosis in a cisplatin-induced ototoxicity rat model and to also determine the possible relationship between ER stress and hearing loss. Our results revealed that treatment with cisplatin upregulated the expression of active caspase-12 in cochlear cells, which is indicative of cisplatin-induced activation of ER-specific apoptosis. Increased expression of C/EBP homologous protein (CHOP) and cleaved caspase-9 suggested a close relationship between severe ER stress and mitochondria-dependent apoptosis in the cochlear cells of cisplatin-treated rats. In addition, we found that tauroursodeoxycholic acid (TUDCA), a promoter of ER proteostasis, had a protective effect on cisplatin-induced hearing loss. These results demonstrate that ER stress is involved in the cisplatin-induced apoptosis of cochlear cells in vivo.

Topics: Animals; Antineoplastic Agents; Apoptosis; Cisplatin; Cochlea; Endoplasmic Reticulum Stress; Hearing Loss; Male; Protective Agents; Rats; Rats, Sprague-Dawley; Taurochenodeoxycholic Acid; Unfolded Protein Response

Homozygous HLA-DR4/I-E transgenic mice (tgm) spontaneously developed colitis similar to human ulcerative colitis. We explored whether endoplasmic reticulum stress in colonic epithelial cells due to overexpression of HLA-DR4/I-E was involved in the pathogenesis of colitis.. Major histocompatibility complex class II transactivator-knockout (CIITAKO) background tgm were established to test the involvement of HLA-DR4/I-E expression in the pathogenesis of colitis. Histological and cellular analyses were performed and the effect of oral administration of the molecular chaperone tauroursodeoxycholic acid (TUDCA) and antibiotics were investigated. IgA content of feces and serum and presence of IgA-coated fecal bacteria were also investigated.. Aberrantly accumulated HLA-DR4/I-E molecules in colonic epithelial cells were observed only in the colitic homozygous tgm, which was accompanied by upregulation of the endoplasmic reticulum stress marker Binding immunoglobulin protein (BiP) and reduced mucus. Homozygous tgm with CIITAKO, and thus absent of HLA-DR4/I-E expression, did not develop colitis. Oral administration of TUDCA to homozygotes reduced HLA-DR4/I-E and BiP expression in colonic epithelial cells and restored the barrier function of the intestinal tract. The IgA content of feces and serum, and numbers of IgA-coated fecal bacteria were higher in the colitic tgm, and antibiotic administration suppressed the expression of HLA-DR4/I-E and colitis.. The pathogenesis of the colitis observed in the homozygous tgm was likely due to endoplasmic reticulum stress, resulting in goblet cell damage and compromised mucus production in the colonic epithelial cells in which HLA-DR4/I-E molecules were heavily accumulated. Commensal bacteria seemed to be involved in the accumulation of HLA-DR4/I-E, leading to development of the colitis.

Topics: Animals; Bacteria; CD4-Positive T-Lymphocytes; Colitis; Colon; Epithelial Cells; Female; HLA-DR4 Antigen; Homozygote; Immunoglobulin A; Male; Mice; Mice, Transgenic; Taurochenodeoxycholic Acid

Disruption of insulin secretion and clearance both contribute to obesity-induced hyperinsulinemia, though reduced insulin clearance seems to be the main factor. The liver is the major site for insulin degradation, a process mainly coordinated by the insulin-degrading enzyme (IDE). The beneficial effects of taurine conjugated bile acid (TUDCA) on insulin secretion as well as insulin sensitivity have been recently described. However, the possible role of TUDCA in insulin clearance had not yet been explored. Here, we demonstrated that 15 days treatment with TUDCA reestablished plasma insulin to physiological concentrations in high fat diet (HFD) mice, a phenomenon associated with increased insulin clearance and liver IDE expression. TUDCA also increased IDE expression in human hepatic cell line HepG2. This effect was not observed in the presence of an inhibitor of the hepatic membrane bile acid receptor, S1PR2, nor when its downstream proteins were inhibited, including IR, PI3K and Akt. These results indicate that treatment with TUDCA may be helpful to counteract obesity-induced hyperinsulinemia through increasing insulin clearance, likely through enhanced liver IDE expression in a mechanism dependent on S1PR2-Insulin pathway activation.

Topics: Animals; Diet, High-Fat; Hep G2 Cells; Humans; Hyperinsulinism; Insulin; Insulysin; Liver; Mice; Mice, Obese; Taurochenodeoxycholic Acid

Early-cleaving embryos are known to have better capacity to reach the blastocyst stage and produce better quality embryos compared to late-cleaving embryos. To investigate the significance of endoplasmic reticulum (ER) stress on early embryo cleavage kinetics and development, porcine embryos produced in vitro were separated into early- and late-cleaving groups and then cultured in the absence or presence of the ER stress inhibitor tauroursodeoxycholic acid (TUDCA). Developing embryos were collected at days 3 to 7 of culture for assessment of ER stress status, incidence of DNA double-strand breaks (DSBs), development and total cell number. In the absence of TUDCA treatment, late-cleaving embryos exhibited ER stress, higher incidence of DNA DSBs, as well as reductions in development to the blastocyst stage and total embryo cell numbers. Treatment of late-cleaving embryos with TUDCA mitigated these effects and markedly improved embryo quality and development. These results demonstrate the importance of stress coping responses in early developing embryos, and that reduction of ER stress is a potential means to improve embryo quality and developmental competence.

Topics: Animals; Blastocyst; DNA Damage; DNA Repair; Embryonic Development; Endoplasmic Reticulum Stress; Female; Real-Time Polymerase Chain Reaction; Swine; Taurochenodeoxycholic Acid

The chaperone GRP78/BiP (glucose-regulated protein 78 kDa/binding immunoglobulin protein) modulates protein folding in reply to cellular insults that lead to endoplasmic reticulum (ER) stress. This study investigated the role of hypothalamic GRP78 on energy balance, with particular interest in thermogenesis and browning of white adipose tissue (WAT). For this purpose, we used diet-induced obese rats and rats administered thapsigargin, and by combining metabolic, histologic, physiologic, pharmacologic, thermographic, and molecular techniques, we studied the effect of genetic manipulation of hypothalamic GRP78. Our data showed that rats fed a high-fat diet or that were centrally administered thapsigargin displayed hypothalamic ER stress, whereas genetic overexpression of GRP78 specifically in the ventromedial nucleus of the hypothalamus was sufficient to alleviate ER stress and to revert the obese and metabolic phenotype. Those effects were independent of feeding and leptin but were related to increased thermogenic activation of brown adipose tissue and induction of browning in WAT and could be reversed by antagonism of β3 adrenergic receptors. This evidence indicates that modulation of hypothalamic GRP78 activity may be a potential strategy against obesity and associated comorbidities.

Topics: Adipose Tissue, Brown; Adipose Tissue, White; Animals; Blotting, Western; Diet, High-Fat; Endoplasmic Reticulum Stress; Fatty Acids, Nonesterified; Hypothalamus; Immunohistochemistry; Male; Obesity; Rats; Rats, Sprague-Dawley; Real-Time Polymerase Chain Reaction; Taurochenodeoxycholic Acid; Temperature; Thermogenesis

Mitochondrial dysfunction has been deeply implicated in the pathogenesis of several neurodegenerative diseases. Thus, to keep a healthy mitochondrial population, a balanced mitochondrial turnover must be achieved. Tauroursodeoxycholic acid (TUDCA) is neuroprotective in various neurodegenerative disease models; however, the mechanisms involved are still incompletely characterized. In this study, we investigated the neuroprotective role of TUDCA against mitochondrial damage triggered by the mitochondrial uncoupler carbonyl cyanide m-chlorophelyhydrazone (CCCP). Herein, we show that TUDCA significantly prevents CCCP-induced cell death, ROS generation, and mitochondrial damage. Our results indicate that the neuroprotective role of TUDCA in this cell model is mediated by parkin and depends on mitophagy. The demonstration that pharmacological up-regulation of mitophagy by TUDCA prevents neurodegeneration provides new insights for the use of TUDCA as a modulator of mitochondrial activity and turnover, with implications in neurodegenerative diseases.

Topics: Cell Death; Cell Line, Tumor; Humans; Mitochondria; Mitophagy; Neuroblastoma; Neuroprotective Agents; Reactive Oxygen Species; Taurochenodeoxycholic Acid

Acetaminophen overdose in mice is characterized by hepatocyte endoplasmic reticulum stress, which activates the unfolded protein response, and centrilobular hepatocyte death. We aimed at investigating the therapeutic potential of tauroursodeoxycholic acid, a hydrophilic bile acid known to have anti-apoptotic and endoplasmic reticulum stress-reducing capacities, in experimental acute liver injury induced by acetaminophen overdose.. Mice were injected with 300 mg/kg acetaminophen, 2 hours prior to receiving tauroursodeoxycholic acid, N-acetylcysteine or a combination therapy, and were euthanized 24 hours later. Liver damage was assessed by serum transaminases, liver histology, terminal deoxynucleotidyl transferase dUTP nick end labelling staining, expression profiling of inflammatory, oxidative stress, unfolded protein response, apoptotic and pyroptotic markers.. Acetaminophen overdose resulted in a significant increase in serum transaminases, hepatocyte cell death, unfolded protein response activation, oxidative stress, NLRP3 inflammasome activation, caspase 1 and pro-inflammatory cytokine expressions. Standard of care, N-acetylcysteine and, to a lesser extent, tauroursodeoxycholic treatment were associated with significantly lower transaminase levels, hepatocyte death, unfolded protein response activation, oxidative stress markers, caspase 1 expression and NLRP3 levels. Importantly, the combination of N-acetylcysteine and tauroursodeoxycholic acid improved serum transaminase levels, reduced histopathological liver damage, UPR-activated CHOP, oxidative stress, caspase 1 expression, NLRP3 levels, IL-1β levels and the expression of pro-inflammatory cytokines and this to a greater extend than N-acetylcysteine alone.. These findings indicate that a combination strategy of N-acetylcysteine and tauroursodeoxycholic acid surpasses the standard of care in acetaminophen-induced liver injury in mice and might represent an attractive therapeutic opportunity for acetaminophen-intoxicated patients.

Topics: Acetaminophen; Acetylcysteine; Alanine Transaminase; Animals; Apoptosis; Chemical and Drug Induced Liver Injury; Cytokines; Endoplasmic Reticulum Stress; Hepatocytes; Liver; Male; Mice; Mice, Inbred C57BL; Oxidative Stress; Taurochenodeoxycholic Acid; Unfolded Protein Response

The bile acid conjugate tauroursodeoxycholic acid (TUDCA) is a neuroprotective agent in various animal models of neuropathologies. We have previously shown the anti-inflammatory properties of TUDCA in an animal model of acute neuroinflammation. Here, we present a new anti-inflammatory mechanism of TUDCA through the regulation of transforming growth factor β (TGFβ) pathway. The bacterial lipopolysaccharide (LPS) was injected intravenously (iv) on TGFβ reporter mice (Smad-binding element (SBE)/Tk-Luc) to study in their brains the real-time activation profile of the TGFβ pathway in a non-invasive way. The activation of the TGFβ pathway in the brain of SBE/Tk-Luc mice increased 24 h after LPS injection, compared to control animals. This activation peak increased further in mice treated with both LPS and TUDCA than in mice treated with LPS only. The enhanced TGFβ activation in mice treated with LPS and TUDCA correlated with both an increase in TGFβ3 transcript in mouse brain and an increase in TGFβ3 immunoreactivity in microglia/macrophages, endothelial cells, and neurons. Inhibition of the TGFβ receptor with SB431542 drug reverted the effect of TUDCA on microglia/macrophages activation and on TGFβ3 immunoreactivity. Under inflammatory conditions, treatment with TUDCA enhanced further the activation of TGFβ pathway in mouse brain and increased the expression of TGFβ3. Therefore, the induction of TGFβ3 by TUDCA might act as a positive feedback, increasing the initial activation of the TGFβ pathway by the inflammatory stimulus. Our findings provide proof-of-concept that TGFβ contributes to the anti-inflammatory effect of TUDCA under neuroinflammatory conditions.

Topics: Animals; Anti-Inflammatory Agents; Brain; Disease Models, Animal; Inflammation; Luminescent Measurements; Male; Mice; Mice, Inbred C57BL; Mice, Transgenic; Taurochenodeoxycholic Acid; Transforming Growth Factor beta

Fibroblast growth factor 21 (FGF21) has recently emerged as a novel endocrine hormone involved in the regulation of glucose and lipid metabolism. However, the exact mechanisms whereby FGF21 mediates insulin sensitivity remain not fully understood. In the present study, FGF21was administrated in high-fat diet-induced obese mice and tunicamycin-induced 3T3-L1 adipocytes, and metabolic parameters, endoplasmic reticulum (ER) stress indicators, and insulin signaling molecular were assessed by Western blotting. The administration of FGF21 in obese mice reduced body weight, blood glucose and serum insulin, and increased insulin sensitivity, resulting in alleviation of insulin resistance. Meanwhile, FGF21 treatment reversed suppression of adiponectin expression and restored insulin signaling via inhibiting ER stress in adipose tissue of obese mice. Additionally, suppression of ER stress via the ER stress inhibitor tauroursodeoxycholic acid increased adiponectin expression and improved insulin resistance in obese mice and in tunicamycin-induced adipocytes. In conclusion, our results showed that the administration of FGF21 reversed suppression of adiponectin expression and restored insulin signaling via inhibiting ER stress under the condition of insulin resistance, demonstrating the causative role of ER stress in downregulating adiponectin levels.

Topics: 3T3 Cells; Adipocytes; Adiponectin; Adipose Tissue; Animals; Blood Glucose; Cell Line; Diet, High-Fat; Endoplasmic Reticulum Stress; Fibroblast Growth Factors; Insulin Resistance; Male; Mice; Mice, Inbred C57BL; Mice, Obese; Signal Transduction; Taurochenodeoxycholic Acid; Tunicamycin

Physical activity has profound benefits on health, especially on cardiometabolic wellness. Experiments in rodents with trained exercise have shown that exercise improves vascular function and reduces vascular inflammation by modulating the balance between nitric oxide (NO) and oxidative stress. However, the upstream regulator of exercise-induced vascular benefits is unclear. We aimed to investigate the involvement of peroxisome proliferator-activated receptor δ (PPARδ) in exercise-induced vascular functional improvement. We show that PPARδ is a crucial mediator for exercise to exert a beneficial effect on the vascular endothelium in diabetic mice. In db/db mice and high-fat diet-induced obese mice, 4 weeks of treadmill exercise restored endothelium-dependent vasodilation of aortas and flow-mediated vasodilation in mesenteric resistance arteries, whereas genetic ablation of Ppard abolished such improvements. Exercise induces AMPK activation and subsequent PPARδ activation, which help to reduce endoplasmic reticulum (ER) and oxidative stress, thus increasing NO bioavailability in endothelial cells and vascular tissues. Chemical chaperones 4-phenylbutyric acid and tauroursodeoxycholic acid decrease ER stress and protect against endothelial dysfunction in diabetic mice. The results demonstrate that PPARδ-mediated inhibition of ER stress contributes to the vascular benefits of exercise and provides potentially effective targets for treating diabetic vasculopathy.

Topics: Animals; Aorta; Blood Pressure; Diabetes Mellitus; Diabetic Angiopathies; Diet, High-Fat; Endoplasmic Reticulum Stress; Endothelium, Vascular; Male; Mesenteric Arteries; Mice; Mice, Knockout; Myography; Nitric Oxide; Obesity; Organ Culture Techniques; Oxidative Stress; Phenylbutyrates; Physical Conditioning, Animal; Receptors, Cytoplasmic and Nuclear; Taurochenodeoxycholic Acid; Vasodilation

Bile acids are steroid acids found in the bile of mammals. The bile acid conjugate tauroursodeoxycholic acid (TUDCA) is neuroprotective in different animal models of stroke and neurological diseases. We have previously shown that TUDCA has anti-inflammatory effects on glial cell cultures and in a mouse model of acute neuroinflammation. We show now that microglial cells (central nervous system resident macrophages) express the G protein-coupled bile acid receptor 1/Takeda G protein-coupled receptor 5 (GPBAR1/TGR5) in vivo and in vitro. TUDCA binding to GPBAR1/TGR5 caused an increase in intracellular cAMP levels in microglia that induced anti-inflammatory markers, while reducing pro-inflammatory ones. This anti-inflammatory effect of TUDCA was inhibited by small interference RNA for GPBAR1/TGR5 receptor, as well as by treatment with a protein kinase A (PKA) inhibitor. In the mouse model of acute neuroinflammation, treating the animals with TUDCA was clearly anti-inflammatory. TUDCA biased the microglial phenotype in vivo and in vitro toward the anti-inflammatory. The bile acid receptor GPBAR1/TGR5 could be a new therapeutic target for pathologies coursing with neuroinflammation and microglia activation, such as traumatic brain injuries, stroke, or neurodegenerative diseases. TUDCA and other GPBAR1/TGR5 agonists need to be further investigated, to determine their potential in attenuating the neuropathologies associated with microglia activation. J. Cell. Physiol. 232: 2231-2245, 2017. © 2016 Wiley Periodicals, Inc.

Topics: Animals; Animals, Newborn; Anti-Inflammatory Agents; Cells, Cultured; Cyclic AMP; Cyclic AMP-Dependent Protein Kinases; Disease Models, Animal; Encephalitis; Hippocampus; Inflammation Mediators; Mice, Inbred C57BL; Microglia; Neuroprotective Agents; Prosencephalon; Protein Kinase Inhibitors; Rats, Wistar; Receptors, G-Protein-Coupled; RNA Interference; Signal Transduction; Taurochenodeoxycholic Acid; Time Factors; Transfection

This study explored the effects of Astragalus polysaccharide (APS) on porcine circovirus type 2 (PCV2) infections and its mechanism in vivo and vitro. First, fifty 2-week-old mice were randomly divided into five groups: a group without PCV2 infection and groups with PCV2 infections at 0, 100, 200 or 400 mg/kg APS treatments. The trial lasted for 28 days. The results showed that APS treatments at 200 and 400 mg/kg reduced the pathological injury of tissues, inhibited PCV2 infection and decreased glucose-regulated protein 78 (GRP78) and GADD153/CHOP gene mRNA and protein expression significantly (P < 0.05). Second, a study on endoplasmic reticulum stress mechanism was carried out in PK15 cells. APS treatments at 15 and 45 μg/mL significantly reduced PCV2 infection and GRP78 mRNA and protein expression (P < 0.05). Tunicamycin supplementation increased GRP78 mRNA and protein expression and significantly attenuated the APS-induced inhibition of PCV2 infection (P < 0.05). Tauroursodeoxycholic acid supplementation decreased GRP78 mRNA and protein expression and significantly inhibited PCV2 infection (P < 0.05). In addition, fifty 2-week-old mice were randomly divided into five groups: Con, PCV2, APS + PCV2, TM + PCV2 and TM + APS + PCV2. The results were similar to those in PK15 cells. Taken together, it could be concluded that APS suppresses PCV2 infection by inhibiting endoplasmic reticulum stress.

Topics: Animals; Astragalus Plant; Cell Line; Circoviridae Infections; Circovirus; Endoplasmic Reticulum Chaperone BiP; Endoplasmic Reticulum Stress; Mice; Oxidative Stress; Phytotherapy; Polysaccharides; Swine; Taurochenodeoxycholic Acid; Tunicamycin; Virus Replication

Topics: Angiotensin II; Animals; Aortic Aneurysm; Aortic Aneurysm, Abdominal; Apolipoproteins; Bile; Cell Death; Endoplasmic Reticulum Stress; Mice; Taurochenodeoxycholic Acid

The promising results seen in studies of secondary bile acids in experimental colitis suggest that they may represent an attractive and safe class of drugs for the treatment of inflammatory bowel diseases (IBD). However, the exact mechanism by which bile acid therapy confers protection from colitogenesis is currently unknown. Since the gut microbiota plays a crucial role in the pathogenesis of IBD, and exogenous bile acid administration may affect the community structure of the microbiota, we examined the impact of the secondary bile acid ursodeoxycholic acid (UDCA) and its taurine or glycine conjugates on the fecal microbial community structure during experimental colitis. Daily oral administration of UDCA, tauroursodeoxycholic acid (TUDCA), or glycoursodeoxycholic acid (GUDCA) equally lowered the severity of dextran sodium sulfate-induced colitis in mice, as evidenced by reduced body weight loss, colonic shortening, and expression of inflammatory cytokines. Illumina sequencing demonstrated that bile acid therapy during colitis did not restore fecal bacterial richness and diversity. However, bile acid therapy normalized the colitis-associated increased ratio of

Topics: Animals; Bacteroides; Colon; Dextran Sulfate; Disease Models, Animal; Dysbiosis; Feces; Firmicutes; Gastrointestinal Microbiome; Humans; Inflammatory Bowel Diseases; Mice; Taurine; Taurochenodeoxycholic Acid; Ursodeoxycholic Acid

The role of endoplasmic reticulum stress and the unfolded protein response (UPR) in cholestatic liver disease and fibrosis is not fully unraveled. Tauroursodeoxycholic acid (TUDCA), a hydrophilic bile acid, has been shown to reduce endoplasmic reticulum (ER) stress and counteract apoptosis in different pathologies. We aimed to investigate the therapeutic potential of TUDCA in experimental secondary biliary liver fibrosis in mice, induced by common bile duct ligation. The kinetics of the hepatic UPR and apoptosis during the development of biliary fibrosis was studied by measuring markers at six different timepoints post-surgery by qPCR and Western blot. Next, we investigated the therapeutic potential of TUDCA, 10 mg/kg/day in drinking water, on liver damage (AST/ALT levels) and fibrosis (Sirius red-staining), in both a preventive and therapeutic setting. Common bile duct ligation resulted in the increased protein expression of CCAAT/enhancer-binding protein homologous protein (CHOP) at all timepoints, along with upregulation of pro-apoptotic caspase 3 and 12, tumor necrosis factor receptor superfamily, member 1A (TNFRsf1a) and Fas-Associated protein with Death Domain (FADD) expression. Treatment with TUDCA led to a significant reduction of liver fibrosis, accompanied by a slight reduction of liver damage, decreased hepatic protein expression of CHOP and reduced gene and protein expression of pro-apoptotic markers. These data indicate that TUDCA exerts a beneficial effect on liver fibrosis in a model of cholestatic liver disease, and suggest that this effect might, at least in part, be attributed to decreased hepatic UPR signaling and apoptotic cell death.

Topics: Animals; Apoptosis; Biliary Tract; Biliary Tract Diseases; Blotting, Western; Caspase 12; Caspase 3; Cholagogues and Choleretics; Cholestasis; Disease Models, Animal; Fibrosis; Gene Expression; Liver; Liver Cirrhosis; Male; Mice; Reverse Transcriptase Polymerase Chain Reaction; Taurochenodeoxycholic Acid; Transcription Factor CHOP; Tumor Necrosis Factor-alpha; Unfolded Protein Response

HSP70-HSP90 organizing protein (HOP) is a well-studied family of cytosolic cochaperones. However, the possible role of HOP during the endoplasmic reticulum (ER) stress response and the identity of its interactors within the ER were not previously addressed in any eukaryote. We have demonstrated that Arabidopsis HOP3, whose function was not studied before, interacts in vivo with cytosolic HSP90 and HSP70, and, unexpectedly, with binding immunoglobulin protein (BiP), a HSP70 ER-resident protein. Although BiP lacks the domain described in other eukaryotes for HOP-HSP70 binding, it interacts with HOP3 through a non-canonical association to its nucleotide binding domain. Consistent with this interaction with BiP, HOP3 is partially localized at the ER. Moreover, HOP3 is induced both at transcript and protein levels by unfolded protein response (UPR) inducer agents by a mechanism dependent on inositol-requiring enzyme 1 (IRE1). Importantly, hop3 loss-of-function mutants show a reduction in pollen germination and a hypersensitive phenotype in the presence of ER stress inducer agents, a phenotype that is reverted by the addition of the chemical chaperone tauroursodeoxycholic acid (TUDCA). All these data demonstrate, for the first time in any eukaryote, a main role of HOP as an important regulator of the ER stress response, a process intimately linked in plants to important specific developmental programs and to environmental stress sensing and response.

Topics: Arabidopsis; Arabidopsis Proteins; Carrier Proteins; Dithiothreitol; Endoplasmic Reticulum; Endoplasmic Reticulum Stress; Gene Expression Regulation, Plant; HSP70 Heat-Shock Proteins; HSP90 Heat-Shock Proteins; Molecular Chaperones; Multigene Family; Mutation; Phenotype; Protein Binding; Protein Domains; RNA, Messenger; Subcellular Fractions; Taurochenodeoxycholic Acid; Tunicamycin; Unfolded Protein Response

Bile acids regulate the expression of intestinal bile acid transporters and are natural ligands for nuclear receptors controlling inflammation. Accumulating evidence suggests that signaling through these receptors is impaired in inflammatory bowel disease. We investigated whether tauroursodeoxycholic acid (TUDCA), a secondary bile acid with cytoprotective properties, regulates ileal nuclear receptor and bile acid transporter expression and assessed its therapeutic potential in an experimental model of Crohn's disease (CD). Gene expression of the nuclear receptors farnesoid X receptor, pregnane X receptor and vitamin D receptor and the bile acid transporters apical sodium-dependent bile acid transporter and organic solute transporter α and β was analyzed in Caco-2 cell monolayers exposed to tumor necrosis factor (TNF)α, in ileal tissue of TNF

Topics: Adult; Animals; Bile Acids and Salts; Caco-2 Cells; Carrier Proteins; Crohn Disease; Disease Models, Animal; Down-Regulation; Female; Homeostasis; Humans; Ileitis; Ileum; Male; Membrane Glycoproteins; Mice; Mice, Transgenic; Receptors, Cytoplasmic and Nuclear; Taurochenodeoxycholic Acid; Young Adult

Quercetin (3,3',4',5,7-pentahydroxyflavone, Qu) is a promising cancer chemo-preventive agent for various cancers because it inhibits disease progression and promotes apoptotic cell death. In our previous study, we demonstrated that Qu could evoke ER stress to enhance drug cytotoxicity in ovarian cancer (OC). However, Qu-induced ER stress in OC is still poorly understood. Here, we demonstrated that Qu evoked ER stress to involve in mitochondria apoptosis pathway via the p-STAT3/Bcl-2 axis in OC cell lines and in primary OC cells. Unexpectedly, inhibition of ER stress did not reverse Qu-induced cell death. Further functional studies revealed that Qu-induced ER stress could activate protective autophagy concomitantly by activating the p-STAT3/Bcl-2 axis in this process. Moreover, the autophagy scavenger 3-MA was shown to enhance Qu's anticancer effects in an ovarian cancer mice xenograft model. These findings revealed a novel role of ER stress as a "double edge sword" participating in Qu-induced apoptosis of OC and might provide a new angle to consider in clinical studies of biological modifiers that may circumvent drug resistance in patients by targeting protective autophagy pathways.

Topics: Adenine; Animals; Antineoplastic Agents, Phytogenic; Apoptosis; Autophagy; Cell Line, Tumor; Endoplasmic Reticulum Stress; Female; Humans; Mice; Mice, Inbred NOD; Mice, Nude; Mice, SCID; Neoplasm Proteins; Ovarian Neoplasms; Quercetin; Random Allocation; RNA, Small Interfering; Signal Transduction; Specific Pathogen-Free Organisms; STAT3 Transcription Factor; Taurochenodeoxycholic Acid; Tumor Stem Cell Assay; Xenograft Model Antitumor Assays

Despite substantial advances in the research exploring the pathogenesis of Type 1 Diabetes (T1D), the pathophysiological mechanisms involved remain unknown. We hypothesized in this study that interferon alpha (IFNα) participates in the early stages of T1D development by triggering endoplasmic reticulum (ER) stress. To verify our hypothesis, human islets and human EndoC-βH1 cells were exposed to IFNα and tested for ER stress markers, glucose stimulated insulin secretion (GSIS) and insulin content. IFNα treatment induced upregulation of ER stress markers including Binding immunoglobulin Protein, phospho-eukaryotic translation initiation factor 2α, spliced- X-box binding protein-1, C/EBP homologous protein and activating transcription factor 4. Intriguingly, IFNα treatment did not impair GSIS but significantly decreased insulin production in both human islets and EndoC-βH1 cells. Furthermore, IFNα decreased the expression of both proinsulin convertase 1 and proinsulin convertase 2, suggesting an altered functional state of the beta cells characterized by a slower proinsulin-insulin conversion. Pretreatment of both human islets and EndoC-βH1 cells with chemical chaperones 4-phenylbutyric acid and tauroursodeoxycholic acid completely prevented IFNα effects, indicating an ER stress-mediated impairment of insulin production. We demonstrated for the first time that IFNα elicits ER stress in human beta cells providing a novel mechanistic role for this virus-induced cytokine in the development of T1D. Compounds targeting molecular processes altered in ER-stressed beta cells could represent a potential therapeutic strategy to prevent IFNα-induced beta cell dysfunction in the early onset of T1D.

Topics: Apoptosis; Cells, Cultured; Cytokines; Diabetes Mellitus, Type 1; Endoplasmic Reticulum Stress; Humans; Insulin; Insulin-Secreting Cells; Interferon-alpha; Phenylbutyrates; Proprotein Convertase 1; Proprotein Convertase 2; Taurochenodeoxycholic Acid; Transcription Factor CHOP; X-Box Binding Protein 1

The present study investigated the effects of tauroursodeoxycholic acid (TUDCA) on the lipolytic action of tumor necrosis factor (TNF)-α in 3T3-L1 adipocytes. Following treatment with TNF‑α, cell viability was determined by MTT assay to select the optimum concentration and duration of TNF‑α treatment in 3T3‑L1 adipocytes. Intracellular lipid droplet dispersion and glycerin content in culture media were determined to evaluate the effect of TUDCA on TNF‑α‑induced lipolysis in 3T3‑L1 adipocytes. Western blotting was performed to detect protein expression levels of perilipin‑A and protein markers of endoplasmic reticulum stress: Immunoglobulin‑binding protein (BiP), inositol‑requiring enzyme (IRE), c‑Jun N‑terminal kinase (JNK), phosphorylated (p)‑IRE and p‑JNK. Following treatment with 50 ng/ml TNF‑α for 24 h, glycerin content increased significantly and lipid droplets were dispersed. Glycerin content was reduced significantly and dispersal of lipid droplets reduced following pretreatment of 3T3‑L1 adipocytes with 1 mmol/l TUDCA. TNF‑α additionally activated the expression of BiP, p‑IRE and p‑JNK in a time‑dependent manner; following pretreatment of 3T3‑L1 adipocytes with 1 mmol/l TUDCA, the expression levels of these three proteins decreased. Therefore, TUDCA may inhibit TNF-α-induced lipolysis in 3T3‑L1 adipocytes and reduce production of free fatty acids. Its underlying molecular mechanisms are potentially associated with the inhibition of activation of the IRE‑JNK signaling pathway, which influences perilipin-A expression levels.

Topics: 3T3-L1 Cells; Adipocytes; Animals; Biomarkers; Cell Survival; Endoplasmic Reticulum Stress; Endoribonucleases; JNK Mitogen-Activated Protein Kinases; Lipid Droplets; Lipolysis; Mice; Perilipin-1; Protein Serine-Threonine Kinases; Signal Transduction; Taurochenodeoxycholic Acid; Time Factors; Tumor Necrosis Factor-alpha

Newly translated proteins must undergo proper folding to ensure their function. To enter a low energy state, misfolded proteins form aggregates, which are associated with many degenerative diseases, such as Huntington's disease and chronic kidney disease (CKD). Recent studies have shown the use of low molecular weight chemical chaperones to be an effective method of reducing protein aggregation in various cell types. This study demonstrates a novel non-biased assay to assess the molecular efficacy of these compounds at preventing protein misfolding and/or aggregation. This assay utilizes a thioflavin T fluorescent stain to provide a qualitative and quantitative measure of protein misfolding within cells. The functionality of this method was first assessed in renal proximal tubule epithelial cells treated with various endoplasmic reticulum (ER) stress inducers. Once established in the renal model system, we analyzed the ability of some known chemical chaperones to reduce ER stress. A total of five different compounds were selected: 4-phenylbutyrate (4-PBA), docosahexaenoic acid (DHA), tauroursodeoxycholic acid, trehalose, and glycerol. The dose-dependent effects of these compounds at reducing thapsigargin-induced ER stress was then analyzed, and used to determine their EC

Topics: Benzothiazoles; Cell Line; Docosahexaenoic Acids; Endoplasmic Reticulum Stress; Epithelial Cells; Glycerol; Humans; Kidney Tubules, Proximal; Molecular Weight; Phenylbutyrates; Protein Aggregates; Protein Aggregation, Pathological; Protein Folding; Staining and Labeling; Taurochenodeoxycholic Acid; Thapsigargin; Thiazoles; Trehalose; Unfolded Protein Response; Xenobiotics

To study the time-course relationship between vascular functions and endoplasmic reticulum (ER) stress in type 2 diabetes, we investigated vascular function and associated protein expression, including cyclo-oxygenase (COX), ER stress, and apoptotic markers, in renal arteries (RA) from type 2 diabetic Otsuka Long-Evans Tokushima fatty (OLETF) rats at the young adult (4 months old) and aged (18 months old) stages. In the RA of aged OLETF (vs. young OLETF), we found: (1) Increased contractions induced by uridine adenosine tetraphosphate (Up4A) and phenylephrine, (2) decreased relaxation and increased contraction induced by acetylcholine (ACh) at lower and higher concentrations, respectively, and (3) increased expression of COX-1 and C/EBP-homologous protein (CHOP, a pro-apoptotic protein). In aged rats, the expression of COX-1, COX-2, PDI (an ER protein disulfide isomerase), Bax (a proapoptotic marker), and CHOP were increased in RA from OLETF rats (vs. age-matched control Long-Evans Tokushima Otsuka [LETO] rats). Up-regulation of PDI and Bax were seen in the RA from young OLETF (vs. young LETO) rats. No age-related alterations were apparent in the above changes in RA from LETO rats, excluding ACh-induced contraction. Short-term treatment with the ER stress inhibitor tauroursodeoxycholic acid (TUDCA, 100 mg/kg per day, intraperitoneally for 1 week) to OLETF rats at the chronic stage of the disease (12 months old) could suppress renal arterial contractions induced by Up4A and ACh. These results suggest that a long-term duration of disease may be important for the development of vascular dysfunction rather than aging per se. The early regulation of ER stress may be important against the development of diabetes-associated vascular dysfunction.

Topics: Acetylcholine; Aging; Animals; bcl-2-Associated X Protein; Biomarkers; Diabetes Mellitus, Type 2; Dinucleoside Phosphates; Endoplasmic Reticulum Stress; Endothelium, Vascular; Group IV Phospholipases A2; Male; Nitroprusside; Phenylephrine; Prostaglandin-Endoperoxide Synthases; Rats; Rats, Inbred OLETF; Renal Artery; Sirtuin 1; Taurochenodeoxycholic Acid; Vasodilation

Alternations of copper (Cu) and zinc (Zn) status in diabetes have received a great attention. Tauroursodeoxycholic acid (TUDCA) and 4-phenylbutyric acid (PBA) could alleviate the increased endoplasmic reticulum (ER) stress and prevent insulin resistance. This study aimed to investigate the effect of TUDCA and PBA on metabolism of Cu and Zn in diabetic mice model. Diabetes was induced by streptozotocin in FVB mice treated with and without TUDCA and PBA. Determination of Cu and Zn in tissues and serum by acid digestion was followed by ICP-MS. The renal and serum Cu levels were significantly higher, while the hepatic Cu and Zn levels were significantly decreased in the diabetic mice at 2 weeks and 2 months after diabetes onset. The increase of cardiac Cu together with the decrease of muscular Zn was found in the diabetic mice only at 2 months. Cu levels were positively correlated with Zn in the heart, liver, kidney, muscle, spleen, and serum of diabetic and control mice at both 2 weeks and 2 months. Both PBA and TUDCA reduced serum Zn, and PBA reduced hepatic Cu to normal levels in the diabetic mice at two time points, while PBA normalized serum Cu in the diabetic mice only at 2 months. PBA increased hepatic Zn to normal levels in the diabetic mice at 2 weeks, while it partially increased hepatic Zn in the same group at 2 months. Therefore, maintaining homeostasis of Cu and Zn by TUDCA and PBA in diabetes needs to be received with special attention.

Topics: Animals; Copper; Diabetes Mellitus, Experimental; Diabetes Mellitus, Type 1; Liver; Mice; Phenylbutyrates; Taurochenodeoxycholic Acid; Zinc

We explored the potential protective effects of tauroursodeoxycholic acid (TUDCA) on cone photoreceptor survival in a model of rapid retinal degeneration, the ß-Pde6 (rd1) (rd1) mouse model. We injected two strains of rd1 mice (B6.C3-Pde6b (rd1) Hps4(le)/J and C57BL/6J-Pde6b (rd1-2)/J mice) daily from postnatal day (P) 6 to P21 with TUDCA or vehicle. At P21, retinal function was evaluated with light-adapted electroretinography (ERG) and retinal structure was observed with plastic or frozen sections. TUDCA treatment partially preserved function and structure in B6.C3-Pde6b (rd1) Hps4(le)/J mice but only partially preserved structure in C57BL/6J-Pde6b (rd1-2)/J mice. Our results suggest a possible intervention for patients undergoing rapid retinal degeneration.

Topics: Animals; Cell Count; Disease Models, Animal; Electroretinography; Humans; Mice; Mice, Inbred C57BL; Mice, Mutant Strains; Photoreceptor Cells, Vertebrate; Protective Agents; Retina; Retinitis Pigmentosa; Species Specificity; Taurochenodeoxycholic Acid

It is known that osteogenic differentiation of mesenchymal stem cells (MSCs) can be promoted by suppression of adipogenesis of MSCs. We have recently found that the chemical chaperone tauroursodeoxycholic acid (TUDCA) significantly reduces adipogenesis of MSCs. In the present study, we examined whether TUDCA can promote osteogenic differentiation of bone marrow-derived mesenchymal stem cells (BMMSCs) by regulating Integrin 5 (ITGA5) associated with activation of ERK1/2 signal pathway and thereby enhance bone tissue regeneration by reducing apoptosis and the inflammatory response. TUDCA treatment promoted in vitro osteogenic differentiation of BMMSCs and in vivo bone tissue regeneration in a calvarial defect model, as confirmed by micro-computed tomography, histological staining, and immunohistochemistry for osteocalcin. In addition, TUDCA treatment significantly decreased apoptosis and the inflammatory response in vivo and in vitro, which is important to enhance bone tissue regeneration. These results indicate that TUDCA plays a critical role in enhancing osteogenesis of BMMSCs, and is therefore a potential alternative drug for bone tissue regeneration.

Topics: Animals; Apoptosis; Bone Marrow Cells; Bone Regeneration; Cell Differentiation; Inflammation; Male; MAP Kinase Signaling System; Mesenchymal Stem Cells; Mice, Inbred BALB C; Osteogenesis; Skull; Taurochenodeoxycholic Acid; X-Ray Microtomography

Endoplasmic reticulum stress is defined as the accumulation of unfolded proteins in the endoplasmic reticulum, and is caused by conditions such as heat or agents that cause endoplasmic reticulum stress, including tunicamycin and dithiothreitol. Autophagy, a major pathway for degradation of macromolecules in the vacuole, is activated by these stress agents in a manner dependent on inositol-requiring enzyme 1b (IRE1b), and delivers endoplasmic reticulum fragments to the vacuole for degradation. In this study, we examined the mechanism for activation of autophagy during endoplasmic reticulum stress in Arabidopsis thaliana. The chemical chaperones sodium 4-phenylbutyrate and tauroursodeoxycholic acid were found to reduce tunicamycin- or dithiothreitol-induced autophagy, but not autophagy caused by unrelated stresses. Similarly, over-expression of BINDING IMMUNOGLOBULIN PROTEIN (BIP), encoding a heat shock protein 70 (HSP70) molecular chaperone, reduced autophagy. Autophagy activated by heat stress was also found to be partially dependent on IRE1b and to be inhibited by sodium 4-phenylbutyrate, suggesting that heat-induced autophagy is due to accumulation of unfolded proteins in the endoplasmic reticulum. Expression in Arabidopsis of the misfolded protein mimics zeolin or a mutated form of carboxypeptidase Y (CPY*) also induced autophagy in an IRE1b-dependent manner. Moreover, zeolin and CPY* partially co-localized with the autophagic body marker GFP-ATG8e, indicating delivery to the vacuole by autophagy. We conclude that accumulation of unfolded proteins in the endoplasmic reticulum is a trigger for autophagy under conditions that cause endoplasmic reticulum stress.

Topics: Arabidopsis; Autophagy; Dithiothreitol; Endoplasmic Reticulum; Endoplasmic Reticulum Stress; Phenylbutyrates; Protein Unfolding; Taurochenodeoxycholic Acid; Tunicamycin; Vacuoles

Sensorineural hearing loss has long been the subject of experimental and clinical research for many years. The recently identified novel mutation of the Cadherin23 (Cdh23) gene, Cdh23(erl/erl), was proven to be a mouse model of human autosomal recessive nonsyndromic deafness (DFNB12). Tauroursodeoxycholic acid (TUDCA), a taurine-conjugated bile acid, has been used in experimental research and clinical applications related to liver disease, diabetes, neurodegenerative diseases, and other diseases associated with apoptosis. Because hair cell apoptosis was implied to be the cellular mechanism leading to hearing loss in Cdh23(erl/erl) mice (erl mice), this study investigated TUDCA's otoprotective effects in erl mice: preventing hearing impairment and protecting against hair cell death. Our results showed that systemic treatment with TUDCA significantly alleviated hearing loss and suppressed hair cell death in erl mice. Additionally, TUDCA inhibited apoptotic genes and caspase-3 activation in erl mouse cochleae. The data suggest that TUDCA could be a potential therapeutic agent for human DFNB12.

Topics: Analysis of Variance; Animals; Cadherins; Caspases; Cell Count; Cell Death; Cholagogues and Choleretics; Disease Models, Animal; Evoked Potentials, Auditory, Brain Stem; Hair Cells, Auditory; Hearing Loss; In Situ Nick-End Labeling; Mice; Mice, Transgenic; Mutation; Otoacoustic Emissions, Spontaneous; RNA, Messenger; Taurochenodeoxycholic Acid

Uremic cardiomyopathy (UCM) is a complication in chronic kidney disease. We investigated if endoplasmic reticulum stress (ERS) is involved in UCM, and determined the efficacy of tauroursodeoxycholic acid (TUDCA) in UCM prevention.. Mice were divided randomly into three groups: sham (saline, i.p), 5/6 nephrectomized (Nx) (saline, i.p) and Nx+TUDCA (250 mg/kg/day, i.p.). Renal function was assessed by measuring serum creatinine, blood urea nitrogen and by periodic acid-Schiff reagent staining. Histologic examination of cardiac fibrosis and apoptosis was determined by Masson's trichrome and TUNEL assay. Cardiac function was evaluated by echocardiography. Fibrotic factors (transforming growth factor-β, fibronectin, collagen I/IV) were evaluated by real-time PCR. ERS-related proteins were measured by western blotting.. Impaired renal function and cardiac dysfunction were shown in 5/6 nephrectomy mice but were improved significantly by TUDCA. 5/6 nephrectomy mice exhibited marked cardiomyocyte apoptosis, cardiac fibrosis and elevated pro-fibrotic factors. ERS markers (GRP78, GRP94, P-PERK, P-eIF2a) and ERS-induced apoptosis pathways (activation of CHOP and caspase-12) were increased significantly in 5/6 nephrectomy mice, and TUDCA treatment blunted these changes.. ERS has a key role in UCM, and the cardioprotective role of TUDCA is related to inhibition of ERS-induced apoptosis by inhibition of CHOP and caspase-12 pathways.

Topics: Animals; Apoptosis; Blood Urea Nitrogen; Cardiomyopathies; Collagen Type I; Creatinine; Echocardiography; Endoplasmic Reticulum Chaperone BiP; Endoplasmic Reticulum Stress; Fibronectins; Heart; Heat-Shock Proteins; HSP70 Heat-Shock Proteins; Kidney; Male; Membrane Proteins; Mice; Mice, Inbred C57BL; Myocardium; Protective Agents; Taurochenodeoxycholic Acid; Transforming Growth Factor beta

Nicotine exposure during pregnancy leads to placental insufficiency impairing both fetal and neonatal development. Previous studies from our laboratory have demonstrated that in rats, nicotine augmented endoplasmic reticulum (ER) stress in association with placental insufficiency; however, the underlying mechanisms remain elusive. Therefore, we sought to investigate the possible direct effect of nicotine on ER stress in Rcho-1 rat placental trophoblast giant (TG) cells during differentiation. Protein and/or mRNA expression of markers involved in ER stress (eg, phosphorylated PERK, eIF2α, CHOP, and BiP/GRP78) and TG cell differentiation and function (eg, Pl-1, placental growth factor [Pgf], Hsd11b1, and Hsd11b2) were quantified via Western blot or real-time polymerase chain reaction. Nicotine treatment led to dose-dependent increases in the phosphorylation of PERK[Thr981] and eIF2α[Ser51], whereas pretreatment with a nicotinic acetylcholine receptor (nAChR) antagonist (mecamylamine hydrochloride) blocked the induction of PERK phosphorylation, verifying the direct involvement of nicotine and nAChR binding. We next investigated select target genes known to play essential roles in placental TG cell differentiation and function (Pl-1, Pgf, Hsd11b1, and Hsd11b2), and found that nicotine significantly augmented the mRNA levels of Hsd11b1 in a dose-dependent manner. Furthermore, using tauroursodeoxycholic acid, a safe bile acid known to improve protein chaperoning and folding, we were able to prevent nicotine-induced increases in both PERK phosphorylation and Hsd11b1 mRNA levels, revealing a potential novel therapeutic approach to reverse the deleterious effects of nicotine exposure in pregnancy. Collectively, these results implicate that nicotine, acting through its receptor, can directly augment ER stress and impair placental function.

Topics: 11-beta-Hydroxysteroid Dehydrogenase Type 1; Animals; Cell Line; Dose-Response Relationship, Drug; eIF-2 Kinase; Endoplasmic Reticulum Stress; Female; Gene Expression Regulation; Giant Cells; Mecamylamine; Nicotine; Nicotinic Agonists; Nicotinic Antagonists; Phosphorylation; Rats; Receptors, Nicotinic; RNA, Messenger; Signal Transduction; Taurochenodeoxycholic Acid; Time Factors; Trophoblasts

Bronchopulmonary dysplasia (BPD), a chronic lung disease of prematurity, has been linked to endoplasmic reticulum (ER) stress. To investigate a causal role for ER stress in BPD pathogenesis, we generated conditional knockout (KO) mice (cGrp78(f/f)) with lung epithelial cell-specific KO of Grp78, a gene encoding the ER chaperone 78-kD glucose-regulated protein (GRP78), a master regulator of ER homeostasis and the unfolded protein response (UPR). Lung epithelial-specific Grp78 KO disrupted lung morphogenesis, causing developmental arrest, increased alveolar epithelial type II cell apoptosis, and decreased surfactant protein and type I cell marker expression in perinatal lungs. cGrp78(f/f) pups died immediately after birth, likely owing to respiratory distress. Importantly, Grp78 KO triggered UPR activation with marked induction of the proapoptotic transcription factor CCAAT/enhancer-binding proteins (C/EBP) homologous protein (CHOP). Increased expression of genes involved in oxidative stress and cell death and decreased expression of genes encoding antioxidant enzymes suggest a role for oxidative stress in alveolar epithelial cell (AEC) apoptosis. Increased Smad3 phosphorylation and expression of transforming growth factor-β/Smad3 targets Cdkn1a (encoding p21) and Gadd45a suggest that interactions among the apoptotic arm of the UPR, oxidative stress, and transforming growth factor-β/Smad signaling pathways contribute to Grp78 KO-induced AEC apoptosis and developmental arrest. Chemical chaperone Tauroursodeoxycholic acid reduced UPR activation and apoptosis in cGrp78(f/f) lungs cultured ex vivo, confirming a role for ER stress in observed AEC abnormalities. These results demonstrate a key role for GRP78 in AEC survival and gene expression during lung development through modulation of ER stress, and suggest the UPR as a potential therapeutic target in BPD.

Topics: Alveolar Epithelial Cells; Animals; Apoptosis; Biomarkers; Cell Differentiation; Cell Survival; Cells, Cultured; Endoplasmic Reticulum; Endoplasmic Reticulum Chaperone BiP; Endoplasmic Reticulum Stress; Heat-Shock Proteins; Homeostasis; Mice, Knockout; Oligonucleotide Array Sequence Analysis; Oxidative Stress; RNA, Messenger; Taurochenodeoxycholic Acid; Unfolded Protein Response

The bile acids (BAs) and their conjugates have vascular activities and the serum levels of BAs and their conjugates are increased in liver diseases. In the present study, we examined the in vitro vasoactivities of BAs conjugates taurochenodeoxycholate (TCDC) (5-80 µM), glycochenodeoxycholate (GCDC) (20-150 µM) and tauroursodeoxycholate (TUDC) (20-150 µM) in rat mesenteric arteries and thoracic aorta. The isometric tension of rat mesenteric arteries and thoracic aorta was recorded by using multi-wire myograph systems. TCDC induced significant concentration-dependent relaxation in endothelium-intact but not endothelium-denuded rat mesenteric arteries pre-contracted with phenylephrine (PE). TCDC also showed vasorelaxant effects on high K(+) induced contraction in rat mesenteric arteries. L-NAME treatment inhibited TCDC-induced relaxation in mesenteric arteries pre-contracted with PE. Acute treatment with TCDC increased protein expression of P-eNOS (ser1177) in human umbilical vein endothelial cells. GCDC dose-dependently relaxed PE-induced vasoconstriction in both endotheium-intact and endothelium-denuded rat mesenteric arteries, but GCDC showed no effect on high K(+)-induced vasoconstriction. Both GCDC and TCDC showed no apparent relaxation on PE and high K(+)-induced vasoconstriction in rat thoracic aorta. TUDC showed no effect on PE and high K(+)-induced vasoconstriction in rat mesenteric arteries and thoracic aorta. The study demonstrates that TCDC relaxes rat mesenteric arteries through activating eNOS. TCDC might be the major BAs conjugate for vasorelaxation in vivo.

Topics: Animals; Aorta, Thoracic; Dose-Response Relationship, Drug; Endothelium, Vascular; Enzyme Activation; Glycochenodeoxycholic Acid; Humans; Male; Mesenteric Arteries; Nitric Oxide Synthase Type III; Rats; Rats, Sprague-Dawley; Taurochenodeoxycholic Acid; Vasodilation

While bile acids are important for the digestion process, they also act as signaling molecules in many tissues, including the endocrine pancreas, which expresses specific bile acid receptors that regulate several cell functions. In this study, we investigated the effects of the conjugated bile acid TUDCA on glucose-stimulated insulin secretion (GSIS) from pancreatic β-cells.. Pancreatic islets were isolated from 90-day-old male mice. Insulin secretion was measured by radioimmunoassay, protein phosphorylation by western blot, Ca(2+) signals by fluorescence microscopy and ATP-dependent K(+) (KATP) channels by electrophysiology.. TUDCA dose-dependently increased GSIS in fresh islets at stimulatory glucose concentrations but remained without effect at low glucose levels. This effect was not associated with changes in glucose metabolism, Ca(2+) signals or KATP channel activity; however, it was lost in the presence of a cAMP competitor or a PKA inhibitor. Additionally, PKA and CREB phosphorylation were observed after 1-hour incubation with TUDCA. The potentiation of GSIS was blunted by the Gα stimulatory, G protein subunit-specific inhibitor NF449 and mimicked by the specific TGR5 agonist INT-777, pointing to the involvement of the bile acid G protein-coupled receptor TGR5.. Our data indicate that TUDCA potentiates GSIS through the cAMP/PKA pathway.

Topics: Animals; Calcium Signaling; Cyclic AMP; Cyclic AMP Response Element-Binding Protein; Cyclic AMP-Dependent Protein Kinases; Dose-Response Relationship, Drug; Glucose; In Vitro Techniques; Insulin; Insulin-Secreting Cells; KATP Channels; Male; Mice; Mice, Inbred C57BL; Phosphorylation; Protein Kinase Inhibitors; Receptors, G-Protein-Coupled; Signal Transduction; Taurochenodeoxycholic Acid

Tauroursodeoxycholic acid (TUDCA), one of the main ingredients from bear gall which hold "Clearing heat and detoxification, Removing liver fire for improving eyesight" functions, is formed by the conjugation of ursodeoxycholic acid (UDCA) with taurine. However, the limited information of TUDCA on protecting diabetic retinopathy (DR) has been known. The present study was conducted to evaluate the protection of TUDCA on high glucose-induced human retinal microvascular endothelial cells (HRMECs) dysfunction and streptozotocin (STZ)-induced diabetic retinopathy (DR) rats and the possible mechanism underlying was also explored.. The proliferation of high glucose-induced HRMECs was determined by MTT assay. DR rats' model was established by an administration of high-glucose-fat diet and an intraperitoneal injection of STZ (30mg/kg). The cell supernatant and rats' serum were collected for the assays of NO content by ELISA kits. Retinas were stained with hematoxylin and eosin (HE) to observe pathological changes. Immunohistochemical assay was applied to examine the protein expression of ICAM-1, NOS, NF-κB p65 and VEGF in rat retinas. Furthermore, western blot analysis was carried out to examine the protein expression of ICAM-1, NOS, NF-κB p65 and VEGF in high glucose-induced HRMECs.. After treating with TUDCA, high glucose-induced HRMECs proliferation could be significantly inhibited. TUDCA (5.0μM, 25.0μM and 125.0μM) could decrease NO content in high glucose-induced HRMECs. Furthermore, TUDCA (500mg/kg/d and 250mg/kg/d) also decrease NO content in serum of DR rats. Additionally, both immunocytochemistry analysis and western blot analysis showed that the over-expression of ICAM-1, NOS, NF-κB p65 and VEGF were significantly decreased by TUDCA.. The data indicated that TUDCA could ameliorate DR by decreasing NO content and down-regulating the protein expression of ICAM-1, NOS, NF-κB p65 and VEGF. Thus, our experimental results suggested that TUDCA might be a potential drug for the prevention and treatment of DR.

Topics: Animals; Diabetes Mellitus, Experimental; Diabetic Retinopathy; Endothelial Cells; Gene Expression Regulation, Enzymologic; Glucose; Humans; Intercellular Adhesion Molecule-1; Male; Mice; Nitric Oxide Synthase; Rats; Rats, Sprague-Dawley; Retinal Vessels; Taurochenodeoxycholic Acid; Transcription Factor RelA

Endoplasmic reticulum (ER) stress is a major contributor to inflammatory diseases, such as Crohn disease and type 2 diabetes. ER stress induces the unfolded protein response, which involves activation of three transmembrane receptors, ATF6, PERK and IRE1α. Once activated, IRE1α recruits TRAF2 to the ER membrane to initiate inflammatory responses via the NF-κB pathway. Inflammation is commonly triggered when pattern recognition receptors (PRRs), such as Toll-like receptors or nucleotide-binding oligomerization domain (NOD)-like receptors, detect tissue damage or microbial infection. However, it is not clear which PRRs have a major role in inducing inflammation during ER stress. Here we show that NOD1 and NOD2, two members of the NOD-like receptor family of PRRs, are important mediators of ER-stress-induced inflammation in mouse and human cells. The ER stress inducers thapsigargin and dithiothreitol trigger production of the pro-inflammatory cytokine IL-6 in a NOD1/2-dependent fashion. Inflammation and IL-6 production triggered by infection with Brucella abortus, which induces ER stress by injecting the type IV secretion system effector protein VceC into host cells, is TRAF2, NOD1/2 and RIP2-dependent and can be reduced by treatment with the ER stress inhibitor tauroursodeoxycholate or an IRE1α kinase inhibitor. The association of NOD1 and NOD2 with pro-inflammatory responses induced by the IRE1α/TRAF2 signalling pathway provides a novel link between innate immunity and ER-stress-induced inflammation.

Topics: Animals; Bacterial Outer Membrane Proteins; Brucella abortus; Cell Line; Dithiothreitol; Endoplasmic Reticulum; Endoplasmic Reticulum Stress; Endoribonucleases; Female; Humans; Immunity, Innate; Inflammation; Interleukin-6; Male; Mice; Mice, Inbred C57BL; NF-kappa B; Nod1 Signaling Adaptor Protein; Nod2 Signaling Adaptor Protein; Protein Serine-Threonine Kinases; Receptors, Pattern Recognition; Signal Transduction; Taurochenodeoxycholic Acid; Thapsigargin; TNF Receptor-Associated Factor 2; Unfolded Protein Response

Vascular endothelial growth factor A (VEGFA) is crucial for ovarian angiogenesis, but its excess production induces ovarian hyperstimulation syndrome (OHSS). The aim of this study was to determine whether endoplasmic reticulum (ER) stress regulates VEGFA expression in granulosa cells, and whether its activation is involved in OHSS development. The expression of the spliced form of X-box-binding protein 1 [XBP1(S)], induced by ER stress, in cumulus cells from OHSS patients was higher than that in cumulus cells from non-OHSS patients. The ER stress inducer tunicamycin increased human chorionic gonadotropin-induced VEGFA production in human granulosa cells through the induction of XBP1(S), and pretreatment with the ER stress inhibitor tauroursodeoxycholic acid (TUDCA) abrogated the effect of tunicamycin. In OHSS model rats, TUDCA administration prevented the OHSS development, reducing ovarian VEGFA production. Our findings suggest ER stress upregulates hCG-induced VEGFA production in granulosa cells, indicating that ER stress might be involved in OHSS development.

Topics: Adult; Animals; Capillary Permeability; Chorionic Gonadotropin; Cumulus Cells; Disease Models, Animal; Endoplasmic Reticulum Stress; Female; Humans; Luteal Cells; Ovarian Hyperstimulation Syndrome; Rats; RNA, Messenger; Taurochenodeoxycholic Acid; Tunicamycin; Up-Regulation; Vascular Endothelial Growth Factor A; X-Box Binding Protein 1

Autotaxin (ATX) generates the lipid mediator lysophosphatidic acid (LPA). ATX-LPA signalling is involved in multiple biological and pathophysiological processes, including vasculogenesis, fibrosis, cholestatic pruritus and tumour progression. ATX has a tripartite active site, combining a hydrophilic groove, a hydrophobic lipid-binding pocket and a tunnel of unclear function. We present crystal structures of rat ATX bound to 7α-hydroxycholesterol and the bile salt tauroursodeoxycholate (TUDCA), showing how the tunnel selectively binds steroids. A structure of ATX simultaneously harbouring TUDCA in the tunnel and LPA in the pocket, together with kinetic analysis, reveals that bile salts act as partial non-competitive inhibitors of ATX, thereby attenuating LPA receptor activation. This unexpected interplay between ATX-LPA signalling and select steroids, notably natural bile salts, provides a molecular basis for the emerging association of ATX with disorders associated with increased circulating levels of bile salts. Furthermore, our findings suggest potential clinical implications in the use of steroid drugs.

Topics: Animals; Bile Acids and Salts; Crystallography, X-Ray; HEK293 Cells; HeLa Cells; Humans; Hydroxycholesterols; Kinetics; Lysophospholipids; Models, Molecular; Molecular Conformation; Molecular Structure; Phosphoric Diester Hydrolases; Protein Binding; Protein Structure, Tertiary; Rats; Receptors, Lysophosphatidic Acid; Signal Transduction; Steroids; Taurochenodeoxycholic Acid

The mitochondrial and endoplasmic reticulum unfolded protein responses (UPR(mt) and UPR(ER)) are important for cellular homeostasis during stimulus-induced increases in protein synthesis. Exercise triggers the synthesis of mitochondrial proteins, regulated in part by peroxisome proliferator activator receptor-γ coactivator 1α (PGC-1α). To investigate the role of the UPR in exercise-induced adaptations, we subjected rats to 3 h of chronic contractile activity (CCA) for 1, 2, 3, 5, or 7 days followed by 3 h of recovery. Mitochondrial biogenesis signaling, through PGC-1α mRNA, increased 14-fold after 1 day of CCA. This resulted in 10-32% increases in cytochrome c oxidase activity, indicative of mitochondrial content, between days 3 and 7, as well as increases in the autophagic degradation of p62 and microtubule-associated proteins 1A/1B light chain 3A (LC3)-II protein. Before these adaptations, the UPR(ER) transcripts activating transcription factor-4, spliced X-box-binding protein 1, and binding immunoglobulin protein were elevated (1.3- to 3.8-fold) at days 1-3, while CCAAT/enhancer-binding protein homologous protein (CHOP) and chaperones binding immunoglobulin protein and heat shock protein (HSP) 70 were elevated at mRNA and protein levels (1.5- to 3.9-fold) at days 1-7 of CCA. The mitochondrial chaperones 10-kDa chaperonin, HSP60, and 75-kDa mitochondrial HSP, the protease ATP-dependent Clp protease proteolytic subunit, and the regulatory protein sirtuin-3 of the UPR(mt) were concurrently induced 10-80% between days 1 and 7 To test the role of the UPR in CCA-induced remodeling, we treated animals with the endoplasmic reticulum stress suppressor tauroursodeoxycholic acid and subjected them to 2 or 7 days of CCA. Tauroursodeoxycholic acid attenuated CHOP and HSP70 protein induction; however, this failed to impact mitochondrial remodeling. Our data indicate that signaling to the UPR is rapidly activated following acute contractile activity, that this is attenuated with repeated bouts, and that the UPR is involved in chronic adaptations to CCA; however, this appears to be independent of CHOP signaling.

Topics: Adaptation, Physiological; Animals; Autophagy; Endoplasmic Reticulum; Endoplasmic Reticulum Stress; Gene Expression Regulation; Male; Mitochondria, Muscle; Mitochondrial Proteins; Molecular Chaperones; Muscle Contraction; Muscle Proteins; Muscle, Skeletal; Organelle Biogenesis; Rats, Sprague-Dawley; RNA, Messenger; Signal Transduction; Taurochenodeoxycholic Acid; Time Factors; Unfolded Protein Response

Ischemic-type biliary lesions (ITBL) are the most troublesome biliary complication after liver transplantation (LT) from non-heart-beating donors (NHBD) and frequently result in death or re-transplantation. In transplantation process, warm ischemia (WI) in the donor, cold ischemia and reperfusion injury in the recipient altogether inducing ischemia-reperfusion injury (IRI) is strongly associated with ITBL. This is a cascading injury process, involving in a complex series of inter-connecting events causing variety of cells activation and damage associated with the massive release of inflammatory cytokines and generation of reactive oxygen species (ROS). These damaged cells such as sinusoidal endothelial cells (SECs), Kupffer cells (KCs), hepatocytes and biliary epithelial cells (BECs), coupled with immunological injury and bile salt toxicity altogether contribute to ITBL in NHBD LT. Developed therapeutic strategies to attenuate IRI are essential to improve outcome after LT. Among them, single pharmaceutical interventions blocking a specific pathway of IRI in rodent models play an absolutely dominant role, and show a beneficial effect in some given controlled experiments. But this will likely prove ineffective in complex clinical setting in which more risk parameters are involved. Therefore, we intend to design a multidrug cocktail approach to block different pathways on more than one stage (WI, cold ischemia and reperfusion) of the process of IRI-induced ITBL simultaneously. This multidrug cocktail will include six drugs containing streptokinase, epoprostenol, thiazolidinediones (TZDs), N-Acetylcysteine (NAC), hemin and tauroursodeoxycholic acid (TUDC). These drugs show protective effects by targeting the different key events of IRI, such as anti-inflammatory, anti-fibrosis, anti-oxidation, anti-apoptosis and reduced bile salt toxicity. Ideally, the compounds, dosage, and method of application of drugs included in cocktail should not be definitive. We can consider removing or adding some drugs to the proposed cocktail based on further research. But given the multitude of different combinations, it is extremely difficult to determent which combination is the optimization design. Nevertheless, regardless of the difficulty, our multidrug cocktail approach designed to block different mechanisms on more than one stage of IRI simultaneously may represent a future preventive and therapeutic avenue for ITBL.

Topics: Acetylcysteine; Animals; Biliary Tract Diseases; Drug Therapy, Combination; Epithelial Cells; Epoprostenol; Female; Hemin; Hepatocytes; Humans; Inflammation; Ischemia; Kupffer Cells; Liver; Liver Failure; Liver Transplantation; Models, Theoretical; Organ Preservation; Reactive Oxygen Species; Reoperation; Reperfusion Injury; Streptokinase; Swine; Taurochenodeoxycholic Acid; Thiazolidinediones; Tissue Donors; Warm Ischemia

Endoplasmic reticulum (ER) stress-induced unfolded protein response plays a critical role in inflammatory diseases, including allergic airway disease. However, the benefits of inhibiting ER stress in the treatment of allergic airway disease are not well known. Herein, we tested the therapeutic potential of a chemical chaperone, tauroursodeoxycholic acid (TUDCA), in combating allergic asthma, using a mouse model of house dust mite (HDM)-induced allergic airway disease. TUDCA was administered during the HDM-challenge phase (preventive regimen), after the HDM-challenge phase (therapeutic regimen), or therapeutically during a subsequent HDM rechallenge (rechallenge regimen). In the preventive regimen, TUDCA significantly decreased HDM-induced inflammation, markers of ER stress, airway hyperresponsiveness (AHR), and fibrosis. Similarly, in the therapeutic regimen, TUDCA administration efficiently decreased HDM-induced airway inflammation, mucus metaplasia, ER stress markers, and AHR, but not airway remodeling. Interestingly, TUDCA administered therapeutically in the HDM rechallenge regimen markedly attenuated HDM-induced airway inflammation, mucus metaplasia, ER stress markers, methacholine-induced AHR, and airway fibrotic remodeling. These results indicate that the inhibition of ER stress in the lungs through the administration of chemical chaperones could be a valuable strategy in the treatment of allergic airway diseases.

Topics: Airway Remodeling; Animals; Anti-Asthmatic Agents; Anti-Inflammatory Agents; Asthma; Drug Evaluation, Preclinical; Endoplasmic Reticulum Stress; Female; Mice, Inbred C57BL; Pyroglyphidae; Respiratory Mucosa; Taurochenodeoxycholic Acid

Ulcerative colitis is a chronic nonspecific inflammatory disease of unknown cause. The aim of this study was to evaluate the anti-inflammatory effect of tauroursodeoxycholate in 2, 4, 6-trinitrobenzenesulfonic acid-induced experimental colitis in mice. After the induction of colitis for 24h, the mice were administrated orally with tauroursodeoxycholate (20, 40 and 60mg/kg) and sulfasalazine (500mg/kg) by gavage for 7 consecutive days. The inhibition effects were evaluated by the body of weight change, survival rate, macroscopical and histological evaluations. Besides, myeloperoxidase (MPO) activity, interleukin (IL)-1β, interferon (IFN)-γ and tumour necrosis factor-α (TNF-α) in colon tissue were also determined by enzyme-linked immunosorbent assay. Treatment with different doses of tauroursodeoxycholate (20, 40 and 60mg/kg) significantly improved the body weight change, decreased the macroscopic and histopathological scores. Compared with the model group, the accumulation of MPO activity, the colonic tissue levels of IL-1β, IFN-γ and TNF-α were significantly reduced in the tauroursodeoxycholate treated groups. Moreover, tauroursodeoxycholate assuaged the symptoms of colitis. These results suggested that tauroursodeoxycholate has an anti-inflammatory effect in TNBS-induced ulcerative colitis in mice.

Topics: Acute Disease; Administration, Oral; Animals; Anti-Inflammatory Agents; Body Weight; Colitis, Ulcerative; Colon; Disease Models, Animal; Humans; Interferon-gamma; Interleukin-1beta; Male; Mice; Mice, Inbred BALB C; Peroxidase; Taurochenodeoxycholic Acid; Trinitrobenzenesulfonic Acid; Tumor Necrosis Factor-alpha

The uroguanylin-GUCY2C gut-brain axis has emerged as one component regulating feeding, energy homeostasis, body mass and metabolism. Here, we explore a role for this axis in mechanisms underlying diet-induced obesity (DIO).. Intestinal uroguanylin expression and secretion, and hypothalamic GUCY2C expression and anorexigenic signaling, were quantified in mice on high-calorie diets for 14 weeks. The role of endoplasmic reticulum (ER) stress in suppressing uroguanylin in DIO was explored using tunicamycin, an inducer of ER stress, and tauroursodeoxycholic acid (TUDCA), a chemical chaperone that inhibits ER stress. The impact of consumed calories on uroguanylin expression was explored by dietary manipulation. The role of uroguanylin in mechanisms underlying obesity was examined using Camk2a-Cre-ER(T2)-Rosa-STOP(loxP/loxP)-Guca2b mice in which tamoxifen induces transgenic hormone expression in brain.. DIO suppressed intestinal uroguanylin expression and eliminated its postprandial secretion into the circulation. DIO suppressed uroguanylin through ER stress, an effect mimicked by tunicamycin and blocked by TUDCA. Hormone suppression by DIO reflected consumed calories, rather than the pathophysiological milieu of obesity, as a diet high in calories from carbohydrates suppressed uroguanylin in lean mice, whereas calorie restriction restored uroguanylin in obese mice. However, hypothalamic GUCY2C, enriched in the arcuate nucleus, produced anorexigenic signals mediating satiety upon exogenous agonist administration, and DIO did not impair these responses. Uroguanylin replacement by transgenic expression in brain repaired the hormone insufficiency and reconstituted satiety responses opposing DIO and its associated comorbidities, including visceral adiposity, glucose intolerance and hepatic steatosis.. These studies reveal a novel pathophysiological mechanism contributing to obesity in which calorie-induced suppression of intestinal uroguanylin impairs hypothalamic mechanisms regulating food consumption through loss of anorexigenic endocrine signaling. The correlative therapeutic paradigm suggests that, in the context of hormone insufficiency with preservation of receptor sensitivity, obesity may be prevented or treated by GUCY2C hormone replacement.

Topics: Animals; Arcuate Nucleus of Hypothalamus; Caloric Restriction; Diet; Endoplasmic Reticulum Stress; Energy Intake; Fatty Liver; Gene Expression Regulation; Gene Silencing; Glucose Intolerance; Hormone Replacement Therapy; Intestinal Mucosa; Mice; Mice, Inbred C57BL; Mice, Obese; Mice, Transgenic; Natriuretic Peptides; Obesity; Postprandial Period; Receptors, Enterotoxin; Receptors, Guanylate Cyclase-Coupled; Receptors, Peptide; Satiation; Signal Transduction; Taurochenodeoxycholic Acid; Tunicamycin

Recent studies have demonstrated that cyanobacteria-derived Microcystin-LR (MC-LR) can cause developmental toxicity and trigger apoptosis in zebrafish (Danio rerio) larvae, but the underlying mechanisms remain largely unknown. In this study, we tested the hypothesis that the mechanism by which MC-LR induces developmental toxicity is through activation of endoplasmic reticulum (ER) stress. MC-LR (4.0 μM) exposure through submersion caused serious developmental toxicity, such as malformation, growth delay and decreased heart rates in zebrafish larvae, which could be inhibited by ER stress blocker, tauroursodeoxycholic acid (TUDCA, 20 μM). Meanwhile, acridine orange (AO) staining showed TUDCA could rescue cell apoptosis in heart area in zebrafish larvae resulted by MC-LR exposure. Real-time polymerase chain reaction (real-time PCR) analysis demonstrated that MC-LR induced activation of ER stress which consequently triggered apoptosis in zebrafish larvae. Protein expression examined by western blot indicated that MC-LR could activate MAPK8/Bcl-2/Bax pathway and caspase-dependent apoptotic pathway in zebrafish larva and the effects were mitigated by inhibition of ER stress. Taken together, the results observed in this study suggested that ER stress plays a critical role in developmental toxicity and apoptosis in zebrafish embryos exposed to MC-LR.

Topics: Animals; Apoptosis; Bacterial Toxins; Dose-Response Relationship, Drug; Endoplasmic Reticulum Stress; Marine Toxins; Microcystins; Random Allocation; Taurochenodeoxycholic Acid; Water Pollutants, Chemical; Zebrafish

Castration-resistant prostate cancer (CRPC) is a major cause of prostate cancer (Pca) death. Chemotherapy is able to improve the survival of CRPC patients. We previously found that NSC606985 (NSC), a highly water-soluble camptothecin analog, induced cell death in Pca cells via interaction with topoisomerase 1 and activation of the mitochondrial apoptotic pathway. To further elucidate the role of NSC, we studied the effect of NSC on ER-stress and its association with NSC-induced cell death in Pca cells. NSC produced a time- and dose-dependent induction of GRP78, CHOP and XBP1s mRNA, and CHOP protein expression in Pca cells including DU145, indicating an activation of ER-stress. However, unlike conventional ER-stress in which GRP78 protein is increased, NSC produced a time- and dose-dependent U-shape change in GRP78 protein in DU145 cells. The NSC-induced decrease in GRP78 protein was blocked by protease inhibitors, N-acetyl-L-leucyl-L-leucylnorleucinal (ALLN), a lysosomal protease inhibitor, and epoxomicin (EPO), a ubiquitin-protease inhibitor. ALLN, but not EPO, also partially inhibited NSC-induced cell death. However, both 4-PBA and TUDCA, two chemical chaperons that effectively reduced tunicamycin-induced ER-stress, failed to attenuate NSC-induced GRP78, CHOP and XBP1s mRNA expression and cell death. Moreover, knockdown of NSC induction of CHOP expression using a specific siRNA had no effect on NSC-induced cytochrome c release and NSC-induced cell death. These results suggest that NSC produced an atypical ER-stress that is dissociated from NSC-induced activation of the mitochondrial apoptotic pathway and NSC-induced cell death in DU145 prostate cancer cells.

Topics: Apoptosis; Butylamines; Camptothecin; Cell Line, Tumor; Endoplasmic Reticulum Chaperone BiP; Endoplasmic Reticulum Stress; Heat-Shock Proteins; Humans; Male; Prostatic Neoplasms, Castration-Resistant; Protease Inhibitors; Taurochenodeoxycholic Acid

Unfolded or misfolded protein accumulation in the endoplasmic reticulum lumen leads to endoplasmic reticulum stress (ER stress). Although it is known that ER stress is crucial for mammalian reproduction, little is known about its physiological significance and underlying mechanism during decidualization. Here we show that Ire-Xbp1 signal transduction pathway of unfolded protein response (UPR) is activated in decidual cells. The process of decidualization is compromised by ER stress inhibitor tauroursodeoxycholic acid sodium (TUDCA) and Ire specific inhibitor STF-083010 both in vivo and in vitro. A high concentration of ER stress inducer tunicamycin (TM) suppresses stromal cells proliferation and decidualization, while a lower concentration is beneficial. We further show that ER stress induces DNA damage and polyploidization in stromal cells. In conclusion, our data suggest that the GRP78/Ire1/Xbp1 signaling pathway of ER stress-UPR is activated and involved in mouse decidualization.

Topics: Animals; Cell Proliferation; Decidua; Endoplasmic Reticulum Chaperone BiP; Endoplasmic Reticulum Stress; Endoribonucleases; Female; Heat-Shock Proteins; Mice; Pregnancy; Protein Serine-Threonine Kinases; Signal Transduction; Stromal Cells; Sulfonamides; Taurochenodeoxycholic Acid; Thiophenes; Tunicamycin; Unfolded Protein Response; X-Box Binding Protein 1

Diabetes severely impairs male reproduction. The present study assessed the effects and mechanisms of action of advanced glycation end products (AGEs), which play an important role in the development of diabetes complications, on testosterone secretion by rat Leydig cells. Primary rat Leydig cells were cultured and treated with AGEs (25, 50, 100 and 200 µg/ml). Testosterone production induced by human chorionic gonadotropin (hCG) was determined by ELISA. The mRNA and protein expression levels of steroidogenic acute regulatory protein (StAR), cholesterol side-chain cleavage enzyme (P450scc) and 3β-hydroxysteroid dehydrogenase (3β-HSD), which are involved in testosterone biosynthesis, were measured by reverse transcription-quantitative PCR and western blot analyssi, respectively. Reactive oxygen species (ROS) production in Leydig cells was measured using the dichlorofluorescein diacetate (DCFH-DA) probe. The expression levels of endoplasmic reticulum stress-related proteins [C/EBP homologous protein (CHOP) and glucose-regulated protein 78 (GRP78)] in the Leydig cells were measured by western blot analysis. We found that the AGEs markedly suppressed testosterone production by rat Leydig cells which was induced by hCG in a concentration-dependent manner compared with the control (P<0.01). The mRNA and protein expression levels of StAR, 3β-HSD and P450scc were downregulated by the AGEs in a dose-dependent manner compared with the control (P<0.01). The antioxidant agent, N-acetyl‑L‑cysteine (NAC), and the endoplasmic reticulum stress inhibitor, tauroursodeoxycholic acid (TUDCA), reversed the inhibitory effects of AGEs. In addition, the content of ROS in Leydig cells treated with AGEs increased significantly. The expression levels of CHOP and GRP78 were markedly upregulated by the AGEs in the Leydig cells. From these findings, it can be concluded that AGEs inhibit testosterone production by rat Leydig cells by inducing oxidative stress and endoplasmic reticulum stress.

Topics: 17-Hydroxysteroid Dehydrogenases; Acetylcysteine; Animals; Cell Survival; Cholesterol Side-Chain Cleavage Enzyme; Chorionic Gonadotropin; Endoplasmic Reticulum Chaperone BiP; Endoplasmic Reticulum Stress; Glycation End Products, Advanced; Humans; Leydig Cells; Male; Oxidative Stress; Phosphoproteins; Rats, Sprague-Dawley; RNA, Messenger; Taurochenodeoxycholic Acid; Testosterone; Transcription Factor CHOP

Transthyretin (TTR)-related amyloidoses are diseases characterized by extracellular deposition of amyloid fibrils and aggregates in tissues composed of insoluble misfolded TTR that becomes toxic. Previous studies have demonstrated the ability of small compounds in preventing and reversing TTR V30M deposition in transgenic mice gastrointestinal (GI) tract as well as lowering biomarkers associated with cellular stress and apoptotic mechanisms. In the present study we aimed to study TTR V30M aggregates effect in autophagy, a cellular mechanism crucial for cell survival that has been implicated in the development of several neurodegenerative diseases. We were able to demonstrate in cell culture that TTR V30M aggregates cause a partial impairment of the autophagic machinery as shown by p62 accumulation, whereas early steps of the autophagic flux remain unaffected as shown by autophagosome number evaluation and LC3 turnover assay. Our studies performed in TTR V30M transgenic animals demonstrated that tauroursodeoxycholic acid (TUDCA) and curcumin effectively reverse p62 accumulation in the GI tract pointing to the ability of both compounds to modulate autophagy additionally to mitigate apoptosis. Overall, our in vitro and in vivo studies establish an association between TTR V30M aggregates and autophagy impairment and suggest the use of autophagy modulators as an additional and alternative therapeutic approach for the treatment of TTR V30M-related amyloidosis.

Topics: Amyloid Neuropathies, Familial; Animals; Autophagy; Curcumin; Disease Models, Animal; Female; Humans; Male; Mice; Mice, Transgenic; Mutation, Missense; Prealbumin; Protein Aggregates; Taurochenodeoxycholic Acid

The aim of this work was to determine whether placental endoplasmic reticulum (ER) stress may contribute to the pathophysiology of gestational diabetes mellitus (GDM) and to test the efficacy of chemical chaperones and antioxidant vitamins in ameliorating that stress in a trophoblast-like cell line in vitro.. Placental samples were obtained from women suffering from GDM and from normoglycaemic controls and were frozen immediately. Women with GDM had 2 h serum glucose levels > 9.0 mmol/l following a 75 g oral glucose tolerance test and were treated with diet and insulin when necessary. Western blotting was used to assess markers of ER stress. To test the effects of hyperglycaemia on the generation of ER stress, a new trophoblast-like cell line, BeWo-NG, was generated by culturing in a physiological glucose concentration of 5.5 mmol/l (over 20 passages) before challenging with 10 or 20 mmol/l glucose.. All GDM patients were well-controlled (HbA1c 5.86 ± 0.55% or 40.64 ± 5.85 mmol/mol, n = 11). Low-grade ER stress was observed in the placental samples, with dilation of ER cisternae and increased phosphorylation of eukaryotic initiation factor 2 subunit α. Challenge of BeWo-NG with high glucose activated the same pathways, but this was as a result of acidosis of the culture medium rather than the glucose concentration per se. Addition of chemical chaperones 4-phenylbutyrate and tauroursodeoxycholic acid and vitamins C and E ameliorated the ER stress.. This is the first report of placental ER stress in GDM patients. Chemical chaperones and antioxidant vitamins represent potential therapeutic interventions for GDM.

Topics: Acidosis; Adult; Antioxidants; Ascorbic Acid; Blood Glucose; Blotting, Western; Cell Line; Diabetes, Gestational; Endoplasmic Reticulum Stress; Eukaryotic Initiation Factor-2; Female; Glucose; Humans; Phenylbutyrates; Phosphorylation; Placenta; Pregnancy; Taurochenodeoxycholic Acid; Unfolded Protein Response; Vitamin E

Cardiac fibrosis attributed to excessive deposition of extracellular matrix proteins is a major cause of heart failure and death. Cardiac fibrosis is extremely difficult and challenging to treat in a clinical setting due to lack of understanding of molecular mechanisms leading to cardiac fibrosis and effective anti-fibrotic therapies. The objective in this study was to examine whether unfolded protein response (UPR) pathway mediates cardiac fibrosis and whether a pharmacological intervention to modulate UPR can prevent cardiac fibrosis and preserve heart function.. We demonstrate here that the mechanism leading to development of fibrosis in a mouse with increased expression of calreticulin, a model of heart failure, stems from impairment of endoplasmic reticulum (ER) homeostasis, transient activation of the unfolded protein response (UPR) pathway and stimulation of the TGFβ1/Smad2/3 signaling pathway. Remarkably, sustained pharmacologic inhibition of the UPR pathway by tauroursodeoxycholic acid (TUDCA) is sufficient to prevent cardiac fibrosis, and improved exercise tolerance.. We show that the mechanism leading to development of fibrosis in a mouse model of heart failure stems from transient activation of UPR pathway leading to persistent remodelling of cardiac tissue. Blocking the activation of the transiently activated UPR pathway by TUDCA prevented cardiac fibrosis, and improved prognosis. These findings offer a window for additional interventions that can preserve heart function.

Topics: Animals; Calreticulin; Cell Adhesion Molecules; Collagen; Endoribonucleases; Fibrosis; Mice; Myocardium; Protein Serine-Threonine Kinases; RNA Splicing; RNA, Messenger; Taurochenodeoxycholic Acid; Transforming Growth Factor beta1; Unfolded Protein Response; X-Box Binding Protein 1

We previously reported that endoplasmic reticulum (ER) stress is induced in the subfornical organ (SFO) and the hypothalamic paraventricular nucleus (PVN) of heart failure (HF) rats and is reduced by inhibition of mitogen-activated protein kinase (MAPK) signaling. The present study further examined the relationship between brain MAPK signaling, ER stress, and sympathetic excitation in HF. Sham-operated (Sham) and HF rats received a 4-wk intracerebroventricular (ICV) infusion of vehicle (Veh) or the ER stress inhibitor tauroursodeoxycholic acid (TUDCA, 10 μg/day). Lower mRNA levels of the ER stress biomarkers GRP78, ATF6, ATF4, and XBP-1s in the SFO and PVN of TUDCA-treated HF rats validated the efficacy of the TUDCA dose. The elevated levels of phosphorylated p44/42 and p38 MAPK in SFO and PVN of Veh-treated HF rats, compared with Sham rats, were significantly reduced in TUDCA-treated HF rats as shown by Western blot and immunofluorescent staining. Plasma norepinephrine levels were higher in Veh-treated HF rats, compared with Veh-treated Sham rats, and were significantly lower in the TUDCA-treated HF rats. TUDCA-treated HF rats also had lower mRNA levels for angiotensin converting enzyme, angiotensin II type 1 receptor, tumor necrosis factor-α, interleukin-1β, cyclooxygenase-2, and NF-κB p65, and a higher mRNA level of IκB-α, in the SFO and PVN than Veh-treated HF rats. These data suggest that ER stress contributes to the augmented sympathetic activity in HF by inducing MAPK signaling, thereby promoting inflammation and renin-angiotensin system activity in key cardiovascular regulatory regions of the brain.

Topics: Activating Transcription Factor 4; Activating Transcription Factor 6; Animals; Blotting, Western; Brain; Cholagogues and Choleretics; Cyclooxygenase 2; Echocardiography; Endoplasmic Reticulum Stress; Heart Failure; Heat-Shock Proteins; Inflammation; Infusions, Intraventricular; Interleukin-1beta; Male; Mitogen-Activated Protein Kinase 1; Mitogen-Activated Protein Kinase 3; Mitogen-Activated Protein Kinases; NF-KappaB Inhibitor alpha; p38 Mitogen-Activated Protein Kinases; Paraventricular Hypothalamic Nucleus; Peptidyl-Dipeptidase A; Rats; Rats, Sprague-Dawley; Real-Time Polymerase Chain Reaction; Receptor, Angiotensin, Type 1; Renin-Angiotensin System; RNA, Messenger; Signal Transduction; Subfornical Organ; Sympathetic Nervous System; Taurochenodeoxycholic Acid; Transcription Factor RelA; Tumor Necrosis Factor-alpha; X-Box Binding Protein 1

Endoplasmic reticulum (ER) stress has been shown to play a critical role in the pathogenesis of cardiovascular complications. However, the role and mechanisms of ER stress in hypertension remain unclear. Thus, we hypothesized that enhanced ER stress contributes to the maintenance of hypertension in spontaneously hypertensive rats (SHRs). Sixteen-week old male SHRs and Wistar Kyoto Rats (WKYs) were used in this study. The SHRs were treated with ER stress inhibitor (Tauroursodeoxycholic acid; TUDCA, 100 mg/kg/day) for two weeks. There was a decrease in systolic blood pressure in SHR treated with TUDCA. The pressure-induced myogenic tone was significantly increased, whereas endothelium-dependent relaxation was significantly attenuated in SHR compared with WHY. Interestingly, treatment of ER stress inhibitor normalized myogenic responses and endothelium-dependent relaxation in SHR. These data were associated with an increase in expression or phosphorylation of ER stress markers (Bip, ATF6, CHOP, IRE1, XBP1, PERK, and eIF2α) in SHRs, which were reduced by TUDCA treatment. Furthermore, phosphorylation of MLC20 was increased in SHRs, which was reduced by the treatment of TUDCA. Therefore, our results suggest that ER stress could be a potential target for hypertension.

Topics: Animals; Biomarkers; Coronary Vessels; Disease Models, Animal; Drug Administration Schedule; Endoplasmic Reticulum Stress; Gene Expression Regulation; Hypertension; Male; Phosphorylation; Rats; Rats, Inbred SHR; Rats, Inbred WKY; Taurochenodeoxycholic Acid

Tauroursodeoxycholic acid (TUDCA) is known to prevent apoptosis through the Bax pathway and to promote neovascularization by enhancing the mobilization of stem cells, their differentiation. This study was performed to investigate the effect of TUDCA on erythropoiesis in hematopoietic stem cells (HSCs). Since erythropoiesis of CD34(+) HSCs is divided into four phases, the total cell number, viable cell number, cell viability, cell morphology, and expressed erythroid markers in each phase were examined. The number of viable control cells and their viability did not differ from those of the TUDCA-treated cells in phase I and II. However, TUDCA increased cell viability compared to the control in phases III and IV. Cell distribution differed that the immature erythroid cell number was higher for the TUDCA-treated cells than for the control cells until phase III, but all developed into RBCs in the last. The final RBC number and viability was significantly higher in TUDCA-treated cells compared to the control cells. Taken together, we suggest that TUDCA addition to cell cultures for artificial RBC production could be used as a new protocol for improving the viability of RBCs.

Topics: Adult; Aged; Antigens, CD34; Biomarkers; Cell Differentiation; Cell Survival; Cells, Cultured; Cholagogues and Choleretics; Erythrocyte Count; Erythrocytes; Erythroid Cells; Erythropoiesis; Female; Flow Cytometry; Hematopoietic Stem Cells; Humans; Immunophenotyping; Male; Middle Aged; Taurochenodeoxycholic Acid; Time Factors

Renal tubular injury is a critical factor in the pathogenesis of diabetic nephropathy (DN). Endoplasmic reticulum (ER) stress is involved in diabetic nephropathy. Tauroursodeoxycholic acid (TUDCA) is an effective inhibitor of ER stress. Here, we investigated the role of TUDCA in the progression of tubular injury in DN. For eight weeks, being treated with TUDCA at 250 mg/kg intraperitoneal injection (i.p.) twice a day, diabetic db/db mice had significantly reduced blood glucose, albuminuria and attenuated renal histopathology. These changes were associated with a significant decreased expression of ER stress markers. At the same time, diabetic db/db mice had more TUNEL-positive nuclei in the renal tubule, which were attenuated by TUDCA treatment, along with decreases in ER stress-associated apoptotic markers in the kidneys. In summary, the effect of TUDCA on tubular injury, in part, is associated with inhibition of ER stress in the kidneys of diabetic db/db mice. TUDCA shows potential as a therapeutic target for the prevention and treatment of DN.

Topics: Animals; Apoptosis; Biomarkers; Diabetes Mellitus, Type 2; Diabetic Nephropathies; Endoplasmic Reticulum; Kidney Tubules; Male; Mice; Mice, Inbred NOD; Stress, Physiological; Taurochenodeoxycholic Acid

Sepsis-induced lymphopenia is a major cause of morbidities in intensive care units and in populations with chronic conditions such as renal failure, diabetes, HIV and alcohol abuse. Currently, other than supportive care and antibiotics, there are no treatments for this condition. We developed an in vitro assay to understand the role of the ER-stress-mediated apoptosis process in lymphocyte death during polymicrobial sepsis, which was reproducible in in vivo mouse models. Modulating ER stress using chemical chaperones significantly reduced the induction of the pro-apoptotic protein Bim both in vitro and in mice. Furthermore, in a 'two-hit' pneumonia model in mice, we have been able to demonstrate that administration of the chemical chaperone TUDCA helped to maintain lymphocyte homeostasis by significantly reducing lymphocyte apoptosis and this correlated with four-fold improvement in survival. Our results demonstrate a novel therapeutic opportunity for treating sepsis-induced lymphopenia in humans.

Topics: Animals; Apoptosis; Bcl-2-Like Protein 11; Cell Line; Cell Line, Tumor; Cholagogues and Choleretics; Disease Models, Animal; Endoplasmic Reticulum Stress; Female; Humans; Lymphocytes; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; RAW 264.7 Cells; Sepsis; Survival Analysis; Taurochenodeoxycholic Acid; U937 Cells

Functionally compromised neutrophils contribute to adverse clinical outcomes in patients with severe inflammation and injury such as colitis and sepsis. However, the ontogeny of dysfunctional neutrophil during septic colitis remain poorly understood. We report that the dysfunctional neutrophil may be derived by the suppression of Toll-interacting-protein (Tollip). We observed that Tollip deficient neutrophils had compromised migratory capacity toward bacterial product fMLF due to reduced activity of AKT and reduction of FPR2, reduced potential to generate bacterial-killing neutrophil extra-cellular trap (NET), and compromised bacterial killing activity. On the other hand, Tollip deficient neutrophils had elevated levels of CCR5, responsible for their homing to sterile inflamed tissues. The inflamed and incompetent neutrophil phenotype was also observed in vivo in Tollip deficient mice subjected to DSS-induced colitis. We observed that TUDCA, a compound capable of restoring Tollip cellular function, can potently alleviate the severity of DSS-induced colitis. In humans, we observed significantly reduced Tollip levels in peripheral blood collected from human colitis patients as compared to blood samples from healthy donors. Collectively, our data reveal a novel mechanism in Tollip alteration that underlies the inflamed and incompetent polarization of neutrophils leading to severe outcomes of colitis.

Topics: Adult; Animals; Colitis; Dextran Sulfate; Disease Models, Animal; Down-Regulation; Female; Humans; Intracellular Signaling Peptides and Proteins; Leukocytes; Male; Mice; Middle Aged; Receptors, CCR5; Sepsis; Taurochenodeoxycholic Acid; Young Adult

Aldosterone (Aldo) is critically involved in the development of renal injury via the production of reactive oxygen species and inflammation. Endoplasmic reticulum (ER) stress is also evoked in Aldo-induced renal injury. In the present study, we investigated the role of ER stress in inflammation-mediated renal injury in Aldo-infused mice. C57BL/6J mice were randomized to receive treatment for 4 weeks as follows: vehicle infusion, Aldo infusion, vehicle infusion plus tauroursodeoxycholic acid (TUDCA), and Aldo infusion plus TUDCA. The effect of TUDCA on the Aldo-infused inflammatory response and renal injury was investigated using periodic acid-Schiff staining, real-time PCR, Western blot, and ELISA. We demonstrate that Aldo leads to impaired renal function and inhibition of ER stress via TUDCA attenuates renal fibrosis. This was indicated by decreased collagen I, collagen IV, fibronectin, and TGF-

Topics: Aldosterone; Animals; Blotting, Western; Endoplasmic Reticulum; Enzyme-Linked Immunosorbent Assay; Kidney; Kidney Diseases; Mice; Mice, Inbred C57BL; Reactive Oxygen Species; Real-Time Polymerase Chain Reaction; Taurochenodeoxycholic Acid

Tauroursodeoxycholic acid (TUDCA) is a cytoprotective ER stress inhibitor and chemical chaperone. It has therapeutic potential in a wide array of diseases but a specific macromolecular target or molecular mechanism of action remains obscure. This Letter describes an effective new synthetic approach to taurine conjugation of bile acids which we used to prepare 3α-dansyl TUDCA (4) as a probe for TUDCA actions. As a model of ER stress we used the hepatocarcinoma cell line HUH7 and stimulation with either deoxycholic acid (DCA, 200μM) or tunicamycin (5μg/ml) and measured levels of Bip/GRP78, ATF4, CHOP and XBP1s/XBP1u. Compound 4 was more effective than UDCA at inhibiting ER stress markers and had similar effects to TUDCA. In a model of cholestasis using the cytotoxic DCA to induce apoptosis, pretreatment with 4 prevented cell death similarly to TUDCA whereas the unconjugated clinically used UDCA had no effect. 3α-Dansyl TUDCA (4) appears to be a suitable reporter for TUDCA effects on ER stress and related cytoprotective activity.

Topics: Animals; Endoplasmic Reticulum Chaperone BiP; Endoplasmic Reticulum Stress; Fluorescent Dyes; Humans; Taurochenodeoxycholic Acid

The aim of this study is to investigate whether endoplasmic reticulum (ER) stress attenuation could improve porcine somatic cell nuclear transfer (SCNT) embryo developmental competence. We treated porcine SCNT embryos with TUDCA (tauroursodeoxycholic acid, an inhibitor of ER stress) and/or TM (tunicamycin, an ER stress inducer), and examined embryonic developmental potential, embryo quality, the levels of ER stress markers (XBP1 protein and mRNA) and apoptosis-related-genes (BAX and BCL2 mRNA). Immunostaining detected X-box-binding protein (XBP1), a key gene regulator during ER stress, at all stages of SCNT embryo development. Embryo development analysis revealed that TUDCA treatment markedly increased (p<0.05) blastocyst formation rate, total cell number and inner cell mass (ICM) cell number compared to untreated control group. The TUDCA and TM groups showed significant alterations in XBP1 protein and XBP1-s mRNA levels compared to controls (lower and higher, respectively; p<0.05). Also, TUDCA treatment reduced oxidative stress by up-regulation of the antioxidant, GSH. TUNEL assay showed that TUDCA treatment significantly reduced apoptosis in porcine SCNT blastocysts confirmed by decreased pro-apoptotic BAX and increased anti-apoptotic BCL2 mRNA levels. Collectively, our results indicated that TUDCA can enhance the developmental potential of porcine SCNT embryos by attenuating ER-stress and reducing apoptosis.

Topics: Animals; Apoptosis; Embryo Implantation; Embryo, Mammalian; Embryonic Development; Endoplasmic Reticulum Stress; Nuclear Transfer Techniques; Swine; Taurochenodeoxycholic Acid; Up-Regulation

2,4-Dichlorophenol (2,4-DCP) is an environmental pollutant exhibiting a wide spectrum of toxic effects. We investigated the toxic effects and potential mechanisms underlying 2,4-DCP-induced hepatotoxicity. In vitro, 2,4-DCP caused hepatotoxicity manifested by a decrease in cell viability and inhibition of colony formation. Bip and CHOP expression was up-regulated at the mRNA and protein levels. Moreover, 2,4-DCP induced eIF2α phosphorylation and Xbp1 mRNA splicing, indicating that endoplasmic reticulum (ER) stress was activated after exposure of HL7702 cells to 2,4-DCP for 12 hr. Furthermore, the mitochondrial membrane potential collapsed and apoptosis was triggered after exposure to 2,4-DCP for 24 hr. In vivo, 2,4-DCP caused histological changes in the liver, and dramatically elevated the serum alanine transaminase (ALT) and aspartate aminotransferase (AST) levels of mice. ER stress was also triggered in the liver of mice on days 1 and 3. The ER stress inhibitor TUDCA could partly relieve the liver damage, as indicated by the restoration of serum ALT and AST levels. Taken together, our results demonstrated that ER stress may serve as an early warning mechanism against 2,4-DCP-induced hepatotoxicity, and severe ER stress may lead to apoptosis.

Topics: Alanine Transaminase; Animals; Apoptosis; Aspartate Aminotransferases; Cell Line; Cell Proliferation; Cell Survival; Chemical and Drug Induced Liver Injury; Chlorophenols; Dose-Response Relationship, Drug; Endoplasmic Reticulum Chaperone BiP; Endoplasmic Reticulum Stress; Environmental Pollutants; Eukaryotic Initiation Factor-2; Heat-Shock Proteins; Humans; Liver; Male; Membrane Potential, Mitochondrial; Mice; Phosphorylation; RNA, Messenger; Taurochenodeoxycholic Acid; Transcription Factor CHOP; Up-Regulation; X-Box Binding Protein 1

Although mesenchymal stem cells (MSCs) are a promising cell source for regenerative medicine, ischemia-induced endoplasmic reticulum (ER) stress induces low MSC engraftment and limits their therapeutic efficacy. To overcome this, we investigated the protective effect of tauroursodeoxycholic acid (TUDCA), a bile acid, on ER stress in MSCs in vitro and in vivo. In ER stress conditions, TUDCA treatment of MSCs reduced the activation of ER stress-associated proteins, including GRP78, PERK, eIF2α, ATF4, IRE1α, JNK, p38, and CHOP. In particular, TUDCA inhibited the dissociation between GRP78 and PERK, resulting in reduced ER stress-mediated cell death. Next, to explore the ER stress protective mechanism induced by TUDCA treatment, TUDCA-mediated cellular prion protein (PrP

Topics: Animals; Endoplasmic Reticulum Chaperone BiP; Endoplasmic Reticulum Stress; Heterografts; Humans; Male; Mesenchymal Stem Cell Transplantation; Mesenchymal Stem Cells; Mice, Inbred BALB C; Mice, Nude; Proto-Oncogene Proteins c-akt; PrPC Proteins; Signal Transduction; Taurochenodeoxycholic Acid

Sleep fragmentation (SF) is highly prevalent and may constitute an important contributing factor to excessive weight gain and the metabolic syndrome. Increased endoplasmic reticulum (ER) stress and activation of the unfolded protein response (UPR) leading to the attenuation of leptin receptor signaling in the hypothalamus leads to obesity and metabolic dysfunction.. Mice were exposed to SF and sleep control (SC) for varying periods of time during which ingestive behaviors were monitored. UPR pathways and leptin receptor signaling were assessed in hypothalami. To further examine the mechanistic role of ER stress, changes in leptin receptor (ObR) signaling were also examined in wild-type mice treated with the ER chaperone tauroursodeoxycholic acid (TUDCA), as well as in CHOP-/+ transgenic mice.. Fragmented sleep in male mice induced increased food intake starting day 3 and thereafter, which was preceded by increases in ER stress and activation of all three UPR pathways in the hypothalamus. Although ObR expression was unchanged, signal transducer and activator of transcription 3 (STAT3) phosphorylation was decreased, suggesting reduced ObR signaling. Unchanged suppressor of cytokine signaling-3 (SOCS3) expression and increases in protein-tyrosine phosphatase 1B (PTP1B) expression and activity emerged with SF, along with reduced p-STAT3 responses to exogenous leptin. SF-induced effects were reversed following TUDCA treatment and were absent in CHOP -/+ mice.. SF induces hyperphagic behaviors and reduced leptin signaling in hypothalamus that are mediated by activation of ER stress, and ultimately lead to increased PTP1B activity. ER stress pathways are therefore potentially implicated in SF-induced weight gain and metabolic dysfunction, and may represent a viable therapeutic target.

Topics: Animals; Eating; Endoplasmic Reticulum Stress; Heterozygote; Hyperphagia; Hypothalamus; Leptin; Male; Mice; Mice, Inbred C57BL; Mice, Transgenic; Obesity; Protein Tyrosine Phosphatase, Non-Receptor Type 1; Receptors, Leptin; Signal Transduction; Sleep; Sleep Deprivation; STAT3 Transcription Factor; Taurochenodeoxycholic Acid; Transcription Factor CHOP; Unfolded Protein Response

Although serum bile acid concentrations are approximately 10 µM in healthy subjects, the crosstalk between the biliary system and vascular repair has never been investigated. In this study, tauroursodeoxycholic acid (TUDCA) induced dissociation of CD34(+) hematopoietic stem cells (HSCs) from stromal cells by reducing adhesion molecule expression. TUDCA increased CD34(+) /Sca1(+) progenitors in mice peripheral blood (PB), and CD34(+) , CD31(+) , and c-kit(+) progenitors in human PB. In addition, TUDCA increased differentiation of CD34(+) HSCs into EPC lineage cells via Akt activation. EPC invasion was increased by TUDCA, which was mediated by fibroblast activating protein via Akt activation. Interestingly, TUDCA induced integration of EPCs into human aortic endothelial cells (HAECs) by increasing adhesion molecule expression. In the mouse hind limb ischemia model, TUDCA promoted blood perfusion by enhancing angiogenesis through recruitment of Flk-1(+) /CD34(+) and Sca-1(+) /c-kit(+) progenitors into damaged tissue. In GFP(+) bone marrow-transplanted hind limb ischemia, TUDCA induced recruitment of GFP(+) /c-kit(+) progenitors to the ischemic area, resulting in an increased blood perfusion ratio. Histological analysis suggested that GFP(+) progenitors mobilized from bone marrow, integrated into blood vessels, and differentiated into VEGFR(+) cells. In addition, TUDCA decreased cellular senescence by reducing levels of p53, p21, and reactive oxygen species and increased nitric oxide. Transplantation of TUDCA-primed senescent EPCs in hind limb ischemia significantly improved blood vessel regeneration, as compared with senescent EPCs. Our results suggested that TUDCA promoted neovascularization by enhancing the mobilization of stem/progenitor cells from bone marrow, their differentiation into EPCs, and their integration with preexisting endothelial cells.

Topics: Adult; Animals; Blood Vessels; Cell Differentiation; Endothelial Cells; Female; Hematopoietic Stem Cells; Humans; Male; Mice; Mice, Inbred BALB C; Mice, Inbred C57BL; Mice, Nude; Neovascularization, Pathologic; Stem Cells; Taurochenodeoxycholic Acid

Alzheimer's disease (AD) is a neurodegenerative disorder hallmarked by the accumulation of extracellular amyloid-β (Aβ) peptide and intraneuronal hyperphosphorylated tau, as well as chronic neuroinflammation. Tauroursodeoxycholic acid (TUDCA) is an endogenous anti-apoptotic bile acid with potent neuroprotective properties in several experimental models of AD. We have previously reported the therapeutic efficacy of TUDCA treatment before amyloid plaque deposition in APP/PS1 double-transgenic mice. In the present study, we evaluated the protective effects of TUDCA when administrated after the onset of amyloid pathology. APP/PS1 transgenic mice with 7 months of age were injected intraperitoneally with TUDCA (500 mg/kg) every 3 days for 3 months. TUDCA treatment significantly attenuated Aβ deposition in the brain, with a concomitant decrease in Aβ₁₋₄₀ and Aβ₁₋₄₂ levels. The amyloidogenic processing of amyloid precursor protein was also reduced, indicating that TUDCA interferes with Aβ production. In addition, TUDCA abrogated GSK3β hyperactivity, which is highly implicated in tau hyperphosphorylation and glial activation. This effect was likely dependent on the specific activation of the upstream kinase, Akt. Finally, TUDCA treatment decreased glial activation and reduced proinflammatory cytokine messenger RNA expression, while partially rescuing synaptic loss. Overall, our results suggest that TUDCA is a promising therapeutic strategy not only for prevention but also for treatment of AD after disease onset.

Topics: Alzheimer Disease; Amyloid beta-Peptides; Amyloid beta-Protein Precursor; Animals; Cholagogues and Choleretics; Cytokines; Disease Models, Animal; Gene Expression; Glycogen Synthase Kinase 3; Glycogen Synthase Kinase 3 beta; Inflammation Mediators; Mice, Transgenic; Molecular Targeted Therapy; Neuroprotective Agents; Presenilin-1; Protein Aggregation, Pathological; RNA, Messenger; tau Proteins; Taurochenodeoxycholic Acid

Diabetes mellitus increases morbidity/mortality of ischemic heart disease. Although atrial natriuretic peptide and C-type natriuretic peptide reduce the myocardial ischemia-reperfusion damage in nondiabetic rats, whether vasonatrin peptide (VNP), the artificial synthetic chimera of atrial natriuretic peptide and C-type natriuretic peptide, confers cardioprotective effects against ischemia-reperfusion injury, especially in diabetic patients, is still unclear. This study was designed to investigate the effects of VNP on ischemia-reperfusion injury in diabetic rats and to further elucidate its mechanisms. The high-fat diet-fed streptozotocin-induced diabetic Sprague-Dawley rats were subjected to ischemia-reperfusion operation. VNP treatment (100 μg/kg iv, 10 min before reperfusion) significantly improved the instantaneous first derivation of left ventricle pressure (±LV dP/dtmax) and LV systolic pressure and reduced LV end-diastolic pressure, apoptosis index, caspase-3 activity, plasma creatine kinase (CK), and lactate dehydrogenase (LDH) activities. Moreover, VNP inhibited endoplasmic reticulum (ER) stress by suppressing glucose-regulated protein 78 (GRP78) and C/EBP homologous protein (CHOP). These effects were mimicked by 8-bromine-cyclic guanosinemonophosphate (8-Br-cGMP), a cGMP analog, whereas they were inhibited by KT-5823, the selective inhibitor of PKG. In addition, pretreatment with tauroursodeoxycholic acid (TUDCA), a specific inhibitor of ER stress, could not further promote the VNP's cardioprotective effect in diabetic rats. In vitro H9c2 cardiomyocytes were subjected to hypoxia/reoxygenation and incubated with or without VNP (10(-8) mol/l). Gene knockdown of PKG1α with siRNA blunted VNP inhibition of ER stress and apoptosis, while overexpression of PKG1α resulted in significant decreased ER stress and apoptosis. VNP protects the diabetic heart against ischemia-reperfusion injury by inhibiting ER stress via the cGMP-PKG signaling pathway. These results suggest that VNP may have potential therapeutic value for the diabetic patients with ischemic heart disease.

Topics: Animals; Apoptosis; Atrial Natriuretic Factor; Carbazoles; Caspase 3; Cell Hypoxia; Cell Line; Creatine Kinase; Cyclic GMP; Cyclic GMP-Dependent Protein Kinase Type I; Diabetes Mellitus, Experimental; Endoplasmic Reticulum Stress; Heart Ventricles; Male; Myocardial Reperfusion Injury; Myocytes, Cardiac; Rats; Rats, Sprague-Dawley; Taurochenodeoxycholic Acid; Transcription Factor CHOP; Ventricular Function

The aim of this study is to determine the link between oocyte cryopreservation and endoplasmic reticulum (ER) stress; whether ER stress inhibition improves the efficiency of oocyte vitrification is also explored. Oocytes from mice were exposure to tauroursodeoxycholic acid (TUDCA, an ER stress inhibitor) or TM (tunicamycin, an ER stress inducer) with or without vitrification. The expressions of X-box binding protein-1 (XBP-1) protein and caspase-12 protein, viability of vitrified-warmed oocytes, and their subsequent embryo competence were measured. The levels of XBP-1 protein and caspase-12 protein expression in vitrified-warmed oocytes were significantly higher than those of fresh control oocytes. TUDCA improved the viability of vitrified-warmed oocytes and their subsequent embryo competence. Mouse oocyte cryopreservation is associated with ER stress, and ER stress inhibition improves the efficiency of oocyte vitrification.

Topics: Animals; Caspase 12; Cell Survival; Cryopreservation; DNA-Binding Proteins; Endoplasmic Reticulum Stress; Female; Mice; Mice, Inbred ICR; Oocytes; Regulatory Factor X Transcription Factors; Taurochenodeoxycholic Acid; Transcription Factors; Tunicamycin; Vitrification; X-Box Binding Protein 1

Endoplasmic reticulum (ER) stress was previously reported to contribute to neurogenic hypertension while neuronal angiotensin-converting enzyme type 2 (ACE2) overexpression blunts the disease. To assess which brain regions are important for ACE2 beneficial effects and the contribution of ER stress to neurogenic hypertension, we first used transgenic mice harboring a floxed neuronal hACE2 transgene (SL) and tested the impact of hACE2 knockdown in the subfornical organ (SFO) and paraventricular nucleus (PVN) on deoxycorticosterone acetate (DOCA)-salt hypertension. SL and nontransgenic (NT) mice underwent DOCA-salt or sham treatment while infected with an adenoassociated virus (AAV) encoding Cre recombinase (AAV-Cre) or a control virus (AAV-green fluorescent protein) to the SFO or PVN. DOCA-salt-induced hypertension was reduced in SL mice, with hACE2 overexpression in the brain. This reduction was only partially blunted by knockdown of hACE2 in the SFO or PVN, suggesting that both regions are involved but not essential for ACE2 regulation of blood pressure (BP). DOCA-salt treatment did not increase the protein levels of ER stress and autophagy markers in NT mice, despite a significant increase in BP. In addition, these markers were not affected by hACE2 overexpression in the brain, despite a significant reduction of hypertension in SL mice. To further assess the role of ER stress in neurogenic hypertension, NT mice were infused intracerebroventricularlly with tauroursodeoxycholic acid (TUDCA), an ER stress inhibitor, during DOCA-salt treatment. However, TUDCA infusion failed to blunt the development of hypertension in NT mice. Our data suggest that brain ER stress does not contribute to DOCA-salt hypertension and that ACE2 blunts neurogenic hypertension independently of ER stress.

Topics: Angiotensin-Converting Enzyme 2; Animals; Biomarkers; Blood Pressure; Brain; Desoxycorticosterone Acetate; Disease Models, Animal; Endoplasmic Reticulum; Endoplasmic Reticulum Stress; Gene Knockdown Techniques; Humans; Hypertension; Infusions, Intraventricular; Mice, Inbred C57BL; Mice, Transgenic; Paraventricular Hypothalamic Nucleus; Peptidyl-Dipeptidase A; Sodium Chloride, Dietary; Subfornical Organ; Taurochenodeoxycholic Acid; Time Factors; Up-Regulation

Tauroursodeoxycholic acid (TUDCA) a bile salt and chemical chaperone reduces stress-induced aggregation of proteins; activates PERK [PKR (RNA-dependent protein kinase)-like ER (endoplasmic reticulum) kinase] or EIF2AK3, one of the hall marks of ER stress induced unfolded protein response (UPR) in human hepatoblastoma HepG2 cells; prevents heat and dithiothreitol (DTT) induced aggregation of BSA (bovine serum albumin), and reduces ANS (1-anilino-naphthalene-8-sulfonate) bound BSA fluorescence in vitro. TUDCA inactivates heat treated, but not the native EcoR1 enzyme, and reduces heat-induced aggregation and activity of COX-1 (cyclooxygenase enzyme-1) in vitro. These findings suggest that TUDCA binds to the hydrophobic regions of proteins and prevents their subsequent aggregation. This may stabilize unfolded proteins that can mount UPR or facilitate their degradation through cellular degradation pathways.

Topics: Cyclooxygenase 1; Deoxyribonuclease EcoRI; Dithioerythritol; eIF-2 Kinase; Endoplasmic Reticulum Stress; Enzyme Activation; Hep G2 Cells; Hot Temperature; Humans; Protein Aggregates; Serum Albumin, Bovine; Taurochenodeoxycholic Acid; Unfolded Protein Response

The role of the unfolded protein response (UPR) in tissue homeostasis remains largely unknown. Here we find that loss of Mst1/2, the mammalian Hippo orthologues, or their regulator WW45, leads to a remarkably enlarged endoplasmic reticulum (ER) size-associated UPR. Intriguingly, attenuation of the UPR by tauroursodeoxycholic acid (TUDCA) diminishes Mst1/2 mutant-driven liver overgrowth and tumorigenesis by promoting nuclear exit and degradation of Hippo downstream effector Yap. Yap is required for UPR activity and ER expansion to alleviate ER stress. During the adaptive stage of the UPR, PERK kinase-eIF2α axis activates Yap, while prolonged ER stress-induced Hippo signalling triggers assembly of the GADD34/PP1 complex in a negative feedback loop to inhibit Yap and promote apoptosis. Significantly, the deregulation of UPR signals associated with Yap activation is found in a substantial fraction of human hepatocellular carcinoma (HCC). Thus, we conclude Yap integrates Hippo and UPR signalling to control liver size and tumorigenesis.

Topics: Activating Transcription Factor 6; Adaptor Proteins, Signal Transducing; Animals; Blotting, Western; Carcinogenesis; Cell Cycle Proteins; Endoplasmic Reticulum; Hep G2 Cells; Hepatocyte Growth Factor; Hepatocytes; Humans; Liver; Liver Neoplasms; Mice, Inbred C57BL; Mice, Knockout; Models, Biological; Molecular Sequence Data; Mutation; Organ Size; Phosphoproteins; Poly(ADP-ribose) Polymerases; Protein Serine-Threonine Kinases; Proto-Oncogene Proteins; Serine-Threonine Kinase 3; Signal Transduction; Taurochenodeoxycholic Acid; Transcription, Genetic; Unfolded Protein Response; YAP-Signaling Proteins

Ectopic ossification occurs in a wide range of common and genetic diseases, but its molecular mechanisms and effective therapeutic targets remain to be clarified. The aim of the study is to investigate whether endoplasmic reticulum (ER) stress is involved in ectopic ossification and ER stress inhibitor tauroursodeoxycholic acid (TUDCA) has potential to treat the pathological conditions. In this study, inorganic phosphate (Pi)-induced NIH3T3 fibroblasts induced osteogenesis and mineralization was used as an in vitro model for ectopic ossification. Various concentrations of TUDCA (0.1, 1, 5, 10 μM) were added during osteogenic induction. Osteoblast differentiation and minerlization were determined by RT-qPCR, alkaline phosphatase (ALP) activity assay, Alizarin Red-S (AR-S) staining, and calcium deposition. ER stress signalling components were detected by Western-blot analysis. We found ER stress was activated by inorganic phosphate in NIH3T3 cells. During osteogenic induction, TUDCA inhibited NIH3T3 cells ALP activity and mineral nodule formation. In addition, TUDCA caused decreased expression of osteoblastic markers Runx2, Col1a1, ALP, OCN. Mechanistically, TUDCA inhibited the ER stress response PERK-eIF2α-ATF4 pathway during osteogenesis. In conclusion, TUDCA could inhibit fibroblasts mineralization via supressing the ER stress response PERK-eIF2α-ATF4 pathway, and has potential pharmacologic and therapeutic applications for treating ectopic ossification associated diseases.

Topics: Activating Transcription Factor 4; Animals; Calcification, Physiologic; Calcium; Cell Differentiation; eIF-2 Kinase; Endoplasmic Reticulum Stress; Mice; NIH 3T3 Cells; Osteoblasts; Phosphates; Protein Serine-Threonine Kinases; Signal Transduction; Taurochenodeoxycholic Acid

Curcumin is a natural polyphenolic compound in Curcuma longa with beneficial effects on neuronal protection. This study aims to investigate the action of curcumin in the hippocampus subjected to glutamate neurotoxicity. Glutamate stimulation induced reactive oxygen species (ROS), endoplasmic reticulum stress (ER stress) and TXNIP/NLRP3 inflammasome activation, leading to damage in the hippocampus. Curcumin treatment in the hippocampus or SH-SY5Y cells inhibited IRE1α and PERK phosphorylation with suppression of intracellular ROS production. Curcumin increased AMPK activity and knockdown of AMPKα with specific siRNA abrogated its inhibitory effects on IRE1α and PERK phosphorylation, indicating that AMPK activity was essential for the suppression of ER stress. As a result, curcumin reduced TXNIP expression and inhibited NLRP3 inflammasome activation by downregulation of NLRP3 and cleaved caspase-1 induction, and thus reduced IL-1β secretion. Specific fluorescent probe and flow cytometry analysis showed that curcumin prevented mitochondrial malfunction and protected cell survival from glutamate neurotoxicity. Moreover, oral administration of curcumin reduced brain infarct volume and attenuated neuronal damage in rats subjected to middle cerebral artery occlusion. Immunohistochemistry showed that curcumin inhibited p-IRE1α, p-PERK and NLRP3 expression in hippocampus CA1 region. Together, these results showed that curcumin attenuated glutamate neurotoxicity by inhibiting ER stress-associated TXNIP/NLRP3 inflammasome activation via the regulation of AMPK, and thereby protected the hippocampus from ischemic insult.

Topics: AMP-Activated Protein Kinases; Animals; Behavior, Animal; Carrier Proteins; Cell Line, Tumor; Curcumin; Endoplasmic Reticulum Stress; Glutamic Acid; Hippocampus; Humans; Infarction, Middle Cerebral Artery; Inflammasomes; Interleukin-1beta; Interleukin-6; Male; Membrane Potential, Mitochondrial; Mice, Inbred ICR; Motor Activity; Neuroprotective Agents; NLR Family, Pyrin Domain-Containing 3 Protein; Rats, Sprague-Dawley; Reactive Oxygen Species; Taurochenodeoxycholic Acid; Thioredoxins

Renewal and elimination of the aged photoreceptor outer segment (POS) by RPE cells is a daily rhythmic process that is important for long-term vision. Phagocytic dysfunction results in photoreceptor cell death. Tauroursodeoxycholic acid (TUDCA), an endogenous bile acid, is known to show neuroprotective effects in stroke, neurological diseases, and retinal degeneration models. In this study, we investigated the effects of TUDCA on retinal phagocytosis.. We used pHrodo-succinimidyl ester (SE), a pH-sensitive fluorescent dye, to label the POS for monitoring phagocytosis. After ingestion, the intensity of pHrodo fluorescence increases because of the pH changes inside the liposome. An RPE cell line, ARPE-19, and primary human RPE cells were used to investigate the hydrogen peroxide (H2O2)-induced disruption of phagocytosis in the pH-sensitive fluorescence POS phagocytosis assay. Additionally, we examined whether TUDCA could promote phagocytic function.. The intensity of pHrodo light emission increased in a time-dependent manner. Tauroursodeoxycholic acid enhanced phagocytosis of POS and protected against H2O2-induced phagocytic dysfunction. It also promoted phagocytic function via activation of Mer tyrosine kinase receptor (MerTK), which is known to have a key role in the physiological renewal of POS.. These results suggest that TUDCA activates MerTK, which is important for phagocytosis of POS. Tauroursodeoxycholic acid may represent a new therapeutic option for the treatment of retinal diseases.

Topics: Aged; Animals; Blotting, Western; c-Mer Tyrosine Kinase; Cell Death; Cells, Cultured; Humans; Phagocytosis; Proto-Oncogene Proteins; Receptor Protein-Tyrosine Kinases; Retinal Photoreceptor Cell Outer Segment; Retinal Pigment Epithelium; Swine; Taurochenodeoxycholic Acid

To investigate whether tauroursodeoxycholic acid (TUDCA) could attenuate contrast media (CM)-induced renal tubular cell apoptosis by inhibiting endoplasmic reticulum stress (ERS), we exposed HK-2 cells to increasing doses of meglumine diatrizoate (20, 40, and 80 mg I/mL) for 2 to 16 hours, with/without TUDCA preconditioning for 24 hours. Cell viability test, Hoechst 33258 staining, and flow cytometry were used to detect meglumine diatrizoate-induced cell apoptosis, while real-time polymerase chain reaction and Western blot analysis were used to measure the expressions of ERS markers of glucose-regulated protein 78 (GRP78), activating transcription factor 4 (ATF4), and the apoptosis-related marker of caspase 12. Cell apoptosis and messenger RNA (mRNA) expression of GRP78 (P = .005), ATF4 (P = .01), and caspase 12 (P = .001) were significantly higher in the CM 4 hours group than the control as well as the protein expressions. The TUDCA preconditioning reduced the mRNA expression of GRP78, ATF4, and caspase 12 in the CM 4 hours groups (P = .009, .019, and .003, respectively) as well as the protein expression. In conclusion, TUDCA could protect renal tubular cells from meglumine diatrizoate-induced apoptosis by inhibiting ERS.

Topics: Activating Transcription Factor 4; Apoptosis; Caspase 12; Cell Line; Contrast Media; Cytoprotection; Diatrizoate Meglumine; Dose-Response Relationship, Drug; Endoplasmic Reticulum; Endoplasmic Reticulum Chaperone BiP; Endoplasmic Reticulum Stress; Epithelial Cells; Heat-Shock Proteins; Humans; Kidney Tubules, Proximal; Protective Agents; RNA, Messenger; Taurochenodeoxycholic Acid; Time Factors

Two phase-pure solid forms of tauroursodeoxycholic acid (TUDCA) were prepared and characterized by thermal analysis, vibrational spectroscopy, X-ray diffraction, solid-state nuclear magnetic resonance, and morphological analysis. All solid forms can be produced from solvents and also can be obtained by mechanically and non-mechanically activated polymorph conversion. Near-infrared (NIR) spectroscopy, in combination with chemometrical techniques, was used for the quantitative monitoring of the polymorph conversion of TUDCA in milling process and at different storage temperatures. The NIR spectra in the range of 7139-5488 cm(-1) were considered for multivariate analysis. Results demonstrated that the NIR multivariate chemometric model can predict the percentage of crystal and amorphous TUDCA with the correlation coefficient of 0.9998, root mean square error of calibration of 0.740%, root mean square error of prediction of 0.698%, and root mean square error of cross-validation of 1.49%. In the milling process of crystal TUDCA (Form I), a direct transformation from crystal to glass was observed in 4h. Moreover, the impact of different storage temperatures on the stability of amorphous TUDCA was investigated, and the rate of polymorph transformation was found to be accelerated with increasing temperature.

Topics: Calorimetry, Differential Scanning; Drug Compounding; Drug Stability; Drug Storage; Magnetic Resonance Spectroscopy; Powder Diffraction; Spectroscopy, Near-Infrared; Taurochenodeoxycholic Acid; Temperature; Thermogravimetry; X-Ray Diffraction

This study examined the role of endoplasmic reticulum (ER) stress in mediating chronic intermittent hypoxia (IH)-induced neurocognitive deficits. We designed experiments to demonstrate that ER stress is initiated in the hippocampus under chronic IH and determined its role in apoptotic cell death, impaired synaptic structure and plasticity, and memory deficits.. Two weeks of IH disrupted ER fine structure and upregulated ER stress markers, glucose-regulated protein 78, caspase-12, and C/EBP homologous protein, in the hippocampus, which could be suppressed by ER stress inhibitors, tauroursodeoxycholic acid (TUDCA) and 4-phenylbutyric acid. Meanwhile, ER stress induced apoptosis via decreased Bcl-2, promoted reactive oxygen species production, and increased malondialdehyde formation and protein carbonyl, as well as suppressed mitochondrial function. These effects were largely prevented by ER stress inhibitors. On the other hand, suppression of oxidative stress could reduce ER stress. In addition, the length of the synaptic active zone and number of mature spines were reduced by IH. Long-term recognition memory and spatial memory were also impaired, which was accompanied by reduced long-term potentiation in the Schaffer collateral pathway. These effects were prevented by coadministration of the TUDCA.. These results show that ER stress plays a critical role in underlying memory deficits in obstructive sleep apnea (OSA)-associated IH. Attenuators of ER stress may serve as novel adjunct therapeutic agents for ameliorating OSA-induced neurocognitive impairment.

Topics: Animals; Caspase 3; Endoplasmic Reticulum Stress; Hippocampus; Hypoxia; Male; Memory; Memory, Long-Term; Mice, Inbred C57BL; Mitochondria; Neuronal Plasticity; Neurons; Phenylbutyrates; Proto-Oncogene Proteins c-bcl-2; Reactive Oxygen Species; Spine; Taurochenodeoxycholic Acid

Pachymic acid (PA) is a purified triterpene extracted from medicinal fungus Poria cocos. In this paper, we investigated the anticancer effect of PA on human chemotherapy resistant pancreatic cancer. PA triggered apoptosis in gemcitabine-resistant pancreatic cancer cells PANC-1 and MIA PaCa-2. Comparative gene expression array analysis demonstrated that endoplasmic reticulum (ER) stress was induced by PA through activation of heat shock response and unfolded protein response related genes. Induced ER stress was confirmed by increasing expression of XBP-1s, ATF4, Hsp70, CHOP and phospho-eIF2α. Moreover, ER stress inhibitor tauroursodeoxycholic acid (TUDCA) blocked PA induced apoptosis. In addition, 25 mg kg-1 of PA significantly suppressed MIA PaCa-2 tumor growth in vivo without toxicity, which correlated with induction of apoptosis and expression of ER stress related proteins in tumor tissues. Taken together, growth inhibition and induction of apoptosis by PA in gemcitabine-resistant pancreatic cancer cells were associated with ER stress activation both in vitro and in vivo. PA may be potentially exploited for the use in treatment of chemotherapy resistant pancreatic cancer.

Topics: Activating Transcription Factor 4; Animals; Antineoplastic Agents; Apoptosis; Cell Line, Tumor; Deoxycytidine; DNA-Binding Proteins; Drug Resistance, Neoplasm; Endoplasmic Reticulum Stress; Eukaryotic Initiation Factor-2; Female; Gemcitabine; Gene Expression Profiling; Gene Expression Regulation, Neoplastic; HSP70 Heat-Shock Proteins; Humans; Mice; Mice, Nude; Pancreas; Pancreatic Neoplasms; Poria; Regulatory Factor X Transcription Factors; Signal Transduction; Taurochenodeoxycholic Acid; Transcription Factor CHOP; Transcription Factors; Triterpenes; Unfolded Protein Response; X-Box Binding Protein 1; Xenograft Model Antitumor Assays

Prion diseases are fatal neurodegenerative disorders associated with the conversion of cellular prion protein (PrPC) into its aberrant infectious form (PrPSc). There is no treatment available for these diseases. The bile acids tauroursodeoxycholic acid(TUDCA) and ursodeoxycholic acid (UDCA) have been recently shown to be neuroprotective in other protein misfolding disease models, including Parkinson’s, Huntington’s and Alzheimer’s diseases, and also in humans with amyotrophic lateral sclerosis.Here, we studied the therapeutic efficacy of these compounds in prion disease. We demonstrated that TUDCA and UDCA substantially reduced PrP conversion in cell-free aggregation assays, as well as in chronically and acutely infected cell cultures. This effect was mediated through reduction of PrPSc seeding ability, rather than an effect on PrPC. We also demonstrated the ability of TUDCA and UDCA to reduce neuronal loss in prion-infected cerebellar slice cultures. UDCA treatment reduced astrocytosis and prolonged survival in RML prion-infected mice. Interestingly, these effects were limited to the males, implying a gender-specific difference in drug metabolism. Beyond effects on PrPSc, we found that levels of phosphorylated eIF2 were increased at early time points, with correlated reductions in postsynaptic density protein 95. As demonstrated for other neurodegenerative diseases, we now show that TUDCA and UDCA may have a therapeutic role in prion diseases, with effects on both prion conversion and neuroprotection. Our findings, together with the fact that these natural compounds are orally bioavailable, permeable to the blood-brain barrier, and U.S. Food and Drug Administration-approved for use in humans, make these compounds promising alternatives for the treatment of prion diseases.. Prion diseases are fatal neurodegenerative diseases that are transmissible to humans and other mammals. There are no disease-modifying therapies available, despite decades of research. Treatment targets have included inhibition of protein accumulation,clearance of toxic aggregates, and prevention of downstream neurodegeneration. No one target may be sufficient; rather, compounds which have a multimodal mechanism, acting on different targets, would be ideal. TUDCA and UDCA are bile acids that may fulfill this dual role. Previous studies have demonstrated their neuroprotective effects in several neurodegenerative disease models, and we now demonstrate that this effect occurs in prion disease, with an added mechanistic target of upstream prion seeding. Importantly, these are natural compounds which are orally bioavailable, permeable to the blood-brain barrier, and U.S.Food and Drug Administration-approved for use in humans with primary biliary cirrhosis. They have recently been proven efficacious in human amyotrophic lateral sclerosis. Therefore, these compounds are promising options for the treatment of prion diseases.

Topics: Animals; Bile Acids and Salts; Cell Death; Cell Survival; Female; Humans; Male; Mice; Mice, Inbred C57BL; Neurons; Prion Diseases; PrPC Proteins; PrPSc Proteins; Species Specificity; Taurochenodeoxycholic Acid; Ursodeoxycholic Acid

Here we study links between aminoglycoside-induced mistranslation, protein misfolding and neuropathy. We demonstrate that aminoglycosides induce misreading in mammalian cells and assess endoplasmic reticulum (ER) stress and unfolded protein response (UPR) pathways. Genome-wide transcriptome and proteome analyses revealed upregulation of genes related to protein folding and degradation. Quantitative PCR confirmed induction of UPR markers including C/EBP homologous protein, glucose-regulated protein 94, binding immunoglobulin protein and X-box binding protein-1 (XBP1) mRNA splicing, which is crucial for UPR activation. We studied the effect of a compromised UPR on aminoglycoside ototoxicity in haploinsufficient XBP1 (XBP1(+/-)) mice. Intra-tympanic aminoglycoside treatment caused high-frequency hearing loss in XBP1(+/-) mice but not in wild-type littermates. Densities of spiral ganglion cells and synaptic ribbons were decreased in gentamicin-treated XBP1(+/-) mice, while sensory cells were preserved. Co-injection of the chemical chaperone tauroursodeoxycholic acid attenuated hearing loss. These results suggest that aminoglycoside-induced ER stress and cell death in spiral ganglion neurons is mitigated by XBP1, masking aminoglycoside neurotoxicity at the organismal level.

Topics: Animals; CCAAT-Enhancer-Binding Proteins; Cell Line; DNA-Binding Proteins; Endoplasmic Reticulum; Endoplasmic Reticulum Stress; Female; Gentamicins; Hair Cells, Auditory; Hearing Loss, High-Frequency; HEK293 Cells; Humans; Male; Membrane Glycoproteins; Mice; Mice, Inbred CBA; Neurons; Protein Biosynthesis; Protein Folding; Proteostasis Deficiencies; Regulatory Factor X Transcription Factors; RNA Splicing; Spiral Ganglion; Taurochenodeoxycholic Acid; Transcription Factors; Unfolded Protein Response; X-Box Binding Protein 1

This study tested the hypothesis whether endoplasmic reticulum (ER) stress/C/EBP homologous protein (CHOP) signaling is linked with coxsackievirus B3 (CVB3)-induced acute viral myocarditis (AVMC) in vivo.. AVMC was induced by intraperitoneal injection of 1000 tissue culture infectious dose (TCID50) of CVB3 virus in mice. In AVMC mouse hearts (n=11), ER stress and CHOP were significantly activated, and were linked to the induction of proapoptotic signaling including reduction of Bcl-2, activation of Bax and caspase 3, compared with the controls (n=10), whereas these could be markedly blocked by ER stress inhibitor tauroursodeoxycholic acid administration (n=11). Moreover, chemical inhibition of ER stress significantly attenuated cardiomyocytes apoptosis, and prevented cardiac troponin I elevation, ameliorated cardiac dysfunction assessed by both hemodynamic and echocardiographic analysis, reduced viral replication, and increased survival rate after CVB3 inoculation. We further discovered that genetic ablation of CHOP (n=10) suppressed cardiac Bcl-2/Bax ratio reduction and caspase 3 activation, and prevented cardiomyotes apoptosis in vivo, compared with wild-type receiving CVB3 inoculation (n=10). Strikingly, CHOP deficiency exhibited dramatic protective effects on cardiac damage, cardiac dysfunction, viral replication, and promoted survival in CVB3-caused AVMC.. Our data imply the involvement of ER stress/CHOP signaling in CVB3-induced AVMC via proapoptotic pathways, and provide a novel strategy for AVMC treatment.

Topics: Animals; Antiviral Agents; Apoptosis; bcl-2-Associated X Protein; Caspase 3; Coxsackievirus Infections; Disease Models, Animal; Endoplasmic Reticulum; Endoplasmic Reticulum Stress; Enterovirus B, Human; Male; Mice, Inbred C57BL; Mice, Knockout; Myocarditis; Myocytes, Cardiac; Proto-Oncogene Proteins c-bcl-2; Signal Transduction; Taurochenodeoxycholic Acid; Transcription Factor CHOP; Virus Replication

The purpose of this study was to evaluate the role of CCAAT/enhancer-binding protein homologous protein (CHOP), an important transcription factor that regulates the inflammatory reaction during the endoplasmic reticulum (ER) stress response, in the development of pulmonary fibrosis induced by bleomycin (BLM) in mice. An intratracheal injection of BLM transiently increased the expression of CHOP mRNA and protein in an early phase (days 1 and 3) in mice lungs. BLM-induced pulmonary fibrosis was significantly attenuated in Chop gene deficient (Chop KO) mice, compared with wild-type (WT) mice. Furthermore, the inflammatory reactions evaluated by protein concentration, the total number of leucocytes and neutrophils in the bronchoalveolar lavage fluid (BALF), the mRNA expression of interleukin 1b and caspase 11, and the apoptotic cell death were suppressed in Chop KO mice compared with those in WT mice. In addition, administration of tauroursodeoxycholic acid (TUDCA), a pharmacological agent that can inhibit CHOP expression, inhibited the BLM-induced pulmonary fibrosis and inflammation, and the increase in Chop mRNA expression in WT mice in a dose-dependent manner. These results suggest that the ER stress-induced transcription factor, CHOP, at least in part, plays an important role in the development of BLM-induced pulmonary fibrosis in mice, and that the inhibition of CHOP expression by a pharmacological agent, such as TUDCA, may be a promising strategy for the prevention of pulmonary fibrosis.

Topics: Animals; Apoptosis; Bleomycin; Disease Models, Animal; Endoplasmic Reticulum Stress; Gene Expression; Lung; Mice; Mice, Inbred C57BL; Mice, Knockout; Pulmonary Fibrosis; RNA, Messenger; Taurochenodeoxycholic Acid; Transcription Factor CHOP

Ursodeoxycholic acid, which in vivo is rapidly converted into its taurine conjugate, is frequently used for the treatment of cholestatic liver disease. Apart from its choleretic effects, tauroursodeoxycholate (TUDC) can protect hepatocytes from bile acid-induced apoptosis, but the mechanisms underlying its anti-apoptotic effects are poorly understood.. These mechanisms were investigated in perfused rat liver and isolated rat hepatocytes.. It was found that TUDC inhibited the glycochenodeoxycholate (GCDC)-induced activation of the CD95 death receptor at the level of association between CD95 and the epidermal growth factor receptor. This was due to a rapid TUDC-induced β1-integrin-dependent cyclic AMP (cAMP) signal with induction of the dual specificity mitogen-activated protein (MAP) kinase phosphatase 1 (MKP-1), which prevented GCDC-induced phosphorylation of mitogen-activated protein kinase kinase 4 (MKK4) and c-jun-NH2-terminal kinase (JNK) activation. Furthermore, TUDC induced a protein kinase A (PKA)-mediated serine/threonine phosphorylation of the CD95, which was recently identified as an internalization signal for CD95. Furthermore, TUDC inhibited GCDC-induced CD95 targeting to the plasma membrane in a β1-integrin-and PKA-dependent manner. In line with this, the β1-integrin siRNA knockdown in sodium taurocholate cotransporting polypeptide (Ntcp)-transfected HepG2 cells abolished the protective effect of TUDC against GCDC-induced apoptosis.. TUDC exerts its anti-apoptotic effect via a β1-integrin-mediated formation of cAMP, which prevents CD95 activation by hydrophobic bile acids at the levels of JNK activation and CD95 serine/threonine phosphorylation.

Topics: Animals; Apoptosis; Cyclic AMP; Cyclic AMP-Dependent Protein Kinases; Dual Specificity Phosphatase 1; ErbB Receptors; fas Receptor; Gene Expression Regulation; Glycochenodeoxycholic Acid; Hepatocytes; Integrin beta1; JNK Mitogen-Activated Protein Kinases; Liver; Male; MAP Kinase Kinase 4; Organ Culture Techniques; Organic Anion Transporters, Sodium-Dependent; Phosphorylation; Primary Cell Culture; Pulsatile Flow; Rats; Rats, Wistar; Signal Transduction; Symporters; Taurochenodeoxycholic Acid

We previously demonstrated that tauroursodeoxycholic acid (TUDCA) improved the developmental competence of mouse embryos by attenuating endoplasmic reticulum (ER) stress-induced apoptosis during preimplantation development. Here, we present a follow-up study examining whether TUDCA enhances the implantation and live-birth rate of mouse embryos. Mouse 2-cell embryos were collected by oviduct flushing and cultured in the presence or absence of 50 μM TUDCA. After culture (52 h), blastocysts were transferred to 2.5-day pseudopregnant foster mothers. It was found that the rates of pregnancy and implantation as well as the number of live pups per surrogate mouse were significantly higher in the TUDCA-treated group compared to the control group, but there was no significant difference in the mean weights of the pups or placentae. Thus, we report for the first time that TUDCA supplementation of the embryo culture medium increased the implantation and livebirth rates of transferred mouse embryos.

Topics: Animals; Birth Weight; Blastocyst; Blastomeres; Crosses, Genetic; Ectogenesis; Embryo Culture Techniques; Embryo Transfer; Female; Fertility Agents, Female; Litter Size; Live Birth; Male; Mice, Inbred C57BL; Mice, Inbred DBA; Mice, Inbred ICR; Osmolar Concentration; Placentation; Pregnancy; Reproductive Techniques, Assisted; Taurochenodeoxycholic Acid

To determine the effect of advanced glycation end-products (AGEs) on neurite regeneration, and also to determine the regenerative effects of different neurotrophic factors (NTFs) on rat retinal explants, the retinas of SD rats were cultured in three-dimensional collagen gels and incubated in 6 types of media: (1) serum-free control culture media; (2) 100 μg/mL AGEs-BSA media; (3) AGEs-BSA + 100 ng/mL neurotrophin-4 (NT-4) media; (4) AGEs-BSA + 100 ng/mL hepatocyte growth factor media; (5) AGEs-BSA + 100 ng/mL glial cell line-derived neurotrophic factor media; or (6) AGEs-BSA + 100 µM tauroursodeoxycholic acid media. After 7 days, the number of regenerating neurites was counted. The explants were immunostained for nuclear factor-κB (NF-κB) and specificity protein 1 (SP1). Statistical analyses were performed by one-way ANOVA. In retinas incubated with AGEs, the numbers of neurites were fewer than in control. All of the NTFs increased the number of neurites, and the increase was more significant in the NT-4 group. The number of NF-κB and SP1 immunopositive cells was higher in retinas exposed to AGEs than in control. All of the NTFs decreased the number of NF-κB immunopositive cells but did not significantly affect SP1 expression. These results demonstrate the potential of the NTFs as axoprotectants in AGEs exposed retinal neurons.

Topics: Animals; Glial Cell Line-Derived Neurotrophic Factor; Glycation End Products, Advanced; Hepatocyte Growth Factor; Nerve Growth Factors; Nerve Regeneration; Neurites; NF-kappa B; Rats; Retina; Sp1 Transcription Factor; Taurochenodeoxycholic Acid

Proinflammatory cytokines contribute to beta cell damage in type 1 diabetes in part through activation of endoplasmic reticulum (ER) stress. In rat beta cells, cytokine-induced ER stress involves NO production and consequent inhibition of the ER Ca(2+) transporting ATPase sarco/endoplasmic reticulum Ca(2+) pump 2 (SERCA2B). However, the mechanisms by which cytokines induce ER stress and apoptosis in mouse and human pancreatic beta cells remain unclear. The purpose of this study is to elucidate the role of ER stress on cytokine-induced beta cell apoptosis in these three species and thus solve ongoing controversies in the field.. Rat and mouse insulin-producing cells, human pancreatic islets and human EndoC-βH1 cells were exposed to the cytokines IL-1β, TNF-α and IFN-γ, with or without NO inhibition. A global comparison of cytokine-modulated gene expression in human, mouse and rat beta cells was also performed. The chemical chaperone tauroursodeoxycholic acid (TUDCA) and suppression of C/EBP homologous protein (CHOP) were used to assess the role of ER stress in cytokine-induced apoptosis of human beta cells.. NO plays a key role in cytokine-induced ER stress in rat islets, but not in mouse or human islets. Bioinformatics analysis indicated greater similarity between human and mouse than between human and rat global gene expression after cytokine exposure. The chemical chaperone TUDCA and suppression of CHOP or c-Jun N-terminal kinase (JNK) protected human beta cells against cytokine-induced apoptosis.. These observations clarify previous results that were discrepant owing to the use of islets from different species, and confirm that cytokine-induced ER stress contributes to human beta cell death, at least in part via JNK activation.

Topics: Animals; Cell Line; Cell Survival; Cytokines; Endoplasmic Reticulum Stress; Enzyme Inhibitors; Humans; Insulin-Secreting Cells; Interferon-gamma; Interleukin-1beta; Male; Mice; Nitric Oxide Synthase Type II; omega-N-Methylarginine; Rats; Rats, Wistar; Signal Transduction; Taurochenodeoxycholic Acid; Transcription Factor CHOP; Tumor Necrosis Factor-alpha

Nanomaterials are used in diverse fields including food, cosmetic, and medical industries. Titanium dioxide nanoparticles (TiO2-NP) are widely used, but their effects on biological systems and mechanism of toxicity have not been elucidated fully. Here, we report the toxicological mechanism of TiO2-NP in cell organelles. Human bronchial epithelial cells (16HBE14o-) were exposed to 50 and 100 μg/mL TiO2-NP for 24 and 48 h. Our results showed that TiO2-NP induced endoplasmic reticulum (ER) stress in the cells and disrupted the mitochondria-associated endoplasmic reticulum membranes (MAMs) and calcium ion balance, thereby increasing autophagy. In contrast, an inhibitor of ER stress, tauroursodeoxycholic acid (TUDCA), mitigated the cellular toxic response, suggesting that TiO2-NP promoted toxicity via ER stress. This novel mechanism of TiO2-NP toxicity in human bronchial epithelial cells suggests that further exhaustive research on the harmful effects of these nanoparticles in relevant organisms is needed for their safe application.

Topics: Autophagy; Calcium; Cells, Cultured; Endoplasmic Reticulum; Endoplasmic Reticulum Stress; Epithelial Cells; Homeostasis; Humans; Intracellular Membranes; Lung; Mitochondria; Nanoparticles; Reactive Oxygen Species; Taurochenodeoxycholic Acid; Titanium

The main pathogenic events in osteoarthritis (OA) include loss and abnormal remodeling of cartilage extracellular matrix. The present study aimed to evaluate the protective effect of tauroursodeoxycholic acid on chondrocyte apoptosis induced by endoplasmic reticulum (ER) stress. Articular cartilage tissues were collected from 18 patients who underwent total knee arthroplasty and were analyzed histologically. Subsequently, chondrocyte apoptosis was assessed by TUNEL. Quantitative polymerase chain reaction and western blot analysis were employed to evaluate gene and protein expression, respectively, of ER stress markers, including glucose‑regulated protein 78 (GRP78), growth arrest and DNA‑damage‑inducible gene 153 (GADD153) and caspase‑12 along with type II collagen. Chondrocytes obtained from osteoarthritis patients at different stages were cultured in three conditions including: No treatment (CON group), tunicamycin treatment to induce ER stress (ERS group) and tauroursodeoxycholic acid treatment after 4 h of tunicamycin (TDA group); and cell proliferation, apoptosis, function and ER stress level were assessed. Degradation of cartilage resulted in histological damage with more apoptotic cartilage cells observed. Of note, GRP78, GADD153 and caspase‑12 mRNA and protein expression increased gradually from grade I to III cartilage tissue, while type II collagen expression decreased. Tunicamycin induced ER stress, as shown by a high expression of ER stress markers, reduced cell proliferation, increased apoptosis and decreased synthesis of type II collagen. Notably, tauroursodeoxycholic acid treatment resulted in the improvement of tunicamycin‑induced ER stress. These results indicated that ER stress is highly involved in the tunicamycin‑induced apoptosis in chondrocytes, which can be prevented by tauroursodeoxycholic acid.

Topics: Adolescent; Adult; Aged; Caspase 12; Cells, Cultured; Chondrocytes; Endoplasmic Reticulum Chaperone BiP; Endoplasmic Reticulum Stress; Female; Gene Expression Regulation; Heat-Shock Proteins; Humans; Male; Middle Aged; Osteoarthritis; Taurochenodeoxycholic Acid; Transcription Factor CHOP; Tunicamycin

Topics: Amyotrophic Lateral Sclerosis; Animals; Cholagogues and Choleretics; Endoplasmic Reticulum; Humans; Taurochenodeoxycholic Acid; Unfolded Protein Response

Gefitinib and erlotinib are anticancer agents, which inhibit epidermal growth factor receptor (EGFR) tyrosine kinase. Interstitial lung disease (ILD) occurs in patients with non-small cell lung cancer receiving EGFR inhibitors. In the present study, we examined whether gefitinib- and erlotinib-induced lung injury related to ILD through endoplasmic reticulum (ER) stress, which is a causative intracellular mechanism in cytotoxicity caused by various chemicals in adenocarcinomic human alveolar basal epithelial cells. These two EGFR inhibitors increased Parkinson juvenile disease protein 2 and C/EBP homologous protein mRNA expressions, and activated the eukaryotic initiation factor (eIF) 2α/activating transcription factor 4 pathway without protein kinase R-like ER kinase activation in A549 cells. Gefitinib and erlotinib caused neither ER stress nor cell death; however, these agents inhibited cell growth via the reduction of cyclin-D1 expression. Tauroursodeoxycholic acid, which is known to suppress eIF2α phosphorylation, cancelled the effects of EGFR inhibitors on cyclin-D1 expression and cell proliferation in a concentration-dependent manner. The results of an EGFR-silencing study using siRNA showed that gefitinib and erlotinib affected eIF2α phosphorylation and cyclin-D1 expression independent of EGFR inhibition. Therefore, the inhibition of cell growth by these EGFR inhibitors might equate to impairment of the alveolar epithelial cell repair system via eIF2α phosphorylation and reduced cyclin-D1 expression.

Topics: Antineoplastic Agents; Cell Line; Cell Proliferation; Cyclin D1; Endoplasmic Reticulum Stress; ErbB Receptors; Erlotinib Hydrochloride; Eukaryotic Initiation Factor-2; Gefitinib; Humans; Lung Diseases, Interstitial; Phosphorylation; Pulmonary Alveoli; Quinazolines; Signal Transduction; Taurochenodeoxycholic Acid

Hepatocellular carcinoma (HCC) is characterized by the accumulation of unfolded proteins in the endoplasmic reticulum (ER), which activates the unfolded protein response (UPR). However, the role of ER stress in tumor initiation and progression is controversial. To determine the impact of ER stress, we applied tauroursodeoxycholic acid (TUDCA), a bile acid with chaperone properties. The effects of TUDCA were assessed using a diethylnitrosamine-induced mouse HCC model in preventive and therapeutic settings. Cell metabolic activity, proliferation and invasion were investigated in vitro. Tumor progression was assessed in the HepG2 xenograft model. Administration of TUDCA in the preventive setting reduced carcinogen-induced elevation of alanine and aspartate aminotransferase levels, apoptosis of hepatocytes and tumor burden. TUDCA also reduced eukaryotic initiation factor 2α (eIf2α) phosphorylation, C/EBP homologous protein expression and caspase-12 processing. Thus, TUDCA suppresses carcinogen-induced pro-apoptotic UPR. TUDCA alleviated hepatic inflammation by increasing NF-κB inhibitor IκBα. Furthermore, TUDCA altered the invasive phenotype and enhanced metabolic activity but not proliferation in HCC cells. TUDCA administration after tumor development did not alter orthotopic tumor or xenograft growth. Taken together, TUDCA attenuates hepatocarcinogenesis by suppressing carcinogen-induced ER stress-mediated cell death and inflammation without stimulating tumor progression. Therefore, this chemical chaperone could represent a novel chemopreventive agent.

Topics: Animals; Antineoplastic Agents; Apoptosis; Blotting, Western; Carcinogens; Carcinoma, Hepatocellular; Disease Models, Animal; Endoplasmic Reticulum Stress; Hep G2 Cells; Humans; Immunohistochemistry; In Situ Nick-End Labeling; Liver Neoplasms; Male; Mice; Real-Time Polymerase Chain Reaction; Taurochenodeoxycholic Acid; Xenograft Model Antitumor Assays

Retinal ganglion cell degeneration underlies the pathophysiology of diseases affecting the retina and optic nerve. Several studies have previously evidenced the anti-apoptotic properties of the bile constituent, tauroursodeoxycholic acid, in diverse models of photoreceptor degeneration. The aim of this study was to investigate the effects of systemic administration of tauroursodeoxycholic acid on N-methyl-D-aspartate (NMDA)-induced damage in the rat retina using a functional and morphological approach. Tauroursodeoxycholic acid was administered intraperitoneally before and after intravitreal injection of NMDA. Three days after insult, full-field electroretinograms showed reductions in the amplitudes of the positive and negative-scotopic threshold responses, scotopic a- and b-waves and oscillatory potentials. Quantitative morphological evaluation of whole-mount retinas demonstrated a reduction in the density of retinal ganglion cells. Systemic administration of tauroursodeoxycholic acid attenuated the functional impairment induced by NMDA, which correlated with a higher retinal ganglion cell density. Our findings sustain the efficacy of tauroursodeoxycholic acid administration in vivo, suggesting it would be a good candidate for the pharmacological treatment of degenerative diseases coursing with retinal ganglion cell loss.

Topics: Animals; Electroretinography; N-Methylaspartate; Neuroprotective Agents; Optic Nerve; Rats; Rats, Sprague-Dawley; Retina; Retinal Degeneration; Retinal Ganglion Cells; Taurochenodeoxycholic Acid

To investigate the effects of tauroursodeoxycholic acid (TUDCA) and alpha-lipoic-acid (ALA) on the visual response properties of cat retinal ganglion cells (RGCs) in wholemount retinas.. Young adult cats were divided into three groups: control, ALA, and TUDCA. In vitro single-unit extracellular recordings were performed on wholemount retinas to objectively evaluate the visual response properties of RGCs prior and post to antioxidant treatment. The visual responses properties of RGCs, including receptive field size, luminance threshold, and contrast sensitivity, were collected online and analyzed off-line with Axon Pclamp9.. Most of the RF sizes were larger than those plotted prior to the 60 minutes dark adaptation. The luminance threshold was elevated in the control group (no treatment) but reduced post ALA treatment and significantly reduced post TUDCA treatment. The contrast threshold was significantly elevated in the control group (no treatment) and clearly elevated post ALA treatment but effectively sustained post TUCDA treatment.. Retinal neurocircuitry deteriorates in wholemount retinas, resulting in abnormal visual response properties in RGCs. Alpha-lipoic-acid and TUDCA exerted beneficial neuroprotective effects by activating the antioxidant pathway, partially restoring the functionality of retinal neurocircuitry and significantly improving the visual response properties of RGCs. However, TUDCA appears to be more effective than ALA in reducing irradiance thresholds and improving contrast sensitivity.

Topics: Animals; Antioxidants; Cats; Female; In Vitro Techniques; Male; Microelectrodes; Photic Stimulation; Retinal Ganglion Cells; Sensory Thresholds; Taurochenodeoxycholic Acid; Thioctic Acid; Vision, Ocular

In order to investigate the possible involvement of endoplasmic reticulum (ER) stress in the developmental origins of hepatic steatosis associated with undernourishment in utero, we herein employed a fetal undernourishment mouse model by maternal caloric restriction in three cohorts; cohort 1) assessment of hepatic steatosis and the ER stress response at 9 weeks of age (wks) before a high fat diet (HFD), cohort 2) assessment of hepatic steatosis and the ER stress response on a HFD at 17 wks, cohort 3) assessment of hepatic steatosis and the ER stress response at 22 wks on a HFD after the alleviation of ER stress with a chemical chaperone, tauroursodeoxycholic acid (TUDCA), from 17 wks to 22 wks. Undernourishment in utero significantly deteriorated hepatic steatosis and led to the significant integration of the ER stress response on a HFD at 17 wks. The alleviation of ER stress by the TUDCA treatment significantly improved the parameters of hepatic steatosis in pups with undernourishment in utero, but not in those with normal nourishment in utero at 22 wks. These results suggest the pivotal involvement of the integration of ER stress in the developmental origins of hepatic steatosis in association with undernourishment in utero.

Topics: Animals; Cell Count; Diet, High-Fat; Endoplasmic Reticulum Stress; Fatty Liver; Female; Hydroxyproline; Inflammation; Insulin; Lipids; Liver; Macrophages; Malnutrition; Mice, Inbred C57BL; Taurochenodeoxycholic Acid; Transaminases

To explore the mechanism of tauroursodeoxycholic acid (TUDCA) in suppressing apoptosis in pulmonary tissues of intermittent hypoxia (IH) mice model.
. A total of 32 C57 mice were randomly divided into a control group, a TUDCA group, an IH group and an IH+TUDCA group (8 mice per group). The mice were put in specially designed chambers and exposed to IH treatment for 4 weeks. In the chambers, oxygen levels repeatedly decreased from 21% to 10% and recovered from 10% to 21%, lasting for 8 hours in every day. After 4 weeks of IH exposure, the expression levels of caspase-12 and cleaved caspase-3 in pulmonary tissues were detected by Western blot. Meanwhile, the expression levels of glucose regulated protein-78 (GRP78) and CCAAT/enhancer-binding protein homologous protein (CHOP) were quantified by Western blot, immunochemistry and real-time PCR.
. Compared with the control group, the expression levels of caspase-12, cleaved caspase-3, GRP78 and CHOP were increased in the IH group (all P<0.01). TUDCA treatment could reduce these proteins expression (all P<0.05).
. Endoplasmic reticulum stress-mediated apoptosis can be activated in pulmonary tissues after chronic IH exposure, and TUDCA can reduce the cellular apoptosis via suppressing endoplasmic reticulum stress.. 目的：探究牛磺熊去氧胆酸钠(tauroursodeoxycholic acid sodium，TUDCA)在间歇性低氧(intermittent hypoxia，IH)模型小鼠肺组织中抑制细胞凋亡的机制。方法：32只C57小鼠随机分为对照组、TUDCA组、IH组和IH+TUDCA组，每组8只。将C57小鼠放入低氧舱中进行IH处理4周 (氧气浓度从21%下降到10%，再从10%恢复到21%为一个循环，每个循环的时间为90 s)，每天持续8 h。4周IH处理后，Western印迹检测caspase-12和cleaved caspase-3在肺组织中的表达。同时，Western印迹、免疫组织化学和实时定量PCR检测葡萄糖调节蛋白78(glucose regulated protein 78，GRP78) 和CCAAT/增强结合蛋白同源蛋白(CCAAT/enhancer-binding protein homologous protein，CHOP)的表达。结果：与对照组和TUDCA组相比，IH组小鼠肺组织中caspase-12，cleaved caspase-3，GRP78和CHOP表达明显升高(均P<0.01)；而在IH+TUDCA组中，TUDCA能够显著地减少上述蛋白的表达(均P<0.05)。结论：慢性的IH能够导致肺组织中内质网应激介导的细胞凋亡，而TUDCA可以通过抑制内质网应激的激活来降低细胞的凋亡水平。.

Topics: Animals; Apoptosis; Caspase 12; Caspase 3; Disease Models, Animal; Endoplasmic Reticulum Chaperone BiP; Endoplasmic Reticulum Stress; Heat-Shock Proteins; Hypoxia; Lung; Mice; Mice, Inbred C57BL; Real-Time Polymerase Chain Reaction; Taurochenodeoxycholic Acid; Transcription Factor CHOP

To observe the effects of tauroursodeoxycholic acid (TUDCA) on nerve function after acute spinal cord injury (SCI) in rats, observe its effect on neuronal apoptosis and caspase-12 expression levels, and investigate the underlying mechanism.. We used a modified Allen's weight-drop trauma method to establish a rat acute SCI model. The rats were randomly divided into three groups: group A (sham surgery group), group B (DMSO control group) and group C (TUDCA treatment group), with 36 rats in each group. At one minute and at 24 hours after successfully establishing the model, rats in group C received an intraperitoneal injection of TUDCA (200 mg/kg), while rats in group B received an equal amount of DMSO at the same time points. At 24 hours, three days, and five days after injury, a modified Tarlov scoring method and Rivlin's oblique plate test were used to evaluate rat spinal cord nerve function recovery. Animals were sacrificed at 24 hours, three days, and five days after injury. Specimens were obtained from the center of the injury sites; the pathological changes in spinal cord tissue were observed after hematoxylin-eosin (HE) staining; apoptosis was detected using the TUNEL method, and the expression of caspase-12 was measured at the protein level using immunohistochemistry and Western blots.. Group C differed significantly from group B in Tarlov scores and the oblique table test as early as 24 hours after the injury (P < 0.05). The TUNEL assay test results showed that neurons underwent apoptosis after SCI, which peaked at 24 hours. The ratios of apoptotic cells in group C were significantly lower than those in group B at 24 hours, three days, and five days after injury (P < 0.01). The immunohistochemistry and Western blot results showed that the caspase-12 expression levels of group C were lower than those of group B at 24 hours, three days, and five days after injury (P < 0.05).. TUDCA can inhibit the expression of caspase-12 in rat neurons after SCI, reduce cell apoptosis, and exert neuroprotective effects on rat secondary nerve injuries after SCI.

Topics: Acute Disease; Animals; Behavior, Animal; Blotting, Western; Caspase 12; Disease Models, Animal; Immunohistochemistry; In Situ Nick-End Labeling; Male; Motor Activity; Neuroprotective Agents; Rats, Sprague-Dawley; Recovery of Function; Spinal Cord; Spinal Cord Injuries; Taurochenodeoxycholic Acid; Time Factors

Impaired fatty liver regeneration has already been reported in many genetic modification models. However, in diet-induced simple hepatic steatosis, which showed similar phenotype with clinical pathology, whether liver regeneration is impaired or not remains unclear. In this study, we evaluated liver regeneration in mice with diet-induced simple hepatic steatosis, and focused on excess lipid accumulation occurring during liver regeneration.. Mice were fed high fat diet (HFD) or control diet for 9-10 weeks. We analyzed intrahepatic lipid accumulation, DNA replication, and various signaling pathways including cell proliferation and ER stress during liver regeneration after partial hepatectomy. In addition, some of mice were pretreated with tauroursodeoxycholic acid (TUDCA), a chemical chaperone which alleviates ER stress, and then we estimated TUDCA effects on liver regeneration.. The peak of hepatocyte BrdU incorporation, the expression of proliferation cell nuclear antigen (PCNA) protein, and the expressions of cell cycle-related genes were observed in delayed time in HFD mice. The expression of phosphorylated Erk1/2 was also delayed in HFD mice. The amounts of liver triglyceride were at least twofold higher in HFD mice at each time point. Intrahepatic palmitic acid was increased especially in HFD mice. ER stress induced during liver regeneration was significantly higher in HFD mice. In HFD mice, pretreatment with TUDCA reduced ER stress and resulted in improvement of delayed liver regeneration.. In simple hepatic steatosis, lipid overloading occurring during liver regeneration might be caused ER stress and results in delayed hepatocyte DNA replication.

Topics: Animals; Cell Proliferation; Cholagogues and Choleretics; Cyclin A2; Cyclin B1; Cyclin D1; Cyclins; Diet, High-Fat; DNA Replication; DNA-Binding Proteins; eIF-2 Kinase; Endoplasmic Reticulum; Endoplasmic Reticulum Chaperone BiP; Fatty Liver; Forkhead Box Protein M1; Forkhead Transcription Factors; Gene Expression; Heat-Shock Proteins; Hepatectomy; Hepatocytes; Liver Regeneration; Male; MAP Kinase Signaling System; Mice; Mice, Inbred C57BL; Organ Size; Phosphorylation; Proliferating Cell Nuclear Antigen; Proto-Oncogene Proteins c-akt; Regulatory Factor X Transcription Factors; RNA, Messenger; Stress, Physiological; Taurochenodeoxycholic Acid; Time Factors; Transcription Factors; Unfolded Protein Response

Our objective was to investigate the role of bile acids in hepatic steatosis reduction after vertical sleeve gastrectomy (VSG).. High fat diet (HFD)-induced obese C57Bl/6 mice were randomized to VSG, Sham operation (Sham), Sham operation with pair feeding to VSG (Sham-PF), or nonsurgical controls (Naïve). All mice were on HFD until sacrifice. Mice were observed postsurgery and data for body weight, body composition, metabolic parameters, serum bile acid level and composition were collected. Further hepatic gene expression by mRNA-seq and RT-PCR analysis was assessed.. VSG and Sham-PF mice lost equal weight postsurgery while VSG mice had the lowest hepatic triglyceride content at sacrifice. The VSG mice had elevated serum bile acid levels that positively correlated with maximal weight loss. Serum bile composition in the VSG group had increased cholic and tauroursodeoxycholic acid. These bile acid composition changes in VSG mice explained observed downregulation of hepatic lipogenic and bile acid synthetic genes.. VSG in obese mice results in greater hepatic steatosis reduction than seen with caloric restriction alone. VSG surgery increases serum bile acids that correlate with weight lost postsurgery and changes serum bile composition that could explain suppression of hepatic genes responsible for lipogenesis.

Topics: Animals; Bile Acids and Salts; Caloric Restriction; Cholic Acid; Diet, High-Fat; Down-Regulation; Fatty Liver; Gastroplasty; Gene Expression Profiling; Gene Expression Regulation; Lipogenesis; Liver; Male; Mice; Mice, Inbred C57BL; Non-alcoholic Fatty Liver Disease; Obesity; Postprandial Period; Random Allocation; Taurochenodeoxycholic Acid; Triglycerides; Up-Regulation; Weight Loss

The aim of this study is to examine whether the increased expression of phosphorylated c-Jun (p-c-Jun) and phosphorylated c-Jun N-terminal kinase (p-JNK) are significantly associated with neuronal cell death in diabetic rat retinas and retinas exposed to high glucose. Retinas isolated from six adult male Sprague-Dawley rats and six streptozotocin-induced diabetic rats (DM) were cultured in serum-free medium. The explants from non-diabetic controls were cultured in normal-glucose (N) or high-glucose (HG) medium. Furthermore, neurotrophin-4 (NT-4) and Taurine-conjugated ursodeoxycholic acid (TUDCA) were incubated in HG medium. After 7 days, the numbers of regenerating neurites were counted per explant. After counting, the explants were fixed, cryosectioned, and stained by TUNEL, and also immunostained for p-c-Jun and p-JNK. The numbers of TUNEL-positive, p-c-Jun- and p-JNK-immunopositive cells in the GCL were significantly higher and the numbers of regenerating neurites were significantly lower in the HG and the DM groups than in the N groups. In the HG groups supplemented with NT-4 and TUDCA, the numbers of TUNEL-positive, p-c-Jun- and p-JNK-immunopositive cells were significantly lower and the numbers of neurites were significantly higher than in the HG group without NT-4 and TUDCA. Increased expression of p-c-Jun and p-JNK is associated with neuronal cell death in diabetic rat retinas and retinas exposed to high glucose. Neuroprotective effect of TUDCA and NT-4 is correlated with the suppression of p-c-Jun and p-JNK expression. These results provide a better understanding of the neurodegenerative process underlying DR.

Topics: Animals; Apoptosis; Cell Death; Diabetes Mellitus, Experimental; Diabetic Retinopathy; Glucose; In Vitro Techniques; JNK Mitogen-Activated Protein Kinases; Male; Nerve Growth Factors; Nerve Regeneration; Neurites; Neurons; Neuroprotective Agents; Phosphorylation; Proto-Oncogene Proteins c-jun; Rats; Rats, Sprague-Dawley; Retina; Retinal Ganglion Cells; Streptozocin; Taurochenodeoxycholic Acid

Obesity has become a serious public health problem in the developed world. Increased mass of adipose tissue in the obese is due to an increase in both the size (hypertrophy) and number (hyperplasia) of adipocytes. The chemical chaperone tauroursodeoxycholic acid (TUDCA) not only decreases endoplasmic reticulum (ER) stress, but also plays a role as a leptin-sensitizing agent for preadipocytes in mice and humans. In this study, we examine whether TUDCA has an effect on adipogenesis from human adipose-derived stem cells (hASCs). Therefore, the effect of TUDCA on ER stress, lipid accumulation, and adipogenic differentiation from hASCs was investigated using histological staining, reverse-transcriptase polymerase chain reaction (RT-PCR), and western blotting in vitro. It was found that TUDCA treatment of hASCs significantly decreases the representative ER stress marker (glucose-regulated protein 78 kDa (GRP78)), adipogenic markers (peroxisome proliferator-activated receptor gamma (PPARγ) and glycerol-3-phosphate dehydrogenase 1 (GPDH)), and lipid accumulation. Furthermore, we confirmed that TUDCA treatment of hASCs significantly decreased in vivo adipogenic tissue formation and ER stress comparing with PBS treatment of hASCs. The results indicate that TUDCA plays a critical role in adipogenesis from hASCs by modulating ER stress and, therefore, has potential pharmacologic and therapeutic applications as an anti-obesity agent.

Topics: Adipogenesis; Adipose Tissue; Animals; Cell Lineage; Cell Proliferation; Cell Survival; Endoplasmic Reticulum Chaperone BiP; Endoplasmic Reticulum Stress; Gene Expression Regulation; Humans; Lipid Metabolism; Mesoderm; Mice; Mice, Nude; Stem Cells; Taurochenodeoxycholic Acid

Ablation of the mitochondrial fusion and endoplasmic reticulum (ER)-tethering protein Mfn2 causes ER stress, but whether this is just an epiphenomenon of mitochondrial dysfunction or a contributor to the phenotypes in mitofusin (Mfn)-depleted Drosophila melanogaster is unclear. In this paper, we show that reduction of ER dysfunction ameliorates the functional and developmental defects of flies lacking the single Mfn mitochondrial assembly regulatory factor (Marf). Ubiquitous or neuron- and muscle-specific Marf ablation was lethal, altering mitochondrial and ER morphology and triggering ER stress that was conversely absent in flies lacking the fusion protein optic atrophy 1. Expression of Mfn2 and ER stress reduction in flies lacking Marf corrected ER shape, attenuating the developmental and motor defects. Thus, ER stress is a targetable pathogenetic component of the phenotypes caused by Drosophila Mfn ablation.

Topics: Animals; Drosophila melanogaster; Drosophila Proteins; Endoplasmic Reticulum Stress; Genetic Complementation Test; Humans; Locomotion; Membrane Proteins; Mice; Mitochondria; Phenylbutyrates; RNA Interference; Taurochenodeoxycholic Acid

Endoplasmic reticulum (ER) stress might play an important role in a range of neurological diseases; however, this phenomenon's role in subarachnoid hemorrhage (SAH) remains unclear. In this study, we explored the potential role of endoplasmic reticulum stress in early brain injury following SAH.84 rats were used for an endovascular perforation-induced subarachnoid hemorrhage model. The rats were intraperitoneally pretreated with the ER stress inducer tunicamycin (Tm) or with the inhibitor tauroursodeoxycholic acid (TUDCA) before SAH onset. An intracerebral ventricular infusion of autophagy inhibitor 3-methyladenine (3-MA) was also used to determine the relation between autophagy and ER stress in early brain injury following SAH. At 24h, rats were neurologically evaluated, and their brains were extracted for molecular biological and histological studies. ER stress was activated in rats after 24h of SAH. Enhanced ER stress via Tm pretreatment significantly improved neurological deficits, attenuated the expression of pro-apoptotic molecules of caspase-3 and reduced the number of TUNEL-positive cells. In contrast, the ER stress inhibitor TUDCA aggravated neurological deficits and apoptotic cell death. Western blot analysis revealed that levels of the autophagic protein Beclin 1 and the ratio of LC3-II to LC3-I were both increased by Tm infusion and reduced by TUDCA administration. The suppression of autophagic activity with 3-MA attenuated Tm-induced anti-apoptotic effects. Our study indicates that ER stress alleviates early brain injury following SAH via inhibiting apoptosis. This neuroprotective effect is most likely exerted by autophagy activation.

Topics: Animals; Apoptosis; Autophagy; Endoplasmic Reticulum Stress; Male; Rats, Sprague-Dawley; Subarachnoid Hemorrhage; Taurochenodeoxycholic Acid; Tunicamycin

Bile acids are steroid acids found predominantly in the bile of mammals. The bile acid conjugate tauroursodeoxycholic acid (TUDCA) is a neuroprotective agent in different animal models of stroke and neurological diseases. However, the anti-inflammatory properties of TUDCA in the central nervous system (CNS) remain unknown.. The acute neuroinflammation model of intracerebroventricular (icv) injection with bacterial lipopolysaccharide (LPS) in C57BL/6 adult mice was used herein. Immunoreactivity against Iba-1, GFAP, and VCAM-1 was measured in coronal sections in the mice hippocampus. Primary cultures of microglial cells and astrocytes were obtained from neonatal Wistar rats. Glial cells were treated with proinflammatory stimuli to determine the effect of TUDCA on nitrite production and activation of inducible enzyme nitric oxide synthase (iNOS) and NFκB luciferase reporters. We studied the effect of TUDCA on transcriptional induction of iNOS and monocyte chemotactic protein-1 (MCP-1) mRNA as well as induction of protein expression and phosphorylation of different proteins from the NFκB pathway.. TUDCA specifically reduces microglial reactivity in the hippocampus of mice treated by icv injection of LPS. TUDCA treatment reduced the production of nitrites by microglial cells and astrocytes induced by proinflammatory stimuli that led to transcriptional and translational diminution of the iNOS. This effect might be due to inhibition of the NFκB pathway, activated by proinflammatory stimuli. TUDCA decreased in vitro microglial migration induced by both IFN-γ and astrocytes treated with LPS plus IFN-γ. TUDCA inhibition of MCP-1 expression induced by proinflammatory stimuli could be in part responsible for this effect. VCAM-1 inmunoreactivity in the hippocampus of animals treated by icv LPS was reduced by TUDCA treatment, compared to animals treated with LPS alone.. We show a triple anti-inflammatory effect of TUDCA on glial cells: i) reduced glial cell activation, ii) reduced microglial cell migratory capacity, and iii) reduced expression of chemoattractants (e.g., MCP-1) and vascular adhesion proteins (e.g., VCAM-1) required for microglial migration and blood monocyte invasion to the CNS inflammation site. Our results present a novel TUDCA anti-inflammatory mechanism, with therapeutic implications for inflammatory CNS diseases.

Topics: Animals; Animals, Newborn; Calcium-Binding Proteins; Cell Movement; Cell Proliferation; Cells, Cultured; Cholagogues and Choleretics; Disease Models, Animal; Encephalitis; Gene Expression Regulation; Glial Fibrillary Acidic Protein; Hippocampus; Injections, Intraventricular; Lipopolysaccharides; Mice, Inbred C57BL; Microfilament Proteins; Neuroglia; Nitrites; Rats, Wistar; Taurochenodeoxycholic Acid; Vascular Cell Adhesion Molecule-1

Mutations in retinoid isomerase, RPE65, or lecithin-retinol acyltransferase (LRAT) disrupt 11-cis-retinal recycling and cause Leber congenital amaurosis (LCA), the most severe retinal dystrophy in early childhood. We used Lrat (-/-), a murine model for LCA, to investigate the mechanism of rapid cone degeneration. We found that mislocalized M-opsin was degraded whereas mislocalized S-opsin accumulated in Lrat (-/-) cones before the onset of massive ventral/central cone degeneration. Since the ventral and central retina expresses higher levels of S-opsin than the dorsal retina in mice, our results may explain why ventral and central cones degenerate more rapidly than dorsal cones in Rpe65 (-/-) and Lrat (-/-) LCA models. In addition, human blue opsin and mouse S-opsin, but not mouse M-opsin or human red/green opsins, aggregated to form cytoplasmic inclusions in transfected cells, which may explain why blue cone function is lost earlier than red/green-cone function in LCA patients. The aggregation of short-wavelength opsins likely caused rapid cone degenerations through an ER stress pathway as demonstrated in both the Lrat (-/-) retina and transfected cells. Based on this mechanism, we designed a new therapy of LCA by reducing ER stress. We found that systemic injection of an ER chemical chaperone, tauroursodeoxycholic acid (TUDCA), is effective in reducing ER stress, preventing apoptosis, and preserving cones in Lrat (-/-) mice.

Topics: Acyltransferases; Animals; Cholagogues and Choleretics; cis-trans-Isomerases; Disease Models, Animal; Endoplasmic Reticulum Stress; Humans; Leber Congenital Amaurosis; Light; Mice; Mice, Inbred C57BL; Mice, Knockout; Opsins; Retinal Cone Photoreceptor Cells; Rod Opsins; Taurochenodeoxycholic Acid

Endoplasmic reticulum (ER) stress has been implicated in the development of nonalcoholic steatohepatitis. A methionine-choline-deficient (MCD) diet induces robust ER stress response and steatohepatitis, but the effects of ER stress modulation on the course of steatohepatitis remain uncertain. The present study evaluated whether reducing ER stress using the chemical chaperone tauroursodeoxycholic acid (TUDCA) could limit hepatocyte lipoapoptosis and progression of MCD diet-induced steatohepatitis.. HuH7 cells stably transfected with sodium taurocholate cotransporting polypeptide (HuH-Ntcp cells) and palmitate (PA) were used. Experimental steatohepatitis was induced in male C57BL/6 mice using an MCD diet, and three different doses of TUDCA (500, or 1,000 mg/kg, once daily; or 500 mg/kg twice daily) were administered by gavage from the start of the MCD diet regimen or after 4 weeks.. TUDCA reduced PA-induced ER stress as manifested by decreased eIF2α phosphorylation, XBP1 splicing and expression of BiP, ATF4, and CHOP in HuH-Ntcp cells. TUDCA also decreased PA-induced JNK phosphorylation, Puma up-regulation and Bax activation, which in turn suppressed caspase-dependent hepatocyte lipoapoptosis. Mice given TUDCA did not show a significant decrease in the intrahepatic triglyceride contents and steatosis. However, TUDCA treatment significantly reduced hepatic damage compared to controls for both early and late treatment groups. TUDCA treatment reduced the expression of ER stress markers and pro-apoptotic proteins, leading to decreased apoptosis and oxidative stress. Finally, TUDCA reduced histological fibrosis along with the down-regulation of pro-fibrotic gene expression in both early and late treatment groups.. These results show that TUDCA attenuates the progression of MCD diet-induced steatohepatitis by reducing ER stress.

Topics: Animal Feed; Animals; Apoptosis; Biomarkers; Choline Deficiency; Disease Progression; Drug Administration Schedule; Endoplasmic Reticulum Stress; Fatty Liver; Gastrointestinal Agents; Immunoblotting; Male; Methionine; Mice; Mice, Inbred C57BL; Non-alcoholic Fatty Liver Disease; Real-Time Polymerase Chain Reaction; Reverse Transcriptase Polymerase Chain Reaction; Taurochenodeoxycholic Acid

Radiotherapy, which is one of the most effective approaches to the treatment of various cancers, plays an important role in malignant cell eradication in the pelvic area and abdomen. However, it also generates some degree of intestinal injury. Apoptosis in the intestinal epithelium is the primary pathological factor that initiates radiation-induced intestinal injury, but the mechanism by which ionizing radiation (IR) induces apoptosis in the intestinal epithelium is not clearly understood. Recently, IR has been shown to induce endoplasmic reticulum (ER) stress, thereby activating the unfolded protein response (UPR) signaling pathway in intestinal epithelial cells. However, the consequences of the IR-induced activation of the UPR signaling pathway on radiosensitivity in intestinal epithelial cells remain to be determined. In this study, we investigated the role of ER stress responses in IR-induced intestinal epithelial cell death. We show that chemical ER stress inducers, such as tunicamycin or thapsigargin, enhanced IR-induced caspase 3 activation and DNA fragmentation in intestinal epithelial cells. Knockdown of Xbp1 or Atf6 with small interfering RNA inhibited IR-induced caspase 3 activation. Treatment with chemical chaperones prevented ER stress and subsequent apoptosis in IR-exposed intestinal epithelial cells. Our results suggest a pro-apoptotic role of ER stress in IR-exposed intestinal epithelial cells. Furthermore, inhibiting ER stress may be an effective strategy to prevent IR-induced intestinal injury.

Topics: Animals; Apoptosis; Caspase 3; Cell Death; Cell Line; Endoplasmic Reticulum Stress; Enzyme Activation; Epithelial Cells; Intestinal Mucosa; Phenylbutyrates; Rats; Taurochenodeoxycholic Acid; Thapsigargin; Tunicamycin; Unfolded Protein Response

Increasing evidence indicates that endoplasmic reticulum (ER) stress is involved in various diseases. In nongestational tissues, several markers of the unfolded protein response (UPR) have been shown to regulate the inflammatory response. Thus, the aim of this study was to determine the effect of human labor on markers of ER stress in fetal membranes and myometrium. In addition, the effect of ER stress inhibition on the expression and secretion of proinflammatory and prolabor mediators was also assessed. The markers of ER stress, GRP78, IRE1, and spliced XBP1 (XBP1s), were significantly increased in fetal membranes and myometrium after term and preterm labor compared to nonlaboring samples. Given that inflammation is considered to be one of the leading causes of spontaneous preterm birth, here we used bacterial endotoxin lipopolysaccharide (LPS) as a model for infection-induced preterm birth. In term nonlabored fetal membranes and myometrium, LPS induced UPR activation as evidenced by a significant increase in the expression of GRP78, IRE1, and XBP1s in fetal membranes and myometrium. The use of the chemical chaperones 4-phenylbutyric acid (4-PBA) and tauroursodeoxycholic acid (TUDCA) alleviated ER stress induced by LPS. 4-PBA and TUDCA also ameliorated the increase in LPS-induced prolabor mediators. Our data suggest that the UPR may regulate the inflammatory responses associated with labor or infection in fetal membranes and myometrium of pregnant term and preterm women. Thus, the use of ER stress inhibitors, in particular 4-PBA or TUDCA, may be a potential therapeutic strategy for the prevention of infection-mediated spontaneous preterm birth.

Topics: Adult; Alternative Splicing; Biomarkers; Cesarean Section; DNA-Binding Proteins; Endoplasmic Reticulum Chaperone BiP; Endoplasmic Reticulum Stress; Endoribonucleases; Extraembryonic Membranes; Female; Gene Expression Regulation, Developmental; Heat-Shock Proteins; Humans; Labor, Obstetric; Myometrium; Obstetric Labor, Premature; Phenylbutyrates; Pregnancy; Protein Serine-Threonine Kinases; Regulatory Factor X Transcription Factors; Taurochenodeoxycholic Acid; Tissue Culture Techniques; Tocolytic Agents; Transcription Factors; Unfolded Protein Response; Up-Regulation; X-Box Binding Protein 1

The unfolded protein response (UPR) is activated in neurodegenerative tauopathies such as Alzheimer's disease (AD) in close connection with early stages of tau pathology. Metabolic disturbances are strongly associated with increased risk for AD and are a potent inducer of the UPR. Here, we demonstrate that metabolic stress induces the phosphorylation of endogenous tau via activation of the UPR. Strikingly, upon restoration of the metabolic homeostasis, not only the levels of the UPR markers pPERK, pIRE1α and BiP, but also tau phosphorylation are reversed both in cell models as well as in torpor, a physiological hypometabolic model in vivo. Intervention in the UPR using the global UPR inhibitor TUDCA or a specific small-molecule inhibitor of the PERK signaling pathway, inhibits the metabolic stress-induced phosphorylation of tau. These data support a role for UPR-mediated tau phosphorylation as part of an adaptive response to metabolic stress. Failure to restore the metabolic homeostasis will lead to prolonged UPR activation and tau phosphorylation, and may thus contribute to AD pathogenesis. We demonstrate that the UPR is functionally involved in the early stages of tau pathology. Our data indicate that targeting of the UPR may be employed for early intervention in tau-related neurodegenerative diseases.

Topics: Alzheimer Disease; Animals; Cell Line, Tumor; Cerebral Cortex; Cold Temperature; Corpus Striatum; Cricetinae; Deoxyglucose; eIF-2 Kinase; Endoribonucleases; Hippocampus; Humans; Phosphorylation; Protein Serine-Threonine Kinases; Signal Transduction; Stress, Physiological; tau Proteins; Taurochenodeoxycholic Acid; Tunicamycin; Unfolded Protein Response

Rab proteins (Ras homologous for brain) play an important role in vesicle trafficking. Rab4 and Rab11 are involved in vesicular trafficking to the plasma membrane from early endosomes and recycling endosomes, respectively. Tauroursodeoxycholate (TUDC) and cAMP increase bile formation, in part, by increasing plasma membrane localization of multidrug resistance-associated protein 2 (MRP2). The goal of the present study was to determine the role of these Rab proteins in the trafficking of MRP2 by testing the hypothesis that Rab11 and/or Rab4 facilitate cAMP- and TUDC-induced MRP2 translocation to the plasma membrane. Studies were conducted in HuH-NTCP cells (HuH7 cells stably transfected with human NTCP), which constitutively express MRP2. HuH-NTCP cells were transfected with Rab11-WT and GDP-locked dominant inactive Rab11-GDP or with Rab4-GDP to study the role of Rab11 and Rab4. A biotinylation method and a GTP overlay assay were used to determine plasma membrane MRP2 and activation of Rab proteins (Rab11 and Rab4), respectively. Cyclic AMP and TUDC increased plasma membrane MRP2 and stimulated Rab11 activity. Plasma membrane translocation of MRP2 by cAMP and TUDC was increased and inhibited in cells transfected with Rab11-WT and Rab11-GDP, respectively. Cyclic AMP (previous study) and TUDC increased Rab4 activity. However, cAMP- and TUDC-induced increases in MRP2 were not inhibited by Rab4-GDP. Taken together, these results suggest that Rab11 is involved in cAMP- and TUDC-induced MRP2 translocation to the plasma membrane.

Topics: ATP Binding Cassette Transporter, Subfamily B; ATP-Binding Cassette Sub-Family B Member 4; Cell Line; Cell Membrane; Cyclic AMP; Hepatocytes; Humans; Organic Anion Transporters, Sodium-Dependent; Protein Transport; rab GTP-Binding Proteins; rab4 GTP-Binding Proteins; Symporters; Taurochenodeoxycholic Acid

To discriminate and determine of the artificial bear bile of the compound bile capsule.. Taking the pharmacopoeia as reference, the artificial bear bile was discriminated and determined by HPLC.. The compound bile capsule and the control sample had chromatographic peak at the same time from HPLC. The content of the artificial bear bile was above 10 mg per tablets.. The artificial bear bile of compound bile capsules can be discriminated effectively and determined accurately by HPLC method.

Topics: Animals; Bile; Capsules; Chromatography, High Pressure Liquid; Discriminant Analysis; Medicine, Chinese Traditional; Taurochenodeoxycholic Acid; Ursidae

Ulcerative colitis (UC) is characterized by increased epithelial cell death and subsequent breakdown of the intestinal epithelial barrier, which perpetuates chronic intestinal inflammation. Since fecal bile acid dysmetabolism is associated with UC and tauroursodeoxycholic acid (TUDCA) has been shown to improve murine colitis, we evaluated the effect of TUDCA on intestinal epithelial cell death in a mouse model of UC-like barrier dysfunction elicited by dextran sulfate sodium (DSS). We identified the prevention of colonic caspase-3 induction, a key proapoptotic marker which was also over-activated in UC, as the earliest event resulting in a clear clinical benefit. Whereas vehicle-treated mice showed a cumulative mortality of 40%, all TUDCA-treated mice survived the DSS experiment during a 14-day follow-up period. In line with a barrier protective effect, TUDCA decreased bacterial translocation to the spleen and stimulated mucin production. Similarly, TUDCA inhibited lipopolysaccharide-induced intestinal permeability and associated enterocyte apoptosis. The anti-apoptotic effect was confirmed in vitro by a dose-dependent inhibition of both receptor-dependent (using tumor necrosis factor and Fas ligand) and receptor-independent (staurosporine) caspase-3 induction in HT29 colonic epithelial cells. These data imply that caspase-3 activation is an early marker of colitis that is prevented by TUDCA treatment. These data, together with the previously reported beneficial effect in colitis, suggest that TUDCA could be an add-on strategy to current immunosuppressive treatment of UC patients.

Topics: Adolescent; Adult; Aged; Animals; Apoptosis; Caspase 3; Child; Colitis; Dextran Sulfate; Epithelial Cells; Female; HT29 Cells; Humans; Intestinal Mucosa; Male; Mice; Mice, Inbred C57BL; Middle Aged; Phosphatidylinositol 3-Kinases; Receptors, Vitronectin; Taurochenodeoxycholic Acid

Retinitis pigmentosa is a heterogeneous group of inherited neurodegenerative retinal disorders characterized by a progressive peripheral vision loss and night vision difficulties, subsequently leading to central vision impairment. Chronic microglia activation is associated with various neurodegenerative diseases including retinitis pigmentosa. The objective of this study was to quantify microglia activation in the retina of P23H rats, an animal model of retinitis pigmentosa, and to evaluate the therapeutic effects of TUDCA (tauroursodeoxycholic acid), which has been described as a neuroprotective compound.. For this study, homozygous P23H line 3 and Sprague-Dawley (SD) rats were injected weekly with TUDCA (500 mg/kg, ip) or vehicle (saline) from 20 days to 4 months old. Vertical retinal sections and whole-mount retinas were immunostained for specific markers of microglial cells (anti-CD11b, anti-Iba1 and anti-MHC-II). Microglial cell morphology was analyzed and the number of retinal microglial was quantified.. Microglial cells in the SD rat retinas were arranged in regular mosaics homogenously distributed within the plexiform and ganglion cell layers. In the P23H rat retina, microglial cells increased in number in all layers compared with control SD rat retinas, preserving the regular mosaic distribution. In addition, a large number of amoeboid CD11b-positive cells were observed in the P23H rat retina, even in the subretinal space. Retinas of TUDCA-treated P23H animals exhibited lower microglial cell number in all layers and absence of microglial cells in the subretinal space.. These results report novel TUDCA anti-inflammatory actions, with potential therapeutic implications for neurodegenerative diseases, including retinitis pigmentosa.

Topics: Animals; Cell Count; Disease Models, Animal; Immunohistochemistry; Microglia; Microscopy, Confocal; Neuroprotective Agents; Rats; Rats, Sprague-Dawley; Retinal Degeneration; Taurochenodeoxycholic Acid

Endoplasmic reticulum (ER) stress and inappropriate adaptation through the unfolded protein response (UPR) are predominant features of pathological processes. However, little is known about the link between ER stress and endovascular injury. We investigated the involvement of ER stress in neointima hyperplasia after vascular injury. The femoral arteries of 7-8-week-old male mice were subjected to wire-induced vascular injury. After 4 weeks, immunohistological analysis showed that ER stress markers were upregulated in the hyperplastic neointima. Neointima formation was increased by 54.8% in X-box binding protein-1 (XBP1) heterozygous mice, a model of compromised UPR. Knockdown of Xbp1 in human coronary artery smooth muscle cells (CASMC) in vitro promoted cell proliferation and migration. Furthermore, treatment with ER stress reducers, 4-phenylbutyrate (4-PBA) and tauroursodeoxycholic acid (TUDCA), decreased the intima-to-media ratio after wire injury by 50.0% and 72.8%, respectively. Chronic stimulation of CASMC with PDGF-BB activated the UPR, and treatment with 4-PBA and TUDCA significantly suppressed the PDGF-BB-induced ER stress markers in CASMC and the proliferation and migration of CASMC. In conclusion, increased ER stress contributes to neointima formation after vascular injury, while UPR signaling downstream of XBP1 plays a suppressive role. Suppression of ER stress would be a novel strategy against post-angioplasty vascular restenosis.

Topics: Animals; Becaplermin; Cell Movement; Cell Proliferation; Cells, Cultured; Coronary Vessels; DNA-Binding Proteins; Endoplasmic Reticulum Stress; Endothelial Cells; Femoral Artery; Gene Expression Regulation; Heterozygote; Humans; Hyperplasia; Male; Mice; Myocytes, Smooth Muscle; Neointima; Phenylbutyrates; Proto-Oncogene Proteins c-sis; Regulatory Factor X Transcription Factors; Signal Transduction; Taurochenodeoxycholic Acid; Transcription Factors; Unfolded Protein Response; Vascular System Injuries; X-Box Binding Protein 1

Inevitable warm ischemia time before organ procurement aggravates posttransplantation ischemia-reperfusion injury. Endoplasmic reticulum (ER) stress is involved in ischemia-reperfusion injury, but its role in donation after cardiac death (DCD) liver transplantation is not clear and the effect of ER stress inhibitors, tauroursodeoxycholic acid (TUDCA) and 4-phenyl butyric acid (PBA), on the prognosis of recipient of DCD liver transplantation remains unclear.. Male Sprague-Dawley rats (8-10 weeks) were randomly divided into the control group: liver grafts without warm ischemia were implanted; DCD group: warm ischemia time of the liver grafts was 60 minutes; TUDCA and PBA groups: based on the DCD group, donors were intraperitoneally injected with TUDCA or PBA 30 minutes before the organ procurements. Serum aminotransferase levels, oxidative stress activation and expression of ER stress signal molecules were evaluated. Pathological examinations were performed. The survivals of the recipients in each group were compared for 14 days.. Compared with the control group, DCD rats had significantly higher levels of serum aminotransferase at 6 hours, 1 day and 3 days after operation (P<0.01, 0.01 and 0.05, respectively) and oxidative indices (P<0.01 for both malondialdehyde and 8-hydroxy deoxyguanosine), more severe liver damage (P<0.01) and up-regulated ER stress signal expressions (P<0.01 for GRP78, phos-eIF2alpha1, CHOP, ATF-4, ATF-6, PERK, XBP-1 and pro-caspase-12). All recipients died within 3 days after liver transplantation. Administration of TUDCA or PBA significantly decreased aminotransferase levels (P<0.05), increased superoxide dismutase activities (P<0.01), alleviated liver damage (P<0.01), down-regulated ER stress signal expressions (P<0.01) and improved postoperative survivals (P<0.01).. ER stress was involved with DCD liver transplantation in rats. Preoperative intraperitoneally injection of TUDCA or PBA protected ER stress and improved prognosis.

Topics: Alanine Transaminase; Animals; Aspartate Aminotransferases; Cholagogues and Choleretics; Death; Delayed Graft Function; Endoplasmic Reticulum Stress; Liver Transplantation; Male; Models, Animal; Oxidative Stress; Phenylbutyrates; Prognosis; Rats, Sprague-Dawley; Reperfusion Injury; Survival Rate; Taurochenodeoxycholic Acid

The low survival and differentiation rates of stem cells after either transplantation or neural injury have been a major concern of stem cell-based therapy. Thus, further understanding long-term survival and differentiation of stem cells may uncover new targets for discovery and development of novel therapeutic approaches. We have previously described the impact of mitochondrial apoptosis-related events in modulating neural stem cell (NSC) fate. In addition, the endogenous bile acid, tauroursodeoxycholic acid (TUDCA) was shown to be neuroprotective in several animal models of neurodegenerative disorders by acting as an anti-apoptotic and anti-oxidant molecule at the mitochondrial level. Here, we hypothesize that TUDCA might also play a role on NSC fate decision. We found that TUDCA prevents mitochondrial apoptotic events typical of early-stage mouse NSC differentiation, preserves mitochondrial integrity and function, while enhancing self-renewal potential and accelerating cell cycle exit of NSCs. Interestingly, TUDCA prevention of mitochondrial alterations interfered with NSC differentiation potential by favoring neuronal rather than astroglial conversion. Finally, inhibition of mitochondrial reactive oxygen species (mtROS) scavenger and adenosine triphosphate (ATP) synthase revealed that the effect of TUDCA is dependent on mtROS and ATP regulation levels. Collectively, these data underline the importance of mitochondrial stress control of NSC fate decision and support a new role for TUDCA in this process.

Topics: Animals; Apoptosis; Astrocytes; Cell Communication; Cell Cycle; Cell Differentiation; Cell Proliferation; Mice; Mitochondria; Neural Stem Cells; Neurons; Reactive Oxygen Species; Signal Transduction; Taurochenodeoxycholic Acid

Paraquat is a commonly used herbicide; however, it is highly toxic to humans and animals. Exposure to paraquat causes severe lung damage, leading to pulmonary fibrosis. However, it has not been well clarified as how paraquat causes cellular damage, and there is no established standard therapy for paraquat poisoning. Meanwhile, endoplasmic reticulum stress (ERS) is reported to be one of the causative factors in many diseases, although mammalian cells have a defense mechanism against ERS-induced apoptosis (unfolded protein response). Here, we demonstrated that paraquat changed the expression levels of unfolded protein response-related molecules, resulting in ERS-related cell death in human lung epithelial A549 cells. Moreover, treatment with sodium tauroursodeoxycholate (TUDCA), a chemical chaperone, crucially rescued cells from death caused by exposure to paraquat. These results indicate that paraquat toxicity may be associated with ERS-related molecules/events. Through chemical chaperone activity, treatment with TUDCA reduced paraquat-induced ERS and mildly suppressed cell death. Our findings also suggest that TUDCA treatment represses the onset of pulmonary fibrosis caused by paraquat, and therefore chemical chaperones may have novel therapeutic potential for the treatment of paraquat poisoning.

Topics: Apoptosis; Caspase 3; Cell Line; DNA-Binding Proteins; Endoplasmic Reticulum Stress; Enzyme Activation; Eukaryotic Initiation Factor-2; Herbicides; Humans; Lung; Mitochondrial Proton-Translocating ATPases; Paraquat; Regulatory Factor X Transcription Factors; Respiratory Mucosa; Taurochenodeoxycholic Acid; Transcription Factors; Unfolded Protein Response

Topics: Animals; Hepatocytes; Humans; Integrin alpha5beta1; Male; Taurochenodeoxycholic Acid

Prenatal ethanol exposure results in increased glucose production in adult rat offspring and this may involve modulation of protein acetylation by cellular stress. We used adult male offspring of dams given ethanol during gestation days 1-7 (early), 8-14 (mid) and 15-21 (late) compared with those from control dams. A group of ethanol offspring was treated with tauroursodeoxycholic acid (TUDCA) for 3 weeks. We determined gluconeogenesis, phosphoenolpyruvate carboxykinase (PEPCK), glucose-6-phosphatase, hepatic free radicals, histone deacetylases (HDAC), acetylated foxo1, acetylated PEPCK, and C/EBP homologous protein as a marker of endoplasmic reticulum stress. Prenatal ethanol during either of the 3 weeks of pregnancy increased gluconeogenesis, gluconeogenic genes, oxidative and endoplasmic reticulum stresses, sirtuin-2 and HDAC3, 4, 5, and 7 in adult offspring. Conversely, prenatal ethanol reduced acetylation of foxo1 and PEPCK. Treatment of adult ethanol offspring with TUDCA reversed all these abnormalities. Thus, prenatal exposure of rats to ethanol results in long lasting oxidative and endoplasmic reticulum stresses explaining increased expression of gluconeogenic genes and HDAC proteins which, by deacetylating foxo1 and PEPCK, contribute to increased gluconeogenesis. These anomalies occurred regardless of the time of ethanol exposure during pregnancy, including early embryogenesis. As these anomalies were reversed by treatment of the adult offspring with TUDCA, this compound has therapeutic potentials in the treatment of glucose intolerance associated with prenatal ethanol exposure.

Topics: Acetylation; Aging; Animals; Area Under Curve; Blood Glucose; Body Weight; Cell Nucleus; Endoplasmic Reticulum Stress; Ethanol; Female; Forkhead Transcription Factors; Free Radicals; Gluconeogenesis; Glucose Intolerance; Glucose Tolerance Test; Histone Deacetylases; Insulin; Liver; Male; Nerve Tissue Proteins; Pregnancy; Prenatal Exposure Delayed Effects; Rats; Rats, Sprague-Dawley; Stress, Physiological; Taurochenodeoxycholic Acid

Both endoplasmic reticulum (ER) stress and autophagy have been shown to display dual roles in cell survival in multiple cell lines. There is a reported but poorly understood link between ER stress, autophagy, and cell death. We hypothesized that autophagy plays a role in ER stress-dependent cell death in rat hepatocytes.. Primary hepatocytes isolated from both lean and obese male Zucker rats were cultured and treated with tunicamycin (TM), tauroursodeoxycholic acid, 3-methyladenine, and wortmannin for 12 h. The ER stress-associated genes glucose-regulated protein 78 and C/EBP homologous protein were examined via quantitative real time polymerase chain reaction. Immunostaining with microtubule-associated protein 1 light chain 3 as well as electron microscopy were used to evaluate autophagy activity. Trypan blue exclusion was used to determine hepatocyte cell viability.. In both lean and steatotic hepatocytes, we found that TM induced both C/EBP homologous protein and glucose-regulated protein 78 messenger RNA expression. Cells with increased ER stress were undergoing increased autophagy and had a significant decrease in cell viability. Both tauroursodeoxycholic acid and 3-methyladenine treatments attenuated TM induced ER stress, autophagy, and cell death, whereas wortmannin treatment reduced autophagy and cell death but without changing ER stress.. These data suggest that autophagy is a likely downstream mediator of ER stress-induced cell death in rat hepatocytes. Further exploration of the link between autophagy and ER stress in hepatocyte injury will yield important information that may be leveraged for treatment of liver injuries such as ischemia/reperfusion.

Topics: Adenine; Androstadienes; Animals; Apoptosis; Autophagy; Cell Survival; Cells, Cultured; Disease Models, Animal; Endoplasmic Reticulum Stress; Fatty Liver; Hepatocytes; Male; Rats; Rats, Zucker; Taurochenodeoxycholic Acid; Tunicamycin; Wortmannin

Cardiac hypertrophy and myocardial infarction (MI) are two major causes of heart failure with different etiologies. However, the molecular mechanisms associated with these two diseases are not yet fully understood. So, this study was designed to decipher the process of cardiomyocyte apoptosis during cardiac hypertrophy and MI in vivo. Our study revealed that mitochondrial outer membrane channel protein voltage-dependent anion channel-1 (VDAC1) was upregulated exclusively during cardiac hypertrophy, whereas 78 kDa glucose-regulated protein (GRP78) was exclusively upregulated during MI, which is an important upstream regulator of the endoplasmic reticulum (ER) stress pathway. Further downstream analysis revealed that mitochondrial pathway of apoptosis is instrumental in case of hypertrophy, whereas ER stress-induced apoptosis is predominant during MI, which was confirmed by treatment with either siRNA against VDAC1 or ER stress inhibitor tauroursodeoxycholic acid (TUDCA). Very interestingly, our data also showed that the expression and interaction of small heat-shock protein α-crystallin B (CRYAB) with VDAC1 was much more pronounced during MI compared with either hypertrophy or control. The study demonstrated for the first time that two different organelles--mitochondria and ER have predominant roles in mediating cardiomyocyte death signaling during hypertrophy and MI, respectively, and activation of CRYAB acts as a molecular switch in bypassing mitochondrial pathway of apoptosis during MI.

Topics: Animals; Apoptosis; Cardiomegaly; Endoplasmic Reticulum; Endoplasmic Reticulum Stress; Gene Expression Regulation; Heat-Shock Proteins; Male; Mitochondria; Myocardial Infarction; Myocytes, Cardiac; Rats; Rats, Wistar; RNA, Small Interfering; Signal Transduction; Taurochenodeoxycholic Acid; Voltage-Dependent Anion Channel 1

Bariatric surgery elevates serum bile acids. Conjugated bile acid administration, such as tauroursodeoxycholic acid (TUDCA), improves insulin sensitivity, whereas short-circuiting bile acid circulation through ileal interposition surgery in rats raises TUDCA levels. We hypothesized that bariatric surgery outcomes could be recapitulated by short circuiting the normal enterohepatic bile circulation. We established a model wherein male obese rats underwent either bile diversion (BD) or Sham (SH) surgery. The BD group had a catheter inserted into the common bile duct and its distal end anchored into the middistal jejunum for 4-5 weeks. Glucose tolerance, insulin and glucagon-like peptide-1 (GLP-1) response, hepatic steatosis, and endoplasmic reticulum (ER) stress were measured. Rats post-BD lost significantly more weight than the SH rats. BD rats gained less fat mass after surgery. BD rats had improved glucose tolerance, increased higher postprandial glucagon-like peptide-1 response and serum bile acids but less liver steatosis. Serum bile acid levels including TUDCA concentrations were higher in BD compared to SH pair-fed rats. Fecal bile acid levels were not different. Liver ER stress (C/EBP homologous protein mRNA and pJNK protein) was decreased in BD rats. Bile acid gavage (TUDCA/ursodeoxycholic acid [UDCA]) in diet-induced obese rats, elevated serum TUDCA and concomitantly reduced hepatic steatosis and ER stress (C/EBP homologous protein mRNA). These data demonstrate the ability of alterations in bile acids to recapitulate important metabolic improvements seen after bariatric surgery. Further, our work establishes a model for focused study of bile acids in the context of bariatric surgery that may lead to the identification of therapeutics for metabolic disease.

Topics: Animals; Bariatric Surgery; Bile Acids and Salts; Endoplasmic Reticulum Stress; Glucagon-Like Peptide 1; Male; Obesity; Rats; Taurochenodeoxycholic Acid

Despite the recent attention focused on the important role of autophagy in maintaining podocyte homeostasis, little is known about the changes and mechanisms of autophagy in podocyte dysfunction under diabetic condition. In this study, we investigated the role of autophagy in podocyte biology and its involvement in the pathogenesis of diabetic nephropathy. Podocytes had a high basal level of autophagy. And basal autophagy inhibition either by 3-methyladenenine (3-MA) or by Beclin-1 siRNA was detrimental to its architectural structure. However, under diabetic condition in vivo and under high glucose conditions in vitro, high basal level of autophagy in podocytes became defective and defective autophagy facilitated the podocyte injury. Since the dynamics of endoplasmic reticulum(ER) seemed to play a vital role in regulating the autophagic flux, the results that Salubrinal/Tauroursodeoxycholic acid (TUDCA) could restore defective autophagy further indicated that the evolution of autophagy may be mediated by the changes of cytoprotective output in the ER stress. Finally, we demonstrated in vivo that the autophagy of podocyte was inhibited under diabetic status and TUDCA could improve defective autophagy. Taken together, these data suggested that autophagy might be interrupted due to the failure of ER cytoprotective capacity upon high glucose induced unmitigated stress, and the defective autophagy might accelerate the irreparable progression of diabetic nephropathy.

Topics: Adenine; Animals; Apoptosis Regulatory Proteins; Autophagy; Beclin-1; Diabetic Nephropathies; Endoplasmic Reticulum; Hyperglycemia; Mice; Podocytes; RNA, Small Interfering; Taurochenodeoxycholic Acid

The endoplasmic reticulum (ER) chaperone tauroursodeoxycholic acid (TUDCA) has exhibited promises in the treatment of obesity, although its impact on obesity-induced cardiac dysfunction is unknown. This study examined the effect of TUDCA on cardiomyocyte function in high-fat diet-induced obesity.. Adult mice were fed low or high fat diet for 5 months prior to treatment of TUDCA (300 mg/kg. i.p., for 15d). Intraperitoneal glucose tolerance test (IPGTT), cardiomyocyte mechanical and intracellular Ca(2+) property, insulin signaling molecules including IRS-1, Akt, AMPK, ACC, GSK-3β, c-Jun, ERK and c-Jun N terminal kinase (JNK) as well as ER stress and intracellular Ca(2+) regulatory proteins were examined. Myocardial ultrastructure was evaluated using transmission electron microscopy (TEM).. High-fat diet depressed peak shortening (PS) and maximal velocity of shortening/relengthenin as well as prolonged relengthening duration. TUDCA reversed or overtly ameliorated high fat diet-induced cardiomyocyte dysfunction including prolongation in relengthening. TUDCA alleviated high-fat diet-induced decrease in SERCA2a and phosphorylation of phospholamban, increase in ER stress (GRP78/BiP, CHOP, phosphorylation of PERK, IRE1α and eIF2α), ultrastructural changes and mitochondrial permeation pore opening. High-fat diet feeding inhibited phosphorylation of AMPK and promoted phosphorylation of GSK-3β. TUDCA prevented high fat-induced dephosphorylation of AMPK but not GSK-3β. High fat diet promoted phosphorylation of IRS-1 (Ser(307)), JNK, and ERK without affecting c-Jun phosphorylation, the effect of which with the exception of ERK phosphorylation was attenuated by TUDCA.. These data depict that TUDCA may ameliorate high fat diet feeding-induced cardiomyocyte contractile and intracellular Ca(2+) defects through mechanisms associated with mitochondrial integrity, AMPK, JNK and IRS-1 serine phosphorylation.

Topics: Adenylate Kinase; Animals; Calcium; Diet, High-Fat; Endoplasmic Reticulum Chaperone BiP; Endoplasmic Reticulum Stress; Glucose Tolerance Test; Glycogen Synthase Kinase 3; Glycogen Synthase Kinase 3 beta; Insulin; Intracellular Space; Ion Channel Gating; Mice; Mice, Inbred C57BL; Mitochondria, Heart; Mitochondrial Membrane Transport Proteins; Mitochondrial Permeability Transition Pore; Myocardial Contraction; Myocardium; Myocytes, Cardiac; Proto-Oncogene Proteins c-akt; Signal Transduction; Taurochenodeoxycholic Acid

The cell-toxic bile salt glycochenodeoxycholic acid (GCDCA) and taurochenodeoxycholic acid (TCDCA) are responsible for hepatocyte demise in cholestatic liver diseases, while tauroursodeoxycholic acid (TUDCA) is regarded hepatoprotective. We demonstrate the direct mitochondrio-toxicity of bile salts which deplete the mitochondrial membrane potential and induce the mitochondrial permeability transition (MPT). The bile salt mediated mechanistic mode of destruction significantly differs from that of calcium, the prototype MPT inducer. Cell-toxic bile salts initially bind to the mitochondrial outer membrane. Subsequently, the structure of the inner boundary membrane disintegrates. And it is only thereafter that the MPT is induced. This progressive destruction occurs in a dose- and time-dependent way. We demonstrate that GCDCA and TCDCA, but not TUDCA, preferentially permeabilize liposomes containing the mitochondrial membrane protein ANT, a process resembling the MPT induction in whole mitochondria. This suggests that ANT is one decisive target for toxic bile salts. To our knowledge this is the first report unraveling the consecutive steps leading to mitochondrial destruction by cell-toxic bile salts.

Topics: Animals; Cell Membrane Permeability; Dose-Response Relationship, Drug; Glycochenodeoxycholic Acid; Liposomes; Liver; Membrane Potential, Mitochondrial; Mitochondria, Heart; Mitochondria, Liver; Mitochondrial ADP, ATP Translocases; Mitochondrial Membrane Transport Proteins; Mitochondrial Membranes; Mitochondrial Permeability Transition Pore; Myocardium; Rats; Taurochenodeoxycholic Acid; Voltage-Dependent Anion Channels

A contributing factor to increased peripheral resistance seen during hypertension is an increased production of endothelium-derived contractile factors (EDCFs). The main EDCFs are vasoconstrictor prostanoids, metabolites of arachidonic acid (AA) produced by Ca(2+)-dependent cytosolic phospholipase A2 (cPLA2) following phosphorylation (at Ser(505)) mediated by extracellular signal-regulated kinase (ERK1/2) and cyclooxygenase (COX) activations. Although endoplasmic reticulum (ER) stress has been shown to contribute to pathophysiological alterations in cardiovascular diseases, the relationship between ER stress and EDCF-mediated responses remains unclear. We tested the hypothesis that ER stress plays a role in EDCF-mediated responses via activation of the cPLA2/COX pathway in the aorta of the spontaneously hypertensive rat (SHR). Male SHR and Wistar-Kyoto rats (WKY) were treated with ER stress inhibitor, tauroursodeoxycholic acid or 4-phenlybutyric acid (TUDCA or PBA, respectively, 100 mg·kg(-1)·day(-1) ip) or PBS (control, 300 μl/day ip) for 1 wk. There was a decrease in systolic blood pressure in SHR treated with TUDCA or PBA compared with control SHR (176 ± 3 or 181 ± 5, respectively vs. 200 ± 2 mmHg). In the SHR, treatment with TUDCA or PBA normalized aortic (vs. control SHR) 1) contractions to acetylcholine (ACh), AA, and tert-butyl hydroperoxide, 2) ACh-stimulated releases of prostanoids (thromboxane A2, PGF2α, and prostacyclin), 3) expression of COX-1, 4) phosphorylation of cPLA2 and ERK1/2, and 5) production of H2O2. Our findings demonstrate a novel interplay between ER stress and EDCF-mediated responses in the aorta of the SHR. Moreover, ER stress inhibition normalizes such responses by suppressing the cPLA2/COX pathway.

Topics: Acetylcholine; Animals; Antihypertensive Agents; Aorta; Arachidonic Acid; bcl-2-Associated X Protein; Blood Pressure; Cells, Cultured; Cyclooxygenase 1; Dinoprost; Disease Models, Animal; Dose-Response Relationship, Drug; Endoplasmic Reticulum Stress; Endothelium, Vascular; Epoprostenol; Hydrogen Peroxide; Hypertension; Male; Membrane Proteins; Mitogen-Activated Protein Kinase 1; Mitogen-Activated Protein Kinase 3; Muscle, Smooth, Vascular; Myocytes, Smooth Muscle; Phenylbutyrates; Phospholipases A2, Cytosolic; Phosphorylation; Rats; Rats, Inbred SHR; Rats, Inbred WKY; Signal Transduction; Taurochenodeoxycholic Acid; tert-Butylhydroperoxide; Thromboxane A2; Vasoconstriction; Vasoconstrictor Agents; Vasodilator Agents

Preventing cyclophilin D (cypD) translocation to the inner mitochondrial membrane can limit lethal reperfusion injury through the inhibition of the opening of the mitochondrial permeability transition pore. Inhibition or loss of function of cypD may also result into an endoplasmic reticulum (ER) stress that has been shown to alter cell survival. We therefore questioned whether ER stress might play a role in the protection induced by CypD deficiency or inhibition. CypD-KO and NIM811 (a CypD inhibitor)-treated mice were subjected to a prolonged ischemia-reperfusion (I/R). Area at risk and infarct size was measured using blue dye and triphenyltetrazolium chloride staining. ER stress markers were measured in the hearts during the reperfusion phase. As expected, cypD-KO mice exhibited a decreased infarct size when compared to wild-type mice (8 ± 1 vs. 20 ± 4% of left ventricular weight; p < 0.01). CypD-deficient mice displayed an increased expression of ER stress proteins such as eukaryotic initiation factor 2α (eIF2α) or glucose regulated protein 78 (Grp78 or Bip). The ER stress inhibitor TUDCA prevented the infarct size reduction afforded by the loss of cypD function (mean infarct size averaged 21 ± 4% of LV weight, p < 0.01 vs. cypD-KO). Similar results were obtained when NIM811, an analog of cyclosporine A, was used to pharmacologically (instead of genetically) inhibit cypD function. This study suggests that the ER stress induced by the inhibition of cypD function plays a key role in protecting the heart against lethal ischemia-reperfusion injury.

Topics: Animals; Cyclophilins; Cyclosporine; Cyclosporins; Disease Models, Animal; Endoplasmic Reticulum Chaperone BiP; Endoplasmic Reticulum Stress; Heart; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Mitochondrial Membranes; Myocardial Infarction; Myocardial Reperfusion Injury; Peptidyl-Prolyl Isomerase F; Taurochenodeoxycholic Acid

The bile salt export pump (BSEP), encoded by the abcb11 gene, is the major canalicular transporter of bile acids from the hepatocyte. BSEP malfunction in humans causes bile acid retention and progressive liver injury, ultimately leading to end-stage liver failure. The natural, hydrophilic, bile acid ursodeoxycholic acid (UDCA) is efficacious in the treatment of cholestatic conditions, such as primary biliary cirrhosis and cholestasis of pregnancy. The beneficial effects of UDCA include promoting bile flow, reducing hepatic inflammation, preventing apoptosis, and maintaining mitochondrial integrity in hepatocytes. However, the role of BSEP in mediating UDCA efficacy is not known. Here, we used abcb11 knockout mice (abcb11-/-) to test the effects of acute and chronic UDCA administration on biliary secretion, bile acid composition, liver histology, and liver gene expression. Acutely infused UDCA, or its taurine conjugate (TUDC), was taken up by the liver but retained, with negligible biliary output, in abcb11-/- mice. Feeding UDCA to abcb11-/- mice led to weight loss, retention of bile acids, elevated liver enzymes, and histological damage to the liver. Semiquantitative RT-PCR showed that genes encoding Mdr1a and Mdr1b (canalicular) as well as Mrp4 (basolateral) transporters were upregulated in abcb11-/- mice. We concluded that infusion of UDCA and TUDC failed to induce bile flow in abcb11-/- mice. UDCA fed to abcb11-/- mice caused liver damage and the appearance of biliary tetra- and penta-hydroxy bile acids. Supplementation with UDCA in the absence of Bsep caused adverse effects in abcb11-/- mice.

Topics: Animals; ATP Binding Cassette Transporter, Subfamily B; ATP Binding Cassette Transporter, Subfamily B, Member 11; ATP-Binding Cassette Sub-Family B Member 4; ATP-Binding Cassette Transporters; Bile Canaliculi; Biological Transport; Cholestasis; Diet; Disease Models, Animal; Gene Expression Regulation; Infusions, Intravenous; Liver; Mice; Mice, Knockout; Multidrug Resistance-Associated Proteins; RNA, Messenger; Taurochenodeoxycholic Acid; Time Factors; Ursodeoxycholic Acid

Cadmium (Cd) is very toxic to plant cells and Cd(2+) stress induces programmed cell death (PCD) in Nicotiana tabacum L. cv. bright yellow-2 (BY-2) cells. In plants, PCD can be regulated through the endoplasmic reticulum (ER) stress-cell death signaling pathway. However, the mechanism of Cd(2+)-induced PCD remains unclear. In this study, we found that Cd(2+) treatment induced ER stress in tobacco BY-2 cells. The expression of two ER stress markers NtBLP4 and NtPDI and an unfolded protein response related transcription factor NtbZIP60 were upregulated with Cd(2+) stress. Meanwhile, the PCD triggered by prolonged Cd(2+) stress could be relieved by two ER chemical chaperones, 4-phenylbutyric acid and tauroursodeoxycholic acid. These results demonstrate that the ER stress-cell death signaling pathway participates in the mediation of Cd(2+)-induced PCD. Furthermore, the ER chaperone AtBiP2 protein alleviated Cd(2+)-induced ER stress and PCD in BY-2 cells based on the fact that heterologous expression of AtBiP2 in tobacco BY-2 cells reduced the expression of NtBLP4 and a PCD-related gene NtHsr203J under Cd(2+) stress conditions. In summary, these results suggest that the ER stress-cell death signaling pathway regulates Cd(2+)-induced PCD in tobacco BY-2 cells, and that the AtBiP2 protein act as a negative regulator in this process.

Topics: Apoptosis; Arabidopsis; Cadmium; Carrier Proteins; Endoplasmic Reticulum Stress; Nicotiana; Phenylbutyrates; Plant Cells; Plant Proteins; Plants, Genetically Modified; Signal Transduction; Taurochenodeoxycholic Acid

Aging is a dominant risk factor for end-stage renal disease. We analyzed the mechanism involved in age-related exacerbation of proteinuria-induced proximal tubular cell (PTC) damage by focusing on endoplasmic reticulum-related unfolded protein response (UPR). After equal-degree induction of proteinuria in 24-month-old (aged) and 3-month-old (young) mice by intraperitoneal free fatty acid-bound albumin overload, tubulointerstitial lesions were more severe in aged than in young mice. In aged PTCs, proteinuria-induced cell-adaptive UPR resulting from induction of the molecular chaperone BiP was significantly suppressed, whereas proapoptotic UPR with CHOP overexpression was enhanced. Treatment with the exogenous molecular chaperone tauroursodeoxycholic acid (TUDCA) ameliorated proteinuria-induced tubulointerstitial lesions and PTC apoptosis in aged mice. Among the three UPR branches, alterations in the inositol-requiring 1α (IRE1α) pathway, but not the activating transcription factor 6 or PERK pathway, were associated with impaired BiP induction in aged kidneys. Moreover, siRNA-mediated suppression of BiP and IRE1α exacerbated free fatty acid-bound albumin-induced apoptosis in cultured PTCs, whereas siRNA-mediated CHOP suppression ameliorated apoptosis. Finally, proteinuria-induced BiP induction in PTCs was diminished in kidney specimens from elderly patients. These results indicate that maladaptive UPRs are involved in proteinuria-induced tubulointerstitial lesions exacerbation in aged kidneys, and that supplementation of chaperones may be used to treat elderly patients with persistent proteinuria. These results should improve understanding of cell vulnerability in aged kidneys.

Topics: Adult; Aged; Aging; Albumins; Animals; Apoptosis; Cells, Cultured; Disease Progression; Endoplasmic Reticulum Chaperone BiP; Endoribonucleases; Heat-Shock Proteins; Humans; Kidney Tubules, Proximal; Male; Mice; Mice, Inbred C57BL; Models, Biological; Molecular Chaperones; Palmitates; Protein Serine-Threonine Kinases; Proteinuria; Signal Transduction; Taurochenodeoxycholic Acid; Transcription Factor CHOP; Unfolded Protein Response

Aortic valve (AV) calcification occurs via a pathophysiological process that includes lipoprotein deposition, inflammation, and osteoblastic differentiation of valvular interstitial cells. Here, we investigated the association between endoplasmic reticulum (ER) stress and AV calcification.. We identified ER stress activation in AV of patients with calcified AV stenosis. We generated an AV calcification model in hypercholesterolemic rabbits and mice, respectively, and found marked AV ER stress induction. Classical ER stress inhibitor, tauroursodeoxycholic acid, administration markedly prevented AV calcification, and attenuated AV osteoblastic differentiation and inflammation in both rabbit and mouse models of AV calcification via inhibition of ER stress. In cultured valvular interstitial cells (VICs), we found that oxidized low density lipoprotein (oxLDL) caused ER stress in a cytosolic [Ca](2+)i-dependent manner. OxLDL promoted osteoblastic differentiation via ER stress-mediated protein kinase-like ER kinase/activating transcription factor 4/osteocalcin and inositol-requiring transmembrane kinase and endonuclease-1α (IRE1α)/spliced X-box-binding protein 1/Runx2 pathway, and induced inflammatory responses through IRE1α/c-Jun N-terminal kinase and IRE1α/nuclear factor kappa-light-chain-enhancer of activated B cells signaling in VICs. Inhibition of ER stress by either tauroursodeoxycholic acid or 4-phenyl butyric acid could both suppress oxLDL-induced osteoblastic differentiation and inflammatory responses in VICs.. These data provide novel evidence that ER stress participates in AV calcification development, and suggest that ER stress may be a novel target for AV calcification prevention and treatment.

Topics: Aged; Animals; Aortic Valve; Aortic Valve Stenosis; Apolipoproteins E; Calcinosis; Calcium; Cell Differentiation; Cells, Cultured; Disease Models, Animal; Endoplasmic Reticulum; Endoplasmic Reticulum Stress; Female; Humans; Hypercholesterolemia; Inflammation; Inflammation Mediators; Intracellular Signaling Peptides and Proteins; Lipoproteins, LDL; Male; Mice; Mice, Knockout; Middle Aged; Osteoblasts; Phenylbutyrates; Rabbits; RNA Interference; Signal Transduction; Swine; Taurochenodeoxycholic Acid; Transfection

Albuminuria contributes to the progression of tubulointerstitial fibrosis. Although it has been demonstrated that ongoing albuminuria leads to tubular injury manifested by the overexpression of numerous proinflammatory cytokines, the mechanism remains largely unknown. In this study, we found that the inflammasome activation which has been recognized as one of the cornerstones of intracellular surveillance system was associated with the severity of albuminuria in the renal biopsies specimens. In vitro, bovine serum albumin (BSA) could also induce the activation of NLRP3 inflammasome in the cultured kidney epithelial cells (NRK-52E). Since there was a significant overlap of NLRP3 with the ER marker calreticulin, the ER stress provoked by BSA seemed to play a crucial role in the activation of inflammasome. Here, we demonstrated that the chemical chaperone taurine-conjugated ursodeoxycholic acid (TUDCA) which was proved to be an enhancer for the adaptive capacity of ER could attenuate the inflammasome activation induced by albuminuria not only in vitro but also in diabetic nephropathy. Taken together, these data suggested that ER stress seemed to play an important role in albuminuria-induced inflammasome activation, elimination of ER stress via TUDCA might hold promise as a novel avenue for preventing inflammasome activation ameliorating kidney epithelial cells injury induced by albuminuria.

Topics: Albuminuria; Animals; Apoptosis; Calreticulin; Carrier Proteins; Cattle; Cells, Cultured; Diabetic Nephropathies; Endoplasmic Reticulum Stress; Epithelial Cells; Gene Expression; Humans; Inflammasomes; Kidney Tubules, Proximal; Mice; NLR Family, Pyrin Domain-Containing 3 Protein; Rats; Serum Albumin, Bovine; Taurochenodeoxycholic Acid

Diabetic retinopathy is one of the most frequent causes of blindness in adults in the Western countries. Although diabetic retinopathy is considered a vascular disease, several reports demonstrate that retinal neurons are also affected, leading to vision loss. Tauroursodeoxycholic acid (TUDCA), an endogenous bile acid, has proven to be neuroprotective in several models of neurodegenerative diseases, including models of retinal degeneration. Since hyperglycemia is considered to play a central role in retinal cell dysfunction and degeneration, underlying the progression of diabetic retinopathy, the purpose of this study was to investigate the neuroprotective effects of TUDCA in rat retinal neurons exposed to elevated glucose concentration. We found that TUDCA markedly decreased cell death in cultured retinal neural cells induced by exposure to elevated glucose concentration. In addition, TUDCA partially prevented the release of apoptosis-inducing factor (AIF) from the mitochondria, as well as the subsequent accumulation of AIF in the nucleus. Biomarkers of oxidative stress, such as protein carbonyl groups and reactive oxygen species production, were markedly decreased after TUDCA treatment as compared to cells exposed to elevated glucose concentration alone. In conclusion, TUDCA protected retinal neural cell cultures from cell death induced by elevated glucose concentration, decreasing mito-nuclear translocation of AIF. The antioxidant properties of TUDCA might explain its cytoprotection. These findings may have relevance in the treatment of diabetic retinopathy patients.

Topics: Animals; Animals, Newborn; Annexin A5; Cell Count; Cell Death; Cell Nucleus; Cells, Cultured; Cholagogues and Choleretics; Glucose; In Situ Nick-End Labeling; Mitochondria; Neurons; Protein Carbonylation; Rats; Rats, Wistar; Retina; Taurochenodeoxycholic Acid

A method of LC-QTOF/MS combining with chemical synthesis has been used to determine the structures of three novel bile acids from bear bile powder. Reference substances of tauroursodeoxycholic acid and taurochenodeoxycholic acid were oxidized by pyridinium chlorochromate. The products were analyzed by LC-QTOF/MS. Total 4 products including 3 isomers were predicted and identified according to the PCC oxidation theory and LC-QTOF/MS results. Bear bile powder samples were dissolved by methanol and analyzed by LC-QTOF/MS. Three unknown peaks were found and identified as 2-[[(3beta, 5beta)-3-hydroxy-7, 24-dioxocholan-24-yl]amino]-ethanesulfonic acid, 2-[[(5beta)-3, 7, 24-trioxocholan-24-yl]amino]-ethanesulfonic acid and 2-[[(5beta, 7beta)-7-hydroxy-3, 24-dioxocholan-24-yl]amino]-ethanesulfonic acid, separately, by matching their results with that of oxidation products above.

Topics: Animals; Bile; Bile Acids and Salts; Chromatography, Liquid; Isomerism; Molecular Structure; Oxidation-Reduction; Powders; Spectrometry, Mass, Electrospray Ionization; Taurochenodeoxycholic Acid; Ursidae

Stress of endoplasmic reticulum (ERS) is one of the molecular triggers of adipocyte dysfunction and chronic low inflammation accompanying obesity. ERS can be alleviated by chemical chaperones from the family of bile acids (BAs). Thus, two BAs currently used to treat cholestasis, ursodeoxycholic and tauroursodeoxycholic acid (UDCA and TUDCA), could potentially lessen adverse metabolic effects of obesity. Nevertheless, BAs effects on human adipose cells are mostly unknown. They could regulate gene expression through pathways different from their chaperone function, namely through activation of farnesoid X receptor (FXR) and TGR5, G-coupled receptor. Therefore, this study aimed to analyze effects of UDCA and TUDCA on human preadipocytes and differentiated adipocytes derived from paired samples of two distinct subcutaneous adipose tissue depots, abdominal and gluteal. While TUDCA did not alter proliferation of cells from either depot, UDCA exerted strong anti-proliferative effect. In differentiated adipocytes, acute exposition to neither TUDCA nor UDCA was able to reduce effect of ERS stressor tunicamycin. However, exposure of cells to UDCA during whole differentiation process decreased expression of ERS markers. At the same time however, UDCA profoundly inhibited adipogenic conversion of cells. UDCA abolished expression of PPARγ and lipogenic enzymes already in the early phases of adipogenesis. This anti-adipogenic effect of UDCA was not dependent on FXR or TGR5 activation, but could be related to ability of UDCA to sustain the activation of ERK1/2 previously linked with PPARγ inactivation. Finally, neither BAs did lower expression of chemokines inducible by TLR4 pathway, when UDCA enhanced their expression in gluteal adipocytes. Therefore while TUDCA has neutral effect on human preadipocytes and adipocytes, the therapeutic use of UDCA different from treating cholestatic diseases should be considered with caution because UDCA alters functions of human adipose cells.

Topics: Adipocytes; Adipogenesis; Cell Differentiation; Cell Proliferation; Cytokines; Endoplasmic Reticulum Stress; Enzyme Activation; Female; Gene Expression Regulation; Humans; Mitogen-Activated Protein Kinase 1; Mitogen-Activated Protein Kinase 3; Subcutaneous Fat; Taurochenodeoxycholic Acid; Ursodeoxycholic Acid

Synapses are considered the earliest site of Alzheimer's disease (AD) pathology, where synapse density is reduced, and synaptic loss is highly correlated with cognitive impairment. Tauroursodeoxycholic acid (TUDCA) has been shown to be neuroprotective in several models of AD, including neuronal exposure to amyloid β (Aβ) and amyloid precursor protein (APP)/presenilin 1 (PS1) double-transgenic mice. Here, we show that TUDCA modulates synaptic deficits induced by Aβ in vitro. Specifically, TUDCA reduced the downregulation of the postsynaptic marker postsynaptic density-95 (PSD-95) and the decrease in spontaneous miniature excitatory postsynaptic currents (mEPSCs) frequency, while increasing the number of dendritic spines. This contributed to the induction of more robust and synaptically efficient neurons, reflected in inhibition of neuronal death. In vivo, TUDCA treatment of APP/PS1 mice abrogated the decrease in PSD-95 reactivity in the hippocampus. Taken together, these results expand the neuroprotective role of TUDCA to a synaptic level, further supporting the use of this molecule as a potential therapeutic strategy for the prevention and treatment of AD.

Topics: Alzheimer Disease; Amyloid beta-Peptides; Amyloid beta-Protein Precursor; Animals; Cell Death; Cerebral Cortex; Disease Models, Animal; Down-Regulation; Hippocampus; Mice; Mice, Transgenic; Neurons; Neuroprotective Agents; Presenilin-1; Rats; Rats, Wistar; Synapses; Taurochenodeoxycholic Acid

Ursodeoxycholic acid, which in vivo is converted to its taurine conjugate tauroursodeoxycholic acid (TUDC), is a mainstay for the treatment of cholestatic liver disease. Earlier work showed that TUDC exerts its choleretic properties in the perfused rat liver in an α5 β1 integrin-mediated way. However, the molecular basis of TUDC-sensing in the liver is unknown. We herein show that TUDC (20 μmol/L) induces in perfused rat liver and human HepG2 cells the rapid appearance of the active conformation of the β1 subunit of α5 β1 integrins, followed by an activating phosphorylation of extracellular signal-regulated kinases. TUDC-induced kinase activation was no longer observed after β1 integrin knockdown in isolated rat hepatocytes or in the presence of an integrin-antagonistic hexapeptide in perfused rat liver. TUDC-induced β1 integrin activation occurred predominantly inside the hepatocyte and required TUDC uptake by way of the Na(+) /taurocholate cotransporting peptide. Molecular dynamics simulations of a 3D model of α5 β1 integrin with TUDC bound revealed significant conformational changes within the head region that have been linked to integrin activation before.. TUDC can directly activate intrahepatocytic β1 integrins, which trigger signal transduction pathways toward choleresis. (HEPATOLOGY 2013).

Topics: Allosteric Regulation; Animals; Dimerization; Green Fluorescent Proteins; Hep G2 Cells; Hepatocytes; Humans; Integrin alpha5beta1; Male; MAP Kinase Signaling System; Oligopeptides; Organic Anion Transporters, Sodium-Dependent; Protein Structure, Secondary; Protein Structure, Tertiary; Rats; Rats, Wistar; RNA, Small Interfering; Structure-Activity Relationship; Symporters; Taurochenodeoxycholic Acid; Taurocholic Acid; Ursodeoxycholic Acid

Endoplasmic reticulum (ER) stress leads to misfolded proteins inside the ER and initiates unfolded protein response (UPR). Unfolded protein response components are involved in pancreatic function and activated during pancreatitis. However, the exact role of ER stress in the exocrine pancreas is unclear. The present study examined the effects of 4-phenylbutyric acid (4-PBA), an ER chaperone, on acini and UPR components.. Rat acini were stimulated with cholecystokinin (10 pmol/L to 10 nmol/L) with or without preincubation of 4-PBA. The UPR components were analyzed, including chaperone-binding protein, protein kinaselike ER kinase, X-box-binding protein 1, c-Jun NH(2)-terminal kinase, CCAAT/enhancer-binding protein homologous protein, caspase 3, and apoptosis. Effects of 4-PBA were measured on secretion, calcium, and trypsin activation.. 4-Phenylbutyric acid led to an increase of secretion, whereas trypsin activation with supraphysiological cholecystokinin was significantly reduced. 4-Phenylbutyric acid prevented chaperone-binding protein up-regulation, diminished protein kinaselike ER kinase, and c-Jun NH2-terminal kinase phosphorylation, prohibited X-box-binding protein 1 splicing and CCAAT/enhancer-binding protein homologous protein expression, caspase 3 activation, and apoptosis caused by supraphysiological cholecystokinin.. By incubation with 4-PBA, beneficial in urea cycle deficiency, it was possible to enhance enzyme secretion to suppress trypsin activation, UPR activation, and proapoptotic pathways. The data hint new perspectives for the use of chemical chaperones in pancreatic diseases.

Topics: Amylases; Animals; Apoptosis; Calcium; Cholecystokinin; Dose-Response Relationship, Drug; Endoplasmic Reticulum Stress; Enzyme Activation; Intracellular Signaling Peptides and Proteins; Male; Pancreas, Exocrine; Phenylbutyrates; Rats; Rats, Wistar; Signal Transduction; Taurochenodeoxycholic Acid; Time Factors; Trypsin; Unfolded Protein Response

Free fatty acids (FFA) can have deleterious effects on β-cells and promote type 2 diabetes, a process known as lipotoxicity. Recently, the induction of endoplasmic reticulum (ER) stress is one mechanism proposed to contribute to the detrimental effects of FFA on β-cells. Tauroursodeoxycholic acid (TUDCA) has been reported to show cytoprotective effects by alleviating ER stress induced by some cytotoxic stimuli. The aim of this study was to investigate the effects of TUDCA on FFA (palmitate)-induced apoptosis and ER stress in rat islet β-cells.. The rat pancreatic β-cell line INS-1 was cultured with palmitate (0.5 mM), or cultured togther with TUDCA (100 μM), Annexin V-fluorescein-isothiocyanate/propidium iodide flow cytometry was used to assess apoptosis in INS-1 cells. Cell viability was evaluated with MTT reduction conversion assay. The expressions of ER stress marker GRP78, ER stress-associated pro-apoptotic effectors CHOP and ATF4 were detected by Western blotting.. TUDCA significantly reduced palmitate-induced cell apoptosis and growth inhibition in INS-1 cells. TUDCA also attenuated palmitate-induced expressions of GRP78, CHOP and ATF4 in INS-1 cells.. Our results thus suggested that TUDCA could protect INS-1 cells from palmitate-induced injury, which might be due to the amelioration of ER stress and blocking the ATF4/CHOP signaling pathway.

Topics: Animals; Apoptosis; Cell Line, Tumor; Cholagogues and Choleretics; Endoplasmic Reticulum Stress; Enzyme Inhibitors; Insulin-Secreting Cells; Molecular Chaperones; Palmitic Acid; Rats; Taurochenodeoxycholic Acid

Alzheimer's disease (AD) is a neurodegenerative disease hallmarked by extracellular Aβ(1-42) containing plaques, and intracellular neurofibrillary tangles (NFT) containing hyperphosphorylated tau protein. Progressively, memory deficits and cognitive disabilities start to occur as these hallmarks affect hippocampus and frontal cortex, regions highly involved in memory. Connective tissue growth factor (CTGF) expression, which is high in the vicinity of Aβ plaques and NFTs, was found to influence γ-secretase activity, the molecular crux in Aβ(1-42) production. Tauroursodeoxycholic acid (TUDCA) is an endogenous bile acid that downregulates CTGF expression in hepatocytes and has been shown to possess therapeutic efficacy in neurodegenerative models. To investigate the possible in vivo therapeutic effects of TUDCA, we provided 0.4% TUDCA-supplemented food to APP/PS1 mice, a well-established AD mouse model. Six months of TUDCA supplementation prevented the spatial, recognition and contextual memory defects observed in APP/PS1 mice at 8 months of age. Furthermore, TUDCA-supplemented APP/PS1 mice displayed reduced hippocampal and prefrontal amyloid deposition. These effects of TUDCA supplementation suggest a novel mechanistic route for Alzheimer therapeutics.

Topics: Alzheimer Disease; Amyloid beta-Protein Precursor; Amyloidogenic Proteins; Animals; Behavior, Animal; Cholagogues and Choleretics; Cognition Disorders; Dietary Supplements; Disease Models, Animal; Male; Mice; Mice, Transgenic; Presenilin-1; Taurochenodeoxycholic Acid

Evidence suggestive of endoplasmic reticulum (ER) stress in the pulmonary arteries of patients with pulmonary arterial hypertension has been described for decades but has never been therapeutically targeted. ER stress is a feature of many conditions associated with pulmonary arterial hypertension like hypoxia, inflammation, or loss-of-function mutations. ER stress signaling in the pulmonary circulation involves the activation of activating transcription factor 6, which, via induction of the reticulin protein Nogo, can lead to the disruption of the functional ER-mitochondria unit and the increasingly recognized cancer-like metabolic shift in pulmonary arterial hypertension that promotes proliferation and apoptosis resistance in the pulmonary artery wall. We hypothesized that chemical chaperones known to suppress ER stress signaling, like 4-phenylbutyrate (PBA) or tauroursodeoxycholic acid, will inhibit the disruption of the ER-mitochondrial unit and prevent/reverse pulmonary arterial hypertension.. PBA in the drinking water both prevented and reversed chronic hypoxia-induced pulmonary hypertension in mice, decreasing pulmonary vascular resistance, pulmonary artery remodeling, and right ventricular hypertrophy and improving functional capacity without affecting systemic hemodynamics. These results were replicated in the monocrotaline rat model. PBA and tauroursodeoxycholic acid improved ER stress indexes in vivo and in vitro, decreased activating transcription factor 6 activation (cleavage, nuclear localization, luciferase, and downstream target expression), and inhibited the hypoxia-induced decrease in mitochondrial calcium and mitochondrial function. In addition, these chemical chaperones suppressed proliferation and induced apoptosis in pulmonary artery smooth muscle cells in vitro and in vivo.. Attenuating ER stress with clinically used chemical chaperones may be a novel therapeutic strategy in pulmonary hypertension with high translational potential.

Topics: Activating Transcription Factor 6; Animals; Antineoplastic Agents; Apoptosis; Cell Proliferation; Cholagogues and Choleretics; Chronic Disease; Disease Models, Animal; Endoplasmic Reticulum Stress; Hypertension, Pulmonary; Hypoxia; Male; Mice; Mice, Inbred C57BL; Mitochondria; Models, Cardiovascular; Phenylbutyrates; Pulmonary Circulation; Rats; Rats, Sprague-Dawley; Signal Transduction; Taurochenodeoxycholic Acid

Endoplasmic reticulum (ER) stress has been recognised as a common pathway in the development of obesity-associated insulin resistance. Protein tyrosine phosphatase 1B (PTP1B) is a negative regulator of insulin signalling and is localised on the ER membrane. The aim of the study was to investigate the cross-talk between ER stress and PTP1B.. Leptin-deficient obese (ob/ob), Ptp1b (also known as Ptpn1) knockout and C57BL/6J mice were subjected to a high-fat or normal-chow diet for 20 weeks. ER stress was induced in cultured myotubes by treatment with tunicamycin. Immunohistochemistry and western blotting were used to assess proteins involved in the ER stress response. Myotube glucose uptake was determined by measuring 2-deoxy[(3)H]glucose incorporation.. A high-fat diet induced ER stress and PTP1B expression in the muscle tissue of mice and these responses were attenuated by treatment with the ER chaperone tauroursodeoxycholic acid (TUDCA). Cultured myotubes exhibited increased levels of PTP1B in response to tunicamycin treatment. Silencing of Ptp1b with small interfering RNA (siRNA) or overexpression of Ptp1b with adenovirus construct failed to alter the levels of ER stress. Ptp1b knockout mice did not differ from the wild-type mice in the extent of tunicamycin-induced upregulation of glucose-regulated protein-78. However, tunicamycin-induced phosphorylation of eukaryotic initiation factor 2α and c-Jun NH(2)-terminal kinase-2 were significantly attenuated in the Ptp1b knockout mice. Treatment with TUDCA or silencing of PTP1B reversed tunicamycin-induced blunted myotube glucose uptake.. Our data suggest that PTP1B is activated by ER stress and is required for full-range activation of ER stress pathways in mediating insulin resistance in the skeletal muscle.

Topics: Animals; Blotting, Western; Cell Line; Diet, High-Fat; Endoplasmic Reticulum Stress; Glucose; Immunohistochemistry; Male; Mice; Mice, Knockout; Muscle Fibers, Skeletal; Protein Tyrosine Phosphatase, Non-Receptor Type 1; Real-Time Polymerase Chain Reaction; Taurochenodeoxycholic Acid

The endoplasmic reticulum (ER) plays a critical role in ensuring proper folding of newly synthesized proteins. Aberrant ER stress is reported to play a causal role in cardiovascular diseases. However, the effects of ER stress on vascular smooth muscle contractility and blood pressure remain unknown. The aim of this study was to investigate whether aberrant ER stress causes abnormal vasoconstriction and consequent high blood pressure in mice.. ER stress markers, vascular smooth muscle contractility, and blood pressure were monitored in mice. Incubation of isolated aortic rings with tunicamycin or MG132, 2 structurally unrelated ER stress inducers, significantly increased both phenylephrine-induced vasoconstriction and the phosphorylation of myosin light chain (Thr18/Ser19), both of which were abrogated by pretreatment with chemical chaperones or 5-Aminoimidazole-4-carboxamide ribonucleotide and metformin, 2 potent activators for the AMP-activated protein kinase. Consistently, administration of tauroursodeoxycholic acid or 4-phenyl butyric acid, 2 structurally unrelated chemical chaperones, in AMP-activated protein kinase-α2 knockout mice lowered blood pressure and abolished abnormal vasoconstrictor response of AMP-activated protein kinase-α2 knockout mice to phenylephrine. Consistently, tunicamycin (0.01 μg/g per day) infusion markedly increased both systolic and diastolic blood pressure, both of which were ablated by coadministration of 4-phenyl butyric acid. Furthermore, 4-phenyl butyric acid or tauroursodeoxycholic acid, which suppressed angiotensin II infusion-induced ER stress markers in vivo, markedly lowered blood pressure in angiotensin II-infused mice in vivo.. We conclude that ER stress increases vascular smooth muscle contractility resulting in high blood pressure, and AMP-activated protein kinase activation mitigates high blood pressure through the suppression of ER stress in vivo.

Topics: Aminoimidazole Carboxamide; AMP-Activated Protein Kinases; Angiotensin II; Animals; Antihypertensive Agents; Blood Pressure; Cells, Cultured; Disease Models, Animal; Dose-Response Relationship, Drug; Endoplasmic Reticulum Stress; Enzyme Activation; Enzyme Activators; Humans; Hypertension; Leupeptins; Mice; Mice, Knockout; Muscle, Smooth, Vascular; Myosin Light Chains; Nitric Oxide Synthase Type III; Phenylbutyrates; Phenylephrine; Phosphorylation; Ribonucleotides; Taurochenodeoxycholic Acid; Time Factors; Tunicamycin; Vasoconstriction; Vasoconstrictor Agents

In obesity and diabetes, adipocytes show significant endoplasmic reticulum (ER) stress. Hyperglycemia-induced ER stress has not been studied in adipocyte differentiation and adipokine expression. Taurine has been known to protect the cells against ER stress. This study examined the effect of taurine on ER stress-induced adipocyte differentiation and adipokine expression to explain the therapeutic effect of taurine on diabetes and obesity. To do this, human preadipocytes were differentiated into adipocytes, in the presence or absence of taurine, under ER stress conditions. Changes in adipokine expression in adipocytes stimulated with IL-1β were investigated in the presence or absence of taurine. Human preadipocytes were treated with thapsigargin (10 nM) or high glucose concentrations (100 mM) as ER stress inducers during differentiation into adipocytes. Thapsigargin inhibited the differentiation of adipocytes in a dose-dependent manner, but the high glucose concentration treatment did not. Taurine 100 mM treatment did not block the inhibition of differentiation of preadipcytes into adipocytes. Furthermore, the high glucose concentration treatment inhibited the expression of adiponectin and increased the expression of leptin in human adipocytes. However, taurine treatment did not affect the expression of two adipokines. In conclusion, the therapeutic mechanism of taurine in diabetes and obesity does not appear to occur by alleviating hyperglycemia-mediated ER stress. To clarify the molecular mechanism by which taurine improves diabetic symptoms and obesity in animal models, the protective effect of taurine against hyperglycemia- or overnutrition-mediated ER stress should be further evaluated under various conditions or types of ER stress.

Topics: Acetylcysteine; Adipocytes; Adiponectin; Cell Differentiation; Endoplasmic Reticulum Stress; Humans; Hyperglycemia; Leptin; Taurine; Taurochenodeoxycholic Acid; Thapsigargin

Biliary lipid secretion plays an important role in gallstone disease and reverse cholesterol transport (RCT). Using Sr-bI/Abcg5 double knockout mice (dko), the present study investigated the differential contribution of two of the most relevant transporters: adenosine triphosphate (ATP)-binding cassette subfamily G member 5 and 8 (ABCG5/G8) and scavenger receptor class B type I (SR-BI) to sterol metabolism and RCT. Plasma cholesterol levels increased in the following order, mainly due to differences in high density lipoprotein (HDL): Abcg5 ko < wild type < Sr-bI/Abcg5 dko < Sr-bI ko. Liver cholesterol content was elevated in Sr-bI ko only (P < 0.05). In Sr-bI/Abcg5 dko plasma plant sterols were highest, while hepatic plant sterols were lower compared with Abcg5 ko (P < 0.05). Under baseline conditions, biliary cholesterol secretion rates decreased in the following order: wild type > Sr-bI ko (-16%) > Abcg5 ko (-75%) > Sr-bI/Abcg5 dko (-94%), all at least P < 0.05, while biliary bile acid secretion did not differ between groups. However, under supraphysiological conditions, upon infusion with increasing amounts of the bile salt tauroursodeoxycholic acid, Abcg5 became fully rate-limiting for biliary cholesterol secretion. Additional in vivo macrophage-to-feces RCT studies demonstrated an almost 50% decrease in overall RCT in Sr-bI/Abcg5 dko compared with Abcg5 ko mice (P < 0.01).. These data demonstrate that (1) SR-BI contributes to ABCG5/G8-independent biliary cholesterol secretion under basal conditions; (2) biliary cholesterol mass secretion under maximal bile salt-stimulated conditions is fully dependent on ABCG5/G8; and (3) Sr-bI contributes to macrophage-to-feces RCT independent of Abcg5/g8.

Topics: Animals; ATP Binding Cassette Transporter, Subfamily G, Member 5; ATP Binding Cassette Transporter, Subfamily G, Member 8; ATP-Binding Cassette Transporters; Biliary Tract; Cholesterol; Lipoproteins; Liver; Mice; Mice, Knockout; Phytosterols; Scavenger Receptors, Class B; Taurochenodeoxycholic Acid

p63, the structural and functional homologue of p53, is expressed either as a full-length isoform, containing a transactivation (TA) domain (TAp63), or as a truncated isoform, which lacks TA (ΔNp63). Amyloid-β (Aβ) incubation of neuronal cells results in stress-induced cell death through poorly understood mechanisms. We investigated the role of p63 in Aβ-induced stress. Our results show that Aβ-induced apoptosis of rat PC12 neuronal-like cells and primary cortical neurons was associated with stabilization of pro-apoptotic TAp63 and, most importantly, degradation of anti-apoptotic ΔNp63 through a MAPK- and proteasome-dependent mechanism. This was associated with increased c-Jun, and partially modulated by tauroursodeoxycholic acid. As expected, classic genotoxic insults resulted in c-Jun upregulation and concomitant ΔNp63 reduction. Endogenous and ectopic ΔNp63 expression was also markedly reduced by c-Jun overexpression. Further, Aβ-mediated ΔNp63 degradation occurred in a c-Jun-dependent manner. Downregulation of c-Jun expression by specific c-Jun siRNA abrogated the reduction of ΔNp63 levels following Aβ insult, whereas overexpression of c-Jun led to its degradation. c-Jun significantly decreased ΔNp63 half-life. Together, these findings demonstrate that the abundance of anti-apoptotic ΔNp63 in response to Aβ-induced cell stress is regulated by a c-Jun-dependent mechanism, and highlight the importance of finding novel targets for potential therapeutic intervention.

Topics: Amyloid beta-Peptides; Animals; Apoptosis; Cells, Cultured; Cerebral Cortex; Embryo, Mammalian; Enzyme Inhibitors; Gene Expression Regulation; Half-Life; Mice; Mitogen-Activated Protein Kinase Kinases; Neurons; PC12 Cells; Proteasome Endopeptidase Complex; Protein Structure, Tertiary; Proto-Oncogene Proteins c-jun; Rats; RNA, Small Interfering; Taurochenodeoxycholic Acid; Time Factors; Transcription Factors; Transcriptional Activation; Transfection; Tumor Suppressor Proteins

Endoplasmic reticulum (ER) stress and inflammation are important mechanisms that underlie many of the serious consequences of type II diabetes. However, the role of ER stress and inflammation in impaired ischaemia-induced neovascularization in type II diabetes is unknown. We studied ischaemia-induced neovascularization in the hind-limb of 4-week-old db - /db- mice and their controls treated with or without the ER stress inhibitor (tauroursodeoxycholic acid, TUDCA, 150 mg/kg per day) and interleukin-1 receptor antagonist (anakinra, 0.5 µg/mouse per day) for 4 weeks. Blood pressure was similar in all groups of mice. Blood glucose, insulin levels, and body weight were reduced in db - /db- mice treated with TUDCA. Increased cholesterol and reduced adiponectin in db - /db- mice were restored by TUDCA and anakinra treatment. ER stress and inflammation in the ischaemic hind-limb in db - /db- mice were attenuated by TUDCA and anakinra treatment. Ischaemia-induced neovascularization and blood flow recovery were significantly reduced in db - /db- mice compared to control. Interestingly, neovascularization and blood flow recovery were restored in db - /db- mice treated with TUDCA or anakinra compared to non-treated db - /db- mice. TUDCA and anakinra enhanced eNOS-cGMP, VEGFR2, and reduced ERK1/2 MAP-kinase signalling, while endothelial progenitor cell number was similar in all groups of mice. Our findings demonstrate that the inhibition of ER stress and inflammation prevents impaired ischaemia-induced neovascularization in type II diabetic mice. Thus, ER stress and inflammation could be potential targets for a novel therapeutic approach to prevent impaired ischaemia-induced vascular pathology in type II diabetes.

Topics: Animals; Anti-Inflammatory Agents; Biomarkers; Blood Vessels; Diabetes Mellitus, Type 2; Diabetic Angiopathies; Disease Models, Animal; Endoplasmic Reticulum; Endoplasmic Reticulum Stress; Hindlimb; Interleukin 1 Receptor Antagonist Protein; Ischemia; Macrophages; Mice; Mice, Inbred C57BL; Muscle, Skeletal; Neovascularization, Physiologic; Recovery of Function; Regional Blood Flow; Signal Transduction; Taurochenodeoxycholic Acid; Time Factors

To evaluate and compare the protective effect of tauroursodeoxycholic acid (TUDCA) on photoreceptor degeneration in different models of retinal degeneration (RD) in mice.. Bbs(M390R/M390R) mice were injected subcutaneously twice a week, from P40 to P120, and rd10 mice were injected every 3 days from P6 to P38 with TUDCA or vehicle (0.15 M NaHCO(3)). Rd1 and rd16 mice were injected daily from P6 to P30 with TUDCA or vehicle. Retinal structure and function were determined at multiple time points by electroretinography (ERG), optical coherence tomography (OCT), and histology.. The amplitude of ERG b-waves was significantly higher in TUDCA-treated Bbs1 and rd10 animals than in controls. Retinal thickness on OCT was slightly greater in treated Bbs1 animals than in the controls. Histologically, outer segments were preserved, and the outer nuclear layer was significantly thicker in the treated Bbs1 and rd10 mice than in the controls. Bbs1(M390R/M390R) mice developed less obesity than the control Bbs1(M390R/M390R) while receiving TUDCA. The Rd1 and rd16 mice showed no improvement with TUDCA treatment, and the rd1 mice did not have normal weight gain during treatment.. TUDCA treatment preserved ERG b-waves and the outer nuclear layer in Bbs1(M390R/M390R) mice, and prevented obesity assessed at P120. TUDCA treatment preserved ERG b-waves and the outer nuclear layer in the rd10 mice to P30. TUDCA is a prime candidate for treatment of humans with retinal degeneration, especially those with Bardet-Biedl syndrome, whom it may help not only with the vision loss, but with the debilitating obesity as well.

Topics: Animals; Bardet-Biedl Syndrome; Cholagogues and Choleretics; Disease Models, Animal; Electroretinography; Injections, Subcutaneous; Mice; Microtubule-Associated Proteins; Obesity; Retina; Retinal Degeneration; Retinitis Pigmentosa; Taurochenodeoxycholic Acid; Tomography, Optical Coherence

Apoptosis is an important determinant of the normal development of pre-implantation embryos in vitro. Recently, endoplasmic reticulum (ER) stress-mediated apoptosis has been extensively investigated in a wide variety of diseases. Efficient functioning of the ER is essential for most cellular activities and survival. Tauroursodeoxycholic acid (TUDCA), an endogenous bile acid, has been reported to attenuate ER stress-mediated cell death by interrupting the classic pathways of apoptosis. Therefore, in this study, the anti-apoptotic effect of TUDCA on ER stress-induced apoptosis was examined in pre-implantation pig embryos. Also, tunicamycin was used to investigate the effects of ER stress on pig embryo development. After in vitro maturation and fertilization, presumptive pig embryos were cultured in NCSU-23 medium supplemented with TUDCA or TM for 6 days at 39 °C, 5% CO(2) in air. All data were analysed using one-way anova and Duncan's multiple range test in the statistical analysis system (SAS). In addition, we also determined the optimal TM and TUDCA concentrations. Samples were treated with TM at concentrations of 0, 1, 2 or 5 μm and with TUDCA at concentrations of 0, 100, 200 or 300 μm. When TM was used during in vitro culture, only 8.2% (8/97) of the embryos developed to the blastocyst stage when the treatment concentration was 1 μm compared with 27.4% (28/102) of the embryos in the control group (p < 0.05). In contrast, the frequency of blastocyst formation and the number of cells were higher when treated with 200 μm TUDCA compared with the control group (32.8% and 39.5 vs 22.2% and 35.6, p < 0.05). Moreover, the developmental rate to the blastocyst stage embryo in the group treated with TM and TUDCA was not significantly different from that of the control group (17.8%, 26/142 vs 24.9%, 36/145). Furthermore, the blastocyst cell number was enhanced (31.9 vs 36.9) and apoptosis reduced (TUNEL-positive nuclei number, 6.0 vs 3.2) by TUDCA treatment in pig embryos. In the real-time quantitative RT-PCR analysis, the expression of anti-apoptotic Bcl-XL gene was shown to be increased in the blastocyst stage because of TUDCA treatment, whereas expression of pro-apoptotic Bax was decreased. In addition, we also found that TUDCA decreased the rate of TM-induced apoptosis in the pre-implantation stage. Taken together, our results indicate that TUDCA improves the developmental competence of pig embryos by modulating ER stress-induced apoptosis during the pre-implan

Topics: Animals; Apoptosis; Blastocyst; Cells, Cultured; Embryo Culture Techniques; Embryonic Development; Endoplasmic Reticulum Stress; Female; Fertilization in Vitro; In Situ Nick-End Labeling; Oocytes; RNA, Messenger; Sus scrofa; Taurochenodeoxycholic Acid; Tunicamycin

Endoplasmic reticulum (ER) stress is proposed as a novel link between elevated fatty acids levels, obesity and insulin resistance in liver and adipose tissue. However, it is unknown whether ER stress also contributes to lipid-induced insulin resistance in skeletal muscle, the major tissue responsible of insulin-stimulated glucose disposal. Here, we investigated the possible role of ER stress in palmitate-induced alterations of insulin action, both in vivo, in gastrocnemius of high-palm diet fed mice, and in vitro, in palmitate-treated C(2)C(12) myotubes. We demonstrated that 8 weeks of high-palm diet increased the expression of ER stress markers in muscle of mice, whereas ex-vivo insulin-stimulated PKB phosphorylation was not altered in this tissue. In addition, exposure of C(2)C(12) myotubes to either tuncamycine or palmitate induced ER stress and altered insulin-stimulated PKB phosphorylation. However, alleviation of ER stress by either TUDCA or 4-PBA treatments, or by overexpressing Grp78, did not restore palmitate-induced reduction of insulin-stimulated PKB phosphorylation in C(2)C(12) myotubes. This work highlights that, even ER stress is associated with palmitate-induced alterations of insulin signaling, ER stress is likely not the major culprit of this effect in myotubes, suggesting that the previously proposed link between ER stress and insulin resistance is less important in skeletal muscle than in adipose tissue and liver.

Topics: Animals; Butylamines; Diet; Dietary Fats; Endoplasmic Reticulum Chaperone BiP; Endoplasmic Reticulum Stress; Heat-Shock Proteins; Insulin; Insulin Resistance; Male; Mice; Mice, Inbred C57BL; Muscle Fibers, Skeletal; Palmitates; Taurochenodeoxycholic Acid; Tunicamycin

X-box-binding protein 1 (XBP1) is an important regulator of a subset of genes active during endoplasmic reticulum (ER) stress. In the present study, we analyzed XBP1 level and location to explore the effect of ER stress on oocyte maturation and developmental competency of porcine embryos in an in vitro culture system. First, we examined the localization of XBP1 at different meiotic stages of porcine oocytes and at early stages of parthenogenetic embryo development. Fluorescence staining showed that expression of functional XBP1 was weak in mature oocytes and at the 1-, 2-, and 8-cell stages of embryos but abundant at the germinal vesicle (GV), 4-cell, morula, and blastocyst stages. In addition, RT-PCR revealed that both spliced XBP1 (XBP1-s) and unspliced XBP1 (XBP1-u) were expressed at the GV, 4-cell, morula, and blastocyst stages. Tunicamycin, an ER stress inducer, induced active XBP1 protein in nuclei of 4-cell embryos. Next, porcine embryos cultured in the presence of tauroursodeoxycholate, an ER stress inhibitor, were studied. Total cell numbers and the extent of the inner cell mass increased (P < 0.05), whereas the rate of nuclear apoptosis decreased (P < 0.05). Moreover, expression of the antiapoptotic gene BCL2 increased, whereas expression of the proapoptotic genes BCL2L1 (Bcl-xl) and TP53 decreased. The results indicated that inhibition of ER stress enhanced porcine oocyte maturation and embryonic development by preventing ER stress-mediated apoptosis in vitro.

Topics: Animals; Apoptosis; DNA-Binding Proteins; Embryo, Mammalian; Embryonic Development; Endoplasmic Reticulum Stress; Gene Expression Profiling; Oocytes; Oogenesis; Parthenogenesis; Regulatory Factor X Transcription Factors; Reverse Transcriptase Polymerase Chain Reaction; Swine; Taurochenodeoxycholic Acid; Transcription Factors; Tunicamycin

Known therapies for influenza A virus infection are complicated by the frequent emergence of resistance. A therapeutic strategy that may escape viral resistance is targeting host cellular mechanisms involved in viral replication and pathogenesis. The endoplasmic reticulum (ER) stress response, also known as the unfolded protein response (UPR), is a primitive, evolutionary conserved molecular signaling cascade that has been implicated in multiple biological phenomena including innate immunity and the pathogenesis of certain viral infections. We investigated the effect of influenza A viral infection on ER stress pathways in lung epithelial cells. Influenza A virus induced ER stress in a pathway-specific manner. We showed that the virus activates the IRE1 pathway with little or no concomitant activation of the PERK and the ATF6 pathways. When we examined the effects of modulating the ER stress response on the virus, we found that the molecular chaperone tauroursodeoxycholic acid (TUDCA) significantly inhibits influenza A viral replication. In addition, a specific inhibitor of the IRE1 pathway also blocked viral replication. Our findings constitute the first evidence that ER stress plays a role in the pathogenesis of influenza A viral infection. Decreasing viral replication by modulating the host ER stress response is a novel strategy that has important therapeutic implications.

Topics: Activating Transcription Factor 6; Antiviral Agents; Cells, Cultured; eIF-2 Kinase; Endoplasmic Reticulum Stress; Endoribonucleases; Humans; Influenza A virus; Influenza, Human; Membrane Proteins; Molecular Chaperones; Protein Serine-Threonine Kinases; Taurochenodeoxycholic Acid; Virus Replication

The incidence of acute kidney injury (AKI) is very high, and multiple physiopathological processes are involved, including endoplasmic reticulum stress (ERS). Tauroursodeoxycholic acid (TUDCA) is an endogenous bile acid derivative that has been reported to inhibit ERS. To determine whether TUDCA had a nephroprotective effect on AKI and to explore the exact mechanism, an ischaemia/reperfusion (I/R)-induced AKI mouse model and a tunicamycin-pre-treated TCMK-1 cell model were established. It was found that the renal tubular necrosis score and cell apoptosis index reached their peak 24 hr after I/R. GRP78 and C/EBP homologous protein (CHOP) expression and Caspase 12 activation were enhanced, reaching their peaks at 4 and 12 hr, respectively. TUDCA intervention not only decreased the renal tubular necrosis score and the cell apoptosis index but also down-regulated GRP78 and CHOP expression and Caspase 12 activation. The survival rate of TCMK-1 cells pre-treated with TUDCA was significantly higher than that of TCMK-1 cells without TUDCA pre-treatment. In conclusion, TUDCA had a nephroprotective effect on IR-induced AKI by inhibiting ERS and by blocking GRP78 and CHOP expression, reducing Caspase 12 activation and inhibiting cell apoptosis.

Topics: Acute Kidney Injury; Animals; Apoptosis; Caspase 12; Cells, Cultured; Disease Models, Animal; Down-Regulation; Endoplasmic Reticulum Chaperone BiP; Endoplasmic Reticulum Stress; Heat-Shock Proteins; Male; Mice; Mice, Inbred C57BL; Reperfusion Injury; Stress, Physiological; Taurochenodeoxycholic Acid; Transcription Factor CHOP

Chemoprevention would be a desirable strategy to avoid duodenectomy in patients with familial adenomatous polyposis (FAP) suffering from duodenal adenomatosis. We investigated the in vitro effects on cell proliferation, apoptosis, and COX-2 expression of the potential chemopreventives celecoxib and tauro-ursodeoxycholic acid (UDCA). HT-29 colon cancer cells and LT97 colorectal micro-adenoma cells derived from a patient with FAP, were exposed to low dose celecoxib and UDCA alone or in combination with tauro-cholic acid (CA) and tauro-chenodeoxycholic acid (CDCA), mimicking bile of FAP patients treated with UDCA. In HT-29 cells, co-treatment with low dose celecoxib and UDCA resulted in a decreased cell growth (14-17%, p<0.01). A more pronounced decrease (23-27%, p<0.01) was observed in LT97 cells. Cell growth of HT-29 cells exposed to 'artificial bile' enriched with UDCA, was decreased (p<0.001), either in the absence or presence of celecoxib. In LT97 cells incubated with 'artificial bile' enriched with UDCA, cell growth was decreased only in the presence of celecoxib (p<0.05). No clear evidence was found for involvement of proliferating cell nuclear antigen, caspase-3, or COX-2 in the cellular processes leading to the observed changes in cell growth. In conclusion, co-treatment with low dose celecoxib and UDCA has growth inhibitory effects on colorectal adenoma cells derived from a patient with FAP, and further research on this combination as promising chemopreventive strategy is desired.

Topics: Adenoma; Adenomatous Polyposis Coli; Antineoplastic Combined Chemotherapy Protocols; Apoptosis; Celecoxib; Cell Line, Tumor; Cell Proliferation; Cholagogues and Choleretics; Colonic Neoplasms; Cyclooxygenase 2 Inhibitors; HT29 Cells; Humans; Pyrazoles; Sulfonamides; Taurochenodeoxycholic Acid

Endoplasmic reticulum (ER) stress has been implicated in glucose-induced beta cell dysfunction. However, its causal role has not been established in vivo. Our objective was to determine the causal role of ER stress and its link to oxidative stress in glucose-induced beta cell dysfunction in vivo.. Healthy Wistar rats were infused i.v. with glucose for 48 h to achieve 20 mmol/l hyperglycaemia with or without the co-infusion of the superoxide dismutase mimetic tempol (TPO), or the chemical chaperones 4-phenylbutyrate (PBA) or tauroursodeoxycholic acid (TUDCA). This was followed by assessment of beta cell function and measurement of ER stress markers and superoxide in islets.. Glucose infusion for 48 h increased mitochondrial superoxide and ER stress markers and impaired beta cell function. Co-infusion of TPO, which we previously found to reduce mitochondrial superoxide and prevent glucose-induced beta cell dysfunction, reduced ER stress markers. Similar to findings with TPO, co-infusion of PBA, which decreases mitochondrial superoxide, prevented glucose-induced beta cell dysfunction in isolated islets. TUDCA was also effective. Also similar to findings with TPO, PBA prevented beta cell dysfunction during hyperglycaemic clamps in vivo and after hyperglycaemia (15 mmol/l) for 96 h.. Here, we causally implicate ER stress in hyperglycaemia-induced beta cell dysfunction in vivo. We show that: (1) there is a positive feedback cycle between oxidative stress and ER stress in glucose-induced beta cell dysfunction, which involves mitochondrial superoxide; and (2) this cycle can be interrupted by superoxide dismutase mimetics as well as chemical chaperones, which are of potential interest to preserve beta cell function in type 2 diabetes.

Topics: Animals; Antioxidants; Cyclic N-Oxides; Endoplasmic Reticulum Stress; Female; Glucose; Hyperglycemia; Insulin-Secreting Cells; Mitochondria; Oxidative Stress; Phenylbutyrates; Rats; Rats, Wistar; Spin Labels; Superoxides; Taurochenodeoxycholic Acid

Alzheimer's disease (AD) is a neurodegenerative disorder characterized by accumulation of amyloid-β (Aβ) peptide in the hippocampus and frontal cortex of the brain, leading to progressive cognitive decline. The endogenous bile acid tauroursodeoxycholic acid (TUDCA) is a strong neuroprotective agent in several experimental models of disease, including neuronal exposure to Aβ. Nevertheless, the therapeutic role of TUDCA in AD pathology has not yet been ascertained. Here we report that feeding APP/PS1 double-transgenic mice with diet containing 0.4 % TUDCA for 6 months reduced accumulation of Aβ deposits in the brain, markedly ameliorating memory deficits. This was accompanied by reduced glial activation and neuronal integrity loss in TUDCA-fed APP/PS1 mice compared to untreated APP/PS1 mice. Furthermore, TUDCA regulated lipid-metabolism mediators involved in Aβ production and accumulation in the brains of transgenic mice. Overall amyloidogenic APP processing was reduced with TUDCA treatment, in association with, but not limited to, modulation of γ-secretase activity. Consequently, a significant decrease in Aβ(1-40) and Aβ(1-42) levels was observed in both hippocampus and frontal cortex of TUDCA-treated APP/PS1 mice, suggesting that chronic feeding of TUDCA interferes with Aβ production, possibly through the regulation of lipid-metabolism mediators associated with APP processing. These results highlight TUDCA as a potential therapeutic strategy for the prevention and treatment of AD.

Topics: Alzheimer Disease; Amyloid beta-Peptides; Amyloid beta-Protein Precursor; Animals; Astrocytes; Bile Acids and Salts; Brain; Cognition Disorders; DNA-Binding Proteins; Humans; Lipid Metabolism; Mice; Mice, Transgenic; Microglia; Nerve Tissue Proteins; Neurons; Nuclear Proteins; Presenilin-1; Protein Processing, Post-Translational; Synucleins; Taurochenodeoxycholic Acid

Mutations in either retinoid isomerase (RPE65) or lecithin-retinol acyltransferase (LRAT) lead to Leber congenital amaurosis (LCA). By using the Lrat(-/-) mouse model, previous studies have shown that the rapid cone degeneration in LCA was caused by endoplasmic reticulum (ER) stress induced by S-opsin aggregation. The purpose of this study is to examine the efficacy of an ER chemical chaperone, tauroursodeoxycholic acid (TUDCA), in preserving cones in the Lrat(-/-) model.. Lrat(-/-) mice were systemically administered with TUDCA and vehicle (0.15 M NaHCO(3)) every 3 days from P9 to P28. Cone cell survival was determined by counting cone cells on flat-mounted retinas. The expression and subcellular localization of cone-specific proteins were analyzed by western blotting and immunohistochemistry, respectively.. TUDCA treatment reduced ER stress and apoptosis in Lrat(-/-) retina. It significantly slowed down cone degeneration in Lrat(-/-) mice, resulting in a ∼3-fold increase in cone density in the ventral and central retina as compared with the vehicle-treated mice at P28. Furthermore, TUDCA promoted the degradation of cone membrane-associated proteins by enhancing the ER-associated protein degradation pathway.. Systemic injection of TUDCA is effective in reducing ER stress, preventing apoptosis, and preserving cones in Lrat(-/-) mice. TUDCA has the potential to lead to the development of a new class of therapeutic drugs for treating LCA.

Topics: Animals; Antiviral Agents; Apoptosis; Blotting, Western; Cell Count; Cell Survival; Cone Opsins; Disease Models, Animal; Electroretinography; Endoplasmic Reticulum; Immunohistochemistry; Injections, Subcutaneous; Isomerism; Leber Congenital Amaurosis; Mice; Mice, Inbred BALB C; Retinal Cone Photoreceptor Cells; Taurochenodeoxycholic Acid

Endoplasmic reticulum (ER) stress has been implicated in the pathogenesis of nonalcoholic steatohepatitis. The ER stress response is activated in the livers of mice fed a methionine- and choline-deficient (MCD) diet, yet the role of ER stress in the pathogenesis of MCD diet-induced steatohepatitis is unknown. Using chemical chaperones on hepatic steatosis and markers of inflammation and fibrosis in mice fed a MCD diet, we aim to determine the effects of reducing ER stress. C57BL/6J mice were fed a MCD diet with or without the ER chemical chaperones 4-phenylbutyric acid (PBA) and tauroursodeoxycholic acid (TUDCA) for 2 wk. TUDCA and PBA effectively attenuated the ER stress response in MCD diet-fed mice, as evidenced by reduced protein levels of phosphorylated eukaryotic initiation factor 2α and phosphorylated JNK and suppression of mRNA levels of CCAAT/enhancer binding protein homologous protein, glucose-regulated protein 78 kDa, and X-box binding protein 1. However, PBA and TUDCA did not decrease MCD diet-induced hepatic steatosis. MCD diet-induced hepatic inflammation, as evidenced by increased plasma alanine aminotransferase and induction of hepatic TNFα expression, was also not reduced by PBA or TUDCA. PBA and TUDCA did not attenuate MCD diet-induced upregulation of the fibrosis-associated genes tissue inhibitor of metalloproteinase-1 and matrix metalloproteinase-9. ER chemical chaperones reduce MCD diet-induced ER stress, yet they do not improve MCD diet-induced hepatic steatosis, inflammation, or activation of genes associated with fibrosis. These data suggest that although the ER stress response is activated by the MCD diet, it does not have a primary role in the pathogenesis of MCD diet-induced steatohepatitis.

Topics: Animals; Blood Glucose; Blotting, Western; Body Weight; Cholesterol; Choline Deficiency; Diet; Endoplasmic Reticulum; Fatty Liver; Gene Expression; Inflammation; Liver; Liver Cirrhosis; Male; Methionine; Mice; Mice, Inbred C57BL; Molecular Chaperones; Phenylbutyrates; Real-Time Polymerase Chain Reaction; Stress, Physiological; Taurochenodeoxycholic Acid

Toxin A (TcdA) and toxin B (TcdB) are the major virulence factors of Clostridium difficile-associated diarrhoea (CDAD). TcdA and TcdB mono-glucosylate small GTPases of the Rho family, thereby causing actin re-organisation in colonocytes, resulting in the loss of colonic barrier function. The hydrophilic bile acid tauroursodeoxycholic acid (TUDCA) is an approved drug for the treatment of cholestasis and biliary cirrhosis. In this study, TUDCA-induced activation of Akt1 is presented to increase cellular levels of pS71-Rac1/Cdc42 in human hepatocarcinoma (HepG2) cells, showing for the first time that bile acid signalling affects the activity of Rho proteins. Rac1/Cdc42 phosphorylation, in turn, protects Rac1/Cdc42 from TcdB-catalysed glucosylation and reduces the TcdB-induced cytopathic effects in HepG2 cells. The results of this study indicate that TUDCA may prove useful as a therapeutic agent for the treatment of CDAD.

Topics: Bacterial Proteins; Bacterial Toxins; Biocatalysis; cdc42 GTP-Binding Protein; Clostridioides difficile; Dose-Response Relationship, Drug; Glycosylation; Humans; Phosphorylation; rac1 GTP-Binding Protein; Taurochenodeoxycholic Acid; Tumor Cells, Cultured

Epidermal growth factor receptor tyrosine kinase (EGFRtk) and endoplasmic reticulum (ER) stress are important factors in cardiovascular complications. Understanding whether enhanced EGFRtk activity and ER stress induction are involved in cardiac damage, and microvascular dysfunction in type 1 diabetes mellitus is an important question that has remained unanswered. Cardiac fibrosis and microvascular function were determined in C57BL/6J mice injected with streptozotocin only or in combination with EGFRtk inhibitor (AG1478), ER stress inhibitor (Tudca), or insulin for 2 weeks. In diabetic mice, we observed an increase in EGFRtk phosphorylation and ER stress marker expression (CHOP, ATF4, ATF6, and phosphorylated-eIF2α) in heart and mesenteric resistance arteries, which were reduced with AG1478, Tudca, and insulin. Cardiac fibrosis, enhanced collagen type I, and plasminogen activator inhibitor 1 were decreased with AG1478, Tudca, and insulin treatments. The impaired endothelium-dependent relaxation and -independent relaxation responses were also restored after treatments. The inhibition of NO synthesis reduced endothelium-dependent relaxation in control and treated streptozotocin mice, whereas the inhibition of NADPH oxidase improved endothelium-dependent relaxation only in streptozotocin mice. Moreover, in mesenteric resistance arteries, the mRNA levels of Nox2 and Nox4 and the NADPH oxidase activity were augmented in streptozotocin mice and reduced with treatments. This study unveiled novel roles for enhanced EGFRtk phosphorylation and its downstream ER stress in cardiac fibrosis and microvascular endothelial dysfunction in type 1 diabetes mellitus.

Topics: Animals; Blotting, Western; Cholagogues and Choleretics; Diabetes Mellitus, Type 1; Endoplasmic Reticulum Stress; ErbB Receptors; Fibrosis; Gene Expression; Heart; Hypoglycemic Agents; Insulin; Male; Mice; Mice, Inbred C57BL; Myocardium; Phosphorylation; Quinazolines; Reverse Transcriptase Polymerase Chain Reaction; Streptozocin; Taurochenodeoxycholic Acid; Transcription Factor CHOP; Tyrphostins; Vasodilation

Apolipoprotein (apo) E4 is a major genetic risk factor for a wide spectrum of inflammatory metabolic diseases, including atherosclerosis, diabetes, and Alzheimer disease. This study compared diet-induced adipose tissue inflammation as well as functional properties of macrophages isolated from human APOE3 and APOE4 mice to identify the mechanism responsible for the association between apoE4 and inflammatory metabolic diseases. The initial study confirmed previous reports that APOE4 gene replacement mice were less sensitive than APOE3 mice to diet-induced body weight gain but exhibited hyperinsulinemia, and their adipose tissues were similarly inflamed as those in APOE3 mice. Peritoneal macrophages isolated from APOE4 mice were defective in efferocytosis compared with APOE3 macrophages. Increased cell death was also observed in APOE4 macrophages when stimulated with LPS or oxidized LDL. Western blot analysis of cell lysates revealed that APOE4 macrophages displayed elevated JNK phosphorylation indicative of cell stress even under basal culturing conditions. Significantly higher cell stress due mainly to potentiation of endoplasmic reticulum (ER) stress signaling was also observed in APOE4 macrophages after LPS and oxidized LDL activation. The defect in efferocytosis and elevated apoptosis sensitivity of APOE4 macrophages was ameliorated by treatment with the ER chaperone tauroursodeoxycholic acid. Taken together, these results showed that apoE4 expression causes macrophage dysfunction and promotes apoptosis via ER stress induction. The reduction of ER stress in macrophages may be a viable option to reduce inflammation and inflammation-related metabolic disorders associated with the apoE4 polymorphism.

Topics: Adipose Tissue; Alzheimer Disease; Animals; Apolipoprotein E3; Apolipoprotein E4; Apoptosis; Cells, Cultured; Cholagogues and Choleretics; Endoplasmic Reticulum Stress; Gene Expression Regulation; Hyperinsulinism; Inflammation; Lipopolysaccharides; Lipoproteins, LDL; Macrophages, Peritoneal; MAP Kinase Kinase 4; Metabolic Diseases; Mice; Mice, Transgenic; Phosphorylation; Polymorphism, Genetic; Signal Transduction; Taurochenodeoxycholic Acid

Obesity involves inflammation. MCP-1, an inflammatory chemokine, and MCP-1-induced protein (MCPIP) are known to induce adipogenesis that causes increase in the number of adipocytes. Here we elucidate the intermediate processes through which MCPIP induces adipogenesis. Forced expression of MCPIP in 3T3-L1 preadipocytes caused increased reactive oxygen/nitrogen species (ROS/RNS) production and inducible-nitric oxide synthase (iNOS) expression, endoplasmic reticulum stress (ER), as indicated by expression of ER chaperones and protein disulfide isomerase, and autophagy as indicated by expression of beclin-1 and cleavage of LC3. Treatment of ROS inhibitor, apocynin attenuated MCPIP induction of adipogenesis as measured by the induction of transcription factors involved in adipogenesis, adipocyte markers and lipid droplet accumulation. Inhibition of ER stress with taurursodeoxycholate or knockdown of inositol requiring enzyme 1 (IRE1) inhibited MCPIP induced autophagy and adipogenesis. Preadipocytes in adipogenesis-inducing cocktail manifested ER stress and autophagy. Knockdown of MCPIP attenuated these effects. MCPIP induced p38 activation and p38 inhibitor, SB203580, attenuated MCPIP-induced adipogenesis.

Topics: 3T3-L1 Cells; Acetophenones; Adipogenesis; Animals; Apoptosis Regulatory Proteins; Autophagy; Beclin-1; Endoplasmic Reticulum Chaperone BiP; Endoplasmic Reticulum Stress; Endoribonucleases; Heat-Shock Proteins; Imidazoles; Mice; Nitric Oxide Synthase Type II; Obesity; Oxidative Stress; p38 Mitogen-Activated Protein Kinases; Protein Serine-Threonine Kinases; Pyridines; Reactive Nitrogen Species; Reactive Oxygen Species; Ribonucleases; RNA Interference; RNA, Small Interfering; Taurochenodeoxycholic Acid

Mitochondrial dysfunction and oxidative stress are implicated in the neurodegenerative process in Parkinson's disease (PD). Moreover, c-Jun N-terminal kinase (JNK) plays an important role in dopaminergic neuronal death in substantia nigra pars compacta. Tauroursodeoxycholic acid (TUDCA) acts as a mitochondrial stabilizer and anti-apoptotic agent in several models of neurodegenerative diseases. Here, we investigated the role of TUDCA in preventing 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced neurodegeneration in a mouse model of PD. We evaluated whether TUDCA modulates MPTP-induced degeneration of dopaminergic neurons in the nigrostriatal axis, and if that can be explained by regulation of JNK phosphorylation, reactive oxygen species (ROS) production, glutathione S-transferase (GST) catalytic activation, and Akt signaling, using C57BL/6 glutathione S-transferase pi (GSTP) null mice. TUDCA efficiently protected against MPTP-induced dopaminergic degeneration. We have previously demonstrated that exacerbated JNK activation in GSTP null mice resulted in increased susceptibility to MPTP neurotoxicity. Interestingly, pre-treatment with TUDCA prevented MPTP-induced JNK phosphorylation in mouse midbrain and striatum. Moreover, the anti-oxidative role of TUDCA was demonstrated in vivo by impairment of ROS production in the presence of MPTP. Finally, results herein suggest that the survival pathway activated by TUDCA involves Akt signaling, including downstream Bad phosphorylation and NF-κB activation. We conclude that TUDCA is neuroprotective in an in vivo model of PD, acting mainly by modulation of JNK activity and cellular redox thresholds, together with activation of the Akt pro-survival pathway. These results open new perspectives for the pharmacological use of TUDCA, as a modulator of neurodegeneration in PD.

Topics: 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine; Animals; bcl-Associated Death Protein; Cell Death; Disease Models, Animal; Dopaminergic Neurons; HSP27 Heat-Shock Proteins; I-kappa B Proteins; Intracellular Space; JNK Mitogen-Activated Protein Kinases; Mice; Mice, Inbred C57BL; Mice, Knockout; Nerve Degeneration; Neuroprotective Agents; NF-kappa B; NF-KappaB Inhibitor alpha; Parkinson Disease; Phosphorylation; Reactive Oxygen Species; Taurochenodeoxycholic Acid

The sodium taurocholate cotransporting polypeptide (Ntcp) is the major bile salt uptake transporter at the sinusoidal membrane of hepatocytes. Short-term feedback regulation of Ntcp by primary bile salts has not yet been investigated in vivo. Subcellular localization of Ntcp was analyzed in Ntcp-transfected HepG2-cells by flow cytometry and in immunofluorescence images from tissue sections by a new automated image analysis method. Net bile salt uptake was investigated in perfused rat liver by a pulse chase technique. In Flag-Ntcp-EGFP (enhanced green fluorescent protein) expressing HepG2-cells, taurochenodeoxycholate (TCDC), but not taurocholate (TC), induced endocytosis of Ntcp. TCDC, but not TC, caused significant internalization of Ntcp in perfused rat livers, as shown by an increase in intracellular Ntcp immunoreactivity, whereas Bsep distribution remained unchanged. These results correlate with functional studies. Rat livers were continuously perfused with 100 μmol/L of TC. 25 μmol/L of TCDC, taurodeoxycholate (TDC), tauroursodeoxycholate (TUDC), or TC were added for 30 minutes, washed out, followed by a pulse of (3) [H]-TC. TCDC, but not TDC, TUDC, or TC significantly increased the amount of (3) [H]-TC in the effluent, indicating a reduced sinusoidal net TC uptake. This effect was sensitive to chelerythrine (protein kinase C inhibitor) and cypermethrin (protein phosphatase 2B inhibitor). Phosphoinositide 3-kinase (PI3K) inhibitors had an additive effect, whereas Erk1/2 (extracellular signal activated kinase 1/2), p38MAPK, protein phosphatase 1/2A (PP1/2A), and reactive oxygen species (ROS) were not involved.. TCDC regulates bile salt transport at the sinusoidal membrane by protein kinase C- and protein phosphatase 2B-mediated retrieval of Ntcp from the plasma membrane. During increased portal bile salt load this mechanism may adjust bile salt uptake along the acinus and protect periportal hepatocytes from harmful bile salt concentrations.

Topics: Animals; ATP Binding Cassette Transporter, Subfamily B, Member 11; ATP-Binding Cassette Transporters; Benzophenanthridines; Bile Acids and Salts; Calcineurin Inhibitors; Cholagogues and Choleretics; Down-Regulation; Endocytosis; Feedback, Physiological; Hep G2 Cells; Humans; Liver; Organic Anion Transporters, Sodium-Dependent; Phosphatidylinositol 3-Kinases; Phosphoinositide-3 Kinase Inhibitors; Protein Kinase C; Pyrethrins; Rats; Symporters; Taurochenodeoxycholic Acid; Taurocholic Acid; Taurodeoxycholic Acid

X-box binding protein-1 (XBP-1) is an important regulator of a subset of genes during endoplasmic reticulum (ER) stress. In the current study, we analyzed endogenous XBP-1 expression and localization, with a view to determining the effects of ER stress on the developmental competency of preimplantation embryos in mice. Fluorescence staining revealed that functional XBP-1 is localized on mature oocyte spindles and abundant in the nucleus at the germinal vesicle (GV) stage. However, in preimplantation embryos, XBP-1 was solely detected in the cytoplasm at the one-cell stage. The density of XBP-1 was higher in the nucleus than the cytoplasm at the two-cell, four-cell, eight-cell, morula, and blastocyst stages. Furthermore, RT-PCR analysis confirmed active XBP-1 mRNA splicing at all preimplantation embryo stages, except the one-cell stage. Tunicamycin (TM), an ER stress inducer used as a positive control, promoted an increase in the density of nuclear XBP-1 at the one-cell and two-cell stages. Similarly, culture medium supplemented with 25 mM sorbitol displayed a remarkable increase active XBP-1 expression in the nuclei of 1-cell and 2-cell embryos. Conversely, high concentrations of TM or sorbitol led to reduced nuclear XBP-1 density and significant ER stress-induced apoptosis. Tauroursodeoxycholic acid (TUDCA), a known inhibitor of ER stress, improved the rate of two-cell embryo development to blastocysts by attenuating the expression of active XBP-1 protein in the nucleus at the two-cell stage. Our data collectively suggest that endogenous XBP-1 plays a role in normal preimplantation embryonic development. Moreover, XBP-1 splicing is activated to generate a functional form in mouse preimplantation embryos during culture stress. TUDCA inhibits hyperosmolar-induced ER stress as well as ER stress-induced apoptosis during mouse preimplantation embryo development.

Topics: Animals; Apoptosis; Blastocyst; Cell Nucleus; DNA-Binding Proteins; Embryonic Development; Endoplasmic Reticulum Stress; Mice; Oocytes; Protein Transport; Regulatory Factor X Transcription Factors; RNA Splicing; RNA, Messenger; Taurochenodeoxycholic Acid; Transcription Factors; X-Box Binding Protein 1

Major diseases such as cardiovascular diseases, rheumatoid arthritis, diabetes, obesity and tumor growth are known to involve inflammation. Inflammatory molecules such as MCP-1, TNF-α, IL-1β and IL-8 are known to promote angiogenesis. MCP-induced protein (MCPIP), originally discovered as a novel zinc finger protein induced by MCP-1, is also induced by other inflammatory agents. MCPIP was shown to mediate MCP-1-induced angiogenesis. Whether angiogenesis induced by other inflammatory agents is mediated via MCPIP is unknown and the molecular mechanisms involved in angiogenesis induced by MCPIP have not been elucidated. The aim of this study was to bridge this gap and delineate the sequential processes involved in angiogenesis mediated via MCPIP. siRNA knockdown of MCPIP was used to determine whether different inflammatory agents, MCP-1, TNF-α, IL-1β and IL-8, mediate angiogenesis via MCPIP in human umbilical vein endothelial cells (HUVECs). Chemical inhibitors and specific gene knockdown approach were used to inhibit each process postulated. Oxidative stress was inhibited by apocynin or cerium oxide nanoparticles or knockdown of NADPH oxidase subunit, phox47. Endoplasmic reticulum (ER) stress was blocked by tauroursodeoxycholate or knockdown of ER stress signaling protein IRE-1 and autophagy was inhibited by the use of 3'methyl adenine, or LY 294002 or by specific knockdown of beclin1. Matrigel assay was used as a tool to study angiogenic differentiation induced by inflammatory agents or MCPIP overexpression in HUVECs. Tube formation induced by inflammatory agents, TNF-α, IL-1β, IL-8 and MCP-1 was inhibited by knockdown of MCPIP. Forced MCPIP-expression induced oxidative stress, ER stress, autophagy and angiogenic differentiation in HUVECs. Inhibition of each step caused inhibition of each subsequent step postulated. The results reveal that angiogenesis induced by inflammatory agents is mediated via induction of MCPIP that causes oxidative and nitrosative stress resulting in ER stress leading to autophagy required for angiogenesis. The sequence of events suggested to be involved in inflammatory angiogenesis by MCPIP could serve as possible targets for therapeutic intervention of angiogenesis-related disorders.

Topics: Acetophenones; Anti-Inflammatory Agents, Non-Steroidal; Antiviral Agents; Apoptosis Regulatory Proteins; Autophagy; Beclin-1; Chemokine CCL2; Chromones; Endoplasmic Reticulum Stress; Endoribonucleases; Human Umbilical Vein Endothelial Cells; Humans; Interleukin-1beta; Interleukin-8; Membrane Proteins; Morpholines; Neovascularization, Physiologic; Oxidative Stress; Protein Serine-Threonine Kinases; Reactive Oxygen Species; Ribonucleases; RNA Interference; RNA, Small Interfering; Taurochenodeoxycholic Acid; Transcription Factors; Tumor Necrosis Factor-alpha

Hazardous levels of bilirubin produce oxidative stress in vitro and may play a role in the genesis of bilirubin-induced neurologic dysfunction (BIND). We hypothesized that the antioxidants taurourosdeoxycholic acid (TUDCA), 12S-hydroxy-1,12-pyrazolinominocycline (PMIN), and minocycline (MNC) inhibit oxidative stress and block BIND in hyperbilirubinemic j/j Gunn rat pups that were given sulfadimethoxine to induce bilirubin encephalopathy.. At peak postnatal hyperbilirubinemia, j/j Gunn rat pups were dosed with sulfadimethoxine to induce bilirubin encephalopathy. Pups were given TUDCA, PMIN, MNC, or vehicle pretreatment (15 min before sulfadimethoxine). After 24 h, BIND was scored by using a rating scale of neurobehavior and cerebellar tissue 4-hydroxynonenal and protein carbonyl dinitrophenyl content were determined. Nonjaundiced heterozygous N/j pups served as controls.. Administration of sulfadimethoxine induced BIND and lipid peroxidation but not protein oxidation in hyperbilirubinemic j/j pups. TUDCA, PMIN, and MNC each reduced lipid peroxidation to basal levels observed in nonjaundiced N/j controls, but only MNC prevented BIND.. These findings show that lipid peroxidation inhibition alone is not sufficient to prevent BIND. We speculate that the neuroprotective efficacy of MNC against BIND involves action(s) independent of, or in addition to, its antioxidant effects.

Topics: Aldehydes; Animals; Animals, Newborn; Antioxidants; Behavior, Animal; Bilirubin; Cerebellum; Disease Models, Animal; Humans; Infant, Newborn; Jaundice, Neonatal; Kernicterus; Lipid Peroxidation; Minocycline; Motor Activity; Neuroprotective Agents; Oxidative Stress; Protein Carbonylation; Pyrazoles; Rats; Rats, Gunn; Sulfadimethoxine; Taurochenodeoxycholic Acid; Time Factors

Numerous steatotic livers are discarded for transplantation because of their poor tolerance to ischemia-reperfusion (I/R). We examined whether tauroursodeoxycholic acid (TUDCA), a known inhibitor of endoplasmic reticulum (ER) stress, protects steatotic and nonsteatotic liver grafts preserved during 6 h in University of Wisconsin (UW) solution and transplanted. The protective mechanisms of TUDCA were also examined. Neither unfolded protein response (UPR) induction nor ER stress was evidenced in steatotic and nonsteatotic liver grafts after 6 h in UW preservation solution. TUDCA only protected steatotic livers grafts and did so through a mechanism independent of ER stress. It reduced proliferator-activated receptor-γ (PPARγ) and damage. When PPARγ was activated, TUDCA did not reduce damage. TUDCA, which inhibited PPARγ, and the PPARγ antagonist treatment up-regulated toll-like receptor 4 (TLR4), specifically the TIR domain-containing adaptor inducing IFNβ (TRIF) pathway. TLR4 agonist treatment reduced damage in steatotic liver grafts. When TLR4 action was inhibited, PPARγ antagonists did not protect steatotic liver grafts. In conclusion, TUDCA reduced PPARγ and this in turn up-regulated the TLR4 pathway, thus protecting steatotic liver grafts. TLR4 activating-based strategies could reduce the inherent risk of steatotic liver failure after transplantation.

Topics: Animals; Antiviral Agents; Blotting, Western; Endoplasmic Reticulum; Fatty Liver; Liver Transplantation; Male; Obesity; Organ Preservation; PPAR gamma; Rats; Rats, Sprague-Dawley; Rats, Wistar; Rats, Zucker; Reperfusion Injury; Taurochenodeoxycholic Acid; Toll-Like Receptor 4; Transplantation, Isogeneic; Unfolded Protein Response

Although endoplasmic reticulum (ER) stress is a pathologic mechanism in a variety of chronic diseases, it is unclear what role it plays in chronic hypertension (HTN). Dysregulation of brain mechanisms controlling arterial pressure is strongly implicated in HTN, particularly in models involving angiotensin II (Ang II). We tested the hypothesis that ER stress in the brain is causally linked to Ang II-dependent HTN. Chronic systemic infusion of low-dose Ang II in C57BL/6 mice induced slowly developing HTN, which was abolished by co-infusion of the ER stress inhibitor tauroursodeoxycholic acid (TUDCA) into the lateral cerebroventricle. Investigations of the brain regions involved revealed robust increases in ER stress biomarkers and profound ER morphological abnormalities in the circumventricular subfornical organ (SFO), a region outside the blood-brain barrier and replete with Ang II receptors. Ang II-induced HTN could be prevented in this model by selective genetic supplementation of the ER chaperone 78-kDa glucose-regulated protein (GRP78) in the SFO. These data demonstrate that Ang II-dependent HTN is mediated by ER stress in the brain, particularly the SFO. To our knowledge, this is the first report that ER stress, notably brain ER stress, plays a key role in chronic HTN. Taken together, these findings may have broad implications for the pathophysiology of this disease.

Topics: Angiotensin II; Animals; Brain; Cholagogues and Choleretics; Chronic Disease; Endoplasmic Reticulum Chaperone BiP; Endoplasmic Reticulum Stress; Heat-Shock Proteins; Hypertension; Mice; Subfornical Organ; Taurochenodeoxycholic Acid; Vasoconstrictor Agents

Adipose tissue plays a central role in maintaining metabolic homeostasis under normal conditions. Metabolic diseases such as obesity and type 2 diabetes are often accompanied by chronic inflammation and adipose tissue dysfunction. In this study, we observed that endoplasmic reticulum (ER) stress and the inflammatory response occurred in adipose tissue of mice fed a high-fat diet for a period of 16 weeks. After 16 weeks of feeding, ER stress markers increased and chronic inflammation occurred in adipose tissue. We found that ER stress is induced by free fatty acid (FFA)-mediated reactive oxygen species (ROS) generation and up-regulated gene expression of inflammatory cytokines in 3T3-L1 adipocytes. Oral administration to obese mice of chemical chaperons, which alleviate ER stress, improved chronic inflammation in adipose tissue, followed by the suppression of increased body weight and improved insulin signaling. These results indicate that ER stress plays important pathophysiological roles in obesity-induced adipose tissue dysfunction.

Topics: 3T3-L1 Cells; Adipose Tissue; Administration, Oral; Animals; Body Weight; Butylamines; Chronic Disease; Cytokines; Diet, High-Fat; Endoplasmic Reticulum Stress; Fatty Acids, Nonesterified; Inflammation; Insulin; Male; Mice; Mice, Inbred C57BL; Obesity; Reactive Oxygen Species; Signal Transduction; Taurochenodeoxycholic Acid; Up-Regulation

Acute kidney injury (AKI) has grave short- and long-term consequences. Often the onset of AKI is predictable, such as following surgery that compromises blood flow to the kidney. Even in such situations, present therapies cannot prevent AKI. As apoptosis is a major form of cell death following AKI, we determined the efficacy and mechanisms of action of tauroursodeoxycholic acid (TUDCA), a molecule with potent anti-apoptotic and pro-survival properties, in prevention of AKI in rat and cell culture models. TUDCA is particularly attractive from a translational standpoint, as it has a proven safety record in animals and humans.. We chose an ischemia-reperfusion model in rats to simulate AKI in native kidneys, and a human kidney cell culture model to simulate AKI associated with cryopreservation in transplanted kidneys. TUDCA significantly ameliorated AKI in the test models due to inhibition of the mitochondrial pathway of apoptosis and upregulation of survival pathways.. This study sets the stage for testing TUDCA in future clinical trials for prevention of AKI, an area that needs urgent attention due to lack of effective therapies.

Topics: Acute Kidney Injury; Animals; Apoptosis; Caspases; Cell Culture Techniques; Cell Survival; Disease Models, Animal; Enzyme Activation; Epithelial Cells; Humans; Kidney Tubules, Proximal; Male; Protective Agents; Rats; Signal Transduction; Taurochenodeoxycholic Acid

Free-fatty acids (FFAs) are well-characterized factor for causing production of inflammatory factors and insulin resistance in adipocytes. Using cultured adipocytes, we demonstrate that FFAs can activate endoplasmic reticulum (ER) stress pathway by examination of ER stress sensor activation and marker gene expression. Chemical chaperone tauroursodeoxycholic acid (TUDCA) can reduce FFA-induced adipocyte inflammation and improve insulin signaling whereas overexpression of spliced X-box protein 1 (XBP-1s) only attenuates FFA-induced inflammation. PKR-like eukaryotic initiation factor 2α kinase (PERK) is one of the three major ER stress sensor proteins and deficiency of PERK alleviates FFA-induced inflammation and insulin resistance. The key downstream target of FFA-induced ER stress is IκB kinase β (IKKβ), a master kinase for regulating expression of inflammatory genes. Deficiency of PERK attenuates FFA-induced activation of IKKβ and deficiency of IKKβ alleviates FFA-induced inflammation and insulin resistance. Consistently, overexpression of IKKβ in 3T3-L1 CAR adipocytes causes inflammation and insulin resistance. In addition, IKKβ overexpression has profound effect on adipocyte lipid metabolism, including inhibition of lipogenesis and promotion of lipolysis. Furthermore, increased endogenous IKKβ expression and activation is also observed in isolated primary adipocytes from mice injected with lipids or fed on high-fat diet (HFD) acutely. These results indicate that ER stress pathway is a key mediator for FFA-induced inflammation and insulin resistance in adipocytes with PERK and IKKβ as the critical signaling components.

Topics: 3T3-L1 Cells; Adipocytes; Animals; Dietary Fats; DNA-Binding Proteins; eIF-2 Kinase; Endoplasmic Reticulum; Fatty Acids, Nonesterified; I-kappa B Kinase; Inflammation; Insulin; Insulin Resistance; Lipid Metabolism; Male; Mice; Mice, Inbred C57BL; Regulatory Factor X Transcription Factors; Signal Transduction; Taurochenodeoxycholic Acid; Transcription Factors; X-Box Binding Protein 1

ER stress is involved in the pathophysiology of obesity although little is known about the role of ER stress on obesity-associated cardiac dysfunction. This study was designed to examine the effect of ER chaperone tauroursodeoxycholic acid (TUDCA) on obesity-induced myocardial dysfunction. Adult lean and ob/ob obese mice were treated with TUDCA (50mg/kg/day, p.o.) or vehicle for 5 weeks. Oral glucose tolerance test (OGTT) was performed. Echocardiography, cardiomyocyte contractile and intracellular Ca(2+) properties were assessed. Sarco(endo)plasmic reticulum Ca(2+)-ATPase (SERCA) activity and protein expression of intracellular Ca(2+) regulatory proteins were measured using (45)Ca(2+) uptake and Western blot analysis, respectively. Insulin signaling, ER stress markers and HSP90 were evaluated. Our results revealed that chronic TUDCA treatment lowered systolic blood pressure and lessened glucose intolerance in obese mice. Obesity led to increased diastolic diameter, cardiac hypertrophy, compromised fractional shortening, cardiomyocyte contractile (peak shortening, maximal velocity of shortening/relengthening, and duration of contraction/relaxation) and intracellular Ca(2+) properties, all of which were significantly attenuated by TUDCA. TUDCA reconciled obesity-associated decrease in SERCA activity and expression, and increase in serine phosphorylation of IRS, total and phosphorylated cJun, ER stress markers Bip, peIF2α and pPERK. Obesity-induced changes in phospholamban and HSP90 were unaffected by TUDCA. In vitro finding revealed that TUDCA ablated palmitic acid-induced cardiomyocyte contractile dysfunction. In summary, these data depicted a pivotal role of ER stress in obesity-associated cardiac contractile dysfunction, suggesting the therapeutic potential of ER stress as a target in the management of cardiac dysfunction in obesity.

Topics: Animals; Blood Pressure; Blotting, Western; Calcium; Cells, Cultured; Echocardiography; Endoplasmic Reticulum; Glucose Tolerance Test; Male; Mice; Mice, Inbred C57BL; Mice, Obese; Myocardial Contraction; Myocytes, Cardiac; Obesity; Sarcoplasmic Reticulum Calcium-Transporting ATPases; Taurochenodeoxycholic Acid

Two constituents of bile, bilirubin and tauroursodeoxycholic acid (TUDCA), have antioxidant activity. However, bilirubin can also cause damage to some neurons and glial cells, particularly immature neurons. In this study, we tested the effects of bilirubin and TUDCA in two models in which oxidative stress contributes to photoreceptor cell death, prolonged light exposure and rd10+/+ mice. In albino BALB/c mice, intraperitoneal injection of 5 mg/kg of bilirubin or 500 mg/kg of TUDCA prior to exposure to 5000 lux of white light for 8 h significantly reduced loss of rod and cone function assessed by electroretinograms. Both treatments also reduced light-induced accumulation of superoxide radicals in the outer retina, rod cell death assessed by outer nuclear layer thickness, and disruption of cone inner and outer segments. In rd10+/+ mice, intraperitoneal injections of 5 or 50 mg/kg of bilirubin or 500 mg/kg of TUDCA every 3 days starting at postnatal day (P) 6, caused significant preservation of cone cell number and cone function at P50. Rods were not protected at P50, but both bilirubin and TUDCA provided modest preservation of outer nuclear layer thickness and rod function at P30. These data suggest that correlation of serum bilirubin levels with rate of vision loss in patients with retinitis pigmentosa could provide a useful strategy to test the hypothesis that cones die from oxidative damage in patients with retinitis pigmentosa. If proof-of-concept is established, manipulation of bilirubin levels and administration of TUDCA could be tested in interventional trials.

Topics: Animals; Bile; Bilirubin; Female; Humans; Mice; Mice, Inbred BALB C; Neuroprotective Agents; Oxidative Stress; Retinal Degeneration; Taurochenodeoxycholic Acid

Exposure of cell lines endogenously expressing the thyroid hormone activating enzyme type 2 deiodinase (D2) to the chemical chaperones tauroursodeoxycholic acid (TUDCA) or 4-phenylbutiric acid (4-PBA) increases D2 expression, activity and T3 production. In brown adipocytes, TUDCA or 4-PBA induced T3-dependent genes and oxygen consumption (∼2-fold), an effect partially lost in D2 knockout cells. In wild type, but not in D2 knockout mice, administration of TUDCA lowered the respiratory quotient, doubled brown adipose tissue D2 activity and normalized the glucose intolerance associated with high fat feeding. Thus, D2 plays a critical role in the metabolic effects of chemical chaperones.

Topics: Adipocytes, Brown; Animals; Cell Line; Cells, Cultured; Dietary Fats; Energy Metabolism; Gene Expression Regulation; Gene Knockout Techniques; Glucose Intolerance; Humans; Iodide Peroxidase; Iodothyronine Deiodinase Type II; Lipid Metabolism; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Oxygen Consumption; Phenylbutyrates; RNA, Messenger; Taurochenodeoxycholic Acid; Triiodothyronine

Hepatic steatosis continues to present a major challenge in liver transplantation. These organs have been shown to have increased susceptibility to cold ischemia/reperfusion (CIR) injury in comparison with otherwise comparable lean livers; the mechanisms governing this increased susceptibility to CIR injury are not fully understood. Endoplasmic reticulum (ER) stress is an important link between hepatic steatosis, insulin resistance, and metabolic syndrome. In this study, we investigated ER stress signaling and blockade in the mediation of CIR injury in severely steatotic rodent allografts. Steatotic allografts from genetically leptin-resistant rodents had increased ER stress responses and increased markers of hepatocellular injury after liver transplantation into strain-matched lean recipients. ER stress response components were reduced by the chemical chaperone taurine-conjugated ursodeoxycholic acid (TUDCA), and this resulted in an improvement in the allograft injury. TUDCA treatment decreased nuclear factor kappa B activation and the proinflammatory cytokines interleukin-6 and interleukin-1β. However, the predominant response was decreased expression of the ER stress cell death mediator [CCAAT/enhancer-binding protein homologous protein (CHOP)]. Furthermore, activation of inflammation-associated caspase-11 was decreased, and this linked ER stress/CHOP to proinflammatory cytokine production after steatotic liver transplantation. These data confirm ER stress in steatotic allografts and implicate this as a mediating mechanism of inflammation and hepatocyte death in the steatotic liver allograft.

Topics: Activating Transcription Factor 4; Animals; Caspases; Disease Models, Animal; Endoplasmic Reticulum; Fatty Liver; Heat-Shock Proteins; Inflammation Mediators; Interleukin-1beta; Interleukin-6; Liver; Liver Transplantation; NF-kappa B; Non-alcoholic Fatty Liver Disease; Rats; Rats, Zucker; Reperfusion Injury; Signal Transduction; Stress, Physiological; Taurochenodeoxycholic Acid; Time Factors; Transcription Factor CHOP; Transplantation, Homologous

Chronic endoplasmic reticulum (ER) stress was recently revealed to affect hypothalamic neuroendocrine pathways that regulate feeding and body weight. However, it remains unexplored whether brain ER stress could use a neural route to rapidly cause the peripheral disorders that underlie the development of type 2 diabetes (T2D) and the metabolic syndrome. Using a pharmacologic model that delivered ER stress inducer thapsigargin into the brain, this study demonstrated that a short-term brain ER stress over 3 d was sufficient to induce glucose intolerance, systemic and hepatic insulin resistance, and blood pressure (BP) increase. The collection of these changes was accompanied by elevated sympathetic tone and prevented by sympathetic suppression. Molecular studies revealed that acute induction of metabolic disorders via brain ER stress was abrogated by NF-κB inhibition in the hypothalamus. Therapeutic experiments further revealed that acute inhibition of brain ER stress with tauroursodeoxycholic acid (TUDCA) partially reversed obesity-associated metabolic and blood pressure disorders. In conclusion, ER stress in the brain represents a mediator of the sympathetic disorders that underlie the development of insulin resistance syndrome and T2D.

Topics: Animals; Blood Pressure; Blotting, Western; Body Weight; Diabetes Mellitus, Type 2; Eating; Endoplasmic Reticulum; Enzyme-Linked Immunosorbent Assay; Glucose Intolerance; Green Fluorescent Proteins; Hypothalamus; Immunoprecipitation; Insulin; Insulin Resistance; Male; Mice; Mice, Inbred C57BL; Neurosecretory Systems; NF-kappa B; Reverse Transcriptase Polymerase Chain Reaction; Stress, Physiological; Taurochenodeoxycholic Acid; Telemetry; Thapsigargin

Human lens membranes contain the highest cholesterol concentration of any known biological membranes, but it significantly decreases with age. Oxygenation of cholesterol generates numerous forms of oxysterols (bile acids). We previously showed that two forms of the bile acid components--ursodeoxycholic acid (UDCA) and tauroursodeoxycholic acid (TUDCA)--suppressed lens epithelial cell death and alleviated cataract formation in galactosemic rat lenses. We investigated whether these compounds also suppress the thermal aggregation of human lens crystallins. Total water-soluble (WS) proteins were prepared from human lenses, and recombinant human crystallins (αA-, αB-, βB2-, and γC-crystallin) were generated by a prokaryotic expression system and purified by liquid chromatography. The light scattering of proteins in the presence or absence of UDCA or TUDCA was measured using a spectrofluorometer set at Ex/Em = 400/400 nm. Protein blot analysis was conducted for detection of α-crystallins in the human lens WS proteins. High concentrations of UDCA and TUDCA significantly suppressed thermal aggregation of total lens WS proteins, which contained a low level of αA-/αB-crystallin. Spectroscopic analysis with each recombinant human lens crystallin indicated that the bile acids did not suppress the thermal aggregation of γC-, βB2-, αA-, or αB-crystallin. Combination of α-crystallin and bile acid (either UDCA or TUDCA) suppressed thermal aggregation of each individual crystallin as well as a non-crystallin protein, insulin. These results suggest that UDCA or TUDCA protects the chaperone activity of α-crystallin. It is believed that these two naturally occurring intermediate waste products in the lens enhance the chaperone activity of α-crystallin. This finding may lead to the development of UDCA and TUDCA as anticataract agents.

Topics: alpha-Crystallins; Animals; Bile Acids and Salts; Cholagogues and Choleretics; Cholesterol; Humans; Lens, Crystalline; Middle Aged; Molecular Chaperones; Molecular Structure; Protein Isoforms; Rats; Recombinant Proteins; Taurochenodeoxycholic Acid; Ursodeoxycholic Acid

Metabolic profile of bile acids was used to evaluate hepatotoxicity of mice caused by ethanol extraction of Dioscorea bulbifera L. (ethanol extraction, ET) and diosbulbin B (DB), separately. Ultra-performance liquid chromatography coupled with quadrupole mass spectrometry (UPLC-MS) was applied to determine the contents of all kinds of endogenous bile acids including free bile acids, taurine conjugates and glycine conjugates. Obvious liver injuries could be observed in mice after administrated with ET and DB. Based on the analysis using principle components analysis (PCA), toxic groups could be distinguished from their control groups, which suggested that the variance of the contents of bile acids could evaluate hepatotoxicity caused by ET and DB. Meanwhile, ET and DB toxic groups were classified in the same trends comparing to control groups in the loading plot, and difference between the two toxic groups could also be observed. DB proved to be one of the toxic components in Dioscorea bulbifera L. Bile acids of tauroursodeoxycholic acid (TUDCA), taurochenodeoxycholic acid (TCDCA), taurocholic acid (TCA), taurodeoxycholic acid (TDCA), cholic acid (CA) and others proved to be important corresponds to ET and DB induced liver injury according to analysis of partial least square-discriminant analysis (PLS-DA) and the statistical analysis showed that there were significant differences between the control groups and toxic groups (P < 0.01). Furthermore, good correlation could be revealed between the foregoing bile acids and ALT, AST. It indicated that taurine conjugated bile acids as TUDCA, TCDCA, TCA and TDCA along with CA could be considered as sensitive biomarkers of ET and DB induced liver injury. This work can provide the base for the further research on the evaluation and mechanism of hepatotoxicity caused by Dioscorea bulbifera L.

Topics: Animals; Bile Acids and Salts; Chemical and Drug Induced Liver Injury; Cholic Acid; Chromatography, High Pressure Liquid; Dioscorea; Drugs, Chinese Herbal; Heterocyclic Compounds, 4 or More Rings; Least-Squares Analysis; Male; Mice; Mice, Inbred ICR; Plants, Medicinal; Principal Component Analysis; Rhizome; Tandem Mass Spectrometry; Taurochenodeoxycholic Acid; Taurocholic Acid; Taurodeoxycholic Acid

To evaluate the preventive effect of tauroursodeoxycholic acid (TUDCA) on photoreceptor degeneration, synaptic connectivity and functional activity of the retina in the transgenic P23H rat, an animal model of autosomal dominant retinitis pigmentosa (RP).. P23H line-3 rats were injected with TUDCA once a week from postnatal day (P)21 to P120, in parallel with vehicle-administered controls. At P120, functional activity of the retina was evaluated by electroretinographic (ERG) recording. The effects of TUDCA on the number, morphology, integrity, and synaptic connectivity of retinal cells were characterized by immunofluorescence confocal microscopy.. The amplitude of ERG a- and b-waves was significantly higher in TUDCA-treated animals under both scotopic and photopic conditions than in control animals. In the central area of the retina, TUDCA-treated P23H rats showed threefold more photoreceptors than control animals. The number of TUNEL-positive cells was significantly smaller in TUDCA-treated rats, in which photoreceptor morphology was preserved. Presynaptic and postsynaptic elements, as well as the synaptic contacts between photoreceptors and bipolar or horizontal cells, were preserved in TUDCA-treated P23H rats. Furthermore, in TUDCA-treated rat retinas, the number of both rod bipolar and horizontal cell bodies, as well as the density of their synaptic terminals in the outer plexiform layer, was greater than in control rats.. TUDCA treatment was capable of preserving cone and rod structure and function, together with their contacts with their postsynaptic neurons. The neuroprotective effects of TUDCA make this compound potentially useful for delaying retinal degeneration in RP.

Topics: Animals; Cholagogues and Choleretics; Color Vision; Disease Models, Animal; Electroretinography; In Situ Nick-End Labeling; Injections, Intraperitoneal; Microscopy, Confocal; Night Vision; Photoreceptor Cells, Vertebrate; Presynaptic Terminals; Rats; Rats, Transgenic; Retinal Bipolar Cells; Retinal Degeneration; Taurochenodeoxycholic Acid

Due to the importance of intestinal transport in pharmacological studies and the emerging role of intestinal signaling activity in the gut-liver axis, we have developed a new method to investigate intestinal transport and liver signaling using cell and serum free mesenteric perfusion system in the rat. The method regarding bile acid active absorption was validated, then, the portal venous content was examined for fibroblast growth factor 15(FGF15), a putative signaling protein produced by the ileal enterocytes following bile acid absorption. After isolation and cannulation of the relevant vessels (abdominal aorta and portal vein), the abdominal aorta and the terminal ileum were infused with respectively Krebs-Ringer solution and tauroursodeoxycholate (TUDCA) and the absorption was assessed by its recovery in the portal vein. After immunoblot, liquid chromatography and mass spectrometry analysis were performed both on gel bands digestion products and on portal outflow samples in order to evaluate if negligible amounts of FGF15 were present in the portal circulation. TUDCA absorption was efficient, intestinal morphology and oxygen consumption were normal. Despite accurate analysis, we could not find FGF15. Our method proved to be reliable for studying the active bile acid absorption. It is also suitable to identify molecules produced by enterocytes and transferred to the portal circulation in response to absorption of different substances such as nutrients or drugs. Since FGF15 was not recovered we suggest the possibilities that this protein is produced in very little amounts, poorly transferred outside the cell, or that it is extremely unstable and rapidly degraded.

Topics: Animals; Bile; Cell Respiration; Cholagogues and Choleretics; Enterocytes; Fibroblast Growth Factors; Ileum; Intestinal Absorption; Intestinal Mucosa; Intestines; Isotonic Solutions; Liver; Male; Models, Animal; Portal Vein; Rats; Rats, Sprague-Dawley; Taurochenodeoxycholic Acid

Inflammatory bowel diseases (IBD) are chronically relapsing and immune-mediated disorders of the gastrointestinal tract. Endoplasmic reticulum (ER) stress mechanisms in the epithelium have been demonstrated to be implemented into the pathogenesis of intestinal inflammation. Chemical chaperones have been demonstrated to exhibit beneficial effects in various diseases associated with ER stress mechanisms by prohibiting the unfolded protein response (UPR). In a structure-function analysis, we tested the potential of the conjugated bile salt sodium tauroursodeoxycholate (TUDCA), naturally present in the small bowel, to resolve ER stress in intestinal epithelial cells. TUDCA efficiently inhibited the expression of UPR dependent genes like GRP78 triggered by the ER stressor tunicamycin in the small intestinal epithelial cell line Mode-K. TUDCA inhibited upstream signaling events in all three branches of the UPR cascade and diminished binding of UPR activated transcription factors to the grp78 promoter. A structure-function analysis revealed that UDCA but not its conjugation partner taurine, known as a chemical chaperone, is responsible for the inhibition of GRP78 induction and that UDCA is 10 times more effective than its taurine conjugate. This inhibitory effect was confirmed in a cell free assay, where TUDCA and UDCA but not taurine effectively inhibited the aggregation of thermally denatured BSA. We conclude that TUDCA and UDCA are potent anti-aggregants for the resolution of ER stress in intestinal epithelial cells and should be considered as a potential drug target to resolve ER stress mechanisms underlying the pathology of IBD.

Topics: Animals; Cell Line; Endoplasmic Reticulum; Endoplasmic Reticulum Chaperone BiP; Intestinal Mucosa; Mice; Stress, Physiological; Structure-Activity Relationship; Taurochenodeoxycholic Acid; Unfolded Protein Response

Multidrug resistance-associated protein 2 (MRP2; ABCC2) mediates the biliary excretion of glutathione, glucuronide, and sulfate conjugates of endobiotics and xenobiotics. Single nucleotide polymorphisms (SNPs) of MRP2 contribute to interindividual variability in drug disposition and ultimately in drug response.. To characterize the transport function of human wild-type (WT) MRP2 and four SNP variants, S789F, A1450T, V417I, and T1477M.. The four SNP variants were expressed in Sf9 cells using recombinant baculovirus infection. The kinetic parameters [Km, (μmol/l); V(max), (pmol/mg/min); the Hill coefficient] of ATP-dependent transport of leukotriene C(4) (LTC(4)), estradiol-3-glucuronide (E(2)3G), estradiol-17β-glucuronide (E(2)17G), and tauroursodeoxycholic acid (TUDC) were determined in Sf9-derived plasma membrane vesicles. Transport activity was normalized for expression level.. The V(max) for transport activity was decreased for all substrates for S789F, and for all substrates except E(2)17G for A1450T. V417I showed decreased apparent affinity for LTC(4), E(2)3G, and E(2)17G, whereas transport was similar between wild-type (WT) and T1477M, except for a modest increase in TUDC transport. Examination of substrate-stimulated MRP2-dependent ATPase activity of S789F and A1450T, SNPs located in MRP2 nucleotide-binding domains (NBDs), demonstrated significantly decreased ATPase activity and only modestly decreased affinity for ATP compared with WT.. SNPs in the NBDs (S789F in the D-loop of NBD1, or A1450T near the ABC signature motif of NBD2) variably decreased the transport of all substrates. V417I in membrane spanning domain 1 selectively decreased the apparent affinity for the glutathione and glucuronide conjugated substrates, whereas the T1477M SNP in the carboxyl terminus altered only TUDC transport.

Topics: Adenosine Triphosphatases; Baculoviridae; Biomarkers, Pharmacological; Drug Resistance, Multiple; Estradiol; Genetic Vectors; Glucuronides; Glutathione; Humans; Leukotriene C4; Multidrug Resistance-Associated Protein 2; Multidrug Resistance-Associated Proteins; Polymorphism, Single Nucleotide; Taurochenodeoxycholic Acid

Amyloid-β (Aβ) peptide-induced neurotoxicity is typically associated with cell death through mechanisms not entirely understood. Here, we investigated stress signaling events triggered by soluble Aβ in differentiated rat neuronal-like PC12 cells. Morphologic evaluation of apoptosis confirmed that Aβ induced nuclear fragmentation that was prevented by pre-treatment with the antiapoptotic bile acid tauroursodeoxycholic acid (TUDCA). In addition, Aβ exposure triggered an early signaling response by the endoplasmic reticulum (ER) and caspase-12-mediated apoptosis, which, however, was independent of the ER-stress pathway. Furthermore, ER stress markers, including GRP94, ATF-6α, CHOP, and eIF2α, were strongly downregulated by Aβ, independent of protein degradation, and partially restored by TUDCA. Calpain inhibition prevented caspase-12 activation and reduced levels of ATF-6α. Importantly, Aβ-induced GRP94 downregulation was related to protein secretion and partially rescued through inhibition of the secretory pathway by geldanamycin and brefeldin. In conclusion, we showed that the ER is a proximal stress sensor for soluble Aβ-induced toxicity, resulting in caspase-12 activation and cell death in PC12 neuronal cells. Moreover, ER chaperone GRP94 secretion was associated with Aβ-induced apoptotic signaling. These data provide new information linking apoptotic properties of Aβ peptide to distinct subcellular mechanisms of toxicity. Further characterization of this signaling pathway is likely to provide new perspectives for modulation of amyloid-induced apoptosis.

Topics: Activating Transcription Factor 6; Amyloid beta-Peptides; Animals; Apoptosis; Brefeldin A; Calcium; Caspase 12; Cell Survival; Cholagogues and Choleretics; DNA-Binding Proteins; Dose-Response Relationship, Drug; Endoplasmic Reticulum; Enzyme Inhibitors; Enzyme-Linked Immunosorbent Assay; Gene Expression Regulation; HSP70 Heat-Shock Proteins; Lactones; Membrane Proteins; PC12 Cells; Peptide Fragments; Rats; Sesquiterpenes; Taurochenodeoxycholic Acid; Transcription Factor CHOP

In acute pancreatitis, endoplasmic reticulum (ER) stress prompts an accumulation of malfolded proteins inside the ER, initiating the unfolded protein response (UPR). Because the ER chaperone tauroursodeoxycholic acid (TUDCA) is known to inhibit the UPR in vitro, this study examined the in vivo effects of TUDCA in an acute experimental pancreatitis model. Acute pancreatitis was induced in Wistar rats using caerulein, with or without prior TUDCA treatment. UPR components were analyzed, including chaperone binding protein (BiP), phosphorylated protein kinase-like ER kinase (pPERK), X-box binding protein (XBP)-1, phosphorylated c-Jun NH(2)-terminal kinase (pJNK), CCAAT/enhancer binding protein homologues protein, and caspase 12 and 3 activation. In addition, pancreatitis biomarkers were measured, such as serum amylase, trypsin activation, edema formation, histology, and the inflammatory reaction in pancreatic and lung tissue. TUDCA treatment reduced intracellular trypsin activation, edema formation, and cell damage, while leaving amylase levels unaltered. The activation of myeloperoxidase was clearly reduced in pancreas and lung. Furthermore, TUDCA prevented caerulein-induced BiP upregulation, reduced XBP-1 splicing, and caspase 12 and 3 activation. It accelerated the downregulation of pJNK. In controls without pancreatitis, TUDCA showed cytoprotective effects including pPERK signaling and activation of downstream targets. We concluded that ER stress responses activated in acute pancreatitis are grossly attenuated by TUDCA. The chaperone reduced the UPR and inhibited ER stress-associated proapoptotic pathways. TUDCA has a cytoprotective potential in the exocrine pancreas. These data hint at new perspectives for an employment of chemical chaperones, such as TUDCA, in prevention of acute pancreatitis.

Topics: Acinar Cells; Animals; Ceruletide; Endoplasmic Reticulum; Endoplasmic Reticulum Stress; Inflammation; Male; Pancreas; Pancreatitis; Rats; Rats, Wistar; Taurochenodeoxycholic Acid; Unfolded Protein Response

Hyperplasia of vascular smooth muscle cells (VSMCs) after blood vessel injury is one of the major pathophysiological mechanisms associated with neointima. Tauroursodeoxycholate (TUDCA) is a cytoprotective agent in a variety of cells including hepatocytes as well as an inducer of apoptosis in cancer cells. In this study, we investigated whether TUDCA could prevent neointimal hyperplasia by suppressing the growth and migration of VSMCs.. Transporters of TUDCA uptake in human VSMCs (hVSMCs) were analysed by RT-PCR and western blot. A knock-down experiment using specific si-RNA revealed that TUDCA was incorporated into hVSMCs via organic anion transporter 2 (OATP2). TUDCA reduced the viability of hVSMCs, which were mediated by inhibition of extracellular signal-regulated kinase (ERK) by induction of mitogen-activated protein kinase phosphatase-1 (MKP-1) via protein kinase Cα (PKCα). The anti-proliferative effect of TUDCA was reversed by treatment with 7-hydroxystaurosporine, an inhibitor of PKC, and by the knock-down of MKP-1. In addition, TUDCA suppressed hVSMC migration, which was mediated by reduced matrix metalloproteinase-9 (MMP-9) expression by ERK inhibition, as well as reduced viability of hVSMCs. Rats with carotid artery balloon injury received oral administration of TUDCA; this reduced the increase in ERK and MMP-9 caused by balloon injury. TUDCA significantly decreased the ratio of intima to media by reducing proliferation and inducing apoptosis of the VSMCs.. TUDCA inhibits neointimal hyperplasia by reducing proliferation and inducing apoptosis of smooth muscle cells by suppression of ERK via PKCα-mediated MKP-1 induction.

Topics: Animals; Apoptosis; Biological Transport; Carotid Artery Injuries; Cell Movement; Cell Proliferation; Cell Survival; Cells, Cultured; Cytoprotection; Disease Models, Animal; Dose-Response Relationship, Drug; Dual Specificity Phosphatase 1; Enzyme Activation; Extracellular Signal-Regulated MAP Kinases; Humans; Hyperplasia; Liver-Specific Organic Anion Transporter 1; Matrix Metalloproteinase 9; Muscle, Smooth, Vascular; Myocytes, Smooth Muscle; Phosphorylation; Protein Kinase C-alpha; Protein Kinase Inhibitors; Rats; Rats, Sprague-Dawley; RNA Interference; Staurosporine; Taurochenodeoxycholic Acid; Time Factors; Transfection; Tunica Intima; Up-Regulation

Detachment of photoreceptors from the underlying retinal pigment epithelium is seen in various retinal disorders such as retinal detachment and age-related macular degeneration and leads to loss of photoreceptors and vision. Pharmacologic inhibition of photoreceptor cell death may prevent this outcome. This study tests whether systemic administration of tauroursodeoxycholic acid (TUDCA) can protect photoreceptors from cell death after experimental retinal detachment in rodents.. Retinal detachment was created in rats by subretinal injection of hyaluronic acid. The animals were treated daily with vehicle or TUDCA (500 mg/kg). TUNEL staining was used to evaluate cell death. Photoreceptor loss was evaluated by measuring the relative thickness of the outer nuclear layer (ONL). Macrophage recruitment, oxidative stress, cytokine levels, and caspase levels were also quantified. Three days after detachment, TUDCA decreased the number of TUNEL-positive cells compared to vehicle (651±68/mm(2) vs. 1314±68/mm(2), P = 0.001) and prevented the reduction of ONL thickness ratio (0.84±0.03 vs. 0.65±0.03, P = 0.002). Similar results were obtained after 5 days of retinal detachment. Macrophage recruitment and expression levels of TNF-a and MCP-1 after retinal detachment were not affected by TUDCA treatment, whereas increases in activity of caspases 3 and 9 as well as carbonyl-protein adducts were almost completely inhibited by TUDCA treatment.. Systemic administration of TUDCA preserved photoreceptors after retinal detachment, and was associated with decreased oxidative stress and caspase activity. TUDCA may be used as a novel therapeutic agent for preventing vision loss in diseases that are characterized by photoreceptor detachment.

Topics: Animals; Antigens, CD; Antigens, Differentiation, Myelomonocytic; Apoptosis; Blotting, Western; Caspases; Chemokine CCL2; Endoplasmic Reticulum Stress; Enzyme-Linked Immunosorbent Assay; Hyaluronic Acid; In Situ Nick-End Labeling; Male; Oxidation-Reduction; Photoreceptor Cells, Vertebrate; Protein Carbonylation; Rats; Rats, Inbred BN; Reactive Oxygen Species; Retinal Detachment; Taurochenodeoxycholic Acid; Tumor Necrosis Factor-alpha

Secretin induces bicarbonate-rich hydrocholeresis in healthy individuals, but not in untreated patients with primary biliary cirrhosis (PBC). Ursodeoxycholic acid (UDCA)--the first choice treatment for PBC--restores the secretin response. Compared with humans, secretin has poor effect in experimental normal-rat models with biliary drainage, although it may elicit hydrocholeresis when the bile-acid pool is maintained. In view of the benefits of UDCA in PBC, we used normal-rat models to unravel the acute contribution of UDCA (and/or taurine-conjugated TUDCA) for eliciting the biliary secretin response.. Intravascular and/or intrabiliary administration of agonists and inhibitors was performed in normal rats with biliary monitoring. Secretin/bile-acid interplay was analyzed in 3D cultured rat cholangiocytes that formed expansive cystic structures with intralumenal hydroionic secretion.. In vivo, secretin stimulates hydrocholeresis upon UDCA/TUDCA infusion, but does not modify the intrinsic hypercholeretic effect of dehydrocholic acid (DHCA). The former effect is dependent on microtubule polymerization, and involves PKCα, PI3K and MEK pathways, as shown by colchicine (i.p.) and retrograde biliary inhibitors. In vitro, while secretin alone accelerates the spontaneous expansion of 3D-cystic structures, this effect is enhanced in the presence of TUDCA, but not UDCA or DHCA. Experiments with inhibitors and Ca(2+)-chelator confirmed that the synergistic effect of secretin plus TUDCA involves microtubules, intracellular Ca(2+), PKCα, PI3K, PKA and MEK pathways. Gene silencing also demonstrated the involvement of the bicarbonate extruder Ae2.. UDCA is conjugated in order to promote secretin-stimulated hydrocholeresis in rats through Ae2, microtubules, intracellular Ca(2+), PKCα, PI3K, PKA, and MEK.

Topics: Animals; Anion Transport Proteins; Antiporters; Bile; Cells, Cultured; Choledochal Cyst; Dehydrocholic Acid; Gene Silencing; Humans; Liver Cirrhosis, Biliary; Male; Microtubules; Mitogen-Activated Protein Kinase Kinases; Models, Biological; Phosphatidylinositol 3-Kinases; Polymerization; Protein Kinase C; Rats; Rats, Wistar; Secretin; SLC4A Proteins; Taurine; Taurochenodeoxycholic Acid; Ursodeoxycholic Acid

Cholestatic liver injury following extra- or intrahepatic bile duct obstruction causes nonparenchymal cell proliferation and matrix deposition leading to end-stage liver disease and cirrhosis. In cholestatic conditions, nitric oxide (NO) is mainly produced by a hepatocyte-inducible NO synthase (iNOS) as a result of enhanced inflow of endotoxins to the liver and also by accumulation of bile salts in hepatocytes and subsequent hepatocellular injury. This study was aimed to investigate the role of NO and S-nitrosothiol (SNO) homeostasis in the development of hepatocellular injury during cholestasis induced by bile duct ligation (BDL) in rats. Male Wistar rats (200-250 g) were divided into four groups (n=10 each), including sham-operated (SO), bile duct-ligated (BDL), tauroursodeoxycholic acid (TUDCA, 50 mg/kg) and S-methylisothiourea (SMT, 25 mg/kg) treated. After 7 days, BDL rats showed elevated serum levels of gamma-glutamiltranspeptidase, aspartate aminotransferase, alanine aminotransferase, LDH, and bilirubin, bile duct proliferation and fibrosis, compared with the SO group. TUDCA treatment did not significantly alter these parameters, but the iNOS inhibitor SMT ameliorated hepatocellular injury, as shown by lower levels of circulating hepatic enzymes and bilirubin, and a decreased grade of bile duct proliferation and fibrosis. Both TUDCA and SMT treatments reversed Mrp2 canalicular pump expression to control levels. However, only SMT treatment significantly lowered the increased levels of plasma NO and S-nitrosation (S-nitrosylation) of liver proteins in BDL rats. Moreover, BDL resulted in a reduction of the S-nitrosoglutathione reductase (GSNOR/Adh5) enzymatic activity and a downregulation of the GSNOR/Adh5 mRNA expression that was reverted by SMT, but not TUDCA, treatment. A total of 25 liver proteins, including S-adenosyl methionine synthetase, betaine-homocysteine S-methyltransferase, Hsp90 and protein disulfide isomerase, were found to be S-nitrosated in BDL rats. In conclusion, the inhibition of NO production during induced cholestasis ameliorates hepatocellular injury. This effect is in part mediated by the improvement of cell proficiency in maintaining SNO homeostasis.

Topics: Aldehyde Oxidoreductases; Animals; ATP-Binding Cassette Transporters; Bile Ducts; Cholagogues and Choleretics; Cholestasis; Down-Regulation; Enzyme Inhibitors; Homeostasis; Isothiuronium; Ligation; Liver; Male; Nitric Oxide; Nitrosation; Proteins; Rats; Rats, Wistar; RNA, Messenger; S-Nitrosothiols; Taurochenodeoxycholic Acid

Recent evidence suggests that endoplasmic reticulum (ER) stress provoked under diabetic conditions augments the expression of scavenger receptors on macrophages, promoting the uptake of oxidized low-density lipoprotein uptake and atherogenesis. The aim of the present study was to test the hypothesis that the chemical chaperone tauroursodeoxycholic acid (TUDCA) attenuates lipid accumulation in macrophages subjected to ER stress.. Cultured human macrophages were subjected to ER stress by treating them with tunicamycin. Lipid uptake by macrophages subjected to ER stress in the presence or absence of TUDCA was assessed by oil red O staining and by assessing the cellular uptake of Dil-oxidized low-density lipoprotein by fluorescence measurement. Protein levels and phosphorylation status of ER stress markers, insulin-signaling molecules, and scavenger receptor were assessed by Western blotting.. Treatment of cultured human macrophages with the ER stressor tunicamycin caused an increase in the protein levels of cluster of differentiation 36 (CD-36) and augmentation of lipid uptake both of which were inhibited by TUDCA. TUDCA treatment inhibited tunicamycin-induced ER stress as evidenced by the attenuation of phosphorylation of eukaryotic translation initiation factor-2a and glucose reactive protein-78. In addition, TUDCA improved insulin signaling in macrophages by augmenting Akt phosphorylation and blunting c-Jun N-terminal kinase activity.. Inhibition of macrophage ER stress may represent a potential strategy in preventing atherogenesis under diabetic conditions.

Topics: Blotting, Western; CD36 Antigens; Cells, Cultured; Endoplasmic Reticulum; Humans; Insulin; Lipid Metabolism; Lipoproteins, LDL; Macrophages; Phosphorylation; Signal Transduction; Taurochenodeoxycholic Acid; Tunicamycin

The exposure to acute or chronic endoplasmic reticulum (ER) stress has been known to induce dysfunction of islets, leading to apoptosis. The reduction of ER stress in islet isolation for transplantation is critical for islet protection. In this study, we investigated whether tauroursodeoxycholate (TUDCA) could inhibit ER stress induced by thapsigargin, and restore the decreased glucose stimulation index of islets. In pig islets, thapsigargin decreased the insulin secretion by high glucose stimulation in a time-dependent manner (1h, 1.35+/-0.16; 2h, 1.21+/-0.13; 4h, 1.17+/-0.16 vs. 0h, 1.81+/-0.15, n=4, p<0.05, respectively). However, the treatment of TUDCA restored the decreased insulin secretion index induced by thapsigargin (thapsigargin, 1.25+/-0.12 vs. thapsigargin+TUDCA, 2.13+/-0.19, n=5, p<0.05). Furthermore, the culture of isolated islets for 24h with TUDCA significantly reduced the rate of islet regression (37.4+/-5.8% vs. 14.5+/-6.4%, n=12, p<0.05). The treatment of TUDCA enhanced ATP contents in islets (27.2+/-3.2pmol/20IEQs vs. 21.7+/-2.8pmol/20IEQs, n=9, p<0.05). The insulin secretion index by high glucose stimulation is also increased by treatment of TUDCA (2.42+/-0.15 vs. 1.92+/-0.12, n=12, p<0.05). Taken together, we suggest that TUDCA could be a useful agent for islet protection in islet isolation for transplantation.

Topics: Adenosine Triphosphate; Animals; Cytoprotection; Endoplasmic Reticulum; Glucose; Insulin; Insulin Secretion; Islets of Langerhans; Islets of Langerhans Transplantation; Stress, Physiological; Swine; Taurochenodeoxycholic Acid

The aim of this study was to investigate the suppressing effects of systemically administered ursodeoxycholic acid (UDCA) and tauroursodeoxycholic acid (TUDCA) on choroidal neovascularization (CNV) in a laser-treated rat model.. CNV was induced by argon laser photocoagulation in the right eye of each animal. UDCA 500 mg/kg, TUDCA 100 mg/kg, or vehicle was intraperitoneally injected at 24 h before and daily after laser treatment. Fourteen days after laser treatment, fluorescein angiography was performed to evaluate leakage from CNV and eyes were enucleated for histologic evaluation. Vascular endothelial growth factor (VEGF) levels in the retina were measured using enzyme-linked immunosorbent assay at 3 days after laser treatment and were compared between the UDCA, TUDCA, and control groups.. The proportion of CNV lesions showing clinically significant fluorescein leakage was lower in the UDCA and TUDCA groups (42%, P = 0.0124; and 46%, P = 0.0292) than in the control group (67%). CNV lesion dimensions including CNV area and CNV/choroid thickness ratio were also significantly reduced in the UDCA and TUDCA groups (7,664 +/- 630 microm(2), P < 0.001 and 8,558 +/- 570 microm(2), P < 0.001; 2.35 +/- 0.16, P = 0.026 and 2.27 +/- 0.15, P = 0.003) compared with the control group (12,147 +/- 661 microm(2) and 3.10 +/- 0.27). The VEGF level in the retina after laser treatment was lower in the TUDCA group than that in the control group (9.0 +/- 2.7 pg/mg vs. 29.4 +/- 8.2 pg/mg, P = 0.032), whereas the UDCA group showed no difference.. The systemic administration of UDCA and TUDCA suppressed laser-induced CNV formation in rats, which might be associated with anti-inflammatory action. The result indicates that UDCA and TUDCA are potential candidate drugs for the treatment of many CNV-related retinal diseases, including age-related macular degeneration.

Topics: Animals; Anti-Inflammatory Agents; Argon; Choroidal Neovascularization; Disease Models, Animal; Enzyme-Linked Immunosorbent Assay; Laser Coagulation; Male; Rats; Rats, Inbred BN; Taurochenodeoxycholic Acid; Ursodeoxycholic Acid; Vascular Endothelial Growth Factor A

Multidrug resistance associated protein 2 (Mrp2) is a canalicular transporter responsible for organic anion secretion into bile. Mrp2 activity is regulated by insertion into the plasma membrane; however, the factors that control this are not understood. Calcium (Ca(2+)) signaling regulates exocytosis of vesicles in most cell types, and the type II inositol 1,4,5-triphosphate receptor (InsP(3)R2) regulates Ca(2+) release in the canalicular region of hepatocytes. However, the role of InsP(3)R2 and of Ca(2+) signals in canalicular insertion and function of Mrp2 is not known. The aim of this study was to determine the role of InsP(3)R2-mediated Ca(2+) signals in targeting Mrp2 to the canalicular membrane. Livers, isolated hepatocytes, and hepatocytes in collagen sandwich culture from wild-type (WT) and InsP(3)R2 knockout (KO) mice were used for western blots, confocal immunofluorescence, and time-lapse imaging of Ca(2+) signals and of secretion of a fluorescent organic anion. Plasma membrane insertion of green fluorescent protein (GFP)-Mrp2 expressed in HepG2 cells was monitored by total internal reflection microscopy. InsP(3)R2 was concentrated in the canalicular region of WT mice but absent in InsP(3)R2 KO livers, whereas expression and localization of InsP(3)R1 was preserved, and InsP(3)R3 was absent from both WT and KO livers. Ca(2+) signals induced by either adenosine triphosphate (ATP) or vasopressin were impaired in hepatocytes lacking InsP(3)R2. Canalicular secretion of the organic anion 5-chloromethylfluorescein diacetate (CMFDA) was reduced in KO hepatocytes, as well as in WT hepatocytes treated with 1,2-bis(o-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid (BAPTA). Moreover, the choleretic effect of tauroursodeoxycholic acid (TUDCA) was impaired in InsP(3)R2 KO mice. Finally, ATP increased GFP-Mrp2 fluorescence in the plasma membrane of HepG2 cells, and this also was reduced by BAPTA.. InsP(3)R2-mediated Ca(2+) signals enhance organic anion secretion into bile by targeting Mrp2 to the canalicular membrane.

Topics: Adenosine Triphosphate; Animals; Bile; Bilirubin; Calcium; Calcium Signaling; Egtazic Acid; Hepatocytes; Inositol 1,4,5-Trisphosphate Receptors; Liver; Male; Mice; Mice, Knockout; Multidrug Resistance-Associated Protein 2; Multidrug Resistance-Associated Proteins; Protein Isoforms; Taurochenodeoxycholic Acid

Endoplasmic reticulum (ER) stress leads to accumulation of un- or misfolded proteins inside the ER and initiates the unfolded protein response (UPR). Several UPR components are physiologically involved in pancreatic development and are pathophysiologically activated during acute pancreatitis. However, the exact role of ER stress in exocrine pancreatic acini is mainly unclear. The present study examined the effects of tauroursodeoxycholic acid (TUDCA), a known ER chaperone, on acinar function and UPR components. Isolated rat pancreatic acini were stimulated by increasing concentrations of cholecystokinin (CCK-8) with or without preincubation of TUDCA. UPR components were analyzed, including chaperone binding protein (BiP), protein kinase-like ER kinase (PERK), X-box binding protein (XBP)-1, c-Jun NH(2)-terminal kinase (JNK), CCAAT/enhancer binding protein homologues protein (CHOP), caspase 3 activation, and apoptosis. In addition, TUDCA effects were measured on amylase secretion, calcium signaling, trypsin, and cathepsin B activation. TUDCA preincubation led to a significant increase in amylase secretion after CCK-8 stimulation, a 50% reduction of intracellular trypsin activation, and reduced cathepsin B activity, although the effects for cathepsin B were not statistical significant. Furthermore, TUDCA prevented the CCK-8-induced BiP upregulation, diminished PERK and JNK phosphorylation, and prohibited the expression of CHOP, caspase 3 activation and apoptosis. XBP-1 splicing was not altered. ER stress response mechanisms are activated in pancreatic inflammation. Chemical chaperones enhance enzyme secretion of pancreatic acini, reduce ER stress responses, and attenuate ER stress-associated apoptosis. These data hint new perspectives for an employment of chemical chaperones in the therapy of acute pancreatitis.

Topics: Amylases; Animals; Apoptosis; Calcium Signaling; Cathepsin B; Cholagogues and Choleretics; Dose-Response Relationship, Drug; Endoplasmic Reticulum; Enzyme Activation; Pancreas; Rats; Stress, Physiological; Taurochenodeoxycholic Acid; Trypsin

Familial Amyloidotic Polyneuropathy (FAP) is a disorder characterized by the extracellular deposition of fibrillar Transthyretin (TTR) amyloid, with a special involvement of the peripheral nerve. We had previously shown that doxycycline administered for 3 months at 40 mg/Kg/ml in the drinking water, was capable of removing TTR amyloid deposits present in stomachs of old TTR-V30M transgenic mice; the removal was accompanied by a decrease in extracellular matrix remodeling proteins that accompany fibrillar deposition, but not of non-fibrillar TTR deposition and/or markers associated with pre-fibrillar deposits. On the other hand, Tauroursodeoxycholic acid (TUDCA), a biliary acid, administrated to the same mouse model was shown to be effective at lowering deposited non-fibrillar TTR, as well as the levels of markers associated with pre-fibrillar TTR, but only at young ages. In the present work we evaluated different doxycycline administration schemes, including different periods of treatment, different dosages and different FAP TTR V30M animal models. Evaluation included CR staining, immunohistochemistry for TTR, metalloproteinase 9 (MMP-9) and serum amyloid P component (SAP). We determined that a minimum period of 15 days of treatment with a 8 mg/Kg/day dosage resulted in fibril removal. The possibility of intermittent treatments was also assessed and a maximum period of 15 days of suspension was determined to maintain tissues amyloid-free. Combined cycled doxycycline and TUDCA administration to mice with amyloid deposition, using two different concentrations of both drugs, was more effective than either individual doxycycline or TUDCA, in significantly lowering TTR deposition and associated tissue markers. The observed synergistic effect of doxycycline/TUDCA in the range of human tolerable quantities, in the transgenic TTR mice models prompts their application in FAP, particularly in the early stages of disease.

Topics: Amyloid Neuropathies, Familial; Animals; Biglycan; Biomarkers; Blotting, Western; Chondroitin Sulfates; Disease Models, Animal; Dose-Response Relationship, Drug; Doxycycline; Drug Administration Schedule; Drug Synergism; Endoplasmic Reticulum Chaperone BiP; Extracellular Matrix Proteins; Heat-Shock Proteins; Immunohistochemistry; Matrix Metalloproteinase 9; Mice; Prealbumin; Proteoglycans; Stomach; Taurochenodeoxycholic Acid

Obesity impairs adiponectin expression, assembly, and secretion, yet the underlying mechanisms remain elusive. The aims of this study were 1) to determine the molecular mechanisms by which obesity impairs adiponectin multimerization and stability, and 2) to determine the potential role of disulfide-bond-A oxidoreductase-like protein (DsbA-L), a recently identified adiponectin interactive protein that promotes adiponectin multimerization and stability in obesity-induced endoplasmic reticulum (ER) stress and adiponectin downregulation.. Tauroursodeoxycholic acid (TUDCA), a chemical chaperone that alleviates ER stress, was used to study the mechanism underlying obesity-induced adiponectin downregulation in db/db mice, high-fat diet-induced obese mice, and in ER-stressed 3T3-L1 adipocytes. The cellular levels of DsbA-L were altered by RNAi-mediated suppression or adenovirus-mediated overexpression. The protective role of DsbA-L in obesity- and ER stress-induced adiponectin downregulation was characterized.. Treating db/db mice and diet-induced obese mice with TUDCA increased the cellular and serum levels of adiponectin. In addition, inducing ER stress is sufficient to downregulate adiponectin levels in 3T3-L1 adipocytes, which could be protected by treating cells with the autophagy inhibitor 3-methyladenine or by overexpression of DsbA-L.. ER stress plays a key role in obesity-induced adiponectin downregulation. In addition, DsbA-L facilitates adiponectin folding and assembly and provides a protective effect against ER stress-mediated adiponectin downregulation in obesity.

Topics: 3T3 Cells; Adipocytes; Adiponectin; Adipose Tissue, White; Animals; Autophagy; Cell Differentiation; Down-Regulation; Drug Tolerance; Endoplasmic Reticulum; Gene Expression Regulation; Insulin; Male; Mice; Mice, Obese; Obesity; Reference Values; Taurochenodeoxycholic Acid

Ursodeoxycholic acid is widely used as a therapeutic agent for the treatment of cholestatic liver diseases. In these hepatopathies, the bile secretory failure produces accumulation of endogenous, tensioactive bile salts, leading to plasma membrane damage and, eventually, hepatocellular lysis. In the present study, we analyzed the capacity of the ursodeoxycholic acid endogenous metabolite, tauroursodeoxycholate (TUDC), to stabilize the hepatocellular plasma membrane against its transition to the micellar phase induced by the tensioactive bile salt taurochenodeoxycholate (TCDC), the main endogenous bile salt accumulated in cholestasis. The disruption of the plasma membrane was evaluated (i) in isolated hepatocytes, through the release of the enzyme lactate dehydrogenase to the incubation medium and (ii) in isolated plasma membranes, through the self-quenching assay of the membranotropic probe octadecylrhodamine B; this assay allows for detergent-induced transition from membrane bilayer to micelle to be monitored. Our results showed that isolated hepatocytes treated with TUDC are more resistant to TCDC-induced cell lysis. When this effect was evaluated in isolated plasma membranes, the TCDC concentration necessary to reach half of the transition from bilayer to micelle was increased by 22% (p<0.05). This difference remained even when TUDC was removed from the incubation medium before adding TCDC, thus indicating that TUDC exerted its effect directly on the plasma membrane. When the same experiments were carried out using the non-ionic detergent TX-100 or the cholesterol-complexing detergent digitonin, no protective effect was observed. In conclusion, TUDC prevents selectively the bilayer to micelle transition of the hepatocellular plasma membrane induced by hydrophobic bile salts that typically build up and accumulate in cholestatic processes. Our results suggest that formation of a complex between negatively charged TUDC and cholesterol in the membrane favours repulsion of negatively charged detergent bile salts, thus providing a basis for the understanding of the TUDC protective effects.

Topics: Animals; Cell Death; Cell Membrane; Detergents; Digitonin; Hepatocytes; Lipid Bilayers; Male; Micelles; Osmosis; Phase Transition; Polyethylene Glycols; Rats; Solubility; Taurochenodeoxycholic Acid

Amyloid-β (Aβ) peptide- induced neurotoxicity is typically associated with apoptosis. In previous studies, we have shown that tauroursodeoxycholic acid (TUDCA), an endogenous anti-apoptotic bile acid, modulates Aβ-induced apoptosis. Here, we investigated stress signaling events triggered by soluble Aβ and further explored alternative pathways of neuroprotection by TUDCA in differentiated rat neuronal-like PC12 cells. Morphologic evaluation of apoptosis confirmed that Aβ-induced nuclear fragmentation was prevented by TUDCA. In addition, Aβ exposure resulted in activation of the early stress c-Jun N-terminal kinase (JNK) pathway, JNK nuclear translocation, and caspase-2 activation. Knock-down experiments of JNK established caspase-2 as a specific downstream target of JNK in Aβ-induced apoptosis. Furthermore, active caspase-2 cleaved golgin-160 and was localized to the Golgi complex. Importantly, TUDCA abrogated Aβ-induced JNK/caspase-2 signaling. In conclusion, we show that JNK is the proximal stress sensor for soluble Aβ-induced toxicity, which translocates to the nucleus, activates caspase-2, and is strongly modulated by TUDCA in PC12 neuronal cells. Active caspase-2 cleaves golgin-160, suggesting caspase-2-dependent transduction of Aβ apoptotic signaling through the Golgi complex. These data provide new information linking apoptotic properties of Aβ peptide to distinct subcellular mechanisms of toxicity. Further characterization of this signaling pathway and exact targets of modulation are likely to provide new perspectives for modulation of amyloid-induced apoptosis by TUDCA.

Topics: Amyloid beta-Peptides; Animals; Apoptosis; Caspase 2; Cholagogues and Choleretics; Drug Interactions; Enzyme Inhibitors; Gene Expression Regulation, Enzymologic; JNK Mitogen-Activated Protein Kinases; L-Lactate Dehydrogenase; PC12 Cells; Rats; Signal Transduction; Taurochenodeoxycholic Acid; Time Factors

MicroRNAs (miRs or miRNAs) regulate several biological processes in the cell. However, evidence for miRNAs that control the differentiation program of specific neural cell types has been elusive. Recently, we have shown that apoptosis-associated factors, such as p53 and caspases participate in the differentiation process of mouse neural stem (NS) cells. To identify apoptosis-associated miRNAs that might play a role in neuronal development, we performed global miRNA expression profiling experiments in NS cells. Next, we characterized the expression of proapoptotic miRNAs, including miR-16, let-7a and miR-34a in distinct models of neural differentiation, including mouse embryonic stem cells, PC12 and NT2N cells. In addition, the expression of antiapoptotic miR-19a and 20a was also evaluated.. The expression of miR-16, let-7a and miR-34a was consistently upregulated in neural differentiation models. In contrast, expression of miR-19a and miR-20a was downregulated in mouse NS cell differentiation. Importantly, differential expression of specific apoptosis-related miRNAs was not associated with increased cell death. Overexpression of miR-34a increased the proportion of postmitotic neurons of mouse NS cells.. In conclusion, the identification of miR-16, let-7a and miR-34a, whose expression patterns are conserved in mouse, rat and human neural differentiation, implicates these specific miRNAs in mammalian neuronal development. The results provide new insights into the regulation of neuronal differentiation by apoptosis-associated miRNAs.

Topics: Animals; Apoptosis; Cell Differentiation; Cell Line; Cluster Analysis; Flow Cytometry; Gene Expression Profiling; Gene Expression Regulation; Humans; Mice; MicroRNAs; Mitosis; Neurogenesis; Neuroglia; Neurons; Rats; Stem Cells; Taurochenodeoxycholic Acid

Paraquat, a quaternary nitrogen herbicide, is a highly toxic pro-oxidant that causes multiorgan failure including that of the heart via generation of reactive oxygen species, although the underlying mechanism has not been well elucidated. This study examined the influence of cardiac-specific overexpression of catalase, an antioxidant detoxifying H(2)O(2), on paraquat-induced myocardial geometric and functional alterations, with a focus on ER stress. FVB and catalase transgenic mice were administered paraquat for 48h. Myocardial geometry, contractile function, apoptosis, and ER stress were evaluated using echocardiography, edge detection, caspase-3 activity, and immunoblotting. Our results revealed that paraquat treatment significantly enlarged left ventricular (LV) end diastolic and systolic diameters; increased LV mass and resting myocyte length; reduced fractional shortening, cardiomyocyte peak shortening, and maximal velocity of shortening/relengthening; and prolonged relengthening duration in the FVB group. Whereas the catalase transgene itself did not alter myocardial geometry and function, it mitigated or significantly attenuated paraquat-elicited myocardial geometric and functional changes. Paraquat promoted overt apoptosis and ER stress as evidenced by increased caspase-3 activity, apoptosis, and ER stress markers including Bax, Bcl-2, GADD153, calregulin, and phosphorylated JNK, IRE1α, and eIF2α; all were ablated by the catalase transgene. Paraquat-induced cardiomyocyte dysfunction was mitigated by the ER stress inhibitor tauroursodeoxycholic acid. Moreover, the JNK inhibitor SP600125 reversed paraquat-induced ER stress as evidenced by enhanced GADD153 and IRE1α phosphorylation. Taken together, these data revealed that catalase may rescue paraquat-induced myocardial geometric and functional alteration possibly by alleviating JNK-mediated ER stress.

Topics: Animals; Anthracenes; Apoptosis; Calreticulin; Caspase 3; Catalase; DNA-Binding Proteins; Echocardiography; Endoplasmic Reticulum; Endoribonucleases; Enzyme Assays; Herbicides; JNK Mitogen-Activated Protein Kinases; Male; Mice; Mice, Transgenic; Myocardial Contraction; Myocardium; Myocytes, Cardiac; Paraquat; Phosphorylation; Protein Serine-Threonine Kinases; Taurochenodeoxycholic Acid; Transcription Factor CHOP; Transcription Factors; Up-Regulation

During partial hepatectomy, ischemia-reperfusion (I/R) is commonly applied in clinical practice to reduce blood flow. Steatotic livers show impaired regenerative response and reduced tolerance to hepatic injury. We examined the effects of tauroursodeoxycholic acid (TUDCA) and 4-phenyl butyric acid (PBA) in steatotic and non-steatotic livers during partial hepatectomy under I/R (PH+I/R). Their effects on the induction of unfolded protein response (UPR) and endoplasmic reticulum (ER) stress were also evaluated. We report that PBA, and especially TUDCA, reduced inflammation, apoptosis and necrosis, and improved liver regeneration in both liver types. Both compounds, especially TUDCA, protected both liver types against ER damage, as they reduced the activation of two of the three pathways of UPR (namely inositol-requiring enzyme and PKR-like ER kinase) and their target molecules caspase 12, c-Jun N-terminal kinase and C/EBP homologous protein-10. Only TUDCA, possibly mediated by extracellular signal-regulated kinase upregulation, inactivated glycogen synthase kinase-3β. This is turn, inactivated mitochondrial voltage-dependent anion channel, reduced cytochrome c release from the mitochondria and caspase 9 activation and protected both liver types against mitochondrial damage. These findings indicate that chemical chaperones, especially TUDCA, could protect steatotic and non-steatotic livers against injury and regeneration failure after PH+I/R.

Topics: Activating Transcription Factor 6; Animals; Caspase 12; Cytochromes c; Endoplasmic Reticulum; Fatty Liver; Glycogen Synthase Kinase 3; Glycogen Synthase Kinase 3 beta; Heat-Shock Proteins; Hepatectomy; JNK Mitogen-Activated Protein Kinases; Liver; Mitochondria; Phenylbutyrates; Rats; Rats, Zucker; Reperfusion Injury; Taurochenodeoxycholic Acid; Unfolded Protein Response; Voltage-Dependent Anion Channels

Leptin has not evolved as a therapeutic modality for the treatment of obesity due to the prevalence of leptin resistance in a majority of the obese population. Nevertheless, the molecular mechanisms of leptin resistance remain poorly understood. Here, we show that increased endoplasmic reticulum (ER) stress and activation of the unfolded protein response (UPR) in the hypothalamus of obese mice inhibits leptin receptor signaling. The genetic imposition of reduced ER capacity in mice results in severe leptin resistance and leads to a significant augmentation of obesity on a high-fat diet. Moreover, we show that chemical chaperones, 4-phenyl butyric acid (PBA), and tauroursodeoxycholic acid (TUDCA), which have the ability to decrease ER stress, act as leptin-sensitizing agents. Taken together, our results may provide the basis for a novel treatment of obesity.

Topics: Animals; Endoplasmic Reticulum; Hypothalamus; Leptin; Mice; Mice, Inbred C57BL; Mice, Obese; Obesity; Phenylbutyrates; Receptors, Leptin; Signal Transduction; Taurochenodeoxycholic Acid; Tunicamycin

The vasculotropic E22Q mutant of the amyloid-beta (Abeta) peptide is associated with hereditary cerebral hemorrhage with amyloidosis Dutch type. The cellular mechanism(s) of toxicity and nature of the AbetaE22Q toxic assemblies are not completely understood. Comparative assessment of structural parameters and cell death mechanisms elicited in primary human cerebral endothelial cells by AbetaE22Q and wild-type Abeta revealed that only AbetaE22Q triggered the Bax mitochondrial pathway of apoptosis. AbetaE22Q neither matched the fast oligomerization kinetics of Abeta42 nor reached its predominant beta-sheet structure, achieving a modest degree of oligomerization with a secondary structure that remained a mixture of beta and random conformations. The endogenous molecule tauroursodeoxycholic acid (TUDCA) was a strong modulator of AbetaE22Q-triggered apoptosis but did not significantly change the secondary structures and fibrillogenic propensities of Abeta peptides. These data dissociate the pro-apoptotic properties of Abeta peptides from their distinct mechanisms of aggregation/fibrillization in vitro, providing new perspectives for modulation of amyloid toxicity.

Topics: Amyloid beta-Peptides; Apoptosis; bcl-2-Associated X Protein; Brain; Cells, Cultured; Cerebellum; Cytochromes c; Endothelial Cells; Endothelium, Vascular; Humans; Microvessels; Mitochondria; Mutation; Protein Binding; Protein Multimerization; Protein Structure, Secondary; Protein Transport; Taurochenodeoxycholic Acid

Clostridium sordellii lethal toxin (TcsL) belongs to the family of clostridial glucosylating toxins. TcsL exhibits glucosyltransferase activity to inactivate Rho and Ras proteins. On cultured cells, TcsL causes actin reorganization ("cytopathic effect") and apoptotic cell death ("cytotoxic effect"). This study is based on the concept that the cytotoxic effects of TcsL depend on the glucosylation of critical substrate proteins rather than on the glucosyltransferase activity per se. The cytotoxic effects of TcsL depend on the glucosyltransferase activity of TcsL, as neither chemically inactivated TcsL nor a glucosyltransferase-deficient mutant version of TcsL caused it. The TcsL homologous toxin B from Clostridium difficile serotype F strain 1470 (TcdBF) also failed to cause cytotoxic effects. Correlation of the toxins' respective protein substrate specificities highlighted (H/K/N)Ras as critical substrate proteins for the cytotoxic effects. (H/K/N)Ras are critical upstream regulators of phosphatidylinositide 3'-OH kinase (PI3K)/Akt survival signaling. Tauroursodeoxycholic acid (TUDCA) classified to activate PI3K/Akt signaling downstream of apoptosis-inducing stimuli prevented the cytotoxic effects of TcsL. In conclusion, (H/K/N)Ras glucosylation and subsequent inhibition of PI3K/Akt signaling are critical for the cytotoxic effects of TcsL.

Topics: Animals; Bacterial Toxins; Caspase 3; Cell Death; Cell Line, Tumor; Cell Survival; Glycosylation; Glycosyltransferases; Leukemia, Basophilic, Acute; Phosphatidylinositol 3-Kinases; Phosphoinositide-3 Kinase Inhibitors; Protein Structure, Tertiary; Proto-Oncogene Proteins c-akt; Rats; Signal Transduction; Taurochenodeoxycholic Acid

Endoplasmic reticulum (ER) stress is associated with obesity-induced insulin resistance, yet the underlying mechanisms remain to be fully elucidated. Here we show that ER stress-induced insulin receptor (IR) down-regulation may play a critical role in obesity-induced insulin resistance. The expression levels of IR are negatively associated with the ER stress marker C/EBP homologous protein (CHOP) in insulin target tissues of db/db mice and mice fed a high-fat diet. Significant IR down-regulation was also observed in fat tissue of obese human subjects and in 3T3-L1 adipocytes treated with ER stress inducers. ER stress had little effect on IR tyrosine phosphorylation per se but greatly reduced IR downstream signaling. The ER stress-induced reduction in IR cellular levels was greatly alleviated by the autophagy inhibitor 3-methyladenine but not by the proteasome inhibitor N-benzoyloxycarbonyl (Z)-Leu-Leu-leucinal (MG132). Inhibition of autophagy prevented IR degradation but did not rescue IR downstream signaling, consistent with an adaptive role of autophagy in response to ER stress-induced insulin resistance. Finally, chemical chaperone treatment protects cells from ER stress-induced IR degradation in vitro and obesity-induced down-regulation of IR and insulin action in vivo. Our results uncover a new mechanism underlying obesity-induced insulin resistance and shed light on potential targets for the prevention and treatment of obesity-induced insulin resistance and type 2 diabetes.

Topics: 3T3-L1 Cells; Adipocytes; Animals; Autophagy; Disease Models, Animal; Down-Regulation; Endoplasmic Reticulum; Humans; Insulin Resistance; Leupeptins; Mice; Mice, Inbred Strains; Obesity; Phosphorylation; Receptor, Insulin; Taurochenodeoxycholic Acid; Tyrosine

Virulent strains of Clostridium sordellii cause gangrenous myonecrosis in humans. The released lethal toxin (TcsL) and hemorrhagic toxin (TcsH) are regarded as the major virulence factors. TcsL inactivates low molecular weight GTP-binding proteins of the Rho/Ras subfamilies by monoglucosylation. In cultured cell lines, glucosylation, i.e., inactivation of Rho/Ras proteins, results in actin reorganization ("cytopathic effect") and apoptotic cell death ("cytotoxic effect"). Apoptotic cell death induced by TcsL is suggested to be based on inhibition of the phosphoinositide 3-kinase (PI3K)/Akt-survival pathway. In this study, we analyze the critical role of PI3K/Akt signaling in TcsL-induced apoptosis using the antiapoptotic bile acid tauroursodeoxycholic acid (TUDCA) as the pharmacological tool. TUDCA preserved the TcsL-induced decrease of the cellular level of phospho-Akt, suggesting that TUDCA activated PI3K/Akt signaling downstream of inhibited Ras signaling. TcsL-induced apoptosis was prevented by TUDCA treatment. The antiapoptotic effect of TUDCA was abolished by the PI3K inhibitor LY294002 and the Akt inhibitor, showing that the antiapoptotic effect depends on PI3K/Akt signaling. Inhibition of Ras/Rho signaling by TcsL resulted in activation of p38 MAP kinase. Inhibition of p38 MAP kinase by SB203580 protected cells from TcsL-induced apoptosis. TUDCA induced activation of p38 MAP kinase as well, an aspect of the TUDCA effects that most likely did not contribute to its antiapoptotic activity. Due to its antiapoptotic activity, TUDCA is under investigation for its potential application as a therapeutic modulator of apoptosis-related diseases. TUDCA may represent a new concept for the treatment of disease associated with toxigenic C. sordellii.

Topics: Animals; Apoptosis; Bacterial Toxins; Cell Line; Chromones; Clostridium Infections; Clostridium sordellii; Enzyme Activation; Enzyme Inhibitors; HeLa Cells; Humans; Imidazoles; Mice; Models, Biological; Morpholines; p38 Mitogen-Activated Protein Kinases; Phosphoinositide-3 Kinase Inhibitors; Proto-Oncogene Proteins c-akt; Pyridines; ras Proteins; Signal Transduction; Taurochenodeoxycholic Acid

Depending on the nature of chemical structures, different bile acids exhibit distinct biological effects. Their therapeutic efficacy has been widely demonstrated in various liver diseases, suggesting that they might protect hepatocytes against common mechanisms of liver damage. Although it has been shown to prevent apoptotic cell death in certain cell lines, bile acids significantly inhibited cell growth and induced apoptosis in cancer cells. To better understand the pharmacological potential of bile acids in cancer cells, we investigated and compared the effects of deoxycholic acid (DCA), ursodeoxycholic acid (UDCA), and their taurine-derivatives [taurodeoxycholic acid (TDCA) and tauroursodeoxycholic acid (TUDCA), respectively] on the induction of apoptosis and inhibition of cell proliferation of a human T leukemia cell line (Jurkat cells). All the bile acids tested induced a delay in cell cycle progression. Moreover, DCA markedly increased the fraction of apoptotic cells. The effects of TDCA, UDCA, and TUDCA were different from those observed for DCA. Their primary effect was the induction of necrosis. These distinctive features suggest that the hydrophobic properties of DCA play a role in its cytotoxic potential and indicate that it is possible to create new drugs useful for cancer therapy from bile acid derivatives as lead compounds.

Topics: Apoptosis; Bile Acids and Salts; Cell Cycle; Cell Division; Cell Survival; Deoxycholic Acid; Dose-Response Relationship, Drug; Flow Cytometry; G1 Phase; G2 Phase; Humans; Jurkat Cells; Leukemia, T-Cell; S Phase; Taurochenodeoxycholic Acid; Taurodeoxycholic Acid; Ursodeoxycholic Acid

Alteration in endoplasmic reticulum (ER) stress in diabetic hearts and its effect on cytoprotective signaling are unclear. Here, we examine the hypothesis that ER stress in diabetic hearts impairs phospho-glycogen synthase kinase (GSK)-3beta-mediated suppression of mitochondrial permeability transition pore (mPTP) opening, compromising myocardial response to cytoprotective signaling.. A rat model of type 2 diabetes (OLETF) and its control (LETO) were treated with tauroursodeoxycholic acid (TUDCA) (100 mg . kg(-1) . day(-1) for 7 days), an ER stress modulator. Infarction was induced by 20-min coronary occlusion and 2-h reperfusion.. Levels of ER chaperones (GRP78 and GRP94) in the myocardium and level of nonphoshopho-GSK-3beta in the mitochondria were significantly higher in OLETF than in LETO rats. TUDCA normalized levels of GRP78 and GRP94 and mitochondrial GSK-3beta in OLETF rats. Administration of erythropoietin (EPO) induced phosphorylation of Akt and GSK-3beta and reduced infarct size (% risk area) from 47.4 +/- 5.2% to 23.9 +/- 3.5% in LETO hearts. However, neither phosphorylation of Akt and GSK-3beta nor infarct size limitation was induced by EPO in OLETF rats. The threshold for mPTP opening was significantly lower in mitochondria from EPO-treated OLETF rats than in those from EPO-treated LETO rats. TUDCA restored responses of GSK-3beta, mPTP opening threshold, and infarct size to EPO receptor activation in OLETF rats. There was a significant correlation between mPTP opening threshold and phospho-GSK-3beta-to-total GSK-3beta ratio in the mitochondrial fraction.. Disruption of protective signals leading to GSK-3beta phosphorylation and increase in mitochondrial GSK-3beta are dual mechanisms by which increased ER stress inhibits EPO-induced suppression of mPTP opening and cardioprotection in diabetic hearts.

Topics: Animals; Blood Glucose; Body Weight; Calcium; Diabetes Mellitus, Type 2; Endoplasmic Reticulum; Erythropoietin; Glycogen Synthase Kinase 3; Glycogen Synthase Kinase 3 beta; Immunoblotting; Intracellular Membranes; Male; Membrane Potential, Mitochondrial; Mitochondria, Heart; Myocardial Infarction; Myocardial Reperfusion; Myocardium; Myocytes, Cardiac; Permeability; Phosphorylation; Rats; Rats, Inbred OLETF; Taurochenodeoxycholic Acid

Tauroursodeoxycholic acid (TUDCA) is a unique natural compound that acts as a potent anti-apoptotic and anti-oxidant agent, reducing cytotoxicity in several neurodegenerative diseases. Since oxidative stress, apoptosis and inflammation are associated with transthyretin (TTR) deposition in Familial Amyloidotic Polyneuropathy (FAP), we investigated the possible TUDCA therapeutical application in this disease. We show by semi-quantitative immunohistochemistry and western blotting that administration of TUDCA to a transgenic mouse model of FAP decreased apoptotic and oxidative biomarkers usually associated with TTR deposition, namely the ER stress markers BiP and eIF2alpha, the Fas death receptor and oxidation products such as 3-nitrotyrosine. Most important, TUDCA treatment significantly reduced TTR toxic aggregates in as much as 75%. Since TUDCA has no effect on TTR aggregation "in vitro", this finding points for the "in vivo" modulation of TTR aggregation by cellular responses, such as by oxidative stress, ER stress and apoptosis and prompts for the use of this safe drug in prophylactic and therapeutic measures in FAP.

Topics: Amyloid Neuropathies, Familial; Animals; Apoptosis; Disease Models, Animal; Endoplasmic Reticulum; Endoplasmic Reticulum Chaperone BiP; fas Receptor; Gastrointestinal Tract; Heat-Shock Proteins; Humans; Immunohistochemistry; Methionine; Mice; Mice, Transgenic; Molecular Chaperones; Mutant Proteins; Mutation; Oxidation-Reduction; Prealbumin; Protein Structure, Quaternary; Taurochenodeoxycholic Acid; Thermodynamics; Tyrosine

Ursodeoxycholic acid (UDCA) exerts anticholestatic effects in part by protein kinase C (PKC)-dependent mechanisms. Its taurine conjugate, TUDCA, is a cPKC alpha agonist. We tested whether protein kinase A (PKA) might contribute to the anticholestatic action of TUDCA via cooperative cPKC alpha-/PKA-dependent mechanisms in taurolithocholic acid (TLCA)-induced cholestasis.. In perfused rat liver, bile flow was determined gravimetrically, organic anion secretion spectrophotometrically, lactate dehydrogenase (LDH) release enzymatically, cAMP response-element binding protein (CREB) phosphorylation by immunoblotting, and cAMP by immunoassay. PKC/PKA inhibitors were tested radiochemically. In vitro phosphorylation of the conjugate export pump, Mrp2/Abcc2, was studied in rat hepatocytes and human Hep-G2 hepatoma cells.. In livers treated with TLCA (10 micromol/l)+TUDCA (25 micromol/l), combined inhibition of cPKC by the cPKC-selective inhibitor Gö6976 (100 nmol/l) or the non-selective PKC inhibitor staurosporine (10 nmol/l) and of PKA by H89 (100 nmol/l) reduced bile flow by 36% (p<0.05) and 48% (p<0.01), and secretion of the Mrp2/Abcc2 substrate, 2,4-dinitrophenyl-S-glutathione, by 31% (p<0.05) and 41% (p<0.01), respectively; bile flow was unaffected in control livers or livers treated with TUDCA only or TLCA+taurocholic acid. Inhibition of cPKC or PKA alone did not affect the anticholestatic action of TUDCA. Hepatic cAMP levels and CREB phosphorylation as readout of PKA activity were unaffected by the bile acids tested, suggesting a permissive effect of PKA for the anticholestatic action of TUDCA. Rat and human hepatocellular Mrp2 were phosphorylated by phorbol ester pretreatment and recombinant cPKC alpha, nPKC epsilon, and PKA, respectively, in a staurosporine-sensitive manner.. UDCA conjugates exert their anticholestatic action in bile acid-induced cholestasis in part via cooperative post-translational cPKC alpha-/PKA-dependent mechanisms. Hepatocellular Mrp2 may be one target of bile acid-induced kinase activation.

Topics: Animals; Cholagogues and Choleretics; Cholestasis; Cyclic AMP-Dependent Protein Kinases; Enzyme Activation; Humans; Liver; Male; Multidrug Resistance-Associated Protein 2; Protein Kinase C-alpha; Protein Kinase Inhibitors; Rats; Taurochenodeoxycholic Acid

Activations of death receptors and mitochondrial damage are well-described common apoptotic pathways. Recently, a novel pathway via endoplasmic reticulum (ER) stress has been reported.. We assessed the role of tauroursodeoxycholic acid (TUDCA) in inhibition of ER stress and its protective effect on advanced glycation end products (AGEs)-induced apoptosis in murine podocytes. Podocytes were incubated with increasing doses of AGEs for variable time periods. Apoptosis was quantitatively determined by flow cytometry detecting propidium iodide expression and annexin V binding simultaneously. Level of glucose-regulated protein 78 (ER stress marker) expression was determined by Western blot. Intracellular calcium concentration ([Ca(2+)](i)) was recorded by a laser confocal microscope and the Ca(2+) indicator Fluo-3 labeling.. AGEs induced podocyte apoptosis and increased the expression of glucose-regulated protein 78 in a dose- and time-dependent manner as compared with bovine serum albumin. These changes were accompanied by a rapid rise in [Ca(2+)](i) of podocytes. TUDCA was capable of abolishing AGEs-induced expression of glucose-regulated protein 78 and subsequently inhibited apoptosis in a dose-dependent manner.. We propose that ER stress plays an important role in AGEs-induced apoptosis and that TUDCA prevents apoptosis by blocking an ER stress-mediated apoptotic pathway. This novel mechanism of TUDCA action suggests new intervention methods for AGEs-induced apoptosis of mouse podocytes in diabetic nephropathy.

Topics: Animals; Apoptosis; Calcium; Endoplasmic Reticulum; Endoplasmic Reticulum Chaperone BiP; Gene Expression Regulation; Glycation End Products, Advanced; Heat-Shock Proteins; Mice; Microscopy, Confocal; Models, Biological; Molecular Chaperones; Podocytes; Taurine; Taurochenodeoxycholic Acid; Time Factors; Ursodeoxycholic Acid

In order to interpret the clinical efficacy of conjugated ursodeoxycholate (UDC) in cholesterol (Ch) gallstone patients, the Ch solubilization in mixed micelles in 40:40:32 mM tauroursodeoxycholate (TUDC):taurochenodeoxycholate (TCDC):lecithin (L) and 80:32 mM TUDC:L systems was estimated by using a model of Ch binding to mixed micelles. The Ch solubilization limit in mixed TUDC:L micelles was found to be higher than that in mixed TUDC:TCDC:L micelles. In the 80:32 mM TUDC:L system, the dissolution of the Ch pellet decreased after vesicles (liposomes) formed on the surface of the Ch pellet whereas the dissolution of microcrystalline Ch was rapid before and after vesicle formation in the solution, indicating that the total surface area of solid Ch exposed to the solution may be another important factor in inducing the dissolution of Ch gallstones. These phenomena suggest that although vesicles, occasionally formed in the bile of patients under the therapy of conjugated UDC, make a contribution to the solubilization of Ch gallstones, the model of Ch binding to mixed TUDC:L micelles can be used to estimate Ch solubility in TUDC:L system.

Topics: Chemistry, Pharmaceutical; Cholesterol; Excipients; Lecithins; Light; Liposomes; Micelles; Models, Chemical; Models, Statistical; Scattering, Radiation; Solubility; Solutions; Taurochenodeoxycholic Acid

Peroxisome proliferator-activated receptor gamma (PPARgamma) ligands inhibit cell growth and induce apoptosis in various cancer cells. Bile acids are also known to cause hepatocyte apoptosis through nuclear receptor-mediated mechanisms. The aim of this study was to examine the effect of two different bile acid species on the inhibitory action of PPARgamma in cell growth with paying attention to the role of the mitogen-activated protein kinase pathway as an underlying mechanism.. Immortalized human hepatocytes (OUMS-29) and hepatoma cells (HepG2 and Huh7) were incubated with troglitazone (TGZ), a PPARgamma ligand with or without pre-incubation of either hydrophobic glycochenodeoxycholate (GCDC) or hydrophilic tauroursodeoxycholate (TUDC).. TGZ induced cell apoptosis in all cell types, resulting in the reduction of cell viability. While pre-incubation with GCDC enhanced the apoptotic effects of TGZ, TUDC significantly attenuated it. Both bile acids enhanced p38 and c-Jun N-terminal kinase (JNK) phosphorylation in a similar way, whereas there was more drastic enhancement of extracellular signal-regulated kinase (ERK) 1/2 phosphorylation in the presence of TUDC compared to GCDC. In addition, ERK inhibitors suppressed the action of TUDC against apoptotic effect of TGZ.. This study demonstrates that TUDC exhibits anti-apoptotic and cytoprotective effects against TGZ-induced cell apoptosis, presumably through the ERK signaling pathway. We speculate that the administration of TUDC might be one of the potential strategies for the hepatotoxicity caused by TGZ.

Topics: Apoptosis; Butadienes; Cell Cycle; Cell Line, Tumor; Cell Proliferation; Cell Survival; Chromans; Cytoprotection; Glycochenodeoxycholic Acid; Hepatocytes; Humans; JNK Mitogen-Activated Protein Kinases; Ligands; Mitogen-Activated Protein Kinase 1; Mitogen-Activated Protein Kinase 3; Nitriles; p38 Mitogen-Activated Protein Kinases; Phosphorylation; PPAR gamma; Protein Kinase Inhibitors; Taurochenodeoxycholic Acid; Thiazolidinediones; Time Factors; Troglitazone

It is estimated that more than 40 different lysosomal storage disorders (LSDs) cumulatively affect one in 5000 live births, and in the majority of the LSDs, neurodegeneration is a prominent feature. Neuronal ceroid lipofuscinoses (NCLs), as a group, represent one of the most common (one in 12,500 births) neurodegenerative LSDs. The infantile NCL (INCL) is the most devastating neurodegenerative LSD, which is caused by inactivating mutations in the palmitoyl-protein thioesterase-1 (PPT1) gene. We previously reported that neuronal death by apoptosis in INCL, and in the PPT1-knockout (PPT1-KO) mice that mimic INCL, is at least in part caused by endoplasmic reticulum (ER) and oxidative stresses. In the present study, we sought to determine whether ER and oxidative stresses are unique manifestations of INCL or they are common to both neurodegenerative and non-neurodegenerative LSDs. Unexpectedly, we found that ER and oxidative stresses are common manifestations in cells from both neurodegenerative and non-neurodegenerative LSDs. Moreover, all LSD cells studied show extraordinary sensitivity to brefeldin-A-induced apoptosis, which suggests pre-existing ER stress conditions. Further, we uncovered that chemical disruption of lysosomal homeostasis in normal cells causes ER stress, suggesting a cross-talk between the lysosomes and the ER. Most importantly, we found that chemical chaperones that alleviate ER and oxidative stresses are also cytoprotective in all forms of LSDs studied. We propose that ER and oxidative stresses are common mediators of apoptosis in both neurodegenerative and non-neurodegenerative LSDs and suggest that the beneficial effects of chemical/pharmacological chaperones are exerted, at least in part, by alleviating these stress conditions.

Topics: Apoptosis; Calnexin; Catalase; Cells, Cultured; DNA-Binding Proteins; Endoplasmic Reticulum; Endoplasmic Reticulum Chaperone BiP; Gangliosidosis, GM1; Genetic Markers; Glutaredoxins; Heat-Shock Proteins; Humans; Lysosomal Storage Diseases; Lysosomal Storage Diseases, Nervous System; Lysosomes; Methylamines; Mitochondrial Proton-Translocating ATPases; Molecular Chaperones; Neuronal Ceroid-Lipofuscinoses; Nuclear Proteins; Oxidative Stress; Protein Folding; Regulatory Factor X Transcription Factors; RNA, Messenger; Superoxide Dismutase; Taurochenodeoxycholic Acid; Transcription Factors

Ursodeoxycholic acid (UDCA) is used in the therapy of cholestatic liver diseases. Apoptosis induced by toxic bile acids plays an important role in the pathogenesis of liver injury during cholestasis and appears to be mediated by the human transcription factor AP-1. We aimed to study if TUDCA can decrease taurolitholic acid (TLCA)-induced apoptosis by modulating AP-1. TLCA (20 microM) upregulated AP-1 proteins cFos (26-fold) and JunB (11-fold) as determined by quantitative real-time PCR in HepG2-Ntcp hepatoma cells. AP-1 transcriptional activity increased by 300% after exposure to TLCA. cFos and JunB expression as well as AP-1 transcriptional activity were unaffected by TUDCA (75 microM). However, TUDCA significantly decreased TLCA-induced upregulation of cFos and JunB. Furthermore, TUDCA inhibited TLCA-induced AP-1 transcriptional activity and reduced TLCA-induced apoptosis. These data suggest that reversal of bile acid-induced AP-1 activation may be relevant for the antiapoptotic effect of TUDCA in liver cells.

Topics: Apoptosis; Base Sequence; Bile Acids and Salts; Cells, Cultured; Cholagogues and Choleretics; Cholestasis; Humans; Liver Diseases; Proto-Oncogene Proteins c-fos; Proto-Oncogene Proteins c-jun; Taurochenodeoxycholic Acid; Taurolithocholic Acid; Transcription Factor AP-1

Topics: Antioxidants; Cysteine; Endoplasmic Reticulum; Hemochromatosis; Hemochromatosis Protein; Histocompatibility Antigens Class I; Homozygote; Humans; Membrane Proteins; Mutation; Reactive Oxygen Species; Taurochenodeoxycholic Acid; Tyrosine

The role of bile acids for insulin resistance in cholestatic liver disease is unknown.. The effect of taurolithocholic acid-3 sulfate (TLCS) on insulin signaling was studied in cultured rat hepatocytes and perfused rat liver.. TLCS induced insulin resistance at the level of insulin receptor (IR) beta Tyr(1158) phosphorylation, phosphoinositide (PI) 3-kinase activity and protein kinase (PK)B Ser(473) phosphorylation in cultured hepatocytes. Consistently, the insulin stimulation of the PI 3-kinase-dependent K(+) uptake, hepatocyte swelling and proteolysis inhibition was blunted by TLCS in perfused rat liver. The PKC inhibitor Go6850 and tauroursodeoxycholate (TUDC) counteracted the suppression of insulin-induced IRbeta and PKB phosphorylation by TLCS. Rapamycin and dibutyryl-cAMP, which inhibited basal signaling via mammalian target of rapamycin (mTOR), restored insulin-induced PKB- but not IRbeta phosphorylation. In livers from 7 day bile duct-ligated rats PKB Ser(473) phosphorylation was decreased by about 50%.. TLCS induces insulin resistance by a PKC-dependent suppression of insulin-induced IRbeta phosphorylation and the PI 3-kinase/PKB path. This can in part be compensated by a decrease of mTOR activity, which may release insulin-sensitive components downstream of the insulin receptor from tonic inhibition. The data suggest that retention of hydrophobic bile acids confers insulin resistance on the cholestatic liver.

Topics: Animals; Bile Acids and Salts; Bile Ducts; Cells, Cultured; Enzyme Activation; Hepatocytes; Insulin; Ligation; Liver; Liver Neoplasms, Experimental; Male; Perfusion; Phosphatidylinositol 3-Kinases; Phosphorylation; Phosphotyrosine; Protein Processing, Post-Translational; Proto-Oncogene Proteins c-akt; Rats; Rats, Wistar; Receptor, Insulin; Signal Transduction; Taurochenodeoxycholic Acid; Taurolithocholic Acid

The potential role of apoptosis in Alzheimer's disease (AD) has been an area of intense research in recent years. Ursodeoxycholic acid (UDCA) and its taurine-conjugate, tauroursodeoxycholic acid (TUDCA) are endogenous bile acids that act as potent inhibitors of apoptosis. Their therapeutic effects have been tested in many experimental pathological conditions, including neurological disorders, such as AD. TUDCA regulates precise transcriptional and post-transcriptional events that impact mitochondrial function in neurons. TUDCA not only stabilizes the mitochondrial membrane and prevents Bax translocation, inhibiting the release of cytochrome c and the activation of caspases, but also interferes with upstream factors, including cell cycle-related proteins. In addition, TUDCA is capable of inducing survival pathways. Here, we review the role of apoptosis in AD and discuss the therapeutic potential of TUDCA in treating this disease.

Topics: Alzheimer Disease; Animals; Apoptosis; Bile Acids and Salts; Cell Cycle Proteins; Humans; Models, Biological; Taurochenodeoxycholic Acid; Ursodeoxycholic Acid

Greater clinical understanding of the pivotal role of apoptosis in spinal cord injury (SCI) has led to new and innovative apoptosis-based therapies for patients with an SCI. Tauroursodeoxycholic acid (TUDCA) is a biliary acid with antiapoptotic properties. To our knowledge, this is the first study in the English language to evaluate the therapeutic efficacy of TUDCA in an experimental model of SCI. Thirty rats were randomized into three groups (sham-operated, trauma only, and trauma plus TUDCA treatment) of 10 each. In groups 2 and 3, spinal cord trauma was produced at the T8-T10 level via the Allen weight drop technique. Rats in group 3 were treated with TUDCA (200 mg/kg intraperitoneal) 1 min after trauma. The rats were killed either 24 h or 5 days after injury. The neuroprotective effect of TUDCA on injured spinal cord tissue and the effects of that agent on the recovery of hind-limb function were assessed. The efficacy of treatment was evaluated with histopathologic examination and terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick-end labeling (TUNEL) analysis. Histopathologic characteristics were analyzed by comparison of hematoxylin-and-eosin stained specimens. Neurologic evaluations were performed 24 h, 3 days, and 5 days after trauma. Hind-limb function was assessed with the inclined plane technique of Rivlin and Tator and the modified version of Tarlov's grading scale. Twenty-four hours after injury, there was a significantly higher number of apoptotic cells in the lesioned spinal cord group than in the sham-operated control group. Treatment of the rats with TUDCA significantly reduced the number of apoptotic cells (4.52+/-0.30 vs. 2.31+/-0.24 in group 2) and the degree of tissue injury. Histopathologic examination showed that group 3 rats had better spinal cord architecture compared with group 2 rats. Five days after injury, the mean inclined plane angles in groups 1, 2, and 3 were 65.50 degrees +/- 2.09, 42.00 degrees +/- 2.74, and 53.50 degrees +/- 1.36. Motor grading of the rats revealed a similar trend. These differences were statistically significant (p<0.05). The mechanism of neuroprotection in the treated rats, although not yet elucidated, may be related to the marked antiapoptotic properties of TUDCA. A therapeutic strategy using TUDCA may eventually lead to effective treatment of SCI without toxic effects in humans.

Topics: Animals; Apoptosis; Cholagogues and Choleretics; Disease Models, Animal; In Situ Nick-End Labeling; Random Allocation; Rats; Rats, Wistar; Recovery of Function; Spinal Cord Injuries; Statistics, Nonparametric; Taurochenodeoxycholic Acid; Time Factors

Cholestasis, induced by liver ischemia-reperfusion injury (IRI), is characterized by dilatation of bile canaliculi and loss of microvilli. Tauroursodeoxycholic acid (TUDCA) is an anti-cholestatic agent, modulating protein kinase C (PKC) alpha pathway. PKC reduces ischemic damage in several organs, its isoform alpha modulates ezrin, a key protein in the maintenance of cell lamellipoidal extensions. We evaluated the effects of TUDCA on cholestasis, canalicular changes and PKCalpha-ezrin expression in a rat model of liver IRI. Livers flushed and stored with Belzer solution or Belzer + 10 mm TUDCA (4 degrees C for 6 h) were reperfused (37 degrees C with O(2)) with Krebs-Ringer bicarbonate + 2.5 micromol/min of Taurocholate or TUDCA. Bile was harvested for bile flow assessment. Liver tissue was employed for Electron Microscopy (EM) and for PKCalpha and ezrin immunoblot and immunofluorescence. The same experiments were conducted with the PKCalpha inhibitor Go-6976. TUDCA-treated livers showed increased bile flow (0.25+/-0.17 vs. 0.042+/-0.02 microl/min/g liver, P<0.05) and better preservation of microvilli and bile canalicular area at EM. These effects were associated with increased PKCalpha and ezrin expression (P=0.03 and P=0.04 vs. control respectively), as also confirmed by immunofluorescence data. PKCalpha inhibition abolished these TUDCA effects. TUDCA administration during IRI reduces cholestasis and canalicular damage in the liver modulating PKCalpha-ezrin pathway.

Topics: Animals; Bile; Bile Canaliculi; Carbazoles; Cholagogues and Choleretics; Cholestasis; Cytoskeletal Proteins; Enzyme Inhibitors; L-Lactate Dehydrogenase; Liver; Male; Microscopy, Electron, Scanning; Protein Kinase C-alpha; Rats; Rats, Wistar; Reperfusion Injury; Taurochenodeoxycholic Acid

Retinitis pigmentosa (RP) is a progressive neurodegenerative disease resulting in blindness for which there is no current treatment. Although the members of the family of RP diseases differ in etiology, their outcomes are the same: apoptosis of rods and then by cones. Recently, the bile acid tauroursodeoxycholic acid (TUDCA) has been shown to have antiapoptotic properties in neurodegenerative diseases, including those of the retina. In this study the authors examined the efficacy of TUDCA on preserving rod and cone function and morphology at postnatal day 30 (P30) in the rd10 mouse, a model of RP.. Wild-type C57BL/6J and rd10 mice were systemically injected with TUDCA (500 mg/kg) every 3 days from P6 to P30 and were compared with vehicle (0.15 M NaHCO(3)). At P30, retinal function was measured with electroretinography, and morphologic preservation of the rods and cones was assessed with immunohistochemistry.. Dark-adapted electroretinographic (ERG) responses were twofold greater in rd10 mice treated with TUDCA than with vehicle, likewise light-adapted responses were twofold larger in TUDCA-treated mice than in controls at the brightest ERG flash intensities. TUDCA-treated rd10 retinas had fivefold more photoreceptors than vehicle-treated retinas. TUDCA treatments did not alter retinal function or morphology of wild-type mice when administered to age-matched mice.. TUDCA is efficacious and safe in preserving vision in the rd10 mouse model of RP when treated between P6 and P30. At P30, a developmental stage at which nearly all rods are absent in the rd10 mouse model of RP, TUDCA treatment preserved rod and cone function and greatly preserved overall photoreceptor numbers.

Topics: Animals; Apoptosis; Cell Count; Cell Nucleus; Cholagogues and Choleretics; Dark Adaptation; Disease Models, Animal; Electroretinography; Female; Fluorescent Antibody Technique, Indirect; In Situ Nick-End Labeling; Male; Mice; Mice, Inbred C57BL; Microscopy, Fluorescence; Photoreceptor Cells, Vertebrate; Retinitis Pigmentosa; Rod Opsins; Taurochenodeoxycholic Acid

Ursodeoxycholic (UDCA) and tauroursodeoxycholic (TUDCA) acids modulate apoptosis and regulate cell-cycle effectors, including cyclin D1. In contrast, deoxycholic acid (DCA) induces cell death and cyclin D1. In this study, we explored the role of cyclin D1 in DCA-induced toxicity and further elucidated the antiapoptotic function of UDCA and TUDCA in primary rat hepatocytes. Cells were incubated with DCA and with or without UDCA or TUDCA for 8-30 h. In addition, hepatocytes were transfected with either an adenovirus expressing cyclin D1 or with a cyclin D1 reporter plasmid with or without bile acids. Finally, cells were cotransfected with short interfering RNA targeting p53. Unlike DCA, both UDCA and TUDCA reduced cyclin D1 expression and transcriptional activation, confirming our previous DNA microarray data. Furthermore, UDCA and TUDCA prevented DCA-induced cyclin D1 and cell death. Cyclin D1 overexpression increased DCA-induced Bax translocation, cytochrome c release, and apoptosis. However, UDCA and TUDCA were less efficient at decreasing cyclin D1 levels as well as DCA-induced changes with overexpression. Finally, after p53 silencing, the effects of cyclin D1 overexpression were almost completely abrogated, whereas UDCA and TUDCA cytoprotective potential was reestablished. In conclusion, cyclin D1 is a relevant player in modulating apoptosis by bile acids, in part through a p53-dependent mechanism.

Topics: Animals; Apoptosis; bcl-2-Associated X Protein; Cyclin D1; Cytochromes c; Deoxycholic Acid; Gene Expression Regulation; Hepatocytes; Male; Protein Transport; Rats; Rats, Sprague-Dawley; Taurochenodeoxycholic Acid; Tumor Suppressor Protein p53; Ursodeoxycholic Acid

Black bear bile has been used in traditional Chinese medicine to treat liver and eye related illnesses for centuries. A major constituent of bile is ursodeoxycholic acid (UDCA). Recent analysis of the cellular effects of UDCA and its taurine conjugate tauroursodeoxycholic acid (TUDCA) have demonstrated their antiapoptotic properties through regulation of Bcl-2 family and survival signaling proteins (Bax, Bad, phosphatidylinositol-3-kinase). In this study, we tested the hypothesis that TUDCA administered to rats prior to a myocardial infarction (MI) would exhibit anti-apoptotic effects and improve cardiac function. Prior to ligation of the left anterior descending (LAD) coronary artery, TUDCA (50 mg/ml, 400 mg/kg, IV) or PBS was administered to rats. Animals were sacrificed 24 hours after ligation for terminal transferase-mediated dUTP-digoxigenin nick end-labeling (TUNEL) and caspase-3 activity to assess apoptosis. Additional TUDCA or PBS treated rats underwent pre-operative,1 and 4 week transthoracic ultrasounds to assess heart function by quantification of shortening fraction (SF) and infarct area. TUNEL labeling of the cardiac tissue revealed a significant reduction in apoptotic cells in rats given TUDCA prior to ischemic injury (p = 0.05). In support of reducing apoptosis, caspase-3 activity in the TUDCA treated animals also decreased (p = 0.02). By 4 weeks, a significantly smaller infarct area was present in the TUDCA group compared to the PBS group (0.05 vs. 0.13 cm(2), p = NS) and there was also an improvement in SF. The results provide evidence for TUDCA as a viable treatment for reducing apoptosis in a model of myocardial infarction. Additional studies will distinguish the functional result of improved cell survival following infarction, suggesting the potential for clinical application of this anti-apoptotic drug in treatment of acute MI.

Topics: Animals; Apoptosis; Caspase 3; Cholagogues and Choleretics; Echocardiography; In Situ Nick-End Labeling; Models, Animal; Myocardial Infarction; Myocardium; Rats; Stroke Volume; Taurochenodeoxycholic Acid

Z alpha-1 antitrypsin (AAT) deficiency is a genetic disease associated with accumulation of misfolded AAT in the endoplasmic reticulum (ER) of hepatocytes. ZAAT-expressing cells display ER stress responses including nuclear factor kappaB activation and apoptosis. Using an in vitro model of ZAAT ER accumulation, we investigated the mechanism of ZAAT-mediated ER-induced apoptosis and evaluated methods to inhibit this process. Here we demonstrate that expression of ZAAT, but not normal MAAT, in HEK293 cells leads to cleavage and activation of caspase-4 and induces apoptosis that is characterized by activation of caspase-3 and caspase-7 and DNA fragmentation. Similar effects are also induced using the ER agonist thapsigargin. A caspase-4-specific short interfering RNA (siRNA) does not impair ZAAT-induced caspase-3/7 activation or cell death in these cells. However, inhibition studies performed using tauroursodeoxycholic acid (TUDCA) demonstrate its ability to inhibit caspase-4 and caspase-3/7 activation, mitochondrial cytochrome c release, and caspase-3 cleavage induced by ZAAT and to promote cell survival. The mechanism by which TUDCA (tauroursodeoxycholic acid) promotes cell survival in ZAAT-expressing cells involves phosphorylation and inactivation of the proapoptotic factor Bad. TUDCA is unable to rescue cells from apoptosis or phosphorylate Bad in the presence of LY294002, a selective P-I-3-kinase inhibitor.. These data show that caspase-4 is not essential for ZAAT-induced apoptosis in HEK293 cells and implicates P-I-3-kinase and Bad as potential therapeutic targets for the liver disease associated with ZAAT deficiency.

Topics: alpha 1-Antitrypsin; Apoptosis; bcl-Associated Death Protein; Caspase 3; Caspases, Initiator; Cells, Cultured; Cytochromes c; Humans; Phosphatidylinositol 3-Kinases; Phosphorylation; Taurochenodeoxycholic Acid

Hereditary Hemochromatosis (HH) is a genetic disease associated with iron overload, in which individuals homozygous for the mutant C282Y HFE associated allele are at risk for the development of a range of disorders particularly liver disease. Conformational diseases are a class of disorders associated with the expression of misfolded protein. HFE C282Y is a mutant protein that does not fold correctly and consequently is retained in the Endoplasmic Reticulum (ER). In this context, we sought to identify ER stress signals associated with mutant C282Y HFE protein expression, which may have a role in the molecular pathogenesis of HH.. Vector constructs of Wild type HFE and Mutant C282Y HFE were made and transfected into HEK293 cell lines. We have shown that expression of C282Y HFE protein triggers both an unfolded protein response (UPR), as revealed by the increased GRP78, ATF6 and CHOP expression, and an ER overload response (EOR), as indicated by NF-kappaB activation. Furthermore, C282Y HFE protein induced apoptotic responses associated with activation of ER stress. Inhibition studies demonstrated that tauroursodeoxycholic acid, an endogenous bile acid, downregulates these events. Finally, we found that the co-existence of both C282Y HFE and Z alpha 1-antitrypsin protein (the protein associated with the liver disease of Z alpha 1-antitrypsin deficiency) expression on ER stress responses acted as potential disease modifiers with respect to each other.. Our novel observations suggest that both the ER overload response (EOR) and the unfolded protein response (UPR) are activated by mutant C282Y HFE protein.

Topics: Activating Transcription Factor 6; alpha 1-Antitrypsin; Apoptosis; Cells, Cultured; Chemokine CCL2; Endoplasmic Reticulum; Endoplasmic Reticulum Chaperone BiP; Gene Expression Regulation; Hemochromatosis Protein; Histocompatibility Antigens Class I; Humans; Interleukin-8; Membrane Proteins; Models, Biological; Polymorphism, Single Nucleotide; Protein Folding; Protein Transport; Signal Transduction; Taurochenodeoxycholic Acid; Transcription Factor CHOP; Transfection

Many cataractogenic stresses also induce endoplasmic reticulum (ER) stress in lens epithelial cells (LECs), which appears to be one of the universal inducers of cell death. In galactosemic rats, activation of ER stress results in the activation of the unfolded protein response (UPR)-dependent death pathway, production of reactive oxygen species (ROS), and cell death. All are induced and precede cataract formation. Cellular osmolytes such as 4-phenylbutyric acid (PBA), trimethylamine N-oxide (TMAO), and tauroursodeoxychoric acid (TUDCA) are known to suppress the induction of ER stress. We investigated whether these small molecules prevent cataract formation in galactose-fed rat lenses.. Cultured LECs were treated with galactose and each cellular osmolyte. Sprague-Dawley rats were fed a 50% galactose chow for 15 days with or without cellular osmolyte treatment. Similarly, selenite was injected subcutaneously into rats with or without cellular osmolytes. Calcein AM and ethidium homodimer-1 (EthD) were used to detect live and dead cells, respectively. The cellular osmolytes, PBA, TMAO, and TUDCA were tested for their ability to suppress LEC death and cataract formation.. Cellular osmolytes rescued cultured human LECs which were treated with the ER stressors. We administered these osmolytes either orally or by injection into galactosemic Sprague-Dawley rats. These rats had significantly reduced LEC death and partially delayed hypermature cataract formation. Since the UPR was not activated in cultured LECs treated with selenite, we used the selenite nuclear cataract as a UPR-independent death pathway control. In selenite-induced nuclear cataract in rats, cellular osmolytes did not prevent LEC death and did not alleviate cataract formation.. These results further establish that ER stress and LEC death play a vital role in certain types of cataract formation. In addition, cellular osmolytes may be potential prophylactic drugs for some types of cataracts.

Topics: Animals; Body Weight; Cataract; Cell Death; Cell Survival; Cells, Cultured; Disease Models, Animal; Endoplasmic Reticulum; Epithelial Cells; Galactose; Galactosemias; Humans; Lens, Crystalline; Methylamines; Phenylbutyrates; Protein Folding; Rats; Rats, Sprague-Dawley; Sodium Selenite; Taurochenodeoxycholic Acid; Tunicamycin; Up-Regulation

Ursodeoxycholic acid exerts anticholestatic effects in chronic cholestatic liver disease in humans as well as in experimental animal models of cholestasis. Its taurine conjugate, TUDCA, was recently shown to stimulate insertion of the apical conjugate export pump, Mrp2 (ABCC2), into canalicular membranes of rat hepatocytes made cholestatic by exposure to taurolithocholic acid (TLCA). The aim of this immunoelectronmicroscopic study was to test whether TLCA and TUDCA modulate the canalicular density of the other key apical transporter, the bile salt export pump, Bsep (ABCB11), in a similar way. Immunoelectronmicroscopic analysis of Bsep density on canalicular membranes, microvilli, and pericanalicular area of hepatocytes was performed in rat liver tissue prepared after liver perfusion with bile acids or carrier medium only. TLCA (10 micromol/l for 50 min) decreased Bsep density in canalicular membranes to 31% of controls (P<0.05) when bile flow was reduced to 35% of controls (P<0.05). Concomitantly, Bsep density in a 1 microm pericanalicular zone increased to 202% (P<0.05) indicating effective retrieval of Bsep from the canalicular membrane induced by TLCA. Coadministration of TUDCA (25 micromol/l) led to a 3.2-fold increase of Bsep density in canalicular membranes equal to control liver (P<0.05 vs TLCA) in association with a 3.8-fold increase of bile flow (P<0.05 vs TLCA). Stimulation of apical membrane insertion of key transporters like the bile salt export pump, Bsep, and-as previously shown-the conjugate export pump, Mrp2, may contribute to the anticholestatic action of UDCA amides in cholestatic conditions.

Topics: Animals; ATP Binding Cassette Transporter, Subfamily B, Member 11; ATP-Binding Cassette Transporters; Bile; Bile Canaliculi; Cholestasis; Liver; Microscopy, Immunoelectron; Multidrug Resistance-Associated Protein 2; Rats; Taurochenodeoxycholic Acid

To further characterise precision-cut liver slices from 34- to 40-day-old male rats as an in vitro model for bile acid (BA) metabolism and transport, the effect of the primary BAs cholic (CA, 5 microM) and chenodeoxycholic acid (CDCA, 0.15 and 0.75 microM) as well as of the therapeutically used tauroursodeoxycholic acid (T-UDCA, 5 microM) on BA profiles was investigated. After 4 h incubation in 5 ml Krebs-Henseleit buffer (KHB) 26 individual BAs were determined in slices (50 mg liver/5 ml KHB) and medium by HPLC with postcolumn derivatisation and fluorescence detection. In control incubations, mean total BA concentrations were 5.09 nmol/50 mg liver (101.80 nmol/g liver) in slices and 25.71 nmol/5 ml KHB, among them 72% taurine-(T-), 22% glycine-(G-) conjugated and 6% free BAs in tissue and medium. The main BAs were beta-muricholic (beta-MCA and conjugates) and cholic acids (CA and conjugates) in tissue and medium. The following results were obtained after addition of CDCA, CA, and T-UDCA, respectively, to the KHB. The toxic CDCA was quantitatively converted mainly to T-UDCA and taurohyodeoxycholic (T-HDCA) acid. CA was conjugated in equal shares to T- and G-CA, whereas T-UDCA was enriched in slices and hydroxylated half to T-beta-MCA, which is the main BA in rats. In conclusion, rat liver slices are highly effective not only in uptake, conjugation and excretion of BAs but also in conversion of strong detergent into less toxic BAs.

Topics: Animals; Biological Transport; Chenodeoxycholic Acid; Cholagogues and Choleretics; Cholic Acid; Dose-Response Relationship, Drug; In Vitro Techniques; Liver; Male; Models, Biological; Rats; Rats, Inbred Strains; Taurochenodeoxycholic Acid

Chronic cholestatic liver diseases are characterized by impaired balance between proliferation and death of cholangiocytes, as well as vanishing of bile ducts and liver failure. Ursodeoxycholic acid (UDCA) is a bile acid widely used for the therapy of cholangiopathies. However, little is known of the cytoprotective effects of UDCA on cholangiocytes. Therefore, UDCA and its taurine conjugate tauroursodeoxycholic acid (TUDCA) were administered in vivo to rats simultaneously subjected to bile duct ligation and vagotomy, a model that induces cholestasis and loss of bile ducts by apoptosis of cholangiocytes. Because these two bile acids act through Ca2+ signaling, animals were also treated with BAPTA/AM (an intracellular Ca2+ chelator) or Gö6976 (a Ca2+-dependent protein kinase C-alpha inhibitor). The administration of UDCA or TUDCA prevented the induction of apoptosis and the loss of proliferative and functional responses observed in the bile duct ligation-vagotomized rats. These effects were neutralized by the simultaneous administration of BAPTA/AM or Gö6976. UDCA and TUDCA enhanced intracellular Ca2+ and IP3 levels, together with increased phosphorylation of protein kinase C-alpha. Parallel changes were observed regarding the activation of the MAPK and PI3K pathways, changes that were abolished by addition of BAPTA/AM or Gö6976. These studies provide information that may improve the response of cholangiopathies to medical therapy.

Topics: Animals; Apoptosis; Bile Ducts; Calcium; Cell Proliferation; Cholestasis; Cytoprotection; Disease Models, Animal; Egtazic Acid; Enzyme Activation; Epithelium; Ligation; Male; Mitogen-Activated Protein Kinase Kinases; Phosphatidylinositol 3-Kinases; Phosphorylation; Protein Kinase C-alpha; Rats; Rats, Inbred F344; Signal Transduction; Taurochenodeoxycholic Acid; Ursodeoxycholic Acid; Vagotomy

Hepatocyte growth factor (HGF) accelerates tissue regeneration and ameliorates tissue fibrosis through its ligand c-Met receptor tyrosine kinase. Hence, HGF is currently discussed as an attractive therapeutic candidate for fatal liver diseases. However, it remains unclear whether c-Met of de-differentiated hepatocytes adequately responds to HGF in an impaired liver. Therefore, we investigated c-Met expression and c-Met responsiveness to HGF in an experimental de-differentiation cell culture system. Primary rat hepatocytes were seeded on a two-dimensional collagen matrix or embedded within a three dimensional collagen gel to guarantee intact cell geometry. Cells were cultivated in a growth factor enriched extracellular milieu (de-differentiation medium), or in a chemically defined differentiation medium, representing physiologically intact hepatocytes. c-Met surface expression was determined by flow cytometry. Receptor localisation was examined by confocal microscopy, c-Met and phosphorylated c-Met protein were determined by western blotting. Hepatocyte-specific asialoglycoprotein receptor (ASGPr) was examined to control the differentiation status of the cells. Growth factor enriched milieu induced a rapid loss of ASGPr with a significant increase of c-Met surface level and a decrease in c-Met protein level. Surprisingly, the increased amount of c-Met surface expression was associated with its loss of responsiveness to HGF. The addition of bile acids into the culture medium had significantly delayed the process of de-differentiation and restrained the drastic elevation of c-Met (tauroursodeoxycholic acid > ursodeoxycholic acid). Application of the three-dimensional hepatocellular architecture stabilized the c-Met surface receptor level and rendered c-Met activation. We have demonstrated that growth factor enriched extracellular milieu and loss of intact liver architecture seems to be accompanied by an up-regulation of c-Met surface level. Our findings suggest that irresponsiveness of c-Met to soluble HGF was possibly caused by an excessive HGF production and receptor over-stimulation. Both events should be considered when establishing an HGF-based therapy for fibrosis/cirrhosis.

Topics: Animals; Asialoglycoprotein Receptor; Cell Differentiation; Cell Shape; Cells, Cultured; Collagen; Culture Media, Serum-Free; Dose-Response Relationship, Drug; Hepatocyte Growth Factor; Hepatocytes; Liver Cirrhosis, Experimental; Male; Models, Biological; Proto-Oncogene Proteins c-met; Rats; Rats, Sprague-Dawley; Taurochenodeoxycholic Acid; Up-Regulation; Ursodeoxycholic Acid

Ethinylestradiol (EE) induces intrahepatic cholestasis in experimental animals being its derivative, ethinylestradiol 17beta-glucuronide, a presumed mediator of this effect. To test whether glucuronidation is a relevant step in the pathogenesis of cholestasis induced by EE (5 mg/kg b.wt. s.c. for 5 consecutive days), the effect of simultaneous administration of galactosamine (200 mg/kg b.wt. i.p.) on biliary secretory function was studied. A single injection of this same dose of galactosamine was able to decrease hepatic UDP-glucuronic acid (UDP-GA) levels by 85% and excretion of EE-17beta-glucuronide after administration of a tracer dose of [3H]EE by 40%. Uridine (0.9 g/kg b.wt. i.p.) coadministration reverted the effect of galactosamine on hepatic UDP-GA levels and restored the excretion of [3H]EE-17beta-glucuronide. When administered for 5 days, galactosamine itself did not alter any of the serum markers of liver injury studied (aspartate aminotransferase, alanine aminotransferase, and alkaline phosphatase) or biliary secretory function. When coadministered with EE, galactosamine partially prevented the impairment induced by this estrogen in total bile flow, the bile-salt-independent fraction of bile flow, basal bile salt secretion, and the secretory rate maximum of tauroursodeoxycholate. Uridine coadministration partially prevented galactosamine from exerting its anticholestatic effects. In conclusion, galactosamine administration partially prevented EE-induced cholestasis by a mechanism involving decreased UDP-GA availability for subsequent formation of EE 17beta-glucuronide. The evidence thus supports the hypothesis that EE 17beta-glucuronide is involved in the pathogenesis of EE cholestasis.

Topics: Animals; Bile; Cholestasis; Ethinyl Estradiol; Galactosamine; Liver; Male; Rats; Rats, Wistar; Taurochenodeoxycholic Acid; Uridine; Uridine Diphosphate Glucuronic Acid

Tauroursodeoxycholic acid (TUDCA) prevents amyloid beta-peptide (Abeta)-induced neuronal apoptosis, by modulating both classical mitochondrial pathways and specific upstream targets. In addition, activation of nuclear steroid receptors (NSRs), such as the mineralocorticoid receptor (MR) and the glucocorticoid receptor (GR) differentially regulates apoptosis in the brain. In this study we investigated whether TUDCA, a cholesterol-derived endogenous molecule, requires NSRs for inhibiting Abeta-induced apoptosis in primary neurons. Our results confirmed that TUDCA significantly reduced Abeta-induced apoptosis; in addition, the fluorescently labeled bile acid molecule was detected diffusely in both cytoplasm and nucleus of rat cortical neurons. Interestingly, experiments using small interfering RNAs (siRNAs) revealed that, in contrast to GR siRNA, MR siRNA abolished the antiapoptotic effect of TUDCA. Abeta incubation reduced MR nuclear translocation while increasing nuclear GR levels. Notably, pretreatment with TUDCA markedly altered Abeta-induced changes in NSRs, including MR dissociation from its cytosolic chaperone, heat shock protein 90, and subsequent translocation to the nucleus. Furthermore, when a carboxy terminus-deleted form of MR was used, nuclear trafficking of both MR and the bile acid was abrogated, suggesting that they translocate to the nucleus as a steroid-receptor complex. Transfection experiments with wild-type or mutant MR confirmed that this interaction was required for TUDCA protection against Abeta-induced apoptosis. Finally, in cotransfection experiments with NSR response element reporter and overexpression constructs, pretreatment with TUDCA significantly modulated Abeta-induced changes in MR and GR transactivation. In conclusion, these results provide novel insights into the specific cellular mechanism of TUDCA antiapoptotic function against Abeta-induced apoptosis and suggest targets for potential therapeutic intervention.

Topics: Amyloid beta-Peptides; Animals; Apoptosis; Cell Nucleus; Cells, Cultured; Immunoblotting; Immunoprecipitation; Microscopy, Fluorescence; Neurons; Rats; Receptors, Glucocorticoid; Receptors, Mineralocorticoid; RNA, Small Interfering; Taurochenodeoxycholic Acid; Transcriptional Activation

The main player in biliary cholesterol secretion is the heterodimeric transporter complex, ABCG5/ABCG8, the function of which is necessary for the majority of sterols secreted into bile. It is not clear whether the primary step in this process is flopping of cholesterol from the inner to the outer leaflet of the canalicular membrane, with desorption by mixed micelles, or decreasing of the activation energy required for cholesterol desorption from the outer membrane leaflet. In this study, we investigated these mechanisms by infusing Abcg8(+/+), Abcg8(+/-), and Abcg8(-/-) mice with hydrophilic and hydrophobic bile salts. In Abcg8(-/-) mice, this failed to substantially stimulate biliary cholesterol secretion. Infusion of the hydrophobic bile salt taurodeoxycholate also resulted in cholestasis, which was induced in Abcg8(-/-) mice at a much lower infusion rate compared with Abc8(-/-) and Abcg8(+/-) mice, suggesting a reduced cholesterol content in the outer leaflet of the canalicular membrane. Indeed, isolation of canalicular membranes revealed a reduction of 45% in cholesterol content under these conditions in Abcg8(-/-) mice. Our data support the model that ABCG5/ABCG8 primarily play a role in flopping cholesterol (and sterols) from the inner leaflet to the outer leaflet of the canalicular membrane.

Topics: Animals; ATP Binding Cassette Transporter, Subfamily G, Member 5; ATP Binding Cassette Transporter, Subfamily G, Member 8; ATP-Binding Cassette Transporters; Bile; Bile Acids and Salts; Biological Transport; Cholesterol; Diosgenin; Lipoproteins; Liver; Mice; Mice, Inbred C57BL; Taurochenodeoxycholic Acid; Taurocholic Acid; Taurodeoxycholic Acid

Ursodeoxycholic acid (UDCA) and its taurine-conjugate, tauroursodeoxycholic acid (TUDCA), play a unique role in modulating the apoptotic threshold in cells. The mechanism is thought to involve, in part, inhibition of translocation for Bax from the cytosol to mitochondria. Here, we attempted to use the native fluorescence of the tryptophan residues of Bax to determine whether bile acids bind directly to recombinant Bax protein. The results showed that UDCA had no effect on the tryptophan fluorescence of Bax. Similarly, there was no evidence of direct binding between Bax protein and the more hydrophobic bile acid, deoxycholic acid (DCA). In contrast, the fluorescence change detected for Bax solution titrated against TUDCA in dimethylsulfoxide was greater than that observed with solvent alone. In conclusion, data from fluorescence spectroscopy does not support a direct interaction of UDCA or DCA with Bax protein, whereas it suggests that there may be some potential interaction with TUDCA.

Topics: bcl-2-Associated X Protein; Cholagogues and Choleretics; Fluorescence; Humans; Protein Binding; Recombinant Proteins; Taurochenodeoxycholic Acid; Tryptophan; Ursodeoxycholic Acid

Early onset familial Alzheimer's disease (FAD) is linked to autosomal dominant mutations in the amyloid precursor protein (APP) and presenilin 1 and 2 (PS1 and PS2) genes. These are critical mediators of total amyloid beta-peptide (Abeta) production, inducing cell death through uncertain mechanisms. Tauroursodeoxycholic acid (TUDCA) modulates exogenous Abeta-induced apoptosis by interfering with E2F-1/p53/Bax. Here, we used mouse neuroblastoma cells that express either wild-type APP, APP with the Swedish mutation (APPswe), or double-mutated human APP and PS1 (APPswe/DeltaE9), all exhibiting increased Abeta production and aggregation. Cell viability was decreased in APPswe and APPswe/DeltaE9 but was partially reversed by z-VAD.fmk. Nuclear fragmentation and caspase 2, 6 and 8 activation were also readily detected. TUDCA reduced nuclear fragmentation as well as caspase 2 and 6, but not caspase 8 activities. p53 activity, and Bcl-2 and Bax changes, were also modulated by TUDCA. Overexpression of p53, but not mutant p53, in wild-type and mutant neuroblastoma cells was sufficient to induce apoptosis, which, in turn, was reduced by TUDCA. In addition, inhibition of the phosphatidylinositide 3'-OH kinase pathway reduced TUDCA protection against p53-induced apoptosis. In conclusion, FAD mutations are associated with the activation of classical apoptotic pathways. TUDCA reduces p53-induced apoptosis and modulates expression of Bcl-2 family.

Topics: Alzheimer Disease; Amino Acid Chloromethyl Ketones; Amyloid beta-Protein Precursor; Animals; Antiviral Agents; Apoptosis; bcl-2-Associated X Protein; Blotting, Western; Caspases; Cell Line, Tumor; Cysteine Proteinase Inhibitors; Enzyme Activation; Humans; In Situ Nick-End Labeling; Membrane Proteins; Mice; Mutation; Neuroblastoma; Presenilin-1; Presenilin-2; Proto-Oncogene Proteins c-bcl-2; Taurochenodeoxycholic Acid; Transfection; Tumor Suppressor Protein p53

Endoplasmic reticulum (ER) stress is a key link between obesity, insulin resistance, and type 2 diabetes. Here, we provide evidence that this mechanistic link can be exploited for therapeutic purposes with orally active chemical chaperones. 4-Phenyl butyric acid and taurine-conjugated ursodeoxycholic acid alleviated ER stress in cells and whole animals. Treatment of obese and diabetic mice with these compounds resulted in normalization of hyperglycemia, restoration of systemic insulin sensitivity, resolution of fatty liver disease, and enhancement of insulin action in liver, muscle, and adipose tissues. Our results demonstrate that chemical chaperones enhance the adaptive capacity of the ER and act as potent antidiabetic modalities with potential application in the treatment of type 2 diabetes.

Topics: Adipose Tissue; Animals; Blood Glucose; Cell Line, Tumor; Diabetes Mellitus, Type 2; Disease Models, Animal; eIF-2 Kinase; Endoplasmic Reticulum; Enzyme Activation; Eukaryotic Initiation Factor-2; Glucose; Glucose Tolerance Test; Homeostasis; Insulin; Insulin Resistance; JNK Mitogen-Activated Protein Kinases; Liver; Mice; Mice, Obese; Phenylbutyrates; Phosphorylation; Receptor, Insulin; Signal Transduction; Taurochenodeoxycholic Acid

Bear bile has been used in Asia for over 3,000 years to treat visual disorders, yet its therapeutic potential remains unexplored in Western vision research. The purpose of this study was to test whether treatment of mice undergoing retinal degeneration with tauroursodeoxycholic acid (TUDCA), a primary constituent of bear bile, alters the course of degeneration.. Two retinal degeneration models were tested: the rd10 mouse, which has a point mutation in the gene encoding the beta subunit of rod phosphodiesterase, and light induced retinal damage (LIRD). For LIRD studies, albino Balb/C adult mice were subcutaneously injected with TUDCA (500 mg/kg body weight) or vehicle (0.15 M NaHCO(3)). Sixteen h later, each mouse received repeat injections. Half of each treatment group was then placed in bright light (10,000 lux) or dim light (200 lux) for seven h. At the end of exposure, animals were transferred to their regular housing. Electroretinograms (ERGs) were assessed 24 h later, mice sacrificed, eyes embedded in paraffin and sectioned, and retina sections assayed for morphology and apoptosis by TUNEL and anti-active caspase-3 immunoreactivity via fluorescent confocal microscopy. A subset of mice were sacrificed 8 and 15 days after exposure and retina sections analyzed for morphology and apoptosis. For rd10 studies, mice were injected subcutaneously with TUDCA or vehicle at postnatal (P) days 6, 9, 12, and 15. At p18, ERGs were recorded, mice were euthanized and eyes were harvested, fixed, and processed. Retinal sections were stained (toluidine blue), and retinal cell layers morphometrically analyzed by light microscopy. Consecutive sections were analyzed for apopotosis as above.. By every measure, TUDCA greatly slowed retinal degeneration in LIRD and rd10 mice. ERG a-wave and b-wave amplitudes were greater in mice treated with TUDCA compared to those treated with vehicle. Retinas of TUDCA-treated mice had thicker outer nuclear layers, more photoreceptor cells, and more fully-developed photoreceptor outer segments. Finally, TUDCA treatments dramatically suppressed signs of apoptosis in both models.. Systemic injection of TUDCA, a primary constituent of bear bile, profoundly suppressed apoptosis and preserved function and morphology of photoreceptor cells in two disparate mouse models of retinal degeneration. It may be that bear bile has endured so long in Asian pharmacopeias due to efficacy resulting from this anti-apoptotic and neuroprotective activity of TUDCA. These results also indicate that a systematic, clinical assessment of TUDCA may be warranted.

Topics: Animals; Apoptosis; Bile; Blindness; Cyclic Nucleotide Phosphodiesterases, Type 6; Disease Models, Animal; Electroretinography; Injections, Subcutaneous; Light; Medicine, East Asian Traditional; Mice; Mice, Mutant Strains; Phosphoric Diester Hydrolases; Photoreceptor Cells, Vertebrate; Retinal Degeneration; Taurochenodeoxycholic Acid; Ursidae

To determine whether Tauroursodeoxycholic acid (TUDCA) can penetrate the blood-ocular barrier after orally administration of Fel Ursi.. 56 rabbits were divided into two groups, 48 rabbits were used in experimental group, and other 8 rabbits were served as control. 100 mg/ml Fel Ursi were a fused into rabbits stomach. 2 ml blood from vein of auris-edge, aqueous humor from left eye and vitreous sample from right eye were obtained at 0.5, 1.0, 2.0, 4.0, 6.0 and 8.0 h after Fel Ursi administration. Concentration of TUDCA from all of samples was determined by HPLC.. TUDCA Concentrations were (999.1 +/- 17.2) - (1300.6 +/- 78.2) microg/ml, (12.7 +/- 1.4) - (47.8 +/- 4.7) microg/ml, and (10.8 +/- 2.9) - (57.9 +/- 7.9) microg/ml in blood, aqueous humor and vitreous respectively. There was no significant differences in the concentration of TUDCA in samples of aqueous humor and vitreous (P > 0.05). However the concentration of TUDCA in rabbit blood was much higher compared with that in aqueous humor and vitreous (P < 0.01).. Fel Ursi can reach intraocular tissue through penetrating blood-aqueous barrier and blood-vitreous barrier after orally application.

Topics: Animals; Blood-Aqueous Barrier; Drugs, Chinese Herbal; Eye; Permeability; Rabbits; Taurochenodeoxycholic Acid

Topics: Animals; Cell Communication; Cholestasis; Gap Junctions; Liver; Mice; Taurochenodeoxycholic Acid

Olmesartan (RNH-6270) is a newly developed anigotensin II receptor antagonist, and has been reported to be excreted into feces. To examine the mechanism of the biliary excretion of olmesartan, we studied its biliary excretion in rats.. The biliary excretion of olmesartan in Eisai hyperbilirubinemic rats (EHBR), a multidrug resistance protein 2-deficient rat, was compared with control rats, and the effect of organic anions and cation and bile acids on the biliary excretion of olmesartan was studied in control rats.. The biliary excretion of olmesartan was markedly delayed in EHBR. The biliary excretion of olmesartan was inhibited by sulfobromophthalein, cefpiramide and pravastatin, but was not inhibited by taurocholate or tauroursodeoxycholate. Vinblastine inhibited and phenothiazine treatment increased the biliary excretion of olmesartan.. These findings suggest that olmesartan is excreted into the bile mainly by multidrug resistance protein 2 and partly by P-glycoprotein.

Topics: Angiotensin II Type 1 Receptor Blockers; Animals; ATP-Binding Cassette Transporters; Cephalosporins; Common Bile Duct; Imidazoles; Male; Olmesartan Medoxomil; Phenothiazines; Pravastatin; Rats; Rats, Mutant Strains; Rats, Sprague-Dawley; Sulfobromophthalein; Taurochenodeoxycholic Acid; Taurocholic Acid; Tetrazoles; Vinblastine

Tauroursodeoxycholic acid (TUDCA) is a cytoprotective bile acid frequently prescribed to patients with cholestatic diseases. Several mechanisms of action have been investigated, but the possibility that cyclic adenosine monophosphate responsive element binding protein (CREB), a transcription factor promoting cell survival, mediates TUDCA's protective effects has not been considered. We examined whether TUDCA activates CREB and whether this activation can protect biliary epithelial cells. Cholangiocytes were stressed by exposure to CCI-779, which inhibits signaling though the kinase mTOR (mammalian target of rapamycin), resulting in cell cycle arrest and apoptosis. Incubation of normal rat cholangiocytes (NRC) cells, with TUDCA resulted in phosphorylation of CREB (Western blotting analysis) and activation of CREB transcription activity (luciferase reporter assay). Inhibition of calcium signals and inhibition of protein kinase C prevented the TUDCA-induced activation of CREB. CCI-779 decreased the viability of rat cholangiocytes in a dose-dependent manner (MTT [3-(4,5-dimethythiazol-2-yl)-2,5-diphenyl tetrazolium bromide] assay). TUDCA protected against CCI-779 cytotoxicity. A dominant negative form of CREB was stably transduced in NRC cells (NRC-M1). TUDCA protection was decreased in NRC-M1. While CCI-779 induced apoptosis in NRC cells as determined by caspase 3 activity, TUDCA attenuated CCI-779-induced apoptosis, an effect absent in NRC-M1. Finally, CCI-779 blocked proliferation of both NRC and NRC-M1 (thymidine incorporation) and this was unaffected by TUDCA. In conclusion, TUDCA activates CREB in cholangiocytes, reducing the apoptotic effect of CCI-779. These findings suggest a novel cytoprotective mechanism for this bile acid.

Topics: Animals; Apoptosis; Bile Ducts; Blotting, Western; Cell Line, Tumor; Cell Proliferation; Cell Survival; Cyclic AMP Response Element-Binding Protein; Cytoprotection; Phosphorylation; Protein Kinases; Rats; Sirolimus; Taurochenodeoxycholic Acid; TOR Serine-Threonine Kinases; Transcription, Genetic

The mechanism of interferon (IFN)-alpha-induced depression remains poorly understood. Recently, modulation of glucocorticoid receptor (GR) and serotonin receptor 1A (5-HTR1A) were implicated in mechanism(s) leading to depression. To gain insight into this mechanism, we assessed the effect of IFN-alpha on the modulation of GR and 5-HTR1A expression.. Hepatoblastoma, myelocyte-derived and T cell leukemia-derived cell lines were treated with titrated doses of IFN-alpha for different incubation times and analyzed by Western blot, RT-PCR, and microarrays. Dose- and time-dependent decreases of proteins and mRNA levels of GR and 5-HTR1A were observed.. The expression of GR and 5-HTR1A in cells treated for 6 days decreased by 74 and 72%, respectively. Recovery was observed following IFN-alpha withdrawal. Co-incubation with tricyclic antidepressants (desipramine) or serotonin reuptake inhibitors (fluoxetine) attenuated the effect of IFN-alpha on GR or 5-HTR1A. GR and 5-HTR1A were unaffected by treatment with either IFN-gamma or tauroursodeoxycholic acid (TUDCA). However, the effect of IFN-alpha on GR was abolished when used in combination with TUDCA.. In conclusion, IFN-alpha downregulated GR and 5-HTR1A levels in cell lines. These levels of GR and 5-HTR1A, following IFN-alpha-induced downregulation, recovered after withdrawal of IFN-alpha or addition of desipramine or fluoxetine. These data provide insights regarding pathogenesis of IFN-alpha-induced depression.

Topics: Antidepressive Agents, Second-Generation; Antidepressive Agents, Tricyclic; Antiviral Agents; Cell Cycle; Depressive Disorder, Major; Desipramine; Down-Regulation; Fluoxetine; Gene Expression; Hepatoblastoma; Humans; Interferon-alpha; Jurkat Cells; Liver Neoplasms; Oligonucleotide Array Sequence Analysis; Receptor, Serotonin, 5-HT1A; Receptors, Glucocorticoid; Taurochenodeoxycholic Acid

Ursodeoxycholic acid (UDCA) and its taurine-conjugated derivative, TUDCA, modulate cell death and cell cycle regulators, such as E2F-1 and p53. However, precise pathways underlying UDCA's effects are not fully understood. The aim of this study was to identify specific cellular targets of UDCA.. The expression profile of primary rat hepatocytes incubated with UDCA was determined using Affymetrix GeneChip Rat 230A arrays. Hybridization data were processed to identify genes with significant expression changes. RT-PCR and immunoblot analyses of a selected target confirmed microarray data.. The results showed that >440 genes were modulated with UDCA by >1.5-fold; approximately 25% were significantly different from controls. Genes affected by UDCA included new regulatory molecules, such as Apaf-1. RT-PCR and immunoblotting confirmed a decrease in Apaf-1. Other altered genes were directly involved in cell cycle (cyclin D1, cadherin 1, HMG-box containing protein 1) and apoptosis (prothymosin-alpha) events. The E2F-1/p53/Apaf-1 pathway appears to be targeted by UDCA. Finally, transcripts for proteins with kinase activity and transcription factors were specifically modulated by TUDCA.. This study expands our knowledge of the biological effects of UDCA in hepatocytes. Most of the identified genes represent novel potential targets of UDCA, which may ultimately explain its therapeutic properties.

Topics: Animals; Cells, Cultured; Cholagogues and Choleretics; Gene Expression; Hepatocytes; Male; Oligonucleotide Array Sequence Analysis; Rats; Rats, Sprague-Dawley; Taurochenodeoxycholic Acid; Ursodeoxycholic Acid

Hydrophobic bile acids accumulate in the liver during cholestasis and are believed to cause hepatocellular necrosis and apoptosis in part through induction of the mitochondrial permeability transition (MPT) and the mitochondrial generation of oxidative stress. The purpose of this study was to determine if human hepatic mitochondria respond to bile acids in this manner.. The MPT was measured spectrophotometrically and morphologically in normal human liver mitochondria exposed to glycochenodeoxycholic acid (GCDC) with and without cyclosporin A, an inhibitor of the MPT, antioxidants, and tauroursodeoxycholic acid (TUDC). Hydroperoxide generation was measured by dichlorofluorescein fluorescence. Cytochrome c and apoptosis-inducing factor were assessed by immunoblotting.. GCDC induced the MPT in a dose-dependent manner, which was inhibited by cyclosporin A, alpha-tocopherol, beta-carotene, idebenone, and TUDC. GCDC stimulated reactive oxygen species generation and release of cytochrome c and apoptosis-inducing factor, which were significantly inhibited by the antioxidants, cyclosporin A, and TUDC.. Mitochondrial pathways of cell death are stimulated in human hepatic mitochondria exposed to GCDC consistent with the role of mitochondrial dysfunction in the pathogenesis of cholestatic liver injury. These results parallel those reported in rodents, supporting the extrapolation of mechanistic studies of bile acid toxicity from rodent to humans.

Topics: Antioxidants; Apoptosis; Bile Acids and Salts; Cyclosporine; Cytochromes c; Dose-Response Relationship, Drug; Glycochenodeoxycholic Acid; Hepatocytes; Humans; Hydrogen Peroxide; Ion Channels; Mitochondria, Liver; Mitochondrial Membrane Transport Proteins; Mitochondrial Permeability Transition Pore; Reactive Oxygen Species; Spectrophotometry; Taurochenodeoxycholic Acid

How genetic and environmental factors interact in Parkinson disease is poorly understood. We have now compared the patterns of vulnerability and rescue of Caenorhabditis elegans with genetic modifications of three different genetic factors implicated in Parkinson disease (PD). We observed that expressing alpha-synuclein, deleting parkin (K08E3.7), or knocking down DJ-1 (B0432.2) or parkin produces similar patterns of pharmacological vulnerability and rescue. C. elegans lines with these genetic changes were more vulnerable than nontransgenic nematodes to mitochondrial complex I inhibitors, including rotenone, fenperoximate, pyridaben, or stigmatellin. In contrast, the genetic manipulations did not increase sensitivity to paraquat, sodium azide, divalent metal ions (Fe(II) or Cu(II)), or etoposide compared with the nontransgenic nematodes. Each of the PD-related lines was also partially rescued by the antioxidant probucol, the mitochondrial complex II activator, D-beta-hydroxybutyrate, or the anti-apoptotic bile acid tauroursodeoxycholic acid. Complete protection in all lines was achieved by combining d-beta-hydroxybutyrate with tauroursodeoxycholic acid but not with probucol. These results show that diverse PD-related genetic modifications disrupt the mitochondrial function in C. elegans, and they raise the possibility that mitochondrial disruption is a pathway shared in common by many types of familial PD.

Topics: 3-Hydroxybutyric Acid; alpha-Synuclein; Amino Acid Sequence; Animals; Animals, Genetically Modified; Antioxidants; Apoptosis; Benzoates; Benzothiazoles; Bile Acids and Salts; Caenorhabditis elegans; Cholagogues and Choleretics; Copper; Disease Models, Animal; Electron Transport Complex I; Gene Deletion; Gene Expression Regulation; Gene Library; Genetic Techniques; Humans; Immunoblotting; Intracellular Signaling Peptides and Proteins; Ions; Iron; Mitochondria; Molecular Sequence Data; Mutagenesis; Mutation; Neurons; Oncogene Proteins; Oxygen Consumption; Paraquat; Parkinson Disease; Polyenes; Probucol; Protein Deglycase DJ-1; Pyrazoles; Pyridazines; RNA, Small Interfering; Rotenone; Sequence Homology, Amino Acid; Sodium Azide; Taurochenodeoxycholic Acid; Thiazoles; Time Factors; Transgenes; Ubiquitin-Protein Ligases

Tauroursodeoxychate (TUDCA) is used for the treatment of cholangiopathies including primary sclerosing cholangitis, which is considered the primary risk factor for cholangiocarcinoma. The effect of TUDCA on cholangiocarcinoma growth is unknown. We evaluated the role of TUDCA in the regulation of growth of the cholangiocarcinoma cell line Mz-ChA-1. TUDCA inhibited the growth of Mz-ChA-1 cells in concentration- and time-dependent manners. TUDCA inhibition of cholangiocarcinoma growth was blocked by BAPTA-AM, an intracellular Ca(2+) concentration ([Ca(2+)](i)) chelator, and H7, a PKC-alpha inhibitor. TUDCA increased [Ca(2+)](i) and membrane translocation of the Ca(2+)-dependent PKC-alpha in Mz-ChA-1 cells. TUDCA inhibited the activity of MAPK, and this inhibitory effect of TUDCA was abrogated by BAPTA-AM and H7. TUDCA did not alter the activity of Raf-1 and B-Raf and the phosphorylation of MAPK p38 and JNK/stress-activated protein kinase. TUDCA inhibits Mz-ChA-1 growth through a signal-transduction pathway involving MAPK p42/44 and PKC-alpha but independent from Raf proteins and MAPK p38 and JNK/stress-activated protein kinases. TUDCA may be important for the treatment of cholangiocarcinoma.

Topics: Bile Duct Neoplasms; Bile Ducts, Intrahepatic; Biological Transport; Calcium; Cell Line, Tumor; Cholangiocarcinoma; Humans; Intracellular Membranes; Mitogen-Activated Protein Kinases; Osmolar Concentration; Phosphorylation; Protein Kinase C; Protein Kinase C-alpha; Proto-Oncogene Proteins B-raf; Proto-Oncogene Proteins c-raf; Taurochenodeoxycholic Acid; Time Factors

In hepatocytes ethanol (EtOH) is metabolized to acetaldehyde and to acetate. Ursodeoxycholic acid (UDCA) and tauroursodeoxycholic acid (TUDCA) are said to protect the liver against alcohol. We investigated the influence of ethanol and acetaldehyde on alcohol dehydrogenase (ADH)-containing human hepatoma cells (SK-Hep-1) and the protective effects of UDCA and TUDCA (0.01 and 0.1 mM). Cells were incubated with 100 and 200 mM ethanol, concentrations in a heavy drinker, or acetaldehyde. Treatment with acetaldehyde or ethanol resulted in a decrease of metabolic activity and viability of hepatocytes and an increase of cell membrane permeability. During simultaneous incubation with bile acids, the metabolic activity was better preserved by UDCA than by TUDCA. Due to its more polar character, acetaldehyde mostly damaged the superficial, more polar domain of the membrane. TUDCA reduced this effect, UDCA was less effective. Damage caused by ethanol was smaller and predominantly at the more apolar site of the cell membrane. In contrast, preincubation with TUDCA or UDCA strongly decreased metabolic activity and cell viability and led to an appreciable increase of membrane permeability. TUDCA and UDCA only in rather high concentrations reduce ethanol and acetaldehyde-induced toxicity in a different way, when incubated simultaneously with hepatocytes. In contrast, preincubation with bile acids intensified cell damage. Therefore, the protective effect of UDCA or TUDCA in alcohol- or acetaldehyde-treated SK-Hep-1 cells remains dubious.

Topics: Acetaldehyde; Alcohol Dehydrogenase; Cell Line, Tumor; Cell Membrane; Dose-Response Relationship, Drug; Electron Spin Resonance Spectroscopy; Ethanol; Glutathione; Hepatocytes; Humans; L-Lactate Dehydrogenase; Taurochenodeoxycholic Acid; Ursodeoxycholic Acid

The goal of this investigation was to determine whether chenodeoxycholic acid (CDCA)-induced apoptosis is prevented by ursodeoxycholic acid (UDCA) or tauroursodeoxycholic acid (TUDC) and to characterize the involvement of mitochondria in the process. Cultured human HepG2 cells were treated in a dose- and time-dependent protocol in order to establish a sufficiently low exposure to CDCA that causes apoptosis but not necrosis. Low-dose CDCA induced an S-phase block and G2 arrest of the cell cycle, as determined by flow cytometry. As a result, cell proliferation was inhibited. CDCA-induced apoptosis, as determined by fluorescence microscopy of Hoechst 33342-stained nuclei, was evident upon coincubation with TUDC. Additionally, after exposure to UDCA plus CDCA, the cell membrane was permeable to fluorescent dyes. Caspase-9-like activity, poly(ADP-ribose) polymerase (PARP) cleavage, and extensive DNA fragmentation were detected in CDCA-exposed cells and in cells coincubated with TUDC, but not UDCA. CDCA caused a decrease in mitochondrial membrane potential and depletion of ATP, both of which were potentiated by UDCA but not TUDC. The results suggest that UDCA potentiates CDCA cytotoxicity, probably at the level of induction of the mitochondrial permeability transition (MPT). Consequently, as suggested by the lack of the main hallmarks of the apoptotic pathway, in the presence of UDCA, CDCA-induced apoptosis is not properly executed but degenerates into necrosis.

Topics: Adenosine Triphosphate; Apoptosis; Bile Acids and Salts; Bromodeoxyuridine; Caspase 9; Caspases; Cell Cycle; Cell Division; Cell Line; Cell Membrane Permeability; Cell Survival; Chenodeoxycholic Acid; Chromatin; Cytochromes c; DNA; DNA Fragmentation; Dose-Response Relationship, Drug; Drug Synergism; Humans; Mitochondrial Diseases; Necrosis; Poly(ADP-ribose) Polymerases; Taurochenodeoxycholic Acid; Time Factors; Tubulin; Ursodeoxycholic Acid

Deoxycholic acid (DCA) has been appeared to be an endogenous colon tumor promoter. In this study, we investigated whether DCA induces nuclear factor-kappa B (NF-kappa B) activation and IL-8 expression, and tauroursodeoxycholic acid (TUDC) inhibits this signaling in HT-29 cells.. After DCA treatments, time courses of NF-kappa B binding activity were determined by electrophoretic mobility shift assay (EMSA). Also, we performed Western blotting of I kappa B alpha to confirm NF-kappa B activation. Time and concentration courses of DCA-induced secretion of IL-8 were measured with ELISA in supernatants of cultured media from the cells. To evaluate the role of NF-kappa B, IL-8 levels were assessed after pretreatment with using phosphorothioate-modified anti-sense oligonucleotides (ODN). Moreover, DCA-induced secretions of IL-8 were measured after pretreatment with TUDC.. DCA dose-dependently induced prominent NF-kappa B binding complexes from 30 min to 8 hr and degradation of I kappa B alpha. The secretions of IL-8 were increased with DCA (50-200 micro M) treatment in a time and dose-dependent manner. Pre-incubation of the cells with TUDC (0.1-10 micro M) for 2 hours caused significant decreases in DCA induced IL-8 secretion. However, transient transfection using p50 or p65 AS-ODN showed no effect on IL-8 secretion.. DCA may play as a colonic tumor promoter through anti-apoptotic effect of NF-kappa B activation and IL-8 expression, and DCA-induced NF-kappa B independent IL-8 expression is inhibited by TUDC.

Topics: Blotting, Western; Colonic Neoplasms; Deoxycholic Acid; Dose-Response Relationship, Drug; Electrophoretic Mobility Shift Assay; HT29 Cells; Humans; Interleukin-8; NF-kappa B; Oligonucleotides, Antisense; Signal Transduction; Taurochenodeoxycholic Acid; Transcriptional Activation

Ursodeoxycholic acid (UDCA) is used in the treatment of cholestatic liver diseases, but its mechanism of action is not yet well defined. The aim of this study was to explore the protective mechanisms of the taurine-conjugate of UDCA (tauroursodeoxycholic acid [TUDCA]) against glycochenodeoxycholic acid (GCDCA)-induced apoptosis in primary cultures of rat hepatocytes. Hepatocytes were exposed to GCDCA, TUDCA, the glyco-conjugate of UDCA (GUDCA), and TCDCA. The phosphatidylinositol-3 kinase pathway (PI3K) and nuclear factor-kappaB were inhibited using LY 294002 and adenoviral overexpression of dominant-negative IkappaB, respectively. The role of p38 and extracellular signal-regulated protein kinase mitogen-activated protein kinase (MAPK) pathways were investigated using the inhibitors SB 203580 and U0 126 and Western blot analysis. Transcription was blocked by actinomycin-D. Apoptosis was determined by measuring caspase-3, -9, and -8 activity using fluorimetric enzyme detection, Western blot analysis, immunocytochemistry, and nuclear morphological analysis. Our results demonstrated that uptake of GCDCA is needed for apoptosis induction. TUDCA, but not TCDCA and GUDCA, rapidly inhibited, but did not delay, apoptosis at all time points tested. However, the protective effect of TUDCA was independent of its inhibition of caspase-8. Up to 6 hours of preincubation with TUDCA before addition of GCDCA clearly decreased GCDCA-induced apoptosis. At up to 1.5 hours after exposure with GCDCA, the addition of TUDCA was still protective. This protection was dependent on activation of p38, ERK MAPK, and PI3K pathways, but independent of competition on the cell membrane, NF-kappaB activation, and transcription. In conclusion, TUDCA contributes to the protection against GCDCA-induced mitochondria-controlled apoptosis by activating survival pathways.

Topics: Animals; Apoptosis; Bile Acids and Salts; Carrier Proteins; Caspase 3; Caspase 9; Caspase Inhibitors; Caspases; Cell Membrane; Cell Survival; Glycochenodeoxycholic Acid; Hepatocytes; Male; Membrane Transport Proteins; Mitochondria; Mitogen-Activated Protein Kinases; Organic Anion Transporters, Sodium-Dependent; p38 Mitogen-Activated Protein Kinases; Rats; Rats, Wistar; Symporters; Taurochenodeoxycholic Acid

Neurotoxicity associated with increased glutamate release results in cell death through both necrotic and apoptotic processes. In addition, tauroursodeoxycholic acid (TUDCA), an endogenous bile acid, is a strong modulator of apoptosis in several cell types. The aims of this study were to test the hypothesis that TUDCA reduces the apoptotic threshold induced by glutamate in rat cortical neurons and examine potential transduction pathways involved in both apoptotic signaling and neuroprotection by TUDCA. The results demonstrated that exposure of cortical neurons to glutamate induced cytochrome c release and caspase activation, as well as morphologic changes of apoptosis. These events were associated with down-regulation of antiapoptotic members of the Bcl-2 family, Bcl-2 and Bcl-x(L), and dephosphorylation of the serine/threonine protein kinase Akt. Pretreatment with TUDCA significantly reduced glutamate-induced apoptosis of rat cortical neurons. In addition, TUDCA induced marked phosphorylation and translocation of Bad from mitochondria to the cytosol. Moreover, inhibition of the phosphatidylinositol 3-kinase (PI3K) survival pathway abrogated the protective effects of TUDCA, including phosphorylation and translocation of Bad. In conclusion, TUDCA appears to modulate glutamate-induced neuronal apoptosis, in part, by activating a PI3K-dependent Bad signaling pathway. These data suggest that TUDCA may be beneficial in treating neurodegenerative disorders in which increased glutamate levels contribute to the pathogenesis of the disease.

Topics: Animals; Apoptosis; bcl-Associated Death Protein; Bile Acids and Salts; Biological Transport; Carrier Proteins; Cerebral Cortex; Down-Regulation; Glutamates; Glutamic Acid; Neurons; Phosphatidylinositol 3-Kinases; Phosphorylation; Proto-Oncogene Proteins c-bcl-2; Rats; Rats, Wistar; Taurochenodeoxycholic Acid

Amyloid beta-peptide (Abeta)-induced cell death may involve activation of the E2F-1 transcription factor and other cell cycle-related proteins. In previous studies, we have shown that tauroursodeoxycholic acid (TUDCA), an endogenous bile acid, modulates Abeta-induced apoptosis by interfering with crucial events of the mitochondrial pathway. In this study, we examined the role of E2F and p53 activation in the induction of apoptosis by Abeta, and investigated novel molecular targets for TUDCA. The results showed that despite Bcl-2 up-regulation, PC12 neuronal cells underwent significant apoptosis after incubation with the active fragment Abeta (25-35), as assessed by DNA fragmentation, nuclear morphology and caspase-3-like activation. In addition, transcription through the E2F-1 promoter was significantly induced and associated with loss of the retinoblastoma protein. In contrast, levels of E2F-1, p53 and Bax proteins were markedly increased. Overexpression of E2F-1 in PC12 cells was sufficient to induce p53 and Bax proteins, as well as nuclear fragmentation. Notably, TUDCA modulated Abeta-induced apoptosis, E2F-1 induction, p53 stabilization and Bax expression. Further, TUDCA protected PC12 cells against p53- and Bax-dependent apoptosis induced by E2F-1 and p53 overexpression, respectively. In conclusion, the results demonstrate that Abeta-induced apoptosis of PC12 cells proceeds through an E2F-1/p53/Bax pathway, which, in turn, can be specifically inhibited by TUDCA, thus underscoring its potential therapeutic use.

Topics: Amyloid beta-Peptides; Animals; Apoptosis; bcl-2-Associated X Protein; Cell Cycle Proteins; DNA-Binding Proteins; E2F Transcription Factors; E2F1 Transcription Factor; Gene Expression; Neuroprotective Agents; Nuclear Proteins; PC12 Cells; Peptide Fragments; Proto-Oncogene Proteins; Proto-Oncogene Proteins c-bcl-2; Proto-Oncogene Proteins c-mdm2; Rats; Signal Transduction; Taurochenodeoxycholic Acid; Transcription Factors; Tumor Suppressor Protein p53

Colchicine, an inhibitor of intracellular vesicular transport, has been reported to inhibit the biliary excretion of bile acids and organic anions, but the previous findings are controversial. In order to systematically evaluate the effect of colchicine on the biliary excretion of cholephilic compounds, we studied the effect of colchicine on the biliary excretion of substrates of various canalicular transporters, which were administered at or above the excretory maximum in rats.. Substrates of various canalicular adenosine triphosphate-binding-cassette transporters were infused at or above the rate of maximum excretion into rats, and the effect of colchicine (0.2 mg/100 g), which was intraperitoneally injected 3 h before, on the biliary excretion was studied. Furthermore, the effect of tauroursodeoxycholate (TUDC) co-infusion on the biliary excretion of taurocholate (TC) after colchicine treatment was also studied.. The biliary excretion of TC and cholate administered at the rate of 1 micro mol/min/100 g was markedly inhibited by colchicine, whereas that of TUDC was not inhibited even with the infusion rate of 2 micro mol/min/100 g. TUDC co-infusion at the rate of 1 micro mol/min/100 g increased the biliary excretion of TC (1 micro mol/min/100 g), which was decreased by the colchicine pretreatment. The biliary excretory maximum of taurolithocholate-sulfate and sulfobromophthalein, substrates of the multidrug resistance protein 2, of erythromycin, a substrate of the P-glycoprotein, and of indocyanine green were not affected by colchicine.. The different excretory maximums of TC and TUDC and the different effect of colchicine on the excretion of these bile acids are considered to be a result of different regulatory mechanisms of vesicular targeting of the bile salt export pump to the canalicular membrane by these bile acid conjugates. The vesicular targeting of the multidrug resistance protein 2 and the P-glycoprotein to the canalicular membrane is considered to be colchicine insensitive in the absence of bile acid coadministration.

Topics: Analysis of Variance; Animals; ATP Binding Cassette Transporter, Subfamily B, Member 1; Bile; Bile Acids and Salts; Colchicine; Erythromycin; Indocyanine Green; Male; Rats; Rats, Sprague-Dawley; Sulfobromophthalein; Taurochenodeoxycholic Acid; Taurocholic Acid; Taurolithocholic Acid

Peroxisome proliferator-activated receptor alpha (PPARalpha) is a nuclear receptor that controls expression of genes involved in lipid metabolism and is activated by fatty acids and hypolipidaemic fibrates. Fibrates induce the hepatic expression of murine multidrug resistance 2 ( Mdr2 ), encoding the canalicular phospholipid translocator. The physiological role of PPARalpha in regulation of Mdr2 and other genes involved in bile formation is unknown. We found no differences in hepatic expression of the ATP binding cassette transporter genes Mdr2, Bsep (bile salt export pump), Mdr1a / 1b, Abca1 and Abcg5 / Abcg8 (implicated in cholesterol transport), the bile salt-uptake systems Ntcp (Na(+)-taurocholate co-transporting polypeptide gene) and Oatp1 (organic anion-transporting polypeptide 1 gene) or in bile formation between wild-type and Ppar alpha((-/-)) mice. Upon treatment of wild-type mice with ciprofibrate (0.05%, w/w, in diet for 2 weeks), the expression of Mdr2 (+3-fold), Mdr1a (+6-fold) and Mdr1b (+11-fold) mRNAs was clearly induced, while that of Oatp1 (-5-fold) was reduced. Mdr2 protein levels were increased, whereas Bsep, Ntcp and Oatp1 were drastically decreased. Exposure of cultured wild-type mouse hepatocytes to PPARalpha agonists specifically induced Mdr2 mRNA levels and did not affect expression of Mdr1a / 1b. Altered transporter expression in fibrate-treated wild-type mice was associated with a approximately 400% increase in bile flow: secretion of phospholipids and cholesterol was increased only during high-bile-salt infusions. No fibrate effects were observed in Ppar alpha((-/-)) mice. In conclusion, our results show that basal bile formation is not affected by PPARalpha deficiency in mice. The induction of Mdr2 mRNA and Mdr2 protein levels by fibrates is mediated by PPARalpha, while the induction of Mdr1a / 1b in vivo probably reflects a secondary phenomenon related to chronic PPARalpha activation.

Topics: Animals; ATP Binding Cassette Transporter 1; ATP Binding Cassette Transporter, Subfamily B; ATP Binding Cassette Transporter, Subfamily B, Member 11; ATP Binding Cassette Transporter, Subfamily G, Member 5; ATP Binding Cassette Transporter, Subfamily G, Member 8; ATP-Binding Cassette Sub-Family B Member 4; ATP-Binding Cassette Transporters; Bile; Carrier Proteins; Cells, Cultured; Clofibric Acid; Fibric Acids; Hepatocytes; Lipid Metabolism; Lipoproteins; Liver; Male; Membrane Transport Proteins; Mice; Mice, Mutant Strains; Organ Size; Organic Anion Transporters, Sodium-Dependent; Organic Anion Transporters, Sodium-Independent; Peroxisome Proliferators; Pyrimidines; Receptors, Cytoplasmic and Nuclear; Symporters; Taurochenodeoxycholic Acid; Transcription Factors

Fluid and ion secretion in the gallbladder is mainly triggered by the intracellular second messenger cAMP. We examined the action of bile salts on the cAMP-dependent pathway in the gallbladder epithelium. Primary cultures of human gallbladder epithelial cells were exposed to agonists of the cAMP pathway and/or to bile salts. Taurochenodeoxycholate and tauroursodeoxycholate increased forskolin-induced cAMP accumulation to a similar extent, without affecting cAMP basal levels. This potentiating effect was abrogated after PKC inhibition, whereas both taurochenodeoxycholate and tauroursodeoxycholate induced PKC-alpha and -delta translocation to cell membranes. Consistent with a PKC-mediated stimulation of cAMP production, the expression of six adenylyl cyclase isoforms, including PKC-regulated isoforms 5 and 7, was identified in human gallbladder epithelial cells. cAMP-dependent chloride secretion induced by isoproterenol, a beta-adrenergic agonist, was significantly increased by taurochenodeoxycholate and by tauroursodeoxycholate. In conclusion, endogenous and therapeutic bile salts via PKC regulation of adenylyl cyclase activity potentiate cAMP production in the human gallbladder epithelium. Through this action, bile salts may increase fluid secretion in the gallbladder after feeding.

Topics: Adenylyl Cyclases; Adrenergic beta-Agonists; Bile Acids and Salts; Cells, Cultured; Chlorides; Cyclic AMP; Epithelium; Gallbladder; Humans; Immunoassay; Isoenzymes; Isoproterenol; Protein Kinase C; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Signal Transduction; Stimulation, Chemical; Taurochenodeoxycholic Acid

Hydrophobic bile acids, which are known to be cytotoxic for hepatocytes, are retained in high amount in the liver during cholestasis. Thus, we have investigated the effects of bile acids with various hydrophobicities on biliary epithelial cells. Biliary epithelial cells were cultured in the presence of tauroursodeoxycholate (TUDC), taurocholate (TC), taurodeoxycholate (TDC), taurochenodeoxycholate (TCDC), or taurolithocholate (TLC). Cell proliferation, viability, apoptosis and secretion of monocyte chemotactic protein-1 (MCP-1) and of interleukin-6 (IL-6) were studied. Cell proliferation was increased by TDC, and markedly decreased by TLC in a dose dependent manner (50-500 microM). Cell viability was significantly decreased by TLC and TCDC at 500 microM. TLC, TDC and TCDC induced apoptosis at high concentrations. The secretion of MCP-1 and IL-6 was markedly stimulated by TC. TUDC had no significant effect on any parameter. These findings demonstrate that hydrophobic bile acids were cytotoxic and induced apoptosis of biliary epithelial cells. Furthermore, TC, a major biliary acid in human bile, stimulated secretion of cytokines involved in the inflammatory and fibrotic processes occurring during cholestatic liver diseases.

Topics: Animals; Apoptosis; Bile Acids and Salts; Bile Ducts; Cell Division; Cell Line, Transformed; Chemokine CCL2; Cytokines; Epithelial Cells; Interleukin-6; Mice; Mice, Transgenic; Taurochenodeoxycholic Acid; Taurocholic Acid; Taurodeoxycholic Acid; Taurolithocholic Acid

Taurohyodeoxycholate (THDCA) and tauroursodeoxycholate (TUDCA) induce more bile flow per molecule excreted compared to endogenous bile acids. The aim of this study is to determine if the hypercholeretic effect of tauroursodeoxycholate or taurohyodeoxycholate in normal and bile duct ligated (BDL) rats is due to increased ductal secretion.. Normal or BDL rats were infused with tauroursodeoxycholate or taurohyodeoxycholate and bile flow, bicarbonate, bile salt, cholesterol, and phospholipid secretion were measured. Cholangiocytes were stimulated with taurohyodeoxycholate or tauroursodeoxycholate, and secretin-stimulated secretion was measured.. Taurohyodeoxycholate and tauroursodeoxycholate increased bile flow more in BDL than normal rats. Tauroursodeoxycholate increased bicarbonate secretion more in BDL compared to normal rats. Taurohyodeoxycholate when infused with taurocholate increased bile flow (but not phospholipid excretion) to a greater degree in BDL compared to normal rats. Taurohyodeoxycholate and tauroursodeoxycholate decreased secretin-stimulated cholangiocyte secretion.. Consistent with a ductal origin for bile acid-induced hypercholeresis, taurohyodeoxycholate and tauroursodeoxycholate produced a greater hypercholeresis in BDL than normal rats. Tauroursodeoxycholate- (but not taurohyodeoxycholate-) stimulated hypercholeresis is associated with increased HCO(3)(-) secretion. Tauroursodeoxycholate increases biliary HCO(3)(-) secretion by a mechanism unrelated to secretin-stimulated cholangiocyte secretion. Taurohyodeoxycholate-induced hypercholeresis in BDL rats is unrelated to enhanced phospholipid excretion.

Topics: Animals; ATP Binding Cassette Transporter, Subfamily B; ATP-Binding Cassette Transporters; Bicarbonates; Bile; Bile Acids and Salts; Bile Duct Diseases; Bile Ducts; Cholesterol; Epithelial Cells; Gene Expression; Hepatocytes; Ligation; Male; Phospholipids; Rats; Rats, Inbred F344; Secretin; Taurochenodeoxycholic Acid; Taurodeoxycholic Acid

Taurolithocholic acid (TLCA) is a potent cholestatic agent. Our recent work suggested that TLCA impairs hepatobiliary exocytosis, insertion of transport proteins into apical hepatocyte membranes, and bile flow by protein kinase Cepsilon (PKCepsilon)-dependent mechanisms. Products of phosphatidylinositol 3-kinases (PI3K) stimulate PKCepsilon. We studied the role of PI3K for TLCA-induced cholestasis in isolated perfused rat liver (IPRL) and isolated rat hepatocyte couplets (IRHC). In IPRL, TLCA (10 micromol/liter) impaired bile flow by 51%, biliary secretion of horseradish peroxidase, a marker of vesicular exocytosis, by 46%, and the Mrp2 substrate, 2,4-dinitrophenyl-S-glutathione, by 95% and stimulated PI3K-dependent protein kinase B, a marker of PI3K activity, by 154% and PKCepsilon membrane binding by 23%. In IRHC, TLCA (2.5 micromol/liter) impaired canalicular secretion of the fluorescent bile acid, cholylglycylamido fluorescein, by 50%. The selective PI3K inhibitor, wortmannin (100 nmol/liter), and the anticholestatic bile acid tauroursodeoxycholic acid (TUDCA, 25 micromol/liter) independently and additively reversed the effects of TLCA on bile flow, exocytosis, organic anion secretion, PI3K-dependent protein kinase B activity, and PKCepsilon membrane binding in IPRL. Wortmannin also reversed impaired bile acid secretion in IRHC. These data strongly suggest that TLCA exerts cholestatic effects by PI3K- and PKCepsilon-dependent mechanisms that are reversed by tauroursodeoxycholic acid in a PI3K-independent way.

Topics: Androstadienes; Animals; Anions; Bile Acids and Salts; Cell Membrane; Cholagogues and Choleretics; Enzyme Activation; Enzyme Inhibitors; Exocytosis; Hepatocytes; Horseradish Peroxidase; Kinetics; Liver; Male; Perfusion; Phosphatidylinositol 3-Kinases; Precipitin Tests; Protein Binding; Protein Serine-Threonine Kinases; Protein Transport; Proto-Oncogene Proteins; Proto-Oncogene Proteins c-akt; Rats; Rats, Sprague-Dawley; Taurochenodeoxycholic Acid; Taurolithocholic Acid; Time Factors; Wortmannin

Bax is a potent pro-apoptotic member of the Bcl-2 protein family that localizes to the mitochondrial membrane during apoptosis. Tauroursodeoxycholic acid (TUDCA) modulates the apoptotic threshold, in part, by preventing Bax translocation both in vitro and in vivo. The mechanisms by which Bax induces and TUDCA inhibits release of cytochrome c are unclear. We show here that recombinant Bax protein induced cytochrome c release in isolated mitochondria without detectable swelling. Co-incubation with TUDCA prevented efflux of mitochondrial factors and proteolytic processing of caspases in cytosolic extracts. Spectroscopic analyses of mitochondria exposed to Bax revealed increased polarity and fluidity of the membrane lipid core as well as altered protein order, indicative of Bax binding, together with loss of spin-label paramagnetism, characteristic of oxidative damage. TUDCA markedly abrogated the Bax-induced membrane perturbation. In conclusion, our results indicate that Bax protein directly induces cytochrome c release from mitochondria through a mechanism that does not require the permeability transition. Rather, it is accompanied by changes in the organization of membrane lipids and proteins. TUDCA is a potent inhibitor of Bax association with mitochondria. Thus, TUDCA modulates apoptosis by suppressing mitochondrial membrane perturbation through pathways that are also independent of the mitochondrial permeability transition.

Topics: Animals; Apoptosis; bcl-2-Associated X Protein; Caspases; Cytochrome c Group; Cytosol; Enzyme Activation; Humans; Intracellular Membranes; Male; Membrane Lipids; Membrane Potentials; Mitochondria, Liver; Mitochondrial Swelling; Oxidation-Reduction; Permeability; Protein Binding; Protein Processing, Post-Translational; Proteins; Proto-Oncogene Proteins; Proto-Oncogene Proteins c-bcl-2; Rats; Rats, Wistar; Recombinant Proteins; Taurochenodeoxycholic Acid

Tauroursodeoxycholic acid (TUDCA), an endogenous bile acid, modulates cell death by interrupting classic pathways of apoptosis. Intracerebral hemorrhage (ICH) is a devastating acute neurological disorder, without effective treatment, in which a significant loss of neuronal cells is thought to occur by apoptosis. In this study, we evaluated whether TUDCA can reduce brain injury and improve neurological function after ICH in rats. Administration of TUDCA before or up to 6 h after stereotaxic collagenase injection into the striatum reduced lesion volumes at 2 days by as much as 50%. Apoptosis was approximately 50% decreased in the area immediately surrounding the hematoma and was associated with a similar inhibition of caspase activity. These changes were also associated with improved neurobehavioral deficits as assessed by rotational asymmetry, limb placement, and stepping ability. Furthermore, TUDCA treatment modulated expression of certain Bcl-2 family members, as well as NF-kappaB activity. In addition to its protective action at the mitochondrial membrane, TUDCA also activated the Akt-1protein kinase Balpha survival pathway and induced Bad phosphorylation at Ser-136. In conclusion, reduction of brain injury underlies the wide-range neuroprotective effects of TUDCA after ICH. Thus, given its clinical safety, TUDCA may provide a potentially useful treatment in patients with hemorrhagic stroke and perhaps other acute brain injuries associated with cell death by apoptosis.

Topics: Animals; Apoptosis; Bile; Brain; Caspases; Cerebral Hemorrhage; Cholagogues and Choleretics; Collagenases; Disease Models, Animal; DNA Primers; Female; In Situ Nick-End Labeling; Proto-Oncogene Proteins c-bcl-2; Rats; Rats, Sprague-Dawley; Reverse Transcriptase Polymerase Chain Reaction; Substrate Specificity; Taurochenodeoxycholic Acid

Stimulation of canalicular secretion by tauroursodeoxycholate (TUDC) involves dual activation of p38 mitogen-activated protein kinase (p38(MAPK)) and extracellular signal-regulated kinase (ERK). This study investigates the sensing and upstream signaling events of TUDC-induced choleresis.. TUDC and hypo-osmolarity effects on protein kinase activities and taurocholate excretion were studied in perfused rat liver.. TUDC induced a rapid activation of focal adhesion kinase (FAK) and Src, as shown by an increase in Y418 phosphorylation and a decrease in Y529 phosphorylation of Src. Inhibition of Src by PP-2 abolished the TUDC-induced activation of p38(MAPK) but not of FAK and ERKs. An integrin-inhibitory peptide with an RGD motif blocked TUDC-induced FAK, Src, ERK, and p38(MAPK) activation, suggesting that integrin signaling toward FAK/Src is required for TUDC-induced MAPK activation. The RGD peptide and PP-2 also abolished the stimulation of taurocholate excretion in perfused rat liver in response to TUDC. Integrin-dependent Src activation was also identified as an upstream event in hypo-osmotic signaling toward MAPKs and choleresis.. TUDC-induced stimulation of canalicular taurocholate excretion involves integrin sensing, FAK, and Src activation as upstream events for dual MAPK activation. Integrins may also represent one long-searched sensor for cell hydration changes in response to hypo-osmolarity.

Topics: Animals; Bile Canaliculi; Cholagogues and Choleretics; Focal Adhesion Kinase 1; Focal Adhesion Protein-Tyrosine Kinases; Integrins; Liver; Male; MAP Kinase Signaling System; Protein-Tyrosine Kinases; Rats; Rats, Wistar; src-Family Kinases; Taurochenodeoxycholic Acid; Water-Electrolyte Balance

To investigate the effect of Tauroursodeoxycholic acid (TUDCA) on Taurodeoxycholic acid (TDCA)-induced HepG2 cell apoptosis and to clarify the molecular mechanism of its anti-apoptosis effect of TUDCA.. Morphologic evaluation of apoptotic cells was performed by Hoechst 33258 staining and electron microscope. DNA fragment was detected by electrophoresis on 1.5% agarose gels. Apoptosis rate was measured by flow cytometry using PI dye. Following incubation of HepG2 cells either with TDCA alone, or coincubation with TUDCA and TDCA, the releasing level of cytochrome c from mitochondria into cytosol was determined by western blot, also the activity of caspase-3, 8, 9.. Incubating the cells with 400 micromol/L TDCA for 12 h induced the cells apoptosis significantly. The apoptotic rate decreased from 50.35% +/- 2.20% to 13.78% +/- 0.84% after coincubation with TUDCA, and this anti-apoptotic effect of TUDCA was confirmed by morphological and DNA ladder detection. TUDCA significantly inhibited the release of cytochrome C from mitochondria into cytosol, and the activity of caspase-9, 3 (t > or = 13.00, P < 0.01), especially at 12 h, caspase-3 activity decreased by 54.9% (t = 16.88, P < 0.01) and 52.5%, however it had no obvious effect on the activity of caspase-8 (t = 1.94, P > 0.05).. TUDCA prevents HepG2 cells apoptosis induced by TDCA through modulating mitochondrial membrane stability, inhibiting the release of cytochrome c and the activation of procaspase-9 and 3. Anti-apoptotic mechanism of TUDCA may be considered to be one of the most important reasons that TUDCA exerts significant efficacy in the treatment of cholestatic liver diseases.

Topics: Apoptosis; Carcinoma, Hepatocellular; Caspase 3; Caspase 9; Caspases; Cytochromes c; Humans; Liver Neoplasms; Taurochenodeoxycholic Acid; Taurodeoxycholic Acid; Tumor Cells, Cultured

To examine the extent and mechanisms of apoptosis in cholestatic liver injury and to explore the role of the transcription factor nuclear factor-kappa B in protection against bile acid-induced apoptosis.. Cholestatic liver injury was induced by bile duct ligation in Wistar rats. Furthermore, primary cultures of rat hepatocytes were exposed to glycochenodeoxycholic acid (GCDCA), tauroursodeoxycholic acid (TUDCA), taurochenodeoxycholic acid (TCDCA) and to cytokines. Apoptosis was determined by TUNEL-staining, active caspase-3 staining, activation of caspase-8, -9 and -3.. Limited hepatocyte apoptosis and an increased expression of NF-kappaB-regulated anti-apoptotic genes A1 and cIAP2 were detected in cholestatic rat livers. Bcl-2 expression was restricted to bile duct epithelium. In contrast to TCDCA and TUDCA, GCDCA induced apoptosis in a Fas-associated protein with death domain (FADD)-independent pathway in hepatocytes. Although bile acids do not activate NF-kappaB, NF-kappaB activation by cytokines (induced during cholestasis) protected against GCDCA-induced apoptosis in vitro by upregulating A1 and cIAP2.. GCDCA induces apoptosis in a mitochondria-controlled pathway in which caspase-8 is activated in a FADD-independent manner. However, bile acid-induced apoptosis in cholestasis is limited. This could be explained by cytokine-induced activation of NF-kappaB-regulated anti-apoptotic genes like A1 and cIAP2.

Topics: Adaptor Proteins, Signal Transducing; Animals; Apoptosis; Carrier Proteins; Cells, Cultured; Cholestasis; Cytokines; Disease Models, Animal; Fas-Associated Death Domain Protein; Gene Expression; Glycochenodeoxycholic Acid; Hepatocytes; Male; NF-kappa B; Rats; Rats, Wistar; Specific Pathogen-Free Organisms; Taurochenodeoxycholic Acid

Bile duct epithelium is physiologically exposed to high concentrations of bile salts, suggesting the presence of a cytoprotective mechanism(s). The aim of this study was to clarify whether bile salts cause bile duct cell damage and to elucidate the mechanism(s) providing protection against such an action of bile salts. Immortalized mouse cholangiocytes were incubated with taurocholate, taurochenodeoxycholate, glycochenodeoxycholate (GCDC), taurodeoxycholate, and tauroursodeoxycholate (TUDC), followed by flow-cytometric analysis and caspase activity assay to evaluate the induction of apoptosis. GCDC time-dependently induced caspase 3 (3.4-fold)- and caspase 9 (1.4-fold)-mediated apoptosis of cholangiocytes, but this was inhibited by lecithins and TUDC. Further, expression of cholangiocyte bile salt transporters (apical sodium-dependent bile salt transporter [Asbt] and multidrug resistance protein 3 [Mrp3]) was examined by RT-PCR and western blotting, and cholangiocyte bile salt uptake was determined using radiolabeled bile salts. Expression of cholangiocyte Asbt and Mrp3 was increased by bile salts, whereas lecithins interestingly reduced bile salt uptake to inhibit cholangiocyte apoptosis. In conclusion, bile salts themselves cause cholangiocyte apoptosis when absorbed by and retained inside the cell, but this is inhibited by washing out cytotoxic bile salts according to Mrp3, a rescue exporting molecule. Biliary lecithin is seemingly another cytoprotective player against cytotoxic bile salts, reducing their uptake, and this is associated with a reduced expression of Mrp3.

Topics: Animals; Apoptosis; Bile Acids and Salts; Bile Ducts; Blotting, Western; Carbon Radioisotopes; Carrier Proteins; Caspase 9; Caspases; DNA Primers; Dose-Response Relationship, Drug; Epithelium; Flow Cytometry; Glycochenodeoxycholic Acid; Mice; Mice, Inbred BALB C; Multidrug Resistance-Associated Proteins; Organic Anion Transporters, Sodium-Dependent; Phosphatidylcholines; Reverse Transcriptase Polymerase Chain Reaction; Symporters; Taurochenodeoxycholic Acid; Taurocholic Acid; Taurodeoxycholic Acid

The hydrophilic bile salt ursodeoxycholate is frequently used to dissolve cholesterol gallstones. We have now quantitated crystallization as a function of bile salt hydrophobicity, phospholipid content, cholesterol saturation and total lipid concentration (TLCo).. Crystallization in supersaturated model biles with low phospholipid contents (left two-phase-micelles and crystal-containing-zone) was assessed during 21 days by microscopy and chemical measurement of crystal mass. For model biles with higher phospholipid contents (central three-phase-micelles, vesicles and crystal-containing-zone), lipid distribution into various phases was determined by combined ultracentrifugation-filtration-dialysis methodology (Biochim. Biophys. Acta 1532 (2001) 15-27).. In the left two-phase zone, crystal numbers and masses were highest in case of more hydrophilic bile salt composition (TUDC 100%>TC/TUDC 70%/30%>TC 100%>TC/TDC 70%/30%>TDC 100%) and decreased with increasing phospholipid contents, lower TLCo and lower cholesterol saturation index (CSI). In contrast, in the presence of vesicles (three-phase zone), crystallization decreased at increasing bile salt hydrophilicity, with concomitant increased vesicular cholesterol solubilization.. Presence of vesicular phases is a prerequisite for inhibition of cholesterol crystallization by tauroursodeoxycholate.

Topics: Bile Acids and Salts; Cholelithiasis; Cholesterol; Crystallization; Hydrophobic and Hydrophilic Interactions; Micelles; Phosphatidylcholines; Taurochenodeoxycholic Acid; Taurocholic Acid; Taurodeoxycholic Acid

Huntington's disease (HD) is an untreatable neurological disorder caused by selective and progressive degeneration of the caudate nucleus and putamen of the basal ganglia. Although the etiology of HD pathology is not fully understood, the observed loss of neuronal cells is thought to occur primarily through apoptosis. Furthermore, there is evidence in HD that cell death is mediated through mitochondrial pathways, and mitochondrial deficits are commonly associated with HD. We have previously reported that treatment with tauroursodeoxycholic acid (TUDCA), a hydrophilic bile acid, prevented neuropathology and associated behavioral deficits in the 3-nitropropionic acid rat model of HD. We therefore examined whether TUDCA would also be neuroprotective in a genetic mouse model of HD. Our results showed that systemically administered TUDCA led to a significant reduction in striatal neuropathology of the R6/2 transgenic HD mouse. Specifically, R6/2 mice began receiving TUDCA at 6 weeks of age and exhibited reduced striatal atrophy, decreased striatal apoptosis, as well as fewer and smaller size ubiquitinated neuronal intranuclear huntingtin inclusions. Moreover, locomotor and sensorimotor deficits were significantly improved in the TUDCA-treated mice. In conclusion, TUDCA is a nontoxic, endogenously produced hydrophilic bile acid that is neuroprotective in a transgenic mouse model of HD and, therefore, may provide a novel and effective treatment in patients with HD.

Topics: Animals; Apoptosis; Bile Acids and Salts; Cell Nucleus; Corpus Striatum; Disease Models, Animal; Huntington Disease; Male; Mice; Mice, Transgenic; Motor Activity; Nerve Degeneration; Neurons; Neuroprotective Agents; Taurochenodeoxycholic Acid

It has been demonstrated that plasma from patients with fulminant hepatic failure (FHF) interferes extensively with cellular function. We placed primary human and primary porcine hepatocytes in a polyurethane foam (PUF)/spheroid culture system and compared the metabolic functions in the plasma of patients with FHF in a 24-h stationary culture to those in a monolayer culture. The PUF/spheroid culture system using primary human and primary porcine hepatocytes significantly decreased ammonia content during 28-day culture. Fisher's ratio significantly increased at culture days 3 and 7. Tauroursodeoxycholic acid significantly increased and glycochenodeoxycholic acid and taurochenodeoxycholic acid decreased in the FHF patients' plasma at culture day 3. During at least a 24-h culture in the FHF patients' plasma, metabolic functions of primary human and primary porcine hepatocytes were almost identical. The present results indicate that the PUF/spheroid culture system using primary human or primary porcine hepatocytes demonstrated more advantageous metabolic functions in the plasma from patients with FHF than the monolayer culture.

Topics: Ammonia; Animals; Bile Acids and Salts; Cell Culture Techniques; Cells, Cultured; Glycochenodeoxycholic Acid; Hepatocytes; Humans; Liver Failure; Polyurethanes; Spheroids, Cellular; Swine; Taurochenodeoxycholic Acid; Time Factors

Activation of death receptors and mitochondrial damage are well-described common apoptotic pathways. Recently, a novel pathway via endoplasmic reticulum (ER) stress has been reported. We assessed the role of tauroursodeoxycholic acid (TUDCA) in inhibition of caspase-12 activation and its effect on calcium homeostasis in an ER stress-induced model of apoptosis. The human liver-derived cell line, Huh7, was treated with thapsigargin (TG) to induce ER stress. Typical morphologic changes of ER stress preceded development of apoptotic changes, including DNA fragmentation and cleavage of poly (adenosine diphosphate-ribose) polymerase (PARP), as well as activation of caspase-3 and -7. Elevation of intracellular calcium levels without loss of mitochondrial membrane potential (MMP) was shown using Fluo-3/Fura-red labeling and flow cytometry, and confirmed by induction of Bip/GRP78, a calcium-dependent chaperon of ER lumen. These changes were accompanied by procaspase-12 processing. TUDCA abolished TG-induced markers of ER stress; reduced calcium efflux, induction of Bip/GRP78, and caspase-12 activation; and subsequently inhibited activation of effector caspases and apoptosis. In conclusion, we propose that mitochondria play a secondary role in ER-mediated apoptosis and that TUDCA prevents apoptosis by blocking a calcium-mediated apoptotic pathway as well as caspase-12 activation. This novel mechanism of TUDCA action suggests new intervention methods for ER stress-induced liver disease.

Topics: Apoptosis; Calcium; Caspase 12; Caspase 3; Caspase 7; Caspases; Cell Line; Cholagogues and Choleretics; Endoplasmic Reticulum; Endoplasmic Reticulum Chaperone BiP; Enzyme Activation; Enzyme Inhibitors; Hepatocytes; Humans; Liver Diseases; Microscopy, Electron; Mitochondria; Taurochenodeoxycholic Acid; Thapsigargin

We investigated the effects of tauroursodeoxycholic acid (TUDCA) to assess whether this acid may also have "protective" effects similar to those found with ursodeoxycholic acid (UDCA). We used a well-known amphibian model of gastric mucosa, and studied the effects of taurodeoxycholic acid (TDCA) on electrical transepithelial parameters, acid secretion and histology in absence or in presence of TUDCA. Mucosal exposure to TDCA, after stimulation with histamine, caused a reduction in transepithelial potential difference (V(t)) and transepithelial resistance (R(t)) and a decrease in acid secretion while mucosal exposure to TUDCA did not cause a significant change in the electrical parameters. Moreover, TDCA primarily affected the neck cells, while TUDCA affected only oxyntic cells, causing a similar degree of injury to that observed in controls. Mucosal exposure to TUDCA plus TDCA caused a reduction in short circuit current (I(sc)) and R(t), whereas acid secretion did not change. These results suggest that: (1) TUDCA reduces the damaging effects of TDCA on fundus gastric mucosa; (2) TUDCA may play an important role in the treatment of gastritis associated with bile reflux.

Topics: Animals; Bile Acids and Salts; Cholagogues and Choleretics; Electrophysiology; Gastric Fundus; Gastric Mucosa; Rana esculenta; Taurochenodeoxycholic Acid

Tauroursodeoxycholic acid (TUDCA), a hydrophilic bile acid, is a strong modulator of apoptosis in both hepatic and nonhepatic cells, and appears to function by inhibiting mitochondrial membrane perturbation. Excitotoxicity, metabolic compromise, and oxidative stress are major determinants of cell death after brain ischemia-reperfusion injury. However, some neurons undergo delayed cell death that is characteristic of apoptosis. Therefore, the authors examined whether TUDCA could reduce the injury associated with acute stroke in a well-characterized model of transient focal cerebral ischemia. Their model of middle cerebral artery occlusion resulted in marked cell death with prominent terminal deoxynucleotidyl transferase-mediated 2;-deoxyuridine 5;-triphosphate-biotin nick end labeling (TUNEL) within the ischemic penumbra, mitochondrial swelling, and caspase activation. Tauroursodeoxycholic acid administered 1 hour after ischemia resulted in significantly increased bile acid levels in the brain, improved neurologic function, and an approximately 50% reduction in infarct size 2 and 7 days after reperfusion. In addition, TUDCA significantly reduced the number of TUNEL-positive brain cells, mitochondrial swelling, and partially inhibited caspase-3 processing and substrate cleavage. These findings suggest that the mechanism for in vivo neuroprotection by TUDCA is, in part, mediated by inhibition of mitochondrial perturbation and subsequent caspase activation leading to apoptotic cell death. Thus, TUDCA, a clinically safe molecule, may be useful in the treatment of stroke and possibly other apoptosis-associated acute and chronic injuries to the brain.

Topics: Animals; Apoptosis; Brain; Caspases; Cholagogues and Choleretics; Disease Models, Animal; In Situ Nick-End Labeling; Infarction, Middle Cerebral Artery; Male; Mitochondria; Neurons; Neuroprotective Agents; Poly(ADP-ribose) Polymerases; Rats; Rats, Sprague-Dawley; Stroke; Taurochenodeoxycholic Acid

This study was performed to compare the effects of two hydrophilic bile acids, taurohyodeoxycholic acid (THDCA) and tauroursodeoxycholic acid (TUDCA), on HepG2 cells. Cytotoxicity was evaluated at different times of exposure by incubating cells with increasing concentrations (50-800 micromol/l) of either bile acid, while their cytoprotective effect was tested in comparison with deoxycholic acid (DCA) (350 micromol/l and 750 micromol/l)-induced cytotoxicity. Culture media, harvested at the end of each incubation period, were analyzed to evaluate aspartate transaminase (AST), alanine transaminase and gamma-glutamyltranspeptidase release. In addition, the hemolytic effect of THDCA and TUDCA on human red blood cells was also determined. At 24 h of incubation neither THDCA nor TUDCA was cytotoxic at concentrations up to 200 and 400 micromol/l. At 800 micromol/l both THDCA and TUDCA induced a slight increase in AST release. At this concentration and with time of exposure prolonged up to 72 h, THDCA and TUDCA induced a progressive increase of AST release significantly (P<0.05) higher than that of controls being AST values for THDCA (2.97+/-0.88 time control value (tcv) at 48 h and 4.50+/-1.13 tcv at 72 h) significantly greater than those of TUDCA (1.50+/-0.20 tcv at 48 h and 1.80+/-0.43 tcv at 72 h) (P<0.01). In cytoprotection experiments, the addition of 50 micromol/l THDCA decreased only slightly (-5%) AST release induced by 350 micromol/l DCA, while the addition of 50 micromol/l TUDCA was significantly effective (-23%; P<0.05). Higher doses of THDCA or TUDCA did not reduce toxicity induced by 350 micromol/l DCA, but were much less toxic than an equimolar dose of DCA alone. At the concentration used in this experimental model neither THDCA nor TUDCA was hemolytic; however at a very high concentration (6 mmol/l) both bile acids induced 5-8% hemolysis. We conclude that bile acid molecules with a similar degree of hydrophilicity may show different cytotoxic and cytoprotective properties.

Topics: Alanine Transaminase; Aspartate Aminotransferases; Deoxycholic Acid; Dose-Response Relationship, Drug; Erythrocytes; Hemolysis; Humans; Taurochenodeoxycholic Acid; Taurodeoxycholic Acid; Time Factors; Transglutaminases; Tumor Cells, Cultured

Accumulating bile acids (BA) trigger cholangiocyte proliferation in chronic cholestasis. The aim of this study was to determine if ursodeoxycholate (UDCA) or tauroursodeoxycholate (TUDCA) chronic feeding prevents the increased cholangiocyte growth and secretion in bile duct-ligated (BDL) rats, if UDCA and TUDCA effects are associated with increased cholangiocyte apoptosis, and to determine if this inhibition is dependent on increased intracellular Ca(2+) ([Ca(2+)](i)) and activation of protein kinase C (PKC) alpha. Immediately after BDL, rats were fed UDCA or TUDCA (both 275 micromol/d) for 1 week. We determined the number of bile ducts in liver sections, cholangiocyte proliferation (by measurement of H(3) histone and proliferating cellular nuclear antigen in isolated cholangiocytes), and ductal secretion. In purified cholangiocytes from 1-week BDL rats, we evaluated if UDCA and TUDCA directly inhibit cholangiocyte proliferation and secretin-stimulated adenosine 3', 5'-monophosphate levels. We determined if UDCA and TUDCA activate PKC, increase [Ca(2+)](i), and alter the apical BA transporter (ABAT) expression in cholangiocytes. UDCA and TUDCA inhibited in vivo the cholangiocyte proliferation, secretion, and ABAT expression. In vitro UDCA and TUDCA inhibition of cholangiocyte growth and secretion required increased [Ca(2+)](i) and PKC alpha. In conclusion, activation of Ca(2+)-dependent PKC alpha is required for UDCA and TUDCA inhibition of cholangiocyte growth and secretion. Reduced cholangiocyte ABAT may decrease endogenous BA stimulation of cholangiocyte growth and secretion.

Topics: Animals; Apoptosis; Bile Acids and Salts; Bile Ducts; Calcium; Carrier Proteins; Cell Division; Cholagogues and Choleretics; Cholestasis; Down-Regulation; Hepatitis; Hydroxysteroid Dehydrogenases; Isoenzymes; Ligation; Liver; Male; Membrane Glycoproteins; Organ Size; Protein Kinase C; Protein Kinase C-alpha; Rats; Rats, Inbred F344; Taurochenodeoxycholic Acid; Ursodeoxycholic Acid

Tauroursodeoxycholic acid (TUDCA) may exert anticholestatic effects via Ca(++)- and alpha-protein kinase C (alpha-PKC)-dependent apical vesicular insertion of canalicular transporters in cholestatic hepatocytes (Hepatology 2001; 33: 1206-16). Tauroursodeoxycholic acid is mainly taken up into liver cells by Na(+)-taurocholate cotransporting polypeptide (Ntcp). Tauroursodeoxycholic acid selectively translocates alpha-PKC, a key mediator of regulated exocytosis, to hepatocellular membranes. It is unclear whether TUDCA exerts its effects on alpha-PKC after carrier-mediated uptake into liver cells or by interaction with extracellular/membraneous structures.. Human hepatoblastoma HepG2 cells lacking Ntcp were stably transfected with pcDNA3.1/Ntcp or sham-transfected with pcDNA3.1 [+]. Distribution of alpha-PKC was studied using a Western blotting technique. Uptake of [(3)H]taurocholic acid (TCA) was determined radiochemically.. [(3)H]taurocholic acid uptake was approximately 180-fold higher in Ntcp-transfected than in sham-transfected cells. Phorbol 12-myristate 13-acetate (1 micromol L(-1); positive control) increased membrane binding of alpha-PKC by 34% in Ntcp-transfected and by 37% in sham-transfected cells. Tauroursodeoxycholic acid (10 micromol L(-1)) increased membrane-associated alpha-PKC by 19% in Ntcp-transfected, but not in sham-transfected cells (-13%). Taurocholic acid (10 micromol L(-1)) did not affect the distribution of alpha-PKC.. Carrier-mediated uptake is a prerequisite for TUDCA-induced translocation of alpha-PKC to hepatocellular membranes.

Topics: Biological Transport; Carrier Proteins; Cell Fractionation; Hepatocytes; Humans; Isoenzymes; Membrane Transport Proteins; Organic Anion Transporters, Sodium-Dependent; Protein Kinase C; Protein Kinase C-alpha; Symporters; Taurochenodeoxycholic Acid; Tetradecanoylphorbol Acetate; Transfection; Tritium; Tumor Cells, Cultured

Hydrophobic bile acids impair gallbladder emptying in vivo and inhibit gallbladder muscle contraction in response to CCK-8 in vitro. This study was aimed at determining the mechanisms of muscle cell dysfunction caused by bile acids in guinea pig gallbladders. Muscle cells were obtained by enzymatic digestion. Taurochenodeoxycholic acid (TCDC), a hydrophobic bile acid, caused a contraction of up to 15% and blocked CCK-induced contraction. Indomethacin abolished the TCDC-induced contraction. Hydrophilic bile acid tauroursodeoxycholic acid (TUDC) had no effect on muscle contraction but prevented the TCDC-induced contraction and its inhibition on CCK-induced contraction. Pretreatment with NADPH oxidase inhibitor PH2I, xanthine oxidase inhibitor allopurinol, and free-radical scavenger catalase also prevented TCDC-induced contraction and its inhibition of the CCK-induced contraction. TCDC caused H2O2 production, lipid peroxidation, and increased PGE2 synthesis and activities of catalase and SOD. These changes were significantly inhibited by pretreatment of PH2I or allopurinol. Inhibitors of cytosolic phospholipase A2 (cPLA2), protein kinase C (PKC), and mitogen-activating protein kinase (MAPK) also blocked the TCDC-induced contraction. It is concluded that hydrophobic bile acids cause muscle cell dysfunction by stimulating the formation of H2O2 via activation of NADPH and xanthine oxidase. H2O2 causes lipid peroxidation and activates cPLA2 to increase PGE2 production, which, in turn, stimulates the synthesis of free-radical scavengers through the PKC-MAPK pathway.

Topics: Animals; Bile Acids and Salts; Dinoprostone; Enzyme Inhibitors; Gallbladder; Guinea Pigs; Hydrogen Peroxide; Lipid Peroxides; Muscle Contraction; Muscle, Smooth; Oxidoreductases; Signal Transduction; Taurochenodeoxycholic Acid

There is accumulating evidence showing that the majority of cell death in neural grafts results from apoptosis when cells are implanted into the brain. Tauroursodeoxycholic acid (TUDCA), a taurine-conjugated hydrophilic bile acid, has been found to possess antiapoptotic properties. In the present study we have examined whether the supplementation of TUDCA to cell suspensions prior to transplantation can lead to enhanced survival of nigral grafts. We first conducted an in vitro study to examine the effects of TUDCA on the survival of dopamine neurons in serum-free conditions. The number of tyrosine hydroxylase (TH)-positive neurons in the TUDCA-treated cultures was significantly greater than that of control cultures 7 days in vitro. In addition, a terminal deoxynucleotidyl transferase (TdT)-mediated dUTP-biotin nick end labeling (TUNEL) assay showed that the number of apoptotic cells in the TUDCA-treated cultures was dramatically smaller than that in the control cultures. In the transplantation study, a 50 microM concentration of TUDCA was added to the media when nigral tissue from Sprague-Dawley (SD) rats was trypsinized and dissociated. Two microliters of cell suspension containing TUDCA was then stereotaxically injected into the striatum of adult SD rats subjected to an extensive unilateral 6-hydroxydopamine lesion of the nigrastriatal dopamine pathway. At 2 weeks after transplantation, the rats that received a cell suspension with TUDCA exhibited a significant reduction in amphetamine-induced rotation scores when compared with pretransplantation value. There was a significant increase (approximately threefold) in the number of TH-positive cells in the neural grafts for the TUDCA-treated group when compared with the controls 6 weeks postgrafting. The number of apoptotic cells was much smaller in the graft areas in the TUDCA-treated groups than in the control group 4 days after transplantation. These data demonstrate that pretreatment of the cell suspension with TUDCA can reduce apoptosis and increase the survival of grafted cells, resulting in an improvement of behavioral recovery.

Topics: Amphetamines; Animals; Apoptosis; Behavior, Animal; Brain Tissue Transplantation; Cell Transplantation; Cells, Cultured; Corpus Striatum; Culture Media, Serum-Free; Culture Techniques; Disease Models, Animal; Dopamine; Female; Graft Survival; In Situ Nick-End Labeling; Neurons; Parkinsonian Disorders; Rats; Rats, Sprague-Dawley; Rotation; Substantia Nigra; Taurochenodeoxycholic Acid

Tauroursodeoxycholate (TUDC) provides partial protection against taurolithocholate (TLC) induced cholestasis, possibly by inducing a signalling cascade activating protein kinase C (PKC). The potential protective effects of beta muricholic acid (beta-MC), another 7-beta-hydroxylated bile salt, have not previously been studied in TLC cholestasis.. To study the effect of beta-MC on TLC induced cholestasis and also to investigate further the effects of agents affecting intracellular signalling, notably DBcAMP (a cell permeable cAMP analogue) and several protein kinase inhibitors.. Functional studies were carried out analysing the proportion of hepatocyte couplets able to accumulate the fluorescent bile acid analogue cholyl-lysyl-fluorescein (CLF) into their sealed canalicular vacuole (cVA of CLF assay).. It was found that both beta-MC and DBcAMP were as effective as TUDC in protecting against TLC induced cholestasis. The PKC inhibitors staurosporin and H7 but not the specific protein kinase A (PKA) inhibitor KT5720 abolished the protective effects of TUDC and beta-MC. BAPTA/AM, a chelator of intracellular Ca(2+), significantly decreased the protective effect of both bile salts, and that of DBcAMP. PKC and PKA inhibitors had no effect on protection with DBcAMP.. Beta-MC was as effective as TUDC in protecting against TLC cholestasis. Mobilisation of Ca(2+) and activation of PKC, but not of PKA, are involved in the anticholestatic effect of the two 7-beta-hydroxylated bile salts. The hepatoprotective effects of DBcAMP involved Ca(2+) mobilisation, but not PKC or PKA activation.

Topics: 1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine; Analysis of Variance; Animals; Bucladesine; Calcium; Carbazoles; Chelating Agents; Cholagogues and Choleretics; Cholestasis; Cholic Acids; Cyclic AMP-Dependent Protein Kinases; Egtazic Acid; Enzyme Activation; Enzyme Inhibitors; Indoles; Liver; Male; Protein Kinase C; Pyrroles; Rats; Signal Transduction; Staurosporine; Taurochenodeoxycholic Acid; Taurolithocholic Acid

Ursodeoxycholic acid (UDCA) can protect hepatocytes from apoptosis induced by a variety of stimuli including anti-Fas antibody. However, in vivo the Fas receptor is activated by its natural ligand, Fas-L, whereas anti-Fas antibodies are not a physiologic stimulus. We therefore have assessed the anti-apoptotic effects of UDCA and other bile acids in a novel coculture model where apoptosis is induced in murine hepatocytes by membrane-bound Fas-L expressing fibroblasts. Primary hepatocytes were cultured overnight on collagen-coated coverslips with increasing concentrations of different bile acids and overlaid with either NIH 3T3 Fas-L(+) or Fas-L(-) expressing fibroblasts. After 6 hours cells were fixed and apoptosis was evaluated by TUNEL assay and DAPI staining using digital imaging. Fas-L protein expression and Fas trimerization were evaluated by Western blot analysis. FITC-UDCA and Mitotracker Red were used to evaluate UDCA localization with mitochondria. UDCA (up to 100 micromol/L, P <.0001), TUDCA (up to 400 micromol/L, P <.0001), and TCDCA (up to 200 micromol/L, P <.0001), but not TCA (up to 500 micromol/L), significantly protected hepatocytes in Fas-L(+) cocultures. UDCA had no significant effect on hepatocytes in Fas-L(-) cocultures. TUDCA, 50 micromol/L (P <.001) and TCDCA up to 200 micromol/L (P <.0001) also reduced the hepatocytes apoptotic rate in Fas-L(-) cocultures. Bile acids did not affect Fas-L expression in fibroblasts or Fas trimerization. FITC-UDCA colocalized with the mitochondrial probe. In conclusion, UDCA, TUDCA, and TCDCA but not TCA are capable of protecting hepatocytes from Fas-L-induced apoptosis. This protective effect is not associated with reductions in Fas trimerization, but may be related to a direct effect on the mitochondrial membrane.

Topics: 3T3 Cells; Animals; Apoptosis; Cells, Cultured; Coculture Techniques; Cross-Linking Reagents; Deoxycholic Acid; Fas Ligand Protein; fas Receptor; Fibroblasts; Fluorescent Dyes; Hepatocytes; In Situ Nick-End Labeling; Kinetics; Membrane Glycoproteins; Mice; Taurochenodeoxycholic Acid; Ursodeoxycholic Acid

Mitochondria have been implicated in the cytotoxicity of amyloid beta-peptide (A beta), which accumulates as senile plaques in the brain of Alzheimer's disease patients. Tauroursodeoxycholate (TUDC) modulates cell death, in part, by preventing mitochondrial membrane perturbation. Using electron paramagnetic resonance spectroscopy analysis of isolated mitochondria, we tested the hypothesis that A beta acts locally in mitochondrial membranes to induce oxidative injury, leading to increased membrane permeability and subsequent release of caspase-activating factors. Further, we intended to determine the role of TUDC at preventing A beta-induced mitochondrial membrane dysfunction. The results demonstrate oxidative injury of mitochondrial membranes during exposure to A beta and reveal profound structural changes, including modified membrane lipid polarity and disrupted protein mobility. Cytochrome c is released from the intermembrane space of mitochondria as a consequence of increased membrane permeability. TUDC, but not cyclosporine A, almost completely abrogated A beta-induced perturbation of mitochondrial membrane structure. We conclude that A beta directly induces cytochrome c release from mitochondria through a mechanism that is accompanied by profound effects on mitochondrial membrane redox status, lipid polarity, and protein order. TUDC can directly suppress A beta-induced disruption of the mitochondrial membrane structure, suggesting a neuroprotective role for this bile salt.

Topics: Amyloid beta-Peptides; Animals; Cytochrome c Group; Electron Spin Resonance Spectroscopy; Intracellular Membranes; Membrane Lipids; Membrane Proteins; Mitochondria; Mitochondria, Liver; Oxidative Stress; Peptide Fragments; Permeability; Rats; Rats, Wistar; Spin Labels; Taurochenodeoxycholic Acid

Whether bile acids regulate biliary epithelial cell (BEC) secretory functions in human is poorly known. The purpose of the study was to determine if human gallbladder-derived BEC exhibit bile acid transport activity that affect their secretory functions and to evaluate the influence of bile acid hydrophobicity in this response by comparing the effects of tauroursodeoxycholate (TUDC) and of taurochenodeoxycholate (TCDC). Expression of the apical sodium-dependent bile acid transporter (ASBT) and of the organic anion transporting polypeptide (OATP-A) was detected and associated with sodium-dependent and sodium-independent [(3)H]taurocholate uptake in BEC. Sodium-dependent uptake (K(m), 66 +/- 2.5 micromol/L; Vmax, 39.4 +/- 4.6 pmol/mg protein/min) was significantly higher than sodium-independent uptake. TCDC stimulated Cl(-) efflux and mucin secretion in cultured cells, and both effects were sodium-dependent. Both TCDC and TUDC were efficiently transported in BEC, as assessed by competitive uptake experiments. However, as compared with TCDC, TUDC induced significantly lower mucin secretion whereas there was no significant difference between TCDC- and TUDC-induced chloride efflux. Protein kinase C down-regulation caused a 70% reduction in TUDC-induced mucin secretion, but did not affect TCDC-induced secretion, which was mediated predominantly by Ca(2+)/calmodulin-dependent protein kinase II activation. These results provide evidence that bile acids may be transported mainly via ASBT in human gallbladder BEC and stimulate hydroelectrolytic and mucin secretion in these cells. Individual bile acids activate different signaling pathways leading to a different balance between mucin and chloride secretion. The differential effect of TUDC may cause a reduction in bile inspissation and provide a benefit in biliary disorders.

Topics: Bile Ducts; Carrier Proteins; Cells, Cultured; Chlorides; Cholagogues and Choleretics; Epithelial Cells; Humans; Hydroxysteroid Dehydrogenases; Membrane Glycoproteins; Mucins; Protein Kinase C; Taurochenodeoxycholic Acid

S-adenosyl-L-methionine (SAMe) and tauroursodeoxycholate (TUDC) exert an additive ameliorating effect on taurolithocholate (TLC)-induced cholestasis. The aims were to investigate the protective effect of SAMe on 17beta-estradiol-glucuronide (17betaEG) cholestasis and to find out whether SAMe and TUDC may exert an additive, ameliorating effect.. Hepatocyte couplet function was assessed by canalicular vacuolar accumulation (cVA) of cholyllysylfluorescein (CLF). Cells were co-treated with 17betaEG and SAMe, TUDC, or both (protection study), or treated with 17betaEG and then with SAMe, TUDC or both (reversion study) before CLF uptake. Couplets were also co-treated with SAMe and dehydroepiandrosterone (DHEA), a competitive substrate for the sulfotransferase involved in 17betaEG detoxification. The effects of 17betaEG, SAMe and TUDC were also examined on intracellular distribution of F-actin.. Both SAMe and TUDC significantly protected against, and reversed, 17betaEG-induced cholestasis, but their effects were not additive. DHEA abolished the protective effect of SAMe. 17BetaEG did not affect the uptake of CLF into hepatocytes at the concentrations used, and also, it did not affect the intracellular distribution of F-actin.. 17BetaEG does not affect the uptake of CLF into hepatocytes. SAMe and TUDC protect and reverse 17betaEG-induced cholestasis, but without an additive effect. Protection by SAMe may involve facilitating the sulfation of 17betaEG.

Topics: Actins; Animals; Biological Transport, Active; Cholestasis; Cholic Acids; Dehydroepiandrosterone; Estradiol; Fluoresceins; Hepatocytes; In Vitro Techniques; Male; Rats; Rats, Wistar; S-Adenosylmethionine; Taurochenodeoxycholic Acid

Ursodeoxycholic acid (UDCA) exerts anticholestatic effects by undefined mechanisms. Previous work suggested that UDCA stimulates biliary exocytosis via Ca(++)- and protein kinase C (PKC)-dependent mechanisms. Therefore, the effect of taurine-conjugated UDCA (TUDCA) was studied in the experimental model of taurolithocholic acid (TLCA)-induced cholestasis on bile flow, hepatobiliary exocytosis, distribution of PKC isoforms, and density of the apical conjugate export pump, Mrp2, in canalicular membranes. Isolated perfused rat livers were preloaded with horseradish peroxidase (HRP), a marker of vesicular exocytosis, and were perfused with bile acids or dimethylsulfoxide (control) only. PKC isoform distribution and membrane density of Mrp2 were studied using immunoblotting and immunoelectron-microscopic techniques. Biliary secretion of the Mrp2 substrate, 2,4-dinitrophenyl-S-glutathione (GS-DNP), was studied in the presence or absence of the PKC inhibitor, bisindolylmaleimide I (BIM-I; 1 micromol/L). TLCA (10 micromol/L) impaired bile flow by 51%; biliary secretion of HRP and GS-DNP by 46% and 95%, respectively; membrane binding of the Ca(++)-sensitive alpha-isoform of PKC by 32%; and density of Mrp2 in the canalicular membrane by 79%. TUDCA (25 micromol/L) reversed the effects of TLCA on bile flow, secretion of HRP and GS-DNP, and distribution of alpha-PKC. TUDCA reduced membrane binding of epsilon-PKC and increased Mrp2 density 4-fold in canalicular membranes of cholestatic hepatocytes. BIM-I inhibited the effect of TUDCA on GS-DNP secretion in cholestatic livers by 49% without affecting secretion in controls. In conclusion, TUDCA may enhance the secretory capacity of cholestatic hepatocytes by stimulation of exocytosis and insertion of transport proteins into apical membranes via PKC-dependent mechanisms.

Topics: Animals; Anions; Bile; Bile Canaliculi; Cell Membrane; Cholagogues and Choleretics; Cholestasis; Glutathione; Horseradish Peroxidase; Isoenzymes; L-Lactate Dehydrogenase; Male; Membranes; Microscopy, Immunoelectron; Mitochondrial Proteins; Protein Kinase C; Rats; Rats, Sprague-Dawley; Ribosomal Proteins; Saccharomyces cerevisiae Proteins; Taurochenodeoxycholic Acid; Tissue Distribution

Ischemia-reperfusion injury is a major cause of early graft dysfunction after liver transplantation. Tauroursodeoxycholic acid (TUDCA), a natural amidated hydrophilic bile salt, protects from cholestasis and hepatocellular damage in a variety of experimental models, as well as from ischemia-reperfusion injury. We investigated in the human liver transplantation setting the effect of the addition of TUDCA at time of liver harvesting and cold storage on the intra- and postoperative enzyme release and liver histopathology at the end of cold storage, at reperfusion, and 7 days after transplantation.. Eighteen patients undergoing elective liver transplantation were studied, including 6 serving as controls. In six patients, TUDCA was added to the University of Wisconsin solution used during harvesting and cold storage, to reach final concentrations of 2 mM. In three of these patients, TUDCA (3 g) was infused in the portal vein of the donor before organ explantation; in the other three cases, TUDCA was given through both routes.. The use of TUDCA did not cause adverse events. The release of aspartate aminotransferase in the inferior vena cava blood during liver flushing was significantly lower (P=0.05) in TUDCA-treated than in control grafts, as were cytolytic enzyme levels in peripheral blood during the first postoperative week (P<0.02). At electron microscopy, an overt endothelial damage (cytoplasmic vacuolization, cell leakage, and destruction with exposure of hepatocytes to the sinusoidal lumen) was invariably found in control grafts, both at reperfusion and at day 7 after transplant. These features were significantly ameliorated by TUDCA (P<0.001). Several ultrastructural cytoplasmic abnormalities of hepatocytes were seen. Among these, damage to mitochondria matrix and crystae was significantly reduced in TUDCA-treated versus control grafts (P<0.01). Mild to severe damage of bile canaliculi was a constant feature in control biopsies, with dilatation of canalicular lumen and loss of microvilli. Both these abnormalities were markedly ameliorated (P<0.001 by TUDCA). The best preservation was observed when TUDCA was given through both routes.. The use of TUDCA during harvesting and cold storage of human liver is associated with significant protection from ischemia-reperfusion injury. The clinical significance of this findings must be studied.

Topics: Adenosine; Adult; Allopurinol; Biopsy; Cold Temperature; Female; Glutathione; Hepatocytes; Humans; Insulin; Liver; Liver Transplantation; Male; Microscopy, Electron; Middle Aged; Organ Preservation; Organ Preservation Solutions; Pilot Projects; Postoperative Care; Protective Agents; Raffinose; Reperfusion; Taurochenodeoxycholic Acid; Tissue and Organ Procurement

We investigated the therapeutic effect of tauroursodeoxycholate on phalloidin-induced cholestasis in rats. Intrahepatic cholestasis was induced by administration of phalloidin (500 microg/kg, i.p.) for 7 days. From the day of the last phalloidin injection, tauroursodeoxycholate (60-360 micromol/kg) was given intravenously twice a day for 4 days. On the next day after the last tauroursodeoxycholate administration, bile flow, serum biochemical parameters and biliary lipid excretion rates were determined. Tauroursodeoxycholate significantly suppressed the decrease in bile flow and increases in serum alkaline phosphatase, leucine aminopeptidase and glutamic pyruvic transaminase activities, cholesterol, phospholipid and bile acid concentrations observed in phalloidin-induced cholestasis in rats. Furthermore, tauroursodeoxycholate significantly improved the biliary cholesterol and phospholipid excretion rates in phalloidin-induced cholestasis in rats. These results demonstrate the usefulness of tauroursodeoxycholate as a therapeutic agent in intrahepatic cholestasis.

Topics: Alanine Transaminase; Alkaline Phosphatase; Animals; Aspartate Aminotransferases; Bile; Bile Acids and Salts; Biliary Tract; Bilirubin; Cholestasis, Intrahepatic; Cholesterol; Dose-Response Relationship, Drug; Leucyl Aminopeptidase; Male; Phalloidine; Phospholipids; Rats; Rats, Wistar; Taurochenodeoxycholic Acid

Topics: Apoptosis; Cryopreservation; Humans; Liver Transplantation; Reperfusion Injury; Taurochenodeoxycholic Acid

Ursodeoxycholic acid (UDCA) is a bile acid (BA) used for cholesterol gallstone dissolution. Since epidemiological evidence indicates that BAs can be involved in the etiology of colorectal cancer, we investigated the effects of UDCA and its physiologically produced taurine conjugate tauroursodeoxycholic acid (TUDCA) on human lymphocyte cultures in terms of genetic damage in the form of micronuclei (MN) production, cell cycle modifications and induction of apoptosis. With respect to controls, treatment with UDCA (from 10 microg/ml) caused a dose-related increase in MN, whereas TUDCA caused no significant increase (up to 1000 microg/ml). Fluorescence in situ hybridization (FISH) analysis using pancentromeric probes suggested that UDCA exerts aneugenic activity. Bromodeoxyuridine/Hoechst flow cytometry showed that both BA significantly inhibit cell cycle progression (UDCA at 100 microg/ml, and TUDCA, more markedly at 300-1000 microg/ml). Neither UDCA nor TUDCA affected induction of apoptosis, as evaluated by the Annexin-V-Fluos assay. We conclude that UDCA is potentially genotoxic. However, taking into account the characteristics of other physiological BA, our findings are in line with the concept that long-term UDCA treatment may be safely administered. The multi-assay approach reported here could be useful in the toxicological evaluation of newly developed BA analogs as candidates for pharmacological use.

Topics: Apoptosis; Biomarkers; Bromodeoxyuridine; Cell Cycle; Cells, Cultured; Cholagogues and Choleretics; Dose-Response Relationship, Drug; Flow Cytometry; Humans; In Situ Hybridization, Fluorescence; Lymphocytes; Male; Micronucleus Tests; Mutagens; Taurochenodeoxycholic Acid; Time Factors; Ursodeoxycholic Acid

Cholesterol in human bile is solubilized in micelles by (relatively hydrophobic) bile salts and phosphatidylcholine (unsaturated acyl chains at sn-2 position). Hydrophilic tauroursodeoxycholate, dipalmitoyl phosphatidylcholine, and sphingomyelin all decrease cholesterol crystal-containing zones in the equilibrium ternary phase diagram (van Erpecum, K. J., and M. C. Carey. 1997. Biochim. Biophys. Acta. 1345: 269-282) and thus could be valuable in gallstone prevention. We have now compared crystallization in cholesterol-supersaturated model systems (3.6 g/dl, 37 degrees C) composed of various bile salts as well as egg yolk phosphatidylcholine (unsaturated acyl chains at sn-2 position), dipalmitoyl phosphatidylcholine, or sphingomyelin throughout the phase diagram. At low phospholipid contents [left two-phase (micelle plus crystal-containing) zone], tauroursodeoxycholate, dipalmitoyl phosphatidylcholine, and sphingomyelin all enhanced crystallization. At pathophysiologically relevant intermediate phospholipid contents [central three-phase (micelle plus vesicle plus crystal-containing) zone], tauroursodeoxycholate inhibited, but dipalmitoyl phosphatidylcholine and sphingomyelin enhanced, crystallization. Also, during 10 days of incubation, there was a strong decrease in vesicular cholesterol contents and vesicular cholesterol-to-phospholipid ratios (approximately 1 on day 10), coinciding with a strong increase in crystal mass. At high phospholipid contents [right two-phase (micelle plus vesicle-containing) zone], vesicles were always unsaturated and crystallization did not occur. Strategies aiming to increase amounts of hydrophilic bile salts may be preferable to increasing saturated phospholipids in bile, because the latter may enhance crystallization.

Topics: 1,2-Dipalmitoylphosphatidylcholine; Bile; Bile Acids and Salts; Cholesterol; Crystallization; Humans; Micelles; Models, Biological; Phosphatidylcholines; Phospholipids; Sphingomyelins; Taurochenodeoxycholic Acid

Bile acids are known to have damaging as well as protective effects on liver cells. A likely candidate for bile acid-mediated hepatocellular injury during cholestasis is glycochenodeoxycholic acid (GCDCA), a hydrophobic bile acid with a direct cytotoxic effect on hepatocytes. In contrast, ursodeoxycholic acid was shown to exhibit protective effects. Our aim was to determine the effect of GCDCA on proliferation, synthesis and secretion of proteins and death processes in cultured rat hepatocytes. Furthermore, it should be studied whether the hydrophilic bile acid tauroursodeoxycholic acid (TUDCA) might be able to protect cells from the damaging effect of GCDCA. Our results demonstrate that GCDCA decreased dose-dependently hepatocellular proliferation, synthesis and secretion of newly synthesized proteins and, at low concentration, induced apoptosis or, at high doses, cytolysis of cultured hepatocytes. TUDCA did not exert cytotoxic effects on the isolated hepatocytes at a wide range of concentrations. However, TUDCA coincubated with GCDCA protected the cells from the damaging effect of GCDCA at all measured parameters except the secretion of newly synthesized protein.

Topics: Animals; Apoptosis; Cell Division; Cells, Cultured; DNA; DNA Fragmentation; Dose-Response Relationship, Drug; Drug Antagonism; Glycochenodeoxycholic Acid; Hepatocytes; L-Lactate Dehydrogenase; Male; Protein Biosynthesis; Rats; Rats, Wistar; Taurochenodeoxycholic Acid; Ursodeoxycholic Acid

ATP receptors are ubiquitously expressed and are potential targets for the therapy of a number of disorders. However, delivery of ATP or other nucleotides to specific tissues is problematic, and no pharmacological means to stimulate the release of endogenous ATP has been described. We examined the effects of the bile acid ursodeoxycholic acid (UDCA) on ATP release into bile, since this bile acid is the only agent known to be of therapeutic benefit in secretory disorders of the liver, and since its mechanism of action is not established. Both UDCA and its taurine conjugate stimulated secretion of ATP by isolated rat hepatocytes, and produced measurable increases in ATP in bile of isolated rat liver. Perfusion of ATP into microdissected bile-duct segments induced Ca(2+) signalling in bile-duct epithelia, while perfusion of bile acid did not. Thus UDCA may promote bile flow by inducing hepatocytes to release ATP into bile, which then stimulates fluid and electrolyte secretion by bile-duct epithelia downstream via changes in cytosolic Ca(2+). Moreover, these findings demonstrate the feasibility of using pharmacological means to induce secretion of endogenous ATP. Since the liver and other epithelial organs express luminal ATP receptors, these findings more generally suggest that a mechanism exists for pharmacological activation of this paracrine signalling pathway. This strategy may be useful for treatment of cystic fibrosis and other secretory disorders of the liver and other epithelial tissues.

Topics: Adenosine Triphosphate; Animals; Bile Acids and Salts; Bile Ducts; Calcium; Cells, Cultured; Dose-Response Relationship, Drug; Hepatocytes; Liver; Male; Perfusion; Rats; Rats, Sprague-Dawley; Signal Transduction; Taurochenodeoxycholic Acid; Time Factors; Uridine Triphosphate; Ursodeoxycholic Acid

Canalicular secretion of bile acids is stimulated by tauroursodesoxycholate (TUDC). This study investigates the underlying mechanisms.. TUDC effects on mitogen-activated protein (MAP) kinases, taurocholate (TC) excretion, proteolysis, and the localization of the bile salt export pump (Bsep) were studied in rat hepatocytes and perfused liver.. TUDC induced a transient and concentration-dependent activation of p38(MAPK) and of extracellular signal-regulated kinase 2 (Erk-2), but not of c-Jun-N-terminal kinase (JNK). In perfused liver, TUDC concentrations of 20 micromol/L was sufficient to elicit the MAP kinase responses and TC choleresis. SB 202190, a specific inhibitor of p38(MAPK), had no effect on TUDC- induced Erk activation but abolished the stimulatory effect of TUDC on TC excretion in perfused liver, indicating the requirement of p38(MAPK) in addition to the reported Erk dependence for the choleretic response. TUDC-induced stimulation of TC excretion was accompanied by a p38(MAPK)-dependent insertion of subcanalicular immunoreactive Bsep into the canalicular membrane. In addition TUDC induced a p38(MAPK)-sensitive inhibition of proteolysis.. TUDC-induced stimulation of canalicular TC excretion involves a MAP kinase-dependent translocation of subcanalicular Bsep to the canalicular membrane. Dual activation of Erks and p38(MAPK) is required for the choleretic effect of both TUDC and hypo-osmotic cell swelling.

Topics: Animals; Cells, Cultured; Cholagogues and Choleretics; Enzyme Activation; Enzyme Inhibitors; Hepatocytes; Imidazoles; Liver; Male; Mitogen-Activated Protein Kinase 1; Mitogen-Activated Protein Kinase 8; Mitogen-Activated Protein Kinases; Osmolar Concentration; p38 Mitogen-Activated Protein Kinases; Pyridines; Rats; Rats, Wistar; Taurochenodeoxycholic Acid; Taurocholic Acid

There is currently no effective treatment for Huntington's disease (HD), a progressive, fatal, neurodegenerative disorder characterized by motor and cognitive deterioration. It is well established that HD is associated with perturbation of mitochondrial energy metabolism. Tauroursodeoxycholic acid (TUDCA), a naturally occurring bile acid, can stabilize the mitochondrial membrane, inhibit the mitochondrial permeability transition, decrease free radical formation, and derail apoptotic pathways. Here we report that TUDCA significantly reduced 3-nitropropionic acid (3-NP)-mediated striatal neuronal cell death in cell culture. In addition, rats treated with TUDCA exhibited an 80% reduction in apoptosis and in lesion volumes associated with 3-NP administration. Moreover, rats which received a combination of TUDCA + 3-NP exhibited sensorimotor and cognitive task performance that was indistinguishable from that of controls, and this effect persisted at least 6 months. Bile acids have traditionally been used as therapeutic agents for certain liver diseases. This is the first demonstration, however, that a bile acid can be delivered to the brain and function as a neuroprotectant and thus may offer potential therapeutic benefit in the treatment of certain neurodegenerative diseases.

Topics: Animals; Cell Death; Cells, Cultured; Cognition; Corpus Striatum; Disease Models, Animal; Female; Huntington Disease; Mitochondria; Motor Activity; Nerve Degeneration; Neurotoxins; Nitro Compounds; Propionates; Rats; Rats, Inbred F344; Taurochenodeoxycholic Acid

Mitochondrial glutathione (GSH) plays a key role against tumor necrosis factor alpha (TNF)-induced apoptosis because its depletion is known to sensitize hepatocytes to TNF. The present study examined the role of tauroursodeoxycholic acid (TUDCA) administration to chronic ethanol-fed rats on mitochondrial GSH levels and kinetics, mitochondrial membrane physical properties, TNF-induced peroxide formation, and subsequent hepatocyte survival. TUDCA selectively increased the levels of GSH in mitochondria without an effect on cytosolic GSH. This outcome was accompanied by improved initial rate of GSH transport examined at low (1 mmol/L) and high (10 mmol/L) GSH concentrations both in intact mitochondria and mitoplasts prepared from ethanol-fed livers. Assessment of membrane fluidity revealed an increased order parameter in mitochondria and mitoplasts from ethanol-fed rats compared with pair-fed controls, which was prevented by TUDCA administration. Compared with hepatocytes from pair-fed rats, TNF stimulated peroxide generation in hepatocytes from ethanol-fed rats, preceding TNF-induced cell death. Administration of TUDCA to ethanol-fed rats prevented TNF-induced peroxide formation and cell death, an effect that was reversed on depletion of the recovered mitochondrial GSH levels by (R,S)-3-hydroxy-4-pentenoate before TNF treatment. The protective effect of TUDCA against TNF was not because of activation of phosphatidylinositol 3-kinase, discarding a role for a survival-dependent pathway. Thus, these findings reveal a novel role of TUDCA in protecting hepatocytes in long-term ethanol-fed rats through modulation of mitochondrial membrane fluidity and subsequent normalization of mitochondrial GSH levels.

Topics: Animals; Biological Transport; Cell Death; Drug Synergism; Enzyme Activation; Ethanol; Glutathione; Hepatocytes; Male; Mitochondria, Liver; Pentanoic Acids; Phosphatidylinositol 3-Kinases; Rats; Rats, Sprague-Dawley; Taurochenodeoxycholic Acid; Tumor Necrosis Factor-alpha

Tauroursodeoxycholic acid (TUDC) is a hydrophilic bile acid that has a cytoprotective effect in primary biliary cirrhosis and primary sclerosing cholangitis. TUDC also protects hepatocytes from hydrophobic bile acid-induced apoptosis. The aim of this study was to determine whether TUDC ameliorates hepatocyte apoptosis during ischemia-reperfusion injury.. We used a rat model of hepatic warm ischemia-reperfusion injury to assess the effects of TUDC. Male Sprague-Dawley rats were subjected to 1 or 2 hr of normothermic ischemia followed by 3 or 6 hr of reperfusion. The treatment group received TUDC (50 mg/kg) by bolus intravenous injection 30 min before initiation of ischemia, whereas the control group received saline only. Blood samples for biochemical analysis were obtained after 6 hr of reperfusion. Liver biopsies for histological assessment were obtained 3 and 6 hr after reperfusion. Hepatocyte apoptosis was determined by terminal dUTP nick-end labeling. The pro-apoptotic protein Bax was quantified at the mRNA and protein level.. Treatment with TUDC significantly reduced serum transaminase levels. This was associated with a significant amelioration in the levels of hepatocyte apoptosis in the TUDC-treated group compared with control. Furthermore, Western blot analysis of Bax expression in liver tissue indicated that TUDC inhibited the translocation of Bax from the cytosol to the mitochondria.. TUDC significantly reduced hepatic injury in this model. The beneficial effects of TUDC upon hepatocyte apoptosis were related to the modulation of Bax protein translocation.

Topics: Animals; Aspartate Aminotransferases; bcl-2-Associated X Protein; Biological Transport; Blotting, Western; Cytoprotection; Gene Expression; In Situ Nick-End Labeling; Ischemia; Liver; Liver Circulation; Male; Mitochondria, Liver; Proto-Oncogene Proteins; Proto-Oncogene Proteins c-bcl-2; Rats; Rats, Sprague-Dawley; Reperfusion Injury; Taurochenodeoxycholic Acid

The aim of this study was to examine whether tauroursodeoxycholate (TUDC) and cholestyramine resin (CR) enhance biliary carcinogenesis in the hamster model. A cholecystoduodenostomy with dissection of the extrahepatic bile duct on the distal end of the common duct was performed on Syrian hamsters. The hamsters were then divided randomly into 3 groups: control group, TUDC-treated group, and CR-treated group. All animals received N-nitrosobis(2-oxopropyl)amine (BOP) to initiate pancreaticobiliary cancer. The experiment was terminated at week 16 and the number of neoplastic lesions was counted microscopically. In the TUDC group, the intrahepatic biliary carcinogenesis was more accelerated than that observed in the control group, but no promoting effect was seen in the pancreas, gallbladder, or extrahepatic bile duct. In the CR group, both the intrahepatic biliary and the gallbladder carcinogenesis were inhibited compared with that observed in the control group and the TUDC group. TUDC enhanced the intrahepatic bile duct carcinogenesis, whereas CR inhibited both the intrahepatic bile duct and the gallbladder carcinoma. Bile acids were suggested to promote biliary carcinoma in the hamster model.

Topics: Administration, Oral; Animals; Anion Exchange Resins; Biliary Tract Neoplasms; Carcinogens; Cholagogues and Choleretics; Cholestyramine Resin; Cricetinae; Drug Synergism; Female; Isomerism; Mesocricetus; Nitrosamines; Pancreatic Neoplasms; Taurochenodeoxycholic Acid; Time Factors

The accumulation of endogenous bile acids contributes to hepatocellular damage during cholestatic liver disease. To evaluate the potential role of apoptotic cell death due to increased concentrations of bile acids, primary human hepatocytes were treated with hydrophobic and hydrophilic bile acids. Because the Fas receptor-ligand system may mediate apoptosis in human liver cells, the effect of toxic bile acids on hepatocellular Fas receptor expression was evaluated.. Primary human hepatocytes were incubated with 50 and 100 microM glycochenodeoxycholic acid (GCDCA) and co-incubated with equimolar concentrations of tauroursodeoxycholic acid (TUDCA). To evaluate cytolytic and apoptotic effects, morphological alterations, hepatocellular enzyme release, nuclear DNA fragmentation and hepatocellular Fas receptor expression were evaluated.. Apoptotic cell death was significantly increased after exposure to 50 microM GCDCA. Bile acid-induced apoptosis was not accompanied by hepatocellular Fas receptor overexpression. Tauroursodeoxycholic acid reduced apoptosis, as indicated by a significant reduction of oligonucleosomal DNA cleavage. Fas receptor expression was not significantly affected by tauroursodeoxycholic acid. At higher concentrations, direct cytolytic cell destruction was observed.. Primary human hepatocytes represent a suitable model to study bile acid-induced apoptotic cell death. In these hepatocytes, already low bile acid concentrations might induce apoptotic cell death, which is not triggered by hepatocellular Fas receptor overexpression. Apoptotic DNA fragmentation was significantly reduced by co-incubation with tauroursodeoxycholic acid. The reduction of bile acid-induced apoptosis by ursodeoxycholic acid and its conjugates may contribute to the beneficial effects of these hydrophilic bile acids used for medical treatment of several cholestatic liver diseases.

Topics: Apoptosis; Aspartate Aminotransferases; Bile Acids and Salts; Cells, Cultured; DNA Fragmentation; fas Receptor; Humans; In Situ Nick-End Labeling; Liver; Taurochenodeoxycholic Acid

Ursodesoxycholic acid, widely used for the treatment of cholestatic liver disease, causes choleretic, anti-apoptotic and immunomodulatory effects. Here the effects on choleresis of its taurine conjugate tauroursodesoxycholate (TUDC), which is present in the enterohepatic circulation, were correlated with the activation of important elements of intracellular signal transduction in cultured rat hepatocytes and perfused rat liver. TUDC induced a time- and concentration-dependent activation of the small GTP-binding protein Ras and of phosphoinositide 3-kinase (PI 3-kinase) in cultured hepatocytes. Ras activation was dependent on PI 3-kinase activity, without the involvement of protein kinase C- and genistein-sensitive tyrosine kinases. Ras activation by TUDC was followed by an activation of the mitogen-activated protein kinases extracellular-signal-regulated kinase-1 (Erk-1) and Erk-2. In perfused rat liver, PI 3-kinase inhibitors largely abolished the stimulatory effect of TUDC on taurocholate excretion, suggesting an important role for a PI 3-kinase/Ras/Erk pathway in the choleretic effect of TUDC.

Topics: Animals; Bile Acids and Salts; Cells, Cultured; Hepatocytes; Male; Phosphatidylinositol 3-Kinases; ras Proteins; Rats; Rats, Wistar; Signal Transduction; Taurochenodeoxycholic Acid

Ursodeoxycholic acid (UDCA) has been shown to be a strong modulator of the apoptotic threshold in both hepatic and nonhepatic cells. 3-Nitropropionic acid (3-NP), an irreversible inhibitor of succinate dehydrogenase, appears to cause apoptotic neuronal cell death in the striatum, reminiscent of the neurochemical and anatomical changes associated with Huntington's disease (HD). This study was undertaken (a) to characterize further the mechanism by which 3-NP induces apoptosis in rat neuronal RN33B cells and (b) to determine if and how the taurine-conjugated UDCA, tauroursodeoxycholic acid (TUDCA), inhibits apoptosis induced by 3-NP. Our results indicate that coincubation of cells with TUDCA and 3-NP was associated with an approximately 80% reduction in apoptosis (p < 0.001), whereas neither taurine nor cyclosporin A, a potent inhibitor of the mitochondrial permeability transition (MPT), inhibited cell death. Moreover, TUDCA, as well as UDCA and its glycine-conjugated form, glycoursodeoxycholic acid, prevented mitochondrial release of cytochrome c (p < 0.001), which probably accounts for the observed inhibition of DEVD-specific caspase activity and poly(ADP-ribose) polymerase cleavage. 3-NP decreased mitochondrial transmembrane potential (p < 0.001) and increased mitochondrial-associated Bax protein levels (p < 0.001). Coincubation with TUDCA was associated with significant inhibition of these mitochondrial membrane alterations (p < 0.01). The results suggest that TUDCA inhibits 3-NP-induced apoptosis via direct inhibition of mitochondrial depolarization and outer membrane disruption, together with modulation of Bax translocation from cytosol to mitochondria. In addition, cell death by 3-NP apparently occurs through pathways that are independent of the MPT.

Topics: Animals; Apoptosis; bcl-2-Associated X Protein; Caspases; Cells, Cultured; Cytochrome c Group; Hepatocytes; Huntington Disease; Intracellular Membranes; Mitochondria; Mitochondrial Swelling; Neurons; Nitro Compounds; Permeability; Poly(ADP-ribose) Polymerases; Propionates; Proto-Oncogene Proteins; Proto-Oncogene Proteins c-bcl-2; Rats; Reactive Oxygen Species; Taurochenodeoxycholic Acid; Ursodeoxycholic Acid

Ursodeoxycholic acid has been widely used as a therapeutic agent in cholesterol gallstones and liver disease patients, but its mechanism of action is still under investigation.. The protective effect of ursodeoxycholic acid, both free, taurine and glycine conjugated, against hepatotoxic bile acids such as chenodeoxycholic acid and its taurine amidate was studied in bile fistula rats and compared with the cholic and taurocholic acid effect.. Tauroursodeoxycholic acid, glycine ursodeoxycholic acid, ursodeoxycholic acid, taurocholic acid and cholic acid were infused iv over 1 hour (8 micromol/min/kg) together with an equimolar dose of either taurochenodeoxycholic acid or chenodeoxycholc acid. Bile flow, total and individual bile acid and biliary lactate dehydrogenase and alkaline phosphatase enzymes were measured.. Taurochenodeoxycholic acid and chenodeoxycholc acid caused cholestasis and liver damage associated with a decreased bile flow, total and individual bile acids secretion accompanied by a biliary leakage of lactate dehydrogenase and alkaline phosphatase enzymes. Tauroursodeoxycholic acid, glycine ursodeoxycholic acid, ursodeoxycholic acid and taurocholic acid, on the contrary, were choleretic, inducing an opposite effect on biliary parameters. Simultaneous infusion of taurochenodeoxycholic acid and the protective bile acid resulted in a functional and morphological improvement of the above parameters in the following order: glycine ursodeoxycholic acid > tauroursodeoxycholic acid > ursodeoxycholic acid followed by taurocholic acid; cholic acid was ineffective.. The results show the protective effect of glycine ursodeoxycholic acid, ursodeoxycholic acid and tauroursodeoxycholic acid. This may be due to a facilitated transport of the toxic bile acid into bile; conjugation with taurine is less effective than glycine. Finally, the better protective effect of ursodeoxycholic acid and its amidates with respect to cholic acid and its taurine conjugated form seems to be related to their different lipophilicity and micellar forming capacity.

Topics: Alkaline Phosphatase; Animals; Bile Acids and Salts; Carrier Proteins; Chenodeoxycholic Acid; Humans; Hydroxysteroid Dehydrogenases; L-Lactate Dehydrogenase; Liver; Liver Diseases; Male; Membrane Glycoproteins; Rats; Rats, Sprague-Dawley; Taurochenodeoxycholic Acid; Ursodeoxycholic Acid

The rat liver organic anion transporting polypeptide (Oatp1) has been extensively characterized mainly in the Xenopus laevis expression system as a polyspecific carrier transporting organic anions (bile salts), neutral compounds, and even organic cations. In this study, we extended this characterization using a mammalian expression system and confirm the basolateral hepatic expression of Oatp1 with a new antibody. Besides sulfobromophthalein [Michaelis-Menten constant (Km) of approximately 3 microM], taurocholate (Km of approximately 32 microM), and estradiol- 17beta-glucuronide (Km of approximately 4 microM), substrates previously shown to be transported by Oatp1 in transfected HeLa cells, we determined the kinetic parameters for cholate (Km of approximately 54 microM), glycocholate (Km of approximately 54 microM), estrone-3-sulfate (Km of approximately 11 microM), CRC-220 (Km of approximately 57 microM), ouabain (Km of approximately 3,000 microM), and ochratoxin A (Km of approximately 29 microM) in stably transfected Chinese hamster ovary (CHO) cells. In addition, three new substrates, taurochenodeoxycholate (Km of approximately 7 microM), tauroursodeoxycholate (Km of approximately 13 microM), and dehydroepiandrosterone sulfate (Km of approximately 5 microM), were also investigated. The results establish the polyspecific nature of Oatp1 in a mammalian expression system and definitely identify conjugated dihydroxy bile salts and steroid conjugates as high-affinity endogenous substrates of Oatp1.

Topics: Animals; Anion Transport Proteins; Carrier Proteins; CHO Cells; Cholic Acid; Cricetinae; Dehydroepiandrosterone Sulfate; Dipeptides; Estradiol; Estrone; Glycocholic Acid; HeLa Cells; Humans; Kinetics; Liver; Ochratoxins; Ouabain; Piperidines; Rats; Recombinant Proteins; Substrate Specificity; Sulfobromophthalein; Taurochenodeoxycholic Acid; Taurocholic Acid; Transfection; Xenopus laevis

We recently reported that bile salts play a role in the regulation of mucin secretion by cultured dog gallbladder epithelial cells. In this study we have examined whether bile salts also influence mucin secretion by the human epithelial colon cell line LS174T. Solutions of bile salts were applied to monolayers of LS174T cells. Mucin secretion was quantified by measuring the secretion of [3H]GlcNAc labeled glycoproteins. Both unconjugated bile salts as well as taurine conjugated bile salts stimulated mucin secretion by the colon cells in a dose-dependent fashion. Hydrophobic bile salts were more potent stimulators than hydrophilic bile salts. Free (unconjugated) bile salts were more stimulatory compared with their taurine conjugated counterparts. Stimulation of mucin secretion by LS174T cells was found to occur at much lower bile salt concentrations than in the experiments with the dog gallbladder epithelial cells. The protein kinase C activators PMA and PDB had no stimulatory effect on mucin secretion. We conclude that mucin secretion by the human colon epithelial cell line LS174T is regulated by bile salts. We suggest that regulation of mucin secretion by bile salts might be a common mechanism, by which different epithelia protect themselves against the detergent action of bile salts, to which they are exposed throughout the gastrointestinal tract.

Topics: Adenocarcinoma; Animals; Bile Acids and Salts; Colon; Colonic Neoplasms; Dogs; Enzyme Activation; Epithelium; Humans; Mucins; Phorbol 12,13-Dibutyrate; Protein Kinase C; Solutions; Structure-Activity Relationship; Taurochenodeoxycholic Acid; Tetradecanoylphorbol Acetate; Tritium; Tumor Cells, Cultured

The monohydroxy bile acid, taurolithocholate (TLC), causes cholestasis in vivo and in isolated perfused livers. It is also cholestatic in vitro and, in this study using isolated rat hepatocyte couplets, causes a reduction of the accumulation of (fluorescent) bile acid in the canalicular vacuoles (cVA) of this polarized cell preparation. The hepatoprotective bile acid, tauroursodeoxycholate (TUDCA), partially protects against the action of TLC when added at the same time. It also partially reverses the cholestatic effect if added after the cells have been exposed to TLC. A second hepatoprotective compound, S-adenosyl-L-methionine (SAMe) also not only partially protects against the action of TLC when added at the same time, but it too is able to partially reverse the cholestatic effect. Neither hepatoprotective agent is fully effective alone, but their effects are additive. In combination, a full restoration of cVA is observed in moderate cholestasis, but not in severe cholestasis. We discuss briefly some possible mechanisms involved in the additive mode of action of both hepatoprotective compounds. In summary, we show for the first time that SAMe and TUDCA can exert an additive effect in the amelioration of TLC-induced cholestasis in isolated rat hepatocyte couplets. This finding may be of possible clinical relevance.

Topics: Animals; Bile Acids and Salts; Bile Canaliculi; Cholestasis; Fluorescent Dyes; Male; Rats; Rats, Wistar; S-Adenosylmethionine; Taurochenodeoxycholic Acid; Taurolithocholic Acid; Vacuoles

Bile salts regulate the subselection of phosphatidylcholine species secreted into bile and thereby modulate bile metastability. The aim of this study was to determine whether bile salts alter phosphatidylcholine species of the canalicular membrane, and if they do, to clarify whether the cytoprotective action of hydrophilic bile salts is associated with modulation of phosphatidylcholine composition in cell membrane bilayers. Bile salt-pool-depleted rats were infused intravenously with sodium taurocholate at a constant rate (200 nmol/min/100 g body wt) for 2 hr, followed by infusion of either sodium tauroursodeoxycholate, sodium tauroalphamuricholate, or sodium taurobetamuricholate (200 nmol/min/100 g) for 2 hr. Biliary outputs of cholesterol and phosphatidylcholine and phosphatidylcholine hydrophobicity in bile and subcellular fractions were determined. The cytoprotective action of hydrophilic bile salts was determined by the release of canalicular membrane-localizing enzymes (alkaline phosphatase, leucine aminopeptidase) into bile. Tauroursodeoxycholate, taurobetamuricholate, and tauroalphamuricholate decreased the release of these enzymes when compared to values under taurocholate infusion. Bile phosphatidylcholine hydrophobicity was also decreased by the bile salts, whereas the cholesterol/phosphatidylcholine ratio was increased. In contrast, phosphatidylcholine hydrophobicity in the canalicular membrane was increased by these three bile salts. In conclusion, hydrophilic bile salts promote biliary secretion of relatively hydrophilic phosphatidylcholine secretion into bile, and consequently phosphatidylcholine hydrophobicity in canalicular membranes increased. Such an alteration in phosphatidylcholine species within canalicular membrane enhances its lateral packing density with less fluidity, and this may account, in part, for the cytoprotective action of hydrophilic bile salts against hydrophobic bile salts.

Topics: Animals; Bile Acids and Salts; In Vitro Techniques; Liver; Male; Membrane Fluidity; Phosphatidylcholines; Rats; Rats, Sprague-Dawley; Taurochenodeoxycholic Acid; Taurocholic Acid

Adult pairs of Schistosoma mansoni were kept in culture in the presence or absence of various bile salts and the numbers of parasite eggs deposited in vitro were monitored for 2 weeks. The hydrophilic bile salt tauroursodeoxycholic acid (TUDCA) was found to produce a highly significant increase in the number of eggs deposited during the 1st week of culture. The hydrophobic bile salt taurochenodeoxycholic acid (TCDCA) and the intermediately hydrophobic salt taurocholate (TCA) produced more moderate increases. These results expand previous data showing that schistosomes kept in the presence of portal blood have higher oviposition rates than schistosomes kept in systemic blood.

Topics: Animals; Bile Acids and Salts; Culture Media; Female; Mice; Oviposition; Parasite Egg Count; Schistosoma mansoni; Taurochenodeoxycholic Acid; Taurocholic Acid

Ursodeoxycholic acid is used in the treatment of acute and chronic intrahepatic cholestasis because it ameliorates cholestasis and protects hepatocytes. However, few studies have examined the effect of bile acids on the function of Kupffer cells.. The effect of various bile acids on cultured rat Kupffer cells was studied in terms of phagocytic activity in response to latex particles and morphological alterations. Video-enhanced differential interference contrast microscopy was used.. Taurochenodeoxycholic acid and taurodeoxycholic acid reduced the number of latex particles incorporated into Kupffer cells, but taurocholic and tauroursodeoxycholic acids enhanced phagocytosis of latex particles. Inhibition of phagocytosis by taurochenodeoxycholic acid or taurodeoxycholic acid was essentially dose dependent. Tauroursodeoxycholic acid also enhanced phagocytosis by Kupffer cells in which phagocytosis had been reduced by pretreatment with taurochenodeoxycholic acid or taurodeoxycholic acid. Incorporated latex particles had a distinct translocation speed of 0.084+/-0.024 microm/s (mean maximum speed+/-SD); the speed was in the same range with tauroursodeoxycholic acid treatment. Tauroursodeoxycholic acid induced a 56% expansion of cytoplasm, associated with increased ruffling and movement of intracellular organelles.. These observations suggest that tauroursodeoxycholic acid enhances membrane trafficking without changing translocation speed.

Topics: Animals; Cells, Cultured; Kupffer Cells; Male; Microscopy, Interference; Microscopy, Video; Microspheres; Phagocytosis; Rats; Rats, Sprague-Dawley; Taurine; Taurochenodeoxycholic Acid; Taurodeoxycholic Acid; Ursodeoxycholic Acid

Tauroursodeoxycholate (TUDC) is used routinely in the treatment of cholestatic liver disease. The present study was designed to determine whether it would mitigate ischemia/reperfusion injury in an in vivo pig liver-transplantation model.. Transplantation was performed in 12 animals after a preservation time of 8 h. In the control group (n=6), 0.9% saline was infused into the donor. In the experimental group (n=6), TUDC was given intravenously at a rate of 2 micromol/kg body weight per minute. In the recipient, infusion was started at the time of reperfusion; saline was infused for 400 min in the control group, TUDC for the same duration at a rate of 0.2 micromol/kg body weight per minute in the experimental group. Blood was drawn for determination of liver enzymes. Bile samples were collected and bile flow (BF) and bile salt secretion rate (BSSR) were determined.. One-week survival was 92% and not different among groups. Liver enzymes were lower in the TUDC group than the saline group. Prior to TUDC infusion in the donor animals, there were no differences in BF and BSSR. After infusion of TUDC, BF and BSSR were highly significantly different than the control group.. Infusion of TUDC in pig livers protects against ischemia/reperfusion injury in vivo. This might be due to the membrane-stabilizing effect of TUDC. Preconditioning of liver grafts with TUDC could potentially lead to improved liver function post-transplantation.

Topics: Analysis of Variance; Animals; Bile Acids and Salts; Cholagogues and Choleretics; Infusions, Intravenous; Liver; Liver Transplantation; Male; Organ Preservation; Reperfusion Injury; Swine; Taurochenodeoxycholic Acid

Reperfusion injury is a serious problem after clinical liver transplantation, often leading to dys- or even non-function of grafts. The present study was designed to determine whether the hydrophilic bile salt tauroursodeoxycholate (TUDC), known to be hepatoprotective in cholestatic liver disease, mitigates reperfusion injury in an in vivo pig liver transplantation model. Liver transplantation was performed in 12 pigs after a preservation time of 8 h. TUDC was administered to donor and recipient animals, and saline to controls. Blood was drawn at different time points for determination of liver enzymes. Bile samples were collected, and bile flow (BF), and bile salt secretion rate (BSSR) determined. Samples of liver tissue and bile ducts were taken for assessment by light and electron microscopy. Liver enzymes were significantly lower in the TUDC group. BF and BSSR were significantly higher. Microscopy revealed better preservation of bile duct architecture of the TUDC-infused animals. We can conclude that infusions of TUDC in pig livers ameliorate reperfusion injury in vivo. The molecular basis for this finding may be the membrane stabilizing effect of TUDC. Further studies are warranted to clarify its effect.

Topics: Animals; Cholagogues and Choleretics; Cyclosporine; Immunosuppressive Agents; Liver; Liver Function Tests; Liver Transplantation; Male; Postoperative Complications; Reperfusion Injury; Swine; Taurochenodeoxycholic Acid

The prevention of the hepatotoxic effects produced by intravenous infusion of taurochenodeoxycholic acid (TCDCA) by coinfusion with taurohyodeoxycholic acid (THDCA) was evaluated in bile fistula rats; the hepatoprotective effects of the latter were also compared with those of tauroursodeoxycholic acid (TUDCA). Rats infused with TCDCA at a dose of 8 micromol/min/kg showed reduced bile flow and calcium secretion, as well as increased biliary release of alkaline phosphatase (AP) and lactate dehydrogenase (LDH). This was associated with a very low biliary secretion rate of TCDCA (approximately 1 micromol/min/kg). Simultaneous infusion of THDCA or TUDCA at the same dose preserved bile flow and almost totally abolished the pathological leakage of the two enzymes into bile. The effect was slightly more potent for THDCA. The maximum secretion rate of TCDCA increased to the highest value (8 micromol/min/kg) when coinfused with either of the two hepatoprotective bile acids (BA), which were efficiently and completely secreted in the bile, without metabolism. Calcium output was also restored and phospholipid (PL) secretion increased with respect to the control saline infusion. This increase was higher in the THDCA study. These data show that THDCA is highly effective in the prevention of hepatotoxicity induced by intravenous infusion of TCDCA by facilitating its biliary secretion and reducing its hepatic residence time; this was associated with selective stimulation of PL biliary secretion.

Topics: Alkaline Phosphatase; Animals; Calcium; Cholagogues and Choleretics; Cholestasis; Injections, Intravenous; L-Lactate Dehydrogenase; Liver; Phospholipids; Rats; Taurochenodeoxycholic Acid; Taurocholic Acid; Taurodeoxycholic Acid

Ethanol impairs cellular antioxidant defense and protein metabolism. Hydrophilic bile acids are protective against ethanol-induced cytotoxicity. This study investigated the compartmentation of intracellular thiol and protein redox status after acute ethanol intoxication in the liver and the effect of tauroursodeoxycholate pretreatment.. The concentrations of total glutathione, glutathione bound to proteins, sulfhydryl proteins, carbonyl proteins and malondialdehyde were measured in hepatic cytosol, mitochondria and nuclei after oral administration of 25% ethanol (4 g/kg) or isocaloric carbohydrate solution to rats. The metabolisms of ethanol and acetaldehyde were investigated by giving 4-methylpyrazole (1 mmol/kg i.p.) or cyanamide (15 mg/kg i.p.) 1 h prior to ethanol ingestion. One group of rats received tauroursodeoxycholate (12 mg/kg p.os) 1 h before ethanol ingestion.. Ethanol significantly decreased the glutathione concentrations. Significant increases in glutathione bound to proteins, carbonyl protein and malondialdehyde concentrations were also noted, especially at the mitochondrial level. Enhanced carbonyl protein formation was also observed (p < 0.01). The inhibition of acetaldehyde metabolism, but not ethanol metabolism, exaggerated the alterations produced by ethanol. Pretreatment with tauroursodeoxycholate significantly reduced lipid and protein oxidation, particularly in mitochondria. By contrast, no changes were observed in glutathione content and compartmentation.. Ethanol intoxication differentially impairs thiol and protein redox status in the subcellular fractions of rat liver. These alterations seem dependent on acetaldehyde rather than ethanol. Tauroursodeoxycholate administration protects proteins and lipids from ethanol-induced oxidative damage without influencing the glutathione content and compartmentation.

Topics: Acetaldehyde; Alcohol Drinking; Animals; Cell Nucleus; Cyanamide; Cytosol; Ethanol; Fomepizole; Glutathione; Kinetics; Liver; Male; Malondialdehyde; Mitochondria, Liver; Oxidation-Reduction; Proteins; Pyrazoles; Rats; Rats, Sprague-Dawley; Sulfhydryl Compounds; Taurochenodeoxycholic Acid

In cholestatic liver disease, bile acids may initiate or aggravate hepatocellular damage. Cellular necrosis and cell death may be due to detergent effects of bile acids, but apoptosis may also play a role. In cholestasis, the conditions determining either apoptotic or cytolytic cell death are still unclear. Primary rat hepatocytes in culture represent a suitable model to study bile-acid-induced liver damage.. Glycochenodeoxycholic acid, a hydrophobic bile acid, was used to induce cell damage. Tauroursodeoxycholic acid, a hydrophilic bile acid, served as substrate to study possible protective effects of such compounds. To study the time and concentration dependency of bile-acid-induced cytolysis and apoptosis, morphologic alterations, hepatocellular enzyme release and nucleosomal DNA fragmentation were evaluated.. Bile-acid-induced cytolysis, as indicated by hepatocellular enzyme release and by morphologic signs of membrane destruction, increased with concentration and time. Addition of tauroursodeoxycholic acid to the incubation medium reduced cytolysis significantly, indicating a direct hepatoprotective effect of this bile acid against the detergent action of hydrophobic bile acids. In contrast to cytolysis, apoptosis with DNA fragmentation was induced by low concentrations of glycochenodeoxycholic acid a few hours after incubation. Coincubation with tauroursodeoxycholic acid in equimolar concentrations significantly reduced apoptosis, indicating another direct hepatoprotective effect of tauroursodeoxycholic acid.. It seems likely that in severe cholestasis, bile-acid-induced injury of hepatocytes is due mainly to cytolysis, whereas in moderately severe cholestasis apoptosis represents the predominant mechanism of bile acid toxicity. Tauroursodeoxycholic acid may reduce both bile-acid-induced apoptosis and cytolysis.

Topics: Animals; Apoptosis; Aspartate Aminotransferases; Bile Acids and Salts; Cell Death; Cells, Cultured; DNA Fragmentation; Glycochenodeoxycholic Acid; L-Lactate Dehydrogenase; Liver; Male; Necrosis; Rats; Rats, Wistar; Taurochenodeoxycholic Acid

1. Bile salts stimulate mucin secretion by the gallbladder epithelium. We have investigated whether this stimulatory effect is due to a detergent effect of bile salts. 2. The bile salts taurocholic acid (TC) and tauroursodeoxycholic acid (TUDC) and the detergents Triton X-100 (12.5-400 microM) and Tween-20 (0.1-3.2 mM) were applied to monolayers of cultured dog gallbladder epithelial cells. Mucin secretion was studied by measuring the secretion of [3H]N-acetyl-d-glucosamine-labelled glycoproteins. We also attempted to alter the fluidity of the apical membrane of the cells through extraction of cholesterol with beta-cyclodextrin (2.5-15 mM). The effect on TUDC-induced mucin secretion was studied. Cell viability was assessed by measuring lactate dehydrogenase (LDH) leakage or 51Cr release. 3. In contrast with the bile salts, the detergents were not able to cause an increase in mucin secretion without causing concomitant cell lysis. Concentrations of detergent that increased mucin release (>100 microM Triton X-100, >0.8 mM Tween-20), caused increased LDH release. Incubation with beta-cyclodextrin resulted in effective extraction of cholesterol without causing an increase in 51Cr release. However, no effect of the presumed altered membrane fluidity on TUDC (10 mM)-induced mucin secretion was observed. 4. The stimulatory effect of bile salts on mucin secretion by gallbladder epithelial cells is not affected by the fluidity of the apical membrane of the cells and also cannot be mimicked by other detergents. We conclude that the ability of bile salts to cause mucin secretion by the gallbladder epithelium is not determined by their detergent properties.

Topics: Animals; beta-Cyclodextrins; Bile Acids and Salts; Cells, Cultured; Cholesterol; Cyclodextrins; Detergents; Dogs; Gallbladder; Glycoproteins; Membrane Fluidity; Mucins; Octoxynol; Polysorbates; Taurochenodeoxycholic Acid; Taurocholic Acid

The toxic effect of hydrophobic bile acids is claimed to be in part mediated by lipid peroxidation. Conversely, antioxidant properties of tauroursodeoxycholic acid (TUDC), a hydrophilic bile acid, have been suggested as a possible mechanism by which TUDC confers its beneficial effect in a variety of diseases. We have investigated the effect of taurodeoxycholic acid (TDC), a hydrophobic bile acid and TUDC on lipid peroxidation using a pure lipid system both in the presence and absence of iron ions. Neither TDC nor TUDC showed any effect on spontaneous lipid peroxidation of phosphatidylcholine liposomes or sodium arachidonate solution. This lack of effect excludes the possibility of direct prooxidant or antioxidant properties for TDC and TUDC. Addition of ferrous ions (0.1 mM) to the lipid system brought about a linear increase in lipid peroxidation with time. The presence of TDC caused an increase in the rate and extent of iron-stimulated lipid peroxidation. The propensity of bile acids to increase iron-induced lipid peroxidation was related to hydrophobicity of the individual bile acids, with the highest effect observed with taurolithocholic acid, whereas TUDC did not have any influence. The TDC-induced increase in the iron-stimulated lipid peroxidation was concentration dependent. Addition of TUDC (10 mM) completely abolished the effect of TDC (2 mM) on iron-induced lipid peroxidation. This finding suggests that TUDC does not function as an antioxidant per se but may prevent lipid peroxidation caused by TDC. In conclusion, only in the presence of iron ions, hydrophobic bile acids may enhance lipid peroxidation. TUDC has no antioxidant activity per se but may counter the TDC-induced increase in iron-stimulated lipid peroxidation.

Topics: Arachidonic Acid; Bile Acids and Salts; Ferric Compounds; Ferrous Compounds; Iron; Lipid Peroxidation; Liposomes; Membrane Lipids; Phosphatidylcholines; Solutions; Taurochenodeoxycholic Acid; Taurodeoxycholic Acid; Time Factors

The regulation of cAMP synthesis by hormones and bile acids is altered in isolated hamster hepatocytes 2 days after bile duct ligation (BDL) [Y. Matsuzaki, B. Bouscarel, M. Le, S. Ceryak, T. W. Gettys, J. Shoda, and H. Fromm. Am. J. Physiol. 273 (Gastrointest. Liver Physiol. 36): G164-G174, 1997]. Therefore, studies were undertaken to elucidate the mechanism(s) responsible for this impaired modulation of cAMP formation. Hepatocytes were isolated 48 h after either a sham operation or BDL. Both preparations were equally devoid of cholangiocyte contamination. Although the basal cAMP level was not affected after BDL, the ability of glucagon to maximally stimulate cAMP synthesis was decreased by approximately 40%. This decreased glucagon effect after BDL was not due to alteration of the total glucagon receptor expression. However, this effect was associated with a parallel 50% decreased expression of the small stimulatory G protein alpha-subunit (GsalphaS). The expression of either the large subunit (GsalphaL) or the common beta-subunit remained unchanged. The expression of Gialpha2 and Gialpha3 was also decreased by 25 and 46%, respectively, and was associated with the failure of ANG II to inhibit stimulated cAMP formation. Therefore, alterations of the expression of GsalphaS and Galphai are, at least in part, responsible for the attenuated hormonal regulation of cAMP synthesis. Because cAMP has been reported to stimulate both bile acid uptake and secretion, impairment of cAMP synthesis and bile acid uptake may represent an initial hepatocellular defense mechanism during cholestasis.

Topics: Angiotensin II; Animals; Cholestasis; Colforsin; Common Bile Duct; Cricetinae; Cyclic AMP; Glucagon; GTP-Binding Protein alpha Subunits, Gi-Go; GTP-Binding Protein alpha Subunits, Gs; GTP-Binding Proteins; Keratins; Ligation; Liver; Male; Mesocricetus; Receptors, Glucagon; Taurochenodeoxycholic Acid; Ursodeoxycholic Acid

S-adenosylmethionine (SAMe) increases survival in alcoholic liver cirrhosis and may have a beneficial effect in cholestatic liver disease. SAMe repletes glutathione stores and protects tissue from oxygen free radicals. The effect of SAMe on bile acid-induced apoptosis is unknown. In the present study the possible hepatoprotective effect of SAMe was evaluated and compared with that of tauroursodeoxycholic acid (TUDCA).. Primary rat hepatocytes treated with glycochenodeoxycholic acid (GCDCA) were used as a model for cholestasis-induced hepatocellular damage, which served to study the effects of SAMe and TUDCA on bile acid-induced apoptosis and cytolysis.. SAMe reduced bile acid-induced apoptosis but did not prevent bile acid-induced cytolysis. Compared with SAMe, TUDCA was more efficient in reducing apoptosis due to toxic bile acids. The combination of SAMe and TUDCA had additive effects in reducing apoptosis.. The reduction in bile acid-induced apoptosis by SAMe may represent one of the factors responsible for its beneficial effects in the treatment of liver diseases.

Topics: Animals; Apoptosis; Bile Acids and Salts; Cell Nucleus; Cell Survival; Cells, Cultured; DNA Fragmentation; Dose-Response Relationship, Drug; Liver; Male; Rats; Rats, Wistar; S-Adenosylmethionine; Taurochenodeoxycholic Acid

Tauroursodeoxycholic acid (TUDC) is one of the most hydrophilic taurin conjugated bile acids. TUDC has a suppressive effect on DNA synthesis in primary cultured rat hepatocytes. In this study, we investigated the growth inhibitory effect of TUDC on cultured human keratinocytes. TUDC suppressed the proliferation of keratinocytes in a dose dependent fashion, as measured by both cell counts and 5-bromo-2'-deoxyuridine (BrdU) uptake. Keratinocytes reproliferated and reached almost the same cell number as control after removal of TUDC from the medium. TUDC (1 mM) had no effect on the cell viability, as measured by the dye exclusion test. Epidermal sheets stratified in the presence of TUDC appeared thinner than those stratified without TUDC. These results suggest that TUDC has a reversible growth suppressive effect on human keratinocytes through the mechanism other than cytotoxicity and would be applicable for the treatment of hyperproliferative skin disorders such as psoriasis.

Topics: Animals; Cell Division; Cells, Cultured; DNA Replication; Humans; Keratinocytes; Rats; Taurochenodeoxycholic Acid

This study assessed the ability of ursodeoxycholic acid (UDCA) and one of its metabolites, tauroursodeoxycholic acid (TUDCA), to inhibit platelet derived growth factor (PDGF) stimulated fibroproliferation and compared these results to the effect of pentoxifylline and its metabolite-1 [1-(5-hydroxyhexyl)-3,7-dimethylxanthine] and assessed the potential role of cyclic AMP in this process. Fibroproliferative activity was measured by the tritiated thymidine uptake assay in human fibroblast cultures. All four compounds: pentoxifylline, metabolite-1, UDCA and TUDCA inhibited the fibroproliferative activity stimulated by PDGF (8 ng/ml). Incubation of fibroblasts with dibutyryl cyclic AMP reduced proliferation stimulated by PDGF suggesting that the PDGF stimulated proliferation was sensitive to inhibition by a membrane permeable analogue of cyclic AMP. Incubation of myofibroblasts with dibutyryl cyclic AMP significantly inhibited PDGF stimulated proliferation suggesting that cyclic AMP can regulate PDGF stimulated proliferation in the myofibroblast. To determine if the effect of pentoxifylline on fibroproliferation was mediated by cyclic AMP, we used dideoxyadenosine, a potent inhibitor of adenylyl cyclase. The effect of pentoxifylline on fibroproliferation was not prevented by dideoxyadenosine, which inhibits formation of cyclic AMP, thus suggesting that the inhibitory effect of pentoxifylline on PDGF-stimulated proliferation of fibroblasts was not mediated by cyclic AMP, arguing against a role for cyclic AMP in this process. Combinations of UDCA (250 microM) plus pentoxifylline (120 microM) or UDCA (250 microM) plus TUDCA (250 microM) inhibited fibroproliferative activity stimulated by PDGF to a greater extent than either drug alone. As UDCA has been reported to decrease cyclic AMP these results argue against a role for cyclic AMP in this process. Finally the results suggest that UDCA may inhibit PDGF-stimulated proliferation via an inhibition of C-kinase.

Topics: 1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine; Antimetabolites; Bucladesine; Cell Division; Cells, Cultured; Cholagogues and Choleretics; Cyclic AMP; Dideoxyadenosine; Drug Interactions; Enzyme Inhibitors; Fibroblasts; Humans; Pentoxifylline; Platelet-Derived Growth Factor; Stimulation, Chemical; Taurochenodeoxycholic Acid; Tetrazolium Salts; Thiazoles; Ursodeoxycholic Acid

Tauroursodeoxycholic acid (TUDCA) is of potential benefit in cholestatic disorders. However, the effect of TUDCA on hepatic ischemia-reperfusion injury is unknown. We studied this subject with particular regard to its roles in hepatic calcium mobilization. Three doses of TUDCA were used with continuous intravenous infusion (1.0, 0.1, and 0.01 micromol/kg body weight/min). At 3 hr after 1 hr of ischemia and reperfusion in 70% rat liver, high-dose TUDCA reduced hepatic reperfused injury according to biochemical and histological findings and significantly increased bile flow after reperfusion. It significantly increased tissue calcium content and serum calcium concentration after reperfusion. Furthermore, it also enhanced biliary calcium concentration and total output during reperfusion. In conclusion, TUDCA has a salutary effect on ischemia-reperfusion injury of the liver. However, it is still unclear how the calcium mobilization induced by TUDCA is associated with the hepatoprotection against ischemia-reperfusion injury.

Topics: Animals; Bile; Calcium; Cholestasis; Liver; Liver Diseases; Male; Peroxidase; Rats; Rats, Sprague-Dawley; Reperfusion Injury; Taurochenodeoxycholic Acid

Bile acids exert cellular and molecular effects in the liver, but little is known about tissue concentrations. The aim of this study was to characterize bile acid composition in human and rat liver tissue and hepatocyte nuclei and examine the effects of experimental cholestasis and bile acid administration.. Bile acids were measured by gas chromatography-mass spectrometry.. Liver tissue concentrations of sham-operated rats were 130.8 +/- 21.3 nmol/g, representing 2%-4% of the bile acid pool; cholic and delta 22-beta-muricholic acids were the major bile acids identified. Concentrations increased 7-8-fold with bile duct ligation; deoxycholate and hyodeoxycholate disappeared. Lithocholate concentrations were higher in ligated rats (6.4 +/- 0.4 vs. 3.9 +/- 0.5 nmol/g for sham-operated). Total bile acid concentrations in human liver tissue were 61.6 +/- 29.7 nmol/g and comprised mainly chenodeoxycholic and cholic acids. Concentrations were higher during ursodeoxycholate or tauroursodeoxycholate administration (157.2 +/- 45.6 and 161.6 +/- 43.4 nmol/g, respectively), and liver tissue was enriched 30% in ursodeoxycholate at the expense of hydrophobic bile acids. Bile acids were identified in rat hepatic nuclei (50-110 pmol/4 x 10(7) nuclei), accounting for < 0.1% of liver tissue levels.. Human and rat liver tissue bile acid concentrations are low, increase with bile acid administration or bile duct ligation, and account for only a small fraction of the bile acid pool.

Topics: Adult; Animals; Bile Acids and Salts; Cell Nucleus; Cholestasis; Humans; Liver; Male; Middle Aged; Rats; Rats, Sprague-Dawley; Taurochenodeoxycholic Acid; Ursodeoxycholic Acid

Topics: Bile; Bile Acids and Salts; Cholecystectomy; Gallbladder; Glycochenodeoxycholic Acid; Glycodeoxycholic Acid; Humans; Hydrogen; Magnetic Resonance Spectroscopy; Micelles; Phospholipids; Taurochenodeoxycholic Acid; Taurocholic Acid; Ursodeoxycholic Acid

The hepatic transport of bile salts can be regulated by changes in bile salt pool size and/or in the flux of bile salts through the liver. Prolonged bile salt pool depletion is associated with down-regulation of maximum taurocholate transport and decreased canalicular membrane specific bile salt binding sites. This study was undertaken to investigate: a) whether adaptive down-regulation of maximum hepatic bile salt transport occurs to the same extent for bile acids of different hydrophobicity; and b) the role of microtubule-dependent vesicular pathway in the adaptive changes of bile salt transport capacity.. Male rats were subjected to 24-h or 48-h external biliary diversion to induce bile salt pool depletion. Basal bile flow, bile salt secretion and lipid secretion, maximum secretory rate of three bile salts of different hydrophobicity (tauroursodeoxycholate, taurocholate and taurochenodeoxycholate) and changes in the biliary excretion of two markers of the microtubule-dependent vesicular pathway (horseradish peroxidase and polyethyleneglycol molecular weight-900) were measured in control and bile salt-depleted rats. Taurocholate-stimulated horseradish peroxidase biliary excretion was also assessed in order to define whether the restoration of bile salt flux across the hepatocytes increased the excretion of this marker in bile salt-depleted rats.. The reduction in the maximum secretory rate of the three bile salts under study observed after prolonged biliary diversion was clearly related to their hydrophobicity, with greater reduction for taurochenodeoxycholate and smaller reduction for tauroursodeoxycholate, compared with taurocholate. The biliary excretion of vesicular transport markers was significantly reduced in bile salt-depleted rats. However, when stimulated by taurocholate, biliary excretion of horseradish peroxidase was similar to controls.. The magnitude of the decrease of the hepatic bile salt maximum transport capacity seen after bile salt pool depletion is directly related to the hydrophobicity of the bile salt infused. A functionally depressed vesicular transport pathway appears to be also a contributing factor to this phenomenon.

Topics: Adaptation, Biological; Animals; Bile Acids and Salts; Biological Transport; Cholagogues and Choleretics; Down-Regulation; Endocytosis; Horseradish Peroxidase; Liver; Male; Microtubules; Organ Size; Polyethylene Glycols; Rats; Rats, Sprague-Dawley; Taurochenodeoxycholic Acid

The effect of tauro-beta-muricholate (beta MC-tau) and tauro-alpha-muricholate (alpha MC-tau) on oestradiol-17 beta-glucuronide (E217G)-induced cholestasis was compared with that of tauroursodeoxycholate (UDC-tau) in rats. Like UDC-tau, alpha MC-tau and beta MC-tau infused at the rate of 0.2 mumol/min per 100 g bodyweight (BW) completely inhibited the cholestasis induced by E217G infused at the rate of 0.06 mumol/min per 100 g BW for 20 min. These findings indicate that beta MC-tau and alpha MC-tau are useful in protecting against various types of experimental cholestasis, as well as against bile acid-induced cholestasis.

Topics: Animals; Cholestasis; Estradiol; Isomerism; Male; Rats; Rats, Sprague-Dawley; Taurochenodeoxycholic Acid; Taurocholic Acid

The mouse mdr2 gene encodes a P-glycoprotein expressed in the canalicular membrane of the hepatocyte. Mice in which this gene has been inactivated (mdr2 -/-) show a defect in biliary phospholipid and cholesterol secretion and develop non-suppurative cholangitis. We hypothesized that secretion of bile salts without lipids initiates this liver disease.. To delineate the pathologic process, mdr2 (-/-) mice were fed different bile salt-supplemented diets for 22 weeks after weaning. Aspects of liver pathology including eosinophilic bodies, portal inflammation, ductular proliferation, mitotic activity and fibrosis were semi-quantitatively scored.. It was observed that liver pathology was more severe in female than in male mice when fed a purified control diet. This correlated with a more hydrophobic bile salt composition of female vs. male bile. When increasing amounts of cholate were added to the diet (0.01% and 0.1%), the secretion of taurocholate increased and this was accompanied by a more severe liver pathology. At the high dose of cholate (0.1%), the bile salt compositions of male and female mice became similar, as did the severity of the histological score. Addition of cholate to the diet did not induce liver pathology in (+/+) mice. Addition of ursodeoxycholate to the diet (0.5%) led to a near complete replacement of biliary bile salts by tauroursodeoxycholate and this reduced pathology and dissipated the difference between males and females.. These observations support our hypothesis that liver pathology in the mdr2 (-/-) mouse is caused by bile salts and depends on the hydrophobicity c.q. cytotoxicity of biliary bile salts.

Topics: Animals; Bile Acids and Salts; Diet; Female; Genes, MDR; Liver Diseases; Male; Mice; Mice, Knockout; Sex Characteristics; Solubility; Taurochenodeoxycholic Acid; Ursodeoxycholic Acid; Water

The liver secretes cholesterol and lecithin in the form of mixed vesicles during the formation of bile. When exposed to bile salts, these metastable vesicles undergo various structural rearrangements. We have examined the effects of three different bile salts, taurocholate (TC), tauroursodeoxycholate (TUDC), and taurodeoxycholate (TDC), on the stability of sonicated lecithin vesicles containing various amounts of cholesterol. Vesicle growth was probed by turbidity measurements, quasi-elastic light scattering, and a resonance energy transfer lipid-mixing assay. Leakage of internal contents was monitored by encapsulation of fluorescence probes in vesicles. At low bile salt-to-lecithin ratios (TC/L or TUDC/L < 1), pure lecithin vesicles do not grow, but exhibit slow intervesicular mixing of lipids as well as gradual leakage. At high BS/L (TC/L or TUDC/L > 5), pure lecithin vesicles are solubilized into mixed micelles with a concomitant decrease in the overall particle size. In this regime, extensive leakage and lipid mixing occur instantaneously after exposure to bile salt. At intermediate BS/L (1 < TC/L or TUDC/L < 5), vesicles grow with time, and the rates of both leakage and lipid mixing are rapid. The data suggest that vesicles grow by the transfer of lecithin and cholesterol via diffusion in the aqueous medium. The addition of cholesterol to lecithin vesicles reduces leakage dramatically and increases the amount of BS required for complete solubilization of vesicles. The more hydrophobic TDC induces vesicle growth at a lower BS/L than does TC or TUDC. These results demonstrate the physiologic forms of lipid microstructures during bile formation and explain how the hydrophilic-hydrophobic balance of BS mixtures may profoundly affect the early stages of CH gallstone formation.

Topics: Bile Acids and Salts; Cholesterol; Lipids; Micelles; Nephelometry and Turbidimetry; Phosphatidylcholines; Structure-Activity Relationship; Taurochenodeoxycholic Acid; Taurocholic Acid

This study aimed to determine the effect in humans of taurohyodeoxycholic acid, a 6alpha-hydroxylated bile acid with hydrophilic properties, on bile lipid secretion. Four cholecystectomized patients who had gallstones and an interrupted enterohepatic circulation were intraduodenally infused with taurohyodeoxycholic and tauroursodeoxycholic acids on separate occasions at a dose of 0.8 to 1 g/h for 3 hours. In hourly bile samples collected for 8 hours after the beginning of the infusion, biliary bile acid composition (by high-performance liquid chromatography), biliary lipid concentrations (by standard methods), and distribution of biliary carriers (by gel chromatography) were evaluated. Blood liver function tests were performed before and after the infusions. Taurohyodeoxycholic and tauroursodeoxycholic acids became the predominant biliary bile acids in all patients except for one infused with taurohyodeoxycholic acid. Taurohyodeoxycholic acid stimulated significantly greater (P < .05) cholesterol and phospholipid secretion per unit of secreted bile acid (0.098 and 0.451 micromol/micromol, respectively) compared with tauroursodeoxycholic acid (0.061 micromol/micromol for cholesterol and 0.275 micromol/micromol for phospholipids). The secretory ratio between phospholipid and cholesterol was significantly higher after infusion of taurohyodeoxycholic acid (3.88 micromol/micromol) compared with taroursodeoxycholic acid (3.09 micromol/micromol) (P < .05). Biliary enrichment with taurohyodeoxycholic acid was positively related with percent concentration of phospholipids but not with that of cholesterol. The opposite trend was observed in tauroursodeoxycholic acid-enriched biles. In both taurohyodeoxycholic acid- and tauroursodeoxycholic acid-rich bile, 80% to 90% of cholesterol was carried in a gel-chromatographic fraction corresponding to an apparent molecular weight of 80 to 200 kd. No alteration in liver function test results was observed after taurohyodeoxycholic acid infusion. In conclusion, taurohyodeoxycholic acid stimulates greater cholesterol and phospholipid secretion than tauroursodeoxycholic acid, but with a higher phospholipid/cholesterol secretory ratio. In bile enriched with both bile acids, biliary cholesterol is transported in non-micellar aggregates. Finally, in the conditions of our study, taurohyodeoxycholic acid was not hepatotoxic.

Topics: Aged; Alkaline Phosphatase; Bile; Bile Acids and Salts; Cholagogues and Choleretics; Female; Humans; Lipid Metabolism; Liver; Liver Function Tests; Male; Taurochenodeoxycholic Acid; Taurodeoxycholic Acid; Transaminases

To investigate the effect of membrane lipid composition on the susceptibility to bile salt damage and protection.. Artificial model cholesterol/phospholipid (c/p) membranes (vesicles) with a varying cholesterol (0-15 mM) and phospholipid content (3-30 mM), and with a c/p ratio ranging up to 1.70, were prepared by sonication. We examined the effect of incubation with increasing concentrations of either tauroursodeoxycholate (TUDC), taurocholate (TC) or taurodeoxycholate (TDC) alone, or with proportionally varying mixtures of TUDC and TDC.. Vesicle integrity was assessed by the change in optical absorbance at 340 nm.. Absorption of the bile salt-vesicle mixture decreased, with increasing bile salt concentration and hydrophobicity: TUDC less than TC less than TDC. Moreover, bile salt-induced damage also depended on membrane composition: vesicles containing more than 5 mM cholesterol and with a c/p ratio greater than 0.8 were less likely to be solubilized by 30 mM bile salt. Similarly, only in cholesterol-rich vesicles (c/p > 0.5) was a protective effect of TUDC against membrane disruption by TDC revealed upon incubation with various TUDC/TDC mixtures.. Apart from the bile salt concentration and hydrophobicity, the cholesterol content of vesicles is pivotal, both in the bile salt-induced solubilization of cholesterol/phospholipid vesicles and in the potency of TUDC to prevent this.

Topics: Bile; Bile Acids and Salts; Cholesterol; Membranes, Artificial; Models, Biological; Phospholipids; Taurochenodeoxycholic Acid; Taurocholic Acid; Taurodeoxycholic Acid; Ultracentrifugation

Colchicine, a microtubule-disrupting agent, induces hepatotoxicity in experimental animals at the doses commonly employed to explore vesicular transport in the liver. The effect of manipulations of the bile salt pool on colchicine-induced hepatotoxicity was studied in rats to determine the role of bile salts in this phenomenon. Leakage of enzyme markers of liver-cell damage into plasma and bile induced by colchicine pre-treatment displayed a sigmoidal log dose-effect curve, the half-maximal effect being reached at 0.12 micromol per 100 g body wt. Lumicolchicine, instead, showed no harmful effect. Maximal increment of biliary LDH discharge induced by colchicine was reduced from 950 +/- 124% to 216 +/- 29% by bile diversion leading to a marked reduction in bile salt output, and this parameter was further decreased to 100 +/- 13% and 157 +/- 39% by subsequent repletion of the bile salt pool with the hydrophilic bile salts taurodehydrocholate and tauroursodeoxycholate, respectively. Conversely, infusion of taurocholate into non-bile salt depleted, colchicine-treated rats led to cholestasis and massive discharge of enzymes into both blood and bile. Our data show conclusively that colchicine-induced hepatotoxicity depends on the magnitude and composition of the bile salt flux traversing the liver. They also support the view that functional integrity of vesicular mechanisms presumably involved in membrane repair are indispensable to protect the hepatocytes from the damaging effect of bile salts during normal bile formation.

Topics: Alkaline Phosphatase; Animals; Bile Acids and Salts; Chromatography, High Pressure Liquid; Colchicine; Dose-Response Relationship, Drug; Gout Suppressants; Isomerism; L-Lactate Dehydrogenase; Liver; Lumicolchicines; Male; Rats; Rats, Wistar; Taurochenodeoxycholic Acid; Taurocholic Acid

Cyclosporin A (CsA) exhibits poor bioavailability after oral administration of Sandimmune, with wide intra- and interindividual variations. Our study sought to determine the effect of the coadministration of CsA standard oily formulation and tauroursodeoxycholate (TUDC) and that of an aqueous micellar solution containing TUDC, monoolein, and CsA in promoting and regulating CsA bioavailability in the rat Pharmacokinetic parameters of CsA were determined in fasted rats after either an intravenous administration (5 mg/kg) or a single oral CsA dose of 10 mg/kg. Compared with oral Sandimmune, the CsA micellar solution significantly improved the CsA bioavailability by 160% and decreased the interindividual variability in bioavailability expressed as percent coefficient of variation from 32% to 15%. The concentration-time profile was modified with a 3.5-fold increase in C(max), a reduction of t(max), and an increased trough concentration. Bioavailability slightly improved in rats receiving standard oily solution plus concomitant TUDC, although not significantly. Data indicate that the structure of the CsA carriers greatly affect drug bioavailability and that aqueous micellar solutions of CsA-TUDC-monoolein constitute efficient vehicles, thus providing for CsA high absorption with low variability.

Topics: Animals; Area Under Curve; Biological Availability; Cyclosporine; Drug Interactions; Half-Life; Male; Micelles; Rats; Rats, Sprague-Dawley; Solutions; Taurochenodeoxycholic Acid

Estradiol-17 beta-D-glucuronide (E-17G), a metabolite of natural estrogen, is well known to cause intrahepatic cholestasis in humans. We therefore investigated the effect of sodium tauroursodeoxycholate (T-UDCA), on E-17G-induced cholestasis in female rats.. For the evaluation of the drug, animals given E-17G (10 mumol/kg) were divided into three groups, and T-UDCA was administered intravenously at various doses after E-17G treatment.. T-UDCA significantly prevented a marked reduction of bile flow in E-17G-treated rats in all experimental schedules. Furthermore, T-UDCA significantly increased in the biliary E-17G excretion rate at an early stage after E-17G treatment in rats. However, this drug caused no significant change in the biliary excretion rate of estradiol-3-sulfate-17 beta-D-glucuronide (E-3S-17G), which is identified as the major biliary metabolite with E-17G throughout the recovery periods.. These results suggest that T-UDCA can improve E-17G induced acute cholestasis by rapidly increasing the biliary E-17G excretion rate. Thus our finding may provide a useful approach for attempts to prevent drug-induced acute cholestasis in humans.

Topics: Animals; Bile; Bile Acids and Salts; Cholestasis; Estradiol; Female; Rats; Rats, Sprague-Dawley; Taurochenodeoxycholic Acid; Ursodeoxycholic Acid

We investigated the effect of sodium tauroursodeoxycholate (UR-906) on cholestasis in common bile duct-ligated rats in comparison with the effect of dehydrocholic acid. UR-906 (30-180 mumol/kg) and dehydrocholic acid (180 mumol/kg) were intravenously given once daily for consecutive 20 days in rats and the common bile duct was ligated for the last 10 days. On the next day after the last test drug administration, serum biochemical and plasma hemostatic variables were determined. UR-906 significantly ameliorated the elevation of serum cholesterol, phospholipid, bilirubin and bile acid concentrations in bile duct-ligated rats. UR-906 significantly suppressed the prolongation of plasma prothrombin time and activated partial thromboplastin time. Furthermore, UR-906 significantly suppressed the decreases in plasma coagulation factor II and X activities. However, dehydrocholic acid did not cause significant changes in any of the variables examined in this model. These results suggest that UR-906 has a beneficial effect against cholestasis induced by bile duct ligation in rats and that this drug may be useful in the treatment of clinical cholestatic disorders.

Topics: Animals; Bile Acids and Salts; Bile Ducts; Bilirubin; Cholagogues and Choleretics; Cholestasis; Cholesterol; Dehydrocholic Acid; Disease Models, Animal; Factor X; Hemostasis; Ligation; Male; Partial Thromboplastin Time; Phospholipids; Prothrombin; Prothrombin Time; Rats; Rats, Wistar; Taurochenodeoxycholic Acid

Tauroursodeoxycholate (TUDCA) is widely used in the treatment of cholestatic liver disease. The purpose of this study was to elucidate molecular mechanisms underlying its beneficial effect.. TUDCA-induced signaling towards bile acid excretion was studied in 24-hour-cultured rat hepatocytes and perfused rat liver.. In rat hepatocytes, TUDCA (> 100 mumol/L) led within 10 minutes to an activation of the mitogen-activated protein (MAP)-kinases extracellular signal-regulated kinase (Erk)-1 and Erk-2. Erk activation by TUDCA was insensitive to inhibition of protein kinase C, tyrosine kinases, and G-protein function. TUDCA-induced Erk activation, however, was abolished in the presence of PD098059, a MAP-kinase kinase (MAP-kinase/Erk-kinase [MEK]) inhibitor and after elevation of intracellular adenosine 3',5'-cyclic monophosphate. Thus, TUDCA signaling towards MAP kinases is different from hypo-osmotic MAP-kinase activation, which is sensitive to inhibitors of tyrosine kinases and G-protein function. Addition of dibutyryl-adenosine 3',5'-cyclic monophosphate or PD098059 also abolished the stimulatory effect of TUDCA (20 mumol/L) on taurocholate excretion in perfused rat liver, whereas tyrosine kinase inhibition was ineffective.. TUDCA signaling towards bile acid secretion is mediated by an Raf/MEK-dependent activation of MAP kinases. Although both TUDCA and hypo-osmotic hepatocyte swelling lead to MAP-kinase activation and a stimulation of bile acid secretion, different upstream signaling events are involved.

Topics: 1-Methyl-3-isobutylxanthine; Animals; Bucladesine; Calcium-Calmodulin-Dependent Protein Kinases; Cells, Cultured; Colforsin; Enzyme Activation; Enzyme Inhibitors; Flavonoids; GTP-Binding Proteins; Indoles; Isomerism; Isoproterenol; Kinetics; Liver; Male; Maleimides; Mitogen-Activated Protein Kinase 1; Mitogen-Activated Protein Kinase 3; Mitogen-Activated Protein Kinases; Models, Biological; Protein Kinase C; Protein-Tyrosine Kinases; Rats; Rats, Wistar; Signal Transduction; Taurochenodeoxycholic Acid; Taurocholic Acid; Tetradecanoylphorbol Acetate

The feedback repression of cholesterol 7alpha-hydroxylase transcriptional activity and mRNA levels by taurocholate (TCA) occurs via a protein kinase C (PKC)-dependent signal. To determine whether bile acids could activate PKC indirectly via generation of diacylglycerol (DG), their effects on DG levels in primary cultures of rat hepatocytes were determined using a DG kinase assay. To determine whether bile acids might activate PKC isozymes more directly, their effects on PKC alpha and delta purified from baculovirus expression systems were examined in phosphatidylserine/phosphatidylcholine/Triton X-100 (PS/PC/TX) mixed micelles. Addition of tauroursodeoxycholate (TUDCA), taurocholate (TCA), or taurodeoxycholate (TDCA) (50 microM) to the cells rapidly (15 min) increased DG content in cultured rat hepatocytes to 105%, 155%, and 130%, respectively, as compared to untreated control cultures. Addition of TCA increased PKC alpha specific activity with EC50 of approximately 400 nM; maximal activity was observed with 5 microM. Other taurine-conjugated bile acids (5 microM) increased PKC alpha specific activity (pmol/min/microg protein) in proportion to their relative hydrophobicity: PS/PC/TX 17 +/- 2; + TUDCA 29 +/- 18; + TCA 68 +/-13; + TDCA 166 +/- 21; and, taurochenodeoxycholate 178 +/- 20 (P vs. PS/PC/TX = 0.54, 0.019, 0.002, and 0.001, respectively); unconjugated bile acids gave similar results (r2 for activity vs. hydrophobicity index 0.59). Taurine-conjugated bile acid interaction enthalpies, as determined by dimyristoyl-phosphatidylcholine chromatography, were more highly correlated (r2 = 0.96) with PKC alpha activation than with the hydrophobicity index. TCA also stimulated the activity of purified PKCdelta with EC50 of approximately 150 nM and maximally (2.7-fold) at 1 microM. Free and taurine-conjugated bile acids (1 microM) increased PKCdelta activity according to their hydrophobicity index (r2 = 0.89) and interaction enthalpies (r2 = 0.96).

Topics: Animals; Baculoviridae; Bile Acids and Salts; Cells, Cultured; Diacylglycerol Kinase; Diglycerides; Enzyme Activation; Isoenzymes; Liposomes; Liver; Phospholipids; Protein Kinase C; Protein Kinase C-alpha; Protein Kinase C-delta; Rats; Recombinant Proteins; Taurochenodeoxycholic Acid; Taurocholic Acid; Taurodeoxycholic Acid

Gallbladder contents from 8 active and 14 dormant black bears were analyzed for individual bile acids by high-performance liquid chromatography and for cholesterol, phospholipids, sodium, potassium, calcium, magnesium, zinc, iron, and copper. Only three bile acids occurring as taurine conjugates were detected: tauroursodeoxycholate, taurochenodeoxycholate, and taurocholate. The proportion of tauroursodeoxycholate to the sum of the three bile acids decreased. Calcium, cholesterol, phospholipids, magnesium, zinc, and copper concentrations were increased in dormancy. Standardized collection and handling procedures yielded more consistent data than previously available. The decrease in tauroursodeoxycholate and absence of deoxycholate and lithocholate are consistent with our working hypothesis that a marked reduction in metabolic activity of the gut flora is an integral part of the adaptation to metabolic stability of the dormant bear.

Topics: Animals; Bile; Bile Acids and Salts; Calcium; Cholesterol; Copper; Gallbladder; Hibernation; Iron; Magnesium; Metals; Phospholipids; Potassium; Seasons; Sodium; Taurochenodeoxycholic Acid; Taurocholic Acid; Ursidae; Zinc

The absorption of ursodeoxycholate and its tauro-conjugate by the jejunum and the terminal ileum of rat intestine was compared with that of other unconjugated bile acids and taurocholate. In the ligated jejunum, the efficacy of absorption of unconjugated bile acids was in the following order: ursodeoxycholate = deoxycholate > chenodeoxycholate = cholate > lithocholate. This order cannot be explained by the theory that the passive diffusion of bile acids is faster the less hydroxyl bonds in the molecule. These findings on the unconjugated bile acids in the ligated jejunum were further confirmed by perfusion experiments. In the ligated terminal ileum, ursodeoxycholate, cholate and deoxycholate were absorbed as fast as taurocholate or tauroursodeoxycholate, whereas absorption of chenodeoxycholate was significantly slower. The Na+-dependency of the absorption of ursodeoxycholate and cholate in the terminal ileum was confirmed by perfusion studies. In conclusion, intestinal absorption of ursodeoxycholate was efficient in both the jejunum and ileum and these results may contribute to the high availability of ursodeoxycholate in various hepatobiliary diseases.

Topics: Animals; Bile Acids and Salts; Ileum; Intestinal Absorption; Jejunum; Ligation; Male; Perfusion; Rats; Rats, Sprague-Dawley; Taurochenodeoxycholic Acid; Time Factors; Ursodeoxycholic Acid

We studied the effect of oral supplementation with ursodeoxycholate (UDCA) or tauroursodeoxycholate (TUDCA) on the lipid content and fatty acid composition of rat hepatic microsomes. UDCA and TUDCA significantly increased the total amount of lipids with the exception of cholesteryl-esters. UDCA significantly increased the triglycerides and phosphatidylethanolamine (PE) microsomal content, and decreased the cholesterol/phospholipids and the phosphatidylcholine (PC)/PE ratio. Both treatments increased the percentage oleic acid and of polyunsaturated fatty acids (PUFA) in each class of lipids. UDCA and TUDCA had a different action on PUFA microsomal molar percentage of phospholipids: UDCA increased the relative percentage of PUFA in the PE fraction, while TUDCA increased the relative percentage of PUFA in the PC fraction. These changes in the hepatic lipid content and composition might in part explain both cytoprotective action of these hydrophillic bile acids and their effect on membrane fluidity.

Topics: Animals; Cholesterol; Fatty Acids; Fatty Acids, Unsaturated; Intracellular Membranes; Isomerism; Male; Membrane Lipids; Microsomes, Liver; Phosphatidylcholines; Phosphatidylethanolamines; Phospholipids; Rats; Rats, Wistar; Taurochenodeoxycholic Acid; Ursodeoxycholic Acid

Ursodeoxycholic acid (UDCA) improves liver function in patients with chronic cholestatic liver diseases by an unknown mechanism. UDCA is conjugated to taurine in vivo, and tauroursodeoxycholic acid (TUDCA) is a potent hepatocellular Ca2+ agonist and stimulates biliary exocytosis and hepatocellular Ca2+ influx, both of which are defective in experimental cholestasis. Protein kinase C (PKC) mediates stimulation of exocytosis in the liver. The aim of this study was to determine the effects of TUDCA on PKC in isolated hepatocytes.. The effect of TUDCA on the distribution of PKC isoenzymes within the hepatocyte was studied using immunoblotting and immunofluorescence techniques. In addition, the effect of TUDCA on the accummulation of sn-1,2-diacylglycerol (DAG), the intracellular activator of PKC, and hepatocellular PKC activity was studied using radioenzymatic techniques.. Immunoblotting studies showed the presence of four isoenzymes (alpha, delta, epsilon, and zeta). The phorbol ester phorbol 12-myristate 13-acetate (1 mumol/L) induced translocation of alpha-PKC, delta-PKC, and epsilon-PKC from cytosol to a particulate membrane fraction, a key step for activation of PKC. TUDCA, but not taurocholic acid, selectively induced translocation of the alpha-PKC isoenzyme from cytosol to the membranes. In addition, TUDCA induced a significant increase in hepatocellular DAG mass and stimulated membrane-associated PKC activity.. TUDCA might stimulate Ca(2+)-dependent hepatocellular exocytosis into bile in part by activation of alpha-PKC.

Topics: Animals; Cell Membrane; Cells, Cultured; Cholagogues and Choleretics; Cytosol; Diglycerides; Enzyme Activation; Exocytosis; Isoenzymes; Liver; Male; Protein Kinase C; Rats; Rats, Sprague-Dawley; Taurochenodeoxycholic Acid; Taurocholic Acid

In this study, the stimulatory effect of bile salts (BS) was evaluated both in vitro, using hepatocyte primary cultures, and in vivo, in normal and 40% partially hepatectomized rats previously fed on BS-enriched diets for 4 weeks. In vitro results show that conjugated cholate (CA) and chenodeoxycholate (CDCA) augmented proliferative activity in rat hepatocytes cultured in absence of mitogens, whereas conjugated deoxycholate (DCA), and ursodeoxycholate (UDCA) did not have any significant effect. None of these BSs increased significantly the replicative response induced by submaximal concentrations of epidermal growth factor (EGF). In vivo, at the end of dietary treatment all animals fed on CA or DCA but not those fed on either CDCA, or UDCA, or tauroursodeoxycholate (TUDCA) developed cholestatic hepatitis and a burst of damage-induced hepatocyte proliferation. After 40% partial hepatectomy (PH), CA- and DCA-treated groups underwent a deterioration of cholestatic hepatitis. On the other hand, in CDCA-, and UDCA-, and TUDCA-treated groups liver histology, serum glutamic pyruvic transaminase (SGPT) and cholestasis indices did not change significantly compared with controls. As far as the proliferative activity, a significant increase was observed not only in CA and DCA but also in UDCA- and TUDCA-fed groups compared with controls, whereas a slight decrease was observed in CDCA-treated animals. In conclusion, our data indicate that conjugated BSs had only a modest stimulatory effect on hepatocyte proliferation in vitro. However, in vivo, in PH rats, UDCA or TUDCA treatment determined a further increase of hepatocellular proliferation not attributable to hepatotoxic effects. Our result suggest that modifications of bile acid pool could modulate hepatocellular proliferation.

Topics: Animals; Bile Acids and Salts; Cell Division; Cells, Cultured; Chenodeoxycholic Acid; Cholic Acid; Cholic Acids; Deoxycholic Acid; Hepatectomy; Liver; Liver Regeneration; Male; Proliferating Cell Nuclear Antigen; Rats; Rats, Inbred F344; Taurochenodeoxycholic Acid; Ursodeoxycholic Acid

Dose-response curves for taurocholate and tauroursodeoxycholate were performed in rat and rabbit livers to get more insight into species differences in the hepatic bile acid uptake. The bile acids showed saturation kinetics in both animals, the Vmax in rat being higher than in rabbit and the Km being lower in the rat than in the rabbit for both the bile acids, with no significant difference in the hepatic cells morphometric parameters. Therefore, it is possible that differences in the kinetic parameters are related to the number and, to a lesser extent, to the affinity of the transporters on the sinusoidal plasma membranes.

Topics: Animals; Bile Acids and Salts; In Vitro Techniques; Liver; Male; Organ Size; Perfusion; Portal Vein; Rabbits; Rats; Rats, Sprague-Dawley; Species Specificity; Taurochenodeoxycholic Acid; Taurocholic Acid

Topics: Animals; Gastric Mucosa; Male; Rats; Rats, Sprague-Dawley; Taurochenodeoxycholic Acid; Taurodeoxycholic Acid

1. Hypersecretion of gallbladder mucin has been proposed to be a pathogenic factor in cholesterol gallstone formation. Using cultured gallbladder epithelial cells, we demonstrated that bile salts regulate mucin secretion by the gallbladder epithelium. In the present study we have investigated whether established second messenger pathways are involved in bile salt-induced mucin secretion. 2. The effect of activators and inhibitors on mucin secretion was studied by measuring the secretion of [3H]N-acetyl-D-glucosamine-labelled glycoproteins. Intracellular cAMP content of the cells was measured using a radioimmunoassay. 3. Incubation of the cells with 10 mM taurocholate did not increase the intracellular cAMP content (25.7 versus control 22.8 pmol of cAMP/mg of protein). No stimulation of mucin secretion was observed after incubation with 1-100 microM concentrations of the calcium ionophores ionomycin and A23187. The stimulatory effect of 10 mM tauroursodeoxycholate (TUDC) on mucin secretion could not be inhibited by the addition of EDTA. Activation of protein kinase C (PKC) by 1 microgram/ml phorbol 12-myristate 13-acetate (PMA) caused an increase in mucin secretion (342% versus control 100%), comparable with the effect of 40 mM TUDC. The effect of 10 ng/ml PMA could partially be inhibited by a concentration of 2 microM of the PKC inhibitor staurosporin. Staurosporin had no inhibitory effect on mucin secretion induced by TUDC. 4. In gallbladder epithelial cells bile salts do not stimulate mucin secretion via one of the classical signal transduction pathways. We hypothesize that bile salts act on mucin secretion via a direct interaction with the apical membrane.

Topics: Acetylglucosamine; Animals; Bile Acids and Salts; Calcimycin; Cells, Cultured; Cyclic AMP; Dinoprostone; Dogs; Edetic Acid; Enzyme Activation; Epithelium; Gallbladder; Ionomycin; Kinetics; Mucins; Phorbol 12,13-Dibutyrate; Protein Kinase C; Second Messenger Systems; Taurochenodeoxycholic Acid; Taurocholic Acid; Tetradecanoylphorbol Acetate; Tritium

Bile salts have been hypothesized to mediate cytotoxicity by increasing membrane permeability to aqueous solutes. We examined whether submicellar bile salt concentrations affect model and native membrane permeability to small uncharged molecules such as water, urea, and ammonia. Osmotic water permeability (Pf) and urea permeability were measured in large unilamellar vesicles composed with egg yolk phosphatidylcholine (EYPC) +/- cholesterol (Ch) or rat liver microsomal membranes by monitoring self-quenching of entrapped carboxyfluorescein (CF). Ammonia permeability was determined utilizing the pH dependence of CF fluorescence. Submicellar bile salt concentrations did not significantly alter Pf of EYPC +/- Ch or rat liver microsomal membranes. At taurodeoxycholate (TDC) or tauroursodeoxycholate concentrations approaching those that solubilized membrane lipids, CF leakage occurred from vesicles, but Pf remained unchanged. Higher bile salt concentrations (0.5-2 mM TDC) did not alter Pf of equimolar EYPC/Ch membranes. The activation energy for transmembrane water flux was unchanged (12.1 +/- 1.2 kcal/mol for EYPC) despite the presence of bile salts in one or both membrane hemileaflets, suggesting strongly that bile salts do not form transmembrane pores that facilitate water flux. Furthermore, submicellar bile salt concentrations did not increase membrane permeability to urea or ammonia. We conclude that at submicellar concentrations, bile salts do not form nonselective convective channels that facilitate transmembrane transport of small uncharged molecules. These results suggest that bile salt-mediated transport of specific substrates, rather than nonselective enhancement of membrane permeability, underlies bile salt cytotoxicity for enterocytes and hepatocytes.

Topics: Ammonia; Animals; Bile Acids and Salts; Calorimetry; Dose-Response Relationship, Drug; Glycodeoxycholic Acid; Intracellular Membranes; Kinetics; Light; Liposomes; Male; Micelles; Microsomes, Liver; Models, Biological; Molecular Weight; Permeability; Phosphatidylcholines; Rats; Rats, Sprague-Dawley; Scattering, Radiation; Solutions; Taurochenodeoxycholic Acid; Taurodeoxycholic Acid; Urea

Tauroursodeoxycholate (TUDC), a relatively hydrophilic bile salt, reduces disruption of cholesterol-rich membranes by more hydrophobic bile salts such as taurocholate (TC), taurochenodeoxycholate (TCDC), or taurodeoxycholate (TDC). We examined the interactions of these bile salts in adsorption to large unilamellar vesicles to determine whether TUDC may stabilize membranes by preventing adsorption of more toxic bile salts. Fractional adsorption was quantified by rapid ultrafiltration. Adsorption coefficient Ai was defined for each bile salt i as ([bound i]/[free i])/[lecithin]. Affinity of different bile salts for lecithin vesicles varied with their relative hydrophobicity, increasing in the order TUDC < TC << TCDC < or = TDC. Ai of each bile salt fell with its accumulation on membranes, reaching a minimum at bound bile salt/lecithin mole ratio (B:L) between 0.05 and 0.1, then increasing with formation of higher-affinity mixed micelles. Inclusion of cholesterol in vesicles reduced Ai of all bile salts. In heterologous binding studies at submicellar concentrations, Ai of each bile salt varied with total B:L but was independent of the specific bile salts present on the membrane. Addition of TUDC to TDC reduced binding of TDC to membranes only slightly and lowered the threshold TDC concentration associated with transition to mixed micelles. However, above this threshold, TUDC markedly altered the adsorption of TDC to lecithin-containing phases. We conclude that TUDC does not directly stabilize membranes; rather, reduced permeabilization and dissolution of cholesterol-rich membranes after addition of TUDC to TDC may result from effects on the formation and structure of simple and mixed micelles.

Topics: Adsorption; Cholesterol; Membrane Lipids; Membranes, Artificial; Micelles; Phosphatidylcholines; Taurochenodeoxycholic Acid; Taurocholic Acid; Taurodeoxycholic Acid

The pathogenesis of hepatic fibrosis in cholestasis is still unknown, except for endotoxaemia. There is a possibility that the elevation of serum bile acids in cholestasis may play an important role in hepatic fibrogenesis due to a reaction to perisinusoidal cells, such as Ito or Kupffer cells. To assess the effects of bile acids, we investigated the cell proliferation and collagen formation of primary cultured Ito cells that were incubated with a Kupffer cell conditioned medium (KCCM) treated with either taurochenodeoxycholic acid (TCDCA) or tauroursodeoxycholic acid (TUDCA) in short-term (8 h) or long-term (48 h) cultures. KCCM treated with TCDCA (100 mumol/L) but not with TUDCA increased cell proliferation of Ito cells in short-term cultures and also partially elevated collagen formation by Ito cells in long-term cultures. The release of tumour necrosis factor-alpha (TNF alpha) from Kupffer cells was increased by TCDCA in short-term cultures, but not in long-term cultures. The release of transforming growth factor-beta 1 (TGF beta 1) from Kupffer cells was increased by TCDCA in long-term cultures, but not in the short-term cultures. TUDCA showed no significant effect on the release of TNF alpha and TGF beta 1 from Kupffer cells. TUDCA or TCDCA itself showed no direct effect on the cell proliferation and collagen formation of Ito cells. In conclusion, these findings are thus considered to show the potentially important role of TCDCA on the development of hepatic fibrosis in the early phase of cholestasis without endotoxaemia.

Topics: Animals; Cell Division; Cells, Cultured; Collagen; Culture Media, Conditioned; Kupffer Cells; Liver; Liver Cirrhosis; Male; Rats; Rats, Wistar; Taurochenodeoxycholic Acid; Time Factors; Transforming Growth Factor beta; Tumor Necrosis Factor-alpha

We have recently shown that taurocholate (TCA) represses the transcriptional activity of cholesterol 7 alpha-hydroxylase, the rate-limiting enzyme of the bile acid biosynthetic pathway, through a protein kinase C (PKC)-dependent mechanism in primary cultures of rat hepatocytes. The present studies sought to determine the mechanisms by which bile acids activate hepatic PKC activity and the consequences of this activation on isoform distribution and cholesterol 7 alpha-hydroxylase mRNA levels. TCA (12.5-100 microM for 15 min) increased membrane-associated "classic" isoenzyme cPKC-alpha and "novel" isoenzymes nPKC-delta, and nPKC by two- to sixfold. Membrane-associated PKC progressively increased, and cytosolic PKC decreased, for 1 h after the addition of TCA (50 microM); after 24 h whole cell cPKC-alpha, nPKC-delta, and nPKC were downregulated by 35-55% compared with untreated controls. In a reconstituted assay system, TCA or taurodeoxycholate (10-100 microM) increased calcium-dependent and -independent PKC activity by three- and fourfold, respectively. Taurine-conjugated bile acids stimulated PKC activity in proportion to their hydrophobicity index (r = 0.99). Finally, cholesterol 7 alpha-hydroxylase mRNA was repressed > 75% by phorbol 12-myristate 13-acetate (100 nM for 3 h), a nonselective activator of PKC isoforms. In contrast, selective cPKC-alpha activation with thymeleatoxin (100 nM for 3 h) had no significant effect on cholesterol 7 alpha-hydroxylase mRNA levels. We conclude that bile acids activate hepatocellular PKC, resulting in sequential redistribution and down-regulation of calcium-dependent and -independent isoforms. The calcium-independent PKC isoforms may mediate the repression of cholesterol 7 alpha-hydroxylase mRNA by TCA.

Topics: Animals; Cells, Cultured; Cholesterol 7-alpha-Hydroxylase; Enzyme Activation; Isoenzymes; Liver; Male; Protein Kinase C; Rats; Rats, Sprague-Dawley; RNA, Messenger; Taurochenodeoxycholic Acid; Taurocholic Acid

Functional dyspepsia (FD) includes a heterogeneous group of patients suffering from a variety of different conditions. The Dyspepsia Project has been implemented in 14 GI Units since 1984, in order to epidemiologically test the discriminating power of the Working Teams definitions and of standardized questionnaires. Five per cent of admitted subjects were subclassified as sphincter of Oddi dysfunction or biliary dyspepsia (BD), defined as biliary pain associated or not to bilirubin or alkaline phosphatase elevation, in the abscence of ultrasonographic evidence of gallstone disease or bile duct dilatation. The more useful symptoms in favour of the diagnosis of biliary dyspepsia were found to be pain in the right hypochondrium, radiating to the shoulder, or to the back, initiated by food, and eventually associated with constipation, or epigastric postprandial discomfort. Interestingly, symptoms suggesting biliary dyspepsia are partially shared by dysmotility-like dyspepsia. The placebo response in functional dyspepsia is variable, between 6 and 80% of patients, reflecting variations in the kind and severity of the diseases in different studies. That represents a considerable difficulty in evaluating drug efficacy, even in the case of biliary dyspepsia. A therapeutic double-blind trial in functional dyspepsia using tauro-ursodeoxycholic acid is discussed.

Topics: Adult; Biliary Tract Diseases; Dyspepsia; Female; Humans; Male; Middle Aged; Randomized Controlled Trials as Topic; Taurochenodeoxycholic Acid

Precipitation of cholesterol crystals is an essential step in gallstone formation. In the present study we found much faster and more extensive precipitation of various cholesterol crystal shapes in whole model biles containing the hydrophobic bile salt taurodeoxycholate than in biles containing the relatively hydrophilic taurocholate. Addition of taurodeoxycholate to isolated cholesterol-phospholipid vesicles also induced more crystallization than taurocholate. Crystallization behaviour in whole model biles and in vesicles after addition of corresponding bile salts was very similar. The very hydrophilic bile salts tauroursodeoxycholate and taurohyodeoxycholate never induced crystallization from vesicles, and crystallization in corresponding whole model biles did not occur. These bile salts also reduced crystallization dose dependently after addition of taurodeoxycholate to vesicles. Ultracentrifugation experiments suggested a higher vesicular cholesterol-phospholipid bile salts. These findings indicate that bile salt hydrophobicity influences shape of cholesterol crystals and extent of crystallization, possibly by modulating the vesicular cholesterol-phospholipid ratio.

Topics: Bile Acids and Salts; Cholelithiasis; Cholesterol; Crystallization; Humans; In Vitro Techniques; Models, Biological; Taurochenodeoxycholic Acid; Taurocholic Acid; Taurodeoxycholic Acid

The effects of ursodeoxycholate and its conjugates on biliary glutathione excretion were studied in rats. Ursodeoxycholate had no effect on glutathione excretion, but tauroursodeoxycholate (10 mumol/100 g body wt) transitionally increased biliary glutathione excretion. Ursodeoxycholate-3-O-glucuronide (2 and 10 mumol/100 g body wt) markedly inhibited biliary glutathione excretion, but ursodeoxycholate-3-sulfate (2 mumol/100 g body wt) and ursodeoxycholate-3,7-disulfate (10 mumol/100 g body wt) did not. These findings indicate the existence of several biliary excretion pathways for bile acid glucuronides and sulfates and that one of them for the glucuronides is shared by biliary glutathione excretion.

Topics: Animals; Bile; Glutathione; Liver; Male; Rats; Rats, Sprague-Dawley; Taurochenodeoxycholic Acid; Ursodeoxycholic Acid

Topics: Animals; beta-Alanine; Bile; Bile Acids and Salts; Bilirubin; Glycine; Hyperbilirubinemia; Jaundice; Liver; Male; Rats; Rats, Mutant Strains; Rats, Sprague-Dawley; Taurine; Taurochenodeoxycholic Acid; Ursodeoxycholic Acid

Taurohyodeoxycholic acid and tauroursodeoxycholic acid were infused intraduodenally at a rate of 0.8 g/h for three hours in 3 cholecystectomized T-tube patients. Biliary lipid secretion and bile acid composition were evaluated before and after replacement of the endogenous bile acid pool with the two bile acids. As compared to basal values (2.78 +/- 1.67 mM/l), taurohyodeoxycholic acid induced a greater increase in the biliary concentration of phospholipids (4.12 +/- 1.23 mM/l) as compared to tauroursodeoxycholic acid (3.14 +/- 0.98 mM/l). Biliary cholesterol concentration after taurohyodeoxycholic acid (1.89 +/- 0.63 mM/l) was unchanged as compared to the pretreatment period (1.98 +/- 0.58 mM/l), while it decreased significantly after tauroursodeoxycholic acid (0.85 +/- 0.08 mM/I). Biliary cholesterol secreted per unit of bile acid was greater during taurohyodeoxycholic acid than during tauroursodeoxycholic acid, while the opposite was observed for the secretion of phospholipids.

Topics: Bile; Bile Acids and Salts; Cholagogues and Choleretics; Cholesterol; Humans; Lipid Metabolism; Phospholipids; Taurochenodeoxycholic Acid; Taurodeoxycholic Acid

In most cases epithelial cells reveal a polarized distribution of integrin receptors in basolateral domains of the plasma membrane. To evaluate the functional state of integrin receptors in these restricted sites we were interested in the physical association of integrins with the cytoskeleton. Basically, we extracted cells with Triton X-100 to obtain detergent insoluble cytoskeleton fractions and used monoclonal antibodies for the detection of integrins linked to the cytoskeleton. We found that no permanent physical integrin-cytoskeleton associations exist in a confluent culture of the hepatocyte cell line mHepR1. However, incubation with anti-integrin antibodies and cross linking with a secondary antibody induced a physical linkage of beta1 as well as of different alpha subunits to the cytoskeleton. The association of integrins with the cytoskeleton was also inducible in suspended cells, which was detected in flow cytometric analyses and indicates that the formation of a physical integrin-cytoskeleton connection is independent of the localization of integrins, cell shape, and adhesion on a substrate. Using the Ca2+ chelators BAPTA-AM and EGTA, we found that intracellular calcium is a necessary prerequisite to induce a connection of integrins to the cytoskeleton. ATP or tauroursodeoxycholic acid, which provoke an intracellular calcium elevation, partly induced the formation of an integrin-cytoskeleton linkage. These results indicate the obvious role of intracellular calcium in integrin-dependent outside-in as well as inside-out signaling.

Topics: Adenosine Triphosphate; Animals; Calcium; Cell Fractionation; Cell Line; Cell Membrane; Chelating Agents; Cross-Linking Reagents; Cytoskeleton; Egtazic Acid; Epithelium; Flow Cytometry; Integrins; Liver; Mice; Microscopy, Electron; Octoxynol; Protein Binding; Taurochenodeoxycholic Acid

Biliary lipid secretion is a complex process involving a multitude of metabolic pathways. It has always been assumed that bile salt secretion (BSec) fully controls this process. Recently we have demonstrated, that mdr2 P-glycoprotein (P-gp) is an important controlling step as well. In this study we have analysed the control structure of this pathway with Metabolic Control Analysis.. FVB mice homozygous (+/+) or heterozygous (+/-) for mdr2 P-glycoprotein were infused via the tail vein with tauroursodeoxycholate in stepwise increasing concentrations. Bile was collected and biliary lipids were determined by standard techniques.. To simplify the pathway we have lumped all reactions involved in BSsec into bile in one step. Since this step is not controlled by the canalicular BS concentration, the FCC of BS secretion on phospholipid secretion (PLsec) could be calculated from a plot between BS and PL secretion. The FCC of BSsec varied from 80% at low flux to a value of 90% at maximal BS output. The FCC of mdr2 P-gp was determined by varying the gene dose of mdr2 P-gp. Since PLsec showed linear kinetics towards canalicular BS the FCC could be calculated via the Deviation index. The values for the FCC of mdr2 P-gp in (+/+) mice vary from 80% at low flux to 125% at maximal BS output.. Both BS secretion and mdr2 P-gp strongly control biliary phospholipid secretion. The sum of the FCCs of both steps is always much higher than 100% implicating the presence of step(s) which exert negative control. We hypothesize that steps controlling biliary water transport account for the negative control.

Topics: Animals; ATP Binding Cassette Transporter, Subfamily B; ATP Binding Cassette Transporter, Subfamily B, Member 1; ATP-Binding Cassette Transporters; Bile Acids and Salts; Biliary Tract; Computational Biology; Lipid Metabolism; Liver; Mice; Mice, Inbred Strains; Models, Biological; Taurochenodeoxycholic Acid

Protein is secreted into bile via several independent pathways. The aim of this study was to investigate whether these pathways are influenced by secretion of biliary lipid.. Protein secretion and biliary lipid output were studied in wild-type mice (+/+), heterozygotes (+/-), and homozygotes (-/-) for mdr2 gene disruption. Biliary lipid and protein output were varied by infusion with taurocholate (TC) and tauroursodeoxycholate (TUDC).. Exocytosis and transcytosis were unaltered in (-/-) mice. Infusion with TC strongly induced secretion of alkaline phosphatase in (-/-) mice but had little effect in (+/-) and (+/+) mice. Infusion with TUDC had little effect on alkaline phosphatase output. In contrast, both TUDC and TC strongly stimulated secretion of aminopeptidase N and lysosomal enzymes in (+/+) mice but had no effect in (-/-) animals. Aminopeptidase N secretion correlated with phospholipid output, but only at high flux. At low flux, aminopeptidase N was secreted independently from both phospholipid and bile salts.. The canalicular membrane enzymes alkaline phosphatase and aminopeptidase N are secreted via separate pathways. Part of alkaline phosphatase output is controlled by bile salt hydrophobicity, whereas at high lipid flux, aminopeptidase N secretion seems to be coupled to phospholipid output. Lysosomal enzymes follow the latter pathway.

Topics: Alkaline Phosphatase; Animals; ATP Binding Cassette Transporter, Subfamily B, Member 1; Bile; CD13 Antigens; Cholagogues and Choleretics; Enzyme-Linked Immunosorbent Assay; Genes; Lipid Metabolism; Mice; Mice, Transgenic; Mutation; Phospholipids; Proteins; Taurochenodeoxycholic Acid; Taurocholic Acid

Hepatic bile acid concentrations are elevated in chronic cholestasis because of reduced canalicular excretion and active ileal absorption of the fraction eliminated in the gut. Ursodeoxycholic acid (UDCA) reduces the intestinal absorption of endogenous bile acids, thereby diminishing the concentrations to which liver cells are exposed. In the isolated perfused liver (in which vectorial bile acid transport is maintained), UDCA reduces the cytotoxic and cholestatic effects of endogenous bile acids. As a result, it has been suggested that UDCA or one of its conjugates could have a direct protective effect on hepatocyte structure and function. We therefore studied the effects of chenodeoxycholic acid (CDCA) and tauroursodeoxycholic acid (TUDCA) alone and in combination on the viability and certain functions of human hepatocytes in primary culture. TUDCA did not affect intracellular concentrations of CDCA when added concomitantly. In other experiments, CDCA (100 to 500 mumol/L) induced concentration-dependent increases in lactate dehydrogenase (LDH) leakage and decreases in cellular protein synthesis and albumin secretion. Neither TUDCA nor UDCA had similar effects at the same concentrations, nor did they have a protective effect when added concomitantly with CDCA at equimolar or twice-equimolar concentrations. These results suggest that UDCA has no direct cytoprotective effect when the bile acid concentrations to which human hepatocytes are exposed are unchanged. They also suggest that the hepatoprotective effect of UDCA in cholestatic human liver diseases and in the isolated perfused liver loaded with hydrophobic bile acids occurs through its effect on intestinal and hepatocyte transport systems.

Topics: Bile Acids and Salts; Biotransformation; Cell Survival; Cells, Cultured; Chenodeoxycholic Acid; Humans; Intracellular Membranes; Isomerism; L-Lactate Dehydrogenase; Liver; Serum Albumin; Taurochenodeoxycholic Acid; Ursodeoxycholic Acid

Taurodeoxycholic acid (TUDCA) and ursodeoxycholic acid (UDCA) exert a protective effect in chronic cholestasis. This study reports the effect of TUDCA and UDCA on an in vitro model for ethanol-induced liver damage.. Hep G2 cells were incubated for 24 hours with 80 mmol/L ethanol in the presence or absence of 50 mumol/L TUDCA or UDCA. Cells were also pretreated with 80 mmol/L EtOH and then exposed to 50 mumol/L bile acids. Cytotoxicity was assessed by the metabolism of formazan (3-(4,5-dimethyl-thiazol-2-yl)-2, 5-diphenyl tetrazolium bromide and sodium 3,3'-(phenylamino) carbonyl-3,4-tetrazolium-bis (4-methoxy-6-nitro) benzene sulfonic acid hydrase and by the release into the culture medium of different enzymes (aspartate aminotransferase, glutamate dehydrogenase, gamma-glutamyl transferase, and lactate dehydrogenase).. The incubation of Hep G2 with EtOH significantly (P < 0.001) increased cytotoxicity. Both TUDCA or UDCA reduced cytoxicity to a similar extent (P < 0.001). Cells pretreated with EtOH and then added with TUDCA or UDCA responded differently because TUDCA was significantly more effective (P < 0.05) than an equimolar dose of UDCA in reversing the damage. Electron microscopic examination revealed that TUDCA and UDCA were both able to prevent mitochondrial damage and to reduce steatosis induced by EtOH.. Low doses of TUDCA and UDCA protect Hep G2 cells from EtOH-induced cytotoxicity. However, TUDCA seems to be more effective than UDCA in reversing the damage.

Topics: Cell Survival; Endoplasmic Reticulum; Humans; Liver Diseases, Alcoholic; Mitochondria; Models, Biological; Taurochenodeoxycholic Acid; Tumor Cells, Cultured; Ursodeoxycholic Acid

To explain the greater hepatoprotective effect of tauroursodeoxycholic acid vs. ursodeoxycholic acid, the absorption, hepatic enrichment, and biotransformation of these bile acids (250 mg/day) were compared in rats.. Bile acids were determined in intestinal contents, feces, urine, plasma, and liver by gas chromatography-mass spectrometry.. The concentration of ursodeoxycholate in the liver of animals administered tauroursodeoxycholic acid (175 +/- 29 nmol/g) was greater (P < 0.05) than in animals administered ursodeoxycholic acid (79 +/- 19 nmol/g). Hepatic lithocholate was substantially higher after ursodeoxycholic acid administration (21 +/- 10 nmol/g) than after tauroursodeoxycholic acid administration (12 +/- 1 nmol/g). A concomitant reduction in the proportion of hydrophobic bile acids occurred that was greatest during tauroursodeoxycholic acid administration. In the intestinal tract, the mass of ursodeoxycholate and its specific metabolites was greater in rats administered tauroursodeoxycholic acid (27.2 mg) than those administered ursodeoxycholic acid (13.2 mg). In feces, the proportion of lithocholate was 21.9% +/- 4.9% and 5.4% +/- 4.0% after ursodeoxycholic acid and tauroursodeoxycholic acid administration, respectively.. Compared with ursodeoxycholic acid, tauroursodeoxycholic acid induces a greater decrease in the percent composition of more hydrophobic bile acids within the pool, limits lithocholate formation, and increases hepatic ursodeoxycholate concentration. These differences are explained by increased hepatic extraction and reduced intestinal biotransformation and not by enhanced absorption of the amidated species.

Topics: Absorption; Animals; Biotransformation; Feces; Gas Chromatography-Mass Spectrometry; Intestines; Lithocholic Acid; Liver; Male; Plasma; Rats; Rats, Sprague-Dawley; Taurochenodeoxycholic Acid; Urine; Ursodeoxycholic Acid

The effects of ursodeoxycholate and its taurine conjugate on biliary Tm of bilirubin were evaluated in rats. Ursodeoxycholate was administered at four different doses (4, 8, 12 or 16 mumol per 100 g body wt i.v., followed by an i.v. infusion of 0.3, 0.6, 0.9 or 1.2 mumol/min per 100 g body wt, respectively), whereas tauroursodeoxycholate was administered only at the maximal dose. A dose-dependent diminution of bilirubin Tm was observed during ursodeoxycholate administration, which ranged from no effect at the lowest dose to a virtual excretory blockage at the highest dose. This was associated with an increase in bilirubin concentrations in both plasma and liver as well as in the fractional amount of conjugated pigment in both sites, suggesting an impairment of bilirubin transfer at the canalicular level. Incomplete taurine conjugation of ursodeoxycholate well correlated with these effects. Unlike ursodeoxycholate, tauroursodeoxycholate had no inhibitory effect on bilirubin Tm, although a slight inhibition of bilirubin uptake and bilirubin conjugation became apparent. Taken together, these results suggest that ursodeoxycholate interferes with the hepatobiliary transport of bilirubin by impairing its transfer at the canalicular level and that incomplete taurine conjugation appears to be a key factor determining this effect.

Topics: Animals; Bile; Bile Acids and Salts; Bilirubin; Biological Transport; Dose-Response Relationship, Drug; Liver; Male; Rats; Rats, Wistar; Taurochenodeoxycholic Acid; Ursodeoxycholic Acid

The purpose of this study was to investigate the physicochemical/biological properties and the effects of acute administration of N-ethyl-tauroursodeoxycholic acid in bile-fistula rats. In vitro determination of high-performance liquid chromatography mobility, octanol/ water partitioning, cholesterol solubilizing capacity, and sensitivity to enzyme deconjugation by bacteria and cholylglycine-hydroxylase were performed. In vivo determination of the following was also performed: (1) maximum secretory rate (SRmax) and choleretic/secretory properties during intravenous (IV) administration; (2) site/ extent of absorption, effects on bile flow, lipid secretion, and biotransformations after intraduodenal infusion. N-ethyl-tauroursodeoxycholate has a lipophilicity slightly higher than tauroursodeoxycholate, close to taurocholate, and similar cholesterol solubilizing capacity. Deconjugation of N-ethyl-tauroursodeoxycholate was 3.4 +/- 2.1% after 72 hours, that of tauroursodeoxycholate was 100% after 24 hours. During IV infusion of 300 nmol/min/ 100g, biliary secretion of N-ethyl-tauroursodeoxycholic and tauroursodeoxycholic acids averaged 185 +/- 76 (standard deviation) nmol/min/100 g and 221 +/- 77 nmol/min/ 100 g (not significant). Increasing infusion rates caused progressive enhancement of bile flow and bile salt secretion until the SRmax was reached (1,305 +/- 240 nmol/min/ 100 g for N-ethyl-tauroursodeoxycholic acid and 3,240 nmol/min/100 g for tauroursodeoxycholate). The two bile salts were similarly choleretic. IV feeding of N-ethyl-tauroursodeoxycholic promoted a greater lipid secretion than tauroursodeoxycholate. After intraduodenal feeding of 800 mumol, 38.8 +/- 14.0% and 43.4 +/- 12.4% of the two bile salts were recovered in bile. No unconjugated bile salts nor unusual metabolites were detected.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Animals; Bile; Bile Acids and Salts; Chemical Phenomena; Chemistry, Physical; Duodenum; Infusions, Intravenous; Injections; Male; Rats; Rats, Wistar; Taurochenodeoxycholic Acid

We investigated whether bile salts (BS) with different hydrophobic-hydrophilic properties interact with ethanol on bile secretion, enzyme (aspartate transaminase [AST], lactate dehydrogenase [LDH]) release in the perfusate, liver ultrastructure, and vesicular exocytosis in the isolated perfused rat liver. Ethanol (0.1 or 1%) promoted a rapid decrease of bile flow and BS secretion in livers perfused with taurocholate (TCA), the physiologic BS in the rat (-28% decrease of baseline values with 0.1% and -34% with 1% ethanol). The inhibitory effect of ethanol on bile flow and BS secretion was significantly (P < .02) attenuated by perfusing liver with the hydrophilic BS, tauroursodeoxycholate (TUDCA), and it was exacerbated (P < .02) by perfusion with the hydrophobic BS, taurodeoxycholate (TDCA). The release of AST and LDH in the perfusate was unaffected by 0.1% ethanol, but increased threefold to fivefold by 1% ethanol in TCA-perfused livers. This cytolitic effect of ethanol was not observed in TUDCA-perfused livers, but it was enhanced (P < .03) by perfusion with TDCA. No ultrastructural abnormalities were found in either TCA- or TUDCA-perfused livers, with or without 1% ethanol. Only minimal changes were found in livers perfused with TDCA alone, but, in the presence of TDCA, 1% ethanol induces marked mitochondrial damage. The biliary excretion of the fluid phase marker horseradish peroxidase was inhibited by ethanol, an effect reversed by TUDCA (P < .02) and exacerbated by TDCA (P < .04). In conclusion, this study demonstrates that hydrophilic BS such as TUDCA counteract the inhibitory effect of ethanol on bile secretion and vesicular exocytosis as well as the ethanol-induced cytolitic effect in the isolated perfused rat liver. In the presence of hydrophobic BS such as TDCA, the exposure to ethanol promotes a marked inhibition of bile secretion and vesicular exocytosis as well as prominent mitochondrial damage.

Topics: Animals; Aspartate Aminotransferases; Bile; Bile Acids and Salts; Ethanol; L-Lactate Dehydrogenase; Liver; Male; Perfusion; Rats; Rats, Wistar; Taurochenodeoxycholic Acid; Taurocholic Acid; Taurodeoxycholic Acid

It has been suggested that vesicular transport of bile acids in hepatocytes occurs, especially at high-dose loads.. The effect was studied of colchicine, a vesicular transport inhibitor, on lithocholate-3-O-glucuronide-induced cholestasis in rats. Cholestasis was induced by an intravenous infusion of lithocholate-3-O-glucoronide at the rate of 0.1 mumol.min-1.100 g-1 for 40 min.. Colchicine treatment almost completely inhibited cholestasis and increased biliary excretion of lithocholate-3-O-glucoronide, whereas lumicolchicine had no effect. Treatment with vinblastine, another vesicular transport inhibitor, also reduced the cholestasis. Colchicine did not affect biliary excretion of taurocholate infused at the rate of 0.3 mumol.min-1.100 g-1 for 40 min, but markedly inhibited its biliary excretion when infused at the rate of 1.5 mumol.min-1.100 g-1 for 40 min. Colchicine had no effect on biliary excretion of tauroursodeoxycholate (1.5 mumol.min-1.100 g-1 for 40 min), lithocholate-3-sulfate (0.3 mumol.min-1.100 g-1 for 40 min), or a trace amount of lithocholate-3-O-glucuronide.. These findings indicate that lithocholate-3-O-glucoronide-induced cholestasis is caused by its increased access to the vesicular transport pathway, possibly beyond the capacity of the transport by the cytosolic binders, and that the transport of lithocholate-3-O-glucoronide via the vesicular pathway induces cholestasis. Furthermore, the contribution of the vesicular pathway to hepatic transport may be different among bile acids, and lithocholate-3-O-glucuronide seems to have higher accessibility to this transport system.

Topics: Animals; Bile; Cholestasis; Colchicine; Glucuronates; Lithocholic Acid; Male; Rats; Rats, Sprague-Dawley; Taurochenodeoxycholic Acid; Taurocholic Acid; Vinblastine

The appearance of gallstone opacification during oral bile acid administration indicates that stones are no longer susceptible to dissolution and represents, therefore, a definitive treatment failure. Ursodeoxycholic acid (UDCA) has been imputed to facilitate gallstone opacification; however, data regarding the comparative occurrence of gallstone opacification during UDCA and chenodeoxycholic acid (CDCA) administration are not yet available. Our objectives were to evaluate the frequency of acquired opacification in gallstone patients taking UDCA and in gallstone patients taking CDCA, to verify whether or not gallstone opacification is a peculiar side effect of UDCA treatment and, further, to evaluate gallstone opacification in gallstone patients receiving tauro-UDCA (TUDCA) to verify whether the administration of the more soluble tauroconjugate might prevent the deposition of calcium salts on the stone surface.. 106 gallstone patients on UDCA, 125 gallstone patients on CDCA, and 31 gallstone patients on TUDCA were evaluated. Before treatment, all patients had radiolucent gallstones as assessed by oral cholecystography; further cholecystographic evaluations were performed every 6 months during treatment.. The frequency of gallstone opacification was 13.2% (14/106) in UDCA patients, 8.8% (11/125) in the CDCA patients, and 12.9% (4/31) in the TUDCA patients. The differences were not statistically significant (p = NS). Sex, stone size, dose of bile acid, and duration of treatment were not significantly related to an increased frequency of gallstone calcification in any of the treatment groups. The frequency of gallstone opacification appeared to be higher in older patients.. 1) UDCA rich bile is not a major predisposing factor for acquired gallstone opacification; 2) the administration of TUDCA does not prevent gallstone opacification; 3) opacification could be related to the natural history of gallstone disease.

Topics: Adolescent; Adult; Aged; Chenodeoxycholic Acid; Cholecystography; Cholelithiasis; Female; Humans; Male; Middle Aged; Taurochenodeoxycholic Acid; Ursodeoxycholic Acid

Despite numerous studies on the effects of bile salts therapy in chronic liver disease, there are no reports on the influence such therapy has on hepatocyte proliferation. The aim of this preliminary study was to evaluate the effect of TUDCA on hepatocyte proliferation in 5 patients with HCV-correlated chronic liver disease. All patients were treated with TUDCA (10-13 mg/day) for three months and the determination of PCNA (Proliferating Cell Nuclear Antigen) expression was used to assess the proliferative activity of hepatocytes at the beginning and at the end of treatment. TUDCA reduced both ALT and Knodell's score in the 5 patients in whom a significant increase of PCNA-LI (p < 0.05) was observed after treatment. TUDCA administration seems to stimulate hepatocyte proliferation in man.

Topics: Cell Division; Chronic Disease; Female; Humans; Liver Diseases; Male; Proliferating Cell Nuclear Antigen; Taurochenodeoxycholic Acid

Taurochenodeoxycholate (TCDC) (or taurocholate, TC) excessively i.v. infused in rats causes an acute cholestasis accompanied by an excessive excretion of various proteins (lactate dehydrogenase, LDH, albumin, etc.) into the bile. This cholestasis was initially found to be effectively prevented by a simultaneous infusion of tauroursodeoxycholate (TUDC). Later this property was found to be shared by glycoursodeoxycholate (GUDC) and tauro (and glyco) alpha and beta-muricholate (MC) all known to be relatively hydrophilic. The extent of the preventative effect appears to be comparable for taurine and glycine conjugates of all three bile salts (UDC, alpha-MC and beta-MC). An albumin leakage into the bile enhanced by TCDC infusion appears to be mainly from albumin in the serum, since i.v. injected 125I-human serum albumin excretion into the bile paralled the rat albumin excretion. Despite very drastic biochemical abnormalities induced by TCDC infusion, morphological correlates in the liver are scarce both from light and electron microscopic examinations, the only correlate with biochemical parameters being a sporadic necrosis of hepatocytes, especially in the periportal areas. Although there is not sufficient morphological evidence, it appears that TCDC infusion causes a direct communication between serum and bile leading to a rapid leakage of large molecules such as albumin and even gamma-globulin. Conjugates of hydrophilic bile salts such as UDC, alpha-MC and beta-MC efficiently prevent such bile abnormalities but their hydrophilicity is not the sole determinant of this property since a more hydrophilic bile salt such as taurodehydrocholate does not possess this property. The underlying mechanism(s) for this protective property remains uncertain.

Topics: Albumins; Animals; Bile; Bile Acids and Salts; Cholestasis; Cholic Acids; L-Lactate Dehydrogenase; Liver; Male; Necrosis; Rats; Rats, Wistar; Taurochenodeoxycholic Acid

We present evidence that ursodeoxycholate prevents toxicity of more hydrophobic bile salts by inhibiting micellar solubilization of membrane lipids. Using both centrifugal ultrafiltration and gel filtration methods we studied leakage of inulin from vesicles composed of egg phosphatidylcholine and cholesterol. We observed that the addition of tauroursodeoxycholate to taurodeoxycholate reduced leakage of inulin from large unilamelar vesicles compared to that seen with taurodeoxycholate alone. This protective effect was observed only at high membrane cholesterol:phospholipid ratios (> or = 0.5). By gel filtration we found that fractional leakage of inulin from vesicles was identical to fractional phospholipid solubilization, indicating that release of inulin from vesicles results from membrane dissolution rather than from increased permeability of otherwise intact membranes. Addition of tauroursodeoxycholate to taurodeoxycholate was found to suppress the dissolution of phospholipid from cholesterol-rich vesicles. Bile salts were found to absorb to vesicles with an affinity proportional to their relative hydrophobicity, as estimated by reverse phase HPLC. Adsorption affinity decreased progressively with increasing membrane cholesterol content. Different bile salts displaced each other from membranes in proportion to their respective binding, affinities. Tauroursodeoxycholate, which absorbed to membranes with low affinity, displaced taurodeoxycholate from vesicles only weakly. Based on these findings we postulate that bile salts may damage the liver through solubilization of canalicular membrane lipids. Ursodeoxycholate may protect the liver by inhibiting dissolution of the cholesterol-rich canalicular membrane by more hydrophobic endogenous bile salts. Biliary secretion of vesicles rich in phosphatidylcholine may buffer the intermicellar concentration of bile acids at levels below those required to disrupt the cholesterol-rich canalicular membrane; thus biliary vesicle secretion may have evolved as a mechanism to protect the biliary epithelium from injury by luminal bile salts.

Topics: Bile Acids and Salts; Cholesterol; Chromatography, Gel; Chromatography, High Pressure Liquid; Inulin; Membranes, Artificial; Permeability; Phosphatidylcholines; Taurochenodeoxycholic Acid; Taurodeoxycholic Acid; Ultrafiltration; Ursodeoxycholic Acid

Tauroursodeoxycholic acid is known to have a hepatoprotective action in cholestatic disorders. We evaluated whether oral pretreatment with tauroursodeoxycholic acid could protect the liver from ischemia-reperfusion injury, with particular regard to its effect on bile flow and biliary calcium excretion.. A 1-hour in vivo ischemia-reperfusion model of 70% of the lobes of rat liver was used. Animals were divided into six groups (each group; n = 8); a non-ischemia sham group (CS), a control group without bile acids (CON), and 4 bile acid groups; 10 mg/kg and 50 mg/kg (U10, U50), taurocholic acid 10 mg/kg (CA10) and tauroursodeoxycholic acid 10 mg/kg (CD10). Bile acids were given orally for 7 days before operation.. Three hours after reperfusion, oral bile acid pretreatment failed to reduce the hepatic ischemia-reperfusion injury biochemically, but histological improvement was observed in the tauroursodeoxycholic acid groups. After reperfusion, tauroursodeoxycholic acid significantly increased bile flow from the ischemic liver, and also significantly increased serum calcium concentration. Although tauroursodeoxycholic acid did not change biliary calcium concentration, it significantly enhanced total biliary calcium output during reperfusion.. Thus, tauroursodeoxycholic acid inhibited tissue calcium accumulation and enhanced sinusoidal and biliary calcium output during hepatic ischemia-reperfusion. However, it is still unclear if calcium mobilization is part of the protective mechanisms of tauroursodeoxycholic acid in ischemia-reperfusion injury of the liver.

Topics: Analysis of Variance; Animals; Bile Acids and Salts; Calcium; Cholestasis; Evaluation Studies as Topic; Isomerism; Liver; Male; Rats; Rats, Sprague-Dawley; Reperfusion Injury; Stimulation, Chemical; Taurochenodeoxycholic Acid

Unconjugated bile salts currently available for gallstone dissolution are poorly effective. We evaluated in vitro the litholytic potency of taurine-amidated bile salts against human cholesterol gallstones.. Seventy radiolucent gallstones with similar size and composition (cholesterol content, 70.1 +/- 0.9%) from a single patient were incubated in model biles composed of 100 mM of either taurochenodeoxycholate (TCDC), taurocholate (TC), taurohyodeoxycholate (THDC) or tauroursodeoxycholate (TUDC) and of 45 mM egg yolk lecithin in saline buffered with tris/HCl (at pHs 7 and 8) or phosphate (at pHs 4 and 6). Biles (total lipids, 10 g/dl; cholesterol saturation, 99%) were incubated at 37 degrees C for 40 days. Gallstones were periodically weighed and returned to the dissolution vials, and the biliary cholesterol concentration was monitored.. Model biles remained optically clear during the initial 48 h of incubation. Then, biles containing THDC and TUDC, but not those with TC and TCDC, became progressively turbid until, after several days, a white precipitate surrounded the residual stone. Abundant liquid crytalline droplets were observed at polarizing microscopy in biles containing TUDC and THDC. Gallstone dissolution was closely related to cholesterol solubilization and decreased in the order TCDC > THDC > or = TC > TUDC, being highest at pH 8. At the physiologic pH of 7 THDC was more litholythic than TC.. In vitro, the litholytic potency of bile salts on cholesterol gallstones primarily depends on their hydrophobicity. THDC is a new potential gallstone-dissolving agent, deserving in vivo studies.

Topics: Cholagogues and Choleretics; Cholelithiasis; Cholesterol; Drug Combinations; Drug Evaluation, Preclinical; Humans; Hydrogen-Ion Concentration; Phosphatidylcholines; Taurochenodeoxycholic Acid; Taurodeoxycholic Acid

The existence of transporters for bile acids (BA) in liver and intestine has been well documented, but information is still needed as to their respective transport capacity. In the present investigation, we compared the hepatic and intestinal transport rates for BA, using perfused livers and intestines. The livers and intestines were separately perfused and dose-response curves (0.25-10 mM) for tauroursodeoxycholate, taurocholate and taurodeoxycholate were obtained. The intestinal and mesenteric concentration and bile acid pattern were also evaluated in six non-fasting rabbits. Taurocholic, tauroursodeoxycholic and taurodeoxycholic acid ileal absorption showed saturation kinetics in the intestine as in the liver; the maximal uptake velocity for each bile acid in the liver was tenfold higher than the respective maximal transport velocity in the intestine; the Km values obtained in the liver were of the same order of magnitude, i.e. in the millimolar range. Taurocholic, tauroursodeoxycholic and taurodeoxycholic acid transport differences in the liver paralleled those in the intestine. Although the intestine was not homogeneously filled, the bile acid concentration in the ileal content fell into the range of the Km for the three studied bile acids, while the portal blood total bile acid concentration was inferior to the observed Kms of liver uptake. Therefore, both the hepatic and intestinal systems do not operate at their maximal transport rates at the prevailing concentrations in portal blood and luminal content, and the hepatic transport occurs at its highest efficiency (below the Km values) in physiological conditions.

Topics: Animals; Bile Acids and Salts; Intestinal Absorption; Liver; Male; Rabbits; Taurochenodeoxycholic Acid; Taurocholic Acid; Taurodeoxycholic Acid

The transcytotic vesicular pathway in isolated rat hepatocyte couplets was investigated using horseradish peroxidase. Ten to 20 min after horseradish peroxidase labeling, vesicles and tubules containing horseradish peroxidase were observed to be predominantly around the bile canaliculi. In hepatocytes incubated in a 4 degrees C medium for 10 min after horseradish peroxidase labeling, few horseradish peroxidase-containing structures were observed around the bile canaliculi, and the fine reticular immunofluorescence of microtubules was reduced. Cells treated with cytochalasin B (a microfilament inhibitor) showed a fair number of horseradish peroxidase-containing structures around the markedly dilated bile canaliculi and the distribution of microtubules was preserved. Cells labeled by horseradish peroxidase and then incubated for 10 min in a horseradish peroxidase-free medium containing 50 mumol/L of taurocholic acid, ursodeoxycholic acid or tauroursodeoxycholic acid had more tubular structures containing horseradish peroxidase around the bile canaliculi than control cells, whereas 50 mumol/L of taurochenodeoxycholic acid, taurodeoxycholic acid, dehydrocholic acid and taurodehydrocholic acid each failed to increase the number of tubular structures. These findings show that horseradish peroxidase was transported in hepatocyte couplets from the cell periphery to the bile canalicular front through the tubulovesicular pathway, depending on cytoplasmic microtubules. Cytoplasmic microfilaments appeared to play a minor role in this transport. Several specific bile acids such as taurocholic acid, ursodeoxycholic acid and tauroursodeoxycholic acid each promoted the tubular transformation.

Topics: Animals; Bile Acids and Salts; Bile Canaliculi; Biological Transport; Cells, Cultured; Cytochalasin B; Cytoplasmic Granules; Histocytochemistry; Horseradish Peroxidase; Liver; Male; Microscopy, Electron; Microtubules; Rats; Rats, Wistar; Taurochenodeoxycholic Acid; Taurocholic Acid; Temperature; Ursodeoxycholic Acid

Taurohyodeoxycholic acid is a natural 6 alpha-hydroxylated bile acid with an apparent hydrophilicity intermediate between those of tauroursodeoxycholic and taurocholic acids. We investigated in the rat the hepatobiliary metabolism, choleretic properties, and biliary maximum secretory rate (SRmax) of taurohyodeoxycholic in comparison with these two bile salts. Each compound was infused intravenously, at a rate increased in a stepwise manner from 100 to 300 nmol/min/100 g body wt, in bile salt-depleted bile fistula rats. The three bile salts appeared rapidly starting with the infusion and increased to represent more than 95% of the total bile salts. No apparent biliary metabolites were formed. All the bile salts caused a dose-dependent increase in bile flow and biliary lipid output. The absolute increase in bile flow was lower in rats infused with taurohyodeoxycholic acid, yet the volume of bile formed per nanomole of secreted bile salt was 13.8 nl for taurohyodeoxycholic, 6.4 nl for tauroursodeoxycholic acid, and 10.9 nl for taurocholic. The SRmax values were 1080, 3240, and 960 nmol/min/100 g, respectively. At all infusion rates, taurohyodeoxycholic acid caused a greater (P < 0.001) secretion of biliary lecithin compared to the other bile salts. There were no significant differences in the biliary secretion of cholesterol and proteins. Electron microscopy showed the recruitment of vesicles and lamellar bodies around and within bile canaliculi. In conclusion, taurohyodeoxycholic promotes a biliary lecithin secretion greater than expected from physicochemical predictions, representing a novel secretory property with potential pharmacological relevance.

Topics: Animals; Bile; Bile Acids and Salts; Cholagogues and Choleretics; Chromatography, High Pressure Liquid; Lipid Metabolism; Liver; Male; Rats; Rats, Wistar; Secretory Rate; Taurochenodeoxycholic Acid; Taurocholic Acid; Taurodeoxycholic Acid

We investigated the effects of intestinal bile acid flux, orientation of the 7-hydroxy group, and administration of lovastatin on the regulation of intestinal 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase activity in the rat ileum. HMG-CoA reductase activities in villous and crypt cells from the ileal mucosa were similar, and the study was performed on whole mucosa that contained both cell types. Taurocholate feeding decreased ileal reductase activity 48%, whereas tauroursocholate, the 7 beta-hydroxy epimer of taurocholate, had no effect. Feeding lovastatin (inhibitor of HMG-CoA reductase) stimulated total ileal HMG-CoA reductase activity threefold in washed microsomes, which were dissociated from the inhibitor. However, the proportion of active enzyme in the ileum of lovastatin-fed rats was 50% lower than in controls, whereas there was no change in the percentage of expressed enzyme with bile acid treatments. Interruption of the enterohepatic circulation (bile fistula) increased HMG-CoA reductase activity in the ileum 73%. Duodenal infusion of taurocholate to bile-fistula rats significantly decreased microsomal HMG-CoA reductase activity in the ileal mucosa. In contrast, infusion of the 7 beta-hydroxy epimer tauroursocholate failed to inhibit the derepressed HMG-CoA reductase activity in the ileum of bile-fistula rats. The inhibition of intestinal HMG-CoA reductase activity by taurocholate occurred without accumulation of mucosal cholesterol. Furthermore, the stimulation of total ileal HMG-CoA reductase activity by lovastatin treatment was observed without a decrease in mucosal cholesterol. In summary, the regulation of ileal HMG-CoA reductase activity by the intestinal luminal flux of bile acids is dependent on the orientation of the hydroxyl groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Acyl Coenzyme A; Animals; Bile Acids and Salts; Cholesterol; Cholesterol Esters; Diet; Ileum; Intestinal Mucosa; Jejunum; Lovastatin; Male; Microsomes; Rats; Rats, Sprague-Dawley; Taurochenodeoxycholic Acid; Taurocholic Acid

The effect of ursodeoxycholate and tauroursodeoxycholate on the toxicity of lipophilic bile acids (chenodeoxycholate and lithocholate) on the function of the electron transport chain was investigated in isolated rat liver mitochondria. At a concentration of 30 mumol/L, both chenodeoxycholate and lithocholate reduced state 3 oxidation rates and respiratory control ratios of L-glutamate, succinate and duroquinol. In contrast, ADP/O ratios of these substrates and oxidative metabolism of ascorbate were not significantly affected. Ursodeoxycholate did not impair mitochondrial oxidative metabolism up to concentrations of 100 mumol/L; at 300 mumol/L, however, it decreased state 3 oxidation rates and respiratory control ratios of L-glutamate, succinate and duroquinol. Tauroursodeoxycholate had no significant inhibitory effect on state 3 oxidation rates of L-glutamate and succinate at concentrations up to 300 mumol/L. When ursodeoxycholate (final concentration, 30 mumol/L or 100 mumol/L) was added to mitochondrial incubations containing chenodeoxycholate or lithocholate, the toxic effects of lipophilic bile acids on mitochondrial oxidative metabolism were partially reversed. However, 300 mumol/L ursodeoxycholate, in combination with chenodeoxycholate or lithocholate, exhibited greater toxicity compared with incubations containing only the individual bile acids. In contrast to ursodeoxycholate, tauroursodeoxycholate did not reduce the toxic effects of chenodeoxycholate or lithocholate on mitochondrial metabolism. Ursodeoxycholate (100 mumol/L) significantly decreased the incorporation of chenodeoxycholate into mitochondrial membranes, whereas the decrease in lithocholate incorporation was not statistically significant. These studies demonstrate that ursodeoxycholate, but not tauroursodeoxycholate, decreases the toxicity of lipophilic bile acids on the function of the electron but increases bile acid-induced mitochondrial toxicity at higher concentrations.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Analysis of Variance; Animals; Bile Acids and Salts; Chenodeoxycholic Acid; Dose-Response Relationship, Drug; Electron Transport; In Vitro Techniques; Lithocholic Acid; Male; Mitochondria, Liver; Oxidation-Reduction; Oxygen; Rats; Rats, Sprague-Dawley; Taurochenodeoxycholic Acid; Ursodeoxycholic Acid

Ursodeoxycholic acid and its endogenous metabolite tauroursodeoxycholic acid inhibited in vitro the microsomal bilirubin UDP-glucuronosyltransferase from rat liver. The magnitude of the inhibition correlated well with the loss of integrity of microsomal vesicles, suggesting that bile salts needed to reach the lumen to exert their inhibitory effects. The endogenous bile acids cholic acid, chenodeoxycholic acid and deoxycholic acid also exhibited inhibitory effects on bilirubin glucuronidation in digitonin-disrupted microsomes. Ursodeoxycholic acid inhibitory capacity was similar to that of chenodeoxycholic acid and deoxycholic acid but greater than that of cholic acid, the major endogenous bile salt. Kinetic studies, performed in detergent-activated preparations, showed that the inhibitions produced by ursodeoxycholic and tauroursodeoxycholic acids were competitive toward both bilirubin and UDP-glucuronic acid. The estimated Ki(app) for both substrates did not differ statistically between ursodeoxycholic and tauroursodeoxycholic acids. Both bile salts were weak inhibitors toward bilirubin but rather strong inhibitors toward UDP-glucuronic acid.

Topics: Animals; Bile Acids and Salts; Digitonin; Enzyme Activation; Glucuronates; Glucuronosyltransferase; Kinetics; Male; Membranes; Microsomes, Liver; Phosphoric Monoester Hydrolases; Rats; Rats, Wistar; Taurochenodeoxycholic Acid; Ursodeoxycholic Acid

Cyclosporin A is an essential immunosuppressive drug, but it is potentially toxic to the kidney and liver. Ursodeoxycholic acid, a hydrophilic bile acid, has been reported to improve cholestasis in liver disease in man. The purpose of this work was to examine whether tauroursodeoxycholate could reduce cyclosporin A-induced hepatic or renal injuries in the rat. After randomization into three groups (N = 8), rats received daily for 17 days: cyclosporin A intraperitoneally alone (30 mg/kg) or cyclosporin A intraperitoneally and tauroursodeoxycholate (60 mg/kg) by gavage; control received the cyclosporin A excipient. Under tauroursodeoxycholate, cholestatic parameters (bile flow, bile salt secretion, serum bile salts, serum bilirubin) improved significantly without affecting cyclosporin A blood levels, and excretion of the drug and its metabolites in bile increased by 47%. Serum creatinine levels were better preserved, although not significantly. These results show that tauroursodeoxycholate prevents cyclosporin A-induced cholestasis in long-term treatment in rats, possibly by facilitating the drug elimination in bile.

Topics: Animals; Cholestasis; Cyclosporine; Isomerism; Male; Random Allocation; Rats; Rats, Sprague-Dawley; Taurochenodeoxycholic Acid

Male Wistar rats were infused intravenously with taurochenodeoxycholate (0.4 mumol/min/100 gm) alone (group A) or with one of the three bile salts (tauroursodeoxycholate [group B], tauro beta-muricholate [group C] or tauro alpha-muricholate [group D]) at a rate of 0.2 mumol/min/100/gm for 1 hr. One-hour bile flow and bile salt excretion rates were significantly lower in group A than in the other three coinfused (B, C, D) groups. Biliary 1-hr outputs of lactate dehydrogenase and albumin in the bile, on the other hand, were significantly higher in group A than in the other groups. Plasma concentrations of lactate dehydrogenase at the time of killing (1 hr) were two to three times higher in group A than in the other groups. Although tauro alpha-muricholate does not possess a 7 beta-hydroxy group, the 6 beta-hydroxy group that tauro alpha-muricholate possesses thus appears to be as effective as a 7 beta-hydroxy group in reducing the liver damage caused by toxic bile salts such as taurochenodeoxycholate. The so-called hepatoprotective effects of tauroursodeoxycholate and tauro beta-muricholate found in previous studies may require explanation(s) other than the presence of a 7 beta-hydroxy group in their molecular structures.

Topics: Albumins; Animals; Bile; Cholestasis; Isomerism; L-Lactate Dehydrogenase; Liver; Male; Rats; Rats, Wistar; Taurochenodeoxycholic Acid; Taurocholic Acid

Our previous studies have shown that Tm values for tauroursodeoxycholate (TUDC) and tauro beta-muricholate (T beta-MC) are more than two-fold higher than that for taurocholate (TC) in the rat. The present study attempted to clarify whether tauro alpha-muricholate (T alpha-MC) also has such an unusually large Tm value in the rat. Under nembutal anesthesia, male Wistar derived rats (body weight 280-300 g, 13 wks in age) were continuously infused with T alpha-MC solution. The infusion rate was raised stepwise every 20 min, until the bile flow began to decline. Bile was collected every 10 min and bile salt excretion rate was determined. The average of the highest three excretion values was assumed to be the Tm in each animal. The Tm value of T alpha-MC was found to be 2.86 +/- 0.36 mumol/min/100 g (mean +/- SD, n = 4), which was even greater than Tm values for TUDC (2.59 +/- 0.39 mumol/min/100 g, n = 4) and T beta-MC (1.93 +/- 0.31 mumol/min/100 g, n = 4) as we reported previously. The relationship between the bile flow rate (microliter/min/100 g, Y axis) and bile salt excretion rate (mumol/min/100 g, X axis) was highly linear [Y = (6.00 +/- 0.29) x +(6.60 +/- 1.88), P < 0.001, r = 0.95, n = 54]. The slope value for T alpha-MC (6.00 +/- 0.29 microliters/mumol) was significantly higher than that for TUDC (4.76 +/- 0.71 microliters/mumol) and was comparable to that for T beta-MC as we previously found for these bile salts in this rat strain. The results suggest that T alpha-MC has a very efficient transport system in this species as was observed for the other two bile salts that have a 7 beta-hydroxy group (TUDC and T beta-MC). This efficient transport system thus appears to be shared not only by bile salts specifically having a 7 beta-hydroxy group, but also by other bile salts such as T alpha-MC that have a 6 beta-hydroxy group but not a 7 beta-hydroxy group.

Topics: Animals; Bile; Biliary Tract; Biological Transport; Male; Rats; Rats, Wistar; Taurochenodeoxycholic Acid; Taurocholic Acid

To clarify a possible pathogenic role for bile salts in the hyperdynamic circulation of cirrhosis, we studied the vasoactive effects of three different bile salts-tauroursodeoxycholic acid, taurochenodeoxycholic acid and taurodeoxycholic acid-in cirrhotic rats. Cirrhosis was induced with bile duct ligation; controls underwent sham surgery. In vivo, the bile salts were intravenously infused at one of three doses (1.2 x 10(-7), 1.2 x 10(-6) and 6.0 x 10(-5) mol x 100 gm-1 x min-1) for 5 min. Taurochenodeoxycholic acid and taurodeoxycholic acid infusions increased mesenteric arterial blood flow and conductance and induced systemic arterial hypotension, whereas tauroursodeoxycholic acid had no significant effect. At similar plasma levels of bile salts, the responses in cirrhotic rats were attenuated compared with those of controls. In vitro, isolated rings of superior mesenteric and carotid arteries and portal vein were precontracted with phenylephrine; then dilatory responses to cumulative doses of bile salts (10(-6) to 10(-3) mol/L) were measured. In all three vessels, taurodeoxycholic acid produced stronger dilatory effects than did taurochenodeoxycholic acid, whereas tauroursodeoxycholic acid showed no significant effect. Vessels from cirrhotic and control rats did not differ in degree of response. These results indicate that bile salts are directly vasoactive and can induce splanchnic vasodilation at the pathophysiological plasma levels seen in cirrhosis. Bile salts may be involved in the pathogenesis of splanchnic hyperemia and hyperdynamic circulation in cirrhosis.

Topics: Animals; Bile Acids and Salts; Hyperemia; Hypotension; In Vitro Techniques; Liver Cirrhosis, Biliary; Male; Mesenteric Arteries; Rats; Rats, Sprague-Dawley; Regional Blood Flow; Splanchnic Circulation; Taurochenodeoxycholic Acid; Taurodeoxycholic Acid; Vasodilation; Vasodilator Agents

The secondary messenger cyclic AMP plays an important role in regulating biliary excretory function by stimulating the transcytotic vesicle transport system, whereas papaverine exerts an inhibitory effect on this system. We therefore investigated their effects on bile acid-induced cytotoxicity and intrahepatocytic content of bile acid in primary cultured rat hepatocytes. Simultaneous addition of 1 mM dibutyryl cyclic AMP (DBcAMP), an analogue of cAMP, with 1 mM taurochenodeoxycholic acid (TCDCA) significantly decreased the release of lactate dehydrogenase (LDH) as compared with the case with 1 mM TCDCA alone (7.1 +/- 0.13% of total versus 10.7 +/- 0.3%). In contrast, 0.1 mM papaverine approximately doubled the amount of LDH (22.0 +/- 0.6% of total versus 10.7 +/- 0.3%; P < 0.01). The intracellular content of TCDCA 180 min after the administration of 1 mM TCDCA alone was 20.8 +/- 0.7 nmol/mg protein, that after simultaneous administration of 1 mM DBcAMP, 16.2 +/- 1.0 nmol/mg protein, and that after the simultaneous administration of 0.1 mM papaverine, 38.5 +/- 1.9 nmol/mg protein. A clear correlation between the release of LDH from hepatocytes and the intracellular content of TCDCA was thus observed. When given together with 1 mM taurocholic acid (TCA) or 1 mM tauroursodeoxycholic acid (TUDCA), papaverine exerted little effect on cytotoxicity or intrahepatocytic bile acid content. When cells were bathed in a medium free of bile acid after pretreatment with 1 mM TCDCA and 1 mM DBcAMP, additional exposure to DBcAMP for 30 min significantly stimulated reduction of intracellular TCDCA content (30.2 +/- 0.4% of total versus 44.0 +/- 1.4%).(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Animals; Bile Acids and Salts; Biological Transport; Bucladesine; Cells, Cultured; Liver; Male; Papaverine; Rats; Rats, Sprague-Dawley; Taurochenodeoxycholic Acid; Taurocholic Acid

To determine if ursodeoxycholic acid (UDCA) induces a HCO3(-)-rich hypercholeresis by stimulating HCO3- secretion from bile duct epithelial (BDE) cells, we studied the effect of UDCA, sodium tauroursodeoxycholate (TUDCA), and cholic acid on intracellular pH (pHi) regulation and HCO3- excretion in BDE cells isolated from normal rat liver. Exposure of BDE cells to UDCA (0.5-1.5 mM) produced a dose-dependent initial acidification [from -0.05 to -0.16 pH units (pHu)], which was lower in Krebs-Ringer bicarbonate than in N-2-hydroxyethylpiperazine-N'-2- ethanesulfonic acid (HEPES), because of the higher cell-buffering power in the presence of HCO3-. In contrast, TUDCA (1 mM) had no effect on pHi in either media. BDE acidification induced by UDCA (1.5 mM) in KRB was not inhibited by Cl- depletion excluding activation of Cl(-)-HCO3- exchange. Most BDE cells spontaneously recovered their basal pHi during the UDCA infusion (0.5-1 mM) by a secondary activation of the Na(+)-H+ exchanger (amiloride inhibition of pHi recovery; n = 4), and pHi overshot basal levels by 0.1-0.2 pHu after UDCA withdrawal. The activity of Cl(-)-HCO3- exchange (Cl- removal/readmission maneuver) as well as the activities of Na(+)-H+ exchange and Na(+)-HCO3- symport (NH4Cl acid load in HEPES and KRB, respectively) were unaffected by UDCA (0.5 mM) compared with controls. Cholic acid (1.5 mM), which does not produce a hypercholeresis, also acidified BDE cells in KRB media. These studies indicate that UDCA does not stimulate HCO3- excretion from isolated rat BDE cells but modifies pHi in BDE cells as a weak acid.

Topics: Ammonium Chloride; Animals; Antiporters; Bile Ducts; Chloride-Bicarbonate Antiporters; Chlorides; Cholic Acid; Cholic Acids; Epithelial Cells; Epithelium; Hydrogen-Ion Concentration; In Vitro Techniques; Intracellular Membranes; Rats; Sodium-Hydrogen Exchangers; Taurochenodeoxycholic Acid; Ursodeoxycholic Acid

To assess the effects of tauroursodeoxycholic acid (TUDCA) on bile excretory function, we examined whether TUDCA modulates vesicular exocytosis in the isolated perfused liver of normal rats in the presence of high (1.9 mM) or low (0.19 mM) extracellular Ca++ and in cholestatic rats 24 h after bile duct ligation. In addition, the effects of TUDCA on Ca++ homeostasis were compared in normal and in cholestatic hepatocytes. In the isolated perfused rat liver, TUDCA (25 microM) stimulated a sustained increase in the biliary excretion of horseradish peroxidase, a marker of the vesicular pathway, in the presence of high, but not low extracellular Ca++ or in the cholestatic liver. In contrast, TUDCA stimulated bile flow to the same extent regardless of the concentration of extracellular Ca++ or the presence of cholestasis. In indo-1-loaded hepatocytes, basal cytosolic free Ca++ ([Ca++]i) levels were not different between normal and cholestatic cells. However, in cholestatic cells [Ca++]i increases induced by TUDCA (10 microM) and its 7 alpha-OH epimer taurochenodeoxycholic acid (50 microM) were reduced to 22% and 26%, respectively, compared to normal cells. The impairment of TUDCA-induced [Ca++]i increase in cholestatic cells could be mimicked by exposing normal cells to low extracellular Ca++ (21%) or to the Ca++ channel blocker NiCl2 (23%). These data indicate that (a) dihydroxy bile acid-induced Ca++ entry may be of functional importance in the regulation of hepatocellular vesicular exocytosis, and (b) this Ca++ entry mechanism across the plasma membrane is impaired in cholestatic hepatocytes. We speculate that the beneficial effect of ursodeoxycholic acid in cholestatic liver diseases may be related to the Ca+(+)-dependent stimulation of vesicular exocytosis by its conjugate.

Topics: Acetylglucosaminidase; Animals; Bile; Biomarkers; Calcium; Cells, Cultured; Cholestasis; Cytosol; Exocytosis; Extracellular Space; Horseradish Peroxidase; Kinetics; Liver; Lysosomes; Male; Phenylephrine; Rats; Rats, Sprague-Dawley; Reference Values; Taurochenodeoxycholic Acid; Taurocholic Acid; Vasopressins

Rats which were taurine-deprived through beta-alanine administration and untreated rats were used to elucidate the mechanism of hepatoprotective effects of ursodeoxycholate (UDC). Animals were infused with taurochenodeoxycholate (TCDC, 0.4 mumol.min-1.100 g-1) alone or in combination with tauroursodeoxycholate (TUDC), or with UDC (both 0.6 mumol.min-1.100 g-1) for 2 h. Ursodeoxycholate as well as TUDC prevented severe cholestasis and liver damage induced by TCDC infusion in both untreated and taurine-deprived rat groups. In untreated rats, however, UDC was less effective in hepatoprotection than TUDC as indicated by sequential changes in biliary LDH output during the period of 30 to 120 min (P < 0.05). In rats receiving UDC and TCDC, total biliary output of LDH for 2 h was significantly higher in taurine-deprived rats than that in the control (73.40 +/- 10.10 vs 41.14 +/- 12.56: P < 0.05), suggesting that the difference became greater upon taurine deprivation. In contrast, in rats receiving TUDC and TCDC, the protective effect was comparable for the taurine-deprived and untreated rats. When the animals were infused with UDC and TCDC, taurine-deprived rats exhibited a biliary excretion rate for TUDC half that of control rats (P < 0.05). Furthermore, a highly significant correlation was observed between the biliary excretion rate of TUDC and biliary output of LDH (r = -0.886, P < 0.0001). These results suggest that UDC conjugates, especially TUDC, and not UDC may play a major role in the prevention of cholestasis and liver cell damage caused by TCDC infusion.

Topics: Alkaline Phosphatase; Animals; Bile; Bile Acids and Salts; Cholestasis; L-Lactate Dehydrogenase; Liver; Male; Rats; Rats, Wistar; Taurochenodeoxycholic Acid; Ursodeoxycholic Acid

Little is known about the mechanisms of: 1) biliary phosphatidylcholine (PC) secretion by the hepatocyte, 2) selectivity for biliary 1-palmitoyl-2-linoleoyl-PC (PLPC) secretion, and 3) exclusion of 1-stearoyl-2-arachidonyl-PC (SAPC) from bile. The experiments were designed to determine, in rats, whether selectivity (for PLPC and against SAPC) is influenced by bile acid hydrophobicity or secretion rate. We examined the effects of bile acid depletion and of ileal infusion of taurocholic acid, tauroursodeoxycholic acid, and taurochenodeoxycholic acid. Compared to bile acid depletion, infusion of each bile acid caused PLPC to decrease from 59% of bile PC to 48%, and SAPC to increase from 2.6% to 5%. Bile acid hydrophobicity had no effect on PC selectivity, but selectivity decreased to a moderate degree as total PC secretion increased. To determine whether selectivity is for preformed molecular species, we used a new method to isotopically label four species of hepatic PC. This was done by intravenous injection of PLPC and SAPC labeled in the linoleate (14C) and arachidonate (3H) moieties. Assuming rapid mixing of each PC species in the hepatocyte as supported by the specific activity data, bile SAPC and SLPC were derived entirely from hepatic preformed SAPC and SLPC; bile PLPC was from both preformed PLPC (55%) and an unlabeled input (45%, probably direct secretion of newly synthesized PLPC). In conclusion, the selective composition of bile PC is not related to bile acid hydrophobicity, but is partially lost as secretion increases within the physiologic range.

Topics: Animals; Bile; Bile Acids and Salts; Chemical Phenomena; Chemistry, Physical; Ileum; Liver; Male; Phosphatidylcholines; Rats; Rats, Sprague-Dawley; Taurochenodeoxycholic Acid; Taurocholic Acid

The mechanism of lithocholate-3-O-glucuronide-induced cholestasis is unknown. In this study, we investigated the cholestatic effects of this agent in a congenital hyperbilirubinemic rat, EHBR. We also studied the effects of ursodeoxycholate-3-O-glucuronide and tauroursodeoxycholate on lithocholate-3-O-glucuronide-induced cholestasis in rats. Lithocholate-3-O-glucuronide, administered at the rate of 0.1 mumol/min/100 g for 40 min, a cholestatic dose in control rats, failed to cause cholestasis in EHBR, and biliary lithocholate-3-O-glucuronide excretion was delayed. Biliary concentrations of this agent did not correlate with the severity of cholestasis. Both tauroursodeoxycholate and ursodeoxycholate-3-O-glucuronide, infused at the rate of 0.2 mumol/min/100 g for 120 min, completely inhibited cholestasis induced by lithocholate-3-O-glucuronide administered at the rate of 0.1 mumol/min/100 g for 40 min. Only tauroursodeoxycholate enhanced biliary lithocholate-3-O-glucuronide excretion. These findings indicate that lithocholate-3-O-glucuronide-induced cholestasis is induced by damage at the level of the bile canalicular membrane. Ursodeoxycholate-3-O-glucuronide inhibits this cholestasis, possibly by inhibiting the access of lithocholate-3-O-glucuronide to the bile canalicular membrane.

Topics: Animals; Bile; Cholestasis; Glucuronates; Hyperbilirubinemia, Hereditary; Lithocholic Acid; Liver; Male; Rats; Rats, Sprague-Dawley; Taurochenodeoxycholic Acid; Ursodeoxycholic Acid

In this study, we examined whether ursodeoxycholic acid (UDC) and its taurine conjugate, tauroursodeoxycholic acid (TUDC), given per os, can prevent the cholestasis induced in rats by 17-alpha-ethynyl estradiol (EE) and whether this protection is mediated by choleretic activity or altered plasma membrane composition. EE (5 mg/kg body weight/day for 5 days) markedly reduced bile flow and bile salt secretion without significantly affecting plasma membrane composition and function. Treatment with UDC or TUDC (100, 150 or 200 (TUDC only) mumol/100 g body weight/day for 5 days) did not significantly modify bile flow, but the bile salt secretion rate increased in a dose-dependent manner. UDC was the main biliary bile acid secreted in groups given higher doses of UDC or TUDC. At these dose levels, bile acid treatment did not affect plasma membrane fluidity as assessed by fluorescence anisotropy, the cholesterol/phospholipid molar ratio as well as Na+K(+)- and Mg(++)-ATPase activities. The highest dose of UDC and TUDC prevented the reduction of both bile flow and bile salt secretion induced by EE, re-establishing these parameters to the values of the corresponding control for the UDC group. In conclusion, UDC and TUDC, given per os, improve EE-induced cholestasis, an effect that cannot be attributed to choleretic activity or altered plasma membrane composition.

Topics: Administration, Oral; Animals; Bile; Cell Membrane; Cholestasis, Intrahepatic; Ethinyl Estradiol; Fluorescence Polarization; Isomerism; Liver; Male; Membrane Fluidity; Rats; Rats, Sprague-Dawley; Taurochenodeoxycholic Acid; Ursodeoxycholic Acid

Cytoprotection by tauroursodeoxycholic acid and tauro-beta-muricholic acid against taurochenodeoxycholic acid-induced toxicity was examined with reference to intracellular bile acid content in primary cultured rat hepatocytes. In comparison with levels in the group administered taurochenodeoxycholic acid 1 mmol/L alone, lactate dehydrogenase levels in the culture medium decreased significantly in groups simultaneously administered taurochenodeoxycholic acid 1 mmol/L and tauroursodeoxycholic acid 0.5 to 2 mmol/L or tauro-beta-muricholic acid. Results of the trypan blue uptake test indicated that the lactate dehydrogenase release was indeed caused by cell damage. After the administration of tauroursodeoxycholic acid 2 mmol/L or tauro-beta-muricholic acid 2 mmol/L, intracellular taurochenodeoxycholic acid content was consistently reduced to half of that after administration of taurochenodeoxycholic acid alone. Simultaneous administration of dibutyl cyclic AMP also reduced intracellular taurochenodeoxycholic acid content and lactate dehydrogenase release. Being rinsed with tauroursodeoxycholic acid and tauro-beta-muricholic acid after being precultured in taurochenodeoxycholic acid 1 mmol/L also markedly reduced their taurochenodeoxycholic acid content. Taurocholic acid caused limited reduction of intracellular taurochenodeoxycholic acid but not suppression of lactate dehydrogenase release. Taurodehydrocholic acid showed no reduction of taurochenodeoxycholic acid content and no decrease of lactate dehydrogenase release. Although only small amounts of tauroursodeoxycholic acid or tauro-beta-muricholic acid were found to accumulate in hepatocytes, taurocholic acid increased as if replacing taurochenodeoxycholic acid. The results suggest that tauroursodeoxycholic acid or tauro-beta-muricholic acid may exert cytoprotective effects by lowering intracellular taurochenodeoxycholic acid levels associated with their optimal hydrophilicity.

Topics: Animals; Bucladesine; Cells, Cultured; Intracellular Membranes; L-Lactate Dehydrogenase; Liver; Rats; Taurochenodeoxycholic Acid; Taurocholic Acid

Tauroursodeoxycholic acid (TUDCA) is of potential benefit in cholestatic disorders. However, the effects of TUDCA on cytosolic free calcium [(Ca2+)i], which regulates hepatocyte secretion, are unknown.. The effect of TUDCA on (Ca2+)i was investigated in groups of isolated rat hepatocytes by microspectrofluorometry and in single cells by confocal line scanning microscopy.. Administration of TUDCA (5-50 mumol/L) induced a nearly fourfold increase of basal levels of (Ca2+)i. After a 15 minute treatment period, the TUDCA (10 mumol/L)-induced change in (Ca2+)i was higher than that of other mono-, di-, and trihydroxy bile acids at equimolar concentrations. Pretreatment with TUDCA (10 mumol/L) markedly reduced or abolished increases in (Ca2+)i induced by phenylephrine (1 mumol/L), the microsomal Ca(2+)-translocase inhibitor 2,5-di-(tert-butyl)-1,4-benzohydroquinone (25 mumol/L), or taurolithocholic acid (10-25 mumol/L). In Ca(2+)-free medium, TUDCA caused only a reduced and transient increase in (Ca2+)i. TUDCA (10 mumol/L) induced Ca2+ oscillations in all single cells that responded. However, levels of inositol-1,4,5-trisphosphate (IP3) in hepatocytes were not increased by treatment with TUDCA (10 mumol/L).. TUDCA at physiological concentrations potently modulates (Ca2+)i signals in hepatocytes by (1) mobilizing microsomal IP3-sensitive Ca2+ stores by an IP3-independent mechanism, (2) initiating Ca2+ oscillations, and (3) inducing influx of extracellular Ca2+.

Topics: Animals; Calcium; Cytosol; Glucose; In Vitro Techniques; Inositol 1,4,5-Trisphosphate; Liver; Male; Rats; Rats, Sprague-Dawley; Signal Transduction; Taurochenodeoxycholic Acid

The effects of bile acids on cytosolic free calcium ([Ca2+]i) were studied in single isolated rat hepatocyte couplets using a scanning laser cytometer and the fluorescent dye, indo-1. Cholestatic bile acids, chenodeoxycholate (CDC) and taurolithocholate (TLC) increased [Ca2+]i in a dose-dependent manner. Choleretic bile acids, tauroursodeoxycholate (TUDC) and taurocholate (TC), did not induce any change in [Ca2+]i except TC at very high doses. Treatment with TUDC added concomitantly with CDC or TLC significantly decreased the rise in [Ca2+]i induced by bile acids. These results, obtained with a polarized hepatocyte model that secretes bile, confirmed that cholestatic bile acids increase [Ca2+]i and showed that TUDC inhibits this phenomenon. These data are in agreement with a key role of intracellular calcium in cholestasis.

Topics: Animals; Bile Acids and Salts; Calcium; Chenodeoxycholic Acid; In Vitro Techniques; Liver; Male; Models, Biological; Rats; Rats, Sprague-Dawley; Taurochenodeoxycholic Acid; Taurolithocholic Acid; Vasopressins

The effect of the co-infusion of ursodeoxycholate and its taurine conjugate, 3-O-glucuronide and 3,7-disulfate on estradiol-17 beta-glucuronide-induced cholestasis was examined. Estradiol-17 beta-glucuronide was intravenously administered to bile-drained rats at a rate of 0.075 mumol/min/100 g for 20 min. Co-infusion of ursodeoxycholate and its conjugates was simultaneously begun at a rate of 0.2 mumol/min/100 g and continued for 120 min. Ursodeoxycholate failed to improve and tauroursodeoxycholate only partially improved estradiol-17 beta-glucuronide-induced cholestasis between 20 and 40 min, although both bile acids increased bile flow after 80 min. Tauroursodeoxycholate increased biliary estradiol-17 beta-glucuronide excretion. Ursodeoxycholate-3-O-glucuronide completely inhibited cholestasis induced by estradiol-17 beta-glucuronide without changing biliary estradiol-17 beta-glucuronide excretion. Although ursodeoxycholate-3,7-disulfate had only a minor effect on cholestasis, it increased biliary excretion of estradiol-17 beta-glucuronide. In the Eizai hyperbilirubinuria rat (EHBR), a hyperbilirubinemic mutant Sprague-Dawley rat, the same dose of estradiol-17 beta-glucuronide failed to induce cholestasis with a marked delay in biliary excretion of estradiol-17 beta-glucuronide. In summary, ursodeoxycholate-3-O-glucuronide is more effective than tauroursodeoxycholate in inhibiting estradiol-17 beta-glucuronide-induced cholestasis and ursodoexycholate-3,7-disulfate had little effect. However, the unexpected effects of ursodeoxycholate-3-O-glucuronide and 3,7-disulfate on excretion of estradiol-17 beta-glucuronide suggest that the interaction of these anions at the canalicular membrane is complicated, with interaction occurring at more than two pathways of the biliary excretion of these anions.

Topics: Animals; Bile; Cholagogues and Choleretics; Cholestasis; Estradiol; Hyperbilirubinemia, Hereditary; Isomerism; Male; Rats; Rats, Mutant Strains; Taurochenodeoxycholic Acid; Ursodeoxycholic Acid

Topics: Animals; Bile; Cholagogues and Choleretics; Cholestasis; Humans; Liver Cirrhosis, Biliary; Rats; Taurochenodeoxycholic Acid

In order to cast light on the anti-cholestatic and cytoprotective properties of ursodeoxycholic acid (UDCA), intrahepatic transport and secretion of bile salts and biliary phospholipids were investigated by using isolated perfused livers from colchicine-pretreated rats. Administration of taurocholic acid (TCA) after colchicine pretreatment induced marked cholestasis. Tauroursodeoxycholic acid (TUDCA) treatment, in contrast, was associated with maintenance of bile flow, with excretion rates of bile acids and phospholipids similar to those in control animals. Furthermore, TCA-induced cholestasis in colchicine-treated rat livers was clearly decreased by co-administration of TUDCA. Although simultaneous addition of UDCA also showed slight improvement, with or without taurine pre-treatment, biliary bile-salt analysis also showed that cholestasis was markedly remitted as the excretion of taurine-conjugated UDCA was increased. The results suggest that the cytoprotective and anti-cholestatic effects of TUDCA may be linked to action at the intrahepatocyte level, represented by mild detergent effects on organelle lipids and preservation of intracellular transport even under microtubule-dysfunctional conditions. In addition, it was indicated that cytoprotective effects of UDCA may also be exerted after its conjugation with taurine inside hepatocytes.

Topics: Animals; Aspartate Aminotransferases; Bile; Cholestasis; Colchicine; gamma-Glutamyltransferase; Male; Microtubules; Rats; Rats, Inbred Strains; Secretory Rate; Taurochenodeoxycholic Acid; Taurocholic Acid; Ursodeoxycholic Acid

The interaction between cell volume and taurocholate excretion into bile was studied in isolated perfused rat liver. Cell swelling due to hypo-osmotic exposure, addition of amino acids or insulin stimulated taurocholate excretion into bile and bile flow, whereas hyperosmotic cell shrinkage inhibited these. These effects were explained by changes in Vmax of taurocholate excretion into bile: Vmax. increased from about 300 to 700 nmol/min per g after cell swelling by 12-15% caused by either hypo-osmotic exposure or addition of amino acids under normo-osmotic conditions. Steady-state taurocholate excretion into bile was not affected when the influent K+ concentration was increased from 6 to 46 mM or decreased to 1 mM with iso-osmoticity being maintained by corresponding changes in the influent Na+ concentration. Replacement of 40 mM-NaCl by 80 mM-sucrose decreased taurocholate excretion into bile by about 70%; subsequent hypo-osmotic exposure by omission of sucrose increased taurocholate excretion to 160%. Only minor, statistically insignificant, effects of aniso-osmotic cell volume changes on the appearance of bolus-injected horseradish peroxidase in bile were observed. Taurocholate (400 microM) exhibited a cholestatic effect during hyperosmotic cell shrinkage, but not during hypo-osmotic cell swelling. Both taurocholate and tauroursodeoxycholate increased liver cell volume. Tauroursodeoxycholate stimulated taurocholate (100 microM) excretion into bile. This stimulatory effect was strongly dependent on the extent of tauroursodeoxycholate-induced cell swelling. During continuous infusion of taurocholate (100 microM) further addition of tauroursodeoxycholate at concentrations of 20, 50 and 100 microM increased cell volume by 10, 8 and 2% respectively, in parallel with a stimulation of taurocholate excretion into bile by 29, 27 and 9% respectively. There was a close relationship between the extent of cell volume changes and taurocholate excretion into bile, regardless of whether cell volume was modified by tauroursodeoxycholate, amino acids or aniso-osmotic exposure. The data suggest that: (i) liver cell volume is one important factor determining bile flow and biliary taurocholate excretion; (ii) swelling-induced stimulation of taurocholate excretion into bile is probably not explained by alterations of the membrane potential; (iii) bile acids modulate liver cell volume; (iv) taurocholate-induced cholestasis may depend on cell volume; (v) stimulation of tauroch

Topics: Amino Acids; Animals; Bile Acids and Salts; Cell Size; Insulin; Intercellular Junctions; Liver; Male; Permeability; Rats; Rats, Wistar; Taurochenodeoxycholic Acid; Taurocholic Acid; Water-Electrolyte Balance

The present study has demonstrated that tauroursodeoxycholate (TUDC), but not taurocholate, can reverse chlorpromazine (CPZ)-induced cholestasis in the isolated perfused rat liver. At an infusion rate of 1.5 mumol/min, TUDC led to restoration of bile flow in the perfused rat liver made cholestatic by the addition of 250 microM CPZ. This reversal was accompanied by an increased excretion of CPZ and its metabolites. A higher infusion rate of 5.0 mumols TUDC/min, however, led to only a transient increase in bile flow and to no increase in CPZ excretion. In contrast to the effects of TUDC, infusion of taurocholate led to an exacerbation of CPZ-induced cholestasis. The differences in the efficacy of the two bile salts may be due to their relative detergent (hydrophobic) properties.

Topics: Animals; Bile; Chlorpromazine; Cholestasis; In Vitro Techniques; Isomerism; Kinetics; Liver; Male; Perfusion; Rats; Rats, Inbred Strains; Taurochenodeoxycholic Acid; Taurocholic Acid; Time Factors

Chlorpromazine at a concentration of 250 microM and estradiol-17 beta-D-glucuronide at 17.5 microM on infusion led to a sharp reduction in bile flow by the in vitro perfused rat liver. This was accompanied by fragmentation and a loss of canalicular microvilli, dilatation of canaliculi, and thickening of pericanalicular ectoplasm. Less prominent were the smooth endoplasmic reticulum dilatation, lysosomal lamination, and the appearance of amorphous bile in hepatocyte cytoplasm. The bile flow and electron microscopy appearance were restored to normal by infusion of tauroursodeoxycholate in a concentration of 5 mumols/min for the estradiol-17 beta-D-glucuronide-induced cholestasis and 1.5 mumol/min for the chlorpromazine-induced cholestasis. Changes in ultrastructure paralleled changes in bile flow. These observations demonstrate the feasibility of electron microscopy studies on the perfused liver, and the rapidity with which cholestatic changes appear.

Topics: Animals; Bile; Chlorpromazine; Cholestasis; Estradiol; In Vitro Techniques; Kinetics; Liver; Microscopy, Electron; Perfusion; Rats; Taurochenodeoxycholic Acid; Time Factors

We investigated whether stimulation of bile flow by taurocholic acid (TCA), ursodeoxycholic acid (UDCA) or its taurine conjugate (TUDCA) could protect the liver from ischemia-reperfusion injury. The isolated perfused rat liver model was used. In livers perfused without bile acids (n = 8), 60 min of ischemia induced a significant reduction in bile flow and in portal flow, together with a marked increase in LDH, AST and uric acid release in the perfusate. These alterations were maximal at the beginning of reperfusion. In livers perfused with TCA (n = 6), UDCA (n = 7) or TUDCA (n = 6), bile flow was significantly increased as compared to controls during the pre-ischemic phase, as well as during the reperfusion phase. However, no significant improvement was observed in any of the biochemical, hemodynamic or histologic parameters studied. The results show that stimulation of bile flow either by TCA, UDCA or TUDCA does not reduce ischemia-reperfusion liver injury. Furthermore, the results do not provide evidence for a cytoprotective effect of UDCA or TUDCA in this model of liver injury.

Topics: Animals; Aspartate Aminotransferases; Bile; Ischemia; Isomerism; L-Lactate Dehydrogenase; Liver Circulation; Male; Perfusion; Rats; Rats, Inbred Strains; Reperfusion Injury; Taurochenodeoxycholic Acid; Taurocholic Acid; Uric Acid; Ursodeoxycholic Acid

We measured hepatic cholesterol 7 alpha-hydroxylase activity, mass, and catalytic efficiency (activity/unit mass) in bile fistula rats infused intraduodenally with taurocholate and its 7 beta-hydroxy epimer, tauroursocholate, with or without mevalonolactone to supply newly synthesized cholesterol. Enzyme activity was measured by an isotope incorporation assay and enzyme mass by densitometric scanning of immunoblots using rabbit anti-rat liver cholesterol 7 alpha-hydroxylase antisera. Cholesterol 7 alpha-hydroxylase activity increased 6-fold, enzyme mass 34%, and catalytic efficiency 5-fold after interruption of the enterohepatic circulation for 48 h. When taurocholate was infused to the bile acid-depleted animals at a rate equivalent to the hepatic bile acid flux (27 mumol/100-g rat/h), cholesterol 7 alpha-hydroxylase activity and enzyme mass declined 60 and 61%, respectively. Tauroursocholate did not significantly decrease cholesterol 7 alpha-hydroxylase activity, mass and catalytic efficiency. The administration of mevalonolactone, which is converted to cholesterol, modestly increased cholesterol 7 alpha-hydroxylase activity and enzyme mass in the bile acid-depleted rats. However, when taurocholate was infused together with mevalonolactone, cholesterol 7 alpha-hydroxylase activity and catalytic efficiency were markedly depressed while enzyme mass did not change as compared with bile acid-depleted rats. These results show that (a) hepatic bile acid depletion increases bile acid synthesis mainly by activating cholesterol 7 alpha-hydroxylase with only a small rise in enzyme mass, (b) replacement with taurocholate for 24 h decreases both cholesterol 7 alpha-hydroxylase activity and mass proportionally, (c) when cholesterol is available (mevalonolactone supplementation), the infusion of taurocholate results in the formation of a catalytically less active cholesterol 7 alpha-hydroxylase, and (d) tauroursocholate, the 7 beta-hydroxy epimer of taurocholate, does not inhibit cholesterol 7 alpha-hydroxylase. Thus, bile acid synthesis is modulated by the catalytic efficiency and mass of cholesterol 7 alpha-hydroxylase. The enterohepatic flux of 7 alpha-hydroxylated bile acids and the formation of hepatic cholesterol apparently control cholesterol 7 alpha-hydroxylase by different mechanisms.

Topics: Animals; Bile Acids and Salts; Blotting, Western; Catalysis; Cholesterol; Cholesterol 7-alpha-Hydroxylase; Hydroxylation; Male; Mevalonic Acid; Microsomes, Liver; Rats; Rats, Inbred Strains; Taurochenodeoxycholic Acid; Taurocholic Acid

A single intravenous injection of [14C]taurocholate was followed up in blood and bile of rats submitted to steady intravenous infusions of taurocholate (TC) at rates of 0.0, 0.5, 1.0, and 1.5 mumol.min-1.100 g body wt-1 for at least 30 min. The transport rate constants and the amounts of TC in different compartments were estimated by weighted least-squares adjustment of a six-compartment model to the experimental data (3 compartments for TC distribution in blood, 2 compartments for liver, and 1 compartment for sinusoidal blood space). The saturation of the TC excretion rate was reached at 0.8 mumol.min-1.100 g body wt-1. It was characterized by a decrease of both the uptake and excretion rate constants, by an increase of the ratio of the amounts of TC in the two intrahepatic compartments (H'/H), and by an intrahepatic TC concentration of approximately 2 mM. When tauroursodeoxycholate (TUDC) was infused at a rate of 0.5 mumol.min-1.100 g body wt-1 together with TC at a rate of 1.5 mumol.min-1.100 g body wt-1, the TC excretion rate increased to 1.2 mumol.min-1.100 g body wt-1, and the excretion rate constant and H'/H decreased toward control values. These results support the hypothesis that the saturation of the transport of TC is due to TC hepatotoxicity and can be reduced by TUDC. Michaelis-Menten parameters, derived from saturation curves for both uptake and excretion steps, closely matched earlier results, thus confirming the good descriptive capacity of the model.

Topics: Animals; Bile; Biological Transport; Female; Infusions, Intravenous; Kinetics; Liver; Models, Biological; Rats; Rats, Inbred Strains; Taurochenodeoxycholic Acid; Taurocholic Acid

Ursodeoxycholate (UDC) and tauroursodeoxycholate (TUDC) have been reported to be protective against liver injury induced by other bile salts. UDC also has been shown to be effective against refluxed bile-induced gastritis after gastric surgery. However the mechanism of the therapeutic effect of UDC on gastric mucosa has not been known. In the present study, cytoprotective actions of UDC and TUDC against chenodeoxycholate (CDC)-induced gastric injury were investigated using rabbit gastric cell cultures without systemic factors. Rabbit gastric mucosal cells were cultured after the isolation of rabbit gastric cells with collagenase and ethylenediaminetetraacetic acid. Cytotoxicity was quantified by measuring 51Cr release from prelabeled cells and MTT assay. Prostaglandin (PG) E2 was assayed by radioimmunoassay. Concentrations of CDC greater than 0.5 mM or UDC greater than 5 mM caused cellular damage and increased 51Cr release in a dose-dependent and time-dependent fashion, while TUDC up to 10 mM did not. TUDC, but not UDC, showed a significant decrease of CDC (1.5 mM)-induced 51Cr release dose dependently. The protective effect of TUDC against CDC-induced damage was confirmed by MTT assay. On phase-contrast microscopy, disruption of monolayers induced by CDC (1.5 mM) was clearly protected by TUDC (10 mM). Free radical scavengers (500 units/ml of superoxide dismutase, 300 units/ml of catalase, and 100 mM of dimethyl sulfoxide) or a calcium blocker (10(-7)-10(-5) M verapamil) did not show significant protection against CDC-induced damage. Deprivation of Ca2+ in the media did not affect CDC-induced damage. Thus free radicals or Ca2+ might not be involved in the cell toxicity of CDC.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Animals; Bile Acids and Salts; Calcium; Cells, Cultured; Chenodeoxycholic Acid; Dinoprostone; Dose-Response Relationship, Drug; Female; Free Radicals; Gastric Mucosa; Indomethacin; Isomerism; Male; Rabbits; Taurochenodeoxycholic Acid; Verapamil

The effect of the cytoprotective bile acid tauroursodeoxycholic acid (TUDCA) on basal cytosolic free Ca++ (Ca++)i and receptor-mediated (Ca++)i increase was studied in human polymorphonuclear neutrophils using the fluorescent dye quin2. Basal levels of (Ca++)i were 96 +/- 6 nmol/l (mean +/- SEM, n = 48). TUDCA and its cytotoxic epimer taurochenodeoxycholic acid (TCDCA) at 500 mumols/l increased (Ca++)i by 31 +/- 12 and 27 +/- 7 nmol/l, respectively (n = 6, p less than 0.05). Stimulation of neutrophils with the chemotactic tripeptide N-formyl-methionyl-leucyl-phenylalanine (FMLP; 10(-7) mol/l) induced a (Ca++)i increase of 200 +/- 32 nmol/l which was inhibited after preincubation with TUDCA (500 mumols/l) or TUDCA + TCDCA (500 mumols/l, each) by 60.1% and 59.5%, respectively, but not with TCDCA (500 mumols/l) alone. The inhibitory effect of TUDCA on FMLP-induced (Ca++)i increase was strongly concentration-dependent and was nearly complete at 1000 mumols/l. Since (Ca++)i is discussed as a mediator of cellular injury we hypothesize that TUDCA may exert its protective effects at least partly via inhibition of (Ca++)i-mediated cytotoxic processes.

Topics: Calcium; Cytosol; Humans; In Vitro Techniques; Isomerism; Kinetics; N-Formylmethionine Leucyl-Phenylalanine; Neutrophils; Taurochenodeoxycholic Acid

Continuous intravenous infusion of taurochenodeoxycholate at a rate of 0.4 mumol.min-1.100 gm-1 for only 30 min in rats caused threefold to tenfold greater release of proteins (alkaline phosphatase, lactate dehydrogenase and albumin) into bile in comparison with animals infused with tauroursodeoxycholate at much higher rates (1.8 mumol.min-1.100 gm-1) for 2 hr. The simultaneous infusion of tauroursodeoxycholate and taurochenodeoxycholate (0.6 and 0.4 mumol.min-1.100 gm-1, respectively) for 2 hr prevented the marked biochemical changes in the bile induced by taurochenodeoxycholate for 15 to 60 min exhibited significantly more necrotic hepatocytes, especially in zone 1, in comparison with animals infused with tauroursodeoxycholate or a combination of taurochenodeoxycholate and tauroursodeoxycholate. A good correlation was observed between biochemical and morphological indices of bile acid-induced hepatocyte injury. These data suggest that (a) primary events induced by the acute infusion of toxic bile salts responsible for cholestasis include zone 1 hepatocellular necrosis and (b) this can be prevented by the simultaneous infusion of tauroursodeoxycholate.

Topics: Animals; Bile; Bile Acids and Salts; Liver; Male; Necrosis; Proteins; Rats; Rats, Inbred Strains; Taurochenodeoxycholic Acid; Taurocholic Acid

Ursodeoxycholate-induced bicarbonate-rich hypercholeresis was studied in isolated in situ forward- or backward-perfused rat livers. Both spontaneous bile flow and bile acid secretion were similar regardless of the direction of the perfusion. The choleretic effect of tauroursodeoxycholate infusion (400 nmol.min-1.100 g-1 body weight) was not significantly different in forward- or backward-perfused livers either. Ursodeoxycholate infusions at low rate (800 nmol.min-1.100 g-1 body weight) induced similar bile flow, bile acid output and bicarbonate output in both forward- and backward-perfused livers. Net ursodeoxycholate uptake, measured as [14C]ursodeoxycholate uptake over the bile acid infusion period (30 min), was not significantly different during forward- or backward-perfusion (4.8 and 5.1 mumol/g liver, respectively); i.e., approx. 67% of infused dose (approximately 7.5 mumol/g liver per 30 min). A 2-fold increase in the dose of ursodeoxycholate infusion (1600 nmol.min-1.100 g-1 b.wt.) induced additional enhancement in both bile flow and bicarbonate biliary secretion, but not in bile acid uptake or output, in forward-perfused livers. Moreover, infusion of the same dose of ursodeoxycholate to backward-perfused livers had a significantly lower choleretic effect (-29%, p less than 0.001) even though ursodeoxycholate uptake and biliary output were similar regardless of perfusion direction. Net ursodeoxycholate uptake, was only 2.4 mumol/g liver; i.e., approx. 16% of infused dose (approximately 15 mumol/g liver per 30 min). These findings indicate that a process related with the hepatic microanatomy may be involved in the hypercholeretic response to ursodeoxycholate.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Animals; Bicarbonates; Bile; Liver; Male; Perfusion; Rats; Rats, Inbred Strains; Taurochenodeoxycholic Acid; Ursodeoxycholic Acid

Cholestasis and enhanced biliary leakage of proteins such as lactate dehydrogenase (LDH) and albumin are known to be induced by infusions of relatively toxic bile salts such as taurocholate (TC) and taurochenodeoxycholate (TCDC). Tauroursodeoxycholate (TUDC) was previously shown to prevent these bile abnormalities when simultaneously infused (1-5). In the present study, we examined whether tauro beta-muricholate (T beta-MC) has a similar effect. The enhanced biliary excretion of LDH and albumin induced by the infusion of TCDC at a rate of 0.4 mumol/min/100 g was markedly prevented by the simultaneous infusion of T beta-MC or TUDC at a rate one-fourth that of TCDC. Increased LDH level in plasma and hemolysis caused by the infusion of TCDC were also reduced by either T beta-MC or TUDC. These results indicate that T beta-MC has a preventive effect on TCDC-induced hepatobiliary changes, which is as efficient as that of TUDC as shown previously, suggesting that the 7 beta-hydroxy group is important for this hepatoprotective effect. Furthermore, our results suggest that beta-muricholic acid may also have clinical value since current reports demonstrate a beneficial effect of ursodeoxycholic acid on a variety of cholestatic conditions, including primary biliary cirrhosis.

Topics: Animals; Bile; Cholestasis; Cholic Acids; L-Lactate Dehydrogenase; Liver; Male; Rats; Rats, Inbred Strains; Taurochenodeoxycholic Acid

This study was designed to test the hypothesis that increasing the infusion rate of bile salts could overcome drug-induced cholestasis. Cholestasis was induced by administration of 17.5 mumol/L estradiol-17 beta-D-glucuronide during the infusion of taurocholate, tauroursodeoxycholate or dehydrocholate at 20 nmol/min/gm liver. After 30 min, a bolus of 10 mumol of the bile salts was added to the perfusate, and the infusion rate of each bile salt was increased. Taurocholate at a rate of 62 or 125 nmol/min/gm liver, caused a prompt dose-dependent increase of the depressed bile flow and bile salt excretion. A higher rate of taurocholate infusion (180 nmol/min/gm liver) was less effective than either the 62 or 125 rate in increasing bile flow. Infusion of tauroursodeoxycholate at 250 or 390 nmol/min/gm liver also led to a dose-dependent recovery. Further increase of tauroursodeoxycholate infusion rate of 580 nmol/min/gm liver did not provide any additional recovery in bile flow. Dehydrocholate, at rates of 62 or 125 nmol/min/gm liver, gave only a slight enhancement of bile flow. Both taurocholate and tauroursodeoxycholate caused a marked removal of the estradiol-17 beta-D-glucuronide, which had accumulated in the liver. At lower taurocholate infusion rates, the estradiol-17 beta-D-glucuronide was excreted mainly in the bile. At the highest rate, however, biliary excretion of estradiol-17 beta-D-glucuronide declined significantly, and a marked back-efflux of the estrogen into the perfusate was noted. In contrast, tauroursodeoxycholate led to enhanced biliary estradiol-17 beta-D-glucuronide excretion at all increased tauroursodeoxycholate infusion rates and to only a small increase in back-efflux of estradiol-17 beta-D-glucuronide at the two highest tauroursodeoxycholate infusion rates.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Animals; Bile; Bile Acids and Salts; Biological Transport; Cholagogues and Choleretics; Cholestasis; Dehydrocholic Acid; Estradiol; Male; Rats; Rats, Inbred Strains; Sucrose; Taurochenodeoxycholic Acid; Taurocholic Acid

Ursodeoxycholate has been advocated for the treatment of cholestatic liver diseases. The coinfusion of tauroursodeoxycholate with taurolithocholate in the perfused rat liver completely prevented the decrease of bile flow and the increase of oxygen uptake found with taurolithocholate only. Bile flow and bile salt secretion were increased with the coinfusion of both bile acids as compared with the infusion of tauroursodeoxycholate only (+4.30 microliters/g liver per 30 min) with 16 and 32 mumol/l tauroursodeoxycholate (+1.55 microliters/g liver per 30 min with 80 and 160 mumol/l). Morphological examination revealed a 50% decrease of the number of necrotic cells in the periportal area. Tauroursodeoxycholate did not inhibit the uptake of taurolithocholate, but increased its transcellular passage and biotransformation. Thus, tauroursodeoxycholate prevents taurolithocholate-induced cholestasis and liver cell toxicity probably by an intracellular mechanism.

Topics: Animals; Chenodeoxycholic Acid; Cholestasis; Lithocholic Acid; Liver; Rats; Taurochenodeoxycholic Acid; Taurolithocholic Acid

The permeability of the biliary epithelium to [14C]ursodeoxycholic acid (UDCA), a hypercholeretic bile acid, was compared to that of the 14C-labeled nonhypercholeretic bile acids cholic acid (CA), taurocholic acid (TCA), and tauroursodeoxycholic acid (TUDCA) by means of anterograde intrabiliary infusions and retrograde intrabiliary injections in the anesthetized rat. Anterograde intrabiliary infusions were performed by perfusing an isolated segment of common bile duct in vivo. After anterograde intrabiliary infusions, the fraction of unrecovered UDCA (that had presumably been absorbed from the biliary lumen) was 11.03 +/- 1.03 (SE)% (n = 6) of the administered dose. It was significantly higher than that of TUDCA (1.25 +/- 0.27%; n = 5; P less than 0.01), CA (2.62 +/- 0.43%; n = 4; P less than 0.01), and TCA (2.57 +/- 0.79%; n = 6; P less than 0.01). In separate experiments, bile was collected from the common bile duct and from the left hepatic duct. UDCA recovered from the left hepatic duct was found in the conjugated form, indicating that, after absorption in the common bile duct, it had been conjugated by the hepatocyte and secreted into bile. After retrograde intrabiliary injections of UDCA and CA, the cumulative percentages of recovered radioactivity were not significantly different (84.50 +/- 2.65 and 87.33 +/- 1.80%, respectively); however, peak recovery of UDCA was significantly delayed compared with that of CA. Moreover, UDCA was recovered mostly in the conjugated form, while CA was recovered mostly in the unconjugated form. These results suggest that, in the rat, UDCA is significantly more absorbed by the biliary tree than CA, TUDCA, and TCA. They support the hypothesis that UDCA undergoes a cholehepatic circulation.

Topics: Absorption; Animals; Bile; Bile Ducts; Cell Membrane Permeability; Cholic Acid; Cholic Acids; Common Bile Duct; Deoxycholic Acid; Epithelium; Glucose; Kinetics; Liver; Male; Microscopy, Electron; Rats; Rats, Inbred Strains; Sucrose; Taurochenodeoxycholic Acid; Taurocholic Acid; Ursodeoxycholic Acid

The hepatic extraction of unconjugated and taurine-conjugated bile acids, provided with different hydrophilicity values, has been measured in the perfused rat liver, in order to evaluate the role of the bile acid structure and bile acid hydrophilicity on their uptake by the liver. Ursocholic, cholic, ursodeoxycholic and chenodeoxycholic acids, free and taurine-conjugated, were injected into the portal vein in dose response studies, using a nonrecirculating perfusion system. For all of the bile acids, the uptake process showed saturation. In addition, a nonsaturable component was apparent in bile acids provided with the lowest hydrophilicity values, as expressed by the lowest values of the water to octanol partition coefficient. The maximum uptake velocity increased with increasing values of the partition coefficient, which in turn were associated with 7-OH alpha to beta epimerization, the presence of 12-OH in alpha position and taurine conjugation. The ratio of maximum uptake velocity to Km (Km being the half-saturation constant) appeared to be markedly increased by taurine conjugation and by 7-OH alpha to beta epimerization, whereas it was reduced by the presence of 12-OH in alpha position.

Topics: Animals; Bile Acids and Salts; Cholic Acid; Cholic Acids; Hydroxylation; Isomerism; Liver; Male; Rats; Rats, Inbred Strains; Structure-Activity Relationship; Taurochenodeoxycholic Acid; Taurocholic Acid

To establish whether the calcium-binding capacities of the bile salts play an essential role in their stimulatory effects on biliary calcium secretion, we compared (1) the effects of tauro- and glycoconjugates of ursodeoxycholate (TUDC-GUDC) and cholate (TC-GC) on biliary calcium in bile fistula rats, and (2) the in vitro calcium-binding capacities of mixed micelles containing the same bile salts. The increase of biliary calcium depended on the infused bile salt in the following order: GUDC greater than GC = TUDC greater than GC). The same order was obtained in vitro, so that there was a linear relationship between the slopes of the [Ca] vs. [bile salts] regression lines in vivo and the binding percentages of the four bile salts. Biliary ionized calcium concentration was almost independent of bile salt concentration. However, hepatic bile was supersaturated with calcium carbonate in the presence of the four bile salts. Our results suggest that biliary calcium concentration increases in relation to the calcium-binding capacity of the various bile acids so that ionized biliary calcium remains in equilibrium with plasma. As a result, bile saturation with calcium is almost completely independent of bile salt secretion.

Topics: Animals; Bile; Bile Acids and Salts; Calcium; Calcium Carbonate; Glycocholic Acid; Male; Rats; Rats, Inbred Strains; Taurochenodeoxycholic Acid; Taurocholic Acid; Ursodeoxycholic Acid

Biliary secretory pressure represents the force generated to deliver bile through the biliary system. Bile acid-induced toxicity may decrease canalicular bile formation and (or) induce back diffusion causing cholestasis. To determine if biliary secretory pressure is a sensitive indicator of bile toxicity, taurocholate was compared with a less cytotoxic bile acid, tauroursodeoxycholate. In fasted male Sprague-Dawley rats, the common bile duct was cannulated and the endogenous bile salt pool was removed by enteroclysis. Taurocholate (n = 35) or tauroursodeoxycholate (n = 35) in saline was infused for 1 h. Maximal biliary secretory pressure was then measured by attaching the biliary cannula to a column monometer and recording the maximum height to which bile rose. With taurocholate administration, bile flow and bile salt secretion linearly rose to a maximum infusion of 0.5 mumol/(min.g liver), above which hemolysis and death occurred. In contrast, tauroursodeoxycholate could be infused at higher rates with bile salt secretion plateauing at 1.25 mumol/(min.g liver] Both had similar choleretic potencies. Mean biliary secretory pressure at low (less than 0.15 mumol/(min.g liver] infusions was lower with taurocholate (22.5 cm bile) than tauroursodeoxycholate (25.2 cm). Further, increasing the taurocholate infusion decreased the biliary secretory pressure; yet for taurousodeoxycholate, pressure remained unchanged even at higher infusions. Thus, taurocholate but not tauroursodeoxycholate decreases biliary secretory pressure at high infusion rates, likely a reflection of its toxicity to the hepatobiliary epithelium.

Topics: Animals; Bile; Bile Acids and Salts; Chenodeoxycholic Acid; Male; Rats; Rats, Inbred Strains; Reference Values; Taurochenodeoxycholic Acid; Taurocholic Acid

Topics: Chemical Phenomena; Chemistry, Physical; Chenodeoxycholic Acid; Taurochenodeoxycholic Acid

This study reports the effect of short-term tauroursodeoxycholic acid (TUDCA) and of TUDCA with addition of taurine on the lipid composition of gallbladder bile, on cholesterol and bile acid synthesis and intestinal excretion, in the female hamsters. After either one or two weeks, the percentage of ursodeoxycholic acid (UDCA) and chenodeoxycholic acid (CDCA) in bile of treated hamsters significantly increased. Both treatments (TUDCA alone or TUDCA + taurine) decreased the percentage of cholic acid without affecting 3-hydroxy-3-methylglutaryl CoA (HMG-CoA) reductase or cholesterol 7 alpha-hydroxylase activities. Sterol and bile acid content of the feces collected during the period of the study did not show any difference. Bile acid glycine to taurine conjugation ratio (G/T ratio) in TUDCA treated animals was significantly higher in respect to controls after only one week of treatment. On the contrary, bile acid G/T ratio significantly decreased in the group of animals supplemented with taurine, but only after two weeks of treatment.

Topics: Animals; Bile Acids and Salts; Chenodeoxycholic Acid; Cholesterol; Cholesterol 7-alpha-Hydroxylase; Cricetinae; Diet; Feces; Female; Hydroxymethylglutaryl CoA Reductases; Liver; Mesocricetus; Phospholipids; Taurine; Taurochenodeoxycholic Acid

Topics: Adult; Chenodeoxycholic Acid; Cholelithiasis; Female; Humans; Male; Middle Aged; Taurochenodeoxycholic Acid

Studies were carried out using an isolated rat liver system to define: the contribution of exogenous phosphatidylcholine (PC) to biliary phospholipid secretion; and its hepatic metabolism during perfusion of the livers with conjugated bile salts with different hydrophilic/hydrophobic properties. A tracer dose of sn-1-palmitoyl-sn-2-[14C]linoleoylPC was injected as a bolus into the recirculating liver perfusate, under constant infusion of 0.75 mumol/min of tauroursodeoxycholate or taurodeoxycholate. The effects on bile flow, biliary lipid secretion, 14C disappearance from the perfusate and its appearance in bile, as well as hepatic and biliary biotransformation were determined. With both the bile salts, about 40% of the [14C]PC was taken up by the liver from the perfusate over 100 min. During the same period less than 2% of the given radioactivity was secreted into bile. More than 95% of the 14C recovered in bile was located within the identical injected PC molecular species. The biliary secretion of labeled as well as unlabeled PC, however, was significantly higher in livers perfused with taurodeoxycholate than tauroursodeoxycholate, while the reverse was observed with respect to bile flow and total bile salt secretion. The exogenous PC underwent extensive hepatic metabolization which appeared to be influenced by the type of bile salt perfusing the liver. After 2 h perfusion, the liver radioactivity was found, in decreasing order, in PC, triacylglycerol, phosphatidylethanolamine and diacylglycerol. In addition, the specific activity of triacylglycerol was significantly higher in tauroursodeoxycholate than in taurodeoxycholate-perfused livers (P less than 0.025), while the reverse was true for the specific activity of hepatic PC (P less than 0.01). Because taurodeoxycholate and tauroursodeoxycholate showed opposite effects on both biliary lipid secretion and hepatic PC biotransformations, we conclude that the hepatic metabolism of glycerolipids is influenced by the physiochemical properties of bile salts.

Topics: Animals; Bile; Carbon Radioisotopes; Chenodeoxycholic Acid; Deoxycholic Acid; In Vitro Techniques; Liver; Male; Perfusion; Phosphatidylcholines; Rats; Rats, Inbred Strains; Taurochenodeoxycholic Acid; Taurodeoxycholic Acid; Triglycerides

The effect of tauroursodeoxycholate (TU) infusion on the plasma level and biliary transport maximum (Tm) of sulfobromophthalein (BSP) was examined in male rats during a continuous intravenous infusion of BSP with different TU infusion rates. The infusion rate of 0.6 mumol/min/100 gm body weight of TU caused significantly higher bile flow and BSP Tm values compared with the respective control values in rats with only a BSP infusion. These values, however, were significantly lower than values obtained by an equimolar infusion of taurocholate (TC). The higher infusion rates of TU (1.2 and 1.8 mumol/min/100 gm) tended to cause higher bile flow rates, but the BSP Tm value did not increase beyond the value obtained at the lower infusion rate (0.6 mumol/min/100 gm). In the highest TU infusion rate study (1.8 mumol/min/100 gm), plasma BSP concentrations were significantly higher than corresponding control values or values at a lower TU or TC infusion rate. It was concluded that in rats TU can significantly increase the BSP Tm, but to a lesser extent than TC. Furthermore, it was suggested that TU infusion at a higher rate significantly interferes with the hepatic uptake (or storage) of BSP.

Topics: Animals; Bile; Bile Acids and Salts; Biological Transport; Chenodeoxycholic Acid; Male; Rats; Rats, Inbred Strains; Sulfobromophthalein; Taurochenodeoxycholic Acid; Time Factors

It was recently suggested that the apparent biliary transport maximum (Tm, secretory maximum) for bile salts is primarily determined by their degree of cytotoxicity (the cytotoxicity hypothesis), based on experiments on male rats [Hardison, W. G., D. E. Hatoff, K. Miyai, and R. G. Weiner. Am. J. Physiol. 241 (Gastrointest. Liver Physiol. 4): G337-G343, 1981]. To confirm this hypothesis, we determined the Tm of three different bile salts, taurocholate (TC), taurochenodeoxycholate (TCDC), and tauroursodeoxycholate (TUDC) in female rats and hamsters. The order of Tm values in female rats was the same as that reported for male rats (TUDC greater than TC greater than TCDC), whereas in female hamsters it was TC greater than TCDC greater than TUDC. On the other hand, in hamsters, the order of cytotoxicity, evaluated in vivo by the biliary excretion of hepatocyte enzymes such as lactate dehydrogenase and alkaline-phosphatase and an increase in plasma lactate dehydrogenase, aspartate aminotransferase and alanine aminotransferase levels under a fixed rate infusion (0.6 and 1.2 mumol X min-1 X 100 g body wt-1) of bile salts, was inverse to the order of Tm values (TCDC greater than TC greater than TUDC) in rats, but in hamsters, too, TCDC was most cytotoxic. The order of Tm value in hamsters thus does not correspond to the order of cytotoxicity of these bile salts, suggesting that the cytotoxicity of bile salts may not be the sole determinant of bile salt Tm.

Topics: Animals; Biological Transport; Chenodeoxycholic Acid; Cricetinae; Female; Gallbladder; Kinetics; Mesocricetus; Rats; Rats, Inbred Strains; Species Specificity; Taurochenodeoxycholic Acid; Taurocholic Acid

Biliary excretion of various proteins (5'-nucleotidase, alkaline phosphatase, lactate dehydrogenase, and albumin) was investigated in pentobarbital sodium-anesthetized rats infused with different bile salts [taurocholate (TC), taurochenodeoxycholate (TCDC), and tauroursodeoxycholate (TUDC)]. A TCDC infusion at 0.4 mumol . min-1 . 100 g body wt-1 caused much higher increases in the biliary excretion of these proteins compared with the respective values in rats that received an infusion of TC at a threefold higher rate (1.2 mumol . min-1 . 100 g body wt-1). In contrast, a TUDC infusion at 1.8 mumol . min-1 . 100 g body wt-1 showed the minimum effect on these protein leakages. A combined infusion of TCDC (0.4 mumol . min-1 . 100 g-1) and TUDC (0.6 mumol . min-1 . 100 g-1) resulted in drastic (8- to 20-fold) decreases in excretion of these enzymes and albumin compared with respective values in rats infused with TCDC alone. Similar preventive effects were observed with the addition of TUDC to the infusion of TC (1.2 mumol . min-1 . 100 g-1). These results suggest that the hepatic cytotoxic effects of TC and TCDC can be prevented by the simultaneous infusion of TUDC in rats.

Topics: 5'-Nucleotidase; Albumins; Alkaline Phosphatase; Animals; Bile; Bile Acids and Salts; Chenodeoxycholic Acid; Cholestasis; Isomerism; L-Lactate Dehydrogenase; Male; Nucleotidases; Rats; Rats, Inbred Strains; Taurochenodeoxycholic Acid; Taurocholic Acid; Time Factors

Biliary bicarbonate secretion may occur by transport of bicarbonate itself or of H+ (or OH-). To distinguish between these two mechanisms, we have studied the effects of bicarbonate deprivation or substitution by weak acids in the perfusate of isolated rat livers on ursodeoxycholate-induced bicarbonate secretion. Livers were perfused with an erythrocyte-free solution containing either the impermeant buffer Tricine (25 mM) or 25 mM Tricine and 13 mM bicarbonate, acetate, or 5,5-dimethyloxazolidine-2,4-dione (DMO), and ursodeoxycholate was infused. Tauroursodeoxycholate, which does not stimulate bicarbonate secretion, served as a control. During ursodeoxycholate infusion 1) the increase in bile flow, in microliter X min-1 X g liver-1 (+/- SE), was significantly higher in livers perfused with Tricine and bicarbonate (1.29 +/- 0.06), Tricine and acetate (1.46 +/- 0.07), and Tricine and DMO (1.30 +/- 0.04) than in livers perfused with Tricine alone (0.99 +/- 0.04); and 2) biliary bicarbonate, acetate, or DMO concentrations and bile pH were significantly higher than the corresponding perfusate values. In contrast, during tauroursodeoxycholate infusion bile flow was the same whatever the perfusate, and bile pH was lower than pH of the perfusate. Therefore, ursodeoxycholate-induced choleresis and bile alkalinization do not depend on bicarbonate as such (which can be replaced by acetate or DMO). This suggests that ursodeoxycholate-induced biliary bicarbonate secretion is the result of H+ (or OH-) transport rather than transport of bicarbonate itself.

Topics: Animals; Bicarbonates; Bile; Bile Acids and Salts; Deoxycholic Acid; Glycine; Hydrogen-Ion Concentration; Isomerism; Male; Osmolar Concentration; Perfusion; Rats; Rats, Inbred Strains; Taurochenodeoxycholic Acid; Ursodeoxycholic Acid

The bile salts of ursodeoxycholic acid, glycoursodeoxycholic acid, tauroursodeoxycholic acid, chenodeoxycholic acid, glycochenodeoxycholic acid, and taurochenodeoxycholic acid were each found to inhibit pepsin proteolytic activity in vitro at various concentrations against the refined substrate n-APDT. The sodium salt of ursodeoxycholic acid was the most potent pepsin inhibitor among those tested.

Topics: Animals; Chenodeoxycholic Acid; Deoxycholic Acid; Dipeptides; Glycochenodeoxycholic Acid; In Vitro Techniques; Pepsin A; Substrate Specificity; Swine; Taurochenodeoxycholic Acid; Ursodeoxycholic Acid

We examined the intestinal absorption of ursodeoxycholic acid (UDC), glycoursodeoxycholic acid (GUDC) and tauroursodeoxycholic acid (TUDC) using an everted gut sac technique. UDC was absorbed throughout rat small intestine almost to the same extent. Absorption of both GUDC and TUDC, however, varied between jejunum and ileum. Absorption of these conjugated bile acids in the jejunal segments was less than that of UDC. While, absorption of GUDC and TUDC in the terminal ileum was more efficient than UDC. Although 2,4-dinitrophenol had no effect on the jejunal uptake, ileal uptake of these three bile acids was inhibited by 2,4-dinitrophenol.

Topics: Animals; Biological Transport, Active; Chenodeoxycholic Acid; Deoxycholic Acid; In Vitro Techniques; Intestinal Absorption; Kinetics; Male; Rats; Rats, Inbred Strains; Taurochenodeoxycholic Acid; Ursodeoxycholic Acid

Chenodeoxycholic acid (cheno) and ursodeoxycholic acid (urso) dissolve cholesterol gallstones in man. Comparative studies of the absorption of cheno and urso are not available. The absorption of urso and cheno and their glycine and taurine conjugates in jejunum, terminal ileum, and colon of the rat were therefore determined in an open in situ perfusion system. Absorption of unconjugated urso and cheno in jejunum, ileum, and colon was similar. In the jejunum conjugated urso and cheno were absorbed only in minimal amounts. In the ileum glycine-conjugated urso was absorbed to a lower extent than glycine-conjugated cheno (6.5 +/- 0.4 vs. 8.6 +/- 0.6 nmol/cm X h at 25 mumol/l bile acid concentration, p less than 0.05) and taurine-conjugated urso was absorbed less than taurine-conjugated cheno (6.4 +/- 0.5 vs. 8.1 +/- 0.7 nmol/cm X h, p less than 0.05). In the colon glycourso and taurourso were not absorbed, while glycocheno and taurocheno were absorbed in small amounts. The low reabsorption rates of urso conjugates in ileum and colon may contribute to the relatively low urso content in bile during urso treatment.

Topics: Animals; Chenodeoxycholic Acid; Colon; Deoxycholic Acid; Glycochenodeoxycholic Acid; Ileum; Intestinal Absorption; Jejunum; Male; Perfusion; Rats; Rats, Inbred Strains; Taurochenodeoxycholic Acid; Ursodeoxycholic Acid

Six male subjects with normal gastroenterologic function were studied to determine the effects of ursodeoxycholic (15 mg/kg X day) and tauroursodeoxycholic (20 mg/kg X day) acid feeding on bile acid synthesis and cholesterol absorption. Each bile acid was fed for 1 mo and withheld for the next month. Subjects remained on a metabolic ward and consumed a constant diet of 500 mg of cholesterol mixed with solid and liquid formulas. Before the study started, each subject received 50 muCi of [4-14C]cholesterol intravenously. During the study, stools were collected for the determination of 24-h fecal acidic and neutral sterol excretion, and blood was drawn twice weekly for determination of serum cholesterol specific activity. At the end of each month an intestinal perfusion study was performed to measure total bile acid pool size and hourly biliary secretion rates of cholesterol, phospholipid, and bile acid. From these data, the percentage of cholesterol absorption and total endogenous bile acid synthesis could be calculated. Neither ursodeoxycholic nor tauroursodeoxycholic acid feeding decreased endogenous bile acid synthesis. During bile acid feeding periods, the percentage of cholesterol absorption was decreased.

Topics: Bile Acids and Salts; Cholesterol; Deoxycholic Acid; Feces; Humans; Male; Middle Aged; Sterols; Taurochenodeoxycholic Acid; Ursodeoxycholic Acid

The importance of the bile acid structure on mucosal uptake and lymphatic absorption of cholesterol was investigated using four different taurine-conjugated bile acids. Pure synthetic conjugates of a trihydroxy bile acid, taurocholate, and three dihydroxy bile acids, tauroursodeoxycholate, taurochenodeoxycholate, and taurodeoxycholate were used to completely solubilize [14C]cholesterol and polar lipids for steady rate intraduodenal infusion for 8 hr in bile fistula rats. Lymph output and esterification of [14C]cholesterol and endogenous cholesterol were measured in hourly samples. A second group of bile fistula rats was given the same bile acids as the first group but without added cholesterol or other lipid, i.e., fasting lymph fistula group. Mucosal uptake of [14C]cholesterol was studied using recovery of [14C]cholesterol from lumen and mucosa after 1-hr infusions in conscious bile fistula rats. Lymph output of [14C]cholesterol was promoted more rapidly with taurocholate than with the dihydroxy conjugates and [14C]cholesterol output differed for the three groups given dihydroxy bile acids. The mass of cholesterol in lymph, measured chemically, varied in parallel with [14C]cholesterol absorption. For fasting lymph, infusion of dihydroxy bile acids failed to produce a significant change in endogenous cholesterol output when compared with rats given saline only. Taurocholate infusion markedly increased endogenous cholesterol in lymph of fasted rats. Under all conditions where cholesterol output was stimulated, the increase could be accounted for mainly as esterified cholesterol. Mucosal uptake of [14C]cholesterol during 1-hr infusions in conscious bile fistula rats was slower with the dihydroxy bile acids than with taurocholate. The results indicate the marked effect of the number and configuration of the hydroxyl groups on the solubilizing bile acid for cholesterol absorption.

Topics: Absorption; Animals; Biological Transport; Cholesterol; Cholesterol Esters; Fasting; Intestinal Mucosa; Intestine, Small; Lymph; Male; Rats; Rats, Inbred Strains; Taurochenodeoxycholic Acid; Taurocholic Acid; Taurodeoxycholic Acid

Isolated perfused rat livers were used to study the effects of taurochenodeoxycholate (TCDC) and tauroursodeoxycholate (TUDC) upon some aspects of biliary composition. After depletion of the endogenous bile salt pool of the liver, introduction of either bile salt brought about increases in bile flow, bile salt output and biliary phospholipid output. Taurochenodeoxycholate needed a lower biliary concentration to produce phospholipid output than did tauroursodeoxycholate. TCDC perfusion caused a substantial output of plasma-membrane enzymes (5'-nucleotidase and alkaline phosphodiesterase) into the bile, whereas TUDC caused little output of either enzyme; this may represent a characteristic difference between the effects of the two bile salts on the hepatobiliary system. The results from TUDC perfusion indicate also that much of the output of biliary phospholipid promoted by bile salts, may be independent of the output of plasma-membrane enzymes promoted by bile salts.

Topics: 5'-Nucleotidase; Animals; Bile; Bile Acids and Salts; Cell Membrane; Chenodeoxycholic Acid; In Vitro Techniques; Liver; Male; Nucleotidases; Perfusion; Phosphodiesterase I; Phospholipids; Phosphoric Diester Hydrolases; Rats; Rats, Inbred Strains; Taurochenodeoxycholic Acid

A combined infusion of taurocholate (TC) and glycoursodeoxycholate (GU) resulted in a longer choleretic period and a significantly higher excretion of TC compared with the infusion of TC alone, as has been previously observed for the combined infusion of tauroursodeoxycholate (TU) and TC in the rat. It was concluded that GU is as effective as TU in preventing TC induced cholestasis in this species.

Topics: Animals; Bile; Bile Acids and Salts; Chenodeoxycholic Acid; Cholestasis; Deoxycholic Acid; Drug Evaluation, Preclinical; Rats; Secretory Rate; Taurochenodeoxycholic Acid; Taurocholic Acid; Ursodeoxycholic Acid

Bile acids are capable of disrupting the gastric and esophageal mucosal barriers and are known to differ in their ability to injure these mucosae. Two bile acids, chenodeoxycholic and its 7-B epimer, ursodeoxycholic, that are being used to dissolve gallbladder stones were evaluated for their damaging effects on experimental preparations of the esophageal (rabbit) and gastric (dog) mucosa. Damage was assessed by measuring indices of mucosal barrier function, including net acid flux, potential difference, and tissue resistance, before and after exposure to the taurine conjugates of these bile acids. In both the esophageal and gastric mucosa, tauroursodeoxycholic acid caused significantly less disruption of barrier function than taurochenodeoxycholic acid. These results demonstrate that minor differences in conjugated bile acid structure can cause major changes in the effects of bile acids on the upper gastrointestinal mucosa and that ursodeoxycholic acid may be the preferred bile acid for oral ingestion to dissolve gallbladder stones.

Topics: Animals; Bile Acids and Salts; Chenodeoxycholic Acid; Cholelithiasis; Dogs; Esophagus; Gastric Mucosa; Mucous Membrane; Rabbits; Taurochenodeoxycholic Acid

In rats the simultaneous infusion of tauroursodeoxycholate and taurocholate resulted in a longer choleretic condition with higher total bile salt and taurocholate excretion rates as compared to taurocholate infusion alone. A similar but weaker response was observed when taurodehydrocholate was simultaneously infused instead of tauroursodeoxycholate. The taurolithocholate induced cholestasis was most markedly prevented when taurocholate, rather than tauroursodeoxycholate, was simultaneously infused. It was suggested that the effect of tauroursodeoxycholate on the biliary excretion of taurocholate appears to differ from that of taurocholate on taurolithocholate excretion.

Topics: Animals; Bile; Bile Acids and Salts; Male; Rats; Rats, Inbred Strains; Taurochenodeoxycholic Acid; Taurocholic Acid; Taurolithocholic Acid; Time Factors

The nature of transport pathway(s) for the biliary excretion of taurocholate and tauroursodeoxycholate was examined by comparing the biliary transport maximum (Tm) value for taurocholate during the infusion of taurocholate alone with that of taurocholate combined with tauroursodeoxycholate. The combined infusion of tauroursodeoxycholate resulted in an appreciable excretion of tauroursodeoxycholate while the excretion rate of taurocholate was not reduced in comparison with the Tm value of taurocholate alone. Furthermore, the Tm state of taurocholate was maintained for a much longer period with the simultaneous infusion of tauroursodeoxycholate than by the infusion of taurocholate alone. The cholestasis usually produced by the excess infusion of taurocholate was also prevented when tauroursodeoxycholate was simultaneously infused. Since plasma taurocholate concentration was not significantly different from the two rat groups, the results suggest the presence of the facilitative interaction of tauroursodeoxycholate with the taurocholate excretion.

Topics: Animals; Bile Acids and Salts; Chenodeoxycholic Acid; Cholestasis; Kinetics; Male; Rats; Rats, Inbred WF; Taurochenodeoxycholic Acid; Taurocholic Acid

The solubilizing powers of taurocholate, taurochenodeoxycholate and tauroursodeoxycholate for monoolein and cholesterol, and the size of the bile salt-monoolein-cholesterol micelles have been determined. For the three bile salt species, the micellar size depends on the saturation with monoolein. As a result, for a given bile salt to monoolein ratio, the taurochenodeoxycholate micelles are smaller than those of taurocholate and both are smaller than those of tauroursodeoxycholate. Intestinal cholesterol uptake has been studied in vitro as a function of the micellar size and the saturation degree with cholesterol. For a given bile salt to monoolein ration and 1) for low cholesterol concentrations, taurocholate leads to the greatest rates of uptake ; 2) for high cholesterol content, taurochenodeoxycholate induces the largest uptake. The specific micellar characteristics of the tauroursodeoxycholate micelles clearly demonstrate why this bile salt is of so little help in the intestinal uptake of cholesterol.

Topics: Animals; Bile Acids and Salts; Cholesterol; Dose-Response Relationship, Drug; Glycerides; Intestinal Absorption; Intestine, Small; Male; Micelles; Rats; Rats, Inbred Strains; Solubility; Taurochenodeoxycholic Acid; Taurocholic Acid

Topics: Chenodeoxycholic Acid; Colon; Diarrhea; Feces; Humans; Ileum; Intestinal Mucosa; Taurochenodeoxycholic Acid

It has been reported that biliary secretion is the limiting step in the hepatic transport of bile acids by the hepatocyte from plasma to canalicular bile. The aim of the present study was to examine the role of conjugation in the transport process using ursodeoxycholate (UDCA) and tauroursodeoxycholate (TUDCA), two bile acid with low liver toxicity. Rats were given constant intravenous infusions of cholate (C), taurocholate (TC), UDCA, or TUDCA at progressively increasing rates. The biliary maximum secretory rate (SRm), in nmol . min-1 . 100 g body wt-1, for TC (1,835.2 +/- 135.5, mean +/- SE) was not significantly different from that of C (1,749.4 +/- 85.6). In contrast, the SRm for TUDCA (5,909.4 +/- 304.4) was approximately sevenfold that of UDCA (802.1 +/- 134.2), the difference being statistically significant (P less than 0.001). The SRm of UDCA in the presence of a taurine infusion (1,367 +/- 84.4) was higher than that of UDCA infused alone but still much lower than that of TUDCA. Phenobarbital sodium pretreatment did not increase SRm of UDCA alone or in the presence of a taurine infusion. These results suggest that in the rat 1) conjugation is the rate-limiting step in the overall transport of UDCA (and perhaps other bile acids) by the liver, and 2) the conjugation process itself is limiting, rather than the availability of taurine. They support the view that, although not mandatory for secretion into bile, conjugation of bile acids confers a biological advantage, possibly by increasing the solubility of the bile acid.

Topics: Animals; Bile Acids and Salts; Biological Transport; Cholic Acids; Chromatography, Thin Layer; Deoxycholic Acid; Liver; Male; Rats; Rats, Inbred Strains; Taurine; Taurochenodeoxycholic Acid; Taurocholic Acid; Ursodeoxycholic Acid

Cholesterol uptake by everted rat jejunal sacs is lower from mixed micelles containing tauroursodeoxycholate than from those with taurocholate or taurochenodeoxycholate. This occurs in spite of a greater saturation with cholesterol of tauroursodeoxycholate micelles as measured by equilibrium solubility studies. The results suggest that cholesterol saturation of solutions containing tauroursodeoxycholate is overestimated when calculated with reference to solubility in micellar form.

Topics: Animals; Chenodeoxycholic Acid; Cholesterol; In Vitro Techniques; Jejunum; Male; Micelles; Rats; Solubility; Taurochenodeoxycholic Acid; Taurocholic Acid

Separation of the glycine and taurine conjugates of ursodeoxycholic acid from those of lithocholic acid, chenodeoxycholic acid, deoxycholic acid, and cholic acid by thin-layer chromatography is described. Thus, on running a silica gel G plate first in a solvent system of n-butanol-water 20:3 and then in a second solvent system of chloroform-isopropanol-acetic acid-water 30:20:4:1, all the above-mentioned conjugated bile acids are separated from one another. The application of this method to study the change in the biliary bile acid conjugation pattern in ursodeoxycholic acid-fed gallstone patients is described.

Topics: Chenodeoxycholic Acid; Chromatography, Thin Layer; Deoxycholic Acid; Glycine; Glycochenodeoxycholic Acid; Glycocholic Acid; Glycodeoxycholic Acid; Lithocholic Acid; Taurochenodeoxycholic Acid; Taurocholic Acid; Taurodeoxycholic Acid; Taurolithocholic Acid; Ursodeoxycholic Acid

Topics: Animals; Bile; Chenodeoxycholic Acid; Cholagogues and Choleretics; Kinetics; Male; Rats; Rats, Inbred Strains; Taurochenodeoxycholic Acid; Taurocholic Acid