ex-527 and Disease-Models--Animal

Progesterone resistance, a known pathologic condition associated with a reduced cellular response to progesterone and heightened estrogen responses, appears to have a normal physiologic role in mammalian reproduction. The molecular mechanism responsible for progesterone resistance in normal and abnormal endometrium remains unclear.. To examine the roles of sirtuin-1 (SIRT1) in normal endometrium as well as endometrium associated with infertility and endometriosis, as an epigenetic modulator associated with progesterone resistance.. SIRT1 expression was examined by Western blot, quantitative real-time polymerase chain reaction, and immunohistochemistry in mouse uterus and human endometrium. Mice with uterine specific Sirt1 overexpression were developed to examine SIRT1's role in endometrial function and endometriosis development. EX-527, a SIRT1 inhibitor, and SRT1720, a SIRT1 agonist, were also used to evaluate SIRT1 effect on endometriosis.. In normal healthy women, endometrial SIRT1 is expressed only during menses. SIRT1 was dramatically overexpressed in the endometrium from women with endometriosis in both the epithelium and stroma. In mice, SIRT1 is expressed at the time of implantation between day 4.5 and 5.5 of pregnancy. Overexpression of SIRT1 in the mouse uterus leads to subfertility due to implantation failure, decidualization defects and progesterone resistance. SIRT1 overexpression in endometriotic lesions promotes worsening endometriosis development. EX-527 significantly reduced the number of endometriotic lesions in the mouse endometriosis model.. SIRT1 expression and progesterone resistance appears to play roles in normal endometrial functions. Aberrant SIRT1 expression contributes to progesterone resistance and may participate in the pathophysiology of endometriosis. SIRT1 is a novel and targetable protein for the diagnosis as well as treatment of endometriosis and the associated infertility seen in this disease.

Topics: Adult; Animals; Carbazoles; Case-Control Studies; Disease Models, Animal; Embryo Implantation; Endometriosis; Endometrium; Epigenesis, Genetic; Female; Heterocyclic Compounds, 4 or More Rings; Humans; Infertility, Female; Menstruation; Mice; Mice, Transgenic; Middle Aged; Progesterone; Sirtuin 1; Uterine Diseases; Young Adult

Inflammation plays a major role in the pathogenesis of acute lung injury (ALI), but the mechanism remains unclear. Current anti-inflammatory therapy has poor efficacy on ALI. The aim of this study was to investigate the protective mechanism of curcumin against ALI. In in vivo experiments, curcumin significantly alleviated lung inflammation, histopathological injury and MPO activity, serum concentrations of CCL7, IL-6 and TNF-α, and mortality in mice compared to the model group. RAW264.7 cells cultured in the presence of lipopolysaccharide and adenosine triphosphate showed significantly lower viability, higher pyroptotic percentage and inflammation, but supplement of curcumin increased the cell viability, reduced pyroptosis and inflammation. Additionally, the expressions of NF-κB and pyroptosis related proteins were notably increased, while Sirtuin 1 (SIRT1) was decreased in both in vivo and in vitro ALI models. The results suggested that curcumin remarkably inhibited the expression of NF-κB and pyroptosis related proteins and increased the expression of SIRT1. However, EX527, a SIRT1 inhibitor, blocked the protective effect of curcumin against ALI. In conclusion, curcumin has protective effect against ALI. It may inhibit inflammatory process by inhibiting the activation of NLRP3 inflammasome-dependent pyroptosis through the up-regulation of SIRT1.

Topics: Acute Lung Injury; Adenosine Triphosphate; Animals; Anti-Inflammatory Agents; Carbazoles; Curcumin; Disease Models, Animal; Inflammasomes; Inflammation; Lipopolysaccharides; Male; Mice; Mice, Inbred C57BL; NF-kappa B; NLR Family, Pyrin Domain-Containing 3 Protein; Pyroptosis; RAW 264.7 Cells; Sirtuin 1

The anti-inflammatory effect of glycyrrhizin has been widely recognized, while the specific mechanism of glycyrrhizin in psoriasis remains poorly understood.. In the imiquimod-induced mouse model of psoriasis (IMD), we found that glycyrrhizin can substantially improve the adverse symptoms in mice. The hematoxylin-eosin staining results showed that glycyrrhizin can also improve the pathological state of skin cells in IMD mice. Using enzyme-linked immunosorbent assay (ELISA), we found that glycyrrhizin substantially inhibited the expression of IL-17A and IFN-γ in the serum of IMD mice. In order to simulate the effect of IL-17A on keratinocytes in psoriasis, we treated HaCaT cells with 100 ng/mL IL-17A (IL-17A-HaCaT cells) for 48 h. Then, using cell-counting kit-8 (CCK-8) and ELISA assays, we found that glycyrrhizin inhibited the proliferation of IL-17A-HaCaT cells and reversed the promotion of IL-6, CCL20, and TNF-α induced by IL-17A. Further, western blotting (WB) results indicated that glycyrrhizin promoted the expression of SIRT1 and inhibited the expression of STAT3 and phosphorylated STAT3 (p-STAT3). By treating IL-17A-HaCaT cells with EX-527 (a potent and selective inhibitor of SIRT1), combined with CCK-8 and WB experiments, we initially found that EX-527 inhibited the proliferation of IL-17A-HaCaT cells and promoted the expression of STAT3, p-STAT3, and acetylated STAT3 (a-STAT3). However, when glycyrrhizin was added at the same time, the proliferation of IL-17A-HaCaT cells increased, and the expression of STAT3, p-STAT3, and a-STAT3 reduced. We then knocked down the expression of SIRT1 via small interfering RNA in IL-17A-HaCaT cells, and the results were consistent with those of EX-527.. Together, these results indicated that glycyrrhizin improved psoriasis by inhibiting the expression of IL-17A and IFN-γ in vivo and suppressed the proliferation of IL-17A-HaCaT cells and the expression of STAT3, p-STAT3, and a-STAT3 by upregulating SIRT1 in vitro.

Topics: Adult; Animals; Anti-Inflammatory Agents; Carbazoles; Disease Models, Animal; Female; Glycyrrhiza; Glycyrrhizic Acid; HaCaT Cells; Humans; Imiquimod; Interleukin-17; Mice; Psoriasis; RNA, Small Interfering; Sirtuin 1; Skin; STAT3 Transcription Factor

Machado-Joseph disease (MJD, also known as spinocerebellar ataxia type 3) is a fatal neurodegenerative disease that impairs control and coordination of movement. Here we tested whether treatment with the histone deacetylase inhibitor sodium valproate (valproate) prevented a movement phenotype that develops in larvae of a transgenic zebrafish model of the disease. We found that treatment with valproate improved the swimming of the MJD zebrafish, affected levels of acetylated histones 3 and 4, but also increased expression of polyglutamine expanded human ataxin-3. Proteomic analysis of protein lysates generated from the treated and untreated MJD zebrafish also predicted that valproate treatment had activated the sirtuin longevity signaling pathway and this was confirmed by findings of increased SIRT1 protein levels and sirtuin activity in valproate treated MJD zebrafish and HEK293 cells expressing ataxin-3 84Q, respectively. Treatment with resveratrol (another compound known to activate the sirtuin pathway), also improved swimming in the MJD zebrafish. Co-treatment with valproate alongside EX527, a SIRT1 activity inhibitor, prevented induction of autophagy by valproate and the beneficial effects of valproate on the movement in the MJD zebrafish, supporting that they were both dependent on sirtuin activity. These findings provide the first evidence of sodium valproate inducing activation of the sirtuin pathway. Further, they indicate that drugs that target the sirtuin pathway, including sodium valproate and resveratrol, warrant further investigation for the treatment of MJD and related neurodegenerative diseases.

Topics: Acetylation; Animals; Animals, Genetically Modified; Ataxin-3; Autophagy; Carbazoles; Disease Models, Animal; Drug Evaluation, Preclinical; Drug Synergism; Genes, Reporter; HEK293 Cells; Histone Deacetylase Inhibitors; Histones; Humans; Machado-Joseph Disease; Peptides; Protein Processing, Post-Translational; Recombinant Fusion Proteins; Repressor Proteins; Resveratrol; Signal Transduction; Sirtuin 1; Sirtuins; Swimming; Trinucleotide Repeat Expansion; Valproic Acid; Zebrafish; Zebrafish Proteins

When Zika virus emerged as a public health emergency there were no drugs or vaccines approved for its prevention or treatment. We used a high-throughput screen for Zika virus protease inhibitors to identify several inhibitors of Zika virus infection. We expressed the NS2B-NS3 Zika virus protease and conducted a biochemical screen for small-molecule inhibitors. A quantitative structure-activity relationship model was employed to virtually screen ∼138,000 compounds, which increased the identification of active compounds, while decreasing screening time and resources. Candidate inhibitors were validated in several viral infection assays. Small molecules with favorable clinical profiles, especially the five-lipoxygenase-activating protein inhibitor, MK-591, inhibited the Zika virus protease and infection in neural stem cells. Members of the tetracycline family of antibiotics were more potent inhibitors of Zika virus infection than the protease, suggesting they may have multiple mechanisms of action. The most potent tetracycline, methacycline, reduced the amount of Zika virus present in the brain and the severity of Zika virus-induced motor deficits in an immunocompetent mouse model. As Food and Drug Administration-approved drugs, the tetracyclines could be quickly translated to the clinic. The compounds identified through our screening paradigm have the potential to be used as prophylactics for patients traveling to endemic regions or for the treatment of the neurological complications of Zika virus infection.

Topics: Animals; Antiviral Agents; Artificial Intelligence; Chlorocebus aethiops; Disease Models, Animal; Drug Evaluation, Preclinical; High-Throughput Screening Assays; Immunocompetence; Inhibitory Concentration 50; Methacycline; Mice, Inbred C57BL; Protease Inhibitors; Quantitative Structure-Activity Relationship; Small Molecule Libraries; Vero Cells; Zika Virus; Zika Virus Infection

Food consumption is fundamental for life, and eating disorders often result in devastating or life-threatening conditions. Anorexia nervosa (AN) is characterized by a persistent restriction of energy intake, leading to lowered body weight, constant fear of gaining weight, and psychological disturbances of body perception. Herein, we demonstrate that SIRT1 inhibition, both genetically and pharmacologically, delays the onset and progression of AN behaviors in activity-based anorexia (ABA) models, while SIRT1 activation accelerates ABA phenotypes. Mechanistically, we suggest that SIRT1 promotes progression of ABA, in part through its interaction with NRF1, leading to suppression of a NMDA receptor subunit Grin2A. Our results suggest that AN may arise from pathological positive feedback loops: voluntary food restriction activates SIRT1, promoting anxiety, hyperactivity, and addiction to starvation, exacerbating the dieting and exercising, thus further activating SIRT1. We propose SIRT1 inhibition can break this cycle and provide a potential therapy for individuals suffering from AN.

Topics: Animals; Anorexia Nervosa; Body Weight; Carbazoles; Disease Models, Animal; Female; Gene Expression Regulation; Heterocyclic Compounds, 4 or More Rings; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Nerve Tissue Proteins; Nuclear Respiratory Factor 1; Phenotype; Receptors, N-Methyl-D-Aspartate; Resveratrol; Sirtuin 1; Stress, Mechanical; Up-Regulation

Sirtuin 1 (SIRT1) is involved in the pathogenesis of allergic asthma. This study aimed to investigate whether EX‑527, a specific SIRT1 inhibitor, exerted suppressive effects on allergic airway inflammation in mice submitted to ovalbumin (OVA) inhalation. In addition, this study assessed whether such a protective role was mediated by autophagy suppression though mammalian target of rapamycin (mTOR) activation. Female C57BL/6 mice were sensitized to OVA and EX‑527 (10 mg/kg) was administered prior to OVA challenge. The study found that EX‑527 reversed OVA‑induced airway inflammation, and reduced OVA‑induced increases in inflammatory cytokine expression, and total cell and eosinophil counts in bronchoalveolar lavage fluid. In addition, EX‑527 enhanced mTOR activation, thereby suppressing autophagy in allergic mice. To assess whether EX‑527 inhibited airway inflammation in asthma through the mTOR‑mediated autophagy pathway, rapamycin was administered to mice treated with EX‑527 after OVA sensitization. All effects induced by EX‑527, including increased phosphorylated‑mTOR and decreased autophagy, were abrogated by rapamycin treatment. Taken together, the present findings indicated that EX‑527 may inhibit allergic airway inflammation by suppressing autophagy, an effect mediated by mTOR activation in allergic mice.

Topics: Administration, Inhalation; Animals; Asthma; Autophagy; Carbazoles; Cytokines; Disease Models, Animal; Down-Regulation; Female; Mice; Mice, Inbred C57BL; Ovalbumin; Phosphorylation; Sirolimus; Sirtuin 1; TOR Serine-Threonine Kinases

Sirtuin 2 (SIRT2) is a protein lysine deacylase that has been indicated as a therapeutic target for cancer. To further establish the role of SIRT2 in cancers, it is necessary to develop selective and potent inhibitors. Here, we report the facile synthesis of novel lysine-derived thioureas as mechanism-based SIRT2 inhibitors with anticancer activity. Compounds AF8, AF10, and AF12 selectively inhibited SIRT2 with IC

Topics: Animals; Antineoplastic Agents; Binding Sites; Cell Line, Tumor; Cell Proliferation; Colorectal Neoplasms; Disease Models, Animal; Drug Design; Drug Screening Assays, Antitumor; Female; Humans; Lysine; Male; Mice; Mice, Transgenic; Molecular Docking Simulation; Protein Isoforms; Sirtuin 2; Structure-Activity Relationship; Thiourea

High mobility group box-1 (HMGB1), recognized as a representative of damage-associated molecular patterns, is released during cell injury/death, triggering the inflammatory response and ultimately resulting in tissue damage. Dozens of studies have shown that HMGB1 is involved in certain diseases, but the details on how injured hepatocytes release HMGB1 need to be elicited.. To reveal HMGB1 release mechanism in hepatocytes undergoing oxidative stress.. When hepatocytes were damaged, HMGB1 translocated from the nucleus to the cytoplasm because of its hyperacetylation and was passively released outside both in vivo and in vitro. After treatment with Sirt1-siRNA or Sirt1 inhibitor (EX527), the hyperacetylated HMGB1 in hepatocytes increased, and Sirt1 activity inhibited by H. The functional inhibition between Parp1 and Sirt1 leads to HMGB1 hyperacetylation, which leads to its translocation from the nucleus to the cytoplasm and finally outside the cell.

Topics: Acetylation; Animals; Carbazoles; Cell Line; Cell Nucleus; Cells, Cultured; Cytoplasm; Diet, High-Fat; Disease Models, Animal; Ethanol; Fatty Liver; Hepatocytes; HMGB1 Protein; Humans; Hydrogen Peroxide; Liver; Liver Function Tests; Male; Mice; Oxidative Stress; Poly (ADP-Ribose) Polymerase-1; Quinolinium Compounds; RNA, Small Interfering; Sirtuin 1

Necroptosis, a novel type of programmed cell death, is involved in ischemia-reperfusion-induced brain injury. Sirtuin 1 (Sirt1), as a well-known member of histone deacetylase class III, plays pivotal roles in inflammation, metabolism, and neuron loss in cerebral ischemia. We explored the relationship between Sirt1 and the necroptosis signaling pathway and its downstream events by administration of ex-527, as a selective and potent inhibitor of Sirt1, and necrostatin-1 (nec-1), as a necroptosis inhibitor, in an animal model of focal cerebral ischemia. Our data showed different patterns of sirt1 and necroptosis critical regulators, including receptor-interacting protein kinase 3 and mixed lineage kinase domain-like protein gene expressions in the prefrontal cortex and the hippocampus after ischemia-reperfusion. We found that ex-527 microinjection reduces the infarction volume of ischemic brains and improves the survival rate, but not stroke-associated neurological deficits. Additionally, treatment with ex-527 effectively abolished the elevation of the critical regulators of necroptosis, whereas necroptosis inhibition through nec-1 microinjection did not influence Sirt1 expression levels. Our data also demonstrated that the ex-527 relieves ischemia-induced perturbation of necroptosis-associated metabolic enzymes activity in downstream. This study provides a new approach to the possible neuroprotective potential of ex-527 orchestrated by necroptosis pathway inhibition to alleviate ischemia-reperfusion brain injury.

Topics: Animals; Carbazoles; Cell Death; Disease Models, Animal; Energy Metabolism; Gene Expression Regulation; Hippocampus; Imidazoles; Indoles; Infarction, Middle Cerebral Artery; Male; Neuroprotective Agents; Prefrontal Cortex; Protein Kinases; Rats, Wistar; Receptor-Interacting Protein Serine-Threonine Kinases; Reperfusion Injury; Signal Transduction; Sirtuin 1

Sepsis-induced brain injury is frequently encountered in critically ill patients with severe systemic infection. Butein (3,4,2',4'-tetrahydroxychalcone) has been demonstrated as the neuro-protective agent via reducing inflammation and oxidative stress on neurons. Moreover, activation of silent information regulator 1 (SIRT1) inhibits apoptosis, oxidation and inflammation thus alleviating sepsis-induced multiorgan injuries. In present study, we show that butein administrated intraperitoneally (10 mg/kg) saved mice from sepsis-induced lethality by increasing 7-day survival rate after cecal ligation and puncture (CLP) surgery. Additionally, butein treatment enhanced SIRT1 signaling thus decreasing the Ac-NF-κB, Ac-FOXO1 and Ac-p53 levels, thus attenuating the brain injury of mice after CLP surgery by decreasing cerebral edema, maintaining the blood-brain barrier integrity, inhibiting neuronal apoptosis, and decreasing pro-inflammatory cytokines production (IL-6, TNF-α and IL-1β) and oxidative stress (downregulation of MDA, and upregulation of SOD and CAT) in both serum and cerebral cortex tissues. Moreover, butein treatment attenuated LPS induced neurological function loss. However, all above mentioned neuro-protective actions of butein were partially inhibited by EX527 co-treatment, one standard SIRT1 inhibitor. Collectively, butein attenuates sepsis-induced brain injury through alleviation of cerebral inflammation, oxidative stress and apoptosis by SIRT1 signaling activation.

Topics: Animals; Apoptosis; Blood-Brain Barrier; Carbazoles; Chalcones; Disease Models, Animal; Humans; Inflammation; Male; Mice; Mice, Inbred C57BL; Neuroprotective Agents; Oxidative Stress; Sepsis; Sepsis-Associated Encephalopathy; Signal Transduction; Sirtuin 1; Treatment Outcome

Melatonin is reportedly associated with intervertebral disc degeneration (IDD). Endplate cartilage is vitally important to intervertebral discs in physiological and pathological conditions. However, the effects and mechanism of melatonin on endplate chondrocytes (EPCs) are still unclear. Herein, we studied the effects of melatonin on EPC apoptosis and calcification and elucidated the underlying mechanism. Our study revealed that melatonin treatment decreases the incidence of apoptosis and inhibits EPC calcification in a dose-dependent manner. We also found that melatonin upregulates Sirt1 expression and activity and promotes autophagy in EPCs. Autophagy inhibition by 3-methyladenine reversed the protective effect of melatonin on apoptosis and calcification, while the Sirt1 inhibitor EX-527 suppressed melatonin-induced autophagy and the protective effects of melatonin against apoptosis and calcification, indicating that the beneficial effects of melatonin in EPCs are mediated through the Sirt1-autophagy pathway. Furthermore, melatonin may ameliorate IDD in vivo in rats. Collectively, this study revealed that melatonin reduces EPC apoptosis and calcification and that the underlying mechanism may be related to Sirt1-autophagy pathway regulation, which may help us better understand the association between melatonin and IDD.

Topics: Animals; Apoptosis; Autophagy; Calcinosis; Carbazoles; Cells, Cultured; Chondrocytes; Disease Models, Animal; Female; Intervertebral Disc Degeneration; Male; Melatonin; Oxidative Stress; Protective Agents; Rats, Sprague-Dawley; Sirtuin 1; tert-Butylhydroperoxide

To study the antinociceptive effect of single and repeated doses of resveratrol in a bone cancer pain model, and whether this effect is prevented by the Silent Information Regulator 1 (SIRT1) inhibitor selisistat.. The femoral intercondylar bone of BALB/c mice was injected with 1 000 000 BJ3Z cancer cells. Bone resorption and tumour mass growth (measured by in vivo X-ray and fluorescence imaging), as well as mechanical nociceptive thresholds (von Frey device) and dynamic functionality (rotarod machine), were evaluated during the following 4 weeks. Acute resveratrol (100 mg/kg i.p.) and/or selisistat (10 mg/kg s.c.) were administered on day 14. Chronic resveratrol (100 mg/kg i.p., daily) and/or selisistat (0.5 μg/h s.c., Alzet pump) were administered between days 14 and 20.. Tumour growth gradually incremented until day 31, while mechanical hyperalgesia started on day 3 after cancer cell injection. Acute resveratrol increased the mechanical threshold of pain (peaking at 1.5 h), while the dynamic functionality decreased. Chronic resveratrol produced a sustained antinociceptive effect on mechanical hyperalgesia and improved the loss of dynamic functionality induced by the bone cancer tumour. Selisistat prevented all the effects of resveratrol.. Acute and chronic resveratrol induces antinociceptive effect in the model of metastatic osseous oncological pain, an effect that would be mediated by SIRT1 molecular signalling.

Topics: Analgesics; Animals; Behavior, Animal; Bone Neoplasms; Cancer Pain; Carbazoles; Cell Line, Tumor; Disease Models, Animal; Hyperalgesia; Male; Mice; Mice, Inbred BALB C; Resveratrol; Sirtuin 1

 Inflammation plays an important role in thrombus formation, and Sirtuin 1 (SIRT1) negatively regulates inflammation via deacetylating nuclear factor-kappa B. However, the relationship between SIRT1-regulated inflammation and deep vein thrombosis (DVT) is still unknown..  The aim of this study was to investigate whether SIRT1 plays a critical role in inferior vena cava (IVC) stenosis-induced DVT..  Thrombus weight and histopathologic analysis of IVC were evaluated at different time points after IVC stenosis in rats. Serum levels of inflammatory cytokines and protein expressions of SIRT1, acetylated p65 (Ace-p65), phosphorylated p65 (p-p65) and tissue factor (TF) in thrombosed IVC were assessed. Besides, the effects of resveratrol (RES, a SIRT1 agonist) and EX527 (a selective SIRT1 inhibitor) on DVT were evaluated..  Thrombus weight was increased from 1 to 3 days after IVC stenosis, and then was decreased afterwards. Leukocytes infiltration appeared and serum levels of cytokines were significantly increased in rats of IVC stenosis. SIRT1 protein expression was significantly down-regulated at 1 hour and 1 day after stenosis, while p-p65, Ace-p65 and TF protein expressions appeared a contrary trend. RES reduced thrombus weight, leukocytes infiltration, levels of tumour necrosis factor-α and interleukin-1β and protein expressions of Ace-p65 and TF as well. Moreover, RES significantly increased the protein and messenger ribonucleic acid expressions of SIRT1, while EX527 abolished the protective effects of RES..  SIRT1 activation attenuated IVC stenosis-induced DVT via anti-inflammation in rats. Therefore, SIRT1 may be a potential therapeutic target that could ameliorate DVT.

Topics: Acetylation; Animals; Anti-Inflammatory Agents; Carbazoles; Disease Models, Animal; Female; Fibrinolytic Agents; Histone Deacetylase Inhibitors; Inflammation; Inflammation Mediators; Male; Phosphorylation; Rats, Sprague-Dawley; Resveratrol; Signal Transduction; Sirtuin 1; Time Factors; Transcription Factor RelA; Vena Cava, Inferior; Venous Thrombosis

Chronic unpredictable mild stress (CUMS) is an important risk factor for depression and cognitive deficits in humans. Enriched environment (EE) showed a beneficial effect on depression and cognition by enhancing brain derived neurotrophic factor (BDNF) expression and synaptic plasticity. However, it is still not clearly understood whether an epigenetic mechanism is involved in the BDNF modulation and synaptic plasticity that occurs after EE treatment for the depressive-like behaviors and cognitive deficits elicited by CUMS. In this study, we investigated the possible mechanism of the neuroprotective effect of EE.. All rats were exposed to the 5-week CUMS procedure except the control group. After CUMS procedure, some rats were stereotaxically injected with SIRT1 pharmacologic inhibitor EX527 or SIRT1 knocking down lentivirus (sh-SIRT1) in the hippocampus followed by EE treatment for 3 weeks. Other rats were directly subjected to EE treatment without stereotaxic injection. Behavioral tests were used to appraise depression and cognition after EE treatment. Then epigenetic molecules, synaptic proteins, dendritic spine density and branches, and synaptic morphology of the dorsal hippocampus were determined.. We found that CUMS induced depressive-like behaviors including decreased sucrose preference ratio, prolonged immobility and reduced locomotor and exploratory activity; cognitive deficits including spatial learning and memory impairment; reduced dendritic spine density and number of branches; thinned postsynaptic density; downregulated SIRT1/microRNA-134 pathway, decreased BDNF and synaptic proteins including synaptophysin (SYN) and postsynaptic density protein 95 (PSD95) expression in the hippocampus. However, the CUMS-induced depressive-like behaviors, cognitive deficits, dendritic spine density and branch number reduction, postsynaptic density thinning, SIRT1/microRNA-134 pathway downregulation, BDNF and synaptic proteins reduction, including synaptophysin (SYN) and postsynaptic density protein 95 (PSD95), were reversed by EE treatment. However, depressive-like behaviors and cognitive deficits were observed again in rats subjected to stereotaxic injection with EX527 or sh-SIRT1. Furthermore, this study also found that SIRT1/microRNA-134 regulates the downstream molecules BDNF, and the synaptic proteins SYN and PSD95 in primary cultured hippocampal neurons.. This study provides evidence for the neuroprotective role of EE on depression and cognitive deficits by activating the SIRT1/microRNA-134 pathway, which accounts for the regulation of synaptic proteins, including BDNF, PSD95 and SYN, dendritic remodeling and ultrastructure changes of synapses in the hippocampus.

Topics: Animals; Brain-Derived Neurotrophic Factor; Carbazoles; Chronic Disease; Cognitive Dysfunction; Depression; Disease Models, Animal; Hippocampus; Male; MicroRNAs; Neuronal Plasticity; Rats; Signal Transduction; Sirtuin 1; Socioenvironmental Therapy; Stress, Psychological; Synaptophysin

Sirtuin 1 (Sirt1) exerts its cardioprotective effects in various cardiovascular diseases via multiple cellular activities. However, the therapeutic implications of Sirt1 in hypoxic cardiomyocytes and the underlying mechanisms remain elusive. The present study investigated whether Sirt1 regulates autophagy and apoptosis in hypoxic H9C2 cardiomyocytes and in an experimental hypoxic mouse model. Right ventricular outflow tract biopsies were obtained from patients with cyanotic or acyanotic congenital heart diseases. Adenovirus Ad‑Sirt1 was used to activate Sirt1 and Ad‑Sh‑Sirt1 was used to inhibit Sirt1 expression in H9C2 cells, in order to investigate the effect of Sirt1 on cellular autophagy and apoptosis. SRT1720, a pharmacological activator of Sirt1 and EX‑527, a Sirt1 antagonist, were administered to mice to explore the role of Sirt1 in hypoxic cardiomyocytes in vivo. The levels of autophagy and apoptosis‑related proteins were evaluated using western blotting. Apoptosis was investigated by TUNEL staining and Annexin V/7‑aminoactinomycin D flow cytometry analysis. Heart tissue samples from cyanotic patients exhibited increased autophagy and apoptosis, as well as elevated Sirt1 levels, compared with the noncyanotic control samples. The data from the western blot analysis revealed that Sirt1 promoted autophagic flux and reduced apoptosis in hypoxic H9C2 cells. In addition, Sirt1 activated AMP‑activated protein kinase (AMPK), and the AMPK inhibitor Compound C abolished the effect of Sirt1 on autophagy activation. Further exploration of the mechanism revealed that Sirt1 protects hypoxic cardiomyocytes from apoptosis, at least in part, through inositol requiring kinase enzyme 1α (IRE1α). Consistent with the in vitro results, treatment with the Sirt1 activator SRT1720 activated AMPK, inhibited IRE1α, enhanced autophagy, and decreased apoptosis in the heart tissues of normoxic mice compared with the hypoxia control group. Opposite changes were observed in hypoxic mice treated with the Sirt1 inhibitor EX‑527. These results suggested that Sirt1 promoted autophagy via AMPK activation and reduced hypoxia‑induced apoptosis via the IRE1α pathway, to protect cardiomyocytes from hypoxic stress.

Topics: AMP-Activated Protein Kinases; Animals; Apoptosis; Autophagy; Carbazoles; Cell Hypoxia; Cell Line; Cyanosis; Disease Models, Animal; Endoribonucleases; Female; Heterocyclic Compounds, 4 or More Rings; Humans; Infant; Male; Mice, Inbred C57BL; Myocardium; Myocytes, Cardiac; Protective Agents; Protein Serine-Threonine Kinases; Sirtuin 1; Stress, Physiological; Up-Regulation

MicroRNA-199a (miR-199a) is a novel gene regulator with an important role in inflammation and lung injury. However, its role in the pathogenesis of sepsis-induced acute respiratory distress syndrome (ARDS) is currently unknown. Our study explored the role of miR-199a in sepsis-induced ARDS and its mechanism of action. First, we found that LPS could upregulate miR-199a in alveolar macrophages. Downregulation of miR-199a inhibited the upregulation of inflammatory cytokines in alveolar macrophages and induced the remission of histopathologic changes, the reduction of proinflammatory cytokines, and the upregulation of apoptosis protein expression in an ARDS lung, showing a protective role for miR-199a. We further identified sirtuin 1 (SIRT1) as a direct target of miR-199a in alveolar macrophages, and the expression of SIRT1 was negatively correlated with the level of miR-199a. The protective role of miR-199a downregulation in LPS-stimulated alveolar macrophages and sepsis-induced ARDS could be attenuated by SIRT1 inhibitor. Taken together, these results indicate that downregulation of miR-199a might protect lung tissue against sepsis-induced ARDS by upregulation of SIRT1 through the suppression of excessive inflammatory responses and the inhibition of cellular apoptosis in lung tissue, suggesting its potential therapeutic effects on sepsis-induced ARDS.

Topics: 3' Untranslated Regions; Acute Lung Injury; Animals; Antagomirs; Apoptosis; Binding Sites; Burns; Carbazoles; Cytokines; Disease Models, Animal; Down-Regulation; Gene Expression Regulation, Enzymologic; Histone Deacetylase Inhibitors; Inflammation Mediators; Lung; Macrophages, Alveolar; Male; Mice, Inbred C57BL; MicroRNAs; Pseudomonas aeruginosa; Pseudomonas Infections; Respiratory Distress Syndrome; Sepsis; Signal Transduction; Sirtuin 1

Preservation of bone mass is crucial for healthy ageing and largely depends on adequate responses of matrix-embedded osteocytes. These cells control bone formation and resorption concurrently by secreting the WNT/β-catenin antagonist sclerostin (SOST). Osteocytes reside within a low oxygen microenvironment, but whether and how oxygen sensing regulates their function remains elusive. Here, we show that conditional deletion of the oxygen sensor prolyl hydroxylase (PHD) 2 in osteocytes results in a high bone mass phenotype, which is caused by increased bone formation and decreased resorption. Mechanistically, enhanced HIF-1α signalling increases Sirtuin 1-dependent deacetylation of the Sost promoter, resulting in decreased sclerostin expression and enhanced WNT/β-catenin signalling. Additionally, genetic ablation of PHD2 in osteocytes blunts osteoporotic bone loss induced by oestrogen deficiency or mechanical unloading. Thus, oxygen sensing by PHD2 in osteocytes negatively regulates bone mass through epigenetic regulation of sclerostin and targeting PHD2 elicits an osteo-anabolic response in osteoporotic models.

Topics: Acetylation; Adaptor Proteins, Signal Transducing; Animals; Bone Density; Carbazoles; Cell Line; Coculture Techniques; Disease Models, Animal; Epigenesis, Genetic; Female; Glycoproteins; Heterocyclic Compounds, 4 or More Rings; Humans; Hypoxia-Inducible Factor 1, alpha Subunit; Hypoxia-Inducible Factor-Proline Dioxygenases; Intercellular Signaling Peptides and Proteins; Male; Mice, Inbred C57BL; Mice, Transgenic; Osteocytes; Osteogenesis; Osteoporosis; Oxygen; Primary Cell Culture; Promoter Regions, Genetic; Sirtuin 1; Wnt Signaling Pathway

Hepatic fibrosis is a potential health problem that may end with life-threatening cirrhosis and primary liver cancer. Recent studies point out to the protective effects of silent information regulator1 (SIRT1), against different models of organs fibrosis. This work aimed to investigate the possible protective effect of sildenafil (SIRT1 activator) against hepatic fibrosis induced by bile duct ligation (BDL). Firstly, three different doses of sildenafil (5, 10, 20mg/kg/day) were investigated; to detect the most protective one against BDL induced liver dysfunction and hepatic fibrosis. The most protective dose is then used; to study its effect on BDL induced SIRT1 downregulation, imbalance of oxidant/antioxidant status, increased inflammatory cytokines and fibrosis. Sildenafil (20mg/kg/day) was the most protective one, it caused upregulation of SIRT1, reduction of hepatic malondialdehyde (MDA) content, increase in expression of nuclear factor erythroid 2-related factor 2 (Nrf2), hemeoxygenease (HO)-1, reduced glutathione (GSH) content and superoxide dismutase (SOD) activity. Hepatic content of tumor necrosis factor-α (TNF-α) and nuclear factor κB (NFκB) expression & content displayed significant reductions with sildenafil treatment, Furthermore, sildenafil caused marked reductions of transforming growth factor (TGF)-β content, expression of plasminogen activator inhibitor-1 (PAI-1), matrix metalloproteinase-9 (MMP-9), tissue inhibitor of metalloproteinase-1 (TIMP-1), α-smooth muscle actin (α-SMA), fibronectin, collagen I (α1) and hydroxyproline content. However, sildenafil protective effects were significantly reduced by co-administration of EX527 (SIRT1 inhibitor). Our work showed, for the first time that, sildenafil has promising protective effects against BDL induced liver dysfunction and hepatic fibrosis. These effects may be, in part, mediated by up regulation of SIRT1.

Topics: Animals; Anti-Inflammatory Agents; Antioxidants; Biomarkers; Carbazoles; Cholestasis; Cytoprotection; Disease Models, Animal; Histone Deacetylase Inhibitors; Inflammation Mediators; Ligation; Liver; Liver Cirrhosis, Biliary; Male; Oxidative Stress; Protective Agents; Rats, Wistar; Signal Transduction; Sildenafil Citrate; Sirtuin 1; Up-Regulation

Salvianolic acid B (SalB), a water-soluble polyphenol extracted from Radix Salvia miltiorrhiza, has been reported to possess many pharmacological activities. This study investigated the hepatoprotective effects of SalB in chronic alcoholic liver disease (ALD) and explored the related signaling mechanisms. In vivo, SalB treatment significantly attenuated ethanol-induced liver injury by blocking the elevation of serum aminotransferase activities and markedly decreased hepatic lipid accumulation by reducing serum and liver triglyceride (TG) and total cholesterol (TC) levels. Moreover, SalB treatment ameliorated ethanol-induced hepatic inflammation by decreasing the levels of hepatotoxic cytokines such as tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6). Importantly, SalB pretreatment significantly increased the expression of SIRT1 and downregulated the expression of inflammatory mediator C-reactive protein (CRP) and lipoprotein carbohydrate response element-binding protein (ChREBP). In vitro, SalB significantly reversed ethanol-induced down-regulation of SIRT1 and increased CRP and ChREBP expression. Interestingly, the effects of SalB on SIRT1, CRP and ChREBP were mostly abolished by treatment with either SIRT1 siRNA or EX527, a specific inhibitor of SIRT1, indicating that SalB decreased CRP and ChREBP expression by activating SIRT1. SalB exerted anti-steatotic and anti-inflammatory effects against alcoholic liver injury by inducing SIRT1-mediated inhibition of CRP and ChREBP expression.

Topics: Animals; Anti-Inflammatory Agents; Basic Helix-Loop-Helix Leucine Zipper Transcription Factors; Benzofurans; Biomarkers; Carbazoles; Carrier Proteins; Chronic Disease; Cytokines; Cytoprotection; Disease Models, Animal; Dose-Response Relationship, Drug; Hep G2 Cells; Hepatocyte Nuclear Factor 1-alpha; Histone Deacetylase Inhibitors; Humans; Inflammation Mediators; Liver; Liver Diseases, Alcoholic; Male; Rats, Sprague-Dawley; RNA Interference; RNA, Small Interfering; Signal Transduction; Sirtuin 1; Transfection

MicroRNAs (miRNAs) are noncoding small RNAs that control gene expression at the posttranscriptional level. Some dysregulated miRNAs have been shown to play important roles in epileptogenesis. The aim of this study was to determine if miR-199a-5p regulates seizures and seizure damage by targeting the antiapoptotic protein silent information regulator 1 (SIRT1).. Hippocampal expression levels of miR-199a-5p, SIRT1, and acetylated p53 were quantified by quantitative real-time polymerase chain reaction (RT-PCR) and Western blotting in the acute, latent, and chronic stages of epilepsy in a rat lithium-pilocarpine epilepsy model. Silencing of miR-199a-5p expression in vivo was achieved by intracerebroventricular injection of antagomirs. The effects of targeting miR-199a-5p and SIRT1 protein on seizure and epileptic damage post-status epilepticus were assessed by electroencephalography (EEG) and immunohistochemistry, respectively.. miR-199a-5p expression was up-regulated, SIRT1 levels were decreased, and neuron loss and apoptosis were induced in epilepsy model rats compared with normal controls, as determined by up-regulation of acetylated p53 and cleaved caspase-3 expression. In vivo knockdown of miR-199a-5p by an antagomir alleviated the seizure-like EEG findings and protected against neuron damage, in accordance with up-regulation of SIRT1 and subsequent deacetylation of p53. Furthermore, the seizure-suppressing effect of the antagomir was partly SIRT1 dependent.. The results of this study suggest that silencing of miR-199a-5p exerts a seizure-suppressing effect in rats, and that SIRT1 is a direct target of miR-199a-5p in the hippocampus. The effect of miR-199a-5p on seizures and seizure damage is mediated via down-regulation of SIRT1. The miR-199a-5p/SIRT1 pathway may thus represent a potential target for the prevention and treatment of epilepsy and epileptic damage.

Topics: Animals; Anticonvulsants; Apoptosis; Argonaute Proteins; Carbazoles; Convulsants; Disease Models, Animal; Hippocampus; Lithium Chloride; Male; MicroRNAs; Neurons; Oligonucleotides, Antisense; Pilocarpine; Rats; Rats, Sprague-Dawley; Signal Transduction; Sirtuin 1; Status Epilepticus; Tumor Suppressor Protein p53; Up-Regulation

Depression is a recurring and life-threatening illness that affects up to 120 million people worldwide. In the present study, we show that chronic social defeat stress, an ethologically validated model of depression in mice, increases SIRT1 levels in the nucleus accumbens (NAc), a key brain reward region. Increases in SIRT1, a well characterized class III histone deacetylase, after chronic social defeat suggest a role for this enzyme in mediating depression-like behaviors. When resveratrol, a pharmacological activator of SIRT1, was directly infused bilaterally into the NAc, we observed an increase in depression- and anxiety-like behaviors. Conversely, intra-NAc infusions of EX-527, a SIRT1 antagonist, reduced these behaviors; EX-527 also reduced acute stress responses in stress-naive mice. Next, we increased SIRT1 levels directly in NAc by use of viral-mediated gene transfer and observed an increase in depressive- and anxiety-like behaviors when mice were assessed in the open-field, elevated-plus-maze, and forced swim tests. Using a Cre-inducible viral vector system to overexpress SIRT1 selectively in dopamine D1 or D2 subpopulations of medium spiny neurons (MSNs) in the NAc, we found that SIRT1 promotes depressive-like behaviors only when overexpressed in D1 MSNs, with no effect seen in D2 MSNs. Conversely, selective ablation of SIRT1 in the NAc using viral-Cre in floxed Sirt1 mice resulted in decreased depression- and anxiety-like behaviors. Together, these results demonstrate that SIRT1 plays an essential role in the NAc in regulating mood-related behavioral abnormalities and identifies a novel signaling pathway for the development of innovative antidepressants to treat major depressive disorders.. In this study, we demonstrate a pivotal role for SIRT1 in anxiety- and depression-like behaviors in the nucleus accumbens (NAc), a key brain reward region. We show that stress stably induces SIRT1 expression in this brain region and that altering SIRT1 activity using a pharmacological or genetic approach regulates anxiety- and depression-like behaviors. These results suggest that SIRT1 plays an essential role in regulating mood-related behaviors and introduces a novel signaling pathway for the development of innovative antidepressants to treat depression and other stress-related disorders. A recent groundbreaking publication by the CONVERGE Consortium (2015) identified a reproducible association of the SIRT1 locus with major depression in humans. Therefore, our results are timely and have significant translational relevance.

Topics: Animals; Antidepressive Agents; Carbazoles; Depression; Disease Models, Animal; Dopaminergic Neurons; Drug Delivery Systems; Exploratory Behavior; Food Preferences; Gene Expression Regulation; Male; Maze Learning; Mice; Mice, Inbred C57BL; Mice, Transgenic; Nucleus Accumbens; Receptors, Dopamine D1; Receptors, Dopamine D2; Sirtuin 1; Stress, Psychological; Swimming

Sepsis often results in damage to multiple organ systems, possibly due to severe mitochondrial dysfunction. Two members of the sirtuin family, SIRT1 and SIRT3, have been implicated in the reversal of mitochondrial damage. The aim of this study was to determine the role of SIRT1/3 in acute kidney injury (AKI) following sepsis in a septic rat model. After drug pretreatment and cecal ligation and puncture (CLP) model reproduction in the rats, we performed survival time evaluation and kidney tissue extraction and renal tubular epithelial cell (RTEC) isolation. We observed reduced SIRT1/3 activity, elevated acetylated SOD2 (ac-SOD2) levels and oxidative stress, and damaged mitochondria in RTECs following sepsis. Treatment with resveratrol (RSV), a chemical SIRT1 activator, effectively restored SIRT1/3 activity, reduced acetylated SOD2 levels, ameliorated oxidative stress and mitochondrial function of RTECs, and prolonged survival time. However, the beneficial effects of RSV were greatly abrogated by Ex527, a selective inhibitor of SIRT1. These results suggest a therapeutic role for SIRT1 in the reversal of AKI in septic rat, which may rely on SIRT3-mediated deacetylation of SOD2. SIRT1/3 activation could therefore be a promising therapeutic strategy to treat sepsis-associated AKI.

Topics: Acetylation; Acute Kidney Injury; Animals; Apoptosis; Carbazoles; Cecum; Disease Models, Animal; Enzyme Activation; Epithelial Cells; Female; Histone Deacetylase Inhibitors; Kidney Tubules; Ligation; Male; Mitochondria; Oxidative Stress; Punctures; Rats, Sprague-Dawley; Resveratrol; Sepsis; Signal Transduction; Sirtuin 1; Sirtuins; Stilbenes; Superoxide Dismutase

Gemcitabine remains the standard treatment for pancreatic cancer, although most patients acquire resistance to the therapy. Up-regulated in pancreatic cancer, SIRT1 is involved in tumorigenesis and drug resistance. However the mechanism through which SIRT1 regulates drug sensitivity in cancer cells is mainly unknown. We hypothesise that inhibiting SIRT1 activity may increase sensitivity of pancreatic cancer cells to gemcitabine treatment through the regulation of apototic cell death, cell cycle, epithelial-mesenschymal-transition (EMT) and senescence. We demonstrate that gemcitabine or 6-Chloro-2,3,4,9-tetrahydro-1 H-Carbazole-1-carboxamide (EX527) SIRT1 inhibitor reduces PANC-1 cell proliferation in vitro. EX527 enhanced sensitivity of PANC-1 cells to gemcitabine treatment through increased apoptosis. However, EX527 displayed no beneficial effect either as a monotreatment or in combination with gemcitabine in the modulation of cell cycle progression. Combination treatment did not reverse the two phenomena known to affect drug sensitivity, namely EMT and senescence, which are both induced by gemcitabine. Unexpectedly, EX527 promoted PANC-1 xenograft tumour growth in SCID mice compared to control group. Dual tX527 and gemcitabine displayed no synergistic effect compared to gemcitabine alone. The study reveals that SIRT1 is involved in chemoresistance and that inhibiting SIRT1 activity with EX527 sensitised PANC-1 cells to gemcitabine treatment in vitro. Sensitisation of cells is shown to be mainly through induction of micronuclei formation as a result of DNA damage and apoptosis in vitro. However, the absence of positive combinatorial effects in vivo indicates possible effects on cells of the tumor microenvironment and suggests caution regarding the clinical relevance of tissue culture findings with EX527.

Topics: Animals; Apoptosis; Carbazoles; Cell Line, Tumor; Cell Proliferation; Cellular Senescence; Deoxycytidine; Disease Models, Animal; Drug Synergism; Epithelial-Mesenchymal Transition; Gemcitabine; Gene Expression Regulation, Neoplastic; Histone Deacetylase Inhibitors; Humans; Male; Mice; Micronucleus Tests; Pancreatic Neoplasms; Sirtuin 1

Silent information regulator 1 (SIRT1), a histone deacetylase, has been suggested to be effective in ischemic brain diseases. Salvianolic acid B (SalB) is a polyphenolic and one of the active components of Salvia miltiorrhiza Bunge. Previous studies suggested that SalB is protective against ischemic stroke. However, the role of SIRT1 in the protective effect of SalB against cerebral ischemia has not been explored. In this study, the rat brain was subjected to middle cerebral artery occlusion (MCAO). Before this surgery, rats were intraperitoneally administrated SalB with or without EX527, a specific SIRT1 inhibitor. The infarct volume, neurological score and brain water content were assessed. In addition, levels of TNF-α and IL-1β in the brain tissues were detected by commercial ELISA kits. And the expression levels of SIRT, Ac-FOXO1, Bcl-2 and Bax were detected by Western blot. The results suggested that SalB exerted a cerebral-protective effect, as shown by reduced infarct volume, lowered brain edema and increased neurological scores. SalB also exerted anti-inflammatory effects as indicated by the decreased TNF-α and IL-1β levels in the brain tissue. Moreover, SalB upregulated the expression of SIRT1 and Bcl-2 and downregulated the expression of Ac-FOXO1 and Bax. These effects of SalB were abolished by EX527 treatment. In summary, our results demonstrate that SalB treatment attenuates brain injury induced by ischemic stoke via reducing apoptosis and inflammation through the activation of SIRT1 signaling.

Topics: Animals; Anti-Inflammatory Agents, Non-Steroidal; Apoptosis; Benzofurans; Brain; Brain Edema; Brain Ischemia; Carbazoles; Central Nervous System Agents; Disease Models, Animal; Infarction, Middle Cerebral Artery; Inflammation; Male; Neuroprotective Agents; Random Allocation; Rats, Sprague-Dawley; Severity of Illness Index; Sirtuin 1; Stroke; Treatment Outcome

Respiratory syncytial virus (RSV) is the major cause of lower respiratory tract infection in children worldwide. Sirtuin 1 (SIRT1), an NAD(+)-dependent deacetylase, has been associated with the induction of autophagy and the regulation of inflammatory mediators. We found that Sirt1 was upregulated in mouse lung after RSV infection. Infected animals that received EX-527, a selective SIRT1 inhibitor, displayed exacerbated lung pathology, with increased mucus production, elevated viral load, and enhanced Th2 cytokine production. Gene expression analysis of isolated cell populations revealed that Sirt1 was most highly upregulated in RSV-treated dendritic cells (DCs). Upon RSV infection, EX-527-treated DCs, Sirt1 small interfering RNA-treated DCs, or DCs from conditional knockout (Sirt1(f/f)-CD11c-Cre(+)) mice showed downregulated inflammatory cytokine gene expression and attenuated autophagy. Finally, RSV infection of Sirt1(f/f)-CD11c-Cre(+) mice resulted in altered lung and lymph node cytokine responses, leading to exacerbated pathology. These data indicate that SIRT1 promotes DC activation associated with autophagy-mediated processes during RSV infection, thereby directing efficient antiviral immune responses.

Topics: Animals; Autophagy; Carbazoles; Cytokines; Dendritic Cells; Disease Models, Animal; Gene Expression; Gene Expression Regulation; Mice; Mice, Knockout; Respiratory Syncytial Virus Infections; Respiratory Syncytial Viruses; Sirtuin 1

Multiple sclerosis (MS) is characterized by central nervous system inflammation and demyelination, and increasing evidence demonstrates significant neuronal damage also occurs and is associated with permanent functional impairment. Current MS therapies have limited ability to prevent neuronal damage, suggesting additional neuroprotective therapies are needed. Compounds that activate the NAD+-dependent SIRT1 deacetylase prevent neuronal loss in an autoimmune-mediated MS model, but the mechanism of this effect is unknown, and it is unclear whether SIRT1 activating compounds exert similar effects in demyelinating disease induced by other etiologies. We measured neuronal loss in C57BL/6 mice inoculated with a neurotropic strain of mouse hepatitis virus, MHV-A59, that induces an MS-like disease.. Oral treatment with the SIRT1 activating compound SRTAW04 significantly increased SIRT1 activity within optic nerves and prevented neuronal loss during optic neuritis, an inflammatory demyelinating optic nerve lesion that occurs in MS and its animal models. MHV-A59 induced neuronal loss was associated with reactive oxygen species (ROS) accumulation, and SRTAW04 treatment significantly reduced ROS levels while promoting increased expression of enzymes involved in mitochondrial function and reduction of ROS. SRTAW04 exerted similar protective effects in EAE spinal cords, with decreased demyelination.. Results demonstrate that SIRT1 activating compounds prevent neuronal loss in viral-induced demyelinating disease similar to their effects in autoimmune-mediated disease. One mechanism of this neuroprotective effect involves increasing mitochondrial biogenesis with reduction of oxidative stress. SIRT1 activators represent a potential neuroprotective therapy for MS. Understanding common mechanisms of these effects in distinct disease models will help identify targets for more specific therapies.

Topics: Analysis of Variance; Animals; Carbazoles; Demyelinating Autoimmune Diseases, CNS; Disease Models, Animal; Dose-Response Relationship, Drug; Female; Hepatitis Viruses; Hepatitis, Viral, Animal; Mice; Mice, Inbred C57BL; Neurons; Oxidative Stress; Sirtuin 1; Stilbamidines; Time Factors

Protein acetylation, which is central to transcriptional control as well as other cellular processes, is disrupted in Huntington's disease (HD). Treatments that restore global acetylation levels, such as inhibiting histone deacetylases (HDACs), are effective in suppressing HD pathology in model organisms. However, agents that selectively target the disease-relevant HDACs have not been available. SirT1 (Sir2 in Drosophila melanogaster) deacetylates histones and other proteins including transcription factors. Genetically reducing, but not eliminating, Sir2 has been shown to suppress HD pathology in model organisms. To date, small molecule inhibitors of sirtuins have exhibited low potency and unattractive pharmacological and biopharmaceutical properties. Here, we show that highly selective pharmacological inhibition of Drosophila Sir2 and mammalian SirT1 using the novel inhibitor selisistat (selisistat; 6-chloro-2,3,4,9-tetrahydro-1H-carbazole-1-carboxamide) can suppress HD pathology caused by mutant huntingtin exon 1 fragments in Drosophila, mammalian cells and mice. We have validated Sir2 as the in vivo target of selisistat by showing that genetic elimination of Sir2 eradicates the effect of this inhibitor in Drosophila. The specificity of selisistat is shown by its effect on recombinant sirtuins in mammalian cells. Reduction of HD pathology by selisistat in Drosophila, mammalian cells and mouse models of HD suggests that this inhibitor has potential as an effective therapeutic treatment for human disease and may also serve as a tool to better understand the downstream pathways of SirT1/Sir2 that may be critical for HD.

Topics: Animals; Carbazoles; Disease Models, Animal; Drosophila melanogaster; Drosophila Proteins; Enzyme Inhibitors; Female; Histone Deacetylases; Humans; Huntington Disease; Male; Mice; Mice, Inbred C57BL; PC12 Cells; Rats; Rats, Sprague-Dawley; Sirtuin 1; Sirtuins

D-Galactosamine/Lipopolysaccharide (D-GalN/LPS) is a well known model of hepatotoxicity that closely resembles acute liver failure (ALF) seen clinically. The role of sirtuin 1 in this model has not yet been documented. However, there have been a number of studies about the cytoprotective effects of resveratrol, a SIRT1 activator, in the liver. This study was aimed at elucidating the roles of SIRT1 protein expression or catalytic activity in D-GalN/LPS model of hepatotoxicity. ALF was induced in male Wistar rats by intraperitoneal injection of D-GalN and LPS. Some groups of animals were pretreated with resveratrol and/or EX-527 (SIRT1 inhibitor). The effects of these treatments were evaluated by biochemical and Western blot studies. D-GalN/LPS treatment was able to induce hepatotoxicity and significantly increase all markers of liver damage and lipid peroxidation. A dramatic decrease of SIRT1 levels in response to D-GalN/LPS treatment was also documented. Resveratrol pretreatment attenuated D-GalN/LPS-induced hepatotoxicity. EX-527 blocked the cytoprotective effects of resveratrol. However, both resveratrol and EX-527 pretreatments did not exhibit any significant effect on SIRT1 protein expression. Collectively, these results suggest that downregulation of SIRT1 expression is involved in the cytotoxic effects of D-GalN/LPS model and SIRT1 activity contributes to the cytoprotective effects of resveratrol in the liver.

Topics: Animals; Antioxidants; Carbazoles; Chemical and Drug Induced Liver Injury; Cytoprotection; Disease Models, Animal; Down-Regulation; Enzyme Inhibitors; Galactosamine; Lipid Peroxidation; Lipopolysaccharides; Liver; Male; Rats, Wistar; Resveratrol; Sirtuin 1; Stilbenes

We have recently demonstrated that inhibition of histone deacetylase (HDAC) Class I, II, and IV with nonspecific HDAC inhibitors improves survival in a mouse model of lethal cecal ligation and puncture (CLP). However, the consequence of HDAC Class III inhibition is unknown in this model. The aims of the present study were to explore the effect of EX-527, a selective Sirtuin 1 (SIRT1) inhibitor, on survival in the lethal model of CLP-sepsis and to assess the impact of the treatment on inflammatory cytokine production, coagulopathy, and bone marrow atrophy during severe sepsis.. For Experiment I, C57BL/6J mice were subjected to CLP and, 1 hour later, intraperitoneally injected with either EX-527 dissolved in dimethyl sulfoxide (DMSO) or DMSO only. Survival was monitored for 10 days. For Experiment II, 1 hour after CLP animals were randomly treated with (1) DMSO vehicle and (2) EX-527. Peritoneal fluid and blood samples were collected for measurement of cytokines, and blood was also used to evaluate coagulation status using thrombelastography. In addition, long bones (femurs and tibias) were examined to determine morphologic changes in the marrow by hematoxylin and eosin staining. For Experiment III, normal primary splenocytes were cultured and treated with lipopolysaccharide in the presence or absence of EX-527 to assess cytokine production.. EX-527 significantly improved survival (50% vs. 0% survival as compared to vehicle, p = 0.0007) and attenuated levels of cytokines tumor necrosis factor α and interleukin 6 in the blood and the peritoneal fluid compared with the vehicle control. It also decreased tumor necrosis factor α and interleukin 6 production by splenocytes in vitro. Selective inhibition of SIRT1 was associated with significant improvements in fibrin cross-linkage, platelet function, and clot rigidity but had no significant impact on the clot initiation parameters. Moreover, inhibition of SIRT1 was associated with a significant decrease in bone marrow atrophy.. Selective inhibition of Class III HDAC SIRT1 significantly improves survival, attenuates cytokine levels and sepsis-associated coagulopathy, and decreases bone marrow atrophy in a lethal mouse septic model.

Topics: Animals; Blood Coagulation; Carbazoles; Disease Models, Animal; Femur; Histone Deacetylase Inhibitors; Histone Deacetylases; Interleukin-6; Male; Mice, Inbred C57BL; Sepsis; Thrombelastography; Tibia; Tumor Necrosis Factor-alpha

Regeneration of blood vessels in ischemic neuronal tissue is critical to reduce tissue damage in diseases. In proliferative retinopathy, initial vessel loss leads to retinal ischemia, which can induce either regrowth of vessels to restore normal metabolism and minimize damage, or progress to hypoxia-induced sight-threatening pathologic vaso-proliferation. It is not well understood how retinal neurons mediate regeneration of vascular growth in response to ischemic insults. In this study we aim to investigate the potential role of Sirtuin 1 (Sirt1), a metabolically-regulated protein deacetylase, in mediating the response of ischemic neurons to regulate vascular regrowth in a mouse model of oxygen-induced ischemic retinopathy (OIR). We found that Sirt1 is highly induced in the avascular ischemic retina in OIR. Conditional depletion of neuronal Sirt1 leads to significantly decreased retinal vascular regeneration into the avascular zone and increased hypoxia-induced pathologic vascular growth. This effect is likely independent of PGC-1α, a known Sirt1 target, as absence of PGC-1α in knockout mice does not impact vascular growth in retinopathy. We found that neuronal Sirt1 controls vascular regrowth in part through modulating deacetylation and stability of hypoxia-induced factor 1α and 2α, and thereby modulating expression of angiogenic factors. These results indicate that ischemic neurons induce Sirt1 to promote revascularization into ischemic neuronal areas, suggesting a novel role of neuronal Sirt1 in mediating vascular regeneration in ischemic conditions, with potential implications beyond retinopathy.

Topics: Angiogenic Proteins; Animals; Animals, Newborn; Basic Helix-Loop-Helix Transcription Factors; Carbazoles; Cell Line; Disease Models, Animal; Ischemia; Mice; Mice, Inbred C57BL; Mice, Knockout; Neovascularization, Physiologic; Neurons; Organ Culture Techniques; Oxygen; Oxygen Inhalation Therapy; Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha; Protein Processing, Post-Translational; Regeneration; Retinal Ganglion Cells; Retinal Vessels; Retinopathy of Prematurity; RNA, Messenger; Sirtuin 1; Transcription Factors; Up-Regulation

Neurodegenerative tauopathies characterized by hyperphosphorylated tau include frontotemporal dementia and Parkinsonism linked to chromosome 17 (FTDP-17) and Alzheimer's disease (AD). Reducing tau levels improves cognitive function in mouse models of AD and FTDP-17, but the mechanisms regulating the turnover of pathogenic tau are unknown. We found that tau is acetylated and that tau acetylation prevents degradation of phosphorylated tau (p-tau). We generated two antibodies specific for acetylated tau and showed that tau acetylation is elevated in patients at early and moderate Braak stages of tauopathy. Histone acetyltransferase p300 was involved in tau acetylation and the class III protein deacetylase SIRT1 in deacetylation. Deleting SIRT1 enhanced levels of acetylated-tau and pathogenic forms of p-tau, probably by blocking proteasome-mediated degradation. Inhibiting p300 with a small molecule promoted tau deacetylation and eliminated p-tau associated with tauopathy. Modulating tau acetylation could be a new therapeutic strategy to reduce tau-mediated neurodegeneration.

Topics: Acetylation; Analysis of Variance; Animals; Animals, Newborn; Carbazoles; Cells, Cultured; Cerebral Cortex; Cycloheximide; Disease Models, Animal; Enzyme Inhibitors; Gene Expression Regulation; Humans; Immunoprecipitation; Mice; Mice, Transgenic; Models, Biological; Mutation; Neurons; p300-CBP Transcription Factors; Phosphorylation; Protein Synthesis Inhibitors; Rats; Rats, Sprague-Dawley; Sirtuin 1; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; tau Proteins; Tauopathies; Time Factors; Transfection; Ubiquitination