gw-501516 and Inflammation

Peroxisome proliferator-activated receptors (PPARs) are members of the nuclear hormone receptor superfamily of ligand-activated transcription factors, which is composed of three members encoded by distinct genes: PPARα, PPARβ/δ, and PPARγ. The biological actions of PPARα and PPARγ and their potential as a cardiovascular therapeutic target have been extensively reviewed, whereas the biological actions of PPARβ/δ and its effectiveness as a therapeutic target in the treatment of hypertension remain less investigated. Preclinical studies suggest that pharmacological PPARβ/δ activation induces antihypertensive effects in direct [spontaneously hypertensive rat (SHR), ANG II, and DOCA-salt] and indirect (dyslipemic and gestational) models of hypertension, associated with end-organ damage protection. This review summarizes mechanistic insights into the antihypertensive effects of PPARβ/δ activators, including molecular and functional mechanisms. Pharmacological PPARβ/δ activation induces genomic actions including the increase of regulators of G protein-coupled signaling (RGS), acute nongenomic vasodilator effects, as well as the ability to improve the endothelial dysfunction, reduce vascular inflammation, vasoconstrictor responses, and sympathetic outflow from central nervous system. Evidence from clinical trials is also examined. These preclinical and clinical outcomes of PPARβ/δ ligands may provide a basis for the development of therapies in combating hypertension.

Topics: Animals; Antihypertensive Agents; Blood Pressure; Endothelium, Vascular; Fatty Acids; Gene Expression Regulation; Humans; Hypertension; Inflammation; Phenoxyacetates; PPAR delta; PPAR-beta; Rats; Rats, Inbred SHR; RGS Proteins; Sympathetic Nervous System; Thiazoles; Vasoconstriction; Vasodilation

Therapeutic strategies to alleviate the growing epidemic of insulin-resistant syndromes (obesity and type 2 diabetes) as well as the conferred cardiovascular disease risk remain sparse. The peroxisome proliferator-activated receptor δ (PPARδ) has emerged as a versatile regulator of lipid homeostasis and inflammatory signaling, making it an attractive therapeutic target for the treatment and prevention of type 2 diabetes and atherosclerosis.. PPARδ activation regulates lipid homeostasis and inflammatory signaling in a variety of cell types, conferring protection from metabolic disease and atherosclerosis. Specifically, PPARδ activation in the liver stimulates glucose utilization and inhibits gluconeogenesis, which improves insulin resistance and hyperglycemia. In macrophages, PPARδ-specific activation with synthetic agonists inhibits VLDL-induced triglyceride accumulation and inflammation. In mice, PPARδ agonists halt the progression of atherosclerosis and stabilize existing lesions by promoting an anti-inflammatory milieu within the diseased macrovasculature. In humans, PPARδ activation improves insulin sensitivity and reduces atherogenic dyslipidemia via a mechanism complementary to statin monotherapy.. Recent advances in the understanding of PPARδ reveal that activation of this receptor represents a multifaceted therapeutic strategy for the prevention and treatment of insulin-resistant syndromes and atherosclerosis.

Topics: Animals; Anti-Inflammatory Agents; Atherosclerosis; Clinical Trials as Topic; Dyslipidemias; Hepatocytes; Humans; Inflammation; Insulin Resistance; Liver; Macrophages; Mice; PPAR delta; Thiazoles

Non-alcoholic fatty liver disease (NAFLD) is a liver pathology with increasing prevalence due to the obesity epidemic. Hence, NAFLD represents a rising threat to public health. Currently, no effective treatments are available to treat NAFLD and its complications such as cirrhosis and liver cancer. Peroxisome proliferator-activated receptors (PPARs) are ligand-activated nuclear receptors which regulate lipid and glucose metabolism as well as inflammation. Here we review recent findings on the pathophysiological role of PPARs in the different stages of NAFLD, from steatosis development to steatohepatitis and fibrosis, as well as the preclinical and clinical evidence for potential therapeutical use of PPAR agonists in the treatment of NAFLD. PPARs play a role in modulating hepatic triglyceride accumulation, a hallmark of the development of NAFLD. Moreover, PPARs may also influence the evolution of reversible steatosis toward irreversible, more advanced lesions. Presently, large controlled trials of long duration are needed to assess the long-term clinical benefits of PPAR agonists in humans. This article is part of a Special Issue entitled Triglyceride Metabolism and Disease.

Topics: Clinical Trials as Topic; Fatty Liver; Gene Expression; Humans; Inflammation; Liver; Non-alcoholic Fatty Liver Disease; Peroxisome Proliferator-Activated Receptors; Thiazoles; Triglycerides

Topics: Endothelial Cells; Humans; Hydrogen Sulfide; Inflammation; PPAR delta; Sodium-Glucose Transporter 2; STAT3 Transcription Factor

A hallmark of advanced atherosclerosis is inadequate immunosuppression by regulatory T (Treg) cells inside atherosclerotic lesions. Dyslipidemia has been suggested to alter Treg cell migration by affecting the expression of specific membrane proteins, thereby decreasing Treg cell migration towards atherosclerotic lesions. Besides membrane proteins, cellular metabolism has been shown to be a crucial factor in Treg cell migration. We aimed to determine whether dyslipidemia contributes to altered migration of Treg cells, in part, by affecting cellular metabolism.. Dyslipidemia was induced by feeding Ldlr-/- mice a western-type diet for 16-20 weeks and intrinsic changes in Treg cells affecting their migration and metabolism were examined. Dyslipidemia was associated with altered mTORC2 signalling in Treg cells, decreased expression of membrane proteins involved in migration, including CD62L, CCR7, and S1Pr1, and decreased Treg cell migration towards lymph nodes. Furthermore, we discovered that diet-induced dyslipidemia inhibited mTORC1 signalling, induced PPARδ activation and increased fatty acid (FA) oxidation in Treg cells. Moreover, mass-spectrometry analysis of serum from Ldlr-/- mice with normolipidemia or dyslipidemia showed increases in multiple PPARδ ligands during dyslipidemia. Treatment with a synthetic PPARδ agonist increased the migratory capacity of Treg cells in vitro and in vivo in an FA oxidation-dependent manner. Furthermore, diet-induced dyslipidemia actually enhanced Treg cell migration into the inflamed peritoneum and into atherosclerotic lesions in vitro.. Altogether, our findings implicate that dyslipidemia does not contribute to atherosclerosis by impairing Treg cell migration as dyslipidemia associated with an effector-like migratory phenotype in Treg cells.

Topics: Animals; Atherosclerosis; Cell Movement; Cells, Cultured; Coculture Techniques; Diet, High-Fat; Disease Models, Animal; Dyslipidemias; Energy Metabolism; Fatty Acids; Inflammation; Inflammation Mediators; Mechanistic Target of Rapamycin Complex 1; Mechanistic Target of Rapamycin Complex 2; Mice, Knockout, ApoE; Oxidation-Reduction; Phenotype; Plaque, Atherosclerotic; PPAR gamma; Receptors, LDL; Signal Transduction; T-Lymphocytes, Regulatory; Thiazoles

Daily activities expose muscles to innumerable impacts, causing accumulated tissue damage and inflammation that impairs muscle recovery and function, yet the mechanism modulating the inflammatory response in muscles remains unclear. Our study suggests that Forkhead box A2 (FoxA2), a pioneer transcription factor, has a predominant role in the inflammatory response during skeletal muscle injury. FoxA2 expression in skeletal muscle is upregulated by fatty acids and peroxisome proliferator-activated receptors (PPARs) but is refractory to insulin and glucocorticoids. Using PPARβ/δ agonist GW501516 upregulates FoxA2, which in turn, attenuates the production of proinflammatory cytokines and reduces the infiltration of CD45+ immune cells in two mouse models of muscle inflammation, systemic LPS and intramuscular injection of carrageenan, which mimic localized exercise-induced inflammation. This reduced local inflammatory response limits tissue damage and restores muscle tetanic contraction. In line with these results, a deficiency in either PPARβ/δ or FoxA2 diminishes the action of the PPARβ/δ agonist GW501516 to suppress an aggravated inflammatory response. Our study suggests that FoxA2 in skeletal muscle helps maintain homeostasis, acting as a gatekeeper to maintain key inflammation parameters at the desired level upon injury. Therefore, it is conceivable that certain myositis disorders or other forms of painful musculoskeletal diseases may benefit from approaches that increase FoxA2 activity in skeletal muscle.

Topics: Animals; Cytokines; Gene Expression Regulation; Glucocorticoids; HEK293 Cells; Hepatocyte Nuclear Factor 3-beta; Homeostasis; Humans; Inflammation; Male; Mice; Mice, Inbred C57BL; Muscle, Skeletal; Myoblasts; PPAR delta; PPAR-beta; Signal Transduction; Thiazoles; Transcriptional Activation; Up-Regulation

The effects of peroxisome proliferator-activated receptor (PPAR)β/δ ophthalmic solution were investigated in a rat corneal alkali burn model. After alkali injury, GW501516 (PPARβ/δ agonist) or vehicle ophthalmic solution was topically instilled onto the rat's cornea twice a day until day 7. Pathological findings were evaluated, and real-time reverse transcription polymerase chain reaction was performed. GW501516 strongly suppressed infiltration of neutrophils and pan-macrophages, and reduced the mRNA expression of interleukin-6, interleukin-1β, tumor necrosis factor alpha, and nuclear factor-kappa B. On the other hand, GW501516 promoted infiltration of M2 macrophages, infiltration of vascular endothelial cells associated with neovascularization in the wounded area, and expression of vascular endothelial growth factor A mRNA. However, 7-day administration of GW501516 did not promote neovascularization in uninjured normal corneas. Thus, the PPARβ/δ ligand suppressed inflammation and promoted neovascularization in the corneal wound healing process. These results will help to elucidate the role of PPARβ/δ in the field of ophthalmology.

Topics: Animals; Corneal Injuries; Disease Models, Animal; Gene Expression Regulation; Inflammation; Interleukin-1beta; Interleukin-6; Male; Neovascularization, Physiologic; PPAR delta; PPAR-beta; Rats; Rats, Wistar; Thiazoles; Vascular Endothelial Growth Factor A

High activation of the angiotensin-converting enzyme (ACE)/(angiotensin-II type 1 receptor) AT1r axis is closely linked to pro-inflammatory effects and liver damage. The aim of this study was to evaluate the effects of the short-term administration of GW501516 on pro-inflammatory markers in white adipose tissue (WAT) and hepatic stellate cells (HSCs), lipogenesis and insulin resistance in the liver upon high-fructose diet (HFru)-induced ACE/AT1r axis activation. Three-month-old male C57Bl/6 mice were fed a standard chow diet or a HFru for 8 weeks. Then, the animals were separated randomly into four groups and treated with GW501516 for 3 weeks. Morphological variables, systolic blood pressure, and plasma determinations were analyzed. In the WAT, the ACE/AT1r axis and pro-inflammatory cytokines were assessed, and in the liver, the ACE/AT1r axis, HSCs, fatty acid oxidation, insulin resistance, and AMPK activation were evaluated. The HFru group displayed a high activation of the ACE/AT1r axis in both the WAT and liver; consequently, we detected inflammation and liver damage. Although GW501516 abolished the increased activation of the ACE/AT1r axis in the WAT, no differences were found in the liver. GW501516 blunted the inflammatory state in the WAT and reduced HSC activation in the liver. In addition, GW501516 alleviates damage in the liver by increasing the expression of the genes that regulate beta-oxidation and decreasing the expression of the genes and proteins that are involved in lipogenesis and gluconeogenesis. We conclude that GW501516 may serve as a therapeutic option for the treatment of a highly activated ACE/AT1r axis in WAT and liver.

Topics: Adipose Tissue, White; Animals; Fructose; Hepatic Stellate Cells; Inflammation; Insulin Resistance; Lipogenesis; Liver; Male; Mice; Mice, Inbred C57BL; PPAR delta; Renin-Angiotensin System; Thiazoles

Peritoneal fibrosis is a common consequence of long-term peritoneal dialysis (PD), and peritonitis is a factor in its onset. Agonist-bound peroxisome proliferator-activated receptors (PPARs) function as key regulators of energy metabolism and inflammation. Here, we examined the effects of PPARβ/δ agonist GW501516 on peritonitis in a rat peritoneal fibrosis model. Peritoneal fibrosis secondary to inflammation was induced into uremic rats by daily injection of Dianeal 4.25% PD solutions along with six doses of lipopolysaccharide before commencement of GW501516 treatment. Normal non-uremic rats served as control, and all rats were fed with a control diet or a GW501516-containing diet. Compared to control group, exposure to PD fluids caused peritoneal fibrosis that was accompanied by increased mRNA levels of monocyte chemoattractant protein-1, tumor necrotic factor-α, and interleukin-6 in the uremic rats, and these effects were prevented by GW501516 treatment. Moreover, GW501516 was found to attenuate glucose-stimulated inflammation in cultured rat peritoneal mesothelial cells via inhibition of transforming growth factor-β-activated kinase 1 (TAK1), and nuclear factor kappa B (NFκB) signaling pathway (TAK1-NFκB pathway), a main inflammation regulatory pathway. In conclusion, inhibition of TAK1-NFκB pathway with GW501516 may represent a novel therapeutic approach to ameliorate peritonitis-induced peritoneal fibrosis for patients on PD.

Topics: Animals; Cells, Cultured; Chemokine CCL2; Dietary Supplements; Disease Models, Animal; Glucose; I-kappa B Kinase; Inflammation; Interleukin-6; Lipopolysaccharides; Male; MAP Kinase Kinase Kinases; Peritoneal Dialysis; Peritoneal Fibrosis; Peritonitis; PPAR delta; PPAR-beta; Rats; Rats, Sprague-Dawley; RNA, Messenger; Thiazoles; Transcription Factor RelA; Tumor Necrosis Factor-alpha; Uremia

PPARδ is involved in the inflammatory response and its expression is induced by cytokines, however, limited knowledge has been produced regarding its regulation. Since recent findings have shown that microRNAs, which are small non-coding RNAs that regulate gene expression, are involved in the immune response, we set out to investigate whether PPARδ can be regulated by microRNAs expressed in monocytes. Bioinformatic analysis identified a putative miR-9 target site within the 3'-UTR of PPARδ that was subsequently verified to be functional using reporter constructs. Primary human monocytes stimulated with LPS showed a downregulation of PPARδ and its target genes after 4 h while the expression of miR-9 was induced. Analysis of pro-inflammatory (M1) and anti-inflammatory (M2) macrophages showed that human PPARδ mRNA as well as miR-9 expression was higher in M1 compared to M2 macrophages. Furthermore, treatment with the PPARδ agonist, GW501516, induced the expression of PPARδ target genes in the pro-inflammatory M1 macrophages while no change was observed in the anti-inflammatory M2 macrophages. Taken together, these data suggest that PPARδ is regulated by miR-9 in monocytes and that activation of PPARδ may be of importance in M1 pro-inflammatory but not in M2 anti-inflammatory macrophages in humans.

Topics: Base Sequence; Cells, Cultured; Gene Expression Regulation; HEK293 Cells; Humans; Inflammation; Lipopolysaccharides; Macrophages; Membrane Proteins; MicroRNAs; Molecular Sequence Data; Monocytes; Perilipin-2; PPAR delta; RNA, Messenger; Thiazoles; Up-Regulation

The peroxisome proliferator-activated receptor-δ (PPARδ) regulates a multitude of physiological processes associated with glucose and lipid metabolism, inflammation, and proliferation. One or more of these processes are potential risk factors for the ability of PPARδ agonists to promote tumorigenesis in the mammary gland. In this study, we describe a new transgenic mouse model in which activation of PPARδ in the mammary epithelium by endogenous or synthetic ligands resulted in progressive histopathologic changes that culminated in the appearance of estrogen receptor- and progesterone receptor-positive and ErbB2-negative infiltrating ductal carcinomas. Multiparous mice presented with mammary carcinomas after a latency of 12 months, and administration of the PPARδ ligand GW501516 reduced tumor latency to 5 months. Histopathologic changes occurred concurrently with an increase in an inflammatory, invasive, metabolic, and proliferative gene signature, including expression of the trophoblast gene, Plac1, beginning 1 week after GW501516 treatment, and remained elevated throughout tumorigenesis. The appearance of malignant changes correlated with a pronounced increase in phosphatidylcholine and lysophosphatidic acid metabolites, which coincided with activation of Akt and mTOR signaling that were attenuated by treatment with the mTOR inhibitor everolimus. Our findings are the first to show a direct role of PPARδ in the pathogenesis of mammary tumorigenesis, and suggest a rationale for therapeutic approaches to prevent and treat this disease.

Topics: Animals; Carcinogenesis; Carcinoma, Ductal; Epithelium; Female; Gene Expression; Genes, erbB-2; Inflammation; Inflammatory Breast Neoplasms; Mammary Neoplasms, Experimental; Metabolomics; Mice; Mice, Transgenic; Phenotype; PPAR delta; Proto-Oncogene Proteins c-akt; Receptors, Estrogen; Receptors, Progesterone; Thiazoles; TOR Serine-Threonine Kinases

Owing to its high fat content, the classical Western diet has a range of adverse effects on the heart, including enhanced inflammation, hypertrophy, and contractile dysfunction. Proinflammatory factors secreted by cardiac cells, which are under the transcriptional control of nuclear factor-κB (NF-κB), may contribute to heart failure and dilated cardiomyopathy. The underlying mechanisms are complex, since they are linked to systemic metabolic abnormalities and changes in cardiomyocyte phenotype. Peroxisome proliferator-activated receptors (PPARs) are transcription factors that regulate metabolism and are capable of limiting myocardial inflammation and hypertrophy via inhibition of NF-κB. Since PPARβ/δ is the most prevalent PPAR isoform in the heart, we analyzed the effects of the PPARβ/δ agonist GW501516 on inflammatory parameters. A high-fat diet induced the expression of tumor necrosis factor-α, monocyte chemoattractant protein-1, and interleukin-6, and enhanced the activity of NF-κB in the heart of mice. GW501516 abrogated this enhanced proinflammatory profile. Similar results were obtained when human cardiac AC16 cells exposed to palmitate were coincubated with GW501516. PPARβ/δ activation by GW501516 enhanced the physical interaction between PPARβ/δ and p65, which suggests that this mechanism may also interfere NF-κB transactivation capacity in the heart. GW501516-induced PPARβ/δ activation can attenuate the inflammatory response induced in human cardiac AC16 cells exposed to the saturated fatty acid palmitate and in mice fed a high-fat diet. This is relevant, especially taking into account that PPARβ/δ has been postulated as a potential target in the treatment of obesity and the insulin resistance state.

Topics: AMP-Activated Protein Kinases; Animals; Cell Line; Cells, Cultured; Dietary Fats; Heart; Humans; Inflammation; Lipids; Mice; Mice, Knockout; Myocardium; PPAR delta; PPAR-beta; Signal Transduction; Thiazoles; Transcription Factor RelA

The peroxisome proliferator-activated receptor (PPAR)delta has been implicated in the pathogenesis of atherogenic disorders. However, its physiological roles and functions in vascular smooth muscle cells (VSMCs) remain relatively unclear. In the present study, we show that the gene encoding transforming growth factor (TGF)-beta1 is a PPARdelta target in VSMCs. The PPARdelta activator GW501516 upregulates TGF-beta1 expression in a dose- and time-dependent manner. This induction is attenuated significantly by the presence of small interfering RNA against PPARdelta or GW9662, an inhibitor of PPARdelta. Furthermore, activated PPARdelta induces TGF-beta1 promoter activity by binding to the direct repeat-1 response element TGF-beta1-direct repeat-1. Mutations in the 5' or 3' half-sites of the response element totally abrogate transcriptional activation and PPARdelta binding, which suggests that this site is a novel type of PPARdelta response element. In addition, ligand-activated PPARdelta attenuated the promoter activity and expression of monocyte chemoattractant protein-1 induced by interleukin-1beta. These effects were significantly reduced in the presence of small interfering RNA against PPARdelta, anti-TGF-beta1 antibody, or a TGF-beta type I receptor inhibitor. Decreased monocyte chemoattractant protein-1 expression induced by PPARdelta was mediated by the effector of TGF-beta1, Smad3. Finally, administration of GW501516 to mice upregulated TGF-beta1, whereas the expression of proinflammatory genes including monocyte chemoattractant protein-1 was significantly attenuated in the thoracic aorta. Taken together, these results demonstrate the presence of a novel TGF-beta1-mediated pathway in the antiinflammatory activities of PPARdelta.

Topics: Animals; Atherosclerosis; Cells, Cultured; Gene Expression Regulation; Inflammation; Ligands; Mice; Muscle, Smooth, Vascular; PPAR delta; Rats; RNA, Messenger; Thiazoles; Transforming Growth Factor beta1; Up-Regulation

Endothelial activation is implicated in atherogenesis and diabetes. The role of peroxisome proliferator-activated receptor-delta (PPAR-delta) in endothelial activation remains poorly understood. In this study, we investigated the anti-inflammatory effect of PPAR-delta and the mechanism involved.. In human umbilical vein endothelial cells (HUVECs), the synthetic PPAR-delta ligands GW0742 and GW501516 significantly inhibited tumor necrosis factor (TNF)-alpha-induced expression of vascular cell adhesion molecule-1 and E-selectin (assayed by real-time RT-PCR and Northern blotting), as well as the ensuing endothelial-leukocyte adhesion. Activation of PPAR-delta upregulated the expression of antioxidant genes superoxide dismutase 1, catalase, and thioredoxin and decreased reactive oxygen species production in ECs. Chromatin immunoprecipitation assays showed that GW0742 switched the association of BCL-6, a transcription repressor, from PPAR-delta to the vascular cell adhesion molecule (VCAM)-1 promoter. Small interfering RNA reduced endogenous PPAR-delta expression but potentiated the suppressive effect of GW0742 on EC activation, which suggests that the nonliganded PPAR-delta may have an opposite effect.. We have demonstrated that ligand activation of PPAR-delta in ECs has a potent antiinflammatory effect, probably via a binary mechanism involving the induction of antioxidative genes and the release of nuclear corepressors. PPAR-delta agonists may have a potential for treating inflammatory diseases such as atherosclerosis and diabetes.

Topics: Catalase; Cells, Cultured; Endothelial Cells; Humans; Inflammation; Ligands; PPAR delta; Superoxide Dismutase; Superoxide Dismutase-1; Thiazoles; Thioredoxins; Umbilical Veins; Up-Regulation

Inflammatory mediators contribute to pancreatic beta cell death in type 1 diabetes. Beta cells respond to cytokine exposure by activating gene networks that alter cellular metabolism, induce chemokine release (thereby increasing insulitis), and cause apoptosis. We have previously shown by microarray analysis that exposure of INS-1E cells to IL-1beta + IFN-gamma induces the transcription factor peroxisome proliferator-activated receptor (Ppar)-delta and several of its target genes. PPAR-delta controls cellular lipid metabolism and is a major regulator of inflammatory responses. We therefore examined the role of PPAR-delta in cytokine-treated beta cells.. Primary beta cells that had been purified by fluorescence-activated cell sorting and INS-1E cells were cultured in the presence of the cytokines TNF-alpha, IL-1beta, or IL-1beta + IFN-gamma, or the synthetic PPAR-delta agonist GW501516. Gene expression was analysed by real-time PCR. PPAR-delta, monocyte chemoattractant protein (MCP-1, now known as CCL2) promoter and NF-kappaB activity were determined by luciferase reporter assays.. Exposure of primary beta cells or INS-1E cells to cytokines induced Ppar-delta mRNA expression and PPAR-delta-dependent CD36, lipoprotein lipase, acyl CoA synthetase and adipophilin mRNAs. Cytokines and the PPAR-delta agonist GW501516 also activated a PPAR-delta response element reporter in beta cells. Unlike immune cells, neither INS-1E nor beta cells expressed the transcriptional repressor B-cell lymphoma-6 (BCL-6). As a consequence, PPAR-delta activation by GW501516 did not decrease cytokine-induced Mcp-1 promoter activation or mRNA expression, as reported for macrophages. Transient transfection with a BCL-6 expression vector markedly reduced Mcp-1 promoter and NF-kappaB activities in beta cells.. Cytokines activate the PPAR-delta gene network in beta cells. This network does not, however, regulate the pro-inflammatory response to cytokines because beta cells lack constitutive BCL-6 expression. This may render beta cells particularly susceptible to propagating inflammation in type 1 diabetes.

Topics: Animals; Cell Line; Cell Survival; Cytokines; Glucose; Inflammation; Insulin; Insulin Secretion; Insulin-Secreting Cells; Male; PPAR delta; Proto-Oncogene Proteins c-bcl-6; Rats; Rats, Wistar; Signal Transduction; Thiazoles