gw-501516 and Atherosclerosis

Peroxisome proliferator-activated receptors (PPAR) are implicated in the pathology of several metabolic diseases including obesity, diabetes, and atherosclerosis. PPAR agonists exert multiple lipid modifying actions which are beneficial to the prevention of atherosclerosis. Such benefits in lipid lowering actions include improvements in atherogenic dyslipidemia that seems to be particularly expressed in individuals at higher cardiovascular (CV) risk. In addition, the favorable effects of PPAR agonists on different cardio-metabolic parameters are established in several metabolic conditions, such as diabetes mellitus, insulin resistance, and heightened systemic inflammation. The goal of this review is to summarize the current evidence on PPAR agonists and their effects on atherogenic dyslipidemia and CV risk. The main findings indicate that PPAR agonists improve not only the lipid profile, but also lipoprotein subfractions associated with atherogenic dyslipidemia and other CV markers. However, future prospective studies are required to establish the long-term effects of such therapies on atherogenic lipoproteins and their benefit on CV outcomes.

Topics: Animals; Atherosclerosis; Cardiovascular Diseases; Clinical Trials as Topic; Dyslipidemias; Humans; Hypolipidemic Agents; Peroxisome Proliferator-Activated Receptors; Risk Factors; Thiazoles

Novel peroxisome proliferator-activated receptor (PPAR) modulators (selective PPAR modulators [SPPARMs]) and dual PPAR agonists may have an important role in the treatment of cardiometabolic disorders owing to lipid-modifying, insulin-sensitizing and anti-inflammatory effects.. This review summarizes the efficacy of new PPAR agonists and SPPARMs that are under development for the treatment of atherogenic dyslipidemia and non-alcoholic fatty liver disease (NAFLD).. ABT-335 is a new formulation of fenofibrate that has been approved for concomitant use with statins. K-877, a SPPARM-α with encouraging preliminary results in modulating atherogenic dyslipidemia, and INT131, a SPPARM-γ with predominantly insulin-sensitizing actions, may also have favorable lipid-modifying effects. Although the development of dual PPAR-α/γ agonists (glitazars) and the SPPARM-δ GW501516 has been abandoned because of safety issues, another SPPARM-δ (MBX-8025) and a dual PPAR-α/δ agonist (GFT-505) have shown promising efficacy in decreasing plasma triglyceride and increasing high-density lipoprotein cholesterol concentrations, as well as improving insulin sensitivity and liver function. The beneficial effects of GFT-505 are complemented by preclinical findings that indicate reduction of hepatic fat accumulation, inflammation and fibrosis, making it a promising candidate for the treatment of NAFLD/nonalcoholic steatohepatitis (NASH). Long-term trials are required to test the efficacy and safety of these new PPAR agonists in reducing cardiovascular outcomes and treating NAFLD/NASH.

Topics: Acetates; Animals; Atherosclerosis; Chalcones; Cholesterol, HDL; Dyslipidemias; Fatty Liver; Fenofibrate; Humans; Insulin Resistance; Lipoproteins, HDL; Non-alcoholic Fatty Liver Disease; Peroxisome Proliferator-Activated Receptors; Propionates; Quinolines; Sulfonamides; Thiazoles; Triazoles; Triglycerides

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

The identification of small molecule agonists for the nuclear receptor peroxisome proliferator-activated receptor beta/delta (PPAR-beta/delta, NR1C2) has enabled the characterization of this receptor's functions in preclinical models. Subsequently, a number of small molecule agonists of PPAR-beta/delta have been progressed into clinical trials.. This review will examine the major preclinical findings that underpin the hypothesis that PPAR-beta/delta agonists may be beneficial in treating dyslipidemia and Type 2 diabetes, as well as emerging clinical data with a variety of PPAR-beta/delta agonists.. The literature concerning preclinical experiments that combine in vivo and in vitro mechanistic studies are reviewed and compared with the results of the early clinical trials.. Thus far, the activities of the agonists seen in the clinic are broadly similar to those seen in preclinical models. However, it is still not known if PPAR-beta/delta agonists will truly be differentiated enough from current treatments to justify their use in treating dyslipidemia or Type 2 diabetes. Major challenges for the development of PPAR-beta/delta agonists exist and the path forward is as yet undefined.

Topics: Animals; Atherosclerosis; Clinical Trials as Topic; Diabetes Mellitus, Type 2; Dyslipidemias; Glucose; Humans; Insulin Resistance; Lipoproteins; PPAR delta; PPAR-beta; Propionates; Thiazoles

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

Peroxisome proliferator-activated receptors (PPARs) are nuclear receptors, which mediate glucose and lipid homeostasis by regulating the expression of a large number of transcription factors. Sphingomyelin synthase (SMS) is a key enzyme in the synthesis of sphingomyelin (SM), and its expression and activity have been reported to be associated with atherosclerosis (AS). Although there have been many functional PPAR and SMS studies on atherosclerosis in recent years, few have investigated the correlation between the activation of PPARδ and the activity of SMS. In his study, macrophage-induced foam cells were utilized to model important pathological changes that occur in AS. The influence of PPARδ agonism by GW501516 on SMS and its product molecule SM were measured. Results indicated that the activation of PPARδ was correlated in a positive manner with the activity of SMS2, and the content of SM was dose dependently increased by GW501516. Together, this study represents the first to suggest that PPARδ activation may be a potential risk of AS through enhancing activity of SMS2.

Topics: Atherosclerosis; Dose-Response Relationship, Drug; Foam Cells; Humans; Macrophages; Membrane Proteins; Nerve Tissue Proteins; PPAR delta; Sphingomyelins; Thiazoles; Transferases (Other Substituted Phosphate Groups)

The peroxisome proliferator-activated receptor delta (PPARδ) has been implicated in the modulation of vascular homeostasis. However, its roles in the apoptotic cell death of vascular smooth muscle cells (VSMCs) are poorly understood. Here, we demonstrate that PPARδ modulates oxidized low-density lipoprotein (oxLDL)-induced apoptosis of VSMCs through the transforming growth factor-β (TGF-β) and focal adhesion kinase (FAK) signaling pathways. Activation of PPARδ by GW501516, which is a specific ligand, significantly inhibited oxLDL-induced cell death and generation of reactive oxygen species in VSMCs. These inhibitory effects were significantly reversed in the presence of small interfering (si)RNA against PPARδ, or by blockade of the TGF-β or FAK signaling pathways. Furthermore, PPARδ-mediated recovery of FAK phosphorylation suppressed by oxLDL was reversed by SB431542, a specific ALK5 receptor inhibitor, indicating that a TGF-β/FAK signaling axis is involved in the action of PPARδ. Among the protein kinases activated by oxLDL, p38 mitogen-activated protein kinase was suppressed by ligand-activated PPARδ. In addition, oxLDL-induced expression and translocation of pro-apoptotic or anti-apoptotic factors were markedly affected in the presence of GW501516. Those effects were reversed by PPARδ siRNA, or inhibitors of TGF-β or FAK, which also suggests that PPARδ exerts its anti-apoptotic effect via a TGF-β/FAK signaling axis. Taken together, these findings indicate that PPARδ plays an important role in the pathophysiology of disease associated with apoptosis of VSMC, such as atherosclerosis and restanosis.

Topics: Animals; Apoptosis; Atherosclerosis; Cells, Cultured; Coronary Restenosis; Focal Adhesion Protein-Tyrosine Kinases; Lipoproteins, LDL; Muscle, Smooth, Vascular; Myocytes, Smooth Muscle; PPAR delta; Rats; RNA, Small Interfering; Signal Transduction; Thiazoles; Transforming Growth Factor beta

The peroxisome proliferator-activated receptor (PPAR) δ regulates systemic lipid homeostasis and inflammation. However, the ability of PPARδ agonists to improve the pathology of pre-established lesions and whether PPARδ activation is atheroprotective in the setting of insulin resistance have not been reported. Here, we examine whether intervention with a selective PPARδ agonist corrects metabolic dysregulation and attenuates aortic inflammation and atherosclerosis.. Low-density lipoprotein receptor knockout mice were fed a chow or a high-fat, high-cholesterol (HFHC) diet (42% fat, 0.2% cholesterol) for 4 weeks. For a further 8 weeks, the HFHC group was fed either HFHC or HFHC plus GW1516 (3 mg/kg per day). GW1516 significantly attenuated pre-established fasting hyperlipidemia, hyperglycemia, and hyperinsulinemia, as well as glucose and insulin intolerance. GW1516 intervention markedly reduced aortic sinus lesions and lesion macrophages, whereas smooth muscle α-actin was unchanged and collagen deposition enhanced. In aortae, GW1516 increased the expression of the PPARδ-specific gene Adfp but not PPARα- or γ-specific genes. GW1516 intervention decreased the expression of aortic proinflammatory M1 cytokines, increased the expression of the anti-inflammatory M2 cytokine Arg1, and attenuated the iNos/Arg1 ratio. Enhanced mitogen-activated protein kinase signaling, known to induce inflammatory cytokine expression in vitro, was enhanced in aortae of HFHC-fed mice. Furthermore, the HFHC diet impaired aortic insulin signaling through Akt and forkhead box O1, which was associated with elevated endoplasmic reticulum stress markers CCAAT-enhancer-binding protein homologous protein and 78kDa glucose regulated protein. GW1516 intervention normalized mitogen-activated protein kinase activation, insulin signaling, and endoplasmic reticulum stress.. Intervention with a PPARδ agonist inhibits aortic inflammation and attenuates the progression of pre-established atherosclerosis.

Topics: Animals; Anti-Inflammatory Agents; Aortitis; Atherosclerosis; Biomarkers; Blood Glucose; Cholesterol, Dietary; Diet, High-Fat; Disease Models, Animal; Dyslipidemias; Inflammation Mediators; Insulin; Insulin Resistance; Lipids; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; PPAR delta; Receptors, LDL; Signal Transduction; Thiazoles; Time Factors

Topics: Animals; Anti-Inflammatory Agents; Aortitis; Atherosclerosis; Insulin Resistance; Male; PPAR delta; Receptors, LDL; Thiazoles

Peroxisome proliferator-activated receptors (PPARs) are members of the nuclear receptor superfamily of ligand-activated transcriptional regulators. PPARdelta has an established role in metabolism, wound healing, and angiogenesis. However, little is known about its function in endothelial homeostasis. We investigated the role of PPARdelta and its co-activator, PPARgamma co-activator 1alpha (PGC1alpha), in vasculoprotection against oxidant-induced injury via induction of haem oxygenase-1.. En face confocal microscopy of murine aortas demonstrated that the PPARdelta-selective ligand GW501516 induced endothelial haem oxygenase-1 expression. In vitro PPARdelta ligands induced a significant increase in haem oxygenase-1 mRNA, protein, and enzyme activity, resulting in enhanced human endothelial cell protection against cellular stress induced by hydrogen peroxide or leptin. Moreover, adenoviral-mediated overexpression of haem oxygenase-1 increased PPARdelta promoter activity and mRNA levels, amplifying the effect of PPARdelta ligands through a positive feedback loop. Mutation of PPAR response element binding sites in the haem oxygenase-1 promoter/enhancer region revealed haem oxygenase-1 to be a direct PPARdelta target gene. Inhibition of either haem oxygenase-1 or PPARdelta abrogated PPARdelta ligand-induced endothelial cytoprotection. Furthermore, siRNA depletion of PGC1alpha demonstrated that this co-regulator acts as an essential PPARdelta transcriptional co-activator for haem oxygenase-1 induction by PPARdelta ligands and its subsequent cytoprotective actions.. We have identified an important relationship between PPARdelta, PGC1alpha, and haem oxygenase-1, demonstrating that haem oxygenase-1 induction plays an important role in cytoprotective actions of PPARdelta ligands in vascular endothelium. In light of the protective effects of haem oxygenase-1 against atherogenesis, we suggest that PPARdelta represents a potentially important therapeutic target in the vasculature.

Topics: Animals; Aorta; Apoptosis; Atherosclerosis; Cells, Cultured; Endothelial Cells; Enzyme Activation; Feedback, Physiological; Heat-Shock Proteins; Heme Oxygenase-1; Homeostasis; Humans; Ligands; Mice; Mice, Inbred C57BL; Oxidative Stress; Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha; PPAR delta; RNA, Small Interfering; Thiazoles; Transcription Factors; Transcriptional Activation; Umbilical Veins

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