PPARδ Agonist Research Articles

Peroxisome Proliferator-Activated Receptor δ Suppresses the Cytotoxicity of CD8+ T Cells by Inhibiting RelA DNA-Binding Activity.

The molecular mechanisms regulating CD8+ cytotoxic T lymphocytes (CTL) are not fully understood. Here, we show that the peroxisome proliferator-activated receptor δ (PPARδ) suppresses CTL cytotoxicity by inhibiting RelA DNA binding. Treatment of ApcMin/+ mice with the PPARδ agonist GW501516 reduced the activation of normal and tumor-associated intestinal CD8+ T cells and increased intestinal adenoma burden. PPARδ knockout or knockdown in CTLs increased their cytotoxicity against colorectal cancer cells, whereas overexpression of PPARδ or agonist treatment decreased it. Correspondingly, perforin, granzyme B, and IFNγ protein and mRNA levels were higher in PPARδ knockout or knockdown CTLs and lower in PPARδ overexpressing or agonist-treated CTLs. Mechanistically, we found that PPARδ binds to RelA, interfering with RelA-p50 heterodimer formation in the nucleus, thereby inhibiting its DNA binding in CTLs. Thus, PPARδ is a critical regulator of CTL effector function. Significance: Here, we provide the first direct evidence that PPARδ plays a critical role in suppressing the immune response against tumors by downregulating RelA DNA-binding activity. This results in decreased expression of perforin, granzyme B, and IFNγ. Thus, PPARδ may serve as a valuable target for developing future cancer immunotherapies.

Discovery of the therapeutic potential of PPARδ agonist bearing 1,3,4- thiadiazole in inflammatory disorders

As a defense mechanism against deleterious stimuli, inflammation plays a vital role in the development of many disorders, including atherosclerosis, inflammatory bowel disease, experimental autoimmune encephalomyelitis, septic and non-septic shock, and non-alcoholic fatty liver disease (NAFLD). Despite the serious adverse effects of extended usage, traditional anti-inflammatory medications, such as steroidal and non-steroidal anti-inflammatory medicines (NSAIDs), are commonly used for alleviating symptoms of inflammation. The PPARδ subtype of peroxisome proliferator-activated receptors (PPARs) has attracted interest because of its potential for reducing inflammation and related disorders. In this study, a series of 1,3,4-thiadiazole derivatives were designed, synthesized, and evaluated. Compound 11 exhibited potent PPARδ agonistic activity with EC50 values 20 nM and strong selectivity over PPARα and PPARγ. Furthermore, compound 11 demonstrated favorable in vitro and in vivo pharmacokinetic properties. In vivo experiments using labeled macrophages and paw thickness measurements confirmed compound 11’s potential to reduce macrophage infiltration and alleviate inflammation. These findings highlight compound 11 as a potent and promising therapeutic candidate for the treatment of acute inflammatory diseases and warrant further investigation to explore various biological roles.

KLF15 ATTENUATES LIPOPOLYSACCHARIDE-INDUCED APOPTOSIS AND INFLAMMATORY RESPONSE IN RENAL TUBULAR EPITHELIAL CELLS VIA PPARΔ.

Background: The kidney is the most commonly affected organ in sepsis patients, and Krüppel-like transcription factor 15 (KLF15) has a kidney-protective effect and is highly enriched in the kidneys. This study aims to explore the role of KLF15 in sepsis-related acute kidney injury. Methods: A septic injury model in HK2 cells was established through the administration of lipopolysaccharide (LPS), followed by the transfection of an overexpression plasmid for KLF15. Cell viability was assessed using Cell Counting Kit-8 assay, and apoptosis was measured via flow cytometry. The levels of inflammatory cytokines were detected using ELISA, and western blot assay was employed to assess the expression of KLF15, PPARδ, as well as inflammatory and apoptosis-related proteins. The interaction between KLF15 and PPARδ was confirmed through the utilization of online databases and immunoprecipitation experiments. The mechanism was further validated using PPARδ agonists and small interfering RNA. Results: LPS-induced HK2 cells showed downregulated expression of KLF15 and PPARδ, along with decreased viability, accompanied by increased levels of apoptosis, TNFα, IL-1β, and IL-6. Additionally, LPS upregulated the expression of Bax, cytoplasmic cytochrome C [Cytc (cyt)], Cox-2, and p-NF-κB-p65 in HK2 cells, while simultaneously downregulating the expression of Bcl2 and mitochondrial cytochrome c [Cytc (mit)]. immunoprecipitation experiment revealed a possible interaction between KLF15 and PPARδ in HK2 cells. Ov-KLF15, Ov-PPARδ, or administration of PPARδ agonists effectively alleviated the aforementioned alterations induced by LPS. However, interference with PPARδ significantly attenuated the protective effect of Ov-KLF15 on HK2 cells. Conclusion: KLF15 attenuates LPS-induced apoptosis and inflammatory responses in HK2 cells via PPARδ.

Effects of elafibranor on liver fibrosis and gut barrier function in a mouse model of alcohol-associated liver disease.

Alcohol-associated liver disease (ALD) is a leading cause of liver-related morbidity and mortality, but there are no therapeutic targets and modalities to prevent ALD-related liver fibrosis. Peroxisome proliferator activated receptor (PPAR) α and δ play a key role in lipid metabolism and intestinal barrier homeostasis, which are major contributors to the pathological progression of ALD. Meanwhile, elafibranor (EFN), which is a dual PPARα and PPARδ agonist, has reached a phase III clinical trial for the treatment of metabolic dysfunction-associated steatotic liver disease and primary biliary cholangitis. However, the benefits of EFN for ALD treatment is unknown. To evaluate the inhibitory effects of EFN on liver fibrosis and gut-intestinal barrier dysfunction in an ALD mouse model. ALD-related liver fibrosis was induced in female C57BL/6J mice by feeding a 2.5% ethanol (EtOH)-containing Lieber-DeCarli liquid diet and intraperitoneally injecting carbon tetrachloride thrice weekly (1 mL/kg) for 8 weeks. EFN (3 and 10 mg/kg/day) was orally administered during the experimental period. Histological and molecular analyses were performed to assess the effect of EFN on steatohepatitis, fibrosis, and intestinal barrier integrity. The EFN effects on HepG2 lipotoxicity and Caco-2 barrier function were evaluated by cell-based assays. The hepatic steatosis, apoptosis, and fibrosis in the ALD mice model were significantly attenuated by EFN treatment. EFN promoted lipolysis and β-oxidation and enhanced autophagic and antioxidant capacities in EtOH-stimulated HepG2 cells, primarily through PPARα activation. Moreover, EFN inhibited the Kupffer cell-mediated inflammatory response, with blunted hepatic exposure to lipopolysaccharide (LPS) and toll like receptor 4 (TLR4)/nuclear factor kappa B (NF-κB) signaling. EFN improved intestinal hyperpermeability by restoring tight junction proteins and autophagy and by inhibiting apoptosis and proinflammatory responses. The protective effect on intestinal barrier function in the EtOH-stimulated Caco-2 cells was predominantly mediated by PPARδ activation. EFN reduced ALD-related fibrosis by inhibiting lipid accumulation and apoptosis, enhancing hepatocyte autophagic and antioxidant capacities, and suppressing LPS/TLR4/NF-κB-mediated inflammatory responses by restoring intestinal barrier function.

Development of a Robust Read-Across Model for the Prediction of Biological Potency of Novel Peroxisome Proliferator-Activated Receptor Delta Agonists.

A robust predictive model was developed using 136 novel peroxisome proliferator-activated receptor delta (PPARδ) agonists, a distinct subtype of lipid-activated transcription factors of the nuclear receptor superfamily that regulate target genes by binding to characteristic sequences of DNA bases. The model employs various structural descriptors and docking calculations and provides predictions of the biological activity of PPARδ agonists, following the criteria of the Organization for Economic Co-operation and Development (OECD) for the development and validation of quantitative structure-activity relationship (QSAR) models. Specifically focused on small molecules, the model facilitates the identification of highly potent and selective PPARδ agonists and offers a read-across concept by providing the chemical neighbours of the compound under study. The model development process was conducted on Isalos Analytics Software (v. 0.1.17) which provides an intuitive environment for machine-learning applications. The final model was released as a user-friendly web tool and can be accessed through the Enalos Cloud platform's graphical user interface (GUI).

Complementary information concerning the suspected interindividual transmission of GW1516, a substance prohibited in sport, through intimate contact: a case report

PurposeInadvertent and/or unknowing exposure to drugs and drug residues has been frequently debated in situations of so-called adverse analytical finding (AAF) in the context of sports drug testing programs. Transfer of drug residues via unprotected intercourse is a conceivable scenario but scientific data and authentic case reports are scarce. Herein, investigations into two AAFs with the peroxisome proliferator-activated receptor delta (PPARδ) agonist GW1516 are reported and discussed.MethodsTo probe for a contamination scenario involving sexual intercourse, two assays were used to determine semenogelin in human urine, with one employing an immunochromatographic lateral flow approach and another based on liquid chromatography–tandem mass spectrometry. Further, drug-residue testing using patients’ ejaculate was conducted by utilizing liquid chromatography in conjunction with a triple quadrupole mass spectrometer, followed by re-analysis of suspect samples (i.e., samples indicating the presence of relevant compounds) using high resolution/high mass accuracy mass spectrometry.ResultsIn one case, but not the other, the possibility of intimate contact as the source of the AAF was confirmed after a thorough investigation of potential contamination scenarios. Subsequent research revealed analytical evidence for the presence of seminal fluid in one of the female athlete’s doping control urine samples, and the analysis of clinical ejaculate specimens provided first data on an authentic concentration level of GW1516 and its metabolites in human seminal fluid.ConclusionsThe combined facts substantiate the possibility of an AAF caused by unprotected sexual intercourse and the plausibility of the case-related arguments.

Activation of PPARδ in bone marrow endothelial progenitor cells improves their hematopoiesis-supporting ability after myelosuppressive injury

Dysfunctional bone marrow (BM) endothelial progenitor cells (EPCs) with high levels of reactive oxygen species (ROS) are responsible for defective hematopoiesis in poor graft function (PGF) patients with acute leukemia or myelodysplastic neoplasms post-allotransplant. However, the underlying mechanism by which BM EPCs regulate their intracellular ROS levels and the capacity to support hematopoiesis have not been well clarified. Herein, we demonstrated decreased levels of peroxisome proliferator-activated receptor delta (PPARδ), a lipid-activated nuclear receptor, in BM EPCs of PGF patients compared with those with good graft function (GGF). In vitro assays further identified that PPARδ knockdown contributed to reduced and dysfunctional BM EPCs, characterized by the impaired ability to support hematopoiesis, which were restored by PPARδ overexpression. Moreover, GW501516, an agonist of PPARδ, repaired the damaged BM EPCs triggered by 5-fluorouracil (5FU) in vitro and in vivo. Clinically, activation of PPARδ by GW501516 benefited the damaged BM EPCs from PGF patients or acute leukemia patients in complete remission (CR) post-chemotherapy. Mechanistically, we found that increased expression of NADPH oxidases (NOXs), the main ROS-generating enzymes, may lead to elevated ROS level in BM EPCs, and insufficient PPARδ may trigger BM EPC damage via ROS/p53 pathway. Collectively, we found that defective PPARδ contributes to BM EPC dysfunction, whereas activation of PPARδ in BM EPCs improves their hematopoiesis-supporting ability after myelosuppressive therapy, which may provide a potential therapeutic target not only for patients with leukemia but also for those with other cancers.

Seladelpar: New hope for patients with primary biliary cholangitis

The study by Hirschfield etal.1 demonstrated safety profile and clinicallysignificant effectiveness of the peroxisome proliferator-activatedreceptor delta (PPARδ) agonist seladelpar in patients with primary biliary cholangitis, highlighting its plausible use as a second-line treatment to reduce disease activity and pruritus.

Rapid investigating of phase I metabolites of SR9009 in vitro horse liver microsomes via feature-based molecular networking approach: Potential applications in doping control

SR9009, a peroxisome proliferator-activated receptor δ (PPARδ) agonist, is known for its potential benefits in energy homeostasis. It failed to receive the United States Food and Drug Administration (USFDA) approval and its illegal distribution has raised concerns. As a result, it has been classified as a prohibited substance by the World Anti-Doping Agency and the International Federation of Horseracing Authorities (IFHA). This study emphasizes the application of the in-silico molecular networking technology to analyze phase I drug metabolites in horses, distinguishing it from conventional methodologies in forensic science. Feature-based molecular networking (FBMN) analysis identified 15 metabolites, with novel major N-dealkylated metabolite (-C8H7NO4S), indicative of diverse metabolic modifications in horse liver microsomes incubation assay. Additionally, a proposed metabolic pathway of SR9009 in the in vitro assay was outlined, including the previously known dehydroxylated metabolite. Finally, the metabolic pathways included in this study were as follows: hydroxylation, dehydrogenation, N-dealkylation dihydroxylation, and combinations. Molecular networking provided insights into MS spectra connectivity, facilitating rapid interpretation and accurate detection of previously undiscovered metabolites. In conclusion, this study contributes to the understanding of SR9009 metabolism in horses and underscores the importance of advanced analytical techniques, such as molecular networking, in enhancing the accuracy and efficiency of metabolite analysis for forensic and doping control purposes.

Mavodelpar, a selective peroxisome proliferator-activated receptor delta (PPARδ) agonist, improves cellular bioenergetics in fibroblasts from patients with primary mitochondrial myopathy and complex I defiency

Mavodelpar, a selective peroxisome proliferator-activated receptor delta (PPARδ) agonist, improves cellular bioenergetics in fibroblasts from patients with primary mitochondrial myopathy and complex I defiency

PPARδ agonist protects against osteoarthritis by activating AKT/mTOR signaling pathway-mediated autophagy.

Osteoarthritis (OA) is the most prevalent degenerative joint disease, and PPARs are involved in its pathogenesis; however, the specific mechanisms by which changes in PPARδ impact the OA pathogenesis yet to be discovered. The purpose of this study was to ascertain how PPARδ affects the onset and development of OA. In vitro, we found that PPARδ activation ameliorated apoptosis and extracellular matrix (ECM) degradation in OA chondrocytes stimulated by IL-1β. In addition, PPARδ activation may modulate AKT/mTOR signaling to partially regulate chondrocyte autophagy and apoptosis. In vivo, injection of PPARδ agonist into the articular cavity improved ECM degradation, apoptosis and autophagy in rats OA models generated by destabilization medial meniscus (DMM), eventually delayed degeneration of articular cartilage. Thus, targeting PPARδ for OA treatment may be a possibility.

Highly potent and selective PPARδ agonist reverses memory deficits in mouse models of Alzheimer's disease.

Rationale: Alzheimer's disease (AD) is a progressive neurodegenerative disease accompanied by neurotoxicity, excessive inflammation, and cognitive impairment. The peroxisome proliferator-activated receptor (PPAR) δ is a potential target for AD. However, its regulatory mechanisms and therapeutic potential in AD remain unclear. We aimed to investigate if the activation of PPARδ using a highly selective and potent agonist could provide an effective therapeutic strategy against AD. Methods: We synthesized a novel PPARδ agonist, 5a, containing a selenazole group and determined the X-ray crystal structure of its complex with PPARδ. The drug-like properties of 5a were assessed by analyzing cytochrome P450 (CYP) inhibition, microsomal stability, pharmacokinetics, and mutagenicity. We investigated the anti-inflammatory effects of 5a using lipopolysaccharide (LPS)-stimulated BV-2 microglia and neuroinflammatory mouse model. The therapeutic efficacy of 5a was evaluated in AD mice with scopolamine-induced memory impairment and APP/PS1 by analyzing cognitive function, glial reactivity, and amyloid pathology. Results: Compound 5a, the most potent and selective PPARδ agonist, was confirmed to bind hPPARδ in a complex by X-ray crystallographic analysis. PPARδ activation using 5a showed potent anti-inflammatory effects in activated glial cells and mouse model of neuroinflammation. Administration of 5a inhibited amyloid plaque deposition by suppressing the expression of neuronal beta-site amyloid precursor protein cleaving enzyme 1 (BACE1), and reduced abnormal glial hyperactivation and inflammatory responses, resulting in improved learning and memory in the APP/PS1 mouse model of AD. Conclusion: We identified that specific activation of PPARδ provides therapeutic effects on multiple pathogenic phenotypes of AD, including neuroinflammation and amyloid deposition. Our findings suggest the potential of PPARδ as a promising drug target for treating AD.

Exercise alleviates diabetic kidney disease through PPARδ-CPT1α pathway-dependent fatty acid β-oxidation

<p>Diabetic kidney disease (DKD), a severe diabetic complication affecting approximately one-third of diabetic patients, is the leading cause of end-stage chronic kidney disease. The benefits of regular exercise for patients with DKD have been well documented, particularly in overweight patients with DKD. However, the underlying mechanisms are incompletely understood. The present study demonstrates that exercise improves kidney function in diabetic <i>db/db</i> mice through activating PPARδ-mediated fatty acid β-oxidation (FAO). Twelve-week treadmill running exercise improved kidney function in <i>db/db</i> mice. Metabolomics and transcriptomics profiling analysis collectively revealed that dysregulation of FAO in <i>db/db</i> mice was largely corrected by running exercise. KEGG pathway enrichment revealed that PPAR pathway, a critical signalling cascade in FAO and exercise, is involved in DKD, suggesting PPARδ activation protects renal function through promoting FAO. Which was confirmed by improved renal function and enhanced FAO in <i>db/db</i> mice treated with PPARδ agonist GW501516. Oppositely, PPARδ-specific inhibitor GSK0660 abolished exercise-mediated improvement in renal function and FAO. In combining with gene expression profiling data we identified CPT1α, the rate-limiting enzyme in fatty acid oxidation, was suppressed in the kidney of diabetic mice and reversed by exercise and the PPARδ agonist GW501516. The findings hint at a potential role for the PPARδ-CPT1α pathway in exercise-induced improvements in diabetic renal function and may warrant further exploration of the PPARδ-CPT1α pathway as a therapeutic target in DKD.</p>

Impact of Peroxisome Proliferator-Activated Receptor Agonists on Myosteatosis in the Context of Metabolic Dysfunction-Associated Steatotic Liver Disease.

Metabolic dysfunction-associated steatotic liver disease (MASLD), and more specifically steatohepatitis may be associated with fat infiltration of skeletal muscles which is known as myosteatosis. Pan-peroxisome proliferator-activated receptor (PPAR) agonists have been shown to promote metabolic dysfunction-associated steatohepatitis (MASH) remission. However, the effect of PPAR agonists on myosteatosis remains to be determined. The aim of this review is to evaluate the effect that PPAR agonists alone or in combination, have on myosteatosis in the context of MASLD. Original research reports concerning the impact of PPAR agonists on muscle fat in MASLD were screened from PUBMED and EMBASE databases following the PRISMA methodology. Eleven original manuscripts were included in this review. Two preclinical studies assessed the impact of the PPARα agonist on fat content in the quadriceps muscle and the liver by extracting triglycerides in rats fed a high-fat diet and in insulin-resistant mice. Both models showed muscle and liver triglyceride content reduction using WY14643. Fenofibrate had no significant impact on soleus intramyocellular lipids or liver fat content in insulin-resistant subjects based on proton magnetic resonance spectroscopy. Treatment with PPARδ agonists increased the expression of genes involved in fatty acid oxidation in two studies on muscle cell culture. PPARγ agonists were investigated in two preclinical studies and one clinical study using spectroscopy and computed tomography respectively. In the first preclinical study in Zucker diabetic fatty rats, rosiglitazone reduced muscle lipids and hepatic steatosis. In a second preclinical study using the same animal model, pioglitazone reduced tibialis anterior intramyocellular lipids. In contrast, computed tomography analyses in patients with type 2 diabetes revealed a surface area increase of low-density muscles (suggesting an increase in muscle fat content) after a one-year treatment with rosiglitazone. Varying combinations of PPAR agonists (cevoglitazar, fenofibrate/pioglitazone and muraglitazar) were evaluated in two preclinical studies and one clinical study. In rats, these treatments showed variable results for muscle and liver depending on the combinations studied. In type 2 diabetic patients, treatment with muraglitazar (a PPARα/γ agonist) reduced the intramyocellular lipid content of tibialis anterior as well as liver fat content following spectroscopy assessment. The combination of different PPAR agonists could have a positive impact on reducing myosteatosis, in addition to their effect on the liver. Some discrepancies could be explained by the different techniques used to assess muscle lipid content, the muscles assessed and the possible adipogenic effect of PPARγ agonists. Further clinical research is needed to fully assess the efficacy of these treatments on both MASLD progression and associated myosteatosis.

Seladelpar combined with complementary therapies improves fibrosis, inflammation, and liver injury in a mouse model of nonalcoholic steatohepatitis.

Seladelpar, a selective peroxisome proliferator-activated receptor δ (PPARδ) agonist, improves markers of hepatic injury in human liver diseases, but histological improvement of nonalcoholic steatohepatitis (NASH) and liver fibrosis has been challenging with any single agent. To discover how complementary agents could work with seladelpar to achieve optimal outcomes, this study evaluated a variety of therapeutics (alone and in combination) in a mouse model of NASH. Mice on a high-fat amylin liver NASH (AMLN) diet were treated for 12 wk with seladelpar, GLP-1-R (glucagon-like peptide-1 receptor) agonist liraglutide, apoptosis signal-regulating kinase 1 (ASK1) inhibitor selonsertib, farnesoid X receptor (FXR) agonist obeticholic acid, and with seladelpar in combination with liraglutide or selonsertib. Seladelpar treatment markedly improved plasma markers of liver function. Seladelpar alone or in combination resulted in stark reductions in liver fibrosis (hydroxyproline, new collagen synthesis rate, mRNA indices of fibrosis, and fibrosis staining) compared with vehicle and the other single agents. Robust reductions in liver steatosis were also observed. Seladelpar produced a reorganization of metabolic gene expression, particularly for those genes promoting peroxisomal and mitochondrial lipid oxidation. In summary, substantial improvements in NASH and NASH-induced fibrosis were observed with seladelpar alone and in combination with liraglutide in this model. Broad gene expression analysis suggests seladelpar should be effective in concert with diverse mechanisms of action.NEW & NOTEWORTHY NASH is a chronic, progressive, and increasingly problematic liver disease that has been resistant to treatment with individual therapeutics. In this study using a diet-induced mouse model of NASH, we found that the PPARδ agonist seladelpar reduced fibrosis and NASH pathology alone and in combinations with a GLP-1-R agonist (liraglutide) or an ASK1 inhibitor (selonsertib). Liver transcriptome analysis comparing each agent and coadministration suggests seladelpar should be effective in combination with a variety of therapeutics.

Inhibitory Effect of PPARδ Agonist GW501516 on Proliferation of Hypoxia-induced Pulmonary Arterial Smooth Muscle Cells by Regulating the mTOR Pathway.

This study aimed to investigate the effects of the peroxisome proliferator-activated receptor δ (PPARδ) agonist GW501516 on the proliferation of pulmonary artery smooth muscle cells (PASMCs) induced by hypoxia, in order to search for new drugs for the treatment and prevention of pulmonary vascular remodeling. PASMCs were incubated with different concentrations of GW501516 (10, 30, 100 nmol/L) under the hypoxic condition. The proliferation was determined by a CCK-8 assay. The cell cycle progression was analyzed by flow cytometry. The expression of PPARδ, S phase kinase-associated protein 2 (Skp2), and cell cycle-dependent kinase inhibitor p27 was detected by Western blotting. Then PASMCs were treated with 100 nmol/ L GW501516, 100 nmol/L mammalian target of rapamycin (mTOR) inhibitor rapamycin and/or 2 µmol/L mTOR activator MHY1485 to explore the molecular mechanisms by which GW501516 reduces the proliferation of PASMCs. The presented data demonstrated that hypoxia reduced the expression of PPARδ in an oxygen concentration- and time-dependent manner, and GW501516 decreased the proliferation of PASMCs induced by hypoxia by blocking the progression through the G0/G1 to S phase of the cell cycle. In accordance with these findings, GW501516 downregulated Skp2 and upregulated p27 in hypoxia-exposed PASMCs. Further experiments showed that rapamycin had similar effects as GW501516 in inhibiting cell proliferation, arresting the cell cycle, regulating the expression of Skp2 and p27, and inactivating mTOR in hypoxia-exposed PASMCs. Moreover, MHY1485 reversed all the beneficial effects of GW501516 on hypoxia-stimulated PASMCs. GW501516 inhibited the proliferation of PASMCs induced by hypoxia through blocking the mTOR/Skp2/p27 signaling pathway.

PPARδ activation improves cardiac mitochondrial homeostasis in desmin deficient mice but does not alleviate systolic dysfunction

Peroxisome proliferator-activated receptor (PPAR) δ is a major transcriptional regulator of cardiac energy metabolism with pleiotropic properties, including anti-inflammatory, anti-oxidative and cardioprotective action. In this study, we sought to investigate whether pharmacological activation of PPARδ via intraperitoneal administration of the selective ligand GW0742 could ameliorate heart failure and mitochondrial dysfunction that have been previously reported in a characterized genetic model of heart failure, the desmin null mice (Des−/−). Our studies demonstrate that treatment of Des−/− mice with the PPARδ agonist attenuated cardiac inflammation, fibrosis and cardiac remodeling. In addition, PPARδ activation alleviated oxidative stress in the failing myocardium as evidenced by decreased ROS levels. Importantly, PPARδ activation stimulated mitochondrial biogenesis, prevented mitochondrial and sarcoplasmic reticulum vacuolar degeneration and improved the mitochondrial intracellular distribution. Finally, PPARδ activation alleviated the mitochondrial respiratory dysfunction, prevented energy depletion and alleviated excessive autophagy and mitophagy in Des−/− hearts. Nevertheless, improvement of all these parameters did not suffice to overcome the significant structural deficiencies that desmin deletion incurs in cardiomyocytes and cardiac function did not improve significantly. In conclusion, pharmacological PPARδ activation in Des−/− hearts exerts protective effects during myocardial degeneration and heart failure by preserving the function and quality of the mitochondrial network. These findings implicate PPARδ agonists as a supplemental constituent of heart failure medications.

Design, Synthesis, and Anti-Inflammatory Evaluation of a Novel PPARδ Agonist with a 4-(1-Pyrrolidinyl)piperidine Structure.

Peroxisome proliferator-activated receptor δ (PPARδ) is considered to be a pharmaceutical target to treat metabolic diseases including atherosclerosis, but there is no PPARδ agonist available for clinical use. We have previously reported the discovery of piperidinyl/piperazinyl benzothiazole derivatives as a new series of PPARδ agonists using docking-based virtual screening methods. In the present study, we found that introduction of a pyrrolidine group into the 4-position of their central piperidine rings enhances hPPARδ activity and subtype selectivity. This led to the discovery of 21 having strong PPARδ agonist activity (EC50 = 3.6 nM) with excellent ADME properties. Furthermore, 21 significantly suppressed atherosclerosis progression by 50-60% with reduction of the serum level of MCP-1 in LDLr-KO mice.

Hydrogen sulfide ameliorates senescence in vascular endothelial cells through ameliorating inflammation and activating PPARδ/SGLT2/STAT3 signaling pathway.

Mounting evidence demonstrates that hydrogen sulfide (H 2S) promotes anti-inflammatory molecules and inhibits pro-inflammatory cytokines in endothelial cells (ECs). This study aims to investigate the favorable action of H 2S on endothelial function in senescence by inhibiting the production of inflammatory molecules. Senescent ECs exhibit a reduction in H 2S, endothelial nitric oxide synthase (eNOS) and peroxisome proliferator-activated receptor δ (PPARδ), coupled with increased inflammatory molecules, sodium glucose transporter type 2 (SGLT2) and phosphorylation of STAT3, which could be reversed by the administration of a slow but sustained release agent of H 2S, GYY4137. Decreased production of eNOS and upregulated p-STAT3 and SGLT2 levels in senescent ECs are reversed by replenishment of the SGLT2 inhibitor EMPA and the PPARδ agonist GW501516. The PPARδ antagonist GSK0660 attenuates eNOS expression and increases the production of p-STAT3 and SGLT2. However, supplementation with GYY4137 has no beneficial effect on GSK0660-treated ECs. GYY4137, GW501516 and EMPA preserve endothelial-dependent relaxation (EDR) in D-gal-treated aortae, while GSK0660 destroys aortic relaxation even with GYY4137 supplementation. In summary, senescent ECs manifest aggravated the expressions of the inflammatory molecules SGLT2 and p-STAT3 and decreased the productions of PPARδ, eNOS and CSE. H 2S ameliorates endothelial dysfunction through the anti-inflammatory effect of the PPARδ/SGLT2/p-STAT3 signaling pathway in senescent ECs and may be a potential therapeutic target for anti-ageing treatment.

PPARδ Agonist GW501516 Suppresses the TGF-β-Induced Profibrotic Response of Human Bronchial Fibroblasts from Asthmatic Patients.

The airway wall remodeling observed in asthma is associated with subepithelial fibrosis and enhanced activation of human bronchial fibroblasts (HBFs) in the fibroblast to myofibroblast transition (FMT), induced mainly by transforming growth factor-β (TGF-β). The relationships between asthma severity, obesity, and hyperlipidemia suggest the involvement of peroxisome proliferator-activated receptors (PPARs) in the remodeling of asthmatic bronchi. In this study, we investigated the effect of PPARδ ligands (GW501516 as an agonist, and GSK0660 as an antagonist) on the FMT potential of HBFs derived from asthmatic patients cultured in vitro. This report shows, for the first time, the inhibitory effect of a PPARδ agonist on the number of myofibroblasts and the expression of myofibroblast-related markers-α-smooth muscle actin, collagen 1, tenascin C, and connexin 43-in asthma-related TGF-β-treated HBF populations. We suggest that actin cytoskeleton reorganization and Smad2 transcriptional activity altered by GW501516 lead to the attenuation of the FMT in HBF populations derived from asthmatics. In conclusion, our data demonstrate that a PPARδ agonist stimulates antifibrotic effects in an in vitro model of bronchial subepithelial fibrosis. This suggests its potential role in the development of a possible novel therapeutic approach for the treatment of subepithelial fibrosis during asthma.