Activation Of Peroxisome Proliferator-activated Receptor Gamma Research Articles

Epithelial hypoxia maintains colonization resistance against Candida albicans

Antibiotic treatment promotes the outgrowth of intestinal Candida albicans, but the mechanisms driving this fungal bloom remain incompletely understood. We identify oxygen as a resource required for post-antibiotic C.albicans expansion. C.albicans depleted simple sugars in the ceca of gnotobiotic mice but required oxygen to grow on these resources invitro, pointing to anaerobiosis as a potential factor limiting growth in the gut. Clostridia species limit oxygen availability in the large intestine by producing butyrate, which activates peroxisome proliferator-activated receptor gamma (PPAR-γ) signaling to maintain epithelial hypoxia. Streptomycin treatment depleted Clostridia-derived butyrate to increase epithelial oxygenation, but the PPAR-γ agonist 5-aminosalicylic acid (5-ASA) functionally replaced Clostridia species to restore epithelial hypoxia and colonization resistance against C.albicans. Additionally, probiotic Escherichia coli required oxygen respiration to prevent a post-antibiotic bloom of C.albicans, further supporting the role of oxygen in colonization resistance. We conclude that limited access to oxygen maintains colonization resistance against C.albicans.

Assessment of anti-hyperglycemic and anti-hyperlipidemic effects of thiazolidine-2,4-dione derivatives in HFD-STZ diabetic animal model

Type 2 diabetes mellitus (T2DM) is a chronic endocrine/metabolic disorder characterized by elevated postprandial and fasting glycemic levels that result in disturbances in primary metabolism. In this study, we evaluated the metabolic effects of thiazolidine-2,4-dione derivatives in Wistar rats and Swiss mice that were fed a high-fat diet (HFD) for 4 weeks and received 90 mg/kg of streptozotocin (STZ) intraperitoneally as a T2DM model. The HFD consisted of 17% carbohydrate, 58% fat, and 25% protein, as a percentage of total kcal. The thiazolidine-2,4-dione derivatives treatments reduced fasting blood glucose (FBG) levels by an average of 23.98%–50.84%, which were also improved during the oral starch tolerance test (OSTT). Treatment with thiazolidine-2,4-dione derivatives also improved triglyceride (TG), low-density lipoprotein cholesterol (LDL-c), and total cholesterol levels (P < 0.05). The treatment intake has also shown a significant effect to modulate the altered hepatic and renal biomarkers. Further treatment with thiazolidine-2,4-dione derivatives for 28 days significantly ameliorated changes in appearance and metabolic risk factors, including favorable changes in histopathology of the liver, kidney, and pancreas compared with the HFD/STZ-treated group, suggesting its potential role in the management of diabetes. Thiazolidine-2,4-dione derivatives are a class of drugs that act as insulin sensitizers by activating peroxisome proliferator-activated receptor-gamma (PPAR-γ), a nuclear receptor that regulates glucose and lipid metabolism. The results of this study suggest that thiazolidine-2,4-dione derivatives may be a promising treatment option for T2DM by improving glycemic control, lipid metabolism, and renal and hepatic function.

Oral Supplementation of Phosphatidylcholine Attenuates the Onset of a Diet-Induced Metabolic Dysfunction–Associated Steatohepatitis in Female C57BL/6J Mice

Background & AimsChanges in phosphatidylcholine levels in liver have been associated with the development of metabolic dysfunction-associated steatotic liver disease (MASLD). Here, the effects of supplementing phosphatidylcholine on the development of early signs of metabolic dysfunction-associated steatohepatitis (MASH) were assessed. MethodsMale and female C57BL/6J mice were fed a liquid control or a fructose-, fat- and/or cholesterol-rich diet (FrFC) for 7 or 8 weeks. The diets of female mice were fortified +/- phosphatidylcholine (12.5 mg/g diet). In liver tissue and portal blood, indices of liver damage, inflammation, and bacterial endotoxemia were measured. J774A.1 cells and human monocytes pre-incubated with phosphatidylcholine (0.38 mM) were challenged with lipopolysaccharide (LPS, 50-100 ng/ml) +/- the peroxisome proliferator-activated receptor gamma (PPARγ) activator pioglitazone (10 μM) or +/- an liver receptor homolog 1 (LRH-1) antagonist 1-(3´-(1-(2-(4-Morpholinyl)ethyl)-1H-pyrazol-3-yl)-3-biphenylyl)ethanon (1-10 μM). ResultsIn FrFC-fed mice the development of fatty liver and beginning of inflammation was associated with significantly lower hepatic phosphatidylcholine levels when compared to controls. Supplementing phosphatidylcholine significantly attenuated the development of fatty liver and inflammation, being associated with a protection against the induction of PPARγ2, and activation of nuclear factor of kappa light polypeptide gene enhancer in B-cells inhibitor alpha (IκBα) while Lrh1 expression was unchanged. The protective effects of phosphatidylcholine on the LPS-induced activation of J774A.1 cells and human monocytes were significantly attenuated by the PPARγ activator pioglitazone and the LRH-1 antagonist. ConclusionsOur data suggest that phosphatidylcholine levels in liver are lower in early MASH in mice and that a supplementation of phosphatidylcholine can diminish the development of MASLD through mechanisms involving LRH-1/PPARγ2/NFκB signaling.

Pioglitazone treatment mitigates cardiovascular bioprosthetic degeneration in a chronic kidney disease model.

Chronic kidney disease (CKD) is a risk factor for the development of cardiovascular diseases, e.g., atherosclerosis and calcific aortic valve disease, leading inevitably to valve replacement surgery. CKD patients with bioprosthetic cardiovascular grafts, in turn, have a higher risk of premature graft degeneration. Peroxisome proliferator-activated receptor gamma (PPARγ) activation by pioglitazone has cardio-renal protective properties, and research using a heterotopic valve implantation model has shown anti-degenerative effects of PPARγ activation on bioprosthetic valved grafts (BVG) in rats. The present work aims to analyze a potential protective effect of pioglitazone treatment on BVG in an adenine-induced rat model of CKD. BVG of Sprague Dawley rats were heterotopically implanted in Wistar rats in an infrarenal position for 4 and 8weeks. Animals were distributed into three groups for each time point: 1) control group receiving standard chow, 2) CKD group receiving 0.25% adenine and 3) CKD + pioglitazone group (300mg per kg of 0.25% adenine chow). BVG function was analyzed by echocardiography. Plasma analytes were determined and explanted grafts were analyzed by semi-quantitative real-time PCR, Western blot analysis, histology and immunohistology.PPARγ activation significantly reduced CKD-induced calcification of aortic and valvular segments of BVG by 44% and 53%, respectively. Pioglitazone treatment significantly also reduced CKD-induced intima hyperplasia by 60%. Plasma analysis revealed significantly attenuated potassium and phosphate levels after pioglitazone treatment. Moreover, PPARγ activation led to significantly decreased interleukin-6 gene expression (by 57%) in BVG compared to CKD animals. Pioglitazone treatment leads to functional improvement of BVG. This study broadens the understanding of the potential value of PPARγ activation in cardio-renal diseases and delineates pioglitazone treatment as a valuable option to prevent bioprosthetic graft failure in CKD. Further mechanistic studies, e.g., using small molecules activating PPARγ signaling pathways, are necessary for the evaluation of involved mechanisms. Additionally, the translation into pre-clinical studies using large animals is intended as the next research project.

Red Cabbage Juice-Mediated Gut Microbiota Modulation Improves Intestinal Epithelial Homeostasis and Ameliorates Colitis.

Gut microbiota plays a crucial role in inflammatory bowel diseases (IBD) and can potentially prevent IBD through microbial-derived metabolites, making it a promising therapeutic avenue. Recent evidence suggests that despite an unclear underlying mechanism, red cabbage juice (RCJ) alleviates Dextran Sodium Sulfate (DSS)-induced colitis in mice. Thus, the study aims to unravel the molecular mechanism by which RCJ modulates the gut microbiota to alleviate DSS-induced colitis in mice. Using C57BL/6J mice, we evaluated RCJ's protective role in DSS-induced colitis through two cycles of 3% DSS. Mice were daily gavaged with PBS or RCJ until the endpoint, and gut microbiota composition was analyzed via shotgun metagenomics. RCJ treatment significantly improved body weight (p ≤ 0.001), survival in mice (p < 0.001) and reduced disease activity index (DAI) scores. Further, RCJ improved colonic barrier integrity by enhancing the expression of protective colonic mucins (p < 0.001) and tight junction proteins (p ≤ 0.01) in RCJ + DSS-treated mice compared to the DSS group. Shotgun metagenomic analysis revealed an enrichment of short-chain fatty acids (SCFAs)-producing bacteria (p < 0.05), leading to increased Peroxisome Proliferator-Activated Receptor Gamma (PPAR-γ) activation (p ≤ 0.001). This, in turn, resulted in repression of the nuclear factor κB (NFκB) signaling pathway, causing decreased production of inflammatory cytokines and chemokines. Our study demonstrates colitis remission in a DSS-induced mouse model, showcasing RCJ as a potential modulator for gut microbiota and metabolites, with promising implications for IBD prevention and treatment.

Lung cancer progression alters lung and gut microbiomes and lipid metabolism

Despite advances in medical technology, lung cancer still has one of the highest mortality rates among all malignancies. Therefore, efforts must be made to understand the precise mechanisms underlying lung cancer development. In this study, we conducted lung and gut microbiome analyses and a comprehensive lipid metabolome analysis of host tissues to assess their correlation. Alternations in the lung microbiome due to lung cancer, such as a significantly decreased abundance of Firmicutes and Deferribacterota, were observed compared to a mock group. However, mice with lung cancer had significantly lower relative abundances of Actinobacteria and Proteobacteria and higher relative abundances of Cyanobacteria and Patescibacteria in the gut microbiome. The activations of retinol, fatty acid metabolism, and linoleic acid metabolism metabolic pathways in the lung and gut microbiomes was inversely correlated. Additionally, changes occurred in lipid metabolites not only in the lungs but also in the blood, small intestine, and colon. Compared to the mock group, mice with lung cancer showed that the levels of adrenic, palmitic, stearic, and oleic (a ω-9 polyunsaturated fatty acid) acids increased in the lungs. Conversely, these metabolites consistently decreased in the blood (serum) and colon. Leukotriene B4 and prostaglandin E2 exacerbate lung cancer, and were upregulated in the lungs of the mice with lung cancer. However, isohumulone, a peroxisome proliferator-activated receptor gamma activator, and resolvin (an ω-3 polyunsaturated fatty acid) both have anti-cancer effects, and were upregulated in the small intestine and colon. Our multi-omics data revealed that shifts in the microbiome and metabolome occur during the development of lung cancer and are of possible clinical importance. These results reveal one of the gut-lung axis mechanisms related to lung cancer and provide insights into potential new targets for lung cancer treatment and prophylaxis.

PPARG dysregulation as a potential molecular target in adrenal Cushing's syndrome.

We performed a transcriptomic analysis of adrenal signaling pathways in various forms of endogenous Cushing's syndrome (CS) to define areas of dysregulated and druggable targets. Next-generation sequencing was performed on adrenal samples of patients with primary bilateral macronodular adrenal hyperplasia (PBMAH, n=10) and control adrenal samples (n=8). The validation groups included cortisol-producing adenoma (CPA, n=9) and samples from patients undergoing bilateral adrenalectomy for Cushing's disease (BADX-CD, n=8). In vivo findings were further characterized using three adrenocortical cell-lines (NCI-H295R, CU-ACC2, MUC1). Pathway mapping based on significant expression patterns identified PPARG (peroxisome proliferator-activated receptor gamma) pathway as the top hit. Quantitative PCR (QPCR) confirmed that PPARG (l2fc<-1.5) and related genes - FABP4 (l2fc<-5.5), PLIN1 (l2fc<-4.1) and ADIPOQ (l2fc<-3.3) - were significantly downregulated (p<0.005) in PBMAH. Significant downregulation of PPARG was also found in BADX-CD (l2fc<-1.9, p<0.0001) and CPA (l2fc<-1.4, p<0.0001). In vitro studies demonstrated that the PPARG activator rosiglitazone resulted in decreased cell viability in MUC1 and NCI-H295R (p<0.0001). There was also a significant reduction in the production of aldosterone, cortisol, and cortisone in NCI-H295R and in Dihydrotestosterone (DHT) in MUC1 (p<0.05), respectively. This therapeutic effect was independent of the actions of ACTH, postulating a promising application of PPARG activation in endogenous hypercortisolism.

Pioglitazone-Enhanced Brown Fat Whitening Contributes to Weight Gain in Diet-Induced Obese Mice.

Pioglitazone is an insulin sensitizer used for the treatment of type 2 diabetes mellitus (T2DM) by activating peroxisome proliferator-activated receptor gamma. This study aimed to investigate the effects of pioglitazone on white adipose tissue (WAT) and brown adipose tissue (BAT) in diet-induced obese (DIO) mice. C57BL/6 mice were treated with pioglitazone (30 mg/kg/day) for 4 weeks after a 16-week high-fat diet (HFD) challenge. Body weight gain, body fat mass, energy intake, and glucose homeostasis were measured during or after the treatment. Histopathology was observed by hematoxylin and eosin, oil red O, immunohistochemistry, and immunofluorescence staining. Expression of thermogenic and mitochondrial biogenesis-related genes was detected by quantitative real-time PCR and western blotting. After 4-week pioglitazone treatment, the fasting blood glucose levels, glucose tolerance, and insulin sensitivity were significantly improved, but the body weight gain and fat mass were increased in DIO mice. Compared with the HFD group, pioglitazone did not significantly affect the weights of liver and WAT in both subcutaneous and epididymal regions. Unexpectedly, the weight of BAT was increased after pioglitazone treatment. Histological staining revealed that pioglitazone ameliorated hepatic steatosis, reduced the adipocyte size in WAT, but increased the adipocyte size in BAT. Though pioglitazone can promote lipolysis, thermogenesis, and mitochondrial function in WAT, it leads to impaired thermogenesis, and mitochondrial dysfunction in BAT. In conclusion, pioglitazone could promote the browning of WAT but led to the whitening of BAT; the latter might be a new potential mechanism of pioglitazone-induced weight gain during T2DM treatment.

Preventive Effect of Molecular Iodine in Pancreatic Disorders from Hypothyroid Rabbits.

Pancreatic alterations such as inflammation and insulin resistance accompany hypothyroidism. Molecular iodine (I2) exerts antioxidant and differentiation actions in several tissues, and the pancreas is an iodine-uptake tissue. We analyzed the effect of two oral I2 doses on pancreatic disorders in a model of hypothyroidism for 30 days. Adult female rabbits were divided into the following groups: control, moderate oral dose of I2 (0.2 mg/kg, M-I2), high oral dose of I2 (2.0 mg/kg, H-I2), oral dose of methimazole (MMI; 10 mg/kg), MMI + M-I2,, and MMI + H-I2. Moderate or high I2 supplementation did not modify circulating metabolites or pancreatic morphology. The MMI group showed reductions of circulating thyroxine (T4) and triiodothyronine (T3), moderate glucose increments, and significant increases in cholesterol and low-density lipoproteins. Acinar fibrosis, high insulin content, lipoperoxidation, and overexpression of GLUT4 were observed in the pancreas of this group. M-I2 supplementation normalized the T4 and cholesterol, but T3 remained low. Pancreatic alterations were prevented, and nuclear factor erythroid-2-related factor-2 (Nrf2), antioxidant enzymes, and peroxisome proliferator-activated receptor gamma (PPARG) maintained their basal values. In MMI + H-I2, hypothyroidism was avoided, but pancreatic alterations and low PPARG expression remained. In conclusion, M-I2 supplementation reestablishes thyronine synthesis and diminishes pancreatic alterations, possibly related to Nrf2 and PPARG activation.

FRI026 PPARγ Antagonists Induce Aromatase Transcription In Human Adipose Tissue Cells

Abstract Disclosure: J. Ardenkjær-Skinnerup: None. P.S. Petersen: None. N. Hadrup: None. G. Ravn-Haren: None. B. Emanuelli: None. U.B. Vogel: None. K.A. Brown: None. Peroxisome proliferator-activated receptor gamma (PPARγ) activation in adipose stromal cells (ASCs; adipocyte precursors) is associated with decreased expression of the estrogen biosynthetic enzyme, aromatase, encoded by the CYP19A1 gene. A number of chemicals and endocrine disruptors can affect PPARγ function. For example, ethanol-mediated inhibition of PPARγ activity is associated with increased risk of breast cancer,1 and a potential mechanism has been suggested to involve upregulation of aromatase. It is therefore hypothesized that inhibitors of PPARγ will induce aromatase expression and may act as breast carcinogens. This study aimed to explore the effect of PPARγ antagonists on the expression of aromatase in cells from human adipose tissue. Human adipose tissue was obtained from abdominoplasty or reduction mammoplasty surgeries. Explants, adipocytes and ASCs were collected for culture and/or gene expression analysis. Primary ASCs and the hTERT A41 hWAT ASC line were differentiated in the presence of PPARγ antagonists followed by gene expression analysis or lipid staining. Adipose tissue explants and A41 cells were treated for 24 or 48 h with PPARγ agonist or antagonist, and gene expression analysis was performed. Finally, PPARγ was overexpressed in A41 cells and/or treated with a PPARγ agonist to study the effect of PPARγ protein level and activation on aromatase expression. Aromatase expression was higher in human ASCs than in mature adipocytes. Exposure of ASCs to PPARγ antagonists during differentiation inhibited lipid accumulation and resulted in higher expression of aromatase. PPARγ overexpression and agonist treatment repressed aromatase expression in A41 cells, while antagonist treatment in differentiated A41 cells resulted in increased aromatase expression. A similar tendency was observed in adipose tissue explants. In conclusion, the results suggest that PPARγ regulates aromatase through two separate mechanisms. Exposure of human ASCs to PPARγ antagonists indirectly upregulates aromatase expression by inhibition of adipogenesis. In addition, PPARγ regulates aromatase in differentiated ASCs via a more acute mechanism, not related to adipocyte differentiation. 1. Petersen RK, Larsen SB, Jensen DM, et al. PPARgamma-PGC-1alpha activity is determinant of alcohol related breast cancer. Cancer Lett. 2012;315(1):59-68. Presentation: Friday, June 16, 2023

Intriguing Thiazolidinediones as PPAR γ Agonists: A Review

Diabetes mellitus is a chronic metabolic disorder marked by persistently elevated blood sugar levels. left untreatedover a long duration can cause multiple body disorders and may cause a person's early death. Though a traditional disorder, typeII diabetes prevalence is increasing daily, especially in the adolescent population worldwide. Peroxisome proliferator-activatedreceptor (PPAR) is a group of receptors consisting of three isoforms (PPAR α, PPAR β/δ, and PPAR γ. PPAR γ is involved inglucose metabolism by facilitating insulin's actions. Thiazolidinedione is a heterocyclic moiety standing pre-eminent in treatingdiabetes mellitus as a PPAR Gamma activator. Thiazolidinedione is a five-membered heterocyclic organic compound, athiazolidine derivative consisting of two carbonyl groups at positions 2 and 4 of the thiazolidine ring. Thiazolidinediones possessan idiosyncratic scaffold featuring a hydrogen bond acceptor region and hydrogen bond donating region at the third and fifthpositions. Thiazolidinedione is an indispensable pharmacophore with many pharmacological activities like antiproliferative,antiviral, antibacterial, tyrosine kinase inhibitory, aldose reductase inhibitory, alpha-glucosidase inhibitory, anti-inflammatory,antioxidant, antitubercular, antihyperlipidemic, etc. Many drugs have been introduced but later have been reticent because ofserious side effects like liver toxicity, CVS toxicity, etc. Pioglitazone and Rosiglitazone have been marketed medications fortreating type II diabetes. This review article deliberates all the cardinal points of thiazolidinediones as PPAR agonists in treatingdiabetes mellitus, which were precluded in some articles. We aim to have an all-embracing review of thiazolidinediones as PPARgamma agonists. The review's objective is to inspire researchers to develop a more superior, secure, and efficient anti-diabeticmedication by thoroughly understanding the molecular mechanisms of thiazolidinediones at the PPAR gamma receptors, theirrisks, and the effect of the various substitutions on the thiazolidinedione.

Angelica sinensis polysaccharide improves mitochondrial metabolism of osteoarthritis chondrocytes through PPARγ/SOD2/ROS pathways.

Osteoarthritis (OA) is a common degenerative joint disease, which is characterized by wear of articular cartilage and narrow joint space, resulting in joint movement disorder. At present, accurate molecular mechanisms and effective interventions are still being explored. Here, we propose that angelica sinensis polysaccharide (ASP) alleviates OA progression by activating peroxisome proliferator-activated receptor gamma (PPARγ). Therapeutic effect of ASP improving mitochondrial metabolism of OA chondrocytes was evaluated in vitro and in vivo, respectively. During cell experiments, the concentration and time response of tert butyl hydroperoxide (TBHP) and ASP were determined by cell viability. Apoptosis was detected by flow cytometry. Mitochondrial metabolism was detected by reactive oxygen species (ROS), mitochondrial membrane potential (MMP), release of cytochrome C, adenosine triphosphate (ATP) production, and superoxide dismutase 2 (SOD2) activity. Expressions of Aggrecan, collagen type II (Col2a1), PPARγ, and SOD2 were detected by qRT-PCR and western blot. In animal experiments, we detected cell apoptosis and target protein expression separately through terminal deoxynucleotidyl transferase dUTP nick end-labeling (TUNEL) staining and immunohistochemistry. Pretreatment of ASP significantly activated PPARγ and SOD2 in rat chondrocytes incubated with TBHP, cleared ROS, improved mitochondrial metabolism, increased chondrocytes viability, and alleviated chondrocytes apoptosis. In vivo, the administration of ASP could effectively ameliorate cartilage degeneration in OA rats, promote extracellular matrix synthesis, and decelerate the progress of OA. Our research identifies the role of ASP in mitochondrial metabolism of OA chondrocytes through PPARγ/SOD2/ROS pathways, which provides a new idea for the treatment of OA.

24-Norursodeoxycholic acid ameliorates experimental alcohol-related liver disease and activates hepatic PPARγ

Alcohol-related liver disease (ALD) is a global healthcare challenge with limited treatment options. 24-Norursodeoxycholic acid (NorUDCA) is a synthetic bile acid with anti-inflammatory properties in experimental and human cholestatic liver diseases. In the present study, we explored the efficacy of norUDCA in experimental ALD. NorUDCA was tested in a preventive and therapeutic setting in an experimental ALD model (Lieber-DeCarli diet enriched with ethanol). Liver disease was phenotypically evaluated using histology and biochemical methods, and anti-inflammatory properties and peroxisome proliferator-activated receptor gamma activation by norUDCA were evaluated in cellular model systems. NorUDCA administration ameliorated ethanol-induced liver injury, reduced hepatocyte death, and reduced the expression of hepatic pro-inflammatory cytokines including tumour necrosis factor (Tnf), Il-1β, Il-6, and Il-10. NorUDCA shifted hepatic macrophages towards an anti-inflammatory M2 phenotype. Further, norUDCA administration altered the composition of the intestinal microbiota, specifically increasing the abundance of Roseburia, Enterobacteriaceae, and Clostridum spp. In atherapeutic model, norUDCA also ameliorated ethanol-induced liver injury. Moreover, norUDCA suppressed lipopolysaccharide-induced IL-6 expression in human peripheral blood mononuclear cells and evoked peroxisome proliferator-activated receptor gamma activation. NorUDCA ameliorated experimental ALD, protected against hepatic inflammation, and affected gut microbial commensalism. NorUDCA could serve as a novel therapeutic agent in the future management of patients with ALD. Alcohol-related liver disease is a global healthcare concern with limited treatment options. 24-Norursodeoxycholic acid (NorUDCA) is a modified bile acid, which was proven to be effective in human cholestatic liver diseases. In the present study, we found a protective effect of norUDCA in experimental alcoholic liver disease. For patients with ALD, norUDCA could be a potential new treatment option.

Bisphenol A substitutes and obesity: a review of the epidemiology and pathophysiology.

The prevalence of obesity, a condition associated with increased health risks, has risen significantly over the past several decades. Although obesity develops from energy imbalance, its etiology involves a multitude of other factors. One of these factors are endocrine disruptors, or "obesogens", when in reference to obesity. Bisphenol A (BPA), a known endocrine disruptor used in plastic materials, has recently been described as an environmental obesogen. Although BPA-free products are becoming more common now than in the past, concerns still remain about the obesogenic properties of the compounds that replace it, namely Bisphenol S (BPS), Bisphenol F (BPF), and Bisphenol AF (BPAF). The purpose of this review is to investigate the relationship between BPA substitutes and obesity. Literature on the relationship between BPA substitutes and obesity was identified through PubMed and Google Scholar, utilizing the search terms "BPA substitutes", "bisphenol analogues", "BPS", "BPF", "BPAF", "obesity", "obesogens", "adipogenesis", "PPARγ", and "adipocyte differentiation". Various population-based studies were assessed to gain a better understanding of the epidemiology, which revealed evidence that BPA substitutes may act as obesogens at the pathophysiological level. Additional studies were assessed to explore the potential mechanisms by which these compounds act as obesogens. For BPS, these mechanisms include Peroxisome proliferator-activated receptor gamma (PPARγ) activation, potentiation of high-fat diet induced weight-gain, and stimulation of adipocyte hypertrophy and adipose depot composition. For BPF and BPAF, the evidence is more inconclusive. Given the current understanding of these compounds, there is sufficient concern about exposures. Thus, further research needs to be conducted on the relationship of BPA substitutes to obesity to inform on the potential public health measures that can be implemented to minimize exposures.

Peroxisome proliferator-activated receptor gamma (PPARγ) activation: a potential treatment for ascites syndrome in broiler chickens

Ascites (serous fluid accumulation in the abdominal cavity) has been observed worldwide in fast growing broilers. Pulmonary vascular remodeling is an important pathological feature of broiler ascites syndrome. Peroxisome proliferators-activated receptor gamma (PPARγ) and peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α) are expressed in pulmonary vascular endothelial cells and vascular smooth muscle cells (VSMC) where they participate in the regulation of normal pulmonary vascular function. The objective of the present study was to investigate the effects of omega-3 fatty acids (found in fish oil) and pioglitazone (PIO) as natural and synthetic PPARγ ligands supplementation on PPARγ and PGC-1α expression in the prevention of pulmonary arterial hypertension (PAH) syndrome in broiler chickens. The experiment was conducted with 4 treatment groups: 1) negative control, normal temperature conditions with basal diet; 2) positive control, low-temperature conditions with basal diet; 3) positive control+10 mg PIO/kg of weight/d and 4) positive control+1% FO. Each treatment had 5 replicates. Ascites heart index (RV/TV) was significantly (P < 0.05) reduced in chickens receiving FO (0.20) and PIO (0.21) compared to the positive control group (0.26). The addition of PIO in broilers under cold-induced ascites significantly increased the expression of PPARγ (9.44) and PGC-1α (5.81) genes in lung tissue compared to the negative control group (1.03, P < 0.05). Proliferative indexes of VSMC in pulmonary arteries such as PMT, PIT, and percentage wall thickness were significantly elevated in positive control group, indicating that pulmonary vascular remodeling occurred following VSMC proliferation in ascites. The vessel internal diameter was increased in FO and PIO groups. Based on these results, activation and expression of PPARγ and PGC-1α genes as a critical regulator of pulmonary artery smooth muscle cell using ligands, especially PIO, can be effective in reducing the incidence of PAH in broiler chickens.

PO-02-246 PPARΓ ACTIVATION MEDIATES CARDIAC PATHOLOGIES IN TWO MOUSE MODELS OF ARRHYTHMOGENIC CARDIOMYOPATHY (ACM) AND ITS THERAPEUTIC IMPLICATIONS

Using ACM patient-specific induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs), we showed that abnormal peroxisome proliferator-activated receptor-gamma (PPARγ) activation on normal adult PPARα-mediated metabolic backgrounds in CMs resulted in pathological hallmarks of ACM. PPARγ inhibitors rescue all ACM pathologies effects (Nature 2013) but may carry systemic side effects. Here, we study the pathogenic role of PPARγ activation in 2 ACM mouse models and test therapeutic potentials of 2 angiotensin II-receptor blockers (ARBs) commonly used to treat cardiomyopathies: Valsartan and Losartan. Valsartan has minimal activity yet Losartan has strong activity for PPARγ gene activation, respectively. We used 2 established ACM mouse models in this study: 1) mice with tamoxifen (TAM)-inducible and CM-specific (by αγMHC-Cre) double knockout (DKO) of plakoglobin (JUP) and βcatenin (MCB 2012) that developed ACM pathologies at 2-3 months only after TAM injection; and 2) mice with CM-specific and homozygous knockout of JUP (JUP KO, Hum Mol Genet 2011) that develop ACM pathologies rapidly in 1-2 months after birth. Feeding DKO mice with 0.1 mg/ml rosiglitazone (Rosi, a PPARγ activator) for 2 weeks (wks) after TAM injection accelerated the decrease in left ventricular ejection fraction (LV EF) (from 67.4% to 27.1%) within 2-3 weeks after feeding Rosi. For JUP KO mice at 8-9 wks after birth, the pathological hearts showed hyperactivated PPARγ (at both mRNA and protein levels) and elevated apoptotic gene expressions (3-fold increases in caspase 3 and BAX/BCL2 ratios). Feeding both ACM mouse models with 0.2 mg/ml Valsartan for 6 wks reduced PPARγ proteins and apoptotic genes (BAX/BCL2 ratios) by 2-3 folds. In JUP KO mice, Valsartan prevented LV EF deterioration yet losartan at equivalent doses led to early death and reduced LV EF. Our study results support strongly that abnormal PPARγ activation in ACM CMs plays a key pathogenic role in both human iPSC-CM-based and 2 mouse models of ACM. An ARB with PPARγ agnostic activities can worsen ACM pathologies and only ARB with minimal PPARγ agonistic activity can prevent ACM disease progression. These results have significant implications in avoiding using any drug with PPARγ agnostic activities to treat human ACM.

Oxylipin-PPARγ-initiated adipocyte senescence propagates secondary senescence in the bone marrow

The chronic use of glucocorticoids decreases bone mass and quality and increases bone-marrow adiposity, but the underlying mechanisms remain unclear. Here, we show that bone-marrow adipocyte (BMAd) lineage cells in adult mice undergo rapid cellular senescence upon glucocorticoid treatment. The senescent BMAds acquire a senescence-associated secretory phenotype, which spreads senescence in bone and bone marrow. Mechanistically, glucocorticoids increase the synthesis of oxylipins, such as 15d-PGJ2, for peroxisome proliferator-activated receptor gamma (PPARγ) activation. PPARγ stimulates the expression of key senescence genes and also promotes oxylipin synthesis in BMAds, forming a positive feedback loop. Transplanting senescent BMAds into the bone marrow of healthy mice is sufficient to induce the secondary spread of senescent cells and bone-loss phenotypes, whereas transplanting BMAds harboring a p16INK4a deletion did not show such effects. Thus, glucocorticoid treatment induces a lipid metabolic circuit that robustly triggers the senescence of BMAd lineage cells that, in turn, act as the mediators of glucocorticoid-induced bone deterioration.

PPAR-γ Activation Alleviates Osteoarthritis through Both the Nrf2/NLRP3 and PGC-1α/Δψ m Pathways by Inhibiting Pyroptosis.

Osteoarthritis (OA) is a common degenerative joint disease with a gradually increasing morbidity in the aging and obese population. Emerging evidence has implicated pyroptosis in the etiology of OA and it may be recognized as a therapeutic target in OA. We have previously reported regarding another disease that peroxisome proliferator-activated receptor gamma (PPAR-γ) activation exerts an anti-inflammatory effect by suppressing the nucleotide-binding and oligomerization domain-like receptor containing protein (NLRP) 3 inflammasome. However, the relationship between PPAR-γ and NLRP3-mediated pyroptosis in OA cartilage and its underlying mechanisms is fully unclear. In this study, we found that the level of NLRP3-mediated pyroptosis in severe lateral femoral condyle cartilage wear in the knee of an OA patient was significantly higher than that in the mild lateral femoral condyle cartilage wear areas. Moreover, in lipopolysaccharide (LPS)/adenosine triphosphate (ATP)-induced primary chondrocytes and knee OA rat models, we demonstrated that activation of PPAR-γ by pioglitazone (Piog) attenuated LPS/ATP-induced chondrocyte pyroptosis and arthritis. These effects were partially counteracted by either blocking the nuclear factor erythroid-2-related factor (Nrf2)/NLRP3 or PGC1-α/Δψ m signaling pathway. Simultaneous depression of these two signaling pathways can completely abrogate the protective effects of Piog on OA and chondrocytes. Taken together, Piog protects OA cartilage against pyroptosis-induced damage by simultaneously activating both the Nrf2/NLRP3 and PGC-1α/Δψ m pathways, which enhances antioxidative and anti-inflammatory responses as well as mitochondrial biogenesis. Therefore, Piog may be a promising agent for human OA cartilage damage in future clinical treatments.

The Cardioprotective Effect of Corosolic Acid in the Diabetic Rats: A Possible Mechanism of the PPAR-γ Pathway.

The study was conducted to determine whether corosolic acid could protect the myocardium of diabetic rats from damage caused by isoproterenol (ISO) and, if so, how peroxisome proliferator-activated receptor gamma (PPAR-γ) activation might contribute into this protection. Diabetes in the rats was induced by streptozotocin (STZ), and it was divided into four groups: the diabetic control group, diabetic rats treated with corosolic acid, diabetic rats treated with GW9662, and diabetic rats treated with corosolic acid plus GW9662. The study was carried out for 28 days. The diabetic control and ISO control groups showed a decrease in mean arterial pressure (MAP) and diastolic arterial pressure (DAP) and an increase in systolic arterial pressure (SAP). The rat myocardium was activated by corosolic acid treatment, which elevated PPAR-γ expression. A histopathological analysis showed a significant reduction in myocardial damage by reducing myonecrosis and edema. It was found that myocardial levels of CK-MB and LDH levels were significantly increased after treatment with corosolic acid. By decreasing lipid peroxidation and increasing endogenous antioxidant levels, corosolic acid therapy showed a significant improvement over the ISO diabetic group. In conclusion, our results prove that corosolic acid can ameliorate ISO-induced acute myocardial injury in rats. Based on these results, corosolic acid seems to be a viable new target for the treatment of cardiovascular diseases and other diseases of a similar nature.

Knockdown of SEMA7A alleviates MPP+ -induced apoptosis and inflammation in BV2 microglia via PPAR-γ activation and MAPK inactivation.

The inflammation mediated by microglial cells plays an important role in the process of neurodegenerative diseases. Recent evidence indicates that semaphorin 7A (SEMA7A) is implicated in various neurodegenerative diseases, but whether it plays a role in Parkinson's disease (PD)remains unclear. In this study, 1.0 mmol/L 1-methyl-4-phenylpyridinium (MPP+ )-stimulated mouse microglia (BV2)cells were used as an in vitro model of PD. The expression of SEMA7A was detected by quantitative polymerase chain reaction. Cell Counting Kit-8 and apoptosis kits were used to analyze the viability and apoptosis of BV-2 cells. The content of IL-6, IL-β, and tumor necrosis factor-α was determined by ELISA (enzyme-linked immunosorbent assay) kit. Western blot was used to detect the protein expression level of the inducible NO synthase and cyclooxygenase-2. Our findings indicated that SEMA7A expression in BV2 cells was upregulated after MPP+ stimulation. Knockdown of SEMA7A promoted cell viability while it inhibited apoptosis and the expression of proinflammatory enzymes and proinflammatory cytokines. Silencing SEMA7A-induced peroxisome proliferator-activated receptor-gamma (PPAR-γ) activation and mitogen-activated protein kinase (MAPK)signaling pathway inactivation. Furthermore, a PPAR-γ inhibitor and an MAPK activator promoted the effect of MPP+ on cell viability, apoptosis, and inflammation of BV2 cells; what is more, the PPAR-γinhibitor and MAPK activator blocked the inhibitory effect of SEMA7A downregulation on MPP+ -induced injury. In general, knockdown of SEMA7A inhibits MPP+ -induced BV2 cell apoptosis and inflammation via PPAR-γactivation and MAPK inactivation, which may provide a new therapy target for PD.