PPARγ Inhibitor Research Articles

Prenatal exposure to triphenyl phosphate activated PPARγ in placental trophoblasts and impaired pregnancy outcomes

The health risks of triphenyl phosphate (TPhP) have increased since its widespread application. Using placental trophoblast cell line JEG-3, we demonstrated that TPhP could induce endoplasmic reticulum stress (ERS) and cell apoptosis through PPARγ-mediated lipid metabolism. However, the developmental toxicity of TPhP through the placenta is not known. In this study, prenatal TPhP exposure to mice was investigated. Pregnant mice were orally exposed to TPhP (1 and 5 mg/kg) from embryonic day 0 (E0) until delivery. The results showed that TPhP could accumulate in placenta and impair pregnancy outcomes. After exposure, at E18, placental hormone chorionic gonadotrophin and testosterone levels were significantly decreased, but progesterone and estradiol levels were significantly increased, and placental angiogenesis was activated in the low-dose exposure group. While, in the high-dose exposure group, only estradiol levels were significantly increased. Different with the effect on hormone level or angiogenesis, TPhP significantly increased PPARγ and its regulated lipid transport proteins FABP, FATP, and CD36, and induced lipid accumulation in placental trophoblasts of both low- and high-exposure group. RNA-seq analysis of the placenta identified differentially expressed genes that were mainly involved in the ERS and MAPK signaling pathways. Western blot analysis verified that the protein levels related to ERS stress and apoptosis were significantly increased. To further confirm the role of PPARγ in TPhP mediated placental toxicity, pregnant mice were orally exposed to TPhP (1 mg/kg) or TPhP (1 mg/kg) + GW9662 (PPARγ inhibitor, 2 mg/kg) from E0 until delivery. The results showed that GW9662 could ameliorate the effect of TPhP on placental lipid accumulation, ERS and cell apoptosis, suggesting that PPARγ mediated the placental toxicity of TPhP. Overall, our results indicated that prenatal TPhP exposure impaired pregnancy outcomes, at least partly through PPARγ regulated function of trophoblast.

Anti-adipogenic effect of vitexin on human mesenchymal stem cells is mediated via inhibition of PPARγ and modulation of redox status

Anti-adipogenic effect of vitexin on human mesenchymal stem cells is mediated via inhibition of PPARγ and modulation of redox status

Esculentoside A alleviates cognitive deficits and amyloid pathology through peroxisome proliferator-activated receptor γ-dependent mechanism in an Alzheimer's disease model

BackgroundAlzheimer's disease (AD) is characterized clinically by cognitive deficits and pathologically by amyloid-β (Aβ) deposition and tau aggregation, as well as the brain atrophy. Esculentoside A (EsA), a neuroprotective saponin, is isolated from Phytolacca esculenta and shows potent health-promoting effects in a variety of experimental models. However, there are minimal reports on the effects of EsA on triple transgenic AD mice. PurposeThe current research aimed at investigating the protective effects and underlying mechanisms of EsA on the mitigation of cognitive deficits and pathology in triple transgenic AD mice. MethodsTriple transgenic AD mice (3 × Tg-AD) of 8 months old received intraperitoneal treatment of 5 or 10 mg/kg EsA for 8 consecutive weeks. Morris water maze test and open field test were made to evaluate the cognitive function and degree of anxiety of the mice. Liquid chromatography with tandem mass spectrometry analysis was performed to characterize and to quantify EsA in the blood and brain of mice. Immunofluorescence assay and Western blot were adopted to measure the levels of peroxisome proliferator-activated receptor gamma (PPARγ) and key proteins in Aβ pathology, ER stress- and apoptosis-associated pathways. The combination of EsA with PPARγ were theoretically calculated by molecular docking programs and experimentally confirmed by the bio-layer interferometry technology. ResultsSupplemental EsA could improve the cognitive deficits of 3 × Tg-AD mice. EsA penetrated the brain-blood barrier to exert a strong effect on AD mice, evidenced as decreasing Aβ generation, reducing the degrees of oxidative and ER stress, and mitigating neuronal apoptosis through the increase of PPARγ expression. In the culture of primary neurons, addition of PPARγ inhibitor GW9662 eliminated the effects of EsA on AD pathologies. Direct combination of EsA with PPARγ were demonstrated by molecular docking programs and bio-layer interferometry technology. ConclusionsFor the first time, these outcomes revealed that EsA could penetrate the brain-blood barrier to exert a strong effect on ameliorating cognitive deficits in 3 × Tg-AD mice and exert neuroprotective effects toward AD pathology via PPARγ-dependent mechanism.

Inhibition of DNA methylation de‐represses peroxisome proliferator‐activated receptor‐γ and attenuates pulmonary fibrosis

Development of pulmonary fibrosis is associated with altered DNA methylation modifications of fibrogenic gene expression. However, their causal relationships and the underlying mechanisms remain unclear. This study investigates the critical role of DNA methylation aberration-associated suppression of peroxisome proliferator-activated receptor-γ (PPARγ) in pulmonary fibrosis. Expression of PPARγ and bioactive DNA methyltransferases (DNMTs) and PPARγ promoter methylation status were examined in fibrotic lungs of idiopathic pulmonary fibrosis (IPF) patients and bleomycin (Blm)-treated mice. DNA demethylating agent 5-aza-2'-deoxycytidine (5aza) and glycyrrhizic acid (GA) derived from medicinal plant were assessed for their PPARγ de-repression and anti-pulmonary fibrosis activities. PPARγ knockout mice were created to determine the critical role of PPARγ in this protection. Lung PPARγ expression was markedly suppressed in IPF patients and Blm mice, accompanied by increased DNMT 1/DNMT3a and PPARγ promoter hypermethylation. Administration of 5-aza and GA similarly demethylated PPARγ promoter, restored PPARγ loss and alleviated fibrotic lung pathologies, including structural alterations and adverse expression of fibrotic mediators and inflammatory cytokines. In cultured lung fibroblasts and alveolar epithelial cells, GA alleviated PPARγ-mediated suppression of fibrosis in a gain of DNMT-sensitive manner, and in PPARγ knockout mice, the anti-fibrotic effects of 5aza and GA were significantly reduced, suggesting that PPARγ is a critical mediator of epigenetic pulmonary fibrogenesis. Aberrant DNMT1/3a elevations and the resultant PPARγ suppression contribute significantly to the development of pulmonary fibrosis, and strategies targeting DNMT/PPARγ axis with synthetic or natural compounds might benefit patients with pulmonary fibrotic disorders.

Protective mechanisms of telmisartan against hepatic ischemia/reperfusion injury in rats may involve PPARγ-induced TLR4/NF-κB suppression.

Hepatic ischemia-reperfusion (I/R) is an important cause of liver damage in many clinical situations. Toll-like receptor 4 (TLR4)/nuclear factor-kappa B (NF-κB) is an inflammatory pathway activated in hepatic I/R injury. Telmisartan, a selective angiotensin II type 1 receptor antagonist and peroxisome proliferator-activated receptor-gamma (PPARγ) partial agonist, can inhibit the expression of pro-inflammatory cytokines. The present work investigated the possible protective effect of telmisartan against hepatic I/R injury and explored its possible mechanisms in rats. Rats were divided into four equal groups: sham-operated control, telmisartan-treated sham-operated control, I/R untreated, and I/R telmisartan-treated groups. Hepatic injury was evaluated biochemically by serum activity of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) and histopathological examination. Hepatic oxidative stress biomarkers, myeloperoxidase level, PPARγ and TLR4 mRNA expression, and NF-κB and active caspase 3 immunoexpression were determined. The study showed that telmisartan attenuated hepatic I/R, as evidenced by decreased serum ALT and AST activities and confirmed by improvement of the histopathological changes. The protective effect of telmisartan was associated with modulation of oxidative stress parameters, myeloperoxidase level, PPARγ and TLR4 mRNA expression, and NF-κB and caspase 3 immunoexpression. Taken together, the current study showed that telmisartan could protect the rat liver from I/R injury. This hepatoprotective effect was attributed to, at least in part, increase in PPARγ expression and suppression of TLR4/NF-κB pathway.

Didymin Alleviates Cerebral Ischemia-Reperfusion Injury by Activating the PPAR Signaling Pathway.

PurposeCerebral ischemia-reperfusion (IR) injury is a severe secondary injury induced by reperfusion after stroke. Didymin has been reported to have a protective effect on intracerebral hemorrhage. However, the underlying mechanism of didymin on regulating cerebral IR injury remains largely unknown.Materials and MethodsA rat cerebral IR model and oxygen-glucose deprivation/reperfusion (OGD/R) model in PC12 cells were established. Hematoxylin and eosin (H&E) was used to detect the pathological changes in brain tissues, and TUNEL staining was performed to detect apoptosis of brain tissues. MTT and flow cytometry were used to measure the viability and apoptosis of PC12 cells. QRT-PCR and western blot were used to detect inflammation cytokines in PC12 cells. Western blot was used to measure the expression of PPAR-γ, RXRA, Bax, c-caspase-3, and Bcl-2.ResultsDidymin pretreatment decreased apoptotic rates, reduced levels of Bax and c-caspase-3, and increased Bcl-2 level in vivo and in vitro. Additionally, didymin pretreatment increased viability and decreased the inflammation levels [interleukin (IL)-1β, IL-6, tumor necrosis factor (TNF)-α, and monocyte chemotactic protein (MCP)-1] of OGD/R treated PC12 cells. Moreover, didymin activated the peroxisome proliferator-activated receptors (PPAR) signaling pathway and increased the expression of PPAR-γ and RXRA in OGD/R treated PC12 cells. Inhibition of PPAR-γ eliminated the protective effect of didymin on OGD/R treated cells.ConclusionDidymin protected neuron cells against IR injury in vitro and in vivo by activation of the PPAR pathway. Didymin may be a candidate drug for IR treatment.

The Study of Yin-Chen-Hao-Tang Preventing and Treating Alcoholic Fatty Liver Disease through PPAR Signaling Pathway Based on Network Pharmacology and RNA-Seq Transcriptomics.

Background Alcoholic fatty liver disease (AFLD) is the first stage of the alcoholic liver disease course. Yin-Chen-Hao-Tang (YCHT) has a good clinical effect on the treatment of AFLD, but its molecular mechanism has not been elucidated. In this study, we tried to explore the molecular mechanism of YCHT in improving hepatocyte steatosis in AFLD mice through network pharmacology and RNA sequencing (RNA-Seq) transcriptomics. Methods Network pharmacological methods were used to analyze the potential therapeutic signaling pathways and targets of YCHT on AFLD. Then, the AFLD mice model was induced and YCHT was administered concurrently. Liver injury was measured by serum alanine aminotransferase (ALT) activity and liver tissue H&E staining, and liver steatosis was determined by serum triglyceride (TG) level and liver tissue Oil Red staining. The molecular mechanism of YCHT on prevention and treatment of mice AFLD was investigated according to the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis of the differential expression genes data obtained by liver tissue RNA-Seq. Finally, ethanol-induced AFLD AML12 hepatocyte model was established, YCHT with or without PPARα agonist pemafibrate or PPARγ inhibitor GW9662 was administered, Nile Red fluorescent staining was used to evaluate steatosis levels in AML12 hepatocytes, and qRT-PCR was used to detect PPARα and PPARγ gene expression. Results The results of network pharmacology analysis showed that YCHT may exert its pharmacological effect on AFLD through 312 potential targets which are involved in many signaling pathways including the PPAR signaling pathway. AFLD mice experiments results showed that YCHT markedly decreased mice serum ALT activity and serum TG levels. YCHT also significantly improved alcohol-induced hepatic injury and steatosis in mice livers. Furthermore, KEGG pathway enrichment results of RNA-Seq showed that the PPAR signaling pathway should be the most relevant pathway of YCHT in the prevention and treatment of AFLD. AFLD hepatocyte model experiment results showed that YCHT could remarkably reduce hepatocyte steatosis through reducing PPARγ expression and increasing PPARα expression. Conclusions Our study discovered that PPARγ and PPARα are the key targets and the PPAR signaling pathway is the main signaling pathway for YCHT to prevent and treat AFLD.

A flavone derivative from Andrographis echioides leaf extract positively alters the molecular targets of insulin signaling pathway

Insulin resistance and obesity go hand-in-hand while considering the pathophysiology of type 2 diabetes. The mechanism of obesity-related insulin resistance includes a series of molecular markers such as insulin receptor substrate, protein kinase, glucose transporter, etc., that act as primary targets for various antidiabetic drugs. However, the undesired side effects of these drugs have steered research toward safer and more effective alternatives. This study involves the bioactivity-guided isolation of phytocompounds from Andrographis echioides and studying its effect on the above-mentioned molecular markers. The bioactive compounds were first isolated by column chromatography and tested for their α-amylase inhibition potential. The compound with better inhibition ability was then characterized using FTIR, MS, 1H, and 13C NMR techniques. Then, the compound was evaluated for its glucose uptake enhancing ability and cytotoxicity against 3T3 L1 and L6 cell lines. Furthermore, the mechanism of action of the compound was studied on molecular targets such as PPARγ, IRS, IRβ, GLUT4, and Tyr-PI3K. As a result, 5-hydroxy- 2-(4‑methoxy-3-((E)-3-methylbut-1-enyl)-5-(3- methylbut-3-enyl)phenyl)chroman-4-one, was isolated and found to be a significant inhibitor of α-amylase enzyme (IC50 value of 14.52 µg/ml) and PPARγ (IC50 value of 3.357 µg/ml). In addition, it was a strong enhancer of glucose uptake in both 3T3 L1 (48.82 ±2.74%) and L6 (63.83 ± 1.54%) cell lines. The mechanism of action was altering the insulin-signaling pathway by upregulating the molecular proteins involved in the etiology of type 2 diabetes. In conclusion, the compound isolated from the leaves of Andrographis echioides possesses a significant regulatory effect on glucose uptake and other markers of the insulin-signaling pathway.

PPARγ Regulates Triclosan Induced Placental Dysfunction.

Exposure to the antibacterial agent triclosan (TCS) is associated with abnormal placenta growth and fetal development during pregnancy. Peroxisome proliferator-activated receptor γ (PPARγ) is crucial in placenta development. However, the mechanism of PPARγ in placenta injury induced by TCS remains unknown. Herein, we demonstrated that PPARγ worked as a protector against TCS-induced toxicity. TCS inhibited cell viability, migration, and angiogenesis dose-dependently in HTR-8/SVneo and JEG-3 cells. Furthermore, TCS downregulated expression of PPARγ and its downstream viability, migration, angiogenesis-related genes HMOX1, ANGPTL4, VEGFA, MMP-2, MMP-9, and upregulated inflammatory genes p65, IL-6, IL-1β, and TNF-α in vitro and in vivo. Further investigation showed that overexpression or activation (rosiglitazone) alleviated cell viability, migration, angiogenesis inhibition, and inflammatory response caused by TCS, while knockdown or inhibition (GW9662) of PPARγ had the opposite effect. Moreover, TCS caused placenta dysfunction characterized by the significant decrease in weight and size of the placenta and fetus, while PPARγ agonist rosiglitazone alleviated this damage in mice. Taken together, our results illustrated that TCS-induced placenta dysfunction, which was mediated by the PPARγ pathway. Our findings reveal that activation of PPARγ might be a promising strategy against the adverse effects of TCS exposure on the placenta and fetus.

Inhibition of PPARγ Gene Particle Downregulates the Differentiation of Rabbit Bone Marrow Mesenchymal Stem Cells into Adipocytes

This study aims to evaluate the effect of peroxisome proliferator-activated receptor (PPAR) γ gene inhibition on the adipogenic differentiation of rabbit bone marrow mesenchymal stem cells (BMSCs). Primary BMSCs were isolated from rabbit bone marrow, cultured, and the markers of BMSCs on cell’s surface were analyzed using flow cytometry. The experiment involved five groups, namely, control: untreated BMSCs; model: BMSCs treated with ethanol; empty siRNA: BMSCs treated with ethanol + empty siRNA; PPARγ: BMSCs treated with ethanol + PPARγ siRNA; and PPARγ inhibitor: BMSCs treated with ethanol + T0070907. RT-PCR and Western blotting were used to detect changes in the expression level of PPARγ, PETALA2 (AP2), lipoprotein lipase (LPL), fatty acid transport protein (FATP) 1, and fatty acid transporter (FAT). Adipocyte count and triacylglycerol content of the model and the empty siRNA groups were considerably greater than the control group ( P < 0.01 ). After the inhibition with PPARγ or T0070907, adipocyte count and triacylglycerol content of the PPARγ and T0070907 groups were significantly reduced ( P < 0.01 ), with no statistically significantly difference than the control group ( P > 0.05 ). The expression levels of PPARγ gene and protein in the model and empty siRNA groups were ominously enhanced than the control group ( P < 0.01 ), and after inhibition with PPARγ or T0070907, the PPARγ gene or protein expression level of PPARγ and T0070907 groups significantly reduced ( P < 0.01 ), with no statistically significance difference compared to the control group ( P > 0.05 ). The expression levels of Ap2, LPL, FATP1, and FAT genes in the model and empty siRNA groups were considerably greater compared to the control group ( P < 0.01 ). Inhibition with PPARγ or T0070907 in the PPARγ and T0070907 groups, respectively, lead to significantly reduced expression levels of adipogenic genes ( P < 0.01 ), with no statistically significance difference compared to the control ( P > 0.05 ). Inhibition of PPARγ gene downregulates the differentiation of BMSCs into adipocytes, indicating its putative role in the expression of adipogenic genes.

Empagliflozin Ameliorates Free Fatty Acid Induced-Lipotoxicity in Renal Proximal Tubular Cells via the PPARγ/CD36 Pathway in Obese Mice.

High serum levels of free fatty acids (FFAs) could contribute to obesity-induced nephropathy. CD36, a class B scavenger receptor, is a major receptor mediating FFA uptake in renal proximal tubular cells. Empagliflozin, a new anti-diabetic agent, is a specific inhibitor of sodium-glucose co-transporter 2 channels presented on renal proximal tubular cells and inhibits glucose reabsorption. In addition, empagliflozin has shown renoprotective effects. However, the mechanism through which empagliflozin regulates CD36 expression and attenuates FFA-induced lipotoxicity remains unclear. Herein, we aimed to elucidate the crosstalk between empagliflozin and CD36 in FFA-induced renal injury. C57BL/6 mice fed a high-fat diet (HFD) and palmitic acid-treated HK-2 renal tubular cells were used for in vivo and in vitro assessments. Empagliflozin attenuated HFD-induced body weight gain, insulin resistance, and inflammation in mice. In HFD-fed mice, CD36 was upregulated in the tubular area of the kidney, whereas empagliflozin attenuated CD36 expression. Furthermore, empagliflozin downregulated the expression of peroxisome proliferator-activated receptor (PPAR)-γ. Treatment with a PPARγ inhibitor (GW9662) did not further decrease PPARγ expression, whereas a PPARγ antagonist reversed this effect; this suggested that empagliflozin may, at least partly, decrease CD36 by modulating PPARγ. In conclusion, empagliflozin can ameliorate FFA-induced renal tubular injury via the PPARγ/CD36 pathway.

Lycium barbarum polysaccharides alleviate LPS-induced inflammatory responses through PPARγ/MAPK/NF-κB pathway in bovine mammary epithelial cells.

Current research examined Lycium barbarum polysaccharides (LBP) for combating LPS-induced inflammatory responses in primary bovine mammary epithelial cells. We uncovered a preventive role of LBP in reducing detrimental effects induced by LPS including inhibition of NF-κB and MAPK along with peroxisome proliferator-activated receptor-γ (PPARγ) activation. The decrease in cell proliferation due to LPS was curtailed by pretreatment with LBP. Moreover, the effect of LBP on regulation of inflammatory responses in bovine mammary epithelial cell was PPARγ dependent. Collectively, data suggest that LBP reverses LPS-induced inflammatory response via MAPK/NF-κB signaling in a PPARγ-activation-dependent manner. Thus, the study provides new insights into therapeutic strategies for combating mastitis using LBP and highlighted the link between PPARγ and regulation of mammary cell inflammation.

Abstract 14460: Mitochondrial Dysfunction is Involved in Diabetic Cardiomyopathy

Introduction: Diabetes is a strong risk factor not only for cardiovascular disease (CVD) but also for the development of chronic kidney disease (CKD) and represents a large and threatening public health challenge. We previously reported the deficiency of heat shock proteins and translocase of inner mitochondrial membrane (TIM) proteins are involved in the pathogenesis of hypertensive and uremic cardiomyopathy. Hypothesis: In this study, we further study the mechanism of mitochondrial dysfunction in the development of CVD and diabetic cardiomyopathy in CKD. Methods: Commercially available primary human atrial and ventricular cardiac myofibroblast and primary human aortic endothelial cells from 3 different age-matched sources were used in our type 2 diabetic cell model, in vitro. Immunohistochemistry, western blotting, Next-Generation RNA Sequencing, and real-time polymerase chain reaction (qPCR) were used in our proposed study. Results: Our data show that ATP5F1E (ATP Synthase F1 Subunit Epsilon), and cAMP regulator, Phosphodiesterase 8B are significantly (P<0.01) preserved in the normal cardiac myofibroblast and aortic endothelial cell. In addition, gene expression of the key ATP synthesis: OPA1, MFN1, TIM, and inflammation marker: MSR1, WNT5 were also significantly (p<0.05) increased in the non-diabetic cardiac myofibroblast and aortic endothelial cell. We next showed that key PPAR pathway regulators, Perilipin 1 (PLIN1) and PPARγ were significantly (p<0.05) increased in our in vitro diabetic cell model. Furthermore, PPARγ inhibitor, FABP4 (fatty acid binding protein-4) which functions as an atherosclerosis promoter was significantly up-regulated in (p<0.05) the non-diabetic cardiac myofibroblast and aortic endothelial cell. Conclusions: Mitochondrial ATP production is the main energy source for intracellular metabolic pathways and our study shows that mitochondrial dysfunction and down-regulation of ATP production may inhibit the hydrolysis of the second messenger cAMP that promotes the development of CVD and diabetic cardiomyopathy in CKD.

Docosahexaenoic acid reduces hypoglycemia-induced neuronal necroptosis via the peroxisome proliferator-activated receptor γ/nuclear factor-κB pathway

DHA has been shown to be neuroprotective and important to neurogenesis, but its role in HG-induced brain injury and the underlying mechanisms remain unknown. To elucidate the therapeutic effect of DHA, we established a mouse model with insulin-induced hypoglycemic brain injury and an in vitro model of HT-22 cells using a sugar-free medium. DHA treatment significantly reduced neuronal death and improved HG-induced learning and memory deficits. Moreover, DHA inhibited neuronal necroptosis and decreased the concentrations of TNF-α, IL-1β and TNFR1. DHA also activated PPAR-γ and suppressed the NF-κB pathway in mouse brain tissues. In vitro, DHA treatment restored the viability and decreased necroptosis of HT-22 cells treated with glucose deprivation. However, the inhibition of PPAR-γ with T0070907 reversed neuroprotective and anti-necroptosis effects of DHA in HG-induced brain injury, which is associated with the activation of the downstream NF-κB pathway. We conclude that DHA displays a protective effect against HG-induced brain injury through the PPAR-γ/NF-κB pathway and represents a promising method to prevent HG-induced brain injury.

PPARα/γ signaling pathways are involved in Chlamydia pneumoniae-induced foam cell formation via upregulation of SR-A1 and ACAT1 and downregulation of ABCA1/G1

Chlamydia pneumoniae (Cpn) has been reported to be involved in the pathogenesis of early atherosclerosis by inducing macrophage-derived foam cell formation in the presence of low-density lipoprotein (LDL). However, the biochemical mechanisms underlying Cpn-induced foam cell formation are still not fully elucidated. The present study showed that in LDL-treated THP-1-derived macrophages, Cpn not only upregulated the expression of scavenger receptor A1 (SR-A1) and acyl-coenzyme A: cholesterol acyltransferase 1 (ACAT1), but it also downregulated the expression of ATP binding cassette transporters (ABCA1 and ABCG1) at both the mRNA and protein levels. These processes facilitated cholesterol accumulation and promoted macrophage-derived foam cell formation. Treatment with the peroxisome proliferator-activated receptor (PPAR)-γ agonist rosiglitazone or the PPARα agonist fenofibrate decreased the number of foam cells induced by Cpn, while the PPARγ antagonist GW9662, the PPARα antagonist MK886, or PPARα/γ siRNAs enhanced the effect of Cpn on foam cell formation and gene expression of SR-A1, ACAT1, and ABCA1/G1. Moreover, the PPARγ agonist rosiglitazone reversed the downregulation of CD36 by Cpn, while PPARγ siRNA and the PPARγ inhibitor GW9662 further suppressed CD36 expression. However, the PPARα agonist, inhibitor, and siRNA all showed no effect on CD36 expression. In conclusion, the PPARα and PPARγ pathways are both involved in Cpn-induced macrophage-derived foam cell formation by upregulating SR-A1 and ACAT1 and downregulating ABCA1/G1 expression.

Alternatives for the worse: Molecular insights into adverse effects of bisphenol a and substitutes during human adipocyte differentiation.

Bisphenol A (BPA), which is used in a variety of consumer-related plastic products, was reported to cause adverse effects, including disruption of adipocyte differentiation, interference with obesity mechanisms, and impairment of insulin- and glucose homeostasis. Substitute compounds are increasingly emerging but are not sufficiently investigated.We aimed to investigate the mode of action of BPA and four of its substitutes during the differentiation of human preadipocytes to adipocytes and their molecular interaction with peroxisome proliferator-activated receptor γ (PPARγ), a pivotal regulator of adipogenesis.Binding and effective biological activation of PPARγ were investigated by surface plasmon resonance and reporter gene assay, respectively. Human preadipocytes were continuously exposed to BPA, BPS, BPB, BPF, BPAF, and the PPARγ-antagonist GW9662. After 12days of differentiation, lipid production was quantified via Oil Red O staining, and global protein profiles were assessed using LC-MS/MS-based proteomics. All tested bisphenols bound to human PPARγ with similar efficacy as the natural ligand 15d-PGJ2in vitroand provoked an antagonistic effect on PPARγ in the reporter gene assay at non-cytotoxic concentrations. During the differentiation of human preadipocytes, all bisphenols decreased lipid production. Global proteomics displayed a down-regulation of adipogenesis and metabolic pathways, similar to GW9662. Interestingly, pro-inflammatory pathways were up-regulated, MCP1 release was increased, and adiponectin decreased. pAKT/AKT ratios revealed significantly reduced insulin sensitivity by BPA, BPB, and BPS upon insulin stimulation.Thus, our results show that not only BPA but also its substitutes disrupt crucial metabolic functions and insulin signaling in adipocytes under low, environmentally relevant concentrations. This effect, mediated through inhibition of PPARγ, may promote hypertrophy of adipose tissue and increase the risk of developing metabolic syndrome, including insulin resistance.

Moracin D induces apoptosis in prostate cancer cells via activation of PPAR gamma/PKC delta and inhibition of PKC alpha.

Herein, apoptotic mechanism of Moracin D was explored in prostate cancer cells in association with peroxisome proliferator-activated receptor gamma (PPAR-γ)-related signaling involved in lipid metabolism. Moracin D augmented cytotoxicity and sub G1 population in PC3 and DU145 prostate cancer cells, while DU145 cells were more susceptible to Moracin D than PC3 cells. Moracin D attenuated the expression of caspase-3, poly (ADP-ribose) polymerase (PARP), B-cell lymphoma 2 (Bcl-2), and B-cell lymphoma-extra-large (Bcl-xL) in DU145 cells. Consistently, Moracin D significantly augmented the number of terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL)-positive cells in DU145 cells. Interestingly, Moracin D activated PPAR-γ and phospho-protein kinase C delta (p-PKC-δ) and inhibited phospho-protein kinase C alpha (p-PKC-α) in DU145 cells. Furthermore, STRING bioinformatic analysis reveals that PPAR-γ interacts with nuclear factor-κB (NF-κB) that binds to PKC-α/PKC-δ or protein kinase B (AKT) or extracellular signal-regulated kinase (ERK). Indeed, Moracin D decreased phosphorylation of NF-κB, ERK, and AKT in DU145 cells. Conversely, PPAR-γ inhibitor GW9662 reduced the apoptotic ability of Moracin D to activate caspase 3 and PARP in DU145 cells. Taken together, these findings provide a novel insight that activation of PPAR-γ/p-PKC-δ and inhibition of p-PKC-α are critically involved in Moracin D-induced apoptosis in DU145 prostate cancer cells.

FNDC5 induces M2 macrophage polarization and promotes hepatocellular carcinoma cell growth by affecting the PPARγ/NF-κB/NLRP3 pathway

PurposeThe purpose of this study was to investigate the effect of FNDC5 expression levels in hepatocellular carcinoma on the phenotypic changes of macrophages in tumor tissues. MethodsIn this study, we established an in vitro co-culture system of hepatocellular carcinoma cells and macrophages. Then we performed overexpression or knockdown of FNDC5 gene in hepatocellular carcinoma cells to observe the effect of changes in FNDC5 expression level on the phenotypic changes of THP-1 macrophages. And the conclusions obtained in the in vitro assay were further validated by a subcutaneous tumorigenic nude mice model. ResultsOur findings suggest that elevated FNDC5 expression in hepatocellular carcinoma cells lead to an increased M2 phenotype and decreased M1 phenotype in macrophages. This effect may be achieved by elevating PPARγ levels in macrophages while decreasing NF-κB and NLRP3 levels. These changes could be reversed by using PPARγ inhibitors. ConclusionWe preliminarily demonstrated that FNDC5 in hepatocellular carcinoma cells promotes the polarization of M2 macrophages by affecting the PPARγ/NF-κB/NLRP3 pathway.

Modulatory effect of euxanthone in liver cancer-bearing obese mice: crosstalk between PPARγ and TIMP3 signalling axes.

Liver cancer is one of the prominent cancer-associated fatal diseases with > 80% of cases befall in low-middle resource nations worldwide. In the current study, we studied the effect of euxanthone (EUX) on obesity-associated liver cancer using a high-fat diet-fed mouse model of diethylnitrosamine (DEN)-provoked hepatocellular carcinoma. Mice with 2weeks of age were intraperitoneally injected with diethylnitrosamine (DEN) 25mg/kg b.w. After 4weeks, the mice were divided into four groups with low-fat diet (LFD), high-fat diet (HFD), and EUX treatment groups with or without PPARγ inhibitor (GW9662). We observed that TIMP3, E-cadherin, and Klotho expressions were downmodulated, while MMP9, ADAM17, and Wnt signalling biofactors (Wnt5a, Wnt3a and β-catenin) were upmodulated in the HFD groups. Nevertheless, these aberrations were reciprocated by the treatment with EUX; at the same time, co-administration of PPARγ inhibitor ablated the anti-cancer effects of EUX, indicating that PPARγ activation is a pivotal mechanism underpinning the negative regulation of oncogenic factors by EUX. Together, these results imply that EUX might be a viable therapeutic option in the treatment of obesity-associated hepatocarcinogenesis.

FABP4 knockdown suppresses inflammation, apoptosis and extracellular matrix degradation in IL-1β-induced chondrocytes by activating PPARγ to regulate the NF-κB signaling pathway.

Osteoarthritis (OA) is a common degenerative disease that can lead to severe joint pain and loss of function, seriously threatening the health and normal life of patients. At present, the pathogenesis of OA remains to be clarified. Recent studies have shown that fatty acid-binding protein 4 (FABP4) is increased in the plasma and synovial fluid of patients with OA. However, the effect of FABP4 on OA is unclear. The present study established IL-1β-induced ATDC5 cells with FABP4 knockdown. Next, cell viability was detected with Cell Counting Kit-8 assay. The content of inflammatory factors, prostaglandin E2 and glycosaminoglycan (GAG) was detected via ELISA. The levels of reactive oxygen species (ROS) and superoxide dismutase (SOD) in cells were detected by using ROS and SOD kits, respectively. TUNEL staining was used to detect the apoptosis level. Western blotting was used to detect the expression levels of proteins. The results revealed that FABP4 was upregulated in IL-1β-induced ATDC5 cells. Knockdown of FABP4 increased cell viability, reduced inflammatory damage, oxidative stress and apoptosis in IL-1β-induced ATDC5 cells. Following FABP4 knockdown, the expression of matrix metalloproteinases (MMP3, MMP9 and MMP13) of IL-1β-induced ATDC5 cells was reduced, and the expression of GAG was promoted. FABP4 knockdown also inhibited the expression of NF-κB p65 and enhanced peroxisome proliferator-activated receptor (PPAR)γ expression. However, the presence of PPARγ inhibitor blocked the aforementioned effects of FABP4 on IL-1β-induced ATDC5 cells. In conclusion, FABP4 knockdown suppressed the inflammation, oxidative stress, apoptosis and extracellular matrix degradation of IL-1β-induced chondrocytes by activating PPARγ to inhibit the NF-κB signaling pathway.