Endotoxin downregulates peroxisome proliferator-activated receptor-γ via the increase in TNF-α release

2008 ◽  
Vol 294 (1) ◽  
pp. R84-R92 ◽  
Author(s):  
Mian Zhou ◽  
Rongqian Wu ◽  
Weifeng Dong ◽  
Asha Jacob ◽  
Ping Wang
Keyword(s):  
Gene Expression ◽  
Neutralizing Antibodies ◽  
Cecal Ligation ◽  
Polymyxin B ◽  
Peroxisome Proliferator ◽  
Peroxisome Proliferator Activated Receptor ◽  
Protein Levels ◽  
Ppar Γ ◽  
Tnf Α ◽  
A Cell

The nuclear receptor peroxisome proliferator-activated receptor-γ (PPAR-γ) is anti-inflammatory in a cell-based system and in animal models of endotoxemia. We have shown that PPAR-γ gene expression is downregulated in macrophages after lipopolysaccharide (LPS) stimulation. However, it remains unknown whether hepatic PPAR-γ is altered in sepsis and, if so, whether LPS directly downregulates PPAR-γ. To study this, rats were subjected to sepsis by cecal ligation and puncture (CLP). Hepatic tissues were harvested at 5, 10, and 20 h after CLP. PPAR-γ gene expression and protein levels were determined by RT-PCR and Western blot analysis, respectively. The results showed that PPAR-γ gene expression decreased at 10 and 20 h and that its proteins levels were reduced at 20 h after CLP. PPAR-γ levels were also decreased in animals that were administered LPS. To determine the direct effects of LPS on PPAR-γ downregulation, LPS binding agent polymyxin B (PMB) was administered intramuscularly after CLP. The administration of PMB significantly reduced plasma levels of endotoxin, but it did not prevent the downregulation of PPAR-γ expression. We found that circulating levels of TNF-α still remained significantly elevated in PMB-treated septic animals. We, therefore, hypothesize that the decrease of PPAR-γ expression is TNF-α dependent. To investigate this, Kupffer cells (KCs) were isolated from normal rats and stimulated with LPS or TNF-α. TNF-α significantly attenuated PPAR-γ gene expression in KCs. Although LPS decreased PPAR-γ in KCs, the downregulatory effect of LPS was blocked by the addition of TNF-α-neutralizing antibodies. Furthermore, the administration of TNF-α-neutralizing antibodies to animals before the onset of sepsis prevented the downregulation of PPAR-γ in sepsis. We, therefore, conclude that LPS downregulates PPAR-γ expression during sepsis via an increase in TNF-α release.

Cardiac peroxisome-proliferator-activated receptor expression in hypertension co-existing with diabetes

2011 ◽  
Vol 121 (7) ◽  
pp. 305-312 ◽  
Author(s):  
Ting-I Lee ◽  
Yu-Hsun Kao ◽  
Yao-Chang Chen ◽  
Nan-Hung Pan ◽  
Yung-Kuo Lin ◽  
...  
Keyword(s):  
Nadph Oxidase ◽  
Heart Function ◽  
Receptor Expression ◽  
Peroxisome Proliferator ◽  
Peroxisome Proliferator Activated Receptor ◽  
Spontaneously Hypertensive ◽  
Protein Levels ◽  
Ppar Γ ◽  
Tnf Α ◽  
Wistar Kyoto

Hypertension and DM (diabetes mellitus) are common chronic disorders that often co-exist. DM and PPAR (peroxisome-proliferator-activated receptor)-γ agonists may directly impair heart function. However, the effects of DM and PPAR-γ agonists on hypertensive myocardium are not known. Hence the aim of the present study was to investigate whether DM and a PPAR-γ agonist [RGZ (rosiglitazone)] modulated the effects of hypertension on myocardial expression of PPAR isoforms. Cardiac PPAR isoforms, TNF (tumour necrosis factor)-α and IL (interleukin)-6 were evaluated by real-time PCR and Western blotting in SHRs (spontaneously hypertensive rats), diabetic SHRs, diabetic SHRs treated with RGZ (5 mg/kg of body weight) and control WKY (Wistar–Kyoto) rats. Cardiac NADPH oxidase activity was quantified using a SOD (superoxide dismutase)-sensitive cytochrome c reduction assay. When compared with hearts from control WKY rats, hearts from SHRs had decreased PPAR-α and PPAR-δ mRNA and protein levels (39 and 44% respectively for PPAR-α, and 37 and 42% respectively for PPAR-δ), but had increased PPAR-γ mRNA and protein levels (1.9- and 1.4-fold respectively). The hypertension-induced changes in mRNA and protein of cardiac PPAR isoforms were enhanced in diabetic SHRs, which were attenuated in diabetic SHRs treated with RGZ. Cardiac TNF-α and IL-6 protein levels and NADPH oxidase activities were increased in SHRs and were increased further in diabetic SHRs. RGZ treatment decreased TNF-α and IL-6 protein levels and NADPH oxidase activities in hearts from diabetic SHRs. In conclusion, these findings suggest that DM and the PPAR-γ agonist modulated the hypertensive effects on cardiac PPAR isoform expression.

Gabapentin Reduces Alcohol Intake in Rats by Regulating NF-κB Signaling Pathway Via PPAR γ

2021 ◽  
Author(s):  
Jing Li ◽  
Kewei Xu ◽  
Hao Ding ◽  
Qiaozhen Xi
Keyword(s):  
Locomotor Activity ◽  
Signaling Pathway ◽  
Specific Inhibitor ◽  
Underlying Mechanism ◽  
Ethanol Consumption ◽  
Diglycidyl Ether ◽  
Peroxisome Proliferator ◽  
Peroxisome Proliferator Activated Receptor ◽  
Ppar Γ ◽  
Tnf Α

Abstract Aims Increasing preclinical and clinical reports have demonstrated the efficacy of gabapentin (GBP) in treating alcohol use disorder (AUD). However, the mechanism of the effects of GBP in AUD is largely unknown. Herein, we sought to investigate the effect of GBP in a rat model of AUD and explore the underlying mechanism. Methods The intermittent access to 20% ethanol in a 2-bottle choice (IA2BC) procedure was exploited to induce high voluntary ethanol consumption in rats. The rats were treated daily for 20 days with different doses of GBP, simultaneously recording ethanol/water intake. The locomotor activity and grooming behavior of rats were also tested to evaluate the potential effects of GBP on confounding motor in rats. The levels of IL-1β and TNF-α in serum and hippocampus homogenate from the rats were detected by using ELISA. The expressions of peroxisome proliferator-activated-receptor γ (PPAR-γ) and nuclear factor-κB (NF-κB) in the hippocampus were determined by immunofluorescence and western blot. Results GBP reduced alcohol consumption, whereas increased water consumption and locomotor activity of rats. GBP was also able to decrease the levels of IL-1β and TNF-α in both serum and hippocampus, in addition to the expression of NF-κB in the hippocampus. Furthermore, these effects attributed to GBP were observed to disappear in the presence of bisphenol A diglycidyl ether (BADGE), a specific inhibitor of PPAR-γ. Conclusions Our findings revealed that GBP could activate PPAR-γ to suppress the NF-κB signaling pathway, contributing to the decrease of ethanol consumption and ethanol-induced neuroimmune responses.

15 Deoxy Δ12,14 PGJ2 Induces Procoagulant Activity in Cultured Human Endothelial Cells

2002 ◽  
Vol 87 (03) ◽  
pp. 523-529 ◽  
Author(s):  
Shaoping Xie ◽  
David O’Regan ◽  
Vijay Kakkar ◽  
Michael Scully
Keyword(s):  
Endothelial Cells ◽  
Peroxisome Proliferator ◽  
Endothelial Protein C Receptor ◽  
Peroxisome Proliferator Activated Receptor ◽  
Affinity Ligand ◽  
Ppar Γ ◽  
Tnf Α ◽  
Ea.Hy926 Cells ◽  
High Affinity Ligand ◽  
Feedback Regulator

Summary15 deoxy Δ12,14 PGJ2 (15d-PGJ2), a high affinity ligand of peroxisome proliferator-activated receptor γ (PPAR γ has been proposed to act as a negative feedback regulator of the inflammatory response. We investigated the effect of 15d-PGJ2 on the anticoagulant property of endothelial cells. 15d-PGJ2 stimulated a moderate but sustained increase in tissue factor (TF) activity in HUVECs and EA.hy926 cells while causing a partial loss of thrombomodulin (TM) activity. When cells were co-treated with 15d-PGJ2 and TNF-α, the subsequent elevation of TF activity was synergistically increased over that of cells treated with TNF-α, alone and the decline of TF activity after 24 h was less marked than TNF-α, alone. The induction of TF by 15d-PGJ2 alone and in combination with TNF-α, was reduced in the presence of PD 98059, suggesting the participation of the MEK/ERK pathway. The thiazolidinedione PPAR γ agonist ciglitazone had no effect on TF levels but reduced the expression of endothelial protein C receptor. The ability of 15d-PGJ2 to enhance a procoagulant phenotype arising from TNF-α, suggests a pro-inflammatory role for the prostaglandin.

Agouti regulates adipocyte transcription factors

2001 ◽  
Vol 280 (4) ◽  
pp. C954-C961 ◽  
Author(s):  
Randall L. Mynatt ◽  
Jacqueline M. Stephens
Keyword(s):  
Adipose Tissue ◽  
Transgenic Mice ◽  
Ectopic Expression ◽  
Peroxisome Proliferator ◽  
Paracrine Factor ◽  
Peroxisome Proliferator Activated Receptor ◽  
Protein Levels ◽  
Skeletal Mass ◽  
Ppar Γ ◽  
Obesity And Diabetes

Agouti is a secreted paracrine factor that regulates pigmentation in hair follicle melanocytes. Several dominant mutations cause ectopic expression of agouti, resulting in a phenotype characterized by yellow fur, adult-onset obesity and diabetes, increased linear growth and skeletal mass, and increased susceptibility to tumors. Humans also produce agouti protein, but the highest levels of agouti in humans are found in adipose tissue. To mimic the human agoutiexpression pattern in mice, transgenic mice (aP2-agouti) that express agouti in adipose tissue were generated. The transgenic mice develop a mild form of obesity, and they are sensitized to the action of insulin. We correlated the levels of specific regulators of insulin signaling and adipocyte differentiation with these phenotypic changes in adipose tissue. Signal transducers and activators of transcription (STAT)1, STAT3, and peroxisome proliferator-activated receptor (PPAR)-γ protein levels were elevated in the transgenic mice. Treatment of mature 3T3-L1 adipocytes recapitulated these effects. These data demonstrate that agouti has potent effects on adipose tissue. We hypothesize that agouti increases adiposity and promotes insulin sensitivity by acting directly on adipocytes via PPAR-γ.

scholarly journals Endogenously produced adiponectin protects cardiomyocytes from hypertrophy by a PPARγ-dependent autocrine mechanism

2010 ◽  
Vol 299 (3) ◽  
pp. H690-H698 ◽  
Author(s):  
Rajesh H. Amin ◽  
Suresh T. Mathews ◽  
Adebisi Alli ◽  
Todd Leff
Keyword(s):  
Gene Expression ◽  
Cardiac Hypertrophy ◽  
Signaling Pathway ◽  
Receptor Gene ◽  
Peroxisome Proliferator ◽  
Adrenergic Stimulation ◽  
Peroxisome Proliferator Activated Receptor ◽  
Beneficial Effects ◽  
Ppar Γ ◽  
Culture Models

In experimental animal and cell culture models, activation of peroxisome proliferator-activated receptor (PPAR) γ in heart has been shown to have beneficial effects on cardiac function and cardiomyocyte physiology. The goal of this study was to identify the signaling pathway by which PPARγ activation protects cardiomyocytes from the deleterious effects of hypertrophic stimuli. In primary cardiomyocyte cultures, we found that genetic or pharmacological activation of PPARγ protected cells from cardiac hypertrophy induced by α-adrenergic stimulation. Examination of gene expression in these cells revealed a surprising increase in the expression of adiponectin in cardiomyocytes and secretion of the high-molecular-weight form of the hormone into media. Using RNAi to block PPARγ-induced adiponectin production or adiponectin receptor gene expression, we found that the PPARγ-mediated anti-hypertrophic effect required cardiomyocyte-produced adiponectin, as well as an intact adiponectin signaling pathway. Furthermore, mice expressing constitutive-active PPARγ and cardiomyocyte specific adiponectin expression were protected from high-fat diet-induced cardiac hypertrophy and remodeling. These findings demonstrate that functional adiponectin hormone can be produced from the heart and raise the possibility that beneficial effects of PPARγ activation in heart could be due in part to local production of adiponectin that acts on cardiomyocytes in an autocrine manner.

scholarly journals Beta-sitosterol upregulated paraoxonase-1 via peroxisome proliferator-activated receptor-γ in irradiated rats

2017 ◽  
Vol 95 (6) ◽  
pp. 661-666 ◽  
Author(s):  
Enas Mahmoud Moustafa ◽  
Noura Magdy Thabet
Keyword(s):  
Oxidative Stress ◽  
Gene Expression ◽  
Enzyme Activities ◽  
Liver Tissue ◽  
Density Lipoprotein ◽  
Lipoprotein Cholesterol ◽  
Oxidative Stress Marker ◽  
Peroxisome Proliferator ◽  
Peroxisome Proliferator Activated Receptor ◽  
Ppar Γ

This study was designed to evaluate the effect of beta-sitosterol (BS) on the peroxisome proliferator-activated receptor gamma (PPAR-γ) gene expression role in the activity of paraoxonase (PON-1) enzyme in oxidative stress status of irradiated rats. Animals were exposed to whole body γ-radiation single dose 6 Gy and received BS dose (40 mg·(kg body mass)−1·day−1, orally). In liver tissue, gene expression of PPAR-γ ligand was determined. Oxidative stress marker (malondialdehyde, MDA) and antioxidant enzyme activities (superoxide dismutase (SOD), catalase (CAT), PON-1, and arylesterase (ARE)) were assayed in serum and liver tissue. Also, serum lipid profile (cholesterol, triglycerides (TG), low-density lipoprotein cholesterol (LDL-c), and high-density lipoprotein cholesterol (HDL-c)) was measured. In irradiated animals that received BS, expression of PPAR-γ ligand increase significantly associated with increase in PON-1 and ARE enzyme activities. Also, the activities of SOD, CAT enzymes, and HDL-c levels display elevation. By contrast, significant decrease in MDA content, cholesterol, TG, and LDL-c levels were revealed after BS administration. Our findings in this study provide the evidence that BS has radio-protective effect via regulating the gene expression of PPAR-γ, causing an increase in PON-1 and ARE enzyme activities. This action of BS is due to its free radical scavenging properties, antioxidant effect, lowering of cholesterol, and PPAR-γ agonist properties.

Disruption of transforming growth factor-β signaling by curcumin induces gene expression of peroxisome proliferator-activated receptor-γ in rat hepatic stellate cells

2007 ◽  
Vol 292 (1) ◽  
pp. G113-G123 ◽  
Author(s):  
Shizhong Zheng ◽  
Anping Chen
Keyword(s):  
Gene Expression ◽  
Hepatic Stellate Cells ◽  
Molecular Mechanisms ◽  
Transforming Growth Factor ◽  
Gene Promoter ◽  
Stellate Cells ◽  
Transforming Growth Factor Β ◽  
Peroxisome Proliferator ◽  
Peroxisome Proliferator Activated Receptor ◽  
Ppar Γ

Activation of hepatic stellate cells (HSC), the major effectors of hepatic fibrogenesis, is coupled with sequential alterations in gene expression, including an increase in receptors for transforming growth factor-β (TGF-β) and a dramatic reduction in the peroxisome proliferator-activated receptor-γ (PPAR-γ). The relationship between them remains obscure. We previously demonstrated that curcumin induced gene expression of PPAR-γ in activated HSC, leading to reducing cell proliferation, inducing apoptosis and suppressing expression of extracellular matrix genes. The underlying molecular mechanisms are largely unknown. We recently observed that stimulation of PPAR-γ activation suppressed gene expression of TGF-β receptors in activated HSC, leading to the interruption of TGF-β signaling. This observation supported our assumption of an antagonistic relationship between PPAR-γ activation and TGF-β signaling in HSC. In this study, we further hypothesize that TGF-β signaling might negatively regulate gene expression of PPAR-γ in activated HSC. The present report demonstrates that exogenous TGF-β1 inhibits gene expression of PPAR-γ in activated HSC, which is eliminated by the pretreatment with curcumin likely by interrupting TGF-β signaling. Transfection assays further indicate that blocking TGF-β signaling by dominant negative type II TGF-β receptor increases the promoter activity of PPAR-γ gene. Promoter deletion assays, site-directed mutageneses, and gel shift assays localize two Smad binding elements (SBEs) in the PPAR-γ gene promoter, acting as curcumin response elements and negatively regulating the promoter activity in passaged HSC. The Smad3/4 protein complex specifically binds to the SBEs. Overexpression of Smad4 dose dependently eliminates the inhibitory effects of curcumin on the PPAR-γ gene promoter and TGF-β signaling. Taken together, these results demonstrate that the interruption of TGF-β signaling by curcumin induces gene expression of PPAR-γ in activated HSC in vitro. Our studies provide novel insights into the molecular mechanisms of curcumin in the induction of PPAR-γ gene expression and in the inhibition of HSC activation.

scholarly journals PPAR-γ Activation Prevents Septic Cardiac Dysfunction via Inhibition of Apoptosis and Necroptosis

2017 ◽  
Vol 2017 ◽  
pp. 1-11 ◽  
Author(s):  
Shiyan Peng ◽  
Junmei Xu ◽  
Wei Ruan ◽  
Suobei Li ◽  
Feng Xiao
Keyword(s):  
Cell Death ◽  
Proinflammatory Cytokines ◽  
Cardiac Dysfunction ◽  
Myocardial Dysfunction ◽  
Cecal Ligation ◽  
Peroxisome Proliferator ◽  
Peroxisome Proliferator Activated Receptor ◽  
Interacting Protein ◽  
Cardiac Inflammation ◽  
Ppar Γ

Sepsis-induced cardiac dysfunction remains one of the major causes of death in intensive care units. Overwhelmed inflammatory response and unrestrained cell death play critical roles in sepsis-induced cardiac dysfunction. Peroxisome proliferator-activated receptor- (PPAR-) γ has been proven to be cardioprotective in sepsis. However, the mechanism of PPAR-γ-mediated cardioprotection and its relationship with inflammation and cell death are unclear. We hypothesized that activation of PPAR-γ by reducing cardiac inflammation, myocardial apoptosis, and necroptosis may prevent myocardial dysfunction in sepsis. Rats were subjected to cecal ligation and puncture (CLP) with or without PPAR-γ agonist (rosiglitazone) or antagonist T0070907 (T007). After CLP, cardiac function was significantly depressed, which was associated with the destructed myocardium, upregulated proinflammatory cytokines, and increased apoptosis, necrosis, and necroptosis. This process is corresponded with decreased inhibitor κB (IκBα) and increased NF-κB, receptor-interacting protein kinase-1 (RIP1), RIP3, and mixed lineage kinase-like (MLKL) protein. Activation of PPAR-γ by rosiglitazone pretreatment enhanced PPAR-γ activity and prevented these changes, thereby improving the survival of septic rats. In contrast, inhibition of PPAR-γ by T007 further exacerbated the condition, dropping the survival rate to nearly 0%. In conclusion, PPAR-γ activation by reducing proinflammatory cytokines, apoptosis, and necroptosis in the myocardium prevents septic myocardial dysfunction.

scholarly journals Gene expressions of de novo hepatic lipogenesis in feline hepatic lipidosis

2019 ◽  
Vol 22 (6) ◽  
pp. 500-505
Author(s):  
Chiara Valtolina ◽  
Joris H Robben ◽  
Monique E van Wolferen ◽  
Hedwig S Kruitwagen ◽  
Ronald J Corbee ◽  
...  
Keyword(s):  
Gene Expression ◽  
Fatty Acid ◽  
Liver Tissue ◽  
Fatty Acid Synthase ◽  
De Novo ◽  
Control Group ◽  
Peroxisome Proliferator ◽  
Hepatic Lipidosis ◽  
Peroxisome Proliferator Activated Receptor ◽  
Ppar Γ

Objectives The aim of this study was to evaluate if de novo hepatic lipid synthesis contributes to fatty acid overload in the liver of cats with feline hepatic lipidosis (FHL). Methods Lipogenic gene expression of peroxisome proliferator-activated receptor-alpha ( PPAR-α), peroxisome proliferator-activated receptor-gamma ( PPAR-γ), fatty acid synthase ( FASN) and sterol regulatory element-binding factor ( SREBF1) were evaluated using quantitative RT-PCR in liver tissue of six cats with FHL and compared with the liver tissue of eight healthy cats. Results In liver tissue, PPAR-α, PPAR-γ and FASN mRNA expression levels were not significantly different ( P >0.12, P >0.89 and P >0.5, respectively) in the FHL group compared with the control group. SREBF1 gene expression was downregulated around 10-fold in the FHL group vs the control group ( P = 0.039). Conclusions and relevance The downregulation of SREBF1 in the liver tissue of cats with FHL does not support the hypothesis that de novo lipogenesis in the liver is an important pathway of fatty acid accumulation in FHL.

PPAR-γ ligands modulate effects of LPS in stimulated rat synovial fibroblasts

2002 ◽  
Vol 282 (1) ◽  
pp. C125-C133 ◽  
Author(s):  
Marie-Agnès Simonin ◽  
Karim Bordji ◽  
Sandrine Boyault ◽  
Arnaud Bianchi ◽  
Elvire Gouze ◽  
...  
Keyword(s):  
Mrna Expression ◽  
Constitutive Expression ◽  
Synovial Fibroblasts ◽  
Binding Activity ◽  
Inos Mrna ◽  
Peroxisome Proliferator ◽  
Peroxisome Proliferator Activated Receptor ◽  
Ppar Γ ◽  
Tnf Α ◽  
Cox 2

This work demonstrated the constitutive expression of peroxisome proliferator-activated receptor (PPAR)-γ and PPAR-α in rat synovial fibroblasts at both mRNA and protein levels. A decrease in PPAR-γ expression induced by 10 μg/ml lipopolysaccharide (LPS) was observed, whereas PPAR-α mRNA expression was not modified. 15-Deoxy-Δ12,14-prostaglandin J2(15d-PGJ2) dose-dependently decreased LPS-induced cyclooxygenase (COX)-2 (−80%) and inducible nitric oxide synthase (iNOS) mRNA expression (−80%), whereas troglitazone (10 μM) only inhibited iNOS mRNA expression (−50%). 15d-PGJ2 decreased LPS-induced interleukin (IL)-1β (−25%) and tumor necrosis factor (TNF)-α (−40%) expression. Interestingly, troglitazone strongly decreased TNF-α expression (−50%) but had no significant effect on IL-1β expression. 15d-PGJ2 was able to inhibit DNA-binding activity of both nuclear factor (NF)-κB and AP-1. Troglitazone had no effect on NF-κB activation and was shown to increase LPS-induced AP-1 activation. 15d-PGJ2 and troglitazone modulated the expression of LPS-induced iNOS, COX-2, and proinflammatory cytokines differently. Indeed, troglitazone seems to specifically target TNF-α and iNOS pathways. These results offer new insights in regard to the anti-inflammatory potential of the PPAR-γ ligands and underline different mechanisms of action of 15d-PGJ2 and troglitazone in synovial fibroblasts.

Sign in / Sign up

Export Citation Format

Share Document