Peroxisome proliferator-activated receptor-γ ligands regulate endothelial membrane superoxide production

2005 ◽  
Vol 288 (4) ◽  
pp. C899-C905 ◽  
Author(s):  
Jinah Hwang ◽  
Dean J. Kleinhenz ◽  
Bernard Lassègue ◽  
Kathy K. Griendling ◽  
Sergey Dikalov ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Nadph Oxidase ◽  
Molecular Mechanisms ◽  
Pcr Analysis ◽  
Resonance Spectroscopy ◽  
Peroxisome Proliferator ◽  
Mrna Levels ◽  
Peroxisome Proliferator Activated Receptor ◽  
Ppar Γ ◽  
Endothelial Nitric Oxide

Recently, we demonstrated that the peroxisome proliferator-activated receptor-γ (PPAR-γ) ligands, either 15-deoxy-Δ12,14-prostaglandin J2 (15d-PGJ2) or ciglitazone, increased endothelial nitric oxide (·NO) release without altering endothelial nitric oxide synthase (eNOS) expression ( 4 ). However, the precise molecular mechanisms of PPAR-γ-stimulated endothelial·NO release remain to be defined. Superoxide anion radical (O2−·) combines with ·NO to decrease·NO bioavailability. NADPH oxidase, which produces O2−·, and Cu/Zn-superoxide dismutase (Cu/Zn-SOD), which degrades O2−·, thereby contribute to regulation of endothelial cell·NO metabolism. Therefore, we examined the ability of PPAR-γ ligands to modulate endothelial O2−· metabolism through alterations in the expression and activity of NADPH oxidase or Cu/Zn-SOD. Treatment with 10 μM 15d-PGJ2 or ciglitazone for 24 h decreased human umbilical vein endothelial cell (HUVEC) membrane NADPH-dependent O2−· production detected with electron spin resonance spectroscopy. Treatment with 15d-PGJ2 or ciglitazone also reduced relative mRNA levels of the NADPH oxidase subunits, nox-1, gp91 phox (nox-2), and nox-4, as measured using real-time PCR analysis. Concordantly, Western blot analysis demonstrated that 15d-PGJ2 or ciglitazone decreased nox-2 and nox-4 protein expression. PPAR-γ ligands also stimulated both activity and expression of Cu/Zn-SOD in HUVEC. These data suggest that in addition to any direct effects on endothelial·NO production, PPAR-γ ligands enhance endothelial·NO bioavailability, in part by altering endothelial O2−· metabolism through suppression of NADPH oxidase and induction of Cu/Zn-SOD. These findings further elucidate the molecular mechanisms by which PPAR-γ ligands directly alter vascular endothelial function.

scholarly journals RT-PCR analysis of corticotroph-associated genes expression in carcinoid tumours in the ectopic-ACTH syndrome

2006 ◽  
Vol 154 (1) ◽  
pp. 159-166 ◽  
Author(s):  
M Messager ◽  
C Carrière ◽  
X Bertagna ◽  
Y de Keyzer
Keyword(s):  
Transcription Factor ◽  
Molecular Mechanisms ◽  
Ectopic Acth Syndrome ◽  
Pcr Analysis ◽  
Peroxisome Proliferator ◽  
Rt Pcr ◽  
Ectopic Acth ◽  
Peroxisome Proliferator Activated Receptor ◽  
Carcinoid Tumours ◽  
Transcription Factor Genes

Objective: ACTH is frequently produced in non-pituitary tumours, leading to the ectopic-ACTH syndrome, but the molecular mechanisms of its expression remain obscure. This study was aimed at understanding the transcription mechanisms of the ACTH-precursor gene in carcinoid tumours of the lung or thymus. Design: Transcripts coding for a series of corticotroph-associated transcription factor genes were detected, together with markers of the corticotroph phenotype. We studied a series of 41 carcinoid tumours including 15 with proven ectopic-ACTH syndrome. Methods: Specific RT-PCR reactions were designed for each gene including alternatively spliced isoforms. Results: The markers of the corticotroph phenotype were detected in all ACTH-positive tumours. Expression of the Tpit and Pitx1 genes were not restricted to ACTH-positive tumours but were also detected in many ACTH-negative carcinoids. Only a subset of ACTH-negative tumours expressed NAK-1/Nur77, and NeuroD1 expression was detected in <50% of the tumours regardless of their secretory status. The glucocorticoid receptor alpha was detected in every tumour in contrast to its beta isoform detectable in a few tumours only. Chicken ovalbumin upstream promoter-transcription factor 1 (COUP-TF1) and peroxisome proliferator-activated receptor (PPAR) γ2 were expressed in 50% of the tumours of each group whereas PPARγ1 was expressed in almost every tumour. Conclusions: ACTH-positive carcinoids do not share a characteristic expression pattern of the corticotroph-associated transcription factor genes, suggesting that the transcriptional mechanisms of the ACTH-precursor gene differ from those in normal pituitary corticotrophs. Expression of Tpit and Pitx1 genes in most carcinoids suggests that some aspects of the pituitary corticotroph phenotype may belong to general carcinoid differentiation.

scholarly journals Inactivation of Foxo3a and Subsequent Downregulation of PGC-1α Mediate Nitric Oxide-Induced Endothelial Cell Migration

2010 ◽  
Vol 30 (16) ◽  
pp. 4035-4044 ◽  
Author(s):  
Sara Borniquel ◽  
Nieves García-Quintáns ◽  
Inmaculada Valle ◽  
Yolanda Olmos ◽  
Brigitte Wild ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Cell Migration ◽  
Endothelial Cell ◽  
Protein Kinase ◽  
Endothelial Cell Migration ◽  
Peroxisome Proliferator ◽  
Peroxisome Proliferator Activated Receptor ◽  
Endothelial Migration ◽  
Endothelial Nitric Oxide

ABSTRACT In damaged or proliferating endothelium, production of nitric oxide (NO) from endothelial nitric oxide synthase (eNOS) is associated with elevated levels of reactive oxygen species (ROS), which are necessary for endothelial migration. We aimed to elucidate the mechanism that mediates NO induction of endothelial migration. NO downregulates expression of peroxisome proliferator-activated receptor γ coactivator 1α (PGC-1α), which positively modulates several genes involved in ROS detoxification. We tested whether NO-induced cell migration requires PGC-1α downregulation and investigated the regulatory pathway involved. PGC-1α negatively regulated NO-dependent endothelial cell migration in vitro, and inactivation of the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt) pathway, which is activated by NO, reduced NO-mediated downregulation of PGC-1α. Expression of constitutively active Foxo3a, a target for Akt-mediated inactivation, reduced NO-dependent PGC-1α downregulation. Foxo3a is also a direct transcriptional regulator of PGC-1α, and we found that a functional FoxO binding site in the PGC-1α promoter is also a NO response element. These results show that NO-mediated downregulation of PGC-1α is necessary for NO-induced endothelial migration and that NO/protein kinase G (PKG)-dependent downregulation of PGC-1α and the ROS detoxification system in endothelial cells are mediated by the PI3K/Akt signaling pathway and subsequent inactivation of the FoxO transcription factor Foxo3a.

scholarly journals Expression of peroxisome proliferator-activated receptor-γ in macrophage suppresses experimentally induced colitis

2007 ◽  
Vol 292 (2) ◽  
pp. G657-G666 ◽  
Author(s):  
Yatrik M. Shah ◽  
Keiichirou Morimura ◽  
Frank J. Gonzalez
Keyword(s):  
Clinical Symptoms ◽  
Body Weight Loss ◽  
Peroxisome Proliferator ◽  
Mrna Levels ◽  
Wild Type ◽  
Targeted Disruption ◽  
Peroxisome Proliferator Activated Receptor ◽  
Ppar Γ ◽  
Cytokine Analysis ◽  
Increased Susceptibility

Peroxisome proliferator-activated receptor-γ (PPAR-γ) has been shown to be a protective transcription factor in mouse models of inflammatory bowel disease (IBD). PPAR-γ is expressed in several different cell types, and mice with a targeted disruption of the PPAR-γ gene in intestinal epithelial cells demonstrated increased susceptibility to dextran sulfate sodium (DSS)-induced IBD. However, the highly selective PPAR-γ ligand rosiglitazone decreased the severity of DSS-induced colitis and suppressed cytokine production in both PPAR-γ intestinal specific null mice and wild-type littermates. Therefore the role of PPAR-γ in different tissues and their contribution to the pathogenesis of IBD still remain unclear. Mice with a targeted disruption of PPAR-γ in macrophages (PPAR-γΔMφ) and wild-type littermates (PPAR-γF/F) were administered 2.5% DSS in drinking water to induce IBD. Typical clinical symptoms were evaluated on a daily basis, and proinflammatory cytokine analysis was performed. PPAR-γΔMφ mice displayed an increased susceptibility to DSS-induced colitis compared with wild-type littermates, as defined by body weight loss, diarrhea, rectal bleeding score, colon length, and histology. IL-1β, CCR2, MCP-1, and inducible nitric oxide synthase mRNA levels in colons of PPAR-γΔMφ mice treated with DSS were higher than in similarly treated PPAR-γF/F mice. The present study has identified a novel protective role for macrophage PPAR-γ in the DSS-induced IBD model. The data suggest that PPAR-γ regulates recruitment of macrophages to inflammatory foci in the colon.

Effect of nitric oxide synthase inhibition on mitochondrial biogenesis in rat skeletal muscle

2007 ◽  
Vol 102 (1) ◽  
pp. 314-320 ◽  
Author(s):  
G. D. Wadley ◽  
G. K. McConell
Keyword(s):  
Nitric Oxide ◽  
Skeletal Muscle ◽  
Mitochondrial Biogenesis ◽  
Acute Exercise ◽  
Peroxisome Proliferator ◽  
Mrna Levels ◽  
Peroxisome Proliferator Activated Receptor ◽  
Exercise Induced ◽  
Edl Muscle ◽  
Oxide Synthase

The purpose of this study was to determine whether nitric oxide synthase (NOS) inhibition decreased basal and exercise-induced skeletal muscle mitochondrial biogenesis. Male Sprague-Dawley rats were assigned to one of four treatment groups: NOS inhibitor NG-nitro-l-arginine methyl ester (l-NAME, ingested for 2 days in drinking water, 1 mg/ml) followed by acute exercise, no l-NAME ingestion and acute exercise, rest plus l-NAME, and rest without l-NAME. The exercised rats ran on a treadmill for 53 ± 2 min and were then killed 4 h later. NOS inhibition significantly ( P < 0.05; main effect) decreased basal peroxisome proliferator-activated receptor-γ coactivator 1β (PGC-1β) mRNA levels and tended ( P = 0.08) to decrease mtTFA mRNA levels in the soleus, but not the extensor digitorum longus (EDL) muscle. This coincided with significantly reduced basal levels of cytochrome c oxidase (COX) I and COX IV mRNA, COX IV protein and COX enzyme activity following NOS inhibition in the soleus, but not the EDL muscle. NOS inhibition had no effect on citrate synthase or β-hydroxyacyl CoA dehydrogenase activity, or cytochrome c protein abundance in the soleus or EDL. NOS inhibition did not reduce the exercise-induced increase in peroxisome proliferator-activated receptor-γ coactivator 1α (PGC-1α) mRNA in the soleus or EDL. In conclusion, inhibition of NOS appears to decrease some aspects of the mitochondrial respiratory chain in the soleus under basal conditions, but does not attenuate exercise-induced mitochondrial biogenesis in the soleus or in the EDL.

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 Modulation of peroxisome proliferator-activated receptor δ and γ transcripts in swine endometrial tissue during early gestation

Reproduction ◽  
2006 ◽  
Vol 131 (5) ◽  
pp. 929-942 ◽  
Author(s):  
Etienne Lord ◽  
Bruce D Murphy ◽  
Joëlle A Desmarais ◽  
Sandra Ledoux ◽  
Danièle Beaudry ◽  
...  
Keyword(s):  
Embryo Implantation ◽  
Endometrial Tissue ◽  
Pcr Analysis ◽  
Peroxisome Proliferator ◽  
Mrna Levels ◽  
Tissue Sampling ◽  
Peroxisome Proliferator Activated Receptor ◽  
Attachment Sites ◽  
Peroxisome Proliferator Activated Receptors ◽  
Implantation Period

Recent evidence points to a role for peroxisome proliferator-activated receptors (PPARs) δ and γ in embryo implantation and survival. In this study, we report the porcine PPARδ complete coding sequence and mRNA abundance of PPARδ, PPARγ1 and γ2, angiopoietin-like protein 4 (ANGPTL4) and adipocyte determination and differentiation-dependent factor 1 (ADD1) genes in the pregnant sow endometrium. Real-time PCR analysis was used to study the effect of parity (Yorkshire-Landrace multiparous (YL) and nulliparous (YLn)), site of endometrial tissue sampling (between and at embryo attachment sites) in crossbred Duroc×Yorkshire-Landrace (DYL) sows and stages of pregnancy (non-pregnant, day 15 and day 25 after mating) in Meishan-Landrace (ML) on mRNA levels. Parity effects were observed for PPARδ, ANGPTL4, and ADD1, with higher mRNA levels in YL than YLn sows. In DYL sows, lower mRNA levels were present at attachment sites compared to between attachment sites for PPARδ, PPARγ1, and ANGPTL4. Finally, day 15 pregnant ML sows had lower PPARδ mRNA levels compared to day 15 cycling ML sows. A significant increase of PPARγ1 mRNA levels was found on day 25 pregnant ML and DYL sows relative to day 15 ML or DYL pregnant sows. PPARδ and γ immunostaining was detected in endometrial tissue of day 15 cycling sows, day 15 and 25 pregnant sows and epithelial cells of day 25 embryos. Collectively, our results suggest a role for PPARδ, PPARγ1, and ANGPTL4, but not PPARγ2, during the peri-implantation period in pregnant sows.

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