Targeted Disruption of the Peroxisome Proliferator?Activated Receptor ? Gene, PPAR?

1996 ◽  
Vol 804 (1 Peroxisomes) ◽  
pp. 524-529 ◽  
Author(s):  
SUSANNA S.-T. LEE ◽  
FRANK J. GONZALEZ
Keyword(s):  
Receptor Gene ◽  
Peroxisome Proliferator ◽  
Targeted Disruption ◽  
Peroxisome Proliferator Activated Receptor

scholarly journals Targeted disruption of the alpha isoform of the peroxisome proliferator-activated receptor gene in mice results in abolishment of the pleiotropic effects of peroxisome proliferators.

1995 ◽  
Vol 15 (6) ◽  
pp. 3012-3022 ◽  
Author(s):  
S S Lee ◽  
T Pineau ◽  
J Drago ◽  
E J Lee ◽  
J W Owens ◽  
...  
Keyword(s):  
Transcriptional Activation ◽  
Target Genes ◽  
Receptor Gene ◽  
Peroxisome Proliferator ◽  
Peroxisome Proliferators ◽  
Targeted Disruption ◽  
Peroxisome Proliferator Activated Receptor ◽  
Cycle Regulation ◽  
Insight Into

To gain insight into the function of peroxisome proliferator-activated receptor (PPAR) isoforms in rodents, we disrupted the ligand-binding domain of the alpha isoform of mouse PPAR (mPPAR alpha) by homologous recombination. Mice homozygous for the mutation lack expression of mPPAR alpha protein and yet are viable and fertile and exhibit no detectable gross phenotypic defects. Remarkably, these animals do not display the peroxisome proliferator pleiotropic response when challenged with the classical peroxisome proliferators, clofibrate and Wy-14,643. Following exposure to these chemicals, hepatomegaly, peroxisome proliferation, and transcriptional-activation of target genes were not observed. These results clearly demonstrate that mPPAR alpha is the major isoform required for mediating the pleiotropic response resulting from the actions of peroxisome proliferators. mPPAR alpha-deficient animals should prove useful to further investigate the role of this receptor in hepatocarcinogenesis, fatty acid metabolism, and cell cycle regulation.

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 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.

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