Constitutive activation of peroxisome proliferator-activated receptor-gamma suppresses pro-inflammatory adhesion molecules in human vascular endothelial cells.
Peroxisome proliferator-activated receptor-gamma (PPAR-gamma) is a ligand-activated nuclear receptor that has an essential role in adipogenesis and glucose homeostasis. PPAR-gamma is expressed in vascular tissues including endothelial cells (ECs). PPAR-gamma activity can be regulated by many pathophysiological and pharmacological agonists. However, the role of PPAR-gamma activation in ECs remains unclear. In this study, we examined the effect of the constitutive activation of PPAR-gamma on the phenotypic modulation of ECs. Adenovirus-mediated expression of a constitutively active mutant of PPAR-gamma resulted in significant ligand-independent activation of PPAR-gamma and specific induction of the PPAR-gamma target genes. However, PPAR-gamma activation significantly suppressed the expression of vascular adhesion molecules in ECs and the ensuing leukocyte recruitment. Furthermore, constitutive activation of PPAR-gamma resulted in simultaneous repression of AP-1 and NF-kappaB activity, which suggests that PPAR-gamma may reduce pro-inflammatory phenotypes via, at least in part, suppression of the AP-1 and NF-kappaB pathways. Therefore, using a gain-of-function approach, our study provides novel evidence showing that constitutive activation of PPAR-gamma is sufficient to prevent ECs from converting into a pro-inflammatory phenotype. These results also suggest that, in addition to pharmacological agonists, the genetic modification of the PPAR-gamma activity in ECs may be a potential approach for therapeutic intervention in various inflammatory disorders.
Wang
Nanping
N
Division of Biomedical Sciences, University of California, Riverside, CA 92521, USA. nanping.wang@ucr.edu
Verna
Lynne
L
Chen
Neng-Guin
NG
Chen
Jasmine
J
Li
Hongling
H
Forman
Barry Marc
BM
Stemerman
Michael B
MB
D002478:Cells, Cultured; D004247:DNA / Q000378:metabolism; D019040:E-Selectin / Q000096:biosynthesis*; D004730:Endothelium, Vascular / Q000166:cytology / Q000378:metabolism*; D006801:Humans; D007249:Inflammation / Q000628:therapy*; D018799:Intercellular Adhesion Molecule-1 / Q000096:biosynthesis*; D016328:NF-kappa B / Q000378:metabolism; D011401:Promoter Regions, Genetic; D018160:Receptors, Cytoplasmic and Nuclear / Q000502:physiology*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D018808:Transcription Factor AP-1 / Q000378:metabolism; D014157:Transcription Factors / Q000502:physiology*; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology; D019010:Vascular Cell Adhesion Molecule-1 / Q000096:biosynthesis*
D019040:E-Selectin; D016328:NF-kappa B; D018160:Receptors, Cytoplasmic and Nuclear; D018808:Transcription Factor AP-1; D014157:Transcription Factors; D014409:Tumor Necrosis Factor-alpha; D019010:Vascular Cell Adhesion Molecule-1; D018799:Intercellular Adhesion Molecule-1; D004247:DNA; D013755:Tetradecanoylphorbol Acetate