BACKGROUND: Thiazolidinediones have been reported to protect against ischemia-reperfusion injury. Their protective actions are considered to be peroxisome proliferator-activated receptor-gamma (PPAR-gamma)-dependent; however, it is unclear how PPAR-gamma activation confers resistance to ischemia-reperfusion injury. METHODS AND RESULTS: We evaluated the effects of rosiglitazone or PPAR-gamma overexpression on cerebral infarction in a rat model and investigated the antiapoptotic actions in the N2-A neuroblastoma cell model. Rosiglitazone or PPAR-gamma overexpression significantly reduced infarct volume. The protective effect was abrogated by PPAR-gamma small interfering RNA. In mice with knock-in of a PPAR-gamma dominant-negative mutant, infarct volume was enhanced. Proteomic analysis revealed that brain 14-3-3epsilon was highly upregulated in rats treated with rosiglitazone. Upregulation of 14-3-3epsilon was abrogated by PPAR-gamma small interfering RNA or antagonist. Promoter analysis and chromatin immunoprecipitation revealed that rosiglitazone induced PPAR-gamma binding to specific regulatory elements on the 14-3-3epsilon promoter and thereby increased 14-3-3epsilon transcription. 14-3-3epsilon Small interfering RNA abrogated the antiapoptotic actions of rosiglitazone or PPAR-gamma overexpression, whereas 14-3-3epsilon recombinant proteins rescued brain tissues and N2-A cells from ischemia-induced damage and apoptosis. Elevated 14-3-3epsilon enhanced binding of phosphorylated Bad and protected mitochondrial membrane potential. CONCLUSIONS: Ligand-activated PPAR-gamma confers resistance to neuronal apoptosis and cerebral infarction by driving 14-3-3epsilon transcription. 14-3-3epsilon Upregulation enhances sequestration of phosphorylated Bad and thereby suppresses apoptosis.
BACKGROUND:Thiazolidinediones have been reported to protect against ischemia-reperfusion injury. Their protective actions are considered to be peroxisome proliferator-activated receptor-gamma (PPAR-gamma)-dependent; however, it is unclear how PPAR-gamma activation confers resistance to ischemia-reperfusion injury. METHODS AND RESULTS: We evaluated the effects of rosiglitazone or PPAR-gamma overexpression on cerebral infarction in a rat model and investigated the antiapoptotic actions in the N2-Aneuroblastoma cell model. Rosiglitazone or PPAR-gamma overexpression significantly reduced infarct volume. The protective effect was abrogated by PPAR-gamma small interfering RNA. In mice with knock-in of a PPAR-gamma dominant-negative mutant, infarct volume was enhanced. Proteomic analysis revealed that brain 14-3-3epsilon was highly upregulated in rats treated with rosiglitazone. Upregulation of 14-3-3epsilon was abrogated by PPAR-gamma small interfering RNA or antagonist. Promoter analysis and chromatin immunoprecipitation revealed that rosiglitazone induced PPAR-gamma binding to specific regulatory elements on the 14-3-3epsilon promoter and thereby increased 14-3-3epsilon transcription. 14-3-3epsilon Small interfering RNA abrogated the antiapoptotic actions of rosiglitazone or PPAR-gamma overexpression, whereas 14-3-3epsilon recombinant proteins rescued brain tissues and N2-A cells from ischemia-induced damage and apoptosis. Elevated 14-3-3epsilon enhanced binding of phosphorylated Bad and protected mitochondrial membrane potential. CONCLUSIONS: Ligand-activated PPAR-gamma confers resistance to neuronal apoptosis and cerebral infarction by driving 14-3-3epsilon transcription. 14-3-3epsilon Upregulation enhances sequestration of phosphorylated Bad and thereby suppresses apoptosis.
Authors: T L Yue Tl; J Chen; W Bao; P K Narayanan; A Bril; W Jiang; P G Lysko; J L Gu; R Boyce; D M Zimmerman; T K Hart; R E Buckingham; E H Ohlstein Journal: Circulation Date: 2001-11-20 Impact factor: 29.690
Authors: John S Welch; Mercedes Ricote; Taro E Akiyama; Frank J Gonzalez; Christopher K Glass Journal: Proc Natl Acad Sci U S A Date: 2003-05-09 Impact factor: 11.205