Rosiglitazone and PPAR-gamma overexpression protect mitochondrial membrane potential and prevent apoptosis by upregulating anti-apoptotic Bcl-2 family proteins.
To determine the involvement of peroxisome proliferator-activated receptor-gamma (PPAR-gamma) in cytoprotection, we subjected N2-A cells to oxygen-glucose deprivation followed by reoxygenation (H-R). Following H-R insults, H(2)O(2) production was increased while cell viability declined, which was accompanied by loss of mitochondrial membrane potential (MMP), cytochrome c release, caspases 9 and 3 activation, poly(ADP-ribose)polymerase (PARP) cleavage and apoptosis. Rosiglitazone up to 5 microM protected cell viability, normalized MMP, and prevented apoptotic signals. The protective effect of rosiglitazone was abrogated by GW9662, a PPAR-gamma antagonist, or a specific PPAR-gamma small interference RNA (siRNA) but not a control scRNA. PPAR-gamma overexpression alone was effective in maintaining MMP and preventing apoptosis and its protective effect was also abrogated by PPAR-gamma siRNA or GW9662. To elucidate the mechanism by which PPAR-gamma protects MMP and prevents apoptosis, we analyzed Bcl-2, Bcl-xl, and phosphorylated Bad (p-Bad). H-R suppressed them. Rosiglitazone or PPAR-gamma overexpression restored them via PPAR-gamma. Rosiglitazone or PPAR-gamma overexpression preserved phosphorylated Akt and 3-phosphoinositide-dependent kinase-1 (PDK-1) in a PPAR-gamma dependent manner. These results indicate that ligand-activated PPAR-gamma protects N2-A cells against H-R damage by enhancing Bcl-2/Bcl-xl and maintaining p-Bad via preservation of p-Akt.
Wu
Jui-Sheng
JS
Graduate Institute of Life Sciences, National Defense Medical Center; Taipei, Taiwan.
Lin
Teng-Nan
TN
Wu
Kenneth K
KK
D064413:3-Phosphoinositide-Dependent Protein Kinases; D000813:Anilides / Q000494:pharmacology; D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D053148:Caspase 3 / Q000378:metabolism; D053453:Caspase 9 / Q000378:metabolism; D015687:Cell Hypoxia; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D045304:Cytochromes c / Q000378:metabolism; D019610:Cytoprotection; D004305:Dose-Response Relationship, Drug; D005947:Glucose / Q000172:deficiency; D006861:Hydrogen Peroxide / Q000378:metabolism; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects*; D051379:Mice; D008928:Mitochondria / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D009447:Neuroblastoma / Q000378:metabolism / Q000473:pathology; D047495:PPAR gamma / Q000819:agonists* / Q000235:genetics / Q000378:metabolism; D010766:Phosphorylation; D011065:Poly(ADP-ribose) Polymerases / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism*; D034622:RNA Interference; D034741:RNA, Small Interfering; D015427:Reperfusion Injury / Q000378:metabolism / Q000473:pathology / Q000517:prevention & control*; D000077154:Rosiglitazone; D045162:Thiazolidinediones / Q000494:pharmacology*; D013997:Time Factors; D014162:Transfection; D015854:Up-Regulation; D051025:bcl-Associated Death Protein / Q000378:metabolism; D051020:bcl-X Protein / Q000378:metabolism
C457499:2-chloro-5-nitrobenzanilide; D000813:Anilides; C494820:Bad protein, mouse; C494812:Bcl2l1 protein, mouse; D047495:PPAR gamma; D019253:Proto-Oncogene Proteins c-bcl-2; D034741:RNA, Small Interfering; D045162:Thiazolidinediones; D051025:bcl-Associated Death Protein; D051020:bcl-X Protein; D000077154:Rosiglitazone; D045304:Cytochromes c; D006861:Hydrogen Peroxide; D011065:Poly(ADP-ribose) Polymerases; D064413:3-Phosphoinositide-Dependent Protein Kinases; D017346:Protein Serine-Threonine Kinases; D051057:Proto-Oncogene Proteins c-akt; C505409:Casp3 protein, mouse; C506434:Casp9 protein, mouse; D053148:Caspase 3; D053453:Caspase 9; D005947:Glucose