Peroxynitrite induces HO-1 expression via PI3K/Akt-dependent activation of NF-E2-related factor 2 in PC12 cells.
Peroxynitrite is a strong oxidant produced by rapid interaction between superoxide anion and nitric oxide radicals and induces oxidative stress and cell death. Treatment of PC12 cells with 3-morpholinosydnonimine (SIN-1), a generator of peroxynitrite, induced the expression of heme oxygenase-1 (HO-1), an antioxidant cytoprotective enzyme. Inhibition of the HO activity by zinc protoporphyrin IX or knockdown of HO-1 gene expression with siRNA exacerbated the SIN-1-induced apoptosis. After SIN-1 treatment, there was a time-related increase in nuclear localization and subsequent binding of NF-E2-related factor 2 (Nrf2) to the antioxidant-responsive element (ARE). Transfection of PC12 cells with dominant-negative Nrf2 abolished the SIN-1-induced increase in Nrf2-ARE binding and subsequent upregulation of HO-1 expression, leading to enhanced cell death. Upon exposure of PC12 cells to SIN-1, the phosphatidylinositol 3-kinase (PI3K) activity was increased in a time-dependent manner. Pretreatment of cells with LY294002, a pharmacologic inhibitor of PI3K or transfection with the kinase-dead mutant Akt abrogated the SIN-1-induced Nrf2 activation and HO-1 expression. Taken together, these results suggest that peroxynitrite activates Nrf2 via PI3K/Akt signaling and enhances Nrf2-ARE binding, which leads to upregulation of HO-1 expression. The SIN-1-induced HO-1 upregulation may confer the adaptive survival response against nitrosative stress.
Li
Mei-Hua
MH
National Research Laboratory, College of Pharmacy, Seoul National University, Shinlim-dong, Kwanak-ku, Seoul 151-742, South Korea.
Cha
Young-Nam
YN
Surh
Young-Joon
YJ
D000818:Animals; D004789:Enzyme Activation; D005786:Gene Expression Regulation / Q000187:drug effects; D051547:Heme Oxygenase-1 / Q000096:biosynthesis*; D008564:Membrane Potentials; D008981:Molsidomine / Q000031:analogs & derivatives / Q000494:pharmacology; D051267:NF-E2-Related Factor 2 / Q000378:metabolism*; D009687:Nuclear Proteins / Q000378:metabolism; D016716:PC12 Cells; D030421:Peroxynitrous Acid / Q000378:metabolism*; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism*; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism*; D051381:Rats
D051267:NF-E2-Related Factor 2; D009687:Nuclear Proteins; D030421:Peroxynitrous Acid; C002385:linsidomine; D008981:Molsidomine; D051547:Heme Oxygenase-1; D019869:Phosphatidylinositol 3-Kinases; D051057:Proto-Oncogene Proteins c-akt