S-Space Graduate School of Convergence Science and Technology (융합과학기술대학원) Dept. of Molecular and Biopharmaceutical Sciences (분자의학 및 바이오제약학과) Journal Papers (저널논문_분자의학 및 바이오제약학과)
Bcl-2 attenuation of oxidative cell death is associated with up-regulation of gamma-glutamylcysteine ligase via constitutive NF-kappa B activation
- Jang, Jung-Hee; Surh, Young-Joon
- Issue Date
- Journal of Biological Chemistry, Vol.279 No.37, pp.38779-38786
- Oxidative stress induced by reactive oxygen intermediates often causes cell death via apoptosis, which is regulated by many functional genes and their protein products. The evolutionarily conserved protein Bcl-2 blocks apoptosis induced by a wide array of death signals. Despite extensive research, the molecular milieu that characterizes the anti-apoptotic function of Bcl-2 has not been fully clarified. In this work, we have investigated the role of bcl-2 in protecting against oxidative death induced by H2O2 in cultured rat pheochromocytoma PC12 cells. Transfection with the bcl-2 gene rescued PC12 cells from apoptotic death caused by H2O2. Addition of NF-kappaB inhibitors such as pyrrolidine dithiocarbamate and N-tosyl-L-phenylalanine chloromethyl ketone to the medium aggravated oxidative cell death. PC12 cells overexpressing bcl-2 exhibited relatively high constitutive DNA binding and transcriptional activities of NF-kappaB compared with vector-transfected control cells. Western blot analysis and immunocytochemistry revealed that bcl-2-transfected PC12 cells retained a higher level of p65 (the functionally active subunit of NF-kappaB) in the nucleus compared with vector-transfected controls. In addition, sustained activation of ERK1/2 (upstream of NF-kappaB) was observed in bcl-2-overexpressing cells. In contrast, the cytoplasmic inhibitor IkappaBalpha was present in lower amounts in cells overexpressing bcl-2. The ectopic expression of bcl-2 increased the cellular glutathione level and gamma-glutamylcysteine ligase expression, which were attenuated by NF-kappaB inhibitors. These results suggest that NF-kappaB plays a role in bcl-2-mediated protection against H2O2-induced apoptosis in PC12 cells through augmentation of antioxidant capacity.
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