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Maintenance of glutathione homeostasis by NRF2‐dependent regulation of glutathione reductase during cigarette smoke‐induced oxidative stress
Author(s) -
Ling Guoyu,
Harvey Christopher J,
Thimmulappa Rajesh K,
Singh Anju,
Biswal Shyam
Publication year - 2008
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.22.1_supplement.1122.18
Subject(s) - glutathione , oxidative stress , buthionine sulfoximine , chemistry , glutathione reductase , biochemistry , glutathione peroxidase , enzyme
NRF2, a transcription factor, protects from oxidative stress through maintenance of the redox status which is largely mediated through changes in intracellular GSH levels. Oxidative stress leads to oxidation of GSH, which is then reduced back to GSH by glutathione reductase (GSR). The present study was designed to investigate the role of NRF2 in GSR induction and GSH homeostasis during smoke‐induced oxidative stress. Wild type and NRF2 deficient (NRF2−/−) mice and their embryonic fibroblasts were exposed to acute cigarette smoke (CS) and CS extract (CSE) respectively. Induction of GSR, proliferation, and oxidized/reduced glutathione was measured. Exposure to either CS or CSE resulted in increased GSR mRNA and protein levels in mice and in cell culture. Induction of GSR was dependent on NRF2. In mouse embryonic fibroblasts, inhibition of GSH synthesis, by buthionine sulfoxide (BSO), an inhibitor of glutathione synthetase, did not affect cell proliferation. However, inhibition of GSR, using 1,3‐bis(2‐chloroethyl)‐1‐nitroso‐urea (BCNU), reduced cell proliferation and resulted in accumulation of oxidized glutathione. Transient transfection studies, using reporter constructs revealed one functional antioxidant response element in mouse GSR promoter. We conclude that Nrf2 dependent regeneration of glutathione by GSR plays a critical role in protection against cigarette smoke induced oxidative stress.