Cyclic GMP-dependent protein kinase regulates the expression of thioredoxin and thioredoxin peroxidase-1 during hormesis in response to oxidative stress-induced apoptosis.
Human neuroblastoma cells, SH-SY5Y, contain relatively low levels of thioredoxin (Trx); thus, they serve favorably as a model for studying oxidative stress-induced apoptosis (Andoh, T., Chock, P. B., and Chiueh, C. C. (2001) J. Biol. Chem. 277, 9655-9660). When these neurotrophic cells were subjected to nonlethal 2-h serum deprivation, their neuronal nitric oxide synthase and Trx were up-regulated, and the cells became more tolerant of oxidative stress, indicating that NO may protect cells from serum deprivation-induced apoptosis. Here, the mechanism by which NO exerts its protective effects was investigated. Our results reveal that in SH-SY5Y cells, NO inhibits apoptosis through its ability to activate guanylate cyclase, which in turn activates the cGMP-dependent protein kinase (PKG). The activated PKG is required to protect cells from lipid peroxidation and apoptosis, to inhibit caspase-9 and caspase-3 activation, and to elevate the levels of Trx peroxidase-1 and Trx, which subsequently induces the expression of Bcl-2. Furthermore, active PKG promotes the elevation of c-Jun, phosphorylated MAPK/ERK1/2, and c-Myc, consistent with the notion that PKG enhances the expression of Trx through its c-Myc-, AP-1-, and PEA3-binding motifs. Elevation of Trx and Trx peroxidase-1 and Mn(II)-superoxide dismutase would reduce H(2)O(2) and O(2)(), respectively. Thus, the cytoprotective effect of NO in SH-SY5Y cells appears to proceed via the PKG-mediated pathway, and S-nitrosylation of caspases plays a minimal role.
Andoh
Tsugunobu
T
Laboratory of Biochemistry, NHLBI, National Institutes of Health, Bethesda, Maryland 20892-8012, USA.
Chiueh
Chuang Chin
CC
Chock
P Boon
PB
D000222:Adaptation, Physiological; D017209:Apoptosis; D006152:Cyclic GMP / Q000502:physiology; D017869:Cyclic GMP-Dependent Protein Kinases / Q000502:physiology*; D006162:Guanylate Cyclase / Q000502:physiology; D006801:Humans; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D009363:Neoplasm Proteins; D009569:Nitric Oxide / Q000502:physiology; D019001:Nitric Oxide Synthase / Q000502:physiology; D052248:Nitric Oxide Synthase Type I; D018384:Oxidative Stress; D010544:Peroxidases / Q000096:biosynthesis*; D061105:Peroxiredoxin III; D054464:Peroxiredoxins; D010766:Phosphorylation; D011493:Protein Kinase C / Q000502:physiology; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000096:biosynthesis; D016271:Proto-Oncogene Proteins c-myc / Q000378:metabolism; D013879:Thioredoxins / Q000096:biosynthesis*; D014407:Tumor Cells, Cultured
D009363:Neoplasm Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D016271:Proto-Oncogene Proteins c-myc; D009569:Nitric Oxide; D013879:Thioredoxins; D010544:Peroxidases; C516115:PRDX3 protein, human; D061105:Peroxiredoxin III; D054464:Peroxiredoxins; C496320:NOS1 protein, human; D019001:Nitric Oxide Synthase; D052248:Nitric Oxide Synthase Type I; D017869:Cyclic GMP-Dependent Protein Kinases; D011493:Protein Kinase C; D020928:Mitogen-Activated Protein Kinases; D006162:Guanylate Cyclase; D006152:Cyclic GMP