Preconditioning regulation of bcl‐2 and p66^shc by human NOS1 enhances tolerance to oxidative stress

Abstract

Preconditioning stress induced by a transient ischemia may increase brain tolerance to oxidative stress, and the underlying neuroprotective mechanisms are not well understood. In a series of experiments, we found that endogenous nitric oxide (NO), S-nitrosoglutathione (GSNO), and antioxidants blocked serum deprivation-induced oxidative stress and apoptosis in human neuroblastoma cells. Similar to nuclear redox factor-1 (Ref-1), mRNA of human neuronal nitric oxide synthase (hNOS1) was maximally up-regulated within 2 h after oxidative stress and down-regulated by NO/GSNO and hydroxyl radical (OH) scavenger. A brief preconditioning stress induced by serum deprivation for 2 h caused a delayed increase in the expression of hNOS1 protein and the associated formation of NO and cGMP, which in turn decreased OH generation and stress-related cell death. In addition to inhibiting caspase-3 through a dithiothreitol-sensitive S-nitrosylation process, preconditioning stress concomitantly up-regulated the expression of the anti-apoptotic bcl-2 protein and down-regulated the p66shc adaptor protein. This beneficial cytoprotective process of preconditioning stress is mediated by newly synthesized NO because it can be suppressed by the inhibition of hNOS1 and guanylyl cyclase. Therefore, the constitutive isoform of hNOS1 is dynamically redox-regulated to meet both functional and compensatory demands of NO for gene regulation, antioxidant defense, and tolerance to oxidative stress.

Bcl-2 Overexpression Inhibits Generation of Intracellular Reactive Oxygen Species and Blocks Adriamycin-induced Apoptosis in Bladder Cancer Cells

“…Evidences from in vitro and in vivo studies suggested that Bcl-2 might block the apoptosis through the regulation of cellular antioxidant defense mechanisms and, in this context, had been considered to act as a free radical scavenger (Andoh et al, 2000). For instance, the levels of hydroxyl radicals generated by quinoneproducing agents and 3-nitropropionic acid were lowered in Bcl-2-overexpressing cells compared with the vector-transfected control cells (Luanpitpong et al, 2011;Yin et al, 2012).…”

p66 ShcA Modulates Tissue Response to Hindlimb Ischemia

“…28 Moreover, in dilated cardiomyopathy, which is associated with increased levels of oxidative stress-mediated cell death, p66…”

Cellular response to oxidative stress: Signaling for suicide and survival*

“…Reconstitution of wild type p66 shc expression in these cells increases their sensitivity to hydrogen peroxide, while cells expressing mutant forms of the protein that cannot be serine phosphorylated behave like null cells (Migliaccio et al, 1999). In a different model system, Andoh et al (2000) showed that the downregulation of p66 shc caused by serum starvation and concomitant with an upregulation of the antiapoptotic Bcl-2 was associated with enhanced tolerance to oxidative challenges. Taken together, these data suggest that p66 shc is a crucial component of the apoptotic response to oxidative damage (reviewed in Lithgow and Andersen, 2000;Skulachev, 2000).…”