Neuregulin rescues PC12-ErbB4 cells from cell death induced by H2O2 - regulation of reactive oxygen species levels by phosphatidylinositol 3-kinase

Neuregulins (NRGs), a large family of transmembrane polypeptide growth fact ors, mediate various cellular responses depending on the cell type and rece ptor expression. We previously showed that NRG mediates survival of PC12-Er bB4 cells from apoptosis induced by serum deprivation or tumor necrosis fac tor-a treatment. In the present study we show that NRG induces a significan t protective effect from H2O2-induced death. This effect of NRG is mediated by the phosphatidylinositol 3-kinase (PI3K)-signaling pathway since NRG fa iled to rescue cells from H2O2 insult in the presence of the PI3K inhibitor , LY294002. Furthermore, the downstream effector of PI3K, protein kinase B/ AKT, is activated by NRG in the presence of H2O2, and protein kinase B/AKT activation is inhibited by LY294002. In addition, our results demonstrate t hat reactive oxygen species (ROS) elevation induced by H2O2 is inhibited by NRG. LY294002, which blocks NRG-mediated rescue, increases ROS levels. Mor eover, both H2O2-induced ROS elevation and cell death are reduced by expres sion of activated PI3K. These results suggest that PI3K-dependent pathways may regulate toxic levels of ROS generated by oxidative stress.