Glycoprotein 130 regulates cardiac myocyte survival in doxorubicin-induced apoptosis through phosphatidylinositol 3-kinase/Akt phosphorylation and Bcl-xL/caspase-3 interaction

[摘要] Background-We recently reported that the activation of glycoprotein (gp) 130 by leukemia inhibitory factor (LIF) upregulates Bcl-xL and exerts antiapoptotic effects in cardiac myocytes, In addition, LIF induces activation of phosphatidylinositol (PI) 3-kinase and Akt, which are known to be required for cell survival. However, their regulatory roles in cell death remain unknown. Methods and Results-We investigated the fate of these proteins and the cytoprotective effects of LIF on doxorubicin (DOX)-induced apoptosis in cultured neonatal rat cardiac myocytes. Myocyte apoptosis increased significantly in DOX-treated cells but was significantly reduced by LIF pretreatment, The kinase activities of PI 3-kinase and Akt declined below basal levels but were partially recovered with LIF. Moreover, DOX-induced caspase-3 activation and decrease in Bcl-xL abundance are completely inhibited by LIF and caspase inhibitor, LIF phosphorylates Bad through PI 3-kinase and reduces the heterodimerization of Bad with Bcl-xL. Adenovirus transfer of the constitutively active form of Akt to cardiac myocytes restored cardiac myocyte survival after DOX treatment. Conversely, the dominant-negative form of Akt inhibited LIF-induced increase in cell viability and suppression of caspase-9 activation. Conclusions-Activation of gp 130 inhibits DOX-induced cell death in cardiac myocytes, resulting in the restoration of PI 3-kinase/Akt activities and in the inactivation of caspase-3, leading to facilitation of the protective function of Bcl-xL.

[效力级别]  Proceedings Paper

[关键词] PROTEIN-KINASE;CELL-DEATH;GROWTH-FACTOR;HEART-FAILURE;HL-60 CELLS;BCL-X(L);BCL-2;OVEREXPRESSION;STRESS;AKT