Phosphorylation of bad by protein Kinase-C activator can attenuate tongue muscle-derived stem cell death caused by oxidative stress

Background: Improving the survival of transplanted cells is a critical issue in the use of stem cell transplantation therapy for cardiovascular disease. Many transplanted cells are lost through apoptosis or necrosis triggered by hypoxia or superoxide. Methods and Results: Tongue muscle-derived Sca-1(+) cells were isolated from the mouse and cultured for 2 weeks and then exposed to hydrogen peroxide (H2O2; 0.2 mM) for 24 h. The extent of cell death by either apoptosis or necrosis was measured by fluorescence-activated cell sorting using annexin V and propidium iodide. The effects of the protein kinase C activator phorbol 12-myristate 13-acetate (10 μM) on H2O2-induced cell death were investigated. Phorbol 12-myristate 13-acetate significantly improved cell survival (49.2 % ± 8.1 % to 64.3 % ± 5.1 %, P < 0.01) while its inhibitor, chelerythrine (1μM), abrogated the effect. The phosphorylation of Bad at serine112 residue was augmented by phorbol 12-myristate 13-acetate; which was inhibited by chelerythrine. Conclusions: Protein kinase C activator is useful to prevent cell death of tongue muscle-derived Sca-1(+) cells through the activation of Bad at serine 112 residue.