Effects of p38 and p42/p44 CCDPK signaling on H2O2-induced apoptosis in bovine aortic endothelial cells

AIM: To investigate the effects of p38 and p42/p44 Ca2+-calmodulin dependen t protein kinases (CCDPK) signaling on hydroperoxide (H2O2)-induced apoptos is in cultured bovine aortic endothelial cells (BAEC). METHODS: Morphologic changes and quantification of apoptotic cells were determined under fluore scence microscope after a 24-h treatment of BAEC by H2O2. Cell viability wa s determined with MTT method. DNA fragmentation was visualized by agarose g el electrophoresis. The expression of phospho-p38 and phospho-p42/p44, CCDP K was measured by Western blotting. RESULTS: H2O2 elicited typical apoptoti c morphologic changes (chromatic condensation, nucleus fragmentation) and D NA fragmentation. At 100 - 500 mu mol . L-1, incubation of BAEC with H2O2 f or 24 h also induced phospho-p38 and phospho-p42/p44 CCDPK expression in a concentration-dependent manner. Interestingly, H2O2-induced apoptosis was m arkedly increased by preincubation with U0126, a specific p42/p44 CCDPK inh ibitor. However, SB203580, a specific p38 CCDPK inhibitor, enhanced the exp resssion of phospho-p42/p44 CCDPK induced by H2O2, but had no effect on BAE C survival. CONCLUSION: p42/p44, CCDPK signaling appears to play protective roles in H2O2-induced apoptosis in BAEC, whereas p38 CCDPK is not the main signaling pathway mediating H2O2-induced cellular apoptosis.