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 Ca(2+)-calmodulin dependent protein kinases (CCDPK) signaling on hydroperoxide (H2O2)-induced apoptosis in cultured bovine aortic endothelial cells (BAEC).

METHODS

Morphologic changes and quantification of apoptotic cells were determined under fluorescence microscope after a 24-h treatment of BAEC by H2O2. Cell viability was determined with MTT method. DNA fragmentation was visualized by agarose gel electrophoresis. The expression of phospho-p38 and phospho-p42/p44 CCDPK was measured by Western blotting.

RESULTS

H2O2 elicited typical apoptotic morphologic changes (chromatic condensation, nucleus fragmentation) and DNA fragmentation. At 100-500 mumol.L-1, incubation of BAEC with H2O2 for 24 h also induced phospho-p38 and phospho-p42/p44 CCDPK expression in a concentration-dependent manner. Interestingly, H2O2-induced apoptosis was markedly increased by preincubation with U0126, a specific p42/p44 CCDPK inhibitor. However, SB203580, a specific p38 CCDPK inhibitor, enhanced the expression of phospho-p42/p44 CCDPK induced by H2O2, but had no effect on BAEC 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.