Effect of Arachidonic Acid Cytochrome P450 Epoxygenase on Bcl-2 Expression， Capase-3 and MAPK Activity in Apoptotic Endothelial Cells Induced by TNF-α

Abstract: Endothelium-derived hyperpolarizing factor (EHDF) may protect endothelial cells against apoptosis induced by TNF-α， the purpose of the present study was to investigate the effects of endogenous EDHF produced by cytochrome P450 (CYP) epoxygenases transfection on Bcl-2 levels， capase-3 activity and the phosphorylation of MAPK in apoptotic endothelial cells induced by TNF-α. Three or four passages of cultured bovine aortic endothelial cells (BAECs) were transfected with CYPBM₃·F87V， CYP2C11OR， CYP2J2 or the empty vector (pCB₆). Twenty-four hours later transfected cells were incubated with TNF-α for appropriate time， the Bcl-2 levels and MAPK phosphorylation were detected by Western blot analysis， and capase-3 activity was examined by using DEVD-p-nitroanilide as a substrate. TNF-α decreased Bcl-2 protein level in a time-dependent manner and increased significantly caspase-3 activity. Transfection of BAECs with epoxygenases prevented the decrease of Bcl-2 protein and caspase-3 activation induced by TNF-α compared with controls. Incubation of BAECs with TNF-α induced a marked dephosphorylation of MAPK in a time-dependent manner. Transfection with epoxygenases increased the phosphorylation levels of MAPK at all examined time points. The present study demonstrates that transfection of CYP epoxygenases may protect endothelial cells and inhibit endothelial apoptosis by increasing the phosphorylation level of ERK1/2， preventing both degradation of anti-apoptotic protein Bcl-2 and activation of caspase-3 induced by TNF-α.

CSTR: 32200.14.cjcb.2007.03.0020