Effects of pertussis and cholera toxin on oxidized low density lipoprotein induced apoptosis in cultured bovine aortic endothelial cells / 대한내과학회지

ABSTRACT

OBJECTIVES: Oxidized LDL is thought to play a key role in atherogenesis. Among their wide variety of biological properties, oxidized LDL injures the endothelium as an early event of atherogenesis. However, the mechanisms by which oxidized LDL injures endothelial cells are not definitely known. In order to evaluate the involvement of GTP-binding protein on the mechanism of apoptosis, we studied the effects of pertussis and cholera toxin on oxidized LDL-induced apoptosis in bovine aortic endothelial cells(BAECs). METHODS: Oxidized LDL elicited apoptosis in cultured BAECs as shown by characteristic morphological and biochemical changes. Chromatin condensation and nucleus fragmentation were visualized by using fluorescence microscopy of intact cells staining by acridine orange/ ethidium bromide. DNA fragmentation was quantified by an ELISA with specific antibody for bromodeoxyuridine- labelled DNA fragments and confirmed with DNA ladder formation. RESULTS: Studies using a combination of bacterial toxins which change the function of GTP-binding protein suggest that oxidized LDL-induced apoptosis was regulated by GTP-binding protein. Oxidized LDL-induced apoptosis was not changed by pretreatment of BAECs with pertussis toxin. In contrast, pretreatment with cholera toxin completely prevented the oxidized LDL- induced apoptosis. CONCLUSION: These results show that oxidized LDL induces apoptosis of BAECs and suggest that cholera toxin-sensitive G-proteins are involved in signal transduction of oxidized LDL-induced apoptosis of BAEC.