Effects of Protein kinase C Modulators on the Ischemic Damage of PC12 Cell

Chung, Jin Young; Lee, Sung Hoon; Kim, Yongsook; Cho, In Chul; Lee, Kee Young

Abstract

Ischemia-induced cellular responses are now major concern over various medical fields such as organ transplantation, brain apoplexy, and coronary arterial diseases, etc. PKC pathway, a major component of signal transductions, may play in the modulation of neuronal ischemic damage. The purpose of this study was to clarify the PKC action mode involving responses against ischemia in PC12 cell which has neuronal characteristics. The effects of PKC activators (phorbol 12-myristate 13-acetate, etc.), and inhibitors(staurosporine, etc.), CaMK-II inhibitor(KN62), and anti-oxidants(trolox, etc.) on 6 hour ischemic insult in PC12 cells were checked. PMA, KN62 and trolox attenuated ischemia-induced cell injury but staurosporine aggravated the cell damage. Both PMA and trolox reduced lipid peroxidation whereas KN62 increased it. In immunoblottings, the amounts of PKC-alpha, delta and epsilon were significantly decreased, especially that of PKC-alpha was almost lost 6 hour after ischemia, while the expression level of PKC-zeta was not significantly changed. PMA down-regulated PKC-alpha, delta and epsilon in both normoxia and ischemia, but trolox treatment during ischemic insult did not alter the PKC down-regulation pattern. PKC activation protects PC12 cell damage from ischemic insult, and this protective effect may result the interaction between PKC pathway and anti-oxidation mechanism whereas the effect of CaMK-II on ischemic PC12 cells may mediate the pathway independent to anti-oxidation mechanism.