Protective Effect of Autophagy Inhibition on Ischemia-reperfusion-induced Injury of N2a Cells  

作　　者：王忠强 杨易 卢涛 罗盼 李婧 吴俊平 唐忠志 卢绮萍 段秋红 

机构地区：[1]Emergency Department,Wuhan General Hospital of Guanzhou Military Command [2]Department of Biochemistry and Molecular Biology,Tongji Medical College,Huazhong University of Science and Technology

出　　处：《Journal of Huazhong University of Science and Technology(Medical Sciences)》2013年第6期810-816,共7页华中科技大学学报（医学英德文版）

基　　金：supported by grants from the Graduate Programs Foundation of Ministry of Education of China(No.20070487101);Postdoctoral Foundation of China(No.20090450216)

摘　　要：Autophagy is a conserved and programmed catabolic process that degrades damaged pro- teins and organelles. But the underlying mechanism and functions of autophagy in the ische- mia-reperfusion （IR）-induced injury are unknown. In this study, we employed simulated IR of N2a cells as an in vitro model of IR injury to the neurons and monitored autophagic processes. It was found that the levels of Beclin-1 （a key molecule of autophay complex, Beclin-1/elass III PI3K） and LC-3 II （an autophagy marker） were remarkably increased with time during the process of ischemia and the process of reperfusion after 90 min of ischemia, while the protein kinases pTOS6K and roTOR which are involved in autophagy regulation showed delayed inactivation after reperfusion. Admini- stration of 3-methyladenine （3MA）, an inhibitor of class III PI3K, abolished autophagy during reper- fusion, while employment of rapamycin, an inhibitor of mTORC1 （normally inducing autophagy）, surprisingly weakened the induction of autophagy during reperfusion. Analyses of mitochondria function by relative cell viability demonstrated that autophagy inhibition by 3-MA attenuated the de- cline of mitochondria function during reperfusion. Our data demonstrated that there were two distinct dynamic patterns of autophagy during IR-induced N2a injury, Beclin-1/class III PI3K com- plex-dependent and mTORCl-dependent. Inhibition of over-autophagy improved cell survival. These suggest that targeting autophagy therapy will be a novel strategy to control IR-induced neuronal damage.Autophagy is a conserved and programmed catabolic process that degrades damaged pro- teins and organelles. But the underlying mechanism and functions of autophagy in the ische- mia-reperfusion （IR）-induced injury are unknown. In this study, we employed simulated IR of N2a cells as an in vitro model of IR injury to the neurons and monitored autophagic processes. It was found that the levels of Beclin-1 （a key molecule of autophay complex, Beclin-1/elass III PI3K） and LC-3 II （an autophagy marker） were remarkably increased with time during the process of ischemia and the process of reperfusion after 90 min of ischemia, while the protein kinases pTOS6K and roTOR which are involved in autophagy regulation showed delayed inactivation after reperfusion. Admini- stration of 3-methyladenine （3MA）, an inhibitor of class III PI3K, abolished autophagy during reper- fusion, while employment of rapamycin, an inhibitor of mTORC1 （normally inducing autophagy）, surprisingly weakened the induction of autophagy during reperfusion. Analyses of mitochondria function by relative cell viability demonstrated that autophagy inhibition by 3-MA attenuated the de- cline of mitochondria function during reperfusion. Our data demonstrated that there were two distinct dynamic patterns of autophagy during IR-induced N2a injury, Beclin-1/class III PI3K com- plex-dependent and mTORCl-dependent. Inhibition of over-autophagy improved cell survival. These suggest that targeting autophagy therapy will be a novel strategy to control IR-induced neuronal damage.

关 键 词：ISCHEMIA/REPERFUSION AUTOPHAGY LC-3 BECLIN-1 mTORC1 3-methyladenine rapamy- cin 

分 类 号：R363[医药卫生—病理学]