title: Protective effect of autophagy inhibition on ischemia-reperfusion-induced injury of N2a cells.
abstract: Autophagy is a conserved and programmed catabolic process that degrades damaged proteins and organelles. But the underlying mechanism and functions of autophagy in the ischemia-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/class III PI3K) and LC-3II (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 p70S6K and mTOR which are involved in autophagy regulation showed delayed inactivation after reperfusion. Administration of 3-methyladenine (3MA), an inhibitor of class III PI3K, abolished autophagy during reperfusion, 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 decline 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 complex-dependent and mTORC1-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.
authors: Emergency Department, Wuhan General Hospital of Guanzhou Military Command, Wuhan, 430070, China.
authors: Zhong-Qiang
authors: ZQ
authors: Wang
authors: Department of Biochemistry and Molecular Biology, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China.
authors: Yi
authors: Y
authors: Yang
authors: Department of Biochemistry and Molecular Biology, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China.
authors: Tao
authors: T
authors: Lu
authors: Department of Biochemistry and Molecular Biology, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China.
authors: Pan
authors: P
authors: Luo
authors: Department of Biochemistry and Molecular Biology, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China.
authors: Jin
authors: J
authors: Li
authors: Department of Biochemistry and Molecular Biology, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China.
authors: Jun-Ping
authors: JP
authors: Wu
authors: Emergency Department, Wuhan General Hospital of Guanzhou Military Command, Wuhan, 430070, China.
authors: Zhong-Zhi
authors: ZZ
authors: Tang
authors: Emergency Department, Wuhan General Hospital of Guanzhou Military Command, Wuhan, 430070, China.
authors: Qi-Ping
authors: QP
authors: Lu
authors: Department of Biochemistry and Molecular Biology, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China. duanqhwz@hotmail.com.
authors: Qiu-Hong
authors: QH
authors: Duan
mesh_terms: D000225:Adenine / Q000031:analogs & derivatives / Q000494:pharmacology; D000818:Animals; D051017:Apoptosis Regulatory Proteins / Q000235:genetics / Q000378:metabolism; D001343:Autophagy; D000071186:Beclin-1; D045744:Cell Line, Tumor; D002470:Cell Survival; D000076222:Mechanistic Target of Rapamycin Complex 1; D051379:Mice; D008928:Mitochondria / Q000378:metabolism; D046912:Multiprotein Complexes / Q000037:antagonists & inhibitors / Q000378:metabolism; D009474:Neurons / Q000187:drug effects / Q000378:metabolism*; D018696:Neuroprotective Agents / Q000494:pharmacology; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D000081082:Phosphoinositide-3 Kinase Inhibitors; D015427:Reperfusion Injury / Q000378:metabolism*; D020123:Sirolimus / Q000494:pharmacology; D058570:TOR Serine-Threonine Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism
chemical_list: D000225:Adenine; D051017:Apoptosis Regulatory Proteins; D000071186:Beclin-1; D000076222:Mechanistic Target of Rapamycin Complex 1; D046912:Multiprotein Complexes; D018696:Neuroprotective Agents; D019869:Phosphatidylinositol 3-Kinases; D000081082:Phosphoinositide-3 Kinase Inhibitors; D020123:Sirolimus; D058570:TOR Serine-Threonine Kinases; C115010:Becn1 protein, mouse; C025946:3-methyladenine