Rapamycin attenuates mitochondrial dysfunction via activation of mitophagy in experimental ischemic stroke.
Rapamycin has been demonstrated to exhibit neuroprotective functions via the activation of autophagy in a cerebral ischemia model. However, the involvement of mitophagy in this process and its contribution to the protection of mitochondrial function remains unknown. The present study explored the characteristics of mitophagy after cerebral ischemia and the effect of rapamycin on mitochondrial function. Male Sprague-Dawley rats underwent transient middle cerebral artery occlusion (tMCAO). Neurological deficits scores; infarct volumes; mitophagy morphology; and the levels of malondialdehyde (MDA), adenosine triphosphate (ATP) and mitochondrial membrane potentials (Δψm) were examined. The expression of LC3, Beclin-1 and p62 in the mitochondrial fraction combined with transmission electronic microscopy were used to explore mitophagic activity after ischemia. We also blocked autophagosome formation using 3-methyladenine (3-MA) to check the linkage between the mitochondrial protective effect of rapamycin and enhanced mitophagy. We observed that rapamycin significantly enhanced mitophagy, as evidenced by the increase in LC3-II and Beclin-1 expression in the mitochondria and p62 translocation to the mitochondria. Rapamycin reduced infarct volume, improved neurological outcomes and inhibited mitochondrial dysfunction compared with the control animals (p<0.05). However, these protective effects were reversed by 3-methyladenine treatment after rapamycin. The present study indicates that rapamycin treatment attenuates mitochondrial dysfunction following cerebral ischemia, which is linked to enhanced mitophagy.
Department of Neurology, Shanghai Sixth People's Hospital, Shanghai Jiao Tong University, Shanghai 200233, China; Department of Neurology, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200011, China.
Qiang
Q
Li
Department of Neurology, Shanghai Sixth People's Hospital, Shanghai Jiao Tong University, Shanghai 200233, China.
Ting
T
Zhang
Department of Neurology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China; Med-X Research Institute and School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai 200030, China.
Jixian
J
Wang
Med-X Research Institute and School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai 200030, China.
Zhijun
Z
Zhang
Department of Neurology, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200011, China.
Yu
Y
Zhai
Department of Neurology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China; Med-X Research Institute and School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai 200030, China. Electronic address: gyyang0626@gmail.com.
Guo-Yuan
GY
Yang
Department of Neurology, Shanghai Sixth People's Hospital, Shanghai Jiao Tong University, Shanghai 200233, China. Electronic address: sunxj19@gmail.com.
Xiaojiang
X
Sun
D048868:Adaptor Proteins, Signal Transducing / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D051017:Apoptosis Regulatory Proteins / Q000378:metabolism; D001343:Autophagy / Q000187:drug effects; D000071186:Beclin-1; D015153:Blotting, Western; D001921:Brain / Q000098:blood supply / Q000378:metabolism / Q000648:ultrastructure; D002545:Brain Ischemia / Q000150:complications; D007150:Immunohistochemistry; D007166:Immunosuppressive Agents / Q000494:pharmacology; D020244:Infarction, Middle Cerebral Artery / Q000378:metabolism / Q000503:physiopathology / Q000517:prevention & control; D008297:Male; D008315:Malondialdehyde / Q000378:metabolism; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects; D008565:Membrane Proteins / Q000378:metabolism; D046529:Microscopy, Electron, Transmission; D008869:Microtubule-Associated Proteins / Q000378:metabolism; D008928:Mitochondria / Q000187:drug effects* / Q000378:metabolism / Q000502:physiology; D063306:Mitophagy / Q000187:drug effects*; D021381:Protein Transport / Q000187:drug effects; D051381:Rats; D017207:Rats, Sprague-Dawley; D000071456:Sequestosome-1 Protein; D020123:Sirolimus / Q000494:pharmacology*; D020521:Stroke / Q000209:etiology / Q000473:pathology / Q000517:prevention & control*
D048868:Adaptor Proteins, Signal Transducing; D051017:Apoptosis Regulatory Proteins; C491997:BECN1 protein, human; D000071186:Beclin-1; D007166:Immunosuppressive Agents; C477012:MAP1LC3A protein, human; D008565:Membrane Proteins; D008869:Microtubule-Associated Proteins; C099718:SQSTM1 protein, human; D000071456:Sequestosome-1 Protein; D008315:Malondialdehyde; D000255:Adenosine Triphosphate; D020123:Sirolimus
Brain; Ischemia; Mitochondria function; Mitophagy; Rapamycin