Transmembrane protein 166 regulates autophagic and apoptotic activities following focal cerebral ischemic injury in rats.
Transmembrane protein 166 (TMEM166) is a lysosomal/endoplasmic reticulum-associated protein found in various species where it acts as a regulator of programmed cell death, mediating both autophagy and apoptosis. In the present study, we investigated the role of TMEM166 following MCAO injury in rats to determine whether the structural damages following injury were orchestrated in part by TMEM166. One hundred and fifty six male Sprague-Dawley rats were randomly divided into 4 groups: Sham, MCAO, MCAO+control siRNA, MCAO+TMEM166 siRNA. Outcomes were measured including mortality rate, brain edema, BBB disruption, and neurobehavioral testing. Western blotting techniques measured the expression of key pro-autophagic and apoptotic proteins such as TMEM166, Beclin-1, cleaved casepase-3 and Bcl-2/Bax. The study found that TMEM166 siRNA treatment significantly reduced the mortality rate, cerebral edema, neurobehavioral deficits, and BBB disruption as measured by Evan's blue assay following MCAO injury. Immunohistochemical staining and western blotting analysis demonstrated an increased expressions of TMEM166, Beclin-1, LC3, cleaved casepase-3 and Bcl-2/Bax in the infarcted areas. This study suggests that TMEM166 induces autophagy and apoptosis may in fact play a significant role in cell death following MCAO injury and its mediation may be through the crosstalk of Bcl-2. By blocking the activity of TMEM166 using siRNA, we were able to prevent the cell loss that occured following cerebral ischemia injury. This translated into a preservation of functional integrity and an improvement in mortality.
Department of Anatomy and Histology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, China.
Li
L
Li
Nikan H
NH
Khatibi
Qin
Q
Hu
Junhao
J
Yan
Chunhua
C
Chen
Jingyan
J
Han
Dalong
D
Ma
Yinyu
Y
Chen
Changman
C
Zhou
D000818:Animals; D017209:Apoptosis / Q000502:physiology*; D051017:Apoptosis Regulatory Proteins / Q000378:metabolism; D001343:Autophagy / Q000502:physiology*; D000071186:Beclin-1; D001812:Blood-Brain Barrier / Q000503:physiopathology; D001929:Brain Edema / Q000209:etiology; D004195:Disease Models, Animal; D005786:Gene Expression Regulation / Q000187:drug effects / Q000502:physiology*; D005904:Glial Fibrillary Acidic Protein / Q000378:metabolism; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D020287:In Situ Nick-End Labeling; D020244:Infarction, Middle Cerebral Artery / Q000188:drug therapy / Q000473:pathology* / Q000503:physiopathology*; D008297:Male; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D008869:Microtubule-Associated Proteins / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D034741:RNA, Small Interfering / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D013778:Tetrazolium Salts; D013997:Time Factors; D014161:Transduction, Genetic
D051017:Apoptosis Regulatory Proteins; D000071186:Beclin-1; D005904:Glial Fibrillary Acidic Protein; D049452:Green Fluorescent Proteins; D008565:Membrane Proteins; D008869:Microtubule-Associated Proteins; D012333:RNA, Messenger; D034741:RNA, Small Interfering; D013778:Tetrazolium Salts; C512829:Becn1 protein, rat; C526109:Anxa3 protein, rat; C489787:MAP2 protein, rat; C009591:triphenyltetrazolium