title: Inhibition of thioredoxin-1 with siRNA exacerbates apoptosis by activating the ASK1-JNK/p38 pathway in brain of a stroke model rats.
abstract: Apoptosis is critical for the development of cerebral ischemia/reperfusion injury. Thioredoxin-1(Trx-1) protein has been reported to have anti-apoptotic effects in a variety of cell types, and it has been implicated in brain injury after middle cerebral artery occlusion (MCAO). Thus, we studied the effects of Trx1 silencing after MCAO in rats and examined whether inhibition of endogenous Trx1 could increase tissue levels of apoptosis. Male Sprague-Dawley rats (N=170) were subjected to 1h of middle cerebral arterial occlusion followed by 24h of reperfusion. Trx1 siRNAs were injected into rat brains 24h prior to MCAO. Then, 24h after MCAO, brains were collected from euthanized rats for investigation. Treatment with Trx1 siRNA significantly increased mortality, behavioral deficits, and cerebral infarction volume and exacerbated neuronal cell apoptotic death after MCAO injury. Western blot revealed increased expression of apoptotic proteins such as P-ASK1, P-JNK, P-p38, cleaved caspase-3 and increased the level of cytochrome c in the cytosolic fraction in the Trx1 siRNA-treated group. Co-immunoprecipitation assay suggested an interaction between Trx1 and ASK1 in normal rat brains and Trx1 siRNA dissociated ASK1-Trx1 binding complex. Our data suggest that Trx1 siRNA increases apoptotic stress-induced ASK1 activation and this represents further evidence that Trx1 is an endogenous anti-apoptotic molecule that diminishes focal cerebral ischemia/reperfusion injury. Its mechanism of action is likely related to attenuation of the ASK1-JNK/p38 signaling pathway.
authors.affiliation: Department of Pathophysiology, Chongqing Medical University, Chongqing, People׳s Republic of China; Institute of Neuroscience, Chongqing Medical University, Chongqing, People׳s Republic of China.
authors.forename: Xiaoying
authors.initials: X
authors.lastname: Wu
authors.affiliation: Department of Pathophysiology, Chongqing Medical University, Chongqing, People׳s Republic of China; Institute of Neuroscience, Chongqing Medical University, Chongqing, People׳s Republic of China.
authors.forename: Lingyu
authors.initials: L
authors.lastname: Li
authors.affiliation: Molecular Medicine and Cancer Research Center, Chongqing Medical University, Chongqing, People׳s Republic of China.
authors.forename: Luyu
authors.initials: L
authors.lastname: Zhang
authors.affiliation: Department of Pathology, Chongqing Medical University, Chongqing, People׳s Republic of China; Institute of Neuroscience, Chongqing Medical University, Chongqing, People׳s Republic of China.
authors.forename: Jingxian
authors.initials: J
authors.lastname: Wu
authors.affiliation: Department of Pathology, Chongqing Medical University, Chongqing, People׳s Republic of China; Institute of Neuroscience, Chongqing Medical University, Chongqing, People׳s Republic of China.
authors.forename: Yunchuan
authors.initials: Y
authors.lastname: Zhou
authors.affiliation: Department of Pathology, Chongqing Medical University, Chongqing, People׳s Republic of China; Institute of Neuroscience, Chongqing Medical University, Chongqing, People׳s Republic of China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Zhou
authors.affiliation: Department of Pathology, Chongqing Medical University, Chongqing, People׳s Republic of China; Institute of Neuroscience, Chongqing Medical University, Chongqing, People׳s Republic of China.
authors.forename: Yong
authors.initials: Y
authors.lastname: Zhao
authors.affiliation: Department of Pathophysiology, Chongqing Medical University, Chongqing, People׳s Republic of China; Institute of Neuroscience, Chongqing Medical University, Chongqing, People׳s Republic of China. Electronic address: zjbingsheng@sina.com.
authors.forename: Jing
authors.initials: J
authors.lastname: Zhao
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000502:physiology*; D001921:Brain / Q000473:pathology / Q000503:physiopathology*; D053148:Caspase 3 / Q000378:metabolism; D045304:Cytochromes c / Q000378:metabolism; D004195:Disease Models, Animal; D020244:Infarction, Middle Cerebral Artery; D048670:MAP Kinase Kinase 4 / Q000378:metabolism; D048848:MAP Kinase Kinase Kinase 5 / Q000378:metabolism; D020935:MAP Kinase Signaling System / Q000502:physiology*; D008297:Male; D012333:RNA, Messenger / Q000378:metabolism; D034741:RNA, Small Interfering / Q000378:metabolism*; D011897:Random Allocation; D017207:Rats, Sprague-Dawley; D020521:Stroke / Q000473:pathology / Q000503:physiopathology*; D013879:Thioredoxins / Q000037:antagonists & inhibitors* / Q000235:genetics; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism
chemical_list: D012333:RNA, Messenger; D034741:RNA, Small Interfering; C495697:Txn1 protein, rat; D013879:Thioredoxins; D045304:Cytochromes c; D048051:p38 Mitogen-Activated Protein Kinases; D048848:MAP Kinase Kinase Kinase 5; C482858:MAP3K5 protein, human; D048670:MAP Kinase Kinase 4; C505410:Casp3 protein, rat; D053148:Caspase 3
keywords: Apoptosis; Apoptosis signal-regulating kinase-1 (ASK1); Cerebral ischemia; Thioredoxin-1; siRNA