Procaspase-9 induces its cleavage by transnitrosylating XIAP via the Thioredoxin system during cerebral ischemia-reperfusion in rats

• Published in: Scientific reports 2016-04, Vol.6 (1), p.24203-24203, Article 24203
• Main Authors: Zhang, Dengyue, Zhao, Ningjun, Ma, Bin, Wang, Yan, Zhang, Gongliang, Yan, Xianliang, Hu, Shuqun, Xu, Tie
• Format: Article
• Language: English
• Subjects: 1-Chloro-2,4-dinitrobenzene; 13/2; 13/95; 42; 42/35; 42/70; 631/45/612/1234; 692/617/375/380/534; 82; 82/29; 82/80; Amino Acid Sequence; Animals; Apoptosis; Apoptosis - genetics; Blotting, Western; Brain Ischemia - genetics; Brain Ischemia - metabolism; CA1 Region, Hippocampal - cytology; CA1 Region, Hippocampal - metabolism; Caspase; Caspase 9 - genetics; Caspase 9 - metabolism; Caspase-3; Cell Line, Tumor; Dinitrochlorobenzene - pharmacology; HEK293 Cells; Hippocampus; Humanities and Social Sciences; Humans; Inhibitor of Apoptosis Proteins - genetics; Inhibitor of Apoptosis Proteins - metabolism; Ischemia; Male; multidisciplinary; Mutation; Neurons - drug effects; Neurons - metabolism; Nitric oxide; Nitric Oxide - metabolism; Oligonucleotides, Antisense - genetics; Oligonucleotides, Antisense - pharmacology; Peptides - pharmacology; Protein Binding - genetics; Rats, Sprague-Dawley; Reperfusion; Reperfusion Injury - genetics; Reperfusion Injury - metabolism; Rodents; Science; Thioredoxin; Thioredoxins - genetics; Thioredoxins - metabolism; XIAP protein
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/srep24203

Transnitrosylation is an important mechanism by which nitric oxide (NO) modulates cell signaling pathways. For instance, SNO-caspase-3 can transnitrosylate the X-linked inhibitor of apoptosis (XIAP) to enhance apoptosis. XIAP is a potent antagonist of caspase apoptotic activity. Decrease in XIAP activity via nitrosylation results in SNO-XIAP-mediated caspase activation. Considering the functional liaison of procaspase-9 and XIAP, we hypothesized that procaspase-9 nitrosylates XIAP directly. Our data confirmed that cerebral ischemia-reperfusion induced XIAP nitrosylation, procaspase-9 denitrosylation and cleavage. Interestingly, the time courses of the nitrosylation of procaspase-9 and XIAP were negatively correlated, which was more prominent after cerebral ischemia-reperfusion, suggesting a direct interaction. The nitrosylation of XIAP, as well as the denitrosylation and cleavage of procaspase-9, were inhibited by DNCB, TrxR1 AS-ODNs, or TAT-AVPY treatment. Meanwhile, DNCB, TrxR1 AS-ODNs, or TAT-AVPY also inhibited the decrease in hippocampal CA1 neurons induced by ischemia-reperfusion in rats. The denitrosylation and cleavage of procaspase-9 induced by OGD/reoxygenation in SH-SY5Y cells were inhibited when cells were co-transfected with wild-type procaspase-9 and XIAP mutant (C449G). These data suggest that cerebral ischemia-reperfusion induces a transnitrosylation from procaspase-9 to XIAP via the Trx system to consequently cause apoptosis. Additionally, Cys325 is a critical S-nitrosylation site of procaspase-9.