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

Abstract

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.

Puerarin attenuates locomotor and cognitive deficits as well as hippocampal neuronal injury through the PI3K/Akt1/GSK-3β signaling pathway in an in vivo model of cerebral ischemia

“…Ischemia/Reperfusion triggers intrinsic and extrinsic pathways of apoptosis [ 28 ]. Apoptosis contains three different signaling pathways: mitochondria-dependent, endoplasmic reticulum (ER)-dependent, and receptor-dependent pathways [ 29 ].…”

Effects of AQP5 gene silencing on proliferation, migration and apoptosis of human glioma cells through regulating EGFR/ERK/ p38 MAPK signaling pathway

“…Proteins c-IAP1 and c-IAP2 directly inhibit the activity of Caspase-3, Caspase-7 and Caspase-9, thereby inhibiting cell apoptosis [ 41 ]. Additionally, XIAP blocks and Livin inhibits could induce cell apoptosis by inhibiting Caspase and activating the TAK1/JNK1 pathways [ 42 , 43 ]. AQP5 gene silencing might increase apoptosis rates by reducing the levels of these apoptosis-inhibiting proteins.…”

Effects of Different Degrees of Carotid Artery Stenosis on the Expression of XIAP and Smac in the Ischemic Penumbra of Rats with Cerebral Ischemia-Reperfusion

“…22 Smac with increased expression can competitively bind XIAP and the Apaf-1 related apoptosome, so as to relieve the inhibition of caspase-9 and caspase-3 caused by the apoptosome, and to promote apoptosis. 23 Zhang et al 24 found that Caspase9 interacted with XIAP through the transnitrosation reactions in the ischemic penumbra, leading to apoptosis. Siegelin et al 25 and Saito et al 26 also found that Smac synthesis was increased in the hippocampus of mice with focal cerebral I/R and rats with cerebral I/R, indicating that Smac was involved in the process of neuronal death after cerebral ischemia.…”