Diazoxide postconditioning induces mitochondrial protein S-nitrosylation and a redox-sensitive mitochondrial phosphorylation/translocation of RISK elements: no role for SAFE.

摘要: Postconditioning (PostC) can be obtained either with brief cycles of ischemia/reperfusion (I-PostC) or a direct targeting mitochondria Diazoxide (pharmacological PostC, P-PostC). I-PostC may induce the activation RISK and SAFE pathways favor nitric oxide production S-Nitrosylation proteins redox signaling. It is not clear whether lead to similar effects. We compared effects P-PostC on (a) kinases RISK- pathway, (b) mitochondrial (c) reduction death signals (PKCδ, cleaved caspase-3 Beclin-1) in cytosolic fractions. Isolated rat hearts underwent (1) perfusion without ischemia (Sham), (2) (30-min plus 2-h reperfusion), (3) (5 intermittent 10-s reperfusion immediately after 30-min ischemia), (4) (Diazoxide 30 μM first 3-min reperfusion) (5) I-PostC + MPG P-PostC + MPG (MPG, 2-mercaptopropionylglycine 300 μM). Using Western blot biotin switch assay, we found that induced sensible phosphorylation/translocation Akt, ERK1/2 GSK3β into mitochondria, but phospho-STAT3, which was translocated by only. Either increased S-Nitrosylated (e.g., VDAC) reduced levels phospho-PKCδ, Beclin-1. Therefore, activates pathway via signaling, favors discrete protein S-Nitrosylation, including VDAC decreases death. Intriguingly, phospho-STAT3 translocation I-PostC, P-PostC, thus suggesting redox-independent mechanism pathway.