Resin-assisted capture methods show that S-nitrosylation exerts cardioprotection during ischemia/reperfusion injury by directly reducing cysteine oxidation

Tuesday, October 25, 2011 — Poster Session II
Noon – 2:00 p.m.	Natcher Conference Center	NHLBI	OXIDSTRESS-6

* FARE Award Winner

Authors

• MJ Kohr
• J Sun
• A Aponte
• G Wang
• M Gucek
• C Steenbergen
• E Murphy

Abstract

Ischemic preconditioning (IPC) is a protective mechanism of the heart that reduces damage sustained from prolonged periods of ischemia and has been shown to involve redox signaling. S-nitrosylation (SNO) is a reversible, thiol-based redox modification that is greatly increased following myocardial IPC and is thought to play an important role in cardioprotection, in part, by modulating enzyme activity. SNO may also provide cardioprotection by reducing the irreversible cysteine oxidation that occurs via the formation of reactive oxygen species (ROS) during ischemia/reperfusion (IR) injury. In order to test this hypothesis, we developed a method to identify SNO and oxidation sites using resin-assisted capture (SNO-RAC and Ox-RAC). Langendorff perfused hearts were subjected to various perfusion protocols (control, IPC, IR, IPC-IR) and homogenized. Each sample was divided into two equal aliquots, and subjected to the SNO-RAC and Ox-RAC procedures. With IPC, we identified 31 different SNO proteins, 27 of which showed a significant increase in SNO compared to baseline. Interestingly, of these proteins, 76% showed a significant decrease in oxidation or no oxidation following ischemia and early reperfusion (IPC-IR) compared to IR alone. These results support the hypothesis that SNO provides cardioprotection by shielding cysteine residues from ROS-induced oxidation during IR injury.

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