Abstract P270: Resin-Assisted Capture Reveals Unique Targets of Oxidation in Ischemic Preconditioning
Proper maintenance of cellular thiol redox status is critical in the regulation of many processes that dictate normal myocardial function. Cell death signaling, in particular, is especially susceptible to alterations in thiol redox state. Myocardial ischemic preconditioning (IPC) is a redox sensitive process that is thought to provide protection from ischemia-reperfusion (IR) injury, in part, via reversible oxidative signaling. Protein S-nitrosylation (SNO) is a reversible, thiol-based modification that we and others have shown to provide cardioprotection by modulating the activity of target proteins and by shielding cysteine residues from irreversible oxidation. Additional thiol-based modifications are also thought to play an important role in cardioprotection, and these include disulfide bridges and glutathiolation. Therefore, it is of interest to identify these redox sensitive targets that are unique to IPC. Langendorff perfused mouse hearts were subjected to various perfusion protocols (control, IPC, IR, IPC-IR) and homogenized. Specific sites of oxidation were identified using oxidation-resin assisted capture (Ox-RAC) with mass spectrometry. Consistent with a role for oxidative signaling in cardioprotection, Ox-RAC analysis identified 56 proteins that were oxidized with IPC, but not IR or IPC-IR. These proteins are likely to be reversibly oxidized, as evidenced by the fact that they are oxidized with IPC, but are no longer oxidized following reperfusion (IPC-IR). These proteins may represent important targets in cardioprotective signaling and include F-actin-capping protein β, Egl nine homolog 1, and numerous members of the heat shock family (HSP60, HSP70, HSP90β). Heat shock proteins are important in the cellular stress response and have been shown to play an important role in cardioprotection. Pathway analysis also revealed that more than 30% (19 of 56) of the proteins uniquely oxidized following IPC were involved with cell death pathways. These proteins include Aminoacyl tRNA synthase complex-interacting multifunctional protein 1, Charged multivesicular body protein 5, and Lamin-A/C. These results indicate that the cardioprotective effects of IPC may occur, in part, through the reversible oxidation of key protein targets.
- © 2011 by American Heart Association, Inc.