Local delivery of PKCepsilon-activating peptide mimics ischemic preconditioning in aged hearts through GSK-3beta but not F1-ATPase inactivation.
In adult heart, selective PKCepsilon activation limits ischemia (I)-reperfusion (R) damage and mimics the protection associated with ischemic preconditioning. We sought to determine whether local delivery of PKCepsilon activator peptide psiepsilon-receptor for activated C-kinase (psiepsilon-RACK) is sufficient to produce a similarly protected phenotype in aged hearts. Langendorff-perfused hearts isolated from adult (5 mo; n = 9) and aged (24 mo; n = 9) male Fisher 344 rats were perfused with psiepsilon-RACK conjugated to Tat (500 nM) or Tat only (500 nM) for 10 min before global 31-min ischemia. Western blotting was used to measure mitochondrial targeting of PKCepsilon, PKCdelta, phospho (p)-GSK-3beta (Ser(9)) and GSK-3beta in hearts snap-frozen during I. Recovery of left ventricular developed pressure was significantly improved by psiepsilon-RACK (P < 0.01) and infarct size reduced in 24-mo rats vs. age-matched controls (60% vs. 34%; P < 0.01). Mitochondrial PKCepsilon levels were 30% greater during I with psiepsilon-RACK in aged vs. control rats (P < 0.01). Interestingly, mitochondrial GSK-3beta levels were threefold greater in aged vs. adult rats during I, and psiepsilon-RACK prevented this increase (P < 0.01). Mitochondrial p-GSK-3beta levels were also greater in aged rats after psiepsilon-RACK (P < 0.01), and subsequent inhibition of GSK-3beta with SB-216763 (3 muM) before I/R elicited protection similar to that of psiepsilon-RACK (n = 3/group). Mitochondrial proteomic analysis further identified group differences in the F(1)-ATPase beta-subunit, and coimmunoprecipitation studies revealed a novel interaction with PKCepsilon. F(1)-ATPase-PKCepsilon association was affected by psiepsilon-RACK in adult but not aged rats. Our results provide evidence, for the first time, for PKCepsilon-mediated protection in aged rat heart after I/R and suggest a central role for mitochondrial GSK-3beta but not F(1)-ATPase as a potential target of PKCepsilon to limit I/R damage with aging.
Intercollege Program in Physiology, Pennsylvania State University, University Park, Pennsylvania 16802, USA. dhk102@psu.edu
Donna H
DH
Korzick
John C
JC
Kostyak
J Craig
JC
Hunter
Kurt W
KW
Saupe
D000375:Aging / Q000378:metabolism; D000818:Animals; D002316:Cardiotonic Agents / Q000008:administration & dosage / Q000494:pharmacology* / Q000627:therapeutic use; D004789:Enzyme Activation / Q000187:drug effects; D038362:Glycogen Synthase Kinase 3 / Q000378:metabolism*; D000071679:Glycogen Synthase Kinase 3 beta; D006321:Heart / Q000187:drug effects* / Q000503:physiopathology; D066298:In Vitro Techniques; D019194:Ischemic Preconditioning; D008297:Male; D008929:Mitochondria, Heart / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism; D015428:Myocardial Reperfusion Injury / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology / Q000517:prevention & control*; D009206:Myocardium / Q000201:enzymology / Q000378:metabolism* / Q000473:pathology; D009842:Oligopeptides / Q000008:administration & dosage / Q000494:pharmacology* / Q000627:therapeutic use; D010766:Phosphorylation; D051745:Protein Kinase C-delta / Q000378:metabolism; D051744:Protein Kinase C-epsilon / Q000378:metabolism*; D021122:Protein Subunits; D040901:Proteomics; D006180:Proton-Translocating ATPases / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D016277:Ventricular Function, Left / Q000187:drug effects; D017725:Ventricular Pressure / Q000187:drug effects
D002316:Cardiotonic Agents; C477271:His-Asp-Ala-Pro-Ile-Gly-Tyr-Asp; D009842:Oligopeptides; D021122:Protein Subunits; D000071679:Glycogen Synthase Kinase 3 beta; C000605508:Gsk3b protein, rat; D051745:Protein Kinase C-delta; D051744:Protein Kinase C-epsilon; D038362:Glycogen Synthase Kinase 3; D006180:Proton-Translocating ATPases