title: Additive protection of the ischemic heart ex vivo by combined treatment with delta-protein kinase C inhibitor and epsilon-protein kinase C activator.
abstract: BACKGROUND
  Protein kinase C (PKC) plays a major role in cardioprotection from ischemia/reperfusion injury. Using an HIV-1 Tat protein-derived peptide to mediate rapid and efficient transmembrane delivery of peptide regulators of PKC translocation and function, we examined the cardioprotective effect of selective delta-PKC inhibitor (deltaV1-1) and epsilon-PKC activator (psi(epsilon)RACK) peptides for ischemia/reperfusion damage in isolated perfused rat hearts. Furthermore, we examined the protective effects of these PKC isozymes in isolated perfused hearts subjected to ischemia/reperfusion damage using transgenic mice expressing these peptides specifically in their cardiomyocytes.
  
  
  RESULTS
  In isolated perfused rat hearts, administration of deltaV1-1 but not psi(epsilon)RACK during reperfusion improved cardiac function and decreased creatine phosphokinase release. In contrast, pretreatment with psi(epsilon)RACK but not deltaV1-1, followed by a 10-minute washout before ischemia/reperfusion, also improved cardiac function and decreased creatine phosphokinase release. Furthermore, administration of psi(epsilon)RACK before ischemia followed by deltaV1-1 during reperfusion only conferred greater cardioprotective effects than that obtained by each peptide treatment alone. Both the delta-PKC inhibitor and epsilon-PKC activator conferred cardioprotection against ischemia/reperfusion injury in transgenic mice expressing these peptides in the heart, and coexpression of both peptides conferred greater cardioprotective effects than that obtained by the expression of each peptide alone.
  
  
  CONCLUSIONS
  delta-PKC inhibitor prevents reperfusion injury, and epsilon-PKC activator mimics ischemic preconditioning. Furthermore, treatment with both peptides confers additive cardioprotective effects. Therefore, these peptides mediate cardioprotection by regulating ischemia/reperfusion damage at distinct time points.
authors.affiliation: Department of Molecular Pharmacology, Stanford University School of Medicine, Stanford, Calif 94305-5174, USA.
authors.forename: Koichi
authors.initials: K
authors.lastname: Inagaki
authors.forename: Harvey S
authors.initials: HS
authors.lastname: Hahn
authors.forename: Gerald W
authors.initials: GW
authors.lastname: Dorn
authors.forename: Daria
authors.initials: D
authors.lastname: Mochly-Rosen
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002316:Cardiotonic Agents / Q000494:pharmacology*; D004357:Drug Synergism; D004359:Drug Therapy, Combination; D020536:Enzyme Activators / Q000494:pharmacology*; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D006321:Heart / Q000187:drug effects*; D066298:In Vitro Techniques; D019157:Ischemic Preconditioning, Myocardial / Q000379:methods; D007527:Isoenzymes / Q000187:drug effects; D051379:Mice; D008822:Mice, Transgenic; D008969:Molecular Sequence Data; D017202:Myocardial Ischemia / Q000188:drug therapy*; D009842:Oligopeptides / Q000096:biosynthesis / Q000235:genetics / Q000494:pharmacology; D010455:Peptides / Q000235:genetics / Q000378:metabolism / Q000494:pharmacology; D010477:Perfusion; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000187:drug effects; D051745:Protein Kinase C-delta; D051744:Protein Kinase C-epsilon; D051381:Rats; D017208:Rats, Wistar; D015427:Reperfusion Injury / Q000517:prevention & control
chemical_list: D002316:Cardiotonic Agents; D020536:Enzyme Activators; D004791:Enzyme Inhibitors; C477271:His-Asp-Ala-Pro-Ile-Gly-Tyr-Asp; D007527:Isoenzymes; D009842:Oligopeptides; D010455:Peptides; C477270:Ser-Phe-Asn-Ser-Tyr-Glu-Leu-Gly-Glu-Ser-Leu; C497259:Prkcd protein, mouse; C497260:Prkcd protein, rat; C497256:Prkce protein, mouse; C497257:Prkce protein, rat; D011493:Protein Kinase C; D051745:Protein Kinase C-delta; D051744:Protein Kinase C-epsilon