PMID- 17220176 OWN - NLM STAT- MEDLINE DCOM- 20070802 LR - 20211203 IS - 0363-6135 (Print) IS - 0363-6135 (Linking) VI - 292 IP - 6 DP - 2007 Jun TI - Rho kinase activation plays a major role as a mediator of irreversible injury in reperfused myocardium. PG - H2598-606 AB - Intracellular signal transduction events in reperfusion following ischemia influence myocardial infarct development. Here we investigate the role of Rho kinase (ROCK) activation as a specific injury signal during reperfusion via attenuation of the reperfusion injury salvage kinase (RISK) pathway phosphatidylinositol 3-kinase (PI3K)/Akt/endothelial nitric oxide (NO) synthase (eNOS). Rat isolated hearts underwent 35 min of left coronary artery occlusion and 120 min of reperfusion. Phosphorylation of the ROCK substrate protein complex ezrin-radixin-moesin, assessed by immunoblotting and immunofluorescence, was used as a marker of ROCK activation. Infarct size was determined by tetrazolium staining, and terminal dUTP nick-end labeling (TUNEL) positivity was used as an index of apoptosis. The ROCK inhibitors fasudil or Y-27632 given 10 min before ischemia until 10 min after reperfusion reduced infarct size (control, 34.1 +/- 3.8%; 5 microM fasudil, 18.2 +/- 3.1%; 0.3 microM Y-27632, 19.4 +/- 4.4%; 5 microM Y-27632, 9.2 +/- 2.9%). When 5 microM Y-27632 was targeted specifically during early reperfusion, robust infarct limitation was observed (14.2 +/- 2.6% vs. control 33.4 +/- 4.4%, P<0.01). The protective action of Y-27632 given at reperfusion was attenuated by wortmannin (29.2 +/- 6.1%) and N(omega)-nitro-L-arginine methyl ester (30.4 +/- 5.7%), confirming a protective mechanism involving PI3K/Akt/NO. Ezrin-radixin-moesin phosphorylation in risk zone myocardium confirmed early and sustained ROCK activation during reperfusion and its inhibition by Y-27632. Inhibition of ROCK activation at reperfusion reduced the proportion of TUNEL-positive nuclei in the infarcted region. In conclusion, ROCK activation occurs specifically during early reperfusion. Inhibition of ROCK at reperfusion onset limits infarct size through an Akt/eNOS-dependent mechanism, suggesting that ROCK activation at reperfusion may be deleterious through suppression of the RISK pathway. FAU - Hamid, Shabaz A AU - Hamid SA AD - Royal Veterinary College, University of London, London, UK. FAU - Bower, Hugo S AU - Bower HS FAU - Baxter, Gary F AU - Baxter GF LA - eng PT - Journal Article PT - Research Support, Non-U.S. Gov't DEP - 20070112 PL - United States TA - Am J Physiol Heart Circ Physiol JT - American journal of physiology. Heart and circulatory physiology JID - 100901228 RN - 0 (Amides) RN - 0 (Androstadienes) RN - 0 (Cardiotonic Agents) RN - 0 (Cytoskeletal Proteins) RN - 0 (Intracellular Signaling Peptides and Proteins) RN - 0 (Membrane Proteins) RN - 0 (Microfilament Proteins) RN - 0 (Multiprotein Complexes) RN - 0 (Phosphoinositide-3 Kinase Inhibitors) RN - 0 (Protein Kinase Inhibitors) RN - 0 (Pyridines) RN - 0 (ezrin) RN - 138381-45-0 (Y 27632) RN - 144131-77-1 (moesin) RN - 144517-21-5 (radixin) RN - 31C4KY9ESH (Nitric Oxide) RN - 84477-87-2 (1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine) RN - EC 1.14.13.39 (Nitric Oxide Synthase Type III) RN - EC 1.14.13.39 (Nos3 protein, rat) RN - EC 2.7.11.1 (Protein Serine-Threonine Kinases) RN - EC 2.7.11.1 (Proto-Oncogene Proteins c-akt) RN - EC 2.7.11.1 (rho-Associated Kinases) RN - Q0CH43PGXS (fasudil) RN - V55S2QJN2X (NG-Nitroarginine Methyl Ester) RN - XVA4O219QW (Wortmannin) SB - IM CIN - Am J Physiol Heart Circ Physiol. 2007 Jun;292(6):H2563-5. PMID: 17308009 MH - 1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine/analogs & derivatives/pharmacology MH - Amides/pharmacology MH - Androstadienes/pharmacology MH - Animals MH - Apoptosis/*drug effects MH - Cardiotonic Agents/*pharmacology/therapeutic use MH - Coronary Circulation/drug effects MH - Cytoskeletal Proteins/metabolism MH - Enzyme Activation MH - In Vitro Techniques MH - Intracellular Signaling Peptides and Proteins/antagonists & inhibitors/*metabolism MH - Male MH - Membrane Proteins/metabolism MH - Microfilament Proteins/metabolism MH - Multiprotein Complexes/metabolism MH - Myocardial Infarction/enzymology/*metabolism/pathology/physiopathology/prevention & control MH - Myocardial Reperfusion Injury/enzymology/*metabolism/pathology/physiopathology/prevention & control MH - Myocardium/enzymology/*metabolism/pathology MH - NG-Nitroarginine Methyl Ester/pharmacology MH - Nitric Oxide/metabolism MH - Nitric Oxide Synthase Type III/antagonists & inhibitors/metabolism MH - Phosphatidylinositol 3-Kinases/metabolism MH - Phosphoinositide-3 Kinase Inhibitors MH - Phosphorylation MH - Protein Kinase Inhibitors/*pharmacology/therapeutic use MH - Protein Serine-Threonine Kinases/antagonists & inhibitors/*metabolism MH - Proto-Oncogene Proteins c-akt/metabolism MH - Pyridines/pharmacology MH - Rats MH - Rats, Sprague-Dawley MH - Signal Transduction/*drug effects MH - Wortmannin MH - rho-Associated Kinases EDAT- 2007/01/16 09:00 MHDA- 2007/08/03 09:00 CRDT- 2007/01/16 09:00 PHST- 2007/01/16 09:00 [pubmed] PHST- 2007/08/03 09:00 [medline] PHST- 2007/01/16 09:00 [entrez] AID - 01393.2006 [pii] AID - 10.1152/ajpheart.01393.2006 [doi] PST - ppublish SO - Am J Physiol Heart Circ Physiol. 2007 Jun;292(6):H2598-606. doi: 10.1152/ajpheart.01393.2006. Epub 2007 Jan 12.