title: Role of nitric oxide in regulating aldose reductase activation in the ischemic heart.
abstract: Aldose reductase (AR) catalyzes the reduction of several aldehydes ranging from lipid peroxidation products to glucose. The activity of AR is increased in the ischemic heart due to oxidation of its cysteine residues, but the underlying mechanisms remain unclear. To examine signaling mechanisms regulating AR activation, we studied the role of nitric oxide (NO). Treatment with the NO synthase (NOS) inhibitor, N-nitro-l-arginine methyl ester prevented ischemia-induced AR activation and myocardial sorbitol accumulation in rat hearts subjected to global ischemia ex vivo or coronary ligation in situ, whereas inhibition of inducible NOS and neuronal NOS had no effect. Activation of AR in the ischemic heart was abolished by pretreatment with peroxynitrite scavengers hesperetin or 5, 10, 15, 20-tetrakis-[4-sulfonatophenyl]-porphyrinato-iron [III]. Site-directed mutagenesis and electrospray ionization mass spectrometry analyses showed that Cys-298 of AR was readily oxidized to sulfenic acid by peroxynitrite. Treatment with bradykinin and insulin led to a phosphatidylinositol 3-kinase (PI3K)-dependent increase in the phosphorylation of endothelial NOS at Ser-1177 and, even in the absence of ischemia, was sufficient in activating AR. Activation of AR by bradykinin and insulin was reversed upon reduction with dithiothreitol or by inhibiting NOS or PI3K. Treatment with AR inhibitors sorbinil or tolrestat reduced post-ischemic recovery in the rat hearts subjected to global ischemia and increased the infarct size when given before ischemia or upon reperfusion. These results suggest that AR is a cardioprotective protein and that its activation in the ischemic heart is due to peroxynitrite-mediated oxidation of Cys-298 to sulfenic acid via the PI3K/Akt/endothelial NOS pathway.
authors.affiliation: Institute of Molecular Cardiology, University of Louisville, Louisville, KY 40202, USA.
authors.forename: Karin
authors.initials: K
authors.lastname: Kaiserova
authors.forename: Xian-Liang
authors.initials: XL
authors.lastname: Tang
authors.forename: Sanjay
authors.initials: S
authors.lastname: Srivastava
authors.forename: Aruni
authors.initials: A
authors.lastname: Bhatnagar
mesh_terms: D000449:Aldehyde Reductase / Q000037:antagonists & inhibitors / Q000378:metabolism*; D000818:Animals; D001920:Bradykinin / Q000494:pharmacology; D004229:Dithiothreitol / Q000494:pharmacology; D004789:Enzyme Activation / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005290:Ferric Compounds / Q000494:pharmacology; D005947:Glucose / Q000378:metabolism; D006569:Hesperidin / Q000494:pharmacology; D007004:Hypoglycemic Agents / Q000494:pharmacology; D048289:Imidazolidines / Q000494:pharmacology; D007328:Insulin / Q000494:pharmacology; D015227:Lipid Peroxidation / Q000187:drug effects; D008297:Male; D008665:Metalloporphyrins / Q000494:pharmacology; D015428:Myocardial Reperfusion Injury / Q000201:enzymology* / Q000473:pathology; D009206:Myocardium / Q000201:enzymology* / Q000473:pathology; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D009281:Naphthalenes / Q000494:pharmacology; D009569:Nitric Oxide / Q000378:metabolism*; D052248:Nitric Oxide Synthase Type I / Q000037:antagonists & inhibitors / Q000378:metabolism; D052247:Nitric Oxide Synthase Type II / Q000037:antagonists & inhibitors / Q000378:metabolism*; D030421:Peroxynitrous Acid / Q000378:metabolism; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D000081082:Phosphoinositide-3 Kinase Inhibitors; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D051381:Rats; D015398:Signal Transduction / Q000187:drug effects; D013012:Sorbitol / Q000494:pharmacology; D014665:Vasodilator Agents / Q000494:pharmacology
chemical_list: D000449:Aldehyde Reductase; D001920:Bradykinin; D004229:Dithiothreitol; D004791:Enzyme Inhibitors; D005290:Ferric Compounds; D005947:Glucose; D006569:Hesperidin; D007004:Hypoglycemic Agents; D048289:Imidazolidines; D007328:Insulin; D008665:Metalloporphyrins; D019331:NG-Nitroarginine Methyl Ester; D009281:Naphthalenes; D009569:Nitric Oxide; D052248:Nitric Oxide Synthase Type I; D052247:Nitric Oxide Synthase Type II; D030421:Peroxynitrous Acid; D019869:Phosphatidylinositol 3-Kinases; D000081082:Phosphoinositide-3 Kinase Inhibitors; D051057:Proto-Oncogene Proteins c-akt; D013012:Sorbitol; D014665:Vasodilator Agents; C112917:5,10,15,20-tetrakis(2,4,6-trimethyl-3,3-disulfonatophenyl)porphyrinato iron(III); C040550:tolrestat; C496318:Nos2 protein, rat; C026411:sorbinil; C013015:hesperetin