title: Parstatin(1-26): the putative signal peptide of protease-activated receptor 1 confers potent protection from myocardial ischemia-reperfusion injury.
abstract: Parstatin, the N-terminal 41-amino-acid peptide cleaved by thrombin from the protease-activated receptor 1, protects against rat myocardial ischemia and reperfusion injury. In this study, we determined that the parstatin fragment 1-26, the putative signal peptide of protease-activated receptor 1, contains the functional domain of parstatin. We assessed a synthesized parstatin(1-26) peptide in an in vivo rat model of myocardial regional ischemia-reperfusion injury (n = 6/group). Infarct size in control rat hearts was 58 +/- 1% area at risk. Parstatin(1-26) was able to reduce infarct size to 13 +/- 1% (P < 0.001) and 22 +/- 1% area at risk (P < 0.01) when given before or after reperfusion. The infarct-sparing effects of parstatin(1-26) were abolished by inhibition of G(i) proteins (pertussis toxin), phosphoinositide 3-kinase/Akt (wortmannin), nitric-oxide synthase (NOS; N(G)-monomethyl-l-arginine), soluble guanylyl cyclase [1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ)], and sarcolemmal and mitochondrial K(ATP) channels [glibenclamide, 5-hydroxydecanoic acid, and sodium (5-(2-(5-chloro-2-methoxybenzamido)ethyl)-2-methoxyphenylsulfonyl) (methylcarbamothioyl)amide (HMR 1098)]. Parstatin(1-26) cardioprotection was also abolished by atractyloside, a mitochondrial permeability transition pore (mPTP) opener. The inhibitors and opener alone had no effect on infarct size. Furthermore, preischemic treatment with parstatin(1-26) increased Akt and endothelial NOS phosphorylation at the time of reperfusion. After a 120-min reperfusion, parstatin(1-26) increased nitric oxide levels (12 +/- 0.4 to 17 +/- 0.9 mmol/g tissue) and cyclic GMP levels (87 +/- 21 to 395 +/- 36 pmol/g tissue). Parstatin(1-26) treatment either before or after ischemia results in an extremely efficacious protection against ischemia-reperfusion injury that depends on a G(i) protein-mediated pathway involving mPTP, the end effector of the preconditioning pathway. This suggests that parstatin(1-26) has a potential therapeutic role in the treatment of ischemia and reperfusion injury.
authors.affiliation: Division of Cardiovascular Medicine, Medical College of Wisconsin, 8701 Watertown Plank Rd., Milwaukee, WI 53226, USA.
authors.forename: Kasi V
authors.initials: KV
authors.lastname: Routhu
authors.forename: Nikos E
authors.initials: NE
authors.lastname: Tsopanoglou
authors.forename: Jennifer L
authors.initials: JL
authors.lastname: Strande
mesh_terms: D000818:Animals; D019206:GTP-Binding Protein alpha Subunits, Gi-Go / Q000502:physiology; D008297:Male; D009203:Myocardial Infarction / Q000473:pathology / Q000517:prevention & control; D015428:Myocardial Reperfusion Injury / Q000473:pathology / Q000517:prevention & control*; D010446:Peptide Fragments / Q000494:pharmacology* / Q000627:therapeutic use; D021382:Protein Sorting Signals; D051381:Rats; D017207:Rats, Sprague-Dawley; D044463:Receptor, PAR-1 / Q000737:chemistry*; D015398:Signal Transduction
chemical_list: D010446:Peptide Fragments; D021382:Protein Sorting Signals; D044463:Receptor, PAR-1; D019206:GTP-Binding Protein alpha Subunits, Gi-Go