title: In vivo administration of calpeptin attenuates calpain activation and cardiomyocyte loss in pressure-overloaded feline myocardium.
abstract: Calpain activation is linked to the cleavage of several cytoskeletal proteins and could be an important contributor to the loss of cardiomyocytes and contractile dysfunction during cardiac pressure overload (PO). Using a feline right ventricular (RV) PO model, we analyzed calpain activation during the early compensatory period of cardiac hypertrophy. Calpain enrichment and its increased activity with a reduced calpastatin level were observed in 24- to 48-h-PO myocardium, and these changes returned to basal level by 1 wk of PO. Histochemical studies in 24-h-PO myocardium revealed the presence of TdT-mediated dUTP nick-end label (TUNEL)-positive cardiomyocytes, which exhibited enrichment of calpain and gelsolin. Biochemical studies showed an increase in histone H2B phosphorylation and cytoskeletal binding and cleavage of gelsolin, which indicate programmed cardiomyocyte cell death. To test whether calpain inhibition could prevent these changes, we administered calpeptin (0.6 mg/kg iv) by bolus injections twice, 15 min before and 6 h after induction of 24-h PO. Calpeptin blocked the following PO-induced changes: calpain enrichment and activation, decreased calpastatin level, caspase-3 activation, enrichment and cleavage of gelsolin, TUNEL staining, and histone H2B phosphorylation. Although similar administration of a caspase inhibitor, N-benzoylcarbonyl-Val-Ala-Asp-fluoromethylketone (Z-VD-fmk), blocked caspase-3 activation, it did not alleviate other aforementioned changes. These results indicate that biochemical markers of cardiomyocyte cell death, such as sarcomeric disarray, gelsolin cleavage, and TUNEL-positive nuclei, are mediated, at least in part, by calpain and that calpeptin may serve as a potential therapeutic agent to prevent cardiomyocyte loss and preserve myocardial structure and function during cardiac hypertrophy.
authors.affiliation: Gazes Cardiac Research Institute, Charleston, SC 29425-2221, USA.
authors.forename: Santhosh K
authors.initials: SK
authors.lastname: Mani
authors.forename: Hirokazu
authors.initials: H
authors.lastname: Shiraishi
authors.forename: Sundaravadivel
authors.initials: S
authors.lastname: Balasubramanian
authors.forename: Kentaro
authors.initials: K
authors.lastname: Yamane
authors.forename: Meenakshi
authors.initials: M
authors.lastname: Chellaiah
authors.forename: George
authors.initials: G
authors.lastname: Cooper
authors.forename: Naren
authors.initials: N
authors.lastname: Banik
authors.forename: Michael R
authors.initials: MR
authors.lastname: Zile
authors.forename: Dhandapani
authors.initials: D
authors.lastname: Kuppuswamy
mesh_terms: D000590:Amino Acid Chloromethyl Ketones / Q000494:pharmacology; D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D002154:Calpain / Q000037:antagonists & inhibitors* / Q000378:metabolism; D006332:Cardiomegaly / Q000150:complications / Q000188:drug therapy* / Q000201:enzymology / Q000473:pathology; D053148:Caspase 3 / Q000378:metabolism; D061945:Caspase Inhibitors; D002415:Cats; D015853:Cysteine Proteinase Inhibitors / Q000008:administration & dosage / Q000494:pharmacology*; D004151:Dipeptides / Q000008:administration & dosage / Q000494:pharmacology*; D004195:Disease Models, Animal; D004789:Enzyme Activation; D018260:Gelsolin / Q000378:metabolism; D006333:Heart Failure / Q000201:enzymology / Q000209:etiology / Q000473:pathology / Q000517:prevention & control*; D006657:Histones / Q000378:metabolism; D020287:In Situ Nick-End Labeling; D007275:Injections, Intravenous; D008026:Ligation; D008297:Male; D032383:Myocytes, Cardiac / Q000187:drug effects* / Q000201:enzymology / Q000473:pathology; D010766:Phosphorylation; D011651:Pulmonary Artery / Q000601:surgery; D013997:Time Factors
chemical_list: D000590:Amino Acid Chloromethyl Ketones; D061945:Caspase Inhibitors; D015853:Cysteine Proteinase Inhibitors; D004151:Dipeptides; D018260:Gelsolin; D006657:Histones; C484771:benzyloxycarbonyl-valyl-aspartic acid fluoromethyl ketone; C071482:calpeptin; D002154:Calpain; C505410:Casp3 protein, rat; D053148:Caspase 3