[Calpains and cardiac diseases].
Calpains are a large family of cytosolic cysteine proteases composed of at least fourteen distinct isoforms. The family can be divided into two groups on the basis of distribution: ubiquitous and tissue-specific. Our current knowledge about calpains properties apply mainly to the ubiquitous isozymes, micro- and milli-calpain (classic calpains). These forms are activated after autolysis. Translocation and subsequent interactions with phospholipids of these enzymes increase their activity. Calpains are able to cleave a subset of substrates, as enzymes, structural and signalling proteins. Cardiac pathologies, such as heart failure, atrial fibrillation or clinical states particularly ischemia reperfusion, are associated with an increase of cytosolic calcium and in this regards, calpain activation has been evoked as one of the mediators leading to myocardial damage. Calpain activities have been shown to be increased in hearts experimentally subjected to ischemia reperfusion or during hypertrophy, but also in atrial tissue harvested from patients suffering from atrial fibrillations. These activities have been related to an increase of the proteolysis of different myocardial components, particularly, troponins, which are major regulators of the contraction of cardiomyocytes. Moreover, recent works have demonstrated that calpains are involved in the development of myocardial cell death by necrosis or apoptosis.
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Laboratoire de physiopathologie et pharmacologie cardiovasculaires expérimentales (LPPCE), IFR N 100, Faculté de médecine, 7, boulevard Jeanne-d'Arc, BP 87900, 21079 Dijon, France. caroline.perrin@u-bourgogne.fr
Vergely
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Rochette
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D000818:Animals; D002154:Calpain / Q000502:physiology*; D006331:Heart Diseases / Q000209:etiology*; D006801:Humans
D002154:Calpain