Cardiac-Specific Overexpression of Caveolin-1 in Rats With Ischemic Cardiomyopathy Improves Arrhythmogenicity and Cardiac Remodelling.

Abstract

Ischemic cardiomyopathy (ICM) is associated with electrical and structural remodelling, leading to arrhythmias. Caveolin-1 (Cav1) is a membrane protein involved in the pathogenesis of ischemic injury. Cav1 deficiency has been associated with arrhythmogenicity. The current study aimed to determine how Cav1 overexpression inhibits arrhythmias and cardiac remodelling in ICM. ICM was modelled using left anterior descending (LAD) artery ligation for 4 weeks. Cardiac-specific Cav1 overexpression in ICM on arrhythmias, excitation-contraction coupling, and cardiac remodelling were investigated using the intramyocardial injection of an adeno-associated virus serotype 9 (AAV-9) system, carrying a specific sequence expressing Cav1 (AAVCav1) under the cardiac troponin T (cTnT) promoter. Cav1 overexpression decreased susceptibility to arrhythmias by upregulating gap junction connexin 43 (CX43) and reducing spontaneous irregular proarrhythmogenic Ca2+ waves in ventricular cardiomyocytes. It also alleviated ischemic injury-induced contractility weakness by improving Ca2+ cycling through normalizing Ca2+-handling protein levels and improving Ca2+ homeostasis. Masson stain and immunoblotting revealed that the deposition of excessive fibrosis was attenuated by Cav1 overexpression, inhibiting the transforming growth factor-β (TGF-β)/Smad2 signalling pathway. Coimmunoprecipitation assays demonstrated that the interaction between Cav1 and cSrc modulated CX43 expression and Ca2+-handling protein levels. Cardiac-specific overexpression of Cav1 attenuated ventricular arrhythmia, improved Ca2+ cycling, and attenuated cardiac remodelling. These effects were attributed to modulation of CX43, normalized Ca2+-handling protein levels, improved Ca2+ homeostasis, and attenuated cardiac fibrosis.