Abstract P153: Role of Nonreceptor Tyrosine Kinases in Cardiac Fibrosis in a Mouse Model of Pressure Overload Hypertrophy

Abstract

During prolonged hypertrophic insult to the myocardium, while the function of cardiomyocytes needs to be protected, the hyperactivation of cardiac fibroblasts has to be curbed to prevent fibrosis. Previously, we showed that integrin-mediated non-receptor tyrosine kinase (NRTK) activation is required for normal functioning of both cardiac fibroblasts and cardiomyocytes. We hypothesized that inhibition of NRTKs in cardiac fibroblasts without affecting cardiomyocytes would be beneficial to the stressed myocardium. Our initial studies using kinase inactive forms of Src, Pyk2 and FAK expressed adenovirally in isolated primary cardiac fibroblasts showed that the pro-fibrotic signaling events as studied by fibronectin and collagen deposition are downregulated. Our in vivo studies in mouse transverse aortic constriction (TAC) model suggest that dasatinib, a multikinase NRTK inhibitor administration via a peritoneally implanted mini-osmotic pump is able to preserve ventricular geometry and function and reduce the accumulation of fibrotic extracellular matrix (ECM) proteins upon 4 wk pressure overload. Data obtained from cell culture experiments with kinase inactive NRTKs and dasatinib suggest that NRTK inhibition is able to reduce the proliferation, migration and mitogenic signaling in cardiac fibroblasts without affecting the cell survival pathways in cardiomyocytes. These data indicate that NRTKs play a significant pro-fibrotic role in cardiac fibroblasts and curbing the activity of NRTKs could be a potential therapeutic approach to treat fibrosis in hypertrophic heart diseases.