EGFR Inhibition in Cardiomyocytes Stabilizes Cardiomyocyte Cohesion in a Murine Model for Arrhythmogenic Cardiomyopathy

Abstract

The epidermal growth factor receptor (EGFR) is a receptor tyrosine kinase ubiquitously expressed in different tissues, including the heart. EGFR is dysregulated in several kinds of cancer, as well as in heart diseases. Arrhythmogenic cardiomyopathy (ACM) is a familial heart disease and one of the underlying mechanisms is impaired desmosome turnover. The intercalated disc (ICD) not only provides cellular cohesion but can also provide the structural framework of a signaling hub. Thus, stabilizing desmosome integrity, thereby enhancing cardiomyocyte stability, may provide potential new treatment options. In this study, we investigated the role of EGFR inhibition on cardiomyocyte cohesion under physiological as well as under pathophysiological conditions using the cardiomyocyte‐specific plakoglobin knockout (Jup‐/‐) ACM model in which EGFR was upregulated. Dissociation assays in HL‐1 cells and murine cardiac slice cultures showed that EGFR inhibition by erlotinib similar to SRC inhibition enhanced cardiomyocyte cohesion. Immunoprecipitation showed an interaction of EGFR, desmoglein 2 (DSG2) and desmoplakin (DP), indicating that altered EGFR signaling might affect desmosomes. Immunostainings and atomic force microscopy (AFM) revealed enhanced DSG2 localization and binding at the cell borders upon EGFR inhibition. In addition, during desmosome assembly induced by a Ca2+‐switch, DSG2 and DP were augmented at the cell borders after EGFR or SRC inhibition. Our study shows that EGFR inhibition by erlotinib leads to increased DSG2 binding and desmosome assembly, which stabilizes cardiomyocyte cohesion in the ACM mouse model. Because EGFR inhibition by erlotinib is already used in cancer patients, these data reveal a potential new therapeutic strategy in ACM.