EGFR inhibition led ROCK activation enhances desmosome assembly and cohesion in cardiomyocytes

Abstract

The epidermal growth factor receptor (EGFR) is a ubiquitously expressed receptor tyrosine kinase, which is dysregulated in several kinds of cancer and heart diseases. Arrhythmogenic cardiomyopathy (AC) is a familial heart disease in part caused by impaired desmosome turnover. Thus, stabilization of desmosome integrity, may provide potential new treatment options. Desmosomes, apart from cellular cohesion, provide the structural framework of a signaling hub. Here, we investigated the role of EGFR inhibition on cardiomyocyte cohesion under physiological and pathophysiological conditions using the murine plakoglobin knockout AC model, in which EGFR was upregulated. EGFR inhibition led to enhanced cardiomyocyte cohesion. Immunoprecipitation showed an interaction of EGFR and desmoglein 2 (DSG2). Immunostaining and AFM revealed enhanced DSG2 localization and binding at cell borders upon EGFR inhibition. Enhanced area composita length and desmosome assembly was observed upon EGFR inhibition, confirmed by enhanced DSG2 and desmoplakin (DP) recruitment to the cell borders. Thus, inhibiting EGFR, thereby stabilizing desmosome integrity, may provide new treatment options for AC.

Cardiomyocyte cohesion is increased after ADAM17 inhibition

“…Furthermore, increased levels of EGF, indicating an increased EGFR activity, also increased the protein levels of ADAM17 ( Santiago-Josefat et al, 2007 ). However, in our Jup −/− mice, which express low levels of DSG2 and high levels of EGFR ( Shoykhet et al, 2022 ), ADAM17 protein levels were not significantly increased. It has been suggested that the proteolytic activity of ADAM17 is not regulated by protein levels, but by posttranslational modifications ( Dusterhoft et al, 2019 ).…”

“…Upon knockdown of Adam17 using siRNA or application of the ADAM17 inhibitor for 24 h, we did not observe a change in cellular cohesion as compared to siNT (non-target) or vehicle treated HL-1 cardiomyocytes, respectively ( Figures 2B, C ). Since ADAM17 can transactivate the EGFR by EGF shedding, and EGFR inhibition can also lead to positive adhesiotropy ( Shoykhet et al, 2022 ), we assessed whether the TAPI-1-induced positive adhesiotropy requires EGFR. However, we did not observe changes in EGFR signaling ( Supplementary Figures 2C–F ).…”