ADAP1 limits neonatal cardiomyocyte hypertrophy by reducing integrin cell surface expression

Hugo Giguère,Vanessa Oliveira,Gino Laberge,Mannix Auger-Messier,Jonathan Berthiaume,Audrey-Ann Dumont

doi:10.1038/s41598-018-31784-w

Hugo Giguère, Vanessa Oliveira + Show 4 more

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https://doi.org/10.1038/s41598-018-31784-w

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Journal: Scientific Reports	Publication Date: Sep 11, 2018
Citations: 11	License type: open-access

Affiliation: Université de Sherbrooke

Abstract

The ArfGAP with dual PH domains 1 (ADAP1) regulates the activation of the hypertrophic mitogen-activated protein kinase ERK1/2 pathway in non-cardiomyocytes. However, its role in cardiomyocytes is unknown. Our aim was to characterize the role of ADAP1 in the hypertrophic process of cardiomyocytes. We assessed the expression of ADAP1 in the hearts of adult and neonatal rats by RT-qPCR and Western blotting and showed that it is preferentially expressed in cardiomyocytes. Adenoviral-mediated ADAP1 overexpression in cultured rat neonatal ventricular cardiomyocytes limited their serum-induced hypertrophic response as measured by immunofluorescence microscopy. Furthermore, ADAP1 overexpression completely blocked phenylephrine- and Mek1 constitutively active (Mek1ca) mutant-induced hypertrophy in these cells. The anti-hypertrophic effect of ADAP1 was not caused by a reduction in protein synthesis, interference with the Erk1/2 pathway, or disruption of the fetal gene program activation, as assessed by nascent protein labeling, Western blotting, and RT-qPCR, respectively. An analysis of cultured cardiomyocytes by confocal microscopy revealed that ADAP1 partially re-organizes α-actinin into dense puncta, a phenomenon that is synergized by Mek1ca overexpression. Biotin labeling of cell surface proteins from cardiomyocytes overexpressing ADAP1 revealed that it reduces the surface expression of β1-integrin, an effect that is strongly potentiated by Mek1ca overexpression. Our findings provide insights into the anti-hypertrophic function of ADAP1 in cardiomyocytes.

Highlights

ArfGAP with dual PH domains 1 (ADAP1), known as centaurin-α1, is a GTPase-activating protein (GAP) that regulates the activity of small GTPases from the ADP-ribosylation factor (ARF) family[1]
We show for the first time that ADAP1 can block cardiomyocyte hypertrophy in vitro by reducing the expression of β1-integrin at the cell surface
The overexpression of ADAP1 completely blocked the phenylephrine-induced hypertrophy of rat neonatal ventricular cardiomyocytes (RNVC) (Fig. 3A). Since both serum- and phenylephrine-dependent responses in cardiomyocytes commonly converge toward the hypertrophic MEK1-ERK1/2 signaling pathway[10], we investigated how ADAP1 would impact the effect on RNVC cell size of overexpressing a Mek[1] constitutively active mutant (Mek1ca)

Summary

Introduction

ArfGAP with dual PH domains 1 (ADAP1), known as centaurin-α1, is a GTPase-activating protein (GAP) that regulates the activity of small GTPases from the ADP-ribosylation factor (ARF) family[1]. ADAP1 interacts with nucleolin, Kif13b, and protein kinase C3–5, and is functionally linked with the activation of the mitogen-activated protein kinases (MAPKs) ERK1/26,7, which is of particular interest in a cardiac context, especially since the MEK1-ERK1/2 pathway supports and potentiates cardiac hypertrophy[8,9,10]. This signaling pathway is activated in response to several stresses in the heart, including hypertrophic agonist stimulation and mechanical stretching via integrins[11,12]. Β1-integrin overexpression in cultured cardiomyocytes promotes cell hypertrophy[24], while down-regulation of β1-integrin at the surface of cardiomyocytes impedes such hypertrophy[25]

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