RAD-Deficient Human Cardiomyocytes Develop Hypertrophic Cardiomyopathy Phenotypes Due to Calcium Dysregulation.

Ya’Nan Li,Yafei Zhou,Xiaolei Li,Wen-Jing Lu,Jian Gao,Fujian Wu,Tao Dong,Xiaowei Li,Shuhong Ma,Feng Lan,Yongming Wang,Yun Chang,Xiaoqiu Tan,Siyao Zhang,Rui Bai

doi:10.3389/fcell.2020.585879

Abstract

Ras associated with diabetes (RAD) is a membrane protein that acts as a calcium channel regulator by interacting with cardiac L-type Ca2 + channels (LTCC). RAD defects can disrupt intracellular calcium dynamics and lead to cardiac hypertrophy. However, due to the lack of reliable human disease models, the pathological mechanism of RAD deficiency leading to cardiac hypertrophy is not well understood. In this study, we created a RRAD–/– H9 cell line using CRISPR/Cas9 technology. RAD disruption did not affect the ability and efficiency of cardiomyocytes differentiation. However, RAD deficient hESC-CMs recapitulate hypertrophic phenotype in vitro. Further studies have shown that elevated intracellular calcium level and abnormal calcium regulation are the core mechanisms by which RAD deficiency leads to cardiac hypertrophy. More importantly, management of calcium dysregulation has been found to be an effective way to prevent the development of cardiac hypertrophy in vitro.

Highlights

Cardiac hypertrophy is a significant adaptive change in response to various stimuli from inside and outside the body
Studies on mice indicated that deficiency of Ras associated with diabetes (RAD) function in cardiomyocytes, which can lead to an increased L-type Ca2+ current (ICa−L) via upregulation of L-type Ca2+ channels (LTCC) expression in the plasma membrane (Yada et al, 2007), significantly increased stress-induced cardiac hypertrophy and remodeling in vitro (Chang et al, 2007) and cardiac fibrosis in vivo (Zhang et al, 2011)
We reported an in vitro RAD deficient cardiomyocyte model derived from RRAD−/− hESCs using CRISPR/Cas9 for the first time

Summary

Introduction

Cardiac hypertrophy is a significant adaptive change in response to various stimuli from inside and outside the body. Ras associated with diabetes (RAD), a membrane protein consists of 308 amino acids, is encoded by human RRAD gene and is highly expressed in cardiomyocytes (Reynet and Kahn, 1993; Maguire et al, 1994). It acts as a calcium channel regulator by interacting with cardiac L-type Ca2+ channels (LTCC), which play a fundamental role in normal heart (Finlin et al, 2003). Due to the lack of a human heart disease model, the role of RAD functional defects in the human heart is unclear

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Results

Conclusion