Missense Mutation in Human CHD4 Causes Ventricular Noncompaction by Repressing ADAMTS1

Background:Left ventricular noncompaction (LVNC) is a prevalent cardiomyopathy associated with excessive trabeculation and thin compact myocardium. Patients with LVNC are vulnerable to cardiac dysfunction and at high risk of sudden death. Although sporadic and inherited mutations in cardiac genes are implicated in LVNC, understanding of the mechanisms responsible for human LVNC is limited. Methods:We screened the complete exome sequence database of the Pediatrics Cardiac Genomics Consortium and identified a cohort with a de novo CHD4 (chromodomain helicase DNA-binding protein 4) proband, CHD4(M202I), with congenital heart defects. We engineered a humanized mouse model of CHD4(M202I) (mouse CHD4(M195I)). Histological analysis, immunohistochemistry, flow cytometry, transmission electron microscopy, and echocardiography were used to analyze cardiac anatomy and function. Ex vivo culture, immunopurification coupled with mass spectrometry, transcriptional profiling, and chromatin immunoprecipitation were performed to deduce the mechanism of CHD4(M195I)-mediated ventricular wall defects. Results:CHD4(M195I/M195I) mice developed biventricular hypertrabeculation and noncompaction and died at birth. Proliferation of cardiomyocytes was significantly increased in CHD4(M195I) hearts, and the excessive trabeculation was associated with accumulation of ECM (extracellular matrix) proteins and a reduction of ADAMTS1 (ADAM metallopeptidase with thrombospondin type 1 motif 1), an ECM protease. We rescued the hyperproliferation and hypertrabeculation defects in CHD4(M195I) hearts by administration of ADAMTS1. Mechanistically, the CHD4(M195I) protein showed augmented affinity to endocardial BRG1 (SWI/SNF-related, matrix-associated, actin-dependent regulator of chromatin, subfamily A, member 4). This enhanced affinity resulted in the failure of derepression of Adamts1 transcription such that ADAMTS1-mediated trabeculation termination was impaired. Conclusions:Our study reveals how a single mutation in the chromatin remodeler CHD4, in mice or humans, modulates ventricular chamber maturation and that cardiac defects associated with the missense mutation CHD4(M195I) can be attenuated by the administration of ADAMTS1.

Automated summary

This study reveals that the CHD4 mutation can cause ventricular wall defects, and that ADAMTS1 can improve this defect by regulating the function of CHD4. This research enhances our understanding of heart development and provides a new therapeutic strategy for treating heart diseases.