Abstract

BackgroundLeft 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. MethodsWe screened the complete exome sequence database of the Pediatrics Cardiac Genomics Consortium and identified a cohort with a de novo chromodomain helicase DNA-binding protein 4 (CHD4) proband, CHD4M202I, with congenital heart defects. We engineered a patient-specific model of CHD4M202I (mouse CHD4M195I). 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 CHD4M195I-mediated ventricular wall defects. ResultsCHD4M195I/M195I mice developed biventricular hypertrabeculaion and noncompaction and died at birth. Proliferation of cardiomyocytes was significantly increased in CHD4M195I hearts, and the excessive trabeculation was associated with accumulation of extracellular matrix (ECM) proteins and a reduction of ADAMTS1, an ECM protease. We rescued the hyperproliferation and hypertrabeculation defects in CHD4M195I hearts by administration of ADAMTS1. Mechanistically, the CHD4M195I protein showed augmented affinity to endocardial BRG1. This enhanced affinity resulted in failure of derepression of Adamts1 transcription such that ADAMTS1-mediated trabeculation termination was impaired. ConclusionsOur 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 CHD4M195I can be attenuated by the administration of ADAMTS1. Clinical PerspectiveO_ST_ABSWhat Is New?C_ST_ABSO_LIA patient-specific mouse model of CHD4M202I develops ventricular hypertrabeculation and dies at birth. C_LIO_LIProliferation of cardiomyocytes is significantly enhanced in CHD4M195I mice. C_LIO_LIADAMTS1 is significantly downregulated in CHD4M195I mice. C_LIO_LIClose interaction between CHD4M195I and BRG1 robustly and continuously represses Adamts1 transcription, which impairs ADAMTS1-mediated termination of trabeculation in the developing mutant heart. C_LI What Are the Clinical Implications?O_LIThis study provides a unique mouse model of ventricular noncompaction cardiomyopathy that faithfully reflects human patients genetic condition without disturbing the target genes expression and localization. C_LIO_LITranscriptional repression of ECM protease ADAMTS1 by CHD4-BRG1 interaction is detrimental to ventricular wall maturation; maintaining appropriate ADAMTS1 levels in the heart could be a promising therapeutic approach for treating ventricular noncompaction cardiomyopathy. C_LI