Center for Genetic Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL (A.M.G., D.E.F., J.O., T.P., M.J.P., E.M.M.).
Department of Human Genetics, University of Chicago, IL (M.A.N.).
Circulation. 2021 Mar 30;143(13):1302-1316. doi: 10.1161/CIRCULATIONAHA.120.050432. Epub 2021 Jan 22.
Inherited cardiomyopathy associates with a range of phenotypes, mediated by genetic and nongenetic factors. Noninherited cardiomyopathy also displays varying progression and outcomes. Expression of cardiomyopathy genes is under the regulatory control of promoters and enhancers, and human genetic variation in promoters and enhancers may contribute to this variability.
We superimposed epigenomic profiling from hearts and cardiomyocytes, including promoter-capture chromatin conformation information, to identify enhancers for 2 cardiomyopathy genes, and . Enhancer function was validated in human cardiomyocytes derived from induced pluripotent stem cells. We also conducted a genome-wide search to ascertain genomic variation in enhancers positioned to alter cardiac expression and correlated one of these variants to cardiomyopathy progression using biobank data.
Multiple enhancers were identified and validated for and , including a key enhancer that regulates the switch from expression to expression. Deletion of this enhancer resulted in a dose-dependent increase in and faster contractile rate in engineered heart tissues. We searched for genomic variation in enhancer sequences across the genome, with a focus on nucleotide changes that create or interrupt transcription factor binding sites. The sequence variant, rs875908, disrupts a T-Box Transcription Factor 5 binding motif and maps to an enhancer region 2 kilobases from the transcriptional start site of Gene editing to remove the enhancer that harbors this variant markedly reduced expression in human cardiomyocytes. Using biobank-derived data, rs875908 associated with longitudinal echocardiographic features of cardiomyopathy.
Enhancers regulate cardiomyopathy gene expression, and genomic variation within these enhancer regions associates with cardiomyopathic progression over time. This integrated approach identified noncoding modifiers of cardiomyopathy and is applicable to other cardiac genes.
遗传性心肌病与一系列表型相关，由遗传和非遗传因素介导。非遗传性心肌病也表现出不同的进展和结局。心肌病基因的表达受启动子和增强子的调控，启动子和增强子中的人类遗传变异可能导致这种变异性。
我们将心脏和心肌细胞的表观基因组图谱（包括启动子捕获染色质构象信息）叠加起来，以鉴定 2 个心肌病基因和 的增强子。在诱导多能干细胞衍生的人心肌细胞中验证增强子的功能。我们还进行了全基因组搜索，以确定改变心脏表达的增强子中的基因组变异，并使用生物库数据将其中一个变体与心肌病进展相关联。
鉴定并验证了 和 的多个增强子，包括一个关键的增强子，该增强子调节从 表达到 表达的转换。该增强子的缺失导致工程化心脏组织中 表达的剂量依赖性增加和更快的收缩率。我们在整个基因组中搜索增强子序列中的基因组变异，重点关注创建或中断转录因子结合位点的核苷酸变化。序列变体 rs875908 破坏了 T 框转录因子 5 结合基序，并映射到 基因转录起始位点 2 千碱基对的增强子区域。基因编辑去除含有该变体的增强子，显著降低了人心肌细胞中 的表达。使用生物库衍生的数据，rs875908 与心肌病的纵向超声心动图特征相关。
增强子调节心肌病基因表达，这些增强子区域内的基因组变异与随着时间的推移心肌病的进展相关。这种综合方法鉴定了心肌病的非编码修饰因子，并可应用于其他心脏基因。
