Heart failure encompasses a heterogeneous set of clinical features that converge on impaired cardiac contractile function^1,2 and presents a growing public health concern. Previous work has highlighted changes in both transcription and protein expression in failing hearts^3,4, but may overlook molecular changes in less prevalent cell types. Here we identify extensive molecular alterations in failing hearts at single-cell resolution by performing single-nucleus RNA sequencing of nearly 600,000 nuclei in left ventricle samples from 11 hearts with dilated cardiomyopathy and 15 hearts with hypertrophic cardiomyopathy as well as 16 non-failing hearts. The transcriptional profiles of dilated or hypertrophic cardiomyopathy hearts broadly converged at the tissue and cell-type level. Further, a subset of hearts from patients with cardiomyopathy harbour a unique population of activated fibroblasts that is almost entirely absent from non-failing samples. We performed a CRISPR-knockout screen in primary human cardiac fibroblasts to evaluate this fibrotic cell state transition; knockout of genes associated with fibroblast transition resulted in a reduction of myofibroblast cell-state transition upon TGFβ1 stimulation for a subset of genes. Our results provide insights into the transcriptional diversity of the human heart in health and disease as well as new potential therapeutic targets and biomarkers for heart failure.

心力衰竭包含一系列异质的临床特征，这些特征集中在心脏收缩功能受损^1,2上，并引起了日益严重的公共卫生问题。先前的工作强调了衰竭心脏中转录和蛋白质表达的变化^3,4，但可能忽略了不太常见的细胞类型中的分子变化。在这里，我们通过对来自 11 颗扩张型心肌病心脏、15 颗肥厚型心肌病心脏以及 16 颗非衰竭心脏的左心室样本中近 600,000 个细胞核进行单核 RNA 测序，以单细胞分辨率识别衰竭心脏中广泛的分子改变。扩张型或肥厚型心肌病心脏的转录谱在组织和细胞类型水平上广泛趋同。此外，心肌病患者的心脏子集含有独特的活化成纤维细胞群，而在非失败样本中几乎完全不存在这种细胞群。我们在原代人心脏成纤维细胞中进行了 CRISPR 敲除筛选，以评估这种纤维化细胞状态转变；敲除与成纤维细胞转变相关的基因会导致部分基因在 TGFβ1 刺激后肌成纤维细胞状态转变减少。我们的研究结果提供了对人类心脏在健康和疾病中的转录多样性的见解，以及心力衰竭的新的潜在治疗靶点和生物标志物。