Precise genomic editing of a pathogenic RBM20 mutation rescues dilated cardiomyopathy. Precise genomic editing of a pathogenic RBM20 mutation rescues dilated cardiomyopathy

Mutations in RNA binding motif protein 20 (RBM20) are a common cause of dilated cardiomyopathy (DCM). Many RBM20 mutations cluster within an arginine/serine rich (RS-rich) domain, resulting in mis-localization of RBM20 to ribonucleoprotein granules within the cytoplasm, abnormal splicing of cardiac genes, and cardiomyocyte dysfunction. We used adenine base editing (ABE) and prime editing to correct pathogenic p.R634Q and p.R636S mutations in the RS-rich domain in human isogenic induced pluripotent stem cell-derived cardiomyocytes. We also created humanized Rbm20R636Q mutant mice, which succumbed to severe cardiac dysfunction, heart failure and premature death. Systemic delivery of ABE components by adeno-associated virus in these mice restored cardiac function and extended life span. These findings demonstrate the potential of precise correction of genetic mutations as a promising therapeutic approach for DCM. Overall design: We analyzed the transcriptome of single cardiac nulcei from the 6-month old heart of the following genotypes: WT, RBM20 homozygous mutation, RBM20 heterzygous mutation, and RBM20 homozygous mutation with gene editing correction.

RNA结合基序蛋白20（RNA binding motif protein 20, RBM20）的突变是扩张型心肌病（dilated cardiomyopathy, DCM）的常见致病原因。多数RBM20突变聚集于精氨酸/丝氨酸富集（arginine/serine rich, RS-rich）结构域内，可导致RBM20错误定位至细胞质内的核糖核蛋白颗粒，引发心脏基因剪接异常与心肌细胞功能障碍。本研究采用腺嘌呤碱基编辑（adenine base editing, ABE）与先导编辑（prime editing）技术，对人类同基因诱导多能干细胞衍生心肌细胞中RS富集结构域内的致病性p.R634Q及p.R636S突变进行校正。同时构建了人源化Rbm20^R636Q突变小鼠模型，该模型小鼠会出现严重心脏功能障碍、心力衰竭并发生过早死亡。通过腺相关病毒（adeno-associated virus, AAV）系统性递送ABE组分至该小鼠体内后，可恢复其心脏功能并延长生存期。上述研究结果证实，精准校正致病基因突变有望成为扩张型心肌病的潜在治疗策略。整体实验设计：本研究对以下基因型的6月龄小鼠心脏单个心肌细胞核转录组进行了分析：野生型（WT）、RBM20纯合突变型、RBM20杂合突变型，以及经基因编辑校正后的RBM20纯合突变型。