Hubrecht Institute, Royal Netherlands Academy of Arts and Sciences (KNAW) and University Medical Center Utrecht, Uppsalalaan 8, 3584 CT Utrecht, the Netherlands.
Department of Medical Physiology, University Medical Center Utrecht, Utrecht, the Netherlands.
Stem Cell Reports. 2023 Mar 14;18(3):749-764. doi: 10.1016/j.stemcr.2023.01.015. Epub 2023 Mar 2.
Arrhythmogenic cardiomyopathy (ACM) is an inherited progressive disease characterized by electrophysiological and structural remodeling of the ventricles. However, the disease-causing molecular pathways, as a consequence of desmosomal mutations, are poorly understood. Here, we identified a novel missense mutation within desmoplakin in a patient clinically diagnosed with ACM. Using CRISPR-Cas9, we corrected this mutation in patient-derived human induced pluripotent stem cells (hiPSCs) and generated an independent knockin hiPSC line carrying the same mutation. Mutant cardiomyocytes displayed a decline in connexin 43, NaV1.5, and desmosomal proteins, which was accompanied by a prolonged action potential duration. Interestingly, paired-like homeodomain 2 (PITX2), a transcription factor that acts a repressor of connexin 43, NaV1.5, and desmoplakin, was induced in mutant cardiomyocytes. We validated these results in control cardiomyocytes in which PITX2 was either depleted or overexpressed. Importantly, knockdown of PITX2 in patient-derived cardiomyocytes is sufficient to restore the levels of desmoplakin, connexin 43, and NaV1.5.
致心律失常性右室心肌病（ACM）是一种遗传性进行性疾病，其特征为心室的电生理和结构重构。然而，由于桥粒突变导致的致病分子途径仍知之甚少。在此，我们在一位临床诊断为 ACM 的患者中发现了桥粒斑蛋白内的一个新错义突变。我们使用 CRISPR-Cas9 在患者来源的人诱导多能干细胞（hiPSC）中纠正了该突变，并生成了携带相同突变的独立敲入 hiPSC 系。突变型心肌细胞显示连接蛋白 43、NaV1.5 和桥粒蛋白减少，这伴随着动作电位持续时间延长。有趣的是，配对样同源框 2（PITX2），一种作为连接蛋白 43、NaV1.5 和桥粒斑蛋白的转录因子的抑制剂，在突变型心肌细胞中被诱导。我们在对照心肌细胞中验证了这些结果，其中 PITX2 被耗尽或过表达。重要的是，在患者来源的心肌细胞中敲低 PITX2 足以恢复桥粒斑蛋白、连接蛋白 43 和 NaV1.5 的水平。
