Temporal single-cell transcriptomic profiling of cardiac differentiation in human induced pluripotent stem cells with NOTCH1 mutations

Pathological variants in NOTCH1 have been implicated in multiple types of congenital heart defects including bicuspid aortic valve and hypoplastic left heart syndrome (HLHS). To probe how NOTCH1 deficiency affects cardiac development, we generated homozygous NOTCH1 knockout (N1KO) human induced pluripotent stem cells (iPSCs). We then ran single-cell RNA-seq to temporally profile transcriptomic changes during cardiac differentiation in wild type (WT) and N1KO iPSCs. We collected differentiating cells at multiple time points corresponding to different development stages, i.e., Day 0 (D0: pluripotent stem cell), D2 (mesoderm), D5 (cardiac mesoderm), D10 (cardiac progenitor), D14 (early cardiomyocyte), and D30 (fetal cardiomyocyte). Single-cell transcriptomics analysis reveals that NOTCH1 disruption impairs human ventricular cardiomyocyte differentiation and proliferation through balancing cell fate determination of cardiac mesoderm toward the first heart field, second heart field, and epicardial lineages. Overall design: Single-cell transcriptomic analysis of differentiating cells collected at different time points (D0, D2, D5, D10, D14 and D30) during cardiac differentiation of WT and N1KO human iPSCs.