Myocardial Reprogramming by HMGN1 Underlies Heart Defects in Trisomy 21 [scRNA-seq]

Congenital heart defects (CHD) are the most common form of developmental abnormalities, occurring in ~1% of live births, and can arise due to altered dosage of genes essential for cardiogenesis. Aneuploidy accounts for nearly 15% of CHD and the most frequent form involves trisomy of chromosome 21 (Ch21), resulting in Down Syndrome (DS). Here we used single cell RNA-seq, CRISPR-activation with single cell RNA-seq, single cell ATAC-seq and Cut&Tag epigenomic profiling to define the molecular disruptions occuring with Trisomy 21 and upregulation of the Ch21 epigenetic factor HMGN1. These experiments were performed in human pluripotent stem cells (hiPSCs) or in directed differentiation to cardiomyocyte lineages at days 10 and 20. Overall design: We used human pluripotent stem cells (hIPSCs) from an individual who was mosaic for Down Syndrome. Thus we compare cells that are trisomic for Ch21 with cells that are isogenically similar and disomic for Ch21. As well, we generated a CRISPR-activation knock-in to disomic cells and used sgRNAs directed to chromosome 21 genes. Sample replicates are defined and all single cell samples were processed with 10X Genomics pipelines. Cut&Run samples were processed with Epicypher reagents. All samples were isolated with Accutase or Trypsin reagents.