Transcriptome signatures of human induced pluripotent stem cell-derived cardiomyocytes classify cardiomyocyte subtype populations

We profiled the transcriptome of cardiomyocytes from hiPSCs throughout differentiation and at a single cell level to identify subpopulations. We further studied on the transcription factors NR2F2, TBX5, and HEY2 in these subpopulations. Overall design: Cardiomyocytes derived from human induced pluripotent stem cells (hiPSC-CMs) have become a powerful tool for human disease modeling and therapeutic testing. However, their use remains limited by their immaturity and heterogeneity. To characterize the source of this heterogeneity, we performed bulk RNA-seq on hiPSCs undergoing differentiation into cardiomyocytes over an extended time course followed by single-cell RNA-seq at a later time point (day 30). These analyses identified novel single-cell populations, characterized by the distinct or overlapping expression of TBX5, NR2F2, HEY2, ISL1, JARID2, and HOPX transcription factors. Analysis of RNA-seq data from hiPSC-CMs both during differentiation in vitro and from human heart tissues suggests these transcription factors underlie physiologically distinct lineages. Using CRISPR genome editing and ChIP-seq, in conjunction with patch clamp, calcium imaging, CYTOF, and single-cell Western analysis, we now demonstrate that these transcription factors play an essential role in specification of early atrial (NR2F2) and late ventricular (HEY2) cardiomyocytes. We RNA-sequenced NR2F2, TBX5, HEY2 gene edited lines as well as day 30 hiPSC-CMs overexpressing NR2F2, TBX5, and HEY2. These new targets, sequencing data, and methods provide a platform for improved investigation of in vitro cardiac heterogeneity.

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Churko JM, Garg P, Treutlein B, Venkatasubramanian M, Wu H, Lee J, Wessells QN, Chen SY, Chen WY, Chetal K, Mantalas G, Neff N, Jabart E, Sharma A, Nolan GP, Salomonis N, Wu JC