Specific induction of right ventricular-like cardiomyocytes from human pluripotent stem cells.

BACKGROUND: Applications employing human pluripotent stem cell-derived cardiomyocytes (hPSC-CMs) require well-characterized, chamber-specific hPSC-CMs. Distinct first heart field (FHF) and second heart field (SHF) cardiac progenitor populations give rise to the left ventricular (LV) and right ventricular (RV) cardiomyocytes, respectively. This developmental difference in cardiomyocyte origin suggests that chamber-specific cardiomyocytes have unique characteristics. Therefore, efficient strategies to differentiate human pluripotent stem cells (hPSCs) specifically to LV-like or RV-like cardiomyocytes are needed and it is still unknown whether there is a phenotypic difference between LV-like cardiomyocytes and RV-like cardiomyocytes derived from hPSCs. METHODS: An established hPSC cardiac differentiation protocol employing sequential GSK3β inhibition followed by Wnt inhibition (GiWi) was modified by addition of insulin or BMP antagonists during mesoderm formation. Cardiac progenitor populations were evaluated for FHF and SHF markers, and differentiated hPSC-CMs were characterized for chamber-specific markers. RESULTS: The GiWi protocol produced mainly FHF-like progenitor cells that gave rise to LV-like cardiomyocytes. Inhibition of endogenous BMP signaling during mesoderm induction using insulin or BMP antagonists reduced expression of FHF markers and increased expression of SHF markers in cardiac progenitor cells. hPSC-CMs arising from the SHF-like progenitor cells showed an RV-like gene expression pattern and exhibited phenotypic differences in spontaneous contraction rate, Ca(2+) transients, and cell size compared to control LV-like cardiomyocytes. CONCLUSION: This study establishes methodology to generate RV-like hPSC-CMs to support the development of disease modeling research using chamber-specific hPSC-CMs.