Up-regulation of JAK-STAT pathway promotes maturation of human stem cell-derived cardiomyocytes

hPSC-CM has been used to model cardiac-related disease phenotypes. However, the immaturity of hPSC-CM constrains their potential in cell-based therapy, disease modeling and drug discovery. To understand the molecular mechanism driving human PSC-CM maturation, we utilized a metabolic reporter cell line that allows for the purification of CM that reflects different physiological status (fetal-like or matured). To identify transcription factors and pathways that enhances CM maturation, bulk RNA sequencing was performed on low-GFP expressing matured CM and high-GFP expressing fetal-like CM. The results revealed up-regulated expression of pathways involved in interferon signaling and down-regulation of pathways related to cell cycle checkpoints. Utilising CRISPR-Cas9 technology, we generated a HK-1-GFP knock-in reporter cell line in H7 embryonic stem cells. Flow cytometry verified that ES-derived cardiomyocytes generated reflects the metabolic shift of cardiomyocytes as they mature. Quantitative polymerase chain reaction (qPCR) and western blot was performed to further confirm the aforementioned findings. In addition, we also performed functional assays, such as glycolytic stress test on low/high GFP expressing fetal-like or matured CM. Subsequently, bulk RNA sequencing was performed to identify the molecular pathways and transcription factors that enhances maturation in hES-CM.