Human Hematopoietic Stem Cells Enhance Maturational Differentiation of hiPSC-Derived Cardiomyocytes on Xeno-Free MatriClone-Plastic via EGFR/MAPK/ERK Signaling Pathway

Background/Objectives: Only substantial quantities of xeno-free human induced pluripotent stem cell (hiPSC)-derived cardiomyocytes (CMs) (hiPSC-CMs) with stable quality and structural and functional maturity can meet the demand for cardiac cell therapy. The use of xeno-free microcarriers can significantly increase cell yield. Co-culturing with hematopoietic stem cells (HSCs) simulates the environment in vivo and has a necessary impact on the development of CMs. However, no microcarrier-based protocol for xeno-free hiPSC-CM culture has yet been established, and the effects of HSCs on CM development and their underlying mechanisms remain unclear. Therefore, this study aims to investigate these issues. Methods: We used a xeno-free microcarrier (plastic) culture system coated by a defined xeno-free matrix (MatriClone) to expand hiPSCs and hiPSC-CMs with human hematopoietic stem cells (hHSCs). Using RNA sequencing (RNA-seq), cytokine assay, and various cellular molecular techniques, we investigated the role of hHSCs in cardiac differentiation and maturation, and underlying mechanisms. Results: hiPSCs were evenly distributed on the surface of plastic coated with 1 μg/cm2 MatriClone (MatriClone-Plastic), increasing and sustaining pluripotency marker levels. Directed differentiation of hiPSCs on 1 μg/cm2 MatriClone-Plastic induced a larger number of CMs, and the level of cardiac differentiation was also significantly improved. When hHSCs were co-cultured with cells at the cardiac progenitor cell stage, results from electron microscopy, electrophysiology, and qPCR showed that hiPSC-CMs significantly promoted cardiac structural and functional maturation. The co-cultured hHSCs released multiple cytokines that were changed dynamically at different time points, and that were highly likely to activate the epidermal growth factor receptor (EGFR)/mitogen-activated protein kinase (MAPK)/extracellular signal-regulated kinase (ERK) signaling pathway to promote cardiac development and maturation. Conclusions: hHSCs can efficiently promote differentiation and maturation of xeno-free hiPSC-CMs on MatriClone-Plastic via the EGFR/MAPK/ERK signaling pathway.