Abstract 15113: A Novel Purification Method for Cardiomyocytes and Endothelial Cells Derived From Human Pluripotent Stem Cells Using Microrna-responsive Messenger Rna

Abstract

MicroRNAs (miRNAs) are small non-coding RNA that controls gene expression through translational regulation or mRNA cleavage. Recent progress in synthetic biology demonstrated that synthetic “RNA switches” enable to regulate gene expression depending on the intracellular environment. Here we show that synthetic mRNA technologies that modulate reporter protein expression by sensing miRNA activities enable purification of target cells in a safe and effective manner. To select cardiac-specific miRNA candidates, we performed miRNA microarray analyses using human induced pluripotent stem cell (hiPSC) line integrated MYH6 promoter driven EGFP cassette. We found 14 candidates, and synthesized individually these 14 miRNA-responsive OFF switch mRNAs (miR-switches) containing the sequence of blue fluorescent protein (TagBFP). We individually transfected them with EGFP mRNA into differentiated cells including cardiomyocytes derived from human pluripotent stem cell (hPSCs). We found that several cells transfected with miR-1- or miR-208-switches diminished TagBFP intensity, and sorting of these cells yielded high populations of troponin T-positive cardiomyocytes reproducibly and significantly (e.g., up to >98% in five hPSC lines). In addition, we developed a non-sorting system for purification of cardiomyocytes using miR-switch that code apoptosis-inducible protein (up to >97%). These cardiomyocytes purified by miR-switches were successfully engrafted in mouse heart and did not form tumor even when injected into testes of SCID mice. We next examined whether the system can be applied to purify endothelial cells, and confirmed that several miR-switches enabled high purification of CD31+ cells from differentiated derivatives of hPSCs (up to >98%), which have the function of tube formation like HUVEC. Moreover, the use of multiple miRNA-responsive mRNAs enabled simultaneous and high purification of cardiomyocytes and endothelial cells from heterogeneous population derived from hPSCs induced by single differentiation method (up to >98%). Our results suggest that miR-switch technology can be used for a variety of purposes including purification in any type of cells.