ABSTRACT: Isolation of specific cell types, including pluripotent stem cell (PSC)-derived populations, is frequently accomplished using cell surface antigens expressed by the cells of interest. However, specific antigens for many cell types have not been identified, making their isolation difficult. Here, we describe an efficient method for purifying cells based on endogenous miRNA activity. We designed synthetic mRNAs encoding a fluorescent protein tagged with sequences targeted by miRNAs expressed by the cells of interest. These miRNA switches control their own translation levels by sensing miRNA activities. Several miRNA switches (miR-1-, miR-208a-, and miR-499a-5p-switches) efficiently purified cardiomyocytes differentiated from human PSCs, and switches encoding the apoptosis inducer Bim enriched for cardiomyocytes without cell sorting. This approach is generally applicable, as miR-126-, miR-122-5p- and miR-375-switches purified endothelial cells, hepatocytes and INSULIN-producing cells differentiated from hPSCs, respectively. Thus, miRNA switches can purify cell populations for which other isolation strategies are unavailable. MYH6-EIP4 day8 differentiated cells (EGFP+) for miRNA, N=1 MYH6-EIP4 day8 differentiated cells (EGFP-) for miRNA, N=1 MYH6-EIP4 day20 differentiated cells (EGFP+) for miRNA, N=1 MYH6-EIP4 day20 differentiated cells (EGFP-) for miRNA, N=1 HUVEC for miRNA, N=2 AoSMC for miRNA, N=2 Hepatocytes for miRNA, N=2 NHDF for miRNA, N=2 MYH6-EIP4 iPSCs for mRNA, N=3 MYH6-EIP4 day18 cardiomyocytes (before transfection) for mRNA, N=3 MYH6-EIP4 day19 cardiomyocytes (miR-1-switch day1) for mRNA, N=3 MYH6-EIP4 day19 cardiomyocytes (without transfection) for mRNA, N=3 MYH6-EIP4 day25 cardiomyocytes (miR-1-switch day7) for mRNA, N=3 MYH6-EIP4 day25 cardiomyocytes (without transfection) for mRNA, N=3 201B7 d22 miR-208a-BFP sorted cells for mRNA, N=1 201B7 d22 miR-208a-BFP negative fraction sorted cells for mRNA, N=1 201B7 d22 SIRPA+LIN- sorted cells for mRNA, N=1 201B7 d22 SIRPA+LIN- negative fraction sorted cells for mRNA, N=1 201B7 d22 VCAM1+ sorted cells for mRNA, N=1 201B7 d22 VCAM1+negative fraction sorted cells for mRNA, N=1 MYH6-EIP4 day19 cardiomyocytes (miR-208a-Bim-switch day1) for mRNA, N=1 MYH6-EIP4 day19 cardiomyocytes (without transfection) for mRNA, N=1 MYH6-EIP4 day21 cardiomyocytes (miR-208a-Bim-switch day7) for mRNA, N=1 MYH6-EIP4 day21 cardiomyocytes (without transfection) for mRNA, N=1 MYH6-EIP4 day25 cardiomyocytes (miR-208a-Bim-switch day7) for mRNA, N=1 MYH6-EIP4 day25 cardiomyocytes (without transfection) for mRNA, N=1
