ERBB3 and NGFR mark distinct skeletal muscle progenitor cells in human development enabling enrichment and maturation of hPSC muscle

Abstract: Human pluripotent stem cells (hPSCs) can be directed to differentiate into skeletal muscle progenitor cells (SMPCs). However, the myogenic potential of hPSC-SMPCs compared to human fetal or adult satellite cells (Scs) remains unclear. This study demonstrates hPSC-SMPCs derived by commonly used protocols are functionally less mature than freshly-isolated human fetal or adult Scs. We utilized RNA-SEQ of human fetal Scs to identify differentially expressed genes including NGFR, ERBB3, which enriched for MYOD+ or PAX7+ cells. Furthermore, inhibition of TGFß (TGFßi) improved hPSC-muscle maturation in three independent lines as measured by TEM and expression of myosins. Engraftment of CRISPR/Cas9-corrected Duchenne Muscular Dystrophy (DMD) hiPSC-SMPC subpopulations treated with TGFßi in vivo, increased dystrophin-positive fibers to levels of engrafted cultured fetal Scs in mdx mouse models of DMD. This work provides the first characterization of the developmental status of hPSC-SMPCs and identifies candidates to enable robust myogenic activity in vitro and in vivo. Overall design: Profiled transcriptomes of uncultured fetal Scs, cultured fetal muscle cells, and differentiated fetal myotubes in comparison to day 50 NCAM+ hPSC-SMPCs and SMPC-derived myotubes by RNA-SEQ.