Human fibroblasts can be differentiated into endothelial progenitor cells by direct reprogramming via ETV-2 transfection. Previously, we have shown that the efficacy of direct reprogramming can be enhanced by hypoxia treatment. In this study, we aim to investigate whether the efficacy of direct reprogramming of fibroblasts into EPCs via Ets variant gene 2 (ETV2) transfection can be increased with hepatocyte growth factor (HGF) treatment. Foreskin-derived fibroblasts were cultured in standard medium (DMEM/F12 supplemented with fetal bovine serum). They were then transduced with a viral vector expressing ETV2 in culture medium supplemented with HGF. The transduced fibroblasts were cultured in endothelial cell medium supplemented with HGF for 28 days. The efficacy of direct reprogramming was evaluated based on expression of CD31 and VEGFR2 markers by transduced cells. Phenotypic and functional characterization of induced EPCs were also confirmed by expression of particular genes and in vitro angiogenesis assays. Our results showed that HGF significantly increased the efficacy of direct reprogramming of fibroblasts towards EPCs via ETV2 transcription factors; efficiency increased from 5.41±1.51% for ETV2 transduction alone to 12.31±2.15% for ETV2 transduction combined with HGF treatment. These findings suggest the rationale for combined use of ETV2 and HGF in direct in vitro reprogramming of fibroblasts into EPCs.
ETV2, direct reprogramming, hepatocyte growth factor, endothelial progenitor cell, fibroblasts, pluripotent stem cells