Direct Reprogramming of Human Dermal Fibroblasts Into Endothelial Cells Using ER71/ETV2
Rationale: Direct conversion or reprogramming of human postnatal cells into endothelial cells (ECs), bypassing stem or progenitor cell status, is crucial for regenerative medicine, cell therapy, and pathophysiological investigation but has remained largely unexplored.
Objective: We sought to directly reprogram human postnatal dermal fibroblasts (HDFs) to ECs with vasculogenic and endothelial transcription factors (TFs) and determine their vascularizing and therapeutic potential.
Methods and Results: We utilized various combinations of seven EC TFs to transduce HDFs and found that ER71/ETV2 alone best induced endothelial features. KDR+ cells sorted at day 7 from ER71/ETV2-transduced HDFs showed less mature but enriched endothelial characteristics and thus were referred to as early reprogrammed ECs (rECs), and did not undergo maturation by further culture. After a period of several weeks' transgene-free culture followed by transient re-induction of ER71/ETV2, early rECs matured during three months of culture and showed reduced ETV2 expression, reaching a mature phenotype similar to postnatal human ECs. These were termed late rECs. While early rECs exhibited an immature phenotype, their implantation into ischemic hindlimbs induced enhanced recovery from ischemia. These two rECs showed clear capacity for contributing to new vessel formation through direct vascular incorporation in vivo. Paracrine or pro-angiogenic effects of implanted early rECs played a significant role in repairing hindlimb ischemia.
Conclusions: This study for the first time demonstrates that ER71/ETV2 alone can directly reprogram human postnatal cells to functional, mature ECs after an intervening transgene free period. These rECs could be valuable for cell therapy, personalized disease investigation, and exploration of the reprogramming process.
- Direct reprogramming
- Endothelial cells
- endothelial cell
- ets transcription factors
- Received August 25, 2016.
- Revision received December 15, 2016.
- Accepted December 21, 2016.