Conversion of human adipose-derived stem cells into functional and expandable endothelial-like cells for cell-based therapies

Background: Ischemic vascular diseases are the major cause of death worldwide. In recent years, endothelial cell (EC)-based approaches to vascular regeneration are increasingly viable strategies for treating ischemic diseases, but their applications are challenged by the difficulties in their efficient generation and stable maintenance. Here, we show an alternative protocol that facilitates the generation of functional and expandable ETS variant 2 (ETV2)-induced endothelial-like cells (EiECs) from human adipose-derived stem cells (hADSCs), providing a potential source of cells for autologous ECs to treat ischemic vascular diseases.

Methods: hADSCs were obtained from fresh human adipose tissue. Passage 3 hADSCs were transduced with doxycycline (DOX)-inducible ETV2 transcription factor; purified ETV2-hADSCs were induced into endothelial-like cells using a two-stage induction culture system composed of small molecule compounds and cell factors. EiECs were evaluated for their surface markers, proliferation, gene expression, secretory capacity, and effects on vascular regeneration in vivo.

Results: We found that short-term ETV2 expression combined with TGF-β inhibition is sufficient for the generation of kinase insert domain receptor (KDR)+ cells from hADSCs within 10 days. KDR+ cells showed immature endothelial characteristics, and they can gradually mature in a chemically defined induction medium at the second stage of induction. Futher studies showed that KDR+ cells deriving EC-like cells could stably self-renew and expand about 10⁶-fold in 1 month, and they exhibited expected genome-wide molecular features of mature ECs. Functionally, these EC-like cells significantly promoted revascularization in a hind limb ischemic model.

Conclusions: We isolated highly purified hADSCs and effectively converted them into functional and expandable endothelial-like cells. Thus, the study may provide an alternative strategy to obtain functional EC-like cells with potential for biomedical and pharmaceutical applications.