Different Differentiation Kinetics of Vascular Progenitor Cells in Primate and Mouse Embryonic Stem Cells

Abstract

Background— We demonstrated that vascular endothelial growth factor receptor 2 (VEGF-R2)-positive cells derived from mouse embryonic stem (ES) cells can differentiate into both endothelial cells and mural cells to suffice as vascular progenitor cells (VPCs). Here we examined whether VPCs occur in primate ES cells and investigated the differences in VPC differentiation kinetics between primate and mouse ES cells. Methods and Results— In contrast to mouse ES cells, undifferentiated monkey ES cells expressed VEGF-R2. By culturing these undifferentiated ES cells for 4 days on OP9 feeder layer, VEGF-R2 expression disappeared, and then reappeared after 8 days of differentiation. We then isolated these VEGF-R2–positive and vascular endothelial cadherin (VEcadherin)-negative cells by flow cytometry sorting. Additional 5-day reculture of these VEGF-R2 + VEcadherin − cells on OP9 feeder layer resulted in the appearance of platelet endothelial cell adhesion molecule-1 (PECAM1)-positive, VEcadherin-positive, endothelial nitric oxide synthase (eNOS)-positive endothelial cells. On a collagen IV-coated dish in the presence of serum, these cells differentiated into smooth muscle actin (SMA)-positive and calponin-positive mural cells (pericytes or vascular smooth muscle cells). Addition of 50ng/mL VEGF to the culture on a collagen IV-coated dish resulted in the appearance of PECAM1 + cells surrounded by SMA + cells. In addition, these differentiated VEGF-R2 + cells can form tube-like structures in a 3-dimensional culture. Conclusion— Our findings indicate that differentiation kinetics of VPCs derived from primate and mouse ES cells were different. Differentiated VEGF-R2 + VEcadherin − cells can act as VPCs in primates. To seek the clinical potential of VPCs for vascular regeneration, investigations of primate ES cells are indispensable.

Development of primitive and definitive hematopoiesis from nonhuman primate embryonic stem cells in vitro

“…In our study, the expression of FLK1 was upregulated on day 6, before hematopoietic development. This result is consistent with the recent report on vascular progenitor cell differentiation from cynomolgus monkey ES cells onto OP9 stromal cells (Sone et al, 2003). Furthermore, we observed that exogenous VEGF also enhances the development of vascular endothelial cadherin-positive endothelial colonies under the same culture conditions (K.U., T.H.…”

A Novel Role for Vascular Endothelial Growth Factor as an Autocrine Survival Factor for Embryonic Stem Cells during Hypoxia

“…Its expression was also documented in undifferentiated ES cells (63)(64)(65)(66). Our present findings indicate that VEGFR-2 is expressed in ES cells and that its expression is induced by hypoxia via a HIF-1␣-dependent pathway.…”

Potential use of endothelial progenitor cells for regeneration of the vasculature

“…Therefore, ES cells could be feasible as a novel cell source for therapeutic angiogenesis. Recently, we were able to clarify the differentiation process from human ES cells to mature vascular cells (Figure 1) [Sone et al 2007[Sone et al , 2003]. Unlike mouse ES cells, undifferentiated human ES cells already express VEGFR-2, but after differentiation, a VEGFR-2-positive but tumor rejection antigen 1-60 (TRA1-60; undifferentiated marker)-negative population emerged.…”