Supplementary Material for: Osteogenic Differentiation of Late-Outgrowth CD45-Negative Endothelial Progenitor Cells

Background/Aims: Late-outgrowth CD45-negative
endothelial colony-forming cells are implicated to be circulating
endothelial progenitor cells (EPCs), as they express endothelial cell
markers and can directly form blood vessels. As these cells share
characteristics of other progenitor cell phenotypes, late-outgrowth EPCs
were assayed for both multilineage differentiation capability and for
markers of pluripotency. Methods: Clonal single-colony
late-outgrowth EPCs were derived from human cord blood and assayed both
for multilineage differentiation capability in vitro and for markers of
pluripotency by qPCR. Results: Under osteogenic growth
conditions, these EPCs expressed the osteogenic markers RUNX2, COL1A1,
ALPL, and osteocalcin and demonstrated calcium deposition and bone
mineralization. Endothelial colony-forming cells expressed markers
associated with induced pluripotent stem cells, including SOX2, POU5F1,
c-MYC, and KLF4. Conclusions: Late-outgrowth EPCs express
markers associated with pluripotency and can directly express an
osteogenic phenotype under bone differentiation conditions in vitro.