Figure 5.

CD87⁺ progenitors (representing group no. 3) exhibit characteristics of endothelial microvasculature. (a) Gates for sorting CD87⁺ and CD87⁻ cells from 5-day BMP4-treated cultures (isotype control shown as gray dotted line). (b) Gene ontology analysis indicating enrichment of gene categories in CD87⁺ relative to CD87⁻ populations, based on 726 genes that were differentially expressed over threefold in CD87⁺ cells. (c) Partial list of vascular- and angiogenesis-related genes expressed at higher levels in CD87⁺ versus CD87⁻ populations (top). Red asterisks denote genes that are also expressed at higher levels in the microvascular dermal endothelial cell line HMEK-1, compared with the tubular epithelial cell line HK-2 (ref. 33). Partial list of vasculogenesis-related genes that are expressed at medium to high levels in both CD87⁺ and CD87⁻ populations is shown at the bottom. Analyses in (b,c) are based on an average of two genome-wide profiling experiments with cultures at different passages. (d–g) Developmental potential of sorted, GFP-tagged CD87⁺ and CD87⁻ populations, analyzed following additional culturing period of 7 d in FBS containing media. (d) Representative phase-contrast photomicrographs show development of microvascular networks in the CD87⁺ but not in CD87⁻ cultures. (e,f) Immunohistochemistry with von Willebrand factor and CD31 antibodies revealed specific staining (red) only in vesicles (e) and membranes (f) within the CD87⁺ cultures. Green label corresponds to GFP as detected by immunostaining. DAPI staining is shown in blue. (g) Fluorescence photomicrograph of Ac-LDL uptake (red) revealed positive signal only in CD87⁺ cells. Scale bars, 25 μm.