Origin of endothelial progenitors in human postnatal bone marrow
J. Clin. Invest. Morayma Reyes, et al. 109:337 doi:10.1172/JCI14327 [Go to this article.]

Figure 5
Further functional characterization of MAPC-derived endothelial cells. (a) Hypoxia upregulates Flk1 and Tek expression on MAPC-derived endothelial cells. MAPC-derived endothelial cells (after 30 population doublings; donor age, 33 years) were incubated at 37°C in 20% or 10% O₂ for 24 hours. Cells were recovered by trypsinization and stained with Ab’s against Flk 1, Tek, and IgG control, and were analyzed by flow cytometry. Plots show isotype control IgG staining profile (thin line) versus specific Ab staining profile (thick line). Representative example of more than three experiments from three donors. Number above plots shows mean fluorescence intensity (MFI) for the control IgG staining and the specific Ab staining. (b) Hypoxia upregulates VEGF production by MAPC-derived endothelial cells. MAPCs (after 30 population doublings; donor age, 45 years) and MAPC-derived endothelial cells were incubated at 37°C in 20% or 10% O₂ for 24 hours. Medium was collected, and VEGF levels were measured by ELISA. Results are shown as mean ± SEM of six experiments from three donors. (c) IL-1α induces expression of HLA-DR, a type of HLAclass II antigens and increases expression of adhesion receptors. MAPC-derived endothelial cells (after 40 population doublings, donor age = 31 years) were incubated with 75 ng/ml IL-1α in serum-free medium for 24 hours. Cells were stained with Ab’s against HLA-class I, HLA class II, β2-microglobulin, vWF, CD31, VCAM, CD62E, CD62P, or control Ab’s, and analyzed using FACS. Plots show isotype control IgG staining profile (thin line) versus specific Ab staining profile (thick line). Representative example of three experiments from three donors. Numbers above each plot show MFI for the control IgG staining and the specific Ab staining. Nl, normal; IL-1 induced populations.