Figure 1.

Nonuniform CD73 expression in the MSC pool. Two subsets of isolated pMSC were found upon the intensity of the CD73 expression, nearly one-third of the population with a high expression of CD73 and the rest with a low expression (a). Nonuniform aspect of the CD73 expression was also found in MSC from the bone marrow (bMSC), subcutaneous adipose (aMSC), and human umbilical cord blood (ucMSC) (b). By using FACS separation, expression of CD73 at a high level (CD73^high pMSC) and expression of CD73 at a low level (CD73^low pMSC) constitute a fivefold difference according to fluorescence intensity (c) and eightfold at the mRNA level (d). Both subsets of pMSC showed a typical cobblestone morphology and had similar population-doubling time (e) and identical potential in osteogenic, adipogenic, and myogenic differentiation (f). Bar = 50 μm in (a), 20 μm in (c), and 100 μm in (e) and (f). ^∗∗ indicates p < 0.01.