VARIATIONS IN CLONAL MARROW STEM CELL LINES ESTABLISHED BY SUBFRACTIONATION CULTURING METHOD WITH MOUSE BONE MARROW

초록

Bone marrow has been considered to contain many different types of progenitor or stem cells. We previously reported a new strategy that provides for the rapid establishment of human clonal marrow stromal/stem cell (hcMSC) lines with a relatively small amount of bone marrow aspirate (Song et al., 2008). The rationale of this method, called subfractionation culturing method (SCM), is that different types of marrow stromal or stem cells can be separated based on their natural cell densities by a series of temporal transfers of the culture supernatant to subsequent dishes where the low density stem cells with high proliferation and differentiation potential may be fractionated. Several different mouse clonal marrow stromal/stem cell (mcMSC) lines were established with mouse bone marrow aspirates of Balb/c, C3H, and C57BL/6 and characterized for their cell surface epitopes, cell proliferation, differentiation potential, and lineage-specific gene expression. The mcMSC lines obtained from these different strains showed a spindle-shape morphology which is very similar to those of the known mouse MSCs. Each mcMSC lines differed in the cell density requirements for optimal cell growth. The overall profiles of the cell surface epitopes of these mcMSC lines were similar to those of the previously known mouse MSCs. However, some mcMSC lines exhibited different expression levels in some epitopes. In addition, the mcMSC lines were capable of differentiating into mesodermal lineages with some differences in differentiation capability. These data suggest that the newly designed protocol, subfractionation culturing method, is an efficient method to establish single-cell derived cMSC lines with mouse bone marrow and some of these mouse cMSC lines possess stem cell characteristics and exhibit differences in cell surface epitopes, expansion capability, and differentiation potential.