Phenotypic and functional characterization of a marrow-derived stromal cell line, M210B4 and its comparison with primary marrow stromal cells

In vitro co-culture system consisting of bone marrow stromal cells (BMSCs) or mesenchymal stromal cell lines of marrow origin has provided important clues about the regulation of hematopoietic stem cells (HSCs) by their microenvironment or niche. In the current studies, we have compared phenotypic and functional characters of a marrow-derived mesenchymal stem cell line, M210B4, with BMSCs. We demonstrate that M210B4 resembles BMSCs in terms of phenotypic characters. Unlike the BMSCs, M210B4 differentiated only towards adipogenic lineage, and was refractory towards osteogenic differentiation. However, M210B4 cells exhibited a higher HSC-supportive ability as assessed by flow cytometry analyses of the output cells from co-cultures. We observed that M210B4 cells show a constitutively higher activation of p44/42 and p38 MAPK pathways compared to BMSCs, contributing to their higher HSC-support in vitro. Overall, the results show that M210B4 forms a suitable in vitro system to study HSC regulation in vitro.