Gene expression profile of murine bone marrow endosteal populations (2). Mus musculus

A subset of osteoblasts functions as a key component of the hematopoietic stem cell niche. But it is still unclear that the precise cellular and molecular contribution of endosteal cell populations on the HSC supportive microenvironment. We purified the endosteal cells and subdivided them into mesenchymal progenitor cells (MPCs: PDGF-Ra(+)Sca-1(+)) and two osteoblast populations (PDGF-Ra(-)Sca-1(-) and PDGF-Ra(+)Sca-1(-)). In this study, to clarify the characteristics of these fractionated cells in detail, gene expression analysis were performed using the GeneChip Mouse Genome Array 430 2.0 (Affymetrix). Overall design: The bone fragments of femur and tibiae were treated with collagenase and endosteal cells were obtained. For enrichment of non-hematopoietic and non-endothelial population, CD45(-)CD31(-)Ter119(-) population was isolated and then the expressions of Sca-1 and PDGF-Ra was analyzed by FACS. FACS analysis showed that CD45(-)CD31(-)Ter119(-) cells were subdivided into PDGF-Ra(+)Sca-1(+), PDGF-Ra(-)Sca-1(-) and PDGF-Ra(+)Sca-1(-). These three populations were sorted and RNA samples were used for amplification, labeling, and hybridization to independent arrays.