Isolation and Analysis of Mesenchymal Progenitors of the Adult Hematopoietic Niche.

Mesenchymal stromal cells are an important component of the adult hematopoietic stem cell niche. They are a diverse population of cells that include a hierarchy of primitive, intermediate, and mature osteoprogenitors that support HSCs and supply the bone with matrix producing osteoblast. To understand the different roles played by individual types of progenitors, it is necessary to separate individual populations and analyze them in a controlled environment. Here we describe two transplantation models, an ectopic bone forming assay and an intravenous injection assay, in which niche components can be isolated and manipulated to dissect their individual properties.