BASIC FIBROBLAST GROWTH-FACTOR AND HEMATOPOIESIS

Basic fibroblast growth factor (bFGF or FGF-2) is an angiogenic and pl eiotropic factor involved in the proliferation and differentiation of numerous cell types. It is expressed mostly in tissues of mesoderm and neuroectoderm origin, and plays an important role in the mesoderm ind uction, together with transforming growth factor-beta (TGF-beta). Alth ough hematopoietic cells derive from the mesoderm, relatively few stud ies have addressed the role of bFGF in the hematopoietic system until recently. It appears that bFGF is expressed and produced by bone marro w stromal cells, as well as by cells from several mature peripheral bl ood lineages. It is released and stored in the bone marrow extra-cellu lar matrix. FGF-receptors (FGF-Rs) are expressed on nearly every cell of hematopietic origin tested so far. Growing evidence shows that bFGF can positively regulate hematopoiesis, by acting on various cellular targets: stromal cells, early and committed hematopoietic progenitors, and possibly some mature blood cells. It synergizes with hematopoieti c cytokines, or antagonizes the negative regulatory effects of another factor, TFG-beta, thus potentially playing a central role in hematopo iesis.