Regulation of hematopoiesis through adhesion receptors

Normal steady-state hematopoiesis takes place in the bone marrow microenvir onment. Soluble factors as well as contact interactions between the hematop oietic cells and the, marrow microenvironment dictate the fate of hematopoi etic stem cells and progenitors. Over the last decade it has become clear t hat cell-cell and cell-extracellular matrix interactions through adhesion r eceptors play a major role in the hematopoietic process. They are required for the residence of stem cells and progenitors in the marrow, as well as f or homing of stem and progenitor cells to the marrow in the setting of stem cell transplantation. Furthermore, adhesion receptors play an important ro le in regulation of cell behavior, either through direct activation of sign al pathways important for cell survival, cell growth, and cell, fate decisi on-making processes, or by modulating responses to growth factors. Insights in the abnormalities seen in these interactions in diseases of the hematop oietic system will help to develop better therapeutic strategies based on t he pathogenesis of these diseases.