The role of granulocyte colony-stimulating factor receptor signaling in neutrophil development

Hematopoiesis or blood cell formation is a strictly regulated process that, in adult individuals, takes place mainly in the bone marrow. All blood cells are derived from a small population of pluripotent stem cells that are capable of self-renewal and differentiation towards distinct lineage-committed progenitor cells. These committed progenitor cells can undergo proliferation followed by terminal differentiation into mature blood cells that include granulocytes, monocytes/macrophages, lymphocytes, erythrocytes, and platelets. Most mature blood cells have a limited life span and need to be replenished constantly. This continuous production is tightly balanced and is regulated essentially by two mechanisms. Stromal cells in the bone marrow affect hematopoiesis by direct cell-to-cell contact and provide a suitable microenvironment required for hematopoietic cell development. In addition, a network of cytokines and hematopoietic growth factors (HGF) specifically control the proliferation, differentiation, survival, and function of different hematopoietic cells. This network is particularly important under stress conditions, such as infection or bleeding, when a rapid rise in specific blood cell types is needed.