What is the Colony Stimulating Factor-1 (CSF-1 or M-CSF)?

CSF-1 is the growthfactor for cells of the monocyte-macrophage lineage. Due to the ubiquitousnature of macrophages, CSF-1 has many physiological functions:

·       Hematopoiesis - CSF-1 supports the proliferation,survival and differentiation of cells of the monocyte/macrophage lineage

·       Inflammation - CSF-1 induces macrophages tosecrete cytokines and proteases, thereby enhancing the macrophage’sability to combat microbial infections

·       Bone remodeling – CSF-1 is secreted byosteoblasts and the interaction between CSF-1 and CSF-1R found on earlyosteoclastic progenitors is necessary for their differentiation into matureosteoclasts.  Mice lacking eitherCSF-1 or CSF-1R do not have osteoclasts and develop a disease calledosteopetrosis, characterized by excess bone growth

·       Reproduction – CSF-1 has been suggested toplay a role in trophoblastic growth and embryonic development due to theobservation that during pregnancy CSF-1 is secreted by the uterine epitheliumwith coordinate expression of CSF-1R in the trophoblasts

·       Centralnervous system– CSF-1 is secreted by astrocytes while CSF-1R is expressed in microgliaand neurons in certain parts of the CNS. Recently a role for CSF-1 in brain ischemia has been proposed

·       Cancer – Aberrant expression of CSF-1and CSF-1R has been found in cancers of the breast, ovaries and endometrium,correlating with disease progression and malignancy