Mouse Macrophage Colony-Stimulating Factor (M-CSF) is a cytokine that regulates the development, proliferation, and survival of monocytes and macrophages in mice (Mus musculus). M-CSF is produced by several cell types, including fibroblasts, endothelial cells, epithelial cells, and stromal cells, in response to tissue signals and inflammatory stimuli. Mouse M-CSF binds to the colony-stimulating factor-1 receptor (CSF1R), a receptor tyrosine kinase expressed on monocytes and macrophage lineage cells, activating intracellular signaling pathways such as PI3K–AKT, ERK/MAPK, and JAK–STAT that promote differentiation and maintenance of macrophage populations. Through these mechanisms, M-CSF supports macrophage-mediated immune surveillance, phagocytosis, tissue homeostasis, and inflammatory responses. Because macrophages play a central role in host defense and immune regulation, M-CSF–mediated macrophage function is essential for maintaining immune health and responding to infection or tissue injury in mice. In cell culture, recombinant mouse M-CSF is commonly used to promote differentiation of mouse monocytes or bone marrow–derived cells into macrophages and to support macrophage proliferation and functional assays in vitro. Mouse M-CSF is also widely used in murine animal models of infectious disease, inflammation, cancer, and metabolic disorders to study macrophage biology and immune regulation.