CSF1

CSF1 Full Name

colony stimulating factor 1 (macrophage)

CSF1 Introduction

Colony stimulating factor 1 (CSF1), also known as macrophage colony-stimulating factor, is a secreted glycoprotein cytokine that plays a central role in regulating the survival, proliferation, and differentiation of mononuclear phagocytes. Structurally, CSF1 functions as an 85 kDa homodimer composed of two 43 kDa monomers and belongs to the hematopoietic growth factor family. Despite moderate transcript-level homology between human and mouse CSF1 (~60%), its biologically active N-terminal region is highly conserved (~80% amino acid similarity), reflecting its essential evolutionary role in immune regulation. For researchers and clinicians, one of the key challenges in targeting CSF1 lies in its pleiotropic nature: it is not merely an inflammatory mediator, but also a critical regulator of tissue-resident macrophages such as microglia in the central nervous system, where it supports neuronal health, synaptic pruning, neurotrophic signaling, and neural circuit maintenance. This dual functionality makes CSF1 a molecule of high biological importance but also of therapeutic complexity, especially in systems where immune balance is tightly controlled.

Functionally, CSF1 acts through the CSF1 receptor (CSF1R) to orchestrate the development and homeostasis of macrophage-lineage cells across multiple tissues. In the central nervous system, CSF1-driven microglial activity is essential for maintaining homeostasis, but dysregulation of this pathway can shift microglia from protective to pathogenic states, contributing to neuroinflammation and neurodegeneration. Recent evidence highlights CSF1 as a molecular switch that can influence whether microglia act as "friends or foes" in disease progression, particularly in chronic neurodegenerative conditions. Beyond the nervous system, CSF1 is increasingly recognized as a key regulator of inflammatory signaling networks in peripheral tissues, where it modulates cytokine production and apoptosis-related pathways. Its ability to integrate immune signaling with tissue remodeling makes it a critical node in both physiological repair and pathological inflammation, yet also raises the challenge of balancing therapeutic inhibition without disrupting essential immune functions.

Clinically, CSF1 has been implicated in a wide spectrum of human diseases, particularly those driven by chronic inflammation and immune microenvironment dysregulation. In cancer, CSF1 is frequently overexpressed and contributes to the recruitment and polarization of tumor-associated macrophages toward immunosuppressive M2-like phenotypes, thereby promoting tumor growth, invasion, and metastasis. Blocking the CSF1/CSF1R axis has been shown to reprogram the tumor microenvironment into a more immune-permissive state, enhancing CD8+ T cell responses and improving the efficacy of immunotherapies such as PD-L1 blockade and cancer vaccines. In non-oncological conditions, CSF1 has been linked to intervertebral disc degeneration, where its inhibition reduces inflammatory protein expression and cell apoptosis, suggesting its role as a potential biomarker and therapeutic target. Additionally, dysregulated CSF1 signaling has been observed in reproductive disorders such as polycystic ovary syndrome, where it contributes to granulosa cell ferroptosis through miRNA-regulated pathways. Collectively, these findings position CSF1 as a high-value but context-dependent therapeutic target, where disease-specific modulation rather than complete suppression may be essential for effective clinical translation.

Alternate Names for CSF1

CSF1; colony stimulating factor 1 (macrophage); MCSF; CSF-1; macrophage colony-stimulating factor 1; lanimostim;

• 1.Wiens KR, et al.; Diversity of Microglia-Derived Molecules with Neurotrophic Properties That Support Neurons in the Central Nervous System and Other Tissues. Molecules. 2024, 29(23):5525.
  2.Maldonado MDM, et al.; Blockade of tumor-derived colony-stimulating factor 1 (CSF1) promotes an immune-permissive tumor microenvironment. Cancer Immunol Immunother. 2023 , 72(10):3349-3362.