Macrophage M1 polarization state (M1)

Macrophage M1 polarization state refers to the classically activated phenotype of macrophages, which serves as a primary driver of the pro-inflammatory immune response. This state is typically induced by stimuli such as interferon-gamma (IFN-gamma) and microbial components like lipopolysaccharide (LPS), leading to the activation of transcription factors such as STAT1 and NF-kappaB (StatPearls, 2023; Murray, 2017). M1 macrophages are characterized by their ability to produce high levels of pro-inflammatory cytokines (e.g., TNF-alpha, IL-12, IL-6) and reactive oxygen/nitrogen species, which are essential for the destruction of intracellular pathogens and tumor cells (Nature Reviews Immunology, 2016). However, persistent or excessive M1 polarization is associated with the pathogenesis of chronic inflammatory and autoimmune diseases, including rheumatoid arthritis and atherosclerosis. In the context of oncology, many therapeutic strategies aim to repolarize tumor-associated macrophages from an M2-like state to an M1-like state to enhance anti-tumor immunity (Journal of Hematology & Oncology, 2020). Because it represents a complex cellular state rather than a single protein, it is considered a biological process or phenotype rather than a discrete molecular target.

Other names

Classically activated macrophagePro-inflammatory macrophageM1 phenotypeM1 macrophage

Induction of a pro-inflammatory phenotype through the activation of the JAK-STAT1 and TLR4-NF-kappaB signaling pathways (Murray, 2017; StatPearls, 2023).