Colonic mucosal macrophage (LpM)

Colonic mucosal macrophages (LpMs) are a specialized population of myeloid-derived immune cells residing in the lamina propria of the large intestine, primarily replenished by circulating Ly6C+ monocytes [1, 18, 21]. They are essential for maintaining intestinal homeostasis by performing 'inflammatory anergy,' which involves the phagocytosis of commensal bacteria and apoptotic debris without triggering a pro-inflammatory response [4, 9]. In pathological states such as Inflammatory Bowel Disease (IBD), these cells shift toward a pro-inflammatory (M1-like) phenotype, secreting high levels of cytokines like TNF-α, IL-1β, and IL-6 that drive mucosal damage [1, 5, 8]. They also function as tumor-associated macrophages (TAMs) in colorectal cancer, where they can promote immunosuppression, angiogenesis, and metastasis [5, 14]. Therapeutic strategies targeting these macrophages include the use of aminosalicylates like mesalamine to induce M2 polarization, CSF1R inhibitors to deplete pro-tumorigenic subsets, and nanovesicle-based delivery systems to localize anti-inflammatory drugs to the inflamed mucosa [6, 10, 14]. However, targeting these cells carries risks such as increased susceptibility to enteric infections and impaired tissue repair [1, 16]. Overall, they represent a critical cellular target for modulating the gut immune microenvironment in chronic inflammatory and neoplastic diseases [1, 3].

Other names

Intestinal macrophageLamina propria macrophageGut-associated macrophageColonic macrophage

Macrophage polarization modulation, depletion of pro-inflammatory subsets, and inhibition of cytokine signaling