Peritoneal macrophage (PM)

Peritoneal macrophages are specialized tissue-resident immune cells located within the serous fluid of the peritoneal cavity. They serve as the primary line of defense against abdominal infections and are essential for maintaining local tissue homeostasis through the clearance of apoptotic cells and debris (Gautier et al., 2014). These cells are characterized by the expression of specific markers such as CD11b, F4/80, and the transcription factor GATA6, which regulates their tissue-specific identity and survival (Okabe & Medzhitov, 2014). In humans and mice, they are often divided into two subsets: large peritoneal macrophages (LPMs), which are the long-lived resident population, and small peritoneal macrophages (SPMs), which are derived from blood monocytes during inflammatory events (Ghosn et al., 2010). In disease states, peritoneal macrophages contribute significantly to the progression of endometriosis, post-surgical adhesions, and the formation of the pre-metastatic niche in peritoneal carcinomatosis (Capobianco & Rovere-Querini, 2013). While they are critical players in various pathologies, they represent a heterogeneous cell population rather than a single therapeutic target molecule. Consequently, pharmacological interventions usually aim at specific molecular pathways within these cells, such as the CSF1/CSF1R axis for depletion or various Toll-like receptor (TLR) pathways to modulate their activation state (Etzerodt et al., 2020). Understanding their unique transcriptional profile is vital for developing site-specific therapies that avoid systemic immune disruption.

Other names

Peritoneal MφAbdominal macrophageLarge peritoneal macrophageSmall peritoneal macrophageResident peritoneal macrophage

Not applicable as this entry refers to a cell type rather than a specific molecular target; however, therapeutic modulation typically involves the agonism or antagonism of surface receptors such as CSF1R to deplete populations or TLRs to alter macrophage polarization (Etzerodt et al., 2020).