Scavenger receptor class A (SR-A) (SR-A)

Class A scavenger receptors (SR-A) are a family of trimeric transmembrane glycoproteins primarily expressed on macrophages and dendritic cells [4, 6]. They are defined by their ability to bind a wide range of polyanionic ligands, most notably modified low-density lipoproteins (LDL) such as oxidized LDL (oxLDL) and acetylated LDL (acLDL) [1, 10]. This binding leads to the unrestricted uptake of lipids and the formation of foam cells, a hallmark of early atherosclerosis [3, 10]. Beyond lipid metabolism, SR-As play critical roles in innate immunity by acting as pattern recognition receptors for bacterial and viral pathogens [9, 21]. They are also involved in cell adhesion, apoptosis, and the polarization of macrophages toward an anti-inflammatory M2 phenotype [6, 31]. In the context of cancer, SR-A1 (MSR1/CD204) is often used as a marker for tumor-associated macrophages, where its expression correlates with poor prognosis in several malignancies [5, 28]. Therapeutic strategies targeting SR-A aim to modulate its activity to treat cardiovascular diseases, chronic inflammation, and cancer, though its multifaceted roles necessitate careful consideration of potential off-target effects on host defense [1, 18].

Other names

Macrophage scavenger receptor 1MSR1CD204SCARA1Macrophage scavenger receptor types I and IISR-AISR-AIISR-AIIIMacrophage receptor with collagenous structure (MARCO)SCARA2Scavenger receptor class A member 3 (SCARA3)Scavenger receptor class A member 4 (SCARA4)Scavenger receptor class A member 5 (SCARA5)

Inhibition of ligand binding to the collagenous domain, modulation of receptor expression, or blocking endocytosis to prevent foam cell formation and inflammatory signaling.