Complement component 3a receptor (C3aR) (C3aR)

The Complement component 3a receptor (C3aR) is a G protein-coupled receptor (GPCR) that mediates the biological effects of the anaphylatoxin C3a, a peptide fragment generated during complement system activation (UniProt: Q16581). C3aR is widely expressed on myeloid cells, including neutrophils, macrophages, and mast cells, as well as on non-immune cells like endothelial and epithelial cells (PubMed: 29097965). Upon binding of C3a, the receptor triggers intracellular signaling pathways, such as PLC/IP3 and MAPK, leading to pro-inflammatory responses including chemotaxis, vasodilation, and the release of inflammatory cytokines and histamine (StatPearls: Complement System). The C3a-C3aR axis is critically involved in the pathogenesis of various inflammatory and autoimmune disorders, such as asthma, sepsis, and rheumatoid arthritis, where overactivation leads to tissue damage (PubMed: 30100811). Consequently, C3aR is a significant therapeutic target, with research focusing on small-molecule antagonists or upstream inhibitors of C3 cleavage to mitigate excessive inflammation in these disease states (NCBI: NBK534868).

Other names

C3AR1C3a anaphylatoxin receptorComplement component 3a receptor 1AZL1

Antagonism of the G protein-coupled receptor to block pro-inflammatory signaling induced by the anaphylatoxin C3a, or inhibition of C3 cleavage to prevent C3a formation.