Complement component 3a receptor 1 (C3aR) (C3aR)

The Complement component 3a receptor 1 (C3aR) is a G protein-coupled receptor (GPCR) that mediates the biological effects of the anaphylatoxin C3a, a peptide fragment generated during the activation of the complement system (UniProt P46089). It is primarily expressed on myeloid cells such as neutrophils, monocytes, and mast cells, but is also found in the central nervous system and on various epithelial and endothelial cells (PubMed: 29038233). Upon binding of C3a, the receptor activates intracellular signaling pathways, including Gq and Gi/o, leading to calcium mobilization, chemotaxis, and the release of proinflammatory cytokines and histamines (IUPHAR/BPS Guide to Pharmacology). C3aR plays a critical role in the pathogenesis of inflammatory and autoimmune diseases, including asthma, rheumatoid arthritis, and lupus, and has been increasingly linked to neuroinflammatory processes in Alzheimer's disease and stroke (PubMed: 30108138). In the context of drug development, recombinant or overexpressed systems—such as HEK293 or CHO cell lines engineered to express human C3aR—are essential for high-throughput screening and the pharmacological evaluation of potential therapeutic agents (PubMed: 15548284). While no C3aR-targeted drugs are currently approved for clinical use, several small-molecule and peptide antagonists, such as SB 290157, are widely used in preclinical research to explore the therapeutic potential of blocking this pathway (PubChem CID 10481849).

Other names

C3AR1AZ3BC3a anaphylatoxin receptorComplement component 3a receptorHNFAG09

Competitive antagonism of the C3a receptor to inhibit downstream proinflammatory signaling pathways mediated by Gq and Gi/o proteins.