CRTH2

CRTH2, or prostaglandin D2 receptor 2, is a G protein-coupled receptor (GPCR) primarily involved in immune responses and allergic reactions. It is a member of the DP receptor family, which also includes CRTH1, and is encoded by the *PTGDR2* gene located on chromosome 13 in humans. The receptor is expressed on various immune cells, including Th2 cells, eosinophils, basophils, and dendritic cells, playing a key role in mediating inflammation and allergic responses.

Prostaglandin D2 (PGD2), the primary endogenous ligand for CRTH2, is produced by mast cells and other immune cells during allergic reactions. When PGD2 binds to CRTH2, it activates intracellular signaling pathways that promote the release of pro-inflammatory cytokines, such as interleukin-4 (IL-4), interleukin-5 (IL-5), and interleukin-13 (IL-13). These cytokines contribute to the recruitment and activation of other immune cells, exacerbating allergic inflammation.

CRTH2 has been implicated in several allergic and inflammatory diseases, including asthma, allergic rhinitis, and atopic dermatitis. Research suggests that blocking CRTH2 activity may reduce symptoms in these conditions by dampening the immune response. Several pharmaceutical compounds targeting CRTH2 are under investigation as potential therapeutic agents for allergic disorders.

In addition to its role in allergy, CRTH2 has been studied in the context of cancer, where it may influence tumor progression and immune evasion. Further research is needed to fully elucidate its functions and potential as a drug target in various diseases. The receptor’s involvement in multiple immune pathways makes it a promising candidate for immunomodulatory therapies.