Possible novel receptor for PGD2 on human bronchial epithelial cells

Prostaglandin D(2) (PGD(2)), a major prostanoid produced by activated mast cells, has long been implicated in allergic diseases. Recent studies have shown that PGD(2) exerts its effects through two different G-protein-coupled receptors (GPCRs), the D-prostanoid receptor (DP) and the chemoattractant receptor-homologous molecule expressed on T helper type-2 cells (CRTH2), expressed in various human tissues. The PGD(2)/CRTH2 system mediates the chemotaxis of eosinophils, basophils, and Th2 cells, which are involved in the induction of allergic inflammation. We have reported that normal human bronchial epithelial cells (NHBE) and epithelial cell lines (NCI-H(292)) expressed CRTH2, and PGD(2) induces production of IL-8 and GM-CSF. This review discusses the role of CRTH2/DP on epithelial cells and mentions a possible novel receptor for PGD(2).