9α,11β-PGF2 and its stereoisomer PGF2α are novel agonists of the chemoattractant receptor, CRTH2

CRTH2 is a recently described chemoattractant receptor for the prostaglandin, PGD2, expressed by Th2 cells, eosinophils and basophils, and believed to play a role in allergic inflammation. Here we describe the potency of several PGD2 metabolites at the receptor to induce cell migration and activation. We report for the first time that the PGD2 metabolite, 9α,11β-PGF2, and its stereoisomer, PGF2α, are CRTH2 agonists. 9α,11β-PGF2 is a major metabolite produced in vivo following allergen challenge, whilst PGF2α is generated independently of PGD synthetase, with implications for CRTH2 signalling in the presence or absence of PGD2 production.