title: Prostaglandin D2 mediates neuronal protection via the DP1 receptor.
abstract: Cyclo-oxygenases (COXs) catalyze the first committed step in the synthesis of the prostaglandins PGE(2), PGD(2), PGF(2alpha), PGI(2) and thomboxane A(2). Expression and enzymatic activity of COX-2, the inducible isoform of COX, are observed in several neurological diseases and result in significant neuronal injury. The neurotoxic effect of COX-2 is believed to occur through downstream effects of its prostaglandin products. In this study, we examined the function of PGD(2) and its two receptors DP1 and chemoattractant receptor-homologous molecule expressed on Th2 cells (CRTH2) (DP2) in neuronal survival. PGD(2) is the most abundant prostaglandin in brain and regulates sleep, temperature and nociception. It signals through two distinct G protein-coupled receptors, DP1 and DP2, that have opposing effects on cyclic AMP (cAMP) production. Physiological concentrations of PGD(2) potently and unexpectedly rescued neurons in paradigms of glutamate toxicity in cultured hippocampal neurons and organotypic slices. This effect was mimicked by the DP1-selective agonist BW245C but not by the PGD(2) metabolite 15d-PGJ(2), suggesting that neuroprotection was mediated by the DP1 receptor. Conversely, activation of the DP2 receptor promoted neuronal loss. The protein kinase A inhibitors H89 and KT5720 reversed the protective effect of PGD(2), indicating that PGD(2)-mediated neuroprotection was dependent on cAMP signaling. These studies indicate that activation of the PGD(2) DP1 receptor protects against excitotoxic injury in a cAMP-dependent manner, consistent with recent studies of PGE(2) receptors that also suggest a neuroprotective effect of prostaglandin receptors. Taken together, these data support an emerging and paradoxical neuroprotective role of prostaglandins in the CNS.
authors.affiliation: Department of Neurology, Johns Hopkins University School of Medicine, 600 N. Wolfe Street, Baltimore, MD 21205, USA.
authors.forename: Xibin
authors.initials: X
authors.lastname: Liang
authors.forename: Liejun
authors.initials: L
authors.lastname: Wu
authors.forename: Tracey
authors.initials: T
authors.lastname: Hand
authors.forename: Katrin
authors.initials: K
authors.lastname: Andreasson
mesh_terms: D000818:Animals; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D000242:Cyclic AMP / Q000378:metabolism; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism; D019610:Cytoprotection / Q000187:drug effects / Q000502:physiology; D005260:Female; D006624:Hippocampus / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism*; D006827:Hydantoins / Q000494:pharmacology; D017403:In Situ Hybridization; D019746:Intramolecular Oxidoreductases / Q000235:genetics; D054834:Lipocalins; D009474:Neurons / Q000187:drug effects* / Q000378:metabolism*; D018696:Neuroprotective Agents / Q000494:pharmacology; D015230:Prostaglandin D2 / Q000031:analogs & derivatives* / Q000378:metabolism / Q000494:pharmacology / Q000502:physiology*; D051381:Rats; D011971:Receptors, Immunologic / Q000819:agonists / Q000235:genetics / Q000378:metabolism*; D011982:Receptors, Prostaglandin / Q000819:agonists / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology
chemical_list: C477819:15-deoxyprostaglandin J2; D006827:Hydantoins; D054834:Lipocalins; D018696:Neuroprotective Agents; D011971:Receptors, Immunologic; D011982:Receptors, Prostaglandin; C030669:BW 245C; D000242:Cyclic AMP; D017868:Cyclic AMP-Dependent Protein Kinases; D019746:Intramolecular Oxidoreductases; C022466:prostaglandin R2 D-isomerase; D015230:Prostaglandin D2; C036293:prostaglandin D2 receptor