Pharmacologic profile of OC000459, a potent, selective, and orally active D prostanoid receptor 2 antagonist that inhibits mast cell-dependent activation of T helper 2 lymphocytes and eosinophils.

D prostanoid receptor 2 (DP2) [also known as chemoattractant receptor-homologous molecule expressed on T helper 2 (Th2) cells (CRTH2)] is selectively expressed by Th2 lymphocytes, eosinophils, and basophils and mediates recruitment and activation of these cell types in response to prostaglandin D2 (PGD2). (5-Fluoro-2-methyl-3-quinolin-2-ylmethylindo-1-yl)-acetic acid (OC000459) is an indole-acetic acid derivative that potently displaces [³H]PGD2 from human recombinant DP2 (K(i) = 0.013 µM), rat recombinant DP2 (K(i) = 0.003 µM), and human native DP2 (Th2 cell membranes; K(i) = 0.004 µM) but does not interfere with the ligand binding properties or functional activities of other prostanoid receptors (prostaglandin E1₋4 receptors, D prostanoid receptor 1, thromboxane receptor, prostacyclin receptor, and prostaglandin F receptor). OC000459 inhibited chemotaxis (IC50 = 0.028 µM) of human Th2 lymphocytes and cytokine production (IC50 = 0.019 µM) by human Th2 lymphocytes. OC000459 competitively antagonized eosinophil shape change responses induced by PGD2 in both isolated human leukocytes (pK(B) = 7.9) and human whole blood (pK(B) = 7.5) but did not inhibit responses to eotaxin, 5-oxo-eicosatetraenoic acid, or complement component C5a. OC000459 also inhibited the activation of Th2 cells and eosinophils in response to supernatants from IgE/anti-IgE-activated human mast cells. OC000459 had no significant inhibitory activity on a battery of 69 receptors and 19 enzymes including cyclooxygenase 1 (COX1) and COX2. OC000459 was found to be orally bioavailable in rats and effective in inhibiting blood eosinophilia induced by 13,14-dihydro-15-keto-PGD2 (DK-PGD2) in this species (ED50 = 0.04 mg/kg p.o.) and airway eosinophilia in response to an aerosol of DK-PGD2 in guinea pigs (ED50 = 0.01 mg/kg p.o.). These data indicate that OC000459 is a potent, selective, and orally active DP2 antagonist that retains activity in human whole blood and inhibits mast cell-dependent activation of both human Th2 lymphocytes and eosinophils.

Cannabinoid signalling in TNF-alpha induced IL-8 release.

The molecular events mediating the immunomodulatory properties of cannabinoids have remained largely unresolved. We have therefore investigated the molecular mechanism(s) through which R-(+)-[2,3-dihydro-5-methyl-3-[(morpholinyl)methyl] pyrrolo[1,2,3-de]-1,4-benzoxazinyl]-(1-napthanlenyl) methanone (WIN55212-2) modulate production of interleukin-8 (IL-8) in HT-29 cells. Release of IL-8 induced by tumor necrosis factor-alpha (TNF-alpha) was determined by enzyme-linked immunosorbent assay (ELISA). Changes in expression of inhibitory kappa B (IkappaB) were monitored by Western blotting and activation of nuclear factor-kappa B (NF-kappaB) was determined in electrophoretic mobility shift assay (EMSAs). TNF-alpha induced release of IL-8 was inhibited by WIN55212-2 which also blocked the degradation of IkappaB-alpha and activation of NF-kappaB induced by TNF-alpha. These data provide strong evidence that WIN55212-2 may modulate IL-8 release by negatively regulating the signaling cascade leading to the activation of NF-kappaB. These findings highlight a potential mechanism for the immunomodulatory properties of cannabinoids and contribute towards acquiring a clear understanding of the role of cannabinoids in inflammation.

The Journal of Inflammation.

Welcome to the Journal of Inflammation, the first open-access, peer-reviewed, online journal to focus on all aspects of the study of inflammation and inflammatory conditions. While research into inflammation has resulted in great progress in the latter half of the 20th century, the rate of progress is rapidly accelerating. Thus there is a need for a vehicle through which this very diverse research can be made readily available to the scientific community. The Journal of Inflammation, a peer reviewed journal, provides the ideal vehicle for such rapid dissemination of information. The Journal of Inflammation covers the full range of underlying cellular and molecular mechanisms involved, not only in the production of the inflammatory responses but, more importantly in clinical terms, in the healing process as well. This includes molecular, cellular, animal and clinical studies related to the study of inflammatory conditions and responses, and all related aspects of pharmacology, such as anti-inflammatory drug development, trials and therapeutic developments, etc. All articles published in the Journal of Inflammation are immediately listed in PubMed, and access to published articles is universal and free through the internet.