title: Biochemical, functional, and pharmacological characterization of AT-56, an orally active and selective inhibitor of lipocalin-type prostaglandin D synthase.
abstract: We report here that 4-dibenzo[a,d]cyclohepten-5-ylidene-1-[4-(2H-tetrazol-5-yl)-butyl]-piperidine (AT-56) is an orally active and selective inhibitor of lipocalin-type prostaglandin (PG) D synthase (L-PGDS). AT-56 inhibited human and mouse L-PGDSs in a concentration (3-250 microm)-dependent manner but did not affect the activities of hematopoietic PGD synthase (H-PGDS), cyclooxygenase-1 and -2, and microsomal PGE synthase-1. AT-56 inhibited the L-PGDS activity in a competitive manner against the substrate PGH(2) (K(m) = 14 microm) with a K(i) value of 75 microm but did not inhibit the binding of 13-cis-retinoic acid, a nonsubstrate lipophilic ligand, to L-PGDS. NMR titration analysis revealed that AT-56 occupied the catalytic pocket, but not the retinoid-binding pocket, of L-PGDS. AT-56 inhibited the production of PGD(2) by L-PGDS-expressing human TE-671 cells after stimulation with Ca(2+) ionophore (5 microm A23187) with an IC(50) value of about 3 microm without affecting their production of PGE(2) and PGF(2alpha) but had no effect on the PGD(2) production by H-PGDS-expressing human megakaryocytes. Orally administered AT-56 (<30 mg/kg body weight) decreased the PGD(2) production to 40% in the brain of H-PGDS-deficient mice after a stab wound injury in a dose-dependent manner without affecting the production of PGE(2) and PGF(2alpha) and also suppressed the accumulation of eosinophils and monocytes in the bronco-alveolar lavage fluid from the antigen-induced lung inflammation model of human L-PGDS-transgenic mice.
authors.affiliation: Department of Molecular Behavioral Biology, Osaka Bioscience Institute, 6-2-4 Furuedai, Suita, Osaka 565-0874, Japan.
authors.forename: Daisuke
authors.initials: D
authors.lastname: Irikura
authors.forename: Kosuke
authors.initials: K
authors.lastname: Aritake
authors.forename: Nanae
authors.initials: N
authors.lastname: Nagata
authors.forename: Toshihiko
authors.initials: T
authors.lastname: Maruyama
authors.forename: Shigeru
authors.initials: S
authors.lastname: Shimamoto
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Urade
mesh_terms: D000284:Administration, Oral; D000818:Animals; D000001:Calcimycin / Q000494:pharmacology; D051545:Cyclooxygenase 1 / Q000235:genetics / Q000378:metabolism; D051546:Cyclooxygenase 2 / Q000235:genetics / Q000378:metabolism; D015237:Dinoprost / Q000096:biosynthesis; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D004353:Drug Evaluation, Preclinical; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D004804:Eosinophils / Q000201:enzymology; D006801:Humans; D019746:Intramolecular Oxidoreductases / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism*; D007476:Ionophores / Q000494:pharmacology; D054834:Lipocalins / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism*; D008297:Male; D008533:Megakaryocytes / Q000201:enzymology; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism; D051379:Mice; D018345:Mice, Knockout; D009000:Monocytes / Q000201:enzymology; D011014:Pneumonia / Q000188:drug therapy / Q000201:enzymology* / Q000378:metabolism; D015230:Prostaglandin D2 / Q000096:biosynthesis; D014945:Wound Healing / Q000187:drug effects*; D014951:Wounds, Stab / Q000188:drug therapy / Q000201:enzymology* / Q000235:genetics
chemical_list: D004791:Enzyme Inhibitors; D007476:Ionophores; D054834:Lipocalins; D008565:Membrane Proteins; D000001:Calcimycin; D015237:Dinoprost; C077623:Ptgs2 protein, mouse; D051545:Cyclooxygenase 1; D051546:Cyclooxygenase 2; C496511:PTGS1 protein, human; C496540:PTGS2 protein, human; C496512:Ptgs1 protein, mouse; D019746:Intramolecular Oxidoreductases; C022466:prostaglandin R2 D-isomerase; D015230:Prostaglandin D2