title: EP2 and EP4 receptors on muscularis resident macrophages mediate LPS-induced intestinal dysmotility via iNOS upregulation through cAMP/ERK signals.
abstract: Intestinal resident macrophages play an important role in gastrointestinal dysmotility by producing prostaglandins (PGs) and nitric oxide (NO) in inflammatory conditions. The causal correlation between PGs and NO in gastrointestinal inflammation has not been elucidated. In this study, we examined the possible role of PGE(2) in the LPS-inducible inducible NO synthase (iNOS) gene expression in murine distal ileal tissue and macrophages. Treatment of ileal tissue with LPS increased the iNOS and cyclooxygenase (COX)-2 gene expression, which lead to intestinal dysmotility. However, LPS did not induce the expression of iNOS and COX-2 in tissue from macrophage colony-stimulating factor-deficient op/op mice, indicating that these genes are expressed in intestinal resident macrophages. iNOS and COX-2 protein were also expressed in dextran-phagocytized macrophages in the muscle layer. CAY10404, a COX-2 inhibitor, diminished LPS-dependent iNOS gene upregulation in wild-type mouse ileal tissue and also in RAW264.7 macrophages, indicating that PGs upregulate iNOS gene expression. EP(2) and EP(4) agonists upregulated iNOS gene expression in ileal tissue and isolated resident macrophages. iNOS mRNA induction mediated by LPS was decreased in the ileum isolated from EP(2) or EP(4) knockout mice. In addition, LPS failed to decrease the motility of EP(2) and EP(4) knockout mice ileum. EP(2)- or EP(4)-mediated iNOS expression was attenuated by KT-5720, a PKA inhibitor and PD-98059, an ERK inhibitor. Forskolin or dibutyryl-cAMP mimics upregulation of iNOS gene expression in macrophages. In conclusion, COX-2-derived PGE(2) induces iNOS expression through cAMP/ERK pathways by activating EP(2) and EP(4) receptors in muscularis macrophages. NO produced in muscularis macrophages induces dysmotility during gastrointestinal inflammation.
authors.affiliation: Department of Veterinary Pharmacology, Graduate School of Agriculture and Life Sciences, The University of Tokyo, Japan.
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Tajima
authors.forename: Takahisa
authors.initials: T
authors.lastname: Murata
authors.forename: Kosuke
authors.initials: K
authors.lastname: Aritake
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Urade
authors.forename: Masaki
authors.initials: M
authors.lastname: Michishita
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Matsuoka
authors.forename: Shuh
authors.initials: S
authors.lastname: Narumiya
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Ozaki
authors.forename: Masatoshi
authors.initials: M
authors.lastname: Hori
mesh_terms: D000818:Animals; D002227:Carbazoles; D002460:Cell Line; D051546:Cyclooxygenase 2 / Q000096:biosynthesis; D052246:Cyclooxygenase 2 Inhibitors / Q000494:pharmacology; D015232:Dinoprostone / Q000502:physiology; D005419:Flavonoids; D005769:Gastrointestinal Motility / Q000187:drug effects / Q000502:physiology*; D007082:Ileum / Q000502:physiology; D007555:Isoxazoles / Q000494:pharmacology; D008070:Lipopolysaccharides / Q000494:pharmacology; D008264:Macrophages / Q000378:metabolism*; D008297:Male; D051379:Mice; D052247:Nitric Oxide Synthase Type II / Q000096:biosynthesis*; D011758:Pyrroles; D058307:Receptors, Prostaglandin E, EP2 Subtype / Q000187:drug effects / Q000502:physiology*; D058309:Receptors, Prostaglandin E, EP4 Subtype / Q000187:drug effects / Q000502:physiology*; D013450:Sulfones / Q000494:pharmacology; D015854:Up-Regulation
chemical_list: C501048:3-(4-methylsulfonylphenyl)-4-phenyl-5-trifluoromethylisoxazole; D002227:Carbazoles; D052246:Cyclooxygenase 2 Inhibitors; D005419:Flavonoids; D007555:Isoxazoles; D008070:Lipopolysaccharides; C545651:Ptger4 protein, mouse; D011758:Pyrroles; D058307:Receptors, Prostaglandin E, EP2 Subtype; D058309:Receptors, Prostaglandin E, EP4 Subtype; D013450:Sulfones; C057416:KT 5720; D052247:Nitric Oxide Synthase Type II; C496317:Nos2 protein, mouse; D051546:Cyclooxygenase 2; D015232:Dinoprostone; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one