title: Decreased MAPK- and PGE2-dependent IL-11 production in Gialpha2-/- colonic myofibroblasts.
abstract: Mice deficient in the G-protein alpha subunit G(i)alpha(2) spontaneously develop colitis and colon cancer. IL-11 is a pleiotropic cytokine known to protect the intestinal epithelium from injury in animal models of colitis and is produced by subepithelial myofibroblasts in response to inflammatory mediators including TGF-beta, IL-1beta, and PGE(2). Arachidonic acid release and subsequent PGE(2) production is significantly decreased in the colonic mucosa of G(i)alpha(2)-/- mice, and we hypothesized that this would affect mucosal IL-11 production. Mucosal levels of IL-11 were found to be significantly decreased in G(i)alpha(2)-/- mice despite the presence of mild colitis. Primary cultures of G(i)alpha(2)-/- intestinal and colonic myofibroblasts (IMF and CMF, respectively) produced less basal and TGF-beta or IL-1beta-stimulated IL-11 mRNA and protein than wild-type cells. Inhibitors of ERK or p38 MAPK activation dose dependently inhibited IMF and CMF IL-11 production in response to TGF-beta stimulation, whereas 16,16 dimethyl-PGE(2) and prostanoid receptor subtype-selective agonists induced IL-11 production. Treatment of animals with the EP4-specific agonist ONO-AE1-329 resulted in enhanced mucosal levels of IL-11, and increased IL-11 production by ex vivo cultured CMF. Modulation of cAMP levels produced diverging results, with enhancement of TGF-beta-induced IL-11 release in IMF pretreated with 8-Br-cAMP and inhibition in cells treated either with pertussis toxin or the PKA inhibitor H-89. These data suggest a physiological role for prostaglandins, MAPK signaling, and cAMP signaling for the production of myofibroblast-derived IL-11 in the mouse intestinal mucosa.
authors.affiliation: Dept. of Pathology, D449 Med Sci I, Univ. of California Irvine, Irvine, CA 92697-4800, USA.
authors.forename: Brian
authors.initials: B
authors.lastname: Hoang
authors.forename: Alice
authors.initials: A
authors.lastname: Trinh
authors.forename: Lutz
authors.initials: L
authors.lastname: Birnbaumer
authors.forename: Robert A
authors.initials: RA
authors.lastname: Edwards
mesh_terms: D015064:16,16-Dimethylprostaglandin E2 / Q000494:pharmacology; D000527:Alprostadil / Q000031:analogs & derivatives / Q000494:pharmacology; D000818:Animals; D002478:Cells, Cultured; D003106:Colon / Q000166:cytology / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism*; D000242:Cyclic AMP / Q000378:metabolism; D015232:Dinoprostone / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D004789:Enzyme Activation; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D005347:Fibroblasts / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism*; D005419:Flavonoids / Q000494:pharmacology; D051960:GTP-Binding Protein alpha Subunit, Gi2 / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D007093:Imidazoles / Q000494:pharmacology; D017370:Interleukin-11 / Q000235:genetics / Q000378:metabolism*; D053583:Interleukin-1beta / Q000378:metabolism; D007421:Intestine, Small / Q000166:cytology / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism*; D008738:Methyl Ethers / Q000494:pharmacology; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D020928:Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D011725:Pyridines / Q000494:pharmacology; D012333:RNA, Messenger / Q000378:metabolism; D018078:Receptors, Prostaglandin E / Q000378:metabolism; D058309:Receptors, Prostaglandin E, EP4 Subtype; D015398:Signal Transduction / Q000187:drug effects; D016212:Transforming Growth Factor beta / Q000378:metabolism; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism
chemical_list: D005419:Flavonoids; D007093:Imidazoles; D017370:Interleukin-11; D053583:Interleukin-1beta; D008738:Methyl Ethers; C461399:ONO-AE1-329; D047428:Protein Kinase Inhibitors; C545651:Ptger4 protein, mouse; D011725:Pyridines; D012333:RNA, Messenger; D018078:Receptors, Prostaglandin E; D058309:Receptors, Prostaglandin E, EP4 Subtype; D016212:Transforming Growth Factor beta; D000242:Cyclic AMP; D048049:Extracellular Signal-Regulated MAP Kinases; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases; D051960:GTP-Binding Protein alpha Subunit, Gi2; C498016:Gnai2 protein, mouse; D000527:Alprostadil; C048491:butaprost; D015232:Dinoprostone; D015064:16,16-Dimethylprostaglandin E2; C093642:SB 203580; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one