title: Inhibition of RICK/nuclear factor-kappaB and p38 signaling attenuates the inflammatory response in a murine model of Crohn disease.
abstract: Nuclear factor-kappaB (NF-kappaB) is the main target of anti-inflammatory therapies in human chronic inflammatory bowel diseases (IBD), Crohn disease, and ulcerative colitis. This study investigates the molecular anti-inflammatory mechanisms of SB203580, an inhibitor of the mitogen-activated protein kinase p38. The murine trinitrobenzene sulfonic acid (TNBS)-induced colitis was used as an established model of human Crohn disease. Here we show that SB203580 improved the clinical condition, reduced intestinal inflammation, and suppressed mRNA levels of pro-inflammatory cytokines elevated upon induction of colitis. Besides p38 kinase activity, the "classical" IkappaB-dependent NF-kappaB pathway was strongly up-regulated during colitis induction, whereas the "alternative" was not. SB203580 treatment resulted in a drastic down-regulation of p38 and NF-kappaB activity. The molecular analysis of NF-kappaB activation revealed that Rip-like interacting caspase-like apoptosis-regulatory protein kinase (RICK), a key component of a pathway leading to NF-kappaB induction, is also strongly inhibited by SB203580. In contrast, SB203580 had no effect on the colitis-induced activation of other potential NF-kappaB-activating kinases such as protein kinase C (PKC), mixed lineage kinase 3, and the oncogene product Cot/TPL2. Thus, the inhibitory effect of SB203580 on NF-kappaB activation is to a large extent mediated by RICK inhibition. RICK is the effector kinase of the intracellular receptor of bacterial peptidoglycan NOD. Because bacterial products are suggested to be the key pathogenic agents triggering IBD, inhibition of the NOD/RICK pathway may serve as a novel target of future therapies in human IBD.
authors.affiliation: Institute of Experimental Internal Medicine, Department of Gastroenterology, Hepatology and Infectiology, Otto-von-Guericke-University, Magdeburg D-39120, Germany.
authors.forename: Eike
authors.initials: E
authors.lastname: Hollenbach
authors.forename: Michael
authors.initials: M
authors.lastname: Vieth
authors.forename: Albert
authors.initials: A
authors.lastname: Roessner
authors.forename: Manfred
authors.initials: M
authors.lastname: Neumann
authors.forename: Peter
authors.initials: P
authors.lastname: Malfertheiner
authors.forename: Michael
authors.initials: M
authors.lastname: Naumann
mesh_terms: D000818:Animals; D003424:Crohn Disease / Q000201:enzymology* / Q000378:metabolism; D016207:Cytokines / Q000378:metabolism; D004195:Disease Models, Animal; D004591:Electrophoresis, Polyacrylamide Gel; D004789:Enzyme Activation; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005260:Female; D007093:Imidazoles / Q000494:pharmacology; D015151:Immunoblotting; D007249:Inflammation / Q000201:enzymology*; D051379:Mice; D008807:Mice, Inbred BALB C; D008856:Microscopy, Fluorescence; D008954:Models, Biological; D016328:NF-kappa B / Q000037:antagonists & inhibitors*; D011494:Protein Kinases / Q000378:metabolism*; D011725:Pyridines / Q000494:pharmacology; D053475:Receptor-Interacting Protein Serine-Threonine Kinase 2; D053422:Receptor-Interacting Protein Serine-Threonine Kinases; D013347:Subcellular Fractions / Q000378:metabolism; D014302:Trinitrobenzenesulfonic Acid / Q000494:pharmacology; D015854:Up-Regulation; D048051:p38 Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors* / Q000378:metabolism
chemical_list: D016207:Cytokines; D004791:Enzyme Inhibitors; D007093:Imidazoles; D016328:NF-kappa B; D011725:Pyridines; D014302:Trinitrobenzenesulfonic Acid; D011494:Protein Kinases; C506253:RIPK2 protein, human; D053475:Receptor-Interacting Protein Serine-Threonine Kinase 2; D053422:Receptor-Interacting Protein Serine-Threonine Kinases; C506255:Ripk2 protein, mouse; D048051:p38 Mitogen-Activated Protein Kinases; C093642:SB 203580