title: TRPA1 and substance P mediate colitis in mice.
abstract: OBJECTIVE
  The neuropeptides calcitonin gene-related peptide (CGRP) and substance P, and calcium channels, which control their release from extrinsic sensory neurons, have important roles in experimental colitis. We investigated the mechanisms of colitis in 2 different models, the involvement of the irritant receptor transient receptor potential of the ankyrin type-1 (TRPA1), and the effects of CGRP and substance P.
  
  
  METHODS
  We used calcium-imaging, patch-clamp, and neuropeptide-release assays to evaluate the effects of 2,4,6-trinitrobenzene-sulfonic-acid (TNBS) and dextran-sulfate-sodium-salt on neurons. Colitis was induced in wild-type, knockout, and desensitized mice.
  
  
  RESULTS
  TNBS induced TRPA1-dependent release of colonic substance P and CGRP, influx of Ca2+, and sustained ionic inward currents in colonic sensory neurons and transfected HEK293t cells. Analysis of mutant forms of TRPA1 revealed that TNBS bound covalently to cysteine (and lysine) residues in the cytoplasmic N-terminus. A stable sulfinic acid transformation of the cysteine-SH group, shown by mass spectrometry, might contribute to sustained sensitization of TRPA1. Mice with colitis had increased colonic neuropeptide release, mediated by TRPA1. Endogenous products of inflammatory lipid peroxidation also induced TRPA1-dependent release of colonic neuropeptides; levels of 4-hydroxy-trans-2-nonenal increased in each model of colitis. Colitis induction by TNBS or dextran-sulfate-sodium-salt was inhibited or reduced in TRPA1-/- mice and by 2-(1,3-dimethyl-2,6-dioxo-1,2,3,6-tetrahydro-7H-purin-7-yl)-N-(4-isopro-pylphenyl)-acetamide, a pharmacologic inhibitor of TRPA1. Substance P had a proinflammatory effect that was dominant over CGRP, based on studies of knockout mice. Ablation of extrinsic sensory neurons prevented or attenuated TNBS-induced release of neuropeptides and both forms of colitis.
  
  
  CONCLUSIONS
  Neuroimmune interactions control intestinal inflammation. Activation and sensitization of TRPA1 and release of substance P induce and maintain colitis in mice.
authors.affiliation: Institute of Physiology and Pathophysiology, First Department of Medicine, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany.
authors.forename: Matthias A
authors.initials: MA
authors.lastname: Engel
authors.forename: Andreas
authors.initials: A
authors.lastname: Leffler
authors.forename: Florian
authors.initials: F
authors.lastname: Niedermirtl
authors.forename: Alexandru
authors.initials: A
authors.lastname: Babes
authors.forename: Katharina
authors.initials: K
authors.lastname: Zimmermann
authors.forename: Miloš R
authors.initials: MR
authors.lastname: Filipović
authors.forename: Iwona
authors.initials: I
authors.lastname: Izydorczyk
authors.forename: Mirjam
authors.initials: M
authors.lastname: Eberhardt
authors.forename: Tatjana I
authors.initials: TI
authors.lastname: Kichko
authors.forename: Sonja M
authors.initials: SM
authors.lastname: Mueller-Tribbensee
authors.forename: Mohammad
authors.initials: M
authors.lastname: Khalil
authors.forename: Norbert
authors.initials: N
authors.lastname: Siklosi
authors.forename: Carla
authors.initials: C
authors.lastname: Nau
authors.forename: Ivana
authors.initials: I
authors.lastname: Ivanović-Burmazović
authors.forename: Winfried L
authors.initials: WL
authors.lastname: Neuhuber
authors.forename: Christoph
authors.initials: C
authors.lastname: Becker
authors.forename: Markus F
authors.initials: MF
authors.lastname: Neurath
authors.forename: Peter W
authors.initials: PW
authors.lastname: Reeh
mesh_terms: D000447:Aldehydes / Q000378:metabolism; D000818:Animals; D015740:Calcitonin Gene-Related Peptide / Q000235:genetics / Q000378:metabolism; D002118:Calcium / Q000378:metabolism; D015220:Calcium Channels / Q000235:genetics / Q000378:metabolism; D003092:Colitis / Q000139:chemically induced / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D003106:Colon / Q000187:drug effects / Q000294:innervation / Q000378:metabolism* / Q000473:pathology; D016264:Dextran Sulfate; D004195:Disease Models, Animal; D004224:Diterpenes / Q000494:pharmacology; D005727:Ganglia, Spinal / Q000378:metabolism; D057809:HEK293 Cells; D006801:Humans; D018836:Inflammation Mediators / Q000378:metabolism; D015227:Lipid Peroxidation; D008564:Membrane Potentials; D051379:Mice; D018345:Mice, Knockout; D009154:Mutation; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism; D018408:Patch-Clamp Techniques; D013373:Substance P / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D000074025:TRPA1 Cation Channel; D050916:TRPV Cation Channels / Q000235:genetics / Q000378:metabolism; D014162:Transfection; D050051:Transient Receptor Potential Channels / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D014302:Trinitrobenzenesulfonic Acid
chemical_list: D000447:Aldehydes; D015220:Calcium Channels; D004224:Diterpenes; D018836:Inflammation Mediators; D009419:Nerve Tissue Proteins; D000074025:TRPA1 Cation Channel; C473350:TRPA1 protein, human; D050916:TRPV Cation Channels; C493921:TRPV1 protein, mouse; D050051:Transient Receptor Potential Channels; C475685:Trpa1 protein, mouse; D013373:Substance P; D014302:Trinitrobenzenesulfonic Acid; D016264:Dextran Sulfate; C024353:resiniferatoxin; D015740:Calcitonin Gene-Related Peptide; C027576:4-hydroxy-2-nonenal; D002118:Calcium