title: Modulation of lipopolysaccharide-induced neuronal response by activation of the enteric nervous system.
abstract: BACKGROUND
  Evidence continues to mount concerning the importance of the enteric nervous system (ENS) in controlling numerous intestinal functions in addition to motility and epithelial functions. Nevertheless, little is known concerning the direct participation of the ENS in the inflammatory response of the gut during infectious or inflammatory insults. In the present study we analyzed the ENS response to bacterial lipopolysaccharide, in particular the production of a major proinflammatory cytokine, tumor necrosis factor-alpha (TNF-α).
  
  
  METHODS
  TNF-α expression (measured by qPCR, quantitative Polymerase Chain Reaction) and production (measured by ELISA) were measured in human longitudinal muscle-myenteric plexus (LMMP) and rat ENS primary cultures (rENSpc). They were either treated or not treated with lipopolysaccharide (LPS) in the presence or not of electrical field stimulation (EFS). Activation of extracellular signal-regulated kinase (ERK) and 5'-adenosine monophosphate-activated protein kinase (AMPK) pathways was analyzed by immunocytochemistry and Western blot analysis. Their implications were studied using specific inhibitors (U0126, mitogen-activated protein kinase kinase, MEK, inhibitor and C compound, AMPK inhibitor). We also analyzed toll-like receptor 2 (TLR2) expression and interleukin-6 (IL-6) production after LPS treatment simultaneously with EFS or TNF-α-neutralizing antibody.
  
  
  RESULTS
  Treatment of human LMMP or rENSpc with LPS induced an increase in TNF-α production. Activation of the ENS by EFS significantly inhibited TNF-α production. This regulation occurred at the transcriptional level. Signaling analyses showed that LPS induced activation of ERK but not AMPK, which was constitutively activated in rENSpc neurons. Both U0126 and C compound almost completely prevented LPS-induced TNF-α production. In the presence of LPS, EFS inhibited the ERK and AMPK pathways. In addition, we demonstrated using TNF-α-neutralizing antibody that LPS-induced TNF-α production increased TLR2 expression and reduced IL-6 production.
  
  
  CONCLUSIONS
  Our results show that LPS induced TNF-α production by enteric neurons through activation of the canonical ERK pathway and also in an AMPK-dependent manner. ENS activation through the inhibition of these pathways decreased TNF-α production, thereby modulating the inflammatory response induced by endotoxin.
authors.affiliation: Neuropathies of the enteric nervous system and digestive diseases, INSERM UMR913, School of Medicine, University of Nantes, 1, rue Gaston Veil, Nantes, F-44035, France. sabrina.coquenlorge@univ-nantes.fr.|University of Nantes, 1 quai de Tourville, BP 13522, Nantes, Cedex 1, F-44035, France. sabrina.coquenlorge@univ-nantes.fr.|Institut des Maladies de l'Appareil Digestif, Centre Hospitalier Universitaire, Nantes, Hopital Hôtel-Dieu, 1 place Alexis Ricordeau, Nantes, F-44093, France. sabrina.coquenlorge@univ-nantes.fr.|Centre de Recherche en Nutrition Humaine, Hopital Hôtel-Dieu, 1 place Alexis Ricordeau, Nantes, F-44093, France. sabrina.coquenlorge@univ-nantes.fr.
authors.forename: Sabrina
authors.initials: S
authors.lastname: Coquenlorge
authors.affiliation: Neuropathies of the enteric nervous system and digestive diseases, INSERM UMR913, School of Medicine, University of Nantes, 1, rue Gaston Veil, Nantes, F-44035, France. emilie.duchalais@gmail.com.|University of Nantes, 1 quai de Tourville, BP 13522, Nantes, Cedex 1, F-44035, France. emilie.duchalais@gmail.com.|Institut des Maladies de l'Appareil Digestif, Centre Hospitalier Universitaire, Nantes, Hopital Hôtel-Dieu, 1 place Alexis Ricordeau, Nantes, F-44093, France. emilie.duchalais@gmail.com.|Centre de Recherche en Nutrition Humaine, Hopital Hôtel-Dieu, 1 place Alexis Ricordeau, Nantes, F-44093, France. emilie.duchalais@gmail.com.
authors.forename: Emilie
authors.initials: E
authors.lastname: Duchalais
authors.affiliation: Neuropathies of the enteric nervous system and digestive diseases, INSERM UMR913, School of Medicine, University of Nantes, 1, rue Gaston Veil, Nantes, F-44035, France. julien.chevalier@univ-nantes.fr.|University of Nantes, 1 quai de Tourville, BP 13522, Nantes, Cedex 1, F-44035, France. julien.chevalier@univ-nantes.fr.|Institut des Maladies de l'Appareil Digestif, Centre Hospitalier Universitaire, Nantes, Hopital Hôtel-Dieu, 1 place Alexis Ricordeau, Nantes, F-44093, France. julien.chevalier@univ-nantes.fr.|Centre de Recherche en Nutrition Humaine, Hopital Hôtel-Dieu, 1 place Alexis Ricordeau, Nantes, F-44093, France. julien.chevalier@univ-nantes.fr.
authors.forename: Julien
authors.initials: J
authors.lastname: Chevalier
authors.affiliation: Neuropathies of the enteric nervous system and digestive diseases, INSERM UMR913, School of Medicine, University of Nantes, 1, rue Gaston Veil, Nantes, F-44035, France. francois.cossais@mri.bund.de.|University of Nantes, 1 quai de Tourville, BP 13522, Nantes, Cedex 1, F-44035, France. francois.cossais@mri.bund.de.|Institut des Maladies de l'Appareil Digestif, Centre Hospitalier Universitaire, Nantes, Hopital Hôtel-Dieu, 1 place Alexis Ricordeau, Nantes, F-44093, France. francois.cossais@mri.bund.de.|Centre de Recherche en Nutrition Humaine, Hopital Hôtel-Dieu, 1 place Alexis Ricordeau, Nantes, F-44093, France. francois.cossais@mri.bund.de.
authors.forename: Francois
authors.initials: F
authors.lastname: Cossais
authors.affiliation: Neuropathies of the enteric nervous system and digestive diseases, INSERM UMR913, School of Medicine, University of Nantes, 1, rue Gaston Veil, Nantes, F-44035, France. malvyne.derkinderen@univ-nantes.fr.|University of Nantes, 1 quai de Tourville, BP 13522, Nantes, Cedex 1, F-44035, France. malvyne.derkinderen@univ-nantes.fr.|Institut des Maladies de l'Appareil Digestif, Centre Hospitalier Universitaire, Nantes, Hopital Hôtel-Dieu, 1 place Alexis Ricordeau, Nantes, F-44093, France. malvyne.derkinderen@univ-nantes.fr.|Centre de Recherche en Nutrition Humaine, Hopital Hôtel-Dieu, 1 place Alexis Ricordeau, Nantes, F-44093, France. malvyne.derkinderen@univ-nantes.fr.
authors.forename: Malvyne
authors.initials: M
authors.lastname: Rolli-Derkinderen
authors.affiliation: Neuropathies of the enteric nervous system and digestive diseases, INSERM UMR913, School of Medicine, University of Nantes, 1, rue Gaston Veil, Nantes, F-44035, France. Michel.Neunlist@univ-nantes.fr.|University of Nantes, 1 quai de Tourville, BP 13522, Nantes, Cedex 1, F-44035, France. Michel.Neunlist@univ-nantes.fr.|Institut des Maladies de l'Appareil Digestif, Centre Hospitalier Universitaire, Nantes, Hopital Hôtel-Dieu, 1 place Alexis Ricordeau, Nantes, F-44093, France. Michel.Neunlist@univ-nantes.fr.|Centre de Recherche en Nutrition Humaine, Hopital Hôtel-Dieu, 1 place Alexis Ricordeau, Nantes, F-44093, France. Michel.Neunlist@univ-nantes.fr.
authors.forename: Michel
authors.initials: M
authors.lastname: Neunlist
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D017615:Enteric Nervous System / Q000187:drug effects / Q000378:metabolism*; D006801:Humans; D018836:Inflammation Mediators / Q000378:metabolism*; D008070:Lipopolysaccharides / Q000633:toxicity*; D009474:Neurons / Q000187:drug effects / Q000378:metabolism*; D009924:Organ Culture Techniques; D051381:Rats; D017207:Rats, Sprague-Dawley; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis
chemical_list: D018836:Inflammation Mediators; D008070:Lipopolysaccharides; D014409:Tumor Necrosis Factor-alpha