title: Pro-inflammatory and pro-oxidant status of pancreatic islet in vitro is controlled by TLR-4 and HO-1 pathways.
abstract: Since their isolation until implantation, pancreatic islets suffer a major stress leading to the activation of inflammatory reactions. The maintenance of controlled inflammation is essential to preserve survival and function of the graft. Identification and targeting of pathway(s) implicated in post-transplant detrimental inflammatory events, is mandatory to improve islet transplantation success. We sought to characterize the expression of the pro-inflammatory and pro-oxidant mediators during islet culture with a focus on Heme oxygenase (HO-1) and Toll-like receptors-4 signaling pathways. Rat pancreatic islets were isolated and pro-inflammatory and pro-oxidant status were evaluated after 0, 12, 24 and 48 hours of culture through TLR-4, HO-1 and cyclooxygenase-2 (COX-2) expression, CCL-2 and IL-6 secretion, ROS (Reactive Oxygen Species) production (Dihydroethidine staining, DHE) and macrophages migration. To identify the therapeutic target, TLR4 inhibition (CLI-095) and HO-1 activation (cobalt protoporphyrin,CoPP) was performed. Activation of NFκB signaling pathway was also investigated. After isolation and during culture, pancreatic islet exhibited a proinflammatory and prooxidant status (increase levels of TLR-4, COX-2, CCL-2, IL-6, and ROS). Activation of HO-1 or inhibition of TLR-4 decreased inflammatory status and oxidative stress of islets. Moreover, the overexpression of HO-1 induced NFκB phosphorylation while the inhibition of TLR-4 had no effect NFκB activation. Finally, inhibition of pro-inflammatory pathway induced a reduction of macrophages migration. These data demonstrated that the TLR-4 signaling pathway is implicated in early inflammatory events leading to a pro-inflammatory and pro-oxidant status of islets in vitro. Moreover, these results provide the mechanism whereby the benefits of HO-1 target in TLR-4 signaling pathway. HO-1 could be then an interesting target to protect islets before transplantation.
authors.affiliation: DIATHEC, EA 7294, Centre Européen d'Etude du Diabète, Université de Strasbourg, Fédération de Médecine Translationnelle, Strasbourg, France.
authors.forename: Kevin
authors.initials: K
authors.lastname: Vivot
authors.affiliation: DIATHEC, EA 7294, Centre Européen d'Etude du Diabète, Université de Strasbourg, Fédération de Médecine Translationnelle, Strasbourg, France.
authors.forename: Allan
authors.initials: A
authors.lastname: Langlois
authors.affiliation: DIATHEC, EA 7294, Centre Européen d'Etude du Diabète, Université de Strasbourg, Fédération de Médecine Translationnelle, Strasbourg, France.
authors.forename: William
authors.initials: W
authors.lastname: Bietiger
authors.affiliation: DIATHEC, EA 7294, Centre Européen d'Etude du Diabète, Université de Strasbourg, Fédération de Médecine Translationnelle, Strasbourg, France.
authors.forename: Stéphanie
authors.initials: S
authors.lastname: Dal
authors.affiliation: DIATHEC, EA 7294, Centre Européen d'Etude du Diabète, Université de Strasbourg, Fédération de Médecine Translationnelle, Strasbourg, France.
authors.forename: Elodie
authors.initials: E
authors.lastname: Seyfritz
authors.affiliation: DIATHEC, EA 7294, Centre Européen d'Etude du Diabète, Université de Strasbourg, Fédération de Médecine Translationnelle, Strasbourg, France; Structure d'Endocrinologie, Diabète -Nutrition et Addictologie, Pôle NUDE, Hôpitaux Universitaires de Strasbourg, (HUS), Strasbourg, France.
authors.forename: Michel
authors.initials: M
authors.lastname: Pinget
authors.affiliation: DIATHEC, EA 7294, Centre Européen d'Etude du Diabète, Université de Strasbourg, Fédération de Médecine Translationnelle, Strasbourg, France; Structure d'Endocrinologie, Diabète -Nutrition et Addictologie, Pôle NUDE, Hôpitaux Universitaires de Strasbourg, (HUS), Strasbourg, France.
authors.forename: Nathalie
authors.initials: N
authors.lastname: Jeandidier
authors.affiliation: DIATHEC, EA 7294, Centre Européen d'Etude du Diabète, Université de Strasbourg, Fédération de Médecine Translationnelle, Strasbourg, France.
authors.forename: Elisa
authors.initials: E
authors.lastname: Maillard
authors.affiliation: UMR 7034 CNRS, Faculté de Pharmacie, Université de Strasbourg, Illkirch, France.
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Gies
authors.affiliation: DIATHEC, EA 7294, Centre Européen d'Etude du Diabète, Université de Strasbourg, Fédération de Médecine Translationnelle, Strasbourg, France.
authors.forename: Séverine
authors.initials: S
authors.lastname: Sigrist
mesh_terms: D000818:Animals; D051546:Cyclooxygenase 2 / Q000096:biosynthesis; D051547:Heme Oxygenase-1 / Q000096:biosynthesis*; D006801:Humans; D007249:Inflammation / Q000235:genetics* / Q000473:pathology; D015850:Interleukin-6 / Q000096:biosynthesis; D007515:Islets of Langerhans / Q000378:metabolism* / Q000473:pathology; D016381:Islets of Langerhans Transplantation; D008264:Macrophages / Q000378:metabolism / Q000473:pathology; D051381:Rats; D017382:Reactive Oxygen Species / Q000378:metabolism; D015398:Signal Transduction / Q000235:genetics; D051193:Toll-Like Receptors / Q000096:biosynthesis*
chemical_list: D015850:Interleukin-6; D017382:Reactive Oxygen Species; D051193:Toll-Like Receptors; D051547:Heme Oxygenase-1; D051546:Cyclooxygenase 2