title: The nod-like receptor, Nlrp12, plays an anti-inflammatory role in experimental autoimmune encephalomyelitis.
abstract: BACKGROUND
  Multiple sclerosis (MS) is an organ-specific autoimmune disease resulting in demyelinating plaques throughout the central nervous system. In MS, the exact role of microglia remains unknown. On one hand, they can present antigens, skew T cell responses, and upregulate the expression of pro-inflammatory molecules. On the other hand, microglia may express anti-inflammatory molecules and inhibit inflammation. Microglia express a wide variety of immune receptors such as nod-like receptors (NLRs). NLRs are intracellular receptors capable of regulating both innate and adaptive immune responses. Among NLRs, Nlrp12 is largely expressed in cells of myeloid origins. It plays a role in immune inflammatory responses by negatively regulating the nuclear factor-kappa B (NF-κB) pathway. Thus, we hypothesize that Nlrp12 suppresses inflammation and ameliorates the course of MS.
  
  
  METHODS
  We used experimental autoimmune encephalomyelitis (EAE), a well-characterized mouse model of MS. EAE was induced in wild-type (WT) and Nlrp12 (-/-) mice with myelin oligodendrocyte glycoprotein (MOG):complete Freud's adjuvant (CFA). The spinal cords of healthy and immunized mice were extracted for immunofluorescence and pro-inflammatory gene analysis. Primary murine cortical microglia cell cultures of WT and Nlrp12 (-/-) were prepared with cortices of 1-day-old pups. The cells were stimulated with lipopolysaccharide (LPS) and analyzed for the expression of pro-inflammatory genes as well as pro-inflammatory molecule secretions.
  
  
  RESULTS
  Over the course of 9 weeks, the Nlrp12 (-/-) mice demonstrated increased severity in the disease state, where they developed the disease earlier and reached significantly higher clinical scores compared to the WT mice. The spinal cords of immunized WT mice relative to healthy WT mice revealed a significant increase in Nlrp12 messenger ribonucleic acid (mRNA) expression at 1, 3, and 5 weeks post injection. A significant increase in the expression of pro-inflammatory genes Ccr5, Cox2, and IL-1β was found in the spinal cords of the Nlrp12 (-/-) mice relative to the WT mice (P < 0.05). A significant increase in the level of gliosis was observed in the spinal cords of the Nlrp12 (-/-) mice compared to the WT mice after 9 weeks of disease (P < 0.05). Primary Nlrp12 (-/-) microglia cells demonstrated a significant increase in inducible nitric oxide synthase (iNOS) expression (P < 0.05) and secreted significantly (P < 0.05) more tumor necrosis factor alpha (TNFα), interleukin-6 (IL-6), and nitric oxide (NO).
  
  
  CONCLUSIONS
  Nlrp12 plays a protective role by suppressing inflammation during the development of EAE. The absence of Nlrp12 results in an increased inflammatory response.
authors.affiliation: Program of Immunology, Department of Pediatrics, CR-CHUS, Faculty of Medicine and Health Sciences, University of Sherbrooke, Sherbrooke, Quebec, Canada. Marjan.Gharagozloo@usherbrooke.ca.
authors.forename: Marjan
authors.initials: M
authors.lastname: Gharagozloo
authors.affiliation: Program of Immunology, Department of Pediatrics, CR-CHUS, Faculty of Medicine and Health Sciences, University of Sherbrooke, Sherbrooke, Quebec, Canada. Tara.Mahvelati@usherbrooke.ca.
authors.forename: Tara M
authors.initials: TM
authors.lastname: Mahvelati
authors.affiliation: Program of Immunology, Department of Pediatrics, CR-CHUS, Faculty of Medicine and Health Sciences, University of Sherbrooke, Sherbrooke, Quebec, Canada. Emilie.Imbeault@usherbrooke.ca.
authors.forename: Emilie
authors.initials: E
authors.lastname: Imbeault
authors.affiliation: Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada. pavel.gris@mcgill.ca.
authors.forename: Pavel
authors.initials: P
authors.lastname: Gris
authors.affiliation: Program of Immunology, Department of Pediatrics, CR-CHUS, Faculty of Medicine and Health Sciences, University of Sherbrooke, Sherbrooke, Quebec, Canada. Echarki.Zerif@USherbrooke.ca.
authors.forename: Echarki
authors.initials: E
authors.lastname: Zerif
authors.affiliation: Program of Immunology, Department of Pediatrics, CR-CHUS, Faculty of Medicine and Health Sciences, University of Sherbrooke, Sherbrooke, Quebec, Canada. Diwakar.Bobbala@USherbrooke.ca.
authors.forename: Diwakar
authors.initials: D
authors.lastname: Bobbala
authors.affiliation: Program of Immunology, Department of Pediatrics, CR-CHUS, Faculty of Medicine and Health Sciences, University of Sherbrooke, Sherbrooke, Quebec, Canada. Subburaj.Ilangumaran@USherbrooke.ca.
authors.forename: Subburaj
authors.initials: S
authors.lastname: Ilangumaran
authors.affiliation: Program of Immunology, Department of Pediatrics, CR-CHUS, Faculty of Medicine and Health Sciences, University of Sherbrooke, Sherbrooke, Quebec, Canada. abdelaziz.amrani@usherbrooke.ca.
authors.forename: Abdelaziz
authors.initials: A
authors.lastname: Amrani
authors.affiliation: Program of Immunology, Department of Pediatrics, CR-CHUS, Faculty of Medicine and Health Sciences, University of Sherbrooke, Sherbrooke, Quebec, Canada. Denis.Gris@usherbrooke.ca.
authors.forename: Denis
authors.initials: D
authors.lastname: Gris
mesh_terms: D000818:Animals; D016207:Cytokines / Q000096:biosynthesis / Q000378:metabolism; D004681:Encephalomyelitis, Autoimmune, Experimental / Q000473:pathology*; D005260:Female; D005911:Gliosis / Q000235:genetics / Q000473:pathology; D007249:Inflammation / Q000235:genetics / Q000473:pathology*; D015847:Interleukin-4 / Q000378:metabolism; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics*; D008070:Lipopolysaccharides / Q000494:pharmacology; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D017628:Microglia / Q000378:metabolism; D009103:Multiple Sclerosis / Q000473:pathology; D052247:Nitric Oxide Synthase Type II / Q000096:biosynthesis; D063345:Oligodendrocyte-Myelin Glycoprotein / Q000378:metabolism; D013116:Spinal Cord / Q000276:immunology / Q000473:pathology; D013601:T-Lymphocytes
chemical_list: D016207:Cytokines; D047908:Intracellular Signaling Peptides and Proteins; D008070:Lipopolysaccharides; C553199:NLRP12 protein, mouse; D063345:Oligodendrocyte-Myelin Glycoprotein; D015847:Interleukin-4; D052247:Nitric Oxide Synthase Type II