title: Group I metabotropic glutamate receptor mediated dynamic immune dysfunction in children with fragile X syndrome.
abstract: BACKGROUND
  Fragile X syndrome (FXS) is the leading cause of inheritable intellectual disability in male children, and is predominantly caused by a single gene mutation resulting in expanded trinucleotide CGG-repeats within the 5' untranslated region of the fragile X mental retardation (FMR1) gene. Reports have suggested the presence of immune dysregulation in FXS with evidence of altered plasma cytokine levels; however, no studies have directly assessed functional cellular immune responses in children with FXS. In order to ascertain if immune dysregulation is present in children with FXS, dynamic cellular responses to immune stimulation were examined.
  
  
  METHODS
  Peripheral blood mononuclear cells (PBMC) were from male children with FXS (n=27) and from male aged-matched typically developing (TD) controls (n=8). PBMC were cultured for 48 hours in media alone or with lipopolysaccharides (LPS; 1 μg/mL) to stimulate the innate immune response or with phytohemagglutinin (PHA; 8 μg/mL) to stimulate the adaptive T-cell response. Additionally, the group I mGluR agonist, DHPG, was added to cultures to ascertain the role of mGluR signaling in the immune response in subject with FXS. Supernatants were harvested and cytokine levels were assessed using Luminex multiplexing technology.
  
  
  RESULTS
  Children with FXS displayed similar innate immune response following challenge with LPS alone when compared with TD controls; however, when LPS was added in the presence of a group I mGluR agonist, DHPG, increased immune response were observed in children with FXS for a number of pro-inflammatory cytokines including IL-6 (P=0.02), and IL-12p40 (P<0.01). Following PHA stimulation, with or without DHPG, no significant differences between subjects with FXS and TD were seen.
  
  
  CONCLUSIONS
  In unstimulated cultures, subjects with FXS did not display altered dynamic immune response to LPS or PHA alone; however, subjects with FXS showed an altered response to co-current stimulation of LPS and DHPG, such that subjects with FXS failed to inhibit production of pro-inflammatory cytokines, suggesting a role of group I mGluR signaling in innate immune responses in FXS.
authors.forename: Milo
authors.initials: M
authors.lastname: Careaga
authors.forename: Tamanna
authors.initials: T
authors.lastname: Noyon
authors.forename: Kirin
authors.initials: K
authors.lastname: Basuta
authors.forename: Judy
authors.initials: J
authors.lastname: Van de Water
authors.forename: Flora
authors.initials: F
authors.lastname: Tassone
authors.forename: Randi J
authors.initials: RJ
authors.lastname: Hagerman
authors.affiliation: Department of Medical Microbiology and Immunology, and the MIND Institute, UC Davis, 2805, 50th Street, Sacramento, CA 95817, USA. pashwood@ucdavis.edu.
authors.forename: Paul
authors.initials: P
authors.lastname: Ashwood
mesh_terms: D016022:Case-Control Studies; D002478:Cells, Cultured; D002648:Child; D002675:Child, Preschool; D016207:Cytokines / Q000378:metabolism*; D018690:Excitatory Amino Acid Agonists / Q000494:pharmacology; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology; D051860:Fragile X Messenger Ribonucleoprotein 1 / Q000235:genetics; D005600:Fragile X Syndrome / Q000150:complications / Q000235:genetics / Q000473:pathology*; D006801:Humans; D007963:Leukocytes, Mononuclear / Q000187:drug effects / Q000378:metabolism*; D008070:Lipopolysaccharides / Q000494:pharmacology; D008297:Male; D008734:Methoxyhydroxyphenylglycol / Q000031:analogs & derivatives / Q000494:pharmacology; D008934:Mitogens / Q000494:pharmacology; D010835:Phytohemagglutinins / Q000494:pharmacology; D011725:Pyridines / Q000494:pharmacology; D018094:Receptors, Metabotropic Glutamate / Q000378:metabolism*; D018709:Statistics, Nonparametric; D013844:Thiazoles / Q000494:pharmacology; D019680:Trinucleotide Repeat Expansion / Q000235:genetics
chemical_list: D016207:Cytokines; D018690:Excitatory Amino Acid Agonists; D018691:Excitatory Amino Acid Antagonists; D051860:Fragile X Messenger Ribonucleoprotein 1; D008070:Lipopolysaccharides; D008734:Methoxyhydroxyphenylglycol; D008934:Mitogens; D010835:Phytohemagglutinins; D011725:Pyridines; D018094:Receptors, Metabotropic Glutamate; D013844:Thiazoles; C472365:3-((2-methyl-1,3-thiazol-4-yl)ethynyl)pyridine; C104077:metabotropic glutamate receptor type 1; C010117:3,4-dihydroxyphenylglycol