title: Persistent Organic Pollutants Modify Gut Microbiota-Host Metabolic Homeostasis in Mice Through Aryl Hydrocarbon Receptor Activation.
abstract: BACKGROUND
  Alteration of the gut microbiota through diet and environmental contaminants may disturb physiological homeostasis, leading to various diseases including obesity and type 2 diabetes. Because most exposure to environmentally persistent organic pollutants (POPs) occurs through the diet, the host gastrointestinal tract and commensal gut microbiota are likely to be exposed to POPs.
  
  
  OBJECTIVE
  We examined the effect of 2,3,7,8-tetrachlorodibenzofuran (TCDF), a persistent environmental contaminant, on gut microbiota and host metabolism, and we examined correlations between gut microbiota composition and signaling pathways.
  
  
  METHODS
  Six-week-old male wild-type and Ahr-/- mice on the C57BL/6J background were treated with 24 μg/kg TCDF in the diet for 5 days. We used 16S rRNA gene sequencing, 1H nuclear magnetic resonance (NMR) metabolomics, targeted ultra-performance liquid chromatography coupled with triplequadrupole mass spectrometry, and biochemical assays to determine the microbiota compositions and the physiological and metabolic effects of TCDF.
  
  
  RESULTS
  Dietary TCDF altered the gut microbiota by shifting the ratio of Firmicutes to Bacteroidetes. TCDF-treated mouse cecal contents were enriched with Butyrivibrio spp. but depleted in Oscillobacter spp. compared with vehicle-treated mice. These changes in the gut microbiota were associated with altered bile acid metabolism. Further, dietary TCDF inhibited the farnesoid X receptor (FXR) signaling pathway, triggered significant inflammation and host metabolic disorders as a result of activation of bacterial fermentation, and altered hepatic lipogenesis, gluconeogenesis, and glycogenolysis in an AHR-dependent manner.
  
  
  CONCLUSIONS
  These findings provide new insights into the biochemical consequences of TCDF exposure involving the alteration of the gut microbiota, modulation of nuclear receptor signaling, and disruption of host metabolism.
authors.affiliation: Center for Molecular Toxicology and Carcinogenesis, Department of Veterinary and Biomedical Sciences, The Pennsylvania State University, University Park, Pennsylvania, USA.
authors.forename: Limin
authors.initials: L
authors.lastname: Zhang
authors.forename: Robert G
authors.initials: RG
authors.lastname: Nichols
authors.forename: Jared
authors.initials: J
authors.lastname: Correll
authors.forename: Iain A
authors.initials: IA
authors.lastname: Murray
authors.forename: Naoki
authors.initials: N
authors.lastname: Tanaka
authors.forename: Philip B
authors.initials: PB
authors.lastname: Smith
authors.forename: Troy D
authors.initials: TD
authors.lastname: Hubbard
authors.forename: Aswathy
authors.initials: A
authors.lastname: Sebastian
authors.forename: Istvan
authors.initials: I
authors.lastname: Albert
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Hatzakis
authors.forename: Frank J
authors.initials: FJ
authors.lastname: Gonzalez
authors.forename: Gary H
authors.initials: GH
authors.lastname: Perdew
authors.forename: Andrew D
authors.initials: AD
authors.lastname: Patterson
mesh_terms: D000818:Animals; D001572:Benzofurans / Q000633:toxicity*; D001647:Bile Acids and Salts / Q000378:metabolism; D004032:Diet; D004785:Environmental Pollutants / Q000633:toxicity*; D000069196:Gastrointestinal Microbiome / Q000187:drug effects* / Q000235:genetics; D041981:Gastrointestinal Tract / Q000382:microbiology*; D006706:Homeostasis; D008099:Liver / Q000187:drug effects* / Q000378:metabolism; D008297:Male; D055432:Metabolomics; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D064307:Microbiota / Q000187:drug effects* / Q000235:genetics; D012336:RNA, Ribosomal, 16S / Q000378:metabolism; D018336:Receptors, Aryl Hydrocarbon / Q000235:genetics / Q000378:metabolism*; D018160:Receptors, Cytoplasmic and Nuclear / Q000378:metabolism; D015398:Signal Transduction; D000099150:Receptor, Farnesoid X-Activated
chemical_list: D001572:Benzofurans; D001647:Bile Acids and Salts; D004785:Environmental Pollutants; D012336:RNA, Ribosomal, 16S; D018336:Receptors, Aryl Hydrocarbon; D018160:Receptors, Cytoplasmic and Nuclear; D000099150:Receptor, Farnesoid X-Activated; C014211:2,3,7,8-tetrachlorodibenzofuran