title: Associations between hepatic miRNA expression, liver triacylglycerols and gut microbiota during metabolic adaptation to high-fat diet in mice.
abstract: Despite the current pandemic of metabolic diseases, our understanding of the diverse nature of the development of metabolic alterations in people who eat a high-fat diet (HFD) is still poor. We recently demonstrated a cardio-metabolic adaptation in mice fed an HFD, which was characterised by a specific gut and periodontal microbiota profile. Since the severity of hepatic disease is characterised by specific microRNA (miRNA) signatures and the gut microbiota is a key driver of both hepatic disease and miRNA expression, we analysed the expression of three hepatic miRNA and studied their correlation with hepatic triacylglycerol content and gut microbiota.
  
  
  
  Two cohorts of C57BL/6 4-week-old wild-type (WT) male mice (n = 62 and n = 96) were fed an HFD for 3 months to provide a model of metabolic adaptation. Additionally 8-week-old C57BL/6 mice, either WT or of different genotypes, with diverse gut microbiota (ob/ob, Nod1, Cd14 knockout [Cd14KO] and Nod2) or without gut microbiota (axenic mice) were fed a normal chow diet. Following which, glycaemic index, body weight, blood glucose levels and hepatic triacylglycerol levels were measured. Gut (caecum) microbiota taxa were analysed by pyrosequencing. To analyse hepatic miRNA expression, real-time PCR was performed on total extracted miRNA samples. Data were analysed using two-way ANOVA followed by the Dunnett's post hoc test, or by the unpaired Student's t test. A cluster analysis and multivariate analyses were also performed.
  
  
  
  Our results demonstrated that the expression of miR-181a, miR-666 and miR-21 in primary murine hepatocytes is controlled by lipopolysaccharide in a dose-dependent manner. Of the gut microbiota, Firmicutes were positively correlated and Proteobacteria and Bacteroides acidifaciens were negatively correlated with liver triacylglycerol levels. Furthermore, the relative abundance of Firmicutes was negatively correlated with hepatic expression of miR-666 and miR-21. In contrast, the relative abundance of B. acidifaciens was positively correlated with miR-21.
  
  
  
  We propose the involvement of hepatic miRNA, liver triacylglycerols and gut microbiota as a new triad that underlies the molecular mechanisms by which gut microbiota governs hepatic pathophysiology during metabolic adaptation to HFD.
authors.affiliation: Institut National de la Santé et de la Recherche Médicale (Inserm), Toulouse, France.|Unité Mixte de Recherche, Institut de Maladies Métaboliques et Cardiovasculaires (I2MC), Université Paul Sabatier (UPS), Toulouse, France.|Faculté de Chirurgie Dentaire de Toulouse, Université Paul Sabatier, Toulouse, France.
authors.forename: Vincent
authors.initials: V
authors.lastname: Blasco-Baque
authors.affiliation: Vaiomer SAS, Labège, France.
authors.forename: Berengère
authors.initials: B
authors.lastname: Coupé
authors.affiliation: Institut National de la Santé et de la Recherche Médicale (Inserm), Toulouse, France.|Unité Mixte de Recherche, Institut de Maladies Métaboliques et Cardiovasculaires (I2MC), Université Paul Sabatier (UPS), Toulouse, France.
authors.forename: Aurelie
authors.initials: A
authors.lastname: Fabre
authors.affiliation: Institut National de la Santé et de la Recherche Médicale (Inserm), Toulouse, France.|Unité Mixte de Recherche, Institut de Maladies Métaboliques et Cardiovasculaires (I2MC), Université Paul Sabatier (UPS), Toulouse, France.
authors.forename: Sandra
authors.initials: S
authors.lastname: Handgraaf
authors.affiliation: Institut National de la Santé et de la Recherche Médicale (Inserm), Toulouse, France.|Unité Mixte de Recherche, Institut de Maladies Métaboliques et Cardiovasculaires (I2MC), Université Paul Sabatier (UPS), Toulouse, France.
authors.forename: Pierre
authors.initials: P
authors.lastname: Gourdy
authors.affiliation: Institut National de la Santé et de la Recherche Médicale (Inserm), Toulouse, France.|Unité Mixte de Recherche, Institut de Maladies Métaboliques et Cardiovasculaires (I2MC), Université Paul Sabatier (UPS), Toulouse, France.
authors.forename: Jean-François
authors.initials: JF
authors.lastname: Arnal
authors.affiliation: Vaiomer SAS, Labège, France.
authors.forename: Michael
authors.initials: M
authors.lastname: Courtney
authors.affiliation: Pôle d'Innovation Thérapeutique Métabolisme, Recherche de Découvertes, Institut de Recherches Servier, Suresnes, France.
authors.forename: Carole
authors.initials: C
authors.lastname: Schuster-Klein
authors.affiliation: Pôle d'Innovation Thérapeutique Métabolisme, Recherche de Découvertes, Institut de Recherches Servier, Suresnes, France.
authors.forename: Beatrice
authors.initials: B
authors.lastname: Guardiola
authors.affiliation: Institut National de la Santé et de la Recherche Médicale (Inserm), Toulouse, France.|Unité Mixte de Recherche, Institut de Maladies Métaboliques et Cardiovasculaires (I2MC), Université Paul Sabatier (UPS), Toulouse, France.
authors.forename: François
authors.initials: F
authors.lastname: Tercé
authors.affiliation: Institut National de la Santé et de la Recherche Médicale (Inserm), Toulouse, France.|Unité Mixte de Recherche, Institut de Maladies Métaboliques et Cardiovasculaires (I2MC), Université Paul Sabatier (UPS), Toulouse, France.
authors.forename: Rémy
authors.initials: R
authors.lastname: Burcelin
authors.affiliation: Institut National de la Santé et de la Recherche Médicale (Inserm), Toulouse, France. matteo.serino@inserm.fr.|Unité Mixte de Recherche, Institut de Maladies Métaboliques et Cardiovasculaires (I2MC), Université Paul Sabatier (UPS), Toulouse, France. matteo.serino@inserm.fr.|Unité Mixte de Recherche (UMR) 1220, Institut de Recherche en Santé Digestive (IRSD), Université Paul Sabatier (UPS), Centre Hospitalier Universitaire (CHU) Purpan, Place du Docteur Baylac, CS 60039, 31024, Toulouse, Cedex 3, France. matteo.serino@inserm.fr.
authors.forename: Matteo
authors.initials: M
authors.lastname: Serino
mesh_terms: D000818:Animals; D059305:Diet, High-Fat / Q000009:adverse effects; D000069196:Gastrointestinal Microbiome / Q000235:genetics / Q000502:physiology; D005838:Genotype; D022781:Hepatocytes / Q000378:metabolism; D018950:Lipopolysaccharide Receptors / Q000235:genetics / Q000378:metabolism; D008070:Lipopolysaccharides / Q000494:pharmacology; D008099:Liver / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D035683:MicroRNAs / Q000235:genetics / Q000378:metabolism*; D053474:Nod1 Signaling Adaptor Protein / Q000235:genetics / Q000378:metabolism; D053473:Nod2 Signaling Adaptor Protein / Q000235:genetics / Q000378:metabolism; D016133:Polymerase Chain Reaction; D014280:Triglycerides / Q000378:metabolism*
chemical_list: D018950:Lipopolysaccharide Receptors; D008070:Lipopolysaccharides; D035683:MicroRNAs; D053474:Nod1 Signaling Adaptor Protein; C507873:Nod1 protein, mouse; D053473:Nod2 Signaling Adaptor Protein; C495945:Nod2 protein, mouse; D014280:Triglycerides
keywords: Gut microbiota; High-fat diet; Liver triacylglycerol content; Metabolic adaptation; Metabolic diseases; miRNA