Gut microbiota in experimental murine model of Graves’ orbitopathy established in different environments may modulate clinical presentation of disease
Creators: name: Masetti, Giulia
name: Sajad Moshkelgosha
name: Hedda-Luise Köhling
name: Covelli, Danila
name: Banga, Jasvinder Paul
name: Berchner-Pfannschmidt, Utta
name: Horstmann, Mareike
name: Diaz-Cano, Salvador J.
name: Gina-Eva Goertz
name: Plummer, Sue
name: Eckstein, Anja
name: Ludgate, Marian
name: Biscarini, Filippo
name: Marchesi, Julian
name: INDIGO Consortium
Publisher: name: figshare
Year: 2018
Subjects: subject: 110703 Autoimmunity
subject: FOS: Clinical medicine
subject: FOS: Clinical medicine
subject: 110303 Clinical Microbiology
subject: 110306 Endocrinology
subject: 110799 Immunology not elsewhere classified
subject: 110706 Immunogenetics (incl. Genetic Immunology)
subject: 110705 Humoural Immunology and Immunochemistry
subject: 110707 Innate Immunity
subject: 110801 Medical Bacteriology
subject: FOS: Health sciences
subject: FOS: Health sciences
subject: 110316 Pathology (excl. Oral Pathology)
subject: Pathogenesis

description: Background: Variation in induced models of autoimmunity has been attributed to the housing environment and its effect on the gut microbiota. In Graves' disease (GD), autoantibodies to the thyrotropin receptor (TSHR) cause autoimmune hyperthyroidism. Many GD patients develop Graves' orbitopathy (GO) characterized by orbital tissue remodeling including adipogenesis. Murine models of GD/GO would help delineate pathogenetic mechanisms and although several have been reported most lack reproducibility. A model comprising immunization of female BALBc mice with a TSHR expression plasmid using in vivo electroporation, was reproduced in two independent laboratories. Similar orbital disease was induced in both centers, but differences were apparent (e.g., hyperthyroidism in Center 1 but not Center 2). We hypothesized a role for the gut microbiota influencing the outcome and reproducibility of induced GO. Results: We combined metataxonomics (16S rRNA gene sequencing) and traditional microbial culture of the intestinal contents from the GO murine model, to analyze the gut microbiota in the two centers. We observed significant differences in alpha, beta-diversity and in the taxonomic profiles, e.g. Operational Taxonomic Units (OTUs) from the genus Lactobacillus were more abundant in Center 2, Bacteroides and Bifidobacterium counts were more abundant in Center 1 where we also observed a negative correlation between the OTUs of the genus Intestinimonas and TSHR autoantibodies. Traditional microbiology largely confirmed the metataxonomics data and indicated significantly higher yeast counts in Center 1 TSHR-immunized mice. We also compared the gut microbiota between immunization groups within the Center 2, comprising the TSHR or βgal control immunized mice and naïve untreated mice. We observed a shift of the TSHR immunized mice bacterial communities described by the beta-diversity weighted Unifrac. Furthermore, we observed a significant positive correlation between the presence of Firmicutes and orbital-adipogenesis specifically in TSHR-immunized mice. Conclusions: The significant differences observed in microbiota composition from BALBc mice undergoing the same immunization protocol in comparable specific-pathogen free (SPF) units in different centers support a role for the gut microbiota in modulating the induced response. The gut microbiota might also contribute to the heterogeneity of induced response since we report potential disease-associated microbial taxonomies and correlation with ocular disease.