characterization of gut microbiota profiles in nod2-/- and nod2+/+ mice and effect of genotype and environment on severity of colitis. Environmental factors affect the gut microbiota composition of Nod2 deficient mice and contribute to severity of colitis

In order to evaluate the effect of Nod2 genotype and environmental factors, such as gut microbiota composition in the previously observed response to experimental induced-colitis, we performed meta-taxonomic analysis of gut microbiota in Nod2-/- and Nod2+/+ mice from faeces collected at different time points: (i) at 4 weeks of age (at weaning, before the housing conditions were established); (ii) 8 weeks of age (before TNBS-colitis induction), and (iii) at day 3 after TNBS colitis induction. We compared the gut microbial profiles in both cohousing and no-cohousing conditions and after colitis induction by TNBS, through the pyrosequencing of the V3-V5 hypervariable region of 16S rRNA gene. The taxonomic distribution in the Nod2-/- and Nod2+/+ mice showed variations in gut microbiota composition in the different experimental time points. Microbial profiles correlated with cytokines production and CD4+LAP+ cells induction and severity of colitis.