Symbioses between humans and the microbiome influence broad aspects of human biology including nutrition, immune function, and brain development. Altered microbial community profiles are associated with a variety of chronic diseases such as inflammatory bowel disease, allergic conditions, obesity, and psychiatric and neurological disorders. This transversal axis aims at interpreting the major biological roles of microbiome in health and disease, in relation to nutrition during lifespan. Example of transversal projects includes:
(i) relationship between microbiome dysbiosis and iron overload diseases illustrated by human patients with hemochromatosis (HFE-/-) and periodontitis. In hemochromatosis mice models (Hfe-/-) microbiota was shown to be altered. Whether such differences are related to differential iron status between normal and iron loaded conditions remains to be determined. Rat with aceruloplasminemia will also be studied. In addition, whether subtle modifications of microbiota composition may alter iron absorption and/or systemic iron balance is not known.
(ii) Changes in the salivary and oral microbiota of patients in coma or in long stay in intensive care, with the goal of identyfing a predictive marker of patient’s survival.
(iii) The role of the microbiome in rheumatic diseases, particularly in joint diseases, particularly during iron overload linked to genetic hemochromatosis.
(iv) The relationships between oral microbiome dysbiosis and the occurrence of chronic oral diseases and their relationship with systemic chronic diseases.
(v) Microbiota as a main actor of gut signalling.
A large part of the project of NGB focuses on the impact of food on gut signalling to organs involved in metabolic homeostasis and behaviour, such as the brain, the pancreas and the liver. Microbiota is at the frontline when facing nutritional changes; its subsequent adaptation in terms of composition and metabolism may modulate host biology. The spatio-temporal dynamics of microbiota adaptation to dietary changes (lipid quality and quantity, pre- and probiotic supplementation) will be investigated in close relation with host responses in infant and adult animal models. Microbiota composition (16S sequencing) and/or metabolome will be evaluated in–house or through collaborations in order to identify bacterial groups or metabolites influencing intestinal homeostasis and gut-pancreas, gut-brain and gut-liver axis.