Fig. 3

Putative mechanisms involved in microbiota-mediated ASNP contribution to IBD. Once reached intestinal mucosa, biologically modified ASNP may persist into the mucus layer interacting with the gut microbiota. ASNP-microbial interaction may shift microbial diversity through possible different mechanisms (see text), such as nutritional advantages for selected bacteria due to the delivery of adsorbed metabolites. The resulting dysbiosis is associated with a reduction of mucus secretion, increased amounts of selective LPS variants, alteration of epithelial barrier function, and penetration of inflammatory agents (such as LPS-doped-ASNP). Mucosal innate immune cells (dendritic cells, neutrophils and macrophages) engulf components of the altered microbiota with activation of the inflammatory response and the consequent recruitment of selected T-lymphocyte subsets