Early Gut Microbiota Intervention Suppresses DSS-Induced Inflammatory Responses by Deactivating TLR/NLR Signalling in Pigs

Recent metagenomic studies suggest that innate and adaptive immune phenotypes can be programmed via gut microbiota-host interactions mediated via activation of pattern recognition receptors (PRRs) on host cells. In this study, we used two extremely different pig lines (the Yorkshire and the Tibetan) to test the hypothesis that the transplantation of gut microbiota could transfer certain immunologic characteristics from donor to recipient. The faecal microbiota of these two pig lines was transplanted in healthy commercial hybrid newborn piglets to establish the “Tibetan-intervened” and “Yorkshire-intervened” porcine models. Then, acute colitis was induced using dextran sulphate sodium (DSS), which activated Toll-/NOD-like receptor (TLR/NLR) signalling in the colonic tissues of the “Yorkshire-intervened” piglets, leading to increases in pro-inflammatory cytokines and immune cells and causing intestinal injuries. Conversely, DSS administration had little influence on the “Tibetan-intervened” piglets, which showed no significant inflammation and no changes in cytokines, immune cells, or signalling molecules, including TLRs, NLRs, MYD88 and NF-κB, after DSS treatment. These results indicate that pigs inoculated with the Tibetan microbiota acquired relatively strong resistance to experimental colitis, suggesting that the genotype of the host contributes to the uniqueness of its intestinal microbial community, whereas the microbiota plays a vital role in programming the immune phenotypes of the host.