Title : Gut associated Lactobacillus johnsonii enhanced barrier function in colitis model mouse
Abstract:
Intestinal bacteria interact and communicate with the host intestinal epithelium by binding to specific host receptors. However, the host intestinal receptors for bacterial binding and the role in host health are not well understood. In the present study, Lactobacillus johnsonii MG (MG) with interaction with mouse intestinal tract was screened from mouse feces and analyzed its role in the intestinal tract. To identify the intestinal receptors involved in the bacterial binding, surface layer proteins isolated from MG were bound with affinity resin and intestinal proteins with affinity to MG were purified. The purified gut protein was identified as a member of tight junction protein, JAM-2. H2O2 damaged tight junction of Caco-2 cells were improved by the treatment with MG throughout activations of various genes involved in tight junction, inflammation, transcriptional regulator, and apoptosis. Then, tight junction associating MG was challenged on dextran sulfate sodium (DSS)-induced colitis model mouse to confirm the anti-inflammatory effect. After the DSS treatment for 9 days, mice reduced body weight for 4 days, then naturally recovered it. After 3 days of washout period, the following MG treatment showed faster recovery of body weight than that of not-treated mice. MG treated mice also showed improvement of inflammatory damage in gut on DSS treated mice. By the treatment with MG, genes for ZO-1, LAMA3 and ITGA2 in matrix of tight junction and MMP1 in apoptosis were mainly upregulated. Additionally, MG affected on the DSS-induced gut microbiota by regulation of Ruminococcaceae, Bacteroides and Lachnospiraceae. We report here the potential of gut associating L. johnsonii MG on gut barrier function and intestinal microbiota in colitis model mice.
