Postbiotics derived from 1.0386 ameliorate lipopolysaccharide-induced tight junction injury MicroRNA-200c-3p mediated activation of the MLCK-MLC pathway in Caco-2 cells.

1.0386 repairs intestinal epithelial tight junction injury, and the present study was designed to further explore the role of its postbiotics, including the surface protein (1.0386-Slp), peptidoglycan (1.0386-PG) and exopolysaccharide (1.0386-EPS). The results showed that they all could improve the lipopolysaccharide (LPS)-induced decrease of transepithelial electrical resistance, increase of paracellular permeability, release of inflammatory factors, and disruption of tight junctions in Caco-2 cells, and the repairing effect of 1.0386-Slp was better than those of 1.0386-PG and 1.0386-EPS, and was similar to that of 1.0386. Moreover, either 1.0386 or 1.0386-Slp intervention significantly increased the expression of miR-200c inhibited by LPS, while the miR-200c inhibitor weakened the ability of 1.0386-Slp to promote the expression of tight junction proteins (ZO-1, occludin and claudin-1). Meanwhile, 1.0386-Slp restored the distribution of tight junction proteins and inhibited the increase of NF-κB p65, MLC and pMLC protein expression evoked by LPS. However, the addition of miR-200c inhibitors or mimics weakened or strengthened the down-regulation of MLCK-MLC pathway protein expression by 1.0386-Slp, respectively. In summary, 1.0386-Slp may be the main efficacy component of 1.0386, and miR-200c may be involved in the process of 1.0386-Slp inhibiting the MLCK pathway to repair intestinal epithelial tight junction injury.