Exopolysaccharide production by <i>Lactobacillus plantarum</i> T10 is responsible for the probiotic activity in enhancing intestinal barrier function <i>in vitro</i> and <i>in vivo</i>

Abstract

<i>Lactobacillus</i> probiotics exert their effects in a strain-specific and metabolite-specific manner. This study aims to identify lactobacilli that can effectively enhance the intestinal barrier function both <i>in vitro</i> and <i>in vivo</i> and to investigate the underlying metabolite and molecular mechanisms involved. Nine <i>Lactobacillus</i> isolates were evaluated for their ability to enhance the IPEC-J2 cellular barrier function and for their anti-inflammatory and anti-apoptotic effects in IPEC-J2 cells after an enterotoxigenic <i>Escherichia coli</i> challenge. Of the nine isolates, <i>L. plantarum</i> T10 demonstrated significant advantages in enhancing the cellular barrier function and displayed anti-inflammatory and anti-apoptotic activities <i>in vitro</i>. The bioactivities of <i>L. plantarum</i> T10 were primarily attributed to the production of exopolysaccharides, which exerted their effects through the TLR-mediated p38 MAPK pathway in ETEC-challenged IPEC-J2 cells. Furthermore, the production of EPS by <i>L. plantarum</i> T10 led to the alleviation of dextran sulfate sodium-induced colitis by reducing intestinal damage and enhancing the intestinal barrier function in mice. The EPS is classified as a heteropolysaccharide with an average molecular weight of 23.0 kDa. It is primarily composed of mannose, glucose, and ribose. These findings have practical implications for the targeted screening of lactobacilli used in the production of probiotics and postbiotics with strain-specific features of exopolysaccharides.