Weissella cibaria Attenuated LPS-Induced Dysfunction of Intestinal Epithelial Barrier in a Caco-2 Cell Monolayer Model

Abstract

The dysfunction of the intestinal epithelial barrier contributes to local or systemic infection and inflammation. Some lactic acid bacteria (LAB) strains had been shown to improve the conditions of barrier function and, for this reason, are recognized as probiotics. <i>Weissella cibaria</i>, a species belonging to the LAB group, is known to promote several health benefits. However, the role of <i>W. cibaria</i> in regulating the integrity of the intestinal epithelial barrier has not yet been investigated. In this study, <i>W. cibaria</i> MW01 was isolated from Chinese sauerkraut and was selected based on its functional features, such as gastric juice and bile salt tolerance, besides antagonistic activity against pathogenic bacteria. In a cellular model of the intestinal barrier, it was observed that <i>W. cibaria</i> was able to adhere more efficiently than <i>Lactobacillus rhamnosus</i> GG in Caco-2 cells. Moreover, the LPS-induced inflammation in Caco-2 cells was attenuated by the treatment with <i>W. cibaria</i> MW01, which reduced the synthesis of TNF-α, IL-6, and IL-8. In addition, it was noted that the treatment with <i>W. cibaria</i> MW01 recovered the integrity of the Caco-2 cell monolayer exposed to LPS. Furthermore, <i>W. cibaria</i> MW01 significantly alleviated LPS-induced downregulation of tight junction proteins (TJP) (claudin, occludin, and tight junction protein-1). Mechanistically, <i>W. cibaria</i> MW01 inhibited the translocation of NF-κB to the nucleus and deactivated the MLCK-pMLC pathway during LPS exposure. Thus, <i>W. cibaria</i> MW01, as a potential probiotic, can protect intestinal epithelial barrier function by regulating inflammation and expression of TJP via the NF-κB-mediated MLCK-pMLC pathway.