Microbial products from probiotic bacteria inhibit Salmonella enteritidis 857-induced IL-8 synthesis in Caco-2 cells

Abstract

Oral administration of Lactobacillus spp. as probiotics is gaining importance in the treatment of intestinal inflammations. However, their mechanism of action is unknown. We investigated whether nonspecific binding Lactobacillus casei Shirota (LcS) and mannose-specific Lactobacillus plantarum 299v (Lp) and their spent culture supernatant (SCS) affect Salmonella enteritidis 857 (Se) growth, IL-8 and Hsp70 syntheses. In one set of experiments human enterocyte-like Caco-2 cells were infected with LcS, Lp or Se at 1-500 bacteria per cell for 1 h. In another set, cells were exposed to Se (0-200 per cell, 1 h) after exposure to lactobacilli (LB) (500 per cell, 30 min) or by co-incubation of Se and LB (1 h). The third set of experiments involved exposure of cells for 1 h to SCS or Se (100 per cell) pretreated (1 h) in SCS. The effect of LB SCS on Se growth was evaluated by agar plate diffusion test. IL-8 and Hsp70 were assessed over 2-24 h using ELISA and Western blotting, respectively. Neither LcS nor Lp affected the Se growth and IL-8 production. In addition, they did not induce Hsp70 expression by Caco-2 cells. Instead, their SCS inhibited the Se growth and IL-8 production and induced the expression of Hsp70 by both crypt- and villus-like cells. The beneficial effect of Lactobacillus spp. to the intestinal inflammations might be associated with a decrease in IL-8 levels. This effect could be mediated, at least in part, via a secreted antimicrobial product(s) either directly against the pathogens or indirectly through the synthesis of Hsp70.

Lactobacilli Reduce Chemokine IL-8 Production in Response to TNF-αandSalmonellaChallenge of Caco-2 Cells

“…Our results show that the lactobacilli supernatant inhibited TNF- α -induced IL-8 production (Figure 4). This finding is similar to those of other studies, which showed that Lactobacillus strains, including L. rhamnosus , Lactobacillus helveticus , Lactobacillus casei , and L. plantarum , upregulate anti-inflammatory mediator (IL-10) and downregulate proinflammatory mediators (IL-8 and TNF- α ) [35–37]. These results imply that the soluble substances secreted by lactobacilli also inhibit TNF- α -induced IL-8 production.…”

Metabolites of Lactobacillus plantarum 2142 Prevent Oxidative Stress-Induced Overexpression of Proinflammatory Cytokines in IPEC-J2 Cell Line

“…It was also ascertained that chemical interaction between H 2 O 2 and SCS can not be responsible for this beneficial probiotic effect. In accordance with our findings, it was also reported that lactobacilli SCS inhibited IL-8 production and induced the expression of Hsp70 in Caco-2 crypt-and villus-like cells in enteropathogen Salmonella enteritidis 857 infection [31]. The mode of action behind the downregulation of elevated proinflammatory cytokine synthe- It was found that levan is one of the potential immunstimulant components released into the supernatant by B. amyloliquefaciens CECT 5940 equipped with levansucrase enzyme [53].…”

“…There is some evidence that administration of Lactobacillus spp. supernatant can induce the synthesis of Hsp70 in both crypt-and villus-like Caco-2 cells suggesting one putative mechanism behind the beneficial properties of the non-starter lactobacilli in host defence against infection and inflammation [31,32].…”

Gut microbiota imbalance and chaperoning system malfunction are central to ulcerative colitis pathogenesis and can be counteracted with specifically designed probiotics: a working hypothesis

“…Beneficial systemic effects of probiotics beyond the bowel in UC Probiotics, as well as commensal bacteria of a normal bowel, can induce cytoprotective HSP expression by secretion of polypeptides or other molecules that interact with epithelial cells [100,101]. In this way, HSPs participate in the normal anti-stress response of a healthy bowel.…”