Inhibition of Salmonella-induced IL-8 synthesis and expression of Hsp70 in enterocyte-like Caco-2 cells after exposure to non-starter lactobacilli

Abstract

Oral administration of lactobacilli as probiotics is gaining importance in the treatment of intestinal inflammations. We investigated the effect of non-starter lactobacilli Lactobacillus casei subsp casei 2756, Lactobacillus curvatus 2775, and Lactobacillus plantarum 2142 as well as their spent culture supernatants (SCS) on Salmonella enteritidis 857 growth, interleukin (IL)-8 and heat shock protein 70 (Hsp70) synthesis in undifferentiated crypt-like and differentiated villus-like Caco-2 cells. The cells were infected with graded numbers of non-starter lactobacilli or S. enteritidis 857 for 1 h and allowed to recover for 24 h or exposed to 200 bacteria/cell for 1 h and allowed to recover for different periods of time. In another experiment S. enteritidis 857 was first pre-treated with SCS-lactobacilli for 1 h before infecting the cells. The levels of IL-8 and Hsp70 were assessed using sandwich ELISA and immunostaining of Western blots, respectively. The effect of SCS-lactobacilli on S. enteritidis 857 growth was evaluated by agar plate diffusion test.The non-starter lactobacilli induced a significant increase in the levels of both IL-8 and Hsp70. However, compared with the S. enteritidis 857 induced IL-8 synthesis, the levels of IL-8 induced by the lactobacilli at any equivalent bacterial number were far lower. After exposure of Caco-2 cells to S. enteritidis 857 pre-treated with SCS-lactobacilli, it appeared that their SCS inhibited the S. enteritidis 857 growth and IL-8 synthesis and in addition induced the expression of Hsp70. The differences in response of crypt-and villus-like Caco-2 cells are merely a reflection of their differentiation status.Our data suggest that the beneficial effect of non-starter lactobacilli to the intestinal inflammations might be associated with a decrease of the IL-8 levels. This effect could be mediated, at least in part, by the bacteria themselves or via a secreted antimicrobial product(s) either directly against the pathogens or indirectly through the synthesis of Hsp70.

Epigenetic modification: possible approach to reduceSalmonella entericaserovar enteritidis susceptibility under stress conditions

“…These mediators are aimed at eliminating the pathogens and protecting the cells, and their down-regulation before resolving the inflammation stress would tend to favour the Salmonella colonization. This down-regulation is mediated, at least in part, by way of Hsp70 synthesis (Yoo et al, 2000;Malago et al, 2005;Nemeth et al, 2006). This evidence reports a significant correlation between Hsp70 expression and S. Enteritidis colonization and supports our findings on the relationship between Hsp70 expression and S. Enteritidis count.…”

“…The Hsp70 functions in the protection and folding of newly synthesized protein and the refolding of recently denatured proteins (Lindquist & Craig, 1988). It also imparts an anti-inflammatory role by inhibiting IL-8 production from macrophages and intestinal epithelial cells (Malago et al, 2005;Nemeth et al, 2006). IL-8 is known as a chemokine that recruits polymorphonuclear leukocytes to inflammatory sites*a response that is vital to the inflammatory diarrhoea caused by salmonella infection .…”

Probiotic bacteria are antagonistic to Salmonella enterica and Campylobacter jejuni and influence host lymphocyte responses in human microbiota‐associated immunodeficient and immunocompetent mice

“…The heat-killed mixture of L. acidophilus strains was unable to affect the invasion of Caco-2 cells by S. enterica serotype Typhimurium but mouse RAW 264.7 cells expressed tumor necrosis factor-a (TNF-a) and had increased nitric oxide production and phagocytic activity in response to the heat-killed lactobacilli. In a different study, culture supernatants from L. casei, L. curvatus, and L. plantarum inhibited S. enterica serotype Enteritidis from invading Caco-2 cells [45]. This was concomitant with reduced IL-8 expression by Caco-2 cells.…”

<i>Lactobacillus rhamnosus</i> GG and <i>Lactobacillus casei</i> Suppress <i>Escherichia coli</i>-Induced Chemokine Expression in Intestinal Epithelial Cells

“…Lastly, the induction of Hsp70 by L. casei was reported to be critical for the inhibition of Salmonella -induced CXCL8 induction [57]. Actually, the mRNA expression of 2 major components of Hsp70, HSPA1 and HSPA6, in Caco-2 cells was induced by 10 10 CFU/ml or higher concentrations of heat-killed LGG.…”