Effect of Vibrio cholerae on Chemokine Gene Expression in HT29 cells and its Modulation by Lactobacillus GG

Abstract

Epithelial cells participate in the innate immune response to pathogenic bacteria by elaborating chemokines. This study examined the effect of Vibrio cholerae and Lactobacillus rhamnosus GG on inflammatory chemokine gene expression in the HT29 human intestinal epithelial cell line. HT29 cells were exposed to V. cholerae 0139, Lactobacillus or both for 2 h and cultured further thereafter for 4 h. RNA was extracted from the cells and expression of genes for chemokines and related molecules was quantitated by real time PCR using a pathway‐focused PCR array. TLR4 was silenced using shRNA and output of interleukin‐8 (IL‐8) into the media quantitated with and without V. cholerae exposure. NFκB and p38 MAP kinase activation were determined by immunoblotting for IκBα and phosphorylated p38. Vibrio cholerae significantly upregulated gene expression for the neutrophil chemoattractant CXCL chemokines, IL‐8, CXCL and CXCL in HT29 cells, while downregulating the expression of macrophage‐attracting C‐C chemokines. TLR4 silencing did not reduce IL‐8 output from HT29 cells in response to V. cholerae. IκBα degradation was noted in the HT29 cells soon after exposure to V. cholerae and this recovered over time after removal of bacteria. p38 MAP kinase activation was not noted. Vibrio cholerae upregulated the expression of neutrophil attractant chemokines, most prominently IL‐8, in HT29 cells, but downregulated macrophage‐attracting chemokines. Probiotic lactobacilli modulated the IL‐8, but not the other chemokine gene changes, in response to V. cholerae.

Immunomodulatory Properties of Fermented Soy and Dairy Milks Prepared with Lactic Acid Bacteria

“…Certain strains of LAB have been reported to modulate IEC signaling and NFκB activity (Riedel and others 2006; Tien and others 2006), and it has recently been suggested that this may be linked to the production of short‐chain fatty acids by LAB, in turn influencing immunomodulatory activity (Kumar and others 2009). Selected LAB strains have also been shown to down‐regulate IEC IL‐8 production (Bai and others 2004; Riedel and others 2006; Candela and others 2008; Imaoka and others 2008; Nandakumar and others 2009), a finding consistent with our observations for the soy and milk ferment bioactivity reported here, and with our earlier observations (Wallace and others 2003; Wood and others 2007). These results support the concept that LAB can produce a variety of bioactive components through fermentation, with a range of potential physiological effects.…”

“…However, due to differences in sensitivity observed between the 2 IEC lines in this study, definitive explanations for observed differences and final judgments about which ferment is the most useful await precise elucidation of underlying mechanisms of the ferment components on IEC. Several studies, including our previous reasearch with these strains, have shown that concurrent administration of LAB with pro‐inflammatory challenge is effective in reducing IEC IL‐8 production (Wood and others 2007; Ko and others 2007; Candela and others 2008; Nandakumar and others 2009). Preincubation of IEC with certain LAB prior to pro‐inflammatory challenge has also been reported to down‐regulate IL‐8 production (Bai and others 2004; Tien and others 2006); however, these studies did not compare the effects of preincubation relative to co‐incubation.…”

Capability of exopolysaccharide-producing Lactobacillus paraplantarum BGCG11 and its non-producing isogenic strain NB1, to counteract the effect of enteropathogens upon the epithelial cell line HT29-MTX

“…rhamnosus GG, pointed to the opposite direction; the production of IL-8 promoted by enteropathogens was stimulated in the presence of the three lactobacilli, whereas the purified ropy EPS-CG11 had no effect itself, probably, because it would make difficult the contact between the bacteria and the intestinal epithelium. In this regard, we can find in literature data supporting our results, that is a lactobacilli-mediated induction of IL-8 secretion (Kim et al, 2008;Seifert et al, 2010;Vizoso-Pinto et al, 2007); but also on the contrary, a down regulation of IL-8 production promoted by lactobacilli (Candela et al, 2008;Dhanani & Bagchi, 2013;Nandakumar et al, 2009;O'Hara et al, 2006). These apparently contradictory results indicates that the capability to modulate the levels of this chemokine is highly dependent on the Lactobacillus strain considered and, probably, dependent as well on the IL-8 inductor pathogen.…”

Inhibition of Streptococcus pneumoniae adherence to human epithelial cells in vitro by the probiotic Lactobacillus rhamnosus GG

“…LGG can modulate host cell production of IL-6 [31,32] and IL-8 [33,34] following exposure to pathogens or microbial antigens, such as flagellin, both in vivo and in vitro . Therefore, we hypothesized that exposure to LGG would reduce IL-6 and IL-8 production by epithelial cells.…”