Lactobacillus reuteri Inhibition of Enteropathogenic Escherichia coli Adherence to Human Intestinal Epithelium

Abstract

Enteropathogenic Escherichia coli (EPEC) is a major cause of diarrheal infant death in developing countries, and probiotic bacteria have been shown to provide health benefits in gastrointestinal infections. In this study, we have investigated the influence of the gut symbiont Lactobacillus reuteri on EPEC adherence to the human intestinal epithelium. Different host cell model systems including non-mucus-producing HT-29 and mucus-producing LS174T intestinal epithelial cell lines as well as human small intestinal biopsies were used. Adherence of L. reuteri to HT-29 cells was strain-specific, and the mucus-binding proteins CmbA and MUB increased binding to both HT-29 and LS174T cells. L. reuteri ATCC PTA 6475 and ATCC 53608 significantly inhibited EPEC binding to HT-29 but not LS174T cells. While pre-incubation of LS174T cells with ATCC PTA 6475 did not affect EPEC attaching/effacing (A/E) lesion formation, it increased the size of EPEC microcolonies. ATCC PTA 6475 and ATCC 53608 binding to the mucus layer resulted in decreased EPEC adherence to small intestinal biopsy epithelium. Our findings show that L. reuteri reduction of EPEC adhesion is strain-specific and has the potential to target either the epithelium or the mucus layer, providing further rationale for the selection of probiotic strains.

The StcE metalloprotease of enterohaemorrhagicEscherichia colireduces the inner mucus layer and promotes adherence to human colonic epitheliumex vivo

“…n = 2 in duplicate for c and d. (e) A/E lesion formation was assessed by immunofluorescence staining and expressed as percentage of bacteria associated with actin pedestals relative to the total number of adherent bacteria, **p < 0.01, *p < 0.05 produce MUC2 glycoproteins (van Klinken et al, 1996), we found that EHEC O157:H7 prototype strains adhered better to this cell line compared to mucus-deficient Caco-2 and HT-29 cells. A similar phenotype has recently been reported for the related A/E pathogen enteropathogenic E. coli, which demonstrated increased binding to LS174T versus HT-29 cells (Walsham et al, 2016). In addition, adhesion of Salmonella enterica to mucus-producing HT-29 MTX cells was significantly increased compared to mucus-deficient HT-29 and Caco-2 cells (Gagnon, Zihler Berner, Chervet, Chassard, & Lacroix, 2013).…”

“…In addition, most human cell line models used to study EHEC infection (e.g. T84, Caco‐2, and HT‐29 colon carcinoma cells) are devoid of a MUC2‐containing mucus layer (Navabi, McGuckin, & Lindén ; van Klinken et al, ; Walsham et al, ). Using goblet cell‐like LS174T colon carcinoma cells which produce MUC2 glycoproteins (van Klinken et al, ), we found that EHEC O157:H7 prototype strains adhered better to this cell line compared to mucus‐deficient Caco‐2 and HT‐29 cells.…”

“…This is in contrast to previous studies demonstrating increased MUC2 gene expression in HT‐29 cells infected with EHEC (Xue et al, ). This discrepancy is likely related to the difference in cell line models, and as HT‐29 cells do not express MUC2 glycoproteins (Huet et al, ; Walsham et al, ), the relevance of this finding remains questionable.…”

“…In addition, most human cell line models used to study EHEC infection (e.g. T84, Caco-2, and HT-29 colon carcinoma cells) are devoid of a MUC2-containing mucus layer (Navabi, McGuckin, & Lindén 2013; van Klinken et al, 1996;Walsham et al, 2016). Using goblet cell-like LS174T colon carcinoma cells which FIGURE 4 EHEC StcE reduces mucin levels and promotes A/E lesion formation on LS174T cells.…”

Vitamin D/VDR, Probiotics, and Gastrointestinal Diseases

“…Various strains of probiotics could control microbiota, reduce colitis symptoms, protect barrier integrity and inhibit the release of proinflammatory cytokines [47] , resulting in preventing or repairing gut damage and inflammatory responses induced by pathogens [48] . However, the mechanisms behind these probiotics are complicated.…”