Enterococcus faecalis Strains Differentially Regulate Alix/AIP1 Protein Expression and ERK 1/2 Activation in Intestinal Epithelial Cells in the Context of Chronic Experimental Colitis

Abstract

Monoassociation of germfree Interleukin 10 gene deficient (IL-10-/-) 129SvEv but not wild-type mice with Enterococcus faecalis induces severe chronic colitis. Bacterial strain-specific effects on the development of chronic intestinal inflammation are not understood. We investigated the molecular mechanisms of E. faecalis OG1RF (human clinical isolate, colitogenic) and E. faecalis ms2 (endogenous isolate from an IL-10-/- mouse) in initiating chronic experimental colitis using IL-10-/- mice. Monoassociation of IL-10-/- mice for 14 weeks revealed significant differences in colonic inflammation (3.6 +/- 0.2 and 2.4 +/- 0.6 for OG1RF and ms2, respectively) (n = 5 mice in each group) (histological scoring (0-4)). Consistent with the tissue pathology, gene expression of the pro-inflammatory chemokine interferon-gamma inducible protein-10 (IP-10) was significantly higher in intestinal epithelial cells (IEC) derived from E. faecalis OG1RF monoassociated IL-10-/- mice. We further compared the differentially E. faecalis induced colitis on the epithelial level by 2D-SDS PAGE coupled with MALDI-TOF MS. Proteome analysis identified 13 proteins which were differentially regulated during disease progression in the epithelium of E. faecalis-monoassociated IL-10-/- mice. Regulation of Alix/AIP1 protein expression and ERK1/2 phosphorylation was validated in primary IEC and epithelial cell lines, suggesting a protective role for Alix/AIP1 in the process of disease progression. Alix/AIP1 protein expression was further characterized in epithelial cell lines using siRNA-mediated knock-down. Our study demonstrates E. faecalis strain-specific induction of colitis in IL-10-/- mice after 14 weeks of monoassociation. Our study suggests that Alix/AIP1 protein expression and ERK1/2 activation are decreased in severe colitis.

Bacterially-Associated Transcriptional Remodelling in a Distinct Genomic Subtype of Colorectal Cancer Provides a Plausible Molecular Basis for Disease Development

“…Furthermore, we observed that CXCL10 was upregulated in E . faecalis + CRCs (FDR = 0.009, FC = 5.8), consistent with its reported upregulation in Enterococcus -administered IL-10 -/- mice [21,22]. In addition, BMI1 polycomb ring finger oncogene—an intestinal stem cell marker that is overexpressed in various cancers [23]–was upregulated two-fold in E .…”

In Vivo Assessment of Growth and Virulence Gene Expression during Commensal and Pathogenic Lifestyles of luxABCDE -Tagged Enterococcus faecalis Strains in Murine Gastrointestinal and Intravenous Infection Models

“…Hoffmann et al demonstrated the involvement of E. faecalis as a trigger of proinflammatory intestinal processes and colonic tissue pathology in the bowel of disease-susceptible mice (42,43). Although little is known about the contribution of enterococcal genetic traits to the development of intestinal pathologies, gelatinase production has been shown to promote the development of chronic gut inflammation by increasing the permeability of intestinal epithelial cells (44).…”

Impact of a probiotic Enterococcus faecalis in a gnotobiotic mouse model of experimental colitis

“…The probiotic E. faecalis (in figures designated as pro) is a component of the pharmaceutical preparation Symbioflor s 1, which is produced by SymbioPharm (Herborn). Enterococcus strains were cultured as described previously [23]. Cell cultures including the IEC line Mode K and mouse embryonic fibroblasts (MEFs) were stimulated with E. faecalis using a multiplicity of infection (moi; bacteria to epithelial cell ratio) of 30.…”

“…2-DE and identification of differentially regulated proteins was carried out as described earlier [23]. Briefly, IEF was performed with an IPGphor 2, using anodic cup loading of 500 mg protein per IPG strip.…”

“…However, in IL-10 À/À mice monocolonization with the welldescribed human oral isolate E. faecalis OG1RF was sufficient to induce severe colitis after 14 wk [21,22]. Recently, we were able to show that monocolonization with an endogenous E. faecalis isolate derived from an IL-10 À/À mouse induced only moderate colitis after 14 wk [23]. Therefore, we investigate here whether monocolonization with a probiotic E. faecalis strain leads to significantly reduced pathology scores in disease-susceptible IL-10 À/À mice compared to E. faecalis OG1RF.…”