The Effects of Oral and Enteric Campylobacter concisus Strains on Expression of TLR4, MD-2, TLR2, TLR5 and COX-2 in HT-29 Cells

Abstract

Campylobacter concisus, a Gram-negative bacterium that colonizes the human oral cavity, has been shown to be associated with inflammatory bowel diseases (IBD). The effects of different C. concisus strains on intestinal epithelial expression of Toll like receptors (TLR) have not been investigated. This study examined the effects of C. concisus strains isolated from patients with IBD and controls on expression of TLR4, its co-receptor myeloid differentiation factor (MD)-2; TLR2, TLR5, cyclooxygenase-2 (COX-2) and interleukin (IL)-8 in HT-29 cells.Fourteen oral and enteric C. concisus strains isolated from patients with IBD and healthy controls were co-incubated with HT-29 cells. Expression of TLR4, MD-2, TLR2, TLR5 and COX-2 in HT-29 cells in response to C. concisus infection was examined by Western blot, flow cytometry analysis and immunofluorescent staining visualized by confocal microscope. Production of IL-8 was evaluated by enzyme-linked immunosorbent assay.Both oral and enteric C. concisus strains upregulated expression of TLR4 in HT-29 cells. The levels of glycosylated TLR4 (Gly-TLR4) and surface TLR4 induced by C. concisus strains isolated from patients with IBD were significantly higher than those induced by C. concisus strains isolated from the healthy controls. Four C. concisus strains isolated from patients with IBD induced more than two-fold increase of surface expression of MD-2. C. concisus did not affect expression of TLR2 and TLR5. All C. concisus strains induced production of IL-8 and COX-2 in HT-29 cells.This study shows that some C. concisus strains, most from patients with IBD, upregulate surface expression of TLR4 and MD-2 in HT-29 cells. These data suggest that a potential role of specific C. concisus strains in modulating the intestinal epithelial responses to bacterial LPS needs to be investigated.

Genome analysis of Campylobacter concisus strains from patients with inflammatory bowel disease and gastroenteritis provides new insights into pathogenicity

“…Previous studies found that some oral C. concisus strains or their toxins were able to damage the intestinal epithelial barrier and induce intestinal epithelial production of proinflammatory cytokines using cell line models111213. These data suggest that translocation of enteric virulent C. concisus strains from the human oral cavity to the intestinal tract may cause enteric diseases in some individuals.…”

Azathioprine, Mercaptopurine, and 5-Aminosalicylic Acid Affect the Growth of IBD-Associated Campylobacter Species and Other Enteric Microbes

“…In addition to IBD, C. concisus was frequently isolated from diarrheal stool samples, suggesting its involvement in diarrheal disease (Lindblom et al, 1995; Lastovica, 2006; Kalischuk and Inglis, 2011; Nielsen et al, 2013). Some oral C. concisus strains were found to invade human intestinal epithelial cells, further supporting the idea that they can cause enteric disease (Nielsen et al, 2011; Ismail et al, 2012, 2013). Various virulence factors were found in C. concisus , such as the zonula occludens toxin (Zot), which was shown to cause prolonged damage to the intestinal epithelial barrier, increase and enhance the response of macrophages to other bacterial species (Mahendran et al, 2013, 2016; Liu et al, 2016).…”

The Prevalence and Polymorphisms of Zonula Occluden Toxin Gene in Multiple Campylobacter concisus Strains Isolated from Saliva of Patients with Inflammatory Bowel Disease and Controls

“…Both oral and enteric C . concisus strains have been shown to induce the production of IL-8 in HT-29 cells [13,14,15]. Some oral C .…”

“…Some oral C . concisus strains isolated from patients with IBD were found to be invasive to Caco 2 cells and more effective in upregulating surface expression of Toll like receptor 4 in HT-29 cells [12,15]. Furthermore, increased intestinal epithelial apoptosis and permeability by some C .…”