Chemokines and Antimicrobial Peptides Have a cag -Dependent Early Response to Helicobacter pylori Infection in Primary Human Gastric Epithelial Cells

Abstract

e Helicobacter pylori infection systematically causes chronic gastric inflammation that can persist asymptomatically or evolve toward more severe gastroduodenal pathologies, such as ulcer, mucosa-associated lymphoid tissue (MALT) lymphoma, and gastric cancer. The cag pathogenicity island (cag PAI) of H. pylori allows translocation of the virulence protein CagA and fragments of peptidoglycan into host cells, thereby inducing production of chemokines, cytokines, and antimicrobial peptides. In order to characterize the inflammatory response to H. pylori, a new experimental protocol for isolating and culturing primary human gastric epithelial cells was established using pieces of stomach from patients who had undergone sleeve gastrectomy. Isolated cells expressed markers indicating that they were mucin-secreting epithelial cells. Challenge of primary epithelial cells with H. pylori B128 underscored early dose-dependent induction of expression of mRNAs of the inflammatory mediators CXCL1 to -3, CXCL5, CXCL8, CCL20, BD2, and tumor necrosis factor alpha (TNF-␣). In AGS cells, significant expression of only CXCL5 and CXCL8 was observed following infection, suggesting that these cells were less reactive than primary epithelial cells. Infection of both cellular models with H. pylori B128⌬cagM, a cag PAI mutant, resulted in weak inflammatory-mediator mRNA induction. At 24 h after infection of primary epithelial cells with H. pylori, inflammatory-mediator production was largely due to cag PAI substrate-independent virulence factors. Thus, H. pylori cag PAI substrate appears to be involved in eliciting an epithelial response during the early phases of infection. Afterwards, other virulence factors of the bacterium take over in development of the inflammatory response. Using a relevant cellular model, this study provides new information on the modulation of inflammation during H. pylori infection.

In vitro culture and phenotypic and molecular characterization of gastric stem cells from human stomach

“…A cag PAI‐dependent induction of chemokine and MMP expression and of CXCL8 secretion by EPs was also observed at 24 hour postinfection (Figs S1–S5). Using our previously published model of primary gastric mucous epithelial cells, no induction of MMP1, MMP3, and IL‐33 by H. pylori was observed (data not shown).…”

“…We further studied some biological properties of EPs. Unlike primary mucous epithelial cells, which have a slow rate of proliferation in vitro and can be maintained in culture up to 10 days, isolated EPs display a high proliferation rate (as the AGS gastric cancer cell line) and can be passaged many times. EPs derived from GSCs can constitute a pertinent cellular model to investigate H. pylori infection.…”

“…Previous studies of gastric functions and diseases have been hampered by a lack of extended epithelial cell cultures. Recently, different models of primary gastric cell culture have been developed . From mouse stomach, a three‐dimensional culture of gastric organoids has been established, and a population of LGR5+ stem cells able to generate long‐lived organoid structure was described .…”

Enemy attraction: bacterial agonists for leukocyte chemotaxis receptors

“…pylori is a Gram-negative gastric colonizer with an ability to cause inflammation that contributes to the development of gastric ulcers and gastric cancer 93,94 . It is possible that the bacteria may benefit from the induction of the host pro-inflammatory responses 95 (2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20) reaches the extracellular space by autolysis, which is a process that leads to the release of many cytoplasmic proteins in H. pylori 98,99 . Proteins released by autolysis can retain their formylated N-termini, which is a probable reason for previous reports on chemo attractant activities of H. pylori proteins, such as urease 100 and an intracellular iron storage protein, the neutrophil-activating protein (HP-NAP) 101 .…”

Pathogenesis of Helicobacter pylori Infection

“…The results also suggested that CagA might result in the inactivation of RAD51 and reduced activity of DSB repair via homologous recombination of host cells, after infection with cag ‐positive strains. Regarding cag PAI functionality in the inflammatory response to H. pylori infection, the cag PAI has been reported to be responsible for the early induction of inflammatory mediators during infection, such as chemokine CXCL1‐3, CXCL5, CXCL8, CLL20, beta‐defensin 2 (BD2), and tumor necrosis factor‐alpha (TNF‐α) . While the cag PAI was highlighted as the leading factor involved in eliciting epithelial response during the early phase of infection, other virulence factors appear to take over later in the development of inflammatory response.…”