CagL polymorphisms between East Asian and Western Helicobacter pylori are associated with different abilities to induce IL-8 secretion

The role of CEACAMs versus integrins in Helicobacter pylori CagA translocation: a systematic review

The delivery of Helicobacter pylori CagA into host cells was long believed to occur through the integrin cell surface receptors. However, the role of CEACAM receptors has recently been highlighted, instead. Here, we have categorized the existing experimental evidence according to whether deletion, upregulation, downregulation, or inhibition of the target ligands (T4SS or HopQ) or receptors (integrins or CEACAMs), result in alterations in CagA phosphorylation, cell elongation, or IL-8 production. According to our analysis, the statistics favor the essence of most of the T4SS constituents and the involvement of HopQ adhesin in all three functions. Concerning the integrin family, the collected data is controversial, but yielding towards it being dispensable or involved in CagA translocation. Yet, regarding cell elongation, more events are showing β1 integrin being involved, than αvβ4 being inhibitory. Concerning IL-8 secretion, again there are more events showing α5, β1 and β6 integrins to be involved, than those showing inhibitory roles for β1, β4 and β6 integrins. Finally, CEACAM 1, 3, and 5 are identified as mostly essential or involved in CagA phosphorylation, whereasCEACAM 4, 7, and 8 are found dispensable and CEACAM6 is under debate. Conversely, CEACAM1, 5 and 6 appear mostly dispensable for cell elongation. Noteworthy is the choice of cell type, bacterial strain, multiplicity and duration of infection, as well as the sensitivity of the detection methods, all of which can affect the variably obtained results.

Antibacterial and Immunoregulatory Effects of Metformin against Helicobacter pylori Infection in Rat Model

Introduction

Helicobacter pylori (H. pylori) induces gastritis by stimulating Th17 cells and related cytokines. The aim of our study was to investigate the synergistic effect of metformin with amoxicillin as an antibiotic in inhibiting H. pylori and modulating the immune response in a rat model.

Methods

Forty-five male Sprague-Dawley rats were divided into seven groups and infected with H. pylori. Over the course of 14 days, all animals were treated with metformin and amoxicillin alone and in combination. The antibacterial activity of metformin was evaluated by growth curves and colony counts. The immunoregulatory effect on Treg/Th17 balance was assessed by flow cytometry, and the cytokine profile of IL-17A, IL-1β, IL-6, IL-8, TGF-β, and IL-10 was determined by ELISA. The effect of metformin on gene expression of cagA and IL-8 was investigated by RT-PCR. Pathological changes were assessed by hematoxylin and eosin (H&E) staining and immunohistochemical (IHC) staining.

Results

Metformin showed weak antibacterial activity against clinically isolated H. pylori. However, the combination of metformin and amoxicillin (AMX) showed strong synergistic antibacterial activity (ΣFIC = 0.24). Compared with AMX, metformin reduced inflammation and tissue damage but resulted in increased bacterial growth. During metformin administration, both TGF-β levels and Treg cells increased dramatically (P = 0.002). In synergy with AMX, metformin decreased the effective dose of antibiotic to eradicate H. pylori.

Conclusions

The combination of metformin with potential antibiotics such as AMX had a positive effect on the relief of H. pylori-related inflammation by inducing Treg cells while successfully eliminating H. pylori.

New CagL Amino Acid Polymorphism Patterns of Helicobacter pylori in Peptic Ulcer and Non-Ulcer Dyspepsia

Background and Objectives: Helicobacter pylori infection is associated with chronic gastritis, ulcers, and gastric cancer. The H. pylori Type 4 secretion system (T4SS) translocates the CagA protein into host cells and plays an essential role in initiating gastric carcinogenesis. The CagL protein is a component of the T4SS. CagL amino acid polymorphisms are correlated with clinical outcomes. We aimed to study the association between CagL amino acid polymorphisms and peptic ulcer disease (PUD) and non-ulcer dyspepsia (NUD). Materials and Methods: A total of 99 patients (PUD, 46; NUD, 53) were enrolled and screened for H. pylori by qPCR from antrum biopsy samples. The amino acid polymorphisms of CagL were analyzed using DNA sequencing, followed by the MAFFT sequence alignment program to match the amino acid sequences. Results: Antrum biopsy samples from 70 out of 99 (70.7%) patients were found to be H. pylori DNA-positive. A positive band for cagL was detected in 42 out of 70 samples (PUD, 23; NUD, 19), and following this, these 42 samples were sequenced. In total, 27 different polymorphisms were determined. We determined three CagL amino acid polymorphism combinations, which were determined to be associated with PUD and NUD. Pattern 1 (K35/N122/V134/T175/R194/E210) was only detected in PUD patient samples and was related to a 1.35-fold risk (p = 0.02). Patterns 2 (V41/I134) and 3 (V41/K122/A171/I174) were found only in NUD patient samples and were linked to a 1.26-fold increased risk (p = 0.03). Conclusions: We observed three new patterns associated with PUD and NUD. Pattern 1 is related to PUD, and the other two patterns (Patterns 2 and 3) are related to NUD. The patterns that we identified include the remote polymorphisms of the CagL protein, which is a new approach. These patterns may help to understand the course of H. pylori infection.

Geographic diversity in Helicobacter pylori oipA genotype between Korean and United States isolates

Helicobacter pylori outer membrane inflammatory protein A (OipA) was originally named for its role in inducing inflammation in the host, as evidenced by high mucosal IL-8 levels. Expression of OipA is regulated by phase variation of a CT dinucleotide-repeat located in the 5' region of the gene. However, little is known about OipA geographic diversity across isolates. To address this gap, we conducted a large-scale molecular epidemiologic analysis using H. pylori clinical isolates obtained from two geographically distinct populations: Korea and the United States (US). Most Korean isolates (98.7%) possessed two copies of oipA located at two specific loci (A and B) while all US isolates contained only one copy of oipA at locus A. Furthermore, most Korean oipA (94.8%) possessed three or less CT repeats while most US oipA (96.6%) contained five or more CT repeats. Among the two copies, all Korean H. pylori possessed at least one oipA 'on' phase variant while the single copy of oipA in US isolates showed 56.2% 'on' and 43.8% 'off.' Thus, host differences seem to have driven geographic diversification of H. pylori across these populations such that OipA expression in US isolates is still regulated by phase variation with 5 or more CT repeats, while Korean isolates always express OipA; duplication of the oipA combined with a reduction of CT repeats to three or less ensures continued expression. En masse, these findings suggest that diversity in the oipA gene copy number, CT repeats, and phase variation among H. pylori from different populations may confer a benefit in adaptation to particular host populations.