Helicobacter pylori and gastrointestinal tract adenocarcinomas

Involvement of NF-κB signaling pathway in the regulation of PRKAA1-mediated tumorigenesis in gastric cancer

AMP-activated alpha 1 catalytic subunit (PRKAA1) is one of the subunits of the mammalian 5'-AMP-activated protein kinase (AMPK) playing an important role in maintaining intracellular energy metabolism and associating with the risk of gastric cancer (GC). This paper aims to uncover the influences of PRKAA1 on the tumorigenesis of GC, as well as the underlying mechanisms. We found that Helicobacter pylori (H. pylori) infection markedly increased p-NF-κBp50 and NF-κBp50 expression, along with the PRKAA1 expression, which was inhibited by NF-κBp50 knockdown. NF-κBp50 and PRKAA1 expression were lower in non-tumor gastric tissues compared with that in GC tumor tissues. Up-regulation of PRKAA1 expression was correlated with poor survival in GC patients. MKN-45 and BGC-823 cells stably knockdown of PRKAA1 were transplanted into nude mice and observed the decreased cell metastasis in the lungs. PRKAA1 knockdown in GC cells showed significant decreases in the cell invasion and migration and inhibited MMP-2 expression and NF-κB activation, whereas PRKAA1 involved in NF-κBp50 mediated GC cell invasion and migration. In conclusion, our findings suggest the involvement of NF-κBp50 in the regulation of PRKAA1 in GC tumorigenesis.

Unique responses of Helicobacter pylori to exogenous hydrophobic compounds

Helicobacter pylori is a pathogen responsible for peptic ulcers and gastric cancers in human. One of the unique biological features of this bacterium is a membrane lipid composition significantly differed from that of typical Gram-negative bacteria. Due to its unique lipid composition, the responses of H. pylori to various exogenous lipophilic compounds significantly differ from the responses of typical Gram-negative bacteria to the same lipophilic compounds. For instance, some steroidal compounds are incorporated into the biomembranes of H. pylori through the intermediation of the myristoyl-phosphatidylethanolamine (PE). In addition, H. pylori shows high susceptibility to bacteriolytic action of lipids such as 3-carbonyl steroids, vitamin D, and indene compounds. These lipids are also considered to interact with myristoyl-PE of H. pylori membranes, and to ultimately confer the bactericidal action to this bacterium. In this study we summarize the lipids concerned with H. pylori and suggest the possibility of the development of chemotherapeutic medicines that act on the membrane lipid component of H. pylori.

Prospects of NSAIDs administration as double-edged agents against endometrial cancer and pathological species of the uterine microbiome

Many types of cancers, including endometrial cancer, were found to have cyclooxygenase-2 (COX-2) overexpression. Because this enzyme belongs to the group of pro-inflammatory enzymes, so-called NSAIDs (non-steroidal anti–inflammatory drugs) directly inhibit its activity. An increasing number of reports on COX-2 involvement in cancer, as well as on the role of microbiota in abnormal metabolism and signaling of cells, forces the development of new NSAID types. Besides, NSAIDs can affect some bacteria, which are vaginal/endometrial microbiome members. The overgrowth of those species was found to be a major cause of some uterus diseases. Those infections can lead to chronic inflammatory response and suppress anti-tumorigenic cell pathways. The purpose of this review is to highlight the COX-2 enzyme role in endometrial cancer, the potential effect of the endometrial microbiome on COX-2 enzyme overexpression, and the prospects of NSAIDs use in terms of this type of cancer.

High expression of Helicobacter pylori VapD in both the intracellular environment and biopsies from gastric patients with severity

Helicobacter pylori is a Gram-negative bacterium that causes chronic atrophic gastritis and peptic ulcers and it has been associated with the development of gastric adenocarcinoma and mucosa-associated lymphoid tissue (MALT). One of the more remarkable characteristics of H. pylori is its ability to survive in the hostile environment of the stomach. H. pylori regulates the expression of specific sets of genes allowing it to survive high acidity levels and nutrient scarcity. In the present study, we determined the expression of virulence associated protein D (VapD) of H. pylori inside adenocarcinoma gastric (AGS) cells and in gastric biopsies. Using qRT-PCR, VapD expression was quantified in intracellular H. pylori-AGS cell cultures at different time points and in gastric mucosa biopsies from patients suffering from chronic atrophic gastritis, follicular gastritis, peptic ulcers, gastritis precancerous intestinal metaplasia and adenocarcinoma. Our results show that vapD of H. pylori presented high transcription levels inside AGS cells, which increased up to two-fold above basal values across all assays over time. Inside AGS cells, H. pylori acquired a coccoid form that is metabolically active in expressing VapD as a protection mechanism, thereby maintaining its permanence in a viable non-cultivable state. VapD of H. pylori was expressed in all gastric biopsies, however, higher expression levels (p = 0.029) were observed in gastric antrum biopsies from patients with follicular gastritis. The highest VapD expression levels were found in both antrum and corpus gastric biopsies from older patients (>57 years old). We observed that VapD in H. pylori is a protein that is only produced in response to interactions with eukaryotic cells. Our results suggest that VapD contributes to the persistence of H. pylori inside the gastric epithelial cells, protecting the microorganism from the intracellular environment, reducing its growth rate, enabling long-term infection and treatment resistance.

Can Natural Products Suppress Resistant Helicobacter pylori to Fight Against Gastric Diseases in Humans?

More than 50% of the world's population is infected with Helicobacter pylori. H. pylori is the major causative agent of gastric ulcers and gastric cancer. H. pylori eradication using antibiotics either alone or together with a proton pump inhibitor is the primary strategy to decrease the incidence of gastric cancer. Although eradication therapy is effective, there are significant adverse effects and more importantly, resistance to antibiotics occurs, which represents a major therapeutic challenge. Multiple natural products have been shown to suppress H. pylori both in vitro and in animal model systems. However, only a handful of natural products have been evaluated in human clinical trials. The focus of this review is to summarize the results of published human clinical trials to assess the ability of natural products to reduce or eliminate H. pylori infections. Current evidence suggests that these products appear to have great potential to be developed as pharmaceutical candidates for eradication of H. pylori, hopefully both antibiotic-sensitive and antibiotic-resistant strains. Frequent consumption of locally produced foodstuff for controlling H. pylori infection in different countries around the world may well be a feasible long-term solution to fight against this worldwide prevalent pathogen.

Precancerous Gastric Lesions with Helicobacter pylori vacA +/babA2+/oipA + Genotype Increase the Risk of Gastric Cancer

Objective

The clinical outcomes of gastric diseases such as chronic gastritis, peptic ulcer, and gastric cancer have been attributed to the interplay of virulence factors of Helicobacter pylori (H. pylori), host genetic susceptibility, and host immune responses. This study investigated the presence of cagA, vacA, iceA2, babA2, and oipA genes and their association with clinical outcomes.

Methods

Chronic gastritis, atrophic gastritis, and intestinal metaplasia specimens were obtained from patients who underwent endoscopy and surgical resection between January 2017 and December 2018; specimens from gastric cancer patients treated between January 2014 and December 2018 were also added. H. pylori), host genetic susceptibility, and host immune responses. This study investigated the presence of cagA, vacA, iceA2, babA2, and oipA genes and their association with clinical outcomes. H. pylori), host genetic susceptibility, and host immune responses. This study investigated the presence of

Results

H. pylori), host genetic susceptibility, and host immune responses. This study investigated the presence of vacA, babA2, and oipA genes and their association with clinical outcomes. vacA, babA2, and oipA genes and their association with clinical outcomes. P=0.033, OR = 2.64; 95% CI = 1.44–4.82, P=0.033, OR = 2.64; 95% CI = 1.44–4.82, P=0.033, OR = 2.64; 95% CI = 1.44–4.82, H. pylori vacA⁺/babA2, and oipA genes and their association with clinical outcomes. P=0.033, OR = 2.64; 95% CI = 1.44–4.82,

Conclusion

In this present study, we reported on the virulence genes of H. pylori infection to reveal their association with increased risk of chronic gastritis, precancerous gastric lesions, and gastric cancer. Precancerous gastric lesions with H. pylori vacA+/babA2+/oipA+ genotype increased the risk of gastric cancer.H. pylori), host genetic susceptibility, and host immune responses. This study investigated the presence of H. pylori vacA⁺/babA2, and oipA genes and their association with clinical outcomes.

The HopQ-CEACAM Interaction Controls CagA Translocation, Phosphorylation, and Phagocytosis of Helicobacter pylori in Neutrophils

Helicobacter pylori is highly adapted to humans and evades host immunity to allow its lifelong colonization. However, the H. pylori mouse model is artificial for H. pylori, and few adapted strains allow gastric colonization. Here, we show that human or CEACAM-humanized, but not mouse neutrophils are manipulated by the H. pylori HopQ-CEACAM interaction. Human CEACAMs are responsible for CagA phosphorylation, activation, and processing in neutrophils, whereas CagA translocation and tyrosine phosphorylation in DCs and macrophages is independent of the HopQ-CEACAM interaction. H. pylori affects the secretion of distinct chemokines in CEACAM-humanized neutrophils and macrophages. Most importantly, human CEACAMs on neutrophils enhance binding, oxidative burst, and phagocytosis of H. pylori and enhance bacterial survival in the phagosome. The H. pylori-CEACAM interaction modulates PMNs to reduce the H. pylori CagA translocation efficiency in vivo and to fine-tune the expression of CEACAM receptors on neutrophils to limit translocation of CagA and gastric pathology.

The cag type IV secretion system (cag-T4SS) of Helicobacter pylori exploits specific cellular carcinoembryonic antigen-related cell adhesion molecules (CEACAMs), such as CEACAM1, -3, -5, and -6, as cellular receptors for CagA translocation into human gastric epithelial cells. We studied the interaction of H. pylori with human CEACAM1, CEACAM3, and CEACAM6 receptors (hCEACAMs) expressed on myeloid cells from CEACAM-humanized mice. Human and CEACAM-humanized mouse polymorphonuclear neutrophils (PMNs) allowed a specific HopQ-dependent interaction strongly enhancing CagA translocation. Translocated CagA was tyrosine phosphorylated, which was not seen in wild-type (wt) murine neutrophils. In contrast, human or murine bone marrow-derived macrophages and dendritic cells (DCs) revealed a low hCEACAM expression and bacterial binding. CagA translocation and tyrosine-phosphorylation was low and independent of the HopQ-CEACAM interaction. Neutrophils, but not macrophages or DCs, from CEACAM-humanized mice, significantly upregulated the proinflammatory chemokine MIP-1α. However, macrophages showed a significantly reduced amount of CXCL1 (KC) and CCL2 (MCP-1) secretion in CEACAM-humanized versus wt cells. Thus, H. pylori, via the HopQ-CEACAM interaction, controls the production and secretion of chemokines differently in PMNs, macrophages, and DCs. We further show that upon H. pylori contact the oxidative burst of neutrophils and phagocytosis of H. pylori was strongly enhanced, but hCEACAM3/6 expression on neutrophils allowed the extended survival of H. pylori within neutrophils in a HopQ-dependent manner. Finally, we demonstrate that during a chronic mouse infection, H. pylori is able to systemically downregulate hCEACAM1 and hCEACAM6 receptor expression on neutrophils, probably to limit CagA translocation efficiency and most likely gastric pathology.

Antibacterial effect of indene on Helicobacter pylori correlates with specific interaction between its compound and dimyristoyl-phosphatidylethanolamine

Recent studies by our group have suggested that the vitamin D₃ decomposition product VDP1 [(1R,3aR,7aR)-1-[(1R)-1,5-dimethylhexyl]octahydro-7a-methyl-4H-inden-4-one] confers the potent bactericidal action to Helicobacter pylori by targeting the membranal dimyristoyl-phosphatidylethanolamine (di-14:0 PE). In this study we synthesized a new VDP1 derivative to advance further investigation as for the correlative relationship between VDP1 structure and anti-H. pylori activity or PE vesicle collapse induction activity. The derivative VD3-7 [(1R,7aR)-4-fluoro-7a-methyl-1-((R)-6-methylheptan-2-yl)octahydro-1H-indene] retained a fluorine atom in place of the oxygen atom of VDP1. The fluorination of the carbonyl portion of VDP1 forfeited the effective anti-H. pylori activity. We, therefore, prepared Coomassie brilliant blue (CBB)-containing unilamellar vesicles consisting of various PE molecular species, and examined the vesicle collapse induction activity of either VDP1 or VD3-7 by detecting the CBB eluted from the PE unilamellar vesicles. VDP1 strongly induced CBB elution from the unilamellar vesicles of rectus-PE retaining the same two fatty acid side-chains shorter than carbon numbers 14, indicating that VDP1 specifically disrupted the vesicular conformation of those PE unilamellar vesicles. Meanwhile, VD3-7 had no influence on the structural stability of any PE unilamellar vesicles. This study obtained additional evidence that VDP1 acts as a bactericidal agent on H. pylori by targeting the membranal di-14:0 PE.

Roles of microbiota in response to cancer immunotherapy

Immunotherapy, which shows great promise for treating patients with metastatic malignancies, has dramatically changed the therapeutic landscape of cancer, particularly subsequent to the discovery of immune checkpoint inhibitors. However, the responses to immunotherapy are heterogeneous and often transient. More problematic is that a high proportion of patients with cancer are resistant to such therapy. Much effort has been expended to identify reliable biomarkers that accurately predict clinical responses to immunotherapy. Unfortunately, such tools are lacking, and our knowledge of the mechanisms underlying its efficacy and safety is insufficient. The microbiota is increasingly recognized for its influence on human health and disease. Microbes create a pro- or an anti-inflammatory environment through complex interactions with host cells and cytokines. Emerging evidence indicates that microbes alter the efficacy and toxicity of immunotherapy by modulating the host's local and systemic immune responses. It is therefore critically important to exploit the microbiota to develop biomarkers as well as to identify therapeutic targets that can be applied to cancer immunotherapy. This review provides insights into the challenges that must be addressed to achieve these goals.

T4SS-dependent TLR5 activation by Helicobacter pylori infection

Toll-like receptor TLR5 recognizes a conserved domain, termed D1, that is present in flagellins of several pathogenic bacteria but not in Helicobacter pylori. Highly virulent H. pylori strains possess a type IV secretion system (T4SS) for delivery of virulence factors into gastric epithelial cells. Here, we show that one of the H. pylori T4SS components, protein CagL, can act as a flagellin-independent TLR5 activator. CagL contains a D1-like motif that mediates adherence to TLR5⁺ epithelial cells, TLR5 activation, and downstream signaling in vitro. TLR5 expression is associated with H. pylori infection and gastric lesions in human biopsies. Using Tlr5-knockout and wild-type mice, we show that TLR5 is important for efficient control of H. pylori infection. Our results indicate that CagL, by activating TLR5, may modulate immune responses to H. pylori.

Toll-like receptor TLR5 recognizes a domain, D1, that is present in flagellins of several pathogenic bacteria but not in Helicobacter pylori. Here, the authors show that TLR5 can be activated independently of flagellin by a component of the H. pylori type IV secretion system that contains a D1-like motif.

Hypothesis: Bacterial induced inflammation disrupts the orderly progression of the stem cell hierarchy and has a role in the pathogenesis of breast cancer

BACKGROUND

The hierarchical model of stem cell genesis is based on the idea that the number of cell divisions between the zygote and fully differentiated epithelial cells is kept close to the minimum, which is log to the base 2 of the total number of cells produced in a human lifetime. The model assumes the orderly progression of stem cell divisions requires precise control at every stage in development. If the orderly progression is maintained then cancer will be rare. A prediction of the model is that if the orderly progression of the stem cell hierarchy is disturbed by trauma, ulceration or inflammation then cancer will occur.

HYPOTHESIS

Bacterial induced inflammation in breast ducts disturbs the stem cell hierarchy and is a cause of breast cancer.

EVIDENCE

Mammalian milk is not sterile. It contains a range of bacteria, derived endogenously by the entero-mammary circulation. The dominant flora consists of lactose fermenting bacteria. Pregnancy and breast feeding reduce the risk of subsequent breast cancer. The implication is that a lactose fermenting bacterial flora in breast ducts is protective. Malignant and benign breast tissue contains bacteria derived endogenously, but studies so far have not revealed a specific flora associated with malignancy. Periodontitis is associated with oral, oesophageal, colonic, pancreatic, prostatic and breast cancer. The pathogenic bacteria which cause periodontitis spread endogenously to cause inflammation at other epithelial sites. Meta-analysis of epidemiological studies shows that the consumption of yoghurt is associated with a reduction in the risk of breast cancer.

CONCLUSION

The hypothesis, although not proven, is supported by the available evidence. Lactose fermenting bacteria protect but pathogenic bacteria which induce inflammation raise the risk of breast cancer. The consumption of yoghurt also appears to be protective.

Molecular anatomy and pathogenic actions of Helicobacter pylori CagA that underpin gastric carcinogenesis

Chronic infection with Helicobacter pylori cagA-positive strains is the strongest risk factor for gastric cancer. The cagA gene product, CagA, is delivered into gastric epithelial cells via the bacterial type IV secretion system. Delivered CagA then undergoes tyrosine phosphorylation at the Glu-Pro-Ile-Tyr-Ala (EPIYA) motifs in its C-terminal region and acts as an oncogenic scaffold protein that physically interacts with multiple host signaling proteins in both tyrosine phosphorylation-dependent and -independent manners. Analysis of CagA using in vitro cultured gastric epithelial cells has indicated that the nonphysiological scaffolding actions of CagA cell-autonomously promote the malignant transformation of the cells by endowing the cells with multiple phenotypic cancer hallmarks: sustained proliferation, evasion of growth suppressors, invasiveness, resistance to cell death, and genomic instability. Transgenic expression of CagA in mice leads to in vivo oncogenic action of CagA without any overt inflammation. The in vivo oncogenic activity of CagA is further potentiated in the presence of chronic inflammation. Since Helicobacter pylori infection triggers a proinflammatory response in host cells, a feedforward stimulation loop that augments the oncogenic actions of CagA and inflammation is created in CagA-injected gastric mucosa. Given that Helicobacter pylori is no longer colonized in established gastric cancer lesions, the multistep nature of gastric cancer development should include a “hit-and-run” process of CagA action. Thus, acquisition of genetic and epigenetic alterations that compensate for CagA-directed cancer hallmarks may be required for completion of the “hit-and-run” process of gastric carcinogenesis.

microRNAs Tune Oxidative Stress in Cancer Therapeutic Tolerance and Resistance

Relapsed disease following first-line therapy remains one of the central problems in cancer management, including chemotherapy, radiotherapy, growth factor receptor-based targeted therapy, and immune checkpoint-based immunotherapy. Cancer cells develop therapeutic resistance through both intrinsic and extrinsic mechanisms including cellular heterogeneity, drug tolerance, bypassing alternative signaling pathways, as well as the acquisition of new genetic mutations. Reactive oxygen species (ROSs) are byproducts originated from cellular oxidative metabolism. Recent discoveries have shown that a disabled antioxidant program leads to therapeutic resistance in several types of cancers. ROSs are finely tuned by dysregulated microRNAs, and vice versa. However, mechanisms of a crosstalk between ROSs and microRNAs in regulating therapeutic resistance are not clear. Here, we summarize how the microRNA-ROS network modulates cancer therapeutic tolerance and resistance and direct new vulnerable targets against drug tolerance and resistance for future applications.

Maturation of atypical ribosomal RNA precursors in Helicobacter pylori

In most bacteria, ribosomal RNA is transcribed as a single polycistronic precursor that is first processed by RNase III. This double-stranded specific RNase cleaves two large stems flanking the 23S and 16S rRNA mature sequences, liberating three 16S, 23S and 5S rRNA precursors, which are further processed by other ribonucleases. Here, we investigate the rRNA maturation pathway of the human gastric pathogen Helicobacter pylori. This bacterium has an unusual arrangement of its rRNA genes, the 16S rRNA gene being separated from a 23S-5S rRNA cluster. We show that RNase III also initiates processing in this organism, by cleaving two typical stem structures encompassing 16S and 23S rRNAs and an atypical stem–loop located upstream of the 5S rRNA. Deletion of RNase III leads to the accumulation of a large 23S-5S precursor that is found in polysomes, suggesting that it can function in translation. Finally, we characterize a cis-encoded antisense RNA overlapping the leader of the 23S-5S rRNA precursor. We present evidence that this antisense RNA interacts with this precursor, forming an intermolecular complex that is cleaved by RNase III. This pairing induces additional specific cleavages of the rRNA precursor coupled with a rapid degradation of the antisense RNA.

Role of Th22 cells in Helicobacter pylori-related gastritis and peptic ulcer diseases

Helicobacter pylori (H. pylori) has been shown to be one of the leading causes of peptic ulcer diseases (PUDs) and gastritis. T helper-22 (Th22) cells and its most important cytokine, interleukin-22 (IL-22) are importantly active in inflammation and inflammatory tissues. Since inflammation is one of the main attributes of infection caused by H. pylori and resulting complications (gastritis and gastrointestinal ulcer), this study was designed to evaluate the Th22 cells count and the IL-22 protein expression in people suffering from PUD and gastritis. The present study was conducted on 55 patients with gastritis, 47 patients with PUD and 48 uninfected subjects. After preparation of section and extraction of protein from antral biopsies, immunohistochemistry and western blot methods were used to evaluate the Th22 cells and IL-22 protein expression level, respectively. According to findings, the Th22 cells count and the IL-22 protein expression level in the infected subjects were siginficantly more than in the uninfected subjects. It should be noted that the Th22 cells count and the IL-22 protein expression level in the infected subjects with PUD were significantly greater than those in the infected subjects with gastritis. In addition, the Th22 cells count had positive correlation with the density of H. pylori, chronic inflammation score and acute inflammatory score in the infected subjects with PUD. The Th22 cells count had positive correlation with the Th17 cells count and inverse correlation with the Treg cells count in the infected subjects with PUD and gastritis. Our data demonstrated that abnormal hyper-activation of Th22 cells as well as its correlation with the Th17 cells during infection caused by H. pylori might damage tissues through immunopathological responses.

Hepatocyte Growth Factor in Blood and Gastric Cancer Risk: A Nested Case-Control Study

BACKGROUND

Potential of hepatocyte growth factor (HGF)-stimulating signaling pathways related to cytotoxin-associated gene A (CagA) to predict gastric cancer development has not been fully investigated.

METHODS

We conducted a nested case-control study consisting of 238 gastric cancer cases and 238 matched controls within the Korean Multicenter Cancer Cohort. Plasma HGF concentrations were measured with a human HGF ELISA. Odds ratios (OR) and 95% confidence intervals (CI) for gastric cancer development according to HGF level were calculated using conditional logistic regression model.

RESULTS

Sequential elevation of gastric cancer risk according to HGF level increase was observed (OR, 10.99; 95% CI, 4.91-24.62) for highest quartile HGF (≥364 pg/mL) versus lowest quartile HGF (<167 pg/mL). A significantly increased gastric cancer risk associated with high HGF level measured even 6 or more years prior to cancer diagnosis was also found. The group with both high risk of HGF and CagA-related genetic variants was associated with highest gastric cancer risk compared with the group with both low risk of HGF and genetic variants (P _interaction = 0.05). Model performance using HGF and CagA-related genetic variants to discriminate gastric cancer was fair [area under the curve of receiver operating characteristic (AUC-ROC), 0.71; 95% CI, 0.64-0.78] and significantly higher than that of model not including those biomarkers.

CONCLUSIONS

Our results suggest HGF as a potential biomarker to predict gastric cancer development.

IMPACT

These findings suggest HGF as a useful biomarker to predict gastric cancer risk. Further research to assess gastric cancer risk based on useful biomarkers, including HGF, may contribute to primary prevention of gastric cancer.

A Newly Discovered Drug Resistance Gene rfaF In Helicobacter pylori

BACKGROUND

The purpose of this study was to understand the function of rfaF gene in Helicobacter pylori antibiotic resistance.

METHODS

The gene homologous recombination method was used for knockout and complementation of H. pylori rfaF gene. Various constructed strains were analysed for drug sensitivity to amoxicillin (AMO), tetracycline (TET), clarithromycin (CLA), metronidazole (MET), levofloxacin (LEV), and chloramphenicol (CHL) by agar plate dilution method. Drug sensitivity was further confirmed using a growth inhibition curve. Ethidium bromide (EB) accumulation experiments were performed to assess cell membrane permeability. PCR and sequence analysis were used to detect the rfaF gene.

RESULTS

The minimum inhibitory concentrations (MIC) of TET, CHL, AMO, and CLA in 11,637 rfaF knockout strain (ΔrfaF strain) were 4, 4, 2, and 2 times higher than those in 11,637 wild type (WT) strain, respectively. A multidrug-resistant (MDR) ΔrfaF strain also displayed the same trend; however, the degrees of increase were relatively small. Growth inhibition experiments indicated that the growth of the 11,637 ΔrfaF strain was higher with antibiotics at the MIC of the 11,637 WT strain than that of 11,637 rfaF-complemented strain (ΔrfaF/rfaF strain), whereas the 11,637 WT strain did not exhibit any growth. The 11,637 ΔrfaF strain was significantly reduced compared with the cumulative EB fluorescence intensity of the 11,637 WT and of 11,637ΔrfaF/rfaF strain, and the same trend appeared in the MDR strain. Among the 10 clinical strains, 9 clinical strains were found to have mutations in the conserved sequence of rfaF amino acids.

CONCLUSION

We found a new drug resistance gene, rfaF, in H. pylori, which changes the permeability of cell membrane to confer cross-resistance to AMO, TET, CLA, and CHL and is involved in clinical strain drug resistance. It can be used as a drug target.

Bacterial Manipulation of Wnt Signaling: A Host-Pathogen Tug-of-Wnt

The host-pathogen interface is a crucial battleground during bacterial infection in which host defenses are met with an array of bacterial counter-mechanisms whereby the invader aims to make the host environment more favorable to survival and dissemination. Interestingly, the eukaryotic Wnt signaling pathway has emerged as a key player in the host and pathogen tug-of-war. Although studied for decades as a regulator of embryogenesis, stem cell maintenance, bone formation, and organogenesis, Wnt signaling has recently been shown to control processes related to bacterial infection in the human host. Wnt signaling pathways contribute to cell cycle control, cytoskeleton reorganization during phagocytosis and cell migration, autophagy, apoptosis, and a number of inflammation-related events. Unsurprisingly, bacterial pathogens have evolved strategies to manipulate these Wnt-associated processes in order to enhance infection and survival within the human host. In this review, we examine the different ways human bacterial pathogens with distinct host cell tropisms and lifestyles exploit Wnt signaling for infection and address the potential of harnessing Wnt-related mechanisms to combat infectious disease.

Characterization of a novel Helicobacter pylori East Asian-type CagA ELISA for detecting patients infected with various cagA genotypes

Currently, Western-type CagA is used in most commercial Helicobacter pylori CagA ELISA kits for CagA detection rather than East Asian-type CagA. We evaluated the ability of the East Asian-type CagA ELISA developed by our group to detect anti-CagA antibody in patients infected with different cagA genotypes of H. pylori from four different countries in South Asia and Southeast Asia. The recombinant CagA protein was expressed and later purified using GST-tag affinity chromatography. The East Asian-type CagA-immobilized ELISA was used to measure the levels of anti-CagA antibody in 750 serum samples from Bhutan, Indonesia, Myanmar, and Bangladesh. The cutoff value of the serum antibody in each country was determined via Receiver-Operating Characteristic (ROC) analysis. The cutoff values were different among the four countries studied (Bhutan, 18.16 U/mL; Indonesia, 6.01 U/mL; Myanmar, 10.57 U/mL; and Bangladesh, 6.19 U/mL). Our ELISA had better sensitivity, specificity, and accuracy of anti-CagA antibody detection in subjects predominantly infected with East Asian-type CagA H. pylori (Bhutan and Indonesia) than in those infected with Western-type CagA H. pylori predominant (Myanmar and Bangladesh). We found positive correlations between the anti-CagA antibody and antral monocyte infiltration in subjects from all four countries. There was no significant association between bacterial density and the anti-CagA antibody in the antrum or the corpus. The East Asian-type CagA ELISA had improved detection of the anti-CagA antibody in subjects infected with East Asian-type CagA H. pylori. The East Asian-type CagA ELISA should, therefore, be used in populations predominantly infected with East Asian-type CagA.

Immunoinformatics approaches to explore Helicobacter Pylori proteome (Virulence Factors) to design B and T cell multi-epitope subunit vaccine

Helicobacter Pylori is a known causal agent of gastric malignancies and peptic ulcers. The extremophile nature of this bacterium is protecting it from designing a potent drug against it. Therefore, the use of computational approaches to design antigenic, stable and safe vaccine against this pathogen could help to control the infections associated with it. Therefore, in this study, we used multiple immunoinformatics approaches along with other computational approaches to design a multi-epitopes subunit vaccine against H. Pylori. A total of 7 CTL and 12 HTL antigenic epitopes based on c-terminal cleavage and MHC binding scores were predicted from the four selected proteins (CagA, OipA, GroEL and cagA). The predicted epitopes were joined by AYY and GPGPG linkers. Β-defensins adjuvant was added to the N-terminus of the vaccine. For validation, immunogenicity, allergenicity and physiochemical analysis were conducted. The designed vaccine is likely antigenic in nature and produced robust and substantial interactions with Toll-like receptors (TLR-2, 4, 5, and 9). The vaccine developed was also subjected to an in silico cloning and immune response prediction model, which verified its efficiency of expression and the immune system provoking response. These analyses indicate that the suggested vaccine may produce particular immune responses against H. pylori, but laboratory validation is needed to verify the safety and immunogenicity status of the suggested vaccine design.

Antimicrobial activity of ellagic acid against Helicobacter pylori isolates from India and during infections in mice

Objectives

Because of the rise in antimicrobial resistance, an inexpensive, diet-based treatment against Helicobacter pylori infection would be of great interest. The present study was performed to assess the in vitro effects of ellagic acid against clinical H. pylori strains that were resistant to antibiotics used for therapy and also to observe the morphological structure following treatment with ellagic acid. The effectiveness of ellagic acid in eradicating H. pylori infection in a murine (C57BL/6) infection model, one of the standard inbred mouse lines often used for experimental infection, was also assessed.

Methods

A total of 55 strains were screened. The agar dilution method was used to determine the susceptibility of isolates to test compounds. Transmission electron microscopy was used to observe the morphology following treatment with ellagic acid. The antibacterial activity of ellagic acid in an H. pylori SS1-infected mouse model and its effect on gastric mucosal injury were determined by histology and PCR.

Results

Ellagic acid inhibited the growth of all 55 of the H. pylori strains tested. The MIC of ellagic acid ranged from 5 to 30 mg/L, showing its bactericidal properties in vitro. Ellagic acid also demonstrated anti-H. pylori efficacy in eradication of this organism in an in vivo model, as well as restitution and repair of H. pylori-induced gastric mucosal damage.

Conclusions

The present study paves the way for the preventive and therapeutic use of ellagic acid against H. pylori infection and, thus, ellagic acid can be considered a promising antibacterial agent against H. pylori-associated gastroduodenal diseases in humans.

The Role of the Lymphocyte Functional Crosstalk and Regulation in the Context of Checkpoint Inhibitor Treatment-Review

During the last decade, the dynamics of the cellular crosstalk have highlighted the significance of the host vs. tumor interaction. This resulted in the development of novel immunotherapeutic strategies in order to modulate/inhibit the mechanisms leading to escape of tumor cells from immune surveillance. Different monoclonal antibodies directed against immune checkpoints, e.g., the T lymphocyte antigen 4 and the programmed cell death protein 1/ programmed cell death ligand 1 have been successfully implemented for the treatment of cancer. Despite their broad activity in many solid and hematologic tumor types, only 20–40% of patients demonstrated a durable treatment response. This might be due to an impaired T cell tumor interaction mediated by immune escape mechanisms of tumor and immune cells as well as alterations in the composition of the tumor microenvironment, peripheral blood, and microbiome. These different factors dynamically regulate different steps of the cancer immune process thereby negatively interfering with the T cell –mediated anti-tumoral immune responses. Therefore, this review will summarize the current knowledge of the different players involved in inhibiting tumor immunogenicity and mounting resistance to checkpoint inhibitors with focus on the role of tumor T cell interaction. A better insight of this process might lead to the development of strategies to revert these inhibitory processes and represent the rational for the design of novel immunotherapies and combinations in order to improve their efficacy.

Current information on the association of Helicobacter pylori with autophagy and gastric cancer

Helicobacter pylori (H. pylori) is a Gram-negative bacterium and causative agent of gastric cancer. H. pylori induce defective autophagy or inhibit it by means of CagA and vacuolating cytotoxin A (VacA) toxins leading to the gastric cancer induction. Impaired or defective autophagy leads to the accumulation of cytotoxic materials, such as ROS and P62 that lead to increased mutations in the DNA, genome instability, and risk of cancer formation. H. pylori CagA may inhibit autophagy through the c-Met-PI3k/Akt-mTOR signaling pathway. However, VacA induces autophagy by some signaling pathways. In the gastric epithelial cells, VacA is a necessary and sufficient factor for the creation of autophagy. While CagA is a negative regulator of this phenomenon, the elimination of this gene from H. pylori has increased autophagy and the production of inflammatory cytokines is reduced. In gastrointestinal cancers, some of the microRNAs (miRNAs) act as tumor suppressors and some other are oncogenes by regulating various genes expression. H. pylori can also modify autophagy through a mechanism that includes the function of miRNAs. In autophagy, oncogenic miRNAs inhibit activation of some tumor suppressor signaling pathways (e.g., ULK1 complex, Beclin-1 function, and Atg4 messaging), whereas tumor suppressor miRNAs can block the activation of oncogenic signaling pathways. For instance, Beclin-1 is negatively regulated by miRNA-376b (oncogenic miRNA) and miRNA-30a (tumor suppressor miRNA). Similarly, Atg4 by miRNA-376b (oncogenic miRNA) and miRNA-101 (tumor suppressor miRNA). So, this apparent paradox can be explained as that both Beclin-1 and Atg4 play different roles in a particular cell or tissue.

Helicobacter pylori lipids can form ordered membrane domains (rafts)

Ordered lipid domains (rafts) are generally considered to be features of eukaryotic cells, but ordered lipid domains formed by cholesterol lipids have been identified in bacteria from the genus Borrelia, and similar cholesterol lipids exist in the bacterium Helicobacter pylori. To determine whether H. pylori lipids could form ordered membrane domains, we investigated domain formation in aqueous dispersions of H. pylori whole lipid extracts, individual H. pylori lipids, or defined mixtures of H. pylori lipids and other membrane-forming lipids. DPH (1,6-diphenyl-1,3,5-hexatriene) anisotropy measurements were used to assay membrane order and FRET (Förster resonance energy transfer) was used to detect the presence of co-existing ordered and disordered domains. We found that H. pylori membrane lipid extracts spontaneously formed lipid domains. Domain formation was more stable when lipids were extracted from H. pylori cells grown in the presence of cholesterol. Certain isolated H. pylori lipids (by themselves or when mixed with other lipids) also had the ability to form ordered domains. To be specific, H. pylori cholesteryl-6-O-tetradecanoyl-α-D-glucopyranoside (CAG) and cholesterol-6-O-phosphatidyl-α-D-glucopyranoside (CPG) had the ability to form and/or stabilize ordered domain formation, while H. pylori phosphatidylethanolamine did not, behaving similarly to unsaturated phosphatidylethanolamines. We conclude that specific H. pylori cholesterol lipids have a marked ability to form ordered lipid domains.

Long noncoding RNA THAP9-AS1 is induced by Helicobacter pylori and promotes cell growth and migration of gastric cancer

Background

Long noncoding RNAs (LncRNAs) have been confirmed to play crucial roles in cancer biology. Gastric cancer (GC) is the third leading cause of cancer related death, and Helicobacter pylori (H. pylori) is the major risk factor for GC. In this study, we focused on the roles of H. pylori-related lncRNAs in the progression of GC.

Method

Differentially expressed lncRNAs were identified through RNA-seq analysis of H. pylori-infected GC cells.

Results

We found that the expression of the lncRNA THAP9-AS1 was up-regulated after infection of GC cells with H. pylori and was higher in GC tissues than in gastritis tissues. Colony formation, CCK8 and transwell assays were executed to show that THAP9-AS1 can promote GC cell proliferation and migration in vitro. Our study identified the pro-oncogenic lncRNA THAP9-AS1, which has a higher expression level in GC tissues than in gastritis tissues and which promoted the proliferation and migration of GC cells in vitro.

Conclusion

These findings may provide a potential therapeutic target for H. pylori-associated GC.

SIRT1-targeted miR-543 autophagy inhibition and epithelial-mesenchymal transition promotion in Helicobacter pylori CagA-associated gastric cancer

Gastric cancer is an important cause of death worldwide with Helicobacter pylori (H. pylori) considered a leading and known risk factor for its development. More particularly and despite the underlying mechanisms not being very clear, studies have revealed that the H. pylori cytotoxin-associated gene A (CagA) protein plays a key role in this process. In this study it was found that H. pylori increased the expression of miR-543 in human gastric cancer tissue when compared with H. pylori-negative gastric cancer tissue samples. In vitro experiments showed that increased expression of miR-543 induced by CagA is a strong promoter of cell proliferation, migration, and invasion. Conversely, a miR-543 inhibitor suppressed or reversed these effects. It was furthermore found that silencing miR-543 inhibited autophagy and led to epithelial-mesenchymal transition (EMT) under in vitro. The mechanisms by which miR-543 targets SIRT1 to downregulate autophagy was also described. The results suggest that in the progression of H. pylori-associated gastric cancer, CagA induces overexpression of miR-543, which subsequently targets SIRT1 to suppress autophagy. This may be followed by increased expression of EMT causing cell migration and invasion. Consequently, miR-543 might be considered a therapeutic target for H. pylori-associated gastric cancer.

Current prevalence status of gastric cancer and recent studies on the roles of circular RNAs and methods used to investigate circular RNAs

Gastric cancer is a malignant tumor with the fifth incidence and third mortality worldwide. There were 951,000 new cases and about 723,000 patients died of it in 2012. Undoubtedly, gastric cancer has been affecting people's living standards, and is already a major public health problem in China with its population growth and ageing. Even though the detection methods and medical standards have improved, the five-year survival rate of people is still very low. While circular RNA (circRNA) is increasingly attracting attention from researchers, at the same time, its mystery has gradually been uncovered. Many studies have shown that circRNA can act as molecular sponge of miRNA to regulate gene expression and has an obviously different expression profile between cancerous and normal groups, which arouse people's curiosity and provide new opportunities for early detection of gastric cancer to improve the quality of life of patients. This study reviews current prevalence of gastric cancer in the word and China, as well as the characteristics and functions of circRNA and common laboratory detection methods involving circRNA in gastric cancer.

Effect of Drug Combination on Omeprazole Metabolism by Cytochrome P450 2C19 in Helicobacter pylori Eradication Therapy

Helicobacter pylori (H. pylori) infection is common and can result in gastric and duodenal ulcers, and in some cases, gastric lymphoma and cancer. Omeprazole (OMP)-in combination with clarithromycin (CLR), amoxicillin (AMX), tinidazole (TND), or metronidazole (MET)-is used in double or triple combination therapy for eradication of H. pylori. However, the roles of the drugs other than OMP are not clearly understood. Therefore, in the present study, we aimed to investigate any effects of these drugs on OMP metabolism by wild-type CYP2C19 using spectroscopy and enzyme kinetics. The dissociation constants (K_d) for CYP2C19 with OMP, CLR, AMX, TND, and MET were 8.6, 126, 156, 174, and 249 µM, respectively. The intrinsic clearance of OMP was determined to be 355 mL/min/µmol of CYP2C19. Metabolism of OMP was significantly inhibited by 69, 66, 28, and 40% in the presence of CLR, TND, AMX, and MET, respectively. Moreover, the combination of CLR and TND resulted in 76% inhibition of OMP metabolism, while the combination of AMX and MET resulted in 48% inhibition of OMP metabolism. Both combinations of drugs not only have antibacterial effects, but also enhance the effect of OMP by inhibiting its metabolism by CYP2C19. These results indicate that drug-drug interactions of co-administered drugs can cause complex effects, providing a basis for OMP dose adjustment when used in combination therapy for H. pylori eradication.

Crystal structure of CagV, the Helicobacter pylori homologue of the T4SS protein VirB8

The VirB/D type IV secretion system (T4SS) plays an essential role in materials transport between host cells and pathogenic Helicobacter pylori and is considered the major pathogenic mediator of H. pylori-associated gastric disease. VirB8, an inner membrane protein that interacts with many other proteins, is a crucial component for secretory function. Here, we present a crystal structure of the periplasmic domain of CagV, the VirB8 counterpart in the H. pylori Cag-T4SS. The structure reveals a fold similar to that of other VirB8 members except for the absence of the α5 helix, a discontinuous β1 strand, a larger angle between the α2 and α3 helices, a more hydrophobic surface groove, but exhibits a different dimer interface. Whether the dimerization occurs in solution was proved by mutagenesis, size-exclusion chromatography and cross-linking assays. Unlike the classical dimerization mode, the interface of the CagV dimer is principally formed by several hydrogen bonds, which indicates instability of dimerization. The structure here demonstrates the difference in dimerization among VirB8 homologues and indicates the considerable compositional and functional diversity of them in T4SS. DATABASE: Coordinates and structure factors have been deposited in the Protein Data Bank under accession codes 6IQT.

Sociodemographic and Lifestyle Factors in Relation to Gastric Cancer in a High-Risk Region of China: A Matched Case-Control Study

Objectives: To explore the role of sociodemographic and lifestyle factors in the development of gastric cancer in a high-risk region of China.Methods: In a case-control study, all newly diagnosed patients with gastric cancer were compared with healthy controls matched (1:1) by sex, age (±3 years), and place of residence during 2013-2017.Results: A total of 622 gastric cancer and 622 healthy controls were included. Larger household size (>4 family members) appeared to decrease gastric cancer risk for Helicobacter pylori-negative ones (odd ratio = 0.43, 95% CI = 0.26-0.70). Similarly, longer refrigerator ownership was associated with a 67% decreased risk in H. pylori-negative group (95% CI = 0.15-0.77). Participants with a family history of gastric cancer had nearly fivefold higher risk (odd ratio = 4.88, 95% CI = 2.49-9.55). Smoking attributed to 83% increased risk (odd ratio = 1.83, 95% CI = 1.19-2.80). Tea consumption dramatically decreased risk in whole study population (odd ratio = 0.28, 95% CI = 0.17-0.45).Conclusions: In summary, family history, smoking, H. pylori-related chronic atrophic gastritis, and H. pylori infection were positively associated with gastric cancer. Whereas, tea consumption and refrigerator use negatively associated with gastric cancer and could be promoted to reduce gastric cancer rate in high-risk populations, especially in the developing regions.

Systematic review with meta-analysis: association between Helicobacter pylori CagA seropositivity and odds of inflammatory bowel disease

BACKGROUND

Accumulating data support a protective role of Helicobacter pylori against inflammatory bowel diseases (IBD), which might be mediated by strain-specific constituents, specifically cagA expression.

AIM

To perform a systematic review and meta-analysis to more clearly define the association between CagA seropositivity and IBD.

METHODS

We identified comparative studies that included sufficient detail to determine the odds or risk of IBD, Crohn's disease (CD) or ulcerative colitis (UC) amongst individuals with vs without evidence of cagA expression (eg CagA seropositivity). Estimates were pooled using a random effects model.

RESULTS

Three clinical studies met inclusion criteria. cagA expression was represented by CagA seropositivity in all studies. Compared to CagA seronegativity overall, CagA seropositivity was associated with lower odds of IBD (OR 0.31, 95% CI 0.21-0.44) and CD (OR 0.25, 95% CI 0.17-0.38), and statistically nonsignificant lower odds for UC (OR 0.68, 95% CI 0.35-1.32). Similarly, compared to H pylori non-exposed individuals, H pylori exposed, CagA seropositive individuals had lower odds of IBD (OR 0.26, 95% CI 0.16-0.41) and CD (OR 0.23, 95% CI 0.15-0.35), but not UC (OR 0.66, 0.34-1.27). However, there was no significant difference in the odds of IBD, CD or UC between H pylori exposed, CagA seronegative and H pylori non-exposed individuals.

CONCLUSION

We found evidence for a significant association between CagA seropositive H pylori exposure and reduced odds of IBD, particularly CD, but not for CagA seronegative H pylori exposure. Additional studies are needed to confirm these findings and define underlying mechanisms.

Gastric cancer patients display a distinctive population of IFNg+IL10+ double positive CD8 T cells, which persists longer during prolonged activation

IL10 is generally regarded as a broad-spectrum regulatory cytokine. However, the role of IL10 in CD8 T cells remains controversial. In this study, we investigated the characteristics of endogenous IL10 by CD8 T cells in gastric cancer (GC) patients. Using intracellular staining, we found that in both GC patients and healthy controls, the majority of IL10-expressing CD8 T cells also presented concurrent IFNg expression. Interestingly, the frequency of IFNg⁺IL10⁺ CD8 T cells was significantly higher in GC patients than in healthy controls, while the frequency of IFNg⁺IL10^- CD8 T cells was significantly lower in GC patients than in healthy controls. Compared to the IFNg^-IL10^- CD8 T cells, both IFNg⁺IL10^- and IFNg⁺IL10⁺ CD8 T cells presented significantly higher expression of activation/inhibitory markers. Interestingly, the IFNg⁺IL10⁺ cells presented lower PD1 and TIM3 and higher KLRG1 than the IFNg⁺IL10^- CD8 T cells. Remarkably, the IFNg⁺IL10⁺ CD8 T cells, but not the IFNg⁺IL10^- CD8 T cells, were highly enriched in the CD45RO⁺CXCR5⁺ subset. Prolonged activation resulted in significant enrichment of IFNg⁺IL10⁺ CD8 T cells over time. Interestingly, compared to the CD45RO⁺CXCR5^- CD8 T cells, the CD45RO⁺CXCR5⁺ CD8 T cells presented stronger proliferation capacity at later stages of stimulation, and higher viability throughout the stimulation process. Overall, our investigation demonstrated that GC patients were enriched with a distinctive population of IFNg⁺IL10⁺ double positive CD8 T cells, which resembled T follicular cytotoxic cells and could persist longer during prolonged activation.

•

Gastric cancer patients presented an enrichment of IFNg⁺IL10⁺ CD8 T cells.

•

IFNg⁺IL10⁺ CD8 T cells showed unique patterns of PD1, KLRG1, and TIM3 expression.

•

IFNg⁺IL10⁺ CD8 T cells were enriched during prolonged stimulation.

•

CD45RO⁺CXCR5⁺ CD8 T cells presented better proliferation and lower death.

Identification and characterization of Helicobacter pylori O-acetylserine-dependent cystathionine β-synthase, a distinct member of the PLP-II family

O-acetylserine sulfhydrylase (OASS) and cystathionine β-synthase (CBS) are members of the PLP-II family, and involved in L-cysteine production. OASS produces L-cysteine via a de novo pathway while CBS participates in the reverse transsulfuration pathway. O-acetylserine-dependent CBS (OCBS) was previously identified as a new member of the PLP-II family, which are predominantly seen in bacteria. The bacterium Helicobacter pylori possess only one OASS (hp0107) gene and we showed that the protein coded by this gene actually functions as an OCBS and utilizes L-homocysteine and O-acetylserine (OAS) to produce cystathionine. HpOCBS did not show CBS activity with the substrate L-serine and required OAS exclusively. The HpOCBS structure in complex with methionine showed a closed cleft state, explaining the initial mode of substrate binding. Sequence and structural analyses showed differences between the active sites of OCBS and CBS, and explain their different substrate preferences. We identified three hydrophobic residues near the active site of OCBS, corresponding to one serine and two tyrosine residues in CBSs. Mutational studies were performed on HpOCBS and Saccharomyces cerevisiae CBS. A ScCBS double mutant (Y158F/Y226V) did not display activity with L-serine, indicating indispensability of these polar residues for selecting substrate L-serine, however, did show activity with OAS.

Extraction of molecular features for the drug discovery targeting protein-protein interaction of Helicobacter pylori CagA and tumor suppressor protein ASSP2

Half of the world population is infected by the Gram-negative bacterium Helicobacter pylori (H. pylori). It colonizes in the stomach and is associated with severe gastric pathologies including gastric cancer and peptic ulceration. The most virulent factor of H. pylori is the cytotoxin-associated gene A (CagA) that is injected into the host cell. CagA interacts with several host proteins and alters their function, thereby causing several diseases. The most well-known target of CagA is the tumor suppressor protein ASPP2. The subdomain I at the N-terminus of CagA interacts with the proline-rich motif of ASPP2. Here, in this study, we carried out alanine scanning mutagenesis and an extensive molecular dynamics simulation summing up to 3.8 μs to find out hot spot residues and discovered some new protein-protein interaction (PPI)-modulating molecules. Our findings are in line with previous biochemical studies and further suggested new residues that are crucial for binding. The alanine scanning showed that mutation of Y207 and T211 residues to alanine decreased the binding affinity. Likewise, dynamics simulation and molecular mechanics with generalized Born surface area (MMGBSA) analysis also showed the importance of these two residues at the interface. A four-feature pharmacophore model was developed based on these two residues, and top 10 molecules were filtered from ZINC, NCI, and ChEMBL databases. The good binding affinity of the CHEMBL17319 and CHEMBL1183979 molecules shows the reliability of our adopted protocol for binding hot spot residues. We believe that our study provides a new insight for using CagA as the therapeutic target for gastric cancer treatment and provides a platform for a future experimental study.

A transcriptional signature associated with non-Hodgkin lymphoma in the blood of patients with Q fever

Coxiella burnetii, the agent causing Q fever, has been associated with B-cell non-Hodgkin lymphoma (NHL). To better clarify this link, we analysed the genetic transcriptomic profile of peripheral blood leukocytes from patients with C. burnetii infection to identify possible links to lymphoma. Microarray analyses revealed that 1189 genes were expressed differently (p <.001 and fold change ≥4) in whole blood of patients with C. burnetii infection compared to controls. In addition, 95 genes expressed in patients with non-Hodgkin lymphoma (NHL) and in patients with C. burnetii persistent infection have allowed us to establish the 'C. burnetii-associated NHL signature'. Among these, 33 genes previously found modulated in C. burnetii-associated -NHL by the microarray analysis were selected and their mRNA expression levels were measured in distinct C. burnetii-induced pathologies, namely, acute Q fever, focalized persistent infection, lymphadenitis and C.burnetii-associated NHL. Specific genes involved in anti-apoptotic process were found highly expressed in leukocytes from patients with C. burnetii associated-NHL: MIR17HG, REL and SP100. This signature differed from that found for NHL-control group. Patients with C. burnetii lymphadenitis presented significant elevated levels of BCL2 and ETS1 mRNAs. Altogether, we identified a specific transcriptionnal signature for NHL during C. burnetii infection reflecting the up-regulation of anti-apoptotic processes and the fact that lymphadenitis might constitute a critical step towards lymphomagenesis.

Changes of tight junction and interleukin-8 expression using a human gastroid monolayer model of Helicobacter pylori infection

BACKGROUND

Lack of a model that mirrors Helicobacter pylori-induced gastric mucosal inflammation has hampered investigation of early host-bacterial interactions. We used an ex vivo model of human stomach, gastric epithelial organoid monolayers (gastroid monolayers) to investigate interactions of H pylori infection and the apical junctional complex and interleukin-8 (IL-8) expression.

METHOD

Morphology of human antral mucosal gastroid monolayers was evaluated using histology, immunohistochemical (IHC) staining, and transmission electron microscopy (TEM). Functional and gross changes in the apical junctional complexes were assessed using transepithelial electrical resistance (TEER), cytotoxicity assays, and confocal laser scanning microscopy. IL-8 expression was evaluated by real-time quantitative PCR and ELISA.

RESULTS

When evaluated by IHC and TEM, the morphology of gastroid monolayers closely resembled in vivo human stomach. Following inoculation of H pylori, TEER transiently declined (up to 51%) in an H pylori density-dependent manner. TEER recovered by 48 hours post-infection and remained normal despite continued presence and replication of H pylori. Confocal scanning microscopy showed minimal disruption of zonula occludens-1 or E-cadherin structure. IL-8 production was unchanged by infection with either CagA-positive or CagA-negative H pylori and JNK and MEK inhibitors did not suppress IL-8 production, whereas p38 and IKK inhibitor significantly did.

CONCLUSION

Human gastroid monolayers provide a model for experimental H pylori infection more consistent with in vivo human infections than seen with typical gastric epithelial cell lines. This ex vivo system should lead to better understanding of H pylori host-pathogen interactions.

Helicobacter pylori urease induces pro-inflammatory effects and differentiation of human endothelial cells: Cellular and molecular mechanism

BACKGROUND

Helicobacter pylori urease (HPU) is a key virulence factor that enables bacteria to colonize and survive in the stomach. We early demonstrated that HPU, independent of its catalytic activity, induced inflammatory and angiogenic responses in vivo and directly activated human neutrophils to produce reactive oxygen species (ROS). We have investigated the effects of HPU on endothelial cells, focusing on the signaling mechanism involved.

METHODS

Monolayers of human microvascular endothelial cells (HMEC-1) were stimulated with HPU (up to 10 nmol/L): Paracellular permeability was accessed through dextran-FITC passage. NO and ROS production was evaluated using intracellular probes. Proteins or mRNA expressions were detected by Western blotting and fluorescence microscopy or qPCR assays, respectively.

RESULTS

Treatment with HPU enhanced paracellular permeability of HMEC-1, preceded by VE-cadherin phosphorylation and its dissociation from cell-cell junctions. This caused profound alterations in actin cytoskeleton dynamics and focal adhesion kinase (FAK) phosphorylation. HPU triggered ROS and nitric oxide (NO) production by endothelial cells. Increased intracellular ROS resulted in nuclear factor kappa B (NF-κB) activation and upregulated expression of cyclooxygenase-2 (COX-2), hemeoxygenase-1 (HO-1), interleukin-1β (IL-1β), and intercellular adhesion molecule-1 (ICAM-1). Higher ICAM-1 and E-selectin expression was associated with increased neutrophil adhesion on HPU-stimulated HMEC monolayers. The effects of HPU on endothelial cells were dependent on ROS production and lipoxygenase pathway activation, being inhibited by esculetin. Additionally, HPU improved vascular endothelial growth factor receptor 2 (VEGFR-2) expression.

CONCLUSION

The data suggest that the pro-inflammatory properties of HPU drive endothelial cell to a ROS-dependent program of differentiation that contributes to the progression of H pylori infection.

Biologic roles of the ABH and Lewis histo-blood group antigens Part I: infection and immunity

The ABH and Lewis antigens were among the first of the human red blood cell polymorphisms to be identified and, in the case of the former, play a dominant role in transfusion and transplantation. But these two therapies are largely twentieth century innovations, and the ABH and related carbohydrate antigens are not only expressed on a very wide range of human tissues, but were present in primates long before modern humans evolved. Although we have learned a great deal about the biochemistry and genetics of these structures, the biological roles that they play in human health and disease are incompletely understood. This review and its companion, to appear in a later issue of Vox Sanguinis, will focus on a few of the biologic and pathologic processes which appear to be affected by histo-blood group phenotype. The first of the two reviews will explore the interactions of two bacteria with the ABH and Lewis glycoconjugates of their human host cells, and describe the possible connections between the immune response of the human host to infection and the development of the AB-isoagglutinins. The second review will describe the relationship between ABO phenotype and thromboembolic disease, cardio-vascular disease states, and general metabolism.

Association between rs20417 polymorphism in cyclooxygenase-2 and gastric cancer susceptibility: Evidence from15 case-control studies

OBJECTIVE

Previous studies have reported an association between cyclooxygenase-2 (COX-2) polymorphism and gastric cancer (GC) susceptibility, but their results are controversial. This meta-analysis was intended to evaluate the relationship between the COX-2 rs20417 polymorphism and GC susceptibility in different ethnic groups.

METHODS

We searched PubMed, EMBASE, Web of Knowledge, and the Chinese Biomedical Database (CBM) for relevant case-control studies published up to October 6, 2018, which reported an association between the COX-2 rs20417 polymorphism and gastric cancer risk. Odds ratios (ORs) with 95% confidence intervals (CIs) were used to assess the strength of this association.

RESULTS

15 papers detailing case-control studies were included in the analysis, which included a total of 2848 GC cases and 4962 healthy controls. The meta-analysis results indicated that the COX-2 rs20417 polymorphism was associated with increased GC susceptibility under allele (G vs C: OR = 1.67, 95%CI = 1.19-2.35, P = .003), heterozygous (GG vs CG: OR = 1.44, 95%CI = 1.03-2.02, P = .034), dominant (GC+CC vs GG: OR = 1.66, 95%CI = 1.18-2.34, P = .004), homozygous (GG vs CC:OR = 2.20, 95%CI = 1.07-4.54, P = .033), and recessive models (CC vs GG+CG:OR = 2.05, 95%CI = 1.09-3.85, P = .025). An analysis of ethnic subgroups revealed that the COX-2 rs20417 polymorphism was significantly associated with GC susceptibility in Asians under all 5 models (G vs C: OR = 2.22, 95%CI = 1.66-2.96, P < .001; GG vs CC: OR = 4.29, 95%CI = 1.94-9.50, P < .001; GG vs CG: OR = 1.86, 95%CI = 1.34-2.58, P < .001; CC vs GG+CG: OR = 3.73, 95%CI = 1.92-7.24, P < .001; GC+CC vs GG: OR = 2.20, 95%CI = 1.65-2.93, P < .001). Helicobacter pylori positive patients suffered a high risk of GC, compared to H pylori negative patients under the dominant model (OR = 3.09, 95%CI = 1.80-5.32, P < .001).

CONCLUSION

This meta-analysis of 15 case-control studies provides strong evidence that the COX-2 rs20417 polymorphism increases the risk of GC susceptibility in general populations, especially in Asians. Helicobacter pylori positive patients and those with the COX-2 rs20417 polymorphism had a higher risk of developing GC.

The prognostic role of Helicobacter pylori in gastric cancer patients: A meta-analysis

BACKGROUND

The prognostic value of Helicobacter pylori (H. pylori) infection in gastric cancer patients has been investigated over many years; however, the results remain inconclusive. Thus, we performed a comprehensive review of currently available evidence via a systemic meta-analysis to evaluate the effects of H. pylori infection on the prognosis of gastric cancer patients.

METHODS

Studies that evaluated the prognostic value of H. pylori infection in gastric cancer were extracted in March 2016 by searching PubMed, EMBASE, and the Cochrane Central Register of Controlled Trials. We obtained or calculated hazard ratios (HRs) and the associated 95% confidence intervals (CIs) from the identified studies, and conducted random-effects model analyses of overall survival and progression-free survival. Twenty-four studies with a cumulative sample size of 7191 patients were included in our analysis.

RESULTS

Our meta-analysis revealed that H. pylori infection is an indicator of improved overall survival in gastric cancer patients (HR, 0.79; 95% CI, 0.64-0.99); however, this was only true for European patients. The benefits of H. pylori infection were not detected in Asian gastric cancer patients (HR, 1.01; 95% CI, 0.91-1.12) or those in the United States (HR, 0.88; 95% CI, 0.73-1.05). Subgroup analyses revealed that the prognostic significance of H. pylori infection differed with respect to the year of study publication, number of patients, H. pylori detection method, tumor stage, H. pylori-positive rate, and risk of bias. The prognostic value of H. pylori infection on progression-free survival was unclear (HR, 0.84; 95% CI, 0.70-1.01).

CONCLUSIONS

These data provide limited, moderate-quality evidence that H. pylori infection is an indicator of good prognosis in European gastric cancer patients. However, this is not necessarily true for other populations.

Helicobacter pylori infection alters gastric and tongue coating microbial communities

OBJECTIVE

Infection with Helicobacter pylori (H pylori), especially cytotoxin-associated gene A-positive (CagA+) strains, has been associated with various gastrointestinal and extragastric diseases. The aim of this study was to characterize H pylori-induced alterations in the gastric and tongue coating microbiota and evaluate their potential impacts on human health.

DESIGN

The gastric mucosa and tongue coating specimens were collected from 80 patients with chronic gastritis, and microbiota profiles were generated by 16S rRNA gene sequencing. Samples were grouped as H pylori negative (n = 32), CagA-negative H pylori infection (n = 13), and CagA-positive H pylori infection (n=35). The comparison of bacterial relative abundance was made using a generalized linear model. Functional profiling of microbial communities was predicted with PICRUSt and BugBase. Microbial correlation networks were produced by utilizing SparCC method.

RESULTS

Significant alterations of the gastric microbiota were found in the H pylori+/CagA+ samples, represented by a decrease in bacterial diversity, a reduced abundance of Roseburia, and increased abundances of Helicobacter and Haemophilus genera. At the community level, functions involved in biofilm forming, mobile element content, and facultative anaerobiosis were significantly decreased in gastric microbiome of the H pylori+ subjects. The presence of CagA gene was linked to an increased proportion of Gram-negative bacteria in the stomach, thereby contributing to an upregulation of lipopolysaccharide (LPS) biosynthesis. The number of bacterial interactions was greatly reduced in networks of both tongue coating and gastric microbiota of the H pylori+/CagA+ subject, and the cooperative bacterial interactions dominated the tongue coating microbiome.

CONCLUSIONS

Infection with H pylori strains possessing CagA may increase the risk of various diseases, by upregulating LPS biosynthesis in the stomach and weakening the defense of oral microbiota against microorganisms with pathogenic potential.

Risk Factors of Gastric Cancer in High-Risk Region of China: A Population-Based Case-control Study

Background: The reason for the high incidence of gastric cancer (GC) in Xianyou County of China was largely unknown. We aimed to explore the potential sociodemographic risk factors and their associations to GC. Methods: A population-based case-control study was conducted during March 2013 and April 2016 in Xianyou County. All newly diagnosed patients of GC were recruited as cases, while controls were selected by matching for cases’ sex, age (± 3 years) and the place of residence. Results: A total of 523 GC cases and 523 matched healthy controls were included in the final analysis with mean age of 66.27±8.81 years for cases and 66.31±8.83 years for controls, respectively. Participants with low socioeconomic status were observed with higher GC risk compared to those in high socioeconomic status (adjusted OR=2.10, 95% CI: 1.13-3.89). Compared to those regularly drink green tea, patients did not have this dietary habit had nearly 3-fold increased GC risk (adjusted OR=2.91, 95% CI: 1.38-6.13). Other dietary habit, including consumption of hard food, omission of breakfast, consumption of pickled vegetables 30 years ago, overeating were all associated with increased risk of GC. Interaction effect were found. Patients in low socioeconomic status and skipped breakfast had 10-fold higher risk of GC compared to reference group in high socioeconomic status and eat breakfast regularly (OR=10.71, 95% CI: 5.19-22.10). Furthermore, patients in low socioeconomic status and consumed pickled vegetable 30 years ago had 6-fold higher risk of GC compared to those in high socioeconomic status but did not intake pickled vegetables 30 years ago (OR=6.11, 95% CI: 3.87-9.66). Conclusion: High incidence of GC risk in Xianyou County might be partly attributed to various sociodemographic factors. Specific prevention effort could be target on population in low socioeconomic status combined with habit of breakfast omission or intake of pickled vegetables.

Intracellular Degradation of Helicobacter pylori VacA Toxin as a Determinant of Gastric Epithelial Cell Viability

Helicobacter pylori VacA is a secreted pore-forming toxin that induces cell vacuolation in vitro and contributes to the pathogenesis of gastric cancer and peptic ulcer disease. We observed that purified VacA has relatively little effect on the viability of AGS gastric epithelial cells, but the presence of exogenous weak bases such as ammonium chloride (NH₄Cl) enhances the susceptibility of these cells to VacA-induced vacuolation and cell death. Therefore, we tested the hypothesis that NH₄Cl augments VacA toxicity by altering the intracellular trafficking of VacA or inhibiting intracellular VacA degradation. We observed VacA colocalization with LAMP1- and LC3-positive vesicles in both the presence and absence of NH₄Cl, indicating that NH₄Cl does not alter VacA trafficking to lysosomes or autophagosomes. Conversely, we found that supplemental NH₄Cl significantly increases the intracellular stability of VacA. By conducting experiments using chemical inhibitors, stable ATG5 knockdown cell lines, and ATG16L1 knockout cells (generated using CRISPR/Cas9), we show that VacA degradation is independent of autophagy and proteasome activity but dependent on lysosomal acidification. We conclude that weak bases like ammonia, potentially generated during H. pylori infection by urease and other enzymes, enhance VacA toxicity by inhibiting toxin degradation.

Characterization of gastric cells infection by diverse Helicobacter pylori strains through Fourier-transform infrared spectroscopy

The infection of Helicobacter pylori, covering 50% of the world-population, leads to diverse gastric diseases as ulcers and cancer along the life-time of the human host. To promote the discovery of biomarkers of bacterial infection, in the present work, Fourier-transform infrared spectra were acquired from adenocarcinoma gastric cells, incubated with H. pylori strains presenting different genotypes concerning the virulent factors cytotoxin associated gene A and vacuolating cytotoxin A. Defined absorbance ratios were evaluated by diverse methods of statistical inference, according to the fulfillment of the tests assumptions. It was possible to define from the gastric cells, diverse absorbance ratios enabling to discriminate: i) The infection; ii) the bacteria genotype; and iii) the gastric disease of the patients from which the bacteria were isolated. These biomarkers could fasten the knowledge of the complex infection process while promoting a platform for a new diagnostic method, rapid but also specific and sensitive towards the diagnosis of both infection and bacterial virulence.

Protein changes in gastric epithelial cells RGM-1 in response to Helicobacter pylori infection

Helicobacter pylori-induced inflammation significantly increases the risk of gastric cancer. To investigate the role of H. pylori infection in gastric epithelial cell carcinogenesis, flow cytometry was used to analyze the apoptosis of gastric epithelial cells infected by H. pylori. Next, LTQ MS mass spectrometry (MS) was applied to identify protein changes in gastric epithelial cells infected with H. pylori, and then bioinformatics was adopted to analyze the cellular localization and biological function of differential proteins. LTQ MS/MS successfully identified identified 22 differential proteins successfully, including 20 host-cell proteins and two H. pylori bacterial proteins. Also, human proteins were located in all areas of cells and involved in various cell biological functions. The oncogene proteins p53, p16, and C-erbB-2 proteins in H. pylori-infected RGM-1 cells were remarkably increased from the analysis by Western blot analysis. H. pylori infection of gastric epithelial cells leads to changes in various protein components in the cell, and enhances the expression of oncogene proteins, thereby increasing the possibility of possibility of carcinogenesis of H. pylori infection.