Helicobacter pylori Virulence Factors Exploiting Gastric Colonization and its Pathogenicity

Helicobacter pylori East Asian type CagA hijacks more SHIP2 by its EPIYA-D motif to potentiate the oncogenicity

CagA is a significant oncogenic factor injected into host cells by Helicobacter pylori, which is divided into two subtypes: East Asian type (CagAE), characterized by the EPIYA-D motif, and western type (CagAW), harboring the EPIYA-C motif. CagAE has been reported to have higher carcinogenicity than CagAW, although the underlying reason is not fully understood. SHIP2 is an intracellular phosphatase that can be recruited by CagA to perturb the homeostasis of intracellular signaling pathways. In this study, we found that SHIP2 contributes to the higher oncogenicity of CagAE. Co-Immunoprecipitation and Pull-down assays showed that CagAE bind more SHIP2 than CagAW. Immunofluorescence staining showed that a higher amount of SHIP2 recruited by CagAE to the plasma membrane catalyzes the conversion of PI(3,4,5)P3 into PI(3,4)P2. This alteration causes higher activation of Akt signaling, which results in enhanced IL-8 secretion, migration, and invasion of the infected cells. SPR analysis showed that this stronger interaction between CagAE and SHIP2 stems from the higher affinity between the EPIYA-D motif of CagAE and the SH2 domain of SHIP2. Structural analysis revealed the crucial role of the Phe residue at the Y + 5 position in EPIYA-D. After mutating Phe of CagAE into Asp (the corresponding residue in the EPIYA-C motif) or Ala, the activation of downstream Akt signaling was reduced and the malignant transformation of infected cells was alleviated. These findings revealed that CagAE hijacks SHIP2 through its EPIYA-D motif to enhance its carcinogenicity, which provides a better understanding of the higher oncogenic risk of H. pylori CagAE.

Cleavage of cell junction proteins as a host invasion strategy in leptospirosis

Infection and invasion are the prerequisites for developing the disease symptoms in a host. While the probable mechanism of host invasion and pathogenesis is known in many pathogens, very little information is available on Leptospira invasion/pathogenesis. For causing systemic infection Leptospira must transmigrate across epithelial barriers, which is the most critical and challenging step. Extracellular and membrane-bound proteases play a crucial role in the invasion process. An extensive search for the proteins experimentally proven to be involved in the invasion process through cell junction cleavage in other pathogens has resulted in identifying 26 proteins. The similarity searches on the Leptospira genome for counterparts of these 26 pathogenesis-related proteins identified at least 12 probable coding sequences. The proteins were either extracellular or membrane-bound with a proteolytic domain to cleave the cell junction proteins. This review will emphasize our current understanding of the pathogenic aspects of host cell junction-pathogenic protein interactions involved in the invasion process. Further, potential candidate proteins with cell junction cleavage properties that may be exploited in the diagnostic/therapeutic aspects of leptospirosis will also be discussed. KEY POINTS: • The review focussed on the cell junction cleavage proteins in bacterial pathogenesis • Cell junction disruptors from Leptospira genome are identified using bioinformatics • The review provides insights into the therapeutic/diagnostic interventions possible.

Phellodendron chinense C.K.Schneid: An in vitro study on its anti-Helicobacter pylori effect

ETHNOPHARMACOLOGICAL RELEVANCE

Phellodendron chinense C.K.Schneid(P. chinense Schneid) is known in TCM as Huang Bo, is traditionally used to support gastrointestinal function and alleviate stomach-related ailments, including gastric ulcer bleeding and symptoms of gastroesophageal reflux disease. Helicobacter pylori (H. pylori) is classified by the WHO as a Group 1 carcinogen. However, the specific activity and mechanism of action of P. chinense Schneid against H. pylori infection remain unclear. It has been noted that Huangjiu processing may alter the bitter and cold properties of P. chinense Schneid, but its effect on antimicrobial activity requires further investigation. Additionally, it remains uncertain whether berberine is the sole antimicrobial active component of P. chinense Schneid.

AIM OF STUDY

This study aims to elucidate the anti-H. pylori infection activity of P. chinense Schneid, along with its mechanism of action and key antimicrobial active components.

MATERIALS AND METHODS

Phytochemical analysis was carried out by UPLC-MS/MS. HPLC was employed to quantify the berberine content of the extracts. Antimicrobial activity was assessed using the micro broth dilution method. Morphology was observed using SEM. The impact on urease activity was analyzed through in vitro urease enzyme kinetics. RT-qPCR was employed to detect the expression of virulence genes, including adhesin, flagellum, urease, and cytotoxin-related genes. The adhesion effect was evaluated by immunofluorescence staining and agar culture.

RESULTS

P. chinense Schneid exhibited strong antimicrobial activity against both antibiotic-sensitive and resistant H. pylori strains, with MIC ranging from 40 to 160 μg/mL. Combination with amoxicillin, metronidazole, levofloxacin, and clarithromycin did not result in antagonistic effects. P. chinense Schneid induced alterations in bacterial morphology and structure, downregulated the expression of various virulence genes, and inhibited urease enzyme activity. In co-infection systems, P. chinense Schneid significantly attenuated H. pylori adhesion and urease relative content, thereby mitigating cellular damage caused by infection. Huangjiu processing enhanced the anti-H. pylori activity of P. chinense Schneid. Besides berberine, P. chinense Schneid contained seven other components with anti-H. pylori activity, with palmatine exhibiting the strongest activity, followed by jatrorrhizine.

CONCLUSIONS

This study sheds light on the potential therapeutic mechanisms of P. chinense Schneid against H. pylori infection, demonstrating its capacity to disrupt bacterial structure, inhibit urease activity, suppress virulence gene transcription, inhibit adhesion, and protect host cells. The anti-H. pylori activity of P. chinense Schneid was potentiated by Huangjiu processing, and additional components beyond berberine were identified as possessing strong anti-H. pylori activity. Notably, jatrorrhizine, a core component of P. chinense Schneid, exhibited significant anti-H. pylori activity, marking a groundbreaking discovery.

Antitumor Effects of Resveratrol Opposing Mechanisms of Helicobacter pylori in Gastric Cancer

Gastric cancer is an aggressive and multifactorial disease. Helicobacter pylori (H. pylori) is identified as a significant etiological factor in gastric cancer. Although only a fraction of patients infected with H. pylori progresses to gastric cancer, bacterial infection is critical in the pathology and development of this malignancy. The pathogenic mechanisms of this bacterium involve the disruption of the gastric epithelial barrier and the induction of chronic inflammation, oxidative stress, angiogenesis and metastasis. Adherence molecules, virulence (CagA and VacA) and colonization (urease) factors are important in its pathogenicity. On the other hand, resveratrol is a natural polyphenol with anti-inflammatory and antioxidant properties. Resveratrol also inhibits cancer cell proliferation and angiogenesis, suggesting a role as a potential therapeutic agent against cancer. This review explores resveratrol as an alternative cancer treatment, particularly against H. pylori-induced gastric cancer, due to its ability to mitigate the pathogenic effects induced by bacterial infection. Resveratrol has shown efficacy in reducing the proliferation of gastric cancer cells in vitro and in vivo. Moreover, the synergistic effects of resveratrol with chemotherapy and radiotherapy underline its therapeutic potential. However, further research is needed to fully describe its efficacy and safety in treating gastric cancer.

The Efficacy and Safety of Minocycline-Containing Quadruple Therapies Against Helicobacter pylori Infection: A Retrospective Cohort Study

Background

Minocycline, a derivative of tetracycline, has anti-Helicobacter pylori (H. pylori) properties and can be used to treat H. pylori infection. However, only a few randomized controlled trials (RCTs) have investigated the efficacy of minocycline-containing quadruple therapy (MCQT) in treating H. pylori infection. This study aimed to determine the efficacy and safety of MCQT and investigate the factors influencing both aspects.

Methods

This was a retrospective cohort study. Patients diagnosed with H. pylori infection between January 1, 2022, and July 31, 2023 at. The primary outcome was the eradication rate of H. pylori, and the secondary outcome was the number and type of adverse events.

Results

A total of 828 patients were included in this study. The overall H. pylori eradication rate among the included patients at 95% confidence interval (CI) (Range 0.864 to 0.907) was 88.53%. The H. pylori eradication rate for patients who received MCQT regimen as the primary therapy was 92.28% (95% CI: 0.901-0.945), significantly higher than that of patients who received MCQT as rescue therapy (80.81%; 95% CI: 0.761-0.855, P=0.003). Adverse events, including dizziness, abdominal distension, diarrhea, nausea, abdominal discomfort, constipation, headache, rash, sleep disorder, palpitation, backache, and anorexia, occurred in 185 (22.34%) patients, with dizziness being the most common (75/828, 9.06%). Compliance with MCQT therapy was an independent factor influencing H. pylori eradication in patients receiving MCQT as a primary therapy. Compliance and presence or absence of H. pylori infection symptoms at the time of screening were independent factors influencing H. Pylori eradication in patients receiving MCQT as rescue therapy. Factors that influenced the occurrence of adverse events included reasons for H. pylori infection screening, residence, treatment compliance, and the use of acid-suppressant regimens.

Conclusion

MCQT regimens were effective in H. pylori infection eradication, and the treatment resulted only in fewer adverse events when used as primary or rescue therapies for H. pylori infection treatment. Future prospective studies with larger sample sizes and more comprehensive data are needed to validate our findings.

Lyophilized cell-free supernatants of Limosilactobacillus fermentum T0701 exhibited antibacterial activity against Helicobacter pylori

Helicobacter pylori is a prominent gastrointestinal pathogen associated with various gastrointestinal illnesses. It presents substantial health risks due to its antibiotic resistance. Therefore, it is crucial to identify alternative treatments for H. pylori infections. Limosilactobacillus spp exhibit probiotic properties with beneficial effects in humans; however, the mechanisms by which it counteracts H. pylori infection are unknown. This study aimed to evaluate the potential of Limosilactobacillus fermentum T0701 lyophilized cell-free supernatants (LCFS) against H. pylori. The LCFS has varying antimicrobial activities, with inhibition zones of up to 10.67 mm. The minimum inhibitory concentration and minimum bacterial concentration of LCFS are 6.25-25.00 mg/mL and 6.25 mg/mL to > 50.00 mg/mL, respectively, indicating its capability to inhibit H. pylori. There is morphological damage observed in H. pylori treated with LCFS. Additionally, H. pylori adhesion to AGS cells (human gastric adenocarcinoma epithelial cells) reduces by 74.23%, highlighting the LCFS role in preventing bacterial colonization. Moreover, LCFS exhibits no cytotoxicity or morphological changes in AGS cells, and with no detected virulence or antimicrobial resistance genes, further supporting its safety profile. L. fermentum T0701 LCFS shows promise as a safe and effective non-toxic agent against H. pylori, with the potential to prevent gastric colonization.

Potential therapeutic targets of gastric cancer explored under endogenous network modeling of clinical data

Improvement in the survival rate of gastric cancer, a prevalent global malignancy and the leading cause of cancer-related mortality calls for more avenues in molecular therapy. This work aims to comprehend drug resistance and explore multiple-drug combinations for enhanced therapeutic treatment. An endogenous network modeling clinic data with core gastric cancer molecules, functional modules, and pathways is constructed, which is then transformed into dynamics equations for in-silicon studies. Principal component analysis, hierarchical clustering, and K-means clustering are utilized to map the attractor domains of the stochastic model to the normal and pathological phenotypes identified from the clinical data. The analyses demonstrate gastric cancer as a cluster of stable states emerging within the stochastic dynamics and elucidate the cause of resistance to anti-VEGF monotherapy in cancer treatment as the limitation of the single pathway in preventing cancer progression. The feasibility of multiple objectives of therapy targeting specified molecules and/or pathways is explored. This study verifies the rationality of the platform of endogenous network modeling, which contributes to the development of cross-functional multi-target combinations in clinical trials.

Revolution of Helicobacter pylori treatment

Helicobacter pylori infection is a major global health concern, and its management has witnessed a revolutionary shift with the emergence of antibiotic resistance. In this review, I explore the mechanisms of H. pylori antibiotic resistance and highlight the critical need for susceptibility-based eradication treatments. The increasing prevalence of antibiotic-resistant strains requires innovative approaches to combat this resilient pathogen. I also delve into the importance of mass screening as a preventive strategy for early detection and intervention, describing my experience in Bhutan. Additionally, I explore promising alternatives, such as vaccination. The aim of this review is to provide insight into the evolving landscape of H. pylori treatment and highlight the need for a paradigm shift in the approach to combating this persistent bacterial infection.

Carbonic anhydrase and bacterial metabolism: a chance for antibacterial drug discovery

INTRODUCTION

Carbonic anhydrases (CAs, EC 4.2.1.1) play a pivotal role in the regulation of carbon dioxide , bicarbonate, and hydrogen ions within bacterial cells, ensuring pH homeostasis and facilitating energy production. We conducted a systematic literature search (PubMed, Web of Science, and Google Scholar) to examine the intricate interplay between CAs and bacterial metabolism, revealing the potential of CA inhibitors (CAIs) as innovative therapeutic agents against pathogenic bacteria.

AREA COVERED

Inhibition of bacterial CAs was explored in various pathogens, emphasizing the CA roles in microbial virulence, survival, and adaptability. Escherichia coli, a valid and convenient model microorganism, was recently used to investigate the effects of acetazolamide (AAZ) on the bacterial life cycle. Furthermore, the effectiveness of CAIs against pathogenic bacteria has been further substantiated for Vancomycin-Resistant Enterococci (VRE) and antibiotic-resistant Neisseria gonorrhoeae strains.

EXPERT OPINION

CAIs target bacterial metabolic pathways, offering alternatives to conventional therapies. They hold promise against drug-resistant microorganisms such as VRE and N. gonorrhoeae strains. CAIs offer promising avenues for addressing antibiotic resistance and underscore their potential as novel antibacterial agents. Recognizing the central role of CAs in bacterial growth and pathogenicity will pave the way for innovative infection control and treatment strategies possibly also for other antibiotic resistant species.

Prevalence of cagA, cagM, vacA and oipA genes in isolates of Helicobacter pylori obtained from hospital patients in Northeast Brazil

Helicobacter pylori is a major cause of gastrointestinal disorders such as chronic gastritis, peptic ulcers, mucosa-associated lymphoid tissue (MALT) lymphoma, and gastric cancer. It is estimated that around half of the world's population is infected with this pathogen, with underdeveloped countries reporting the highest frequencies. The genes cagA, cagM, vacA, and oipA are some of the most important virulence factors of H. pylori; however, there are no recent studies from Recife-PE demonstrating their frequency, and their relationship with severe gastric modifications. This work aims to use qualitative PCR to detect the virulence genes cagA, cagM, vacA, and oipA in H. pylori isolates obtained from patients in a public hospital in Recife (PE). We collected samples from the stomach's body and antrum of 147 patients, from which 71 (48%) tested positive for H. pylori. Among positive samples, the most frequently infected gender was female (44/71, 62%), and the most frequently infected age group was those above the age of 46 (31/71, 44%). Histological examination of H. pylori-positive samples revealed alterations other than chronic gastritis, including metaplasia and atrophy. The frequency of cagA, cagM, and oipA genes were identified in 84%, 56%, and 69% of the samples tested, respectively, as well as the vacA-s1m1 allelic combination (77%). However, there was no statistically significant variation in the occurrence of these genes, therefore they cannot be considered unique markers of severity in our setting. New research with larger samples and investigations of other genetic markers can aid uncover local risk factors and lead to a better understanding of H. pylori's pathogenesis.

Detection of Helicobacter pylori strain types and analysis of risk factors among subjects from Hainan Province, China

OBJECTIVE

To explore the prevalence of type I and type II Helicobacter pylori infection and investigate risk factors in a population from Hainan Province in China.

METHODS

Data came from a large, cross-sectional study conducted from August 2022 to April 2023 involving five cities of Hainan. Subjects with confirmed 14C-urea breath test (UBT) and positive serological assay were included. All subjects had a gastroscopy. According to presence or absence of CagA/VacA proteins, subjects were classified as either type I (present) or type II strains (absent). Gastroscopic findings and several socio-demographic factors were examined for correlation with antibody serotyping.

RESULTS

In total, 410 subjects were investigated for H. pylori strain types. The overall prevalence of the highly virulent, type I H. pylori strain was 79% (324/410) and type II strain was 21% (86/410). There was a strong association between type I strain and peptic ulcer disease. Of several sociodemographic factors investigated, only smoking and data over baseline (DOB) values showed significant differences between type 1 and type II strains. Logistic regression analysis showed a lower risk of type I H. pylori infection in smokers compared with non-smokers, and a higher risk of H. pylori type I infection in subjects with medium and high data over baseline (DOB) values compared with subjects who had low DOB values.

CONCLUSION

Highly virulent, type I H. pylori infections predominate in Hainan and the co-positivity of CagA and VacA antibodies are related to type I H. pylori infection. We found that Type I H. pylori was closely associated with peptic ulcer disease and the DOB values were generally high.

Effect of concurrent infection of Helicobacter pylori with Toxoplasma gondii infection on gastric pathology

BACKGROUND

Toxoplasma gondii (T. gondii) and Helicobacter pylori (H. pylori) are among the most prevalent foodborne parasitic and bacterial infections worldwide. However, the concurrent impact of coinfection on gastric pathology has yet to be studied in depth. The effect of coinfection generally either adds a synergetic or antagonistic impact; we aimed in the current work to assess the impact of T. gondii coinfection on the progression of H. pylori-associated gastric pathology and reporting H. pylori virulent strains. The study was conducted on 82 patients complaining of persistent gastrointestinal symptoms with failed treatment response and prone to endoscopy. They were subjected to stool examination to detect H. pylori antigen, serological screening for latent toxoplasmosis, endoscopy, histopathological examination, and molecular detection of H. pylori virulence strains in gastric biopsies. Out of the 82 patients, 62 patients were positive for H. pylori antigen in stool and 55 patients confirmed positivity by histopathology; out of them, 37 patients had isolated Vac As1 variants, 11 patients had combined Vac As1 and Cag A variants, and 7 patients had combined Vac As1, Cag A and VacAs2 variants. Patients with the combined two or three variances showed significantly deteriorated histopathological features than patients with a single Vac As1 variant (P < 0.05). Latent toxoplasmosis was positive among 35/82 patients. Combined H. pylori and Toxoplasma gondii infection had significantly marked inflammation than patients with isolated infection (P < 0.05).

CONCLUSION

Screening for toxoplasmosis among H. pylori-infected patients is recommended as it is considered a potential risk factor for gastric inflammation severity. H. pylori gastric inflammation may be heightened by Toxoplasma coinfection.

Analyzing the interaction of Helicobacter pylori GAPDH with host molecules and hemin: Inhibition of hemin binding

Glyceraldehyde 3-phosphate dehydrogenase (GAPDH) is a moonlighting enzyme. Apart from its primary role in the glycolytic pathway, in many bacterial species it is found in the extracellular milieu and also on the bacterial surface. Positioning on the bacterial surface allows the GAPDH molecule to interact with many host molecules such as plasminogen, fibrinogen, fibronectin, laminin and mucin etc. This facilitates the bacterial colonization of the host. Helicobacter pylori is a major human pathogen that causes a number of gastrointestinal infections and is the main cause of gastric cancer. The binding analysis of H. pylori GAPDH (HpGAPDH) with host molecules has not been carried out. Hence, we studied the interaction of HpGAPDH with holo-transferrin, lactoferrin, haemoglobin, fibrinogen, fibronectin, catalase, plasminogen and mucin using biolayer interferometry. Highest and lowest binding affinity was observed with lactoferrin (4.83 ± 0.70 × 10-9 M) and holo-transferrin (4.27 ± 2.39 × 10-5 M). Previous studies established GAPDH as a heme chaperone involved in intracellular heme trafficking and delivery to downstream target proteins. Therefore, to get insights into heme binding, the interaction between HpGAPDH and hemin was analyzed. Hemin binds to HpGAPDH with an affinity of 2.10 μM while the hemin bound HpGAPDH does not exhibit activity. This suggests that hemin most likely binds at the active site of HpGAPDH, prohibiting substrate binding. Blind docking of hemin with HpGAPDH also supports positioning of hemin at the active site. Metal ions were found to inhibit the activity of HpGAPDH, suggesting that it also possibly occupies the substrate binding site. Furthermore, with metal-bound HpGAPDH, hemin binding was not observed, suggesting metal ions act as an inhibitor of hemin binding. Since GAPDH has been identified as a heme chaperone, it will be interesting to analyse the biological consequences of inhibition of heme binding to GAPDH by metal ions.

Infiltration to infection: key virulence players of Helicobacter pylori pathogenicity

PURPOSE

This study aims to comprehensively review the multifaceted factors underlying the successful colonization and infection process of Helicobacter pylori (H. pylori), a prominent Gram-negative pathogen in humans. The focus is on elucidating the functions, mechanisms, genetic regulation, and potential cross-interactions of these elements.

METHODS

Employing a literature review approach, this study examines the intricate interactions between H. pylori and its host. It delves into virulence factors like VacA, CagA, DupA, Urease, along with phase variable genes, such as babA, babC, hopZ, etc., giving insights about the bacterial perspective of the infection The association of these factors with the infection has also been added in the form of statistical data via Funnel and Forest plots, citing the potential of the virulence and also adding an aspect of geographical biasness to the virulence factors. The biochemical characteristics and clinical relevance of these factors and their effects on host cells are individually examined, both comprehensively and statistically.

RESULTS

H. pylori is a Gram-negative, spiral bacterium that successfully colonises the stomach of more than half of the world's population, causing peptic ulcers, gastric cancer, MALT lymphoma, and other gastro-duodenal disorders. The clinical outcomes of H. pylori infection are influenced by a complex interplay between virulence factors and phase variable genes produced by the infecting strain and the host genetic background. A meta-analysis of the prevalence of all the major virulence factors has also been appended.

CONCLUSION

This study illuminates the diverse elements contributing to H. pylori's colonization and infection. The interplay between virulence factors, phase variable genes, and host genetics determines the outcome of the infection. Despite biochemical insights into many factors, their comprehensive regulation remains an understudied area. By offering a panoramic view of these factors and their functions, this study enhances understanding of the bacterium's perspective, i.e. H. pylori's journey from infiltration to successful establishment within the host's stomach.

HELICOBACTER PYLORI OIPA VIRULENCE GENE AS A MOLECULAR MARKER OF SEVERE GASTROPATHIES

BACKGROUND

Helicobacter pylori is an etiologic agent of gastroduodenal diseases. The microorganism, considered a type I carcinogen, affects about 50% of the global population. H. pylori virulence factors are determinant for the clinical outcome of the infection. The outer inflammatory protein A (oipA) gene encodes an outer membrane adhesin and is related to severe gastropathies, such as gastric cancer.

OBJECTIVE

The aim of this study was to evaluate the association of the oipA gene with the severity of gastroduodenal diseases in dyspeptic patients in region Central Brazil.

METHODS

The polymerase chain reaction (PCR) was used to determine the presence of H. pylori. Samples positives were used for molecular screening of the oipA gene. Gastropathies were categorized as non-severe and severe diseases.

RESULTS

Approximately 68% of patients had H. pylori and 36% were infected with H. pylori oipA+ strains. Infection was significantly associated in patients aged over 44 years (P=0.004). However, there was no association between oipA and patients' age (P=0.89). Approximately 46% of patients infected with oipA+ strains had some severe illness. Gastric adenocarcinoma was the most frequent severe gastropathy. The H. pylori oipA genotype was inversely associated with the severity of gastroduodenal diseases (OR=0.247, 95%CI: 0.0804-0.7149 and P=0.007).

CONCLUSION

The characterization of possible molecular markers will contribute to personalized medicine, impacting the prognosis of patients.

BACKGROUND

• Evidence points to an association between the H. pylori oipA gene and gastropathies.

BACKGROUND

• There is a high prevalence of H. pylori infection with a relevant percentage of oipA+ strains.

BACKGROUND

• More severe gastropathies were observed in those infected with H. pylori oipA+ strains.

The modulatory effect of Lactobacillus gasseri ATCC 33323 on autophagy induced by extracellular vesicles of Helicobacter pylori in gastric epithelial cells in vitro

Helicobacter pylori has been recognized as a true pathogen, which is associated with various gastroduodenal diseases, and gastric adenocarcinoma. The crosstalk between H. pylori virulence factors and host autophagy remains challenging. H. pylori can produce extracellular vesicles (EVs) that contribute to gastric inflammation and malignancy. Some probiotic strains have been documented to modulate cell autophagy process. This study was aimed to investigate the modulatory effect of cell-free supernatant (CFS) obtained from Lactobacillus gasseri ATCC 33323 on autophagy induced by H. pylori-derived EVs. EVs were isolated from two clinical H. pylori strains (BY-1 and OC824), and characterized using transmission electron microscopy (TEM) and dynamic light scattering (DLS). The viability of AGS cells was assessed after exposure to different concentrations of H. pylori EVs, and L. gasseri CFS. Based on MTT assay and Annexin V-FITC/PI staining, 50 μg/ml of H. pylori EVs and 10 % v/v of L. gasseri CFS were used for further cell treatment experiments. Autophagy was examined using acridin orange (AO) staining, RT-qPCR analysis for autophagy mediators (LC3B, ATG5, ATG12, ATG16L1, BECN1, MTOR, and NOD1), and western blotting for LC3B expression. H. pylori EVs were detected to range in size from 50 to 200 nm. EVs of both H. pylori strains and L. gasseri CFS showed no significant effect on cell viability as compared to untreated cells. H. pylori EVs promoted the development of acidic vesicular organelles and the expression of autophagy-related genes (LC3B, ATG5, ATG12, ATG16L1, BECN1, and NOD1), and decreased the expression of MTOR in AGS cells at 12 and 24 h time periods. In addition, the production of LC3B was increased following 12 h of treatment in AGS cells. In contrast, L. gasseri CFS effectively inhibited EVs-induced autophagy, as evidenced by reduced acidic vesicular organelle formation and modulation of autophagy markers. Our study indicated that L. gasseri CFS can effectively suppress H. pylori EV-induced autophagy in AGS cells. Further investigations are required to decipher the mechanism of action L. gasseri CFS and its metabolites on autophagy inhibition induced by H. pylori.

Antagonizing roles of SHP1 in the pathogenesis of Helicobacter pylori infection

BACKGROUND

SHP1 has been documented as a tumor suppressor and it was thought to play an antagonistic role in the pathogenesis of Helicobacter pylori infection. In this study, the exact mechanism of this antagonistic action was studied.

MATERIALS AND METHODS

AGS, MGC803, and GES-1 cells were infected with H. pylori, intracellular distribution changes of SHP1 were first detected by immunofluorescence. SHP1 overexpression and knockdown were then constructed in these cells to investigate its antagonistic roles in H. pylori infection. Migration and invasion of infected cells were detected by transwell assay, secretion of IL-8 was examined via ELISA, the cells with hummingbird-like alteration were determined by microexamination, and activation of JAK2/STAT3, PI3K/Akt, and ERK pathways were detected by immunoblotting. Mice infection model was established and gastric pathological changes were evaluated. Finally, the SHP1 activator sorafenib was used to analyze the attenuating effect of SHP1 activation on H. pylori pathogenesis in vitro and in vivo.

RESULTS

The sub-localization of SHP1 changed after H. pylori infection, specifically that the majority of the cytoplasmic SHP1 was transferred to the cell membrane. SHP1 inhibited H. pylori-induced activation of JAK2/STAT3 pathway, PI3K/Akt pathway, nuclear translocation of NF-κB, and then reduced EMT, migration, invasion, and IL-8 secretion. In addition, SHP1 inhibited the formation of CagA-SHP2 complex by dephosphorylating phosphorylated CagA, reduced ERK phosphorylation and the formation of CagA-dependent hummingbird-like cells. In the mice infection model, gastric pathological changes were observed and increased IL-8 secretion, indicators of cell proliferation and EMT progression were also detected. By activating SHP1 with sorafenib, a significant curative effect against H. pylori infection was obtained in vitro and in vivo.

CONCLUSIONS

SHP1 plays an antagonistic role in H. pylori pathogenesis by inhibiting JAK2/STAT3 and PI3K/Akt pathways, NF-κB nuclear translocation, and CagA phosphorylation, thereby reducing cell EMT, migration, invasion, IL-8 secretion, and hummingbird-like changes.

Helicobacter pylori infection in humans and phytotherapy, probiotics, and emerging therapeutic interventions: a review

The global prevalence of Helicobacter pylori (H. pylori) infection remains high, indicating a persistent presence of this pathogenic bacterium capable of infecting humans. This review summarizes the population demographics, transmission routes, as well as conventional and novel therapeutic approaches for H. pylori infection. The prevalence of H. pylori infection exceeds 30% in numerous countries worldwide and can be transmitted through interpersonal and zoonotic routes. Cytotoxin-related gene A (CagA) and vacuolar cytotoxin A (VacA) are the main virulence factors of H. pylori, contributing to its steep global infection rate. Preventative measures should be taken from people's living habits and dietary factors to reduce H. pylori infection. Phytotherapy, probiotics therapies and some emerging therapies have emerged as alternative treatments for H. pylori infection, addressing the issue of elevated antibiotic resistance rates. Plant extracts primarily target urease activity and adhesion activity to treat H. pylori, while probiotics prevent H. pylori infection through both immune and non-immune pathways. In the future, the primary research focus will be on combining multiple treatment methods to effectively eradicate H. pylori infection.

Rubropunctatin-silver composite nanoliposomes for eradicating Helicobacter pylori in vitro and in vivo

Helicobacter pylori (H. pylori) is a major factor in peptic ulcer disease and gastric cancer, and its infection rate is rising globally. The efficacy of traditional antibiotic treatment is less effective, mainly due to bacterial biofilms and the formation of antibiotic resistance. In addition, H. pylori colonizes the gastrointestinal epithelium covered by mucus layers, the drug must penetrate the double barrier of mucus layer and biofilm to reach the infection site and kill H. pylori. The ethanol injection method was used to synthesize nanoliposomes (EPI/R-AgNPs@RHL/PC) with a mixed lipid layer containing rhamnolipids (RHL) and phosphatidylcholine (PC) as a carrier, loaded with the urease inhibitor epiberberine (EPI) and the antimicrobial agent rubropunctatin silver nanoparticles (R-AgNPs). EPI/R-AgNPs@RHL/PC had the appropriate size, negative charge, and acid sensitivity to penetrate mucin-rich mucus layers and achieve acid-responsive drug release. In vitro experiments demonstrated that EPI/R-AgNPs@RHL/PC exhibited good antibacterial activity, effectively inhibited urease activity, removed the mature H. pylori biofilm, and inhibited biofilm regeneration. In vivo antibacterial tests showed that EPI/R-AgNPs@RHL/PC exhibited excellent activity in eradicating H. pylori and protecting the mucosa compared to the traditional clinical triple therapy, providing a new idea for the treatment of H. pylori infection.

Histopathological Findings in Adult Patients With Dyspepsia and Their Association With Helicobacter pylori Infection

BACKGROUND

Helicobacter pylori infection is prevalent among Saudi adults and has been linked to gastric cancer and other tumor-like conditions. We aimed to explore the pathological characteristics of endoscopic gastric biopsies among symptomatic adult Saudi patients and their relation to H. pylori infection.

RESULTS

Among 151 gastric biopsies, gastritis was detected in 97 (64.2%) cases, chronic active gastritis in 26 patients (17.2%), duodenitis in 20 (13.2%) patients, and total metaplasia in 14 (9.3%) patients. H. pylori was detected in 83 cases (55%), with a recurrence or reinfection rate of 9.8%. The patients with H. pylori infection were considerably young (median age: 34 (IQR: 15) vs. 35.5 (IQR: 11), p = 0.024) and had a low frequency of epigastric pain (78.3% vs. 91.2%, p = 0.031), reflux/regurgitation (7.2% vs. 20.6%, p = 0.016), and dysphagia (4.85% vs. 14.7%, p = 0.037). However, they exhibited a higher incidence of chronic active gastritis (96.2% vs. 3.8%, p < 0.001) and intestinal metaplasia (85.7% vs. 14.3%, p = 0.015). Young age (OR = 1.09, 95% CI = 1.02-1.16, p = 0.011) and H. pylori infection (OR = 30.85, 95% CI = 3.26-291.60, p = 0.003) were identified as a positive predictor of intestinal metaplasia while heartburn (OR = 0.08, 95% CI = 0.01-0.58, p = 0.012) was a negative predictor.

CONCLUSION

H. pylori infection is prevalent among Saudi adults experiencing upper gastrointestinal symptoms and is associated with intestinal metaplasia. Infection rate and intestinal metaplasia were higher in patients with milder symptoms. Therefore, screening for H. pylori is highly recommended for Saudi individuals with upper gastrointestinal symptoms. Old age and H. pylori infection were identified as positive predictors of intestinal metaplasia, emphasizing the importance of early detection and management of H. pylori infection in the Saudi population.

Mixed (multiple-genotype) Helicobacter pylori infections in Bulgarian patients

The aim of the study was to evaluate the frequency and characteristics of mixed (multiple-genotype) Helicobacter pylori infections (MGIs) in 155 Bulgarian symptomatic patients (21 children and 134 adults). MGIs were common (36.1%), including double-strain (34.8%) and triple-strain infections (1.3%). None of the 8 ulcer patients harbored multiple subtypes. We detected 18 multiple allelic combinations, of which the most frequent subtypes (17.4%) were vacA s1as2 and vacA s1cs2. The 2 patients with triple-strain infections had vacA s1bs1cs2i1i2/iceA1A2 and vacA s1as1cs2 subtypes. They were both adult men with chronic gastritis and both were examined in 2022. The prevalence of MGIs (51.7%) was 2-fold higher in 2020 to 2022 than in 2015 to 2019 (26.3%). Putative factors for the increase may be the patient's characteristics and COVID-19 pandemic-associated factors. MGI rates corresponded to the high infection seroprevalence (72.4% in 2011) in Bulgaria. The evolution and clinical importance of mixed H. pylori infections merit extensive evaluation.

Both extracellular vesicles from helicobacter pylori-infected cells and helicobacter pylori outer membrane vesicles are involved in gastric/extragastric diseases

Bacterial-derived extracellular vesicles (EVs) have emerged as crucial mediators in the cross-talk between hosts and pathogens, playing a significant role in infectious diseases and cancers. Among these pathogens, Helicobacter pylori (H. pylori) is a particularly important bacterium implicated in various gastrointestinal disorders, gastric cancers, and systemic illnesses. H. pylori achieves these effects by stimulating host cells to secrete EVs and generating internal outer membrane vesicles (OMVs). The EVs derived from H. pylori-infected host cells modulate inflammatory signaling pathways, thereby affecting cell proliferation, apoptosis, cytokine release, immune cell modification, and endothelial dysfunction, as well as disrupting cellular junctional structures and inducing cytoskeletal reorganization. In addition, OMVs isolated from H. pylori play a pivotal role in shaping subsequent immunopathological responses. These vesicles incite both inflammatory and immunosuppressive reactions within the host environment, facilitating pathogen evasion of host defenses and invasion of host cells. Despite this growing understanding, research involving H. pylori-derived EVs remains in its early stages across different domains. In this comprehensive review, we present recent advancements elucidating the contributions of EV components, such as non-coding RNAs (ncRNAs) and proteins, to the pathogenesis of gastric and extragastric diseases. Furthermore, we highlight their potential utility as biomarkers, therapeutic targets, and vehicles for targeted delivery.

A tuft cell - ILC2 signaling circuit provides therapeutic targets to inhibit gastric metaplasia and tumor development

Although gastric cancer is a leading cause of cancer-related deaths, systemic treatment strategies remain scarce. Here, we report the pro-tumorigenic properties of the crosstalk between intestinal tuft cells and type 2 innate lymphoid cells (ILC2) that is evolutionarily optimized for epithelial remodeling in response to helminth infection. We demonstrate that tuft cell-derived interleukin 25 (IL25) drives ILC2 activation, inducing the release of IL13 and promoting epithelial tuft cell hyperplasia. While the resulting tuft cell - ILC2 feed-forward circuit promotes gastric metaplasia and tumor formation, genetic depletion of tuft cells or ILC2s, or therapeutic targeting of IL13 or IL25 alleviates these pathologies in mice. In gastric cancer patients, tuft cell and ILC2 gene signatures predict worsening survival in intestinal-type gastric cancer where ~40% of the corresponding cancers show enriched co-existence of tuft cells and ILC2s. Our findings suggest a role for ILC2 and tuft cells, along with their associated cytokine IL13 and IL25 as gatekeepers and enablers of metaplastic transformation and gastric tumorigenesis, thereby providing an opportunity to therapeutically inhibit early-stage gastric cancer through repurposing antibody-mediated therapies.

Effect of the switch status of Helicobacter pylori outer inflammatory protein A on gastric diseases

Helicobacter pylori OipA (Outer Inflammatory Protein A) is an outer membrane protein that takes role in the adherence and colonization to the stomach. oipA gene expression is regulated by the slipped-strand mispairing mechanism through a hypermutable CT dinucleotide repeat motif in the 5΄ region. Alterations in the CT number repeats cause frame-shift mutations to result in phase variation of oipA expression. While a functional "On" status has been recognized as a risk factor for peptic ulcer diseases and gastric cancer in many studies, some controversial findings still exist. To this end, this study compiled the sequence data of oipA from 10 different studies between 2000-2019 and 50 oipA DNA sequences from our own research that examined the relationship between the phase On/Off status of oipA and gastric diseases based on CT repeat number. Overall, we have reached 536 oipA DNA sequences from patients. This large collection of oipA sequences first clarified the absolute conservation of the peptide-pentamer of FWLHA for phase ''On'' status, suggesting this pentamer as a superior marker for the determination of oipA status than counting the number of CT repeats. Combining the sequence and patient data, we have re-analyzed the association between the ''On'' status of oipA and gastric diseases. Our results showed a strong association between oipA ''On'' status and gastric cancer supporting previous findings. We also investigated the AlphaFold2 computed structure of OipA that adopts a beta-barrel fold closely resembling to the autotransporter family of H. pylori. Altogether, this study confirms a strong association between oipA ''On'' statuses and severe gastrointestinal diseases like cancer and provides useful insights into the FWLHA pentamer as an indicator of "On" status of oipA putative autotransporter function rather than CT repeats number.

Synthesis, Docking Studies and Evaluation of Chalcones as Anti-Helicobacter pylori and antitumoral Agents

Helicobacter pylori colonizes the gastric epithelium of 50 % of world population and it is the main etiological agent of human chronic gastritis, peptic ulcer, and gastric cancer. In this study, we synthesized and characterized a series of 14 chalcones and evaluated their anti-H. pylori, NO inhibition (in vitro and in silico), and AGS cells cytotoxic effects. Compounds 3b and 3h showed MIC of 8 μg/mL. We observed structure-activity relationships, mainly related to the influence of methoxy substituent at C-2 (3b) and the nitro group at C-4 (3h) in chalcone scaffold. The fourteen chalcones inhibited the NO production in LPS-stimulated macrophages and showed potential for interaction on the active site of the iNOS enzyme. Finally, 3b and 3h showed the highest selectivity to the AGS cell lines. Thus, ours results suggest 3b and 3h as potential candidates for design of new and effective agents against H. pylori and related diseases.

Helicobacter pylori-derived outer membrane vesicles suppress liver autophagy: A novel mechanism for H. pylori-mediated hepatic disorder

BACKGROUND

Helicobacter pylori outer membrane vesicles (OMVs) are nano-sized structures, which have been recently suggested to play a crucial role in H. pylori pathogenesis. There are growing evidence indicating the relationship of H. pylori infection with extra-gastroduodenal diseases, especially liver-related disorders. This study was aimed to investigate the effects of H. pylori-derived OMVs on autophagy in hepatic stellate cells (HSCs).

MATERIAL AND METHODS

A selection of five clinical strains of H. pylori with different virulence genotypes were included. The OMVs were isolated by ultracentrifugation and characterized by scanning electron microscopy (SEM) and dynamic light scattering (DLS). The protein concentration of OMVs was measured by BCA assay. MTT assay was used to determine the viability of LX-2 cells (human HSCs) treated with OMVs. The expression level of MTOR, AKT, PI3K, BECN1, ATG16 and LC3B genes was assessed in OMVs-treated LX-2 cells using quantitative real-time PCR. Moreover, immunocytochemistry was performed to evaluate the protein expression of MTOR and LC3B autophagy markers.

RESULTS

H. pylori strains produced round shape nano-vesicles ranging from 50 to 500 nm. Treatment of HSCs with H. pylori-derived OMVs at concentration of 10 μg/mL for 24 h significantly elevated the expression of autophagy inhibitory markers (PI3K, AKT, and MTOR) and suppressed the mRNA expression level of autophagy core proteins (BECN1, ATG16 and LC3B). Immunocytochemistry also presented a substantial reduction in the concentration of LC3B autophagy core protein, and a marked elevation in the amount of MTOR autophagy inhibitory protein.

CONCLUSION

This study revealed that H. pylori-derived OMVs could potentially suppress autophagy flux in HSCs as a novel mechanism for H. pylori-mediated liver autophagy impairment and liver disease development. Further studies are required to elucidate the exact role of OMV-carried contents in liver autophagy, and liver-associated disorders.

The role of microbiota in the development and treatment of gastric cancer

The stomach was once considered a sterile organ until the discovery of Helicobacter pylori (HP). With the application of high-throughput sequencing technology and macrogenomics, researchers have identified fungi and fivemajor bacterial phyla within the stomachs of healthy individuals. These microbial communities exert regulatory influence over various physiological functions, including energy metabolism and immune responses. HP is a well-recognized risk factor for gastric cancer, significantly altering the stomach's native microecology. Currently, numerous studies are centered on the mechanisms by which HP contributes to gastric cancer development, primarily involving the CagA oncoprotein. However, aside from exogenous infections such as HP and EBV, certain endogenous dysbiosis can also lead to gastric cancer through multiple mechanisms. Additionally, gut microbiota and its metabolites significantly impact the development of gastric cancer. The role of microbial therapies, including diet, phages, probiotics and fecal microbiota transplantation, in treating gastric cancer should not be underestimated. This review aims to study the mechanisms involved in the roles of exogenous pathogen infection and endogenous microbiota dysbiosis in the development of gastric cancer. Also, we describe the application of microbiota therapy in the treatment and prognosis of gastric cancer.

Designing and development of multi-epitope chimeric vaccine against Helicobacter pylori by exploring its entire immunogenic epitopes: an immunoinformatic approach

BACKGROUND

Helicobacter pylori is a prominent causative agent of gastric ulceration, gastric adenocarcinoma and gastric lymphoma and have been categorised as a group 1 carcinogen by WHO. The treatment of H. pylori with proton pump inhibitors and antibiotics is effective but also leads to increased antibiotic resistance, patient dissatisfaction, and chances of reinfection. Therefore, an effective vaccine remains the most suitable prophylactic option for mass administration against this infection.

RESULTS

We modelled a multi-chimera subunit vaccine candidate against H. pylori by screening its secretory/outer membrane proteins. We identified B-cell, MHC-II and IFN-γ-inducing epitopes within these proteins. The population coverage, antigenicity, physiochemical properties and secondary structure were evaluated using different in-silico tools, which showed it can be a good and effective vaccine candidate. The 3-D construct was predicted, refined, validated and docked with TLRs. Finally, we performed the molecular docking/simulation and immune simulation studies to validate the stability of interaction and in-silico cloned the epitope sequences into a pET28b(+) plasmid vector.

CONCLUSION

The multiepitope-constructed vaccine contains T- cells, B-cells along with IFN-γ inducing epitopes that have the property to generate good cell-mediated immunity and humoral response. This vaccine can protect most of the world's population. The docking study and immune simulation revealed a good binding with TLRs and cell-mediated and humoral immune responses, respectively. Overall, we attempted to design a multiepitope vaccine and expect this vaccine will show an encouraging result against H. pylori infection in in-vivo use.

Can Pyomelanin Produced by Pseudomonas aeruginosa Promote the Regeneration of Gastric Epithelial Cells and Enhance Helicobacter pylori Phagocytosis?

Helicobacter pylori (H. pylori) infection is the most common cause of chronic gastritis, peptic ulcers and gastric cancer. Successful colonization of the stomach by H. pylori is related to the complex interactions of these bacteria and its components with host cells. The growing antibiotic resistance of H. pylori and various mechanisms of evading the immune response have forced the search for new biologically active substances that exhibit antibacterial properties and limit the harmful effects of these bacteria on gastric epithelial cells and immune cells. In this study, the usefulness of pyomelanin (PyoM) produced by Pseudomonas aeruginosa for inhibiting the metabolic activity of H. pylori was evaluated using the resazurin reduction assay, as well as in vitro cell studies used to verify the cytoprotective, anti-apoptotic and pro-regenerative effects of PyoM in the H. pylori LPS environment. We have shown that both water-soluble (PyoMsol) and water-insoluble (PyoMinsol) PyoM exhibit similar antibacterial properties against selected reference and clinical strains of H. pylori. This study showed that PyoM at a 1 μg/mL concentration reduced H. pylori-driven apoptosis and reactive oxygen species (ROS) production in fibroblasts, monocytes or gastric epithelial cells. In addition, PyoM enhanced the phagocytosis of H. pylori. PyoMsol showed better pro-regenerative and immunomodulatory activities than PyoMinsol.

Identification and characterization of shark VNARs targeting the Helicobacter pylori adhesin HpaA

Helicobacter pylori (H. pylori) is recognized as a pathogen associated with several gastrointestinal diseases. The current treatments exhibit numerous drawbacks, including antibiotic resistance. H. pylori can adhere to and colonize the gastric mucosa through H. pylori adhesin A (HpaA), and antibodies against HpaA may be an effective therapeutic approach. The variable domain of immunoglobulin new antigen receptor (VNAR) is a novel type of single-domain antibody with a small size, good stability, and easy manufacturability. This study isolated VNARs against HpaA from an immune shark VNAR phage display library. The VNARs can bind both recombinant and native HpaA proteins. The VNARs, 2A2 and 3D6, showed high binding affinities to HpaA with different epitopes. Furthermore, homodimeric bivalent VNARs, biNb-2A2 and biNb-3D6, were constructed to enhance the binding affinity. The biNb-2A2 and biNb-3D6 had excellent stability at gastrointestinal pH conditions. Finally, a sandwich ELISA assay was developed to quantify the HpaA protein using BiNb-2A2 as the capture antibody and BiNb-3D6 as the detection antibody. This study provides a potential foundation for novel alternative approaches to treatment or diagnostics applications of H. pylori infection.

Helicobacter pylori infection contributes to the expression of Alzheimer's disease-associated risk factors and neuroinflammation

Over time, mounting evidence has demonstrated extra-gastric manifestations of Helicobacter pylori infection. As such, a number of studies demonstrated the potential contribution of H. pylori infection to the incidence and progression of Alzheimer's disease (AD). Considering unanswered questions regarding the effect of H. pylori infection on brain activity, we sought to investigate the impact of H. pylori infection on the expression of AD-associated risk factors. We used two H. pylori clinical strains obtained from two patients with peptic ulcer and evaluated their influence on the expression level of AD-associated genes (APP, ApoE2, ApoE4, ABCA7, BIN1, Clu, CD33) and genes for inflammatory markers (TLR-4, IL-8, TNF-α) by RT-qPCR in human glioblastoma (U87MG) and astrocyte (1321N1) cell lines. The expression of inflammatory cytokines was further assessed by ELISA assay. The exposure of U97MG and 1321N1 cells to H. pylori strains resulted in a significant enhancement in the expression level of the risk allele ApoE4, while reducing the expression of the protective allele ApoE2. H. pylori infection remarkably increased the expression level of main AD-associated risk genes, and also pro-inflammatory cytokines. Furthermore, we noticed a substantial elevation in the mRNA expression level of transmembrane receptor TLR-4 following H. pylori infection. Our findings presented the potential for H. pylori to stimulate the expression of AD-associated risk genes and trigger neuroinflammation in the brain tissue. This, in principle, leads to the recommendation that AD patients should perhaps test for H. pylori infection and receive treatments upon positive detection.

Histopathological Evaluation of Gastric Mucosal Atrophy for Predicting Gastric Cancer Risk: Problems and Solutions

Patients suffering from chronic gastritis and developing gastric mucosa atrophy are at increased risk of the development of gastric cancer. The diagnosis of chronic atrophic gastritis (CAG) is a complex procedure involving a detailed history taking, a thorough physical examination and the use of laboratory and instrumental diagnostic methods among which the endoscopy of the upper digestive tract is the cornerstone because it allows the assessment of the topography of gastritis and identification of erosions and areas of intestinal metaplasia with the use of NBI endoscopy. However, the diagnosis of CAG requires morphological examination of the gastric mucosa. So, in addition to assessing macroscopic changes in the gastric mucosa, it is necessary to take biopsy specimens in accordance with the protocols for their morphological and immunohistochemical examination. In the absence of specific diagnostic stigmas of CAG, close cooperation between a clinician, endoscopist and pathologist is necessary. The article presents systematized data on the histopathological assessment of the gastric mucosa atrophy to predict the risk of gastric cancer.

Molecular Ensembles of Microbiotic Metabolites in Carcinogenesis

The mechanisms of carcinogenesis are extremely complex and involve multiple components that contribute to the malignant cell transformation, tumor growth, and metastasis. In recent decades, there has been a growing interest in the role of symbiotic human microbiota in the regulation of metabolism and functioning of host immune system. The symbiosis between a macroorganism and its microbiota has given rise to the concept of a holoorganism. Interactions between the components of a holoorganism have formed in the process of coevolution, resulting in the acquisition by microbiotic metabolites of a special role of signaling molecules and main regulators of molecular interactions in the holoorganism. As elements of signaling pathways in the host organism, bacterial metabolites have become essential participants in various physiological and pathological processes, including tumor growth. At the same time, signaling metabolites often exhibit multiple effects and impact both the functions of the host cells and metabolic activity and composition of the microbiome. This review discusses the role of microbiotic metabolites in the induction and prevention of malignant transformation of cells in the host organism and their impact on the efficacy of anticancer therapy, with special emphasis on the involvement of some components of the microbial metabolite molecular ensemble in the initiation and progression of tumor growth.

Liuwei Anxiao San protects gastric mucosa from gastric ulcer in rats by regulating the JAK2/STAT3 pathway

Mongolian medicine prescriptions are recognized as promising gastroprotective agents. This study is to explore the effects and mechanisms of Liuwei Anxiao San (LAS) in gastric ulcer (GU). GU rat models were established using acetic acid, followed by treatment with LAS at different doses and/or the JAK2 agonist Coumermycin A1 (CA1). The ulcerous area and inhibition rates were calculated. The mucosal damage and cell apoptosis in gastric tissues were assessed by H&E and TUNEL staining. The activities of SOD, GSH-Px, and CAT, and MDA levels were measured. The levels of pro-inflammatory and anti-inflammatory factors were determined by ELISA. The activation of the JAK2/STAT3 pathway was determined by Western blot. As the results suggested, LAS dose-dependently ameliorated gastric mucosal damage and inhibited oxidative stress and inflammatory response, evidenced by increased activities of SOD, GSH-Px, and CAT, decreased MDA level, increment of anti-inflammatory factors and decrement of pro-inflammatory factors, and inhibited the activation of the JAK2/STAT3 pathway in GU rats. CA1 partly abolished the function of LAS on gastric mucosal injury, oxidative stress, and inflammation in GU rats. In conclusion, LAS protects against gastric mucosal injury in GU rats through inhibition of oxidative stress and inflammation by suppressing the JAK2/STAT3 pathway.

Crystal structures and solution conformations of HtrA from Helicobacter pylori reveal pH-dependent oligomeric conversion and conformational rearrangements

Helicobacter pylori is a Gram-negative microaerophilic bacterium that infects over 50 % of the world's population, making it a major risk factor for chronic gastritis, ulcer diseases of the stomach and duodenum, MALT lymphoma, and gastric cancer. The clinical consequences of H. pylori infection are closely linked with the expression of virulence factors secreted by the bacterium. One such virulence factor is high temperature requirement A (HtrA), which possesses chaperone and serine protease activity. In the host stomach, HtrA secreted from H. pylori (HpHtrA) disrupts intercellular adhesions by cleaving epithelial adhesion proteins including E-cadherin and desmoglein-2. This disruption causes intercellular junctions to open, allowing the bacterium to pass through the epithelial barrier, access the intercellular space, and colonize the gastric mucosa. HtrA proteases are well known for their structural complexity, reflected in their diverse oligomer forms and multi-tasking activities in both prokaryotes and eukaryotes. In this study, we determined crystal structures and solution conformations of HpHtrA monomer and trimer, which revealed large domain rearrangements between them. Notably, this is the first report of a monomeric structure in the HtrA family. We further found a pH-dependent dynamic trimer-to-monomer conversion and concurrent conformational changes that seem closely linked with a pH-sensing ability through the protonation of certain Asp residues. These results advance our understanding of the functional roles and the related mechanisms of this protease in bacterial infection, which may shed light on the development of HtrA-targeted therapies for H. pylori-associated diseases.

The Human Gastric Juice: A Promising Source for Gastric Cancer Biomarkers

Gastric cancer (GC) is a major public health problem worldwide, with high mortality rates due to late diagnosis and limited treatment options. Biomarker research is essential to improve the early detection of GC. Technological advances and research methodologies have improved diagnostic tools, identifying several potential biomarkers for GC, including microRNA, DNA methylation markers, and protein-based biomarkers. Although most studies have focused on identifying biomarkers in biofluids, the low specificity of these markers has limited their use in clinical practice. This is because many cancers share similar alterations and biomarkers, so obtaining them from the site of disease origin could yield more specific results. As a result, recent research efforts have shifted towards exploring gastric juice (GJ) as an alternative source for biomarker identification. Since GJ is a waste product during a gastroscopic examination, it could provide a "liquid biopsy" enriched with disease-specific biomarkers generated directly at the damaged site. Furthermore, as it contains secretions from the stomach lining, it could reflect changes associated with the developmental stage of GC. This narrative review describes some potential biomarkers for gastric cancer screening identified in gastric juice.

Low Prevalence of HSV-1 and Helicobacter pylori in HNSCC and Chronic Tonsillitis Patients Compared to Healthy Individuals

Recent studies identified viral and bacterial factors, including HSV-1 and H. pylori, as possible factors associated with diseases such as chronic tonsillitis and cancers, including head and neck squamous cell carcinoma (HNSCC). We assessed the prevalence of HSV-1/2 and H. pylori in patients with HNSCC, chronic tonsillitis, and healthy individuals using PCR after DNA isolation. Associations were sought between the presence of HSV-1, H. pylori, and clinicopathological and demographic characteristics and stimulant use. HSV-1 and H. pylori were most frequently identified in controls (HSV-1: 12.5% and H. pylori: 6.3%). There were 7 (7.8%) and 8 (8.6%) patients with positive HSV-1 in HNSCC and chronic tonsillitis patients, respectively, while the prevalence of H. pylori was 0/90 (0%) and 3/93 (3.2%), respectively. More cases of HSV-1 were observed in older individuals in the control group. All positive HSV-1 cases in the HNSCC group were associated with advanced tumor stage (T3/T4). The prevalence of HSV-1 and H. pylori was highest in the controls compared to HNSCC and chronic tonsillitis patients, which indicates that the pathogens were not risk factors. However, since all positive HSV-1 cases in the HNSCC group were observed only in patients with advanced tumor stage, we suggested a possible link between HSV-1 and tumor progression. Further follow-up of the study groups is planned.

Trimer stability of Helicobacter pylori HtrA is regulated by a natural mutation in the protease domain

The human pathogen Helicobacter pylori is a major risk factor for gastric disease development. Serine protease HtrA is an important bacterial virulence factor that cleaves the cell junction proteins occludin, claudin-8 and E-cadherin, which causes gastric tissue damage. Using casein zymography, we discovered that HtrA trimer stability varies in clinical H. pylori strains. Subsequent sequence analyses revealed that HtrA trimer stability correlated with the presence of leucine or serine residue at position 171. The importance of these amino acids in determining trimer stability was confirmed by leucine-to-serine swapping experiments using isogenic H. pylori mutant strains as well as recombinant HtrA proteins. In addition, this sequence position displays a high sequence variability among various bacterial species, but generally exhibits a preference for hydrophilic amino acids. This natural L/S171 polymorphism in H. pylori may affect the protease activity of HtrA during infection, which could be of clinical importance and may determine gastric disease development.

Unwelcome guests - the role of gland-associated Helicobacter pylori infection in gastric carcinogenesis

Helicobacter pylori (H. pylori) are Gram-negative bacteria that cause chronic gastritis and are considered the main risk factor for the development of gastric cancer. H. pylori have evolved to survive the harsh luminal environment of the stomach and are known to cause damage and signaling aberrations in gastric epithelial cells, which can result in premalignant and malignant pathology. As well as colonizing the gastric mucus and surface epithelial cells, a subpopulation of H. pylori can invade deep into the gastric glands and directly interact with progenitor and stem cells. Gland colonization therefore bears the potential to cause direct injury to long-lived cells. Moreover, this bacterial subpopulation triggers a series of host responses that cause an enhanced proliferation of stem cells. Here, we review recent insights into how gastric gland colonization by H. pylori is established, the resulting pro-carcinogenic epithelial signaling alterations, as well as new insights into stem cell responses to infection. Together these point towards a critical role of gland-associated H. pylori in the development of gastric cancer.

Uncovering the special microbiota associated with occurrence and progression of gastric cancer by using RNA-sequencing

Gastric cancer (GC) has been identified as the third deadly cancer in the world. Accumulating researches suggest a potential role of microorganisms in tumorigenesis. However, the composition of microbiota in GC tissues is not clear and it changes throughout the different stages of GC remain mostly elusive. Our study integrated RNA-Seq data of 727 samples derived from gastric tissues across four datasets and revealed its microbial composition. In order to remove the false positive results, core taxa were defined and characterized. Based on it, we analyzed the influence of biological factors on its composition. The pan-microbiome of gastric tissues was estimated to be over than 1400 genera. Seventeen core genera were identified. Among them, Helicobacter, Lysobacter were significantly enriched in normal tissues, while Pseudomonas was enriched in tumor tissues. Interestingly, Acinetobacter, Pasteurella, Streptomyces, Chlamydia, and Lysobacter, showed a significant increase trend during tumor development and formed strong intra/inter-correlations among them or with other genera. Furthermore, we found that tumor stage played an important role in altering the microbial composition of GC tissues. This study provides support for the in-depth study of tumor microbiome, and the specific microbiome excavated provides a possibility for the subsequent identification of potential biomarkers for GC.

Protocatechuic acid, the main effective monomer in Wuqi Powder, can inhibit gastric ulcers induced by acetic acid and Helicobacter pylori

OBJECTIVE

To explore the effective ingredients of Wuqi Powder and their mechanism of action, so as to provide a theoretical basis for clinical application.

METHODS

Enzyme-linked immunosorbent assay was used to determine interleukin 6 (IL-6) and tumor necrosis factor alpha (TNF-α) levels. Rapid urease test and Giemsa staining were conducted to detect Helicobacter pylori (H. pylori) in gastric tissue. CCK-8, EdU and wound healing assay were used to measure the proliferation and migration of GES-1 cells. The number of intracellular and extracellular bacteria of GES-1 cells was counted to evaluate infection and adhesion of H. pylori. RT-qPCR was conducted to evaluate the level of alpA, alpB and cagA genes of H. pylori. Bioinformatics methods were used to predict the potential targets and signaling pathways of protocatechuic acid (PCA) in GES-1 cells. Then, RT-qPCR was used to detect the expression of target genes, and Western blot was conducted to detect the interaction of the target pathways.

RESULTS

PCA is the effective ingredient in Wuqi Powder, which alleviated the symptoms of gastric ulcers, reduced H. pylori in gastric tissue and IL-6, TNF-α in rat serum. In addition, PCA accelerated the proliferation and migration of GES-1 cells and inhibited the infection and adhesion of H. pylori to GES-1 cells. Furthermore, PCA inhibited the TNF and Smad pathways and activated the vascular endothelial growth factor A (VEGFA) pathway of GES-1 cells.

CONCLUSION

PCA is the key component in treating gastric ulcers induced by acetic acid and H. pylori. It promotes gastric ulcer repair by inhibiting the Smad pathway, TNF pathway and activating the VEGFA pathway.

Expression Assessment of the Helicobacter pyloribabA and sabA Genes in Patients with Peptic Ulcer, Duodenal Ulcer and Gastric Cancer

Helicobacter pylori as a common gastrointestinal (GI) pathogen must possess certain virulence characteristics to colonize the stomach, evade host immune responses, and subsequently induce GI diseases. This research aimed to investigate the expression level of two important genes, the sialic acid-binding adherence (SabA) and the blood group antigen-binding adhesion (BabA) in H. pylori strains isolated from adult patients living in the northern part of Iran, and their association with peptic ulcer disease (PUD) and gastric cancer (GC). This cross-sectional study was carried out on adult patients referring to the GI clinic of the hospitals affiliated to Babol University of Medical Sciences, Iran. New cases diagnosed with gastritis, peptic ulcer or gastric cancer were included. Endoscopic-guided gastric biopsies were examined and H. pylori positive colonies were analyzed to determine the expression of babA and sabA genes, utilizing specific primers and the SYBR Green dye. Among 175 patients with mean age of 51.6±15.6 years, 101 (57.7%) of the individuals tested positive for H. pylori infection. Statistical analysis revealed a significant correlation between sabA (P=0.003) and babA (P=0.002) gene expression and development of PUD and GC. Smoking (P=0.052), gender (P=0.004) and positive babA gene expression (P=0.009) had the greatest association with occurrence of PUD or GC in H. pylori positive patients.  In summary, the presence of the sabA gene in people infected with H. pylori increased the risk of GC compared to gastritis, while, the presence of the babA gene was significantly increased in gastric ulcer patients. Considering the diversity of H. pylori isolates and the varying results observed in different geographical regions, further comprehensive studies are required to evaluate the function of these genes in H. pylori pathogenesis and their relationship with clinical outcomes.

Helicobacter pylori and gastric microbiota homeostasis: progress and prospects

Helicobacter pylori, a Gram-negative microaerobic bacteria belonging to the phylum Proteobacteria, can colonize in the stomach and duodenum, and cause a series of gastrointestinal diseases such as gastritis, gastric ulcer and even gastric cancer. At present, the high diversity of the microorganisms in the stomach has been confirmed with culture-independent methods; some researchers have also studied the stomach microbiota composition at different stages of H. pylori carcinogenesis. Here, we mainly review the possible role of H. pylori-mediated microbiota changes in the occurrence and development of gastric cancer to provide new ideas for preventing H. pylori infection and regulating microecological imbalance.

The Effects of Helicobacter pylori-Derived Outer Membrane Vesicles on Hepatic Stellate Cell Activation and Liver Fibrosis In Vitro

Introduction

Helicobacter pylori is a prevalent pathogenic bacterium that resides in the human stomach. Outer membrane vesicles (OMVs) are known as nanosized cargos released by H. pylori, which have been proposed to have a key role in disease progression, pathogenesis, and modulation of the immune system. There are multiple evidences for the role of H. pylori in extragastroduodenal illnesses especially liver-related disorders. However, the precise mechanism of H. pylori extragastroduodenal pathogenesis still remains unclear. In the current study, we aimed to determine the impact of H. pylori-isolated OMVs on hepatic stellate cell (HSC) activation and expression of liver fibrosis markers.

Materials and Methods

Five H. pylori clinical strains with different genotype profiles were used. Helicobacter pylori OMVs were isolated using ultracentrifugation and were analyzed by scanning electron microscopy (SEM) and dynamic light scattering (DLS). Liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) analysis was applied to determine protein components of H. pylori-derived OMVs. Cell viability of LX-2 human hepatic stellate cell line exposed to OMVs was measured by MTT assay. LX-2 cells were treated with OMVs for 24 h. The gene expression of α-SMA, E-cadherin, vimentin, snail, and β-catenin was analyzed using quantitative real-time PCR. The protein expression of α-SMA, as a well-studied profibrotic marker, was evaluated with immunocytochemistry.

Results

Our results showed that H. pylori strains released round shape nanovesicles ranging from 50 to 500 nm. Totally, 112 various proteins were identified in OMVs by proteomic analysis. The isolated OMVs were negative for both CagA and VacA virulence factors. Treatment of HSCs with H. pylori-derived OMVs significantly increased the expression of fibrosis markers.

Conclusions

In conclusion, the present study demonstrated that H. pylori-derived OMVs could promote HSC activation and induce the expression of hepatic fibrosis markers. Further research is required to elucidate the definite role of H. pylori-derived OMVs in liver fibrosis and liver-associated disorders.

Pattern and trends of Helicobacter pylori genotypes in gastric cancer: A Kenyan 8-year study

Background

Notable geographic and temporal variations in the prevalence and genotypes of Helicobacter pylori, in relation to gastric pathologies, have been observed; however, their significance and trends in African populations is scarcely described. The aim of this study, was to investigate the association of H. pylori and its respective CagA and vacuolating cytotoxin A (VacA) genotypes with gastric adenocarcinoma, and to describe the trends of H. pylori genotypes over an 8-year period (2012-2019).

Materials and methods

A total of 286 samples of gastric cancer cases and benign controls (one-to-one matching), from three main cities in Kenya, between 2012 and 2019 were included. Histologic evaluation, and CagA and VacA genotyping using PCR, was performed. Distribution of H. pylori genotypes was presented in proportions. To determine association, a univariate analysis was conducted using a Wilcoxon rank sum test for continuous variables, and a Chi-squared test or Fisher's exact test for categorical data.

Results

The VacA s1m1 genotype was associated with gastric adenocarcinoma, {odds ratio (OR) = 2.68 [confidence interval (CI) of 95%: 0.83-8.65]; p = 0.108}, whilst VacA s2m2 was associated with a reduced probability of gastric adenocarcinoma [OR = 0.23 (CI 95%: 0.07-0.78); p = 0.031]. No association between cytotoxin associated gene A (CagA) and gastric adenocarcinoma was observed.

Conclusion

Over the study period, an increase in all genotypes of H. pylori was seen, and although no predominant genotype was noted, there was significant year-to-year variation, with VacA s1 and VacA s2 showing the greatest variation. VacA s1m1 and VacA s2m2 were associated with increased, and reduced risk of gastric cancer, respectively. Intestinal metaplasia and atrophic gastritis did not appear to be significant in this population.

Gastric Epithelial Barrier Disruption, Inflammation and Oncogenic Signal Transduction by Helicobacter pylori

Helicobacter pylori exemplifies one of the most favourable bacterial pathogens worldwide. The bacterium colonizes the gastric mucosa in about half of the human population and constitutes a major risk factor for triggering gastric diseases such as stomach cancer. H. pylori infection represents a prime example of chronic inflammation and cancer-inducing bacterial pathogens. The microbe utilizes a remarkable set of virulence factors and strategies to control cellular checkpoints of inflammation and oncogenic signal transduction. This chapter emphasizes on the pathogenicity determinants of H. pylori such as the cytotoxin-associated genes pathogenicity island (cagPAI)-encoded type-IV secretion system (T4SS), effector protein CagA, lipopolysaccharide (LPS) metabolite ADP-glycero-β-D-manno-heptose (ADP-heptose), cytotoxin VacA, serine protease HtrA, and urease, and how they manipulate various key host cell signaling networks in the gastric epithelium. In particular, we highlight the H. pylori-induced disruption of cell-to-cell junctions, pro-inflammatory activities, as well as proliferative, pro-apoptotic and anti-apoptotic responses. Here we review these hijacked signal transduction events and their impact on gastric disease development.

Clinical Practice Guidelines of Russian Gastroenterological Association, Scientific Society for the Clinical Study of Human Microbiome, Russian Society for the Prevention of Non-Communicable Diseases, Interregional Association for Clinical Microbiology and Antimicrobial Chemotherapy for <i>H. pylori</i> Diagnostics and Treatment in Adults

Aim: bring to the attention of practitioners indications for anti-Helicobacter therapy, methods and procedure for diagnostics and eradication therapy of Н. pylori infection.

Key points. Chronic gastritis caused by Н. pylori infection, including asymptomatic persons, may be considered as an indication for eradication therapy of Н. pylori as etiological therapy and opportunistic screening for gastric cancer prevention. Indications, for obligatory anti-Helicobacter therapy include peptic ulcer, gastric MALT lymphoma, early gastric cancer (EGC) with endoscopic resection. H. pylori primary diagnostics methods include 13C-urea breath test, H. pylori stool antigen lab test, rapid urease test and serological method. The serological method cannot be used after anti-Helicobacter therapy.

In Russia H. pylori strains' resistance to clarithromycin does not exceed 15 % in most regional studies. The first line therapy for Н. pylori infection eradication is the standard triple therapy including a proton pump inhibitor (PPI), clarithromycin and amoxicillin, enhanced with bismuthate tripotassium dicitrate. A classic four-component therapy based on bismuthate tripotassium dicitrate or quadrotherapy without bismuth drug products which includes PPI, amoxicillin, clarithromycin and metronidazole, may be used as alternative to the first line eradication therapy. The standard triple therapy may be prescribed for 14 days only in those regions, where it has been proven to be effective. Quadrotherapy with bismuthate tripotassium dicitrate is also used as main second line therapy in case of standard triple therapy, bismuth enhanced standard triple therapy or combined therapy failure. Another second line therapy includes PPI, levofloxacin and amoxicillin, to which a bismuth-containing drug product may be added. The third line therapy is selected individually based on previously used treatment settings.

Conclusion. In each case of H. pylori infection the decision for eradication therapy should be made, which is especially relevant as eradication of H. pylori has been recognized as an effective measure for the prevention of gastric cancer.

Clinical Practice Guidelines of Russian Gastroenterological Association, Scientific Society for the Clinical Study of Human Microbiome, Russian Society for the Prevention of Non-Communicable Diseases, Interregional Association for Clinical Microbiology and Antimicrobial Chemotherapy for <i>H. pylori</i> Diagnostics and Treatment in Adults

Aim: bring to the attention of practitioners indications for anti-Helicobacter therapy, methods and procedure for diagnostics and eradication therapy of Н. pylori infection.

Key points. Chronic gastritis caused by Н. pylori infection, including asymptomatic persons, may be considered as an indication for eradication therapy of Н. pylori as etiological therapy and opportunistic screening for gastric cancer prevention. Indications, for obligatory anti-Helicobacter therapy include peptic ulcer, gastric MALT lymphoma, early gastric cancer (EGC) with endoscopic resection. H. pylori primary diagnostics methods include 13C-urea breath test, H. pylori stool antigen lab test, rapid urease test and serological method. The serological method cannot be used after anti-Helicobacter therapy.

In Russia H. pylori strains' resistance to clarithromycin does not exceed 15 % in most regional studies. The first line therapy for Н. pylori infection eradication is the standard triple therapy including a proton pump inhibitor (PPI), clarithromycin and amoxicillin, enhanced with bismuthate tripotassium dicitrate. A classic four-component therapy based on bismuthate tripotassium dicitrate or quadrotherapy without bismuth drug products which includes PPI, amoxicillin, clarithromycin and metronidazole, may be used as alternative to the first line eradication therapy. The standard triple therapy may be prescribed for 14 days only in those regions, where it has been proven to be effective. Quadrotherapy with bismuthate tripotassium dicitrate is also used as main second line therapy in case of standard triple therapy, bismuth enhanced standard triple therapy or combined therapy failure. Another second line therapy includes PPI, levofloxacin and amoxicillin, to which a bismuth-containing drug product may be added. The third line therapy is selected individually based on previously used treatment settings.

Conclusion. In each case of H. pylori infection the decision for eradication therapy should be made, which is especially relevant as eradication of H. pylori has been recognized as an effective measure for the prevention of gastric cancer.

A positive feedback loop of the TAZ/β-catenin axis promotes Helicobacter pylori-associated gastric carcinogenesis

Background

Helicobacter pylori infection is the strongest known risk factor for gastric cancer. The Hippo signaling pathway controls organ size and maintains tissue homeostasis by coordinately regulating cell growth and proliferation. Here, we demonstrate the interactive role of TAZ, the transcriptional coactivator of the Hippo pathway, and beta-catenin in promoting the pathogenesis of H. pylori infection.

Methods

TAZ expression was evaluated in human gastric tissues and H. pylori-infected insulin-gastrin (INS-GAS) mice. Western blot, immunofluorescence, immunohistochemistry, and RT-PCR assays were performed. Coimmunoprecipitation was performed to examine the interaction between TAZ and β-catenin. TAZ and β-catenin were silenced using small interfering RNAs. HA-β-catenin and Flag-TAZ were constructed.

Results

Increased TAZ was noted in human gastric cancer tissues compared to chronic gastritis tissues and in H. pylori-positive gastritis tissues compared to H. pylori-negative gastritis tissues. In addition, H. pylori infection induced TAZ expression and nuclear accumulation in the gastric tissue of INS-GAS mice and cultured gastric epithelial cells, which was dependent on the virulence factor CagA. Moreover, TAZ or β-catenin knockdown significantly suppressed H. pylori infection-induced cell growth, survival, and invasion. Furthermore, the interactive regulation of TAZ and β-catenin activation was revealed. Finally, β-catenin was required for H. pylori-induced TAZ activation.

Conclusion

These findings suggest the existence of a positive feedback loop of activation between TAZ and β-catenin that could play an important role in CagA+ H. pylori infection-induced gastric carcinogenesis. TAZ inhibition represents a potential target for the prevention of H. pylori infection-associated gastric cancer.