The Helicobacter pylori cag pathogenicity island as a determinant of gastric cancer risk

Species-specific components of the Helicobacter pylori Cag type IV secretion system

Helicobacter pylori strains containing the cag pathogenicity island (PAI) deliver an effector protein (CagA) and non-protein substrates into gastric cells through a process that requires the Cag type IV secretion system (T4SS). The Cag T4SS outer membrane core complex (OMCC) contains multiple copies of five proteins, two of which are species-specific proteins. By using modifications of a previously described OMCC immunopurification method and optimized mass spectrometric methods, we have now isolated additional cag PAI-encoded proteins that are present in lower relative abundance. Four of these proteins (CagW, CagL, CagI, and CagH) do not exhibit sequence relatedness to T4SS components in other bacterial species. Size exclusion chromatography analysis of immunopurified samples revealed that CagW, CagL, CagI, and CagH co-elute with OMCC components. These four Cag proteins are copurified with the OMCC in immunopurifications from a Δcag3 mutant strain (lacking peripheral OMCC components), but not from a ΔcagX mutant strain (defective in OMCC assembly). Negative stain electron microscopy analysis indicated that OMCC preparations isolated from ΔcagW, cagL::kan, ΔcagI, and ΔcagH mutant strains are indistinguishable from wild-type OMCCs. In summary, by using several complementary methods, we have identified multiple species-specific Cag proteins that are associated with the Cag T4SS OMCC and are required for T4SS activity.

Microbiota mechanisms in cancer progression and therapy

The composition of the microbiota in patients has been shown to correlate with cancer progression and response to therapy, highlighting unique opportunities to improve patient outcomes. In this review, we discuss the challenges and advancements in understanding the chemical mechanisms of specific microbiota species, pathways, and molecules involved in cancer progression and treatment. We also describe the modulation of cancer and immunotherapy by the microbiota, along with approaches for investigating microbiota enzymes and metabolites. Elucidating these specific microbiota mechanisms and molecules should offer new opportunities for developing enhanced diagnostics and therapeutics to improve outcomes for cancer patients. Nonetheless, many microbiota mechanisms remain to be determined and require innovative chemical genetic approaches.

Nanomaterials: A Prospective Strategy for Biofilm-Forming Helicobacter pylori Treatment

Helicobacter pylori (H. pylori) is prevalent in over 50% of the global population and is recognized as the primary etiological agent for the development of gastric cancer. With the increasing incidence of antibiotic resistance, clinical treatment of H. pylori is a significant challenge. The formation of H. pylori biofilm is an important reason for antibiotic resistance and chronic infection, and it is also one of the key obstacles to eradicating H. pylori. H. pylori biofilm acts as a physical barrier, preventing the penetration of antibiotics and increasing the expression of efflux pump genes and drug-resistant gene mutations. Therefore, the treatment of H. pylori biofilm is extremely challenging. Nanomaterials, such as inorganic nanoparticles, lipid-based nanoparticles, and polymeric nanoparticles, which have properties including disrupting bacterial cell membranes, controlling drug release, and overcoming antibiotic resistance, have attracted significant interest. Furthermore, nanomaterials have the ability to treat H. pylori biofilm owing to their unique size, structure, and physical properties, including the inhibition of biofilm formation, enhancement of biofilm permeability, and disruption of mature biofilm. Moreover, nanomaterials have targeting functions and can carry antimicrobial drugs that play a synergistic role, thus providing a prospective strategy for treating H. pylori biofilm. In this review, we summarize the formation and antibiotic-resistance mechanisms of H. pylori biofilm and outline the latest progress in nanomaterials against H. pylori biofilm with the aim of laying the foundation for the development and clinical application of nanomaterials for anti-H. pylori biofilm.

Lactic acid bacteria target NF-κB signaling to alleviate gastric inflammation

Helicobacter pylori (H. pylori) infection and the resulting gastric inflammation are major contributors to gastric cancer development. Probiotics, particularly Lactobacillus, are promising for their anti-inflammatory potential, yet their exact mechanisms in inhibiting H. pylori-induced inflammation are unclear. In our previous study, Lactiplantibacillus plantarum ZJ316 (L. plantarum ZJ316) demonstrated strong anti-inflammatory effects against H. pylori infection in vivo, but its precise mechanisms were not fully understood. Here, we aimed to investigate how L. plantarum ZJ316 inhibits the inflammatory response to H. pylori infection. Our results demonstrated that L. plantarum ZJ316 effectively reduced the expression of pro-inflammatory cytokines in H. pylori-infected AGS cells. Mechanistically, L. plantarum ZJ316 inhibited the NF-κB signaling pathway by preventing the degradation of IκBα, suppressing p65 phosphorylation, and blocking the nuclear translocation of phosphorylated p65. Treatment with the NF-κB inhibitor BAY 11-7082 further decreased tumor necrosis factor-α (TNF-α), interleukin-8 (IL-8), and interleukin-1β (IL-1β) levels, confirming the inhibitory effect of L. plantarum ZJ316 on the NF-κB pathway. In H. pylori-infected mice, oral administration of L. plantarum ZJ316 significantly alleviated inflammatory cell infiltration, reduced TNF-α and pepsinogen II (PGII) levels, and increased interleukin-10 (IL-10) levels in serum. A comparative metagenomic analysis of the gastric microbiota revealed a decrease in Prevotella and Desulfovibrio, alongside an increase in Ligilactobacillus and Akkermansia, supporting the protective effects of L. plantarum ZJ316 and correlating with their decreased inflammatory response. In summary, administration of L. plantarum ZJ316 demonstrated robust anti-inflammatory effects against H. pylori infection by suppressing NF-κB signaling and promoting favorable changes in the gastric microbiota composition. Therefore, L. plantarum ZJ316 holds promise as a novel functional food for protecting the body against H. pylori infection.

Helicobacter pylori CagA and Cag type IV secretion system activity have key roles in triggering gastric transcriptional and proteomic alterations

Colonization of the human stomach with cag pathogenicity island (PAI)-positive Helicobacter pylori strains is associated with increased gastric cancer risk compared to colonization with cag PAI-negative strains. To evaluate the contributions of the Cag type IV secretion system (T4SS) and CagA (a secreted bacterial oncoprotein) to gastric molecular alterations relevant for carcinogenesis, we infected Mongolian gerbils with a Cag T4SS-positive wild-type (WT) H. pylori strain, one of two Cag T4SS mutant strains (∆cagT or ∆cagY), or a ∆cagA mutant for 12 weeks. Histologic staining revealed a biphasic distribution of gastric inflammation severity in WT-infected animals and minimal inflammation in animals infected with mutant strains. Atrophic gastritis (a premalignant condition), dysplasia, and gastric adenocarcinoma were only detected in WT-infected animals with high inflammation scores. Transcriptional profiling, liquid chromatography-tandem mass spectrometry analysis of micro-extracted tryptic peptides, and imaging mass spectrometry revealed more than a thousand molecular alterations in gastric tissues from WT-infected animals with high inflammation scores compared to uninfected tissues and few alterations in tissues from other groups of infected animals. Proteins with altered abundance in animals with severe Cag T4SS-induced inflammation mapped to multiple pathways, including the complement/coagulation cascade and proteasome pathway. Proteins exhibiting markedly increased abundance in tissues from H. pylori-infected animals with severe inflammation included calprotectin components, proteins involved in proteasome activation, polymeric immunoglobulin receptor (PIGR), interferon-inducible guanylate-binding protein (GBP2), lactoferrin, lysozyme, superoxide dismutase, and eosinophil peroxidase. These results demonstrate key roles for CagA and Cag T4SS activity in promoting gastric mucosal inflammation, transcriptional alterations, and proteomic alterations relevant to gastric carcinogenesis.IMPORTANCEHelicobacter pylori colonizes the stomachs of about half of humans worldwide, and its presence is the primary risk factor for the development of stomach cancer. H. pylori strains isolated from humans can be broadly classified into two groups based on whether they contain a chromosomal cag pathogenicity island, which encodes a secreted effector protein (CagA) and components of a type IV secretion system (T4SS). In experiments using a Mongolian gerbil model, we found that severe gastric inflammation and gastric transcriptional and proteomic alterations related to gastric cancer development were detected only in animals infected with a wild-type H. pylori strain containing CagA and an intact Cag T4SS. Mutant strains lacking CagA or Cag T4SS activity successfully colonized the stomach without inducing detectable pathologic host responses. These findings illustrate two different patterns of H. pylori-host interaction.

Resistome and virulome determination in Helicobacter pylori using next-generation sequencing with target-enrichment technology

The identification of Helicobacter pylori infection from gastric biopsy samples requires PCR or bacterial cultures. However, it is difficult to culture H. pylori because it is a fragile bacterium. Next-generation sequencing (NGS) allows direct assessment of the resistome and virulome. Here we describe a new NGS method for studying the resistome and virulome of H. pylori directly from gastric biopsies, based on enrichment analyses and targeted sequencing of H. pylori DNA. In all, 19 DNA samples from human gastric biopsies that tested positive for H. pylori were analyzed. The Agilent SureSelectXT target-enrichment protocol was used with a custom bait library prior to sequencing using the Agilent MagnisDx NGS Library Prep System. NGS sequencing was performed on the Illumina iSeq 100 sequencer using RNA probes for virulence, resistance, and molecular typing genes. The method yielded significant results with a limit of detection of around 1.8e5 CFU per mL H. pylori. Mutations in the 23S rDNA sequence associated with macrolide resistance and in the quinolone resistance-determining region of gyrase A associated with levofloxacin resistance were correctly identified. The results of MLST phylogeny analyses performed after target-enrichment were consistent with those obtained via conventional Sanger sequencing. Among the cagA-positive isolates, the gene was detected correctly, and the vacA genotype was determined. In conclusion, our enrichment method enables rapid assessment of the resistome and virulome of H. pylori directly from fresh gastric biopsies.IMPORTANCEHelicobacter pylori, a bacterium that infects at least 50% of the world population, is often treated by probabilistic antimicrobial therapies due to the lack of antimicrobial resistance data provided by clinical laboratories to clinicians. However, targeted antimicrobial therapies are increasingly recommended to achieve efficient eradication with a limited impact on the gut microbiota and with fewer adverse events for the patient. Recent advancements in next-generation sequencing strategies have opened new opportunities in the diagnosis of H. pylori infection. The significance of our research is the development of a novel next-generation sequencing strategy based on target-enrichment. This approach enables the identification of the resistome and the virulome of H. pylori directly from gastric biopsies, providing clinicians with a broad overview of therapeutic options.

Helicobacter pylori-related serum indicators: Cutting-edge advances to enhance the efficacy of gastric cancer screening

Helicobacter pylori (H. pylori) infection induces pathological changes via chronic inflammation and virulence factors, thereby increasing the risk of gastric cancer development. Compared with invasive examination methods, H. pylori-related serum indicators are cost-effective and valuable for the early detection of gastric cancer (GC); however, large-scale clinical validation and sufficient understanding of the specific molecular mechanisms involved are lacking. Therefore, a comprehensive review and analysis of recent advances in this field is necessary. In this review, we systematically analyze the relationship between H. pylori and GC and discuss the application of new molecular biomarkers in GC screening. We also summarize the screening potential and application of anti-H. pylori immunoglobulin G and virulence factor-related serum antibodies for identifying GC risk. These indicators provide early warning of infection and enhance screening accuracy. Additionally, we discuss the potential combination of multiple screening indicators for the comprehensive analysis and development of emerging testing methods to improve the accuracy and efficiency of GC screening. Although this review may lack sufficient evidence due to limitations in existing studies, including small sample sizes, regional variations, and inconsistent testing methods, it contributes to advancing personalized precision medicine in high-risk populations and developing GC screening strategies.

New perspectives on gastric disorders: the relationship between innate lymphoid cells and microbes in the stomach

A growing number of studies in recent years have revealed the changes in the gastric microbiota during the development of gastric diseases, breaking the stereotype that the stomach is hostile to microorganisms beyond H. pylori. After a decade of intensive research, the discovery of innate lymphoid cells (ILCs) has provided a new perspective on the immune response in many diseases. In the context of defense against infectious pathogens, the pre-existing innate defense mechanism of tissue-resident ILCs can rapidly recognize and respond to microbes to eliminate infection at the earliest stages. Here, we outline the basic function of ILCs in the gastric mucosa and in shaping the gastric microbiome. We discuss the interactions between the gastric microbiota and ILCs, explaining how the ILCs actively drive the immune response against bacterial pathogens that can lead to the development of the gastric disease.

Molecular investigation of an epidemic dissemination of vancomycin-resistant Enterococcus faecium sequence type 80 in Guangdong province, China

BACKGROUND

The detection rate of vancomycin-resistant Enterococcus faecium (VREfm) displayed a dramatic increase in Guangdong, China, from 2021 to 2023, for which the molecular epidemiology and genomic characteristics remain largely unexplored. In this study, we investigated the genetic features and epidemiology of VREfm isolates in Guangdong.

METHODS

A total of 54 Guangdong VREfm isolates were collected from three tertiary hospitals in Guangdong. We preformed antimicrobial susceptibility tests, whole genome sequencing, risk factor analysis, and bioinformatics analysis to conduct this research.

RESULTS

Our investigation indicated that VREfm isolates were highly clonal and multidrug-resistant ST80 Enterococcus faecium harboring vanA-positive plasmid. Phylogenetic analysis based on single-nucleotide polymorphisms (SNPs) demonstrated that VREfm isolates exhibited minimal genetic similarity to previously reported E. faecium in China, whereas they exhibited high genomic similarity to an India strain A10290 isolated in 2019 and Hiroshima isolates detected in 2020, indicative of a possible exogeneous import. The genetic environment of cps region showed a novel type of wzy gene cluster involved in capsule polysaccharide (CPS) biosynthesis flanked by ISEf1 and IS16 identified in VREfm isolates, which displayed a remarkably divergence from the downstream of putative cpsABCD region in other sequence types (STs) E. faecium. Heat map of plasmid-mediated virulence factors suggested that several predicted proteins including Cag pathogenetic island proteins existed in VREfm isolates at a high frequency.

CONCLUSIONS

This study highlighted the importance of ongoing surveillance to track the dynamic dissemination of multidrug-resistant ST80 VREfm isolates harboring multiple virulence genes in Guangdong Province, China.

Helicobacter pylori infection process: from the molecular world to clinical treatment

Helicobacter pylori is a gram-negative microaerophilic microorganism intricately associated with chronic gastrointestinal disorders and gastric cancer. H. pylori can cause various upper digestive tract diseases, including chronic gastritis, peptic ulcer, gastroesophageal reflux disease, and gastric cancer. The bacterium exhibits a variety of pathogenic mechanisms, including colonization, the expression of virulence factors, and the development of drug resistance. This article presents a comprehensive review of H. pylori pathogenesis, emphasizing recent research advancements concerning the cytotoxin-associated gene A, vacuolating cytotoxin, outer membrane proteins, and other virulence factors. Additionally, it examines the molecular mechanisms underlying drug resistance and evaluates the efficacy of conventional therapeutic approaches. Recently, researchers have attempted novel therapeutic regimens, including probiotics and Chinese medicine-assisted therapies, to enhance therapeutic effects. This article aimed to offer an overview of the academic community's comprehension of H. pylori infection and to highlight the current treatment options.

Traditional Chinese Medicine in the treatment of chronic atrophic gastritis, precancerous lesions and gastric cancer

ETHNOPHARMACOLOGICAL RELEVANCE

Chronic atrophic gastritis (CAG), precancerous lesions of gastric cancer (PLGC), and gastric cancer (GC), seriously threaten human health. Traditional Chinese medicine (TCM) has been employed in the treatment of chronic diseases for a long time and has shown remarkable efficacy.

AIM OF THE STUDY

Recently, there has been an increasing use of TCM in treating CAG, PLGC, and GC. The objective of this study is to compile a comprehensive overview of the existing research on the effects and molecular mechanisms of TCM, including formulas, single herbs, and active components.

MATERIALS AND METHODS

To obtain a comprehensive understanding of traditional use of TCM in treating these diseases, we reviewed ancient books and Chinese literature. In addition, keywords such as "TCM", "CAG", "PLGC", "GC", and "active ingredients" were used to collect modern research on TCM published in databases such as CNKI, Web of Science, and Pubmed up to April 2024. All collected information was then summarized and analyzed.

RESULTS

This study analyzed 174 articles, which covered the research progress of 20 TCM formulas, 14 single herbs, and 50 active ingredients in treating CAG, PLGC, and GC. Sources, effects, and molecular mechanisms of the TCM were summarized.

CONCLUSIONS

This article reviews the progress of TCM in the management of CAG, PLGC, and GC, which will provide a foundation for the clinical application and further development of TCM.

Helicobacter pylori and gastric cancer: mechanisms and new perspectives

Gastric cancer remains a significant global health challenge, with Helicobacter pylori (H. pylori) recognized as a major etiological agent, affecting an estimated 50% of the world's population. There has been a rapidly expanding knowledge of the molecular and pathogenetic mechanisms of H. pylori over the decades. This review summarizes the latest research advances to elucidate the molecular mechanisms underlying the H. pylori infection in gastric carcinogenesis. Our investigation of the molecular mechanisms reveals a complex network involving STAT3, NF-κB, Hippo, and Wnt/β-catenin pathways, which are dysregulated in gastric cancer caused by H. pylori. Furthermore, we highlight the role of H. pylori in inducing oxidative stress, DNA damage, chronic inflammation, and cell apoptosis-key cellular events that pave the way for carcinogenesis. Emerging evidence also suggests the effect of H. pylori on the tumor microenvironment and its possible implications for cancer immunotherapy. This review synthesizes the current knowledge and identifies gaps that warrant further investigation. Despite the progress in our previous knowledge of the development in H. pylori-induced gastric cancer, a comprehensive investigation of H. pylori's role in gastric cancer is crucial for the advancement of prevention and treatment strategies. By elucidating these mechanisms, we aim to provide a more in-depth insights for the study and prevention of H. pylori-related gastric cancer.

A unique Helicobacter pylori strain to study gastric cancer development

Helicobacter pylori colonizes a majority of the human population worldwide and can trigger development of a variety of gastric diseases. Since the bacterium is classified as a carcinogen, elucidation of the characteristics of H. pylori that influence gastric carcinogenesis is a high priority. To this end, the Mongolian gerbil infection model has proven to be an important tool to study gastric cancer progression. However, only a small number of H. pylori strains have been evaluated in the gerbil model. Thus, to identify additional strains able to colonize and induce disease in this model, several H. pylori strains were used to infect Mongolian gerbils, and stomachs were harvested at multiple timepoints to assess colonization and gastric pathology. The USU101 strain reproducibly colonized Mongolian gerbils and induced gastric inflammation in the majority of the animals 1 month after infection. Adenocarcinoma or dysplasia was observed in the majority of gerbils by 2 months post-infection. To define the contribution of key virulence factors to this process, isogenic strains lacking cagA or vacA, along with restorant strains containing a wild-type (WT) copy of the genes, were studied. The ΔcagA USU101 strain colonized gerbils at levels similar to WT, but did not induce comparable levels of inflammation or disease. In contrast, the ΔvacA USU101 strain did not colonize gerbils, and the stomach pathology resembled that of the mock-infected animals. The restorant USU101 strains expressed the CagA and VacA proteins in vitro, and in vivo experiments with Mongolian gerbils showed a restoration of colonization levels and inflammation scores comparable to those observed in WT USU101. Our studies indicate that the USU101 strain is a valuable tool to study H. pylori-induced disease.IMPORTANCEGastric cancer is the fifth leading cause of cancer-related death globally; the majority of gastric cancers are associated with Helicobacter pylori infection. Infection of Mongolian gerbils with H. pylori has been shown to result in induction of gastric cancer, but few H. pylori strains have been studied in this model; this limits our ability to fully understand gastric cancer pathogenesis in humans because H. pylori strains are notoriously heterogenous. Our studies reveal that USU101 represents a unique H. pylori strain that can be added to our repertoire of strains to study gastric cancer development in the Mongolian gerbil model.

Intestinal metaplasia key molecules and UPP1 activation via Helicobacter pylori /NF-kB: drivers of malignant progression in gastric cancer

Gastric cancer (GC) remains a significant global health challenge due to its high morbidity and mortality rates. The development of GC is a multi-hit process and the exploration of precancerous lesions is crucial. To elucidate the molecular and cellular dynamics underlying gastric carcinogenesis, we conducted an integrative single-cell RNA sequencing analysis of 26,028 high-quality cells from gastric antral mucosa biopsies across various stages, including non-atrophic gastritis, chronic atrophic gastritis, intestinal metaplasia, and early gastric cancer. By constructing a detailed single-cell atlas, we identified distinct epithelial cell subpopulations and their corresponding molecular signatures. We focused on the biological link between gastric epithelial cells and cancer cells. Notably, we observed that gland mucous cells acquired an intestinal-like stem cell phenotype during metaplasia, with MUC6, MUC2 and OLFM4 emerging as the specific markers for unique endocrine cells in early malignant lesions. Additionally, our analysis highlighted UPP1 as a key oncogene, with its expression progressively increasing from normal epithelial cells to malignant cells. UPP1 upregulation was shown to promote GC cell proliferation and migration, implicating it in the oncogenic process. Further, we explored the impact of Helicobacter pylori infection on gene expression, revealing that Helicobacter pylori infection upregulates UPP1 via the NF-κB pathway. Our cell-cell communication analysis underscored the significant role of the Macrophage migration inhibitory factor pathway in the tumor microenvironment, contributing to GC progression. Various key molecules involved in intestinal metaplasia, along with UPP1 and the Macrophage migration inhibitory factor pathway, collectively illustrate the multifaceted nature and complexity of gastric cancer evolution, highlighting the cumulative impacts that drive tumorigenesis.

What defines a healthy gut microbiome?

The understanding that changes in microbiome composition can influence chronic human diseases and the efficiency of therapies has driven efforts to develop microbiota-centred therapies such as first and next generation probiotics, prebiotics and postbiotics, microbiota editing and faecal microbiota transplantation. Central to microbiome research is understanding how disease impacts microbiome composition and vice versa, yet there is a problematic issue with the term 'dysbiosis', which broadly links microbial imbalances to various chronic illnesses without precision or definition. Another significant issue in microbiome discussions is defining 'healthy individuals' to ascertain what characterises a healthy microbiome. This involves questioning who represents the healthiest segment of our population-whether it is those free from illnesses, athletes at peak performance, individuals living healthily through regular exercise and good nutrition or even elderly adults or centenarians who have been tested by time and achieved remarkable healthy longevity.This review advocates for delineating 'what defines a healthy microbiome?' by considering a broader range of factors related to human health and environmental influences on the microbiota. A healthy microbiome is undoubtedly linked to gut health. Nevertheless, it is very difficult to pinpoint a universally accepted definition of 'gut health' due to the complexities of measuring gut functionality besides the microbiota composition. We must take into account individual variabilities, the influence of diet, lifestyle, host and environmental factors. Moreover, the challenge in distinguishing causation from correlation between gut microbiome and overall health is presented.The review also highlights the resource-heavy nature of comprehensive gut health assessments, which hinders their practicality and broad application. Finally, we call for continued research and a nuanced approach to better understand the intricate and evolving concept of gut health, emphasising the need for more precise and inclusive definitions and methodologies in studying the microbiome.

Effects and mechanisms of Helicobacter pylori on cancers development and immunotherapy

Tumor immunotherapy has been widely used in clinical treatment of various cancers. However, some patients of these cancers do not respond to immunotherapy effectively. And H. pylori infection has been considered to be related to the efficacy of immunotherapy. This review aims to summarize the different effects and mechanisms of H. pylori infection on immunotherapy in different kinds of cancers. We searched the relevant literature on H. pylori and tumor immunotherapy, and summarized to form a review. Generally, H. pylori infection plays a role in affecting kinds of cancers' development, besides gastric cancer. Current evidence suggests that H. pylori infection may reduce the efficacy of immunotherapy for colorectal cancer, non-small cell lung cancer and melanoma, but due to the lack of sufficient evidence, more data is needed to prove that. While for gastric cancer, the effects remain controversial. The H. pylori regulation effects and metabolisms involved in systematic related cancers should be paid attention to. Whether H. pylori should be eradicated when immunotherapy performed may be a critical consideration for some kinds of tumors.

Chebulinic acid isolated from aqueous extracts of Terminalia chebula Retz inhibits Helicobacter pylori infection by potential binding to Cag A protein and regulating adhesion

BACKGROUND

Terminalia chebula Retz, known as the King of Tibet, is considered a functional food in China, celebrated for its antioxidant, immune-modulating, antibacterial, and anti-inflammatory properties. Chebulinic acid, derived from aqueous extracts of Terminalia chebula Retz, is known for its anti-inflammatory properties. However, its potential as an anti-Helicobacter pylori (HP) agent has not been fully explored.

METHODS

Herein, we extracted the main compound from Terminalia chebula Retz using a semi-preparative liquid chromatography (LC) system and identified compound 5 as chebulinic acid through Ultra-high performance liquid chromatography-MS/MS (UPLC-MS/MS) and Nuclear Magnetic Resonance (NMR). To evaluate its role, we conducted minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) assays, scanning electron microscope (SEM) imaging, inhibiting kinetics curves, urea fast test, cell counting kit-8 (CCK-8) assay, western blot analysis, griess reagent system, and molecular docking.

RESULTS

Our results showed that chebulinic acid effectively inhibited the growth of the HP strain ATCC 700392, damaged the HP structure, and exhibited selective antimicrobial activity without affecting normal epithelial cells GES-1. Importantly, it suppressed the expression of Cytotoxin-associated gene A (Cag A) protein, a crucial factor in HP infection. Molecular docking analysis predicted a strong affinity (-9.7 kcal/mol) between chebulinic acid and Cag A protein.

CONCLUSION

Overall, our findings suggest that chebulinic acid acts as an anti-adhesive agent, disrupting the adhesion of HP to host cells, which is a critical step in HP infection. It also suppresses the Cag A protein. These results highlight the potential of chebulinic acid against HP infections.

Design of a Helicobacter pylori multi-epitope vaccine based on immunoinformatics

Helicobacter pylori (H. pylori) is an infectious bacterium that colonizes the stomach of approximately half of the global population. It has been classified as a Group I carcinogen by the World Health Organization due to its strong association with an increased incidence of gastric cancer and exacerbation of stomach diseases. The primary treatment for H. pylori infection currently involves triple or quadruple therapy, primarily consisting of antibiotics and proton pump inhibitors. However, the increasing prevalence of antibiotic resistance poses significant challenges to this approach, underscoring the urgent need for an effective vaccine. In this study, a novel multi-epitope H. pylori vaccine was designed using immunoinformatics. The vaccine contains epitopes derived from nine essential proteins. Software tools and online servers were utilized to predict, evaluate, and analyze the physiochemical properties, secondary and tertiary structures, and immunogenicity of the candidate vaccine. These comprehensive assessments ultimately led to the formulation of an optimal design scheme for the vaccine. Through constructing a novel multi-epitope vaccine based on immunoinformatics, this study offers promising prospects and great potential for the prevention of H. pylori infection. This study also provides a reference strategy to develop multi-epitope vaccines for other pathogens.

The immunopathogenesis of Helicobacter pylori-induced gastric cancer: a narrative review

Helicobacter pylori infection is a well-established risk factor for the development of gastric cancer (GC). Understanding the immunopathogenesis underlying this association is crucial for developing effective preventive and therapeutic strategies. This narrative review comprehensively explores the immunopathogenesis of H. pylori-induced GC by delving into several key aspects, emphasizing the pivotal roles played by H. pylori virulence factors, including cytotoxin-associated gene A (cagA) and vacuolating cytotoxin A (vacA), blood group antigen-binding adhesin (babA), and sialic acid binding adhesin (sabA). Moreover, the review focuses on the role of toll-like receptors (TLRs) and cytokines in the complex interplay between chronic infection and gastric carcinogenesis. Finally, the study examines the association between H. pylori evasion of the innate and adaptive immune response and development of GC. A comprehensive understanding of the immunopathogenesis of H. pylori-induced GC is essential for designing targeted interventions to prevent and manage this disease. Further research is warranted to elucidate the intricate immune responses involved and identify potential therapeutic targets to improve patient outcomes.

Candidate Antigens and the Development of Helicobacter pylori Vaccines

BACKGROUND

Infection with Helicobacter pylori (Hp) mostly occurs during childhood, and persistent infection may lead to severe gastric diseases and even gastric cancer. Currently, the primary method for eradicating Hp is through antibiotic treatment. However, the increasing multidrug resistance in Hp strains has diminished the effectiveness of antibiotic treatments. Vaccination could potentially serve as an effective intervention to resolve this issue.

AIMS

Through extensive research and analysis of the vital protein characteristics involved in Hp infection, we aim to provide references for subsequent vaccine antigen selection. Additionally, we summarize the current research and development of Hp vaccines in order to provide assistance for future research.

MATERIALS AND METHODS

Utilizing the databases PubMed and the Web of Science, a comprehensive search was conducted to compile articles pertaining to Hp antigens and vaccines. The salient aspects of these articles were then summarized to provide a detailed overview of the current research landscape in this field.

RESULTS

Several potential antigens have been identified and introduced through a thorough understanding of the infection process and pathogenic mechanisms of Hp. The conserved and widely distributed candidate antigens in Hp, such as UreB, HpaA, GGT, and NAP, are discussed. Proteins such as CagA and VacA, which have significant virulence effects but relatively poor conservatism, require further evaluation. Emerging antigens like HtrA and dupA have significant research value. In addition, vaccines based on these candidate antigens have been compiled and summarized.

CONCLUSIONS

Vaccines are a promising method for preventing and treating Hp. While some Hp vaccines have achieved promising results, mature products are not yet available on the market. Great efforts have been directed toward developing various types of vaccines, underscoring the need for developers to select appropriate antigens and vaccine formulations to improve success rates.

A prominent role of LncRNA H19 in H. pylori CagA induced DNA damage response and cell malignancy

Helicobacter pylori (H. pylori), together with its CagA, has been implicated in causing DNA damage, cell cycle arrest, apoptosis, and the development of gastric cancer. Although lncRNA H19 is abundantly expressed in gastric cancer and functions as a pro-oncogene, it remains unclear whether lncRNA H19 contributes to the oncogenic process of H. pylori CagA. This study investigates the role of H19 in the DNA damage response and malignancy induced by H. pylori. It was observed that cells infected with CagA+ H. pylori strain (GZ7/cagA) showed significantly higher H19 expression, resulting in increased γH2A.X and p-ATM expression and decreased p53 and Rad51 expression. Faster cell migration and invasion was also observed, which was reversed by H19 knockdown in H. pylori. YWHAZ was identified as an H19 target protein, and its expression was increased in H19 knockdown cells. GZ7/cagA infection responded to the increased YWHAZ expression induced by H19 knockdown. In addition, H19 knockdown stimulated cells to enter the G2-phase and attenuated the effect of GZ7/cagA infection on the cellular S-phase barrier. The results suggest that H. pylori CagA can upregulate H19 expression, participate in the DNA damage response and promote cell migration and invasion, and possibly affect cell cycle arrest via regulation of YWHAZ.

Subdomains of the Helicobacter pylori Cag T4SS outer membrane core complex exhibit structural independence

The Helicobacter pylori Cag type IV secretion system (Cag T4SS) has an important role in the pathogenesis of gastric cancer. The Cag T4SS outer membrane core complex (OMCC) is organized into three regions: a 14-fold symmetric outer membrane cap (OMC) composed of CagY, CagX, CagT, CagM, and Cag3; a 17-fold symmetric periplasmic ring (PR) composed of CagY and CagX; and a stalk with unknown composition. We investigated how CagT, CagM, and a conserved antenna projection (AP) region of CagY contribute to the structural organization of the OMCC. Single-particle cryo-EM analyses showed that complexes purified from ΔcagT or ΔcagM mutants no longer had organized OMCs, but the PRs remained structured. OMCCs purified from a CagY antenna projection mutant (CagY∆AP) were structurally similar to WT OMCCs, except for the absence of the α-helical antenna projection. These results indicate that CagY and CagX are sufficient for maintaining a stable PR, but the organization of the OMC requires CagY, CagX, CagM, and CagT. Our results highlight an unexpected structural independence of two major subdomains of the Cag T4SS OMCC.