Gastric cancer (GC) is a globally prevalent malignancy with a particularly heavy burden in China. Helicobacter pylori ( H. pylori ) is a Group I carcinogen for GC, with a higher seroprevalence rate indicating a higher GC incidence. However, only approximately 3% of the individuals with H. pylori infection eventually develop GC, and about 2.6% still progress to GC even 10-20 years after the eradication of H. pylori . Thus, the pathogenic mechanism of H. pylori for GC must be elucidated, and high-risk individuals precisely identified. Furthermore, GC can occur even in individuals who have never been infected with H. pylori . As H. pylori infection rates decline, the proportion of H. pylori -negative GC cases is increasing annually, gaining significant research attention. In this review, potential pathogenic mechanisms of H. pylori infection are explored from the aspects of H. pylori virulence factors and host factors (genetic susceptibility and immune microenvironment). Possible risk factors for H. pylori -negative GC include infections by other microorganisms (e.g., bacteria, fungi, and viruses), autoimmune gastritis, bile reflux, genetic mutations, and environmental factors. We aim to review the potential mechanisms for GC with varying H. pylori infection statuses, identify the high-risk individuals, and pose questions that need to be addressed. In the future, as the prevalence of H. pylori infection gradually decreases, GC prevention and management must evolve to address host-specific factors and the growing challenge of H. pylori -negative GC by integrating multidisciplinary perspectives.
Stomach Neoplasms/genetics* ; Humans ; Helicobacter Infections/complications* ; Helicobacter pylori/pathogenicity* ; Risk Factors

OBJECTIVE: To explore the changes of CKLF-like MARVEL transmembrane domain-containing 6 (CMTM6) and programmed death-ligand 1 (PD-L1) expression in gastric mucosal epithelial cells after Helicobacter pylori infection and the regulation of CMTM6 on PD-L1, and to analyze the mRNA expression differences before and after CMTM6 gene knock-out in helicobacter pylori infected gastric epithelial cells by microarray analysis. METHODS: The standard Helicobacter pylori strain ATCC 26695 was co-cultured with human gastric epithelial cell GES-1 for 6, 24 and 48 hours, and the mRNA and protein levels of CMTM6 and PD-L1 were detected by real-time quantitative PCR and Western blot. Using CRISPR/Cas9 to construct CMTM6 gene knockout plasmid and knockout CMTM6 gene of GES-1 cells. Helicobacter pylori was co-cultured with CMTM6 gene knockout and wild type GES-1 cells for 48 hours to detect PD-L1 transcription and protein level changes, and CMTM6 gene knockout GES-1 cells were treated with the proteasome inhibitor MG-132 to detect the changes in PD-L1 protein levels. Agilent Human ceRNA Microarray 2019 was used to detect the differentially expressed genes in CMTM6 gene knockout and wild-type GES-1 cells co-cultured with Hp for 48 hours, and the signal pathway of differentially expressed genes enrichment was analyzed by Kyoto Encyclopedia of Genes and Genomes (KEGG) database. RESULTS: The mRNA and protein levels of CMTM6 and PD-L1 in GES-1 cells were significantly up-regulated after Helicobacter pylori infection, and CMTM6 mRNA was most significantly up-regulated 48 hours after infection. After CMTM6 gene knockout, the CD274 gene transcription level of Helicobacter pylori infected GES-1 cells did not change significantly, but PD-L1 protein level was significantly down-regulated, and the PD-L1 level increased after the application of proteasome inhibitor MG-132. After CMTM6 gene knockout, 67 genes had more than two times of differential expression. The transcription levels of TMEM68, FERMT3, GPR142, ATP6V1FNB, NOV, UBE2S and other genes were significantly down-regulated. The transcription levels of PCDHGA6, CAMKMT, PDIA2, NTRK3, SPOCK1 and other genes were significantly up-regulated. After CMTM6 gene knockout, ubiquitin-conjugating enzyme E2S (UBE2S) gene expression was significantly down-regulated, which might affect protein ubiquitination degradation. After CMTM6 gene knockout, adrenoceptor alpha 1B (ADRA1B), cholinergic receptor muscarinic 1 (M1), CHRM1, platelet activating factor receptor (PTAFR) gene expression was significantly up-regulated. CONCLUSION Helicobacter pylori infection up-regulates the expression level of CMTM6 in gastric mucosa cells, and CMTM6 can stabilize PD-L1 and maintain the protein level of PD-L1. CMTM6 gene knockout may affect biological behaviors such as protein ubiquitination and cell surface receptor expression.
Humans ; MARVEL Domain-Containing Proteins/metabolism* ; Helicobacter pylori/physiology* ; B7-H1 Antigen/genetics* ; Helicobacter Infections/metabolism* ; Epithelial Cells/metabolism* ; Gastric Mucosa/metabolism* ; Chemokines/metabolism* ; Cell Line ; Gene Knockout Techniques ; Myelin Proteins

Helicobacter pylori is a bacterium that can cause chronic gastritis, peptic ulcers, and other gastrointestinal diseases. The World Health Organization has classified H. pylori as a group Ⅰ carcinogen. Antibiotics are the primary clinical approach for eradicating H. pylori. However, incomplete eradication of H. pylori by antibiotics can lead to persistent infection, which is a major risk factor for the high incidence of gastric cancer. The widespread use of antibiotics has led to the emergence of multidrug resistance in H. pylori, contributing to treatment failures of chronic gastric diseases and increasing the risk of spreading resistant strains. Multidrug-resistant H. pylori has become a serious challenge in the diagnosis and treatment of gastrointestinal diseases. This paper reviews the global trends in the development of multidrug resistance in H. pylori, the underlying mechanisms, the challenges it poses to clinical diagnosis, and its impact on drug development, drawing on relevant literature and the research findings from our group. It proposes using cgt expression as a novel method for determining viable bacteria, identifying intracellularization as a new form of resistance in H. pylori, and exploring the potential of O-glycans as a therapeutic approach against H. pylori to address multidrug resistance. It provides new insights into understanding the mechanisms of H. pylori multidrug resistance and its prevention strategies, offering promising directions for future clinical treatments and antimicrobial drug development.
Helicobacter pylori/genetics* ; Humans ; Drug Resistance, Multiple, Bacterial ; Helicobacter Infections/microbiology* ; Anti-Bacterial Agents/therapeutic use* ; Gastrointestinal Diseases/drug therapy*

Objective To clarify whether Helicobacter pylori (H. pylori) can promote metastasis of gastric cancer cells via the high-expression of induced B cell specific Moloney murine leukemia virus integration site 1 (Bmi-1). Methods The gastric cancer tissue specimens from 82 patients were collected for this study. The protein and gene expression level of Bmi-1 in gastric adenocarcinoma tissue were detected by immunohistochemistry and real time quantitative PCR, respectively. And meanwhile the correlation between Bmi-1 levels and pathological features, and prognosis of gastric cancer were analyzed retrospectively. Then, the GES-1 cells were transfected with pLPCX-Bmi-1 plasmid and infected with H. pylori respectively. After the Bmi-1 overexpression in GES-1 cells, the invasion ability of the GES-1 cells was detected by Transwell assay, and the cell cycle and apoptosis were detected by flow cytometry. Results The mRNA and protein of Bmi-1 expression in gastric cancer tissues were higher than tumor-adjacent tissue, and the high expression of Bmi-1 was positively correlated with tumor invasion, TNM stage, tumor differentiation, lymph node metastasis and H. pylori infection. When expression of Bmi-1 was up-regulated as a result of H.pylori infection or pLPCX-Bmi-1 transfection, the GES-1 cells had higher invasiveness and lower apoptosis rate with the above treatment respectively. Conclusion H. pylori infection can inhibit the apoptosis of gastric cancer cells and promote their invasion via up-regulating expression of Bmi-1.
Humans ; Cell Line, Tumor ; Helicobacter Infections/genetics* ; Helicobacter pylori ; Lymphatic Metastasis ; Retrospective Studies ; Stomach Neoplasms/pathology* ; Polycomb Repressive Complex 1/genetics*

Helicobacter pylori (Hp) is one of most common pathogens causing gastrointestinal disorder including gastric ulcer, duodenal ulcer and gastric cancer, etc. It has been verified as class I carcinogen by WHO. Nowadays, combination antibiotics and proton pump inhibitor are mainly used to erase Hp in clinical application. However, with the increased resistance of Hp, the vaccine against Hp might become the best strategy to eradicate Hp. Elements including urease, virulence factor, outer membrane protein, flagella, play an important role in Hp infection, colonization and reproduction. They have become potential candidate antigens in the development of Hp vaccine, as reported in previous studies. Presently, these antigens-centric vaccines have been tested in animal models. Therefore, this article reviews the studies on Hp vaccine with urease, virulence genes, outer membrane protein and flagella as their candidate antigens, in an attempt to provide insights for research in this regard.
Animals ; Helicobacter pylori ; Urease/genetics* ; Helicobacter Infections/prevention & control* ; Vaccines ; Membrane Proteins

Objective: To investigate the characteristics of duodenal bulbar microbiota in children with duodenal ulcer and Helicobacter pylori (Hp) infection. Methods: This prospective cohort study enrolled 23 children with duodenal ulcers diagnosed by gastroscopy who were admitted to the Children's Hospital of Zhejiang University School of Medicine due to abdominal pain, abdominal distension, and vomiting from January 2018 to August 2018. They were divided into Hp-positive and Hp-negative groups according to the presence or absence of Hp infection. Duodenal bulbar mucosa was sampled to detect the bacterial DNA by high-throughput sequencing. The statistical difference in α diversity and β diversity, and the relative abundance in taxonomic level between the two groups were compared. Microbial functions were predicted using the software PICRUSt. T-test, Rank sum test or χ² test were used for comparison between the two groups. Results: A total of 23 children diagnosed with duodenal ulcer were enrolled in this study, including 15 cases with Hp infection ((11.2±3.3) years of age, 11 males and 4 females) and 8 cases without Hp infection ((10.1±4.4) years of age, 6 males and 2 females). Compared with Hp-negative group, the Hp-positive group had higher Helicobacter abundance (0.551% (0.258%, 5.368%) vs. 0.143% (0.039%, 0.762%), Z=2.00, P=0.045) and lower abundance of Fusobacterium, Streptococcus and unclassified- Comamonadaceae (0.010% (0.001%, 0.031%) vs. 0.049% (0.011%, 0.310%), Z=-2.24, P=0.025; 0.031% (0.015%, 0.092%) vs. 0.118% (0.046%, 0.410%), Z=-2.10, P=0.036; 0.046% (0.036%, 0.062%) vs. 0.110% (0.045%, 0.176%), Z=-2.01, P=0.045). Linear discriminant analysis (LDA) effect sized showed that at the genus level, only Helicobacter was significantly enriched in Hp-positive group (LDA=4.89, P=0.045), while Streptococcus and Fusobacterium significantly enriched in Hp-negative group (LDA=3.28, 3.11;P=0.036,0.025, respectively). PICRUSt microbial function prediction showed that the expression of oxidative phosphorylation and disease-related pathways (pathways in cancer, renal cell carcinoma, amoebiasis, type 1 diabetes mellitus) in Hp-positive group were significantly higher than that in Hp-negative group (all P<0.05), while the expression of pathways such as energy metabolism and phosphotransferase system pathways were significantly lower than that in Hp-negative group (all P<0.05). Conclusion: In children with Hp-infected duodenal ulcers, the mucosal microbiota of the duodenal bulb is altered, characterized by an increased abundance of Helicobacter and a decreased abundance of Clostridium and Streptococcus, and possibly alters the biological function of the commensal microbiota through specific metabolic pathways.
Male ; Female ; Humans ; Child ; Duodenal Ulcer/diagnosis* ; Helicobacter Infections/complications* ; Helicobacter pylori/genetics* ; Prospective Studies ; Microbiota

Objective To evaluate the gastric microbiome in patients with chronic superficial gastritis (CSG) and intestinal metaplasia (IM) and investigate the influence of Helicobacter pylori (H. pylori) on the gastric microbiome. Methods Gastric mucosa tissue samples were collected from 54 patients with CSG and IM, and the patients were classified into the following four groups based on the state of H. pylori infection and histology: H. pylori-negative CSG (n=24), H. pylori-positive CSG (n=14), H. pylori-negative IM (n=11), and H. pylori-positive IM (n=5). The gastric microbiome was analyzed by 16S rRNA gene sequencing. Results H. pylori strongly influenced the bacterial abundance and diversity regardless of CSG and IM. In H. pylori-positive subjects, the bacterial abundance and diversity were significantly lower than in H. pylori-negative subjects. The H. pylori-negative groups had similar bacterial composition and bacterial abundance. The H. pylori-positive groups also had similar bacterial composition but different bacterial relative abundance. The relative abundance of Neisseria, Streptococcus, Rothia, and Veillonella were richer in the I-HP group than in G-HP group, especially Neisseria (t=175.1, P<0.001). Conclusions The gastric microbial abundance and diversity are lower in H. pylori- infected patients regardless of CSG and IM. Compared to H. pylori-positive CSG group and H. pylori-positive IM, the relative abundance of Neisseria, Streptococcus, Rothia, and Veillonella is higher in H. pylori-positive patients with IM than in H. pylori-positive patients with CSG, especially Neisseria.
Gastric Mucosa/microbiology* ; Gastritis, Atrophic/microbiology* ; Gastrointestinal Microbiome/genetics* ; Helicobacter Infections/microbiology* ; Helicobacter pylori/genetics* ; Humans ; Metaplasia ; RNA, Ribosomal, 16S/genetics* ; Stomach Neoplasms

To investigate the mechanism of long non-coding RNA plasmacytoma variant translocation 1 (PVT1) in gastric cancer caused by (HP) infection. The expression of PVT1 was detected by quantitative real-time polymerase chain reaction in HP-infected normal gastric epithelial cells GES-1. Gastric cancer cell line SGC-7901 was transfected with PVT1 small interfering RNA and co-cultured with HP,and then the inflammatory cytokines such as tumor necrosis factor-α (TNF-α),interleukin (IL) -1β,IL-6 and IL-8 were detected. After PVT1 was knocked down,the effects of PVT1 on the proliferation and migration of gastric cancer cells were examined by cell scratch assay. RNA-pulldown combined with mass spectrometry was used to detect the protein binding to PVT1,and the result of mass spectrometry was verified by RNA-pulldown combined with Western blot. In HP-infected normal gastric epithelial cells GES-1,quantitative real-time polymerase chain reaction showed that PVT1 was significantly up-regulated (=7.160,=0.019). PVT1 was knocked down in gastric cancer cells,and then infected with HP. The expressions of inflammatory factors including TNF-α (=3.899,=0.011),IL-1β (=14.610,=0.000),and IL-8 (=6.557,=0.001) were significantly inhibited. Although PVT1 knockdown had no significant effect on the proliferation ability of gastric cancer cells,it inhibited the migration of cells. PVT1 might interact with RPS8 protein. PVT1 may act as a pro-inflammatory factor and regulate gastric cancer caused by HP infection.
Cell Line, Tumor ; Cell Movement ; Cytokines ; metabolism ; Epithelial Cells ; cytology ; microbiology ; Gene Knockdown Techniques ; Helicobacter Infections ; pathology ; Helicobacter pylori ; Humans ; Inflammation ; RNA, Long Noncoding ; genetics

(Hp) is widely disseminated in human, and Hp infection causes various gastrointestinal diseases, including gastric cancer. Different genotypes of Hp may cause different diseases, so the genotyping is important for clinical and basic research of Hp. This article introduces the methods for Hp genotyping, including multilocus sequence typing, pulsed-field gel electrophoresis, random amplified polymorphic DNA, amplified fragment length polymorphism, and whole-genome sequencing. By reviewing the application of these techniques in Hp genotyping and comparing their advantages and disadvantages, the article provides a theoretical basis for research into the pathogenesis, antibiotic resistance, and epidemiology of Hp infection.
Amplified Fragment Length Polymorphism Analysis ; Genotype ; Helicobacter Infections ; microbiology ; pathology ; Helicobacter pylori ; genetics ; Humans ; Polymerase Chain Reaction ; Research

The epithelial cytokine response, associated with reactive oxygen species (ROS), is important in Helicobacter pylori (H. pylori)-induced inflammation. H. pylori induces the production of ROS, which may be involved in the activation of mitogen-activated protein kinases (MAPK), janus kinase/signal transducers and activators of transcription (Jak/Stat), and oxidant-sensitive transcription factor, nuclear factor kappa-light-chain-enhancer of activated B cells (NF-kappaB), and thus, expression of interleukin-8 (IL-8) in gastric epithelial cells. alpha-lipoic acid, a naturally occurring thiol compound, is a potential antioxidant. It shows beneficial effects in treatment of oxidant-associated diseases including diabetes. The present study is purposed to investigate whether alpha-lipoic acid inhibits expression of inflammatory cytokine IL-8 by suppressing activation of MAPK, Jak/Stat, and NF-kappaB in H. pylori-infected gastric epithelial cells. Gastric epithelial AGS cells were pretreated with or without alpha-lipoic acid for 2 h and infected with H. pylori in a Korean isolate (HP99) at a ratio of 300:1. IL-8 mRNA expression was analyzed by RT-PCR analysis. IL-8 levels in the medium were determined by enzyme-linked immunosorbent assay. NF-kappaB-DNA binding activity was determined by electrophoretic mobility shift assay. Phospho-specific and total forms of MAPK and Jak/Stat were assessed by Western blot analysis. ROS levels were determined using dichlorofluorescein fluorescence. As a result, H. pylori induced increases in ROS levels, mRNA, and protein levels of IL-8, as well as the activation of MAPK [extracellular signal-regulated kinase 1/2 (ERK1/2), c-Jun NH2-terminal kinase 1/2 (JNK1/2), p38], Jak/Stat (Jak1/2, Stat3), and NF-kappaB in AGS cells, which was inhibited by alpha-lipoic acid. In conclusion, alpha-lipoic acid may be beneficial for prevention and/or treatment of H. pylori infection-associated gastric inflammation.
Enzyme-Linked Immunosorbent Assay ; Epithelial Cells/metabolism ; Gastric Mucosa/*drug effects/metabolism/microbiology ; Gene Expression Regulation, Bacterial ; Helicobacter Infections/immunology/*metabolism ; Helicobacter pylori/drug effects/*pathogenicity ; Humans ; Interleukin-8/genetics/*metabolism ; JNK Mitogen-Activated Protein Kinases ; Janus Kinase 1 ; Mitogen-Activated Protein Kinases/*biosynthesis ; NF-kappa B/*metabolism ; RNA, Messenger/isolation & purification/metabolism ; Reactive Oxygen Species/metabolism ; STAT3 Transcription Factor ; Stomach/metabolism/*microbiology ; Thioctic Acid/*pharmacology