Life in the human stomach: persistence strategies of the bacterial pathogen Helicobacter pylori

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.

Selective G6PDH inactivation for Helicobacter pylori eradication with transformed polysulfide

Alternative treatment for the highly prevalent Helicobacter pylori infection is imperative due to rising antibiotic resistance. We unexpectedly discovered that the anti-H. pylori component in garlic is hydrogen polysulfide (H2Sn, n⩾2), not organic polysulfides. Studies on the mechanism of action (MoA) show that H2Sn specifically inactivates H. pylori glucose-6-phosphate dehydrogenase (G6PDH) by interfering with electron transfer from glucose-6-phosphate (G6P) to nicotinamide adenine dinucleotide phosphate (NADP+). However, low H2Sn yield makes garlic derivatives hard to be a reliable donor of H2Sn to treat H. pylori infection. To address this challenge, we established a polysulfide transformation process from garlic organosulfur compounds into Fe3S4 that generates H2Sn with a 25-58 times increase in yield. Through chitosan encapsulation, we designed a gastric-adaptive H2Sn microreactor (GAPSR) that eradicates H. pylori with 250 times higher efficiency under gastric conditions. A single GAPSR achieves more rapid H. pylori eradication than combined antibiotics therapy without disturbing the gut microbiota. These findings indicate a distinct MoA transformation mediated by polysulfide as an alternative candidate to treat H. pylori infection.

Can a diet rich in Brassicaceae help control Helicobacter pylori infection? A systematic review

Introduction

Helicobacter pylori (Hp) infection is highly prevalent globally and poses a significant public health challenge due to its link with chronic gastritis, peptic ulcers, and gastric malignancies. Hp's persistence within the gastric environment, particularly in case of infection with virulent strains, triggers chronic inflammatory responses and mucosal damage. Antibiotic therapy is the primary approach for Hp eradication, but antibiotic resistance and adverse effects hinder treatment efficacy. Emerging evidence suggests that Brassicaceae-derived metabolites could serve as adjunctive therapy for Hp infection, offering potential antimicrobial and anti-inflammatory benefits.

Methods

A systematic literature review was conducted following PRISMA guidelines to assess the impact of Brassicaceae-rich diets on Hp infection control. Searches were performed in MEDLINE PubMed, Web of Science, and the Cochrane Library until 18 October 2023, without language or date restrictions. Eligible studies meeting PICOS criteria were included, encompassing populations infected with Hp or Hp-infected human cell cultures, interventions involving Brassicaceae consumption or its bioactive molecules, and outcomes related to Hp infection control, antibiotic therapy interactions, reduction of antibiotic side effects, and inflammation mitigation. Animal studies, cell line experiments, reviews unrelated to the research objectives, and studies on Hp-related gastric cancer were excluded.

Results

Available evidence indicates that Brassicaceae consumption exhibits the potential to reduce Hp colonization but achieving complete eradication of the pathogen remains challenging. Conflicting results regarding the efficacy of broccoli in Hp treatment emerge, with certain investigations suggesting limited effectiveness. Other studies point to a potential for heightened eradication rates when combined with standard triple therapy. Furthermore, promising outcomes are observed with broccoli extract supplements, indicating their role in mitigating Hp-induced gastric mucosal damage. In fact, it is noteworthy that sulforaphane and its derivatives manifest notable reductions in pro-inflammatory markers, indicative of their anti-inflammatory properties. Adverse events associated with antibiotic therapy seem unaffected by sulforaphane derivatives or probiotics. However, individual responses to these treatments vary, underscoring the unpredictability of their efficacy in ameliorating antibiotic therapy-related side effects.

Conclusion

Our systematic review highlights the potential of Brassicaceae-rich diets as adjunctive therapy for Hp infection, offering synergistic interactions with antibiotics and possibly mitigating antibiotic side effects and inflammation. Further research, particularly well-designed randomized trials, is warranted to elucidate the therapeutic efficacy and optimal utilization of Brassicaceae-derived metabolites in managing human Hp-related diseases.

Impact of Mast Cell Activation on Neurodegeneration: A Potential Role for Gut-Brain Axis and Helicobacter pylori Infection

BACKGROUND

The innate immune response aims to prevent pathogens from entering the organism and/or to facilitate pathogen clearance. Innate immune cells, such as macrophages, mast cells (MCs), natural killer cells and neutrophils, bear pattern recognition receptors and are thus able to recognize common molecular patterns, such as pathogen-associated molecular patterns (PAMPs), and damage-associated molecular patterns (DAMPs), the later occurring in the context of neuroinflammation. An inflammatory component in the pathology of otherwise "primary cerebrovascular and neurodegenerative" disease has recently been recognized and targeted as a means of therapeutic intervention. Activated MCs are multifunctional effector cells generated from hematopoietic stem cells that, together with dendritic cells, represent first-line immune defense mechanisms against pathogens and/or tissue destruction.

METHODS

This review aims to summarize evidence of MC implication in the pathogenesis of neurodegenerative diseases, namely, Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis, Huntington's disease, and multiple sclerosis.

RESULTS

In view of recent evidence that the gut-brain axis may be implicated in the pathogenesis of neurodegenerative diseases and the characterization of the neuroinflammatory component in the pathology of these diseases, this review also focuses on MCs as potential mediators in the gut-brain axis bi-directional communication and the possible role of Helicobacter pylori, a gastric pathogen known to alter the gut-brain axis homeostasis towards local and systemic pro-inflammatory responses.

CONCLUSION

As MCs and Helicobacter pylori infection may offer targets of intervention with potential therapeutic implications for neurodegenerative disease, more clinical and translational evidence is needed to elucidate this field.

Cultivation and molecular characterization of viable Helicobacter pylori from the root canal of 170 deciduous teeth of children

BACKGROUND

Helicobacter pylori is a persistent pathogen in the human stomach. However, the proposed transmission route via the oral cavity is not understood and under intense debate. While dozens of studies have shown by PCR that H. pylori DNA is frequently present in the oral cavity, data on the growth and characterization of viable H. pylori from this compartment are very scarce, and it is unclear whether the bacteria can survive in the oral cavity for longer time periods or even colonize it.

METHODS

Selective growth methods, scanning electron microscopy, urease assay, Western blotting, PCR, and gene sequencing were applied to identify and examine viable H. pylori in decayed milk teeth.

RESULTS

Here, we studied viable H. pylori in the plaque and root canals of 170 endodontically infected deciduous teeth that were extracted from 54 children. While H. pylori DNA was detected in several plaque and many root canal samples by PCR, live bacteria could only be cultivated from 28 root canals, but not from plaque. These 28 isolates have been identified as H. pylori by PCR and sequencing of vacA, cagA and htrA genes, phylogenetic analyses, protein expression of major H. pylori virulence factors, and by signal transduction events during infection of human cell lines.

CONCLUSIONS

Thus, the microaerobic environment in the root canals of endodontically infected teeth may represent a protected and transient reservoir for live H. pylori, especially in individuals with poor dental hygiene, which could serve as a potential source for re-infection of the stomach after antibiotic therapy or for transmission to other individuals.

Engineered low-pathogenic Helicobacter pylori as orally tumor immunomodulators for the stimulation of systemic immune response

Gastric cancer constitutes a malignant neoplasm characterized by heightened invasiveness, posing significant global health threat. Inspired by the analysis that gastric cancer patients with Helicobacter pylori (H. pylori) infection have higher overall survival, whether H. pylori can be used as therapeutics agent and oral drug delivery system for gastric cancer. Hence, we constructed engineered H. pylori for gastric cancer treatment. A type Ⅱ H. pylori with low pathogenicity, were conjugated with photosensitizer to develop the engineered living bacteria NIR-triggered system (Hp-Ce6). Hp-Ce6 could maintain activity in stomach acid, quickly infiltrate through mucus layer and finally migrate to tumor region owing to the cell morphology and urease of H. pylori. H. pylori, accumulated in the tumor site, severed as vaccine to activate cGAS-STING pathway, and synergistically remodel the macrophages phenotype. Upon irradiation within stomach, Hp-Ce6 directly destroyed tumor cells via photodynamic effect inherited by Ce6, companied by inducing immunogenic tumor cell death. Additionally, Hp-Ce6 exhibited excellent biosafety with fecal elimination and minimal blood absorption. This work explores the feasibility and availability of H. pylori-based oral delivery platforms for gastric tumor and further provides enlightening strategy to utilize H. pylori invariably presented in the stomach as in-situ immunomodulator to enhance antitumor efficacy.

Efficacy of B - mode and elastography ultrasound technique in the prediction of Helicobacter pylori: a prospective study

BACKGROUND

Helicobacter pylori (HP) affect nearly 50% of the world's population and can colonize the submucosal and mucosal layers of the stomach wall, causing inflammation leading to a thickening of these layers. The study aimed to evaluate the application value of transabdominal ultrasonography combined with elastography in the prediction of HP using HP Fecal Antigen Test as gold standard.

METHOD

This prospective case-control study was conducted in 174 participants classified into three groups: Group A: Symptomatic patients with thickened stomach antral and evident HP infection on fecal antigen test results, Group B: Symptomatic patients with thickened antral and no evident HP infection on fecal antigen test results, and Group C: control group of asymptomatic individuals with negative HP screening to predict the diagnostic accuracy of B-mode ultrasound and elastography in the prediction of HP pylori.

RESULTS

Positive HP patients had higher values of antral wall thickness (AWT), mucosal layer thickness (MLT), MLT/AWT ratio, SR (strain ratio), and a combination of AWT and SR: 5.57 ± 0.55 mm, 2.96 ± 0.45 mm, 0.53 ± 0.06 mm, 3.21 ± 0.43, and 8.79 ± 0.68 mm, respectively. In comparison, negative HP patients had values of 4.61 ± 0.47 mm, 2.05 ± 0.42 mm, 0.41 ± 0.08 mm, 2.51 ± 0.42 mm, and 7.13 ± 0.62 mm, respectively, and the control groups had values of 3.53 ± 0.36 mm, 1.47 ± 0.25 mm, 0.40 ± 0.06 mm, 1.81 ± 0.41, and 5.35 ± 0.55 mm, respectively (p < 0.001). The sensitivity of B-mode ultrasonography, elastography, and the combination of the two was 98%, 95.1%, and 98.4%, respectively, and the diagnostic accuracy was 98.4%, 98.3%, and 100%, respectively.

CONCLUSION

B-mode ultrasonography and elastography exhibit high discriminatory power in distinguishing symptomatic HP patients from normal individuals and differentiating + HP from - HP, with greater discriminatory power when combined both modes.

Antibiotic-Augmented Chemodynamic Therapy for Treatment of Helicobacter pylori Infection in the Dynamic Stomach Environment

Helicobacter pylori (H. pylori) is one of the main causes of peptic ulcer disease and gastric cancer. The overuse of antibiotics leads to bacterial drug resistance and disruption to the gut microbiome. Herein, a nanoparticle (TA-FeHMSN@Amox) was developed, comprising amoxicillin (Amox)-loaded iron-engineered hollow mesoporous silica as the core and a metal-polyphenol shell formed by tannic acid (TA) and Fe3+. In acidic stomach conditions, TA-FeHMSN@Amox generates bactericidal ·OH through Fenton/Fenton-like reactions of the degraded product Fe2+ and hydrogen peroxide (H2O2) at the infection site, achieving chemodynamic therapy (CDT). Moreover, released amoxicillin enhances therapeutic efficacy by impeding the self-repair of the bacterial cell wall damaged by CDT, overcoming the limitations of ineffective CDT under conditions lacking sufficient acidity and H2O2. The acidity-responsive CDT combined with reduced antibiotic usage ensures superior in vivo therapeutic efficacy and biocompatibility with intestinal flora, providing a highly potent strategy for treating H. pylori infections in the dynamic stomach environment.

Advances in Diagnostic Modalities for Helicobacter pylori Infection

Helicobacter pylori (H. pylori) infection is a widespread global health issue with a varying prevalence influenced by geography, socioeconomic status, and demographics. In the U.S., the prevalence is lower, though certain groups, such as older adults and immigrants from high-prevalence regions, show higher rates. The decrease in infection rates in developed countries is due to improved sanitation, antibiotics, and healthcare, whereas developing countries continue to experience high rates due to poor living conditions. H. pylori infection can be asymptomatic or cause symptoms like dyspepsia, abdominal pain, bloating, nausea, and loss of appetite. Pathophysiologically, H. pylori contribute to conditions such as gastritis, peptic ulcers, and gastric cancer through mechanisms including urease production and the release of virulence factors, leading to chronic inflammation and an increased cancer risk. Diagnostic methods for H. pylori have progressed significantly. Non-invasive techniques, such as serological assays, stool antigen tests, and urea breath tests, are practical and sensitive. Invasive methods, including endoscopic biopsy and molecular diagnostics, are more definitive but resource intensive. Recent advancements in diagnostic technology, including matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS), biosensor technology, and next-generation sequencing (NGS), promise improved speed, accuracy, and accessibility. These innovations are expected to enhance the detection and management of H. pylori, potentially reducing the global disease burden. This review aims to discuss these diagnostic modalities with a focus on further advances under investigation.

Optimization of Helicobacter pylori Biofilm Formation in In Vitro Conditions Mimicking Stomach

Helicobacter pylori is one of the most common bacterial pathogens worldwide and the main etiological agent of numerous gastric diseases. The frequency of multidrug resistance of H. pylori is growing and the leading factor related to this phenomenon is its ability to form biofilm. Therefore, the establishment of a proper model to study this structure is of critical need. In response to this, the aim of this original article is to validate conditions of the optimal biofilm development of H. pylori in monoculture and co-culture with a gastric cell line in media simulating human fluids. Using a set of culture-based and microscopic techniques, we proved that simulated transcellular fluid and simulated gastric fluid, when applied in appropriate concentrations, stimulate autoaggregation and biofilm formation of H. pylori. Additionally, using a co-culture system on semi-permeable membranes in media imitating the stomach environment, we were able to obtain a monolayer of a gastric cell line with H. pylori biofilm on its surface. We believe that the current model for H. pylori biofilm formation in monoculture and co-culture with gastric cells in media containing host-mimicking fluids will constitute a platform for the intensification of research on H. pylori biofilms in in vitro conditions that simulate the human body.

Synergistic effects of novel penicillin-binding protein 1A amino acid substitutions contribute to high-level amoxicillin resistance of Helicobacter pylori

The growing resistance to amoxicillin (AMX)-one of the main antibiotics used in Helicobacter pylori eradication therapy-is an increasing health concern. Several mutations of penicillin-binding protein 1A (PBP1A) are suspected of causing AMX resistance; however, only a limited set of these mutations have been experimentally explored. This study aimed to investigate four PBP1A mutations (i.e., T558S, N562H, T593A, and G595S) carried by strain KIN76, a high-level AMX-resistant clinical H. pylori isolate with an AMX minimal inhibition concentration (MIC) of 2 µg/mL. We transformed a recipient strain 26695 with the DNA containing one to four mutation allele combinations of the pbp1 gene from strain KIN76. Transformants were subjected to genomic exploration and antimicrobial susceptibility testing. The resistance was transformable, and the presence of two to four PBP1A mutations (T558S and N562H, or T593A and G595S), rather than separate single mutations, was necessary to synergistically increase the AMX MIC up to 16-fold compared with the wild-type (WT) strain 26695. An AMX binding assay of PBP1A was performed using these strains, and binding was visualized by chasing Bocillin, a fluorescent penicillin analog. This revealed that all four-mutation allele-transformed strains exhibited decreased affinity to AMX on PBP1A than the WT. Protein structure modeling indicated that functional modifications occur as a result of these amino acid substitutions. This study highlights a new synergistic AMX resistance mechanism and establishes new markers of AMX resistance in H. pylori.IMPORTANCEThe development of resistance to antibiotics, including amoxicillin, is hampering the eradication of Helicobacter pylori infection. The identification of mechanisms driving this resistance is crucial for the development of new therapeutic strategies. We have demonstrated in vitro the synergistic role of novel mutations in the pbp1 gene of H. pylori that is suspected to drive amoxicillin resistance. Also deepening our understanding of amoxicillin resistance mechanisms, this study establishes new molecular markers of amoxicillin resistance that may be useful in molecular-based antibiotic susceptibility testing approaches for clinical practice or epidemiologic investigations.

Association between Helicobacter pylori and its eradication and the development of cancer

BACKGROUND

Helicobacter pylori (H. pylori) is a gram-negative gastrointestinal pathogen that colonises the human stomach and is considered a major risk factor for gastric cancer and mucosa-associated lymphoid tissue lymphoma. Furthermore, H. pylori is a potential trigger of a wide spectrum of extragastric cancer entities, extraintestinal chronic inflammatory processes and autoimmune diseases. In the present study, we evaluated the association between H. pylori infection and its eradication with the development of subsequent gastrointestinal and non-gastrointestinal cancer.

METHODS

We identified 25 317 individuals with and 25 317 matched individuals without a diagnosis of H. pylori from the Disease Analyzer database (IQVIA). A subsequent cancer diagnosis was analysed using Kaplan-Meier and conditional Cox-regression analysis as a function of H. pylori and its eradication.

RESULTS

After 10 years of follow-up, 12.8% of the H. pylori cohort and 11.8% of the non-H. pylori cohort were diagnosed with cancer (p=0.002). Results were confirmed in regression analysis (HR: 1.11; 95% CI 1.04 to 1.18). Moreover, a non-eradicated H. pylori status (HR: 1.18; 95% CI 1.07 to 1.30) but not an eradicated H. pylori status (HR: 1.06; 95% CI 0.97 to 1.15) was associated with a subsequent diagnosis of cancer. In subgroup analyses, H. pylori eradication was negatively associated with bronchus and lung cancer (HR: 0.60; 95% CI 0.44 to 0.83).

CONCLUSION

Our data from a large outpatient cohort in Germany reveal a distinct association between H. pylori infection and the subsequent development of cancer. These data might help to identify patients at risk and support eradication strategies in the future.

Azobenzenesulfonamide Carbonic Anhydrase Inhibitors as New Weapons to Fight Helicobacter pylori: Synthesis, Bioactivity Evaluation, In Vivo Toxicity, and Computational Studies

Research into novel anti-Helicobacter pylori agents represents an important approach for the identification of new treatments for chronic gastritis and peptic ulcers, which are associated with a high risk of developing gastric carcinoma. In this respect, two series of azobenzenesulfonamides were designed, synthesized, and tested against a large panel of human and bacterial CAs to evaluate their inhibitory activity. In addition, computational studies of the novel primary benzenesulfonamides (4a-j) were performed to predict the putative binding mode to both HpCAs. Then, the antimicrobial activity versus H. pylori of the two series was also studied. The best-in-class compounds were found to be 4c and 4e among the primary azobenzenesulfonamides and 5c and 5f belonging to the secondary azobenzenesulfonamides series, showing themselves to exert a promising anti-H. pylori activity, with MIC values of 4-8 μg/mL and MBCs between 4 and 16 μg/mL. Moreover, the evaluation of their toxicity on a G. mellonella larva in vivo model indicated a safe profile for 4c,e and 5c,f. The collected results warrant considering these azobenzenesulfonamides as an interesting starting point for the development of a new class of anti-H. pylori agents.

Use of bidirectional Mendelian randomization to unveil the association of Helicobacter pylori infection and autoimmune thyroid diseases

Previous observational studies found associations between Helicobacter pylori infection and autoimmune thyroid diseases (AITDs), but the causal nature of this association is still uncertain. We investigated the causal effect of six crucial antibodies against H. pylori on AITDs using a bidirectional Mendelian randomization (MR). We found that anti-H. pylori outer membrane protein (OMP) significantly increased the risk of hyperthyroidism and Graves' disease (GD). In addition, our reverse MR analysis indicated that hyperthyroidism could increase the levels of cytotoxin-associated gene A and OMP antibodies. We also observed causal roles of GD on anti-H. pylori OMP. Our analyses indicate the mutual effects of H. pylori infection and AITDs, suggesting the existence of a gut-thyroid axis. These results also provide evidence of the bidirectional causal association between anti-H. pylori OMP with hyperthyroidism and GD, resulting in a vicious circle.

Gastric digestion of the sweet-tasting plant protein thaumatin releases bitter peptides that reduce H. pylori induced pro-inflammatory IL-17A release via the TAS2R16 bitter taste receptor

About half of the world's population is infected with the bacterium Helicobacter pylori. For colonization, the bacterium neutralizes the low gastric pH and recruits immune cells to the stomach. The immune cells secrete cytokines, i.e., the pro-inflammatory IL-17A, which directly or indirectly damage surface epithelial cells. Since (I) dietary proteins are known to be digested into bitter tasting peptides in the gastric lumen, and (II) bitter tasting compounds have been demonstrated to reduce the release of pro-inflammatory cytokines through functional involvement of bitter taste receptors (TAS2Rs), we hypothesized that the sweet-tasting plant protein thaumatin would be cleaved into anti-inflammatory bitter peptides during gastric digestion. Using immortalized human parietal cells (HGT-1 cells), we demonstrated a bitter taste receptor TAS2R16-dependent reduction of a H. pylori-evoked IL-17A release by up to 89.7 ± 21.9% (p ≤ 0.01). Functional involvement of TAS2R16 was demonstrated by the study of specific antagonists and siRNA knock-down experiments.

A deep learning-driven discovery of berberine derivatives as novel antibacterial against multidrug-resistant Helicobacter pylori

Helicobacter pylori (H. pylori) is currently recognized as the primary carcinogenic pathogen associated with gastric tumorigenesis, and its high prevalence and resistance make it difficult to tackle. A graph neural network-based deep learning model, employing different training sets of 13,638 molecules for pre-training and fine-tuning, was aided in predicting and exploring novel molecules against H. pylori. A positively predicted novel berberine derivative 8 with 3,13-disubstituted alkene exhibited a potency against all tested drug-susceptible and resistant H. pylori strains with minimum inhibitory concentrations (MICs) of 0.25-0.5 μg/mL. Pharmacokinetic studies demonstrated an ideal gastric retention of 8, with the stomach concentration significantly higher than its MIC at 24 h post dose. Oral administration of 8 and omeprazole (OPZ) showed a comparable gastric bacterial reduction (2.2-log reduction) to the triple-therapy, namely OPZ + amoxicillin (AMX) + clarithromycin (CLA) without obvious disturbance on the intestinal flora. A combination of OPZ, AMX, CLA, and 8 could further decrease the bacteria load (2.8-log reduction). More importantly, the mono-therapy of 8 exhibited comparable eradication to both triple-therapy (OPZ + AMX + CLA) and quadruple-therapy (OPZ + AMX + CLA + bismuth citrate) groups. SecA and BamD, playing a major role in outer membrane protein (OMP) transport and assembling, were identified and verified as the direct targets of 8 by employing the chemoproteomics technique. In summary, by targeting the relatively conserved OMPs transport and assembling system, 8 has the potential to be developed as a novel anti-H. pylori candidate, especially for the eradication of drug-resistant strains.

Effects of Latilactobacillus sakei LZ217 on Gastric Mucosal Colonization, Metabolic Interference, and Urease Expression in Helicobacter pylori Infection

Emerging evidence suggests differential antagonism of lactic acid-producing bacteria (LAB) to Helicobacter pylori, posing challenges to human health and food safety due to unclear mechanisms. This study assessed 21 LAB strains from various sources on H. pylori growth, urease activity, and coaggregation. Composite scoring revealed that Latilactobacillus sakei LZ217, derived from fresh milk, demonstrates strong inhibitory effects on both H. pylori growth and urease activity. L. sakei LZ217 significantly reduced H. pylori adherence of gastric cells in vitro, with inhibition ratios of 47.62%. Furthermore, in vivo results showed that L. sakei LZ217 alleviated H. pylori-induced gastric mucosa damage and inflammation in mice. Metabolomic exploration revealed metabolic perturbations in H. pylori induced by L. sakei LZ217, including reduced amino acid levels (e.g., isoleucine, leucine, glutamate, aspartate, and phenylalanine) and impaired carbohydrate and nucleotide synthesis, contributing to the suppression of ureA (28.30%), ureE (84.88%), and ureF (59.59%) expressions in H. pylori. This study underscores the efficacy of LAB against H. pylori and highlights metabolic pathways as promising targets for future interventions against H. pylori growth and colonization.

Molecular insights into the fine-tuning of pH-dependent ArsR-mediated regulation of the SabA adhesin in Helicobacter pylori

Adaptation to variations in pH is crucial for the ability of Helicobacter pylori to persist in the human stomach. The acid responsive two-component system ArsRS, constitutes the global regulon that responds to acidic conditions, but molecular details of how transcription is affected by the ArsR response regulator remains poorly understood. Using a combination of DNA-binding studies, in vitro transcription assays, and H. pylori mutants, we demonstrate that phosphorylated ArsR (ArsR-P) forms an active protein complex that binds DNA with high specificity in order to affect transcription. Our data showed that DNA topology is key for DNA binding. We found that AT-rich DNA sequences direct ArsR-P to specific sites and that DNA-bending proteins are important for the effect of ArsR-P on transcription regulation. The repression of sabA transcription is mediated by ArsR-P with the support of Hup and is affected by simple sequence repeats located upstream of the sabA promoter. Here stochastic events clearly contribute to the fine-tuning of pH-dependent gene regulation. Our results reveal important molecular aspects for how ArsR-P acts to repress transcription in response to acidic conditions. Such transcriptional control likely mediates shifts in bacterial positioning in the gastric mucus layer.

Cortactin-dependent control of Par1b-regulated epithelial cell polarity in Helicobacter infection

Cell polarity is crucial for gastric mucosal barrier integrity and mainly regulated by polarity-regulating kinase partitioning-defective 1b (Par1b). During infection, the carcinogen Helicobacter pylori hijacks Par1b via the bacterial oncoprotein CagA leading to loss of cell polarity, but the precise molecular mechanism is not fully clear. Here we discovered a novel function of the actin-binding protein cortactin in regulating Par1b, which forms a complex with cortactin and the tight junction protein zona occludens-1 (ZO-1). We found that serine phosphorylation at S405/418 and the SH3 domain of cortactin are important for its interaction with both Par1b and ZO-1. Cortactin knockout cells displayed disturbed Par1b cellular localization and exhibited morphological abnormalities that largely compromised transepithelial electrical resistance, epithelial cell polarity, and apical microvilli. H. pylori infection promoted cortactin/Par1b/ZO-1 abnormal interactions in the tight junctions in a CagA-dependent manner. Infection of human gastric organoid-derived mucosoids supported these observations. We therefore hypothesize that CagA disrupts gastric epithelial cell polarity by hijacking cortactin, and thus Par1b and ZO-1, suggesting a new signaling pathway for the development of gastric cancer by Helicobacter.

Probiotic mixture in patients after Helicobacter pylori eradication: a real-life experience

BACKGROUND

Eradication for Helicobacter pylori usually induces digestive dysbiosis that, in turn, elicits symptoms. Consequently, probiotic supplementation may counterbalance the disturbed microbiota after this procedure. So, probiotics may restore microbiota homeostasis quickly relieve complaints.

METHODS

The current study evaluated the efficacy and safety of Abivisor®, a food supplement containing Lacticaseibacillus rhamnosus LR06 (3 billion living cells), Lactiplantibacillus pentosus LPS01(100 million living cells), Lactiplantibacillus plantarum LP01 (1 billion living cells), and N-acetyl cysteine (60 mg). Patients were randomized into two groups (2:1). Group A took one stick/daily for 60 days after eradication. Group B was considered as control. Patients were evaluated at baseline (T0) and after 15 (T1), 30 (T2), and 60 (T3) days. The severity of digestive symptoms was measured by patients using a Visual Analog Scale. The percentage of patients with each symptom was also evaluated.

RESULTS

Abivisor® has significantly and progressively diminished intestinal symptoms' presence and severity at T1, T2, and even more at T3. Accordingly, the percentage of symptomatic patients diminished more rapidly and significantly in group A than in B. All patients well tolerated the food supplement.

CONCLUSIONS

The present study suggests that Abivisor® may be an effective and safe therapeutic option for managing patients undergoing H. pylori eradication.

Helicobacter pylori disrupts gastric mucosal homeostasis by stimulating macrophages to secrete CCL3

BACKGROUND

Helicobacter pylori (H. pylori) is the predominant etiological agent of gastritis and disrupts the integrity of the gastric mucosal barrier through various pathogenic mechanisms. After H. pylori invades the gastric mucosa, it interacts with immune cells in the lamina propria. Macrophages are central players in the inflammatory response, and H. pylori stimulates them to secrete a variety of inflammatory factors, leading to the chronic damage of the gastric mucosa. Therefore, the study aims to explore the mechanism of gastric mucosal injury caused by inflammatory factors secreted by macrophages, which may provide a new mechanism for the development of H. pylori-related gastritis.

METHODS

The expression and secretion of CCL3 from H. pylori infected macrophages were detected by RT-qPCR, Western blot and ELISA. The effect of H. pylori-infected macrophage culture medium and CCL3 on gastric epithelial cells tight junctions were analyzed by Western blot, immunofluorescence and transepithelial electrical resistance. EdU and apoptotic flow cytometry assays were used to detect cell proliferation and apoptosis levels. Dual-luciferase reporter assays and chromatin immunoprecipitation assays were used to study CCL3 transcription factors. Finally, gastric mucosal tissue inflammation and CCL3 expression were analyzed by hematoxylin and eosin staining and immunohistochemistry.

RESULTS

After H. pylori infection, CCL3 expressed and secreted from macrophages were increased. H. pylori-infected macrophage culture medium and CCL3 disrupted gastric epithelial cells tight junctions, while CCL3 neutralizing antibody and receptor inhibitor of CCL3 improved the disruption of tight junctions between cells. In addition, H. pylori-infected macrophage culture medium and CCL3 recombinant proteins stimulated P38 phosphorylation, and P38 phosphorylation inhibitor improved the disruption of tight junctions between cells. Besides, it was identified that STAT1 was a transcription factor of CCL3 and H. pylori stimulated macrophage to secret CCL3 through the JAK1-STAT1 pathway. Finally, after mice were injected with murine CCL3 recombinant protein, the gastric mucosal injury and inflammation were aggravated, and the phosphorylation level of P38 was increased.

CONCLUSIONS

In summary, our findings demonstrate that H. pylori infection stimulates macrophages to secrete CCL3 via the JAK1-STAT1 pathway. Subsequently, CCL3 damages gastric epithelial tight junctions through the phosphorylation of P38. This may be a novel mechanism of gastric mucosal injury in H. pylori-associated gastritis.

Helicobacter pylori secretary Proteins-Induced oxidative stress and its role in NLRP3 inflammasome activation

Helicobacter pylori-associated stomach infection is a leading cause of gastric ulcer and related cancer. H. pylori modulates the functions of infiltrated immune cells to survive the killing by reactive oxygen and nitrogen species (ROS and RNS) produced by these cells. Uncontrolled immune responses further produce excess ROS and RNS which lead to mucosal damage. The persistent oxidative stress is a major cause of gastric cancer. H. pylori regulates nicotinamide adenine dinucleotide phosphate (NADPH) oxidases (NOXs), nitric oxide synthase 2 (NOS2), and polyamines to control ROS and RNS release through lesser-known mechanisms. ROS and RNS produced by these pathways differentiate macrophages and T cells from protective to inflammatory phenotype. Pathogens-associated molecular patterns (PAMPs) induced ROS activates nuclear oligomerization domain (NOD), leucine rich repeats (LRR) and pyrin domain-containing protein 3 (NLRP3) inflammasome for the release of pro-inflammatory cytokines. This study evaluates the role of H. pylori secreted concentrated proteins (HPSCP) related oxidative stress role in NLRP3 inflammasome activation and macrophage differentiation. To perceive the role of ROS/RNS, THP-1 and AGS cells were treated with 10 μM diphenyleneiodonium (DPI), 50 μM salicyl hydroxamic acid (SHX), 5 μM Carbonyl cyanide-4-(trifluoromethoxy) phenylhydrazone (FCCP), which are specific inhibitors of NADPH oxidase (NOX), Myeloperoxidase (MPO), and mitochondrial oxidative phosphorylation respectively. Cells were also treated with 10 μM of NOS2 inhibitor l-NMMA and 10 μM of N-acetyl cysteine (NAC), a free radical scavenger·H2O2 (100 μM) treated and untreated cells were used as positive controls and negative control respectively. The expression of gp91phox (NOX2), NOS2, NLRP3, CD86 and CD163 was analyzed through fluorescent microscopy. THP-1 macrophages growth was unaffected whereas the gastric epithelial AGS cells proliferated in response to higher concentration of HPSCP. ROS and myeloperoxidase (MPO) level increased in THP-1 cells and nitric oxide (NO) and lipid peroxidation significantly decreased in AGS cells. gp91phox expression was unchanged, whereas NOS2 and NLRP3 downregulated in response to HPSCP, but increased after inhibition of NO, ROS and MPO in THP-1 cells. HPSCP upregulated the expression of M1 and M2 macrophage markers, CD86 and CD163 respectively, which was decreased after the inhibition of ROS. This study concludes that there are multiple pathways which are generating ROS during H. pylori infection which further regulates other cellular processes. NO is closely associated with MPO and inhibition of NLRP3 inflammasome. The low levels of NO and MPO regulates gastrointestinal tract homeostasis and overcomes the inflammatory response of NLRP3. The ROS also plays crucial role in macrophage polarization hence alter the immune responses duing H. pylori pathogenesis.

The emerging tumor microbe microenvironment: From delineation to multidisciplinary approach-based interventions

Intratumoral microbiota has become research hotspots, and emerges as a non-negligent new component of tumor microenvironments (TME), due to its powerful influence on tumor initiation, metastasis, immunosurveillance and prognosis despite in low-biomass. The accumulations of microbes, and their related components and metabolites within tumor tissues, endow TME with additional pluralistic features which are distinct from the conventional one. Therefore, it's definitely necessary to comprehensively delineate the sophisticated landscapes of tumor microbe microenvironment, as well as their functions and related underlying mechanisms. Herein, in this review, we focused on the fields of tumor microbe microenvironment, including the heterogeneity of intratumor microbiota in different types of tumors, the controversial roles of intratumoral microbiota, the basic features of tumor microbe microenvironment (i.e., pathogen-associated molecular patterns (PAMPs), typical microbial metabolites, autophagy, inflammation, multi-faceted immunomodulation and chemoresistance), as well as the multidisciplinary approach-based intervention of tumor microbiome for cancer therapy by applying wild-type or engineered live microbes, microbiota metabolites, antibiotics, synthetic biology and rationally designed biomaterials. We hope our work will provide valuable insight to deeply understand the interplay of cancer-immune-microbial, and facilitate the development of microbes-based tumor-specific treatments.

Structural diversity and clustering of bacterial flagellar outer domains

Supercoiled flagellar filaments function as mechanical propellers within the bacterial flagellum complex, playing a crucial role in motility. Flagellin, the building block of the filament, features a conserved inner D0/D1 core domain across different bacterial species. In contrast, approximately half of the flagellins possess additional, highly divergent outer domain(s), suggesting varied functional potential. In this study, we elucidate atomic structures of flagellar filaments from three distinct bacterial species: Cupriavidus gilardii , Stenotrophomonas maltophilia , and Geovibrio thiophilus . Our findings reveal that the flagella from the facultative anaerobic G. thiophilus possesses a significantly more negatively charged surface, potentially enabling adhesion to positively charged minerals. Furthermore, we analyzed all AlphaFold predicted structures for annotated bacterial flagellins, categorizing the flagellin outer domains into 682 structural clusters. This classification provides insights into the prevalence and experimental verification of these outer domains. Remarkably, two of the flagellar structures reported herein belong to a previously unexplored cluster, indicating new opportunities on the study of the functional diversity of flagellar outer domains. Our findings underscore the complexity of bacterial flagellins and open up possibilities for future studies into their varied roles beyond motility.

Unraveling the crystal structure of the HpaA adhesin: insights into cell adhesion function and epitope localization of a Helicobacter pylori vaccine candidate

Helicobacter pylori is a bacterium that exhibits strict host restriction to humans and non-human primates, and the bacterium is widely acknowledged as a significant etiological factor in the development of chronic gastritis, peptic ulcers, and gastric cancers. The pathogenic potential of this organism lies in its adeptness at colonizing the gastric mucosa, which is facilitated by a diverse repertoire of virulence factors, including adhesins that promote the attachment of the bacteria to the gastric epithelium. Among these adhesins, HpaA stands out due to its conserved nature and pivotal role in establishing H. pylori colonization. Moreover, this lipoprotein holds promise as an antigen for the development of effective H. pylori vaccines, thus attracting considerable attention for in-depth investigations into its molecular function and identification of binding determinants. Here, we present the elucidation of the crystallographic structure of HpaA at 2.9 Å resolution. The folding adopts an elongated protein shape, which is distinctive to the Helicobacteraceae family, and features an apical domain extension that plays a critical role in the cell-adhesion activity on gastric epithelial cells. Our study also demonstrates the ability of HpaA to induce TNF-α expression in macrophages, highlighting a novel role as an immunoregulatory effector promoting the pro-inflammatory response in vitro. These findings not only contribute to a deeper comprehension of the multifaceted role of HpaA in H. pylori pathogenesis but also establish a fundamental basis for the design and development of structure-based derivatives, aimed at enhancing the efficacy of H. pylori vaccines.

IMPORTANCE

Helicobacter pylori is a bacterium that can cause chronic gastritis, peptic ulcers, and gastric cancers. The bacterium adheres to the lining of the stomach using proteins called adhesins. One of these proteins, HpaA, is particularly important for H. pylori colonization and is considered a promising vaccine candidate against H. pylori infections. In this work, we determined the atomic structure of HpaA, identifying a characteristic protein fold to the Helicobacter family and delineating specific amino acids that are crucial to support the attachment to the gastric cells. Additionally, we discovered that HpaA can trigger the production of TNF-α, a proinflammatory molecule, in macrophages. These findings provide valuable insights into how H. pylori causes disease and suggest that HpaA has a dual role in both attachment and immune activation. This knowledge could contribute to the development of improved vaccine strategies for preventing H. pylori infections.

WITHDRAWN: PIRES2-EGFP/CTB-UreI vaccination activated a mixed Th1/Th2/Th17 immune system defense towards Helicobacter pylori infection in the BALB/c mice model

This article has been withdrawn at the request of the Editor. The Publisher apologizes for any inconvenience this may cause. The full Elsevier Policy on Article Withdrawal can be found at https://www.elsevier.com/about/policies/article-withdrawal. The data presented in the manuscript was deemed severely flawed after appearing online as an Article in Press. The scientific community raised concerns about the methodology (including but not limited to major technical issues) used in the study and the subsequent conclusions drawn from the presented experiments. After careful investigation, the Vaccine editorial office concluded that the data in the publication was indeed severely flawed and that the concerns raised by the scientific community were valid. Therefore, the journal editors decided to withdraw the article and sincerely apologize for any inconvenience caused.

High-throughput detection allied with machine learning for precise monitoring of significant serum metabolic changes in Helicobacter pylori infection

High-throughput detection of large-scale samples is the foundation for rapidly accessing massive metabolic data in precision medicine. Machine learning is a powerful tool for uncovering valuable information hidden within massive data. In this work, we achieved the extraction of a single fingerprinting of 1 μL serum within 5 s through a high-throughput detection platform based on functionalized nanoparticles. We quickly obtained over a thousand serum metabolic fingerprintings (SMFs) including those of individuals with Helicobacter pylori (HP) infection. Combining four classical machine learning models and enrichment analysis, we attempted to extract and confirm useful information behind these SMFs. Based on all fingerprint signals, all four models achieved area under the curve (AUC) values of 0.983-1. In particular, orthogonal partial least squares discriminant analysis (OPLS-DA) model obtained value of 1 in both the discovery and validation sets. Fortunately, we identified six significant metabolic features, all of which can greatly contribute to the monitoring of HP infection, with AUC values ranging from 0.906 to 0.985. The combination of these six significant metabolic features can enable the precise monitoring of HP infection in serum, with over 95 % of accuracy, specificity and sensitivity. The OPLS-DA model displayed optimal performance and the corresponding scatter plot visualized the clear distinction between HP and HC. Interestingly, they exhibit a consistent reduction trend compared to healthy controls, prompting us to explore the possible metabolic pathways and potential mechanism. This work demonstrates the potential alliance between high-throughput detection and machine learning, advancing their application in precision medicine.

Remodeling of the gastric environment in Helicobacter pylori-induced atrophic gastritis

Helicobacter pylori colonization of the human stomach is a strong risk factor for gastric cancer. To investigate H. pylori-induced gastric molecular alterations, we used a Mongolian gerbil model of gastric carcinogenesis. Histologic evaluation revealed varying levels of atrophic gastritis (a premalignant condition characterized by parietal and chief cell loss) in H. pylori-infected animals, and transcriptional profiling revealed a loss of markers for these cell types. We then assessed the spatial distribution and relative abundance of proteins in the gastric tissues using imaging mass spectrometry and liquid chromatography with tandem mass spectrometry. We detected striking differences in the protein content of corpus and antrum tissues. Four hundred ninety-two proteins were preferentially localized to the corpus in uninfected animals. The abundance of 91 of these proteins was reduced in H. pylori-infected corpus tissues exhibiting atrophic gastritis compared with infected corpus tissues exhibiting non-atrophic gastritis or uninfected corpus tissues; these included numerous proteins with metabolic functions. Fifty proteins localized to the corpus in uninfected animals were diffusely delocalized throughout the stomach in infected tissues with atrophic gastritis; these included numerous proteins with roles in protein processing. The corresponding alterations were not detected in animals infected with a H. pylori ∆cagT mutant (lacking Cag type IV secretion system activity). These results indicate that H. pylori can cause loss of proteins normally localized to the gastric corpus as well as diffuse delocalization of corpus-specific proteins, resulting in marked changes in the normal gastric molecular partitioning into distinct corpus and antrum regions.IMPORTANCEA normal stomach is organized into distinct regions known as the corpus and antrum, which have different functions, cell types, and gland architectures. Previous studies have primarily used histologic methods to differentiate these regions and detect H. pylori-induced alterations leading to stomach cancer. In this study, we investigated H. pylori-induced gastric molecular alterations in a Mongolian gerbil model of carcinogenesis. We report the detection of numerous proteins that are preferentially localized to the gastric corpus but not the antrum in a normal stomach. We show that stomachs with H. pylori-induced atrophic gastritis (a precancerous condition characterized by the loss of specialized cell types) exhibit marked changes in the abundance and localization of proteins normally localized to the gastric corpus. These results provide new insights into H. pylori-induced gastric molecular alterations that are associated with the development of stomach cancer.

Immune evasion by proteolytic shedding of natural killer group 2, member D ligands in Helicobacter pylori infection

Background

Helicobacter pylori (H. pylori) uses various strategies that attenuate mucosal immunity to ensure its persistence in the stomach. We recently found evidence that H. pylori might modulate the natural killer group 2, member 2 (NKG2D) system. The NKG2D receptor and its ligands are a major activation system of natural killer and cytotoxic T cells, which are important for mucosal immunity and tumor immunosurveillance. The NKG2D system allows recognition and elimination of infected and transformed cells, however viruses and cancers often subvert its activation. Here we aimed to identify a potential evasion of the NKG2D system in H. pylori infection.

Methods

We analyzed expression of NKG2D system genes in gastric tissues of H. pylori gastritis and gastric cancer patients, and performed cell-culture based infection experiments using H. pylori isogenic mutants and epithelial and NK cell lines.

Results

In biopsies of H. pylori gastritis patients, NKG2D receptor expression was reduced while NKG2D ligands accumulated in the lamina propria, suggesting NKG2D evasion. In vitro, H. pylori induced the transcription and proteolytic shedding of NKG2D ligands in stomach epithelial cells, and these effects were associated with specific H. pylori virulence factors. The H. pylori-driven release of soluble NKG2D ligands reduced the immunogenic visibility of infected cells and attenuated the cytotoxic activity of effector immune cells, specifically the anti-tumor activity of NK cells.

Conclusion

H. pylori manipulates the NKG2D system. This so far unrecognized strategy of immune evasion by H. pylori could potentially facilitate chronic bacterial persistence and might also promote stomach cancer development by allowing transformed cells to escape immune recognition and grow unimpeded to overt malignancy.

Helicobacter pylori: A Contemporary Perspective on Pathogenesis, Diagnosis and Treatment Strategies

Helicobacter pylori (H. pylori) is a Gram-negative bacterium that colonizes the gastric mucosa and is associated with various gastrointestinal disorders. H. pylori is a pervasive pathogen, infecting nearly 50% of the world's population, and presents a substantial concern due to its link with gastric cancer, ranking as the third most common cause of global cancer-related mortality. This review article provides an updated and comprehensive overview of the current understanding of H. pylori infection, focusing on its pathogenesis, diagnosis, and treatment strategies. The intricate mechanisms underlying its pathogenesis, including the virulence factors and host interactions, are discussed in detail. The diagnostic methods, ranging from the traditional techniques to the advanced molecular approaches, are explored, highlighting their strengths and limitations. The evolving landscape of treatment strategies, including antibiotic regimens and emerging therapeutic approaches, is thoroughly examined. Through a critical synthesis of the recent research findings, this article offers valuable insights into the contemporary knowledge of Helicobacter pylori infection, guiding both clinicians and researchers toward effective management and future directions in combating this global health challenge.

Engineering Heterogeneous Tumor Models for Biomedical Applications

Tumor tissue engineering holds great promise for replicating the physiological and behavioral characteristics of tumors in vitro. Advances in this field have led to new opportunities for studying the tumor microenvironment and exploring potential anti-cancer therapeutics. However, the main obstacle to the widespread adoption of tumor models is the poor understanding and insufficient reconstruction of tumor heterogeneity. In this review, the current progress of engineering heterogeneous tumor models is discussed. First, the major components of tumor heterogeneity are summarized, which encompasses various signaling pathways, cell proliferations, and spatial configurations. Then, contemporary approaches are elucidated in tumor engineering that are guided by fundamental principles of tumor biology, and the potential of a bottom-up approach in tumor engineering is highlighted. Additionally, the characterization approaches and biomedical applications of tumor models are discussed, emphasizing the significant role of engineered tumor models in scientific research and clinical trials. Lastly, the challenges of heterogeneous tumor models in promoting oncology research and tumor therapy are described and key directions for future research are provided.

Future Nanotechnology-Based Strategies for Improved Management of Helicobacter pylori Infection

Helicobacter pylori (H. pylori) is a recalcitrant pathogen, which can cause gastric disorders. During the past decades, polypharmacy-based regimens, such as triple and quadruple therapies have been widely used against H. pylori. However, polyantibiotic therapies can disturb the host gastric/gut microbiota and lead to antibiotic resistance. Thus, simpler but more effective approaches should be developed. Here, some recent advances in nanostructured drug delivery systems to treat H. pylori infection are summarized. Also, for the first time, a drug release paradigm is proposed to prevent H. pylori antibiotic resistance along with an IVIVC model in order to connect the drug release profile with a reduction in bacterial colony counts. Then, local delivery systems including mucoadhesive, mucopenetrating, and cytoadhesive nanobiomaterials are discussed in the battle against H. pylori infection. Afterward, engineered delivery platforms including polymer-coated nanoemulsions and polymer-coated nanoliposomes are poposed. These bioinspired platforms can contain an antimicrobial agent enclosed within smart multifunctional nanoformulations. These bioplatforms can prevent the development of antibiotic resistance, as well as specifically killing H. pylori with no or only slight negative effects on the host gastrointestinal microbiota. Finally, the essential checkpoints that should be passed to confirm the potential effectiveness of anti-H. pylori nanosystems are discussed.

Recent Developments in Metallic Degradable Micromotors for Biomedical and Environmental Remediation Applications

Synthetic micromotor has gained substantial attention in biomedicine and environmental remediation. Metal-based degradable micromotor composed of magnesium (Mg), zinc (Zn), and iron (Fe) have promise due to their nontoxic fuel-free propulsion, favorable biocompatibility, and safe excretion of degradation products Recent advances in degradable metallic micromotor have shown their fast movement in complex biological media, efficient cargo delivery and favorable biocompatibility. A noteworthy number of degradable metal-based micromotors employ bubble propulsion, utilizing water as fuel to generate hydrogen bubbles. This novel feature has projected degradable metallic micromotors for active in vivo drug delivery applications. In addition, understanding the degradation mechanism of these micromotors is also a key parameter for their design and performance. Its propulsion efficiency and life span govern the overall performance of a degradable metallic micromotor. Here we review the design and recent advancements of metallic degradable micromotors. Furthermore, we describe the controlled degradation, efficient in vivo drug delivery, and built-in acid neutralization capabilities of degradable micromotors with versatile biomedical applications. Moreover, we discuss micromotors' efficacy in detecting and destroying environmental pollutants. Finally, we address the limitations and future research directions of degradable metallic micromotors.

Helicobacter pylori induces a novel form of innate immune memory via accumulation of NF-кB proteins

Helicobacter pylori is a widespread Gram-negative pathogen involved in a variety of gastrointestinal diseases, including gastritis, ulceration, mucosa-associated lymphoid tissue (MALT) lymphoma and gastric cancer. Immune responses aimed at eradication of H. pylori often prove futile, and paradoxically play a crucial role in the degeneration of epithelial integrity and disease progression. We have previously shown that H. pylori infection of primary human monocytes increases their potential to respond to subsequent bacterial stimuli - a process that may be involved in the generation of exaggerated, yet ineffective immune responses directed against the pathogen. In this study, we show that H. pylori-induced monocyte priming is not a common feature of Gram-negative bacteria, as Acinetobacter lwoffii induces tolerance to subsequent Escherichia coli lipopolysaccharide (LPS) challenge. Although the increased reactivity of H. pylori-infected monocytes seems to be specific to H. pylori, it appears to be independent of its virulence factors Cag pathogenicity island (CagPAI), cytotoxin associated gene A (CagA), vacuolating toxin A (VacA) and γ-glutamyl transferase (γ-GT). Utilizing whole-cell proteomics complemented with biochemical signaling studies, we show that H. pylori infection of monocytes induces a unique proteomic signature compared to other pro-inflammatory priming stimuli, namely LPS and the pathobiont A. lwoffii. Contrary to these tolerance-inducing stimuli, H. pylori priming leads to accumulation of NF-кB proteins, including p65/RelA, and thus to the acquisition of a monocyte phenotype more responsive to subsequent LPS challenge. The plasticity of pro-inflammatory responses based on abundance and availability of intracellular signaling molecules may be a heretofore underappreciated form of regulating innate immune memory as well as a novel facet of the pathobiology induced by H. pylori.

Optical detection using CRISPR-Cas12a of Helicobacter pylori for veterinary applications

Helicobacter pylori (H. pylori) is a zoonotic gastric microorganism capable of efficient interspecies transmission. Domesticated companion animals, particularly dogs and cats, serve as natural reservoirs for H. pylori. This phenomenon facilitates the extensive dissemination of H. pylori among households with pets. Hence, the prompt and precise identification of H. pylori in companion animals holds paramount importance for the well-being of both animals and their owners. With the assistance of Multienzyme Isothermal Rapid Amplification (MIRA) and CRISPR-Cas12a system, we successfully crafted a highly adaptable optical detection platform for H. pylori. Three sensor systems with corresponding visual interpretations were proposed. This study demonstrated a rapid turnaround time of approximately 45 min from DNA extraction to the result display. Moreover, this platform topped germiculture and real-time PCR in terms of sensitivity or efficiency in clinical diagnoses of 66 samples. This platform possesses significant potential as a versatile approach and represents the premiere application of CRISPR for the non-invasive detection of H. pylori in companion animals, thereby mitigating the dissemination of H. pylori among household members.

Practice guidelines for the management of Helicobacter pylori infection: The Saudi H. pylori Working Group recommendations

The eradication rates for Helicobacter pylori globally are decreasing with a dramatic increase in the prevalence of antibiotic resistant bacteria all over the world, including Saudi Arabia. There is no current consensus on the management of H. pylori in Saudi Arabia. The Saudi Gastroenterology Association developed these practice guidelines after reviewing the local and regional studies on the management of H. pylori. The aim was to establish recommendations to guide healthcare providers in managing H. pylori in Saudi Arabia. Experts in the areas of H. pylori management and microbiology were invited to write these guidelines. A literature search was performed, and all authors participated in writing and reviewing the guidelines. In addition, international guidelines and consensus reports were reviewed to bridge the gap in knowledge when local and regional data were unavailable. There is limited local data on treatment of H. pylori. The rate of clarithromycin and metronidazole resistance is high; therefore, standard triple therapy for 10-14 days is no longer recommended in the treatment of H. pylori unless antimicrobial susceptibility testing was performed. Based on the available data, bismuth quadruple therapy for 10-14 days is considered the best first-line and second-line therapy. Culture and antimicrobial susceptibility testing should be considered following two treatment failures. These recommendations are intended to provide the most relevant evidence-based guidelines for the management of H. pylori infection in Saudi Arabia. The working group recommends further studies to explore more therapeutic options to eradicate H. pylori.

The SlyD metallochaperone targets iron-sulfur biogenesis pathways and the TCA cycle

IMPORTANCE

Correct folding of proteins represents a crucial step for their functions. Among the chaperones that control protein folding, the ubiquitous PPIases catalyze the cis/trans-isomerization of peptidyl-prolyl bonds. Only few protein targets of PPIases have been reported in bacteria. To fill this knowledge gap, we performed a large-scale two-hybrid screen to search for targets of the Escherichia coli and Helicobacter pylori SlyD PPIase-metallochaperone. SlyD from both organisms interacts with enzymes (i) containing metal cofactors, (ii) from the central metabolism tricarboxylic acid (TCA) cycle, and (iii) involved in the formation of the essential and ancestral Fe-S cluster cofactor. E. coli and H. pylori ∆slyD mutants present similar phenotypes of diminished susceptibility to antibiotics and to oxidative stress. In H. pylori, measurements of the intracellular ATP content, proton motive force, and activity of TCA cycle proteins suggest that SlyD regulates TCA cycle enzymes by controlling the formation of their indispensable Fe-S clusters.

Erlotinib-containing benzenesulfonamides as anti-Helicobacter pylori agents through carbonic anhydrase inhibition

Aim: Development of dual-acting antibacterial agents containing Erlotinib, a recognized EGFR inhibitor used as an anticancer agent, with differently spaced benzenesulfonamide moieties known to bind and inhibit Helicobacter pylori carbonic anhydrase (HpCA) or the antiviral Zidovudine. Methods & materials: Through rational design, ten derivatives were obtained via a straightforward synthesis including a click chemistry reaction. Inhibitory activity against a panel of pathogenic carbonic anhydrases and antibacterial susceptibility of H. pylori ATCC 43504 were assessed. Docking studies on α-carbonic anhydrase enzymes and EGFR were conducted to gain insight into the binding mode of these compounds. Results & conclusion: Some compounds proved to be strong inhibitors of HpCA and showed good anti-H. pylori activity. Computational studies on the targeted enzymes shed light on the interaction hotspots.

Association of Helicobacter pylori Positivity With Risk of Disease and Mortality

INTRODUCTION

Helicobacter pylori colonizes the human stomach. Infection causes chronic gastritis and increases the risk of gastroduodenal ulcer and gastric cancer. Its chronic colonization in the stomach triggers aberrant epithelial and inflammatory signals that are also associated with systemic alterations.

METHODS

Using a PheWAS analysis in more than 8,000 participants in the community-based UK Biobank, we explored the association of H. pylori positivity with gastric and extragastric disease and mortality in a European country.

RESULTS

Along with well-established gastric diseases, we dominantly found overrepresented cardiovascular, respiratory, and metabolic disorders. Using multivariate analysis, the overall mortality of H. pylori -positive participants was not altered, while the respiratory and Coronovirus 2019-associated mortality increased. Lipidomic analysis for H. pylori -positive participants revealed a dyslipidemic profile with reduced high-density lipoprotein cholesterol and omega-3 fatty acids, which may represent a causative link between infection, systemic inflammation, and disease.

DISCUSSION

Our study of H. pylori positivity demonstrates that it plays an organ- and disease entity-specific role in the development of human disease and highlights the importance of further research into the systemic effects of H. pylori infection.

A single-nucleotide polymorphism in Helicobacter pylori promotes gastric cancer development

Single-nucleotide polymorphisms (SNPs) in various human genes are key factors in carcinogenesis. However, whether SNPs in bacterial pathogens are similarly crucial in cancer development is unknown. Here, we analyzed 1,043 genomes of the stomach pathogen Helicobacter pylori and pinpointed a SNP in the serine protease HtrA (position serine/leucine 171) that significantly correlates with gastric cancer. Our functional studies reveal that the 171S-to-171L mutation triggers HtrA trimer formation and enhances proteolytic activity and cleavage of epithelial junction proteins occludin and tumor-suppressor E-cadherin. 171L-type HtrA, but not 171S-HtrA-possessing H. pylori, inflicts severe epithelial damage, enhances injection of oncoprotein CagA into epithelial cells, increases NF-κB-mediated inflammation and cell proliferation through nuclear accumulation of β-catenin, and promotes host DNA double-strand breaks, collectively triggering malignant changes. These findings highlight the 171S/L HtrA mutation as a unique bacterial cancer-associated SNP and as a potential biomarker for risk predictions in H. pylori infections.

The TLR/MyD88 signalling cascade in inflammation and gastric cancer: the immune regulatory network of Helicobacter pylori

Helicobacter pylori-induced chronic gastritis represents a well-established risk factor for gastric cancer (GC). However, the mechanism by which chronic inflammation caused by H. pylori induces the development of GC is unclear. H. pylori can influence host cell signalling pathways to induce gastric disease development and mediate cancer promotion and progression. Toll-like receptors (TLRs), as pattern recognition receptors (PRRs), play a key role in the gastrointestinal innate immune response, and their signalling has been implicated in the pathogenesis of an increasing number of inflammation-associated cancers. The core adapter myeloid differentiation factor-88 (MyD88) is shared by most TLRs and functions primarily in H. pylori-triggered innate immune signalling. MyD88 is envisioned as a potential target for the regulation of immune responses and is involved in the regulation of tumourigenesis in a variety of cancer models. In recent years, the TLR/MyD88 signalling pathway has received increasing attention for its role in regulating innate and adaptive immune responses, inducing inflammatory activation and promoting tumour formation. In addition, TLR/MyD88 signalling can manipulate the expression of infiltrating immune cells and various cytokines in the tumour microenvironment (TME). In this review, we discuss the pathogenetic regulatory mechanisms of the TLR/MyD88 signalling cascade pathway and its downstream molecules in H. pylori infection-induced-associated GC. The focus is to elucidate the immunomolecular mechanisms of pathogen recognition and innate immune system activation of H. pylori in the TME of inflammation-associated GC. Ultimately, this study will provide insight into the mechanism of H. pylori-induced chronic inflammation-induced GC development and provide thoughts for GC prevention and treatment strategies.

Helicobacter pylori in children: think before you kill the bug!

Since the discovery of Helicobacter pylori (H. pylori) as the causative organism for gastric and duodenal ulcers four decades ago and subsequent recognition as class 1 gastric carcinogen, countless numbers of studies have been conducted and papers published, on the efficacy of various management strategies to eradicate the infection. In adults, a global consensus by the experts in the field concluded that H. pylori gastritis is an infectious disease and requires treatment irrespective of the presence or absence of symptoms due to the potential for serious complication like peptic ulcer disease and gastric neoplasia. However, although more than half the world's population harbors H. pylori, these serious complications occur only in a small minority of the infected population, even less so in childhood. More importantly, there is accumulating evidence for beneficial role of H. pylori against many chronic health conditions, from several epidemiological and laboratory studies. No doubt, eradication therapy is indicated in children with H. pylori-related peptic ulcer disease. Even though the pediatric guidelines from various learned societies recommend against a "test and treat" strategy, this is not always adhered to. With the accumulating evidence of the possible beneficial role of H. pylori, it is time to pause and think, are we causing more harm than good by eradicating H. pylori in every child who has this bug?

Anthocyanin-rich black carrot (Daucus carota ssp. sativus var. atrorubens Alef.) and red cabbage (Brassica oleracea) extracts incorporated biosensor for colorimetric detection of Helicobacter pylori with color image processing

In this work, we developed novel colorimetric biosensors consisting of anthocyanin-rich either black carrot (Daucus carota ssp. sativus var. atrorubens Alef.) or red cabbage (Brassica oleracea) extracts for rapid, sensitive, and economic detection of Helicobacter pylori (H. pylori). We comparatively prepared two test solutions as biosensors including anthocyanin-rich black carrot extract (Anth@BCE) and red cabbage extract (Anth@RCE), both of which fixed to pH 2.5 and investigated their colorimetric responses based on electronic structure and electron density of anthocyanins. We successfully used anthocyanin-rich BCE and RCE as natural pH indicators in detection of H. pylori and introduced their advantages like non-toxicity, easy accessibility, and high stability compared to synthetic indicators. The BCE and RCE tests gave the best color change in the presence of 103 CFU/mL (at 60 min) and 104 CFU/mL (at 75 min) H. pylori suspensions prepared in an artificial gastric fluid. The limit of detection was down to 10 CFU/mL for RCE and BCE tests by increasing incubation time (≥ 5 h). We further made an additional study that color differences in the colorimetric responses observed by naked eyes were supported by digital image processing with RGB (Red Green Blue) and Delta-E (ΔE) analysis. It is confirmed that results evaluated by naked eyes and digital image processing are well consistent with each other. These findings proposed that these colorimetric tests can be implemented to pH dependent detection of various microorganisms and can be effectively transferred from laboratory work to clinics in the near future.

Helicobacter pylori attachment-blocking antibodies protect against duodenal ulcer disease

The majority of the world population carry the gastric pathogen Helicobacter pylori. Fortunately, most individuals experience only low-grade or no symptoms, but in many cases the chronic inflammatory infection develops into severe gastric disease, including duodenal ulcer disease and gastric cancer. Here we report on a protective mechanism where H. pylori attachment and accompanying chronic mucosal inflammation can be reduced by antibodies that are present in a vast majority of H. pylori carriers. These antibodies block binding of the H. pylori attachment protein BabA by mimicking BabA's binding to the ABO blood group glycans in the gastric mucosa. However, many individuals demonstrate low titers of BabA blocking antibodies, which is associated with an increased risk for duodenal ulceration, suggesting a role for these antibodies in preventing gastric disease.

Organoids: Construction and Application in Gastric Cancer

Gastric organoids are biological models constructed in vitro using stem cell culture and 3D cell culture techniques, which are the latest research hotspots. The proliferation of stem cells in vitro is the key to gastric organoid models, making the cell subsets within the models more similar to in vivo tissues. Meanwhile, the 3D culture technology also provides a more suitable microenvironment for the cells. Therefore, the gastric organoid models can largely restore the growth condition of cells in terms of morphology and function in vivo. As the most classic organoid models, patient-derived organoids use the patient's own tissues for in vitro culture. This kind of model is responsive to the 'disease information' of a specific patient and has great effect on evaluating the strategies of individualized treatment. Herein, we review the current literature on the establishment of organoid cultures, and also explore organoid translational applications.

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.

The cytosolic DNA sensor AIM2 promotes Helicobacter-induced gastric pathology via the inflammasome

Helicobacter pylori (H. pylori) infection can trigger chronic gastric inflammation perpetuated by overactivation of the innate immune system, leading to a cascade of precancerous lesions culminating in gastric cancer. However, key regulators of innate immunity that promote H. pylori-induced gastric pathology remain ill-defined. The innate immune cytosolic DNA sensor absent in melanoma 2 (AIM2) contributes to the pathogenesis of numerous autoimmune and chronic inflammatory diseases, as well as cancers including gastric cancer. We therefore investigated whether AIM2 contributed to the pathogenesis of Helicobacter-induced gastric disease. Here, we reveal that AIM2 messenger RNA and protein expression levels are elevated in H. pylori-positive versus H. pylori-negative human gastric biopsies. Similarly, chronic Helicobacter felis infection in wild-type mice augmented Aim2 gene expression levels compared with uninfected controls. Notably, gastric inflammation and hyperplasia were less severe in H. felis-infected Aim2-/- versus wild-type mice, evidenced by reductions in gastric immune cell infiltrates, mucosal thickness and proinflammatory cytokine and chemokine release. In addition, H. felis-driven proliferation and apoptosis in both gastric epithelial and immune cells were largely attenuated in Aim2-/- stomachs. These observations in Aim2-/- mouse stomachs correlated with decreased levels of inflammasome activity (caspase-1 cleavage) and the mature inflammasome effector cytokine, interleukin-1β. Taken together, this work uncovers a pathogenic role for the AIM2 inflammasome in Helicobacter-induced gastric disease, and furthers our understanding of the host immune response to a common pathogen and the complex and varying roles of AIM2 at different stages of cancerous and precancerous gastric disease.

Gastric microbiota: an emerging player in gastric cancer

Gastric cancer (GC) is a common cancer worldwide with a high mortality rate. Many microbial factors influence GC, of which the most widely accepted one is Helicobacter pylori (H. pylori) infection. H. pylori causes inflammation, immune reactions and activation of multiple signaling pathways, leading to acid deficiency, epithelial atrophy, dysplasia and ultimately GC. It has been proved that complex microbial populations exist in the human stomach. H. pylori can affect the abundance and diversity of other bacteria. The interactions among gastric microbiota are collectively implicated in the onset of GC. Certain intervention strategies may regulate gastric homeostasis and mitigate gastric disorders. Probiotics, dietary fiber, and microbiota transplantation can potentially restore healthy microbiota. In this review, we elucidate the specific role of the gastric microbiota in GC and hope these data can facilitate the development of effective prevention and therapeutic approaches for GC.

Regulatory B cells (Bregs) in Helicobacter pylori chronic infection

BACKGROUND

Helicobacter pylori (H. pylori) infection is linked with a wide variety of diseases and was reported in more than half of the world's population. Chronic H. pylori infection and its final clinical outcome depend mainly on the bacterial virulence factors and its ability to manipulate and adapt to human immune responses. Bregs blood levels have been correlated with increased bacterial load and infection chronicity, especially Gram-negative bacterial infection. This study aimed to identify prevalence and virulence factors of chronic H. pylori infection among symptomatic Egyptian patients and to examine its possible correlation to levels of regulatory B cells (Bregs) in blood.

MATERIALS AND METHODS

Gastric biopsies and blood samples from each of 113 adult patients, who underwent upper endoscopy, were examined for the detection of H. pylori by culture and PCR methods. Conventional PCR was used to determine various virulent genes prevalence and association to clinical outcome. Flow cytometry was used to evaluate Bregs levels.

RESULTS

Helicobacter pylori prevalence was 49.1% (55/112). Regarding virulence genes incidence, flaA gene was detected in 73% (40/55), vir B11 in 56.4% (31/55), hopZ1 in 34.5% (19/55), hopZ2 in 89% (49/55), babA2 in 52.7% (29/55), dupA jhp917 in 61.8% (34/55), vacA m1/m2 in 70.9% (39/55), and vacA s1/s2 in 69% (38/55) strains. Bregs levels were significantly lower in H. pylori-infected patients (p = 0.013), while total leukocyte count (TLC) showed no significant differences.

CONCLUSION

Helicobacter pylori infection prevalence was almost 49%, and the infection was found to be related to inflammatory conditions as gastritis and ulcers rather than malignant transformations. Also, we found that CD24⁺ CD38⁺ B cells were downregulated in H. pylori-infected patients.

Linking dysbiosis to precancerous stomach through inflammation: Deeper than and beyond imaging

Upper gastrointestinal endoscopy is considered the gold standard for gastric lesions detection and surveillance, but it is still associated with a non-negligible rate of missing conditions. In the Era of Personalized Medicine, biomarkers could be the key to overcome missed lesions or to better predict recurrence, pushing the frontier of endoscopy to functional endoscopy. In the last decade, microbiota in gastric cancer has been extensively explored, with gastric carcinogenesis being associated with progressive dysbiosis. Helicobacter pylori infection has been considered the main causative agent of gastritis due to its interference in disrupting the acidic environment of the stomach through inflammatory mediators. Thus, does inflammation bridge the gap between gastric dysbiosis and the gastric carcinogenesis cascade and could the microbiota-inflammation axis-derived biomarkers be the answer to the unmet challenge of functional upper endoscopy? To address this question, in this review, the available evidence on the role of gastric dysbiosis and chronic inflammation in precancerous conditions of the stomach is summarized, particularly targeting the nuclear factor-κB (NF-κB), toll-like receptors (TLRs) and cyclooxygenase-2 (COX-2) pathways. Additionally, the potential of liquid biopsies as a non-invasive source and the clinical utility of studied biomarkers is also explored. Overall, and although most studies offer a mechanistic perspective linking a strong proinflammatory Th1 cell response associated with, but not limited to, chronic infection with Helicobacter pylori, promising data recently published highlights not only the diagnostic value of microbial biomarkers but also the potential of gastric juice as a liquid biopsy pushing forward the concept of functional endoscopy and personalized care in gastric cancer early diagnosis and surveillance.