Helicobacter pylori-induced matrix metallopeptidase-10 promotes gastric bacterial colonization and gastritis

The effect of immunotherapy PD-1 blockade on acute bone cancer pain: Insights from transcriptomic and microbiomic profiling

INTRODUCTION

The skeletal system ranks as the third most common site for cancer metastasis, often leading to pain with nociceptive and neuropathic features. Programmed cell death protein 1 (PD-1)-targeting therapeutic antibodies offer effective cancer treatment but can cause treatment-related acute pain. Understanding the mechanisms of this pain and identifying potential interventions is still a challenge.

METHODS

A murine model of bone cancer pain was established using Lewis lung carcinoma (LLC) cells, followed by intravenous administration of nivolumab, a human anti-PD-1 monoclonal antibody. Pain thresholds were measured, and micro-CT images of the skeletal system were obtained. High-throughput sequencing of the spinal cord/colon transcriptome during the acute phase of bone cancer pain and gut microbiota analysis at the end of the treatment were performed. Immunofluorescence staining and western blot experiments assessed spinal cord microglia activation and acute pain-associated molecules.

RESULTS

PD-1 inhibition with nivolumab protected against bone degradation initiated by LLC cell administration but consistently induced acute pain during nivolumab treatment. Spinal cord and colon transcriptomics revealed an immunopathological pattern during tumor progression and the acute pain phase, with notable changes in interleukin and S100 gene families. Gut microbiota analysis post-immunotherapy showed a decline in beneficial bacteria associated with short-chain fatty acid (SCFA) production. Activation of spinal cord microglia and enhanced glycolytic metabolism were confirmed as key factors in inducing acute pain following immunotherapy.

CONCLUSIONS

This study reveals that nivolumab induces acute pain by activating microglia and enhancing glycolytic metabolism in the treatment of bone cancer and uncovers connections between transcriptomic changes, gut microbiota, and acute pain following immune checkpoint blockade (ICB) treatment. It offers novel insights into the relationship between immune checkpoint blockade therapies and pain management.

Helicobacter pylori triggers inflammation and oncogenic transformation by perturbing the immune microenvironment

The immune microenvironment plays a critical regulatory role in the pathogenesis of Helicobacter pylori (H. pylori). Understanding the mechanisms that drive the transition from chronic inflammation to cancer may provide new insights for early detection of gastric cancer. Although chronic inflammation is frequent in precancerous gastric conditions, the monitoring function of the inflammatory microenvironment in the progression from H. pylori-induced chronic inflammation to gastric cancer remains unclear. This literature review summarizes significant findings on how H. pylori triggers inflammatory responses and facilitates cancer development through the immune microenvironment. Furthermore, the implications for future research and clinical applications are also addressed. The review is divided into four main sections: inflammatory response and immune evasion mechanisms induced by H. pylori, immune dysregulation associated with gastric cancer, therapeutic implications, and future perspectives on H. pylori-induced gastric carcinogenesis with a focus on the immune microenvironment.

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.

Helicobacter pylori-Induced Angiopoietin-Like 4 Promotes Gastric Bacterial Colonization and Gastritis

Helicobacter pylori infection is characterized as progressive processes of bacterial persistence and chronic gastritis with features of infiltration of mononuclear cells more than granulocytes in gastric mucosa. Angiopoietin-like 4 (ANGPTL4) is considered a double-edged sword in inflammation-associated diseases, but its function and clinical relevance in H. pylori-associated pathology are unknown. Here, we demonstrate both pro-colonization and pro-inflammation roles of ANGPTL4 in H. pylori infection. Increased ANGPTL4 in the infected gastric mucosa was produced from gastric epithelial cells (GECs) synergistically induced by H. pylori and IL-17A in a cagA-dependent manner. Human gastric ANGPTL4 correlated with H. pylori colonization and the severity of gastritis, and mouse ANGPTL4 from non-bone marrow-derived cells promoted bacteria colonization and inflammation. Importantly, H. pylori colonization and inflammation were attenuated in Il17a -/-, Angptl4 -/-, and Il17a -/- Angptl4 -/- mice. Mechanistically, ANGPTL4 bound to integrin αV (ITGAV) on GECs to suppress CXCL1 production by inhibiting ERK, leading to decreased gastric influx of neutrophils, thereby promoting H. pylori colonization; ANGPTL4 also bound to ITGAV on monocytes to promote CCL5 production by activating PI3K-AKT-NF-κB, resulting in increased gastric influx of regulatory CD4+ T cells (Tregs) via CCL5-CCR4-dependent migration. In turn, ANGPTL4 induced Treg proliferation by binding to ITGAV to activate PI3K-AKT-NF-κB, promoting H. pylori-associated gastritis. Overall, we propose a model in which ANGPTL4 collectively ensures H. pylori persistence and promotes gastritis. Efforts to inhibit ANGPTL4-associated pathway may prove valuable strategies in treating H. pylori infection.

Clinical evaluation of a real-time PCR assay for diagnosis of Helicobacter pylori infection and antibiotic resistance

OBJECTIVES

Helicobacter pylori (H. pylori) is a globally prevalent bacterium that increases the risk of developing various gastrointestinal diseases, including gastric adenocarcinoma. This study aimed to evaluate the performances of real-time PCR assay in detecting H. pylori infection, as well as clarithromycin and levofloxacin resistance, in both stool and gastric biopsy specimens.

METHODS

Stool and gastric biopsy specimens were collected from patients within one to three days post-hospitalization. All patients were analyzed for H. pylori infection and resistance to clarithromycin and levofloxacin using a real-time PCR based molecular assay.

RESULTS

169 patients (83 males) with a mean age of 43.6±13.1 years were included in the study. The prevalence of H. pylori was 89.9% (152/169) in stool and 90.5% (153/169) in gastric biopsy samples. The molecular diagnostics employed in this study exhibited a sensitivity of 99.3% and a specificity of 100%, resulting in a diagnostic accuracy rate of 99.6%. Resistance to clarithromycin was 36.1% (61/169) in stool and 44.4% (75/169) in gastric biopsy samples. The molecular tests for clarithromycin resistance demonstrated a sensitivity of 96.8% and a specificity of 86.8%, with an overall diagnostic accuracy of 90.5%. Furthermore, resistance to levofloxacin was 22.5% (38/169) and 26.6% (45/169) in stool and gastric biopsy samples, respectively. The molecular test demonstrated a sensitivity of 80.9% and a specificity of 94.3%, resulting in a diagnostic accuracy of 90.5%.

CONCLUSION

The implementation of real-time PCR-based screening for H. pylori infection and resistance to clarithromycin and levofloxacin in the stool may enhance the success rate of eradication therapy.

An all-in-one therapeutic platform for the treatment of resistant Helicobacter pylori infection

Helicobacter pylori (H. pylori) infection is a major cause of gastric diseases. Currently, bismuth-based quadruple therapy is widely adopted for eradicating H. pylori infection. However, this first-line strategy faces several challenges such as drug resistance, intestinal dysbacteriosis, and patients' poor compliance. To overcome these problems, an all-in-one therapeutic platform (CLA-Bi-ZnO2@Lipo) that composed of liposomes loading clarithromycin (CLA), Bi, and ZnO2 hybrid nanoparticles was developed for eradicating multidrug-resistant (MDR) H. pylori. The in vitro and in vivo results showed that CLA-Bi-ZnO2@Lipo could target the infection-induced inflammatory mucosa through liposome mediated nanoparticle-tissue surface charge interaction and quickly respond to the gastric acid environment to release CLA, Bi3+, Zn2+, and H2O2. By oral administration per day, the acid triggered decomposition of CLA-Bi-ZnO2@Lipo could significantly increase intragastric pH to 6 within 30 min; The released CLA, Zn2+, and H2O2 further exerted synergistical anti-bacterial effects in which a ∼2 order higher efficacy in reducing MDR H. pylori burden was achieved in comparison with standard quadruple therapy (p < 0.05); The released Zn2+ and Bi3+ could also alleviate mucosal inflammation. Most importantly, the CLA-Bi-ZnO2@Lipo exhibited superior biosafety and nearly no side effects on intestinal flora. Overall, this study developed a highly integrated and safe anti-MDR H. pylori agent which had great potential to be used as an alternative treatment for MDR H. pylori eradication.

A Natural Peptide from A Traditional Chinese Medicine Has the Potential to Treat Chronic Atrophic Gastritis by Activating Gastric Stem Cells

Chronic atrophic gastritis (AG) is initiated mainly by Helicobacter pylori infection, which may progress to stomach cancer following the Correa's cascade. The current treatment regimen is H. pylori eradication, yet evidence is lacking that this treatment is effective on later stages of AG especially gastric gland atrophy. Here, using AG mouse model, patient samples, gastric organoids, and lineage tracing, this study unraveled gastric stem cell (GSC) defect as a crucial pathogenic factor in AG in mouse and human. Moreover, a natural peptide is isolated from a traditional Chinese medicine that activated GSCs to regenerate gastric epithelia in experimental AG models and revitalized the atrophic gastric organoids derived from patients. It is further shown that the peptide exerts its functions by stabilizing the EGF-EGFR complex and specifically activating the downstream ERK and Stat1 signaling. Overall, these findings advance the understanding of AG pathogenesis and open a new avenue for AG treatment.

Strategies of Helicobacter pylori in evading host innate and adaptive immunity: insights and prospects for therapeutic targeting

Helicobacter pylori (H. pylori) is the predominant pathogen causing chronic gastric mucosal infections globally. During the period from 2011 to 2022, the global prevalence of H. pylori infection was estimated at 43.1%, while in China, it was slightly higher at approximately 44.2%. Persistent colonization by H. pylori can lead to gastritis, peptic ulcers, and malignancies such as mucosa-associated lymphoid tissue (MALT) lymphomas and gastric adenocarcinomas. Despite eliciting robust immune responses from the host, H. pylori thrives in the gastric mucosa by modulating host immunity, particularly by altering the functions of innate and adaptive immune cells, and dampening inflammatory responses adverse to its survival, posing challenges to clinical management. The interaction between H. pylori and host immune defenses is intricate, involving evasion of host recognition by modifying surface molecules, manipulating macrophage functionality, and modulating T cell responses to evade immune surveillance. This review analyzes the immunopathogenic and immune evasion mechanisms of H. pylori, underscoring the importance of identifying new therapeutic targets and developing effective treatment strategies, and discusses how the development of vaccines against H. pylori offers new hope for eradicating such infections.

Tubulointerstitial nephritis antigen-like 1 is a novel matricellular protein that promotes gastric bacterial colonization and gastritis in the setting of Helicobacter pylori infection

The interaction between the gastric epithelium and immune cells plays key roles in H. pylori-associated pathology. Here, we demonstrate a procolonization and proinflammatory role of tubulointerstitial nephritis antigen-like 1 (TINAGL1), a newly discovered matricellular protein, in H. pylori infection. Increased TINAGL1 production by gastric epithelial cells (GECs) in the infected gastric mucosa was synergistically induced by H. pylori and IL-1β via the ERK-SP1 pathway in a cagA-dependent manner. Elevated human gastric TINAGL1 correlated with H. pylori colonization and the severity of gastritis, and mouse TINAGL1 derived from non-bone marrow-derived cells promoted bacterial colonization and inflammation. Importantly, H. pylori colonization and inflammation were attenuated in Tinagl1-/- and Tinagl1ΔGEC mice and were increased in mice injected with mouse TINAGL1. Mechanistically, TINAGL1 suppressed CCL21 expression and promoted CCL2 production in GECs by directly binding to integrin α5β1 to inhibit ERK and activate the NF-κB pathway, respectively, which not only led to decreased gastric influx of moDCs via CCL21-CCR7-dependent migration and, as a direct consequence, reduced the bacterial clearance capacity of the H. pylori-specific Th1 response, thereby promoting H. pylori colonization, but also resulted in increased gastric influx of Ly6Chigh monocytes via CCL2-CCR2-dependent migration. In turn, TINAGL1 induced the production of the proinflammatory protein S100A11 by Ly6Chigh monocytes, promoting H. pylori-associated gastritis. In summary, we identified a model in which TINAGL1 collectively ensures H. pylori persistence and promotes gastritis.

Human alveolar macrophage response to Mycobacterium tuberculosis: immune characteristics underlying large inter-individual variability

Background

Mycobacterium tuberculosis (M.tb), the causative bacterium of tuberculosis (TB), establishes residence and grows in human alveolar macrophages (AMs). Inter-individual variation in M.tb-human AM interactions can indicate TB risk and the efficacy of therapies and vaccines; however, we currently lack an understanding of the gene and protein expression programs that dictate this variation in the lungs.

Results

Herein, we systematically analyze interactions of a virulent M.tb strain H37Rv with freshly isolated human AMs from 28 healthy adult donors, measuring host RNA expression and secreted candidate proteins associated with TB pathogenesis over 72h. A large set of genes possessing highly variable inter-individual expression levels are differentially expressed in response to M.tb infection. Eigengene modules link M.tb growth rate with host transcriptional and protein profiles at 24 and 72h. Systems analysis of differential RNA and protein expression identifies a robust network with IL1B, STAT1, and IDO1 as hub genes associated with M.tb growth. RNA time profiles document stimulation towards an M1-type macrophage gene expression followed by emergence of an M2-type profile. Finally, we replicate these results in a cohort from a TB-endemic region, finding a substantial portion of significant differentially expressed genes overlapping between studies.

Conclusions

We observe large inter-individual differences in bacterial uptake and growth, with tenfold variation in M.tb load by 72h.The fine-scale resolution of this work enables the identification of genes and gene networks associated with early M.tb growth dynamics in defined donor clusters, an important step in developing potential biological indicators of individual susceptibility to M.tb infection and response to therapies.

A Review of Gut Microbiota-Derived Metabolites in Tumor Progression and Cancer Therapy

Gut microbiota-derived metabolites are key hubs connecting the gut microbiome and cancer progression, primarily by remodeling the tumor microenvironment and regulating key signaling pathways in cancer cells and multiple immune cells. The use of microbial metabolites in radiotherapy and chemotherapy mitigates the severe side effects from treatment and improves the efficacy of treatment. Immunotherapy combined with microbial metabolites effectively activates the immune system to kill tumors and overcomes drug resistance. Consequently, various novel strategies have been developed to modulate microbial metabolites. Manipulation of genes involved in microbial metabolism using synthetic biology approaches directly affects levels of microbial metabolites, while fecal microbial transplantation and phage strategies affect levels of microbial metabolites by altering the composition of the microbiome. However, some microbial metabolites harbor paradoxical functions depending on the context (e.g., type of cancer). Furthermore, the metabolic effects of microorganisms on certain anticancer drugs such as irinotecan and gemcitabine, render the drugs ineffective or exacerbate their adverse effects. Therefore, a personalized and comprehensive consideration of the patient's condition is required when employing microbial metabolites to treat cancer. The purpose of this review is to summarize the correlation between gut microbiota-derived metabolites and cancer, and to provide fresh ideas for future scientific research.

Gut Microbiota in Colorectal Cancer: Biological Role and Therapeutic Opportunities

Colorectal cancer (CRC) is the second-leading cause of cancer-related deaths worldwide. While CRC is thought to be an interplay between genetic and environmental factors, several lines of evidence suggest the involvement of gut microbiota in promoting inflammation and tumor progression. Gut microbiota refer to the ~40 trillion microorganisms that inhabit the human gut. Advances in next-generation sequencing technologies and metagenomics have provided new insights into the gut microbial ecology and have helped in linking gut microbiota to CRC. Many studies carried out in humans and animal models have emphasized the role of certain gut bacteria, such as Fusobacterium nucleatum, enterotoxigenic Bacteroides fragilis, and colibactin-producing Escherichia coli, in the onset and progression of CRC. Metagenomic studies have opened up new avenues for the application of gut microbiota in the diagnosis, prevention, and treatment of CRC. This review article summarizes the role of gut microbiota in CRC development and its use as a biomarker to predict the disease and its potential therapeutic applications.

Current Knowledge of Th22 Cell and IL-22 Functions in Infectious Diseases

T helper 22 (Th22) cells, a newly defined CD4+ T-cell lineage, are characterized by their distinct cytokine profile, which primarily consists of IL-13, IL-22 and TNF-α. Th22 cells express a wide spectrum of chemokine receptors, such as CCR4, CCR6 and CCR10. The main effector molecule secreted by Th22 cells is IL-22, a member of the IL-10 family, which acts by binding to IL-22R and triggering a complex downstream signaling system. Th22 cells and IL-22 have been found to play variable roles in human immunity. In preventing the progression of infections such as HIV and influenza, Th22/IL-22 exhibited protective anti-inflammatory characteristics, and their deleterious proinflammatory activities have been demonstrated to exacerbate other illnesses, including hepatitis B and Helicobacter pylori infection. Herein, we review the current understanding of Th22 cells, including their definition, differentiation and mechanisms, and the effect of Th22/IL-22 on human infectious diseases. According to studies on Th22 cells, Th22/IL-22 may be a promising therapeutic target and an effective treatment strategy for various infections.

Immune Biology and Persistence of Helicobacter pylori in Gastric Diseases

Helicobacter pylori is a prevalent pathogen, which affects more than 40% of the global population. It colonizes the human stomach and persists in its host for several decades or even a lifetime, if left untreated. The persistent infection has been linked to various gastric diseases, including gastritis, peptic ulcers, and an increased risk for gastric cancer. H. pylori infection triggers a strong immune response directed against the bacterium associated with the infiltration of innate phagocytotic immune cells and the induction of a Th1/Th17 response. Even though certain immune cells seem to be capable of controlling the infection, the host is unable to eliminate the bacteria as H. pylori has developed remarkable immune evasion strategies. The bacterium avoids its killing through innate recognition mechanisms and manipulates gastric epithelial cells and immune cells to support its persistence. This chapter focuses on the innate and adaptive immune response induced by H. pylori infection, and immune evasion strategies employed by the bacterium to enable persistent infection.

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

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

Breastfeeding Is Associated with Lower Likelihood of Helicobacter Pylori Colonization in Babies, Based on a Prospective USA Maternal-Infant Cohort

BACKGROUND

Mother-to-child transmission of Helicobacter pylori (H. pylori) is the primary source of intrafamilial spread in early childhood in regions of high H. pylori prevalence. However, early-in-life H. pylori colonization and associated protective or risk factors have not been fully evaluated in lower prevalence regions, such as the USA.

AIMS

Therefore, from a well-characterized prospective US cohort, we selected women who provided fecal samples during pregnancy and had paired fecal samples from their babies up to 24 months postpartum. We evaluated maternal and baby factors associated with likelihood of H. pylori colonization in the babies. Fecal antigen testing was used to determine H. pylori status. We also evaluated the association between maternal breastmilk cytokines and H. pylori colonization in breastfed babies.

RESULTS

Among included mother-baby pairs (n = 66), H. pylori prevalence was 31.8% in mothers and 19.7% in their babies. Dominant breastfeeding (adjusted odds ratio [aOR] 0.17, 95% CI 0.03-0.98) and maternal IBD (aOR 0.05, 95% CI 0.01-0.27) were associated with significantly lower likelihood of H. pylori colonization among babies; no other clinical factors were associated with H. pylori colonization in the babies. Matrix metalloproteinase-10 (MMP-10) and tumor necrosis factor-related activation-induced cytokine expression were significantly higher in breastmilk of mothers with H. pylori positive vs negative babies.

CONCLUSIONS

Consistent with data from high H. pylori prevalence regions, our findings suggest dominant breastfeeding may protect against early H. pylori colonization. Downregulation of pro-inflammatory cytokines such as MMP-10 may be relevant in mediating this protection among breastfed babies, but more data are needed.

The prebiotic and anti-fatigue effects of hyaluronan

Hyaluronan (HA) is a mucopolysaccharide that naturally exists in all living organisms as the main component of the extracellular matrix. Over the last 30 years, HA has been used as the main ingredient in cosmetic products, eye drops, and medicinal products. It is also taken orally as a health supplement. However, the physiological effect of the ingested HA is not clear. In the current study, the interaction between HA and gut microbiota, and the potential prebiotic effects were investigated. HA was used to treat the C57BL/6 mice for 15 consecutive days, then fecal genomic DNA was extracted from fecal samples for 16S rRNA amplicon sequencing. The results showed that HA could significantly change the composition of gut microbiota (GM), e.g., increased the relative abundance of beneficial bacteria, including short-chain fatty acids (SCFAs)-producing bacteria and xylan/cellulose-degrading bacteria, whereas decreased the relative abundance of potential pathogens including sulfate-reducing bacteria (SRB), inflammation and cancer-related bacteria. The rotarod test was used to evaluate the anti-fatigue effects of HA in C57BL/6 mice. The results showed that HA could lengthen the mice's retention time on the accelerating rotarod. HA increased the concentration of glycogen and superoxide dismutase (SOD) in mice's muscle and liver, whereas decreased the serum concentration of malondialdehyde (MDA). Moreover, the metabolic products of Desulfovibrio vulgaris (MPDV), the model SRB bacteria, showed cytotoxic effects on H9c2 cardiomyocytes in a dosage-dependent manner. MPDV also caused mitochondrial damage by inducing mitochondrial fragmentation, depolarization, and powerless ATP production. Taken together, we show that HA possesses significant prebiotic and anti-fatigue effects in C57BL/6 mice.

Astaxanthin Inhibits Matrix Metalloproteinase Expression by Suppressing PI3K/AKT/mTOR Activation in Helicobacter pylori-Infected Gastric Epithelial Cells

Helicobacter pylori (H. pylori) increases production of reactive oxygen species (ROS) and activates signaling pathways associated with gastric cell invasion, which are mediated by matrix metalloproteinases (MMPs). We previously demonstrated that H. pylori activated mitogen-activated protein kinase (MAPK) and increased expression of MMP-10 in gastric epithelial cells. MMPs degrade the extracellular matrix, enhancing tumor invasion and cancer progression. The signaling pathway of phosphatidylinositol 3-kinase (PI3K)/serine/threonine protein kinase B (AKT)/mammalian target of rapamycin (mTOR) is associated with MMP expression. ROS activates PIK3/AKT/mTOR signaling in cancer. Astaxanthin, a xanthophyll carotenoid, shows antioxidant activity by reducing ROS levels in gastric epithelial cells infected with H. pylori. This study aimed to determine whether astaxanthin inhibits MMP expression, cell invasion, and migration by reducing the PI3K/AKT/mTOR signaling in H. pylori-infected gastric epithelial AGS cells. H. pylori induced PIK3/AKT/mTOR and NF-κB activation, decreased IκBα, and induced MMP (MMP-7 and -10) expression, the invasive phenotype, and migration in AGS cells. Astaxanthin suppressed these H. pylori-induced alterations in AGS cells. Specific inhibitors of PI3K, AKT, and mTOR reversed the H. pylori-stimulated NF-κB activation and decreased IκBα levels in the cells. In conclusion, astaxanthin suppressed MMP expression, cell invasion, and migration via inhibition of PI3K/AKT/mTOR/NF-κB signaling in H. pylori-stimulated gastric epithelial AGS cells.

Single-cell transcriptomics reveals immune dysregulation mediated by IL-17A in initiation of chronic lung injuries upon real-ambient particulate matter exposure

Background

Long-term exposure to fine particulate matter (PM_2.5) increases susceptibility to chronic respiratory diseases, including inflammation and interstitial fibrosis. However, the regulatory mechanisms by which the immune response mediates the initiation of pulmonary fibrosis has yet to be fully characterized. This study aimed to illustrate the interplay between different cell clusters and key pathways in triggering chronic lung injuries in mice following PM exposure.

Results

Six-week-old C57BL/6J male mice were exposed to PM or filtered air for 16 weeks in a real-ambient PM exposure system in Shijiazhuang, China. The transcriptional profiles of whole lung cells following sub-chronic PM exposure were characterized by analysis of single-cell transcriptomics. The IL-17A knockout (IL-17A^−/−) mouse model was utilized to determine whether the IL-17 signaling pathway mediated immune dysregulation in PM-induced chronic lung injuries. After 16-week PM exposure, chronic lung injuries with excessive collagen deposition and increased fibroblasts, neutrophils, and monocytes were noted concurrent with a decreased number of major classes of immune cells. Single-cell analysis showed that activation of the IL-17 signaling pathway was involved in the progression of pulmonary fibrosis upon sub-chronic PM exposure. Depletion of IL-17A led to significant decline in chronic lung injuries, which was mainly triggered by reduced recruitment of myeloid-derived suppressor cells (MDSCs) and downregulation of TGF-β.

Conclusion

These novel findings demonstrate that immunosuppression via the IL-17A pathway plays a critical role in the initiation of chronic lung injuries upon sub-chronic PM exposure.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12989-022-00483-w.

Helicobacter pylori infection induces stem cell-like properties in Correa cascade of gastric cancer

Gastric cancer (GC) is the fourth leading cause of cancer-related death. Its poor prognosis is attributed to unclear pathogenesis. Currently, the most widely accepted model for elucidating the mechanism of GC is the Correa cascade, which covers several histological lesions of the gastric mucosa. GC stem cells (CSCs) are crucial for oncogenesis in the Correa cascade and GC progression. As Helicobacter pylori (H. pylori) is the etiological factor in the Correa cascade, growing evidence suggests that enhancement of gastric stem cell-like properties and increase in CSCs correlate with H. pylori infection. In this paper, we review recent studies that present pathogenic mechanisms by which H. pylori induces gastric stem cell-like properties and CSCs, which may supplement the existing Correa model of GC. First, the dysfunction of developmental signaling pathways associated with H. pylori infection leads to the enhancement of gastric stemness. Second, H. pylori infection promotes alteration of the gastric mucosal microenvironment. In addition, epithelial-mesenchymal transition (EMT) may contribute to H. pylori-induced gastric stemness. Taken together, understanding these pathogeneses will provide potential therapeutic targets for the treatment of CSCs and malignant GC in H. pylori induced-Correa cascade of GC.

The Efficacy of Cancer Immunotherapies Is Compromised by Helicobacter pylori Infection

Helicobacter pylori infects the gastric mucosa of a large number of humans. Although asymptomatic in the vast majority of cases, H pylori infection can lead to the development of peptic ulcers gastric adenocarcinoma and mucosa-associated lymphoid tissue (MALT) lymphoma. Using a variety of mechanisms, H pylori locally suppresses the function of the host immune system to establish chronic infection. Systemic immunomodulation has been observed in both clinical and pre-clinical studies, which have demonstrated that H pylori infection is associated with reduced incidence of inflammatory diseases, such as asthma and Crohn’s disease. The introduction of immunotherapies in the arsenal of anti-cancer drugs has revealed a new facet of H pylori-induced immune suppression. In this review, we will describe the intimate interactions between H pylori and its host, and formulate hypothtyeses describing the detrimental impact of H pylori infection on the efficacy of cancer immunotherapies.

Proteolytic Landscapes in Gastric Pathology and Cancerogenesis

Gastric cancer is a leading cause of cancer-related death, and a large proportion of cases are inseparably linked to infections with the bacterial pathogen and type I carcinogen Helicobacter pylori. The development of gastric cancer follows a cascade of transformative tissue events in an inflammatory environment. Proteases of host origin as well as H. pylori-derived proteases contribute to disease progression at every stage, from chronic gastritis to gastric cancer. In the present article, we discuss the importance of (metallo-)proteases in colonization, epithelial inflammation, and barrier disruption in tissue transformation, deregulation of cell proliferation and cell death, as well as tumor metastasis and neoangiogenesis. Proteases of the matrix metalloproteinase (MMP) and a disintegrin and metalloproteinase domain-containing protein (ADAM) families, caspases, calpain, and the H. pylori proteases HtrA, Hp1012, and Hp0169 cleave substrates including extracellular matrix molecules, chemokines, and cytokines, as well as their cognate receptors, and thus shape the pathogenic microenvironment. This review aims to summarize the current understanding of how proteases contribute to disease progression in the gastric compartment.

Matrix Metalloproteinase-10 in Kidney Injury Repair and Disease

Matrix metalloproteinase-10 (MMP-10) is a zinc-dependent endopeptidase with the ability to degrade a broad spectrum of extracellular matrices and other protein substrates. The expression of MMP-10 is induced in acute kidney injury (AKI) and chronic kidney disease (CKD), as well as in renal cell carcinoma (RCC). During the different stages of kidney injury, MMP-10 may exert distinct functions by cleaving various bioactive substrates including heparin-binding epidermal growth factor (HB-EGF), zonula occludens-1 (ZO-1), and pro-MMP-1, -7, -8, -9, -10, -13. Functionally, MMP-10 is reno-protective in AKI by promoting HB-EGF-mediated tubular repair and regeneration, whereas it aggravates podocyte dysfunction and proteinuria by disrupting glomerular filtration integrity via degrading ZO-1. MMP-10 is also involved in cancerous invasion and emerges as a promising therapeutic target in patients with RCC. As a secreted protein, MMP-10 could be detected in the circulation and presents an inverse correlation with renal function. Due to the structural similarities between MMP-10 and the other MMPs, development of specific inhibitors targeting MMP-10 is challenging. In this review, we summarize our current understanding of the role of MMP-10 in kidney diseases and discuss the potential mechanisms of its actions.

Matrix Metalloproteinases in Helicobacter pylori-Associated Gastritis and Gastric Cancer

Gastric cancer is one of the leading causes of the cancer-related mortality worldwide. The etiology of this disease is complex and involves genetic predisposition and environmental factors, including Helicobacter pylori. Infection of the stomach with H. pylori leads to gastritis and gastric atrophy, which can progress stepwise to gastric cancer. Matrix metalloproteinases (MMPs) actively participate in the pathology development. The further progression of gastric cancer seems to be less dependent on bacteria but of intra-tumor cell dynamics. Bioinformatics data confirmed an important role of the extracellular matrix constituents and specific MMPs in stomach carcinoma invasion and metastasis, and revised their potential as predictors of the disease outcome. In this review, we describe, in detail, the impact of MMPs in H. pylori-associated gastritis and gastric cancer.

Metal-Organic-Framework-Based Hydrogen-Release Platform for Multieffective Helicobacter Pylori Targeting Therapy and Intestinal Flora Protective Capabilities

Helicobacter pylori (H. pylori) infection is the leading cause of chronic gastritis, peptic ulcer, and gastric cancer. Antibiotics, as traditional method for eliminating H. pylori, have no targeting effect, which causes serious bacterial resistance and gut dysbacteriosis. Moreover, antibiotics can hardly address hyperactive inflammatory response or damaged gastric mucosal barrier caused by H. pylori infection. Here, a pH-responsive metal-organic framework hydrogen-generation nanoparticle (Pd(H) @ ZIF-8) is reported, which is encapsulated with ascorbate palmitate (AP) hydrogel. Both in vitro and in vivo experiments demonstrate that the outer AP hydrogel can target and adhere to the inflammatory site through electrostatic interactions, and is then hydrolyzed by matrix metalloproteinase (MMP) enriching in inflammatory sites. The released Pd(H) @ ZIF-8 nanoparticles are further decomposed by gastric acid to generate zinc ions (Zn²⁺ ) and hydrogen, thus effectively killing H. pylori, alleviating inflammation and restoring impaired gastric mucosa simultaneously. Unexpectedly, this metal-organic framework hydrogen-generation platform (Pd(H) @ ZIF-8 @ AP) also has an effect toward avoiding the imbalance of intestinal flora, which thus provides a more precise, effective, and healthy strategy for the treatment of H. pylori infection.

An Overview of Helicobacter pylori Survival Tactics in the Hostile Human Stomach Environment

Helicobacter pylori is well established as a causative agent for gastritis, peptic ulcer, and gastric cancer. Armed with various inimitable virulence factors, this Gram-negative bacterium is one of few microorganisms that is capable of circumventing the harsh environment of the stomach. The unique spiral structure, flagella, and outer membrane proteins accelerate H. pylori movement within the viscous gastric mucosal layers while facilitating its attachment to the epithelial cells. Furthermore, secretion of urease from H. pylori eases the acidic pH within the stomach, thus creating a niche for bacteria survival and replication. Upon gaining a foothold in the gastric epithelial lining, bacterial protein CagA is injected into host cells through a type IV secretion system (T4SS), which together with VacA, damage the gastric epithelial cells. H. pylori does not only establishes colonization in the stomach, but also manipulates the host immune system to permit long-term persistence. Prolonged H. pylori infection causes chronic inflammation that precedes gastric cancer. The current review provides a brief outlook on H. pylori survival tactics, bacterial-host interaction and their importance in therapeutic intervention as well as vaccine development.

Helicobacter pylori-induced REDD1 modulates Th17 cell responses that contribute to gastritis

OBJECTIVE

Regulated in development and DNA damage responses-1 (REDD1) is a conserved and ubiquitous protein, which is induced in response to multiple stimuli. However, the regulation, function and clinical relevance of REDD1 in Helicobacter pylori-associated gastritis are presently unknown.

APPROACH

Immunohistochemistry, real-time PCR and Western blot analyses were performed to examine the levels of REDD1 in gastric samples from H. pylori-infected patients and mice. Gastric tissues from Redd1-/- and wildtype (WT, control) mice were examined for inflammation. Gastric epithelial cells (GECs), monocytes and T cells were isolated, stimulated and/or cultured for REDD1 regulation and functional assays.

RESULTS

REDD1 was increased in gastric mucosa of H. pylori-infected patients and mice. H. pylori induced GECs to express REDD1 via the phosphorylated cytotoxin associated gene A (cagA) that activated MAPKp38 pathway to mediate NF-κB directly binding to REDD1 promoter. Human gastric REDD1 increased with the severity of gastritis, and mouse REDD1 from non-marrow chimera-derived cells promoted gastric inflammation that was characterized by the influx of MHCII+ monocytes. Importantly, gastric inflammation, MHCII+ monocyte infiltration, IL-23 and IL-17A were attenuated in Redd1-/- mice. Mechanistically, REDD1 in GECs regulated CXCL1 production, which attracted MHCII+ monocytes migration by CXCL1-CXCR2 axis. Then H. pylori induced MHCII+ monocytes to secrete IL-23, which favored IL-17A-producing CD4+ cell (Th17 cell) polarization, thereby contributing to the development of H. pylori-associated gastritis.

CONCLUSIONS

The present study identifies a novel regulatory network involving REDD1, which collectively exert a pro-inflammatory effect within gastric microenvironment. Efforts to inhibit this REDD1-dependent pathway may prove valuable strategies in treating of H. pylori-associated gastritis.

Helicobacter pylori-Induced Heparanase Promotes H. pylori Colonization and Gastritis

Chronic gastritis caused by Helicobacter pylori (H. pylori) infection has been widely recognized as the most important risk factor for gastric cancer. Analysis of the interaction between the key participants in gastric mucosal immunity and H. pylori infection is expected to provide important insights for the treatment of chronic gastritis and the prevention of gastric cancer. Heparanase is an endoglycosidase that degrades heparan sulfate, resulting in remodeling of the extracellular matrix thereby facilitating the extravasation and migration of immune cells towards sites of inflammation. Heparanase also releases heparan sulfate-bound cytokines and chemokines that further promote directed motility and recruitment of immune cells. Heparanase is highly expressed in a variety of inflammatory conditions and diseases, but its role in chronic gastritis has not been sufficiently explored. In this study, we report that H. pylori infection promotes up-regulation of heparanase in gastritis, which in turn facilitates the colonization of H. pylori in the gastric mucosa, thereby aggravating gastritis. By sustaining continuous activation, polarization and recruitment of macrophages that supply pro-inflammatory and pro-tumorigenic cytokines (i.e., IL-1, IL-6, IL-1β, TNF-α, MIP-2, iNOS), heparanase participates in the generation of a vicious circle, driven by enhanced NFκB and p38-MAPK signaling, that supports the development and progression of gastric cancer. These results suggest that inhibition of heparanase may block this self-sustaining cycle, and thereby reduce the risk of gastritis and gastric cancer.

Helicobacter pylori-Induced Rev-erbα Fosters Gastric Bacteria Colonization by Impairing Host Innate and Adaptive Defense

BACKGROUND & AIMS

Rev-erbα represents a powerful transcriptional repressor involved in immunity. However, the regulation, function, and clinical relevance of Rev-erbα in Helicobacter pylori infection are presently unknown.

METHODS

Rev-erbα was examined in gastric samples from H pylori-infected patients and mice. Gastric epithelial cells (GECs) were isolated and infected with H pylori for Rev-erbα regulation assays. Gastric tissues from Rev-erbα^-/- and wild-type (littermate control) mice or these mice adoptively transferred with CD4⁺ T cells from IFN-γ^-/- and wild-type mice, bone marrow chimera mice and mice with in vivo pharmacological activation or inhibition of Rev-erbα were examined for bacteria colonization. GECs, CD45⁺CD11c^-Ly6G^-CD11b⁺CD68^- myeloid cells and CD4⁺ T cells were isolated, stimulated and/or cultured for Rev-erbα function assays.

RESULTS

Rev-erbα was increased in gastric mucosa of H pylori-infected patients and mice. H pylori induced GECs to express Rev-erbα via the phosphorylated cagA that activated ERK signaling pathway to mediate NF-κB directly binding to Rev-erbα promoter, which resulted in increased bacteria colonization within gastric mucosa. Mechanistically, Rev-erbα in GECs not only directly suppressed Reg3b and β-defensin-1 expression, which resulted in impaired bactericidal effects against H pylori of these antibacterial proteins in vitro and in vivo; but also directly inhibited chemokine CCL21 expression, which led to decreased gastric influx of CD45⁺CD11c^-Ly6G^-CD11b⁺CD68^- myeloid cells by CCL21-CCR7-dependent migration and, as a direct consequence, reduced bacterial clearing capacity of H pylori-specific Th1 cell response.

CONCLUSIONS

Overall, this study identifies a model involving Rev-erbα, which collectively ensures gastric bacterial persistence by suppressing host gene expression required for local innate and adaptive defense against H pylori.

Precision Medicine Approaches to Prevent Gastric Cancer

Gastric cancer remains one of the most common causes of cancer-related death worldwide, although the incidence is declining gradually. The primary risk factor for gastric cancer is Helicobacter pylori infection. The Kyoto global consensus report recommends eradication of H. pylori in all infected patients. However, because it is difficult to stratify the risk of carcinogenesis among patients with a history of H. pylori infection, annual endoscopic surveillance is performed for everyone after eradication. This review summarizes the current approaches used to screen for novel molecules that could assist in the diagnosis of gastric cancer and reduce mortality. Most well-studied molecules are tissue protein biomarkers expressed by the gastric epithelium and associated with metaplasia-dysplasia-carcinoma sequences. Other strategies focus on the origin of cancer stem cell-related markers, such as CD44, and immune reaction-related markers, such as matrix metallopeptidases. Noninvasive methods such as blood-based approaches are more attractive. Serum pepsinogen levels predict the severity of gastric mucosal atrophy before H. pylori eradication, whereas plasma ghrelin levels are associated with atrophy even after eradication. Cell-free DNAs and RNAs are attractive tools for the early detection of cancer. These ideas could lead to the development of more personalized strategies for cancer prevention based on cutting-edge technologies.

Gentiopicroside ameliorates ethanol-induced gastritis via regulating MMP-10 and pERK1/2 signaling

BACKGROUND

Excessive ethanol consumption results in gastric mucosa damage, which could further develop into chronic gastritis, peptic ulcer, and gastric cancer in humans. Gentiopicroside (GPS), a major active component of Gentianae Macrophyllae radix, was reported to play a critical role in anti-inflammation. In the study, we aimed to investigate the functional role and underlying mechanism of GPS in ethanol-induced gastritis.

METHODS

A model of gastritis was created by ethanol in C57BL/6 mice. Enzyme-linked immunosorbent assay was used to determine the concentration of TNF-α, IL-1β, IL-8, and IL-10.

RESULTS

We found that GPS treatment significantly ameliorated ethanol-induced gastritis in mice, with lower production of pro-inflammatory cytokine TNF-α, IL-1β, and IL-8 and higher levels of anti-inflammatory cytokine IL-10. The anti-inflammatory effect of GPS was further confirmed in vitro in ethanol-treated human gastric mucosal GES cells. Mechanistically, we demonstrated that GPS regulated matrix metallopeptidase expression and pERK1/2 signaling. Knockdown of matrix metallopeptidase 10 (MMP-10) greatly improved cell survival and suppressed inflammatory response in ethanol-treated GES cells. Moreover, inhibition of pERK1/2 signaling using U0126 decreased the expression of MMP-10 in ethanol-induced gastritis. U0126 treatment also suppressed the expression of TNF-α, IL-1β, and IL-8, and enhanced IL-10 expression in mice gastric mucosa.

CONCLUSIONS

Taken together, our findings suggest that GPS ameliorates ethanol-induced gastritis via regulating MMP-10 and pERK1/2 signaling, which might provide a promising therapeutic drug for ethanol-induced gastritis.

T Cell Cytokines Impact Epithelial Cell Responses during Helicobacter pylori Infection

The goal of this Brief Review is to highlight literature that demonstrates how cytokines made by T lymphocytes impact the gastric epithelium, especially during Helicobacter pylori infection. These cytokines effect many of the diverse functions of the epithelium and the epithelium's interactions with H. pylori The focal point of this Brief Review will be on how T cell cytokines impact antimicrobial function and barrier function and how T cell cytokines influence the development and progression of cancer. Furthermore, the modulation of epithelial-derived chemokines by H. pylori infection will be discussed.

The role of gut microbiota in cancer treatment: friend or foe?

The gut microbiota has been implicated in cancer and shown to modulate anticancer drug efficacy. Altered gut microbiota is associated with resistance to chemo drugs or immune checkpoint inhibitors (ICIs), whereas supplementation of distinct bacterial species restores responses to the anticancer drugs. Accumulating evidence has revealed the potential of modulating the gut microbiota to enhance the efficacy of anticancer drugs. Regardless of the valuable findings by preclinical models and clinical data of patients with cancer, a more thorough understanding of the interactions of the microbiota with cancer therapy helps researchers identify novel strategy for cancer prevention, stratify patients for more effective treatment and reduce treatment complication. In this review, we discuss the scientific evidence on the role of gut microbiota in cancer treatment, and highlight the latest knowledge and technologies leveraged to target specific bacteria that contribute to tumourigenesis. First, we provide an overview of the role of the gut microbiota in cancer, establishing the links between bacteria, inflammation and cancer treatment. Second, we highlight the mechanisms used by distinct bacterial species to modulate cancer growth, immune responses, as well as the efficacy of chemotherapeutic drugs and ICIs. Third, we demonstrate various approaches to modulate the gut microbiota and their potential in translational research. Finally, we discuss the limitations of current microbiome research in the context of cancer treatment, ongoing efforts to overcome these challenges and future perspectives.

Review - Helicobacter, inflammation, immunology and vaccines

Understanding the mechanisms involved in induction and regulation of the immune and inflammatory response to Helicobacter pylori is extremely important in determining disease outcomes. H pylori expresses a plethora of factors that influence the host response. Vaccines against H pylori are desperately needed for the prevention of gastric carcinogenesis, especially with the increasing trends in antimicrobial resistance. This review summarizes some important findings, published between 1 April 2019 and 31 March 2020, in the areas of H pylori-mediated inflammation, immunity and vaccines.

Arrestin domain containing 3 promotes Helicobacter pylori-associated gastritis by regulating protease-activated receptor 1

Arrestin domain containing 3 (ARRDC3) represents a newly discovered α-arrestin involved in obesity, inflammation, and cancer. Here, we demonstrate a proinflammation role of ARRDC3 in Helicobacter pylori–associated gastritis. Increased ARRDC3 was detected in gastric mucosa of patients and mice infected with H. pylori. ARRDC3 in gastric epithelial cells (GECs) was induced by H. pylori, regulated by ERK and PI3K-AKT pathways in a cagA-dependent manner. Human gastric ARRDC3 correlated with the severity of gastritis, and mouse ARRDC3 from non-BM–derived cells promoted gastric inflammation. This inflammation was characterized by the CXCR2-dependent influx of CD45⁺CD11b⁺Ly6C^–Ly6G⁺ neutrophils, whose migration was induced via the ARRDC3-dependent production of CXCL2 by GECs. Importantly, gastric inflammation was attenuated in Arrdc3^–/– mice but increased in protease-activated receptor 1^–/– (Par1^–/–) mice. Mechanistically, ARRDC3 in GECs directly interacted with PAR1 and negatively regulated PAR1 via ARRDC3-mediated lysosomal degradation, which abrogated the suppression of CXCL2 production and following neutrophil chemotaxis by PAR1, thereby contributing to the development of H. pylori–associated gastritis. This study identifies a regulatory network involving H. pylori, GECs, ARRDC3, PAR1, and neutrophils, which collectively exert a proinflammatory effect within the gastric microenvironment. Efforts to inhibit this ARRDC3-dependent pathway may provide valuable strategies in treating of H. pylori–associated gastritis.

A regulatory network including H. pylori, GECs, ARRDC3, PAR1, and neutrophils collectively exerts a pro-inflammatory effect within the gastric microenvironment.

Helicobacter pylori promote inflammation and host defense through the cagA-dependent activation of mTORC1

Mechanistic target of rapamycin complex 1 (mTORC1) functions as regulating different cellular processes, including cell growth, proliferation, motility, survival, metabolism, autophagy, and protein transcription. Recently, it also found to be associated with many infections and inflammatory diseases, playing complex roles in pathogens growth and inflammation regulation. However, the regulation mechanism of mTORC1 in gastric epithelial cells and its role in Helicobacter pylori (H. pylori) infection and related gastritis remain unclear. Here, we identified that the phosphorylation of mechanistic target of rapamycin (mTOR) and the expression of DEP domain-containing mTOR-interacting protein (DEPTOR) was increased in gastric mucosa of H. pylori-infected patients and mice, as well as in H. pylori-infected gastric epithelial cells, which were largely depended on H. pylori cagA. The expression of DEPTOR was regulated via mTORC1, but, in turn, inhibited mTORC1. Knockdown mTOR significantly decreased expression and secretion of cytokines tumor necrosis factor-α, interleukin-1β, and interleukin-6, chemokines CCL7 and CXCL16, and antimicrobial peptide LL37 in vitro, while knockdown DEPTOR had the opposite effect. Similar observations were made using mTOR knockout (KO) mice in vivo, moreover. The gastric inflammation was attenuated, while the bacterial burden was increased in mTOR KO mice during H. pylori infection. These findings supported H. pylori promote gastritis and inhibit bacterial colonization through the cagA-dependent activation of mTORC1.

Metabolome responses of Enterococcus faecium to acid shock and nitrite stress

Enterococcus faecium is gaining increasing interest due to its virulence and tolerance to a range of stresses (e.g., acid shock and nitrite stress in human stomach). The chemical taxonomy and basic structural features of cellular metabolite can provide us a deeper understanding of bacterial tolerance at molecular level. Here, we used hierarchical classification and molecular composition analysis to investigate the metabolome responses of E. faecium to acid shock and nitrite stress. Our results showed that considerable high biodegradable compounds (e.g., dipeptides) were produced by E. faecium under acid shock, while nitrite stress induced the accumulations of some low biodegradable compounds (e.g., organoheterocyclic compounds and benzenoids). Complete genome analysis and metabolic pathway profiling suggested that E. faecium produced high biodegradable metabolites responsible for the proton-translocation and biofilm formation, which increase its tolerance to acid shock. Yet, the presence of low biodegradable metabolites due to the nitrite exposure could disturb the bacterial productions of surface proteins, and thus inhibiting biofilm formation. Our approach uncovered the hidden interactions between intracellular metabolites and exogenous stress, and will improve the understanding of host-microbe interactions.

Expression of ETS1 in gastric epithelial cells positively regulate inflammatory response in Helicobacter pylori-associated gastritis

Gastric epithelial cells (GECs) provide the first point of contact of the host by Helicobacter pylori (H. pylori), and the interaction between H. pylori and GECs plays a critical role in H. pylori-associated diseases. Aberrant expression of transcription factors (TFs) contributes to the pathogenesis of inflammatory disorders, including H. pylori-associated gastritis. ETS (E26 transformation specific) transcription factor family is one of the largest families of evolutionarily conserved TFs, regulating critical functions during cell homeostasis. We screened ETS family gene expression in H. pylori-infected mouse and human GECs and found that ETS1 (ETS proto-oncogene 1, transcription factor) expression was highly affected by H. pylori infection. Then, we reported that ETS1 was induced in GECs by H. pylori via cagA activated NF-κB pathway. Notably, we demonstrated that proinflammatory cytokines IL-1β and TNFα have synergistic effects on ETS1 expression during H. pylori infection in an NF-κB-pathway-dependent manner. RNA-seq assay and Gene-ontology functional analysis revealed that ETS1 positively regulate inflammatory response during H. pylori infection. Increased ETS1 is also detected in the gastric mucosa of mice and patients with H. pylori infection. Collectively, these data showed that ETS1 may play an important role in the pathogenesis of H. pylori-associated gastritis.

Palmatine ameliorates Helicobacter pylori-induced chronic atrophic gastritis by inhibiting MMP-10 through ADAM17/EGFR

Palmatine (Pal), a plant-based isoquinoline alkaloid, was initially isolated from Coptidis Rhizoma (CR, Huanglian in Chinese) and considered to be a potential non-antibiotic therapeutic agent that can safely and effectively improve Helicobacter pylori (H. pylori) induced chronic atrophic gastritis (CAG). However, underlying mechanisms are unclear. In this study, we explored the protective effect of Pal on H. pylori induced CAG in vivo and in vitro. As a result, Pal alleviated the histological damage of gastric mucosa and the morphological changes of gastric epithelial cell (GES-1) caused by H. pylori. Furthermore, Pal significantly inhibited the expression of EGFR-activated ligand genes, including a disintegrin and metalloproteinase 17 (ADAM17) and heparin-binding epidermal growth factor-like growth factor (HB-EGF), and the proinflammatory factors, such as chemokine 16 (CXCL-16) and interleukin 8 (IL-8), were suppressed. In addition, Pal attenuated inflammatory infiltration of CD8⁺ T cells while promoted Reg3a expression to enhance host defense. Taken together, we concluded that Pal attenuated the MMP-10 dependent inflammatory response in the gastric mucosa by blocking ADAM17/EGFR signaling, which contributed to its gastrointestinal protective effect.

Immune Response in H. pylori-Associated Gastritis and Gastric Cancer

Helicobacter pylori (H. pylori) is the dominant member of the gastric microbiota and has infected more than half of the human population, of whom 5–15% develop gastric diseases ranging from gastritis and metaplasia to gastric cancer. These diseases always follow inflammation induced by cell surface and intracellular receptors and subsequent signaling, such as the NF-κB pathway and inflammasomes. Some types of immune cells are recruited to enforce an antibacterial response, which could be impeded by H. pylori virulence factors with or without a specific immune cell. Following decreased inflammation, neoplasm may appear with a little immune surveillance and may inhibit antitumor immunity. Therefore, the balance between H. pylori-associated inflammation and anti-inflammation is crucial for human health and remains to be determined. Here, we discuss multiple inflammation and immunoregulatory cells in gastritis and summarize the main immune evasion strategies employed by gastric cancer.

Th17 Cells in Helicobacter pylori Infection: a Dichotomy of Help and Harm

Helicobacter pylori is a Gram-negative bacterium that infects the gastric epithelia of its human host. Everyone who is colonized with these pathogenic bacteria can develop gastric inflammation, termed gastritis. Additionally, a small proportion of colonized people develop more adverse outcomes, including gastric ulcer disease, gastric adenocarcinoma, or gastric mucosa-associated lymphoid tissue lymphoma. The development of these adverse outcomes is dependent on the establishment of a chronic inflammatory response. The development and control of this chronic inflammatory response are significantly impacted by CD4⁺ T helper cell activity. Noteworthy, T helper 17 (Th17) cells, a proinflammatory subset of CD4⁺ T cells, produce several proinflammatory cytokines that activate innate immune cell antimicrobial activity, drive a pathogenic immune response, regulate B cell responses, and participate in wound healing. Therefore, this review was written to take an intricate look at the involvement of Th17 cells and their affiliated cytokines (interleukin-17A [IL-17A], IL-17F, IL-21, IL-22, and IL-26) in regulating the immune response to H. pylori colonization and carcinogenesis.

Demystifying the manipulation of host immunity, metabolism, and extraintestinal tumors by the gut microbiome

The trillions of microorganisms in the gut microbiome have attracted much attention recently owing to their sophisticated and widespread impacts on numerous aspects of host pathophysiology. Remarkable progress in large-scale sequencing and mass spectrometry has increased our understanding of the influence of the microbiome and/or its metabolites on the onset and progression of extraintestinal cancers and the efficacy of cancer immunotherapy. Given the plasticity in microbial composition and function, microbial-based therapeutic interventions, including dietary modulation, prebiotics, and probiotics, as well as fecal microbial transplantation, potentially permit the development of novel strategies for cancer therapy to improve clinical outcomes. Herein, we summarize the latest evidence on the involvement of the gut microbiome in host immunity and metabolism, the effects of the microbiome on extraintestinal cancers and the immune response, and strategies to modulate the gut microbiome, and we discuss ongoing studies and future areas of research that deserve focused research efforts.

Gastric microflora and gastric disease

Gastric environment has long been considered sterile, but the discovery of Helicobacter pylori (H. pylori) changed such concept in 1982. Over the past few decades, modern techniques have provided insight into microbial communities in the stomach and the interactions between communities, ranging from methods that rely on bacterial culture to the application of macrogenomics and high-throughput sequencing techniques. H. pylori is an important risk factor for gastric disease, but there may be other bacteria involved in the occurrence of gastric disease. This review summarizes the current progress in the understanding of the relationship between gastric microflora and gastric disease.

The important role played by chemokines influence the clinical outcome of Helicobacter pylori infection

The extended infection with Helicobacter pylori (H. pylori), one of the most frequent infectious agents in humans, may cause gastritis, peptic ulcers, gastric mucosa-associated lymphoid tissue (MALT) lymphoma, and gastric cancer. During H. pylori infection, different kinds of inflammatory cells such as dendritic cells, macrophages, neutrophils, mast cells, eosinophils, T cells and B cells are accumulated into the stomach. The interactions between chemokines and their respective receptors recruit particular types of the leukocytes that ultimately determine the nature of immune response and therefore, have a main influence on the consequence of infection. The suitable production of chemokines especially in the early stages of H. pylori infection shapes appropriate immune responses that contribute to the H. pylori elimination. The unbalanced expression of the chemokines can contribute in the induction of inappropriate responses that result in the tissue damage or malignancy. Thus, chemokines and their receptors may be promising potential targets for designing the therapeutic strategies against various types H. pylori-related gastrointestinal disorders. In this review, a comprehensive explanation regarding the roles played by chemokines in H. pylori-mediated peptic ulcer, gastritis and gastric malignancies was provided while presenting the potential utilization of these chemoattractants as therapeutic elements.