Increased LIGHT expression and activation of non-canonical NF-κB are observed in gastric lesions of MyD88-deficient mice upon Helicobacter felis infection

Molecular surveillance of Helicobacter species with high prevalence from two streams with various wastewater pollution in Taiwan

Helicobacter species are potential zoonotic pathogens classified as either enterohepatic or gastric. Helicobacter infection can be transmitted through wastewater from households and livestock and through water from irrigation and streams. In this study, the distribution and source of Helicobacter species in the Donggang and Yenshui rivers, two natural water bodies with different characteristics, were analyzed. A total of 44 water samples were collected over the four seasons. The samples were subjected to Helicobacter 16 s rRNA gene PCR, followed by sequencing and comparison for identification and analysis. The detection rate of Helicobacter species in both rivers was 79.55%, with H. kayseriensis (10/35, 28.57%) being the most common species. Analysis of the environment around the sampling sites showed a high detection rate in the livestock-rich area, and the results of BLAST for species identification and comparison indicated feces as the contamination source. The area around the Donggang River was developed for animal husbandry, led to a high detection rate of Helicobacter species. Many Helicobacter species were identified to have a risk of zoonotic transmission, especially if the stream is used as a source of drinking, agricultural, or even aquacultural water. The high presence of Helicobacter species in natural water bodies suggests that wastewater treatment is an effective strategy to control pathogen spread. Therefore, investigation and monitoring of pathogens in wastewater are highly important. However, methods for the isolation and culture of Helicobacter species in natural waters have yet to be developed. Hence, future research should focus on developing such methods.

TRIF-IFN-I pathway in Helicobacter-induced gastric cancer in an accelerated murine disease model and patient biopsies

Helicobacter pylori (H. pylori) infection is a known cause of many digestive diseases, including gastritis, peptic ulcers, and gastric cancer. However, the underlying mechanisms by which H. pylori infection triggers these disorders are still not clearly understood. Gastric cancer is a slow progressing disease, which makes it difficult to study. We have developed an accelerated disease progression mouse model, which leverages mice deficient in the myeloid differentiation primary response 88 gene (Myd88-/-) infected with Helicobacter felis (H. felis). Using this model and gastric biopsy samples from patients, we report that activation of the Toll/interleukin-1 receptor (TIR)-domain-containing adaptor inducing interferon-β (TRIF)-type I interferon (IFN-I) signaling pathway promotes Helicobacter-induced disease progression toward severe gastric pathology and gastric cancer development. Further, results implicated downstream targets of this pathway in disease pathogenesis. These findings may facilitate stratification of Helicobacter-infected patients and thus enable treatment prioritization of patients.

GRB7 plays a promoting role in the progression of gastric cancer

BACKGROUND

Gastric cancer is a clinically common tumor, showing an upward trend of both incidence and mortality. GRB7 has been identified as a vital regulator in tumor progression. This study aims to uncover the biological function of GRB7 in gastric cancer process.

METHODS

immunohistochemical (IHC) staining using a tissue microarray (TMA), quantitative reverse transcription PCR (qRT-PCR) and Western blotting were performed to detect the expression of genes. Furthermore, gastric cancer cell lines AGS and MGC-803 were transfected with short hairpin RNAs against GRB7. The biological function of GRB7 in gastric cancer cells were examined by CCK-8, flow cytometry, wound healing and Transwell assays. Then, in vivo tumor formation assay was conducted to explore the effects of GRB7 on tumor growth. Finally, expression levels of proteins related to cell functions were determined by Western blotting. Coimmunoprecipitation (CoIP) assay was performed to assess the protein-protein interaction.

RESULTS

GRB7 was up-regulated in gastric cancer tissues and cell lines, and its expression was inversely proportional to survival of gastric cancer patients. Moreover, GRB7 knockdown inhibited proliferative, migratory abilities, as well as promoted cell apoptosis in gastric cancer cells. Further study suggested that GRB7 silencing could suppress gastric cancer tumor growth in vivo. Furthermore, our study uncovered an important interaction between GRB7 and MyD88. Silencing MyD88 was observed to alleviate the malignant phenotypes promoted by GRB7 in gastric cancer cells.

CONCLUSIONS

Together, this study provided evidence that GRB7 may be an effective molecular targets for the treatment of gastric cancer.

Activation of the TRIF pathway and downstream targets results in the development of precancerous lesions during infection with Helicobacter

Helicobacter pylori ( H. pylori) infection is an established cause of many digestive diseases, including gastritis, peptic ulcers, and gastric cancer. However, the mechanism by which infection with H. pylori causes these disorders is still not clearly understood. This is due to insufficient knowledge of pathways that promote H. pylori -induced disease progression. We have established a Helicobacter -induced accelerated disease progression mouse model, which involves infecting mice deficient in the myeloid differentiation primary response 88 gene ( Myd88 -/- ) with H. felis . Using this model, we report here that that progression of H. felis -induced inflammation to high-grade dysplasia was associated with activation of type I interferon (IFN-I) signaling pathway and upregulation of related downstream target genes, IFN-stimulated genes (ISGs). These observations were further corroborated by the enrichment of ISRE motifs in the promoters of upregulated genes. Further we showed that H. felis -induced inflammation in mice deficient in Toll/interleukin-1 receptor (TIR)-domain-containing adaptor inducing interferon-β (TRIF, Trif Lps 2 ) did not progress to severe gastric pathology, indicating a role of the TRIF signaling pathway in disease pathogenesis and progression. Indeed, survival analysis in gastric biopsy samples from gastric cancer patients illustrated that high expression of Trif was significantly associated with poor survival in gastric cancer.

Genomically Silent Refractory Gastric Cancer in a Young Patient Exhibits Overexpression of CXCL5

Gastric cancer is the third leading cause of cancer-related deaths, with more than one million new cases and approximately 841,000 deaths annually worldwide. We report a case of a young patient (25 years old) with an aggressive form of gastric cancer. The patient had previously been treated for Helicobacter pylori (H. pylori), which is a main risk factor for developing gastric cancer. Genetic testing showed an E-cadherin (CDH1) germline mutation of unknown significance. After eight cycles of chemotherapy, a positron emission tomography (PET) scan showed disease progression with an enlarging hypermetabolic right adnexal mass suspicious for metastatic disease. Tumor pathology demonstrated invasive and poorly differentiated gastric carcinoma. The analysis of the tumor biopsy indicated the very high expression of a chemokine, C-X-C motif chemokine 5 (CXCL5). The combination of H. pylori infection with an existence of a rare CDH1 mutation could have contributed to this aggressive gastric cancer.

Engagement of CEACAM1 by Helicobacterpylori HopQ Is Important for the Activation of Non-Canonical NF-κB in Gastric Epithelial Cells

The gastric pathogen Helicobacter pylori infects half of the world's population and is a major risk factor for gastric cancer development. In order to attach to human gastric epithelial cells and inject the oncoprotein CagA into host cells, H. pylori utilizes the outer membrane protein HopQ that binds to the cell surface protein CEACAM, which can be expressed on the gastric mucosa. Once bound, H. pylori activates a number of signaling pathways, including canonical and non-canonical NF-κB. We investigated whether HopQ-CEACAM interaction is involved in activating the non-canonical NF-κB signaling pathway. Different gastric cancer cells were infected with the H. pylori wild type, or HopQ mutant strains, and the activation of non-canonical NF-κB was related to CEACAM expression levels. The correlation between CEACAM levels and the activation of non-canonical NF-κB was confirmed in human gastric tissue samples. Taken together, our findings show that the HopQ-CEACAM interaction is important for activation of the non-canonical NF-κB pathway in gastric epithelial cells.

LncRNA HOXA-AS3 promotes gastric cancer progression by regulating miR-29a-3p/LTβR and activating NF-κB signaling

BACKGROUND

Gastric cancer (GC) is among the most common and deadliest cancers globally. Many long non-coding RNAs (lncRNAs) are key regulators of GC pathogenesis. This study aimed to define the role of HOXA-AS3 in this oncogenic context.

METHODS

Levels of HOXA-AS3 expression in GC were quantified via qPCR. The effects of HOXA-AS3 knockdown on GC cells function were evaluated in vitro using colony formation assays, wound healing assays and transwell assays. Subcutaneous xenograft and tail vein injection tumor model systems were generated in nude mice to assess the effects of this lncRNA in vivo. The localization of HOXA-AS3 within cells was confirmed by subcellular fractionation, and predicted microRNA (miRNA) targets of this lncRNA and its ability to modulate downstream NF-κB signaling in GC cells were evaluated via luciferase-reporter assays, immunofluorescent staining, and western blotting.

RESULTS

GC cells and tissues exhibited significant HOXA-AS3 upregulation (P < 0.05), and the levels of this lncRNA were found to be correlated with tumor size, lymph node status, invasion depth, and Helicobacter pylori infection status. Knocking down HOXA-AS3 disrupted GC cell proliferation, migration, and invasion in vitro and tumor metastasis in vivo. At a mechanistic level, we found that HOXA-AS3 was able to sequester miR-29a-3p, thereby regulating the expression of LTβR and modulating NF-κB signaling in GC.

CONCLUSION

HOXA-AS3/miR-29a-3p/LTβR/NF-κB regulatory axis contributes to the progression of GC, thereby offering novel target for the prognosis and treatment of GC.

Microbiome Signatures in a Fast- and Slow-Progressing Gastric Cancer Murine Model and Their Contribution to Gastric Carcinogenesis

Gastric cancer is the third most common cause of death from cancer in the world and infection with Helicobacter pylori (H. pylori) is the main cause of gastric cancer. In addition to Helicobacter infection, the overall stomach microbiota has recently emerged as a potential factor in gastric cancer progression. Previously we had established that mice deficient in myeloid differentiation primary response gene 88 (MyD88, Myd88^-/- ) rapidly progressed to neoplasia when infected with H. felis. Thus, in order to assess the role of the microbiota in this fast-progressing gastric cancer model we investigated changes of the gastric microbiome in mice with different genotypic backgrounds: wild type (WT), MyD88-deficient (Myd88^-/- ), mice deficient in the Toll/interleukin-1 receptor (TIR) domain-containing adaptor-inducing interferon-β (TRIF, Trif ^Lps2), and MyD88- and TRIF-deficient (Myd88^-/- /Trif ^Lps2, double knockout (DKO)) mice. We compared changes in alpha diversity, beta diversity, relative abundance, and log-fold differential of relative abundance ratios in uninfected and Helicobacter infected mice and studied their correlations with disease progression to gastric cancer in situ. We observed an overall reduction in microbial diversity post-infection with H. felis across all genotypes. Campylobacterales were observed in all infected mice, with marked reduction in abundance at 3 and 6 months in Myd88^-/- mice. A sharp increase in Lactobacillales in infected Myd88^-/- and DKO mice at 3 and 6 months was observed as compared to Trif ^Lps2 and WT mice, hinting at a possible role of these bacteria in gastric cancer progression. This was further reinforced upon comparison of Lactobacillales log-fold differentials with histological data, indicating that Lactobacillales are closely associated with Helicobacter infection and gastric cancer progression. Our study suggests that differences in genotypes could influence the stomach microbiome and make it more susceptible to the development of gastric cancer upon Helicobacter infection. Additionally, increase in Lactobacillales could contribute to faster development of gastric cancer and might serve as a potential biomarker for the fast progressing form of gastric cancer.

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.

Review: Other Helicobacter species

This review covers the most important, accessible, and relevant literature published between April 2019 and April 2020 in the field of non-Helicobacter pylori Helicobacter species (NHPH). The initial part of the review covers new insights regarding the presence of gastric and enterohepatic NHPH in humans and animals, while the subsequent section focuses on the progress in our understanding of animal models, the pathogenicity and omics of these species. Over the last year, the clinical relevance of gastric NHPH infections in humans was highlighted. With regard to NHPH in animals, the ancestral source of Helicobacter suis was further established showing that Cynomolgus macaques are the common ancestor of the pig-associated H. suis population, and 3 novel Helicobacter species isolated from the gastric mucosa of red foxes were described. "Helicobacter burdigaliensis" sp nov. and "Helicobacter labetoulli" sp nov. were proposed as novel enterohepatic Helicobacter species associated with human digestive diseases. An analysis of Helicobacter cinaedi recurrent infections in humans proposed long-term antibiotic therapies. Several studies using rodent models further elucidated the mechanisms underlying the development of NHPH-related disease, as well as intestinal immunity in inflammatory bowel disease models. Omics approaches supported Helicobacteraceae taxonomy and unraveled the transcriptomic signatures of H. suis and Helicobacter heilmannii upon adherence to the human gastric epithelium. With regard to virulence, data showed that the nuclear remodeling promoted by cytolethal distending toxin of Helicobacters involves the MAFB oncoprotein and is associated with nucleoplasmic reticulum formation in surviving cells.

The role of Helicobacter pylori in cardiovascular toxicity mechanisms

Despite the long history of the concept where infection plays a significant role in cardiovascular diseases (atherosclerosis in particular), today it is relevant and represented a significant interest.

This article discusses H. pylori role in mechanisms of cardiovascular homeostasis disturbance. H. pylori involvement in atherogenic damage of arteries, and/or plaque destabilization is no doubt. This vidence is detailed in this review article.