Introduction

Backgrounds: Genetic polymorphisms in inflammation related-cytokines are known to be associated with an increased risk of gastric cancer. However, the relationship between their polymorphisms and the severity of gastric inflammation remains unclear. We investigated the effects of cytokine genetic polymorphisms on the severity of gastric inflammation in Helicobacter pylori (H. pylori)-infected subjects according to sex.

Aims & Methods

This study incorporated 892 subjects with current H. pylori infection (445 males and 447 females) including 525 healthy controls, 182 patients with gastric ulcer, 185 patients with duodenal ulcer. Genotyping of IL-1B-511, IL-8-251, IL-8-781, IL-10-1082, IL-10-592, IL-6-572, TNF-A-308, TGF-B-509, IL1RN variable number of tandem repeat, ALDH2, GSTP1 and p53 codon 72 were determined by polymerase chain reaction-restriction fragment length polymorphism. Degrees of monocyte infiltration, neutrophil infiltration, atrophic gastritis (AG) and intestinal metaplasia (IM) in the antrum and corpus were evaluated accordingly to the updated Sydney System. The severity of gastric inflammation was divided into two groups, no/mild and moderate/severe, and were compared between genotypes adjusted age, disease status and H. pylori virulent factors.

Results

In males, moderate/severe AG of the corpus was significantly higher in IL-1B-511 C/C than IL1B-511 T carriers (17.9 vs 7.7%; adjusted hazard ratio (HR) = 3.140, 95% confidence interval (CI) = 1.320-7.471; p = 0.018), while no associations between IL-1B-511 polymorphism and gastric inflammation were found in females. IL-8-251 A/A was significantly associated with moderate/severe AG of the corpus than IL-8-251 T carriers only in females (21.2 vs 6.6%; adjusted HR = 3.520, 95% CI = 1.539-8.051; p = 0.003). IL-8-781 T/T showed significantly more frequent in females with moderate/severe AG of antrum than IL-8-781 C carriers (12.9 vs 4.6%; adjusted HR = 2.835, 95% CI = 1.166-6.892; p = 0.022), and conversely, IL-8-781 C carriers were significantly associated with moderate/severe AG of the antrum than IL-8-781 T/T in males (23.3 vs 8.3%; adjusted HR = 3.573, 95% CI = 1.033-12.362; p = 0.044). No significant associations were observed in the frequencies of the genotypes of other genetic polymorphisms with severity of gastric inflammation.

Table. Summary of the results of this study

Conclusion

These results suggest that cytokine genetic polymorphisms such IL-1B-511 C/T, IL-8-251 T/A and IL-8-781 C/T are one of several factors that determine severity of AG with sex difference.

Introduction

In Colombia, the severity of lesions in gastric cancer pathogenesis varies depending on geographical location (Pacific coast: Low risk; Andean region: High risk), human ancestry, and Helicobacter pylori strain. Helicobacter pylori, the main causative agent of gastric adenocarcinoma, triggers a proinflammatory Th1 immune response and dysbiosis of the gastric microbiota upon infection by this microorganism.

Aims & Methods

Our research focuses on understanding how the ancestral origins of both Helicobacter pylori and humans in Colombia influence the composition and behavior of the gastric microbiota, particularly in relation to the immune response and genetic polymorphisms associated with gastric cancer pathogenesis. Through comprehensive genomic, microbiome, and immunological analyses in individuals with high and low risk of gastric cancer in Colombia.

Results

It was observed that in Colombian Pacific coast reveal a predominant presence of Helicobacter pylori strains hspWAfrica and hpAfrica1, aligning closely with the African ancestry of the human population. However, a new strain, hspColombia, is notably present among human individuals of European and Native American descent in the Andean region. Immune responses differ between these regions, with an anti-inflammatory Th2 response prevalent on the Pacific coast, contrasting with a Th1 response observed in the Andean region, linked to specific human polymorphisms such as Mutations IL-1B-511TT (72%) and IL-10-1082AG (79%). These mutations elevate the risk of developing precursor lesions of gastric cancer by 5.45 times (OR: 5.45; CI: 95%). Comparative analysis of the microbiota indicates a decline in species diversity with increasing severity of gastric lesions due to Helicobacter pylori infection. Among the most representative genera of the gastric microbiota were Helicobacter, Pseudomonas, Methylobacterium, Streptococcus, Corynebacterium, and Staphylococcus, as determined by U test (p < 0.001).

Conclusion

The interplay between geographical and genomic variations of Helicobacter pylori and humans in Colombia is pivotal in driving the progression of lesions in gastric pathogenesis. The immune response, marked by Th1 and Th2 profiles, exhibits regional disparities and is closely tied to human polymorphisms, notably mutations in the IL-1B-511TT and IL-10-1082AG genes, which heighten the risk of gastric cancer. Helicobacter pylori infection modulates the diversity of the gastric microbiota, culminating in a reduction in species diversity as gastric lesion severity escalates. This underscores the significance of maintaining the coevolutionary equilibrium between Helicobacter pylori and humans, as its disruption critically impacts dysbiosis in the gastric microbiota, exacerbates proinflammatory immune responses, and contributes to the progression of lesions in the pathogenesis of gastric cancer in Colombia.

References

Malfertheiner, P., Camargo, M. C., El-Omar, E., Liou, J. M., Peek, R., Schulz, C., & Suerbaum, S. (2023). Helicobacter pylori infection. Nature reviews Disease primers, 9(1), 19.

Introduction

Helicobacter pylori (H.pylori) infection is the main risk factor for gastric cancer. Infection leads to chronic inflammation and gastric gland hyperplasia. We found that infection induces alterations in the stromal niche, such as inhibited secretion of BMP ligands and increased expression of BMP inhibitors. BMP signaling is known to be involved in differentiation of base progenitor cells into pit secretory cells. However, whether it plays a role in regulating mucosal antimicrobial defense is still unknown and we now investigate how the downregulation of BMP signaling affects mucosal inflammatory responses.

Aims & Methods

Exploiting in vivo murine models as well as in vitro assays, we aim to investigate how the downregulation of epithelial BMP signaling affects mucosal homeostasis.
3D gastric organoids were used to explore the role of BMP in epithelial responses to microbial proteins (qPCR, Western Blotting). The effects of epithelial BMP downregulation and stromal Il1r1 signaling were investigated by exploiting conditional knockout mice (Axin2CreERT2-Bmpr1afl/fl or Bmpr1a KO; Col1a2CreERT2-Il1r1fl/fl or Il1r1 KO) either uninfected or infected with H.pylori PMSS1. Tissue samples were analyzed via immunofluorescence, RNA-in situ hybridization and gene expression analysis (qPCR, whole transcriptome). 2D primary murine stromal cell culture were exploited to investigate stromal responses to inflammatory triggers.

Results

Exploiting 3D organoids, we demonstrate that epithelial cells activate NF-κB signaling in response to microbe-derived proteins, while this effect is inhibited upon BMP signaling activation. In vivo, inhibition of BMP signaling in the epithelium via knockout of Bmpr1a (Bmpr1a KO) not only causes gland hyperplasia but also strongly enhances inflammation at the pit of gastric glands, where it is absent in mice with functional BMP signaling. We explore the consequences of increased inflammation upon epithelial Bmpr1a KO, demonstrating via whole transcriptome analysis that this is linked to enhanced antimicrobial tissue responses and that KO mice show reduced H.pylori colonization. Moreover, we discover that the influx of IL-1β producing cells observed upon BMP signaling downregulation has an impact on stromal cells, which in turn produce pro-regenerative factors causing epithelial reprogramming into a highly proliferative fetal-like regenerative state. We demonstrate that Il1r1 KO mice, where stromal cells lack the ability to respond to IL-1β, do not show fetal-like reprogramming and are more colonized by H.pylori.

Conclusion

Chronic H.pylori infection causes tissue reprogramming into a fetal-like state via a crosstalk between epithelial, stromal and immune cells. This state is linked to an enhanced proinflammatory response, increased proliferation and boosters antimicrobial defense. We propose that long-term activation of this state may enhance the risk for malignant transformation.

Introduction

Helicobacter pylori (H. pylori) infection is recognized as a major cause of gastric carcinogenesis. However, basic research has demonstrated that H. pylori infection alone is insufficient to induce gastric cancer, suggesting that specific intragastric environmental factors may promote carcinogenesis. Both Japan and Lithuania are known to have a high incidence of gastric cancer. Therefore, comprehensive analysis of intragastric microenvironmental factors in patients with gastric cancer and those with atrophic gastritis in both countries is considered essential for advancing gastric cancer prevention.

Aims & Methods

This study compares intragastric factors—such as endoscopic findings, metabolites, and histopathological markers—among gastric cancer patients, H. pylori-infected patients, and non-infected individuals in Japan and Lithuania (UMIN000050183). To analyze background factors in gastric cancer, we used B3 Analytics, an explainable artificial intelligence (AI) platform developed by Hitachi Ltd. that identifies key determinants such as biomarkers.

Results

A total of 90 patients from Japan and 88 from Lithuania were enrolled in the study.
International comparison of progression patterns of gastric mucosal atrophy and intestinal metaplasia: Progression of gastric mucosal atrophy and intestinal metaplasia with aging was observed in the Japanese cohort, whereas in the Lithuanian cohort, some cases showed no clear age-related progression (OLGIM: Japan, R² = 0.626, P < 0.001; Lithuania, R² = 0.028, P = 0.622; OLGA: Japan, R² = 0.277, P = 0.004; Lithuania, R² = 0.028, P = 0.622). Furthermore, a strong correlation was identified between OLGIM and endoscopic atrophy grading according to the Kimura-Takemoto classification (r = 0.728, P < 0.001). These findings suggest that even with similar H. pylori infection status, regional differences may influence the progression of gastric mucosal damage and associated cancer risk.
Comparison of short-chain fatty acid concentrations in gastric juice: Measurements of the concentrations of seven types of short-chain fatty acids (SCFAs) were conducted. In both countries, propionic acid was detected at relatively high concentrations. In contrast, for butyric acid and isobutyric acid, a large number of samples from the Lithuanian cohort were below the detection limit. No statistically significant differences in SCFA concentrations were observed.
Cluster analysis of a carcinogenesis prediction model using an explainable AI platform: Using B3 Analytics, an explainable AI platform, we constructed a carcinogenesis prediction model and classified subjects into three clusters (Cluster 0, 1, and 2), allowing more accurate prediction of gastric cancer risk. Among these, Cluster 2 exhibited the highest risk of gastric cancer (44.4%), compared to the lower-risk Clusters 0 and 1 (17.2% and 16.0%, respectively). As expected, older age, male sex, and extensive endoscopic mucosal atrophy were significantly more prevalent in Cluster 2, consistent with their known association with gastric cancer risk. Notably, expression levels of CD44 and CAPZA1 were significantly lower in Cluster 2, suggesting a novel inverse association with gastric carcinogenesis risk.

Conclusion

This study revealed regional differences between Japan and Lithuania regarding gastric mucosal lesions and intragastric metabolic status after H. pylori infection. Moreover, the application of a machine learning model enabled the identification of novel predictive factors for gastric carcinogenesis.

Disclosure

HS receives lecture fees from Astellas, Otsuka and Takeda Pharm. Co. Ltd. and joint research funding from Tohso Co.
This work was supported by the Japan Society for the Promotion of Science (JSPS) in collaboration with RCL, Lithuania (No. 120254201) and the AMED under Grant Numbers 24jm0210088h0004, to HS.

Introduction

Helicobacter pylori is the main risk factor for gastric cancer, but only 1 to 5% of infected individuals develop gastric cancer, suggesting that additional factors are required. The Rspo3/Wnt signaling pathway is essential for the proliferation and self-renewal of stem cells and controls gastric epithelial differentiation. 50% of gastric cancer samples show aberration of Rspo3/Wnt signaling.

Aims & Methods

We hypothesize that the pro-carcinogenic potential of infection with Helicobacter pylori is context-dependent and that synergistic effects of Rspo3/Wnt signaling and infection-specific tissue responses drive carcinogenesis. We aim to mechanistically dissect this interplay.
Using conditional mouse models enabling the up- and downregulation of Rspo3 in stromal myofibroblasts and infecting them with Helicobacter pylori, we analyze the role of stromal signaling in Helicobacter pylori-driven carcinogenesis. In addition, we apply a new conditional mouse model enabling the stomach-specific epithelial knockout of the Wnt antagonist Apc to understand the contribution of epithelial Wnt mutation to epithelial behavior and identity and stromal signaling in non-infected and Helicobacter pylori-infected mice. Methodologically, we apply immunofluorescence staining followed by quantitative and spatial analyses and single-cell RNA sequencing, microarray analyses, and gene set enrichment analyses to discover gene expression patterns, dissect cellular heterogeneity, and identify central driver pathways. Using 3D organoid models, we investigate the mechanisms promoting epithelial proliferation and malignant transformation in the context of infection with Helicobacter pylori. We verify the murine results by immunohistological analyses of human gastric cancer tissue.

Results

We find that infection with Helicobacter pylori induces epithelial reprogramming into a regenerative fetal-like state characterized by hyperproliferation and the activation of YAP signaling. Reprogramming depends on stromal Rspo3 signaling. In mice that overexpress Rspo3, chronic Helicobacter pylori-driven inflammation locks the epithelium in the regenerative state, promoting metaplastic changes. Knockout of Rspo3 blocks this response. Rspo3 also promotes the infiltration of immune cells into the tissue, which further perpetuates pathology. Interestingly, infected Rspo3 overexpressing mice show a significantly higher number of PD-L1 positive cells than infected wild-type mice. We confirm the positive correlation between Rspo3 and PD-L1 expression in tissue microarrays of 240 gastric cancers.
Consistent with previous murine and clinical data, knockout of Apc in epithelial cells does not lead to gastric cancer in the absence of infection with Helicobacter pylori. In contrast, infected Apc knockout mice develop carcinogenic lesions after 2 months. Immunofluorescence labeling, single-cell RNA sequencing, and microarray analyses reveal an infection-dependent remodeling of the epithelial niche in Apc knockout mice.

Conclusion

Together, we discover that cell-intrinsic Wnt signaling synergizes with cell-extrinsic infection-driven alterations of the niche to drive tissue reprogramming and carcinogenic transformation. This work demonstrates the crucial interaction of genetic and environmental factors in gastric carcinogenesis.