# Determination of the Roles of H. pylori Outer Membrane Virulence Factors and Pyroptosis-Associated NLRP3, ASC, Caspase-1, Gasdermin D, IL-1β, and IL-18 in Ulcer and Gastritis Pathogenesis

## TL;DR

This study shows how H. pylori infection affects inflammatory cell death in the stomach, linking specific bacterial genes to disease severity.

## Contribution

The study identifies specific H. pylori genes that influence pyroptosis markers in gastritis and ulcers.

## Key findings

- H. pylori infection increases pyroptosis markers like NLRP3 and IL-1β in gastric tissues.
- The vacA m2 allele is linked to higher GSDMD expression in ulcers, while alpA is associated with reduced Gasdermin D activation.
- Bacterial genes like vacA and babB correlate with stronger inflammatory responses in infected patients.

## Abstract

Helicobacter pylori is a prevalent gastric bacterium associated with gastritis and ulcers. This study explored how the bacterium may trigger pyroptosis—a form of inflammatory cell death—in stomach tissue. We analyzed tissue samples from patients with and without H. pylori infection to measure the activity of genes and proteins involved in this process. Our results showed that infection increased key pyroptosis markers, especially in ulcer cases. Certain bacterial genes, such as vacA and babB, were linked to stronger inflammatory responses, while another gene, alpA, was associated with reduced activation of a key pyroptosis protein. These findings suggest that H. pylori may influence disease severity by altering the host’s immune response.

Background: This study aims to investigate the association between pyroptosis and the outer membrane virulence factor of H. pylori in patients with gastritis and ulcers. Methods: DNA, RNA, and protein were extracted from a single tissue sample taken from the antrum region of the stomach of volunteer patients. The expression of bacterial outer membrane virulence genes was analyzed at the gene level, and the expression levels of key pyroptosis markers were compared between H. pylori-infected and uninfected gastritis and ulcer patient groups. Results: H. pylori infection induced significant alterations in the expression levels of pyroptosis markers, including ASC, NLRP3, caspase-1, GSDMD, IL-18, and IL-1β, indicating a strong association with gastritis and ulcer pathology. Statistically significant correlations were observed between elevated levels of these markers and the activation of caspase-1 across different patient cohorts, supporting effective detection of pyroptosis. Both pro and active forms of caspase-1, GSDMD, IL-18, and IL-1β were assessed, revealing pyroptotic activity in specific patient samples. The vacA m2 allele showed a distinct ASC response in gastritis versus ulcer patients and was associated with increased GSDMD expression in ulcerative cases. Along with the babB gene, this allele appears to play a critical role in the interaction between H. pylori virulence and host pyroptotic responses. A statistically significant negative association was identified between the presence of the H. pylori alpA gene and Gasdermin D expression (odds ratio = 0, p < 0.01), suggesting that Gasdermin D was absent in all alpA-positive samples. Conclusion: This study provides novel insights into the interrelation between the virulence factors of H. pylori and pyroptosis in gastritis and ulcer diseases. Our findings demonstrate that H. pylori infection significantly alters the expression levels of pyroptosis markers, including ASC, NLRP3, caspase-1, GSDMD, IL-18, and IL-1β, in gastric tissues. Notably, the vacA m2 allele was associated with a differential response in ASC expression among patients with gastritis and ulcers, correlating with increased GSDMD levels in ulcerative conditions. The presence of the H. pylori alpA gene is markedly associated with the lack of Gasdermin D activation, indicating a possible suppressive function or immune evasion tactic. These results underscore the critical role of H. pylori virulence determinants in modulating pyroptosis and suggest that understanding this relationship may pave the way for developing targeted therapeutic strategies to mitigate H. pylori-associated pathologies.