High expression of Helicobacter pylori VapD in both the intracellular environment and biopsies from gastric patients with severity

Abstract

Helicobacter pylori is a Gram-negative bacterium that causes chronic atrophic gastritis and peptic ulcers and it has been associated with the development of gastric adenocarcinoma and mucosa-associated lymphoid tissue (MALT). One of the more remarkable characteristics of H. pylori is its ability to survive in the hostile environment of the stomach. H. pylori regulates the expression of specific sets of genes allowing it to survive high acidity levels and nutrient scarcity. In the present study, we determined the expression of virulence associated protein D (VapD) of H. pylori inside adenocarcinoma gastric (AGS) cells and in gastric biopsies. Using qRT-PCR, VapD expression was quantified in intracellular H. pylori-AGS cell cultures at different time points and in gastric mucosa biopsies from patients suffering from chronic atrophic gastritis, follicular gastritis, peptic ulcers, gastritis precancerous intestinal metaplasia and adenocarcinoma. Our results show that vapD of H. pylori presented high transcription levels inside AGS cells, which increased up to two-fold above basal values across all assays over time. Inside AGS cells, H. pylori acquired a coccoid form that is metabolically active in expressing VapD as a protection mechanism, thereby maintaining its permanence in a viable non-cultivable state. VapD of H. pylori was expressed in all gastric biopsies, however, higher expression levels (p = 0.029) were observed in gastric antrum biopsies from patients with follicular gastritis. The highest VapD expression levels were found in both antrum and corpus gastric biopsies from older patients (>57 years old). We observed that VapD in H. pylori is a protein that is only produced in response to interactions with eukaryotic cells. Our results suggest that VapD contributes to the persistence of H. pylori inside the gastric epithelial cells, protecting the microorganism from the intracellular environment, reducing its growth rate, enabling long-term infection and treatment resistance. PLOS ONEPLOS ONE | https://doi.org/10.1371/journal.pone.et al. (2020) High expression of Helicobacter pylori VapD in both the intracellular environment and biopsies from gastric patients with severity. PLoS ONE 15(3): e0230220. https://doi.org/10.

Comparative genomics analysis of statistically significant genomic islands of Helicobacter pylori strains for better understanding the disease prognosis

“…Another report showed treatment of biopsy samples with chloramphenicol and kanamycin induced the expression of TAs. These suggested that vapD is a virulent factor, protects the bacterium by aiding biofilm formation [ 66 , 67 ]. It helps the bacterium to survive in a hostile environment.…”

Helicobacter pylori in gastric cancer: Features of infection and their correlations with long-term results of treatment

“…It should be noted that the higher infection by coccoid forms of H. pylori in patients with GC, compared to patients with gastritis or gastric ulcer, had been mentioned by other researchers[ 57 ]. A number of studies have shown that coccoid forms of H. pylori retained urease activity[ 58 ] and the expression of such antigens as CagA, UreA, porin, components of the Cag type IV secretion system (TFSS), antigen-binding adhesin of the blood group BabA and others[ 59 , 60 ].…”

Defining the Helicobacter pylori Disease-Specific Antigenic Repertoire

“…A relevant increase was also found for the virulence-associated protein VapD (HP0967) by sera of patients with AIG (selection B). In a recent paper by Morales-Espinosa et al (2020) high level of expression of virulence-associated protein D (VapD) of H. pylori were outlined inside adenocarcinoma gastric (AGS) cells and in gastric biopsies from patients suffering from different HP-related diseases. They observed that VapD is only expressed in the bacterium as a consequence of its interaction with the host cells, suggesting that it might contribute to H. pylori persistence inside the gastric epithelial cells, being involved in the protection of the bacterium from the intracellular environment and in its growth rate reduction, as well as enabling long-term infection and treatment resistance.…”

“…They observed that VapD is only expressed in the bacterium as a consequence of its interaction with the host cells, suggesting that it might contribute to H. pylori persistence inside the gastric epithelial cells, being involved in the protection of the bacterium from the intracellular environment and in its growth rate reduction, as well as enabling long-term infection and treatment resistance. However in their work Morales-Espinosa et al (2020) Did not test the reactivity of patients sera against VapD protein, they analyzed VapD expression in AGS cells in in vitro time course experiments and they tested the expression level of VapD by RT qPCR in 82 gastric biopsies from patients outlying high expression levels of this gene/protein in vivo in particular in association with follicular gastritis. Thus, in the light of this work we think that our finding related to an antibody response against VapD in patients can be considered promising for future validations.…”