Evaluating the origin and virulence of a Helicobacter pylori cagA-positive strain isolated from a non-human primate

Sci Rep. 2018 Oct 29;8(1):15981. doi: 10.1038/s41598-018-34425-4.

Abstract

Helicobacter pylori cagA-positive strains are critically involved in the development of gastric cancer. Upon delivery into gastric epithelial cells via type IV secretion, the cagA-encoded CagA interacts with and thereby perturbs the pro-oncogenic phosphatase SHP2 and the polarity-regulating kinase PAR1b via the tyrosine-phosphorylated EPIYA-C/D segment and the CM sequence, respectively. Importantly, sequences spanning these binding regions exhibit variations among CagA proteins, which influence the pathobiological/oncogenic potential of individual CagA. Here we isolated an H. pylori strain (Hp_TH2099) naturally infecting the stomach of a housed macaque, indicating a zoonotic feature of H. pylori infection. Whole genome sequence analysis revealed that Hp_TH2099 belongs to the hpAsia2 cluster and possesses ABC-type Western CagA, which contains hitherto unreported variations in both EPIYA-C and CM sequences. The CM variations almost totally abolished PAR1b binding. Whereas pTyr + 5 variation in the EPIYA-C segment potentiated SHP2-binding affinity, pTyr-2 variation dampened CagA tyrosine phosphorylation and thus impeded CagA-SHP2 complex formation. As opposed to the H. pylori standard strain, infection of mouse ES cell-derived gastric organoids with Hp_TH2099 failed to elicit CagA-dependent epithelial destruction. Thus, the macaque-isolated H. pylori showed low virulence due to attenuated CagA activity through multiple substitutions in the sequences involved in binding with SHP2 and PAR1b.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Antigens, Bacterial / chemistry
  • Antigens, Bacterial / genetics*
  • Antigens, Bacterial / metabolism
  • Bacterial Proteins / chemistry
  • Bacterial Proteins / genetics*
  • Bacterial Proteins / metabolism
  • Binding Sites
  • Cell Cycle Proteins / metabolism
  • Gastric Juice / microbiology
  • Genes, Bacterial
  • Helicobacter Infections / microbiology
  • Helicobacter Infections / transmission
  • Helicobacter Infections / veterinary*
  • Helicobacter pylori / genetics
  • Helicobacter pylori / isolation & purification*
  • Helicobacter pylori / pathogenicity
  • Humans
  • Macaca / microbiology*
  • Mice
  • Models, Molecular
  • Organoids / microbiology
  • Phenotype
  • Protein Conformation
  • Protein Interaction Mapping
  • Protein Serine-Threonine Kinases / metabolism
  • Protein Tyrosine Phosphatase, Non-Receptor Type 11 / metabolism
  • Recombinant Proteins / genetics
  • Sequence Alignment
  • Sequence Homology, Amino Acid
  • Species Specificity
  • Virulence
  • Zoonoses

Substances

  • Antigens, Bacterial
  • Bacterial Proteins
  • Cell Cycle Proteins
  • Recombinant Proteins
  • cagA protein, Helicobacter pylori
  • Mark2 protein, mouse
  • Protein Serine-Threonine Kinases
  • Protein Tyrosine Phosphatase, Non-Receptor Type 11
  • Ptpn11 protein, mouse