Helicobacter pylori adhesin HopQ engages in a virulence-enhancing interaction with human CEACAMs

Nat Microbiol. 2016 Oct 17:2:16189. doi: 10.1038/nmicrobiol.2016.189.

Abstract

Helicobacter pylori specifically colonizes the human gastric epithelium and is the major causative agent for ulcer disease and gastric cancer development. Here, we identify members of the carcinoembryonic antigen-related cell adhesion molecule (CEACAM) family as receptors of H. pylori and show that HopQ is the surface-exposed adhesin that specifically binds human CEACAM1, CEACAM3, CEACAM5 and CEACAM6. HopQ-CEACAM binding is glycan-independent and targeted to the N-domain. H. pylori binding induces CEACAM1-mediated signalling, and the HopQ-CEACAM1 interaction enables translocation of the virulence factor CagA into host cells and enhances the release of pro-inflammatory mediators such as interleukin-8. Based on the crystal structure of HopQ, we found that a β-hairpin insertion (HopQ-ID) in HopQ's extracellular 3+4 helix bundle domain is important for CEACAM binding. A peptide derived from this domain competitively inhibits HopQ-mediated activation of the Cag virulence pathway, as genetic or antibody-mediated abrogation of the HopQ function shows. Together, our data suggest the HopQ-CEACAM1 interaction to be a potentially promising novel therapeutic target to combat H. pylori-associated diseases.

MeSH terms

  • Adhesins, Bacterial / chemistry
  • Adhesins, Bacterial / metabolism*
  • Antigens, Bacterial / metabolism
  • Bacterial Adhesion*
  • Bacterial Proteins / metabolism
  • Cell Adhesion Molecules / metabolism*
  • Cell Line
  • Crystallography, X-Ray
  • Helicobacter pylori / pathogenicity*
  • Helicobacter pylori / physiology*
  • Host-Pathogen Interactions*
  • Humans
  • Interleukin-8 / metabolism
  • Protein Binding
  • Protein Conformation
  • Protein Transport
  • Virulence

Substances

  • Adhesins, Bacterial
  • Antigens, Bacterial
  • Bacterial Proteins
  • CXCL8 protein, human
  • Cell Adhesion Molecules
  • Interleukin-8
  • adhesin, helicobacter
  • cagA protein, Helicobacter pylori