CD44 plays a functional role in Helicobacter pylori-induced epithelial cell proliferation

PLoS Pathog. 2015 Feb 6;11(2):e1004663. doi: 10.1371/journal.ppat.1004663. eCollection 2015 Feb.

Abstract

The cytotoxin-associated gene (Cag) pathogenicity island is a strain-specific constituent of Helicobacter pylori (H. pylori) that augments cancer risk. CagA translocates into the cytoplasm where it stimulates cell signaling through the interaction with tyrosine kinase c-Met receptor, leading cellular proliferation. Identified as a potential gastric stem cell marker, cluster-of-differentiation (CD) CD44 also acts as a co-receptor for c-Met, but whether it plays a functional role in H. pylori-induced epithelial proliferation is unknown. We tested the hypothesis that CD44 plays a functional role in H. pylori-induced epithelial cell proliferation. To assay changes in gastric epithelial cell proliferation in relation to the direct interaction with H. pylori, human- and mouse-derived gastric organoids were infected with the G27 H. pylori strain or a mutant G27 strain bearing cagA deletion (∆CagA::cat). Epithelial proliferation was quantified by EdU immunostaining. Phosphorylation of c-Met was analyzed by immunoprecipitation followed by Western blot analysis for expression of CD44 and CagA. H. pylori infection of both mouse- and human-derived gastric organoids induced epithelial proliferation that correlated with c-Met phosphorylation. CagA and CD44 co-immunoprecipitated with phosphorylated c-Met. The formation of this complex did not occur in organoids infected with ∆CagA::cat. Epithelial proliferation in response to H. pylori infection was lost in infected organoids derived from CD44-deficient mouse stomachs. Human-derived fundic gastric organoids exhibited an induction in proliferation when infected with H. pylori that was not seen in organoids pre-treated with a peptide inhibitor specific to CD44. In the well-established Mongolian gerbil model of gastric cancer, animals treated with CD44 peptide inhibitor Pep1, resulted in the inhibition of H. pylori-induced proliferation and associated atrophic gastritis. The current study reports a unique approach to study H. pylori interaction with the human gastric epithelium. Here, we show that CD44 plays a functional role in H. pylori-induced epithelial cell proliferation.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antigens, Bacterial / genetics
  • Antigens, Bacterial / immunology
  • Bacterial Proteins / genetics
  • Bacterial Proteins / immunology
  • Cell Proliferation*
  • Disease Models, Animal
  • Epithelial Cells / immunology*
  • Epithelial Cells / pathology
  • Gastric Fundus / immunology
  • Gastric Fundus / microbiology
  • Gastric Mucosa / immunology*
  • Gastric Mucosa / microbiology
  • Gene Deletion
  • Helicobacter Infections / genetics
  • Helicobacter Infections / immunology*
  • Helicobacter Infections / pathology
  • Helicobacter pylori / genetics
  • Helicobacter pylori / immunology*
  • Helicobacter pylori / pathogenicity
  • Humans
  • Hyaluronan Receptors / immunology*
  • Mice
  • Receptor Protein-Tyrosine Kinases / immunology

Substances

  • Antigens, Bacterial
  • Bacterial Proteins
  • Cd44 protein, mouse
  • Hyaluronan Receptors
  • cagA protein, Helicobacter pylori
  • RON protein
  • Receptor Protein-Tyrosine Kinases