1. Helicobacter pylori CagA protein induces factors involved in the epithelial to mesenchymal transition (EMT) in infected gastric epithelial cells in an EPIYA- phosphorylation-dependent manner.
- Author
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Sougleri IS, Papadakos KS, Zadik MP, Mavri-Vavagianni M, Mentis AF, and Sgouras DN
- Subjects
- Amino Acid Motifs, Amino Acid Sequence, Animals, Antigens, Bacterial genetics, Bacterial Proteins genetics, Cell Line, Tumor, Epithelial Cells microbiology, Gastric Mucosa microbiology, Helicobacter Infections pathology, Host-Pathogen Interactions, Humans, Hyaluronan Receptors metabolism, Matrix Metalloproteinase 3 metabolism, Molecular Sequence Data, Phosphorylation, Vimentin metabolism, Antigens, Bacterial metabolism, Bacterial Proteins metabolism, Epithelial Cells metabolism, Epithelial-Mesenchymal Transition, Gastric Mucosa metabolism, Helicobacter Infections metabolism, Helicobacter pylori pathogenicity
- Abstract
As a result of Helicobacter pylori adhesion to gastric epithelial cells, the bacterial effector cytotoxin-associated gene A (CagA) is translocated intracellularly, and after hierarchical tyrosine phosphorylation on multiple EPIYA motifs, de-regulates cellular polarity and contributes to induction of an elongation and scattering phenotype that resembles the epithelial to mesenchymal transition (EMT). Stromelysin-1/matrix metalloproteinase-3 (MMP-3) has been reported to induce a sequence of molecular alterations leading to stable EMT transition and carcinogenesis in epithelial cells. To identify the putative role of CagA protein in MMP-3 induction, we exploited an experimental H. pylori infection system in gastric epithelial cell lines. We utilized isogenic mutants expressing CagA protein with variable numbers of EPIYA and phosphorylation-deficient EPIFA motifs, as well as cagA knockout and translocation-deficient cagE knockout strains. Increased levels of MMP-3 transcriptional activation were demonstrated by quantitative real time-PCR for strains with more than two terminal EPIYA phosphorylation motifs in CagA. MMP-3 expression in total cell lysates and the corresponding culture supernatants was associated with CagA expression and translocation and was dependent on CagA phosphorylation. A CagA EPIYA phosphorylation-dependent increase in gelatinase and caseinolytic activity was also detected in culture supernatants by zymography. A significant increase in the transcriptional activity of the mesenchymal markers Vimentin, Snail and ZEB1 and the stem cell marker CD44 was observed in the case of CagA containing phosphorylation-functional EPIYA motifs. Our data suggest that CagA protein induces EMT through EPIYA phosphorylation-dependent up-regulation of MMP-3. Moreover, no significant increase in EMT and stem cell markers was observed following infection with H. pylori strains that cannot effectively translocate CagA protein., (© 2015 FEBS.)
- Published
- 2016
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