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, Ioanna S., Papadakos, Konstantinos S., Zadik, Mairi P., Mavri‐Vavagianni, Mary, Mentis, Andreas F., and Sgouras, Dionyssios N.
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HELICOBACTER pylori ,CYTOTOXINS ,BACTERIAL proteins ,EPITHELIAL cells ,PHOSPHORYLATION ,MATRIX metalloproteinases - 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. [ABSTRACT FROM AUTHOR]
- Published
- 2016
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