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CagA phosphorylation-dependent MMP-9 expression in gastric epithelial cells

 Young-Hee Nam  ;  Eunju Ryu  ;  Doyeon Lee  ;  Hyun Jae Shim  ;  Yong Chan Lee  ;  Seung-Taek Lee 
 HELICOBACTER, Vol.16(4) : 276-283, 2011 
Journal Title
Issue Date
Antigens, Bacterial/metabolism* ; Bacterial Proteins/metabolism* ; Cell Line ; Epithelial Cells/enzymology* ; Epithelial Cells/microbiology* ; Gastric Mucosa/microbiology ; Gastric Mucosa/pathology* ; Gene Expression* ; Helicobacter pylori/pathogenicity* ; Host-Pathogen Interactions ; Humans ; Matrix Metalloproteinase 9/secretion* ; Protein Tyrosine Phosphatase, Non-Receptor Type 11/metabolism ; src-Family Kinases/metabolism
CagA ; ERK ; Helicobacter pylori ; MMP-9 ; NF-jB ; tyrosine phosphorylation
BACKGROUND: Infection of cagA-positive Helicobacter pylori is associated with increased expression of MMPs in gastric epithelial cells. The role of phosphorylated CagA in the induction of MMP-9, a protease-degrading basement membrane, in gastric epithelial cells has not been clearly defined yet. The aim of this study is to analyze whether the presence of CagA and its phosphorylation status play a role in increased expression of MMP-9 in gastric epithelial cells.

MATERIALS AND METHODS: Induction of MMP-9 secretion was analyzed in gastric epithelial AGS cells harboring CagA with or without EPIYA motif, which is injected by H. pylori or ectopically expressed. In addition, signaling pathways involved in the CagA-dependent MMP-9 production have been studied.

RESULTS: The 147C strain of H. pylori expressing tyrosine-phosphorylated CagA (EPIYA present) induced higher MMP-9 secretion by AGS cells than the 147A strain expressing non-tyrosine-phosphorylated CagA (EPIYA absent). In addition, in bacteria-free CagA-inducible AGS cells, expression of wild-type CagA induced more MMP-9 secretion than phosphorylation-resistant CagA. Inhibition of CagA phosphorylation by the Src family kinase inhibitor PP1 downregulated CagA-mediated MMP-9 secretion. Knockdown of SHP-2 phosphatase dramatically reduced MMP-9 secretion. ERK inhibitors, PD98059 and U0126, and NF-κB pathway inhibitors, sulfasalazine and N-acetyl-l-cysteine, also inhibited MMP-9 expression.

CONCLUSION: These results support a model whereby the EPIYA motif of CagA is phosphorylated by Src family kinases in gastric epithelial cells, which initiates activation of SHP-2. In addition, they suggest that the resultant activation of ERK pathway along with CagA-dependent NF-κB activation is critical for the induction of MMP-9 secretion.
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1. College of Medicine (의과대학) > Dept. of Internal Medicine (내과학교실) > 1. Journal Papers
Yonsei Authors
Lee, Yong Chan(이용찬) ORCID logo https://orcid.org/0000-0001-8800-6906
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