Abstract
Cytotoxic necrotizing factor type 1 (CNF1) from Escherichia coli activates the small GTP-binding proteins of the Rho family (Rho, Rac, and Cdc42) by catalyzing their deamidation at a specific glutamine residue. Since RhoA, Rac, and Cdc42 play a pivotal role in cell migration during the early phase of wound repair, we investigated whether CNF1 was able to interfere with wound healing in intestinal epithelial monolayers (T84 cells). After mechanical injury, we found that CNF1 blocks epithelial wound repair within 48 h. This effect was characterized by cell elongation and filopodium formation on the leading edge, in association with permanent phosphorylation of the focal adhesion kinase (FAK) via Rho activation. Moreover, inhibition of Rho kinase with Y-27632 decreased CNF1-mediated permanent FAK phosphorylation, leading to complete restitution of wound repair within 24 h. In addition, we found that CNF1 induced upregulation of mitogen-activated protein kinases (MAPK) activation. Moreover, activation of Rac and MAPK by CNF1 increased matrix metalloproteinase 9 expression in wounded T84 monolayers. Taken together, these results provide evidence that CNF1 strongly impairs intestinal epithelial wound healing.
MeSH terms
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Amides / pharmacology
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Bacterial Toxins / pharmacology*
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Cell Line, Tumor
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Cytotoxins / pharmacology*
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Enzyme Activation / drug effects
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Epithelial Cells / drug effects
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Epithelial Cells / metabolism
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Epithelium / drug effects*
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Epithelium / injuries*
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Epithelium / physiology
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Escherichia coli Proteins*
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Escherichia coli*
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Focal Adhesion Kinase 1
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Focal Adhesion Protein-Tyrosine Kinases
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Humans
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Intestines / drug effects*
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Intestines / injuries*
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Intestines / microbiology
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Intestines / physiology
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Matrix Metalloproteinase 9 / metabolism
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Mitogen-Activated Protein Kinases / metabolism
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Phosphorylation / drug effects
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Protein-Tyrosine Kinases / metabolism
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Pyridines / pharmacology
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Wound Healing / drug effects*
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Wound Healing / physiology
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cdc42 GTP-Binding Protein / metabolism
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rac GTP-Binding Proteins / metabolism
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rhoA GTP-Binding Protein / antagonists & inhibitors
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rhoA GTP-Binding Protein / metabolism
Substances
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Amides
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Bacterial Toxins
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Cytotoxins
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Escherichia coli Proteins
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Pyridines
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cytotoxic necrotizing factor type 1
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Y 27632
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Protein-Tyrosine Kinases
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Focal Adhesion Kinase 1
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Focal Adhesion Protein-Tyrosine Kinases
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PTK2 protein, human
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Mitogen-Activated Protein Kinases
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Matrix Metalloproteinase 9
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cdc42 GTP-Binding Protein
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rac GTP-Binding Proteins
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rhoA GTP-Binding Protein