Abstract
In the current study, we examined the role of CD14 in regulating LPS activation of corneal epithelial cells and Pseudomonas aeruginosa corneal infection. Our findings demonstrate that LPS induces Toll-like receptor 4 (TLR4) internalization in corneal epithelial cells and that blocking with anti-CD14 selectively inhibits TLR4 endocytosis, spleen tyrosine kinase (Syk) and IRF3 phosphorylation, and production of CCL5/RANTES and IFN-β, but not IL-8. Using a murine model of P. aeruginosa corneal infection, we show that although infected CD14(-/-) corneas produce less CCL5, they exhibit significantly increased CXC chemokine production, neutrophil recruitment to the corneal stroma, and bacterial clearance than C57BL/6 mice. We conclude that CD14 has a critical role in mediating TLR4 signaling through IRF3 in resident corneal epithelial cells and macrophages and thereby modulates TLR4 cell surface activation of the MyD88/NF-κB/AP-1 pathway and production of CXC chemokines and neutrophil infiltration to infected tissues.
Keywords:
Cornea; Epithelial Cell; Inflammation; Lipopolysaccharide (LPS); Neutrophil; Pseudomonas aeruginosa; Toll-like Receptors (TLRs).
Publication types
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Research Support, N.I.H., Extramural
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Research Support, Non-U.S. Gov't
MeSH terms
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Animals
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Blotting, Western
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Cell Line
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Cells, Cultured
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Chemokine CCL5 / immunology
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Chemokine CCL5 / metabolism
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Cornea / cytology
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Cornea / immunology
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Cornea / microbiology
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Endocytosis / drug effects
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Endocytosis / immunology
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Epithelial Cells / immunology*
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Epithelial Cells / metabolism
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Epithelial Cells / microbiology
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Host-Pathogen Interactions / immunology
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Humans
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Interferon Regulatory Factor-3 / immunology*
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Interferon Regulatory Factor-3 / metabolism
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Interferon-beta / immunology
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Interferon-beta / metabolism
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Intracellular Signaling Peptides and Proteins / immunology*
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Intracellular Signaling Peptides and Proteins / metabolism
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Lipopolysaccharide Receptors / genetics
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Lipopolysaccharide Receptors / immunology*
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Lipopolysaccharide Receptors / metabolism
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Lipopolysaccharides / immunology
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Lipopolysaccharides / pharmacology
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Mice
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Mice, Inbred C57BL
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Mice, Knockout
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Neutrophil Infiltration / drug effects
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Neutrophil Infiltration / immunology
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Phosphorylation / drug effects
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Phosphorylation / immunology
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Protein-Tyrosine Kinases / immunology*
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Protein-Tyrosine Kinases / metabolism
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Pseudomonas Infections / immunology
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Pseudomonas Infections / microbiology
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Pseudomonas aeruginosa / immunology
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Pseudomonas aeruginosa / physiology
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Syk Kinase
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Toll-Like Receptor 4 / immunology*
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Toll-Like Receptor 4 / metabolism
Substances
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Chemokine CCL5
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Interferon Regulatory Factor-3
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Intracellular Signaling Peptides and Proteins
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Lipopolysaccharide Receptors
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Lipopolysaccharides
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Toll-Like Receptor 4
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Interferon-beta
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Protein-Tyrosine Kinases
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SYK protein, human
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Syk Kinase
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Syk protein, mouse