Abstract
beta-defensin 2 is produced by a variety of epithelial cell types in the body and exhibits potent antimicrobial activity against a variety of pathogens, including the bacteria that are most commonly associated with otitis media (OM). The human beta-defensin 2 (hBD-2) gene is an NF-kappa B regulated gene and a variety of proinflammatory stimuli can induce its expression. Although the presence of molecules of innate immunity such as lysozyme and lactoferrin has been demonstrated in the middle ear, to date there have been no reports on the expression of beta-defensin 2. In the present study, we demonstrate that beta-defensin 2 is expressed in the middle ear mucosa of humans and rats. We also show that it is expressed in a human middle ear epithelial cell line and that its expression is induced by proinflammatory stimuli such as interleukin 1 alpha (IL-1 alpha), tumor necrosis factor alpha (TNF-alpha), and lipopolysaccharide (LPS). Moreover, we demonstrate that the transcriptional activation of hBD-2 gene by IL-1 alpha is mediated through an Src-dependent Raf-MEK1/2-ERK signaling pathway.
Publication types
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Animals
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Cells, Cultured
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Ear, Middle / cytology
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Ear, Middle / drug effects
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Ear, Middle / metabolism*
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Epithelial Cells / drug effects
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Epithelial Cells / metabolism
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Humans
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Immunohistochemistry
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Interleukin-1 / pharmacology
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Lipopolysaccharides / pharmacology
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MAP Kinase Kinase 1
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MAP Kinase Kinase 2
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Mitogen-Activated Protein Kinase Kinases / metabolism*
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Mitogen-Activated Protein Kinases / metabolism*
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Models, Biological
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Mucous Membrane / drug effects
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Mucous Membrane / metabolism
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Protein Serine-Threonine Kinases / metabolism*
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Protein-Tyrosine Kinases / metabolism*
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Proto-Oncogene Proteins c-raf / metabolism*
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RNA, Messenger / genetics
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RNA, Messenger / metabolism
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Rats
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Signal Transduction
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Tumor Necrosis Factor-alpha / pharmacology
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Up-Regulation / drug effects
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beta-Defensins / genetics*
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src-Family Kinases / metabolism
Substances
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DEFB4A protein, human
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Interleukin-1
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Lipopolysaccharides
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RNA, Messenger
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Tumor Necrosis Factor-alpha
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beta-Defensins
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MAP2K2 protein, human
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Protein-Tyrosine Kinases
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src-Family Kinases
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Protein Serine-Threonine Kinases
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Proto-Oncogene Proteins c-raf
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Mitogen-Activated Protein Kinases
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MAP Kinase Kinase 1
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MAP Kinase Kinase 2
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MAP2K1 protein, human
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Mitogen-Activated Protein Kinase Kinases