Abstract
Increased subepithelial deposition of extracellular matrix proteins is a key feature in bronchial asthma. Matrix metalloproteinase-9 (MMP-9) is a proteolytic enzyme that degrades the extracellular matrix. Tenascin is an extracellular matrix glycoprotein that is abundant in thickened asthmatic subbasement membrane. The expression of MMP-9 and tenascin reflects disease activity in asthma and airway remodeling. The molecular mechanisms regulating the expression of these proteins remain unknown. Both MMP-9 and tenascin promoters contain an Ets binding site, suggesting control by Ets-1. Thus, we hypothesized that Ets-1 expression is increased in asthma and that it contributed to enhanced MMP-9 and tenascin expression. To test this hypothesis, we determined the expression of Ets-1 in bronchial biopsies obtained from asthmatic subjects and determined the expression of Ets-1, MMP-9, and tenascin by bronchial fibroblasts activated ex vivo. We observed that nuclear extracts from TNF-alpha-activated fibroblasts showed increased Ets-binding activity. In addition, TNF-alpha-activated fibroblasts had increased expression of Ets-1 mRNA and protein, which preceded an increase in MMP-9 and tenascin mRNA. Furthermore, treatment of fibroblasts with Ets-1 antisense oligonucleotides down-regulated TNF-alpha-induced Ets-1, MMP-9, and, to a lesser extent, tenascin protein expression or activity. Taken together, these data demonstrate that TNF-alpha increases MMP-9 and tenascin expression in bronchial fibroblasts via the transcription factor Ets-1, and suggest a role for Ets-1 in airway remodeling in asthma.
Publication types
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Adult
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Asthma / enzymology
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Asthma / immunology
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Asthma / metabolism*
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Bronchi / cytology
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Bronchi / enzymology
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Bronchi / immunology
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Bronchi / metabolism*
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Cells, Cultured
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DNA-Binding Proteins / antagonists & inhibitors
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DNA-Binding Proteins / metabolism
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Enzyme Induction / immunology
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Female
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Fibroblasts / enzymology
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Fibroblasts / immunology*
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Fibroblasts / metabolism*
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Fluorescein-5-isothiocyanate / metabolism
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Humans
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Male
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Matrix Metalloproteinase 9 / biosynthesis*
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Matrix Metalloproteinase 9 / genetics
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Oligonucleotides, Antisense / genetics
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Oligonucleotides, Antisense / metabolism
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Oligonucleotides, Antisense / pharmacology
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Protein Binding / immunology
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Proto-Oncogene Protein c-ets-1
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Proto-Oncogene Proteins / biosynthesis
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Proto-Oncogene Proteins / genetics
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Proto-Oncogene Proteins / metabolism
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Proto-Oncogene Proteins / physiology*
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Proto-Oncogene Proteins c-ets
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RNA, Messenger / biosynthesis
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Respiratory Mucosa / metabolism
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Tenascin / biosynthesis*
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Tenascin / genetics
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Thionucleotides / genetics
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Thionucleotides / metabolism
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Transcription Factors / biosynthesis
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Transcription Factors / genetics
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Transcription Factors / metabolism
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Transcription Factors / physiology*
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Transfection
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Tumor Necrosis Factor-alpha / pharmacology*
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Up-Regulation / physiology
Substances
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DNA-Binding Proteins
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ETS1 protein, human
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Oligonucleotides, Antisense
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Proto-Oncogene Protein c-ets-1
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Proto-Oncogene Proteins
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Proto-Oncogene Proteins c-ets
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RNA, Messenger
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Tenascin
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Thionucleotides
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Transcription Factors
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Tumor Necrosis Factor-alpha
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Matrix Metalloproteinase 9
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Fluorescein-5-isothiocyanate