20 Citations (Scopus)

Abstract

NF-κB repressing factor (NRF), a nuclear inhibitor of NF-κB, is constitutively expressed and is implicated in the basal silencing of specific NF-κB targeting genes, including IFN-β, IL-8/CXCL8, and iNOS. Little is known about the regulation of NRF and its role in response to stimuli. Airway smooth muscle (ASM) is a rich source of inflammatory mediators that may regulate the development and progression of airway inflammation. We have previously reported that NE activates NF-κB in primary human ASM (hASM), leading to induction of TGF-β1. In this study, we describe that, instead of inducing the NF-κB response gene IL-8/CXCL8, NE suppressed IL-8/CXCL8 release and mRNA expression in hASM cells. Transcriptional blockade studies using actinomycin D revealed a similar degradation rate of IL-8/CXCL8 mRNA in the presence or absence of NE, suggesting an involvement at the transcription level. Mechanistically, the NE repressive effect was mediated by inducing NRF, as shown by RT-PCR and Western blotting, which was subsequently recruited to the native IL-8/CXCL8 promoter leading to removal of RNA polymerase II from the promoter, as demonstrated by chromatin immunoprecipitation assays. Knockdown of NRF by small interfering RNA prevented NE-induced suppression of IL-8/CXCL8 expression. In contrast, NE did not induce NRF expression in A549 and Beas-2B cells, where NE only stimulates NF-κB activation and IL-8/CXCL8 induction. Forced expression of NRF in A549 cells by an NRF expression plasmid suppressed IL-8/CXCL8 expression. Hence, we describe a novel negative regulatory mechanism of NE-induced NRF, which is restricted to hASM and mediates the suppression of IL-8/CXCL8 expression.

Original languageEnglish
Pages (from-to)411-420
Number of pages10
JournalJournal of Immunology
Volume183
Issue number1
DOIs
Publication statusPublished - Jul 1 2009

Fingerprint

Leukocyte Elastase
Interleukin-8
Smooth Muscle Myocytes
Smooth Muscle
3'-(1-butylphosphoryl)adenosine
Messenger RNA
Gene Targeting
RNA Polymerase II
Chromatin Immunoprecipitation
Dactinomycin
Small Interfering RNA
Plasmids
Western Blotting
Inflammation
Polymerase Chain Reaction

ASJC Scopus subject areas

  • Immunology
  • Medicine(all)

Cite this

@article{5883543efcf14571941118f65d61e420,
title = "Neutrophil elastase represses IL-8/CXCL8 synthesis in human airway smooth muscle cells through induction of NF-κB repressing factor",
abstract = "NF-κB repressing factor (NRF), a nuclear inhibitor of NF-κB, is constitutively expressed and is implicated in the basal silencing of specific NF-κB targeting genes, including IFN-β, IL-8/CXCL8, and iNOS. Little is known about the regulation of NRF and its role in response to stimuli. Airway smooth muscle (ASM) is a rich source of inflammatory mediators that may regulate the development and progression of airway inflammation. We have previously reported that NE activates NF-κB in primary human ASM (hASM), leading to induction of TGF-β1. In this study, we describe that, instead of inducing the NF-κB response gene IL-8/CXCL8, NE suppressed IL-8/CXCL8 release and mRNA expression in hASM cells. Transcriptional blockade studies using actinomycin D revealed a similar degradation rate of IL-8/CXCL8 mRNA in the presence or absence of NE, suggesting an involvement at the transcription level. Mechanistically, the NE repressive effect was mediated by inducing NRF, as shown by RT-PCR and Western blotting, which was subsequently recruited to the native IL-8/CXCL8 promoter leading to removal of RNA polymerase II from the promoter, as demonstrated by chromatin immunoprecipitation assays. Knockdown of NRF by small interfering RNA prevented NE-induced suppression of IL-8/CXCL8 expression. In contrast, NE did not induce NRF expression in A549 and Beas-2B cells, where NE only stimulates NF-κB activation and IL-8/CXCL8 induction. Forced expression of NRF in A549 cells by an NRF expression plasmid suppressed IL-8/CXCL8 expression. Hence, we describe a novel negative regulatory mechanism of NE-induced NRF, which is restricted to hASM and mediates the suppression of IL-8/CXCL8 expression.",
author = "Ho, {Shu Chuan} and Lee, {Kang Yun} and Chan, {Yao Fei} and Kuo, {Lu Wei} and Kazuhiro Ito and Adcock, {Ian M.} and Chen, {Bing Chang} and Sheu, {Joen Rong} and Lin, {Chien Huang} and Kuo, {Han Pin}",
year = "2009",
month = "7",
day = "1",
doi = "10.4049/jimmunol.0803729",
language = "English",
volume = "183",
pages = "411--420",
journal = "Journal of Immunology",
issn = "0022-1767",
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TY - JOUR

T1 - Neutrophil elastase represses IL-8/CXCL8 synthesis in human airway smooth muscle cells through induction of NF-κB repressing factor

AU - Ho, Shu Chuan

AU - Lee, Kang Yun

AU - Chan, Yao Fei

AU - Kuo, Lu Wei

AU - Ito, Kazuhiro

AU - Adcock, Ian M.

AU - Chen, Bing Chang

AU - Sheu, Joen Rong

AU - Lin, Chien Huang

AU - Kuo, Han Pin

PY - 2009/7/1

Y1 - 2009/7/1

N2 - NF-κB repressing factor (NRF), a nuclear inhibitor of NF-κB, is constitutively expressed and is implicated in the basal silencing of specific NF-κB targeting genes, including IFN-β, IL-8/CXCL8, and iNOS. Little is known about the regulation of NRF and its role in response to stimuli. Airway smooth muscle (ASM) is a rich source of inflammatory mediators that may regulate the development and progression of airway inflammation. We have previously reported that NE activates NF-κB in primary human ASM (hASM), leading to induction of TGF-β1. In this study, we describe that, instead of inducing the NF-κB response gene IL-8/CXCL8, NE suppressed IL-8/CXCL8 release and mRNA expression in hASM cells. Transcriptional blockade studies using actinomycin D revealed a similar degradation rate of IL-8/CXCL8 mRNA in the presence or absence of NE, suggesting an involvement at the transcription level. Mechanistically, the NE repressive effect was mediated by inducing NRF, as shown by RT-PCR and Western blotting, which was subsequently recruited to the native IL-8/CXCL8 promoter leading to removal of RNA polymerase II from the promoter, as demonstrated by chromatin immunoprecipitation assays. Knockdown of NRF by small interfering RNA prevented NE-induced suppression of IL-8/CXCL8 expression. In contrast, NE did not induce NRF expression in A549 and Beas-2B cells, where NE only stimulates NF-κB activation and IL-8/CXCL8 induction. Forced expression of NRF in A549 cells by an NRF expression plasmid suppressed IL-8/CXCL8 expression. Hence, we describe a novel negative regulatory mechanism of NE-induced NRF, which is restricted to hASM and mediates the suppression of IL-8/CXCL8 expression.

AB - NF-κB repressing factor (NRF), a nuclear inhibitor of NF-κB, is constitutively expressed and is implicated in the basal silencing of specific NF-κB targeting genes, including IFN-β, IL-8/CXCL8, and iNOS. Little is known about the regulation of NRF and its role in response to stimuli. Airway smooth muscle (ASM) is a rich source of inflammatory mediators that may regulate the development and progression of airway inflammation. We have previously reported that NE activates NF-κB in primary human ASM (hASM), leading to induction of TGF-β1. In this study, we describe that, instead of inducing the NF-κB response gene IL-8/CXCL8, NE suppressed IL-8/CXCL8 release and mRNA expression in hASM cells. Transcriptional blockade studies using actinomycin D revealed a similar degradation rate of IL-8/CXCL8 mRNA in the presence or absence of NE, suggesting an involvement at the transcription level. Mechanistically, the NE repressive effect was mediated by inducing NRF, as shown by RT-PCR and Western blotting, which was subsequently recruited to the native IL-8/CXCL8 promoter leading to removal of RNA polymerase II from the promoter, as demonstrated by chromatin immunoprecipitation assays. Knockdown of NRF by small interfering RNA prevented NE-induced suppression of IL-8/CXCL8 expression. In contrast, NE did not induce NRF expression in A549 and Beas-2B cells, where NE only stimulates NF-κB activation and IL-8/CXCL8 induction. Forced expression of NRF in A549 cells by an NRF expression plasmid suppressed IL-8/CXCL8 expression. Hence, we describe a novel negative regulatory mechanism of NE-induced NRF, which is restricted to hASM and mediates the suppression of IL-8/CXCL8 expression.

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