Effects of mechanistically distinct NF-κB inhibitors on glial inducible nitric-oxide synthase expression

Randall Davis, Alma C. Sanchez, Daniel J. Lindley, Simon C. Williams, Peter J. Syapin

Research output: Contribution to journalArticle

38 Citations (Scopus)

Abstract

Nuclear factor (NF)-κB is an important regulator of inflammatory gene expression. Transcriptional regulation of Nos2, the inducible nitric-oxide synthase (iNOS) gene, is complex and not fully understood, but appears to be regulated in part by NF-κB. To further understand the role of NF-κB in Nos2 expression, we compared three functionally distinct NF-κB inhibitors on NF-κB transactivation and iNOS induction by rat C6 glial cells. Cytokine-induced activation of a consensus NF-κB-reporter gene was concentration-dependently inhibited by BAY 11-7082, MG-132, and helenalin. The rank order of potency was MG-132 > helenalin > BAY 11-7082, with low concentrations of helenalin stimulating reporter gene activity. Cytokine-stimulated iNOS expression, measured by nitrite accumulation and in vitro l-citrulline production, was similarly reduced by exposing C6 cells to the NF-κB inhibitors. Surprisingly, activation of Nos2-reporter gene constructs containing the proximal 188 bp (containing one κB site) or proximal 94 bp (no κB site) of the rat promoter also was inhibited with the same rank order of potency. Interestingly, low concentrations of helenalin increased activity of both promoter constructs, while BAY 11-7082 poorly inhibited the 94-bp activity. This is the first report describing BAY 11-7082 and helenalin effects on iNOS expression in astroglia. Given the reported mechanism of actions for these inhibitors, cytokine-induced glial iNOS expression appears more sensitive to disruption of proteasome degradation and p65 function than modulation of IκB phosphorylation. These findings may foster the design of therapeutic agents aimed at NF-κB-associated pathways involved in neuroinflammation, especially iNOS expression.

Original languageEnglish
Pages (from-to)200-209
Number of pages10
JournalNitric Oxide - Biology and Chemistry
Volume12
Issue number4
DOIs
StatePublished - 1 Jun 2005

Fingerprint

Nitric Oxide Synthase Type II
Neuroglia
Genes
Reporter Genes
Cytokines
Rats
Chemical activation
Citrulline
Phosphorylation
Proteasome Endopeptidase Complex
Regulator Genes
Nitrites
Gene expression
Astrocytes
Transcriptional Activation
Modulation
helenalin
Gene Expression
Degradation
3-(4-methylphenylsulfonyl)-2-propenenitrile

Keywords

  • Astrocyte
  • BAY 11-7082
  • Gene regulation
  • Helenalin
  • MG-132
  • NF-κB
  • Neuroinflammation

Cite this

Davis, Randall ; Sanchez, Alma C. ; Lindley, Daniel J. ; Williams, Simon C. ; Syapin, Peter J. / Effects of mechanistically distinct NF-κB inhibitors on glial inducible nitric-oxide synthase expression. In: Nitric Oxide - Biology and Chemistry. 2005 ; Vol. 12, No. 4. pp. 200-209.
@article{fcf4513ca0fc48648afbb73b73f805d7,
title = "Effects of mechanistically distinct NF-κB inhibitors on glial inducible nitric-oxide synthase expression",
abstract = "Nuclear factor (NF)-κB is an important regulator of inflammatory gene expression. Transcriptional regulation of Nos2, the inducible nitric-oxide synthase (iNOS) gene, is complex and not fully understood, but appears to be regulated in part by NF-κB. To further understand the role of NF-κB in Nos2 expression, we compared three functionally distinct NF-κB inhibitors on NF-κB transactivation and iNOS induction by rat C6 glial cells. Cytokine-induced activation of a consensus NF-κB-reporter gene was concentration-dependently inhibited by BAY 11-7082, MG-132, and helenalin. The rank order of potency was MG-132 > helenalin > BAY 11-7082, with low concentrations of helenalin stimulating reporter gene activity. Cytokine-stimulated iNOS expression, measured by nitrite accumulation and in vitro l-citrulline production, was similarly reduced by exposing C6 cells to the NF-κB inhibitors. Surprisingly, activation of Nos2-reporter gene constructs containing the proximal 188 bp (containing one κB site) or proximal 94 bp (no κB site) of the rat promoter also was inhibited with the same rank order of potency. Interestingly, low concentrations of helenalin increased activity of both promoter constructs, while BAY 11-7082 poorly inhibited the 94-bp activity. This is the first report describing BAY 11-7082 and helenalin effects on iNOS expression in astroglia. Given the reported mechanism of actions for these inhibitors, cytokine-induced glial iNOS expression appears more sensitive to disruption of proteasome degradation and p65 function than modulation of IκB phosphorylation. These findings may foster the design of therapeutic agents aimed at NF-κB-associated pathways involved in neuroinflammation, especially iNOS expression.",
keywords = "Astrocyte, BAY 11-7082, Gene regulation, Helenalin, MG-132, NF-κB, Neuroinflammation",
author = "Randall Davis and Sanchez, {Alma C.} and Lindley, {Daniel J.} and Williams, {Simon C.} and Syapin, {Peter J.}",
year = "2005",
month = "6",
day = "1",
doi = "10.1016/j.niox.2005.04.005",
language = "English",
volume = "12",
pages = "200--209",
journal = "Nitric Oxide - Biology and Chemistry",
issn = "1089-8603",
publisher = "Academic Press Inc.",
number = "4",

}

Effects of mechanistically distinct NF-κB inhibitors on glial inducible nitric-oxide synthase expression. / Davis, Randall; Sanchez, Alma C.; Lindley, Daniel J.; Williams, Simon C.; Syapin, Peter J.

In: Nitric Oxide - Biology and Chemistry, Vol. 12, No. 4, 01.06.2005, p. 200-209.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Effects of mechanistically distinct NF-κB inhibitors on glial inducible nitric-oxide synthase expression

AU - Davis, Randall

AU - Sanchez, Alma C.

AU - Lindley, Daniel J.

AU - Williams, Simon C.

AU - Syapin, Peter J.

PY - 2005/6/1

Y1 - 2005/6/1

N2 - Nuclear factor (NF)-κB is an important regulator of inflammatory gene expression. Transcriptional regulation of Nos2, the inducible nitric-oxide synthase (iNOS) gene, is complex and not fully understood, but appears to be regulated in part by NF-κB. To further understand the role of NF-κB in Nos2 expression, we compared three functionally distinct NF-κB inhibitors on NF-κB transactivation and iNOS induction by rat C6 glial cells. Cytokine-induced activation of a consensus NF-κB-reporter gene was concentration-dependently inhibited by BAY 11-7082, MG-132, and helenalin. The rank order of potency was MG-132 > helenalin > BAY 11-7082, with low concentrations of helenalin stimulating reporter gene activity. Cytokine-stimulated iNOS expression, measured by nitrite accumulation and in vitro l-citrulline production, was similarly reduced by exposing C6 cells to the NF-κB inhibitors. Surprisingly, activation of Nos2-reporter gene constructs containing the proximal 188 bp (containing one κB site) or proximal 94 bp (no κB site) of the rat promoter also was inhibited with the same rank order of potency. Interestingly, low concentrations of helenalin increased activity of both promoter constructs, while BAY 11-7082 poorly inhibited the 94-bp activity. This is the first report describing BAY 11-7082 and helenalin effects on iNOS expression in astroglia. Given the reported mechanism of actions for these inhibitors, cytokine-induced glial iNOS expression appears more sensitive to disruption of proteasome degradation and p65 function than modulation of IκB phosphorylation. These findings may foster the design of therapeutic agents aimed at NF-κB-associated pathways involved in neuroinflammation, especially iNOS expression.

AB - Nuclear factor (NF)-κB is an important regulator of inflammatory gene expression. Transcriptional regulation of Nos2, the inducible nitric-oxide synthase (iNOS) gene, is complex and not fully understood, but appears to be regulated in part by NF-κB. To further understand the role of NF-κB in Nos2 expression, we compared three functionally distinct NF-κB inhibitors on NF-κB transactivation and iNOS induction by rat C6 glial cells. Cytokine-induced activation of a consensus NF-κB-reporter gene was concentration-dependently inhibited by BAY 11-7082, MG-132, and helenalin. The rank order of potency was MG-132 > helenalin > BAY 11-7082, with low concentrations of helenalin stimulating reporter gene activity. Cytokine-stimulated iNOS expression, measured by nitrite accumulation and in vitro l-citrulline production, was similarly reduced by exposing C6 cells to the NF-κB inhibitors. Surprisingly, activation of Nos2-reporter gene constructs containing the proximal 188 bp (containing one κB site) or proximal 94 bp (no κB site) of the rat promoter also was inhibited with the same rank order of potency. Interestingly, low concentrations of helenalin increased activity of both promoter constructs, while BAY 11-7082 poorly inhibited the 94-bp activity. This is the first report describing BAY 11-7082 and helenalin effects on iNOS expression in astroglia. Given the reported mechanism of actions for these inhibitors, cytokine-induced glial iNOS expression appears more sensitive to disruption of proteasome degradation and p65 function than modulation of IκB phosphorylation. These findings may foster the design of therapeutic agents aimed at NF-κB-associated pathways involved in neuroinflammation, especially iNOS expression.

KW - Astrocyte

KW - BAY 11-7082

KW - Gene regulation

KW - Helenalin

KW - MG-132

KW - NF-κB

KW - Neuroinflammation

UR - http://www.scopus.com/inward/record.url?scp=19544393559&partnerID=8YFLogxK

U2 - 10.1016/j.niox.2005.04.005

DO - 10.1016/j.niox.2005.04.005

M3 - Article

C2 - 15890551

AN - SCOPUS:19544393559

VL - 12

SP - 200

EP - 209

JO - Nitric Oxide - Biology and Chemistry

JF - Nitric Oxide - Biology and Chemistry

SN - 1089-8603

IS - 4

ER -