Activation of oxidative stress-responsive signaling pathways in early splenotoxic response of aniline

Research output: Contribution to journalArticle

29 Citations (Scopus)

Abstract

Aniline exposure causes toxicity to the spleen, which leads to a variety of sarcomas, and fibrosis appears to be an important preneoplastic lesion. However, early molecular mechanisms in aniline-induced toxicity to the spleen are not known. Previously, we have shown that aniline exposure results in iron overload and induction of oxidative stress in the spleen, which can cause transcriptional upregulation of fibrogenic/inflammatory cytokines via activation of oxidative stress (OS)-responsive signaling pathways. To test this mechanism, male SD rats were treated with aniline (1mmol/kg/day via gavage) for 7days, an experimental condition that precedes the appearance of fibrosis. Significant increases in both NF-κB and AP-1 binding activity was observed in the nuclear extracts of splenocytes from aniline-treated rats as determined by ELISAs, and supported by Western blot data showing increases in p-IκBα, p-p65 and p-c-Jun. To understand the upstream signaling events which could account for the activation of NF-κB and AP-1, phosphorylation patterns of IκB kinases (IKKα and IKKβ) and mitogen-activated protein kinases (MAPKs) were pursued. Our data showed remarkable increases in both p-IKKα and p-IKKβ in the splenocytes from aniline-treated rats, suggesting their role in the phosphorylation of both IκBα and p65 subunits. Furthermore, aniline exposure led to activation of all three classes of MAPKs, as evident from increased phosphorylation of extracellular-signal-regulated kinase (ERK1/2), c-Jun N-terminal kinase (JNK1/2) and p38 MAPKs, which could potentially contribute to the observed activation of both AP-1 and NF-κB. Activation of upstream signaling molecules was also associated with simultaneous increases in gene transcription of cytokines IL-1, IL-6 and TNF-α. The observed sequence of events following aniline exposure could initiate a fibrogenic and/or tumorigenic response in the spleen.

Original languageEnglish (US)
Pages (from-to)227-234
Number of pages8
JournalToxicology and Applied Pharmacology
Volume230
Issue number2
DOIs
StatePublished - Jul 15 2008

Fingerprint

Oxidative stress
Oxidative Stress
Chemical activation
Phosphorylation
Transcription Factor AP-1
Spleen
Rats
Mitogen-Activated Protein Kinases
Toxicity
Fibrosis
Mitogen-Activated Protein Kinase 9
Cytokines
Iron Overload
aniline
Mitogen-Activated Protein Kinase 1
Extracellular Signal-Regulated MAP Kinases
p38 Mitogen-Activated Protein Kinases
Transcription
Interleukin-1
Sarcoma

Keywords

  • Aniline
  • AP-1
  • Cytokines
  • IKK
  • MAPK
  • NF-κB
  • Oxidative stress
  • Spleen

ASJC Scopus subject areas

  • Pharmacology
  • Toxicology

Cite this

@article{37c9f597aae34e41b8911dc074677e47,
title = "Activation of oxidative stress-responsive signaling pathways in early splenotoxic response of aniline",
abstract = "Aniline exposure causes toxicity to the spleen, which leads to a variety of sarcomas, and fibrosis appears to be an important preneoplastic lesion. However, early molecular mechanisms in aniline-induced toxicity to the spleen are not known. Previously, we have shown that aniline exposure results in iron overload and induction of oxidative stress in the spleen, which can cause transcriptional upregulation of fibrogenic/inflammatory cytokines via activation of oxidative stress (OS)-responsive signaling pathways. To test this mechanism, male SD rats were treated with aniline (1mmol/kg/day via gavage) for 7days, an experimental condition that precedes the appearance of fibrosis. Significant increases in both NF-κB and AP-1 binding activity was observed in the nuclear extracts of splenocytes from aniline-treated rats as determined by ELISAs, and supported by Western blot data showing increases in p-IκBα, p-p65 and p-c-Jun. To understand the upstream signaling events which could account for the activation of NF-κB and AP-1, phosphorylation patterns of IκB kinases (IKKα and IKKβ) and mitogen-activated protein kinases (MAPKs) were pursued. Our data showed remarkable increases in both p-IKKα and p-IKKβ in the splenocytes from aniline-treated rats, suggesting their role in the phosphorylation of both IκBα and p65 subunits. Furthermore, aniline exposure led to activation of all three classes of MAPKs, as evident from increased phosphorylation of extracellular-signal-regulated kinase (ERK1/2), c-Jun N-terminal kinase (JNK1/2) and p38 MAPKs, which could potentially contribute to the observed activation of both AP-1 and NF-κB. Activation of upstream signaling molecules was also associated with simultaneous increases in gene transcription of cytokines IL-1, IL-6 and TNF-α. The observed sequence of events following aniline exposure could initiate a fibrogenic and/or tumorigenic response in the spleen.",
keywords = "Aniline, AP-1, Cytokines, IKK, MAPK, NF-κB, Oxidative stress, Spleen",
author = "Jianling Wang and Gangduo Wang and Ghulam Ansari and M Khan",
year = "2008",
month = "7",
day = "15",
doi = "10.1016/j.taap.2008.02.022",
language = "English (US)",
volume = "230",
pages = "227--234",
journal = "Toxicology and Applied Pharmacology",
issn = "0041-008X",
publisher = "Academic Press Inc.",
number = "2",

}

TY - JOUR

T1 - Activation of oxidative stress-responsive signaling pathways in early splenotoxic response of aniline

AU - Wang, Jianling

AU - Wang, Gangduo

AU - Ansari, Ghulam

AU - Khan, M

PY - 2008/7/15

Y1 - 2008/7/15

N2 - Aniline exposure causes toxicity to the spleen, which leads to a variety of sarcomas, and fibrosis appears to be an important preneoplastic lesion. However, early molecular mechanisms in aniline-induced toxicity to the spleen are not known. Previously, we have shown that aniline exposure results in iron overload and induction of oxidative stress in the spleen, which can cause transcriptional upregulation of fibrogenic/inflammatory cytokines via activation of oxidative stress (OS)-responsive signaling pathways. To test this mechanism, male SD rats were treated with aniline (1mmol/kg/day via gavage) for 7days, an experimental condition that precedes the appearance of fibrosis. Significant increases in both NF-κB and AP-1 binding activity was observed in the nuclear extracts of splenocytes from aniline-treated rats as determined by ELISAs, and supported by Western blot data showing increases in p-IκBα, p-p65 and p-c-Jun. To understand the upstream signaling events which could account for the activation of NF-κB and AP-1, phosphorylation patterns of IκB kinases (IKKα and IKKβ) and mitogen-activated protein kinases (MAPKs) were pursued. Our data showed remarkable increases in both p-IKKα and p-IKKβ in the splenocytes from aniline-treated rats, suggesting their role in the phosphorylation of both IκBα and p65 subunits. Furthermore, aniline exposure led to activation of all three classes of MAPKs, as evident from increased phosphorylation of extracellular-signal-regulated kinase (ERK1/2), c-Jun N-terminal kinase (JNK1/2) and p38 MAPKs, which could potentially contribute to the observed activation of both AP-1 and NF-κB. Activation of upstream signaling molecules was also associated with simultaneous increases in gene transcription of cytokines IL-1, IL-6 and TNF-α. The observed sequence of events following aniline exposure could initiate a fibrogenic and/or tumorigenic response in the spleen.

AB - Aniline exposure causes toxicity to the spleen, which leads to a variety of sarcomas, and fibrosis appears to be an important preneoplastic lesion. However, early molecular mechanisms in aniline-induced toxicity to the spleen are not known. Previously, we have shown that aniline exposure results in iron overload and induction of oxidative stress in the spleen, which can cause transcriptional upregulation of fibrogenic/inflammatory cytokines via activation of oxidative stress (OS)-responsive signaling pathways. To test this mechanism, male SD rats were treated with aniline (1mmol/kg/day via gavage) for 7days, an experimental condition that precedes the appearance of fibrosis. Significant increases in both NF-κB and AP-1 binding activity was observed in the nuclear extracts of splenocytes from aniline-treated rats as determined by ELISAs, and supported by Western blot data showing increases in p-IκBα, p-p65 and p-c-Jun. To understand the upstream signaling events which could account for the activation of NF-κB and AP-1, phosphorylation patterns of IκB kinases (IKKα and IKKβ) and mitogen-activated protein kinases (MAPKs) were pursued. Our data showed remarkable increases in both p-IKKα and p-IKKβ in the splenocytes from aniline-treated rats, suggesting their role in the phosphorylation of both IκBα and p65 subunits. Furthermore, aniline exposure led to activation of all three classes of MAPKs, as evident from increased phosphorylation of extracellular-signal-regulated kinase (ERK1/2), c-Jun N-terminal kinase (JNK1/2) and p38 MAPKs, which could potentially contribute to the observed activation of both AP-1 and NF-κB. Activation of upstream signaling molecules was also associated with simultaneous increases in gene transcription of cytokines IL-1, IL-6 and TNF-α. The observed sequence of events following aniline exposure could initiate a fibrogenic and/or tumorigenic response in the spleen.

KW - Aniline

KW - AP-1

KW - Cytokines

KW - IKK

KW - MAPK

KW - NF-κB

KW - Oxidative stress

KW - Spleen

UR - http://www.scopus.com/inward/record.url?scp=45049086497&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=45049086497&partnerID=8YFLogxK

U2 - 10.1016/j.taap.2008.02.022

DO - 10.1016/j.taap.2008.02.022

M3 - Article

VL - 230

SP - 227

EP - 234

JO - Toxicology and Applied Pharmacology

JF - Toxicology and Applied Pharmacology

SN - 0041-008X

IS - 2

ER -