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Oxidative stress enhances toll-like receptor 3 response to double-stranded RNA in airway epithelial cells.

ABSTRACT: Virus infections are a major cause of chronic obstructive pulmonary disease (COPD) exacerbations. Recently, Toll-like receptor 3 (TLR3) has been demonstrated to react to double-stranded RNA (dsRNA) and to be involved in the immune responses after viral infections. In the present study, we examined whether oxidative stress, which is involved in the pathogenesis of COPD, enhances the responses of TLR3 in airway epithelial cells. The effect of hydrogen peroxide (H(2)O(2)) on the release of IL-8 from BEAS-2B cells and primary human bronchial epithelial cells after stimulation with polyinosine-polycytidylic acid [poly(I:C)], a synthetic analog of viral dsRNA and a ligand for TLR3, and the signal transduction were examined. One hundred to 150 muM H(2)O(2) significantly potentiated the release of IL-8 from the epithelial cells after stimulation with 10 microg/ml poly(I:C). The H(2)O(2)-augmented IL-8 release was inhibited by treatment with N-acetylcysteine. One hundred micromoles of H(2)O(2) enhanced the translocation of nuclear factor (NF)-kappaB p65, but not that of interferon regulatory factor-3 (IRF-3), into the nucleus and the NF-kappaB DNA binding activity after poly(I:C) stimulation, which effect was inhibited not by the silencing of IRF-3 but by MG132, a proteasome inhibitor, or dexamethasone. One hundred micromoles of H(2)O(2) potentiated the TLR3 expression on the airway epithelial cells treated with poly(I:C). These data suggest that oxidative stress augments the response of TLR3 in airway epithelial cells via NF-kappaB and that this effect might be partly mediated by the enhancement of TLR3 expression. Modulation of this pathway may be a therapeutic target for viral-induced exacerbations of COPD.

SUBMITTER: Koarai A

PROVIDER: S-EPMC2891495 | biostudies-literature | 2010 Jun

REPOSITORIES: biostudies-literature

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Oxidative stress enhances toll-like receptor 3 response to double-stranded RNA in airway epithelial cells.

Koarai Akira A Sugiura Hisatoshi H Yanagisawa Satoru S Ichikawa Tomohiro T Minakata Yoshiaki Y Matsunaga Kazuto K Hirano Tsunahiko T Akamatsu Keiichiro K Ichinose Masakazu M

American journal of respiratory cell and molecular biology 20090713 6

Virus infections are a major cause of chronic obstructive pulmonary disease (COPD) exacerbations. Recently, Toll-like receptor 3 (TLR3) has been demonstrated to react to double-stranded RNA (dsRNA) and to be involved in the immune responses after viral infections. In the present study, we examined whether oxidative stress, which is involved in the pathogenesis of COPD, enhances the responses of TLR3 in airway epithelial cells. The effect of hydrogen peroxide (H(2)O(2)) on the release of IL-8 fro ...[more]

PMID: 19597128

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Project description:BACKGROUND:Interleukin-33 (IL-33) is a cytokine belonging to the IL-1 family, and its possible involvement in the pathophysiology of COPD and viral-induced exacerbations has been demonstrated. IL-33 has been shown to be increased in the airway epithelial cells from COPD patients, but the regulating mechanism of IL-33 expression in airway epithelial cells remains largely unknown. In the current study, we examined whether oxidative stress, which participates in the pathogenesis of COPD, affects the expression of IL-33 in airway epithelial cells and also evaluated the effect during viral infection. METHODS:The involvement of oxidative stress in the expression of IL-33, and its signal pathway was examined after stimulation with hydrogen peroxide (H2O2), with or without stimulation by polyinosinic-polycytidylic acid [poly (I:C)], a synthetic analogue of dsRNA that mimics viral infection, or rhinovirus infection in NCI-H292 cells and primary human bronchial epithelial cells (HBECs). In addition, the effect of antioxidant, N-acetylcysteine (NAC) in the expression of IL-33 was compared between HBECs from healthy subjects and those from COPD patients. RESULTS:Treatment with H2O2 significantly potentiated IL-33 expression in NCI-H292 cells, and the potentiation was reversed by NAC treatment. Mitogen-activated protein kinase (MAPK) inhibitors, but not nuclear factor-kappa B inhibitors, also significantly decreased the H2O2-potentiated IL-33 expression. In addition, H2O2 significantly potentiated the poly (I:C)- or rhinovirus-stimulated IL-33 expression. In HBECs from healthy subjects, H2O2-potentiated IL-33 expression and its reversal by NAC was also confirmed. Under the condition without H2O2-stimulation, treatment with NAC significantly decreased the expression of IL-33 in HBECs from COPD patients, but not in those from healthy subjects. CONCLUSIONS:These results demonstrate that oxidative stress involves in the expression of IL-33 in airway epithelial cells via MAPK signal pathway and it augments IL-33 expression during viral infection. This mechanism may participate in the regulation of IL-33 expression in airway epithelial cells in COPD and the viral-induced exacerbations. Modulation of this pathway could become a therapeutic target for viral-induced exacerbations of COPD.

Project description:Background25-hydroxycholesterol (25-HC) is one of the oxysterols, which are oxidized derivatives of cholesterol, and has been reported to be involved in the pathogenesis of atherosclerosis and Alzheimer's disease. In lung, the possible involvement of 25-HC in airway diseases has been revealed. In the present study, we examined whether 25-HC affects the release of cytokines and also modulates the responses of toll-like receptor 3 (TLR3) in airway epithelial cells.MethodsThe effect of 25-HC on the release of cytokines from primary human bronchial epithelial cells after stimulation with or without polyinosine-polycytidylic acid [poly(I:C)], a ligand for TLR3, and the signal transduction were examined.Results25-HC significantly potentiated the release of interleukin-8 (IL-8) and IL-6 from the cells. This effect was more potent compared with that of other oxysterols, 22-HC and 27-HC. GW3965 and TO901317, synthetic agonists of liver X receptors that are receptors for oxysterols, did not augment the IL-8 release. 25-HC enhanced the nuclear factor-kappa B (NF-κB) DNA binding activity and translocation of phosphorylated c-Jun into the nucleus. The release of IL-8 was inhibited by the NF-κB inhibitor, caffeic acid phenethyl ester (CAPE), an inhibitor of nuclear factor kappa-B alpha (IκBα) inhibitor, BAY 11-7085, and an inhibitor of nuclear factor kappa-B kinase-2 (IKK-2) inhibitor, SC-514, but not by a c-Jun N-terminal kinase (JNK) inhibitory peptide, L-JNKi1. 25-HC significantly potentiated IL-8 release in poly(I:C)-treated cells and the augmentation was inhibited by CAPE, BAY 11-7085, and SC-514. Furthermore, 25-HC potentiated the translocation of interferon regulatory factor 3 into the nucleus and the release of interferon-beta (IFN-β) in poly(I:C)-treated cells.ConclusionsThese data demonstrated that 25-HC augments the release of IL-8 and IL-6 via NF-κB signalling pathway and enhances the release of IL-8 and IFN-β after stimulation of TLR3 in airway epithelial cells. 25-HC may be involved in the neutrophilic airway inflammation through the stimulant effect of IL-8 and IL-6 release and also potentiate the TLR3-mediated innate immunity in airway diseases.

Project description:Background and aimsMitochondrial double-stranded RNA (mtdsRNA) and its innate immune responses have been reported previously; however, mtdsRNA generation and its effects on alcohol-associated liver disease (ALD) remain unclear. Here, we report that hepatic mtdsRNA stimulates toll-like receptor 3 (TLR3) in Kupffer cells through the exosome (Exo) to enhance interleukin (IL)-17A (IL-17A) production in ALD.Approach and resultsFollowing binge ethanol (EtOH) drinking, IL-17A production primarily increased in γδ T cells of wild-type (WT) mice, whereas the production of IL-17A was mainly facilitated by CD4+ T cells in acute-on-chronic EtOH consumption. These were not observed in TLR3 knockout (KO) or Kupffer cell-depleted WT mice. The expression of polynucleotide phosphorylase, an mtdsRNA-restricting enzyme, was significantly decreased in EtOH-exposed livers and hepatocytes of WT mice. Immunostaining revealed that mtdsRNA colocalized with the mitochondria in EtOH-treated hepatocytes from WT mice and healthy humans. Bioanalyzer analysis revealed that small-sized RNAs were enriched in EtOH-treated Exos (EtOH-Exos) rather than EtOH-treated microvesicles in hepatocytes of WT mice and humans. Quantitative real-time PCR and RNA sequencing analyses indicated that mRNA expression of mitochondrial genes encoded by heavy and light strands was robustly increased in EtOH-Exos from mice and humans. After direct treatment with EtOH-Exos, IL-1β expression was significantly increased in WT Kupffer cells but not in TLR3 KO Kupffer cells, augmenting IL-17A production of γδ T cells in mice and humans.ConclusionsEtOH-mediated generation of mtdsRNA contributes to TLR3 activation in Kupffer cells through exosomal delivery. Consequently, increased IL-1β expression in Kupffer cells triggers IL-17A production in γδ T cells at the early stage that may accelerate IL-17A expression in CD4+ T cells in the later stage of ALD. Therefore, mtdsRNA and TLR3 may function as therapeutic targets in ALD.

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Oxidative stress enhances toll-like receptor 3 response to double-stranded RNA in airway epithelial cells.

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Oxidative stress enhances toll-like receptor 3 response to double-stranded RNA in airway epithelial cells.

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