Dataset Information

IκBζ augments IL-12- and IL-18-mediated IFN-γ production in human NK cells.

ABSTRACT: Interferon-γ (IFN-γ) production by natural killer (NK) cells and cytotoxic lymphocytes is a key component of innate and adaptive immune responses. Because inhibitor of κB-ζ (IκBζ), a Toll-like receptor (TLR)/interleukin-1 receptor (IL-1R) inducible transcription factor, regulates IFN-γ production in KG-1 cells, we tested IκBζ's role in the classic lymphocyte pathway of IL-12/IL-18-induced IFN-γ. Upon stimulation with IL-12/IL-18, monocyte-depleted human peripheral blood lymphocytes expressed the 79-kDa form of IκBζ and released IFN-γ. CD56(+) NK cells were shown to be the IκBζ-producing lymphocyte subpopulation, which also released abundant IFN-γ in response to IL-12/IL-18. Importantly, IκBζ was undetectable in CD56(-) lymphocytes where IFN-γ release was 10-fold lower. In addition, small interfering RNA knockdown of IκBζ suppressed IFN-γ expression in CD56(+) cells. The association of IκBζ with the IFN-γ promoter was documented by chromatin immunoprecipitation. IFN-γ promoter activity from IκBζ overexpression was confirmed by luciferase reporter assay. Finally, IκBζ coprecipitated with p65 and p50 NF-κB in NK cells in response to IL-12/IL-18, suggesting that IκBζ's effects on IFN-γ promoter activity are coregulated by NF-κB. These results suggest that IκBζ functions as an important regulator of IFN-γ in human NK cells, further expanding the class of IκBζ-modulated genes.

SUBMITTER: Kannan Y

PROVIDER: S-EPMC3062297 | biostudies-literature | 2011 Mar

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

IκBζ augments IL-12- and IL-18-mediated IFN-γ production in human NK cells.

Kannan Yashaswini Y Yu Jianhua J Raices Raquel M RM Seshadri Sudarshan S Wei Min M Caligiuri Michael A MA Wewers Mark D MD

Blood 20110111 10

Interferon-γ (IFN-γ) production by natural killer (NK) cells and cytotoxic lymphocytes is a key component of innate and adaptive immune responses. Because inhibitor of κB-ζ (IκBζ), a Toll-like receptor (TLR)/interleukin-1 receptor (IL-1R) inducible transcription factor, regulates IFN-γ production in KG-1 cells, we tested IκBζ's role in the classic lymphocyte pathway of IL-12/IL-18-induced IFN-γ. Upon stimulation with IL-12/IL-18, monocyte-depleted human peripheral blood lymphocytes expressed the ...[more]

PMID: 21224476

Similar Datasets

Project description:Mitochondrial activation and the production of mitochondrial reactive oxygen species (mROS) are crucial for CD4+ T cell responses and have a role in naïve cell signaling after TCR activation. However, little is known about mROS role in TCR-independent signaling and in recall responses. Here, we found that mROS are required for IL-12 plus IL-18-driven production of IFN-γ, an essential cytokine for inflammatory and autoimmune disease development. Compared to TCR stimulation, which induced similar levels of mROS in naïve and memory-like cells, IL-12/IL-18 showed faster and augmented mROS production in memory-like cells. mROS inhibition significantly downregulated IFN-γ and CD44 expression, suggesting a direct mROS effect on memory-like T cell function. The mechanism that promotes IFN-γ production after IL-12/IL-18 challenge depended on the effect of mROS on optimal activation of downstream signaling pathways, leading to STAT4 and NF-κB activation. To relate our findings to IFN-γ-driven lupus-like disease, we used Fas-deficient memory-like CD4+ T cells from lpr mice. Importantly, we found significantly increased IFN-γ and mROS production in lpr compared with parental cells. Treatment of WT cells with FasL significantly reduced mROS production and the activation of signaling events leading to IFN-γ. Moreover, Fas deficiency was associated with increased mitochondrial levels of cytochrome C and caspase-3 compared with WT memory-like cells. mROS inhibition significantly reduced the population of disease-associated lpr CD44hiCD62LloCD4+ T cells and their IFN-γ production. Overall, these findings uncovered a previously unidentified role of Fas/FasL interaction in regulating mROS production by memory-like T cells. This apoptosis-independent Fas activity might contribute to the accumulation of CD44hiCD62LloCD4+ T cells that produce increased IFN-γ levels in lpr mice. Overall, our findings pinpoint mROS as central regulators of TCR-independent signaling, and support mROS pharmacological targeting to control aberrant immune responses in autoimmune-like disease.

Project description:IntroductionToll-like receptor (TLR)4 promotes joint inflammation in mice. Despite that several studies report a functional link between TLR4 and interleukin-(IL-)1? in arthritis, TLR4-mediated regulation of the complicated cytokine network in arthritis is poorly understood. To address this, we investigated the mechanisms by which TLR4 regulates the cytokine network in antibody-induced arthritis.MethodsTo induce arthritis, we injected mice with K/BxN serum. TLR4-mediated pathogenesis in antibody-induced arthritis was explored by measuring joint inflammation, cytokine levels and histological alteration.ResultsCompared to wild type (WT) mice, TLR4-/- mice showed attenuated arthritis and low interferon (IFN)-?, IL-12p35 and IL-1? transcript levels in the joints, but high transforming growth factor (TGF)-? expression. Injection of lipopolysaccharide (LPS) enhanced arthritis and exaggerated joint cytokine alterations in WT, but not TLR4-/- or IL-12p35-/- mice. Moreover, STAT4 phosphorylation in joint cells and intracellular IL-12p35 expression in macrophages, mast cells and Gr-1+ cells were detected in WT mice with arthritis and enhanced by LPS injection. Therefore, IL-12p35 appears to act downstream of TLR4 in antibody-induced arthritis. TLR4-mediated IL-12 production enhanced IFN-? and IL-1? production via T-bet and pro-IL-1? production. Recombinant IL-12, IFN-? and IL-1? administration restored arthritis, but reduced joint TGF-? levels in TLR4-/- mice. Moreover, a TGF-? blockade restored arthritis in TLR4-/- mice. Adoptive transfer of TLR4-deficient macrophages and mast cells minimally altered joint inflammation and cytokine levels in macrophage- and mast cell-depleted WT mice, respectively, whereas transfer of WT macrophages or mast cells restored joint inflammation and cytokine expression. Gr-1+ cell-depleted splenocytes partially restored arthritis in TLR4-/- mice.ConclusionTLR4-mediated IL-12 production by joint macrophages, mast cells and Gr-1+ cells enhances IFN-? and IL-1? production, which suppresses TGF-? production, thereby promoting antibody-induced arthritis.

Dataset Information

IκBζ augments IL-12- and IL-18-mediated IFN-γ production in human NK cells.

Publications

IκBζ augments IL-12- and IL-18-mediated IFN-γ production in human NK cells.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets