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Transcriptional suppression of IL-27 production by Mycobacterium tuberculosis-activated p38 MAPK via inhibition of AP-1 binding.

ABSTRACT: Mycobacterium tuberculosis remains a major global challenge to human health care, and the mechanisms of how M. tuberculosis evades host immune surveillance to favor its survival are still largely unknown. In this study, we found that bacillus Calmette-Guérin (BCG) and viable M. tuberculosis as well as M. tuberculosis lysates could activate IL-27 expression in human and mouse macrophages by induction of p28 subunit transcription. However, in parallel with these effects, BCG and M. tuberculosis lysate stimulation of macrophages induced activation of p38 MAPK signaling molecules MLK3/MKK3/MK2 to prevent maximal IL-27 production. M. tuberculosis lysate-induced p28 transcription was dependent on MyD88 signaling pathway. AP-1/c-Fos was shown to bind directly to the p28 promoter and induce p28 expression after M. tuberculosis lysate stimulation. Overexpression of p38? inhibited the binding of c-Fos to the p28 promoter but had no effect on c-Fos protein expression or phosphorylation in response to M. tuberculosis lysate stimulation. Furthermore, blockade of p38 by SB203580 enhanced M. tuberculosis-induced AP-1 binding to the p28 promoter. Importantly, we show that adding exogenous IL-27 to increase the levels produced by PBMCs stimulated with live mycobacteria enhanced the ability of BCG-expanded T cells to inhibit intracellular mycobacterial growth in human macrophages. Taken together, our data demonstrate that mycobacterial stimulation induces both IL-27 production and p38 MAPK activation. Strategies designed to tip the balance toward positive regulation of p28 induction by mycobacteria could lead to enhanced protective tuberculosis immunity.

SUBMITTER: Zhang J

PROVIDER: S-EPMC3150584 | biostudies-literature | 2011 May

REPOSITORIES: biostudies-literature

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Transcriptional suppression of IL-27 production by Mycobacterium tuberculosis-activated p38 MAPK via inhibition of AP-1 binding.

Zhang Jidong J Qian Xuesong X Ning Huan H Eickhoff Christopher S CS Hoft Daniel F DF Liu Jianguo J

Journal of immunology (Baltimore, Md. : 1950) 20110411 10

Mycobacterium tuberculosis remains a major global challenge to human health care, and the mechanisms of how M. tuberculosis evades host immune surveillance to favor its survival are still largely unknown. In this study, we found that bacillus Calmette-Guérin (BCG) and viable M. tuberculosis as well as M. tuberculosis lysates could activate IL-27 expression in human and mouse macrophages by induction of p28 subunit transcription. However, in parallel with these effects, BCG and M. tuberculosis ly ...[more]

PMID: 21482740

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Project description:Activation of cellular kinases and transcription factors mediates the early phase of the cellular response to chemically or biologically induced stress. In the present study we investigated the oxidant/antioxidant balance in Huh-7 cells expressing the HCV (hepatitis C virus) subgenomic replicon, and observed a 5-fold increase in oxidative stress during HCV replication. We used MnSOD (manganese-superoxide dismutase) as an indicator of the cellular antioxidant response, and found that its activity, protein levels and promoter activity were significantly increased, whereas Cu/ZnSOD was not affected. The oxidative stress-induced protein kinases p38 MAPK (mitogen-activated protein kinase) and JNK (c-Jun N-terminal kinase) were activated in the HCV repliconcontaining cells and in Huh-7 cells transduced with Ad-NS5A [a recombinant adenovirus encoding NS5A (non-structural protein 5A)], coupled with a 4-5-fold increase in AP-1 (activator protein-1) DNA binding. Ava.1 cells, which encode a replication-defective HCV replicon, showed no significant changes in MnSOD, p38 MAPK or JNK activity. The AP-1 inhibitors dithiothreitol and N -acetylcysteine, as well as a dominant negative AP-1 mutant, significantly reduced AP-1 activation, demonstrating that this activation is oxidative stress-related. Exogenous NS5A had no effect on AP-1 activation in vitro, suggesting that NS5A acts at the upstream targets of AP-1 involving p38 MAPK and JNK signalling cascades. AP-1-dependent gene expression was increased in HCV subgenomic replicon-expressing Huh-7 cells. MnSOD activation was blocked by inhibitors of JNK (JNKI1) and p38 MAPK (SB203580), but not by an ERK (extracellular-signal-regulated kinase) inhibitor (U0126), in HCV-replicating and Ad-NS5A-transduced cells. Our results demonstrate that cellular responses to oxidative stress in HCV subgenomic replicon-expressing and Ad-NS5A-transduced cells are regulated by two distinct signalling pathways involving p38 MAPK and JNK via AP-1 that is linked to increased oxidative stress and therefore to an increased antioxidant MnSOD response.

Dataset Information

Transcriptional suppression of IL-27 production by Mycobacterium tuberculosis-activated p38 MAPK via inhibition of AP-1 binding.

Publications

Transcriptional suppression of IL-27 production by Mycobacterium tuberculosis-activated p38 MAPK via inhibition of AP-1 binding.

Similar Datasets

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