NLRP4 negatively regulates type I interferon signaling by targeting the kinase TBK1 for degradation via the ubiquitin ligase DTX4

The Center for Cell and Gene Therapy, Baylor College of Medicine, Houston, Texas, USA.
Nature Immunology (Impact Factor: 20). 03/2012; 13(4):387-95. DOI: 10.1038/ni.2239
Source: PubMed


Stringent control of the type I interferon signaling pathway is important for maintaining host immune responses and homeostasis, yet the molecular mechanisms responsible for its tight regulation are still poorly understood. Here we report that the pattern-recognition receptor NLRP4 regulated the activation of type I interferon mediated by double-stranded RNA or DNA by targeting the kinase TBK1 for degradation. NLRP4 recruited the E3 ubiquitin ligase DTX4 to TBK1 for Lys48 (K48)-linked polyubiquitination at Lys670, which led to degradation of TBK1. Knockdown of either DTX4 or NLRP4 abrogated K48-linked ubiquitination and degradation of TBK1 and enhanced the phosphorylation of TBK1 and the transcription factor IRF3. Our results identify a previously unrecognized role for NLRP4 in the regulation of type I interferon signaling and provide molecular insight into the mechanisms by which NLRP4-DTX4 targets TBK1 for degradation.

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    • "On the other hand, the expression of DTX4 was up-regulated in CIKIL-15 which positively regulated the production of type I interferon through NLRP4 [50]. Moreover, the expression of IL-21R whose ligand is involved in natural killer cell was also increased in CIKIL-15. "
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    ABSTRACT: Background Cytokine-induced killer (CIK) cells are an emerging approach of cancer treatment. Our previous study have shown that CIK cells stimulated with combination of IL-2 and IL-15 displayed improved proliferation capacity and tumor cytotoxicity. However, the mechanisms of CIK cell proliferation and acquisition of cytolytic function against tumor induced by IL-2 and IL-15 have not been well elucidated yet. Methods CIKIL-2 and CIKIL-15 were generated from peripheral blood mononuclear cells primed with IFN-γ, and stimulated with IL-2 and IL-15 in combination with OKT3 respectively. RNA-seq was performed to identify differentially expressed genes, and gene ontology and pathways based analysis were used to identify the distinct roles of IL-2 and IL-15 in CIK preparation. Results The results indicated that CIKIL-15 showed improved cell proliferation capacity compared to CIKIL-2. However, CIKIL-2 has exhibited greater tumor cytotoxic effect than CIKIL-15. Employing deep sequencing, we sequenced mRNA transcripts in CIKIL-2 and CIKIL-15. A total of 374 differentially expressed genes (DEGs) were identified including 175 up-regulated genes in CIKIL-15 and 199 up-regulated genes in CIKIL-2. Among DEGs in CIKIL-15, Wnt signaling and cell adhesion were significant GO terms and pathways which related with their functions. In CIKIL-2, type I interferon signaling and cytokine-cytokine receptor interaction were significant GO terms and pathways. We found that the up-regulation of Wnt 4 and PDGFD may contribute to enhanced cell proliferation capacity of CIKIL-15, while inhibitory signal from interaction between CTLA4 and CD80 may be responsible for the weak proliferation capacity of CIKIL-2. Moreover, up-regulated expressions of CD40LG and IRF7 may make for improved tumor cytolytic function of CIKIL-2 through type I interferon signaling. Conclusions Through our findings, we have preliminarily elucidated the cells proliferation and acquisition of tumor cytotoxicity mechanism of CIKIL-15 and CIKIL-2. Better understanding of these mechanisms will help to generate novel CIK cells with greater proliferation potential and improved tumor cytolytic function.
    Full-text · Article · Aug 2014 · BMC Medical Genomics
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    • "The RT-PCR exponential phase was determined at 26 and 32 cycles, for GAPDH and IFN-β expression, respectively, to allow semiquantitative comparison of cDNAs produced from identical reactions. The primers and PCR conditions are as previously described (Cui et al., 2012;Ferronato et al., 2013). The IFN-β expression analyses were performed in triplicate and repeated in at least three independent experiments. "

    Full-text · Article · Jan 2014 · Retrovirology
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    • "Nevertheless, NLRP4 expression in humans is found in various organs including the lung (142–144). In vitro, this NLR has the feature of a negative regulator of inflammatory responses by lowering NF-κB activation and IFNβ production (143, 144). Another particularity of NLRP4 is that its PYD is structurally different compared to the one in other NLRs, leading to the absence of interaction of NLRP4 with ASC (145). "
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    ABSTRACT: The lung is a particularly vulnerable organ at the interface of the body and the exterior environment. It is constantly exposed to microbes and particles by inhalation. The innate immune system needs to react promptly and adequately to potential dangers posed by these microbes and particles, while at the same time avoiding extensive tissue damage. Nucleotide-binding oligomerization domain-like receptors (NLRs) represent a group of key sensors for microbes and damage in the lung. As such they are important players in various infectious as well as acute and chronic sterile inflammatory diseases, such as pneumonia, chronic obstructive pulmonary disease (COPD), acute lung injury/acute respiratory distress syndrome, pneumoconiosis, and asthma. Activation of most known NLRs leads to the production and release of pro-inflammatory cytokines, and/or to the induction of cell death. We will review NLR functions in the lung during infection and sterile inflammation.
    Full-text · Article · Nov 2013 · Frontiers in Immunology
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