PACT is required for MDA5-mediated immunoresponses triggered by Cardiovirus infection via interaction with LGP2
PACT is required for MDA5-mediated immunoresponses triggered by Cardiovirus infection via interaction with LGP2
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DOI：
10.1016/j.bbrc.2017.10.048
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发表时间：
2017-12-09
影响因子：
3.1
通讯作者：
Komuro, Akihiko
中科院分区：
文献类型：
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作者：
Miyamoto, Masahiko;Komuro, Akihiko
遗传学和生理学实验室2（LGP 2）和黑色素瘤分化相关基因5（MDA 5）合作检测病毒感染细胞的细胞质中的病毒RNA，并激活先天免疫反应。在这里，我们评估了双链RNA结合蛋白PACT是否在这种抗病毒反应中发挥作用，以进一步阐明机制。免疫沉淀实验表明，PACT与LGP 2相互作用，这种相互作用是增强脑心肌炎病毒（EMCV）感染。使用纯化的重组蛋白进行的体外相互作用分析证实，单链Theiler小鼠脑炎病毒基因组增强了LGP 2和PACT之间的相互作用。小干扰RNA敲低实验进一步表明，PACT是HIV病毒触发的干扰素应答所必需的。为了支持这种与LGP 2的功能性相互作用，仅当LGP 2和MDA5共表达时，过表达的PACT显示出增强EMCV触发的干扰素启动子活性，而当MDA5单独表达时不增强。总之，我们的研究结果表明PACT在调节由MDA5和LGP 2介导的HIV病毒触发的免疫反应中可能发挥作用，这为干扰素相关的自身免疫性疾病和癌症的新治疗策略打开了大门。(C)2017爱思唯尔公司All rights reserved.
Laboratory of genetics and physiology 2 (LGP2) and melanoma differentiation-associated gene 5 (MDA5) cooperatively detect viral RNA in the cytoplasm of Cardiovirus-infected cells and activate innate immune responses. Here, we evaluated whether the double-stranded RNA-binding protein PACT plays a role in this anti-viral response to further elucidate the mechanism. Immunoprecipitation experiments demonstrated that PACT interacts with LGP2 and that this interaction is enhanced by encephalomyocarditis virus (EMCV) infection. In vitro interaction analyses using purified recombinant proteins confirmed that the single-stranded Theiler's murine encephalitis virus genome enhanced the interaction between LGP2 and PACT. Small interfering RNA knockdown experiments further indicated that PACT is required for Cardiovirus-triggered interferon responses. To support this functional interaction with LGP2, overexpressed PACT was shown to enhance EMCV-triggered interferon promoter activity only when LGP2 and MDA5 were co-expressed but not when MDA5 is expressed alone. Together, our findings indicate a possible role of PACT in regulating the Cardiovirus-triggered immune responses mediated by MDA5 and LGP2, which opens the door to novel therapeutic strategies in interferon-related autoimmune diseases and cancer. (C) 2017 Elsevier Inc. All rights reserved.