The RNA-activated Protein Kinase Enhances the Induction of Interferon-β and Apoptosis Mediated by Cytoplasmic RNA Sensors
The RNA-activated Protein Kinase Enhances the Induction of Interferon-β and Apoptosis Mediated by Cytoplasmic RNA Sensors
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DOI：
10.1074/jbc.m807888200
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发表时间：
2009-01-16
影响因子：
4.8
通讯作者：
Samuel, Charles E.
中科院分区：
文献类型：
--
作者：
McAllister, Christopher S.;Samuel, Charles E.
先天免疫系统检测到外源RNA可触发I型干扰素的诱导和细胞凋亡。在识别外源双链RNA(DsRNA)后，导致I型干扰素产生的重要抗病毒防御途径包括RIG-I家族解旋酶和IPS-1适配器胞浆途径，以及Toll样受体3和含有TIR结构域的适配器诱导的干扰素-β(TRIF)适配器膜相关途径，两者都激活干扰素调节因子3(IRF3)。除了触发先天免疫反应外，dsRNAs还被广泛用于通过RNA干扰途径在哺乳动物细胞中介导基因选择性沉默。我们研究了短干扰RNA，包括T7噬菌体聚合酶合成RNA(PRNA)，它像一些病毒RNA一样含有5‘-三磷酸，选择性地沉默基因表达并诱导干扰素-β和细胞凋亡。我们发现，PRNA介导的基因沉默和相关的非特异性促凋亡和干扰素诱导效应依赖于细胞系和RNA长度。长度为50个核苷酸的双链PRNAs和多聚肌苷多胞酸可激活RNA依赖的蛋白激酶(PKR)，并诱导显著水平的干扰素-β和细胞凋亡，而较短的PRNAs和化学合成的dsRNAs则不能。干扰素可促进RNA转染后效应型caspase的激活和细胞凋亡，去除5‘-磷酸可降低干扰素-β的诱导作用和细胞凋亡。除了IPS-1和IRF3外，最大限度地诱导I型干扰素-β和多聚肌胞苷多胞酸诱导细胞凋亡都需要PKR，而不是TRIF。
Detection of foreign RNA by the innate immune system can trigger the induction of type I interferon (IFN) and apoptosis. Important antiviral defense pathways that result in type I IFN production following the recognition of foreign doublestranded RNA (dsRNA) include the RIG-I family helicases and IPS-1 adaptor cytosolic pathway and the Toll-like receptor 3 and TIR domain-containing adaptor-inducing IFN-beta (TRIF) adaptor membrane-associated pathway, both of which activate IFN regulatory factor 3 (IRF3). In addition to triggering an innate immune response, dsRNAs are widely used to mediate geneselective silencing in mammalian cells by the RNA interference pathway. We investigated the ability of short interfering RNAs, including T7 phage polymerase-synthesized RNA (PRNA), which like some viral RNAs contains a 5'-triphosphate, to selectively silence gene expression and to cause induction of IFN-beta and apoptosis. We found that PRNA-mediated gene silencing and associated nonspecific pro-apoptotic and IFN-inducing effects were dependent on the cell line and RNA length. Double-stranded PRNAs 50 nucleotides long as well as polyinosinicpolycytidylic acid activated the RNA-dependent protein kinase (PKR) and induced significant levels of IFN-beta and apoptosis, whereas shorter PRNAs and chemically synthesized dsRNAs did not. Effector caspase activation and apoptosis following RNA transfection was enhanced by pretreatment with IFN, and removal of the 5'-phosphate from PRNAs decreased induction of both IFN-beta and apoptosis. PKR, in addition to IPS-1 and IRF3 but not TRIF, was required for maximal type I IFN-beta induction and the induction of apoptosis by both transfected PRNAs and polyinosinicpolycytidylic acid.