Rivieccio Mark A, Suh Hyeon-Sook, Zhao Yongmei, Zhao Meng-Liang, Chin Keh Chuang, Lee Sunhee C, Brosnan Celia F
Department of Pathology, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461, USA.
J Immunol. 2006 Oct 1;177(7):4735-41. doi: 10.4049/jimmunol.177.7.4735.
TLR3 functions as a viral nucleic acid sentinel activated by dsRNA viruses and virus replication intermediates within intracellular vesicles. To explore the spectrum of genes induced in human astrocytes by TLR3, we used a microarray approach and the analog polyriboinosinic polyribocytidylic acid (pIC) as ligand. As expected for TLR activation, pIC induced a wide array of cytokines and chemokines known for their role in inflammatory responses, as well as up-regulation of the receptor itself. The data also showed activation of a broad spectrum of antiviral response genes. To determine whether pIC induced an antiviral state in astrocytes, a pseudotyped HIV viral particle, vesicular stomatitis virus g-env-HIV-1, was used. pIC significantly abrogated HIV-1 replication, whereas IL-1, which also potently activates astrocytes, did not. One of the most highly up-regulated genes on microarray was the protein viperin/cig5. We found that viperin/cig5 expression was dependent on IFN regulatory factor 3 and NF-kappaB signaling, and that repetitive stimulation with pIC, but not IL-1, further increased expression. Viperin induction could also be substantially inhibited by neutralizing Abs to IFN-beta, as could HIV-1 replication. To explore a role for viperin in IFN-beta-mediated inhibition of HIV-1, we used an RNA interference (RNAi) approach. RNAi directed against viperin, but not a scrambled RNAi, significantly inhibited viperin expression, and also significantly reversed pIC-induced inhibition of HIV-1 replication. We conclude that viperin contributes to the antiviral state induced by TLR3 ligation in astrocytes, supporting a role for astrocytes as part of the innate immune response against infection in the CNS.
Toll样受体3（TLR3）作为一种病毒核酸哨兵，可被双链RNA病毒和细胞内囊泡中的病毒复制中间体激活。为了探究TLR3在人星形胶质细胞中诱导的基因谱，我们使用了微阵列方法，并以类似物聚肌苷酸-聚胞苷酸（pIC）作为配体。正如TLR激活所预期的那样，pIC诱导了一系列以其在炎症反应中的作用而闻名的细胞因子和趋化因子，以及受体自身的上调。数据还显示了广泛的抗病毒反应基因的激活。为了确定pIC是否在星形胶质细胞中诱导抗病毒状态，使用了一种假型HIV病毒颗粒，即水疱性口炎病毒g包膜-HIV-1。pIC显著抑制了HIV-1复制，而同样能有效激活星形胶质细胞的白细胞介素-1则没有。微阵列上上调程度最高的基因之一是蛋白维甲酸诱导蛋白I/雪茄盒蛋白5（viperin/cig5）。我们发现viperin/cig5的表达依赖于干扰素调节因子3和核因子κB信号传导，并且用pIC重复刺激，而不是白细胞介素-1，会进一步增加其表达。维甲酸诱导蛋白I的诱导也可被抗干扰素-β的中和抗体显著抑制，HIV-1复制也是如此。为了探究维甲酸诱导蛋白I在干扰素-β介导的HIV-抑制中的作用，我们使用了RNA干扰（RNAi）方法。针对维甲酸诱导蛋白I的RNAi，而不是乱序RNAi，显著抑制了维甲酸诱导蛋白I的表达，并且也显著逆转了pIC诱导的HIV-1复制抑制。我们得出结论，维甲酸诱导蛋白I有助于TLR3连接在星形胶质细胞中诱导的抗病毒状态，支持星形胶质细胞作为中枢神经系统中针对感染的固有免疫反应一部分的作用。
