miR-181调控猪繁殖与呼吸综合症病毒复制
猪繁殖与呼吸综合症病毒（Porcine Reproductive and Respiratory Syndrome Virus, PRRSV）是养猪业最重要的病原体之一。大量的实验已证实宿主miRNA参与宿主与病原的相互作用。然而，宿主miRNA是否能调控PRRSV并用于抑制PRRSV的侵染未见有报道。中国农业大学封文海教授课题组正是针对此课题展开了系统研究*，研究成果发表在11月J Virol上。首先，研究者利用深度测序技术对PRRSV侵染组样本及其对照组样本进行miRNA表达谱发现分析（深度测序由联川生物承担完成），筛选出特异性表达的miR-181。miR-181是免疫反应的正调控因子，直接影响PRRSV感染。研究表明，miR-181 mimics通过特异性结合病毒基因组RNA开放阅读框4（Open Reading Frame 4, ORF4）的下游高度保守区域（高于96%），强烈抑制PRRSV体外复制。
研究发现，PRRSV复制的抑制作用具有特异性和剂量依赖性。在PRRSV感染Marc-145细胞中，在荧光素酶载体中病毒mRNA与miRNA-181靶序列共同竞争miRNA，结果导致荧光素酶活性受到较少抑制。进一步研究表明miRNA-181与PRRSV RNAs特异性互作。正如预期的，miR-181和其他潜在靶向PRRSV的miRNA（如miR-206）在低受纳细胞或组织的表达量比高受纳细胞或组织的更高。此外，与阴性对照组相比，高致病性PRRSV（HP-PRRSV）株感染的猪通过miR-181 mimics治疗，结果可大幅降低血液中病毒载量和解除PRRSV引起的发热。
本研究表明宿主miRNA可以调控PRRSV感染和病毒发病机理，也进一步证明了miRNA可以应用于RNAi介导的抗病毒治疗。
http://www.bioon.com/biology/Microbiology/536709.shtml
英文文章：
Additional expression of microRNA-181 inhibits Porcine Reproductive and Respiratory Syndrome Virus replication and its implications for controlling virus infection
[*]Xue-kun Guo1,2,
[*]Qiong Zhang1,2,
[*]Li Gao1,2,
[*]Ning Li1,3,
[*]Xin-xin Chen1,2 and
[*]Wen-hai Feng1,2,*
+ Author Affiliations
[*]1State Key Laboratories of Agrobiotechnology
[*]2Department of Microbiology and Immunology
[*]3Department of Molecular Biology, College of Biological Science, China Agricultural University, Beijing 100193, China
ABSTRACT Porcine reproductive and respiratory syndrome virus (PRRSV) is one of the most important viral pathogens in swine industry. Emerging evidence indicates that the host microRNAs (miRNAs) are involved in host-pathogen interactions. However, whether host miRNAs can target PRRSV and be used to inhibit PRRSV infection has not been reported. Recently, miR-181 has been identified as a positive regulator of immune response, and here we report that miR-181 can directly impair PRRSV infection. Our results showed that delivered miR-181 mimics can strongly inhibit PRRSV replication in vitro through specifically binding to a highly conserved region (over 96%) in the downstream of open reading frame 4 (ORF4) of the viral genomic RNA. The inhibition of PRRSV replication was specific and dose-dependent. In PRRSV-infected Marc-145 cells, the viral mRNAs could compete with miR-181-targeted sequence in luciferase vector to interact with miR-181 and result in less inhibition of luciferase activity, further demonstrating the specific interactions between miR-181 and PRRSV RNAs. As expected, miR-181 and other potential PRRSV-targeting miRNAs (such as miR-206) are expressed much more abundantly in low-permissive cells or tissues than in high-permissive cells or tissues. Importantly, highly pathogenic PRRSV (HP-PRRSV) strain-infected pigs treated with miR-181 mimics showed substantially decreased viral load in blood and relief from PRRSV-induced fever compared to negative control (NC)-treated controls. These results implicate the important role of host miRNAs in modulating PRRSV infection and viral pathogenesis, and also support the idea that host miRNAs could be useful for RNAi-mediated antiviral therapeutic strategies.
http://jvi.asm.org/content/early/2012/11/08/JVI.02386-12.full.pdf+html
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