Faculty of Veterinary Science, Building B14, The University of Sydney, Sydney, NSW 2006, Australia.
Vet Microbiol. 2011 Jun 2;150(3-4):220-9. doi: 10.1016/j.vetmic.2011.01.023. Epub 2011 Feb 1.
Infection with virulent biotypes of feline coronavirus (FCoV) can result in the development of feline infectious peritonitis (FIP), a typically fatal immune mediated disease for which there is currently no effective antiviral treatment. In this study we demonstrate the ability of small interfering RNA (siRNA) mediated RNA interference (RNAi) to inhibit the replication of virulent FCoV strain FIPV WSU 79-1146 in an immortalised feline cell line. A panel of eight synthetic siRNAs targeting four different regions of the FCoV genome were tested for antiviral effects. Efficacy was determined by qRT-PCR of intracellular viral genomic and messenger RNA, TCID50 infectivity assay of extracellular virus, and direct IFA for viral protein expression. All siRNAs demonstrated an inhibitory effect on viral replication in vitro. The two most effective siRNAs, targeting the untranslated 5' leader sequence (L2) and the nucleocapsid gene (N1), resulted in a >95% reduction in extracellular viral titre. Further characterisation of these two siRNAs demonstrated their efficacy when used at low concentrations and in cells challenged with high viral loads. Taken together these findings provide important information for the potential therapeutic application of RNAi in treating FIP.
感染强毒型猫冠状病毒（FCoV）可导致猫传染性腹膜炎（FIP）的发生，这是一种典型的致命性免疫介导疾病，目前尚无有效的抗病毒治疗方法。在本研究中，我们证明了小干扰 RNA（siRNA）介导的 RNA 干扰（RNAi）能够抑制强毒 FCoV 株 FIPV WSU 79-1146 在永生化猫细胞系中的复制。针对 FCoV 基因组的四个不同区域设计了 8 个合成 siRNA 进行抗病毒作用的测试。通过细胞内病毒基因组和信使 RNA 的 qRT-PCR、细胞外病毒的 TCID50 感染性测定和病毒蛋白表达的直接 IFA 来确定功效。所有 siRNA 均在体外显示出抑制病毒复制的作用。针对非翻译 5' 引导序列（L2）和核衣壳基因（N1）的两种最有效的 siRNA 导致细胞外病毒滴度降低超过 95%。对这两种 siRNA 的进一步表征表明，当在低浓度和高病毒载量下挑战细胞时，它们具有功效。这些发现为 RNAi 在治疗 FIP 中的潜在治疗应用提供了重要信息。
