BROAD-SPECTRUM RNAi THERAPEUTICS FOR FLAVIVIRAL ENCEPHALITIS

描述（由申请人提供）： 西尼罗河病毒（WN）和日本脑炎病毒（JE）是黄病毒，可引起毁灭性的急性神经系统疾病，目前还没有有效的治疗这些病毒感染。我们已经开发了一种基于RNA干扰的治疗方法来抑制这些病毒，并显示了使用单一siRNA作为广谱抗病毒剂来抑制小鼠中由WNV和JEV引起的致命感染的可行性。然而，利用siRNA用于人类治疗的潜力的主要挑战是缺乏合适的递送方法。由于血脑屏障的存在，在CNS中的递送特别困难。初步研究表明，一种来源于狂犬病病毒糖蛋白（RVG）的小肽可能允许神经元细胞特异性靶向。值得注意的是，当与带正电荷的多聚精氨酸肽融合时，嵌合RVG-9 R肽能够结合siRNA（通过电荷相互作用）并在小鼠静脉内注射后将siRNA递送至脑细胞，导致脑中的特异性基因沉默。因此，我们已经确定了一种潜在的“siRNA药物”来治疗黄病毒性脑炎，并开发了一种临床上可行的方法，通过简单的静脉注射将其递送到大脑。 在本提案中，我们将与Alnylam Pharmaceuticals Inc.合作，对有效性和安全性进行临床前评价，并将产品开发推向人类治疗。具体来说，在aim 1中，我们将进行全面筛选，以选择最有效的2-3个前导抗病毒siRNA，并对其进行化学修饰，以获得适当的药物样特性。在目标2中，我们将解决生物利用度和安全性/毒理学问题，并确定RNAi效应的特异性。在目标3中，我们将测试在感染前和感染后不同时间静脉内治疗抑制JEV和WNV诱导的脑炎的功效。为了提高这种治疗方法的治疗指数和安全性，在目的4中，我们将使用RVG作为神经元靶向剂开发几种不同的siRNA/肽复合物制剂。 相关性： 这些研究预计将导致开发一种可行的基于RNAi的病毒性脑炎治疗策略。此外，我们还开发了一种用于CNS递送siRNA和潜在的其他治疗剂的经血管方法，这将有助于治疗各种神经系统疾病。

DESCRIPTION (provided by applicant): West Nile (WN) and Japanese encephalitis (JE) viruses are flaviviruses that can cause a devastating acute neurological illness and currently there is no effective treatment for these viral infections. We have developed a RNA interference-based therapeutic method to suppress these viruses and shown the feasibility of using a single siRNA as a broad-spectrum antiviral agent to suppress fatal infections caused by both WNV and JEV in mice. However, the major challenge for harnessing the potential of siRNA for human therapy is the lack of suitable delivery methods. Delivery is particularly difficult in the CNS because of the presence of the blood-brain barrier. Preliminary studies suggest that a small peptide derived from the Rabies virus glycoprotein (RVG) may allow neuronal cell-specific targeting. Remarkably, when fused to a positively charged polymeric arginine peptide, the chimeric RVG-9R peptide was able to bind siRNA (by charge interaction) and deliver the siRNA to brain cells after intravenous injection in mice, resulting in specific gene silencing in the brain. Thus, we have identified a potential "siRNA drug" to treat flaviviral encephalitis as well as developed a clinically feasible method of delivering it to the brain by simple intravenous injection. In this proposal, in association with Alnylam Pharmaceuticals Inc, we will conduct preclinical evaluation of efficacy and safety, and advance the product development towards human therapy. Specifically, in aim1, we will conduct a comprehensive screen to select the most potent 2-3 lead antiviral siRNAs and chemically modify them for proper drug-like properties. In aim 2 we will address the bioavailability and safety/toxicology issues and determine the specificity of RNAi effects. In aim 3, we will test the efficacy of intravenous treatment to suppress encephalitis induced by JEV and WNV, both before and at different times after infection. To enhance the therapeutic index and safety of this treatment approach, in Aim 4 we will develop several different formulations of siRNA/peptide complex using RVG as the neuronal targeting agent. Relevance: These studies are expected to lead to the development of a viable RNAi-based treatment strategy for viral encephalitis. In addition, we would have developed a transvascular method for CNS delivery of siRNA and potentially other therapeutic agents that would facilitate treatment of a variety of neurological diseases.