An RNA-targeted platform for anti-flavivirus drug discovery

摘要 新出现和再次出现的蚊媒黄病毒导致广泛的死亡率、发病率和经济负担。预防和治疗蚊媒黄病毒的选择有限：黄病毒疫苗面临独特的发展挑战，没有抗病毒疗法可用，蚊媒已被证明难以根除。尽管有针对黄热病和日本脑炎病毒的疫苗，但这两种黄病毒每年总共导致75,000多人死亡。世界上一半的人口面临感染登革热病毒(DENV)的风险，包括寨卡病毒在内的新出现的黄病毒构成了重大的公共卫生挑战。 RNA是小分子药物发现的一个引人注目的靶点，而RNA病毒的基因组，如黄病毒，包含高度保守的靶向结构。多种天然产物以核糖体RNA为靶点，为RNA作为药物靶点建立了概念证据；然而，以RNA为靶点的药物发现仍然是一个新领域。DENV RNA基因组中特定的三级结构最近被证明是病毒复制所必需的。这些结构在蚊媒黄病毒中高度保守，干扰它们的形成会抑制包装和复制，这表明破坏这些RNA基序的小分子将具有广谱抗黄病毒活性。 在Ribometrix，我们的铅发现平台将非常快速和高通量的初始筛选与基于SHAPE技术的二次分析相结合，SHAPE技术是RNA结构分析的黄金标准。我们计划应用我们的平台来识别具有良好药物化学性质的小分子，这些小分子结合并破坏必要的DENV RNA基序的结构。这些先导化合物将作为第二阶段项目中开发抗DENV和广谱抗黄病毒疗法的基础。 RNA具有广泛相似的整体特性，因此，允许在单个病例中有效靶向RNA的策略可能会允许靶向不同的治疗重要RNA。Ribmetrix的长期愿景是应用这一平台技术来发现针对功能性RNA结构的小分子疗法，这些结构涉及到尚无批准疗法的适应症。通过这项研究，我们将建立一种高效和通用的RNA靶向配体发现方法的原则证明。

SUMMARY Emerging and re-emerging mosquito-borne flaviviruses cause widespread mortality, morbidity, and economic burden. Options for prevention and treatment of mosquito-borne flaviviruses are limited: Flavivirus vaccines face unique development challenges, no antiviral therapies are available, and the mosquito vectors have proven difficult to eradicate. Despite vaccines against Yellow Fever and Japanese encephalitis viruses, these two flaviviruses together cause more than 75,000 deaths each year. Half of the world’s population is at risk of Dengue virus (DENV) infection, and emerging flaviviruses, including the Zika virus, pose significant public health challenges. RNA is a compelling target for small-molecule drug discovery, and the genomes of RNA viruses, such as flaviviruses, contain highly conserved targetable structures. Multiple natural products target ribosomal RNA, establishing proof of concept for RNA as a drug target; however, RNA-targeted drug discovery remains a nascent field. Specific tertiary structures in the DENV RNA genome have recently been shown to be essential for viral replication. These structures are highly conserved across mosquito-borne flaviviruses and interfering with their formation inhibits packaging and replication, suggesting that small molecules that disrupt these RNA motifs will have broad-spectrum antiflaviviral activity. At Ribometrix, our lead discovery platform combines a very rapid and high-throughput initial screen with a secondary assay based on SHAPE technology, the gold standard for RNA structure analyses. We plan to apply our platform to identify small molecules with favorable medicinal chemistry properties that bind to and disrupt the structure of essential DENV RNA motifs. These lead compounds will serve as the foundation for the development of anti-DENV and broad-spectrum antiflaviviral therapies in a Phase 2 project. RNAs share broadly similar overall properties, so a strategy that allows RNA to be targeted efficiently in a single case will likely allow targeting of diverse therapeutically important RNAs. The long-term vision of Ribometrix is to apply this platform technology to discover small-molecule therapeutics that target functional RNA structures involved in indications for which there are no approved therapies. With this study, we will establish proof-of-principle for an efficient and generic approach for RNA-targeted ligand discovery.