Host-directed combinatorial RNAi improves inhibition of diverse strains of influenza A virus in human respiratory epithelial cells

Influenza A virus infections are important causes of morbidity and mortality worldwide, and currently available prevention and treatment methods are suboptimal. In recent years, genome-wide investigations have revealed numerous host factors that are required for influenza to successfully complete its life cycle. However, only a select, small number of influenza strains were evaluated using this platform, and there was considerable variation in the genes identified across different investigations. In an effort to develop a universally efficacious therapeutic strategy with limited potential for the emergence of resistance, this study was performed to investigate the effect of combinatorial RNA interference (RNAi) on inhibiting the replication of diverse influenza A virus subtypes and strains. Candidate genes were selected for targeting based on the results of multiple previous independent genome-wide studies. The effect of single and combinatorial RNAi on the replication of 12 diverse influenza A viruses, including three strains isolated from birds and one strain isolated from seals, was then evaluated in primary normal human bronchial epithelial cells. After excluding overly toxic siRNA, two siRNA combinations were identified that reduced mean viral replication by greater than 79 percent in all mammalian strains, and greater than 68 percent in all avian strains. Host-directed combinatorial RNAi effectively prevents growth of a broad range of influenza virus strains in vitro, and is a potential therapeutic candidate for further development and future in vivo studies.

甲型流感病毒感染是全球范围内发病率与死亡率的重要诱因，当前临床可用的预防与治疗手段仍不甚理想。近年来，全基因组研究已揭示了诸多甲型流感病毒完成自身生命周期所必需的宿主因子。然而，既往此类研究仅评估了少量甲型流感病毒毒株，且不同研究间所鉴定得到的基因存在显著差异。为开发一款耐药风险有限的广谱高效治疗策略，本研究旨在探究组合RNA干扰（RNAi）对不同甲型流感病毒亚型及毒株复制的抑制效果。本研究基于多项既往独立全基因组研究的结果，筛选出待靶向的候选基因。随后，本研究在原代正常人类支气管上皮细胞中，评估了单剂及组合RNA干扰对12株不同甲型流感病毒复制的影响，其中包括3株禽类分离毒株与1株海豹分离毒株。在排除毒性过强的小干扰RNA（siRNA）后，研究团队筛选得到两组siRNA联合方案，可使所有哺乳动物毒株的平均病毒复制水平降低79%以上，所有禽类毒株的平均病毒复制水平降低68%以上。靶向宿主的组合RNA干扰可在体外有效抑制多种甲型流感病毒毒株的增殖，具备作为潜在治疗候选方案开展后续开发及未来体内研究的价值。