RNA Interference of Influenza Virus Infection

描述（由申请方提供）：甲型流感病毒是人类最广泛的感染之一。在一个典型的年份里，它感染了美国10-20%的人口，造成多达4万人死亡在1918年流感病毒大流行期间，全世界有2000多万人死亡。即使到现在，另一场大流行的威胁仍在继续，因为尽管作出了密集的努力，但仍然没有有效的治疗流感感染的方法，预防工作也是随意的。现有的疫苗价值有限，因为它们针对的流感病毒是根据最近流行的毒株通过“最佳猜测”确定的。甲型流感病毒的毒力来自于i）其容易通过气溶胶传播，ii）其逃避保护性免疫的能力，以及iii）病毒的新的毒性毒株的周期性出现。出于这些原因，美国国立卫生研究院已将流感感染指定为生物防御的首要领域。RNA干扰（RNAi）是双链RNA指导动物和植物细胞中信使RNA的序列特异性降解的过程。研究表明，RNAi可以由合成的21个核苷酸的小干扰RNA（siRNA）分子双链体触发。本项目旨在研究siRNA在预防和治疗流感病毒感染方面的作用。具体地，我们提出i）鉴定在培养的细胞中有效抑制流感病毒产生的siRNA，ii）开发用于将siRNA有效递送到流感感染通常发生的上呼吸道和肺的细胞中的系统，iii）研究siRNA抑制小鼠中流感感染的体内功效，以及iv）阐明siRNA抑制流感病毒产生的机制。从拟议的研究中获得的结果可能为进一步开发siRNA作为预防和治疗人类流感病毒感染提供基础。从理论上讲，即使出现新的病毒株，基于siRNA的治疗也应该保持有效。

DESCRIPTION (provided by applicant): Influenza A virus causes one of the most widespread infections in humans. In a typical year, it infects 10-20% of the population in the U.S., causing up to 40,000 deaths. During the 1918 influenza virus pandemic, over 20 million people died worldwide. The threat of another pandemic continues even now because, despite intensive efforts, there is still no effective therapy for influenza infection and prevention is haphazard. Existing vaccines are of limited value because the influenza viruses they target are determined by "best guess," based upon recently prevalent strains. The virulence of influenza A virus results from i) its easy spread by aerosol, ii) its ability to escape from protective immunity, and iii) the periodic emergence of new, virulent strains of the virus. For these reasons, the National Institutes of Health has designated influenza infection as a top priority area for biodefense. RNA interference (RNAi) is a process by which double-stranded RNA directs sequence-specific degradation of messenger RNA in animal and plant cells. Studies have shown that RNAi can be triggered by synthetic 21-nucleotide duplexes of small interfering RNA (siRNA) molecules. This project proposes to investigate siRNAs in both preventing and treating influenza virus infection. Specifically, we propose to i) identify siRNAs that potently inhibit influenza virus production in cultured cells, ii) develop systems for efficient delivery of siRNAs into cells of the upper respiratory tract and the lung, where influenza infection normally occurs, iii) investigate the in vivo efficacy of siRNA inhibition of influenza infection in mice, and iv) elucidate the mechanisms by which siRNAs inhibit influenza virus production. Results obtained from the proposed studies may provide a basis for further development of siRNAs as prophylaxis and therapy of influenza virus infection in humans. Theoretically, an siRNA-based treatment should remain effective even with the emergence of new strains of the virus.