Ifenprodil and Flavopiridol Identified by Genome-Wide RNAi Screening As Effective Drugs to Ameliorate Murine Acute Lung Injury after Influenza A H5N1 Virus Infection

Abstract

Background: Due to limits of effective treatments, avian influenza A H5N1 virus is most lethal influenza virus strain that causes severe acute lung injury (ALI). To develop effective drugs ameliorating H5N1-induced ALI, we explore an RNA interference (RNAi) screening method to monitor changes in cell death induced by H5N1 infection. According to estimation of Bernard Munos, a drug-development advocacy organization in Washington DC, the proportion of drugs that in theory could be repositioned is probably approximately 75%. Methods: We screened 19,424 RNAi in A549 lung epithelial cells and examined cell death induced by H5N1 infection. These screenings identified 1137 host genes for which knockdown altered cell viability by over 20%. DrugBank searches of these 1137 host genes identified 146 validated druggable target genes with 372 drug candidates. We obtained 104 commercially available drugs with 65 validated target genes and examined their improvements in cell viability following H5N1 infection. We identified 28 drugs that could significantly recover cell viability following H5N1 infection and tested 10 in an H5N1-induced ALI mouse model. Findings: The neurological drug ifenprodil and anticancer drug flavopiridol markedly decreased infiltrated leukocytes and lung injury scores in infected mouse lungs and significantly ameliorated lung edema in infected mouse lung tissue. Interpretation: Ifenprodil is an antagonist of N-methyl-D-aspartate (NMDA) receptor, which is linked to inflammation and lung injury. Flavopiridol is an inhibitor of CDK4, which is linked to leukocyte migration and lung injury. These results suggest that ifenprodil and flavopiridol are novel remedies against potential H5N1 epidemics in addition to their proven indications. Furthermore, our strategy for identifying repurposable drugs could serve as a general approach for other diseases. Funding Statement: This work was supported by National Natural Science Foundation of China (81788101, 81490531), Ministry of Science and Technology of China (2015CB553406) and CAMS Innovation Fund for Medical Sciences (2017-I2M-1-009). Declaration of Interests: The authors declare that they have no competing interests. Ethics Approval Statement: Animal experiments in this work were approved by Ethics Committee of Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences (ACUC-A02-2017-014).