MicroRNA-based strategy to mitigate the risk of gain-of-function influenza studies

Langlois, Ryan A.; Albrecht, Randy A.; Kimble, Brian; Sutton, Troy; Shapiro, Jillian S.; Finch, Courtney; Angel, Matthew; Chua, Mark A.; Gonzalez-Reiche, Ana Silvia; Xu, Kemin; Perez, Daniel; García-Sastre, Adolfo; tenOever, Benjamin R.

Recent gain-of-function studies in influenza A virus H5N1 strains revealed that as few as three amino-acid changes in the hemagglutinin protein confer the capacity for viral transmission between ferrets(1, 2). As transmission between ferrets is considered a surrogate indicator of transmissibility between humans, these studies raised concerns about the risks of gain-of-function influenza A virus research. Here we present an approach to strengthen the biosafety of gain-of-function influenza experiments. We exploit species-specific endogenous small RNAs to restrict influenza A virus tropism. In particular, we found that the microRNA miR-192 was expressed in primary human respiratory tract epithelial cells as well as mouse lungs but absent from the ferret respiratory tract. Incorporation of miR-192 target sites into influenza A virus did not prevent influenza replication and transmissibility in ferrets, but did attenuate influenza pathogenicity in mice. This molecular biocontainment approach should be applicable beyond influenza A virus to minimize the risk of experiments involving other pathogenic viruses.