Abstract 2272 Structure Determination of MO14 Enterovirus D68 Mutation

The recent increase in Enterovirus D68 (EV-D68) outbreaks has made the search for effective therapeutics a crucial endeavor. EV-D68, a member of the Picornaviridae family, is a respiratory virus of concern due to its ability to cause Acute Flaccid Myelitis, a neurological condition like poliomyelitis that can lead to permanent paralysis. EV-D68 has an icosahedral capsid composed of 60 protomers, the capsid building blocks are made from a single copy of each structural protein VP1-VP4. Within VP1 is a hydrophobic pocket often targeted for capsid binding inhibitors. Pleconaril, one such inhibitor, binds within the hydrophobic pocket leading to capsid stabilization and prevention of viral infection. Recently, an EV-D68 MO14 Pleconaril resistant mutant strain was provided to us by our collaborator Dr. Jun Wang. This project aims to compare wild type MO14 (WT MO14) to this mutant MO14 strain using both structural and functional techniques. Based on the resistance of this mutant to Pleconaril, we hypothesize that this viral mutant MO14 has reduced capsid stability that ultimately leads to decreased viral infectivity. The mutant MO14 structure was first determined using Cryo-EM imaging. Genome loaded, partially empty, and disassembled particles were visualized suggesting a capsid stability defect. Further analysis of virus growth capacity by one-step and multi-step growth assays showed that there is reduced virus growth as indicated by titer reduction in plaque assay analysis. Thermal stability assays were also done in the presence and absence of Pleconaril to study capsid stability. This study showed that the mutant EV-D68 MO14 is unstable as indicated by reduced viral titer at lower temperatures than WT MO14. However, Pleconaril treatment increases mutant MO14 stability and infectivity. These preliminary studies suggest that in the presence of pleconaril, the mutant MO14 gains stability that allows it to survive higher temperatures compared to WT MO14. Further understanding of how this Pleconaril resistant mutant MO14 strain alters capsid dynamics can help aid in the creation of more targeted drug therapies. I would like to thank Dr. Kuhn for hosting me in his lab, and Jacqueline Anderson and Dr. Klose for mentoring me the past ten weeks. Collaborations: Dr. Jun Wang at Rutgers University for providing MO14 EV-D68 Funding: NSF Grant for REU in SCBB at Purdue University research award number: 2150396 Dr. Kuhn funding lab experiments