EV-D68 genetic neuropathogenesis determinants

EV-D68 viral determinants of neuropathogenesis in a human model Enterovirus D68 (EV-D68) is a non-polio enterovirus discovered in 1962 as a cause of respiratory illness in children. EV-D68 is considered a reemerging pathogen due to increased respiratory disease severity, circulation, and newly recognized neurovirulence over the last decade. EV-D68 has been implicated in acute flaccid myelitis (AFM), a polio-like illness, often in previously healthy children, for which there are currently no treatments or vaccines. Mechanisms for how EV-D68 targets the central nervous system (CNS) to mediate paralysis are unknown, partially due to lack of human model systems. The human spinal cord organoid model (hSCO) for EV-D68 infection contains multiple cell types, including neurons and glial cells. This recently developed hSCO model can be infected with EV-D68 strains that emerged after 2014, but not older EV-D68 isolates, corresponding to the neurotropism noted with recent clinical presentations. Prior studies of EV-D68 genetic neuropathogenesis determinants have focused on a limited number of viral isolates and were exclusively tested in mouse models. This project utilizes recently optimized methods for EV-D68 infectious clone recovery in combination with the novel hSCO model to identify viral genetic determinants of EV-D68 neuropathogenesis. The overarching hypothesis is that EV-D68 neurotropism in humans is primarily driven by recent changes in the structural proteins. This hypothesis will be tested by using the hSCO model to 1) determine viral genetic determinants with a panel of chimeric viruses between the 1962 EV-D68 Fermon strain and neuropathogenic EV-D68 strain US/IL/14-18952 2) assess the hypervariable regions of VP1 and previously described VP1 and VP3 genetic determinants of murine neurotropism 3) and investigate genetic determinants of neurotropism across all EV-D68 clades. Studies in this proposal will define mechanisms of EV-D68 neuropathogenesis in a novel hSCO model by focusing on genetic determinants of neurotropism that have evolved since the initial recognition of EV-D68. In conjunction with existing surveillance platforms, this work will inform neurovirulence potential in each EV-D68 season as well as identify potential targets for therapeutic intervention. Project Number: 1R21AI193384-01 | Fiscal Year: 2025 | NIH Institute/Center: National Institute of Allergy and Infectious Diseases (NIAID) | Principal Investigator: Megan Freeman | Institution: UNIVERSITY OF PITTSBURGH AT PITTSBURGH, PITTSBURGH, PA | Award Amount: $430,170 | Activity Code: R21 | Study Section: Viral Dynamics and Transmission Study Section [VDT] View on NIH RePORTER: https://reporter.nih.gov/project-details/1R21AI19338401