"Survivor" neurons drive persistent inflammation following West Nile virus infection

Project Summary/Abstract- "Survivor" neurons drive persistent inflammation following West Nile virus infection West Nile virus (WNV) is mosquito-borne flavivirus that can infect neurons of the central nervous system. Both human patients murine model organisms that survive neuroinvasive WNV display learning, memory and motor sequelae that persist long after the virus is cleared. While these sequelae have been associated with persistent inflammation within the CNS, the source of this inflammation has remained obscure. Previous studies by our group and others have revealed that neurons are remarkably resistant to programmed cell death in response to multiple stressors, including viral infection. This observation led us to hypothesize that neurons that are infected with WNV but survive and clear infection-"survivor" neurons- sustain virus-induced changes that drive long-term inflammation and CNS disfunction. We sought to test this idea by creating a recombinant clone of WNV that expresses Cre recombinase, then using this virus to mark "survivor" neurons in the brains of WNV-infected mice. Spatial transcriptomic analysis of these cells revealed that "survivor" neurons maintain a robust inflammatory signature weeks after viral infection is cleared. Strikingly, this signature is absent in adjacent, WNV-naïve neurons within the same tissues, supporting the idea that "survivor" neurons are drivers of persistent CNS inflammation. The goal of the work proposed here is to use this newly-developed model to first understand the changes to "survivor" neurons that drive persistent inflammation, and second to assess the consequences of this inflammatory response on the function of these neurons, on nearby cells and on organismal learning and memory. We suggest that the use of these new models and emerging technologies will provide important insight into CNS disfunction caused by WNV infection. We further suggest that this insight may be applicable to long-term virus-induced inflammatory dysfunction in other settings.