WEST NILE VIRUS PERTURBS NEURAL FUNCTIONS THROUGH SYNAPTIC REMODELING AND DOWNSTREAM SIGNALING INTERFERENCE

West Nile virus (WNV) is an emerging arbovirus causing acute encephalitis and long-term neurological and cognitive deficits. While neuroinflammatory contributions to WNV neuroinvasive disease have been largely investigated, the molecular mechanisms underlying virus-induced perturbations of synaptic functions and plasticity remain to be understood. Importantly, the absence of severe neurological symptoms does not rule out neuroinvasion, subtle neuropathogenesis or viral interference with neuronal signaling. The molecular mechanisms underlying WNV-induced neuronal dysfunctions need to be further explored using physiologically relevant human-based models. Here, we show that the organotypic culture of post-mortem adult human brain (OPAB) explants represents a relevant WNV infection model ex vivo. Synaptosome isolation from infected OPABs for differential proteomic analyses enabled comprehensive profiling of WNV-induced synaptic proteome remodeling. Specifically, WNV significantly dysregulates the expression of proteins involved in synaptic architecture, plasticity and neurotransmission. The functional consequences of WNV perturbations on neural activity using microelectrode arrays revealed that WNV exposure interferes with network connectivity. Moreover, we show that WNV infection of neurons interferes with synaptic signaling pathways, leading to basal overexpression of several immediate early genes (IEGs) and impairs induction in IEGs transcription following glutamate stimulation. Together, our findings provide novel mechanistic insights about the molecular impact of WNV on synapse homeostasis and associated electrophysiological perturbations. The OPAB model provides a unique platform to study cognitive virology by integrating the molecular and functional features of the human brain in-a-dish.