Bioengineering a human microphysiological system for elucidation of viral peripheral neurotropism of RSV and SARS-CoV-2 - PROJECT SUMMARY Chronic neurological impairments are a widespread consequence of both the SARS-CoV-2 pandemic and the subsequent surge in RSV that will place a lasting burden on healthcare systems worldwide. This includes both purely cognitive symptoms (sleep disruption, confusion, and brain fog) as well as symptoms of peripheral and autonomic neuropathy (shortness of breath, intractable cough, headache, and stroke). While the blood-brain barrier protects central nervous system (CNS), the peripheral nervous system (PNS) is more directly exposed to pathogens both in the nerve terminals innervating the upper respiratory tract and through the general circulation. Unfortunately, viral invasion of the PNS is vastly understudied despite its constant exposure to pathogens and critical role in the regulation of normal bodily functions. Using innovative neural microphysiological systems (MPSs), we have recently demonstrated that RSV infects both monocytes and neurons in peripheral nerve tissue, generates concerted chemokine release, and dose-dependently induces nerve hypersensitization or progressive neurotoxicity. Both neuronal infection and inflammation-mediated neuropathy are novel observations that could explain analogous mechanisms of peripheral neuroinvasion in humans that may contribute to sudden apnea experienced by infants exposed to RSV in utero, chronic airway hyperreactivity in children exposed to RSV in the perinatal period, and the persistent peripheral neuropathy and autonomic dysfunction associated with long COVID. Critically, MPSs support the use of rodent, human stem cell-derived, or primary cell types within the same model system, facilitating comparison of analogous data across species towards translation of basic research findings to the clinic. The development of bioengineered models of the PNS and likewise the methodologies necessary for efficient, repeatable data extraction specifically from microphysiological peripheral nerve has received considerably less attention than analogous models of the CNS. Here we propose to establish the conditions necessary to facilitate interaction between peripheral neurons, glia, and inflammatory cells in microphysiological culture to advance the meaningful complexity of microphysiological PNS modeling. We also aim to identify the most stable and sensitive optogenetic tools for long-term longitudinal collection of neurophysiological data to maximize the utility of this MPS for detection of viral neuropathy. We will then demonstrate the utility of the system by using it to compare peripheral neuropathy resulting from direct exposure to RSV and SARS-CoV-2. Completion of these goals will establish the feasibility of a novel, human- based MPS capable of elucidating peripheral neurotropism of known and emerging viruses.
