Although COVID-19 is recognized primarily as a respiratory infection and the majority of deaths from the disease are attributed to pulmonary failure, it has become increasingly apparent that the SARS-CoV-2 virus, either directly or indirectly, affects all major organ systems with a confounding degree of variability that complicates the identification of effective therapeutics. In particular, the central nervous system (CNS) and vasculature both seem to play a significant role in disease progression, and CNS symptoms have correlated with poorer outcomes in COVID-19 patients. It is hypothesized that the CNS and vasculature each influence pathological dysregulation of immune response, but very little is known about how they respond and possibly contribute to disease progression. No single therapeutic agent has emerged that broadly neutralizes COVID-19 disease progression, which strongly suggests that any effective treatment strategies will need to address not only effects of SARS-CoV-2 infection in the lungs, but also inflammation in many organ systems, which in turn would require therapeutic access to the CNS. Thus, understanding the interactions between the lungs and the CNS is critical to identifying treatments capable of improving the prognoses of COVID-19 patients and reducing hospitalization rates and mortality. This project will evaluate how SARS-CoV-2 infection in the lungs contributes to both the organ dysfunction in COVID-19 and potential CNS infection, and how well the combination of anti-viral and anti-inflammatory drugs addresses CNS involvement in COVID-19. These goals demand a physiologically relevant in vitro platform that fully recapitulates the systemic immune and cytokine storm responses following infection of airway epithelium associated with the most severe cases of COVID-19 and that can be readily used in the Biosafety Level-3 (BSL-3) facilities required for studies of this highly infectious respiratory disease. This project will implement a two-organ microphysiological system (MPS) model that uses an existing NeuroVascular Unit (NVU)/blood-brain barrier tissue chip for the CNS component, repurposes the NVU as an Airway Chip for the lung component, and converts both chips to gravity perfusion for ease of use in BSL-3 facilities. The aims are to 1) model COVID-19 infection and innate pulmonary response in the Airway Chip, 2) couple the NVU and Airway Chip to evaluate how the response of the Airway Chip to COVID-19 infection affects the function of the NVU, as required to establish therapeutic benchmarks for drug testing, and 3) screen FDA-approved drugs for efficacy in treating negative symptoms in the NVU/Airway Chip model. A comparison of infection of the separate NVU/CNS and Airway tissue chips with infection of the coupled-chip system will help determine the infectability of each MPS model and the viral capacity to cross the blood-brain barrier into the CNS. Candidate FDA-approved drugs will be tested for their ability to affect viral infection, replication, and cytokine production in both microphysiological systems.

As research on COVID-19 has grown during the pandemic, the effects of the SARS-CoV-2 virus on not only the respiratory system, but on all major organ systems, are being recognized, with central nervous system (CNS) symptoms especially correlated with poor outcomes in COVID-19 patients. No single therapeutic agent has emerged that broadly neutralizes COVID-19 disease progression, which strongly suggests that any effective treatment strategies will need to address the effects of SARS-CoV-2 infection in the lungs and inflammation in many organ systems, which in turn would require therapeutic access to the CNS. Thus, understanding the interactions between the lungs and the CNS is critical to identifying treatments capable of improving the prognoses of COVID-19 patients and reducing hospitalization rates and mortality.