Blocking pyroptosis to prevent acute lung injury in SARS-CoV-2 infection

Human infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can induce 2019coronavirus disease (COVID-19), which progresses to acute respiratory distress syndrome and death in asignificant proportion of patients. As outlined in the Notice of Special Interest NOT-AI-20-030, there is a criticallack of understanding of many fundamentals of COVID-19. It is urgent that we determine the mechanism ofacute lung injury caused by SARS-CoV-2 infection and how this might be prevented therapeutically. Many linesof investigation suggest that acute respiratory distress syndrome experienced in severe COVID-19 is due to anoverwhelming host innate immune response. This provides an opportunity to block the innate responsetherapeutically and offset severe disease. Lethal COVID-19 is associated with marked lung inflammation andalveolar disruption, suggesting that alveolar cells die by pyroptosis, an intensely inflammatory form of celldeath. Pyroptosis is mediated by activated inflammatory caspases and cleaved gasdermin D (GSDMD), andpharmacologic inhibitors of these two essential factors have been developed. Based on these findings, wehypothesize that acute lung injury caused by SARS-CoV-2 infection in humans is mediated by intenseinflammation and pyroptosis, and that inhibitors of inflammatory caspases and GSDMD will block lung damage.Importantly, the PI has federal and university clearance to work with highly pathogenic viruses such as SARS-CoV-2 in the University of Pittsburgh's Regional Biocontainment Laboratory, where he has exclusive use of alaboratory suite. We will use precision-cut human lung slices, which are a powerful tool to study pathogenichuman viruses in the context of the intact, human lung. We are already using this system to evaluate acutelung injury caused by highly pathogenic avian influenza (H5N1), which causes acute respiratory distresssyndrome in humans similar to severe COVID-19. We have recently found that alveolar cells infected withH5N1 influenza die by pyroptosis which is prevented by VX-765 and disulfiram, inhibitors of caspase-1/4 andGSDMD, respectively. Notably, both drugs have been shown to be safe in humans. Disulfiram in particular iswidely used to treat other human conditions and is extremely cheap and readily available. In this proposal, wewill first determine the cellular targets of SARS-CoV-2 infection in human lung, and then determine howalveolar cells die following infection. We will then determine if innate immune inhibitors targeting caspase-1/4and GSDMD prevent alveolar cell damage. If we determine that acute lung injury caused by SARS-CoV-2 isprevented by VX-765 and disulfiram, our study would justify the clinical use of these drugs to prevent severeCOVID-19 in this expanding pandemic, which would be a major public health breakthrough.