PROJECT SUMMARY/ABSTRACT (Project 3) Zoonotic coronaviruses (CoV) are responsible for three major epidemics/pandemics in the 21st century, including Severe Acute Respiratory Coronavirus (SARS-CoV) in 2003 and Middle East Respiratory coronavirus (MERS- CoV) in 2012. In Dec 2019, a third novel coronavirus (CoV) designated SARS-CoV-2 emerged in Wuhan China and in the space of 5 months, has caused over 6.5 million cases, >300,000 deaths in >200 countries. Over 1/3 of these total cases have been reported in the US, resulting in over 100,000 deaths. In humans, virus infection results in COVID-19 disease, characterized by pneumonia and severe acute respiratory distress syndrome (ARDS), an often fatal end-stage lung disease. In addition to SARS-CoV2, multiple other SARS-like and MERS- like CoV strains reside in bats and other species and are poised to emerge at some point in the future. We have little understanding of the tropism and host signaling networks associated with epidemic and pre-epidemic emerging coronavirus infections in the human lung and other organs. Moreover, the SARS-CoV-2 virus-host interaction networks associated with virus replication in the lung and their association with chronic disease manifestations in vivo remain unknown. We propose to take advantage of recent technological advances in human tissue engineering to mimic virus infection of mucosal surfaces. The overall goal of this proposal is to study the interaction networks with associated with emerging coronavirus infection of primary lung organoid cultures. We will focus on previously difficult-to-model critical problems, such as virus tropism, virus-host interaction networks in within and between patient codes and innate immune activation in the airway epithelium and surrounding tissues. The proposal also relies on mouse organoid cultures and models of human disease, promoting an integrated platform to identify highly efficacious small molecule inhibitors in vitro and in vivo. Aim 1 establishes SARS-CoV-2 infection conditions in human lung organoids. Aim 2 investigates SARS-CoV-2- stimulated epithelial-immune interactions in lung ALI organoids. Aim 3 development of lung organoid cultures for SARS-CoV-2 therapeutics screening.