Organ-on-Chip Approach for Assessing Tissue-specific SARS-CoV-2 Infection and Response to Antiviral Therapy

The current COVID-19 pandemic is a worldwide, rapidly developing, health crisis caused by the Severe AcuteRespiratory Syndrome Coronavirus 2 (SARS-CoV-2). As of May 18, 2020, over 4.7 million infections areconfirmed globally and over 315,000 people have died from COVID-19 related complications. Efforts to developand test COVID-19 vaccines are in high gear. In the meantime, there is a dire need for fast and robust in-vitrotests that can be used to study the mechanisms of host-virus interactions and help assess whether existingantivirals could be used against for SARS-CoV-2. Current static 2D cell culture systems and animal-basedmodels are of limited use for these purposes. To address this gap, the proposed project aims to develop organ-on-chip (OOC)-based assays for quantifying SARS-CoV-2 inoculation and replication in three human tissuesthat have been shown to be severely affected by SARS-CoV-2. In order to enable an immediate start, a fasttimeline, and milestones with translational impact, the approach of this supplement will mainly repurpose alreadyexisting, validated, and commercialized OOC models that were developed under the parent grant. AIM1 is todevelop SARS-CoV-2 assays for kidney proximal tubule and vascular endothelium, models that were initiallydeveloped for assessing drug toxicity and drug transport. In addition, an OOC model of the lung alveolus will bedeveloped. SARS-CoV-2 Wuhan Reference Strain, the SARS-CoV-2 Spike Mutation D614G Strain, as well asa Spike-pseudotyped lentivirus will be tested and compared for differences in inoculation rate and replicationrate (AIM2). The assay protocols will include introducing the viruses via the perfusate to the lumen of the tissuestructures in order to bring the virus in contact with the ACE2 and CD 147 receptors that reside on the apicalside of the cell and are responsible for virus binding and subsequent endocytosis. To quantify viral inoculation,the tissues will be removed after a short but adequate incubation period. The viruses will be extracted from thetissues, serially diluted and quantified using plaque assays. In order to assess viral replication, tissues will beharvested from the chips after a pre-determined, longer, incubation period that gives the cells enough time forviral replication. Viral load will be quantified with plaque assays. AIM3 is to use the OOC-based assays for testinga number of candidate antivirals and compare their effect against baseline SARS-COVID-19 virus load. The listof antivirals to be tested includes antibodies against ACE2 and CD147 receptors; RNA polymerase inhibitorRemdesivir; PAMP RNA, a RIG-agonist and interferon inducer; and the antimalarial chloroquine. The dataobtained from the OOC assays will be correlated with pre-existing in-vitro data, animal data, and clinical findings.The technology can be quickly made available to the research community. Models of other tissue structuresaffected by SARS-COVID-19, such as myocardium, intestinal mucosa, and kidney glomerulus can besubsequently added to the portfolio. Further, the models can be tailored to include cells from elderly patients ormimic conditions connected with severe outcomes, such as diabetes, hypertension, or kidney disease.