Administrative Supplement to R21: Mechanism and in vivo activity of novel glycan-based therapy against flavivirus endothelial permeability and vascular leak

Supplement to R21: Mechanism and in vivo activity of novel glycan-based therapy against flavivirusendothelial permeability and vascular leakEvaluation of therapeutics targeting SARS-CoV-2 infection and defining pathogenic mechanisms ofSARS-CoV-2-triggered pulmonary dysfunctionAbstractThe emerging severe acute respiratory syndrome-corona virus 2 (SARS-CoV-2), the causative agent ofcoronavirus disease 2019 (COVID-19), is spreading rapidly across the world, already affecting 199 countries,and predicted to infect up to 60% of the population, with a ~4.4% case fatality rate to date. Novel therapeuticsare desperately needed, and as we are currently investigating anti-flavivirus properties of cyclodextrincompounds (CDs), which have broad antiviral activity, we propose here to expand this investigation to test thesecompounds for anti-SARS-CoV-2 activity in human bronchial epithelial cells (Aim 1). First, we will fast-track theFDA-approved CDs in our collection, and then screen the rest. OSC Dr. Ralph Baric (UNC) will confirm our mostpromising candidates in primary human cells and collaborate on setting up further studies to test them in hismouse models. Based on previous literature and data acquired through the parent grant, we hypothesize thatthese compounds may have direct virucidal activity by inactivating virions, as well as potentially inhibiting cellattachment by blocking the SARS-CoV-2 spike glycoprotein (S) from interacting with glycans and/or the viralreceptor angiotensin converting enzyme 2 (ACE2) on the cell surface. Though infected patients succumb toacute respiratory distress syndrome (ARDS) involving vascular leak, the viral triggers of this pathology areunclear. Experiments with SARS-CoV-1 found that internalization of ACE2 along with virus particles uponinfection reduces ACE2 levels on the cell surface, resulting in increased angiotensin II activity. The angiotensinII activity is believed to result in upregulation of vasoactive molecules such as vascular endothelial growth factorF (VEGF) and disruption of intercellular junctions, both inducing vascular leak. In Aim 2, our optimized systemfor the study of endothelial cell dysfunction, resulting from many years of work with flaviviruses and included inthe parent grant, will be applied to investigate SARS-CoV-2 vascular pathology induced by the viral S proteinand secondary mediators like VEGF. As we have already observed in vitro anti-leak as well as antiviral propertiesfor some of the tested CDs, we also propose to test these candidates as therapeutics to treat COVID-19 diseasemanifestations. As such, this supplemental grant proposal has the potential to define triggers of SARS-CoV-2 S-mediated vascular leak, contributing to ARDS, as well as testing CDs as therapeutics targeting viral infectiondirectly and indirectly via downstream pathogenesis. FDA-approved CDs and derivatives that prove to beeffective as COVID-19 treatments have the potential to be rapidly developed for potential use in patients.1