VPS34 inhibitors as SARS-CoV-2 antivirals

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Summary SARS-CoV-2, a Betacoronavirus genus, is an enveloped positive-sense, RNA virus responsible for a current pandemic. Because of its profound impact on society and human health there is an urgent need to understand SARS-CoV-2 replication requirements and to identify therapeutic strategies. Repurposing drugs developed for other purposes may provide a shortcut to therapeutic development. The use of compounds known to target specific host factors may also elucidate key pathways needed for virus replication. Coronavirus (CoV) replication involves multiple critical interactions with host cell membranes. One of the most striking features of CoV infection is the establishment of membrane-associated replication organelles that serve as the main sites of viral RNA synthesis. The origin of these membrane organelles is incompletely understood. Because the specific host pathways required for SARS-CoV-2 replication organelle formation are not defined, we asked whether SARS-CoV-2 is susceptible to modulators of lipid metabolism by assessing the sensitivity of the virus to VPS34 inhibitors of VPS34, a lipid kinase required for autophagy and endosomal trafficking; Triacsin C, an inhibitor of long chain fatty acyl CoA synthetase (ACSL) and Orlistat, an inhibitor of fatty acid synthase (FASN). Our preliminary data indicate that inhibitors of VPS34 potently inhibited SARS-CoV-2 replication, whereas an FDA- approved inhibitor of a different class of PI3K had minimal effect on replication. Targeting FASN and ACSL also impairs SARS-CoV-2 replication. These data suggest that VPS34, ACSL and FASN play important roles in replication center formation and virus growth and suggest these enzymes as therapeutic targets. We will test the hypothesis that VPS34, ACSL and FASN are critical for SARS-Cov-2 infection by evaluating additional small molecule inhibitors of these enzymes and by measuring SARS-CoV-2 replication in genetic knockdowns or knockouts of these host enzymes. We will define mechanisms of inhibition and test the hypothesis that generation of membrane-associated viral replication centers will be disrupted. Finally, we will assess the in vivo efficacy of VSP34 inhibitor PIK-III and systemically administered Orlistat in SARS-coV-2- infected hamsters to evaluate the therapeutic potential of inhibitors of lipid metabolism.