A viral assembly inhibitor blocks SARS-CoV-2 replication in airway epithelial cells

Abstract

The ongoing evolution of SARS-CoV-2 to evade vaccines and therapeutics underlines the need for innovative therapies with high genetic barriers to resistance. Therefore, there is pronounced interest in identifying new pharmacological targets in the SARS-CoV-2 viral life cycle. The small molecule PAV-104, identified through a cell-free protein synthesis and assembly screen, was recently shown to target host protein assembly machinery in a manner specific to viral assembly. In this study, we investigate the capacity of PAV-104 to inhibit SARS-CoV-2 replication in human airway epithelial cells (AECs). We show that PAV-104 inhibits >99% of infection with diverse SARS-CoV-2 variants in immortalized AECs, and in primary human AECs cultured at the air-liquid interface (ALI) to represent the lung microenvironment in vivo. Our data demonstrate that PAV-104 inhibits SARS-CoV-2 production without affecting viral entry, mRNA transcription, or protein synthesis. PAV-104 interacts with SARS-CoV-2 nucleocapsid (N) and interferes with its oligomerization, blocking particle assembly. Transcriptomic analysis reveals that PAV-104 reverses SARS-CoV-2 induction of the type-I interferon response and the maturation of nucleoprotein signaling pathway known to support coronavirus replication. Our findings suggest that PAV-104 is a promising therapeutic candidate for COVID-19 with a mechanism of action that is distinct from existing clinical management approaches.

A pan-respiratory antiviral chemotype targeting a transient host multi-protein complex

“…When administered to rats, a dose of 5 mg kg −1 administered intraperitoneally (IP) was found to be safe, reaching a concentration of 108 nM in plasma and 167 nM in lungs (see electronic supplementary material, figure S5 a ). The following findings were obtained from a pharmacokinetics comparison between the earlier compound PAV-431 and a more advanced compound of the same lead series, PAV-104 [ 48 ]. From the electronic supplementary material, figure S5 a , it is evident that PAV-104 had a better PK profile than PAV-431.…”

“…However the antiviral activity of compounds from the series have been validated against infectious viruses in both cell culture and animals (see figures 2 and 3 and electronic supplementary material, figure S1). The cell culture studies include primary bronchial epithelial cells cultured at an air–liquid interface and infected with SARS-CoV-2, a model considered as the gold standard for translatability into human therapeutics [ 81 ], which have confirmed the antiviral potency of these compounds (see figure 3 and [ 48 ]). Animal studies validated efficacy for survival in an actual pig coronavirus disease and viral load reduction in the cotton rat model of RSV infection (see electronic supplementary material, figure S1 and figure 4 ).…”