Shepley-McTaggart, A. | bioRxiv Science

bioRxiv2021

Compound FC-10696 Inhibits Egress and Spread of Marburg Virus

Marburg virus (MARV) VP40 protein (mVP40) directs egress and spread of MARV, in part, by recruiting specific host WW-domain containing proteins via its conserved PPxY Late (L) domain motif to facilitate efficient virus-cell separation. We reported previously that small molecule compounds targeting the viral PPxY/host WW-domain interaction inhibited VP40-mediated egress and spread. Here, we report on the antiviral potency of novel compound FC-10696, which emerged from extensive structure activity relationship (SAR) of a previously described series of PPxY inhibitors. We show that FC-10696 inhibits egress of both mVP40 VLPs and egress and spread of authentic MARV from HeLa cells and primary human macrophages. Moreover, FC-10696 treated mice displayed delayed onset of weight loss, clinical signs, and significantly lower viral loads compared to controls, with 14% of animals surviving 21 days following a lethal MARV challenge. Thus, FC-10696 represents a first-in-class, host-oriented inhibitor effectively targeting late stages of the MARV lifecycle.

microbiology↗

bioRxiv2020

SARS-CoV-2 Envelope (E) Protein Interacts with PDZ-Domain-2 of Host Tight Junction Protein ZO1

Newly emerged SARS-CoV-2 is the cause of an ongoing global pandemic leading to severe respiratory disease in humans. SARS-CoV-2 targets epithelial cells in the respiratory tract and lungs, which can lead to amplified chloride secretion and increased leak across epithelial barriers, contributing to severe pneumonia and consolidation of the lungs as seen in many COVID-19 patients. There is an urgent need for a better understanding of the molecular aspects that contribute to SARS-CoV-2-induced pathogenesis and for the development of approaches to mitigate these damaging pathologies. The multifunctional SARS-CoV-2 Envelope (E) protein contributes to virus assembly/egress, and as a membrane protein, also possesses viroporin channel properties that may contribute to epithelial barrier damage, pathogenesis, and disease severity. The extreme C-terminal (ECT) sequence of E also contains a putative PDZ-domain binding motif (PBM), similar to that identified in the E protein of SARS-CoV-1. Here, we screened an array of GST-PDZ domain fusion proteins using either a biotin-labeled WT or mutant ECT peptide from the SARS-CoV-2 E protein. Notably, we identified a singular specific interaction between the WT E peptide and the second PDZ domain of human Zona Occludens-1 (ZO1), one of the key regulators of TJ formation/integrity in all epithelial tissues. We used homogenous time resolve fluorescence (HTRF) as a second complementary approach to further validate this novel modular E-ZO1 interaction. We postulate that SARS-CoV-2 E interacts with ZO1 in infected epithelial cells, and this interaction may contribute, in part, to tight junction damage and epithelial barrier compromise in these cell layers leading to enhanced virus spread and severe respiratory dysfunction that leads to morbidity. Prophylactic/therapeutic intervention targeting this virus-host interaction may effectively reduce airway barrier damage and mitigate virus spread.

microbiology↗