Search bioRxiv⌕ Search

Biology subjects

Lavie, M.

Publications and source records attributed to Lavie, M..

2 recordsLinked to original sources
bioRxiv2022

Biosynthetic proteins targeting the SARS-CoV-2 spike as anti-virals

The binding of the SARS-CoV-2 spike to angiotensin-converting enzyme 2 (ACE2) promotes virus entry into the cell. Targeting this interaction represents a promising strategy to generate antivirals. By screening a phage-display library of biosynthetic protein sequences build on a rigid alpha-helicoidal HEAT-like scaffold (named Reps), we selected candidates recognizing the spike receptor binding domain (RBD). Two of them (F9 and C2) bind the RBD with affinities in the nM range, displaying neutralisation activity in vitro and recognizing distinct sites, F9 overlapping the ACE2 binding motif. The F9-C2 fusion protein and a trivalent Rep form (C2-foldon) display 0.1 nM affinities and EC50 of 8-18 nM for neutralization of SARS-CoV-2. In hamsters, F9-C2 instillation in the nasal cavity before or during infections effectively reduced the replication of a SARS-CoV-2 strain harbouring the D614G mutation in the nasal epithelium. Furthermore, F9-C2 and/or C2-foldon effectively neutralized SARS-CoV-2 variants (including delta and omicron variants) with EC50 values ranging from 13 to 32 nM. With their high stability and their high potency against SARS-CoV-2 variants, Reps provide a promising tool for SARS-CoV-2 therapeutics to target the nasal cavity and mitigate virus dissemination in the proximal environment. Author SummaryThe entry of SARS-CoV-2 in permissive cells is mediated by the binding of its spike to angiotensin-converting enzyme 2 (ACE2) on the cell surface. To select ligands able to block this interaction, we screened a library of phages encoding artificial proteins (named Reps) for binding to its receptor binding domain (RBD). Two of them were able to bind the RBD with high affinity and block efficiently the virus entry in cultured cells. Assembled Reps through covalent or non-covalent linkages blocked virus entry at lower concentration than their precursors (with around 20-fold activity increase for a trimeric Rep). These Reps derivates neutralize efficiently SARS-CoV-2 {beta}, {gamma}, {delta} and Omicron virus variants. Instillation of an Rep dimer in the nasal cavity effectively reduced virus replication in the hamster model of SARS-CoV-2 and pathogenicity.

microbiology↗
bioRxiv2018

Dehydrojuncusol, a Natural Phenanthrene Compound Extracted from Juncus maritimus Is a New Inhibitor of Hepatitis C Virus Replication

Recent emergence of direct acting antivirals (DAAs) targeting hepatitis C virus (HCV) proteins has considerably enhanced the success of antiviral therapy. However, the appearance of DAA resistant-associated variants is a cause of treatment failure, and the high cost of DAAs renders the therapy not accessible in countries with inadequate medical infrastructures. Therefore, search for new inhibitors and with lower cost of production should be pursued. In this context, crude extract of Juncus maritimus Lam. was shown to exhibit high antiviral activity against HCV in cell culture. Bio-guided fractionation allowed isolating and identifying the active compound, dehydrojuncusol. A time-of-addition assay showed that dehydrojuncusol significantly inhibited HCV infection when added after virus inoculation of HCV genotype 2a (EC50 = 1.35 {micro}M). This antiviral activity was confirmed with a HCV subgenomic replicon and no effect on HCV pseudoparticle entry was observed. Antiviral activity of dehydrojuncusol was also demonstrated in primary human hepatocytes. No in vitro toxicity was observed at active concentrations. Dehydrojuncusol is also efficient on HCV genotype 3a and can be used in combination with sofosbuvir. Interestingly, dehydrojuncusol was able to inhibit replication of two frequent daclatasvir resistant mutants (L31M or Y93H in NS5A). Finally, resistant mutants to dehydrojuncusol were obtained and showed that HCV NS5A protein is the target of the molecule. In conclusion, dehydrojuncusol, a natural compound extracted from J. maritimus, inhibits infection of different HCV genotypes by targeting NS5A protein and is active against HCV resistant variants frequently found in patients with treatment failure.\n\nImportanceTens of millions of people are infected with hepatitis C virus (HCV) worldwide. Recently marketed direct acting antivirals (DAAs) targeting HCV proteins have enhanced the efficacy of the treatment. However, due to its high cost, this new therapy is not accessible to the vast majority of infected patients. Furthermore, treatment failures have also been reported due to appearance of viral resistance. Here we report on the identification of a new HCV inhibitor, dehydrojuncusol that targets HCV NS5A and is able to inhibit replication of replicons harboring resistance mutations to anti-NS5A \nDAAs used in current therapy. Dehydrojuncusol is a natural compound isolated from Juncus maritimus, a halophilic plant species very common in the coastlines worldwide. This molecule might serve as a lead for the development of new therapy more accessible to hepatitis C patients in the future.

microbiology↗