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Chen K, Krischuns T, Varga L, Harigua-Souiai E, Paisant S, Zettor A, Chiaravalli J, Delpal A, Courtney D, O'Brien A, Baker S, Decroly E, Isel C, Agou F, Jacob Y, Blondel A, Naffakh N. A highly sensitive cell-based luciferase assay for high-throughput automated screening of SARS-CoV-2 nsp5/3CLpro inhibitors. Antiviral Res 2022; 201:105272. [PMID: 35278581 PMCID: PMC8906008 DOI: 10.1016/j.antiviral.2022.105272] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Revised: 02/19/2022] [Accepted: 02/23/2022] [Indexed: 12/15/2022]
Abstract
Effective drugs against SARS-CoV-2 are urgently needed to treat severe cases of infection and for prophylactic use. The main viral protease (nsp5 or 3CLpro) represents an attractive and possibly broad-spectrum target for drug development as it is essential to the virus life cycle and highly conserved among betacoronaviruses. Sensitive and efficient high-throughput screening methods are key for drug discovery. Here we report the development of a gain-of-signal, highly sensitive cell-based luciferase assay to monitor SARS-CoV-2 nsp5 activity and show that it is suitable for the screening of compounds in a 384-well format. A benefit of miniaturisation and automation is that screening can be performed in parallel on a wild-type and a catalytically inactive nsp5, which improves the selectivity of the assay. We performed molecular docking-based screening on a set of 14,468 compounds from an in-house chemical database, selected 359 candidate nsp5 inhibitors and tested them experimentally. We identified two molecules which show anti-nsp5 activity, both in our cell-based assay and in vitro on purified nsp5 protein, and inhibit SARS-CoV-2 replication in A549-ACE2 cells with EC50 values in the 4–8 μM range. The here described high-throughput-compatible assay will allow the screening of large-scale compound libraries for SARS-CoV-2 nsp5 inhibitors. Moreover, we provide evidence that this assay can be adapted to other coronaviruses and viruses which rely on a viral protease.
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Chen KY, Krischuns T, Ortega Varga L, Harigua-Souiai E, Paisant S, Zettor A, Chiaravalli J, Courtney D, O’Brien A, Baker SC, Isel C, Agou F, Jacob Y, Blondel A, Naffakh N. A highly sensitive cell-based luciferase assay for high-throughput automated screening of SARS-CoV-2 nsp5/3CLpro inhibitors. bioRxiv 2021:2021.12.18.473303. [PMID: 34981051 PMCID: PMC8722588 DOI: 10.1101/2021.12.18.473303] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Effective drugs against SARS-CoV-2 are urgently needed to treat severe cases of infection and for prophylactic use. The main viral protease (nsp5 or 3CLpro) represents an attractive and possibly broad-spectrum target for drug development as it is essential to the virus life cycle and highly conserved among betacoronaviruses. Sensitive and efficient high-throughput screening methods are key for drug discovery. Here we report the development of a gain-of-signal, highly sensitive cell-based luciferase assay to monitor SARS-CoV-2 nsp5 activity and show that it is suitable for high-throughput screening of compounds in a 384-well format. A benefit of miniaturisation and automation is that screening can be performed in parallel on a wild-type and a catalytically inactive nsp5, which improves the selectivity of the assay. We performed molecular docking-based screening on a set of 14,468 compounds from an in-house chemical database, selected 359 candidate nsp5 inhibitors and tested them experimentally. We identified four molecules, including the broad-spectrum antiviral merimepodib/VX-497, which show anti-nsp5 activity and inhibit SARS-CoV-2 replication in A549-ACE2 cells with IC 50 values in the 4-21 µM range. The here described assay will allow the screening of large-scale compound libraries for SARS-CoV-2 nsp5 inhibitors. Moreover, we provide evidence that this assay can be adapted to other coronaviruses and viruses which rely on a viral protease.
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Affiliation(s)
- KY Chen
- RNA Biology and Influenza Virus Unit, Institut Pasteur, CNRS UMR3569, Université de Paris, Paris, France
| | - T Krischuns
- RNA Biology and Influenza Virus Unit, Institut Pasteur, CNRS UMR3569, Université de Paris, Paris, France
| | - L Ortega Varga
- Structural Bioinformatics Unit, Institut Pasteur, Université de Paris, Paris, France
| | - E Harigua-Souiai
- Laboratory of Molecular Epidemiology and Experimental Pathology – LR16IPT04, Institut Pasteur de Tunis, Université de Tunis El Manar, Tunis, Tunisia
| | - S Paisant
- RNA Biology and Influenza Virus Unit, Institut Pasteur, CNRS UMR3569, Université de Paris, Paris, France
| | - A Zettor
- Chemogenomic and Biological Screening Platform, Institut Pasteur, Université de Paris, Paris, France
| | - J Chiaravalli
- Chemogenomic and Biological Screening Platform, Institut Pasteur, Université de Paris, Paris, France
| | - D Courtney
- RNA Biology and Influenza Virus Unit, Institut Pasteur, CNRS UMR3569, Université de Paris, Paris, France
| | - A O’Brien
- Department of Microbiology and Immunology, Loyola University Chicago, Stritch School of Medicine, Maywood, IL, USA
| | - SC Baker
- Department of Microbiology and Immunology, Loyola University Chicago, Stritch School of Medicine, Maywood, IL, USA
| | - C Isel
- RNA Biology and Influenza Virus Unit, Institut Pasteur, CNRS UMR3569, Université de Paris, Paris, France
| | - F Agou
- Chemogenomic and Biological Screening Platform, Institut Pasteur, Université de Paris, Paris, France
| | - Y Jacob
- Molecular Genetics of RNA Viruses, Institut Pasteur, CNRS UMR3569, Université de Paris, Paris, France
| | - A Blondel
- Structural Bioinformatics Unit, Institut Pasteur, Université de Paris, Paris, France
| | - N Naffakh
- RNA Biology and Influenza Virus Unit, Institut Pasteur, CNRS UMR3569, Université de Paris, Paris, France
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