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Updated: Jul 3, 2025
07:53
A Fluorogenic Peptide Cleavage Assay to Screen for Proteolytic Activity: Applications for coronavirus spike protein activation
Published on: January 9, 2019
33.2K
Calpain-2 mediates SARS-CoV-2 entry via regulating ACE2 levels
Qiru Zeng1, Avan Antia1, Luis Alberto Casorla-Perez2
1Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri, USA.
Mbio
|February 13, 2024
Summary
Calpain inhibitors block severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection by targeting host cell entry, not just viral replication. Calpain-2 facilitates SARS-CoV-2 attachment by regulating ACE2 levels, presenting a new therapeutic target for COVID-19.
Area of Science:
- Virology and Molecular Biology
- Drug Discovery and Development
Background:
- The COVID-19 pandemic necessitates the identification of effective antivirals against SARS-CoV-2.
- Calpain inhibitors have shown promise by targeting the viral main protease (Mpro), crucial for viral polyprotein processing.
Purpose of the Study:
- To investigate the antiviral activity of calpain inhibitors against SARS-CoV-2 through Mpro-independent pathways.
- To identify host factors involved in SARS-CoV-2 entry and their regulation by calpain inhibitors.
- To explore calpain-2 as a potential therapeutic target for COVID-19.
Main Methods:
- Utilized chimeric vesicular stomatitis virus (VSV) encoding the SARS-CoV-2 spike protein.
- Employed genetic knockout of calpain-2 using CRISPR/Cas9 technology.
- Assessed viral infection, cell attachment, and regulation of ACE2 cell surface levels.
Main Results:
- Calpain inhibitors potently inhibited SARS-CoV-2 spike protein-mediated viral entry, independent of Mpro inhibition.
- Genetic knockout of calpain-2 conferred resistance to both chimeric and clinical isolates of SARS-CoV-2.
- Calpain-2 was identified as a key regulator of ACE2 cell surface expression, facilitating viral attachment.
Conclusions:
- Calpain-2 is a novel host factor that positively regulates ACE2 levels, promoting SARS-CoV-2 entry.
- Calpain inhibitors offer a dual-action strategy, inhibiting both viral entry and replication, presenting a promising therapeutic avenue for COVID-19.
- Targeting calpain-2 represents a potential new strategy for combating SARS-CoV-2 infection.
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