Inhibitors of Deubiquitinating Enzymes Interfere with the SARS-CoV-2 Papain-like Protease and Block Virus Replication
Maximilian Große1, Christian Setz1, Pia Rauch1
1Institute of Virology, Friedrich-Alexander University Erlangen-Nürnberg (FAU), 91054 Erlangen, Germany.
Abstract:
The ubiquitin proteasome system (UPS), particularly its deubiquitinating enzymes (DUBs), play a key role in the replication cycle of coronaviruses. The SARS-CoV-2 papain-like protease (Plpro) is known to process the viral polyproteins to form the replicase transcriptase complex and to counteract the host viral response. Recently, it was shown that this viral protease can also act as a deubiquitinating enzyme. In this study, we demonstrate that certain DUB-Inhibitors (DIs) interfere with SARS-CoV-2 replication. The DIs PR-619 and HBX41108 restrict SARS-CoV-2 in both Vero B4 and human Calu-3 lung cells where cells were infected with a Multiplicity of Infection (MOI) of 0.02. An in vitro protease assay using recombinant Plpro and Amido-4-methylcoumarin (AMC)-conjugated substrate revealed that PR-619 and HBX41108 are able to block the protease at concentrations where the interventions restricted virus replication. In contrast, DIs that do not inhibit Plpro had no influence on virus replication, which indicated that the protease might be at least one major target. Future vertical studies that would gain more insights into the mechanisms of how DUBs effect the replication of SARS-CoV-2 will further validate them as a potential therapeutic target.
Insights
Certain deubiquitinating enzyme inhibitors (DIs) block SARS-CoV-2 replication by inhibiting the viral papain-like protease (Plpro). This finding highlights Plpro as a potential therapeutic target for coronavirus infections.
Area of Science:
- Virology
- Molecular Biology
- Drug Discovery
Background:
- The ubiquitin proteasome system (UPS) and its deubiquitinating enzymes (DUBs) are crucial for coronavirus replication.
- SARS-CoV-2 papain-like protease (Plpro) processes viral polyproteins and modulates host responses, and can also function as a DUB.
Purpose of the Study:
- To investigate the role of DUB-Inhibitors (DIs) in SARS-CoV-2 replication.
- To determine if Plpro is a target for DIs that restrict viral replication.
Main Methods:
- Infection of Vero B4 and Calu-3 cells with SARS-CoV-2 (MOI 0.02).
- Treatment with DIs PR-619 and HBX41108.
- In vitro protease assay using recombinant Plpro and AMC-conjugated substrate.
Main Results:
- PR-619 and HBX41108 significantly restricted SARS-CoV-2 replication in cell cultures.
- These DIs inhibited recombinant Plpro activity at concentrations correlating with antiviral effects.
- DIs lacking Plpro inhibitory activity did not affect viral replication.
Conclusions:
- The SARS-CoV-2 papain-like protease (Plpro) is a key target for DIs that inhibit viral replication.
- DUBs represent a promising therapeutic target for developing novel antiviral strategies against SARS-CoV-2.
