Patch-clamp studies and cell viability assays suggest a distinct site for viroporin inhibitors on the E protein of SARS-CoV-2

Virology Journal

Research

Ulrike Breitinger¹  Hans-Georg Breitinger¹  Christine Adel Sedky¹  Heinrich Sticht² 

[1] Department of Biochemistry, German University in Cairo, Main Entrance of Al Tagamoa Al Khames, 11835, New Cairo, Egypt;Division of Bioinformatics, Institute for Biochemistry, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany;

关键词: SARS-CoV-2;    E protein;    Viroporins;    Cell viability assay;    Patch-clamp electrophysiology;    Viroporin inhibitors;    Ivermectin derivatives;   

DOI  :  10.1186/s12985-023-02095-y

 received in 2022-07-30, accepted in 2023-06-08,  发布年份 2023

来源: Springer

【 摘 要 】

BackgroundSARS-CoV-2 has caused a worldwide pandemic since December 2019 and the search for pharmaceutical targets against COVID-19 remains an important challenge. Here, we studied the envelope protein E of SARS-CoV and SARS-CoV-2, a highly conserved 75–76 amino acid viroporin that is crucial for virus assembly and release. E protein channels were recombinantly expressed in HEK293 cells, a membrane-directing signal peptide ensured transfer to the plasma membrane.MethodsViroporin channel activity of both E proteins was investigated using patch-clamp electrophysiology in combination with a cell viability assay. We verified inhibition by classical viroporin inhibitors amantadine, rimantadine and 5-(N,N-hexamethylene)-amiloride, and tested four ivermectin derivatives.ResultsClassical inhibitors showed potent activity in patch-clamp recordings and viability assays. In contrast, ivermectin and milbemycin inhibited the E channel in patch-clamp recordings but displayed only moderate activity on the E protein in the cell viability assay, which is also sensitive to general cytotoxic activity of the tested compounds. Nemadectin and ivermectin aglycon were inactive. All ivermectin derivatives were cytotoxic at concentrations > 5 µM, i.e. below the level required for E protein inhibition.ConclusionsThis study demonstrates direct inhibition of the SARS-CoV-2 E protein by classical viroporin inhibitors. Ivermectin and milbemycin inhibit the E protein channel but their cytotoxicity argues against clinical application.

【 授权许可】

CC BY   
© The Author(s) 2023

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