Glycopeptide Antibiotics Potently Inhibit Cathepsin L in the Late Endosome/Lysosome and Block the Entry of Ebola Virus, Middle East Respiratory Syndrome Coronavirus (MERS-CoV), and Severe Acute Respiratory Syndrome Coronavirus (SARS-CoV)

Nan Zhou,Ting Pan,Junsong Zhang,Qianwen Li,Xue Zhang,Chuan Bai,Feng Huang,Tao Peng,Jianhua Zhang,Chao Liu,Liang Tao,Hui Zhang

doi:10.1074/jbc.m116.716100

Abstract

Ebola virus infection can cause severe hemorrhagic fever with a high mortality in humans. The outbreaks of Ebola viruses in 2014 represented the most serious Ebola epidemics in history and greatly threatened public health worldwide. The development of additional effective anti-Ebola therapeutic agents is therefore quite urgent. In this study, via high throughput screening of Food and Drug Administration-approved drugs, we identified that teicoplanin, a glycopeptide antibiotic, potently prevents the entry of Ebola envelope pseudotyped viruses into the cytoplasm. Furthermore, teicoplanin also has an inhibitory effect on transcription- and replication-competent virus-like particles, with an IC50 as low as 330 nm. Comparative analysis further demonstrated that teicoplanin is able to block the entry of Middle East respiratory syndrome (MERS) and severe acute respiratory syndrome (SARS) envelope pseudotyped viruses as well. Teicoplanin derivatives such as dalbavancin, oritavancin, and telavancin can also inhibit the entry of Ebola, MERS, and SARS viruses. Mechanistic studies showed that teicoplanin blocks Ebola virus entry by specifically inhibiting the activity of cathepsin L, opening a novel avenue for the development of additional glycopeptides as potential inhibitors of cathepsin L-dependent viruses. Notably, given that teicoplanin has routinely been used in the clinic with low toxicity, our work provides a promising prospect for the prophylaxis and treatment of Ebola, MERS, and SARS virus infection.

Highlights

The Ebola virus genome contains seven genes that encode the NP, VP35, VP40, glycoprotein (GP), VP30, VP24, and RNAdependent RNA polymerase (L) virus proteins
To exclude the hits that only inhibited early events of the HIV-1 life cycle and to identify Ebola virus (EBOV)-GP-specific drugs, HIV-luc/ VSV-G pseudotyped viruses bearing vesicular stomatitis virus (VSV) glycoproteins were used for secondary screening of the initial hit compounds
Teicoplanin Has No Effect on HOPS Complexes—We further examined the host factors that are required for both Ebola viruses and severe acute respiratory syndrome (SARS)-CoVs but not VSVs using siRNAs

Summary

Experimental Procedures

Cell Culture—HEK293T, A549, HeLa, Huh7.5.1, and MadinDarby canine kidney cell lines were maintained in Dulbecco’s modified Eagle’s medium (Gibco) with 10% fetal calf serum (Gibco), 100 units/ml penicillin, and 100 ␮g/ml streptomycin (Gibco) at 37 °C and 5% CO2. HEK293T cells were incubated with compounds at 37 °C for 1 h and infected with 100 ␮l of p24-normalized (5 ng) HIV-luc/Zaire EBOV-GP (2014) pseudotyped viruses containing 10 ␮g/ml Polybrene. The cells were infected with HIV-luc/Zaire EBOV-GP (2014) pseudotyped viruses and incubated with 50 ␮M teicoplanin at 0, 2, 4, or 8 h post-infection. After 24 h, the cells were incubated with teicoplanin at various concentrations at 37 °C for 1 h and infected with p24-normalized (100 ng) HIVluc/Zaire EBOV-GP (2014) or HIV-luc/VSV-G pseudotyped viruses per well. After 6 h, the cells were washed twice with PBS and incubated with 0.25% trypsin at 37 °C for 2 min to remove the viruses that adhered to the cell surfaces.

Clinically approved drugs screened

Results

Teicoplanin Dalbavancin Oritavancin Telavancin Vancomycin CTSL inhibitor

Discussion