Posaconazole inhibits multiple steps of the alphavirus replication cycle

Finny S Varghese,Febrina Meutiawati,Mona Teppor,Sofie Jacobs,Carolien De Keyzer,Ezgi Taşköprü,Esther Van Woudenbergh,Gijs J Overheul,Ellen Bouma,Jolanda M Smit,Leen Delang,Andres Merits,Ronald P Van Rij

doi:10.1016/j.antiviral.2021.105223

Abstract

Repurposing drugs is a promising strategy to identify therapeutic interventions against novel and re-emerging viruses. Posaconazole is an antifungal drug used to treat invasive aspergillosis and candidiasis. Recently, posaconazole and its structural analog, itraconazole were shown to inhibit replication of multiple viruses by modifying intracellular cholesterol homeostasis. Here, we show that posaconazole inhibits replication of the alphaviruses Semliki Forest virus (SFV), Sindbis virus and chikungunya virus with EC50 values ranging from 1.4 μM to 9.5 μM. Posaconazole treatment led to a significant reduction of virus entry in an assay using a temperature-sensitive SFV mutant, but time-of-addition and RNA transfection assays indicated that posaconazole also inhibits post-entry stages of the viral replication cycle. Virus replication in the presence of posaconazole was partially rescued by the addition of exogenous cholesterol. A transferrin uptake assay revealed that posaconazole considerably slowed down cellular endocytosis. A single point mutation in the SFV E2 glycoprotein, H255R, provided partial resistance to posaconazole as well as to methyl-β-cyclodextrin, corroborating the effect of posaconazole on cholesterol and viral entry. Our results indicate that posaconazole inhibits multiple steps of the alphavirus replication cycle and broaden the spectrum of viruses that can be targeted in vitro by posaconazole, which could be further explored as a therapeutic agent against emerging viruses.

Highlights

Due to their diversity and proclivity to mutate, emerging and reemerging viruses have the potential to cause large-scale morbidity and mortality
We show that PCZ has potent antiviral activity against multiple alphaviruses including Chikungunya virus (CHIKV), Semliki Forest virus (SFV) and Sindbis virus (SINV)
To test the specificity of PCZ, we tested the compound against other Nano luciferase (Nluc) reporter alphaviruses, Sindbis virus (SINV) and CHIKV, and found that they were susceptible to PCZ (EC50 = 3.2 and 1.4 μM, respectively) (Supplementary Figs. 1B and S1C, Table 1)

Summary

Introduction

Due to their diversity and proclivity to mutate, emerging and reemerging viruses have the potential to cause large-scale morbidity and mortality. A licensed vaccine or specific antiviral therapy is lacking and for those viruses for which antiviral drugs are available, high mutational rates and incomplete drug adherence may result in the emergence of drug resistance (Woolhouse et al, 2013; Carrasco-Hernandez et al, 2017). It is of utmost importance to continue the search for effective, broadly active antiviral compounds. Of special interest in this regard is drug repurposing (Mercorelli et al, 2018). The costs for the development of a new drug are estimated at approximately $2.6 billion. Repurposing a clinically approved drug for a new indication could considerably shorten the developmental timeline

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Conclusion