Screening and Identification of Lujo Virus Entry Inhibitors From an Food and Drug Administration-Approved Drugs Library.

Junyuan Cao,Gengfu Xiao,Jiao Guo,Minmin Zhou,Yang Liu,Siqi Dong,Ming Tian,Xiaoying Jia,Wei Wang,Yueli Zhang,Yuxia Hou

doi:10.3389/fmicb.2021.793519

Abstract

Lujo virus (LUJV) belongs to the Old World (OW) genus Mammarenavirus (family Arenaviridae). It is categorized as a biosafety level (BSL) 4 agent. Currently, there are no U.S. Food and Drug Administration (FDA)-approved drugs or vaccines specifically for LUJV or other pathogenic OW mammarenaviruses. Here, a high-throughput screening of an FDA-approved drug library was conducted using pseudotype viruses bearing LUJV envelope glycoprotein (GPC) to identify inhibitors of LUJV entry. Three hit compounds, trametinib, manidipine, and lercanidipine, were identified as LUJV entry inhibitors in the micromolar range. Mechanistic studies revealed that trametinib inhibited LUJV GPC-mediated membrane fusion by targeting C410 [located in the transmembrane (TM) domain], while manidipine and lercanidipine inhibited LUJV entry by acting as calcium channel blockers. Meanwhile, all three hits extended their antiviral spectra to the entry of other pathogenic mammarenaviruses. Furthermore, all three could inhibit the authentic prototype mammarenavirus, lymphocytic choriomeningitis virus (LCMV), and could prevent infection at the micromolar level. This study shows that trametinib, manidipine, and lercanidipine are candidates for LUJV therapy and highlights the critical role of calcium in LUJV infection. The presented findings reinforce the notion that the key residue(s) located in the TM domain of GPC provide an entry-targeted platform for designing mammarenavirus inhibitors.

Highlights

Lujo virus (LUJV) was identified in Zambia and South Africa in 2008
For the other Old World (OW) mammarenaviruses that do not possess the corresponding C410, we investigated the viral target by serially passaging LASVrv in the presence of 10 μM trametinib, corresponding to the IC85 value obtained in the LASVpv inhibition assay (Figure 5F)
Trametinib has been shown to play a role as an anti-coronavirus agent that can inhibit the Middle East respiratory syndrome coronavirus infection by modulating the mitogen-activated protein kinase (MAPK)/ERK signaling pathway (Kindrachuk et al, 2015)

Summary

Introduction

Lujo virus (LUJV) was identified in Zambia and South Africa in 2008. It is the pathogen of Lujo hemorrhagic fever (LUHF; Briese et al, 2009). Drugs Against LUJV Entry is sequentially cleaved by signal peptidase and the cellular protease subtilisin kexin isozyme-1/site-1 protease to generate the three subunits of the mature complex: the retained stable signal peptide (SSP), the receptor-binding subunit GP1, and the membrane fusion subunit GP2 (Lenz et al, 2001; Eichler et al, 2003; Igonet et al, 2011; Wang et al, 2016). These three non-covalently bound subunits form a (SSP/GP1/GP2) trimeric complex that is present at the surface of the mature virion. The relatively conserved mammarenavirus SSP and GP2 form an interface that contributes to the stabilization of the prefusion conformation of GPC, and provides an “Achilles’ heel” that can be targeted by the entry inhibitors

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Results

Conclusion