scholarly journals Identification of a Broad-Spectrum Arenavirus Entry Inhibitor

2008 ◽  
Vol 82 (21) ◽  
pp. 10768-10775 ◽  
Author(s):  
Ryan A. Larson ◽  
Dongcheng Dai ◽  
Virginia T. Hosack ◽  
Ying Tan ◽  
Tove’ C. Bolken ◽  
...  
Keyword(s):  
Antiviral Activity ◽  
Viral Entry ◽  
Transmembrane Domain ◽  
Benzimidazole Derivative ◽  
Genetic Selection ◽  
Hemorrhagic Fever ◽  
Lymphocytic Choriomeningitis ◽  
Site Directed Mutagenesis ◽  
Lassa Virus ◽  
Carboxy Terminal

ABSTRACT Several arenaviruses, including Lassa virus (LASV), are causative agents of hemorrhagic fever, for which effective therapeutic options are lacking. The LASV envelope glycoprotein (GP) gene was used to generate lentiviral pseudotypes to identify small-molecule inhibitors of viral entry. A benzimidazole derivative with potent antiviral activity was identified from a high-throughput screen utilizing this strategy. Subsequent lead optimization for antiviral activity identified a modified structure, ST-193, with a 50% inhibitory concentration (IC50) of 1.6 nM against LASV pseudotypes. ST-193 inhibited pseudotypes generated with other arenavirus envelopes as well, including the remaining four commonly associated with hemorrhagic fever (IC50s for Junín, Machupo, Guanarito, and Sabiá were in the 0.2 to 12 nM range) but exhibited no antiviral activity against pseudotypes incorporating either the GP from the LASV-related arenavirus lymphocytic choriomeningitis virus (LCMV) or the unrelated G protein from vesicular stomatitis virus, at concentrations of up to 10 μM. Determinants of ST-193 sensitivity were mapped through a combination of LASV-LCMV domain-swapping experiments, genetic selection of viral variants, and site-directed mutagenesis. Taken together, these studies demonstrate that sensitivity to ST-193 is dictated by a segment of about 30 amino acids within the GP2 subunit. This region includes the carboxy-terminal region of the ectodomain and the predicted transmembrane domain of the envelope protein, revealing a novel antiviral target within the arenavirus envelope GP.

scholarly journals Lassa Virus Cell Entry via Dystroglycan Involves an Unusual Pathway of Macropinocytosis

2016 ◽  
Vol 90 (14) ◽  
pp. 6412-6429 ◽  
Author(s):  
Joel Oppliger ◽  
Giulia Torriani ◽  
Antonio Herrador ◽  
Stefan Kunz
Keyword(s):  
Antiviral Activity ◽  
Host Cell ◽  
Therapeutic Intervention ◽  
Kinase Inhibitors ◽  
Hemorrhagic Fever ◽  
Human Cells ◽  
New Drugs ◽  
High Rate ◽  
Actin Dynamics ◽  
Lassa Virus

ABSTRACTThe pathogenic Old World arenavirus Lassa virus (LASV) causes a severe hemorrhagic fever with a high rate of mortality in humans. Several LASV receptors, including dystroglycan (DG), TAM receptor tyrosine kinases, and C-type lectins, have been identified, suggesting complex receptor use. Upon receptor binding, LASV enters the host cell via an unknown clathrin- and dynamin-independent pathway that delivers the virus to late endosomes, where fusion occurs. Here we investigated the mechanisms underlying LASV endocytosis in human cells in the context of productive arenavirus infection, using recombinant lymphocytic choriomeningitis virus (rLCMV) expressing the LASV glycoprotein (rLCMV-LASVGP). We found that rLCMV-LASVGP entered human epithelial cells via DG using a macropinocytosis-related pathway independently of alternative receptors. Dystroglycan-mediated entry of rLCMV-LASVGP required sodium hydrogen exchangers, actin, and the GTPase Cdc42 and its downstream targets, p21-activating kinase-1 (PAK1) and Wiskott-Aldrich syndrome protein (N-Wasp). Unlike other viruses that enter cells via macropinocytosis, rLCMV-LASVGP entry did not induce overt changes in cellular morphology and hardly affected actin dynamics or fluid uptake. Screening of kinase inhibitors identified protein kinase C, phosphoinositide 3-kinase, and the receptor tyrosine kinase human hepatocyte growth factor receptor (HGFR) to be regulators of rLCMV-LASVGP entry. The HGFR inhibitor EMD 1214063, a candidate anticancer drug, showed antiviral activity against rLCMV-LASVGP at the level of entry. When combined with ribavirin, which is currently used to treat human arenavirus infection, EMD 1214063 showed additive antiviral effects. In sum, our study reveals that DG can link LASV to an unusual pathway of macropinocytosis that causes only minimal perturbation of the host cell and identifies cellular kinases to be possible novel targets for therapeutic intervention.IMPORTANCELassa virus (LASV) causes several hundred thousand infections per year in Western Africa, with the mortality rate among hospitalized patients being high. The current lack of a vaccine and the limited therapeutic options at hand make the development of new drugs against LASV a high priority. In the present study, we uncover that LASV entry into human cells via its major receptor, dystroglycan, involves an unusual pathway of macropinocytosis and define a set of cellular factors implicated in the regulation of LASV entry. A screen of kinase inhibitors revealed HGFR to be a possible candidate target for antiviral drugs against LASV. An HGFR candidate inhibitor currently being evaluated for cancer treatment showed potent antiviral activity and additive drug effects with ribavirin, which is used in the clinic to treat human LASV infection. In sum, our study reveals novel fundamental aspects of the LASV-host cell interaction and highlights a possible candidate drug target for therapeutic intervention.

scholarly journals Inhibition of arenavirus entry and replication by the cell-intrinsic restriction factor ZMPSTE24 is enhanced by IFITM antiviral activity

2021 ◽  
Author(s):  
Robert J Stott ◽  
Toshana L Foster
Keyword(s):  
Virus Infection ◽  
Antiviral Activity ◽  
Viral Entry ◽  
Transmembrane Protein ◽  
Membrane Integrity ◽  
A549 Cells ◽  
Cellular Membrane ◽  
Restriction Factor ◽  
Lassa Virus ◽  
Live Virus

In the absence of effective vaccines and treatments, annual outbreaks of severe human haemorrhagic fever caused by arenaviruses, such as Lassa virus, continue to pose a significant human health threat. Understanding the balance of cellular factors that inhibit or promote arenavirus infection may have important implications for the development of effective antiviral strategies. Here, we identified the cell-intrinsic zinc transmembrane metalloprotease, ZMPSTE24, as a restriction factor against arenaviruses. Notably, CRISPR-Cas9-mediated knockout of ZMPSTE24 in human alveolar epithelial A549 cells increased arenavirus glycoprotein-mediated viral entry in pseudoparticle assays and live virus infection models. As a barrier to viral entry and replication, ZMPSTE24 may act as a downstream effector of interferon-induced transmembrane protein (IFITM) antiviral function; though through a yet poorly understood mechanism. Overexpression of IFITM1, IFITM2 and IFITM3 proteins did not restrict the entry of pseudoparticles carrying arenavirus envelope glycoproteins and live virus infection, yet depletion of IFITM protein expression enhanced virus entry and replication. Furthermore, gain-of-function studies revealed that IFITMs augment the antiviral activity of ZMPSTE24 against arenaviruses, suggesting a cooperative effect of viral restriction. We show that ZMPSTE24 and IFITMs affect the kinetics of cellular endocytosis, suggesting that perturbation of membrane structure and stability is likely the mechanism of ZMPSTE24-mediated restriction and cooperative ZMPSTE24-IFITM antiviral activity. Collectively, our findings define the role of ZMPSTE24 host restriction activity in the early stages of arenavirus infection. Moreover, we provide insight into the importance of cellular membrane integrity for productive fusion of arenaviruses and highlight a novel avenue for therapeutic development.

scholarly journals Screening of Botanical Drugs against Lassa Virus Entry

2021 ◽  
Author(s):  
Yang Liu ◽  
Jiao Guo ◽  
Junyuan Cao ◽  
Guangshun Zhang ◽  
Xiaoying Jia ◽  
...  
Keyword(s):  
Membrane Fusion ◽  
High Throughput Screening ◽  
Transmembrane Domain ◽  
Lassa Fever ◽  
Lymphocytic Choriomeningitis ◽  
Mechanistic Study ◽  
Lassa Virus ◽  
Potential Candidate ◽  
Botanical Drug ◽  
Approved Drugs

Lassa virus (LASV) belongs to the Old World Mammarenavirus genus (family Arenaviridae). At present, there are no approved drugs or vaccines specific for LASV. In this study, high-throughput screening of a botanical drug library was performed against LASV entry using a pseudotype virus bearing the LASV envelope glycoprotein complex (GPC). Two hit compounds, bergamottin and casticin, were identified as micromolar range inhibitors of LASV entry. A mechanistic study revealed that casticin inhibited LASV entry by blocking low pH-induced membrane fusion. Analysis of adaptive mutants demonstrated that the F446L mutation, located in the transmembrane domain of GP2, conferred resistance to casticin. Furthermore, casticin antiviral activity extends to the New World (NW) pathogenic mammarenaviruses, and mutation of the conserved F446 also conferred resistance to casticin in these viruses. Unlike casticin, bergamottin showed little effect on LASV GPC-mediated membrane fusion, instead inhibiting LASV entry by blocking endocytic trafficking. Notably, both compounds showed inhibitory effects on authentic lymphocytic choriomeningitis virus. Our study shows that both casticin and bergamottin are candidates for LASV therapy and that the conserved F446 in LASV GPC is important in drug resistance in mammarenaviruses. IMPORTANCE: Currently, there is no approved therapy to treat Lassa fever (LASF). Our goal was to identify potential candidate molecules for LASF therapy. Herein, we screened a botanical drug library and identified two compounds, casticin and bergamottin, that inhibited LASV entry via different mechanisms.

scholarly journals T-705 (Favipiravir) Inhibition of Arenavirus Replication in Cell Culture

2010 ◽  
Vol 55 (2) ◽  
pp. 782-787 ◽  
Author(s):  
Michelle Mendenhall ◽  
Andrew Russell ◽  
Terry Juelich ◽  
Emily L. Messina ◽  
Donald F. Smee ◽  
...  
Keyword(s):  
Cell Culture ◽  
Antiviral Activity ◽  
Viral Replication ◽  
Antiviral Agent ◽  
Febrile Illness ◽  
Hemorrhagic Fever ◽  
Intermediate Stage ◽  
Lymphocytic Choriomeningitis ◽  
Hamster Model ◽  
Highly Pathogenic

ABSTRACTA number of New World arenaviruses (Junín [JUNV], Machupo [MACV], and Guanarito [GTOV] viruses) can cause human disease ranging from mild febrile illness to a severe and often fatal hemorrhagic fever syndrome. These highly pathogenic viruses and the Old World Lassa fever virus pose a significant threat to public health and national security. The only licensed antiviral agent with activity against these viruses, ribavirin, has had mixed success in treating severe arenaviral disease and is associated with significant toxicities. A novel pyrazine derivative currently in clinical trials for the treatment of influenza virus infections, T-705 (favipiravir), has demonstrated broad-spectrum activity against a number of RNA viruses, including arenaviruses. T-705 has also been shown to be effective against Pichinde arenavirus infection in a hamster model. Here, we demonstrate the robust antiviral activity of T-705 against authentic highly pathogenic arenaviruses in cell culture. We show that T-705 disrupts an early or intermediate stage in viral replication, distinct from absorption or release, and that its antiviral activity in cell culture is reversed by the addition of purine bases and nucleosides, but not with pyrimidines. Specific inhibition of viral replication/transcription by T-705 was demonstrated using a lymphocytic choriomeningitis arenavirus replicon system. Our findings indicate that T-705 acts to inhibit arenavirus replication/transcription and may directly target the viral RNA-dependent RNA polymerase.

scholarly journals The Janus Kinase Inhibitor Ruxolitinib Prevents Terminal Shock in a Mouse Model of Arenavirus Hemorrhagic Fever

2021 ◽  
Vol 9 (3) ◽  
pp. 564
Author(s):  
Mehmet Sahin ◽  
Melissa M. Remy ◽  
Doron Merkler ◽  
Daniel D. Pinschewer
Keyword(s):  
Kinase Inhibitor ◽  
Antibody Therapy ◽  
Hemorrhagic Fever ◽  
Lassa Fever ◽  
Lymphocytic Choriomeningitis ◽  
Janus Kinase ◽  
Lassa Virus ◽  
Jak Inhibitor ◽  
Medical Needs ◽  
Ifn Γ

Arenaviruses such as Lassa virus cause arenavirus hemorrhagic fever (AVHF), but protective vaccines and effective antiviral therapy remain unmet medical needs. Our prior work has revealed that inducible nitric oxide synthase (iNOS) induction by IFN-γ represents a key pathway to microvascular leak and terminal shock in AVHF. Here we hypothesized that Ruxolitinib, an FDA-approved JAK inhibitor known to prevent IFN-γ signaling, could be repurposed for host-directed therapy in AVHF. We tested the efficacy of Ruxolitinib in MHC-humanized (HHD) mice, which develop Lassa fever-like disease upon infection with the monkey-pathogenic lymphocytic choriomeningitis virus strain WE. Anti-TNF antibody therapy was tested as an alternative strategy owing to its expected effect on macrophage activation. Ruxolitinib but not anti-TNF antibody prevented hypothermia and terminal disease as well as pleural effusions and skin edema, which served as readouts of microvascular leak. As expected, neither treatment influenced viral loads. Intriguingly, however, and despite its potent disease-modifying activity, Ruxolitinib did not measurably interfere with iNOS expression or systemic NO metabolite levels. These findings suggest that the FDA-approved JAK-inhibitor Ruxolitinib has potential in the treatment of AVHF. Moreover, our observations indicate that besides IFN-γ-induced iNOS additional druggable pathways contribute essentially to AVHF and are amenable to host-directed therapy.

scholarly journals Identification of residues in Lassa virus glycoprotein 1 involved in receptor switch

2021 ◽  
Author(s):  
Jiao Guo ◽  
Xiaoying Jia ◽  
Yang Liu ◽  
Junyuan Cao ◽  
Gengfu Xiao ◽  
...  
Keyword(s):  
Binding Affinity ◽  
Rna Virus ◽  
Treatment Options ◽  
Hemorrhagic Fever ◽  
Cell Types ◽  
Lymphocytic Choriomeningitis ◽  
Lassa Virus ◽  
Viral Glycoprotein ◽  
Mutant Proteins ◽  
Alpha Dystroglycan

Lassa virus (LASV) is an enveloped, negative-sense RNA virus that causes Lassa hemorrhagic fever, for which there are limited treatment options. Successful LASV entry requires the viral glycoprotein 1 (GP1) to undergo a receptor switch from its primary receptor alpha-dystroglycan (α-DG) to its endosomal receptor lysosome-associated membrane protein 1 (LAMP1). A conserved histidine triad in LASV GP1 has been reported to be responsible for receptor switch. To test the hypothesis that other non-conserved residues also contribute to receptor switch, we constructed a series of GP1 mutant proteins and tested them for binding to LAMP1. Four residues, L84, K88, L107, and H170, were identified as critical for receptor switch. Substituting any of the four residues with the corresponding lymphocytic choriomeningitis virus residue (L84N, K88E, L10F, and H170S) reduced the binding affinity of GP1LASV for LAMP1. Moreover, all the mutations caused decreases in GPC-mediated membrane fusion at both pH 4.5 and 5.2. The infectivity of pseudotyped viruses bearing either GPCL84N or GPCK88E decreased sharply in multiple cell types, whereas L107F and H170S had only mild effects on infectivity. Notably, in LAMP1 knockout cells, all four mutants showed reduced pseudovirus infectivity. Using biolayer light interferometry assay, we found that all four mutants had decreased binding affinity to LAMP1, in the order L84N > L107F > K88E > H170S.

scholarly journals Screening of FDA-approved Drugs and Identification of Novel Lassa Virus Entry Inhibitors

2018 ◽  
Author(s):  
Peilin Wang ◽  
Yang Liu ◽  
Guangshun Zhang ◽  
Shaobo Wang ◽  
Jiao Guo ◽  
...  
Keyword(s):  
High Throughput Screening ◽  
Transmembrane Domain ◽  
Hemorrhagic Fever ◽  
Mechanistic Study ◽  
Lassa Virus ◽  
Entry Inhibitors ◽  
Glycoprotein Complex ◽  
Virus Entry Inhibitors ◽  
Approved Drugs ◽  
Fda Approved Drugs

ABSTRACTLassa virus (LASV) belongs to the Mammarenavirus genus (family Arenaviridae) and causes severe hemorrhagic fever in humans. At present, there are no Food and Drug Administration (FDA)-approved drugs or vaccines specific for LASV. Herein, high-throughput screening of an FDA-approved drug library was performed against LASV entry using a pseudo-type virus enveloping LASV glycoproteins. Two hit drugs, lacidipine and phenothrin, were identified as LASV entry inhibitors in the micromolar range. A mechanistic study revealed that both drugs inhibited LASV entry by blocking low-pH-induced membrane fusion. Moreover, lacidipine irreversibly bound to the LASV glycoprotein complex (GPC), resulting in virucidal activity. Adaptive mutant analyses demonstrated that replacement of T40, located in the ectodomain of the stable-signal peptide (SSP), with lysine (K) conferred LASV resistance to lacidipine without apparent loss of the viral growth profile. Furthermore, lacidipine showed antiviral activity and specificity against both LASV and the Guanarito virus (GTOV), which is also a category A new world arenavirus. Drug-resistant variants indicate that the V36M in ectodomain of SSP mutant and V436A in the transmembrane domain of GP2 mutant conferred GTOV resistance to lacidipine, suggesting that lacidipine might act via a novel mechanism other than calcium inhibition. This study shows that both lacidipine and phenothrin are candidates for LASV therapy, and the membrane-proximal external region of the GPC might provide an entry-targeted platform for inhibitors.

scholarly journals Identification and Mechanism of Action of a Novel Small-Molecule Inhibitor of Arenavirus Multiplication

2015 ◽  
Vol 89 (21) ◽  
pp. 10924-10933 ◽  
Author(s):  
Nhi Ngo ◽  
Beatrice Cubitt ◽  
Masaharu Iwasaki ◽  
Juan C. de la Torre
Keyword(s):  
Mechanism Of Action ◽  
Transmembrane Domain ◽  
Unmet Need ◽  
Hemorrhagic Fever ◽  
Lymphocytic Choriomeningitis ◽  
Lymphocytic Choriomeningitis Virus ◽  
High Morbidity ◽  
Human Pathogen ◽  
Human Pathogens ◽  
A Cell

ABSTRACTSeveral arenaviruses cause hemorrhagic fever disease in humans and represent important public health problems in the regions where these viruses are endemic. In addition, evidence indicates that the worldwide-distributed prototypic arenavirus lymphocytic choriomeningitis virus (LCMV) is an important neglected human pathogen. There are no licensed arenavirus vaccines and current antiarenavirus therapy is limited to the use of ribavirin that is only partially effective. Therefore, there is an unmet need for novel antiarenaviral therapeutics. Here, we report the generation of a novel recombinant LCM virus and its use to develop a cell-based high-throughput screen to rapidly identify inhibitors of LCMV multiplication. We used this novel assay to screen a library of 30,400 small molecules and identified compound F3406 (chemical name:N-[3,5-bis(fluoranyl)phenyl]-2-[5,7-bis(oxidanylidene)-6-propyl-2-pyrrolidin-1-yl-[1,3]thiazolo[4,5-d]pyrimidin-4-yl]ethanamide), which exhibited strong anti-LCMV activity in the absence of cell toxicity. Mechanism-of-action studies revealed that F3406 inhibited LCMV cell entry by specifically interfering with the pH-dependent fusion in the endosome compartment that is mediated by LCMV glycoprotein GP2 and required to release the virus ribonucleoprotein into the cell cytoplasm to initiate transcription and replication of the virus genome. We identified residue M437 within the transmembrane domain of GP2 as critical for virus susceptibility to F3406.IMPORTANCEHemorrhagic fever arenaviruses (HFA) are important human pathogens that cause high morbidity and mortality in areas where these viruses are endemic. In addition, evidence indicates that the worldwide-distributed prototypic arenavirus lymphocytic choriomeningitis virus (LCMV) is a neglected human pathogen of clinical significance. Concerns posed by arenavirus infections are aggravated by the lack of U.S. Food and Drug Administration-licensed arenavirus vaccines and current antiarenaviral therapy being limited to the off-label use of ribavirin that is only partially effective. Here we describe a novel recombinant LCMV and its use to develop a cell-based assay suitable for HTS to rapidly identify inhibitors arenavirus multiplication. The concepts and experimental strategies we describe in this work provide the bases for the rapid identification and characterization of novel anti-HFA therapeutics.

scholarly journals E3 Ligase ITCH Interacts with the Z Matrix Protein of Lassa and Mopeia Viruses and Is Required for the Release of Infectious Particles

Viruses ◽  
2019 ◽  
Vol 12 (1) ◽  
pp. 49 ◽  
Author(s):  
Nicolas Baillet ◽  
Sophie Krieger ◽  
Xavier Carnec ◽  
Mathieu Mateo ◽  
Alexandra Journeaux ◽  
...  
Keyword(s):  
Ubiquitin Ligase ◽  
Matrix Protein ◽  
Virus Assembly ◽  
Hemorrhagic Fever ◽  
Lassa Fever ◽  
Lymphocytic Choriomeningitis ◽  
Lassa Virus ◽  
Yeast Two Hybrid ◽  
Ubiquitin Ligase Activity ◽  
Two Hybrid

Lassa virus (LASV) and Mopeia virus (MOPV) are two closely related, rodent-born mammarenaviruses. LASV is the causative agent of Lassa fever, a deadly hemorrhagic fever endemic in West Africa, whereas MOPV is non-pathogenic in humans. The Z matrix protein of arenaviruses is essential to virus assembly and budding by recruiting host factors, a mechanism that remains partially defined. To better characterize the interactions involved, a yeast two-hybrid screen was conducted using the Z proteins from LASV and MOPV as a bait. The cellular proteins ITCH and WWP1, two members of the Nedd4 family of HECT E3 ubiquitin ligases, were found to bind the Z proteins of LASV, MOPV and other arenaviruses. The PPxY late-domain motif of the Z proteins is required for the interaction with ITCH, although the E3 ubiquitin-ligase activity of ITCH is not involved in Z ubiquitination. The silencing of ITCH was shown to affect the replication of the old-world mammarenaviruses LASV, MOPV, Lymphocytic choriomeningitis virus (LCMV) and to a lesser extent Lujo virus (LUJV). More precisely, ITCH was involved in the egress of virus-like particles and the release of infectious progeny viruses. Thus, ITCH constitutes a novel interactor of LASV and MOPV Z proteins that is involved in virus assembly and release.

scholarly journals Inhibition of Ebola Virus Entry by a C-peptide Targeted to Endosomes

2011 ◽  
Vol 286 (18) ◽  
pp. 15854-15861 ◽  
Author(s):  
Emily Happy Miller ◽  
Joseph S. Harrison ◽  
Sheli R. Radoshitzky ◽  
Chelsea D. Higgins ◽  
Xiaoli Chi ◽  
...  
Keyword(s):  
Antiviral Activity ◽  
Viral Entry ◽  
Ebola Virus ◽  
Hemorrhagic Fever ◽  
Marburg Virus ◽  
Viral Envelope ◽  
Heptad Repeat ◽  
Fusion Event ◽  
C Peptide ◽  
Hiv 1

Ebola virus (EboV) and Marburg virus (MarV) (filoviruses) are the causative agents of severe hemorrhagic fever. Infection begins with uptake of particles into cellular endosomes, where the viral envelope glycoprotein (GP) catalyzes fusion between the viral and host cell membranes. This fusion event is thought to involve conformational rearrangements of the transmembrane subunit (GP2) of the envelope spike that ultimately result in formation of a six-helix bundle by the N- and C-terminal heptad repeat (NHR and CHR, respectively) regions of GP2. Infection by other viruses employing similar viral entry mechanisms (such as HIV-1 and severe acute respiratory syndrome coronavirus) can be inhibited with synthetic peptides corresponding to the native CHR sequence (“C-peptides”). However, previously reported EboV C-peptides have shown weak or insignificant antiviral activity. To determine whether the activity of a C-peptide could be improved by increasing its intracellular concentration, we prepared an EboV C-peptide conjugated to the arginine-rich sequence from HIV-1 Tat, which is known to accumulate in endosomes. We found that this peptide specifically inhibited viral entry mediated by filovirus GP proteins and infection by authentic filoviruses. We determined that antiviral activity was dependent on both the Tat sequence and the native EboV CHR sequence. Mechanistic studies suggested that the peptide acts by blocking a membrane fusion intermediate.

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