Autophagy Promotes Infectious Particle Production of Mopeia and Lassa Viruses

Lassa virus (LASV) and Mopeia virus (MOPV) are two closely related Old-World mammarenaviruses. LASV causes severe hemorrhagic fever with high mortality in humans, whereas no case of MOPV infection has been reported. Comparing MOPV and LASV is a powerful strategy to unravel pathogenic mechanisms that occur during the course of pathogenic arenavirus infection. We used a yeast two-hybrid approach to identify cell partners of MOPV and LASV Z matrix protein in which two autophagy adaptors were identified, NDP52 and TAX1BP1. Autophagy has emerged as an important cellular defense mechanism against viral infections but its role during arenavirus infection has not been shown. Here, we demonstrate that autophagy is transiently induced by MOPV, but not LASV, in infected cells two days after infection. Impairment of the early steps of autophagy significantly decreased the production of MOPV and LASV infectious particles, whereas a blockade of the degradative steps impaired only MOPV infectious particle production. Our study provides insights into the role played by autophagy during MOPV and LASV infection and suggests that this process could partially explain their different pathogenicity.

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Lassa Virus Vaccine Candidate ML29 Generates Truncated Viral RNAs Which Contribute to Interfering Activity and Attenuation

Viruses ◽

10.3390/v13020214 ◽

2021 ◽

Vol 13 (2) ◽

pp. 214

Author(s):

Dylan M. Johnson ◽

Beatrice Cubitt ◽

Tia L. Pfeffer ◽

Juan Carlos de la Torre ◽

Igor S. Lukashevich

Keyword(s):

Matrix Protein ◽

Fluorescent Protein ◽

Vaccine Candidate ◽

Small Animal ◽

Lymphocytic Choriomeningitis ◽

Lassa Virus ◽

Defective Interfering Particles ◽

Persistently Infected ◽

Viral Genomes ◽

Infected Cells

Defective interfering particles (DIPs) are naturally occurring products during virus replication in infected cells. DIPs contain defective viral genomes (DVGs) and interfere with replication and propagation of their corresponding standard viral genomes by competing for viral and cellular resources, as well as promoting innate immune antiviral responses. Consequently, for many different viruses, including mammarenaviruses, DIPs play key roles in the outcome of infection. Due to their ability to broadly interfere with viral replication, DIPs are attractive tools for the development of a new generation of biologics to target genetically diverse and rapidly evolving viruses. Here, we provide evidence that in cells infected with the Lassa fever (LF) vaccine candidate ML29, a reassortant that carries the nucleoprotein (NP) and glycoprotein (GP) dominant antigens of the pathogenic Lassa virus (LASV) together with the L polymerase and Z matrix protein of the non-pathogenic genetically related Mopeia virus (MOPV), L-derived truncated RNA species are readily detected following infection at low multiplicity of infection (MOI) or in persistently-infected cells originally infected at high MOI. In the present study, we show that expression of green fluorescent protein (GFP) driven by a tri-segmented form of the mammarenavirus lymphocytic choriomeningitis virus (r3LCMV-GFP/GFP) was strongly inhibited in ML29-persistently infected cells, and that the magnitude of GFP suppression was dependent on the passage history of the ML29-persistently infected cells. In addition, we found that DIP-enriched ML29 was highly attenuated in immunocompetent CBA/J mice and in Hartley guinea pigs. Likewise, STAT-1-/- mice, a validated small animal model for human LF associated hearing loss sequelae, infected with DIP-enriched ML29 did not exhibit any hearing abnormalities throughout the observation period (62 days).

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Crystal Structure of the Oligomeric Form of Lassa Virus Matrix Protein Z

Journal of Virology ◽

10.1128/jvi.02896-15 ◽

2016 ◽

Vol 90 (9) ◽

pp. 4556-4562 ◽

Cited By ~ 14

Author(s):

Kathryn M. Hastie ◽

Michelle Zandonatti ◽

Tong Liu ◽

Sheng Li ◽

Virgil L. Woods ◽

...

Keyword(s):

Crystal Structure ◽

Life Cycle ◽

Matrix Protein ◽

Hemorrhagic Fever ◽

Viral Life Cycle ◽

Lassa Virus ◽

Protein Z ◽

Basic Center ◽

Oligomeric Form ◽

Oligomeric Forms

ABSTRACTThe arenavirus matrix protein Z is highly multifunctional and occurs in both monomeric and oligomeric forms. The crystal structure of a dodecamer of Z from Lassa virus, presented here, illustrates a ring-like structure with a highly basic center. Mutagenesis demonstrates that the dimeric interface within the dodecamer and a Lys-Trp-Lys triad at the center of the ring are important for oligomerization. This structure provides an additional template to explore the many functions of Z.IMPORTANCEThe arenavirus Lassa virus causes hundreds of thousands of infections each year, many of which develop into fatal hemorrhagic fever. The arenavirus matrix protein Z is multifunctional, with at least four distinct roles. Z exists in both monomeric and oligomeric forms, each of which likely serves a specific function in the viral life cycle. Here we present the dodecameric form of Lassa virus Z and demonstrate that Z forms a “wreath” with a highly basic center. This structure and that of monomeric Z now provide a pair of critical templates by which the multiple roles of Z in the viral life cycle may be interpreted.

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

Viruses ◽

10.3390/v12010049 ◽

2019 ◽

Vol 12 (1) ◽

pp. 49 ◽

Cited By ~ 2

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.

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Oncogenic Effects of HIV-1 Proteins, Mechanisms Behind

Cancers ◽

10.3390/cancers13020305 ◽

2021 ◽

Vol 13 (2) ◽

pp. 305

Author(s):

Maria Isaguliants ◽

Ekaterina Bayurova ◽

Darya Avdoshina ◽

Alla Kondrashova ◽

Francesca Chiodi ◽

...

Keyword(s):

Matrix Protein ◽

Viral Infections ◽

Kaposi Sarcoma ◽

Successful Implementation ◽

Non Hodgkin Lymphoma ◽

Increased Risk ◽

Carcinogenic Effects ◽

Infected Cells ◽

Transactivator Of Transcription ◽

Hiv 1

People living with human immunodeficiency virus (HIV-1) are at increased risk of developing cancer, such as Kaposi sarcoma (KS), non-Hodgkin lymphoma (NHL), cervical cancer, and other cancers associated with chronic viral infections. Traditionally, this is linked to HIV-1-induced immune suppression with depletion of CD4+ T-helper cells, exhaustion of lymphopoiesis and lymphocyte dysfunction. However, the long-term successful implementation of antiretroviral therapy (ART) with an early start did not preclude the oncological complications, implying that HIV-1 and its antigens are directly involved in carcinogenesis and may exert their effects on the background of restored immune system even when present at extremely low levels. Experimental data indicate that HIV-1 virions and single viral antigens can enter a wide variety of cells, including epithelial. This review is focused on the effects of five viral proteins: envelope protein gp120, accessory protein negative factor Nef, matrix protein p17, transactivator of transcription Tat and reverse transcriptase RT. Gp120, Nef, p17, Tat, and RT cause oxidative stress, can be released from HIV-1-infected cells and are oncogenic. All five are in a position to affect “innocent” bystander cells, specifically, to cause the propagation of (pre)existing malignant and malignant transformation of normal epithelial cells, giving grounds to the direct carcinogenic effects of HIV-1.

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Effect of Strain Variations on Lassa Virus Z Protein-Mediated Human RIG-I Inhibition

Viruses ◽

10.3390/v12090907 ◽

2020 ◽

Vol 12 (9) ◽

pp. 907

Author(s):

Qinfeng Huang ◽

Xiaoying Liu ◽

Morgan Brisse ◽

Hinh Ly ◽

Yuying Liang

Keyword(s):

Matrix Protein ◽

Neurological Diseases ◽

Clinical Manifestations ◽

Hemorrhagic Fever ◽

Lassa Virus ◽

Type I ◽

Human Pathogens ◽

Protein Z ◽

Disease Heterogeneity ◽

Viral Virulence

Mammarenaviruses include several known human pathogens, such as the prototypic lymphocytic choriomeningitis virus (LCMV) that can cause neurological diseases and Lassa virus (LASV) that causes endemic hemorrhagic fever infection. LASV-infected patients show diverse clinical manifestations ranging from asymptomatic infection to hemorrhage, multi-organ failures and death, the mechanisms of which have not been well characterized. We have previously shown that the matrix protein Z of pathogenic arenaviruses, including LASV and LCMV, can strongly inhibit the ability of the innate immune protein RIG-I to suppress type I interferon (IFN-I) expression, which serves as a mechanism of viral immune evasion and virulence. Here, we show that Z proteins of diverse LASV isolates derived from rodents and humans have a high degree of sequence variations at their N- and C-terminal regions and produce variable degrees of inhibition of human RIG-I (hRIG-I) function in an established IFN-β promoter-driven luciferase (LUC) reporter assay. Additionally, we show that Z proteins of four known LCMV strains can also inhibit hRIG-I at variable degrees of efficiency. Collectively, our results confirm that Z proteins of pathogenic LASV and LCMV can inhibit hRIG-I and suggest that strain variations of the Z proteins can influence their efficiency to suppress host innate immunity that might contribute to viral virulence and disease heterogeneity.

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Validation of Inactivation Methods for Arenaviruses

Viruses ◽

10.3390/v13060968 ◽

2021 ◽

Vol 13 (6) ◽

pp. 968

Author(s):

Silke Olschewski ◽

Anke Thielebein ◽

Chris Hoffmann ◽

Olivia Blake ◽

Jonas Müller ◽

...

Keyword(s):

Cell Culture ◽

Hemorrhagic Fever ◽

Downstream Processing ◽

Cell Culture Supernatant ◽

Lassa Virus ◽

Highly Pathogenic ◽

Cell Culture Systems ◽

Pathogenic Viruses ◽

Infected Cells ◽

Biosafety Level

Several of the human-pathogenic arenaviruses cause hemorrhagic fever and have to be handled under biosafety level 4 conditions, including Lassa virus. Rapid and safe inactivation of specimens containing these viruses is fundamental to enable downstream processing for diagnostics or research under lower biosafety conditions. We established a protocol to test the efficacy of inactivation methods using the low-pathogenic Morogoro arenavirus as surrogate for the related highly pathogenic viruses. As the validation of chemical inactivation methods in cell culture systems is difficult due to cell toxicity of commonly used chemicals, we employed filter devices to remove the chemical and concentrate the virus after inactivation and before inoculation into cell culture. Viral replication in the cells was monitored over 4 weeks by using indirect immunofluorescence and immunofocus assay. The performance of the protocol was verified using published inactivation methods including chemicals and heat. Ten additional methods to inactivate virus in infected cells or cell culture supernatant were validated and shown to reduce virus titers to undetectable levels. In summary, we provide a robust protocol for the validation of chemical and physical inactivation of arenaviruses in cell culture, which can be readily adapted to different inactivation methods and specimen matrices.

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Construction and Immunological Evaluation of an Adenoviral Vector-Based Vaccine Candidate for Lassa Fever

Viruses ◽

10.3390/v13030484 ◽

2021 ◽

Vol 13 (3) ◽

pp. 484

Author(s):

Meirong Wang ◽

Ruihua Li ◽

Yaohui Li ◽

Changming Yu ◽

Xiangyang Chi ◽

...

Keyword(s):

Adenoviral Vector ◽

Viral Infections ◽

Vaccine Candidate ◽

Severe Disease ◽

Hemorrhagic Fever ◽

Lassa Fever ◽

Lassa Virus ◽

Glycoprotein Precursor ◽

Vectored Vaccine ◽

Cellular Immune

Lassa virus (LASV) is a rodent-borne arenavirus circulating in West African regions that causes Lassa fever (LF). LF is normally asymptomatic at the initial infection stage, but can progress to severe disease with multiorgan collapse and hemorrhagic fever. To date, the therapeutic choices are limited, and there is no approved vaccine for avoiding LASV infection. Adenoviral vector-based vaccines represent an effective countermeasure against LASV because of their safety and adequate immunogenicity, as demonstrated in use against other emerging viral infections. Here, we constructed and characterized a novel Ad5 (E1-, E3-) vectored vaccine containing the glycoprotein precursor (GPC) of LASV. Ad5-GPCLASV elicited both humoral and cellular immune responses in BALB/c mice. Moreover, a bioluminescent imaging-based BALB/c mouse model infected with GPC-bearing and luciferase-expressing replication-incompetent LASV pseudovirus was utilized to evaluate the vaccine efficacy. The bioluminescence intensity of immunized mice was significantly lower than that of control mice after being inoculated with LASV pseudovirus. This study suggests that Ad5-GPCLASV represents a potential vaccine candidate against LF.

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Dynamics of recurrent viral infection

Proceedings of The Royal Society B Biological Sciences ◽

10.1098/rspb.2006.3563 ◽

2006 ◽

Vol 273 (1598) ◽

pp. 2193-2199 ◽

Cited By ~ 8

Author(s):

W Yao ◽

L Hertel ◽

L.M Wahl

Keyword(s):

Viral Infection ◽

Particle Production ◽

Viral Infections ◽

T Cell Response ◽

Chronic Viral Infection ◽

Viral Production ◽

Infectious Particle ◽

Exogenous Factors ◽

Low Levels ◽

Exogenous Trigger

In chronic viral infection, low levels of viral replication and infectious particle production are maintained over long periods, punctuated by brief bursts of high viral production and release. We apply well-established principles of modelling virus dynamics to the study of chronic viral infection, demonstrating that a model which incorporates the distinct contributions of cytotoxic T lymphocytes (CTLs) and antibodies exhibits long periods of quiescence followed by brief bursts of viral production. This suggests that for recurrent viral infections, no special mechanism or exogenous trigger is necessary to provoke an episode of reactivation; rather, the system may naturally cycle through recurrent episodes at intervals which can be many years long. We also find that exogenous factors which cause small fluctuations in the natural course of the infection can trigger a recurrent episode. Our model predicts that longer periods between recurrences are associated with more severe viral episodes. Four factors move the system towards less frequent, more severe episodes: decreased viral infectivity, decreased CTL efficacy, decreased memory T cell response and increased antibody efficacy.

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Host-Driven Phosphorylation Appears to Regulate the Budding Activity of the Lassa Virus Matrix Protein

Pathogens ◽

10.3390/pathogens7040097 ◽

2018 ◽

Vol 7 (4) ◽

pp. 97 ◽

Cited By ~ 3

Author(s):

Christopher Ziegler ◽

Philip Eisenhauer ◽

Inessa Manuelyan ◽

Marion Weir ◽

Emily Bruce ◽

...

Keyword(s):

Protein Function ◽

Matrix Protein ◽

Rna Virus ◽

Hemorrhagic Fever ◽

Polymerase Activity ◽

Lassa Fever ◽

Lassa Virus ◽

Protein Z ◽

Western Africa ◽

Z Protein

Lassa mammarenavirus (LASV) is an enveloped RNA virus that can cause Lassa fever, an acute hemorrhagic fever syndrome associated with significant morbidity and high rates of fatality in endemic regions of western Africa. The arenavirus matrix protein Z has several functions during the virus life cycle, including coordinating viral assembly, driving the release of new virus particles, regulating viral polymerase activity, and antagonizing the host antiviral response. There is limited knowledge regarding how the various functions of Z are regulated. To investigate possible means of regulation, mass spectrometry was used to identify potential sites of phosphorylation in the LASV Z protein. This analysis revealed that two serines (S18, S98) and one tyrosine (Y97) are phosphorylated in the flexible N- and C-terminal regions of the protein. Notably, two of these sites, Y97 and S98, are located in (Y97) or directly adjacent to (S98) the PPXY late domain, an important motif for virus release. Studies with non-phosphorylatable and phosphomimetic Z proteins revealed that these sites are important regulators of the release of LASV particles and that host-driven, reversible phosphorylation may play an important role in the regulation of LASV Z protein function.

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