Last data update: Apr 22, 2024. (Total: 46599 publications since 2009)
Records 1-27 (of 27 Records) |
Query Trace: Scholte FEM [original query] |
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Characterization of humoral responses to Nipah virus infection in the Syrian Hamster model of disease
Scholte FEM , Rodriguez SE , Welch SR , Davies KA , Genzer SC , Coleman-McCray JD , Harmon JR , Sorvillo TE , Lo MK , Karaaslan E , Bergeron E , Montgomery JM , Spengler JR , Spiropoulou CF . J Infect Dis 2023 Nipah virus (NiV) is a highly pathogenic paramyxovirus. The Syrian hamster model recapitulates key features of human NiV disease and is a critical tool for evaluating antivirals and vaccines. Here we describe longitudinal humoral immune responses in NiV-infected Syrian hamsters. Samples were obtained 1-28 days after infection and analyzed by ELISA, neutralization, and Fc-mediated effector function assays. NiV infection elicited robust antibody responses against the nucleoprotein and attachment glycoprotein. Levels of neutralizing antibodies were modest and only detectable in surviving animals. Fc-mediated effector functions were mostly observed in nucleoprotein-targeting antibodies. Antibody levels and activities positively correlated with challenge dose. |
Vaccination with the Crimean-Congo hemorrhagic fever virus viral replicon vaccine induces NP-based T-cell activation and antibodies possessing Fc-mediated effector functions
Scholte FEM , Karaaslan E , O'Neal TJ , Sorvillo TE , Genzer SC , Welch SR , Coleman-McCray JD , Spengler JR , Kainulainen MH , Montgomery JM , Pegan SD , Bergeron E , Spiropoulou CF . Front Cell Infect Microbiol 2023 13 1233148 Crimean-Congo hemorrhagic fever virus (CCHFV; family Nairoviridae) is a tick-borne pathogen that frequently causes lethal disease in humans. CCHFV has a wide geographic distribution, and cases have been reported in Africa, Asia, the Middle East, and Europe. Availability of a safe and efficacious vaccine is critical for restricting outbreaks and preventing disease in endemic countries. We previously developed a virus-like replicon particle (VRP) vaccine that provides complete protection against homologous and heterologous lethal CCHFV challenge in mice after a single dose. However, the immune responses induced by this vaccine are not well characterized, and correlates of protection remain unknown. Here we comprehensively characterized the kinetics of cell-mediated and humoral immune responses in VRP-vaccinated mice, and demonstrate that they predominantly target the nucleoprotein (NP). NP antibodies are not associated with protection through neutralizing activity, but VRP vaccination results in NP antibodies possessing Fc-mediated antibody effector functions, such as complement activation (ADCD) and antibody-mediated cellular phagocytosis (ADCP). This suggests that Fc-mediated effector functions may contribute to this vaccine's efficacy. |
Single-dose mucosal replicon-particle vaccine protects against lethal Nipah virus infection up to 3 days after vaccination
Welch SR , Spengler JR , Genzer SC , Coleman-McCray JD , Harmon JR , Sorvillo TE , Scholte FEM , Rodriguez SE , O'Neal TJ , Ritter JM , Ficarra G , Davies KA , Kainulainen MH , Karaaslan E , Bergeron É , Goldsmith CS , Lo MK , Nichol ST , Montgomery JM , Spiropoulou CF . Sci Adv 2023 9 (31) eadh4057 Nipah virus (NiV) causes a highly lethal disease in humans who present with acute respiratory or neurological signs. No vaccines against NiV have been approved to date. Here, we report on the clinical impact of a novel NiV-derived nonspreading replicon particle lacking the fusion (F) protein gene (NiVΔF) as a vaccine in three small animal models of disease. A broad antibody response was detected that included immunoglobulin G (IgG) and IgA subtypes with demonstrable Fc-mediated effector function targeting multiple viral antigens. Single-dose intranasal vaccination up to 3 days before challenge prevented clinical signs and reduced virus levels in hamsters and immunocompromised mice; decreases were seen in tissues and mucosal secretions, critically decreasing potential for virus transmission. This virus replicon particle system provides a vital tool to the field and demonstrates utility as a highly efficacious and safe vaccine candidate that can be administered parenterally or mucosally to protect against lethal Nipah disease. |
Mouse models of Ebola virus tolerance and lethality: Characterization of CD-1 mice infected with wild-type, guinea pig-adapted, or mouse-adapted variants
Spengler JR , Welch SR , Ritter JM , Harmon JR , Coleman-McCray JD , Genzer SC , Nascimento Seixas J , Scholte FEM , Davies KA , Bradfute SB , Montgomery JM , Spiropoulou CF . Antiviral Res 2022 210 105496 Development of lethal models of Ebola virus disease has been achieved by the serial passage of virus isolates from human cases in mice and guinea pigs. Use of mice infected with non-adapted virus has been limited due to the absence of overt clinical disease. In recent years, newly recognized sequelae identified in human cases has highlighted the importance of continued investigations of non-lethal infection both in humans and animal models. Here, we revisit the use of rodent-adapted and non-adapted Ebola virus (EBOV) variants in mice to investigate infection tolerance and future utility of these models in pathogenesis and therapeutic intervention studies. We found that like non-adapted wild-type EBOV, guinea pig-adapted EBOV results in widespread tissue infection, variably associated with tissue pathology, and alterations in clinical and immunological analytes in the absence of overt disease. Notably, infection with either non-lethal variant does not greatly differ from lethal mouse-adapted EBOV until near the time end-point criteria are reached in these mice, supporting use of these models of virus tolerance for continued investigations of non-lethal infection and sequelae. |
Viral RNA and infectious virus in mucosal specimens from guinea pigs modeling early phases of lethal and non-lethal Lassa fever
Welch SR , Genzer SC , Coleman-McCray JD , Harmon JR , Scholte FEM , Montgomery JM , Spiropoulou CF , Spengler JR . Emerg Microbes Infect 2022 11 (1) 1-17 ABSTRACTLassa fever (LF) is endemic to broad regions of West Africa. Infection with Lassa virus (LASV), the etiologic agent of LF, results in a spectrum of clinical signs in humans, including severe and lethal hemorrhagic disease. Person-to-person transmission occurs through direct contact with body fluids or contaminated bedding and clothing. To investigate transmission risk in acute LASV infection, we evaluated viral RNA and infectious virus obtained from conjunctival, nasal, oral, genital, and rectal swab specimens from guinea pigs modeling lethal and non-lethal LF. Viral RNA and infectious virus were detected in all specimen types beginning 8 days post infection, prior to onset of fever. In the pre-clinical and clinical period, virus was isolated from a subset of nasal, oral, genital, and rectal swabs, and from all conjunctival swabs. Overall, conjunctival and nasal specimens most frequently yielded infectious virus. These findings indicate mucosal transmission risk based on virus isolation from various sites early in infection and support potential utility of minimally invasive specimen evaluation by RT-qPCR for LASV diagnostics. |
Defective Interfering Viral Particle Treatment Reduces Clinical Signs and Protects Hamsters from Lethal Nipah Virus Disease.
Welch SR , Spengler JR , Harmon JR , Coleman-McCray JD , Scholte FEM , Genzer SC , Lo MK , Montgomery JM , Nichol ST , Spiropoulou CF . mBio 2022 13 (2) e0329421 Defective interfering particles (DIs) contain a considerably smaller genome than the parental virus but retain replication competency. As DIs can directly or indirectly alter propagation kinetics of the parental virus, they offer a novel approach to antiviral therapy, capitalizing on knowledge from natural infection. However, efforts to translate in vitro inhibition to in vivo screening models remain limited. We investigated the efficacy of virus-like particles containing DI genomes (therapeutic infectious particles [TIPs]) in the Syrian hamster model of lethal Nipah virus (NiV) disease. We found that coadministering a high dose of TIPs intraperitoneally with virus challenge improved clinical course and reduced lethality. To mimic natural exposure, we also evaluated lower-dose TIP delivery and virus challenge intranasally, finding equally efficacious reduction in disease severity and overall lethality. Eliminating TIP replicative capacity decreased efficacy, suggesting protection via direct inhibition. These data provide evidence that TIP-mediated treatment can confer protection against disease and lethal outcome in a robust animal NiV model, supporting further development of TIP treatment for NiV and other high-consequence pathogens. IMPORTANCE Here, we demonstrate that treatment with defective interfering particles (DIs), a natural by-product of viral infection, can significantly improve the clinical course and outcome of viral disease. When present with their parental virus, DIs can directly or indirectly alter viral propagation kinetics and exert potent inhibitory properties in cell culture. We evaluated the efficacy of a selection of virus-like particles containing DI genomes (TIPs) delivered intranasally in a lethal hamster model of Nipah virus disease. We demonstrate significantly improved clinical outcomes, including reduction in both lethality and the appearance of clinical signs. This work provides key efficacy data in a robust model of Nipah virus disease to support further development of TIP-mediated treatment against high-consequence viral pathogens. |
Lassa virus replicon particle vaccine protects strain 13/N guinea pigs against challenge with geographically and genetically diverse viral strains.
Spengler JR , Kainulainen MH , Welch SR , Coleman-McCray JAD , Harmon JR , Condrey JA , Scholte FEM , Nichol ST , Montgomery JM , Albariño CG , Spiropoulou CF . J Infect Dis 2022 226 (9) 1545-1550 Lassa virus (LASV) causes mild to severe hemorrhagic fever disease in humans. Strain 13/N guinea pigs are highly susceptible to infection with LASV strain Josiah (clade IV), providing a critical model system for therapeutics and vaccine development. To develop additional models of disease, we detail the clinical course in guinea pigs infected with 5 geographically and genetically diverse LASV strains. Two of the developed models (LASV clades II and III) were then used to evaluate efficacy of a virus replicon particle (VRP) vaccine against heterologous LASV challenge, demonstrating complete protection against clinical disease after a single vaccination dose. |
The Structure and Immune Regulatory Implications of the Ubiquitin-Like Tandem Domain Within an Avian 2'-5' Oligoadenylate Synthetase-Like Protein.
Shepard JD , Freitas BT , Rodriguez SE , Scholte FEM , Baker K , Hutchison MR , Longo JE , Miller HC , O'Boyle BM , Tandon A , Zhao P , Grimsey NJ , Wells L , Bergeron É , Pegan SD . Front Immunol 2021 12 794664 Post-translational modification of host and viral proteins by ubiquitin and ubiquitin-like proteins plays a key role in a host's ability to mount an effective immune response. Avian species lack a ubiquitin-like protein found in mammals and other non-avian reptiles; interferon stimulated gene product 15 (ISG15). ISG15 serves as a messenger molecule and can be conjugated to both host and viral proteins leading them to be stabilized, degraded, or sequestered. Structurally, ISG15 is comprised of a tandem ubiquitin-like domain (Ubl), which serves as the motif for post-translational modification. The 2'-5' oligoadenylate synthetase-like proteins (OASL) also encode two Ubl domains in series near its C-terminus which binds OASL to retinoic acid inducible gene-I (RIG-I). This protein-protein interaction increases the sensitivity of RIG-I and results in an enhanced production of type 1 interferons and a robust immune response. Unlike human and other mammalian OASL homologues, avian OASLs terminate their tandem Ubl domains with the same LRLRGG motif found in ubiquitin and ISG15, a motif required for their conjugation to proteins. Chickens, however, lack RIG-I, raising the question of structural and functional characteristics of chicken OASL (chOASL). By investigating chOASL, the evolutionary history of viruses with deubiquitinases can be explored and drivers of species specificity for these viruses may be uncovered. Here we show that the chOASL tandem Ubl domains shares structural characteristics with mammalian ISG15, and that chOASL can oligomerize and conjugate to itself. In addition, the ISG15-like features of avian OASLs and how they impact interactions with viral deubiquitinases and deISGylases are explored. |
Viral replicon particles protect IFNAR(-/-) mice against lethal Crimean-Congo hemorrhagic fever virus challenge three days after vaccination
Spengler JR , Welch SR , Scholte FEM , Rodriguez SE , Harmon JR , Coleman-McCray JD , Nichol ST , Montgomery JM , Bergeron É , Spiropoulou CF . Antiviral Res 2021 191 105090 Crimean-Congo hemorrhagic fever virus (CCHFV) causes mild to severe and fatal disease in humans. Person-to-person transmission is common, necessitating the availability of rapidly deliverable therapeutic and prophylactic interventions to mitigate CCHFV spread. Previously, we showed complete protection using one dose of a viral replicon particle (VRP) vaccine administered 28 days before CCHFV challenge. In order to determine the utility of the VRP vaccine for rapid vaccination protocols, we assessed the efficacy of such vaccination administered at various intervals relative to challenge in IFNAR(-/-) mice. Unvaccinated mice uniformly succumbed to disease by 8 days post infection (dpi). All mice vaccinated 14, 7, or 3 days prior to CCHFV challenge survived infection. Mice vaccinated -14 or -7 dpi were fully protected from clinical disease, whereas mice inoculated -3 dpi developed signs of disease prior to recovering to baseline values 5-9 dpi. These data support the utility of the VRP vaccine for modified short course vaccination protocols to protect against disease and severe outcomes. |
How ISG15 combats viral infection.
Freitas BT , Scholte FEM , Bergeron E , Pegan SD . Virus Res 2020 286 198036 Interferon (IFN)-stimulated gene product 15 (ISG15) is a ubiquitin-like protein critical for the control of microbial infections. ISG15 appears to serve a wide variety of functions, which regulate multiple cellular responses contributing to the development of an antiviral state. ISG15 is a versatile molecule directly modulating both host and virus protein function which regulate many signaling pathways, including its own synthesis. Here we review the various roles ISG15 plays in the antiviral immune response, and examine the mechanisms by which viruses attempt to mitigate or exploit ISG15 activity. |
The Crimean-Congo Hemorrhagic Fever Virus NSm Protein is Dispensable for Growth In Vitro and Disease in Ifnar -/- Mice.
Welch SR , Scholte FEM , Spengler JR , Ritter JM , Coleman-McCray JD , Harmon JR , Nichol ST , Zaki SR , Spiropoulou CF , Bergeron E . Microorganisms 2020 8 (5) Crimean-Congo hemorrhagic fever virus (CCHFV) is a tri-segmented, tick-borne nairovirus that causes disease of ranging severity in humans. The CCHFV M segment encodes a complex glycoprotein precursor (GPC) that undergoes extensive endoproteolytic cleavage, giving rise to two structural proteins (Gn and Gc) required for virus attachment and entry, and to multiple non-structural proteins (NSm, GP160, GP85, and GP38). The functions of these non-structural proteins remain largely unclear. Here, we investigate the role of NSm during infection by generating a recombinant CCHFV lacking the complete NSm domain (10200NSm) and observing CCHFV NSm replication in cell lines and pathogenicity in Ifnar(-/-) mice. Our data demonstrate that the NSm domain is dispensable for viral replication in vitro, and, despite the delayed onset of clinical signs, CCHFV lacking this domain caused severe or lethal disease in infected mice. |
Inhibition of Nipah Virus by Defective Interfering Particles.
Welch SR , Tilston NL , Lo MK , Whitmer SLM , Harmon JR , Scholte FEM , Spengler JR , Duprex WP , Nichol ST , Spiropoulou CF . J Infect Dis 2020 221 S460-S470 The error-prone nature of ribonucleic acid (RNA)-dependent RNA polymerases drives the diversity of RNA virus populations. Arising within this diversity is a subset of defective viral genomes that retain replication competency, termed defective interfering (DI) genomes. These defects are caused by aberrant viral polymerase reinitiation on the same viral RNA template (deletion DI species) or the nascent RNA strand (copyback DI species). Defective interfering genomes have previously been shown to alter the dynamics of a viral population by interfering with normal virus replication and/or by stimulating the innate immune response. In this study, we investigated the ability of artificially produced DI genomes to inhibit Nipah virus (NiV), a highly pathogenic biosafety level 4 paramyxovirus. High multiplicity of infection passaging of both NiV clinical isolates and recombinant NiV in Vero cells generated an extensive DI population from which individual DIs were identified using next-generation sequencing techniques. Assays were established to generate and purify both naturally occurring and in silico-designed DIs as fully encapsidated, infectious virus-like particles termed defective interfering particles (DIPs). We demonstrate that several of these NiV DIP candidates reduced NiV titers by up to 4 logs in vitro. These data represent a proof-of-principle that a therapeutic application of DIPs to combat NiV infections may be an alternative source of antiviral control for this disease. |
Griffithsin inhibits Nipah virus entry and fusion and can protect Syrian golden hamsters from lethal Nipah virus challenge
Lo MK , Spengler JR , Krumpe LRH , Welch SR , Chattopadhyay A , Harmon JR , Coleman-McCray JD , Scholte FEM , Hotard AL , Fuqua JL , Rose JK , Nichol ST , Palmer KE , O'Keefe BR , Spiropoulou CF . J Infect Dis 2020 221 S480-S492 Nipah virus (NiV) is a highly pathogenic zoonotic paramyxovirus that causes fatal encephalitis and respiratory disease in humans. There is currently no approved therapeutic for human use against NiV infection. Griffithsin (GRFT) is high-mannose oligosaccharide binding lectin that has shown in vivo broad-spectrum activity against viruses including severe acute respiratory syndrome coronavirus, human immunodeficiency virus 1, hepatitis C virus, and Japanese encephalitis virus. In this study, we evaluated the in vitro antiviral activities of GRFT and its synthetic trimeric tandemer (3mG) against NiV and other viruses from across 4 virus families. The 3mG had comparatively greater potency than GRFT against NiV due to its enhanced ability to block NiV glycoprotein-induced syncytia formation. Our initial in vivo prophylactic evaluation of an oxidation-resistant GRFT (Q-GRFT) showed significant protection against lethal NiV challenge in Syrian golden hamsters. Our results warrant further development of Q-GRFT and 3mG as potential NiV therapeutics. |
Determining the molecular drivers of species-specific interferon-stimulated gene product 15 interactions with nairovirus ovarian tumor domain proteases.
Dzimianski JV , Scholte FEM , Williams IL , Langley C , Freitas BT , Spengler JR , Bergeron E , Pegan SD . PLoS One 2019 14 (12) e0226415 Tick-borne nairoviruses (order Bunyavirales) encode an ovarian tumor domain protease (OTU) that suppresses the innate immune response by reversing the post-translational modification of proteins by ubiquitin (Ub) and interferon-stimulated gene product 15 (ISG15). Ub is highly conserved across eukaryotes, whereas ISG15 is only present in vertebrates and shows substantial sequence diversity. Prior attempts to address the effect of ISG15 diversity on viral protein-ISG15 interactions have focused on only a single species' ISG15 or a limited selection of nairovirus OTUs. To gain a more complete perspective of OTU-ISG15 interactions, we biochemically assessed the relative activities of 14 diverse nairovirus OTUs for 12 species' ISG15 and found that ISG15 activity is predominantly restricted to particular nairovirus lineages reflecting, in general, known virus-host associations. To uncover the underlying molecular factors driving OTUs affinity for ISG15, X-ray crystal structures of Kupe virus and Ganjam virus OTUs bound to sheep ISG15 were solved and compared to complexes of Crimean-Congo hemorrhagic fever virus and Erve virus OTUs bound to human and mouse ISG15, respectively. Through mutational and structural analysis seven residues in ISG15 were identified that predominantly influence ISG15 species specificity among nairovirus OTUs. Additionally, OTU residues were identified that influence ISG15 preference, suggesting the potential for viral OTUs to adapt to different host ISG15s. These findings provide a foundation to further develop research methods to trace nairovirus-host relationships and delineate the full impact of ISG15 diversity on nairovirus infection. |
Fluorescent Crimean-Congo hemorrhagic fever virus illuminates tissue tropism patterns and identifies early mononuclear phagocytic cell targets in IFNAR-/- mice
Welch SR , Ritter JM , McElroy AK , Harmon JR , Coleman-McCray JD , Scholte FEM , Kobinger GP , Bergeron E , Zaki SR , Nichol ST , Spengler JR , Spiropoulou CF . PLoS Pathog 2019 15 (12) e1008183 Crimean-Congo hemorrhagic fever virus (CCHFV, order Bunyavirales, family Nairoviridae, genus Orthonairovirus) is the tick-borne etiological agent of Crimean-Congo hemorrhagic fever (CCHF) in humans. Animals are generally susceptible to CCHFV infection but refractory to disease. Small animal models are limited to interferon-deficient mice, that develop acute fatal disease following infection. Here, using a ZsGreen1- (ZsG) expressing reporter virus (CCHFV/ZsG), we examine tissue tropism and dissemination of virus in interferon-alpha/beta receptor knock-out (Ifnar-/-) mice. We demonstrate that CCHFV/ZsG retains in vivo pathogenicity comparable to wild-type virus. Interestingly, despite high levels of viral RNA in all organs assessed, 2 distribution patterns of infection were observed by both fluorescence and immunohistochemistry (IHC), corresponding to the permissiveness of organ tissues. To further investigate viral dissemination and to temporally define cellular targets of CCHFV in vivo, mice were serially euthanized at different stages of disease. Flow cytometry was used to characterize CCHFV-associated alterations in hematopoietic cell populations and to classify infected cells in the blood, lymph node, spleen, and liver. ZsG signal indicated that mononuclear phagocytic cells in the lymphatic tissues were early targets of infection; in late-stage infection, overall, the highest levels of signal were detected in the liver, and ZsG was found in both antigen-presenting and lymphocyte cell populations. |
Alterations in blood chemistry levels associated with Nipah virus disease in the Syrian hamster model
Genzer SC , Welch SR , Scholte FEM , Harmon JR , Coleman-McCray JD , Lo MK , Montgomery JM , Nichol ST , Spiropoulou CF , Spengler JR . J Infect Dis 2019 221 S454-S459 Nipah virus ([NiV] family Paramyxoviridae, genus Henipavirus) infection can cause severe respiratory and neurological disease in humans. The pathophysiology of disease is not fully understood, and it may vary by presentation and clinical course. In this study, we investigate changes in blood chemistry in NiV-infected Syrian hamsters that survived or succumbed to disease. Increased sodium and magnesium and decreased albumin and lactate levels were detected in animals euthanized with severe clinical disease compared with mock-infected controls. When subjects were grouped by clinical syndrome, additional trends were discernable, highlighting changes associated with either respiratory or neurological disease. |
Evaluation of a single-dose nucleoside-modified messenger RNA vaccine encoding hendra virus-soluble glycoprotein against lethal Nipah virus challenge in Syrian Hamsters
Lo MK , Spengler JR , Welch SR , Harmon JR , Coleman-Mccray JD , Scholte FEM , Shrivastava-Ranjan P , Montgomery JM , Nichol ST , Weissman D , Spiropoulou CF . J Infect Dis 2019 221 S493-S498 In the absence of approved vaccines and therapeutics for use in humans, Nipah virus continues to cause fatal outbreaks of encephalitis and respiratory disease in Bangladesh and India on a near-annual basis. We determined that a single dose of a lipid nanoparticle nucleoside-modified messenger RNA vaccine encoding the soluble Hendra virus glycoprotein protected up to 70% of Syrian hamsters from lethal NiV challenge, despite animals having suboptimally primed immune responses before challenge. These data provide a foundation from which to optimize future messenger RNA vaccination studies against NiV and other highly pathogenic viruses. |
In situ imaging of fluorescent Nipah virus respiratory and neurological tissue tropism in the Syrian hamster model
Welch SR , Scholte FEM , Harmon JR , Coleman-McCray JD , Lo MK , Montgomery JM , Nichol ST , Spiropoulou CF , Spengler JR . J Infect Dis 2019 221 S448-S453 Using a recombinant Nipah virus expressing a fluorescent protein (ZsG), we visualized virus tropism in the Syrian hamster model. We found that anatomical localization of fluorescence correlated to clinical signs; signal was primarily visualized in the respiratory tract in animals with acute-onset terminal disease, whereas central nervous system localization was seen in animals that succumbed with delayed disease onset. While polymerase chain reaction (PCR) detection corresponded well to ZsG signal, virus was only isolated from some lung, brain, liver, and kidney samples that were ZsG and/or PCR positive, and only from animals euthanized on or before 15 days post infection. |
Heterologous protection against Crimean-Congo hemorrhagic fever in mice after a single dose of replicon particle vaccine
Spengler JR , Welch SR , Scholte FEM , Coleman-McCray JD , Harmon JR , Nichol ST , Bergeron E , Spiropoulou CF . Antiviral Res 2019 170 104573 No vaccines are currently licensed to prevent Crimean-Congo hemorrhagic fever virus (CCHFV) infection, which can cause mild self-limiting clinical signs or severe, often fatal hemorrhagic fever disease. Here we continued investigations into the utility of a single-dose virus replicon particle (VRP) vaccine regimen by assessing protection against Turkey or Oman strains of CCHFV. We found that all mice were completely protected from disease, supporting broad applicability of this platform for CCHFV prevention. |
Stable Occupancy of the Crimean-Congo Hemorrhagic Fever Virus-Encoded Deubiquitinase Blocks Viral Infection.
Scholte FEM , Hua BL , Spengler JR , Dzimianski JV , Coleman-McCray JD , Welch SR , McMullan LK , Nichol ST , Pegan SD , Spiropoulou CF , Bergeron E . mBio 2019 10 (4) Crimean-Congo hemorrhagic fever virus (CCHFV) infection can result in a severe hemorrhagic syndrome for which there are no antiviral interventions available to date. Certain RNA viruses, such as CCHFV, encode cysteine proteases of the ovarian tumor (OTU) family that antagonize interferon (IFN) production by deconjugating ubiquitin (Ub). The OTU of CCHFV, a negative-strand RNA virus, is dispensable for replication of the viral genome, despite being part of the large viral RNA polymerase. Here, we show that mutations that prevent binding of the OTU to cellular ubiquitin are required for the generation of recombinant CCHFV containing a mutated catalytic cysteine. Similarly, the high-affinity binding of a synthetic ubiquitin variant (UbV-CC4) to CCHFV OTU strongly inhibits viral growth. UbV-CC4 inhibits CCHFV infection even in the absence of intact IFN signaling, suggesting that its antiviral activity is not due to blocking the OTU's immunosuppressive function. Instead, the prolonged occupancy of the OTU with UbV-CC4 directly targets viral replication by interfering with CCHFV RNA synthesis. Together, our data provide mechanistic details supporting the development of antivirals targeting viral OTUs.IMPORTANCE Crimean-Congo hemorrhagic fever virus is an important human pathogen with a wide global distribution for which no therapeutic interventions are available. CCHFV encodes a cysteine protease belonging to the ovarian tumor (OTU) family which is involved in host immune suppression. Here we demonstrate that artificially prolonged binding of the OTU to a substrate inhibits virus infection. This provides novel insights into CCHFV OTU function during the viral replicative cycle and highlights the OTU as a potential antiviral target. |
Protection from lethal Lassa disease can be achieved both before and after virus exposure by administration of single-cycle replicating Lassa virus replicon particles.
Kainulainen MH , Spengler JR , Welch SR , Coleman-McCray JD , Harmon JR , Scholte FEM , Goldsmith CS , Nichol ST , Albarino CG , Spiropoulou CF . J Infect Dis 2019 220 (8) 1281-1289 Lassa fever is a frequently severe human disease that is endemic to several countries in West Africa. To date, no licensed vaccines are available to prevent Lassa virus (LASV) infection, even though Lassa fever is thought to be an important disease contributing to mortality and both acute and chronic morbidity. We have previously described a vaccine candidate composed of single-cycle LASV replicon particles (VRPs) and a stable cell line for their production. Here, we refine the genetic composition of the VRPs and demonstrate the ability to reproducibly purify them with high yields. Studies in the guinea pig model confirm efficacy of the vaccine candidate, demonstrate that single-cycle replication is necessary for complete protection by the VRP vaccine, and show that post-exposure vaccination can confer protection from lethal outcome. |
Single-dose replicon particle vaccine provides complete protection against Crimean-Congo hemorrhagic fever virus in mice
Scholte FEM , Spengler JR , Welch SR , Harmon JR , Coleman-McCray JD , Freitas BT , Kainulainen MH , Pegan SD , Nichol ST , Bergeron E , Spiropoulou CF . Emerg Microbes Infect 2019 8 (1) 575-578 Crimean-Congo hemorrhagic fever virus (CCHFV) is an emerging tick-borne virus from the family Nairoviridae that frequently causes lethal disease in humans. CCHFV has a wide geographic distribution, and cases have been reported in Africa, Asia, the Middle East, and Europe. Recent autochthonous cases in Spain demonstrate the emergence of CCHFV in previously naïve regions [1]. CCHFV is considered a public health threat due to its epidemic potential, high case fatality rate, and lack of treatment options. Currently, no antivirals or licensed vaccines with proven efficacy are available. CCHFV was recently included on the World Health Organization Research and Development Blueprint list of infectious agents critically needing effective prophylaxis and therapeutics to prevent major outbreaks. Development of a safe and efficacious vaccine is critical for restricting future outbreaks and preventing disease in endemic countries. In an outbreak situation, a CCHFV vaccine should ideally confer maximal protection after administration of a single dose to rapidly protect at-risk populations. |
ISG15: It's complicated
Dzimianski JV , Scholte FEM , Bergeron E , Pegan SD . J Mol Biol 2019 431 (21) 4203-4216 Interferon-stimulated gene product 15 (ISG15) is a key component of host responses to microbial infection. Despite having been known for four decades, grasping the functions and features of ISG15 has been a slow and elusive process. Substantial work over the past two decades has greatly enhanced this understanding, revealing the complex and variable nature of this protein. This has unveiled multiple mechanisms of action that are only now beginning to be understood. In addition, it has uncovered diversity not only between how ISG15 affects different pathogens but also between the function and structure of ISG15 itself between different host species. Here we review the complexity of ISG15 within the context of viral infection, focusing primarily on its antiviral function and the mechanisms viruses employ to thwart its effects. We highlight what is known regarding the impact of ISG15 sequence and structural diversity on these interactions and discuss the aspects presenting the next frontier toward elucidating a more complete picture of ISG15 function. |
Probing the impact of nairovirus genomic diversity on viral ovarian tumor domain protease (vOTU) structure and deubiquitinase activity.
Dzimianski JV , Beldon BS , Daczkowski CM , Goodwin OY , Scholte FEM , Bergeron E , Pegan SD . PLoS Pathog 2019 15 (1) e1007515 Post-translational modification of host and viral proteins by ubiquitin (Ub) and Ub-like proteins, such as interferon stimulated gene product 15 (ISG15), plays a key role in response to infection. Viruses have been increasingly identified that contain proteases possessing deubiquitinase (DUB) and/or deISGylase functions. This includes viruses in the Nairoviridae family that encode a viral homologue of the ovarian tumor protease (vOTU). vOTU activity was recently demonstrated to be critical for replication of the often-fatal Crimean-Congo hemorrhagic fever virus, with DUB activity suppressing the type I interferon responses and deISGylase activity broadly removing ISG15 conjugated proteins. There are currently about 40 known nairoviruses classified into fourteen species. Recent genomic characterization has revealed a high degree of diversity, with vOTUs showing less than 25% amino acids identities within the family. Previous investigations have been limited to only a few closely related nairoviruses, leaving it unclear what impact this diversity has on vOTU function. To probe the effects of vOTU diversity on enzyme activity and specificity, we assessed representative vOTUs spanning the Nairoviridae family towards Ub and ISG15 fluorogenic substrates. This revealed great variation in enzymatic activity and specific substrate preferences. A subset of the vOTUs were further assayed against eight biologically relevant di-Ub substrates, uncovering both common trends and distinct preferences of poly-Ub linkages by vOTUs. Four novel X-ray crystal structures were obtained that provide a biochemical rationale for vOTU substrate preferences and elucidate structural features that distinguish the vOTUs, including a motif in the Hughes orthonairovirus species that has not been previously observed in OTU domains. Additionally, structure-informed mutagenesis provided the first direct evidence of a second site involved in di-Ub binding for vOTUs. These results provide new insight into nairovirus evolution and pathogenesis, and further enhances the development of tools for therapeutic purposes. |
The S Genome Segment Is Sufficient to Maintain Pathogenicity in Intra-Clade Lassa Virus Reassortants in a Guinea Pig Model.
Welch SR , Scholte FEM , Albarino CG , Kainulainen MH , Coleman-McCray JD , Guerrero LW , Chakrabarti AK , Klena JD , Nichol ST , Spengler JR , Spiropoulou CF . Front Cell Infect Microbiol 2018 8 240 Genome reassortment in Lassa virus (LASV) has been reported in nature, but phenotypic consequences of this phenomenon are not well described. Here we characterize, both in vitro and in vivo, reassortment between 2 LASV strains: the prototypic 1976 Josiah strain and a more recently isolated 2015 Liberian strain. In vitro analysis showed that although cis- and trans-acting elements of viral RNA synthesis were compatible between strains, reassortants demonstrated different levels of viral replication. These differences were also apparent in vivo, as reassortants varied in pathogenicity in the guinea pig model of LASV infection. The reassortant variant containing the Josiah S segment retained the virulence of the parental Josiah strain, but the reassortant variant containing the S segment of the Liberian isolate was highly attenuated compared to both parental strains. Contrary to observations in reassortants between LASV and other arenavirus species, which suggest that L segment-encoded factors are responsible for virulence, these studies highlight a role for S segment-encoded virulence factors in disease, and also suggest that inefficient interactions between proteins of heterologous strains may limit the prevalence of reassortant LASV variants in nature. |
Identification of 2'-deoxy-2'-fluorocytidine as a potent inhibitor of Crimean-Congo hemorrhagic fever virus replication using a recombinant fluorescent reporter virus
Welch SR , Scholte FEM , Flint M , Chatterjee P , Nichol ST , Bergeron E , Spiropoulou CF . Antiviral Res 2017 147 91-99 Crimean-Congo hemorrhagic fever virus (CCHFV), a tick-borne orthonairovirus, causes a severe hemorrhagic disease in humans (Crimean-Congo hemorrhagic fever, CCHF). Currently, no vaccines are approved to prevent CCHF; treatment is limited to supportive care and the use of ribavirin, the therapeutic benefits of which remain unclear. CCHF is part of WHO's priority list of infectious diseases warranting further research and development. To aid in the identification of new antiviral compounds, we generated a recombinant CCHFV expressing a reporter protein, allowing us to quantify virus inhibition by measuring the reduction in fluorescence in infected cells treated with candidate compounds. The screening assay was readily adaptable to high-throughput screening (HTS) of compounds using Huh7 cells, with a signal-to-noise ratio of 50:1, and Z'-factors > 0.6 in both 96- and 384-well formats. A screen of candidate nucleoside analog compounds identified 2'-deoxy-2'-fluorocytidine (EC50 = 61 +/- 18 nM) as having 200 x the potency of ribavirin (EC50 = 12.5 +/- 2.6 muM), as well as 17 x the potency of T-705 (favipiravir), another compound with reported anti-CCHFV activity (EC50 = 1.03 +/- 0.16 muM). Furthermore, we also determined that 2'-deoxy-2'-fluorocytidine acts synergistically with T-705 to inhibit CCHFV replication without causing cytotoxicity. The incorporation of this reporter virus into the high-throughput screening assay described here will allow more rapid identification of effective therapeutic options to combat this emerging human pathogen. |
Crimean-Congo hemorrhagic fever virus suppresses innate immune responses via a ubiquitin and ISG15 specific protease
Scholte FEM , Zivcec M , Dzimianski JV , Deaton MK , Spengler JR , Welch SR , Nichol ST , Pegan SD , Spiropoulou CF , Bergeron E . Cell Rep 2017 20 (10) 2396-2407 Antiviral responses are regulated by conjugation of ubiquitin (Ub) and interferon-stimulated gene 15 (ISG15) to proteins. Certain classes of viruses encode Ub- or ISG15-specific proteases belonging to the ovarian tumor (OTU) superfamily. Their activity is thought to suppress cellular immune responses, but studies demonstrating the function of viral OTU proteases during infection are lacking. Crimean-Congo hemorrhagic fever virus (CCHFV, family Nairoviridae) is a highly pathogenic human virus that encodes an OTU with both deubiquitinase and deISGylase activity as part of the viral RNA polymerase. We investigated CCHFV OTU function by inactivating protease catalytic activity or by selectively disrupting its deubiquitinase and deISGylase activity using reverse genetics. CCHFV OTU inactivation blocked viral replication independently of its RNA polymerase activity, while deubiquitinase activity proved critical for suppressing the interferon responses. Our findings provide insights into viral OTU functions and support the development of therapeutics and vaccines. |
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