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Linfa Wang - One of the best experts on this subject based on the ideXlab platform.

  • structural and functional analyses reveal promiscuous and species specific use of ephrin receptors by cedar virus
    Proceedings of the National Academy of Sciences of the United States of America, 2019
    Co-Authors: Eric D Laing, Sofia Cheliout Da Silva, Stephanie R Petzing, Spencer L Sterling, Chanakha K Navaratnarajah, Linfa Wang, Glenn A. Marsh, Yan Xu, Moushimi Amaya, Dimitar B Nikolov
    Abstract:

    Cedar virus (CedV) is a bat-borne Henipavirus related to Nipah virus (NiV) and Hendra virus (HeV), zoonotic agents of fatal human disease. CedV receptor-binding protein (G) shares only ∼30% sequence identity with those of NiV and HeV, although they can all use ephrin-B2 as an entry receptor. We demonstrate that CedV also enters cells through additional B- and A-class ephrins (ephrin-B1, ephrin-A2, and ephrin-A5) and report the crystal structure of the CedV G ectodomain alone and in complex with ephrin-B1 or ephrin-B2. The CedV G receptor-binding site is structurally distinct from other Henipaviruses, underlying its capability to accommodate additional ephrin receptors. We also show that CedV can enter cells through mouse ephrin-A1 but not human ephrin-A1, which differ by 1 residue in the key contact region. This is evidence of species specific ephrin receptor usage by a Henipavirus, and implicates additional ephrin receptors in potential zoonotic transmission.

  • Rescue and characterization of recombinant cedar virus, a non-pathogenic Henipavirus species.
    Virology Journal, 2018
    Co-Authors: Eric D Laing, Chanakha K Navaratnarajah, Linfa Wang, Moushimi Amaya, Yan Ru Feng, Roberto Cattaneo, Christopher C Broder
    Abstract:

    Hendra virus and Nipah virus are zoonotic viruses that have caused severe to fatal disease in livestock and human populations. The isolation of Cedar virus, a non-pathogenic virus species in the genus Henipavirus, closely-related to the highly pathogenic Hendra virus and Nipah virus offers an opportunity to investigate differences in pathogenesis and receptor tropism among these viruses. We constructed full-length cDNA clones of Cedar virus from synthetic oligonucleotides and rescued two replication-competent, recombinant Cedar virus variants: a recombinant wild-type Cedar virus and a recombinant Cedar virus that expresses a green fluorescent protein from an open reading frame inserted between the phosphoprotein and matrix genes. Replication kinetics of both viruses and stimulation of the interferon pathway were characterized in vitro. Cellular tropism for ephrin-B type ligands was qualitatively investigated by microscopy and quantitatively by a split-luciferase fusion assay. Successful rescue of recombinant Cedar virus expressing a green fluorescent protein did not significantly affect virus replication compared to the recombinant wild-type Cedar virus. We demonstrated that recombinant Cedar virus stimulated the interferon pathway and utilized the established Hendra virus and Nipah virus receptor, ephrin-B2, but not ephrin-B3 to mediate virus entry. We further characterized virus-mediated membrane fusion kinetics of Cedar virus with the known Henipavirus receptors ephrin-B2 and ephrin-B3. The recombinant Cedar virus platform may be utilized to characterize the determinants of pathogenesis across the Henipaviruses, investigate their receptor tropisms, and identify novel pan-Henipavirus antivirals. Moreover, these experiments can be conducted safely under BSL-2 conditions.

  • Rescue and characterization of recombinant cedar virus, a non-pathogenic Henipavirus species
    BMC, 2018
    Co-Authors: Eric D Laing, Chanakha K Navaratnarajah, Linfa Wang, Moushimi Amaya, Yan Ru Feng, Roberto Cattaneo, Christopher C Broder
    Abstract:

    Abstract Background Hendra virus and Nipah virus are zoonotic viruses that have caused severe to fatal disease in livestock and human populations. The isolation of Cedar virus, a non-pathogenic virus species in the genus Henipavirus, closely-related to the highly pathogenic Hendra virus and Nipah virus offers an opportunity to investigate differences in pathogenesis and receptor tropism among these viruses. Methods We constructed full-length cDNA clones of Cedar virus from synthetic oligonucleotides and rescued two replication-competent, recombinant Cedar virus variants: a recombinant wild-type Cedar virus and a recombinant Cedar virus that expresses a green fluorescent protein from an open reading frame inserted between the phosphoprotein and matrix genes. Replication kinetics of both viruses and stimulation of the interferon pathway were characterized in vitro. Cellular tropism for ephrin-B type ligands was qualitatively investigated by microscopy and quantitatively by a split-luciferase fusion assay. Results Successful rescue of recombinant Cedar virus expressing a green fluorescent protein did not significantly affect virus replication compared to the recombinant wild-type Cedar virus. We demonstrated that recombinant Cedar virus stimulated the interferon pathway and utilized the established Hendra virus and Nipah virus receptor, ephrin-B2, but not ephrin-B3 to mediate virus entry. We further characterized virus-mediated membrane fusion kinetics of Cedar virus with the known Henipavirus receptors ephrin-B2 and ephrin-B3. Conclusions The recombinant Cedar virus platform may be utilized to characterize the determinants of pathogenesis across the Henipaviruses, investigate their receptor tropisms, and identify novel pan-Henipavirus antivirals. Moreover, these experiments can be conducted safely under BSL-2 conditions

  • A Functional Genomics Approach to Henipavirus Research: The Role of Nuclear Proteins, MicroRNAs and Immune Regulators in Infection and Disease
    Roles of Host Gene and Non-coding RNA Expression in Virus Infection, 2017
    Co-Authors: Cameron R. Stewart, Chwan Hong Foo, Celine Deffrasnes, Andrew G.d. Bean, Linfa Wang
    Abstract:

    Hendra and Nipah viruses (family Paramyxoviridae, genus Henipavirus) are zoonotic RNA viruses that cause lethal disease in humans and are designated as Biosafety Level 4 (BSL4) agents. Moreover, Henipaviruses belong to the same group of viruses that cause disease more commonly in humans such as measles, mumps and respiratory syncytial virus. Due to the relatively recent emergence of the Henipaviruses and the practical constraints of performing functional genomics studies at high levels of containment, our understanding of the Henipavirus infection cycle is incomplete. In this chapter we describe recent loss-of-function (i.e. RNAi) functional genomics screens that shed light on the Henipavirus–host interface at a genome-wide level. Further to this, we cross-reference RNAi results with studies probing host proteins targeted by Henipavirus proteins, such as nuclear proteins and immune modulators. These functional genomics studies join a growing body of evidence demonstrating that nuclear and nucleolar host proteins play a crucial role in Henipavirus infection. Furthermore these studies will underpin future efforts to define the role of nucleolar host–virus interactions in infection and disease.

  • Nuclear localization and secretion competence are conserved among Henipavirus matrix proteins.
    Journal of General Virology, 2017
    Co-Authors: Elisabeth C Mclinton, Linfa Wang, Glenn A. Marsh, Kylie M. Wagstaff, Alexander Lee, Gregory W. Moseley, David A. Jans, Kim G. Lieu, Hans J. Netter
    Abstract:

    Viruses of the genus Henipavirus of the family Paramyxoviridae are zoonotic pathogens, which have emerged in Southeast Asia, Australia and Africa. Nipah virus (NiV) and Hendra virus are highly virulent pathogens transmitted from bats to animals and humans, while the Henipavirus Cedar virus seems to be non-pathogenic in infection studies. The full replication cycle of the Paramyxoviridae occurs in the host cell’s cytoplasm, where viral assembly is orchestrated by the matrix (M) protein. Unexpectedly, the NiV-M protein traffics through the nucleus as an essential step to engage the plasma membrane in preparation for viral budding/release. Comparative studies were performed to assess whether M protein nuclear localization is a common feature of the Henipaviruses, including the recently sequenced (although not yet isolated) Ghanaian bat Henipavirus (Kumasi virus, GH-M74a virus) and Mojiang virus. Live-cell confocal microscopy revealed that nuclear translocation of GFP-fused M protein is conserved between Henipaviruses in both human- and bat-derived cell lines. However, the efficiency of M protein nuclear localization and virus-like particle budding competency varied. Additionally, Cedar virus-, Kumasi virus- and Mojiang virus-M proteins were mutated in a bipartite nuclear localization signal, indicating that a key lysine residue is essential for nuclear import, export and induction of budding events, as previously reported for NiV-M. The results of this study suggest that the M proteins of Henipaviruses may utilize a similar nucleocytoplasmic trafficking pathway as an essential step during viral replication in both humans and bats.

Christopher C Broder - One of the best experts on this subject based on the ideXlab platform.

  • Resistance of Cynomolgus Monkeys to Nipah and Hendra Virus Disease Is Associated With Cell-Mediated and Humoral Immunity.
    The Journal of Infectious Diseases, 2019
    Co-Authors: Abhishek N. Prasad, Courtney Woolsey, Joan B. Geisbert, Krystle N. Agans, Viktoriya Borisevich, Daniel J. Deer, Chad E. Mire, Robert W. Cross, Karla A. Fenton, Christopher C Broder
    Abstract:

    Background The Henipaviruses, Hendra virus (HeV) and Nipah virus (NiV), are capable of causing severe and often lethal respiratory and/or neurologic disease in animals and humans. Given the sporadic nature of Henipavirus outbreaks, licensure of vaccines and therapeutics for human use will likely require demonstration of efficacy in animal models that faithfully reproduce the human condition. Currently, the African green monkey (AGM) best mimics human Henipavirus-induced disease. Methods The pathogenic potential of HeV and both strains of NiV (Malaysia, Bangladesh) was assessed in cynomolgus monkeys and compared with Henipavirus-infected historical control AGMs. Multiplex gene and protein expression assays were used to compare host responses. Results In contrast to AGMs, in which Henipaviruses cause severe and usually lethal disease, HeV and NiVs caused only mild or asymptomatic infections in macaques. All Henipaviruses replicated in macaques with similar kinetics as in AGMs. Infection in macaques was associated with activation and predicted recruitment of cytotoxic CD8+ T cells, Th1 cells, IgM+ B cells, and plasma cells. Conversely, fatal outcome in AGMs was associated with aberrant innate immune signaling, complement dysregulation, Th2 skewing, and increased secretion of MCP-1. Conclusion The restriction factors identified in macaques can be harnessed for development of effective countermeasures against Henipavirus disease.

  • Rescue and characterization of recombinant cedar virus, a non-pathogenic Henipavirus species.
    Virology Journal, 2018
    Co-Authors: Eric D Laing, Chanakha K Navaratnarajah, Linfa Wang, Moushimi Amaya, Yan Ru Feng, Roberto Cattaneo, Christopher C Broder
    Abstract:

    Hendra virus and Nipah virus are zoonotic viruses that have caused severe to fatal disease in livestock and human populations. The isolation of Cedar virus, a non-pathogenic virus species in the genus Henipavirus, closely-related to the highly pathogenic Hendra virus and Nipah virus offers an opportunity to investigate differences in pathogenesis and receptor tropism among these viruses. We constructed full-length cDNA clones of Cedar virus from synthetic oligonucleotides and rescued two replication-competent, recombinant Cedar virus variants: a recombinant wild-type Cedar virus and a recombinant Cedar virus that expresses a green fluorescent protein from an open reading frame inserted between the phosphoprotein and matrix genes. Replication kinetics of both viruses and stimulation of the interferon pathway were characterized in vitro. Cellular tropism for ephrin-B type ligands was qualitatively investigated by microscopy and quantitatively by a split-luciferase fusion assay. Successful rescue of recombinant Cedar virus expressing a green fluorescent protein did not significantly affect virus replication compared to the recombinant wild-type Cedar virus. We demonstrated that recombinant Cedar virus stimulated the interferon pathway and utilized the established Hendra virus and Nipah virus receptor, ephrin-B2, but not ephrin-B3 to mediate virus entry. We further characterized virus-mediated membrane fusion kinetics of Cedar virus with the known Henipavirus receptors ephrin-B2 and ephrin-B3. The recombinant Cedar virus platform may be utilized to characterize the determinants of pathogenesis across the Henipaviruses, investigate their receptor tropisms, and identify novel pan-Henipavirus antivirals. Moreover, these experiments can be conducted safely under BSL-2 conditions.

  • Rescue and characterization of recombinant cedar virus, a non-pathogenic Henipavirus species
    BMC, 2018
    Co-Authors: Eric D Laing, Chanakha K Navaratnarajah, Linfa Wang, Moushimi Amaya, Yan Ru Feng, Roberto Cattaneo, Christopher C Broder
    Abstract:

    Abstract Background Hendra virus and Nipah virus are zoonotic viruses that have caused severe to fatal disease in livestock and human populations. The isolation of Cedar virus, a non-pathogenic virus species in the genus Henipavirus, closely-related to the highly pathogenic Hendra virus and Nipah virus offers an opportunity to investigate differences in pathogenesis and receptor tropism among these viruses. Methods We constructed full-length cDNA clones of Cedar virus from synthetic oligonucleotides and rescued two replication-competent, recombinant Cedar virus variants: a recombinant wild-type Cedar virus and a recombinant Cedar virus that expresses a green fluorescent protein from an open reading frame inserted between the phosphoprotein and matrix genes. Replication kinetics of both viruses and stimulation of the interferon pathway were characterized in vitro. Cellular tropism for ephrin-B type ligands was qualitatively investigated by microscopy and quantitatively by a split-luciferase fusion assay. Results Successful rescue of recombinant Cedar virus expressing a green fluorescent protein did not significantly affect virus replication compared to the recombinant wild-type Cedar virus. We demonstrated that recombinant Cedar virus stimulated the interferon pathway and utilized the established Hendra virus and Nipah virus receptor, ephrin-B2, but not ephrin-B3 to mediate virus entry. We further characterized virus-mediated membrane fusion kinetics of Cedar virus with the known Henipavirus receptors ephrin-B2 and ephrin-B3. Conclusions The recombinant Cedar virus platform may be utilized to characterize the determinants of pathogenesis across the Henipaviruses, investigate their receptor tropisms, and identify novel pan-Henipavirus antivirals. Moreover, these experiments can be conducted safely under BSL-2 conditions

  • Passive Immunization and Active Vaccination against Hendra and Nipah Viruses
    Vaccines and Diagnostics for Transboundary Animal Diseases, 2013
    Co-Authors: Christopher C Broder
    Abstract:

    Hendra virus and Nipah virus are viral zoonoses first recognized in the mid and late 1990's and are now categorized as the type species of the genus Henipavirus within the family Paramyxoviridae. Their broad species tropism together with their capacity to cause severe and often fatal disease in both humans and animals make Hendra and Nipah “overlap agents” and significant biosecurity threats. The development of effective vaccination strategies to prevent or treat Henipavirus infection and disease has been an important area of research. Here, Henipavirus active and passive vaccination strategies that have been examined in animal challenge models of Hendra and Nipah virus disease are summarized and discussed.

  • Immunization Strategies Against Henipaviruses
    Current Topics in Microbiology and Immunology, 2012
    Co-Authors: Christopher C Broder, Dimitar B Nikolov, Linfa Wang, Thomas W. Geisbert, Deborah Middleton, Jackie Pallister, Katharine N. Bossart
    Abstract:

    Hendra virus and Nipah virus are recently discovered and closely related emerging viruses that now comprise the genus Henipavirus within the sub-family Paramyxoviridae and are distinguished by their broad species tropism and in addition to bats can infect and cause fatal disease in a wide variety of mammalian hosts including humans. The high mortality associated with human and animal Henipavirus infections has highlighted the importance and necessity of developing effective immunization strategies. The development of suitable animal models of Henipavirus infection and pathogenesis has been critical for testing the efficacy of potential therapeutic approaches. Several Henipavirus challenge models have been used and recent successes in both active and passive immunization strategies against Henipaviruses have been reported which have all targeted the viral envelope glycoproteins.

Branka Horvat - One of the best experts on this subject based on the ideXlab platform.

  • Understanding the interaction between Henipaviruses and their natural host, fruit bats: Paving the way toward control of highly lethal infection in humans.
    International Reviews of Immunology, 2017
    Co-Authors: François Enchéry, Branka Horvat
    Abstract:

    ABSTRACTHendra virus and Nipah virus (NiV) are highly pathogenic zoonotic paramyxoviruses, from Henipavirus genus, that have emerged in late 1990s in Australia and South-East Asia, respectively. Since their initial identification, numerous outbreaks have been reported, affecting both domestic animals and humans, and multiple rounds of person-to-person NiV transmission were observed. Widely distributed fruit bats from Pteropodidae family were found to be Henipavirus natural reservoir. Numerous studies have reported Henipavirus seropositivity in pteropid bats, including bats in Africa, thus expanding notably the geographic distribution of these viruses. Interestingly, Henipavirus infection in bats seems to be asymptomatic, in contrast to severe disease induced in numerous other mammals. Unique among the mammals by their ability to fly, these intriguing animals are natural reservoir for many other emerging and remerging viruses highly pathogenic for humans. This feature, combined with absence of clinical sym...

  • Understanding the interaction between Henipaviruses and their natural host, fruit bats: Paving the way toward control of highly lethal infection in humans
    International Reviews of Immunology, 2017
    Co-Authors: François Enchéry, Branka Horvat
    Abstract:

    Hendra virus and Nipah virus (NiV) are highly pathogenic zoonotic paramyxoviruses, from Henipavirus genus, that have emerged in late 1990s in Australia and South-East Asia, respectively. Since their initial identification, numerous outbreaks have been reported, affecting both domestic animals and humans, and multiple rounds of person-to-person NiV transmission were observed. Widely distributed fruit bats from Pteropodidae family were found to be Henipavirus natural reservoir. Numerous studies have reported Henipavirus seropositivity in pteropid bats, including bats in Africa, thus expanding notably the geographic distribution of these viruses. Interestingly, Henipavirus infection in bats seems to be asymptomatic, in contrast to severe disease induced in numerous other mammals. Unique among the mammals by their ability to fly, these intriguing animals are natural reservoir for many other emerging and remerging viruses highly pathogenic for humans. This feature, combined with absence of clinical symptoms, has attracted the interest of scientific community to virus-bat interactions. Therefore, several bat genomes were sequenced and particularities of the bat immune system have been intensively analyzed during the last decade to understand their coexistence with viruses in the absence of disease. The peculiarities in inflammasome activation, a constitutive expression of interferon alpha, and some differences in adaptive immunity have been recently reported in fruit bats. Studies on virus-bat interactions have thus emerged as an exciting novel area of research that should shed new light on the mechanisms that regulate viral infection and may allow development of novel therapeutic approaches to control this highly lethal emerging infectious disease in humans.

  • Heparan Sulfate-Dependent Enhancement of Henipavirus Infection
    Mbio, 2015
    Co-Authors: Cyrille Mathieu, Kévin P. Dhondt, Marie Châlons, Stéphane Mély, Hervé Raoul, François-loïc Cosset, Denis Gerlier, Romain R Vives, Didier Negre, Branka Horvat
    Abstract:

    ABSTRACT Nipah virus and Hendra virus are emerging, highly pathogenic, zoonotic paramyxoviruses that belong to the genus Henipavirus . They infect humans as well as numerous mammalian species. Both viruses use ephrin-B2 and -B3 as cell entry receptors, and following initial entry into an organism, they are capable of rapid spread throughout the host. We have previously reported that Nipah virus can use another attachment receptor, different from its entry receptors, to bind to nonpermissive circulating leukocytes, thereby promoting viral dissemination within the host. Here, this attachment molecule was identified as heparan sulfate for both Nipah virus and Hendra virus. Cells devoid of heparan sulfate were not able to mediate Henipavirus trans -infection and showed reduced permissivity to infection. Virus pseudotyped with Nipah virus glycoproteins bound heparan sulfate and heparin but no other glycosaminoglycans in a surface plasmon resonance assay. Furthermore, heparin was able to inhibit the interaction of the viruses with the heparan sulfate and to block cell-mediated trans -infection of Henipaviruses. Moreover, heparin was shown to bind to ephrin-B3 and to restrain infection of permissive cells in vitro . Consequently, treatment with heparin devoid of anticoagulant activity improved the survival of Nipah virus-infected hamsters. Altogether, these results reveal heparan sulfate as a new attachment receptor for Henipaviruses and as a potential therapeutic target for the development of novel approaches against these highly lethal infections. IMPORTANCE The Henipavirus genus includes two closely related, highly pathogenic paramyxoviruses, Nipah virus and Hendra virus, which cause elevated morbidity and mortality in animals and humans. Pathogenesis of both Nipah virus and Hendra virus infection is poorly understood, and efficient antiviral treatment is still missing. Here, we identified heparan sulfate as a novel attachment receptor used by both viruses to bind host cells. We demonstrate that heparin was able to inhibit the interaction of the viruses with heparan sulfate and to block cell-mediated trans -infection of Henipaviruses. Moreover, heparin also bound to the viral entry receptor and thereby restricted infection of permissive cells in vitro . Consequently, heparin treatment improved survival of Nipah virus-infected hamsters. These results uncover an important role of heparan sulfate in Henipavirus infection and open novel perspectives for the development of heparan sulfate-targeting therapeutic approaches for these emerging infections.

  • Heparan sulfate-dependent enhancement of Henipavirus infection.
    mBio, 2015
    Co-Authors: Cyrille Mathieu, Kévin P. Dhondt, Marie Châlons, Stéphane Mély, Hervé Raoul, François-loïc Cosset, Denis Gerlier, Romain R Vives, Didier Negre, Branka Horvat
    Abstract:

    Nipah virus and Hendra virus are emerging, highly pathogenic, zoonotic paramyxoviruses that belong to the genus Henipavirus. They infect humans as well as numerous mammalian species. Both viruses use ephrin-B2 and -B3 as cell entry receptors, and following initial entry into an organism, they are capable of rapid spread throughout the host. We have previously reported that Nipah virus can use another attachment receptor, different from its entry receptors, to bind to nonpermissive circulating leukocytes, thereby promoting viral dissemination within the host. Here, this attachment molecule was identified as heparan sulfate for both Nipah virus and Hendra virus. Cells devoid of heparan sulfate were not able to mediate Henipavirus trans-infection and showed reduced permissivity to infection. Virus pseudotyped with Nipah virus glycoproteins bound heparan sulfate and heparin but no other glycosaminoglycans in a surface plasmon resonance assay. Furthermore, heparin was able to inhibit the interaction of the viruses with the heparan sulfate and to block cell-mediated trans-infection of Henipaviruses. Moreover, heparin was shown to bind to ephrin-B3 and to restrain infection of permissive cells in vitro. Consequently, treatment with heparin devoid of anticoagulant activity improved the survival of Nipah virus-infected hamsters. Altogether, these results reveal heparan sulfate as a new attachment receptor for Henipaviruses and as a potential therapeutic target for the development of novel approaches against these highly lethal infections. The Henipavirus genus includes two closely related, highly pathogenic paramyxoviruses, Nipah virus and Hendra virus, which cause elevated morbidity and mortality in animals and humans. Pathogenesis of both Nipah virus and Hendra virus infection is poorly understood, and efficient antiviral treatment is still missing. Here, we identified heparan sulfate as a novel attachment receptor used by both viruses to bind host cells. We demonstrate that heparin was able to inhibit the interaction of the viruses with heparan sulfate and to block cell-mediated trans-infection of Henipaviruses. Moreover, heparin also bound to the viral entry receptor and thereby restricted infection of permissive cells in vitro. Consequently, heparin treatment improved survival of Nipah virus-infected hamsters. These results uncover an important role of heparan sulfate in Henipavirus infection and open novel perspectives for the development of heparan sulfate-targeting therapeutic approaches for these emerging infections.

  • Henipavirus pathogenesis and antiviral approaches
    Expert Review of Anti-infective Therapy, 2015
    Co-Authors: Cyrille Mathieu, Branka Horvat
    Abstract:

    Hendra virus and Nipah virus are closely related, recently emerged zoonotic paramyxoviruses, belonging to the Henipavirus genus. Both viruses induce generalized vasculitis affecting particularly the respiratory tract and CNS. The exceptionally broad species tropism of Henipavirus, the high case fatality rate and person-to-person transmission associated with Nipah virus outbreaks emphasize the necessity of effective antiviral strategies for these intriguing threatening pathogens. Current therapeutic approaches, validated in animal models, target early steps in viral infection; they include the use of neutralizing virus-specific antibodies and blocking membrane fusion with peptides that bind the viral fusion protein. A better understanding of Henipavirus pathogenesis is critical for the further advancement of antiviral treatment, and we summarize here the recent progress in the field.

Dimitar B Nikolov - One of the best experts on this subject based on the ideXlab platform.

  • structural and functional analyses reveal promiscuous and species specific use of ephrin receptors by cedar virus
    Proceedings of the National Academy of Sciences of the United States of America, 2019
    Co-Authors: Eric D Laing, Sofia Cheliout Da Silva, Stephanie R Petzing, Spencer L Sterling, Chanakha K Navaratnarajah, Linfa Wang, Glenn A. Marsh, Yan Xu, Moushimi Amaya, Dimitar B Nikolov
    Abstract:

    Cedar virus (CedV) is a bat-borne Henipavirus related to Nipah virus (NiV) and Hendra virus (HeV), zoonotic agents of fatal human disease. CedV receptor-binding protein (G) shares only ∼30% sequence identity with those of NiV and HeV, although they can all use ephrin-B2 as an entry receptor. We demonstrate that CedV also enters cells through additional B- and A-class ephrins (ephrin-B1, ephrin-A2, and ephrin-A5) and report the crystal structure of the CedV G ectodomain alone and in complex with ephrin-B1 or ephrin-B2. The CedV G receptor-binding site is structurally distinct from other Henipaviruses, underlying its capability to accommodate additional ephrin receptors. We also show that CedV can enter cells through mouse ephrin-A1 but not human ephrin-A1, which differ by 1 residue in the key contact region. This is evidence of species specific ephrin receptor usage by a Henipavirus, and implicates additional ephrin receptors in potential zoonotic transmission.

  • Immunization Strategies Against Henipaviruses
    Current Topics in Microbiology and Immunology, 2012
    Co-Authors: Christopher C Broder, Dimitar B Nikolov, Linfa Wang, Thomas W. Geisbert, Deborah Middleton, Jackie Pallister, Katharine N. Bossart
    Abstract:

    Hendra virus and Nipah virus are recently discovered and closely related emerging viruses that now comprise the genus Henipavirus within the sub-family Paramyxoviridae and are distinguished by their broad species tropism and in addition to bats can infect and cause fatal disease in a wide variety of mammalian hosts including humans. The high mortality associated with human and animal Henipavirus infections has highlighted the importance and necessity of developing effective immunization strategies. The development of suitable animal models of Henipavirus infection and pathogenesis has been critical for testing the efficacy of potential therapeutic approaches. Several Henipavirus challenge models have been used and recent successes in both active and passive immunization strategies against Henipaviruses have been reported which have all targeted the viral envelope glycoproteins.

  • Henipavirus mediated membrane fusion, virus entry and targeted therapeutics.
    Viruses, 2012
    Co-Authors: Deborah L. Steffen, Dimitar B Nikolov, Christopher C Broder
    Abstract:

    The Paramyxoviridae genus Henipavirus is presently represented by the type species Hendra and Nipah viruses which are both recently emerged zoonotic viral pathogens responsible for repeated outbreaks associated with high morbidity and mortality in Australia, Southeast Asia, India and Bangladesh. These enveloped viruses bind and enter host target cells through the coordinated activities of their attachment (G) and class I fusion (F) envelope glycoproteins. The Henipavirus G glycoprotein interacts with host cellular B class ephrins, triggering conformational alterations in G that lead to the activation of the F glycoprotein, which facilitates the membrane fusion process. Using the recently published structures of HeV-G and NiV-G and other paramyxovirus glycoproteins, we review the features of the Henipavirus envelope glycoproteins that appear essential for mediating the viral fusion process, including receptor binding, G-F interaction, F activation, with an emphasis on G and the mutations that disrupt viral infectivity. Finally, recent candidate therapeutics for Henipavirus-mediated disease are summarized in light of their ability to inhibit HeV and NiV entry by targeting their G and F glycoproteins.

  • Ephrin-B2 and ephrin-B3 as functional Henipavirus receptors
    Seminars in Cell & Developmental Biology, 2011
    Co-Authors: Kai Xu, Christopher C Broder, Dimitar B Nikolov
    Abstract:

    Abstract Members of the ephrin cell-surface protein family interact with the Eph receptors, the largest family of receptor tyrosine kinases, mediating bi-directional signaling during tumorogenesis and various developmental events. Surprisingly, ephrin-B2 and -B3 were recently identified as entry receptors for Henipaviruses, emerging zoonotic paramyxoviruses responsible for repeated outbreaks in humans and animals in Australia, Southeast Asia, India and Bangladesh. Nipah virus (NiV) and Hendra virus (HeV) are the only two identified members in the Henipavirus genus. While the initial human infection cases came from contact with infected pigs (NiV) or horses (HeV), in the more recent outbreaks of NiV both food-borne and human-to-human transmission were reported. These characteristics, together with high mortality and morbidity rates and lack of effective anti-viral therapies, make the Henipaviruses a potential biological-agent threat. Viral entry is an important target for the development of anti-viral drugs. The entry of Henipavirus is initiated by the attachment of the viral G envelope glycoprotein to the host cell receptors ephrin-B2 and/or -B3, followed by activation of the F fusion protein, which triggers fusion between the viral envelop and the host membrane. We review recent progress in the study of Henipavirus entry, particularly the identification of ephrins as their entry receptors, and the structural characterization of the ephrin/Henipa-G interactions.

  • Ephrin-B2 and ephrin-B3 as functional Henipavirus receptors
    Seminars in Cell & Developmental Biology, 2011
    Co-Authors: Kai Xu, Christopher C Broder, Dimitar B Nikolov
    Abstract:

    Abstract Members of the ephrin cell-surface protein family interact with the Eph receptors, the largest family of receptor tyrosine kinases, mediating bi-directional signaling during tumorogenesis and various developmental events. Surprisingly, ephrin-B2 and -B3 were recently identified as entry receptors for Henipaviruses, emerging zoonotic paramyxoviruses responsible for repeated outbreaks in humans and animals in Australia, Southeast Asia, India and Bangladesh. Nipah virus (NiV) and Hendra virus (HeV) are the only two identified members in the Henipavirus genus. While the initial human infection cases came from contact with infected pigs (NiV) or horses (HeV), in the more recent outbreaks of NiV both food-borne and human-to-human transmission were reported. These characteristics, together with high mortality and morbidity rates and lack of effective anti-viral therapies, make the Henipaviruses a potential biological-agent threat. Viral entry is an important target for the development of anti-viral drugs. The entry of Henipavirus is initiated by the attachment of the viral G envelope glycoprotein to the host cell receptors ephrin-B2 and/or -B3, followed by activation of the F fusion protein, which triggers fusion between the viral envelop and the host membrane. We review recent progress in the study of Henipavirus entry, particularly the identification of ephrins as their entry receptors, and the structural characterization of the ephrin/Henipa-G interactions.

Benhur Lee - One of the best experts on this subject based on the ideXlab platform.

  • Henipavirus: ecology, molecular virology, and pathogenesis.
    2012
    Co-Authors: Benhur Lee, Paul A. Rota
    Abstract:

    * Introduction: Nipah virus : discovery and Origin.- Ecological aspects of Hendra virus.- Epidemiology of Henipavirus disease in humans.- Molecular Virology of the Henipaviruses.- Henipavirus receptor usage and tropism.- Henipavirus membrane fusion and viral entry.- Clinical and pathological manufestations of human Henipavirus infection.- Henipaviruses in their natural animal hosts.- Nipah and Hendra virus interactions with the innate immune system.- Animal challenge models of Henipavirus infection and pathogenesis.- Diagnosis of Henipavirus infection: current capabilities and future directions.- immunization strategies against Henipaviruses.- Subject Index

  • Henipavirus receptor usage and tropism
    Current Topics in Microbiology and Immunology, 2012
    Co-Authors: Olivier Pernet, Yao E Wang, Benhur Lee
    Abstract:

    Nipah (NiV) and Hendra (HeV) viruses are the deadliest human pathogens within the Paramyxoviridae family, which include human and animal pathogens of global biomedical importance. NiV and HeV infections cause respiratory and encephalitic illness with high mortality rates in humans. Henipaviruses (HNV) are the only Paramyxoviruses classified as biosafety level 4 (BSL4) pathogens due to their extreme pathogenicity, potential for bioterrorism, and lack of licensed vaccines and therapeutics. HNV use ephrin-B2 and ephrin-B3, highly conserved proteins, as viral entry receptors. This likely accounts for their unusually broad species tropism, and also provides opportunities to study how receptor usage, cellular tropism, and end-organ pathology relates to the pathobiology of HNV infections. The clinical and pathologic manifestations of NiV and HeV virus infections are reviewed in the chapters by Wong et al. and Geisbert et al. in this issue. Here, we will review the biology of the HNV receptors, and how receptor usage relates to HNV cell tropism in vitro and in vivo.

  • Hendra and nipah infection: pathology, models and potential therapies.
    Infectious Disorders - Drug Targets, 2011
    Co-Authors: Frederic Vigant, Benhur Lee
    Abstract:

    The Paramyxoviridae family comprises of several genera that contain emerging or re-emerging threats for human and animal health with no real specific effective treatment available. Hendra and Nipah virus are members of a newly identified genus of emerging paramyxoviruses, Henipavirus. Since their discovery in the 1990s, Henipaviruses outbreaks have been associated with high economic and public health threat potential. When compared to other paramyxoviruses, Henipaviruses appear to have unique characteristics. Henipaviruses are zoonotic paramyxoviruses with a broader tropism than most other paramyxoviruses, and can cause severe acute encephalitis with unique features among viral encephalitides. There are currently no approved effective prophylactic or therapeutic treatments for Henipavirus infections. Although ribavirin was empirically used and seemed beneficial during the biggest outbreak caused by one of these viruses, the Nipah virus, its efficacy is disputed in light of its lack of efficacy in several animal models of Henipavirus infection. Nevertheless, because of its highly pathogenic nature, much effort has been spent in developing anti-Henipavirus therapeutics. In this review we describe the unique features of Henipavirus infections and the different strategies and animal models that have been developed so far in order to identify and test potential drugs to prevent or treat Henipavirus infections. Some of these components have the potential to be broad-spectrum antivirals as they target effectors of viral pathogenecity common to other viruses. We will focus on small molecules or biologics, rather than vaccine strategies, that have been developed as anti-henipaviral therapeutics.

  • A catalytically and genetically optimized β-lactamase-matrix based assay for sensitive, specific, and higher throughput analysis of native Henipavirus entry characteristics
    Virology Journal, 2009
    Co-Authors: Michael Wolf, Hector C. Aguilar, Yao Wang, Alexander N. Freiberg, Michael R. Holbrook, Benhur Lee
    Abstract:

    Nipah virus (NiV) and Hendra virus (HeV) are the only paramyxoviruses requiring Biosafety Level 4 (BSL-4) containment. Thus, study of Henipavirus entry at less than BSL-4 conditions necessitates the use of cell-cell fusion or pseudotyped reporter virus assays. Yet, these surrogate assays may not fully emulate the biological properties unique to the virus being studied. Thus, we developed a henipaviral entry assay based on a β-lactamase-Nipah Matrix (βla-M) fusion protein. We first codon-optimized the bacterial βla and the NiV-M genes to ensure efficient expression in mammalian cells. The βla-M construct was able to bud and form virus-like particles (VLPs) that morphologically resembled paramyxoviruses. βla-M efficiently incorporated both NiV and HeV fusion and attachment glycoproteins. Entry of these VLPs was detected by cytosolic delivery of βla-M, resulting in enzymatic and fluorescent conversion of the pre-loaded CCF2-AM substrate. Soluble Henipavirus receptors (ephrinB2) or antibodies against the F and/or G proteins blocked VLP entry. Additionally, a Y105W mutation engineered into the catalytic site of βla increased the sensitivity of our βla-M based infection assays by 2-fold. In toto, these methods will provide a more biologically relevant assay for studying Henipavirus entry at less than BSL-4 conditions.

  • Single amino acid changes in the Nipah and Hendra virus attachment glycoproteins distinguish ephrinB2 from ephrinB3 usage.
    Journal of Virology, 2007
    Co-Authors: Oscar A. Negrete, Hector C. Aguilar, David Chu, Benhur Lee
    Abstract:

    The Henipaviruses, Nipah virus (NiV) and Hendra virus (HeV), are lethal emerging paramyxoviruses. EphrinB2 and ephrinB3 have been identified as receptors for Henipavirus entry. NiV and HeV share similar cellular tropisms and likely use an identical receptor set, although a quantitative comparison of receptor usage by NiV and HeV has not been reported. Here we show that (i) soluble NiV attachment protein G (sNiV-G) bound to cell surface-expressed ephrinB3 with a 30-fold higher affinity than that of sHeV-G, (ii) NiV envelope pseudotyped reporter virus (NiVpp) entered ephrinB3-expressing cells much more efficiently than did HeV pseudotyped particles (HeVpp), and (iii) NiVpp but not HeVpp entry was inhibited efficiently by soluble ephrinB3. These data underscore the finding that NiV uses ephrinB3 more efficiently than does HeV. Henipavirus G chimeric protein analysis implicated residue 507 in the G ectodomain in efficient ephrinB3 usage. Curiously, alternative versions of published HeV-G sequences show variations at residue 507 that can clearly affect ephrinB3 but not ephrinB2 usage. We further defined surrounding mutations (W504A and E505A) that diminished ephrinB3-dependent binding and viral entry without compromising ephrinB2 receptor usage and another mutation (E533Q) that abrogated both ephrinB2 and -B3 usage. Our results suggest that ephrinB2 and -B3 binding determinants on Henipavirus G are distinct and dissociable. Global expression analysis showed that ephrinB3, but not ephrinB2, is expressed in the brain stem. Thus, ephrinB3-mediated viral entry and pathology may underlie the severe brain stem neuronal dysfunction seen in fatal Nipah viral encephalitis. Characterizing the determinants of ephrinB2 versus -B3 usage will further our understanding of Henipavirus pathogenesis.