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Siva Venkatesh IP, Majumdar A, Basu A. Prophylactic Administration of Gut Microbiome Metabolites Abrogated Microglial Activation and Subsequent Neuroinflammation in an Experimental Model of Japanese Encephalitis. ACS Chem Neurosci 2024; 15:1712-1727. [PMID: 38581382 DOI: 10.1021/acschemneuro.4c00028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/08/2024] Open
Abstract
Short-chain fatty acids (SCFAs) are gut microbial metabolic derivatives produced during the fermentation of ingested complex carbohydrates. SCFAs have been widely regarded to have a potent anti-inflammatory and neuro-protective role and have implications in several disease conditions, such as, inflammatory bowel disease, type-2 diabetes, and neurodegenerative disorders. Japanese encephalitis virus (JEV), a neurotropic flavivirus, is associated with life threatening neuro-inflammation and neurological sequelae in infected hosts. In this study, we hypothesize that SCFAs have potential in mitigating JEV pathogenesis. Postnatal day 10 BALB/c mice were intraperitoneally injected with either a SCFA mixture (acetate, propionate, and butyrate) or PBS for a period of 7 days, followed by JEV infection. All mice were observed for onset and progression of symptoms. The brain tissue was collected upon reaching terminal illness for further analysis. SCFA-supplemented JEV-infected mice (SCFA + JEV) showed a delayed onset of symptoms, lower hindlimb clasping score, and decreased weight loss and increased survival by 3 days (p < 0.0001) upon infection as opposed to the PBS-treated JEV-infected animals (JEV). Significant downregulation of inflammatory cytokines TNF-α, MCP-1, IL-6, and IFN-Υ in the SCFA + JEV group relative to the JEV-infected control group was observed. Inflammatory mediators, phospho-NF-kB (P-NF-kB) and iba1, showed 2.08 ± 0.1 and 3.132 ± 0.43-fold upregulation in JEV versus 1.19 ± 0.11 and 1.31 ± 0.11-fold in the SCFA + JEV group, respectively. Tissue section analysis exhibited reduced glial activation (JEV group─42 ± 2.15 microglia/ROI; SCFA + JEV group─27.07 ± 1.8 microglia/ROI) in animals that received SCFA supplementation prior to infection as seen from the astrocytic and microglial morphometric analysis. Caspase-3 immunoblotting showed 4.08 ± 1.3-fold upregulation in JEV as compared to 1.03 ± 0.14-fold in the SCFA + JEV group and TUNEL assay showed a reduced cellular death post-JEV infection (JEV-6.4 ± 1.5 cells/ROI and SCFA + JEV-3.7 ± 0.73 cells/ROI). Our study critically contributes to the increasing evidence in support of SCFAs as an anti-inflammatory and neuro-protective agent, we further expand its scope as a potential supplementary intervention in JEV-mediated neuroinflammation.
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MESH Headings
- Gastrointestinal Microbiome/physiology
- Neuroinflammatory Diseases/drug therapy
- Neuroinflammatory Diseases/immunology
- Neuroinflammatory Diseases/metabolism
- Neuroinflammatory Diseases/microbiology
- Microglia/drug effects
- Microglia/immunology
- Encephalitis, Japanese/drug therapy
- Encephalitis, Japanese/immunology
- Encephalitis, Japanese/microbiology
- Encephalitis, Japanese/prevention & control
- Encephalitis, Japanese/virology
- Fatty Acids, Volatile/pharmacology
- Fatty Acids, Volatile/therapeutic use
- Encephalitis Viruses, Japanese/drug effects
- Encephalitis Viruses, Japanese/immunology
- Encephalitis Viruses, Japanese/pathogenicity
- Survival Analysis
- Chemokines/immunology
- Chemokines/metabolism
- Inflammation Mediators/immunology
- Inflammation Mediators/metabolism
- Cytokine Release Syndrome/immunology
- Cytokine Release Syndrome/metabolism
- Cytokine Release Syndrome/prevention & control
- Humans
- Female
- Animals
- Mice
- Apoptosis/drug effects
- Brain/drug effects
- Brain/metabolism
- Brain/virology
- Viral Load/drug effects
- Time Factors
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Affiliation(s)
| | - Atreye Majumdar
- National Brain Research Centre, Manesar, Haryana 122052, India
| | - Anirban Basu
- National Brain Research Centre, Manesar, Haryana 122052, India
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Westlake D, Bielefeldt-Ohmann H, Prow NA, Hall RA. Novel Flavivirus Attenuation Markers Identified in the Envelope Protein of Alfuy Virus. Viruses 2021; 13:v13020147. [PMID: 33498300 PMCID: PMC7909262 DOI: 10.3390/v13020147] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Revised: 01/12/2021] [Accepted: 01/14/2021] [Indexed: 11/16/2022] Open
Abstract
Alfuy (ALFV) is an attenuated flavivirus related to the Murray Valley encephalitis virus (MVEV). We previously identified markers of attenuation in the envelope (E) protein of the prototype strain (ALFV3929), including the hinge region (E273-277) and lack of glycosylation at E154-156. To further determine the mechanisms of attenuation we assessed ALFV3929 binding to glycosaminoglycans (GAG), a known mechanism of flaviviruses attenuation. Indeed, ALFV3929 exhibited reduced binding to GAG-rich cells in the presence of heparin; however, low-passage ALFV isolates were relatively unaffected. Sequence comparisons between ALFV strains and structural modelling incriminated a positively-charged residue (K327) in ALFV3929 as a GAG-binding motif. Substitution of this residue to the corresponding uncharged residue in MVEV (L), using a previously described chimeric virus containing the prM & E genes of ALFV3929 in the backbone of MVEV (MVEV/ALFV-prME), confirmed a role for K327 in enhanced GAG binding. When the wild type residues at E327, E273-277 and E154-156 of ALFV3929 were replaced with the corresponding residues from virulent MVEV, it revealed each motif contributed to attenuation of ALFV3929, with the E327/E273-277 combination most dominant. These data demonstrate that attenuation of ALFV3929 is multifactorial and provide new insights for the rational design of attenuated flavivirus vaccines.
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Affiliation(s)
- Daniel Westlake
- School of Chemistry and Molecular Biosciences, The University of Queensland, St. Lucia, QLD 4072, Australia; (D.W.); (H.B.-O.)
| | - Helle Bielefeldt-Ohmann
- School of Chemistry and Molecular Biosciences, The University of Queensland, St. Lucia, QLD 4072, Australia; (D.W.); (H.B.-O.)
- Australian Infectious Diseases Research Centre, The University of Queensland, St. Lucia, QLD 4072, Australia
- School of Veterinary Sciences, The University of Queensland, St. Lucia, QLD 4072, Australia
| | - Natalie A. Prow
- School of Chemistry and Molecular Biosciences, The University of Queensland, St. Lucia, QLD 4072, Australia; (D.W.); (H.B.-O.)
- Australian Infectious Diseases Research Centre, The University of Queensland, St. Lucia, QLD 4072, Australia
- Experimental Therapeutics Laboratory, School of Clinical and Health Sciences, University of South Australia Cancer Research Institute, Adelaide, SA 5000, Australia
- Correspondence: (N.A.P.); (R.A.H.)
| | - Roy A. Hall
- School of Chemistry and Molecular Biosciences, The University of Queensland, St. Lucia, QLD 4072, Australia; (D.W.); (H.B.-O.)
- Australian Infectious Diseases Research Centre, The University of Queensland, St. Lucia, QLD 4072, Australia
- Correspondence: (N.A.P.); (R.A.H.)
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3
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Singh PK, Khatri I, Jha A, Pretto CD, Spindler KR, Arumugaswami V, Giri S, Kumar A, Bhasin MK. Determination of system level alterations in host transcriptome due to Zika virus (ZIKV) Infection in retinal pigment epithelium. Sci Rep 2018; 8:11209. [PMID: 30046058 PMCID: PMC6060127 DOI: 10.1038/s41598-018-29329-2] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2017] [Accepted: 07/10/2018] [Indexed: 12/26/2022] Open
Abstract
Previously, we reported that Zika virus (ZIKV) causes ocular complications such as chorioretinal atrophy, by infecting cells lining the blood-retinal barrier, including the retinal pigment epithelium (RPE). To understand the molecular basis of ZIKV-induced retinal pathology, we performed a meta-analysis of transcriptome profiles of ZIKV-infected human primary RPE and other cell types infected with either ZIKV or other related flaviviruses (Japanese encephalitis, West Nile, and Dengue). This led to identification of a unique ZIKV infection signature comprising 43 genes (35 upregulated and 8 downregulated). The major biological processes perturbed include SH3/SH2 adaptor activity, lipid and ceramide metabolism, and embryonic organ development. Further, a comparative analysis of some differentially regulated genes (ABCG1, SH2B3, SIX4, and TNFSF13B) revealed that ZIKV induced their expression relatively more than dengue virus did in RPE. Importantly, the pharmacological inhibition of ABCG1, a membrane transporter of cholesterol, resulted in reduced ZIKV infectivity. Interestingly, the ZIKV infection signature revealed the downregulation of ALDH5A1 and CHML, genes implicated in neurological (cognitive impairment, expressive language deficit, and mild ataxia) and ophthalmic (choroideremia) disorders, respectively. Collectively, our study revealed that ZIKV induces differential gene expression in RPE cells, and the identified genes/pathways (e.g., ABCG1) could potentially contribute to ZIKV-associated ocular pathologies.
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Affiliation(s)
- Pawan Kumar Singh
- Department of Ophthalmology, Visual and Anatomical Sciences, Wayne State University, Detroit, MI, USA
| | - Indu Khatri
- BIDMC Genomics, Proteomics, Bioinformatics and Systems Biology Centre, Beth Israel Deaconess Medical Center, Boston, MA, USA
- Division of Interdisciplinary Medicine and Biotechnology, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Alokkumar Jha
- BIDMC Genomics, Proteomics, Bioinformatics and Systems Biology Centre, Beth Israel Deaconess Medical Center, Boston, MA, USA
- Division of Interdisciplinary Medicine and Biotechnology, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Carla D Pretto
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, MI, USA
| | - Katherine R Spindler
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, MI, USA
| | | | - Shailendra Giri
- Department of Neurology, Henry Ford Health System, Detroit, MI, USA
| | - Ashok Kumar
- Department of Ophthalmology, Visual and Anatomical Sciences, Wayne State University, Detroit, MI, USA.
- Department of Biochemistry, Microbiology, and Immunology, Wayne State University, Detroit, MI, USA.
| | - Manoj K Bhasin
- BIDMC Genomics, Proteomics, Bioinformatics and Systems Biology Centre, Beth Israel Deaconess Medical Center, Boston, MA, USA.
- Division of Interdisciplinary Medicine and Biotechnology, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA.
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Blázquez AB, Escribano-Romero E, Martín-Acebes MA, Petrovic T, Saiz JC. Limited susceptibility of mice to Usutu virus (USUV) infection and induction of flavivirus cross-protective immunity. Virology 2015; 482:67-71. [PMID: 25827530 DOI: 10.1016/j.virol.2015.03.020] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2015] [Revised: 02/17/2015] [Accepted: 03/05/2015] [Indexed: 01/22/2023]
Abstract
Flaviviruses are RNA viruses that constitute a worrisome threat to global human and animal health. In Europe, West Nile virus (WNV) outbreaks have dramatically increased in number and severity in recent years, with dozens of human and horse deaths and a high avian mortality across the continent. Besides WNV, the only clinically relevant mosquito-borne flavivirus detected so far in Europe has been the Usutu virus (USUV), which after being reported for the first time in Austria in 2001, quickly spread across Europe, causing a considerable number of bird deaths and neurological disorders in a few immunocompromised patients. Even though USUV infects multiple avian species that develop antibodies, there is little information about USUV susceptibility, pathogenicity and cross-reactive immunity. Here, the susceptibility of suckling and adult mice to USUV infection and the induction of cross-protective immunity against WNV challenge have been addressed.
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Affiliation(s)
- Ana-Belén Blázquez
- Departamento de Biotecnología. Ctra. Coruña Km. 7.5, 28040 Madrid, Spain
| | | | | | - Tamas Petrovic
- Scientific Veterinary Institute "Novi Sad", Novi Sad, Serbia
| | - Juan-Carlos Saiz
- Departamento de Biotecnología. Ctra. Coruña Km. 7.5, 28040 Madrid, Spain.
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Becker N, Jöst H, Ziegler U, Eiden M, Höper D, Emmerich P, Fichet-Calvet E, Ehichioya DU, Czajka C, Gabriel M, Hoffmann B, Beer M, Tenner-Racz K, Racz P, Günther S, Wink M, Bosch S, Konrad A, Pfeffer M, Groschup MH, Schmidt-Chanasit J. Epizootic emergence of Usutu virus in wild and captive birds in Germany. PLoS One 2012; 7:e32604. [PMID: 22389712 PMCID: PMC3289667 DOI: 10.1371/journal.pone.0032604] [Citation(s) in RCA: 113] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2011] [Accepted: 01/27/2012] [Indexed: 11/20/2022] Open
Abstract
This study aimed to identify the causative agent of mass mortality in wild and captive birds in southwest Germany and to gather insights into the phylogenetic relationship and spatial distribution of the pathogen. Since June 2011, 223 dead birds were collected and tested for the presence of viral pathogens. Usutu virus (USUV) RNA was detected by real-time RT-PCR in 86 birds representing 6 species. The virus was isolated in cell culture from the heart of 18 Blackbirds (Turdus merula). USUV-specific antigen was demonstrated by immunohistochemistry in brain, heart, liver, and lung of infected Blackbirds. The complete polyprotein coding sequence was obtained by deep sequencing of liver and spleen samples of a dead Blackbird from Mannheim (BH65/11-02-03). Phylogenetic analysis of the German USUV strain BH65/11-02-03 revealed a close relationship with strain Vienna that caused mass mortality among birds in Austria in 2001. Wild birds from lowland river valleys in southwest Germany were mainly affected by USUV, but also birds kept in aviaries. Our data suggest that after the initial detection of USUV in German mosquitoes in 2010, the virus spread in 2011 and caused epizootics among wild and captive birds in southwest Germany. The data also indicate an increased risk of USUV infections in humans in Germany.
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Affiliation(s)
- Norbert Becker
- German Mosquito Control Association (KABS), Waldsee, Germany
- Department of Zoology, Heidelberg University, Heidelberg, Germany
| | - Hanna Jöst
- German Mosquito Control Association (KABS), Waldsee, Germany
- Department of Zoology, Heidelberg University, Heidelberg, Germany
- Department of Virology, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Ute Ziegler
- Institute for Novel and Emerging Infectious Diseases, Friedrich-Loeffler-Institut, Greifswald, Germany
| | - Martin Eiden
- Institute for Novel and Emerging Infectious Diseases, Friedrich-Loeffler-Institut, Greifswald, Germany
| | - Dirk Höper
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, Greifswald, Germany
| | - Petra Emmerich
- Department of Virology, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | | | - Deborah U. Ehichioya
- Department of Virology, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Christina Czajka
- German Mosquito Control Association (KABS), Waldsee, Germany
- Department of Zoology, Heidelberg University, Heidelberg, Germany
- Department of Virology, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Martin Gabriel
- Department of Virology, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Bernd Hoffmann
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, Greifswald, Germany
| | - Martin Beer
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, Greifswald, Germany
| | - Klara Tenner-Racz
- Department of Pathology, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Paul Racz
- Department of Pathology, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Stephan Günther
- Department of Virology, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Michael Wink
- Institute of Pharmacy and Molecular Biotechnology, Heidelberg University, Heidelberg, Germany
| | - Stefan Bosch
- Nature and Biodiversity Conservation Union (NABU) Baden-Württemberg, Stuttgart, Germany
| | - Armin Konrad
- Avifauna-Nordbaden.de, Ornithologische Gesellschaft Baden-Württemberg (OGBW)-Nordbaden, Heidelberg, Germany
| | - Martin Pfeffer
- Institute of Animal Hygiene and Veterinary Public Health, Faculty of Veterinary Medicine, University of Leipzig, Leipzig, Germany
| | - Martin H. Groschup
- Institute for Novel and Emerging Infectious Diseases, Friedrich-Loeffler-Institut, Greifswald, Germany
| | - Jonas Schmidt-Chanasit
- Department of Virology, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
- * E-mail:
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Wu HH, Chen CT, Lin YL, Lee ST. Sub-fragments of the envelope gene are highly protective against the Japanese encephalitis virus lethal infection in DNA priming—protein boosting immunization strategies. Vaccine 2004; 22:793-800. [PMID: 14741175 DOI: 10.1016/j.vaccine.2003.02.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The envelope (E) gene of Japanese encephalitis virus (JEV) plays a major protective role against JEV infection. In order to locate the part of E gene that is responsible for this protection, an N-terminal fragment EA (nucleotide number 933-1877 bp of JEV genome) and a C-terminal fragment EB (nucleotide number 1851-2330 bp of JEV genome) from E gene were prepared. Both of these fragments were used in the form of recombinant proteins (rEA and rEB) and plasmid DNA (pEA, pM15EA and pEB) for immunizations. Recombinant EA protein (rEA) was previously found to be non-protective because it was expressed in an insoluble form. Plasmid EA (pEA) was also found to be non-protective unless it is preceded by a 15 mer signal peptide derived from the very C-terminal of the membrane gene (M) of JEV to form pM15EA plasmid indicating the importance of the signal peptide in the expression of EA immunogenicity. Although pM15EA and pEB are both immunogenic and protective against JEV lethal infection, the protection by both fragments however is not optimal. Even when pM15EA and pEB were used together for immunization, maximum protection as those induced by control vaccine was not achieved. However, if individual fragments (EA or EB) were used in a DNA priming-protein boosting or protein priming-DNA boosting strategy, high levels of protection were achieved by both fragments. This was especially true for EA fragment where the level of protection against JEV lethal infection was equal to that induced by commercially available vaccine alone. The protection correlated very well with the neutralizing antibody titers and the T helper cell involved in this process in mainly the Th1 type.
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MESH Headings
- Animals
- Antibodies, Viral/analysis
- Antibodies, Viral/biosynthesis
- Cloning, Molecular
- Dose-Response Relationship, Drug
- Encephalitis Viruses, Japanese/immunology
- Encephalitis Viruses, Japanese/pathogenicity
- Encephalitis, Japanese/immunology
- Encephalitis, Japanese/prevention & control
- Escherichia coli/genetics
- Escherichia coli/immunology
- Female
- Genes, Viral/genetics
- Genes, Viral/immunology
- Immunization
- Immunization, Secondary
- Japanese Encephalitis Vaccines/genetics
- Japanese Encephalitis Vaccines/immunology
- Mice
- Mice, Inbred C3H
- Neutralization Tests
- Plasmids/genetics
- Plasmids/immunology
- Vaccines, DNA/genetics
- Vaccines, DNA/immunology
- Viral Envelope Proteins/genetics
- Viral Envelope Proteins/immunology
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Affiliation(s)
- Hsued Hwa Wu
- Division of Infectious Diseases, Institute of Biomedical Sciences, Academia Sinica, Taipei 11529, Taiwan, ROC
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Saul A. Zooprophylaxis or zoopotentiation: the outcome of introducing animals on vector transmission is highly dependent on the mosquito mortality while searching. Malar J 2003; 2:32. [PMID: 14565850 PMCID: PMC222927 DOI: 10.1186/1475-2875-2-32] [Citation(s) in RCA: 130] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2003] [Accepted: 09/19/2003] [Indexed: 11/10/2022] Open
Abstract
Background Zooprophylaxis, the diversion of disease carrying insects from humans to animals, may reduce transmission of diseases such as malaria. However, as the number of animals increases, improved availability of blood meals may increase mosquito survival, thereby countering the impact of diverting feeds. Methods Computer simulation was used to examine the effects of animals on the transmission of human diseases by mosquitoes. Three scenarios were modelled: (1) endemic transmission, where the animals cannot be infected, eg. malaria; (2) epidemic transmission, where the animals cannot be infected but humans remain susceptible, e.g. malaria; (3) epidemic disease, where both humans and animals can be infected, but develop sterile immunity, eg. Japanese encephalitis B. For each, the passive impact of animals as well as the use of animals as bait to attract mosquitoes to insecticide was examined. The computer programmes are available from the author. A teaching model accompanies this article. Results For endemic and epidemic malaria with significant searching-associated vector mortality, changing animal numbers and accessibility had little impact. Changing the accessibility of the humans had a much greater effect. For diseases with an animal amplification cycle, the most critical factor was the proximity of the animals to the mosquito breeding sites. Conclusion Estimates of searching-associated vector mortality are essential before the effects of changing animal husbandry practices can be predicted. With realistic values of searching-associated vector mortality rates, zooprophylaxis may be ineffective. However, use of animals as bait to attract mosquitoes to insecticide is predicted to be a promising strategy.
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Affiliation(s)
- Allan Saul
- Malaria Vaccine Development Unit, NIAID, NIH, Rockville, MD 20852, USA.
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Affiliation(s)
- J S Mackenzie
- Department of Microbiology and Parasitology, University of Queensland, Brisbane, Queensland 4072, Australia
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9
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Abstract
Infectious clone methodology is a valuable tool of modern experimental virology. However, its use is often constrained by the instability of infectious clone constructs during propagation in E. coli. To circumvent this problem, we have devised a strategy that could be suitable for design of +RNA virus molecular clones in general. An infectious clone is assembled as "infectious DNA," and expression of problem regions present in the viral cDNA is prevented during propagation in E. coli by insertion of short introns. To demonstrate the feasibility of this approach, a highly unstable Japanese encephalitis flavivirus infectious clone has been successfully converted into a remarkably stable infectious DNA construct with the specific infectivity of 10(6) pfu/microg in cell culture. The proposed strategy may be useful in the design of self-amplifying gene therapy vectors and development of new immunization methodologies, and could facilitate creation of molecular repositories of existing viral vaccines.
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Affiliation(s)
- V Yamshchikov
- Department of Internal Medicine, University of Virginia, Charlottesville, Virginia 22908, USA.
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MESH Headings
- Animals
- Australia/epidemiology
- Biological Evolution
- Culicidae/virology
- Encephalitis Virus, Murray Valley/isolation & purification
- Encephalitis Virus, Murray Valley/pathogenicity
- Encephalitis Viruses, Japanese/classification
- Encephalitis Viruses, Japanese/genetics
- Encephalitis Viruses, Japanese/isolation & purification
- Encephalitis Viruses, Japanese/pathogenicity
- Encephalitis, Arbovirus/epidemiology
- Encephalitis, Arbovirus/prevention & control
- Encephalitis, Arbovirus/veterinary
- Encephalitis, Arbovirus/virology
- Genome, Viral
- Glycosylation
- Humans
- Sentinel Surveillance
- Seroepidemiologic Studies
- Viral Vaccines
- Virulence
- West Nile Fever/epidemiology
- West Nile Fever/virology
- West Nile virus/classification
- West Nile virus/genetics
- West Nile virus/isolation & purification
- West Nile virus/pathogenicity
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Affiliation(s)
- R A Hall
- Department of Microbiology and Parasitology, The University of Queensland, Brisbane, Australia.
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Park JS, Yang JM, Min MK. Hepatitis C virus nonstructural protein NS4B transforms NIH3T3 cells in cooperation with the Ha-ras oncogene. Biochem Biophys Res Commun 2000; 267:581-7. [PMID: 10631105 DOI: 10.1006/bbrc.1999.1999] [Citation(s) in RCA: 70] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Although the mechanism of carcinogenesis by hepatitis C virus (HCV) is not clearly known, core and NS3P protein have been shown to form tumors in specific cell lines. In this study, on the basis of the fact that the core and NS4B proteins of Kunjin virus translocate into the nucleus, we were prompted to investigate whether the HCV nonstructural protein NS4B has any function in tumor formation. First, we examined the location of the NS4B protein of HCV in transfected cells and then its oncogenic activity by transfection of NIH3T3 cells with the NS4B gene in the presence or absence of the Ha-ras gene. The NS4B protein was present only in the cytoplasm, particularly in the perinuclear region, different from the case of the Kunjun virus. The cells expressing HCV NS4B cooperatively with the Ha-ras gene showed loss of contact inhibition, morphological alterations, and anchorage-independent growth. These biological activities were confirmed by the transcription activation of the reporter gene from the AP1 promoter, by the NS4B protein in association with Ha-ras. Our results demonstrated that HCV NS4B protein in association with the Ha-ras gene played an important role in the malignant transformation of cells by HCV.
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Affiliation(s)
- J S Park
- Mogam Biotechnology Research Institute, 341 Pojung-Ri, Koosung-Myon, Yongin-City, Kyunggi-Do, 449-910, Korea
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12
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Hall RA, Khromykh AA, Mackenzie JM, Scherret JH, Khromykh TI, Mackenzie JS. Loss of dimerisation of the nonstructural protein NS1 of Kunjin virus delays viral replication and reduces virulence in mice, but still allows secretion of NS1. Virology 1999; 264:66-75. [PMID: 10544130 DOI: 10.1006/viro.1999.9956] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The flavivirus nonstructural protein NS1 has been implicated in viral RNA replication, although its precise role has not been identified. In its native state NS1 exists as a heat labile homodimer that is thought to be required for NS1 function and secretion. However, we have recently identified a cDNA clone of KUN virus (FLSD) that replicates efficiently in cell culture but produces and secretes NS1 in monomeric form. Sequence analysis of the NS1 gene in FLSD revealed a single amino acid substitution (proline(250) to leucine) when compared with the parental KUN virus. When site-directed mutagenesis was used to substitute leucine(250) with proline in FLSD to produce the clone 250pro, dimerisation was fully restored. Furthermore, time course experiments revealed that 250pro replicated in Vero cells significantly faster than FLSD and produced 100-fold more infectious virus early (12-24 h) in infection. This correlated with our observations that FLSD required approximately 10-fold more infectious virus than 250pro to produce disease in weanling mice after intraperitoneal inoculation. Taken together our results indicate that mutation from proline to leucine at residue 250 in KUN NS1 ablates dimer formation, slows virus replication, and reduces virulence in mice.
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Affiliation(s)
- R A Hall
- Department of Microbiology, University of Queensland, Brisbane, Queensland, 4072, Australia.
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Abstract
Completion of the Kunjin virus (KUN) RNA sequence showed that it is the longest flavivirus sequence reported (11,022 bases), commencing with a 5' noncoding region of 96 bases. The 3' noncoding sequence of 624 nucleotides included a unique insertion sequence of 46 bases adjacent to the stop codon, but otherwise it had properties similar to those of RNAs of closely related flaviviruses. A full-length KUN cDNA clone which could be stably propagated in Escherichia coli DH5 alpha was constructed; SP6 polymerase RNA transcripts from amplified cDNA were infectious when transfected into BHK-21 cells. A mutational change abolishing the BamHI restriction site at position 4049, leading to a conservative amino acid change of Arg-175 to Lys in the NS2A protein, was introduced into the cDNA during construction and was retained in the recovered virus. Extra terminal nucleotides introduced during cloning of the cDNA were shown to be present in the in vitro RNA transcripts but absent in the RNA of recovered virus. Although recovered virus differed from the parental KUN by a smaller plaque phenotype and delayed growth rate in BHK-21 cells and mice, it was very similar as assessed by several other criteria, such as peak titer during growth in cells, infectivity titer in cells and in mice, rate of adsorption and penetration in cells, replication at 39 degrees C, and neurovirulence after intraperitoneal injection in mice. The KUN stably cloned cDNA will provide a useful basis for future studies in defining and characterizing functional roles of all the gene products.
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MESH Headings
- Animals
- Base Sequence
- Cells, Cultured
- Cloning, Molecular
- Cricetinae
- DNA, Complementary
- DNA, Viral/genetics
- Encephalitis Viruses, Japanese/genetics
- Encephalitis Viruses, Japanese/isolation & purification
- Encephalitis Viruses, Japanese/pathogenicity
- Escherichia coli/genetics
- Mice
- Mice, Inbred BALB C
- Molecular Sequence Data
- Plasmids
- RNA, Messenger/genetics
- RNA, Messenger/isolation & purification
- RNA, Viral/genetics
- RNA, Viral/isolation & purification
- Sequence Homology, Nucleic Acid
- Vero Cells
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Affiliation(s)
- A A Khromykh
- Sir Albert Sakzewski Virus Research Centre, Royal Childrens Hospital, Brisbane, Australia
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