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Loterio RK, Monson EA, Templin R, de Bruyne JT, Flores HA, Mackenzie JM, Ramm G, Helbig KJ, Simmons CP, Fraser JE. Antiviral Wolbachia strains associate with Aedes aegypti endoplasmic reticulum membranes and induce lipid droplet formation to restrict dengue virus replication. mBio 2024; 15:e0249523. [PMID: 38132636 PMCID: PMC10865983 DOI: 10.1128/mbio.02495-23] [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] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2023] [Accepted: 11/20/2023] [Indexed: 12/23/2023] Open
Abstract
Wolbachia are a genus of insect endosymbiotic bacteria which includes strains wMel and wAlbB that are being utilized as a biocontrol tool to reduce the incidence of Aedes aegypti-transmitted viral diseases like dengue. However, the precise mechanisms underpinning the antiviral activity of these Wolbachia strains are not well defined. Here, we generated a panel of Ae. aegypti-derived cell lines infected with antiviral strains wMel and wAlbB or the non-antiviral Wolbachia strain wPip to understand host cell morphological changes specifically induced by antiviral strains. Antiviral strains were frequently found to be entirely wrapped by the host endoplasmic reticulum (ER) membrane, while wPip bacteria clustered separately in the host cell cytoplasm. ER-derived lipid droplets (LDs) increased in volume in wMel- and wAlbB-infected cell lines and mosquito tissues compared to cells infected with wPip or Wolbachia-free controls. Inhibition of fatty acid synthase (required for triacylglycerol biosynthesis) reduced LD formation and significantly restored ER-associated dengue virus replication in cells occupied by wMel. Together, this suggests that antiviral Wolbachia strains may specifically alter the lipid composition of the ER to preclude the establishment of dengue virus (DENV) replication complexes. Defining Wolbachia's antiviral mechanisms will support the application and longevity of this effective biocontrol tool that is already being used at scale.IMPORTANCEAedes aegypti transmits a range of important human pathogenic viruses like dengue. However, infection of Ae. aegypti with the insect endosymbiotic bacterium, Wolbachia, reduces the risk of mosquito to human viral transmission. Wolbachia is being utilized at field sites across more than 13 countries to reduce the incidence of viruses like dengue, but it is not well understood how Wolbachia induces its antiviral effects. To examine this at the subcellular level, we compared how different strains of Wolbachia with varying antiviral strengths associate with and modify host cell structures. Strongly antiviral strains were found to specifically associate with the host endoplasmic reticulum and induce striking impacts on host cell lipid droplets. Inhibiting Wolbachia-induced lipid redistribution partially restored dengue virus replication demonstrating this is a contributing role for Wolbachia's antiviral activity. These findings provide new insights into how antiviral Wolbachia strains associate with and modify Ae. aegypti host cells.
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Affiliation(s)
- Robson K. Loterio
- Department of Microbiology, Biomedicine Discovery Institute, Monash University, Clayton, Australia
| | - Ebony A. Monson
- Department of Microbiology, Anatomy, Physiology and Pharmacology; School of Agriculture, Biomedicine and Environment, La Trobe University, Melbourne, Australia
| | - Rachel Templin
- Ramaciotti Centre For Cryo-Electron Microscopy, Monash University, Clayton, Australia
| | | | - Heather A. Flores
- School of Biological Sciences, Monash University, Clayton, Australia
| | - Jason M. Mackenzie
- Department of Microbiology and Immunology, University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, Australia
| | - Georg Ramm
- Ramaciotti Centre For Cryo-Electron Microscopy, Monash University, Clayton, Australia
| | - Karla J. Helbig
- Department of Microbiology, Anatomy, Physiology and Pharmacology; School of Agriculture, Biomedicine and Environment, La Trobe University, Melbourne, Australia
| | - Cameron P. Simmons
- Department of Microbiology, Biomedicine Discovery Institute, Monash University, Clayton, Australia
- World Mosquito Program, Monash University, Clayton, Australia
| | - Johanna E. Fraser
- Department of Microbiology, Biomedicine Discovery Institute, Monash University, Clayton, Australia
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Allman MJ, Lin YH, Joubert DA, Addley-Cook J, Mejía-Torres MC, Simmons CP, Flores HA, Fraser JE. Enhancing the scalability of Wolbachia-based vector-borne disease management: time and temperature limits for storage and transport of Wolbachia-infected Aedes aegypti eggs for field releases. Parasit Vectors 2023; 16:108. [PMID: 36934294 PMCID: PMC10024388 DOI: 10.1186/s13071-023-05724-1] [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] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2023] [Accepted: 03/02/2023] [Indexed: 03/20/2023] Open
Abstract
BACKGROUND Introgression of the bacterial endosymbiont Wolbachia into Aedes aegypti populations is a biocontrol approach being used to reduce arbovirus transmission. This requires mass release of Wolbachia-infected mosquitoes. While releases have been conducted using a variety of techniques, egg releases, using water-soluble capsules containing mosquito eggs and larval food, offer an attractive method due to its potential to reduce onsite resource requirements. However, optimisation of this approach is required to ensure there is no detrimental impact on mosquito fitness and to promote successful Wolbachia introgression. METHODS We determined the impact of storage time and temperature on wild-type (WT) and Wolbachia-infected (wMel or wAlbB strains) Ae. aegypti eggs. Eggs were stored inside capsules over 8 weeks at 18 °C or 22 °C and hatch rate, emergence rate and Wolbachia density were determined. We next examined egg quality and Wolbachia density after exposing eggs to 4-40 °C to determine how eggs may be impacted if exposed to extreme temperatures during shipment. RESULTS Encapsulating eggs for 8 weeks did not negatively impact egg viability or resulting adult emergence and Wolbachia density compared to controls. When eggs were exposed to temperatures within 4-36 °C for 48 h, their viability and resulting adult Wolbachia density were maintained; however, both were significantly reduced when exposed to 40 °C. CONCLUSIONS We describe the time and temperature limits for maintaining viability of Wolbachia-infected Ae. aegypti eggs when encapsulated or exposed to extreme temperatures. These findings could improve the efficiency of mass releases by providing transport and storage constraints to ensure only high-quality material is utilised during field releases.
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Affiliation(s)
- Megan J. Allman
- grid.1002.30000 0004 1936 7857Institute of Vector-borne Diseases, Monash University, Melbourne, VIC 3800 Australia
- grid.1002.30000 0004 1936 7857Department of Microbiology, Monash University, Melbourne, VIC 3800 Australia
| | - Ya-Hsun Lin
- grid.1002.30000 0004 1936 7857World Mosquito Program, Monash University, Melbourne, VIC 3800 Australia
| | - D. Albert Joubert
- grid.1002.30000 0004 1936 7857World Mosquito Program, Monash University, Melbourne, VIC 3800 Australia
| | - Jessica Addley-Cook
- grid.1002.30000 0004 1936 7857World Mosquito Program, Monash University, Melbourne, VIC 3800 Australia
| | - Maria Camila Mejía-Torres
- grid.1002.30000 0004 1936 7857World Mosquito Program, Monash University, Melbourne, VIC 3800 Australia
| | - Cameron P. Simmons
- grid.1002.30000 0004 1936 7857Institute of Vector-borne Diseases, Monash University, Melbourne, VIC 3800 Australia
- grid.1002.30000 0004 1936 7857World Mosquito Program, Monash University, Melbourne, VIC 3800 Australia
| | - Heather A. Flores
- grid.1002.30000 0004 1936 7857Institute of Vector-borne Diseases, Monash University, Melbourne, VIC 3800 Australia
- grid.1002.30000 0004 1936 7857School of Biological Sciences, Monash University, Melbourne, VIC 3800 Australia
| | - Johanna E. Fraser
- grid.1002.30000 0004 1936 7857Institute of Vector-borne Diseases, Monash University, Melbourne, VIC 3800 Australia
- grid.1002.30000 0004 1936 7857Department of Microbiology, Monash University, Melbourne, VIC 3800 Australia
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Yang SNY, Maher B, Wang C, Wagstaff KM, Fraser JE, Jans DA. High Throughput Screening Targeting the Dengue NS3-NS5 Interface Identifies Antivirals against Dengue, Zika and West Nile Viruses. Cells 2022; 11:730. [PMID: 35203378 PMCID: PMC8870125 DOI: 10.3390/cells11040730] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [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: 12/27/2021] [Revised: 02/03/2022] [Accepted: 02/11/2022] [Indexed: 12/04/2022] Open
Abstract
Dengue virus (DENV) threatens almost 70% of the world's population, with no effective therapeutic currently available and controversy surrounding the one approved vaccine. A key factor in dengue viral replication is the interaction between DENV nonstructural proteins (NS) 5 and 3 (NS3) in the infected cell. Here, we perform a proof-of-principle high-throughput screen to identify compounds targeting the NS5-NS3 binding interface. We use a range of approaches to show for the first time that two small molecules-repurposed drugs I-OMe tyrphostin AG538 (I-OMe-AG238) and suramin hexasodium (SHS)-inhibit NS5-NS3 binding at low μM concentration through direct binding to NS5 that impacts thermostability. Importantly, both have strong antiviral activity at low μM concentrations against not only DENV-2, but also Zika virus (ZIKV) and West Nile virus (WNV). This work highlights the NS5-NS3 binding interface as a viable target for the development of anti-flaviviral therapeutics.
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Affiliation(s)
| | | | | | | | | | - David A. Jans
- Nuclear Signalling Laboratory, Department of Biochemistry and Molecular Biology, Monash Biomedicine Discovery Institute, Monash University, Monash, VIC 3800, Australia; (S.N.Y.Y.); (B.M.); (C.W.); (K.M.W.); (J.E.F.)
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Abstract
Recent field trials have demonstrated that dengue incidence can be substantially reduced by introgressing strains of the endosymbiotic bacterium Wolbachia into Aedes aegypti mosquito populations. This strategy relies on Wolbachia reducing the susceptibility of Ae. aegypti to disseminated infection by positive-sense RNA viruses like dengue. However, RNA viruses are well known to adapt to antiviral pressures. Here, we review the viral infection stages where selection for Wolbachia-resistant virus variants could occur. We also consider the genetic constraints imposed on viruses that alternate between vertebrate and invertebrate hosts, and the likely selection pressures to which dengue virus might adapt in order to be effectively transmitted by Ae. aegypti that carry Wolbachia. While there are hurdles to dengue viruses developing resistance to Wolbachia, we suggest that long-term surveillance for resistant viruses should be an integral component of Wolbachia-introgression biocontrol programs.
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Affiliation(s)
| | - Heather A. Flores
- Institute of Vector-Borne Disease, Monash University, Clayton, Victoria, Australia
| | - Cameron P. Simmons
- World Mosquito Program, Institute of Vector-Borne Disease, Monash University, Clayton, Victoria, Australia
- Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
- Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Johanna E. Fraser
- Institute of Vector-Borne Disease, Monash University, Clayton, Victoria, Australia
- Department of Microbiology, Monash Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
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Fraser JE, O’Donnell TB, Duyvestyn JM, O’Neill SL, Simmons CP, Flores HA. Novel phenotype of Wolbachia strain wPip in Aedes aegypti challenges assumptions on mechanisms of Wolbachia-mediated dengue virus inhibition. PLoS Pathog 2020; 16:e1008410. [PMID: 32726353 PMCID: PMC7416964 DOI: 10.1371/journal.ppat.1008410] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [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: 02/13/2020] [Revised: 08/10/2020] [Accepted: 05/29/2020] [Indexed: 12/31/2022] Open
Abstract
The bacterial endosymbiont Wolbachia is a biocontrol tool that inhibits the ability of the Aedes aegypti mosquito to transmit positive-sense RNA viruses such as dengue and Zika. Growing evidence indicates that when Wolbachia strains wMel or wAlbB are introduced into local mosquito populations, human dengue incidence is reduced. Despite the success of this novel intervention, we still do not fully understand how Wolbachia protects mosquitoes from viral infection. Here, we demonstrate that the Wolbachia strain wPip does not inhibit virus infection in Ae. aegypti. We have leveraged this novel finding, and a panel of Ae. aegypti lines carrying virus-inhibitory (wMel and wAlbB) and non-inhibitory (wPip) strains in a common genetic background, to rigorously test a number of hypotheses about the mechanism of Wolbachia-mediated virus inhibition. We demonstrate that, contrary to previous suggestions, there is no association between a strain's ability to inhibit dengue infection in the mosquito and either its typical density in the midgut or salivary glands, or the degree to which it elevates innate immune response pathways in the mosquito. These findings, and the experimental platform provided by this panel of genetically comparable mosquito lines, clear the way for future investigations to define how Wolbachia prevents Ae. aegypti from transmitting viruses.
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Affiliation(s)
- Johanna E. Fraser
- World Mosquito Program, Institute of Vector-Borne Disease, Monash University, Clayton, Australia
| | - Tanya B. O’Donnell
- World Mosquito Program, Institute of Vector-Borne Disease, Monash University, Clayton, Australia
| | - Johanna M. Duyvestyn
- World Mosquito Program, Institute of Vector-Borne Disease, Monash University, Clayton, Australia
| | - Scott L. O’Neill
- World Mosquito Program, Institute of Vector-Borne Disease, Monash University, Clayton, Australia
| | - Cameron P. Simmons
- World Mosquito Program, Institute of Vector-Borne Disease, Monash University, Clayton, Australia
- Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
- Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Heather A. Flores
- World Mosquito Program, Institute of Vector-Borne Disease, Monash University, Clayton, Australia
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Yang SNY, Atkinson SC, Fraser JE, Wang C, Maher B, Roman N, Forwood JK, Wagstaff KM, Borg NA, Jans DA. Novel Flavivirus Antiviral That Targets the Host Nuclear Transport Importin α/β1 Heterodimer. Cells 2019; 8:cells8030281. [PMID: 30909636 PMCID: PMC6468590 DOI: 10.3390/cells8030281] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [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: 02/12/2019] [Revised: 03/19/2019] [Accepted: 03/20/2019] [Indexed: 12/20/2022] Open
Abstract
Dengue virus (DENV) threatens almost 70% of the world’s population, with no effective vaccine or therapeutic currently available. A key contributor to infection is nuclear localisation in the infected cell of DENV nonstructural protein 5 (NS5) through the action of the host importin (IMP) α/β1 proteins. Here, we used a range of microscopic, virological and biochemical/biophysical approaches to show for the first time that the small molecule GW5074 has anti-DENV action through its novel ability to inhibit NS5–IMPα/β1 interaction in vitro as well as NS5 nuclear localisation in infected cells. Strikingly, GW5074 not only inhibits IMPα binding to IMPβ1, but can dissociate preformed IMPα/β1 heterodimer, through targeting the IMPα armadillo (ARM) repeat domain to impact IMPα thermal stability and α-helicity, as shown using analytical ultracentrifugation, thermostability analysis and circular dichroism measurements. Importantly, GW5074 has strong antiviral activity at low µM concentrations against not only DENV-2, but also zika virus and West Nile virus. This work highlights DENV NS5 nuclear targeting as a viable target for anti-flaviviral therapeutics.
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Affiliation(s)
- Sundy N Y Yang
- Nuclear Signaling Laboratory, Monash Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Clayton, Vic. 3800, Australia.
| | - Sarah C Atkinson
- Infection & Immunity Program, Monash Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Clayton, Vic. 3800, Australia.
| | - Johanna E Fraser
- Nuclear Signaling Laboratory, Monash Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Clayton, Vic. 3800, Australia.
| | - Chunxiao Wang
- Nuclear Signaling Laboratory, Monash Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Clayton, Vic. 3800, Australia.
| | - Belinda Maher
- Nuclear Signaling Laboratory, Monash Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Clayton, Vic. 3800, Australia.
| | - Noelia Roman
- School of Biomedical Sciences, Charles Sturt University, Wagga Wagga, NSW 2650, Australia.
| | - Jade K Forwood
- School of Biomedical Sciences, Charles Sturt University, Wagga Wagga, NSW 2650, Australia.
| | - Kylie M Wagstaff
- Nuclear Signaling Laboratory, Monash Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Clayton, Vic. 3800, Australia.
| | - Natalie A Borg
- Infection & Immunity Program, Monash Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Clayton, Vic. 3800, Australia.
| | - David A Jans
- Nuclear Signaling Laboratory, Monash Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Clayton, Vic. 3800, Australia.
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Waugh JLS, Huang E, Fraser JE, Beyer KB, Trinh A, Mcilroy WE, Kulic D. Online Learning of Gait Models From Older Adult Data. IEEE Trans Neural Syst Rehabil Eng 2019; 27:733-742. [PMID: 30872234 DOI: 10.1109/tnsre.2019.2904477] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
This paper proposes a novel approach for online, individualized gait analysis, based on an adaptive periodic model of any gait signal. The proposed method learns a model of the gait cycle during online measurement, using a continuous representation that can adapt to inter- and intra-personal variability by creating an individualized model. Once the algorithm has converged to the input signal, key gait events can be identified based on the estimated gait phase and amplitude. The approach is implemented and tested on retirement home resident 6 min walk (6MW) data using wearable accelerometers at the ankle. The proposed approach converges within approximately four gait cycles and achieves 3% error in detecting initial swing events.11 An early version of this work was presented in [1]. A more extensive description of related work and an extended method, including optimization of learning rates, were added to this paper. Further, this paper applies and evaluates the method to a new and much larger gait dataset taken from older adults who each have a variety of medical conditions. Therefore, the experimental protocol was also updated and the results are entirely novel.
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Fraser JE, De Bruyne JT, Iturbe-Ormaetxe I, Stepnell J, Burns RL, Flores HA, O’Neill SL. Novel Wolbachia-transinfected Aedes aegypti mosquitoes possess diverse fitness and vector competence phenotypes. PLoS Pathog 2017; 13:e1006751. [PMID: 29216317 PMCID: PMC5736235 DOI: 10.1371/journal.ppat.1006751] [Citation(s) in RCA: 75] [Impact Index Per Article: 10.7] [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: 07/06/2017] [Revised: 12/19/2017] [Accepted: 11/13/2017] [Indexed: 11/18/2022] Open
Abstract
Wolbachia pipientis from Drosophila melanogaster (wMel) is an endosymbiotic bacterium that restricts transmission of human pathogenic flaviviruses and alphaviruses, including dengue, Zika, and chikungunya viruses, when introduced into the mosquito vector Aedes aegypti. To date, wMel-infected Ae. aegypti have been released in field trials in 5 countries to evaluate the effectiveness of this strategy for disease control. Despite the success in establishing wMel-infected mosquitoes in wild populations, and the well-characterized antiviral capabilities of wMel, transinfecting different or additional Wolbachia strains into Ae. aegypti may improve disease impact, and perhaps more importantly, could provide a strategy to account for the possible evolution of resistant arboviruses. Here, we report the successful transinfection of Ae. aegypti with the Wolbachia strains wMelCS (D. melanogaster), wRi (D. simulans) and wPip (Culex quinquefasciatus) and assess the effects on Ae. aegypti fitness, cytoplasmic incompatibility, tissue tropism and pathogen blocking in a laboratory setting. The results demonstrate that wMelCS provides a similar degree of protection against dengue virus as wMel following an infectious blood meal, and significantly reduces viral RNA levels beyond that of wMel following a direct challenge with infectious virus in mosquitoes, with no additional fitness cost to the host. The protection provided by wRi is markedly weaker than that of wMelCS, consistent with previous characterisations of these lines in Drosophila, while wPip was found to substantially reduce the fitness of Ae. aegypti. Thus, we determine wMelCS as a key candidate for further testing in field-relevant fitness tests and viremic blood feeding challenges in a clinical setting to determine if it may represent an alternative Wolbachia strain with more desirable attributes than wMel for future field testing. Dengue viruses are transmitted by the Aedes aegypti mosquito, with an estimated 390 million human infections occurring per year worldwide. There is no approved antiviral therapeutic, and vaccines described so far have had limited efficacy. Recently, the endosymbiotic bacterium Wolbachia from Drosophila melanogaster (wMel) has been used to infect Ae. aegypti populations as a novel technology for reducing dengue virus transmission. Here we report the generation of three new mosquito lines infected with the Wolbachia strains wMelCS, wRi and wPip. Each line induced cytoplasmic incompatibility and was effectively maternally transmitted, as required for rapid spread through uninfected mosquito populations. Each Wolbachia strain was also found to reside in the salivary glands; a key tissue involved in viral transmission. Perhaps most importantly, wMelCS inhibited dengue virus replication and dissemination in mosquitoes following an infectious blood meal or intrathoracic injection, providing a similar level of protection as that described for wMel. wMelCS therefore warrants further investigation as a potential release strain in future field trials.
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Affiliation(s)
- Johanna E. Fraser
- Institute of Vector-Borne Disease, Monash University, Clayton, VIC, Australia
| | | | | | - Justin Stepnell
- Institute of Vector-Borne Disease, Monash University, Clayton, VIC, Australia
| | - Rhiannon L. Burns
- Institute of Vector-Borne Disease, Monash University, Clayton, VIC, Australia
| | - Heather A. Flores
- Institute of Vector-Borne Disease, Monash University, Clayton, VIC, Australia
| | - Scott L. O’Neill
- Institute of Vector-Borne Disease, Monash University, Clayton, VIC, Australia
- * E-mail:
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Fraser JE, Watanabe S, Wang C, Chan WKK, Maher B, Lopez-Denman A, Hick C, Wagstaff KM, Mackenzie JM, Sexton PM, Vasudevan SG, Jans DA. A nuclear transport inhibitor that modulates the unfolded protein response and provides in vivo protection against lethal dengue virus infection. J Infect Dis 2014; 210:1780-91. [PMID: 24903662 DOI: 10.1093/infdis/jiu319] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
BACKGROUND Dengue virus (DENV) is estimated to cause 390 million infections each year, but there is no licensed vaccine or therapeutic currently available. METHODS We describe a novel, high-throughput screen to identify compounds inhibiting the interaction between DENV nonstructural protein 5 and host nuclear transport proteins. We document the antiviral properties of a lead compound against all 4 serotypes of DENV, antibody-dependent enhanced (ADE) infection, and ex vivo and in vivo DENV infections. In addition, we use quantitative reverse-transcription polymerase chain reaction to examine cellular effects upon compound addition. RESULTS We identify N-(4-hydroxyphenyl) retinamide (4-HPR) as effective in protecting against DENV-1-4 and DENV-1 ADE infections, with 50% effective concentrations in the low micromolar range. 4-HPR but not the closely related N-(4-methoxyphenyl) retinamide (4-MPR) could reduce viral RNA levels and titers when applied to an established infection. 4-HPR but not 4-MPR was found to specifically upregulate the protein kinase R-like endoplasmic reticulum kinase arm of the unfolded protein response. Strikingly, 4-HPR but not 4-MPR restricted infection in peripheral blood mononuclear cells and in a lethal ADE-infection mouse model. CONCLUSIONS 4-HPR is a novel antiviral that modulates the unfolded protein response, effective against DENV1-4 at concentrations achievable in the plasma in a clinical setting, and provides protection in a lethal mouse model.
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Affiliation(s)
- Johanna E Fraser
- Nuclear Signaling Laboratory, Department of Biochemistry and Molecular Biology, Monash University
| | - Satoru Watanabe
- Program in Emerging Infectious Diseases, Duke-NUS Graduate Medical School, Singapore
| | - Chunxiao Wang
- Nuclear Signaling Laboratory, Department of Biochemistry and Molecular Biology, Monash University
| | - Wing Ki Kitti Chan
- Program in Emerging Infectious Diseases, Duke-NUS Graduate Medical School, Singapore
| | - Belinda Maher
- Nuclear Signaling Laboratory, Department of Biochemistry and Molecular Biology, Monash University
| | - Adam Lopez-Denman
- Department of Microbiology and Immunology, University of Melbourne Department of Microbiology, La Trobe University, Bundoora
| | - Caroline Hick
- Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Australia
| | - Kylie M Wagstaff
- Nuclear Signaling Laboratory, Department of Biochemistry and Molecular Biology, Monash University
| | | | - Patrick M Sexton
- Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Australia
| | - Subhash G Vasudevan
- Program in Emerging Infectious Diseases, Duke-NUS Graduate Medical School, Singapore
| | - David A Jans
- Nuclear Signaling Laboratory, Department of Biochemistry and Molecular Biology, Monash University
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Zhao XB, Fraser JE, Alexander C, Lockett C, White BJ. Synthesis and characterization of a novel double crosslinked hyaluronan hydrogel. J Mater Sci Mater Med 2002; 13:11-16. [PMID: 15348198 DOI: 10.1023/a:1013618115163] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Hyaluronan has great potential in medicine as a biomaterial. However, in its native form, hyaluronan is rapidly metabolized in vivo by free radicals and enzymes such as hyaluronidase, and it is highly soluble. Various methods have been adopted therefore, to modify the physicochemical properties of hyaluronan, while maintaining biocompatibility, and thereby widen its spectrum of therapeutic applications. Hyaluronan has four reactive groups (acetamido, carboxyl, hydroxyl and the reducing end) available for crosslinking to itself or other polymers. Using a variety of crosslinking agents, researchers have developed a host of crosslinked hyaluronan derivatives with an increased in vivo residence time. This chemical modification has enabled the production of gels and films, which can be used in applications such as the prevention of post-surgical adhesions, wound healing and dermal augmentation. We have found that if hyaluronan is crosslinked to itself, or to other polymers (either synthetic or biopolymer), in two stages, then a high degree of crosslinking is achieved, conferring improved biostability. In each of the two stages, the same crosslinking agent is used, but different functional groups are bound by altering the reaction conditions. The novel process can be tailored to yield water insoluble gels and films with a broad range of physical and chemical characteristics, and greater resistance to degradation by hyaluronidase and free radicals. These derivatives are currently undergoing biocompatibility testing, and should ultimately lead to a series of innovative second-generation medical products.
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Affiliation(s)
- X B Zhao
- Vitrolife UK Ltd., Heriot Watt Research Park, Edinburgh EH14 4AP, UK.
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11
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Abstract
BACKGROUND Prostatic secretory protein of 94 amino acids (PSP94) is one of the predominant proteins found in human seminal fluid. Limited information is available regarding a physiological function for PSP94. An important step in the elucidation of this function is the determination of the mechanism of interaction of PSP94 with potential cellular targets. METHODS Equilibrium binding assay was employed to demonstrate specific binding of biotinylated-PSP94 to the LNCaP and PC-3 cell lines. Binding proteins were partially purified by PSP94 affinity-chromatography from LNCaP, PC-3 cells, and prostate tissues. RESULTS Binding of biotinylated-PSP94 to LNCaP and PC-3 cells was saturable and time and temperature dependent. The binding could be specifically competitively inhibited by unlabelled PSP94. Two types of PSP94 binding sites with distinct affinity (Kd) and density (Bmax) were determined by Scatchard analysis for each of the two cell lines. For the LNCaP cells, these values were Kd 1 = 0.75 nM and Bmax1 = 300 fmol/mg protein and Kd 2 = 4.5 nM, Bmax2 = 780 fmol/mg protein, respectively. Similar affinity and density results were obtained for PC-3 cells: Kd 1 = 0.83 nM, Bmax1 = 250 fmol/mg protein, and Kd 2 = 5.0 nM, Bmax2 = 700 fmol/mg. The binding of biotinylated-PSP94 to the LNCaP cells was competitively inhibited by the partially purified proteins. Analysis of these proteins SDS-PAGE showed three main bands and the molecular weights of these three bands were approximately 180, 100 and 60 kD, respectively. CONCLUSIONS The data showed the presence of specific binding proteins to the PSP94 in LNCaP, PC-3 cells, and prostate tissue.
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Affiliation(s)
- J P Yang
- Department of Microbiology and Immunology, University of Western Ontario, London, Canada.
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Baijal-Gupta M, Fraser JE, Clarke MW, Xuan JW, Finkelman MA. A new scalable purification procedure for prostatic secretory protein (PSP94) from human seminal plasma. Protein Expr Purif 1996; 8:483-8. [PMID: 8954897 DOI: 10.1006/prep.1996.0128] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [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: 02/03/2023]
Abstract
A simple three-step procedure for the purification of native prostate secretory protein (PSP94) from human seminal plasma is described. The steps are ammonium sulfate fractionation followed by a Macro-Prep S support (cation) flowthrough process and the final Macro-Prep high Q support (anion exchange) chromatography using two step-gradient elution. The benefits of this procedure lie in its simplicity, speed, and relatively inexpensive materials, thus providing advantages over the previously reported schemes. The purity of the product as judged by single band on SDS-polyacrylaminde gel electrophoresis was equivalent to that attained by analytical HPLC anion exchange procedure. Yields were in the range of 18-25 mg highly pure PSP94 per 50 ml of seminal plasma. The desalted, lyophilized, purified PSP94 sample was characterized by SDS-PAGE, Western blot, and N-terminal sequencing. All parameters tested confirm its identity. Preliminary data show that this procedure is suitable for a large-scale production. The direct quantitation of PSP94 by SDS-PAGE and densitometric image analysis at various purification steps for evaluating the recovery of PSP94 is described. The results obtained show that this is an efficient strategy for preparation of highly purified native PSP94.
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Abstract
PSP94 has the potential to be a useful diagnostic marker and therapeutic agent in prostate cancer. Recently, different immunoassay systems for quantitative analysis of PSP94 in clinical samples have been developed, but the epitope structure of PSP94 protein has not been elucidated. In this study, we report an Escherichia coli expression system for recombinant GST-PSP94 fusion protein. GST-PSP94 contains antigenic determinants similar to natural PSP94 protein (determined both by Western blotting experiments and by ELISA) and can be used to study the structure of natural PSP94 antigen. Since GST-PSP94 was expressed in E. coli and purification involved a denaturing process, we propose that the epitope structure of PSP94 is linear and largely dependent on the primary amino acid sequence, rather than conformational structure. This hypothesis was supported by reciprocal competition in ELISA among natural, GST-PSP94 fusion protein, and purified recombinant PSP94 protein. The results demonstrate that the various forms of PSP94 can compete with each other in binding to rabbit PSP94 polyclonal antibody, although the natural PSP94 has a slightly higher affinity. When natural and recombinant PSP94 protein were denatured in vitro with urea and alkali, no effect on the binding to antibody was found. The epitope activity of natural PSP94 was also shown to be resistant to the treatment of detergent and reducing agent. The location of one of the linear epitopes recognized by the PSP94 antibody was determined to be in the N-terminus by using two synthetic peptides representing N- and C-terminal sequences. Competitive ELISA between the N-terminal peptide and PSP94 protein indicate that both natural and GST-PSP94 have similar immunoactive N-termini.
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Affiliation(s)
- J W Xuan
- Department of Surgery, University of Western Ontario, Canada.
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Eddy FB, Fraser JE. Sialic acid and mucus production in rainbow trout (Salmo gairdneri Richardson) in response to zinc and seawater. Comp Biochem Physiol C Comp Pharmacol 1982; 73:357-9. [PMID: 6129101 DOI: 10.1016/0306-4492(82)90135-6] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
1. Rainbow trout exposed to seawater or 20 ppm zinc showed hypersecretion of mucus whose sialic acid (N-acetylneuraminic acid) content 0.192 micro M g-1 mucus was not significantly different to that produced by trout in freshwater, 0.184 micro M g-1 mucus. 2. Measurement of sialic content in the water indicated its production (and therefore mucus production) was about 70 times higher in seawater and 20 ppm zinc compared to freshwater production.
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