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Perera DR, Ranadeva ND, Sirisena K, Wijesinghe KJ. Roles of NS1 Protein in Flavivirus Pathogenesis. ACS Infect Dis 2024; 10:20-56. [PMID: 38110348 DOI: 10.1021/acsinfecdis.3c00566] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2023]
Abstract
Flaviviruses such as dengue, Zika, and West Nile viruses are highly concerning pathogens that pose significant risks to public health. The NS1 protein is conserved among flaviviruses and is synthesized as a part of the flavivirus polyprotein. It plays a critical role in viral replication, disease progression, and immune evasion. Post-translational modifications influence NS1's stability, secretion, antigenicity, and interactions with host factors. NS1 protein forms extensive interactions with host cellular proteins allowing it to affect vital processes such as RNA processing, gene expression regulation, and cellular homeostasis, which in turn influence viral replication, disease pathogenesis, and immune responses. NS1 acts as an immune evasion factor by delaying complement-dependent lysis of infected cells and contributes to disease pathogenesis by inducing endothelial cell damage and vascular leakage and triggering autoimmune responses. Anti-NS1 antibodies have been shown to cross-react with host endothelial cells and platelets, causing autoimmune destruction that is hypothesized to contribute to disease pathogenesis. However, in contrast, immunization of animal models with the NS1 protein confers protection against lethal challenges from flaviviruses such as dengue and Zika viruses. Understanding the multifaceted roles of NS1 in flavivirus pathogenesis is crucial for effective disease management and control. Therefore, further research into NS1 biology, including its host protein interactions and additional roles in disease pathology, is imperative for the development of strategies and therapeutics to combat flavivirus infections successfully. This Review provides an in-depth exploration of the current available knowledge on the multifaceted roles of the NS1 protein in the pathogenesis of flaviviruses.
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Affiliation(s)
- Dayangi R Perera
- Department of Chemistry, Faculty of Science, University of Colombo, Sri Lanka 00300
| | - Nadeeka D Ranadeva
- Department of Biomedical Science, Faculty of Health Sciences, KIU Campus Sri Lanka 10120
| | - Kavish Sirisena
- Department of Chemistry, Faculty of Science, University of Colombo, Sri Lanka 00300
- Section of Genetics, Institute for Research and Development in Health and Social Care, Sri Lanka 10120
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Ceconi M, Ariën KK, Delputte P. Diagnosing arthropod-borne flaviviruses: non-structural protein 1 (NS1) as a biomarker. Trends Microbiol 2023:S0966-842X(23)00334-7. [PMID: 38135616 DOI: 10.1016/j.tim.2023.11.016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2023] [Revised: 11/29/2023] [Accepted: 11/30/2023] [Indexed: 12/24/2023]
Abstract
In recent decades, the presence of flaviviruses of concern for human health in Europe has drastically increased,exacerbated by the effects of climate change - which has allowed the vectors of these viruses to expand into new territories. Co-circulation of West Nile virus (WNV), Usutu virus (USUV), and tick-borne encephalitis virus (TBEV) represents a threat to the European continent, and this is further complicated by the difficulty of obtaining an early and discriminating diagnosis of infection. Moreover, the possibility of introducing non-endemic pathogens, such as Japanese encephalitis virus (JEV), further complicates accurate diagnosis. Current flavivirus diagnosis is based mainly on RT-PCR and detection of virus-specific antibodies. Yet, both techniques suffer from limitations, and the development of new assays that can provide an early, rapid, low-cost, and discriminating diagnosis of viral infection is warranted. In the pursuit of ideal diagnostic assays, flavivirus non-structural protein 1 (NS1) serves as an excellent target for developing diagnostic assays based on both the antigen itself and the antibodies produced against it. This review describes the potential of such NS1-based diagnostic methods, focusing on the application of flaviviruses that co-circulate in Europe.
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Affiliation(s)
- Martina Ceconi
- Laboratory for Microbiology, Parasitology and Hygiene, Infla-Med Centre of Excellence, University of Antwerp, Antwerp 2610, Belgium
| | - Kevin K Ariën
- Virology Unit, Department of Biomedical Sciences, Institute of Tropical Medicine, Antwerp 2000, Belgium; Department of Biomedical Sciences, University of Antwerp, Antwerp 2610, Belgium
| | - Peter Delputte
- Laboratory for Microbiology, Parasitology and Hygiene, Infla-Med Centre of Excellence, University of Antwerp, Antwerp 2610, Belgium.
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Conde JN, Himmler GE, Mladinich MC, Setoh YX, Amarilla AA, Schutt WR, Saladino N, Gorbunova EE, Salamango DJ, Benach J, Kim HK, Mackow ER. Establishment of a CPER reverse genetics system for Powassan virus defines attenuating NS1 glycosylation sites and an infectious NS1-GFP11 reporter virus. mBio 2023; 14:e0138823. [PMID: 37489888 PMCID: PMC10470542 DOI: 10.1128/mbio.01388-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Accepted: 06/06/2023] [Indexed: 07/26/2023] Open
Abstract
Powassan virus (POWV) is an emerging tick-borne Flavivirus that causes lethal encephalitis and long-term neurologic damage. Currently, there are no POWV therapeutics, licensed vaccines, or reverse genetics systems for producing infectious POWVs from recombinant DNA. Using a circular polymerase extension reaction (CPER), we generated recombinant LI9 (recLI9) POWVs with attenuating NS1 protein mutations and a recLI9-split-eGFP reporter virus. NS1 proteins are highly conserved glycoproteins that regulate replication, spread, and neurovirulence. POWV NS1 contains three putative N-linked glycosylation sites that we modified individually in infectious recLI9 mutants (N85Q, N208Q, and N224Q). NS1 glycosylation site mutations reduced replication kinetics and were attenuated, with 1-2 log decreases in titer. Severely attenuated recLI9-N224Q exhibited a 2- to 3-day delay in focal cell-to-cell spread and reduced NS1 secretion but was lethal when intracranially inoculated into suckling mice. However, footpad inoculation of recLI9-N224Q resulted in the survival of 80% of mice and demonstrated that NS1-N224Q mutations reduce POWV neuroinvasion in vivo. To monitor NS1 trafficking, we CPER fused a split GFP11-tag to the NS1 C-terminus and generated an infectious reporter virus, recLI9-NS1-GFP11. Cells infected with recLI9-NS1-GFP11 revealed NS1 trafficking in live cells and the novel formation of large NS1-lined intracellular vesicles. An infectious recLI9-NS1-GFP11 reporter virus permits real-time analysis of NS1 functions in POWV replication, assembly, and secretion and provides a platform for evaluating antiviral compounds. Collectively, our robust POWV reverse genetics system permits analysis of viral spread and neurovirulence determinants in vitro and in vivo and enables the rational genetic design of live attenuated POWV vaccines. IMPORTANCE Our findings newly establish a mechanism for genetically modifying Powassan viruses (POWVs), systematically defining pathogenic determinants and rationally designing live attenuated POWV vaccines. This initial study demonstrates that mutating POWV NS1 glycosylation sites attenuates POWV spread and neurovirulence in vitro and in vivo. Our findings validate a robust circular polymerase extension reaction approach as a mechanism for developing, and evaluating, attenuated genetically modified POWVs. We further designed an infectious GFP-tagged reporter POWV that permits us to monitor secretory trafficking of POWV in live cells, which can be applied to screen potential POWV replication inhibitors. This robust system for modifying POWVs provides the ability to define attenuating POWV mutations and create genetically attenuated recPOWV vaccines.
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Affiliation(s)
- Jonas N. Conde
- Department of Microbiology and Immunology, Stony Brook University, Stony Brook, New York, USA
- School of Chemistry and Molecular Biosciences, University of Queensland, St Lucia, Queensland, Australia
| | - Grace E. Himmler
- Department of Microbiology and Immunology, Stony Brook University, Stony Brook, New York, USA
- School of Chemistry and Molecular Biosciences, University of Queensland, St Lucia, Queensland, Australia
- Molecular and Cell Biology Program, Stony Brook University, Stony Brook, New York, USA
| | - Megan C. Mladinich
- Department of Microbiology and Immunology, Stony Brook University, Stony Brook, New York, USA
- School of Chemistry and Molecular Biosciences, University of Queensland, St Lucia, Queensland, Australia
| | - Yin Xiang Setoh
- Microbiology and Molecular Epidemiology Division, Environmental Health Institute, National Environmental Agency, Singapore, Singapore
| | - Alberto A. Amarilla
- School of Chemistry and Molecular Biosciences, University of Queensland, St Lucia, Queensland, Australia
| | - William R. Schutt
- Department of Microbiology and Immunology, Stony Brook University, Stony Brook, New York, USA
- Center for Infectious Disease, Stony Brook University, Stony Brook, New York, USA
| | - Nicholas Saladino
- Department of Microbiology and Immunology, Stony Brook University, Stony Brook, New York, USA
| | - Elena E. Gorbunova
- Department of Microbiology and Immunology, Stony Brook University, Stony Brook, New York, USA
- Center for Infectious Disease, Stony Brook University, Stony Brook, New York, USA
| | - Daniel J. Salamango
- Department of Microbiology and Immunology, Stony Brook University, Stony Brook, New York, USA
| | - Jorge Benach
- Department of Microbiology and Immunology, Stony Brook University, Stony Brook, New York, USA
- Center for Infectious Disease, Stony Brook University, Stony Brook, New York, USA
| | - Hwan Keun Kim
- Department of Microbiology and Immunology, Stony Brook University, Stony Brook, New York, USA
- Molecular and Cell Biology Program, Stony Brook University, Stony Brook, New York, USA
- Center for Infectious Disease, Stony Brook University, Stony Brook, New York, USA
| | - Erich R. Mackow
- Department of Microbiology and Immunology, Stony Brook University, Stony Brook, New York, USA
- Molecular and Cell Biology Program, Stony Brook University, Stony Brook, New York, USA
- Center for Infectious Disease, Stony Brook University, Stony Brook, New York, USA
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