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Samune Y, Saito A, Sasaki T, Koketsu R, Srimark N, Phadungsombat J, Yokoyama M, Kotani O, Sato H, Yamanaka A, Haga S, Okamoto T, Kurosu T, Nakayama EE, Shioda T. Genetic regions affecting the replication and pathogenicity of dengue virus type 2. PLoS Negl Trop Dis 2024; 18:e0011885. [PMID: 38190404 PMCID: PMC10798627 DOI: 10.1371/journal.pntd.0011885] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2023] [Revised: 01/19/2024] [Accepted: 12/26/2023] [Indexed: 01/10/2024] Open
Abstract
Dengue is a mosquito-borne disease that has spread to over 100 countries. Its symptoms vary from the relatively mild acute febrile illness called dengue fever to the much more severe dengue shock syndrome. Dengue is caused by dengue virus (DENV), which belongs to the Flavivirus genus of the family Flaviviridae. There are four serotypes of DENV, i.e., DENV1 to DENV4, and each serotype is divided into distinct genotypes. Thailand is an endemic area where all four serotypes of DENV co-circulate. Genome sequencing of the DENV2 that was isolated in Thailand in 2016 and 2017 revealed the emergence of the Cosmopolitan genotype and its co-circulation with the Asian-I genotype. However, it was unclear whether different genotypes have different levels of viral replication and pathogenicity. Focus-forming assay (FFA) results showed that clinical isolates of these genotypes differed in focus size and proliferative capacity. Using circular polymerase extension reaction, we generated parental and chimeric viruses with swapped genes between these two DENV2 genotypes, and compared their focus sizes and infectivity titers using FFA. The results showed that the focus size was larger when the structural proteins and/or non-structural NS1-NS2B proteins were derived from the Cosmopolitan virus. The infectious titers were consistent with the focus sizes. Single-round infectious particle assay results confirmed that chimeric viruses with Cosmopolitan type structural proteins, particularly prM/E, had significantly increased luciferase activity. Replicon assay results showed that Cosmopolitan NS1-NS2B proteins had increased reporter gene expression levels. Furthermore, in interferon-receptor knock-out mice, viruses with Cosmopolitan structural and NS1-NS2B proteins had higher titers in the blood, and caused critical disease courses. These results suggested that differences in the sequences within the structural and NS1-NS2B proteins may be responsible for the differences in replication, pathogenicity, and infectivity between the Asian-I and Cosmopolitan viruses.
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Affiliation(s)
- Yoshihiro Samune
- Department of Viral Infections, Research Institute for Microbial Diseases, Osaka University, Osaka, Japan
| | - Akatsuki Saito
- Department of Veterinary Science, Faculty of Agriculture, University of Miyazaki, Miyazaki, Japan
| | - Tadahiro Sasaki
- Department of Viral Infections, Research Institute for Microbial Diseases, Osaka University, Osaka, Japan
| | - Ritsuko Koketsu
- Department of Viral Infections, Research Institute for Microbial Diseases, Osaka University, Osaka, Japan
| | - Narinee Srimark
- Thailand-Japan Research Collaboration Center on Emerging and Re-emerging Infections, Research Institute for Microbial Diseases, Osaka University, Osaka, Japan
| | - Juthamas Phadungsombat
- Department of Viral Infections, Research Institute for Microbial Diseases, Osaka University, Osaka, Japan
| | - Masaru Yokoyama
- Pathogen Genomics Center, National Institute of Infectious Diseases, Musashimurayama, Japan
| | - Osamu Kotani
- Pathogen Genomics Center, National Institute of Infectious Diseases, Musashimurayama, Japan
| | - Hironori Sato
- Pathogen Genomics Center, National Institute of Infectious Diseases, Musashimurayama, Japan
| | - Atsushi Yamanaka
- Thailand-Japan Research Collaboration Center on Emerging and Re-emerging Infections, Research Institute for Microbial Diseases, Osaka University, Osaka, Japan
| | - Saori Haga
- Institute for Advanced Co-Creation Studies, Research Institute for Microbial Diseases, Osaka University, Osaka, Japan
| | - Toru Okamoto
- Institute for Advanced Co-Creation Studies, Research Institute for Microbial Diseases, Osaka University, Osaka, Japan
| | - Takeshi Kurosu
- Department of Virology I, National Institute of Infectious Diseases, Musashimurayama, Japan
| | - Emi E. Nakayama
- Department of Viral Infections, Research Institute for Microbial Diseases, Osaka University, Osaka, Japan
| | - Tatsuo Shioda
- Department of Viral Infections, Research Institute for Microbial Diseases, Osaka University, Osaka, Japan
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Masuda T, Kotani O, Yokoyama M, Abe Y, Kawai G, Sato H. Cis-Allosteric Regulation of HIV-1 Reverse Transcriptase by Integrase. Viruses 2022; 15:31. [PMID: 36680070 PMCID: PMC9864105 DOI: 10.3390/v15010031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2022] [Revised: 12/19/2022] [Accepted: 12/19/2022] [Indexed: 12/24/2022] Open
Abstract
Reverse transcriptase (RT) and integrase (IN) are encoded tandemly in the pol genes of retroviruses. We reported recently that HIV-1 RT and IN need to be supplied as the pol precursor intermediates, in which RT and IN are in fusion form (RTIN) to exert efficient reverse transcription in the context of HIV-1 replication. The mechanism underlying RTIN's effect, however, remains to be elucidated. In this study, we examined the effect of IN fusion on RT during reverse transcription by an in vitro cell-free assay, using recombinant HIV-1 RTIN (rRTIN). We found that, compared to recombinant RT (rRT), rRTIN generated significantly higher cDNAs under physiological concentrations of dNTPs (less than 10 μM), suggesting increased affinity of RTIN to dNTPs. Importantly, the cleavage of RTIN with HIV-1 protease reduced cDNA levels at a low dose of dNTPs. Similarly, sensitivities against RT inhibitors were significantly altered in RTIN form. Finally, analysis of molecular dynamics simulations of RT and RTIN suggested that IN can influence the structural dynamics of the RT active center and the inhibitor binding pockets in cis. Thus, we demonstrated, for the first time, the cis-allosteric regulatory roles of IN in RT structure and enzymatic activity.
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Affiliation(s)
- Takao Masuda
- Department of Immunotherapeutics, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), Yushima, 1-5-45 Bunkyo-ku, Tokyo 113-8519, Japan
| | - Osamu Kotani
- Laboratory of Viral Genomics, Pathogen Genomics Center, National Institute of Infectious Diseases, Gakuen, 4-7-1, Musashimurayama-shi, Tokyo 208-0011, Japan
| | - Masaru Yokoyama
- Laboratory of Viral Genomics, Pathogen Genomics Center, National Institute of Infectious Diseases, Gakuen, 4-7-1, Musashimurayama-shi, Tokyo 208-0011, Japan
| | - Yuya Abe
- Department of Immunotherapeutics, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), Yushima, 1-5-45 Bunkyo-ku, Tokyo 113-8519, Japan
| | - Gota Kawai
- Department of Life Science, Faculty of Advanced Engineering, Chiba Institute of Technology, 2-17-1 Tsudanuma, Narashino-shi, Chiba 275-0016, Japan
| | - Hironori Sato
- Laboratory of Viral Genomics, Pathogen Genomics Center, National Institute of Infectious Diseases, Gakuen, 4-7-1, Musashimurayama-shi, Tokyo 208-0011, Japan
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Unique Mode of Antiviral Action of a Marine Alkaloid against Ebola Virus and SARS-CoV-2. Viruses 2022; 14:v14040816. [PMID: 35458549 PMCID: PMC9028129 DOI: 10.3390/v14040816] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Revised: 03/24/2022] [Accepted: 04/02/2022] [Indexed: 11/16/2022] Open
Abstract
Lamellarin α 20-sulfate is a cell-impenetrable marine alkaloid that can suppress infection that is mediated by the envelope glycoprotein of human immunodeficiency virus type 1. We explored the antiviral action and mechanisms of this alkaloid against emerging enveloped RNA viruses that use endocytosis for infection. The alkaloid inhibited the infection of retroviral vectors that had been pseudotyped with the envelope glycoprotein of Ebola virus and SARS-CoV-2. The antiviral effects of lamellarin were independent of the retrovirus Gag-Pol proteins. Interestingly, although heparin and dextran sulfate suppressed the cell attachment of vector particles, lamellarin did not. In silico structural analyses of the trimeric glycoprotein of the Ebola virus disclosed that the principal lamellarin-binding site is confined to a previously unappreciated cavity near the NPC1-binding site and fusion loop, whereas those for heparin and dextran sulfate were dispersed across the attachment and fusion subunits of the glycoproteins. Notably, lamellarin binding to this cavity was augmented under conditions where the pH was 5.0. These results suggest that the final action of the alkaloid against Ebola virus is specific to events following endocytosis, possibly during conformational glycoprotein changes in the acidic environment of endosomes. Our findings highlight the unique biological and physicochemical features of lamellarin α 20-sulfate and should lead to the further use of broadly reactive antivirals to explore the structural mechanisms of virus replication.
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Kotani O, Suzuki Y, Saito S, Ainai A, Ueno A, Hemmi T, Sano K, Tabata K, Yokoyama M, Suzuki T, Hasegawa H, Sato H. Structure-Guided Creation of an Anti-HA Stalk Antibody F11 Derivative That Neutralizes Both F11-Sensitive and -Resistant Influenza A(H1N1)pdm09 Viruses. Viruses 2021; 13:v13091733. [PMID: 34578314 PMCID: PMC8473006 DOI: 10.3390/v13091733] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Revised: 08/24/2021] [Accepted: 08/26/2021] [Indexed: 12/05/2022] Open
Abstract
The stalk domain of influenza virus envelope glycoprotein hemagglutinin (HA) constitutes the axis connecting the head and transmembrane domains, and plays pivotal roles in conformational rearrangements of HA for virus infection. Here we characterized molecular interactions between the anti-HA stalk neutralization antibody F11 and influenza A(H1N1)pdm09 HA to understand the structural basis of the actions and modifications of this antibody. In silico structural analyses using a model of the trimeric HA ectodomain indicated that the F11 Fab fragment has physicochemical properties, allowing it to crosslink two HA monomers by binding to a region near the proteolytic cleavage site of the stalk domain. Interestingly, the F11 binding allosterically caused a marked suppression of the structural dynamics of the HA cleavage loop and flanking regions. Structure-guided mutagenesis of the F11 antibody revealed a critical residue in the F11 light chain for the F11-mediated neutralization. Finally, the mutagenesis led to identification of a unique F11 derivative that can neutralize both F11-sensitive and F11-resistant A(H1N1)pdm09 viruses. These results raise the possibility that F11 sterically and physically disturbs proteolytic cleavage of HA for the ordered conformational rearrangements and suggest that in silico guiding experiments can be useful to create anti-HA stalk antibodies with new phenotypes.
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Affiliation(s)
- Osamu Kotani
- Center for Pathogen Genomics, National Institute of Infectious Diseases, Tokyo 208-0011, Japan; (M.Y.); (H.S.)
- Correspondence: (O.K.); (S.S.)
| | - Yasushi Suzuki
- Center for Influenza and Respiratory Virus Research, National Institute of Infectious Diseases, Tokyo 208-0011, Japan; (Y.S.); (H.H.)
| | - Shinji Saito
- Department of Pathology, National Institute of Infectious Diseases, Tokyo 162-8640, Japan; (A.A.); (A.U.); (T.H.); ka-- (K.S.); (K.T.); (T.S.)
- Correspondence: (O.K.); (S.S.)
| | - Akira Ainai
- Department of Pathology, National Institute of Infectious Diseases, Tokyo 162-8640, Japan; (A.A.); (A.U.); (T.H.); ka-- (K.S.); (K.T.); (T.S.)
| | - Akira Ueno
- Department of Pathology, National Institute of Infectious Diseases, Tokyo 162-8640, Japan; (A.A.); (A.U.); (T.H.); ka-- (K.S.); (K.T.); (T.S.)
| | - Takuya Hemmi
- Department of Pathology, National Institute of Infectious Diseases, Tokyo 162-8640, Japan; (A.A.); (A.U.); (T.H.); ka-- (K.S.); (K.T.); (T.S.)
| | - Kaori Sano
- Department of Pathology, National Institute of Infectious Diseases, Tokyo 162-8640, Japan; (A.A.); (A.U.); (T.H.); ka-- (K.S.); (K.T.); (T.S.)
| | - Koshiro Tabata
- Department of Pathology, National Institute of Infectious Diseases, Tokyo 162-8640, Japan; (A.A.); (A.U.); (T.H.); ka-- (K.S.); (K.T.); (T.S.)
- Division of Molecular Pathobiology, International Institute for Zoonosis Control, Hokkaido University, Hokkaido 001-0020, Japan
| | - Masaru Yokoyama
- Center for Pathogen Genomics, National Institute of Infectious Diseases, Tokyo 208-0011, Japan; (M.Y.); (H.S.)
| | - Tadaki Suzuki
- Department of Pathology, National Institute of Infectious Diseases, Tokyo 162-8640, Japan; (A.A.); (A.U.); (T.H.); ka-- (K.S.); (K.T.); (T.S.)
| | - Hideki Hasegawa
- Center for Influenza and Respiratory Virus Research, National Institute of Infectious Diseases, Tokyo 208-0011, Japan; (Y.S.); (H.H.)
| | - Hironori Sato
- Center for Pathogen Genomics, National Institute of Infectious Diseases, Tokyo 208-0011, Japan; (M.Y.); (H.S.)
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