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  1. Article ; Online: Construction of Fosmid-based SARS-CoV-2 replicons for antiviral drug screening and replication analyses in biosafety level 2 facilities.

    Takazawa, Shunta / Kotaki, Tomohiro / Nakamura, Satsuki / Utsubo, Chie / Kameoka, Masanori

    Virus research

    2023  Volume 334, Page(s) 199176

    Abstract: The coronavirus disease 2019 (COVID-19) pandemic, caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), has necessitated the global development of countermeasures since its outbreak. However, current therapeutics and vaccines to stop ... ...

    Abstract The coronavirus disease 2019 (COVID-19) pandemic, caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), has necessitated the global development of countermeasures since its outbreak. However, current therapeutics and vaccines to stop the pandemic are insufficient and this is mainly because of the emergence of resistant variants, which requires the urgent development of new countermeasures, such as antiviral drugs. Replicons, self-replicating RNAs that do not produce virions, are a promising system for this purpose because they safely recreate viral replication, enabling antiviral screening in biosafety level (BSL)-2 facilities. We herein constructed three pCC2Fos-based RNA replicons lacking some open reading frames (ORF) of SARS-CoV-2: the Δorf2-8, Δorf2.4, and Δorf2 replicons, and validated their replication in Huh-7 cells. The functionalities of the Δorf2-8 and Δorf2.4 replicons for antiviral drug screening were also confirmed. We conducted puromycin selection following the construction of the Δorf2.4-puro replicon by inserting a puromycin-resistant gene into the Δorf2.4 replicon. We observed the more sustained replication of the Δorf2.4-puro replicon by puromycin pressure. The present results will contribute to the establishment of a safe and useful replicon system for analyzing SARS-CoV-2 replication mechanisms as well as the development of novel antiviral drugs in BSL-2 facilities.
    MeSH term(s) Humans ; Antiviral Agents/pharmacology ; SARS-CoV-2/genetics ; COVID-19/genetics ; Drug Evaluation, Preclinical ; Containment of Biohazards ; Virus Replication ; Replicon ; Puromycin/pharmacology
    Chemical Substances Antiviral Agents ; Puromycin (4A6ZS6Q2CL)
    Language English
    Publishing date 2023-07-22
    Publishing country Netherlands
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 605780-9
    ISSN 1872-7492 ; 0168-1702
    ISSN (online) 1872-7492
    ISSN 0168-1702
    DOI 10.1016/j.virusres.2023.199176
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  2. Article: Japanese Encephalitis DNA Vaccines with Epitope Modification Reduce the Induction of Cross-Reactive Antibodies against Dengue Virus and Antibody-Dependent Enhancement of Dengue Virus Infection.

    Kotaki, Tomohiro / Nagai, Yurie / Yamanaka, Atsushi / Konishi, Eiji / Kameoka, Masanori

    Vaccines

    2022  Volume 10, Issue 9

    Abstract: Infection with viruses belonging to the ... ...

    Abstract Infection with viruses belonging to the genus
    Language English
    Publishing date 2022-08-28
    Publishing country Switzerland
    Document type Journal Article
    ZDB-ID 2703319-3
    ISSN 2076-393X
    ISSN 2076-393X
    DOI 10.3390/vaccines10091411
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  3. Article ; Online: Further Characterization of the Antiviral Transmembrane Protein MARCH8.

    Tada, Takuya / Zhang, Yanzhao / Kong, Dechuan / Tanaka, Michiko / Yao, Weitong / Kameoka, Masanori / Ueno, Takamasa / Fujita, Hideaki / Tokunaga, Kenzo

    Cells

    2024  Volume 13, Issue 8

    Abstract: The cellular transmembrane protein MARCH8 impedes the incorporation of various viral envelope glycoproteins, such as the HIV-1 envelope glycoprotein (Env) and vesicular stomatitis virus G-glycoprotein (VSV-G), into virions by downregulating them from the ...

    Abstract The cellular transmembrane protein MARCH8 impedes the incorporation of various viral envelope glycoproteins, such as the HIV-1 envelope glycoprotein (Env) and vesicular stomatitis virus G-glycoprotein (VSV-G), into virions by downregulating them from the surface of virus-producing cells. This downregulation significantly reduces the efficiency of virus infection. In this study, we aimed to further characterize this host protein by investigating its species specificity and the domains responsible for its antiviral activity, as well as its ability to inhibit cell-to-cell HIV-1 infection. We found that the antiviral function of MARCH8 is well conserved in the rhesus macaque, mouse, and bovine versions. The RING-CH domains of these versions are functionally important for inhibiting HIV-1 Env and VSV-G-pseudovirus infection, whereas tyrosine motifs are crucial for the former only, consistent with findings in human MARCH8. Through analysis of chimeric proteins between MARCH8 and non-antiviral MARCH3, we determined that both the N-terminal and C-terminal cytoplasmic tails, as well as presumably the N-terminal transmembrane domain, of MARCH8 are critical for its antiviral activity. Notably, we found that MARCH8 is unable to block cell-to-cell HIV-1 infection, likely due to its insufficient downregulation of Env. These findings offer further insights into understanding the biology of this antiviral transmembrane protein.
    MeSH term(s) Humans ; Animals ; HIV-1 ; Membrane Proteins/metabolism ; HEK293 Cells ; Ubiquitin-Protein Ligases/metabolism ; Mice ; Cattle ; Macaca mulatta ; HIV Infections/virology ; HIV Infections/metabolism ; Antiviral Agents/pharmacology ; Protein Domains ; env Gene Products, Human Immunodeficiency Virus/metabolism
    Chemical Substances Membrane Proteins ; MARCHF8 protein, human (EC 2.3.2.27) ; Ubiquitin-Protein Ligases (EC 2.3.2.27) ; Antiviral Agents ; env Gene Products, Human Immunodeficiency Virus
    Language English
    Publishing date 2024-04-17
    Publishing country Switzerland
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 2661518-6
    ISSN 2073-4409 ; 2073-4409
    ISSN (online) 2073-4409
    ISSN 2073-4409
    DOI 10.3390/cells13080698
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  4. Article ; Online: Construction of Fosmid-based SARS-CoV-2 replicons for antiviral drug screening and replication analyses in biosafety level 2 facilities

    Takazawa, Shunta / Kotaki, Tomohiro / Nakamura, Satsuki / Utsubo, Chie / Kameoka, Masanori

    bioRxiv

    Abstract: The coronavirus disease 2019 (COVID-19) pandemic, caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), has necessitated the global development of countermeasures since its outbreak. However, current therapeutics and vaccines to stop ... ...

    Abstract The coronavirus disease 2019 (COVID-19) pandemic, caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), has necessitated the global development of countermeasures since its outbreak. However, current therapeutics and vaccines to stop the pandemic are insufficient and this is mainly because of the emergence of resistant variants, which requires the urgent development of new countermeasures, such as antiviral drugs. Replicons, self-replicating RNAs that do not produce virions, are a promising system for this purpose because they safely recreate viral replication, enabling antiviral screening in biosafety level (BSL)-2 facilities. We herein constructed three pCC2Fos-based RNA replicons lacking some open reading frames (ORF) of SARS-CoV-2: the Dorf2-8, Δorf2.4, and Δorf2 replicons, and validated their replication in Huh-7 cells. The functionalities of the Δorf2-8 and Δorf2.4 replicons for antiviral drug screening were also confirmed. We conducted puromycin selection following the construction of the Δorf2.4-puro replicon by inserting a puromycin-resistant gene into the Δorf2.4 replicon. We observed the more sustained replication of the Δorf2.4-puro replicon by puromycin pressure. The present results will contribute to the establishment of a safe and useful replicon system for analyzing SARS-CoV-2 replication mechanisms as well as the development of novel antiviral drugs in BSL-2 facilities.
    Keywords covid19
    Language English
    Publishing date 2023-02-16
    Publisher Cold Spring Harbor Laboratory
    Document type Article ; Online
    DOI 10.1101/2023.02.15.528742
    Database COVID19

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  5. Article ; Online: Multiplexed

    Ophinni, Youdiil / Miki, Sayaka / Hayashi, Yoshitake / Kameoka, Masanori

    Viruses

    2020  Volume 12, Issue 11

    Abstract: HIV-1 cure strategy by means of proviral knock-out using CRISPR-Cas9 has been hampered by the emergence of viral resistance against the targeting guide RNA (gRNA). Here, we proposed multiple, concentrated gRNA attacks against HIV-1 regulatory genes to ... ...

    Abstract HIV-1 cure strategy by means of proviral knock-out using CRISPR-Cas9 has been hampered by the emergence of viral resistance against the targeting guide RNA (gRNA). Here, we proposed multiple, concentrated gRNA attacks against HIV-1 regulatory genes to block viral escape. The T cell line were transduced with single and multiple gRNAs targeting HIV-1
    MeSH term(s) CRISPR-Cas Systems ; Cell Line ; Gene Editing ; Genetic Vectors ; Genome, Viral ; HIV-1/immunology ; HIV-1/physiology ; Humans ; Lentivirus/genetics ; Mutation ; Proviruses/genetics ; RNA, Guide, CRISPR-Cas Systems/genetics ; T-Lymphocytes/immunology ; T-Lymphocytes/virology ; Virus Replication/genetics ; tat Gene Products, Human Immunodeficiency Virus/antagonists & inhibitors ; tat Gene Products, Human Immunodeficiency Virus/genetics
    Chemical Substances RNA, Guide, CRISPR-Cas Systems ; tat Gene Products, Human Immunodeficiency Virus
    Language English
    Publishing date 2020-10-28
    Publishing country Switzerland
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 2516098-9
    ISSN 1999-4915 ; 1999-4915
    ISSN (online) 1999-4915
    ISSN 1999-4915
    DOI 10.3390/v12111223
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  6. Article ; Online: A potent neutralizing mouse monoclonal antibody specific to dengue virus type 1 Mochizuki strain recognized a novel epitope around the N-67 glycan on the envelope protein: A possible explanation of dengue virus evolution regarding the acquisition of N-67 glycan.

    Kotaki, Tomohiro / Yamanaka, Atsushi / Konishi, Eiji / Kameoka, Masanori

    Virus research

    2020  Volume 294, Page(s) 198278

    Abstract: The analysis of neutralizing epitope of dengue virus (DENV) is important for the development of an effective dengue vaccine. A potent neutralizing mouse monoclonal antibody named 7F4 was previously reported and, here, we further analyzed the detailed ... ...

    Abstract The analysis of neutralizing epitope of dengue virus (DENV) is important for the development of an effective dengue vaccine. A potent neutralizing mouse monoclonal antibody named 7F4 was previously reported and, here, we further analyzed the detailed epitope of this antibody. 7F4 recognized a novel conformational epitope close to the N-67 glycan on the envelope protein. This antibody was specific to the DENV that lacks N-67 glycan, including the Mochizuki strain. Interestingly, the Mochizuki strain acquired N-67 glycan by 7F4 selective pressure. Considering that most of the currently circulating DENVs possess N-67 glycan, DENVs may have evolved to escape from antibodies targeting 7F4 epitope, suggesting the potency of this neutralizing epitope. In addition, this study demonstrated the existence of the epitopes close to 7F4 epitope and their crucial role in neutralization. In conclusion, the epitopes close to the N-67 glycan are attractive targets for the dengue vaccine antigen. Further analysis of this epitope is warranted.
    MeSH term(s) Animals ; Antibodies, Monoclonal ; Antibodies, Neutralizing ; Antibodies, Viral ; Dengue ; Dengue Vaccines ; Dengue Virus/genetics ; Epitopes ; Mice ; Polysaccharides ; Viral Envelope Proteins/genetics
    Chemical Substances Antibodies, Monoclonal ; Antibodies, Neutralizing ; Antibodies, Viral ; Dengue Vaccines ; Epitopes ; Polysaccharides ; Viral Envelope Proteins
    Language English
    Publishing date 2020-12-31
    Publishing country Netherlands
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 605780-9
    ISSN 1872-7492 ; 0168-1702
    ISSN (online) 1872-7492
    ISSN 0168-1702
    DOI 10.1016/j.virusres.2020.198278
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  7. Article ; Online: A PCR amplicon-based SARS-CoV-2 replicon for antiviral evaluation.

    Kotaki, Tomohiro / Xie, Xuping / Shi, Pei-Yong / Kameoka, Masanori

    Scientific reports

    2021  Volume 11, Issue 1, Page(s) 2229

    Abstract: The development of specific antiviral compounds to SARS-CoV-2 is an urgent task. One of the obstacles for the antiviral development is the requirement of biocontainment because infectious SARS-CoV-2 must be handled in a biosafety level-3 laboratory. ... ...

    Abstract The development of specific antiviral compounds to SARS-CoV-2 is an urgent task. One of the obstacles for the antiviral development is the requirement of biocontainment because infectious SARS-CoV-2 must be handled in a biosafety level-3 laboratory. Replicon, a non-infectious self-replicative viral RNA, could be a safe and effective tool for antiviral evaluation. Herein, we generated a PCR-based SARS-CoV-2 replicon. Eight fragments covering the entire SARS-CoV-2 genome except S, E, and M genes were amplified with HiBiT-tag sequence by PCR. The amplicons were ligated and in vitro transcribed to RNA. The cells electroporated with the replicon RNA showed more than 3000 times higher luminescence than MOCK control cells at 24 h post-electroporation, indicating robust translation and RNA replication of the replicon. The replication was drastically inhibited by remdesivir, an RNA polymerase inhibitor for SARS-CoV-2. The IC
    MeSH term(s) Adenosine Monophosphate/analogs & derivatives ; Adenosine Monophosphate/pharmacology ; Alanine/analogs & derivatives ; Alanine/pharmacology ; Animals ; Antiviral Agents/pharmacology ; CHO Cells ; COVID-19 ; Chlorocebus aethiops ; Cricetulus ; Drug Design ; Drug Evaluation, Preclinical ; Electroporation ; Genome, Viral ; HEK293 Cells ; Humans ; Inhibitory Concentration 50 ; Kinetics ; Open Reading Frames ; Polymerase Chain Reaction ; RNA, Viral ; RNA-Dependent RNA Polymerase ; SARS-CoV-2/drug effects ; SARS-CoV-2/physiology ; Untranslated Regions ; Vero Cells ; Virion ; Virus Replication/drug effects
    Chemical Substances Antiviral Agents ; RNA, Viral ; Untranslated Regions ; remdesivir (3QKI37EEHE) ; Adenosine Monophosphate (415SHH325A) ; RNA-Dependent RNA Polymerase (EC 2.7.7.48) ; Alanine (OF5P57N2ZX)
    Language English
    Publishing date 2021-01-26
    Publishing country England
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 2615211-3
    ISSN 2045-2322 ; 2045-2322
    ISSN (online) 2045-2322
    ISSN 2045-2322
    DOI 10.1038/s41598-021-82055-0
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  8. Article: Multiplexed tat-Targeting CRISPR-Cas9 Protects T Cells from Acute HIV-1 Infection with Inhibition of Viral Escape

    Ophinni, Youdiil / Miki, Sayaka / Hayashi, Yoshitake / Kameoka, Masanori

    Viruses. 2020 Oct. 28, v. 12, no. 11

    2020  

    Abstract: HIV-1 cure strategy by means of proviral knock-out using CRISPR-Cas9 has been hampered by the emergence of viral resistance against the targeting guide RNA (gRNA). Here, we proposed multiple, concentrated gRNA attacks against HIV-1 regulatory genes to ... ...

    Abstract HIV-1 cure strategy by means of proviral knock-out using CRISPR-Cas9 has been hampered by the emergence of viral resistance against the targeting guide RNA (gRNA). Here, we proposed multiple, concentrated gRNA attacks against HIV-1 regulatory genes to block viral escape. The T cell line were transduced with single and multiple gRNAs targeting HIV-1 tat and rev using lentiviral-based CRISPR-Cas9, followed by replicative HIV-1NL₄₋₃ challenge in vitro. Viral p24 rebound was observed for almost all gRNAs, but multiplexing three tat-targeting gRNAs maintained p24 suppression and cell viability, indicating the inhibition of viral escape. Multiplexed tat gRNAs inhibited acute viral replication in the 2nd round of infection, abolished cell-associated transmission to unprotected T cells, and maintained protection through 45 days, post-infection (dpi) after a higher dose of HIV-1 infection. Finally, we describe here for the first time the assembly of all-in-one lentiviral vectors containing three and six gRNAs targeting tat and rev. A single-vector tat-targeting construct shows non-inferiority to the tat-targeting multi-vector in low-dose HIV-1 infection. We conclude that Cas9-induced, DNA repair-mediated mutations in tat are sufficiently deleterious and deplete HIV-1 fitness, and multiplexed disruption of tat further limits the possibility of an escape mutant arising, thus elevating the potential of CRISPR-Cas9 to achieve a long-term HIV-1 cure.
    Keywords CRISPR-Cas systems ; DNA ; HIV infections ; Human immunodeficiency virus 1 ; RNA ; T-lymphocytes ; cell lines ; cell viability ; mutants ; mutation ; regulator genes ; virus replication
    Language English
    Dates of publication 2020-1028
    Publishing place Multidisciplinary Digital Publishing Institute
    Document type Article
    ZDB-ID 2516098-9
    ISSN 1999-4915
    ISSN 1999-4915
    DOI 10.3390/v12111223
    Database NAL-Catalogue (AGRICOLA)

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  9. Article ; Online: Inactivation of SARS-CoV-2 and influenza A virus by dry fogging hypochlorous acid solution and hydrogen peroxide solution.

    Urushidani, Masahiro / Kawayoshi, Akira / Kotaki, Tomohiro / Saeki, Keiichi / Mori, Yasuko / Kameoka, Masanori

    PloS one

    2022  Volume 17, Issue 4, Page(s) e0261802

    Abstract: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative agent of coronavirus disease 2019 (COVID-19), is transmitted mainly by droplet or aerosol infection; however, it may also be transmitted by contact infection. SARS-CoV-2 that ... ...

    Abstract Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative agent of coronavirus disease 2019 (COVID-19), is transmitted mainly by droplet or aerosol infection; however, it may also be transmitted by contact infection. SARS-CoV-2 that adheres to environmental surfaces remains infectious for several days. We herein attempted to inactivate SARS-CoV-2 and influenza A virus adhering to an environmental surface by dry fogging hypochlorous acid solution and hydrogen peroxide solution. SARS-CoV-2 and influenza virus were air-dried on plastic plates and placed into a test chamber for inactivation by the dry fogging of these disinfectants. The results obtained showed that the dry fogging of hypochlorous acid solution and hydrogen peroxide solution inactivated SARS-CoV-2 and influenza A virus in CT value (the product of the disinfectant concentration and contact time)-dependent manners. SARS-CoV-2 was more resistant to the virucidal effects of aerosolized hypochlorous acid solution and hydrogen peroxide solution than influenza A virus; therefore, higher concentrations of disinfectants or longer contact times were required to inactivate SARS-CoV-2 than influenza A virus. The present results provide important information for the development of a strategy that inactivates SARS-CoV-2 and influenza A virus on environmental surfaces by spatial fogging.
    MeSH term(s) COVID-19 ; Disinfectants/pharmacology ; Humans ; Hydrogen Peroxide/pharmacology ; Hypochlorous Acid/pharmacology ; Influenza A virus ; SARS-CoV-2 ; Virus Inactivation
    Chemical Substances Disinfectants ; Hypochlorous Acid (712K4CDC10) ; Hydrogen Peroxide (BBX060AN9V)
    Language English
    Publishing date 2022-04-07
    Publishing country United States
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 2267670-3
    ISSN 1932-6203 ; 1932-6203
    ISSN (online) 1932-6203
    ISSN 1932-6203
    DOI 10.1371/journal.pone.0261802
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  10. Article ; Online: Construction and evaluation of a self-replicative RNA vaccine against SARS-CoV-2 using yellow fever virus replicon.

    Nakamura, Akina / Kotaki, Tomohiro / Nagai, Yurie / Takazawa, Shunta / Tokunaga, Kenzo / Kameoka, Masanori

    PloS one

    2022  Volume 17, Issue 10, Page(s) e0274829

    Abstract: The coronavirus disease 2019 (COVID-19) pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection is a global threat. To forestall the pandemic, developing safe and effective vaccines is necessary. Because of the rapid ... ...

    Abstract The coronavirus disease 2019 (COVID-19) pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection is a global threat. To forestall the pandemic, developing safe and effective vaccines is necessary. Because of the rapid production and little effect on the host genome, mRNA vaccines are attractive, but they have a relatively low immune response after a single dose. Replicon RNA (repRNA) is a promising vaccine platform for safety and efficacy. RepRNA vaccine encodes not only antigen genes but also the genes necessary for RNA replication. Thus, repRNA is self-replicative and can play the role of an adjuvant by itself, which elicits robust immunity. This study constructed and evaluated a repRNA vaccine in which the gene encoding the spike (S) protein of SARS-CoV-2 was inserted into a replicon of yellow fever virus 17D strain. Upon electroporation of this repRNA into baby hamster kidney cells, the S protein and yellow fever virus protein were co-expressed. Additionally, the self-replication ability of repRNA vaccine was confirmed using qRT-PCR, demonstrating its potency as a vaccine. Immunization of C57BL/6 mice with 1 μg of the repRNA vaccine induced specific T-cell responses but not antibody responses. Notably, the T-cell response induced by the repRNA vaccine was significantly higher than that induced by the nonreplicative RNA vaccine in our experimental model. In the future, it is of the essence to optimize vaccine administration methods and improve S protein expression, like protection of repRNA by nanoparticles and evasion of innate immunity of the host to enhance the immune-inducing ability of the repRNA vaccine.
    MeSH term(s) Mice ; Animals ; Humans ; SARS-CoV-2/genetics ; COVID-19 Vaccines ; Yellow fever virus ; COVID-19/prevention & control ; Mice, Inbred C57BL ; Vaccines, Synthetic/genetics ; Replicon ; RNA/genetics ; Spike Glycoprotein, Coronavirus ; Antibodies, Viral ; Antibodies, Neutralizing ; mRNA Vaccines
    Chemical Substances COVID-19 Vaccines ; Vaccines, Synthetic ; RNA (63231-63-0) ; Spike Glycoprotein, Coronavirus ; Antibodies, Viral ; Antibodies, Neutralizing ; spike protein, SARS-CoV-2
    Language English
    Publishing date 2022-10-20
    Publishing country United States
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 2267670-3
    ISSN 1932-6203 ; 1932-6203
    ISSN (online) 1932-6203
    ISSN 1932-6203
    DOI 10.1371/journal.pone.0274829
    Database MEDical Literature Analysis and Retrieval System OnLINE

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