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Hermet P, Delache B, Herate C, Wolf E, Kivi G, Juronen E, Mumm K, Žusinaite E, Kainov D, Sankovski E, Virumäe K, Planken A, Merits A, Besaw JE, Yee AW, Morizumi T, Kim K, Kuo A, Berriche A, Dereuddre-Bosquet N, Sconosciuti Q, Naninck T, Relouzat F, Cavarelli M, Ustav M, Wilson D, Ernst OP, Männik A, LeGrand R, Ustav M. Broadly neutralizing humanized SARS-CoV-2 antibody binds to a conserved epitope on Spike and provides antiviral protection through inhalation-based delivery in non-human primates. PLoS Pathog 2023; 19:e1011532. [PMID: 37531329 PMCID: PMC10395824 DOI: 10.1371/journal.ppat.1011532] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Accepted: 07/03/2023] [Indexed: 08/04/2023] Open
Abstract
The COVID-19 pandemic represents a global challenge that has impacted and is expected to continue to impact the lives and health of people across the world for the foreseeable future. The rollout of vaccines has provided highly anticipated relief, but effective therapeutics are required to further reduce the risk and severity of infections. Monoclonal antibodies have been shown to be effective as therapeutics for SARS-CoV-2, but as new variants of concern (VoC) continue to emerge, their utility and use have waned due to limited or no efficacy against these variants. Furthermore, cumbersome systemic administration limits easy and broad access to such drugs. As well, concentrations of systemically administered antibodies in the mucosal epithelium, a primary site of initial infection, are dependent on neonatal Fc receptor mediated transport and require high drug concentrations. To reduce the viral load more effectively in the lung, we developed an inhalable formulation of a SARS-CoV-2 neutralizing antibody binding to a conserved epitope on the Spike protein, ensuring pan-neutralizing properties. Administration of this antibody via a vibrating mesh nebulization device retained antibody integrity and resulted in effective distribution of the antibody in the upper and lower respiratory tract of non-human primates (NHP). In comparison with intravenous administration, significantly higher antibody concentrations can be obtained in the lung, resulting in highly effective reduction in viral load post SARS-CoV-2 challenge. This approach may reduce the barriers of access and uptake of antibody therapeutics in real-world clinical settings and provide a more effective blueprint for targeting existing and potentially emerging respiratory tract viruses.
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Affiliation(s)
| | - Benoît Delache
- Université Paris-Saclay, Inserm, CEA, Center for Immunology of Viral, Auto-immune, Hematological and Bacterial Diseases (IMVA-HB/IDMIT); Fontenay-aux-Roses, France
| | - Cecile Herate
- Université Paris-Saclay, Inserm, CEA, Center for Immunology of Viral, Auto-immune, Hematological and Bacterial Diseases (IMVA-HB/IDMIT); Fontenay-aux-Roses, France
| | | | - Gaily Kivi
- Icosagen Cell Factory OÜ; Tartu, Estonia
| | | | - Karl Mumm
- Icosagen Cell Factory OÜ; Tartu, Estonia
| | | | | | | | | | | | | | - Jessica E Besaw
- Department of Biochemistry, University of Toronto; Toronto, Canada
| | - Ai Woon Yee
- Department of Biochemistry, University of Toronto; Toronto, Canada
| | | | - Kyumhyuk Kim
- Department of Biochemistry, University of Toronto; Toronto, Canada
| | - Anling Kuo
- Department of Biochemistry, University of Toronto; Toronto, Canada
| | - Asma Berriche
- Université Paris-Saclay, Inserm, CEA, Center for Immunology of Viral, Auto-immune, Hematological and Bacterial Diseases (IMVA-HB/IDMIT); Fontenay-aux-Roses, France
| | - Nathalie Dereuddre-Bosquet
- Université Paris-Saclay, Inserm, CEA, Center for Immunology of Viral, Auto-immune, Hematological and Bacterial Diseases (IMVA-HB/IDMIT); Fontenay-aux-Roses, France
| | - Quentin Sconosciuti
- Université Paris-Saclay, Inserm, CEA, Center for Immunology of Viral, Auto-immune, Hematological and Bacterial Diseases (IMVA-HB/IDMIT); Fontenay-aux-Roses, France
| | - Thibaut Naninck
- Université Paris-Saclay, Inserm, CEA, Center for Immunology of Viral, Auto-immune, Hematological and Bacterial Diseases (IMVA-HB/IDMIT); Fontenay-aux-Roses, France
| | - Francis Relouzat
- Université Paris-Saclay, Inserm, CEA, Center for Immunology of Viral, Auto-immune, Hematological and Bacterial Diseases (IMVA-HB/IDMIT); Fontenay-aux-Roses, France
| | - Mariangela Cavarelli
- Université Paris-Saclay, Inserm, CEA, Center for Immunology of Viral, Auto-immune, Hematological and Bacterial Diseases (IMVA-HB/IDMIT); Fontenay-aux-Roses, France
| | - Mart Ustav
- Icosagen Cell Factory OÜ; Tartu, Estonia
| | | | - Oliver P Ernst
- Department of Biochemistry, University of Toronto; Toronto, Canada
- Department of Molecular Genetics, University of Toronto; Toronto, Canada
| | | | - Roger LeGrand
- Université Paris-Saclay, Inserm, CEA, Center for Immunology of Viral, Auto-immune, Hematological and Bacterial Diseases (IMVA-HB/IDMIT); Fontenay-aux-Roses, France
| | - Mart Ustav
- Icosagen Cell Factory OÜ; Tartu, Estonia
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Kubo AL, Rausalu K, Savest N, Žusinaite E, Vasiliev G, Viirsalu M, Plamus T, Krumme A, Merits A, Bondarenko O. Antibacterial and Antiviral Effects of Ag, Cu and Zn Metals, Respective Nanoparticles and Filter Materials Thereof against Coronavirus SARS-CoV-2 and Influenza A Virus. Pharmaceutics 2022; 14:pharmaceutics14122549. [PMID: 36559043 PMCID: PMC9785359 DOI: 10.3390/pharmaceutics14122549] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Revised: 11/12/2022] [Accepted: 11/15/2022] [Indexed: 11/23/2022] Open
Abstract
Due to the high prevalence of infectious diseases and their concurrent outbreaks, there is a high interest in developing novel materials with antimicrobial properties. Antibacterial and antiviral properties of a range of metal-based nanoparticles (NPs) are a promising means to fight airborne diseases caused by viruses and bacteria. The aim of this study was to test antimicrobial metals and metal-based nanoparticles efficacy against three viruses, namely influenza A virus (H1N1; A/WSN/1933) and coronaviruses TGEV and SARS-CoV-2; and two bacteria, Escherichia coli and Staphylococcus aureus. The efficacy of ZnO, CuO, and Ag NPs and their respective metal salts, i.e., ZnSO4, CuSO4, and AgNO3, was evaluated in suspensions, and the compounds with the highest antiviral efficacy were chosen for incorporation into fibers of cellulose acetate (CA), using electrospinning to produce filter materials for face masks. Among the tested compounds, CuSO4 demonstrated the highest efficacy against influenza A virus and SARS-CoV-2 (1 h IC50 1.395 mg/L and 0.45 mg/L, respectively), followed by Zn salt and Ag salt. Therefore, Cu compounds were selected for incorporation into CA fibers to produce antiviral and antibacterial filter materials for face masks. CA fibers comprising CuSO4 decreased SARS-CoV-2 titer by 0.38 logarithms and influenza A virus titer by 1.08 logarithms after 5 min of contact; after 1 h of contact, SARS-COV-2 virus was completely inactivated. Developed CuO- and CuSO4-based filter materials also efficiently inactivated the bacteria Escherichia coli and Staphylococcus aureus. The metal NPs and respective metal salts were potent antibacterial and antiviral compounds that were successfully incorporated into the filter materials of face masks. New antibacterial and antiviral materials developed and characterized in this study are crucial in the context of the ongoing SARS-CoV-2 pandemic and beyond.
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Affiliation(s)
- Anna-Liisa Kubo
- Laboratory of Environmental Toxicology, National Institute of Chemical Physics and Biophysics, Akadeemia tee 23, 12618 Tallinn, Estonia
- Nanordica Medical OÜ, Vana-Lõuna 39a-7, 10134 Tallinn, Estonia
| | - Kai Rausalu
- Institute of Technology, University of Tartu, Nooruse 1, 50411 Tartu, Estonia
| | - Natalja Savest
- Laboratory of Polymers and Textile Technology, Department of Materials and Environmental Technology, Tallinn University of Technology, Ehitajate tee 5, 19086 Tallinn, Estonia
| | - Eva Žusinaite
- Institute of Technology, University of Tartu, Nooruse 1, 50411 Tartu, Estonia
| | - Grigory Vasiliev
- Laboratory of Environmental Toxicology, National Institute of Chemical Physics and Biophysics, Akadeemia tee 23, 12618 Tallinn, Estonia
- Nanordica Medical OÜ, Vana-Lõuna 39a-7, 10134 Tallinn, Estonia
| | - Mihkel Viirsalu
- Laboratory of Polymers and Textile Technology, Department of Materials and Environmental Technology, Tallinn University of Technology, Ehitajate tee 5, 19086 Tallinn, Estonia
| | - Tiia Plamus
- Laboratory of Polymers and Textile Technology, Department of Materials and Environmental Technology, Tallinn University of Technology, Ehitajate tee 5, 19086 Tallinn, Estonia
| | - Andres Krumme
- Laboratory of Polymers and Textile Technology, Department of Materials and Environmental Technology, Tallinn University of Technology, Ehitajate tee 5, 19086 Tallinn, Estonia
- Correspondence: (A.K.); (A.M.); (O.B.)
| | - Andres Merits
- Institute of Technology, University of Tartu, Nooruse 1, 50411 Tartu, Estonia
- Correspondence: (A.K.); (A.M.); (O.B.)
| | - Olesja Bondarenko
- Laboratory of Environmental Toxicology, National Institute of Chemical Physics and Biophysics, Akadeemia tee 23, 12618 Tallinn, Estonia
- Nanordica Medical OÜ, Vana-Lõuna 39a-7, 10134 Tallinn, Estonia
- Correspondence: (A.K.); (A.M.); (O.B.)
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3
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Naaber P, Tserel L, Kangro K, Punapart M, Sepp E, Jürjenson V, Kärner J, Haljasmägi L, Haljasorg U, Kuusk M, Sankovski E, Planken A, Ustav M, Žusinaite E, Gerhold JM, Kisand K, Peterson P. Protective antibodies and T cell responses to Omicron variant after the booster dose of BNT162b2 vaccine. Cell Rep Med 2022; 3:100716. [PMID: 35952669 PMCID: PMC9350667 DOI: 10.1016/j.xcrm.2022.100716] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2022] [Revised: 06/14/2022] [Accepted: 07/19/2022] [Indexed: 11/09/2022]
Abstract
The high number of mutations in the Omicron variant of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causes its immune escape. We report a longitudinal analysis of 111 vaccinated individuals for their antibody levels up to 6 months after the third dose of the BNT162b2 vaccine. After the third dose, the antibody levels decline but less than after the second dose. The booster dose remarkably increases the serum ability to block wild-type or Omicron variant spike protein’s receptor-binding domain (RBD) interaction with the angiotensin-converting enzyme 2 (ACE2) receptor, and these protective antibodies persist 3 months later. Three months after the booster dose, memory CD4+ and CD8+ T cells to the wild-type and Omicron variant are detectable in the majority of vaccinated individuals. Our data show that the third dose restores the high levels of blocking antibodies and enhances T cell responses to Omicron. After the third BNT162b2 dose, the antibody levels decline slower than after the second The protective antibodies persist for at least 3 months after the third dose 81% of individuals have T cell responses to Omicron at 3 months after third dose
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Kangro K, Kurašin M, Gildemann K, Sankovski E, Žusinaite E, Lello LS, Pert R, Kavak A, Poikalainen V, Lepasalu L, Kuusk M, Pau R, Piiskop S, Rom S, Oltjer R, Tiirik K, Kogermann K, Plaas M, Tiirats T, Aasmäe B, Plaas M, Mumm K, Krinka D, Talpsep E, Kadaja M, Gerhold JM, Planken A, Tover A, Merits A, Männik A, Ustav M, Ustav M. Bovine colostrum-derived antibodies against SARS-CoV-2 show great potential to serve as prophylactic agents. PLoS One 2022; 17:e0268806. [PMID: 35687549 PMCID: PMC9187060 DOI: 10.1371/journal.pone.0268806] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [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: 02/03/2022] [Accepted: 05/08/2022] [Indexed: 12/23/2022] Open
Abstract
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) continues to impose a serious burden on health systems globally. Despite worldwide vaccination, social distancing and wearing masks, the spread of the virus is ongoing. One of the mechanisms by which neutralizing antibodies (NAbs) block virus entry into cells encompasses interaction inhibition between the cell surface receptor angiotensin-converting enzyme 2 (ACE2) and the spike (S) protein of SARS-CoV-2. SARS-CoV-2-specific NAb development can be induced in the blood of cattle. Pregnant cows produce NAbs upon immunization, and antibodies move into the colostrum immediately before calving. Here, we immunized cows with SARS-CoV-2 S1 receptor binding domain (RBD) protein in proper adjuvant solutions, followed by one boost with SARS-CoV-2 trimeric S protein and purified immunoglobulins from colostrum. We demonstrate that this preparation indeed blocks the interaction between the trimeric S protein and ACE2 in different in vitro assays. Moreover, we describe the formulation of purified immunoglobulin preparation into a nasal spray. When administered to human subjects, the formulation persisted on the nasal mucosa for at least 4 hours, as determined by a clinical study. Therefore, we are presenting a solution that shows great potential to serve as a prophylactic agent against SARS-CoV-2 infection as an additional measure to vaccination and wearing masks. Moreover, our technology allows for rapid and versatile adaptation for preparing prophylactic treatments against other diseases using the defined characteristics of antibody movement into the colostrum.
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Affiliation(s)
- Kadri Kangro
- Icosagen Cell Factory OÜ, Õssu, Kambja vald, Tartumaa, Estonia
| | - Mihhail Kurašin
- Icosagen Cell Factory OÜ, Õssu, Kambja vald, Tartumaa, Estonia
| | - Kiira Gildemann
- Icosagen Cell Factory OÜ, Õssu, Kambja vald, Tartumaa, Estonia
| | - Eve Sankovski
- Icosagen Cell Factory OÜ, Õssu, Kambja vald, Tartumaa, Estonia
| | - Eva Žusinaite
- Institute of Technology, University of Tartu, Tartu, Estonia
| | | | - Raini Pert
- Icosagen Cell Factory OÜ, Õssu, Kambja vald, Tartumaa, Estonia
| | - Ants Kavak
- Department of Clinical Veterinary Medicine, Institute of Veterinary Medicine and Animal Sciences, Estonian University of Life Sciences, Tartu, Estonia
| | | | | | - Marilin Kuusk
- Icosagen Cell Factory OÜ, Õssu, Kambja vald, Tartumaa, Estonia
| | - Robin Pau
- Icosagen Cell Factory OÜ, Õssu, Kambja vald, Tartumaa, Estonia
| | | | - Siimu Rom
- Chemi-Pharm AS, Tänassilma, Harjumaa, Estonia
| | - Ruth Oltjer
- Chemi-Pharm AS, Tänassilma, Harjumaa, Estonia
| | - Kairi Tiirik
- Institute of Pharmacy, Faculty of Medicine, University of Tartu, Tartu, Estonia
| | - Karin Kogermann
- Institute of Pharmacy, Faculty of Medicine, University of Tartu, Tartu, Estonia
| | - Mario Plaas
- Institute of Biomedicine and Translational Medicine, Laboratory Animal Centre, University of Tartu, Tartu, Estonia
| | - Toomas Tiirats
- Department of Clinical Veterinary Medicine, Institute of Veterinary Medicine and Animal Sciences, Estonian University of Life Sciences, Tartu, Estonia
| | - Birgit Aasmäe
- Department of Clinical Veterinary Medicine, Institute of Veterinary Medicine and Animal Sciences, Estonian University of Life Sciences, Tartu, Estonia
| | - Mihkel Plaas
- Ear Clinic of Tartu University Hospital, Tartu, Estonia
| | - Karl Mumm
- Icosagen Cell Factory OÜ, Õssu, Kambja vald, Tartumaa, Estonia
| | - Dagni Krinka
- Icosagen AS, Õssu, Kambja vald, Tartumaa, Estonia
| | - Ene Talpsep
- Icosagen AS, Õssu, Kambja vald, Tartumaa, Estonia
| | - Meelis Kadaja
- Icosagen Cell Factory OÜ, Õssu, Kambja vald, Tartumaa, Estonia
| | | | - Anu Planken
- Icosagen Cell Factory OÜ, Õssu, Kambja vald, Tartumaa, Estonia
- North-Estonian Medical Centre, Tallinn, Estonia
| | - Andres Tover
- Icosagen Cell Factory OÜ, Õssu, Kambja vald, Tartumaa, Estonia
| | - Andres Merits
- Institute of Technology, University of Tartu, Tartu, Estonia
| | - Andres Männik
- Icosagen Cell Factory OÜ, Õssu, Kambja vald, Tartumaa, Estonia
| | - Mart Ustav
- Icosagen Cell Factory OÜ, Õssu, Kambja vald, Tartumaa, Estonia
- * E-mail: (MU); (MUJ)
| | - Mart Ustav
- Icosagen Cell Factory OÜ, Õssu, Kambja vald, Tartumaa, Estonia
- * E-mail: (MU); (MUJ)
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Teppor M, Žusinaite E, Karo-Astover L, Omler A, Rausalu K, Lulla V, Lulla A, Merits A. Semliki Forest Virus Chimeras with Functional Replicase Modules from Related Alphaviruses Survive by Adaptive Mutations in Functionally Important Hot Spots. J Virol 2021; 95:e0097321. [PMID: 34319778 PMCID: PMC8475518 DOI: 10.1128/jvi.00973-21] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [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: 06/14/2021] [Accepted: 07/19/2021] [Indexed: 11/20/2022] Open
Abstract
Alphaviruses (family Togaviridae) include both human pathogens such as chikungunya virus (CHIKV) and Sindbis virus (SINV) and model viruses such as Semliki Forest virus (SFV). The alphavirus positive-strand RNA genome is translated into nonstructural (ns) polyprotein(s) that are precursors for four nonstructural proteins (nsPs). The three-dimensional structures of nsP2 and the N-terminal 2/3 of nsP3 reveal that these proteins consist of several domains. Cleavage of the ns-polyprotein is performed by the strictly regulated protease activity of the nsP2 region. Processing results in the formation of a replicase complex that can be considered a network of functional modules. These modules work cooperatively and should perform the same task for each alphavirus. To investigate functional interactions between replicase components, we generated chimeras using the SFV genome as a backbone. The functional modules corresponding to different parts of nsP2 and nsP3 were swapped with their counterparts from CHIKV and SINV. Although some chimeras were nonfunctional, viruses harboring the CHIKV N-terminal domain of nsP2 or any domain of nsP3 were viable. Viruses harboring the protease part of nsP2, the full-length nsP2 of CHIKV, or the nsP3 macrodomain of SINV required adaptive mutations for functionality. Seven mutations that considerably improved the infectivity of the corresponding chimeric genomes affected functionally important hot spots recurrently highlighted in previous alphavirus studies. These data indicate that alphaviruses utilize a rather limited set of strategies to survive and adapt. Furthermore, functional analysis revealed that the disturbance of processing was the main defect resulting from chimeric alterations within the ns-polyprotein. IMPORTANCE Alphaviruses cause debilitating symptoms and have caused massive outbreaks. There are currently no approved antivirals or vaccines for treating these infections. Understanding the functions of alphavirus replicase proteins (nsPs) provides valuable information for both antiviral drug and vaccine development. The nsPs of all alphaviruses consist of similar functional modules; however, to what extent these are independent in functionality and thus interchangeable among homologous viruses is largely unknown. Homologous domain swapping was used to study the functioning of modules from nsP2 and nsP3 of other alphaviruses in the context of Semliki Forest virus. Most of the introduced substitutions resulted in defects in the processing of replicase precursors that were typically compensated by adaptive mutations that mapped to determinants of polyprotein processing. Understanding the principles of virus survival strategies and identifying hot spot mutations that permit virus adaptation highlight a route to the rapid development of attenuated viruses as potential live vaccine candidates.
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Affiliation(s)
- Mona Teppor
- Institute of Technology, University of Tartu, Tartu, Estonia
| | - Eva Žusinaite
- Institute of Technology, University of Tartu, Tartu, Estonia
| | | | - Ailar Omler
- Institute of Technology, University of Tartu, Tartu, Estonia
| | - Kai Rausalu
- Institute of Technology, University of Tartu, Tartu, Estonia
| | - Valeria Lulla
- Institute of Technology, University of Tartu, Tartu, Estonia
| | - Aleksei Lulla
- Institute of Technology, University of Tartu, Tartu, Estonia
| | - Andres Merits
- Institute of Technology, University of Tartu, Tartu, Estonia
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Jõgi P, Soeorg H, Ingerainen D, Soots M, Lättekivi F, Naaber P, Toompere K, Peterson P, Haljasmägi L, Žusinaite E, Vaas H, Pauskar M, Shablinskaja A, Kaarna K, Paluste H, Kisand K, Oona M, Janno R, Lutsar I. Prevalence of SARS-CoV-2 IgG antibodies and their association with clinical symptoms of COVID-19 in Estonia (KoroSero-EST-1 study). Vaccine 2021; 39:5376-5384. [PMID: 34393019 PMCID: PMC8339569 DOI: 10.1016/j.vaccine.2021.07.093] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [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: 11/02/2020] [Revised: 06/27/2021] [Accepted: 07/31/2021] [Indexed: 12/23/2022]
Abstract
PURPOSE In Estonia, during the first wave of COVID-19 total number of cases confirmed by PCR was 13.3/10,000, similar in most regions, including capital Tallinn, but in the hotspot of Estonian epidemic, an island Saaremaa, the cumulative incidence was 166.1/10,000. We aimed to determine the prevalence of SARS-CoV-2 IgG antibodies in these two regions, symptoms associated with infection and factors associated with antibody concentrations. METHODS Participants were selected using stratified (formed by age decades) random sampling and recruited by general practitioners. IgG or neutralizing antibodies were determined from sera by four assays. Symptoms associated with seropositivity were analyzed by multiple correspondence analysis, antibody concentrations by multiple linear regression. RESULTS Total of 3608 individual were invited and 1960 recruited from May 8 to July 31, 2020. Seroprevalence was 1.5% (95% confidence interval (CI) 0.9-2.5) and 6.3% (95% CI 5.0-7.9), infection fatality rate 0.1% (95% CI 0.0-0.2) and 1.3% (95% CI 0.4-2.1) in Tallinn and Saaremaa, respectively. Of seropositive subjects 19.2% (14/73) had acute respiratory illness. Fever, diarrhea and the absence of cough and runny nose were associated with seropositivity in individuals aged 50 or more years. IgG, but not neutralizing antibodies concentrations were higher if fever, difficulty breathing, shortness of breath, chest pain or diarrhea was present, or hospitalization required. CONCLUSION Similarly to other European countries the seroprevalence of SARS-CoV-2 in Estonia was low even in the hotspot region Saaremaa suggesting that majority of population is susceptible to SARS-CoV-2. Focusing only on respiratory symptoms may delay accurate diagnosis of SARS-CoV-2 infection.
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Affiliation(s)
- Piia Jõgi
- Children's Clinic of Tartu University Hospital, N. Lunini 6, 50406 Tartu, Estonia; Department of Pediatrics, Institute of Clinical Medicine, University of Tartu, L. Puusepa 8, 50406 Tartu, Estonia.
| | - Hiie Soeorg
- Department of Microbiology, Institute of Biomedicine and Translational Medicine, University of Tartu, Ravila 19, 50411 Tartu, Estonia
| | - Diana Ingerainen
- Family Doctor Center "Järveotsa", Õismäe tee 179, 13517 Tallinn, Estonia
| | - Mari Soots
- Family Doctor Center "Kuressaare", Aia 25a, 93815 Kuressaare, Estonia
| | - Freddy Lättekivi
- Department of Pathophysiology, Institute of Biomedicine and Translational Medicine, University of Tartu, Ravila 19, 50411 Tartu, Estonia; Development Centre, United Chancery Service, Tartu University Hospital, Puusepa 8, 50406 Tartu, Estonia
| | - Paul Naaber
- Department of Microbiology, Institute of Biomedicine and Translational Medicine, University of Tartu, Ravila 19, 50411 Tartu, Estonia; SYNLAB Estonia, Tallinn, Estonia
| | - Karolin Toompere
- Department of Epidemiology and Biostatistics, Institute of Family Medicine and Public Health, University of Tartu, Ravila 19, 50411 Tartu, Estonia
| | - Pärt Peterson
- Molecular Pathology, Institute of Biomedicine and Translational Medicine, University of Tartu, Ravila 19, 50411 Tartu, Estonia
| | - Liis Haljasmägi
- Molecular Pathology, Institute of Biomedicine and Translational Medicine, University of Tartu, Ravila 19, 50411 Tartu, Estonia
| | - Eva Žusinaite
- Institute of Technology, Faculty of Science and Technology, University of Tartu, Nooruse 1, 50411 Tartu, Estonia
| | - Hannes Vaas
- Children's Clinic of Tartu University Hospital, N. Lunini 6, 50406 Tartu, Estonia
| | - Merit Pauskar
- Department of Microbiology, Institute of Biomedicine and Translational Medicine, University of Tartu, Ravila 19, 50411 Tartu, Estonia
| | - Arina Shablinskaja
- Department of Microbiology, Institute of Biomedicine and Translational Medicine, University of Tartu, Ravila 19, 50411 Tartu, Estonia
| | - Katrin Kaarna
- Development Centre, United Chancery Service, Tartu University Hospital, Puusepa 8, 50406 Tartu, Estonia; Clinical Research Centre, Institute of Clinical Medicine, University of Tartu, Ravila 19, 50411 Tartu, Estonia
| | - Heli Paluste
- Ministry of Social Affairs, Republic of Estonia, Suur-Ameerika 1, 10122 Tallinn, Estonia
| | - Kai Kisand
- Molecular Pathology, Institute of Biomedicine and Translational Medicine, University of Tartu, Ravila 19, 50411 Tartu, Estonia
| | - Marje Oona
- Department of Family Medicine, Institute of Family Medicine and Public Health, University of Tartu, Ravila 19, 50411 Tartu, Estonia
| | - Riina Janno
- Development Centre, United Chancery Service, Tartu University Hospital, Puusepa 8, 50406 Tartu, Estonia
| | - Irja Lutsar
- Department of Microbiology, Institute of Biomedicine and Translational Medicine, University of Tartu, Ravila 19, 50411 Tartu, Estonia
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Selberg S, Žusinaite E, Herodes K, Seli N, Kankuri E, Merits A, Karelson M. HIV Replication Is Increased by RNA Methylation METTL3/METTL14/WTAP Complex Activators. ACS Omega 2021; 6:15957-15963. [PMID: 34179640 PMCID: PMC8223420 DOI: 10.1021/acsomega.1c01626] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Accepted: 06/03/2021] [Indexed: 05/04/2023]
Abstract
The N6-methyladenosine (m6A) modifications in both viral and host cell RNAs play an important role in HIV-1 virus genome transcription and virus replication. We demonstrate here that activators of the METTL3/METTL14/WTAP RNA methyltransferase complex enhance the production of virus particles in cells harboring HIV-1 provirus. In parallel, the amount of m6A residues in the host cell mRNA was increased in the presence of these activator compounds. Importantly, the m6A methylation of the HIV-1 RNA was also enhanced significantly (about 18%). The increase of virus replication by the small-molecule activators of the METTL3/METTL14/WTAP complex excludes them as potential anti-HIV-1 drug candidates. However, the compounds may be of large interest as activators for the latent HIV-1 provirus copies deposited in host cells' genome and the subsequent virus eradication by an antiviral compound.
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Affiliation(s)
- Simona Selberg
- Institute
of Chemistry, University of Tartu, Tartu 50411, Estonia
| | - Eva Žusinaite
- Institute
of Technology, University of Tartu, Tartu 50411, Estonia
| | - Koit Herodes
- Institute
of Chemistry, University of Tartu, Tartu 50411, Estonia
| | | | - Esko Kankuri
- Faculty
of Medicine, Department of Pharmacology, University of Helsinki, Helsinki 00014, Finland
| | - Andres Merits
- Institute
of Technology, University of Tartu, Tartu 50411, Estonia
- Email
| | - Mati Karelson
- Institute
of Chemistry, University of Tartu, Tartu 50411, Estonia
- Email
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8
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Ivanova L, Rausalu K, Ošeka M, Kananovich DG, Žusinaite E, Tammiku-Taul J, Lopp M, Merits A, Karelson M. Novel Analogues of the Chikungunya Virus Protease Inhibitor: Molecular Design, Synthesis, and Biological Evaluation. ACS Omega 2021; 6:10884-10896. [PMID: 34056242 PMCID: PMC8153904 DOI: 10.1021/acsomega.1c00625] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Accepted: 04/02/2021] [Indexed: 05/10/2023]
Abstract
The Chikungunya virus (CHIKV) is an arbovirus belonging to the genus Alphavirus of the Togaviridae family. CHIKV is transmitted by the mosquitoes and causes Chikungunya fever. CHIKV outbreaks have occurred in Africa, Asia, Europe, and the countries of Indian and Pacific Oceans. In 2013, CHIKV cases were registered for the first time in the Americas on the Caribbean islands. There is currently no vaccine to prevent or medicines to treat CHIKV infection. The CHIKV nonstructural protease (nsP2) is a promising potential target for the development of drugs against CHIKV infection because this protein is one of the key components of the viral replication complex and is involved in multiple steps of virus infection. In this work, novel analogues of the potential CHIKV nsP2 protease inhibitor, first reported by Das et al. in 2016, were identified using molecular modeling methods, synthesized, and evaluated in vitro. The optimization of the structure of the inhibitor allowed to increase the antiviral activity of the compound 2-10 times. The possible mechanism of action of the identified potential inhibitors of the CHIKV nsP2 protease was studied in detail using molecular dynamics (MD) simulations. According to the MD results, the most probable mechanism of action is the blocking of conformational changes in the nsP2 protease required for substrate recognition and binding.
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Affiliation(s)
- Larisa Ivanova
- Institute
of Chemistry, University of Tartu, Ravila 14A, 50411 Tartu, Estonia
| | - Kai Rausalu
- Institute
of Technology, University of Tartu, Nooruse 1, 50411 Tartu, Estonia
| | - Maksim Ošeka
- Department
of Chemistry and Biotechnology, Tallinn
University of Technology, Akadeemia Tee 15, 12618 Tallinn, Estonia
| | - Dzmitry G. Kananovich
- Department
of Chemistry and Biotechnology, Tallinn
University of Technology, Akadeemia Tee 15, 12618 Tallinn, Estonia
| | - Eva Žusinaite
- Institute
of Technology, University of Tartu, Nooruse 1, 50411 Tartu, Estonia
| | - Jaana Tammiku-Taul
- Institute
of Chemistry, University of Tartu, Ravila 14A, 50411 Tartu, Estonia
| | - Margus Lopp
- Department
of Chemistry and Biotechnology, Tallinn
University of Technology, Akadeemia Tee 15, 12618 Tallinn, Estonia
| | - Andres Merits
- Institute
of Technology, University of Tartu, Nooruse 1, 50411 Tartu, Estonia
| | - Mati Karelson
- Institute
of Chemistry, University of Tartu, Ravila 14A, 50411 Tartu, Estonia
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9
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Ivanova L, Rausalu K, Žusinaite E, Tammiku-Taul J, Merits A, Karelson M. 1,3-Thiazolbenzamide Derivatives as Chikungunya Virus nsP2 Protease Inhibitors. ACS Omega 2021; 6:5786-5794. [PMID: 33681617 PMCID: PMC7931429 DOI: 10.1021/acsomega.0c06191] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2020] [Accepted: 02/03/2021] [Indexed: 05/17/2023]
Abstract
Chikungunya fever results from an infection with Chikungunya virus (CHIKV, genus Alphavirus) that is prevalent in tropical regions and is spreading fast to temperate climates with documented outbreaks in Europe and the Americas. Currently, there are no available vaccines or antiviral drugs for prevention or treatment of Chikungunya fever. The nonstructural proteins (nsPs) of CHIKV responsible for virus replication are promising targets for the development of new antivirals. This study was attempted to find out new potential inhibitors of CHIKV nsP2 protease using the ligand-based drug design. Two compounds 10 and 10c, identified by molecular docking, showed antiviral activity against CHIKV with IC50 of 13.1 and 8.3 μM, respectively. Both compounds demonstrated the ability to inhibit the activity of nsP2 in a cell-free assay, and the impact of compound 10 on virus replication was confirmed by western blot. The molecular dynamics study of the interactions of compounds 10 and 10c with CHIKV nsP2 showed that a possible mechanism of action of these compounds is the blocking of the active site and the catalytic dyad of nsP2.
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Affiliation(s)
- Larisa Ivanova
- Institute
of Chemistry, University of Tartu, Ravila 14A, 50411 Tartu, Estonia
| | - Kai Rausalu
- Institute
of Technology, University of Tartu, Nooruse 1, 50411 Tartu, Estonia
| | - Eva Žusinaite
- Institute
of Technology, University of Tartu, Nooruse 1, 50411 Tartu, Estonia
| | - Jaana Tammiku-Taul
- Institute
of Chemistry, University of Tartu, Ravila 14A, 50411 Tartu, Estonia
| | - Andres Merits
- Institute
of Technology, University of Tartu, Nooruse 1, 50411 Tartu, Estonia
| | - Mati Karelson
- Institute
of Chemistry, University of Tartu, Ravila 14A, 50411 Tartu, Estonia
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10
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Mutso M, St John JA, Ling ZL, Burt FJ, Poo YS, Liu X, Žusinaite E, Grau GE, Hueston L, Merits A, King NJ, Ekberg JA, Mahalingam S. Basic insights into Zika virus infection of neuroglial and brain endothelial cells. J Gen Virol 2020; 101:622-634. [PMID: 32375993 PMCID: PMC7414445 DOI: 10.1099/jgv.0.001416] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [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: 12/16/2019] [Accepted: 03/24/2020] [Indexed: 12/31/2022] Open
Abstract
Zika virus (ZIKV) has recently emerged as an important human pathogen due to the strong evidence that it causes disease of the central nervous system, particularly microcephaly and Guillain-Barré syndrome. The pathogenesis of disease, including mechanisms of neuroinvasion, may include both invasion via the blood-brain barrier and via peripheral (including cranial) nerves. Cellular responses to infection are also poorly understood. This study characterizes the in vitro infection of laboratory-adapted ZIKV African MR766 and two Asian strains of (1) brain endothelial cells (hCMEC/D3 cell line) and (2) olfactory ensheathing cells (OECs) (the neuroglia populating cranial nerve I and the olfactory bulb; both human and mouse OEC lines) in comparison to kidney epithelial cells (Vero cells, in which ZIKV infection is well characterized). Readouts included infection kinetics, intracellular virus localization, viral persistence and cytokine responses. Although not as high as in Vero cells, viral titres exceeded 104 plaque-forming units (p.f.u.) ml-1 in the endothelial/neuroglial cell types, except hOECs. Despite these substantial titres, a relatively small proportion of neuroglial cells were primarily infected. Immunolabelling of infected cells revealed localization of the ZIKV envelope and NS3 proteins in the cytoplasm; NS3 staining overlapped with that of dsRNA replication intermediate and the endoplasmic reticulum (ER). Infected OECs and endothelial cells produced high levels of pro-inflammatory chemokines. Nevertheless, ZIKV was also able to establish persistent infection in hOEC and hCMEC/D3 cells. Taken together, these results provide basic insights into ZIKV infection of endothelial and neuroglial cells and will form the basis for further study of ZIKV disease mechanisms.
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Affiliation(s)
- Margit Mutso
- Institute for Glycomics, Griffith University, Gold Coast Campus, Southport 4222, Queensland, Australia
| | - James A. St John
- Institute for Glycomics, Griffith University, Gold Coast Campus, Southport 4222, Queensland, Australia
- Griffith Institute for Drug Discovery, Griffith University, Nathan 4111, Queensland, Australia
- Menzies Health Institute Queensland, Griffith University, Gold Coast Campus, Southport 4222, Queensland, Australia
| | - Zheng Lung Ling
- Discipline of Pathology, Bosch Institute, Marie Bashir Institute for Infectious diseases and Biosecurity, School of Medical Sciences, Sydney Medical School, University of Sydney, NSW 2006, Australia
| | - Felicity J. Burt
- National Health Laboratory Services, University of the Free State, Bloemfontein, South Africa
| | - Yee Suan Poo
- Institute for Glycomics, Griffith University, Gold Coast Campus, Southport 4222, Queensland, Australia
- Menzies Health Institute Queensland, Griffith University, Gold Coast Campus, Southport 4222, Queensland, Australia
| | - Xiang Liu
- Institute for Glycomics, Griffith University, Gold Coast Campus, Southport 4222, Queensland, Australia
- Menzies Health Institute Queensland, Griffith University, Gold Coast Campus, Southport 4222, Queensland, Australia
| | - Eva Žusinaite
- Institute of Technology, University of Tartu, Tartu, Estonia
| | - Georges E. Grau
- Vascular Immunology Unit, Discipline of Pathology, Sydney Medical School, University of Sydney, New South Wales 2050, Australia
| | - Linda Hueston
- Arbovirus Emerging Disease Unit, CIDMLS-ICPMR, Westmead Hospital, Westmead, NSW 2145, Australia
| | - Andres Merits
- Institute of Technology, University of Tartu, Tartu, Estonia
| | - Nicholas J.C. King
- Discipline of Pathology, Bosch Institute, Marie Bashir Institute for Infectious diseases and Biosecurity, School of Medical Sciences, Sydney Medical School, University of Sydney, NSW 2006, Australia
| | - Jenny A.K. Ekberg
- Menzies Health Institute Queensland, Griffith University, Gold Coast Campus, Southport 4222, Queensland, Australia
| | - Suresh Mahalingam
- Institute for Glycomics, Griffith University, Gold Coast Campus, Southport 4222, Queensland, Australia
- Menzies Health Institute Queensland, Griffith University, Gold Coast Campus, Southport 4222, Queensland, Australia
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11
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Meutiawati F, Bezemer B, Strating JRPM, Overheul GJ, Žusinaite E, van Kuppeveld FJM, van Cleef KWR, van Rij RP. Posaconazole inhibits dengue virus replication by targeting oxysterol-binding protein. Antiviral Res 2018; 157:68-79. [PMID: 29981375 DOI: 10.1016/j.antiviral.2018.06.017] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Revised: 06/08/2018] [Accepted: 06/30/2018] [Indexed: 11/30/2022]
Abstract
Dengue virus (DENV) is associated with an estimated 390 million infections per year, occurring across approximately 100 countries in tropical and sub-tropical regions. To date, there are no antiviral drugs or specific therapies to treat DENV infection. Posaconazole and itraconazole are potent antifungal drugs that inhibit ergosterol biosynthesis in fungal cells, but also target a number of human proteins. Here, we show that itraconazole and posaconazole have antiviral activity against DENV. Posaconazole inhibited replication of multiple serotypes of DENV and the related flavivirus Zika virus, and reduced viral RNA replication, but not translation of the viral genome. We used a combination of knockdown and drug sensitization assays to define the molecular target of posaconazole that mediates its antiviral activity. We found that knockdown of oxysterol-binding protein (OSBP) inhibited DENV replication. Moreover, knockdown of OSBP, but not other known targets of posaconazole, enhanced the inhibitory effect of posaconazole. Our findings imply OSBP as a potential target for the development of antiviral compounds against DENV.
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Affiliation(s)
- Febrina Meutiawati
- Department of Medical Microbiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, P.O. Box 9101, 6500 HB Nijmegen, The Netherlands; Radboudumc Center for Infectious Diseases, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Bodine Bezemer
- Department of Medical Microbiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, P.O. Box 9101, 6500 HB Nijmegen, The Netherlands; Radboudumc Center for Infectious Diseases, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Jeroen R P M Strating
- Virology Division, Department of Infectious Diseases & Immunology, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
| | - Gijs J Overheul
- Department of Medical Microbiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, P.O. Box 9101, 6500 HB Nijmegen, The Netherlands; Radboudumc Center for Infectious Diseases, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Eva Žusinaite
- Institute of Technology, University of Tartu, Tartu, Estonia
| | - Frank J M van Kuppeveld
- Virology Division, Department of Infectious Diseases & Immunology, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
| | - Koen W R van Cleef
- Department of Medical Microbiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, P.O. Box 9101, 6500 HB Nijmegen, The Netherlands; Radboudumc Center for Infectious Diseases, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Ronald P van Rij
- Department of Medical Microbiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, P.O. Box 9101, 6500 HB Nijmegen, The Netherlands; Radboudumc Center for Infectious Diseases, Radboud University Medical Center, Nijmegen, The Netherlands.
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12
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Mutso M, Saul S, Rausalu K, Susova O, Žusinaite E, Mahalingam S, Merits A. Reverse genetic system, genetically stable reporter viruses and packaged subgenomic replicon based on a Brazilian Zika virus isolate. J Gen Virol 2017; 98:2712-2724. [PMID: 29022864 DOI: 10.1099/jgv.0.000938] [Citation(s) in RCA: 74] [Impact Index Per Article: 10.6] [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: 02/01/2023] Open
Abstract
Zika virus (ZIKV, genus Flavivirus) has emerged as a major mosquito-transmitted human pathogen, with recent outbreaks associated with an increased incidence of neurological complications, particularly microcephaly and the Guillain-Barré syndrome. Because the virus has only very recently emerged as an important pathogen, research is being hampered by a lack of reliable molecular tools. Here we report an infectious cDNA (icDNA) clone for ZIKV isolate BeH819015 from Brazil, which was selected as representative of South American ZIKV isolated at early stages of the outbreak. icDNA clones were assembled from synthetic DNA fragments corresponding to the consensus sequence of the BeH819015 isolate. Virus rescued from the icDNA clone had properties identical to a natural ZIKV isolate from South America. Variants of the clone-derived virus, expressing nanoluciferase, enhanced green fluorescent or mCherry marker proteins in both mammalian and insect cells and being genetically stable for multiple in vitro passages, were obtained. A ZIKV subgenomic replicon, lacking a prM- and E glycoprotein encoding region and expressing a Gaussia luciferase marker, was constructed and shown to replicate both in mammalian and insect cells. In the presence of the Semliki Forest virus replicon, expressing ZIKV structural proteins, the ZIKV replicon was packaged into virus-replicon particles. Efficient reverse genetic systems, genetically stable marker viruses and packaged replicons offer significant improvements for biological studies of ZIKV infection and disease, as well as for the development of antiviral approaches.
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Affiliation(s)
- Margit Mutso
- Institute of Technology, University of Tartu, Tartu, Estonia.,Institute for Glycomics, Griffith University, Gold Coast Campus, Southport, 4222, Queensland, Australia
| | - Sirle Saul
- Institute of Technology, University of Tartu, Tartu, Estonia
| | - Kai Rausalu
- Institute of Technology, University of Tartu, Tartu, Estonia
| | - Olga Susova
- Blokhin Russian Cancer Research Center, Ministry of Health of the Russian Federation, Moscow, 115487, Russia
| | - Eva Žusinaite
- Institute of Technology, University of Tartu, Tartu, Estonia
| | - Suresh Mahalingam
- Institute for Glycomics, Griffith University, Gold Coast Campus, Southport, 4222, Queensland, Australia
| | - Andres Merits
- Institute of Technology, University of Tartu, Tartu, Estonia
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13
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Mutso M, Nikonov A, Pihlak A, Žusinaite E, Viru L, Selyutina A, Reintamm T, Kelve M, Saarma M, Karelson M, Merits A. RNA Interference-Guided Targeting of Hepatitis C Virus Replication with Antisense Locked Nucleic Acid-Based Oligonucleotides Containing 8-oxo-dG Modifications. PLoS One 2015; 10:e0128686. [PMID: 26039055 PMCID: PMC4454572 DOI: 10.1371/journal.pone.0128686] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [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: 01/13/2015] [Accepted: 04/29/2015] [Indexed: 12/23/2022] Open
Abstract
The inhibitory potency of an antisense oligonucleotide depends critically on its design and the accessibility of its target site. Here, we used an RNA interference-guided approach to select antisense oligonucleotide target sites in the coding region of the highly structured hepatitis C virus (HCV) RNA genome. We modified the conventional design of an antisense oligonucleotide containing locked nucleic acid (LNA) residues at its termini (LNA/DNA gapmer) by inserting 8-oxo-2'-deoxyguanosine (8-oxo-dG) residues into the central DNA region. Obtained compounds, designed with the aim to analyze the effects of 8-oxo-dG modifications on the antisense oligonucleotides, displayed a unique set of properties. Compared to conventional LNA/DNA gapmers, the melting temperatures of the duplexes formed by modified LNA/DNA gapmers and DNA or RNA targets were reduced by approximately 1.6-3.3°C per modification. Comparative transfection studies showed that small interfering RNA was the most potent HCV RNA replication inhibitor (effective concentration 50 (EC50): 0.13 nM), whereas isosequential standard and modified LNA/DNA gapmers were approximately 50-fold less efficient (EC50: 5.5 and 7.1 nM, respectively). However, the presence of 8-oxo-dG residues led to a more complete suppression of HCV replication in transfected cells. These modifications did not affect the efficiency of RNase H cleavage of antisense oligonucleotide:RNA duplexes but did alter specificity, triggering the appearance of multiple cleavage products. Moreover, the incorporation of 8-oxo-dG residues increased the stability of antisense oligonucleotides of different configurations in human serum.
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MESH Headings
- 8-Hydroxy-2'-Deoxyguanosine
- Base Pairing
- Cell Line, Tumor
- Deoxyguanosine/analogs & derivatives
- Deoxyguanosine/chemistry
- Genome, Viral
- Hepacivirus/genetics
- Hepacivirus/growth & development
- Hepatocytes/metabolism
- Hepatocytes/virology
- Humans
- Molecular Targeted Therapy
- Oligonucleotides/chemistry
- Oligonucleotides/metabolism
- Oligonucleotides, Antisense/chemical synthesis
- Oligonucleotides, Antisense/genetics
- Oligonucleotides, Antisense/metabolism
- RNA Cleavage
- RNA Interference
- RNA Stability
- RNA, Small Interfering/genetics
- RNA, Small Interfering/metabolism
- RNA, Viral/antagonists & inhibitors
- RNA, Viral/genetics
- RNA, Viral/metabolism
- Structure-Activity Relationship
- Virus Replication
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Affiliation(s)
- Margit Mutso
- Institute of Technology, University of Tartu, Tartu, Estonia
- GeneCode, Ltd., Tallinn, Estonia
| | - Andrei Nikonov
- Institute of Technology, University of Tartu, Tartu, Estonia
- GeneCode, Ltd., Tallinn, Estonia
| | | | - Eva Žusinaite
- Institute of Technology, University of Tartu, Tartu, Estonia
- GeneCode, Ltd., Tallinn, Estonia
| | - Liane Viru
- Institute of Technology, University of Tartu, Tartu, Estonia
- GeneCode, Ltd., Tallinn, Estonia
| | | | - Tõnu Reintamm
- GeneCode, Ltd., Tallinn, Estonia
- Department of Gene Technology, Tallinn University of Technology, Tallinn, Estonia
| | - Merike Kelve
- GeneCode, Ltd., Tallinn, Estonia
- Department of Gene Technology, Tallinn University of Technology, Tallinn, Estonia
| | - Mart Saarma
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Mati Karelson
- GeneCode, Ltd., Tallinn, Estonia
- Institute of Chemistry, University of Tartu, Tartu, Estonia
| | - Andres Merits
- Institute of Technology, University of Tartu, Tartu, Estonia
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14
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Kiiver K, Tagen I, Žusinaite E, Tamberg N, Fazakerley JK, Merits A. Properties of non-structural protein 1 of Semliki Forest virus and its interference with virus replication. J Gen Virol 2008; 89:1457-1466. [PMID: 18474562 PMCID: PMC2430273 DOI: 10.1099/vir.0.2008/000299-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Semliki Forest virus (SFV) non-structural protein 1 (nsP1) is a major component of the virus replicase complex. It has previously been studied in cells infected with virus or using transient or stable expression systems. To extend these studies, tetracycline-inducible stable cell lines expressing SFV nsP1 or its palmitoylation-negative mutant (nsP16D) were constructed. The levels of protein expression and the subcellular localization of nsP1 in induced cells were similar to those in virus-infected cells. The nsP1 expressed by stable, inducible cell lines or by SFV-infected HEK293 T-REx cells was a stable protein with a half-life of approximately 5 h. In contrast to SFV infection, induction of nsP1 expression had no detectable effect on cellular transcription, translation or viability. Induction of expression of nsP1 or nsP16D interfered with multiplication of SFV, typically resulting in a 5–10-fold reduction in virus yields. This reduction was not due to a decrease in the number of infected cells, indicating that nsP1 expression does not block virus entry or initiation of replication. Expression of nsP1 interfered with virus genomic RNA synthesis and delayed accumulation of viral subgenomic RNA translation products. Expression of nsP1 with a mutation in the palmitoylation site reduced synthesis of genomic and subgenomic RNAs and their products of translation, and this effect did not resolve with time. These results are in agreement with data published previously, suggesting a role for nsP1 in genomic RNA synthesis.
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Affiliation(s)
- Kaja Kiiver
- Estonian Biocentre, Tartu, Estonia.,Institute of Technology, University of Tartu, Tartu, Estonia
| | - Ingrid Tagen
- Estonian Biocentre, Tartu, Estonia.,Institute of Technology, University of Tartu, Tartu, Estonia
| | - Eva Žusinaite
- Institute of Technology, University of Tartu, Tartu, Estonia
| | - Nele Tamberg
- Institute of Technology, University of Tartu, Tartu, Estonia
| | - John K Fazakerley
- Centre for Infectious Diseases, College of Medicine and Veterinary Medicine, University of Edinburgh, Edinburgh, UK
| | - Andres Merits
- Estonian Biocentre, Tartu, Estonia.,Institute of Technology, University of Tartu, Tartu, Estonia
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15
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Žusinaite E, Tints K, Kiiver K, Spuul P, Karo-Astover L, Merits A, Sarand I. Mutations at the palmitoylation site of non-structural protein nsP1 of Semliki Forest virus attenuate virus replication and cause accumulation of compensatory mutations. J Gen Virol 2007; 88:1977-1985. [PMID: 17554031 PMCID: PMC2271122 DOI: 10.1099/vir.0.82865-0] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [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] [Indexed: 12/13/2022] Open
Abstract
The replicase of Semliki Forest virus (SFV) consists of four non-structural proteins, designated nsP1–4, and is bound to cellular membranes via an amphipathic peptide and palmitoylated cysteine residues of nsP1. It was found that mutations preventing nsP1 palmitoylation also attenuated virus replication. The replacement of these cysteines by alanines, or their deletion, abolished virus viability, possibly due to disruption of interactions between nsP1 and nsP4, which is the catalytic subunit of the replicase. However, during a single infection cycle, the ability of the virus to replicate was restored due to accumulation of second-site mutations in nsP1. These mutations led to the restoration of nsP1–nsP4 interaction, but did not restore the palmitoylation of nsP1. The proteins with palmitoylation-site mutations, as well as those harbouring compensatory mutations in addition to palmitoylation-site mutations, were enzymically active and localized, at least in part, on the plasma membrane of transfected cells. Interestingly, deletion of 7 aa including the palmitoylation site of nsP1 had a relatively mild effect on virus viability and no significant impact on nsP1–nsP4 interaction. Similarly, the change of cysteine to alanine at the palmitoylation site of nsP1 of Sindbis virus had only a mild effect on virus replication. Taken together, these findings indicate that nsP1 palmitoylation as such is not the factor determining the ability to bind to cellular membranes and form a functional replicase complex. Instead, these abilities may be linked to the three-dimensional structure of nsP1 and the capability of nsP1 to interact with other components of the viral replicase complex.
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Affiliation(s)
- Eva Žusinaite
- Institute of Molecular and Cell Biology, University of Tartu, Nooruse 1, 50411 Tartu, Estonia
| | - Kairit Tints
- Institute of Molecular and Cell Biology, University of Tartu, Nooruse 1, 50411 Tartu, Estonia
- Estonian Biocentre, Riia Street 23, 51010 Tartu, Estonia
| | - Kaja Kiiver
- Institute of Molecular and Cell Biology, University of Tartu, Nooruse 1, 50411 Tartu, Estonia
- Estonian Biocentre, Riia Street 23, 51010 Tartu, Estonia
| | - Pirjo Spuul
- Institute of Biotechnology, University of Helsinki, 00014 Helsinki, Finland
| | - Liis Karo-Astover
- Institute of Molecular and Cell Biology, University of Tartu, Nooruse 1, 50411 Tartu, Estonia
- Estonian Biocentre, Riia Street 23, 51010 Tartu, Estonia
| | - Andres Merits
- Institute of Molecular and Cell Biology, University of Tartu, Nooruse 1, 50411 Tartu, Estonia
| | - Inga Sarand
- Estonian Biocentre, Riia Street 23, 51010 Tartu, Estonia
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