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Bonneux B, Jacoby E, Ceconi M, Stobbelaar K, Delputte P, Herschke F. Direct-acting antivirals for RSV treatment, a review. Antiviral Res 2024; 229:105948. [PMID: 38972604 DOI: 10.1016/j.antiviral.2024.105948] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2024] [Revised: 06/20/2024] [Accepted: 06/24/2024] [Indexed: 07/09/2024]
Abstract
Respiratory syncytial virus (RSV) causes respiratory disease and complications in infants, the elderly and the immunocompromised. While three vaccines and two prophylactic monoclonal antibodies are now available, only one antiviral, ribavirin, is currently approved for treatment. This review aims to summarize the current state of treatments directly targeting RSV. Two major viral processes are attractive for RSV-specific antiviral drug discovery and development as they play essential roles in the viral cycle: the entry/fusion process carried out by the fusion protein and the replication/transcription process carried out by the polymerase complex constituted of the L, P, N and M2-1 proteins. For each viral target resistance mutations to small molecules of different chemotypes seem to delineate definite binding pockets in the fusion proteins and in the large proteins. Elucidating the mechanism of action of these inhibitors thus helps to understand how the fusion and polymerase complexes execute their functions. While many inhibitors have been studied, few are currently in clinical development for RSV treatment: one is in phase III, three in phase II and two in phase I. Progression was halted for many others because of strategic decisions, low enrollment, safety, but also lack of efficacy. Lessons can be learnt from the halted programs to increase the success rate of the treatments currently in development.
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Affiliation(s)
- Brecht Bonneux
- Laboratory for Microbiology, Parasitology and Hygiene, University of Antwerp, Universiteitsbaan 1, 2610, Wilrijk, Belgium; Janssen Pharmaceutica NV, Turnhoutseweg 30, 2340, Beerse, Belgium
| | - Edgar Jacoby
- Janssen Pharmaceutica NV, Turnhoutseweg 30, 2340, Beerse, Belgium
| | - Martina Ceconi
- Laboratory for Microbiology, Parasitology and Hygiene, University of Antwerp, Universiteitsbaan 1, 2610, Wilrijk, Belgium
| | - Kim Stobbelaar
- Janssen Pharmaceutica NV, Turnhoutseweg 30, 2340, Beerse, Belgium
| | - Peter Delputte
- Laboratory for Microbiology, Parasitology and Hygiene, University of Antwerp, Universiteitsbaan 1, 2610, Wilrijk, Belgium.
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2
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Kleiner VA, Fearns R. How does the polymerase of non-segmented negative strand RNA viruses commit to transcription or genome replication? J Virol 2024; 98:e0033224. [PMID: 39078194 PMCID: PMC11334523 DOI: 10.1128/jvi.00332-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/31/2024] Open
Abstract
The Mononegavirales, or non-segmented negative-sense RNA viruses (nsNSVs), includes significant human pathogens, such as respiratory syncytial virus, parainfluenza virus, measles virus, Ebola virus, and rabies virus. Although these viruses differ widely in their pathogenic properties, they are united by each having a genome consisting of a single strand of negative-sense RNA. Consistent with their shared genome structure, the nsNSVs have evolved similar ways to transcribe their genome into mRNAs and replicate it to produce new genomes. Importantly, both mRNA transcription and genome replication are performed by a single virus-encoded polymerase. A fundamental and intriguing question is: how does the nsNSV polymerase commit to being either an mRNA transcriptase or a replicase? The polymerase must become committed to one process or the other either before it interacts with the genome template or in its initial interactions with the promoter sequence at the 3´ end of the genomic RNA. This review examines the biochemical, molecular biology, and structural biology data regarding the first steps of transcription and RNA replication that have been gathered over several decades for different families of nsNSVs. These findings are discussed in relation to possible models that could explain how an nsNSV polymerase initiates and commits to either transcription or genome replication.
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Affiliation(s)
- Victoria A. Kleiner
- Department of Virology, Immunology & Microbiology, Boston University Chobanian & Avedisian School of Medicine, Boston, Massachusetts, USA
| | - Rachel Fearns
- Department of Virology, Immunology & Microbiology, Boston University Chobanian & Avedisian School of Medicine, Boston, Massachusetts, USA
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3
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Bonneux B, Shareef A, Tcherniuk S, Anson B, de Bruyn S, Verheyen N, Thys K, Conceição-Neto N, Van Ginderen M, Kwanten L, Ysebaert N, Vranckx L, Peeters E, Lanckacker E, Gallup JM, Sitthicharoenchai P, Alnajjar S, Ackermann MR, Adhikary S, Bhaumik A, Patrick A, Fung A, Sutto-Ortiz P, Decroly E, Mason SW, Lançois D, Deval J, Jin Z, Eléouët JF, Fearns R, Koul A, Roymans D, Rigaux P, Herschke F. JNJ-7184, a respiratory syncytial virus inhibitor targeting the connector domain of the viral polymerase. Antiviral Res 2024; 227:105907. [PMID: 38772503 DOI: 10.1016/j.antiviral.2024.105907] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2024] [Revised: 05/08/2024] [Accepted: 05/12/2024] [Indexed: 05/23/2024]
Abstract
Respiratory syncytial virus (RSV) can cause pulmonary complications in infants, elderly and immunocompromised patients. While two vaccines and two prophylactic monoclonal antibodies are now available, treatment options are still needed. JNJ-7184 is a non-nucleoside inhibitor of the RSV-Large (L) polymerase, displaying potent inhibition of both RSV-A and -B strains. Resistance selection and hydrogen-deuterium exchange experiments suggest JNJ-7184 binds RSV-L in the connector domain. JNJ-7184 prevents RSV replication and transcription by inhibiting initiation or early elongation. JNJ-7184 is effective in air-liquid interface cultures and therapeutically in neonatal lambs, acting to drastically reverse the appearance of lung pathology.
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Affiliation(s)
- Brecht Bonneux
- Laboratory for Microbiology, Parasitology and Hygiene, University of Antwerp, Universiteitsbaan 1, 2610 Wilrijk, Belgium; Janssen Pharmaceutica NV, Turnhoutseweg 30, 2340 Beerse, Belgium
| | - Afzaal Shareef
- Department of Virology, Immunology & Microbiology, National Emerging Infectious Diseases Laboratories, Boston University Chobanian & Avedisian School of Medicine, Boston, MA 02118, USA
| | - Sergey Tcherniuk
- Unité de Virologie et Immunologie Moléculaires (VIM, UMR892), INRAE, Université Paris-Saclay, 78352 Jouy-en-Josas, France
| | - Brandon Anson
- Janssen Research & Development LLC, Spring House (PA 19477) And Brisbane (CA 94005), USA
| | - Suzanne de Bruyn
- Janssen Pharmaceutica NV, Turnhoutseweg 30, 2340 Beerse, Belgium
| | - Nick Verheyen
- Janssen Pharmaceutica NV, Turnhoutseweg 30, 2340 Beerse, Belgium
| | - Kim Thys
- Janssen Pharmaceutica NV, Turnhoutseweg 30, 2340 Beerse, Belgium
| | | | | | - Leen Kwanten
- Janssen Pharmaceutica NV, Turnhoutseweg 30, 2340 Beerse, Belgium
| | - Nina Ysebaert
- Janssen Pharmaceutica NV, Turnhoutseweg 30, 2340 Beerse, Belgium
| | - Luc Vranckx
- Janssen Pharmaceutica NV, Turnhoutseweg 30, 2340 Beerse, Belgium
| | - Elien Peeters
- Janssen Pharmaceutica NV, Turnhoutseweg 30, 2340 Beerse, Belgium
| | - Ellen Lanckacker
- Janssen Pharmaceutica NV, Turnhoutseweg 30, 2340 Beerse, Belgium
| | | | | | | | | | - Suraj Adhikary
- Janssen Research & Development LLC, Spring House (PA 19477) And Brisbane (CA 94005), USA
| | - Anusarka Bhaumik
- Janssen Research & Development LLC, Spring House (PA 19477) And Brisbane (CA 94005), USA
| | - Aaron Patrick
- Janssen Research & Development LLC, Spring House (PA 19477) And Brisbane (CA 94005), USA
| | - Amy Fung
- Janssen Research & Development LLC, Spring House (PA 19477) And Brisbane (CA 94005), USA
| | - Priscila Sutto-Ortiz
- AFMB, Aix-Marseille University, CNRS UMR 7257, 163 Avenue de Luminy, Marseille, France
| | - Etienne Decroly
- AFMB, Aix-Marseille University, CNRS UMR 7257, 163 Avenue de Luminy, Marseille, France
| | - Stephen W Mason
- Janssen Research & Development LLC, Spring House (PA 19477) And Brisbane (CA 94005), USA
| | | | - Jerome Deval
- Janssen Research & Development LLC, Spring House (PA 19477) And Brisbane (CA 94005), USA
| | - Zhinan Jin
- Janssen Research & Development LLC, Spring House (PA 19477) And Brisbane (CA 94005), USA
| | - Jean-François Eléouët
- Unité de Virologie et Immunologie Moléculaires (VIM, UMR892), INRAE, Université Paris-Saclay, 78352 Jouy-en-Josas, France
| | - Rachel Fearns
- Department of Virology, Immunology & Microbiology, National Emerging Infectious Diseases Laboratories, Boston University Chobanian & Avedisian School of Medicine, Boston, MA 02118, USA
| | - Anil Koul
- Janssen Pharmaceutica NV, Turnhoutseweg 30, 2340 Beerse, Belgium.
| | - Dirk Roymans
- Janssen Pharmaceutica NV, Turnhoutseweg 30, 2340 Beerse, Belgium
| | - Peter Rigaux
- Janssen Pharmaceutica NV, Turnhoutseweg 30, 2340 Beerse, Belgium
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4
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Cox RM, Plemper RK. Design and Execution of In Vitro Polymerase Assays for Measles Virus and Related Mononegaviruses. Methods Mol Biol 2024; 2808:19-33. [PMID: 38743360 DOI: 10.1007/978-1-0716-3870-5_3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/16/2024]
Abstract
Morbilliviruses such as measles virus (MeV) are responsible for major morbidity and mortality worldwide, despite the availability of an effective vaccine and global vaccination campaigns. MeV belongs to the mononegavirus order of viral pathogens that store their genetic information in non-segmented negative polarity RNA genomes. Genome replication and viral gene expression are carried out by a virus-encoded RNA-dependent RNA polymerase (RdRP) complex that has no immediate host cell analog. To better understand the organization and regulation of the viral RdRP and mechanistically characterize antiviral candidates, biochemical RdRP assays have been developed that employ purified recombinant polymerase complexes and synthetic RNA templates to monitor the initiation of RNA synthesis and RNA elongation in vitro. In this article, we will discuss strategies for the efficient expression and preparation of mononegavirus polymerase complexes, provide detailed protocols for the execution and optimization of RdRP assays, evaluate alternative options for the choice of template and detection system, and describe the application of the assay for the characterization of inhibitor candidates. Although MeV RdRP assays are the focus of this article, the general strategies and experimental approaches are readily transferable to related viruses in the mononegavirus order.
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Affiliation(s)
- Robert M Cox
- Center for Translational Antiviral Research, Institute for Biomedical Sciences, Georgia State University, Atlanta, GA, USA
| | - Richard K Plemper
- Center for Translational Antiviral Research, Institute for Biomedical Sciences, Georgia State University, Atlanta, GA, USA.
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5
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Huang G, Hucek D, Cierpicki T, Grembecka J. Applications of oxetanes in drug discovery and medicinal chemistry. Eur J Med Chem 2023; 261:115802. [PMID: 37713805 DOI: 10.1016/j.ejmech.2023.115802] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2023] [Revised: 09/06/2023] [Accepted: 09/07/2023] [Indexed: 09/17/2023]
Abstract
The compact and versatile oxetane motifs have gained significant attention in drug discovery and medicinal chemistry campaigns. This review presents an overview of the diverse applications of oxetanes in clinical and preclinical drug candidates targeting various human diseases, including cancer, viral infections, autoimmune disorders, neurodegenerative conditions, metabolic disorders, and others. Special attention is given to biologically active oxetane-containing compounds and their disease-related targets, such as kinases, epigenetic and non-epigenetic enzymes, and receptors. The review also details the effect of the oxetane motif on important properties, including aqueous solubility, lipophilicity, pKa, P-glycoprotein (P-gp) efflux, metabolic stability, conformational preferences, toxicity profiles (e.g., cytochrome P450 (CYP) suppression and human ether-a-go-go related gene (hERG) inhibition), pharmacokinetic (PK) properties, potency, and target selectivity. We anticipate that this work will provide valuable insights that can drive future discoveries of novel bioactive oxetane-containing small molecules, enabling their effective application in combating a wide range of human diseases.
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Affiliation(s)
- Guang Huang
- Department of Pathology, University of Michigan, Ann Arbor, MI, 48109, USA.
| | - Devon Hucek
- Department of Pathology, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Tomasz Cierpicki
- Department of Pathology, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Jolanta Grembecka
- Department of Pathology, University of Michigan, Ann Arbor, MI, 48109, USA
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6
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Yu X, Abeywickrema P, Bonneux B, Behera I, Anson B, Jacoby E, Fung A, Adhikary S, Bhaumik A, Carbajo RJ, De Bruyn S, Miller R, Patrick A, Pham Q, Piassek M, Verheyen N, Shareef A, Sutto-Ortiz P, Ysebaert N, Van Vlijmen H, Jonckers THM, Herschke F, McLellan JS, Decroly E, Fearns R, Grosse S, Roymans D, Sharma S, Rigaux P, Jin Z. Structural and mechanistic insights into the inhibition of respiratory syncytial virus polymerase by a non-nucleoside inhibitor. Commun Biol 2023; 6:1074. [PMID: 37865687 PMCID: PMC10590419 DOI: 10.1038/s42003-023-05451-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2023] [Accepted: 10/11/2023] [Indexed: 10/23/2023] Open
Abstract
The respiratory syncytial virus polymerase complex, consisting of the polymerase (L) and phosphoprotein (P), catalyzes nucleotide polymerization, cap addition, and cap methylation via the RNA dependent RNA polymerase, capping, and Methyltransferase domains on L. Several nucleoside and non-nucleoside inhibitors have been reported to inhibit this polymerase complex, but the structural details of the exact inhibitor-polymerase interactions have been lacking. Here, we report a non-nucleoside inhibitor JNJ-8003 with sub-nanomolar inhibition potency in both antiviral and polymerase assays. Our 2.9 Å resolution cryo-EM structure revealed that JNJ-8003 binds to an induced-fit pocket on the capping domain, with multiple interactions consistent with its tight binding and resistance mutation profile. The minigenome and gel-based de novo RNA synthesis and primer extension assays demonstrated that JNJ-8003 inhibited nucleotide polymerization at the early stages of RNA transcription and replication. Our results support that JNJ-8003 binding modulates a functional interplay between the capping and RdRp domains, and this molecular insight could accelerate the design of broad-spectrum antiviral drugs.
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Affiliation(s)
- Xiaodi Yu
- Johnson & Johnson Innovative Medicine, Spring House, Pennsylvania, PA, 19477, USA.
| | - Pravien Abeywickrema
- Johnson & Johnson Innovative Medicine, Spring House, Pennsylvania, PA, 19477, USA
| | - Brecht Bonneux
- Janssen Infectious Diseases and Vaccines, 2340, Beerse, Belgium
- University of Antwerp, Antwerp, Belgium
| | - Ishani Behera
- Johnson & Johnson Innovative Medicine, Brisbane, CA, 94005, USA
| | - Brandon Anson
- Johnson & Johnson Innovative Medicine, Brisbane, CA, 94005, USA
| | - Edgar Jacoby
- Johnson & Johnson Innovative Medicine, Beerse, Belgium
| | - Amy Fung
- Johnson & Johnson Innovative Medicine, Brisbane, CA, 94005, USA
| | - Suraj Adhikary
- Johnson & Johnson Innovative Medicine, Spring House, Pennsylvania, PA, 19477, USA
| | - Anusarka Bhaumik
- Johnson & Johnson Innovative Medicine, Spring House, Pennsylvania, PA, 19477, USA
| | - Rodrigo J Carbajo
- Johnson & Johnson Innovative Medicine, Janssen-Cilag, Discovery Chemistry S.A. Río Jarama, 75A, 45007, Toledo, Spain
| | | | - Robyn Miller
- Johnson & Johnson Innovative Medicine, Spring House, Pennsylvania, PA, 19477, USA
| | - Aaron Patrick
- Johnson & Johnson Innovative Medicine, Spring House, Pennsylvania, PA, 19477, USA
| | - Quyen Pham
- Johnson & Johnson Innovative Medicine, Brisbane, CA, 94005, USA
| | - Madison Piassek
- Johnson & Johnson Innovative Medicine, Spring House, Pennsylvania, PA, 19477, USA
| | - Nick Verheyen
- Janssen Infectious Diseases and Vaccines, 2340, Beerse, Belgium
| | - Afzaal Shareef
- Department of Microbiology, National Emerging Infectious Diseases Laboratories, Boston University Chobanian & Avedisian School of Medicine, Boston, MA, 02118, USA
| | | | - Nina Ysebaert
- Janssen Infectious Diseases and Vaccines, 2340, Beerse, Belgium
| | | | | | | | - Jason S McLellan
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX, 78712, USA
| | - Etienne Decroly
- Aix Marseille Université, CNRS, AFMB, UMR 7257, Marseille, France
| | - Rachel Fearns
- Department of Microbiology, National Emerging Infectious Diseases Laboratories, Boston University Chobanian & Avedisian School of Medicine, Boston, MA, 02118, USA
| | | | - Dirk Roymans
- Janssen Infectious Diseases and Vaccines, 2340, Beerse, Belgium
| | - Sujata Sharma
- Johnson & Johnson Innovative Medicine, Spring House, Pennsylvania, PA, 19477, USA
| | - Peter Rigaux
- Janssen Infectious Diseases and Vaccines, 2340, Beerse, Belgium
| | - Zhinan Jin
- Johnson & Johnson Innovative Medicine, Brisbane, CA, 94005, USA.
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7
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Kleiner VA, O Fischmann T, Howe JA, Beshore DC, Eddins MJ, Hou Y, Mayhood T, Klein D, Nahas DD, Lucas BJ, Xi H, Murray E, Ma DY, Getty K, Fearns R. Conserved allosteric inhibitory site on the respiratory syncytial virus and human metapneumovirus RNA-dependent RNA polymerases. Commun Biol 2023; 6:649. [PMID: 37337079 DOI: 10.1038/s42003-023-04990-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Accepted: 05/26/2023] [Indexed: 06/21/2023] Open
Abstract
Respiratory syncytial virus (RSV) and human metapneumovirus (HMPV) are related RNA viruses responsible for severe respiratory infections and resulting disease in infants, elderly, and immunocompromised adults1-3. Therapeutic small molecule inhibitors that bind to the RSV polymerase and inhibit viral replication are being developed, but their binding sites and molecular mechanisms of action remain largely unknown4. Here we report a conserved allosteric inhibitory site identified on the L polymerase proteins of RSV and HMPV that can be targeted by a dual-specificity, non-nucleoside inhibitor, termed MRK-1. Cryo-EM structures of the inhibitor in complexes with truncated RSV and full-length HMPV polymerase proteins provide a structural understanding of how MRK-1 is active against both viruses. Functional analyses indicate that MRK-1 inhibits conformational changes necessary for the polymerase to engage in RNA synthesis initiation and to transition into an elongation mode. Competition studies reveal that the MRK-1 binding pocket is distinct from that of a capping inhibitor with an overlapping resistance profile, suggesting that the polymerase conformation bound by MRK-1 may be distinct from that involved in mRNA capping. These findings should facilitate optimization of dual RSV and HMPV replication inhibitors and provide insights into the molecular mechanisms underlying their polymerase activities.
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Affiliation(s)
- Victoria A Kleiner
- Department of Virology, Immunology & Microbiology, National Emerging Infectious Diseases Laboratories, Boston University Chobanian and Avedisian School of Medicine, Boston, MA, USA
| | | | | | | | | | - Yan Hou
- MRL, Merck & Co., Inc., Rahway, NJ, USA
| | | | | | | | | | - He Xi
- MRL, Merck & Co., Inc., Rahway, NJ, USA
| | | | | | | | - Rachel Fearns
- Department of Virology, Immunology & Microbiology, National Emerging Infectious Diseases Laboratories, Boston University Chobanian and Avedisian School of Medicine, Boston, MA, USA.
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8
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Xu E, Park S, Calderon J, Cao D, Liang B. In Silico Identification and In Vitro Validation of Repurposed Compounds Targeting the RSV Polymerase. Microorganisms 2023; 11:1608. [PMID: 37375110 DOI: 10.3390/microorganisms11061608] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2023] [Revised: 06/14/2023] [Accepted: 06/14/2023] [Indexed: 06/29/2023] Open
Abstract
Respiratory Syncytial Virus (RSV) is the top cause of infant hospitalization globally, with no effective treatments available. Researchers have sought small molecules to target the RNA-dependent RNA Polymerase (RdRP) of RSV, which is essential for replication and transcription. Based on the cryo-EM structure of the RSV polymerase, in silico computational analysis including molecular docking and the protein-ligand simulation of a database, including 6554 molecules, is currently undergoing phases 1-4 of clinical trials and has resulted in the top ten repurposed compound candidates against the RSV polymerase, including Micafungin, Totrombopag, and Verubecestat. We performed the same procedure to evaluate 18 small molecules from previous studies and chose the top four compounds for comparison. Among the top identified repurposed compounds, Micafungin, an antifungal medication, showed significant inhibition and binding affinity improvements over current inhibitors such as ALS-8112 and Ribavirin. We also validated Micafungin's inhibition of the RSV RdRP using an in vitro transcription assay. These findings contribute to RSV drug development and hold promise for broad-spectrum antivirals targeting the non-segmented negative-sense (NNS) RNA viral polymerases, including those of rabies (RABV) and Ebola (EBOV).
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Affiliation(s)
- Eric Xu
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Seohyun Park
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Juan Calderon
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Dongdong Cao
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Bo Liang
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322, USA
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9
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Sutto-Ortiz P, Eléouët JF, Ferron F, Decroly E. Biochemistry of the Respiratory Syncytial Virus L Protein Embedding RNA Polymerase and Capping Activities. Viruses 2023; 15:v15020341. [PMID: 36851554 PMCID: PMC9960070 DOI: 10.3390/v15020341] [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: 11/30/2022] [Revised: 01/12/2023] [Accepted: 01/21/2023] [Indexed: 01/27/2023] Open
Abstract
The human respiratory syncytial virus (RSV) is a negative-sense, single-stranded RNA virus. It is the major cause of severe acute lower respiratory tract infection in infants, the elderly population, and immunocompromised individuals. There is still no approved vaccine or antiviral treatment against RSV disease, but new monoclonal prophylactic antibodies are yet to be commercialized, and clinical trials are in progress. Hence, urgent efforts are needed to develop efficient therapeutic treatments. RSV RNA synthesis comprises viral transcription and replication that are catalyzed by the large protein (L) in coordination with the phosphoprotein polymerase cofactor (P), the nucleoprotein (N), and the M2-1 transcription factor. The replication/transcription is orchestrated by the L protein, which contains three conserved enzymatic domains: the RNA-dependent RNA polymerase (RdRp), the polyribonucleotidyl transferase (PRNTase or capping), and the methyltransferase (MTase) domain. These activities are essential for the RSV replicative cycle and are thus considered as attractive targets for the development of therapeutic agents. In this review, we summarize recent findings about RSV L domains structure that highlight how the enzymatic activities of RSV L domains are interconnected, discuss the most relevant and recent antivirals developments that target the replication/transcription complex, and conclude with a perspective on identified knowledge gaps that enable new research directions.
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Affiliation(s)
| | - Jean-François Eléouët
- Unité de Virologie et Immunologie Moléculaires, INRAE, Université Paris Saclay, F78350 Jouy en Josas, France
| | - François Ferron
- Aix Marseille Université, CNRS, AFMB, UMR, 7257 Marseille, France
- European Virus Bioinformatics Center, Leutragraben 1, 07743 Jena, Germany
| | - Etienne Decroly
- Aix Marseille Université, CNRS, AFMB, UMR, 7257 Marseille, France
- Correspondence:
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10
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Cao D, Gooneratne I, Mera C, Vy J, Royal M, Huang B, Park Y, Manjunath A, Liang B. Analysis of Template Variations on RNA Synthesis by Respiratory Syncytial Virus Polymerase. Viruses 2022; 15:47. [PMID: 36680087 PMCID: PMC9863079 DOI: 10.3390/v15010047] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2022] [Revised: 12/18/2022] [Accepted: 12/21/2022] [Indexed: 12/28/2022] Open
Abstract
Respiratory syncytial virus (RSV) is a significant threat to infants and elderly individuals globally. Currently, there are no effective therapies or treatments for RSV infection because of an insufficient understanding of the RSV viral machinery. In this study, we investigated the effects of the template variations on RNA synthesis by the RSV polymerase through in vitro RNA synthesis assays. We confirmed the previously reported back-priming activity of the RSV polymerase, which is likely due to the secondary structure of the RNA template. We found that the expansion of the hairpin loop size of the RNA template abolishes the RSV polymerase back-priming activity. At the same time, it seemingly does not affect the de novo RNA synthesis activities of the RSV polymerase. Interestingly, our results show that the RSV polymerase also has a new primer-based terminal extension activity that adds nucleotides to the template and primer in a nonspecific manner. We also mapped the impact of the RNA 5' chemical group on its mobility in a urea-denaturing RNA gel shift assay. Overall, these results enhance our knowledge about the RNA synthesis processes of the RSV polymerase and may guide future therapeutic efforts to develop effective antiviral drugs for RSV treatment.
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Affiliation(s)
| | | | | | | | | | | | | | | | - Bo Liang
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322, USA
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11
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Cheng N, Jiang N, Fu Y, Xu Z, Peng X, Yu J, Cen S, Wang Y, Zhang G, Zheng Y, He J. The mechanism and pharmacodynamics of 2-((1H-indol-3-yl)thio/sulfinyl)-N-pheny acetamide derivative as a novel inhibitor against human respiratory syncytial virus. J Enzyme Inhib Med Chem 2022; 37:2598-2604. [PMID: 36131622 PMCID: PMC9518288 DOI: 10.1080/14756366.2022.2123804] [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] [Indexed: 12/01/2022] Open
Abstract
Human respiratory syncytial virus (RSV) is a leading cause of lower respiratory tract infection worldwide. Until now, there are no licenced vaccines or effective antiviral drugs against RSV infections. In our previous work, we found 2-((1H-indol-3-yl)thio/sulfinyl)-N-pheny acetamide derivatives (4-49 C and 1-HB-63) being a novel inhibitor against RSV in vitro. Here, we explored the underlying mechanism of 2-((1H-indol-3-yl)thio/sulfinyl)-N-pheny acetamide derivatives to inhibit RSV replication in vitro and disclosed that 4–49 C worked as the inhibitor of membrane fusion and 1-HB-63 functioned at the stage of RSV genome replication/transcription. Yet, both of them could not inhibit RSV infection of BALB/c mice by using RSV-Luc, in vivo imaging and RT-qPCR analyses, for which it may be due to the fast metabolism in vivo. Our work suggests that further structural modification and optimisation of 2-((1H-indol-3-yl) thio/sulfinyl)-N-pheny acetamide derivative are needed to obtain drug candidates with effective anti-RSV activities in vivo.
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Affiliation(s)
- Ningning Cheng
- College of Life Sciences and Bioengineering, Beijing Jiaotong University, Beijing, China
| | - Nan Jiang
- College of Life Sciences and Bioengineering, Beijing Jiaotong University, Beijing, China
| | - Yuanhui Fu
- College of Life Sciences and Bioengineering, Beijing Jiaotong University, Beijing, China
| | - Zhuxin Xu
- College of Life Sciences and Bioengineering, Beijing Jiaotong University, Beijing, China
| | - Xianglei Peng
- College of Life Sciences and Bioengineering, Beijing Jiaotong University, Beijing, China
| | - Jiemei Yu
- College of Life Sciences and Bioengineering, Beijing Jiaotong University, Beijing, China
| | - Shan Cen
- Institute of Medicinal Biotechnology, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, China
| | - Yucheng Wang
- Institute of Medicinal Biotechnology, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, China
| | - Guoning Zhang
- Institute of Medicinal Biotechnology, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, China
| | - Yanpeng Zheng
- College of Life Sciences and Bioengineering, Beijing Jiaotong University, Beijing, China
| | - Jinsheng He
- College of Life Sciences and Bioengineering, Beijing Jiaotong University, Beijing, China
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Donovan-Banfield I, Milligan R, Hall S, Gao T, Murphy E, Li J, Shawli GT, Hiscox J, Zhuang X, McKeating JA, Fearns R, Matthews DA. Direct RNA sequencing of respiratory syncytial virus infected human cells generates a detailed overview of RSV polycistronic mRNA and transcript abundance. PLoS One 2022; 17:e0276697. [PMID: 36355791 PMCID: PMC9648745 DOI: 10.1371/journal.pone.0276697] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2022] [Accepted: 10/11/2022] [Indexed: 11/12/2022] Open
Abstract
To characterize species of viral mRNA transcripts generated during respiratory syncytial virus (RSV) infection, human fibroblast-like MRC-5 lung cells were infected with subgroup A RSV for 6, 16 and 24 hours. In addition, we characterised the viral transcriptome in infected Calu-3 lung epithelial cells at 48 hours post infection. Total RNA was harvested and polyadenylated mRNA was enriched and sequenced by direct RNA sequencing using an Oxford nanopore device. This platform yielded over 450,000 direct mRNA transcript reads which were mapped to the viral genome and analysed to determine the relative mRNA levels of viral genes using our in-house ORF-centric pipeline. We examined the frequency of polycistronic readthrough mRNAs were generated and assessed the length of the polyadenylated tails for each group of transcripts. We show a general but non-linear decline in gene transcript abundance across the viral genome, as predicted by the model of RSV gene transcription. However, the decline in transcript abundance is not uniform. The polyadenylate tails generated by the viral polymerase are similar in length to those generated by the host polyadenylation machinery and broadly declined in length for most transcripts as the infection progressed. Finally, we observed that the steady state abundance of transcripts with very short polyadenylate tails less than 20 nucleotides is less for N, SH and G transcripts in both cell lines compared to NS1, NS2, P, M, F and M2 which may reflect differences in mRNA stability and/or translation rates within and between the cell lines.
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Affiliation(s)
- I’ah Donovan-Banfield
- School of Cellular and Molecular Medicine, Faculty of Life Sciences, University of Bristol, Bristol, United Kingdom
- Department of Infection Biology and Microbiome, Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, United Kingdom
| | - Rachel Milligan
- School of Cellular and Molecular Medicine, Faculty of Life Sciences, University of Bristol, Bristol, United Kingdom
| | - Sophie Hall
- School of Cellular and Molecular Medicine, Faculty of Life Sciences, University of Bristol, Bristol, United Kingdom
| | - Tianyi Gao
- School of Cellular and Molecular Medicine, Faculty of Life Sciences, University of Bristol, Bristol, United Kingdom
| | - Eleanor Murphy
- School of Cellular and Molecular Medicine, Faculty of Life Sciences, University of Bristol, Bristol, United Kingdom
| | - Jack Li
- School of Cellular and Molecular Medicine, Faculty of Life Sciences, University of Bristol, Bristol, United Kingdom
| | - Ghada T. Shawli
- Department of Infection Biology and Microbiome, Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, United Kingdom
| | - Julian Hiscox
- Department of Infection Biology and Microbiome, Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, United Kingdom
| | - Xiaodong Zhuang
- Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Jane A. McKeating
- Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
- Chinese Academy of Medical Sciences Oxford Institute, University of Oxford, Oxford, United Kingdom
| | - Rachel Fearns
- Department of Microbiology, National Emerging Infectious Diseases Laboratories, Boston University School of Medicine, Boston, Massachusetts, United States of America
- * E-mail: (DAM); (RF)
| | - David A. Matthews
- School of Cellular and Molecular Medicine, Faculty of Life Sciences, University of Bristol, Bristol, United Kingdom
- * E-mail: (DAM); (RF)
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13
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Soto JA, Galvez NMS, Rivera DB, Díaz FE, Riedel CA, Bueno SM, Kalergis AM. From animal studies into clinical trials: the relevance of animal models to develop vaccines and therapies to reduce disease severity and prevent hRSV infection. Expert Opin Drug Discov 2022; 17:1237-1259. [PMID: 36093605 DOI: 10.1080/17460441.2022.2123468] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
INTRODUCTION Human respiratory syncytial virus (hRSV) is an important cause of lower respiratory tract infections in the pediatric and the geriatric population worldwide. There is a substantial economic burden resulting from hRSV disease during winter. Although no vaccines have been approved for human use, prophylactic therapies are available for high-risk populations. Choosing the proper animal models to evaluate different vaccine prototypes or pharmacological treatments is essential for developing efficient therapies against hRSV. AREAS COVERED This article describes the relevance of using different animal models to evaluate the effect of antiviral drugs, pharmacological molecules, vaccine prototypes, and antibodies in the protection against hRSV. The animal models covered are rodents, mustelids, bovines, and nonhuman primates. Animals included were chosen based on the available literature and their role in the development of the drugs discussed in this manuscript. EXPERT OPINION Choosing the correct animal model is critical for exploring and testing treatments that could decrease the impact of hRSV in high-risk populations. Mice will continue to be the most used preclinical model to evaluate this. However, researchers must also explore the use of other models such as nonhuman primates, as they are more similar to humans, prior to escalating into clinical trials.
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Affiliation(s)
- J A Soto
- Millennium Institute on Immunology and Immunotherapy, Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile.,Millennium Institute on Immunology and Immunotherapy, Departamento de Ciencias Biológicas, Facultad de Ciencias de la Vida, Universidad Andrés Bello, Santiago, Chile
| | - N M S Galvez
- Millennium Institute on Immunology and Immunotherapy, Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - D B Rivera
- Millennium Institute on Immunology and Immunotherapy, Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - F E Díaz
- Millennium Institute on Immunology and Immunotherapy, Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - C A Riedel
- Millennium Institute on Immunology and Immunotherapy, Departamento de Ciencias Biológicas, Facultad de Ciencias de la Vida, Universidad Andrés Bello, Santiago, Chile
| | - S M Bueno
- Millennium Institute on Immunology and Immunotherapy, Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - A M Kalergis
- Millennium Institute on Immunology and Immunotherapy, Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile.,Departamento de Endocrinología, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile
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14
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Sourimant J, Lieber CM, Yoon JJ, Toots M, Govindarajan M, Udumula V, Sakamoto K, Natchus MG, Patti J, Vernachio J, Plemper RK. Orally efficacious lead of the AVG inhibitor series targeting a dynamic interface in the respiratory syncytial virus polymerase. SCIENCE ADVANCES 2022; 8:eabo2236. [PMID: 35749502 PMCID: PMC9232112 DOI: 10.1126/sciadv.abo2236] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Accepted: 05/09/2022] [Indexed: 06/15/2023]
Abstract
Respiratory syncytial virus (RSV) is a leading cause of lower respiratory infections in infants and the immunocompromised, yet no efficient therapeutic exists. We have identified the AVG class of allosteric inhibitors of RSV RNA synthesis. Here, we demonstrate through biolayer interferometry and in vitro RNA-dependent RNA polymerase (RdRP) assays that AVG compounds bind to the viral polymerase, stalling the polymerase in initiation conformation. Resistance profiling revealed a unique escape pattern, suggesting a discrete docking pose. Affinity mapping using photoreactive AVG analogs identified the interface of polymerase core, capping, and connector domains as a molecular target site. A first-generation lead showed nanomolar potency against RSV in human airway epithelium organoids but lacked in vivo efficacy. Docking pose-informed synthetic optimization generated orally efficacious AVG-388, which showed potent efficacy in the RSV mouse model when administered therapeutically. This study maps a druggable target in the RSV RdRP and establishes clinical potential of the AVG chemotype against RSV disease.
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Affiliation(s)
- Julien Sourimant
- Center for Translational Antiviral Research, Institute for Biomedical Sciences, Georgia State University, Atlanta, GA 30303, USA
| | - Carolin M. Lieber
- Center for Translational Antiviral Research, Institute for Biomedical Sciences, Georgia State University, Atlanta, GA 30303, USA
| | - Jeong-Joong Yoon
- Center for Translational Antiviral Research, Institute for Biomedical Sciences, Georgia State University, Atlanta, GA 30303, USA
| | - Mart Toots
- Center for Translational Antiviral Research, Institute for Biomedical Sciences, Georgia State University, Atlanta, GA 30303, USA
| | | | - Venkata Udumula
- Emory Institute for Drug Development, Emory University, Atlanta, GA 30322, USA
| | - Kaori Sakamoto
- Department of Pathology, College of Veterinary Medicine, University of Georgia, Athens, GA 30602, USA
| | - Michael G. Natchus
- Emory Institute for Drug Development, Emory University, Atlanta, GA 30322, USA
| | - Joseph Patti
- Aviragen Therapeutics Inc, Alpharetta, GA 30009, USA
| | | | - Richard K. Plemper
- Center for Translational Antiviral Research, Institute for Biomedical Sciences, Georgia State University, Atlanta, GA 30303, USA
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15
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Discovery of a Novel Respiratory Syncytial Virus Replication Inhibitor. Antimicrob Agents Chemother 2021; 65:AAC.02576-20. [PMID: 33782012 PMCID: PMC8316115 DOI: 10.1128/aac.02576-20] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2020] [Accepted: 02/18/2021] [Indexed: 11/20/2022] Open
Abstract
A high-throughput screen of a Roche internal chemical library based on inhibition of the respiratory syncytial virus (RSV)-induced cytopathic effect (CPE) on HEp-2 cells was performed to identify RSV inhibitors. Over 2,000 hits were identified and confirmed to be efficacious against RSV infection in vitro Here, we report the discovery of a triazole-oxadiazole derivative, designated triazole-1, as an RSV replication inhibitor, and we characterize its mechanism of action. Triazole-1 inhibited the replication of both RSV A and B subtypes with 50% inhibitory concentration (IC50) values of approximately 1 μM, but it was not effective against other viruses, including influenza virus A, human enterovirus 71 (EV71), and vaccinia virus. Triazole-1 was shown to inhibit RSV replication when added at up to 8 h after viral entry, suggesting that it inhibits RSV after viral entry. In a minigenome reporter assay in which RSV transcription regulatory sequences flanking a luciferase gene were cotransfected with RSV N/P/L/M2-1 genes into HEp-2 cells, triazole-1 demonstrated specific and dose-dependent RSV transcription inhibitory effects. Consistent with these findings, deep sequencing of the genomes of triazole-1-resistant mutants revealed a single point mutation (A to G) at nucleotide 13546 of the RSV genome, leading to a T-to-A change at amino acid position 1684 of the L protein, which is the RSV RNA polymerase for both viral transcription and replication. The effect of triazole-1 on minigenome transcription, which was mediated by the L protein containing the T1684A mutation, was significantly reduced, suggesting that the T1684A mutation alone conferred viral resistance to triazole-1.
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16
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Cox RM, Sourimant J, Govindarajan M, Natchus MG, Plemper RK. Therapeutic targeting of measles virus polymerase with ERDRP-0519 suppresses all RNA synthesis activity. PLoS Pathog 2021; 17:e1009371. [PMID: 33621266 PMCID: PMC7935272 DOI: 10.1371/journal.ppat.1009371] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2020] [Revised: 03/05/2021] [Accepted: 02/10/2021] [Indexed: 12/20/2022] Open
Abstract
Morbilliviruses, such as measles virus (MeV) and canine distemper virus (CDV), are highly infectious members of the paramyxovirus family. MeV is responsible for major morbidity and mortality in non-vaccinated populations. ERDRP-0519, a pan-morbillivirus small molecule inhibitor for the treatment of measles, targets the morbillivirus RNA-dependent RNA-polymerase (RdRP) complex and displayed unparalleled oral efficacy against lethal infection of ferrets with CDV, an established surrogate model for human measles. Resistance profiling identified the L subunit of the RdRP, which harbors all enzymatic activity of the polymerase complex, as the molecular target of inhibition. Here, we examined binding characteristics, physical docking site, and the molecular mechanism of action of ERDRP-0519 through label-free biolayer interferometry, photoaffinity cross-linking, and in vitro RdRP assays using purified MeV RdRP complexes and synthetic templates. Results demonstrate that unlike all other mononegavirus small molecule inhibitors identified to date, ERDRP-0519 inhibits all phosphodiester bond formation in both de novo initiation of RNA synthesis at the promoter and RNA elongation by a committed polymerase complex. Photocrosslinking and resistance profiling-informed ligand docking revealed that this unprecedented mechanism of action of ERDRP-0519 is due to simultaneous engagement of the L protein polyribonucleotidyl transferase (PRNTase)-like domain and the flexible intrusion loop by the compound, pharmacologically locking the polymerase in pre-initiation conformation. This study informs selection of ERDRP-0519 as clinical candidate for measles therapy and identifies a previously unrecognized druggable site in mononegavirus L polymerase proteins that can silence all synthesis of viral RNA. The mononegavirus order contains major established and recently emerged human pathogens. Despite the threat to human health, antiviral therapeutics directed against this order remain understudied. The mononegavirus polymerase complex represents a promising drug target due to its central importance for both virus replication and viral mitigation of the innate host antiviral response. In this study, we have mechanistically characterized a clinical candidate small-molecule MeV polymerase inhibitor. The compound blocked all phosphodiester bond formation activity, a unique mechanism of action unlike all other known mononegavirus polymerase inhibitors. Photocrosslinking-based target site mapping demonstrated that this class-defining prototype inhibitor stabilizes a pre-initiation conformation of the viral polymerase complex that sterically cannot accommodate template RNA. Function-equivalent druggable sites exist in all mononegavirus polymerases. In addition to its direct anti-MeV impact, the insight gained in this study can therefore serve as a blueprint for indication spectrum expansion through structure-informed scaffold engineering or targeted drug discovery.
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Affiliation(s)
- Robert M. Cox
- Institute for Biomedical Sciences, Georgia State University, Atlanta, Georgia, United States of America
| | - Julien Sourimant
- Institute for Biomedical Sciences, Georgia State University, Atlanta, Georgia, United States of America
| | - Mugunthan Govindarajan
- Emory Institute for Drug Development, Emory University, Atlanta, Georgia, United States of America
| | - Michael G. Natchus
- Emory Institute for Drug Development, Emory University, Atlanta, Georgia, United States of America
| | - Richard K. Plemper
- Institute for Biomedical Sciences, Georgia State University, Atlanta, Georgia, United States of America
- * E-mail:
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17
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Dinesh DC, Tamilarasan S, Rajaram K, Bouřa E. Antiviral Drug Targets of Single-Stranded RNA Viruses Causing Chronic Human Diseases. Curr Drug Targets 2021; 21:105-124. [PMID: 31538891 DOI: 10.2174/1389450119666190920153247] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Revised: 08/08/2019] [Accepted: 08/08/2019] [Indexed: 02/08/2023]
Abstract
Ribonucleic acid (RNA) viruses associated with chronic diseases in humans are major threats to public health causing high mortality globally. The high mutation rate of RNA viruses helps them to escape the immune response and also is responsible for the development of drug resistance. Chronic infections caused by human immunodeficiency virus (HIV) and hepatitis viruses (HBV and HCV) lead to acquired immunodeficiency syndrome (AIDS) and hepatocellular carcinoma respectively, which are one of the major causes of human deaths. Effective preventative measures to limit chronic and re-emerging viral infections are absolutely necessary. Each class of antiviral agents targets a specific stage in the viral life cycle and inhibits them from its development and proliferation. Most often, antiviral drugs target a specific viral protein, therefore only a few broad-spectrum drugs are available. This review will be focused on the selected viral target proteins of pathogenic viruses containing single-stranded (ss) RNA genome that causes chronic infections in humans (e.g. HIV, HCV, Flaviviruses). In the recent past, an exponential increase in the number of available three-dimensional protein structures (>150000 in Protein Data Bank), allowed us to better understand the molecular mechanism of action of protein targets and antivirals. Advancements in the in silico approaches paved the way to design and develop several novels, highly specific small-molecule inhibitors targeting the viral proteins.
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Affiliation(s)
| | - Selvaraj Tamilarasan
- Section of Microbial Biotechnology, Charles Tanford Protein Center, Martin Luther University Halle-Wittenberg, Halle (Saale), Germany
| | - Kaushik Rajaram
- Department of Microbiology, Central University of Tamil Nadu, Thiruvarur, India
| | - Evžen Bouřa
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Prague, Czech Republic
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18
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In Vitro Primer-Based RNA Elongation and Promoter Fine Mapping of the Respiratory Syncytial Virus. J Virol 2020; 95:JVI.01897-20. [PMID: 33028717 PMCID: PMC7737744 DOI: 10.1128/jvi.01897-20] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Accepted: 09/29/2020] [Indexed: 11/20/2022] Open
Abstract
Respiratory syncytial virus (RSV) is a nonsegmented negative-sense (NNS) RNA virus and shares a similar RNA synthesis strategy with other members of NNS RNA viruses, such as measles, rabies virus, and Ebola virus. RSV RNA synthesis is catalyzed by a multifunctional RNA-dependent RNA polymerase (RdRP), which is composed of a large (L) protein that catalyzes three distinct enzymatic functions and an essential coenzyme phosphoprotein (P). Here, we successfully prepared highly pure, full-length, wild-type and mutant RSV polymerase (L-P) complexes. We demonstrated that the RSV polymerase could carry out both de novo and primer-based RNA synthesis. We defined the minimal length of the RNA template for in vitro de novo RNA synthesis using the purified RSV polymerase as 8 nucleotides (nt), shorter than previously reported. We showed that the RSV polymerase catalyzed primer-dependent RNA elongation with different lengths of primers on both short (10-nt) and long (25-nt) RNA templates. We compared the sequence specificity of different viral promoters and identified positions 3, 5, and 8 of the promoter sequence as essential to the in vitro RSV polymerase activity, consistent with the results previously mapped with the in vivo minigenome assay. Overall, these findings agree well with those of previous biochemical studies and extend our understanding of the promoter sequence and the mechanism of RSV RNA synthesis.IMPORTANCE As a major human pathogen, RSV affects 3.4 million children worldwide annually. However, no effective antivirals or vaccines are available. An in-depth mechanistic understanding of the RSV RNA synthesis machinery remains a high priority among the NNS RNA viruses. There is a strong public health need for research on this virus, due to major fundamental gaps in our understanding of NNS RNA virus replication. As the key enzyme executing transcription and replication of the virus, the RSV RdRP is a logical target for novel antiviral drugs. Therefore, exploring the primer-dependent RNA elongation extends our mechanistic understanding of the RSV RNA synthesis. Further fine mapping of the promoter sequence paves the way to better understand the function and structure of the RSV polymerase.
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19
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Elawar F, Oraby AK, Kieser Q, Jensen LD, Culp T, West FG, Marchant DJ. Pharmacological targets and emerging treatments for respiratory syncytial virus bronchiolitis. Pharmacol Ther 2020; 220:107712. [PMID: 33121940 DOI: 10.1016/j.pharmthera.2020.107712] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Accepted: 10/21/2020] [Indexed: 12/20/2022]
Abstract
RSV infection of the lower respiratory tract in infants is the leading cause of pediatric hospitalizations and second to malaria in causing infant deaths worldwide. RSV also causes substantial morbidity in immunocompromised and elderly populations. The only available therapeutic is a prophylactic drug called Palivizumab that is a humanized monoclonal antibody, given to high-risk infants. However, this intervention is expensive and has a limited impact on annual hospitalization rates caused by RSV. No vaccine is available, nor are efficacious antivirals to treat an active infection, and there is still no consensus on how infants with bronchiolitis should be treated during hospital admission. In this comprehensive review, we briefly outline the function of the RSV proteins and their suitability as therapeutic targets. We then discuss the most promising drug candidates, their inhibitory mechanisms, and whether they are in the process of clinical trials. We also briefly discuss the reasons for some of the failures in RSV therapeutics and vaccines. In summary, we provide insight into current antiviral development and the considerations toward producing licensed antivirals and therapeutics.
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Affiliation(s)
- Farah Elawar
- Li Ka Shing Institute of Virology, Department of Medical Microbiology and Immunology, University of Alberta, Edmonton, AB T6G 2R3, Canada
| | - Ahmed K Oraby
- Department of Chemistry, University of Alberta, Edmonton, Alberta T6G 2G2, Canada; Department of Pharmaceutical Organic Chemistry, Faculty of Pharmacy, Misr University for Science &Technology, Al-Motamayez District, 6th of October City, P.O. Box 77, Egypt
| | - Quinten Kieser
- Li Ka Shing Institute of Virology, Department of Medical Microbiology and Immunology, University of Alberta, Edmonton, AB T6G 2R3, Canada
| | - Lionel D Jensen
- Li Ka Shing Institute of Virology, Department of Medical Microbiology and Immunology, University of Alberta, Edmonton, AB T6G 2R3, Canada
| | - Tyce Culp
- Li Ka Shing Institute of Virology, Department of Medical Microbiology and Immunology, University of Alberta, Edmonton, AB T6G 2R3, Canada
| | - Frederick G West
- Department of Chemistry, University of Alberta, Edmonton, Alberta T6G 2G2, Canada
| | - David J Marchant
- Li Ka Shing Institute of Virology, Department of Medical Microbiology and Immunology, University of Alberta, Edmonton, AB T6G 2R3, Canada.
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20
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Hannemann H. Viral replicons as valuable tools for drug discovery. Drug Discov Today 2020; 25:1026-1033. [PMID: 32272194 PMCID: PMC7136885 DOI: 10.1016/j.drudis.2020.03.010] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Revised: 02/28/2020] [Accepted: 03/13/2020] [Indexed: 12/15/2022]
Abstract
RNA viruses can cause severe diseases such as dengue, Lassa, chikungunya and Ebola. Many of these viruses can only be propagated under high containment levels, necessitating the development of low containment surrogate systems such as subgenomic replicons and minigenome systems. Replicons are self-amplifying recombinant RNA molecules expressing proteins sufficient for their own replication but which do not produce infectious virions. Replicons can persist in cells and are passed on during cell division, enabling quick, efficient and high-throughput testing of drug candidates that act on viral transcription, translation and replication. This review will explore the history and potential for drug discovery of hepatitis C virus, dengue virus, respiratory syncytial virus, Ebola virus and norovirus replicon and minigenome systems.
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Affiliation(s)
- Holger Hannemann
- The Native Antigen Company, Langford Locks, Kidlington OX5 1LH, UK.
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21
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Aggarwal M, Plemper RK. Structural Insight into Paramyxovirus and Pneumovirus Entry Inhibition. Viruses 2020; 12:E342. [PMID: 32245118 PMCID: PMC7150754 DOI: 10.3390/v12030342] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2020] [Revised: 03/17/2020] [Accepted: 03/18/2020] [Indexed: 01/04/2023] Open
Abstract
Paramyxoviruses and pneumoviruses infect cells through fusion (F) protein-mediated merger of the viral envelope with target membranes. Members of these families include a range of major human and animal pathogens, such as respiratory syncytial virus (RSV), measles virus (MeV), human parainfluenza viruses (HPIVs), and highly pathogenic Nipah virus (NiV). High-resolution F protein structures in both the metastable pre- and the postfusion conformation have been solved for several members of the families and a number of F-targeting entry inhibitors have progressed to advanced development or clinical testing. However, small-molecule RSV entry inhibitors have overall disappointed in clinical trials and viral resistance developed rapidly in experimental settings and patients, raising the question of whether the available structural information may provide a path to counteract viral escape through proactive inhibitor engineering. This article will summarize current mechanistic insight into F-mediated membrane fusion and examine the contribution of structural information to the development of small-molecule F inhibitors. Implications are outlined for future drug target selection and rational drug engineering strategies.
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Affiliation(s)
| | - Richard K Plemper
- Institute for Biomedical Sciences, Georgia State University, Atlanta, GA 30303, USA;
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22
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Bergeron HC, Tripp RA. Emerging small and large molecule therapeutics for respiratory syncytial virus. Expert Opin Investig Drugs 2020; 29:285-294. [PMID: 32096420 DOI: 10.1080/13543784.2020.1735349] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Introduction: Respiratory syncytial virus (RSV) causes lower respiratory tract infections and can lead to morbidity and mortality in the infant, elderly and immunocompromised. There is no vaccine and therapeutic interventions are limited. RSV disease research has yielded the development of several prophylactic and therapeutic treatments. Several promising candidates are currently under investigation.Areas covered: Small and large molecule approaches to RSV treatment were examined and categorized by their mechanism of action using data from PubMed, clinicaltrials.gov, and from the sponsoring organizations publicly available pipeline information. These results are prefaced by an overview of RSV to provide the context for rational therapy development.Expert opinion: While small molecule drugs show promise for RSV treatment, we believe that large molecule therapy using anti-RSV G and F protein monoclonal antibodies (mAbs) will most efficaciously and safely ameliorate RSV disease.
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Affiliation(s)
- Harrison C Bergeron
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, GA, USA
| | - Ralph A Tripp
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, GA, USA
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Mirabelli C, Jaspers M, Boon M, Jorissen M, Koukni M, Bardiot D, Chaltin P, Marchand A, Neyts J, Jochmans D. Differential antiviral activities of respiratory syncytial virus (RSV) inhibitors in human airway epithelium. J Antimicrob Chemother 2019; 73:1823-1829. [PMID: 29596680 PMCID: PMC6005027 DOI: 10.1093/jac/dky089] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2017] [Accepted: 02/22/2018] [Indexed: 12/11/2022] Open
Abstract
Objectives We report the use of reconstituted 3D human airway epithelium cells (HuAECs) of bronchial origin in an air–liquid interface to study respiratory syncytial virus (RSV) infection and to assess the efficacy of RSV inhibitors in (pre-)clinical development. Methods HuAECs were infected with RSV-A Long strain (0.01 CCID50/cell, where CCID50 represents 50% cell culture infectious dose in HEp2 cells) on the apical compartment of the culture. At the time of infection or at 1 or 3 days post-infection, selected inhibitors were added and refreshed daily on the basal compartment of the culture. Viral shedding was followed up by apical washes collected daily and quantifying viral RNA by RT-qPCR. Results RSV-A replicates efficiently in HuAECs and viral RNA is shed for weeks after infection. RSV infection reduces the ciliary beat frequency of the ciliated cells as of 4 days post-infection, with complete ciliary dyskinesia observed by day 10. Treatment with RSV fusion inhibitors resulted in an antiviral effect only when added at the time of infection. In contrast, the use of replication inhibitors (both nucleoside and non-nucleoside) elicited a marked antiviral effect even when the start of treatment was delayed until 1 day or even 3 days after infection. Levels of the inflammation marker RANTES (mRNA) increased ∼200-fold in infected, untreated cultures (at 3 weeks post-infection), but levels were comparable to those of uninfected cultures in the presence of PC786, an RSV replication inhibitor, suggesting that an efficient antiviral treatment might inhibit virus-induced inflammation in this model. Conclusions Overall, HuAECs offer a robust and physiologically relevant model to study RSV replication and to assess the efficacy of antiviral compounds.
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Affiliation(s)
- Carmen Mirabelli
- Laboratory of Virology and Chemotherapy, Department of Microbiology and Immunology, Rega Institute for Medical Research, KU Leuven, B-3000 Leuven, Belgium
| | - Martine Jaspers
- Research Group Oto-Rhino-Laryngology, KU Leuven and Leuven University Hospitals, B-3000 Leuven, Belgium
| | - Mieke Boon
- Department of Pediatrics, Pediatric Pulmonology, University Hospital Leuven, B-3000 Leuven, Belgium.,Department of Development and Regeneration, Organ Systems, KU Leuven, B-3000 Leuven, Belgium
| | - Mark Jorissen
- Research Group Oto-Rhino-Laryngology, KU Leuven and Leuven University Hospitals, B-3000 Leuven, Belgium
| | - Mohamed Koukni
- Cistim Leuven vzw, Bioincubator 2, Gaston Geenslaan 2, 3001 Leuven, Belgium
| | - Dorothée Bardiot
- Cistim Leuven vzw, Bioincubator 2, Gaston Geenslaan 2, 3001 Leuven, Belgium
| | - Patrick Chaltin
- Cistim Leuven vzw, Bioincubator 2, Gaston Geenslaan 2, 3001 Leuven, Belgium.,Center for Drug Design and Development (CD3), KU Leuven R&D, Waaistraat 6, B-3000 Leuven, Belgium
| | - Arnaud Marchand
- Cistim Leuven vzw, Bioincubator 2, Gaston Geenslaan 2, 3001 Leuven, Belgium
| | - Johan Neyts
- Laboratory of Virology and Chemotherapy, Department of Microbiology and Immunology, Rega Institute for Medical Research, KU Leuven, B-3000 Leuven, Belgium
| | - Dirk Jochmans
- Laboratory of Virology and Chemotherapy, Department of Microbiology and Immunology, Rega Institute for Medical Research, KU Leuven, B-3000 Leuven, Belgium
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Fu YH, Xu ZX, Jiang N, Zheng YP, Rameix-Welti MA, Jiao YY, Peng XL, Wang Y, Eleouet JF, Cen S, He JS. High-throughput screening of active compounds against human respiratory syncytial virus. Virology 2019; 535:171-178. [DOI: 10.1016/j.virol.2019.07.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2019] [Revised: 06/02/2019] [Accepted: 07/01/2019] [Indexed: 12/29/2022]
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25
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Joshi S, Bawage S, Tiwari P, Kirby D, Perrie Y, Dennis V, Singh SR. Liposomes: a promising carrier for respiratory syncytial virus therapeutics. Expert Opin Drug Deliv 2019; 16:969-980. [DOI: 10.1080/17425247.2019.1652268] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Affiliation(s)
- Sameer Joshi
- Center for NanoBiotechnology Research, Alabama State University, Montgomery, AL, USA
| | - Swapnil Bawage
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA, USA
| | - Pooja Tiwari
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA, USA
| | - Daniel Kirby
- Aston Pharmacy School, School of Life and Health Sciences, Aston University, Birmingham, UK
| | - Yvonne Perrie
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, UK
| | - Vida Dennis
- Center for NanoBiotechnology Research, Alabama State University, Montgomery, AL, USA
| | - Shree R Singh
- Center for NanoBiotechnology Research, Alabama State University, Montgomery, AL, USA
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26
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Cressey TN, Noton SL, Nagendra K, Braun MR, Fearns R. Mechanism for de novo initiation at two sites in the respiratory syncytial virus promoter. Nucleic Acids Res 2019; 46:6785-6796. [PMID: 29873775 PMCID: PMC6061868 DOI: 10.1093/nar/gky480] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Accepted: 05/17/2018] [Indexed: 12/18/2022] Open
Abstract
The respiratory syncytial virus (RSV) RNA dependent RNA polymerase (RdRp) initiates two RNA synthesis processes from the viral promoter: genome replication from position 1U and mRNA transcription from position 3C. Here, we examined the mechanism by which a single promoter can direct initiation from two sites. We show that initiation at 1U and 3C occurred independently of each other, and that the same RdRp was capable of precisely selecting the two sites. The RdRp preferred to initiate at 3C, but initiation site selection could be modulated by the relative concentrations of ATP versus GTP. Analysis of template mutations indicated that the RdRp could bind ATP and CTP, or GTP, independently of template nucleotides. The data suggest a model in which innate affinity of the RdRp for particular NTPs, coupled with a repeating element within the promoter, allows precise initiation of replication at 1U or transcription at 3C.
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Affiliation(s)
- Tessa N Cressey
- Department of Microbiology, Boston University School of Medicine, Boston, MA 02118, USA
| | - Sarah L Noton
- Department of Microbiology, Boston University School of Medicine, Boston, MA 02118, USA
| | - Kartikeya Nagendra
- Department of Microbiology, Boston University School of Medicine, Boston, MA 02118, USA
| | - Molly R Braun
- Department of Microbiology, Boston University School of Medicine, Boston, MA 02118, USA
| | - Rachel Fearns
- Department of Microbiology, Boston University School of Medicine, Boston, MA 02118, USA
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27
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Norris MJ, Malhi M, Duan W, Ouyang H, Granados A, Cen Y, Tseng YC, Gubbay J, Maynes J, Moraes TJ. Targeting Intracellular Ion Homeostasis for the Control of Respiratory Syncytial Virus. Am J Respir Cell Mol Biol 2019; 59:733-744. [PMID: 30095982 DOI: 10.1165/rcmb.2017-0345oc] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Respiratory syncytial virus (RSV) is a leading cause of mortality in infants and young children. Despite the RSV disease burden, no vaccine is available, and treatment remains nonspecific. New drug candidates are needed to combat RSV. Toward this goal, we screened over 2,000 compounds to identify approved drugs with novel anti-RSV activity. Cardiac glycosides, inhibitors of the membrane-bound Na+/K+-ATPase, were identified to have anti-RSV activity. Cardiac glycosides diminished RSV infection in human epithelial type 2 cells and in primary human airway epithelial cells grown at an air-liquid interface. Digoxin, a U.S. Food and Drug Administration-approved cardiac glycoside, was also able to inhibit infection of primary nasal epithelial cells with community isolates of RSV. Our results suggest that the antiviral effects of cardiac glycosides may be dependent on changes in the intracellular Na+ and K+ composition. Consistent with this mechanism, we demonstrated that the ionophoric antibiotics salinomycin, valinomycin, and monensin inhibited RSV in human epithelial type 2 cells and primary nasal epithelial cells. Our data indicate that the K+/Na+-sensitive steps in the RSV life cycle occur within the initial 4 hours of viral infection but do not include virus binding/entry. Rather, our findings demonstrated a negative effect on the RSV transcription and/or replication process. Overall, this work suggests that targeting intracellular ion concentrations offers a novel antiviral strategy.
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Affiliation(s)
- Michael J Norris
- 1 Department of Laboratory Medicine and Pathobiology and.,2 Program in Translational Medicine
| | - Manpreet Malhi
- 3 Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada.,4 Program in Molecular Medicine
| | | | | | - Andrea Granados
- 1 Department of Laboratory Medicine and Pathobiology and.,5 Public Health Ontario, Toronto, Ontario, Canada
| | | | | | | | - Jason Maynes
- 4 Program in Molecular Medicine.,6 Department of Anesthesia and Pain Medicine, and
| | - Theo J Moraes
- 1 Department of Laboratory Medicine and Pathobiology and.,2 Program in Translational Medicine.,7 Division of Respiratory Medicine, Department of Pediatrics, Hospital for Sick Children, Toronto, Ontario, Canada; and
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28
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Noton SL, Tremaglio CZ, Fearns R. Killing two birds with one stone: How the respiratory syncytial virus polymerase initiates transcription and replication. PLoS Pathog 2019; 15:e1007548. [PMID: 30817806 PMCID: PMC6394897 DOI: 10.1371/journal.ppat.1007548] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Affiliation(s)
- Sarah L. Noton
- Department of Microbiology, Boston University School of Medicine, Boston, Massachusetts, United States of America
| | - Chadene Z. Tremaglio
- Department of Biology, University of Saint Joseph, West Hartford, Connecticut, United States of America
| | - Rachel Fearns
- Department of Microbiology, Boston University School of Medicine, Boston, Massachusetts, United States of America
- * E-mail:
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29
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Cockerill GS, Good JAD, Mathews N. State of the Art in Respiratory Syncytial Virus Drug Discovery and Development. J Med Chem 2018; 62:3206-3227. [DOI: 10.1021/acs.jmedchem.8b01361] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- G. Stuart Cockerill
- ReViral Ltd., Stevenage Bioscience Catalyst, Gunnels Wood Road, Stevenage, Hertfordshire SG1 2FX, United Kingdom
| | - James A. D. Good
- ReViral Ltd., Stevenage Bioscience Catalyst, Gunnels Wood Road, Stevenage, Hertfordshire SG1 2FX, United Kingdom
| | - Neil Mathews
- ReViral Ltd., Stevenage Bioscience Catalyst, Gunnels Wood Road, Stevenage, Hertfordshire SG1 2FX, United Kingdom
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30
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Cox RM, Toots M, Yoon JJ, Sourimant J, Ludeke B, Fearns R, Bourque E, Patti J, Lee E, Vernachio J, Plemper RK. Development of an allosteric inhibitor class blocking RNA elongation by the respiratory syncytial virus polymerase complex. J Biol Chem 2018; 293:16761-16777. [PMID: 30206124 DOI: 10.1074/jbc.ra118.004862] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2018] [Revised: 09/10/2018] [Indexed: 12/22/2022] Open
Abstract
Respiratory syncytial virus (RSV) represents a significant health threat to infants and to elderly or immunocompromised individuals. There are currently no vaccines available to prevent RSV infections, and disease management is largely limited to supportive care, making the identification and development of effective antiviral therapeutics against RSV a priority. To identify effective chemical scaffolds for managing RSV disease, we conducted a high-throughput anti-RSV screen of a 57,000-compound library. We identified a hit compound that specifically blocked activity of the RSV RNA-dependent RNA polymerase (RdRp) complex, initially with moderate low-micromolar potency. Mechanistic characterization in an in vitro RSV RdRp assay indicated that representatives of this compound class block elongation of RSV RNA products after initial extension by up to three nucleotides. Synthetic hit-to-lead exploration yielded an informative 3D quantitative structure-activity relationship (3D-QSAR) model and resulted in analogs with more than 20-fold improved potency and selectivity indices (SIs) of >1,000. However, first-generation leads exhibited limited water solubility and poor metabolic stability. A second optimization strategy informed by the 3D-QSAR model combined with in silico pharmacokinetics (PK) predictions yielded an advanced lead, AVG-233, that demonstrated nanomolar activity against both laboratory-adapted RSV strains and clinical RSV isolates. This anti-RSV activity extended to infection of established cell lines and primary human airway cells. PK profiling in mice revealed 34% oral bioavailability of AVG-233 and sustained high drug levels in the circulation after a single oral dose of 20 mg/kg. This promising first-in-class lead warrants further development as an anti-RSV drug.
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Affiliation(s)
- Robert M Cox
- From the Institute for Biomedical Sciences, Georgia State University, Atlanta, Georgia 30303
| | - Mart Toots
- From the Institute for Biomedical Sciences, Georgia State University, Atlanta, Georgia 30303
| | - Jeong-Joong Yoon
- From the Institute for Biomedical Sciences, Georgia State University, Atlanta, Georgia 30303
| | - Julien Sourimant
- From the Institute for Biomedical Sciences, Georgia State University, Atlanta, Georgia 30303
| | - Barbara Ludeke
- the Department of Microbiology, Boston University School of Medicine, Boston, Massachusetts 02118, and
| | - Rachel Fearns
- the Department of Microbiology, Boston University School of Medicine, Boston, Massachusetts 02118, and
| | | | - Joseph Patti
- Aviragen Therapeutics, Alpharetta, Georgia 30009
| | - Edward Lee
- Aviragen Therapeutics, Alpharetta, Georgia 30009
| | | | - Richard K Plemper
- From the Institute for Biomedical Sciences, Georgia State University, Atlanta, Georgia 30303,
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31
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Atienza BJP, Jensen LD, Noton SL, Ansalem AKV, Hobman T, Fearns R, Marchant DJ, West FG. Dual Catalytic Synthesis of Antiviral Compounds Based on Metallocarbene-Azide Cascade Chemistry. J Org Chem 2018; 83:6829-6842. [PMID: 29663810 DOI: 10.1021/acs.joc.8b00222] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Aryl azides trap ortho-metallocarbene intermediates to generate indolenones possessing a reactive C-acylimine moiety, which can react with added indole nucleophiles to afford the 2-(3-indolyl)indolin-3-one scaffold found in the antiviral natural product isatisine A. This overall process occurs through a dual catalytic sequence at room temperature. Redox activation of the Cu(OTf)2 precatalyst by indole results in catalytically competent Cu(I) required for azide-metallocarbene coupling. The Brønsted acid that is also formed from Cu(OTf)2 reduction is responsible for catalysis of the C-C bond-forming indole addition step. This modular, procedurally simple method allows for rapid assembly of bis(indole) libraries, several of which proved to have anti-infective activity against respiratory syncytial virus and Zika virus.
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Affiliation(s)
- Bren Jordan P Atienza
- Department of Chemistry , University of Alberta , Edmonton , Alberta T6G 2G2 , Canada
| | - Lionel D Jensen
- Department of Medical Microbiology and Immunology, Faculty of Medicine and Dentistry , University of Alberta , Edmonton , Alberta T6G 2E1 , Canada
| | - Sarah L Noton
- Department of Microbiology , Boston University School of Medicine , Boston , Massachusetts 02118 , United States
| | - Anil Kumar Victoria Ansalem
- Department of Medical Microbiology and Immunology, Faculty of Medicine and Dentistry , University of Alberta , Edmonton , Alberta T6G 2E1 , Canada
| | - Tom Hobman
- Department of Medical Microbiology and Immunology, Faculty of Medicine and Dentistry , University of Alberta , Edmonton , Alberta T6G 2E1 , Canada
| | - Rachel Fearns
- Department of Microbiology , Boston University School of Medicine , Boston , Massachusetts 02118 , United States
| | - David J Marchant
- Department of Medical Microbiology and Immunology, Faculty of Medicine and Dentistry , University of Alberta , Edmonton , Alberta T6G 2E1 , Canada
| | - F G West
- Department of Chemistry , University of Alberta , Edmonton , Alberta T6G 2G2 , Canada
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32
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Brookes DW, Coates M, Allen H, Daly L, Constant S, Huang S, Hows M, Davis A, Cass L, Ayrton J, Knowles I, Strong P, Rapeport G, Ito K. Late therapeutic intervention with a respiratory syncytial virus L-protein polymerase inhibitor, PC786, on respiratory syncytial virus infection in human airway epithelium. Br J Pharmacol 2018; 175:2520-2534. [PMID: 29579332 PMCID: PMC5980447 DOI: 10.1111/bph.14221] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2017] [Revised: 03/12/2018] [Accepted: 03/14/2018] [Indexed: 01/03/2023] Open
Abstract
BACKGROUND AND PURPOSE Effective anti-respiratory syncytial virus (RSV) agents are still not available for clinical use. Current major targets are virus surface proteins, such as a fusion protein involved in viral entry, but agents effective after RSV infection is established are required. Here we have investigated the effects of late therapeutic intervention with a novel inhaled RSV polymerase inhibitor, PC786, on RSV infection in human airway epithelium. EXPERIMENTAL APPROACH Air liquid interface-cultured bronchial or small airway epithelium was infected with RSVA2. PC786 was applied apically or basolaterally once daily following peak virus load on Day 3 post inoculation. Apical wash was collected daily for determination of viral burden by PCR and plaque assay (primary endpoints) and biomarker analyses. The effects were compared with those of ALS-8112, an anti-RSV nucleoside analogue, and GS-5806, a fusion-protein inhibitor, which were treated basolaterally. KEY RESULTS Late intervention with GS-5806 did not show significant anti-viral effects, but PC786 produced potent, concentration-dependent inhibition of viral replication with viral load falling below detectable limits 3 days after treatment commenced in airway epithelium. These effects were superior to those of ALS-8112. PC786 showed inhibitory activities against RSV-induced increases of CCL5, IL-6, double-strand DNA and mucin. The effects of PC786 were also confirmed in small airway epithelium. CONCLUSION AND IMPLICATIONS Late therapeutic intervention with the RSV polymerase inhibitor, PC786, reduced the viral burden quickly in human airway epithelium. Thus, PC786 demonstrates the potential to be an effective therapeutic agent to treat active RSV infection.
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Pickens JA, Tripp RA. Verdinexor Targeting of CRM1 is a Promising Therapeutic Approach against RSV and Influenza Viruses. Viruses 2018; 10:E48. [PMID: 29361733 PMCID: PMC5795461 DOI: 10.3390/v10010048] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2017] [Revised: 01/15/2018] [Accepted: 01/17/2018] [Indexed: 12/11/2022] Open
Abstract
Two primary causes of respiratory tract infections are respiratory syncytial virus (RSV) and influenza viruses, both of which remain major public health concerns. There are a limited number of antiviral drugs available for the treatment of RSV and influenza, each having limited effectiveness and each driving selective pressure for the emergence of drug-resistant viruses. Novel broad-spectrum antivirals are needed to circumvent problems with current disease intervention strategies, while improving the cytokine-induced immunopathology associated with RSV and influenza infections. In this review, we examine the use of Verdinexor (KPT-335, a novel orally bioavailable drug that functions as a selective inhibitor of nuclear export, SINE), as an antiviral with multifaceted therapeutic potential. KPT-335 works to (1) block CRM1 (i.e., Chromosome Region Maintenance 1; exportin 1 or XPO1) mediated export of viral proteins critical for RSV and influenza pathogenesis; and (2) repress nuclear factor κB (NF-κB) activation, thus reducing cytokine production and eliminating virus-associated immunopathology. The repurposing of SINE compounds as antivirals shows promise not only against RSV and influenza virus but also against other viruses that exploit the nucleus as part of their viral life cycle.
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Affiliation(s)
- Jennifer A Pickens
- Department of Infectious Diseases, University of Georgia, Athens, GA 30602, USA.
| | - Ralph A Tripp
- Department of Infectious Diseases, University of Georgia, Athens, GA 30602, USA.
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34
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Braun MR, Deflubé LR, Noton SL, Mawhorter ME, Tremaglio CZ, Fearns R. RNA elongation by respiratory syncytial virus polymerase is calibrated by conserved region V. PLoS Pathog 2017; 13:e1006803. [PMID: 29281742 PMCID: PMC5760109 DOI: 10.1371/journal.ppat.1006803] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2017] [Revised: 01/09/2018] [Accepted: 12/11/2017] [Indexed: 02/06/2023] Open
Abstract
The large polymerase subunit (L) of non-segmented negative strand RNA viruses transcribes viral mRNAs and replicates the viral genome. Studies with VSV have shown that conserved region V (CRV) of the L protein is part of the capping domain. However, CRV folds over and protrudes into the polymerization domain, suggesting that it might also have a role in RNA synthesis. In this study, the role of respiratory syncytial virus (RSV) CRV was evaluated using single amino acid substitutions and a small molecule inhibitor called BI-D. Effects were analyzed using cell-based minigenome and in vitro biochemical assays. Several amino acid substitutions inhibited production of capped, full-length mRNA and instead resulted in accumulation of short transcripts of approximately 40 nucleotides in length, confirming that RSV CRV has a role in capping. In addition, all six variants tested were either partially or completely defective in RNA replication. This was due to an inability of the polymerase to efficiently elongate the RNA within the promoter region. BI-D also inhibited transcription and replication. In this case, polymerase elongation activity within the promoter region was enhanced, such that the small RNA transcribed from the promoter was not released and instead was elongated past the first gene start signal. This was accompanied by a decrease in mRNA initiation at the first gene start signal and accumulation of aberrant RNAs of varying length. Thus, in addition to its function in mRNA capping, conserved region V modulates the elongation properties of the polymerase to enable productive transcription and replication to occur.
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MESH Headings
- Amino Acid Sequence
- Amino Acid Substitution
- Antiviral Agents/pharmacology
- Cell Line
- Conserved Sequence
- Drug Discovery
- Genes, Viral
- Humans
- Models, Molecular
- Promoter Regions, Genetic
- RNA Caps/genetics
- RNA Caps/metabolism
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- RNA, Viral/genetics
- RNA, Viral/metabolism
- RNA-Dependent RNA Polymerase/chemistry
- RNA-Dependent RNA Polymerase/genetics
- RNA-Dependent RNA Polymerase/metabolism
- Respiratory Syncytial Virus Infections/drug therapy
- Respiratory Syncytial Virus Infections/virology
- Respiratory Syncytial Virus, Human/genetics
- Respiratory Syncytial Virus, Human/metabolism
- Respiratory Syncytial Virus, Human/pathogenicity
- Transcription Elongation, Genetic
- Viral Proteins/chemistry
- Viral Proteins/genetics
- Viral Proteins/metabolism
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Affiliation(s)
- Molly R. Braun
- Department of Microbiology, Boston University School of Medicine, Boston, MA, United States of America
| | - Laure R. Deflubé
- Department of Microbiology, Boston University School of Medicine, Boston, MA, United States of America
| | - Sarah L. Noton
- Department of Microbiology, Boston University School of Medicine, Boston, MA, United States of America
| | - Michael E. Mawhorter
- Department of Microbiology, Boston University School of Medicine, Boston, MA, United States of America
| | - Chadene Z. Tremaglio
- Department of Microbiology, Boston University School of Medicine, Boston, MA, United States of America
| | - Rachel Fearns
- Department of Microbiology, Boston University School of Medicine, Boston, MA, United States of America
- * E-mail:
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35
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Respiratory Syncytial Virus: Infection, Detection, and New Options for Prevention and Treatment. Clin Microbiol Rev 2017; 30:277-319. [PMID: 27903593 DOI: 10.1128/cmr.00010-16] [Citation(s) in RCA: 342] [Impact Index Per Article: 48.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Respiratory syncytial virus (RSV) infection is a significant cause of hospitalization of children in North America and one of the leading causes of death of infants less than 1 year of age worldwide, second only to malaria. Despite its global impact on human health, there are relatively few therapeutic options available to prevent or treat RSV infection. Paradoxically, there is a very large volume of information that is constantly being refined on RSV replication, the mechanisms of RSV-induced pathology, and community transmission. Compounding the burden of acute RSV infections is the exacerbation of preexisting chronic airway diseases and the chronic sequelae of RSV infection. A mechanistic link is even starting to emerge between asthma and those who suffer severe RSV infection early in childhood. In this article, we discuss developments in the understanding of RSV replication, pathogenesis, diagnostics, and therapeutics. We attempt to reconcile the large body of information on RSV and why after many clinical trials there is still no efficacious RSV vaccine and few therapeutics.
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Preclinical Characterization of PC786, an Inhaled Small-Molecule Respiratory Syncytial Virus L Protein Polymerase Inhibitor. Antimicrob Agents Chemother 2017; 61:AAC.00737-17. [PMID: 28652242 PMCID: PMC5571287 DOI: 10.1128/aac.00737-17] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2017] [Accepted: 06/15/2017] [Indexed: 12/14/2022] Open
Abstract
Although respiratory syncytial virus (RSV) is the most common cause of lower respiratory tract infection in infants and young children, attempts to develop an effective therapy have so far proved unsuccessful. Here we report the preclinical profiles of PC786, a potent nonnucleoside RSV L protein polymerase inhibitor, designed for inhalation treatment of RSV infection. PC786 demonstrated a potent and selective antiviral activity against laboratory-adapted or clinical isolates of RSV-A (50% inhibitory concentration [IC50], <0.09 to 0.71 nM) and RSV-B (IC50, 1.3 to 50.6 nM), which were determined by inhibition of cytopathic effects in HEp-2 cells without causing detectable cytotoxicity. The underlying inhibition of virus replication was confirmed by PCR analysis. The effects of PC786 were largely unaffected by the multiplicity of infection (MOI) and were retained in the face of established RSV replication in a time-of-addition study. Persistent anti-RSV effects of PC786 were also demonstrated in human bronchial epithelial cells. In vivo intranasal once daily dosing with PC786 was able to reduce the virus load to undetectable levels in lung homogenates from RSV-infected mice and cotton rats. Treatment with escalating concentrations identified a dominant mutation in the L protein (Y1631H) in vitro. In addition, PC786 potently inhibited RSV RNA-dependent RNA polymerase (RdRp) activity in a cell-free enzyme assay and minigenome assay in HEp-2 cells (IC50, 2.1 and 0.5 nM, respectively). Thus, PC786 was shown to be a potent anti-RSV agent via inhibition of RdRp activity, making topical treatment with this compound a novel potential therapy for the treatment of human RSV infections.
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37
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Jorquera PA, Tripp RA. Respiratory syncytial virus: prospects for new and emerging therapeutics. Expert Rev Respir Med 2017; 11:609-615. [PMID: 28574729 DOI: 10.1080/17476348.2017.1338567] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
INTRODUCTION Respiratory syncytial virus (RSV) is the major cause of lower respiratory tract infections (LRTI) in infants, the elderly, and the immunocompromised. Although the development of a RSV vaccine has been a priority for >50 years, there is still no vaccine available. Treatment of RSV LRTI has remained mostly supportive, i.e. hydration and oxygenation. Palivizumab and ribavirin are the only options currently available for prevention and treatment of RSV infection, but evidence suggests that they are not fully effective. This creates a significant unmet medical need for new therapeutics for prevention and treatment of RSV worldwide. Areas covered: This article reviews the antiviral drugs and monoclonal antibodies (mAb) for RSV that are in different stages of clinical development. Expert commentary: Over the last 10 years, new antiviral drugs and mAb have shown clinical promise against RSV, and may become available in the coming years. Although the RSV fusion protein has been the most popular target for inhibitors and mAbs, new approaches targeting other viral proteins have shown promising results. To overcome the emergence of RSV escape mutants, combination antiviral therapy may be explored in the future.
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Affiliation(s)
- Patricia A Jorquera
- a Department of Infectious Disease, College of Veterinary Medicine , University of Georgia , Athens , GA , USA
| | - Ralph A Tripp
- a Department of Infectious Disease, College of Veterinary Medicine , University of Georgia , Athens , GA , USA
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Discovery of novel benzothienoazepine derivatives as potent inhibitors of respiratory syncytial virus. Bioorg Med Chem Lett 2017; 27:2201-2206. [PMID: 28372911 DOI: 10.1016/j.bmcl.2017.03.053] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2017] [Revised: 03/15/2017] [Accepted: 03/20/2017] [Indexed: 11/22/2022]
Abstract
The development of novel non-nucleoside inhibitors of the RSV polymerase complex is of significant clinical interest. Compounds derived from the benzothienoazepine core, such as AZ-27, are potent inhibitors of RSV viruses of the A-subgroup, but are only moderately active against the B serotype and as yet have not demonstrated activity in vivo. Herein we report the discovery of several novel families of C-2 arylated benzothienoazepine derivatives that are highly potent RSV polymerase inhibitors and reveal an exemplary structure, compound 4a, which shows low nanomolar activity against both RSV A and B viral subtypes. Furthermore, this compound is effective at suppressing viral replication, when administered intranasally, in a rodent model of RSV infection. These results suggest that compounds belonging to this chemotypes have the potential to provide superior anti-RSV agents than those currently available for clinical use.
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Drug candidates and model systems in respiratory syncytial virus antiviral drug discovery. Biochem Pharmacol 2017; 127:1-12. [DOI: 10.1016/j.bcp.2016.09.014] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2016] [Accepted: 09/16/2016] [Indexed: 12/11/2022]
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Heat Shock Protein 70 Family Members Interact with Crimean-Congo Hemorrhagic Fever Virus and Hazara Virus Nucleocapsid Proteins and Perform a Functional Role in the Nairovirus Replication Cycle. J Virol 2016; 90:9305-16. [PMID: 27512070 PMCID: PMC5044845 DOI: 10.1128/jvi.00661-16] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2016] [Accepted: 06/28/2016] [Indexed: 02/07/2023] Open
Abstract
The Nairovirus genus of the Bunyaviridae family contains serious human and animal pathogens classified within multiple serogroups and species. Of these serogroups, the Crimean-Congo hemorrhagic fever virus (CCHFV) serogroup comprises sole members CCHFV and Hazara virus (HAZV). CCHFV is an emerging zoonotic virus that causes often-fatal hemorrhagic fever in infected humans for which preventative or therapeutic strategies are not available. In contrast, HAZV is nonpathogenic to humans and thus represents an excellent model to study aspects of CCHFV biology under conditions of more-accessible biological containment. The three RNA segments that form the nairovirus genome are encapsidated by the viral nucleocapsid protein (N) to form ribonucleoprotein (RNP) complexes that are substrates for RNA synthesis and packaging into virus particles. We used quantitative proteomics to identify cellular interaction partners of CCHFV N and identified robust interactions with cellular chaperones. These interactions were validated using immunological methods, and the specific interaction between native CCHFV N and cellular chaperones of the HSP70 family was confirmed during live CCHFV infection. Using infectious HAZV, we showed for the first time that the nairovirus N-HSP70 association was maintained within both infected cells and virus particles, where N is assembled as RNPs. Reduction of active HSP70 levels in cells by the use of small-molecule inhibitors significantly reduced HAZV titers, and a model for chaperone function in the context of high genetic variability is proposed. These results suggest that chaperones of the HSP70 family are required for nairovirus replication and thus represent a genetically stable cellular therapeutic target for preventing nairovirus-mediated disease. IMPORTANCE Nairoviruses compose a group of human and animal viruses that are transmitted by ticks and associated with serious or fatal disease. One member is Crimean-Congo hemorrhagic fever virus (CCHFV), which is responsible for fatal human disease and is recognized as an emerging threat within Europe in response to climate change. No preventative or therapeutic strategies against nairovirus-mediated disease are currently available. Here we show that the N protein of CCHFV and the related Hazara virus interact with a cellular protein, HSP70, during both the intracellular and extracellular stages of the virus life cycle. The use of inhibitors that block HSP70 function reduces virus titers by up to 1,000-fold, suggesting that this interaction is important within the context of the nairovirus life cycle and may represent a potent target for antinairovirus therapies against which the virus cannot easily develop resistance.
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Organization, Function, and Therapeutic Targeting of the Morbillivirus RNA-Dependent RNA Polymerase Complex. Viruses 2016; 8:v8090251. [PMID: 27626440 PMCID: PMC5035965 DOI: 10.3390/v8090251] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2016] [Revised: 09/02/2016] [Accepted: 09/05/2016] [Indexed: 12/16/2022] Open
Abstract
The morbillivirus genus comprises major human and animal pathogens, including the highly contagious measles virus. Morbilliviruses feature single stranded negative sense RNA genomes that are wrapped by a plasma membrane-derived lipid envelope. Genomes are encapsidated by the viral nucleocapsid protein forming ribonucleoprotein complexes, and only the encapsidated RNA is transcribed and replicated by the viral RNA-dependent RNA polymerase (RdRp). In this review, we discuss recent breakthroughs towards the structural and functional understanding of the morbillivirus polymerase complex. Considering the clinical burden imposed by members of the morbillivirus genus, the development of novel antiviral therapeutics is urgently needed. The viral polymerase complex presents unique structural and enzymatic properties that can serve as attractive candidates for druggable targets. We evaluate distinct strategies for therapeutic intervention and examine how high-resolution insight into the organization of the polymerase complex may pave the path towards the structure-based design and optimization of next-generation RdRp inhibitors.
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Fearns R, Deval J. New antiviral approaches for respiratory syncytial virus and other mononegaviruses: Inhibiting the RNA polymerase. Antiviral Res 2016; 134:63-76. [PMID: 27575793 DOI: 10.1016/j.antiviral.2016.08.006] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2016] [Revised: 07/27/2016] [Accepted: 08/07/2016] [Indexed: 11/16/2022]
Abstract
Worldwide, respiratory syncytial virus (RSV) causes severe disease in infants, the elderly, and immunocompromised people. No vaccine or effective antiviral treatment is available. RSV is a member of the non-segmented, negative-strand (NNS) group of RNA viruses and relies on its RNA-dependent RNA polymerase to transcribe and replicate its genome. Because of its essential nature and unique properties, the RSV polymerase has proven to be a good target for antiviral drugs, with one compound, ALS-8176, having already achieved clinical proof-of-concept efficacy in a human challenge study. In this article, we first provide an overview of the role of the RSV polymerase in viral mRNA transcription and genome replication. We then review past and current approaches to inhibiting the RSV polymerase, including use of nucleoside analogs and non-nucleoside inhibitors. Finally, we consider polymerase inhibitors that hold promise for treating infections with other NNS RNA viruses, including measles and Ebola.
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Affiliation(s)
- Rachel Fearns
- Department of Microbiology, Boston University School of Medicine, Boston, MA, USA.
| | - Jerome Deval
- Alios BioPharma, Inc., Part of the Janssen Pharmaceutical Companies, South San Francisco, CA, USA.
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Deval J, Fung A, Stevens SK, Jordan PC, Gromova T, Taylor JS, Hong J, Meng J, Wang G, Dyatkina N, Prhavc M, Symons JA, Beigelman L. Biochemical Effect of Resistance Mutations against Synergistic Inhibitors of RSV RNA Polymerase. PLoS One 2016; 11:e0154097. [PMID: 27163448 PMCID: PMC4862670 DOI: 10.1371/journal.pone.0154097] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2016] [Accepted: 04/08/2016] [Indexed: 11/18/2022] Open
Abstract
ALS-8112 is the parent molecule of ALS-8176, a first-in-class nucleoside analog prodrug effective in the clinic against respiratory syncytial virus (RSV) infection. The antiviral activity of ALS-8112 is mediated by its 5'-triphosphate metabolite (ALS-8112-TP, or 2'F-4'ClCH2-cytidine triphosphate) inhibiting the RNA polymerase activity of the RSV L-P protein complex through RNA chain termination. Four amino acid mutations in the RNA-dependent RNA polymerase (RdRp) domain of L (QUAD: M628L, A789V, L795I, and I796V) confer in vitro resistance to ALS-8112-TP by increasing its discrimination relative to natural CTP. In this study, we show that the QUAD mutations specifically recognize the ClCH2 group of ALS-8112-TP. Among the four mutations, A789V conferred the greatest resistance phenotype, which was consistent with its putative position in the active site of the RdRp domain. AZ-27, a non-nucleoside inhibitor of RSV, also inhibited the RdRp activity, with decreased inhibition potency in the presence of the Y1631H mutation. The QUAD mutations had no effect on the antiviral activity of AZ-27, and the Y1631H mutation did not significantly increase the discrimination of ALS-8112-TP. Combining ALS-8112 with AZ-27 in vitro resulted in significant synergistic inhibition of RSV replication. Overall, this is the first mechanistic study showing a lack of cross-resistance between mutations selected by different classes of RSV polymerase inhibitors acting in synergy, opening the door to future potential combination therapies targeting different regions of the L protein.
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Affiliation(s)
- Jerome Deval
- Alios BioPharma, Inc., part of the Janssen Pharmaceutical Companies, South San Francisco, California, United States of America
- * E-mail:
| | - Amy Fung
- Alios BioPharma, Inc., part of the Janssen Pharmaceutical Companies, South San Francisco, California, United States of America
| | - Sarah K. Stevens
- Alios BioPharma, Inc., part of the Janssen Pharmaceutical Companies, South San Francisco, California, United States of America
| | - Paul C. Jordan
- Alios BioPharma, Inc., part of the Janssen Pharmaceutical Companies, South San Francisco, California, United States of America
| | - Tatiana Gromova
- Alios BioPharma, Inc., part of the Janssen Pharmaceutical Companies, South San Francisco, California, United States of America
| | - Joshua S. Taylor
- Alios BioPharma, Inc., part of the Janssen Pharmaceutical Companies, South San Francisco, California, United States of America
| | - Jin Hong
- Alios BioPharma, Inc., part of the Janssen Pharmaceutical Companies, South San Francisco, California, United States of America
| | - Jia Meng
- Alios BioPharma, Inc., part of the Janssen Pharmaceutical Companies, South San Francisco, California, United States of America
| | - Guangyi Wang
- Alios BioPharma, Inc., part of the Janssen Pharmaceutical Companies, South San Francisco, California, United States of America
| | - Natalia Dyatkina
- Alios BioPharma, Inc., part of the Janssen Pharmaceutical Companies, South San Francisco, California, United States of America
| | - Marija Prhavc
- Alios BioPharma, Inc., part of the Janssen Pharmaceutical Companies, South San Francisco, California, United States of America
| | - Julian A. Symons
- Alios BioPharma, Inc., part of the Janssen Pharmaceutical Companies, South San Francisco, California, United States of America
| | - Leo Beigelman
- Alios BioPharma, Inc., part of the Janssen Pharmaceutical Companies, South San Francisco, California, United States of America
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Duvall JR, VerPlank L, Ludeke B, McLeod SM, Lee MD, Vishwanathan K, Mulrooney CA, Le Quement S, Yu Q, Palmer MA, Fleming P, Fearns R, Foley MA, Scherer CA. Novel diversity-oriented synthesis-derived respiratory syncytial virus inhibitors identified via a high throughput replicon-based screen. Antiviral Res 2016; 131:19-25. [PMID: 27059228 DOI: 10.1016/j.antiviral.2016.03.015] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2015] [Revised: 03/27/2016] [Accepted: 03/29/2016] [Indexed: 01/23/2023]
Abstract
Respiratory syncytial virus (RSV) infections affect millions of children and adults every year. Despite the significant disease burden, there are currently no safe and effective vaccines or therapeutics. We employed a replicon-based high throughput screen combined with live-virus triaging assays to identify three novel diversity-oriented synthesis-derived scaffolds with activity against RSV. One of these small molecules is shown to target the RSV polymerase (L protein) to inhibit viral replication and transcription; the mechanisms of action of the other small molecules are currently unknown. The compounds described herein may provide attractive inhibitors for lead optimization campaigns.
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Affiliation(s)
- Jeremy R Duvall
- Broad Institute of MIT and Harvard, 415 Main St., Cambridge, MA 02142, United States
| | - Lynn VerPlank
- Broad Institute of MIT and Harvard, 415 Main St., Cambridge, MA 02142, United States
| | - Barbara Ludeke
- Boston University School of Medicine, 72 East Concord Street, Boston, MA 02118, United States
| | - Sarah M McLeod
- AstraZeneca R&D Boston, Infection Innovative Medicines Unit, 35 Gatehouse Drive, Waltham, MA 02451, United States
| | - Maurice D Lee
- Broad Institute of MIT and Harvard, 415 Main St., Cambridge, MA 02142, United States
| | - Karthick Vishwanathan
- AstraZeneca R&D Boston, Early Clinical Development, 35 Gatehouse Drive, Waltham, MA 02451, United States
| | - Carol A Mulrooney
- Broad Institute of MIT and Harvard, 415 Main St., Cambridge, MA 02142, United States
| | - Sebastian Le Quement
- Broad Institute of MIT and Harvard, 415 Main St., Cambridge, MA 02142, United States
| | - Qin Yu
- AstraZeneca R&D Boston, Infection Innovative Medicines Unit, 35 Gatehouse Drive, Waltham, MA 02451, United States
| | - Michelle A Palmer
- Broad Institute of MIT and Harvard, 415 Main St., Cambridge, MA 02142, United States
| | - Paul Fleming
- AstraZeneca R&D Boston, Infection Innovative Medicines Unit, 35 Gatehouse Drive, Waltham, MA 02451, United States
| | - Rachel Fearns
- Boston University School of Medicine, 72 East Concord Street, Boston, MA 02118, United States
| | - Michael A Foley
- Broad Institute of MIT and Harvard, 415 Main St., Cambridge, MA 02142, United States
| | - Christina A Scherer
- Broad Institute of MIT and Harvard, 415 Main St., Cambridge, MA 02142, United States.
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Therapeutic efficacy of the small molecule GS-5734 against Ebola virus in rhesus monkeys. Nature 2016; 531:381-5. [PMID: 26934220 PMCID: PMC5551389 DOI: 10.1038/nature17180] [Citation(s) in RCA: 1036] [Impact Index Per Article: 129.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2015] [Accepted: 01/29/2016] [Indexed: 12/12/2022]
Abstract
The discovery is reported of a small molecule drug, GS-5734, which has antiviral activity against Ebola virus and other filoviruses, and is capable of providing post-exposure therapeutic protection against lethal disease in 100% of drug-treated nonhuman primates infected with Ebola virus; the drug targets viral RNA polymerase and can distribute to sanctuary sites (such as testes, eyes and brain), suggesting that it may be able to clear persistent virus infection. These authors report the discovery of a small-molecule drug, GS-5734, which has antiviral activity against Ebola and other filoviruses, and is capable of providing post-exposure protection against Ebola virus in 100% of infected macaques tested. Now in clinical trials (http://go.nature.com/PEW2Oi), the drug targets the viral RNA-dependent RNA polymerase and is readily scalable for future outbreaks. GS-5734 is able to distribute to sanctuary sites for viral replication including the testes, eye and brain, offering the hope that this drug may also be able to clear recrudescent and persistent virus infection. The most recent Ebola virus outbreak in West Africa, which was unprecedented in the number of cases and fatalities, geographic distribution, and number of nations affected, highlights the need for safe, effective, and readily available antiviral agents for treatment and prevention of acute Ebola virus (EBOV) disease (EVD) or sequelae1. No antiviral therapeutics have yet received regulatory approval or demonstrated clinical efficacy. Here we report the discovery of a novel small molecule GS-5734, a monophosphoramidate prodrug of an adenosine analogue, with antiviral activity against EBOV. GS-5734 exhibits antiviral activity against multiple variants of EBOV and other filoviruses in cell-based assays. The pharmacologically active nucleoside triphosphate (NTP) is efficiently formed in multiple human cell types incubated with GS-5734 in vitro, and the NTP acts as an alternative substrate and RNA-chain terminator in primer-extension assays using a surrogate respiratory syncytial virus RNA polymerase. Intravenous administration of GS-5734 to nonhuman primates resulted in persistent NTP levels in peripheral blood mononuclear cells (half-life, 14 h) and distribution to sanctuary sites for viral replication including testes, eyes, and brain. In a rhesus monkey model of EVD, once-daily intravenous administration of 10 mg kg−1 GS-5734 for 12 days resulted in profound suppression of EBOV replication and protected 100% of EBOV-infected animals against lethal disease, ameliorating clinical disease signs and pathophysiological markers, even when treatments were initiated three days after virus exposure when systemic viral RNA was detected in two out of six treated animals. These results show the first substantive post-exposure protection by a small-molecule antiviral compound against EBOV in nonhuman primates. The broad-spectrum antiviral activity of GS-5734 in vitro against other pathogenic RNA viruses, including filoviruses, arenaviruses, and coronaviruses, suggests the potential for wider medical use. GS-5734 is amenable to large-scale manufacturing, and clinical studies investigating the drug safety and pharmacokinetics are ongoing.
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McKimm-Breschkin JL, Fry AM. Meeting report: 4th ISIRV antiviral group conference: Novel antiviral therapies for influenza and other respiratory viruses. Antiviral Res 2016; 129:21-38. [PMID: 26872862 PMCID: PMC7132401 DOI: 10.1016/j.antiviral.2016.01.012] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2016] [Accepted: 01/22/2016] [Indexed: 01/08/2023]
Abstract
The International Society for Influenza and other Respiratory Virus Diseases (isirv) held its 4th Antiviral Group Conference at the University of Texas on 2–4 June, 2015. With emerging resistance to the drugs currently licensed for treatment and prophylaxis of influenza viruses, primarily the neuraminidase inhibitor oseltamivir phosphate (Tamiflu) and the M2 inhibitors amantadine and rimantadine, and the lack of effective interventions against other respiratory viruses, the 3-day programme focused on the discovery and development of inhibitors of several virus targets and key host cell factors involved in virus replication or mediating the inflammatory response. Virus targets included the influenza haemagglutinin, neuraminidase and M2 proteins, and both the respiratory syncytial virus and influenza polymerases and nucleoproteins. Therapies for rhinoviruses and MERS and SARS coronaviruses were also discussed. With the emerging development of monoclonal antibodies as therapeutics, the potential implications of antibody-dependent enhancement of disease were also addressed. Topics covered all aspects from structural and molecular biology to preclinical and clinical studies. The importance of suitable clinical trial endpoints and regulatory issues were also discussed from the perspectives of both industry and government. This meeting summary provides an overview, not only for the conference participants, but also for those interested in the current status of antivirals for respiratory viruses. The International Society for Influenza and other Respiratory Viruses held an Antiviral Group conference in June, 2015. This report covers oral presentations, including therapies against influenza and respiratory syncytial virus infections. Therapies for rhinovirus, MERS and SARS coronavirus infections were also topics at the conference. Some speakers focused on monoclonal antibodies as therapeutics and antibody-dependent enhancement of disease. The importance of suitable clinical trial endpoints and regulatory issues were also discussed.
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Affiliation(s)
| | - Alicia M Fry
- Influenza Division, Centers for Disease Control and Prevention, Atlanta, GA, USA.
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The Interferon Type I/III Response to Respiratory Syncytial Virus Infection in Airway Epithelial Cells Can Be Attenuated or Amplified by Antiviral Treatment. J Virol 2015; 90:1705-17. [PMID: 26608311 DOI: 10.1128/jvi.02417-15] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2015] [Accepted: 11/16/2015] [Indexed: 12/13/2022] Open
Abstract
UNLABELLED Human respiratory syncytial virus (RSV) is a single-stranded RNA virus that causes acute, and occasionally fatal, lower respiratory illness in young infants, the elderly, and immunocompromised patients. Therapeutic interventions able to cut short viral replication and quickly return the airways to normal function are needed. An understanding of antiviral activities and their effects on host defense mechanisms is important for the design of safe and effective therapy. We targeted functionally and temporally distinct steps within the viral life cycle using small-molecule RSV inhibitors and studied their antiviral activities and their effects on innate interferon responses of airway epithelial cells in vitro. Antivirals acting upstream of RSV polymerase activity (i.e., compounds targeting the fusion protein or the nucleoprotein) reduced viral load immediately postinfection and partially attenuated interferon responses. In contrast, antivirals directed to the RSV polymerase demonstrated activity throughout the viral replication cycle and specifically modulated the RIG-I/mitochondrial antiviral signaling protein (MAVS)/TBK1/IRF3/interferon-stimulated gene (ISG) axis, causing either an upregulation or a downregulation of interferon responses, depending on the mechanism of polymerase inhibition. Notably, polymerase inhibition leading to the accumulation of abortive RNA products correlated with the amplification of interferon-stimulated genes to up to 10 times above normal infection levels. Understanding how antiviral activities and their modulation of innate immunity may affect recovery from RSV infection will help guide the development of safe and effective therapies. IMPORTANCE RSV circulates seasonally, causing acute lower respiratory disease. Therapeutic interventions with efficacy throughout the viral replication cycle, rapid viral clearance, and prevention of potentially harmful inflammatory responses are desirable. Compounds targeting the RSV polymerase inhibited virus replication late in the viral life cycle and, depending on the functional domain targeted, either attenuated or amplified RIG-I and downstream interferon pathways in infected cells. These data will help guide the development of safe and effective therapies by providing new molecular evidence that the mechanism of inhibition by an antiviral compound can directly impact innate antiviral immune responses in the airway epithelium.
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Rivera CA, Gómez RS, Díaz RA, Céspedes PF, Espinoza JA, González PA, Riedel CA, Bueno SM, Kalergis AM. Novel therapies and vaccines against the human respiratory syncytial virus. Expert Opin Investig Drugs 2015; 24:1613-30. [DOI: 10.1517/13543784.2015.1099626] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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