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Wolf JD, Sirrine MR, Cox RM, Plemper RK. Structural basis of paramyxo- and pneumovirus polymerase inhibition by non-nucleoside small-molecule antivirals. Antimicrob Agents Chemother 2024; 68:e0080024. [PMID: 39162479 PMCID: PMC11459973 DOI: 10.1128/aac.00800-24] [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: 08/21/2024] Open
Abstract
Small-molecule antivirals can be used as chemical probes to stabilize transitory conformational stages of viral target proteins, facilitating structural analyses. Here, we evaluate allosteric pneumo- and paramyxovirus polymerase inhibitors that have the potential to serve as chemical probes and aid the structural characterization of short-lived intermediate conformations of the polymerase complex. Of multiple inhibitor classes evaluated, we discuss in-depth distinct scaffolds that were selected based on well-understood structure-activity relationships, insight into resistance profiles, biochemical characterization of the mechanism of action, and photoaffinity-based target mapping. Each class is thought to block structural rearrangements of polymerase domains albeit target sites and docking poses are distinct. This review highlights validated druggable targets in the paramyxo- and pneumovirus polymerase proteins and discusses discrete structural stages of the polymerase complexes required for bioactivity.
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Affiliation(s)
- Josef D. Wolf
- Center for Translational Antiviral Research, Georgia State University Institute for Biomedical Sciences, Atlanta, Georgia, USA
| | - Michael R. Sirrine
- Center for Translational Antiviral Research, Georgia State University Institute for Biomedical Sciences, Atlanta, Georgia, USA
| | - Robert M. Cox
- Center for Translational Antiviral Research, Georgia State University Institute for Biomedical Sciences, Atlanta, Georgia, USA
| | - Richard K. Plemper
- Center for Translational Antiviral Research, Georgia State University Institute for Biomedical Sciences, Atlanta, Georgia, USA
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2
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Schmitz KS, Lange MV, Gommers L, Handrejk K, Porter DP, Alabi CA, Moscona A, Porotto M, de Vries RD, de Swart RL. Repurposing an In Vitro Measles Virus Dissemination Assay for Screening of Antiviral Compounds. Viruses 2022; 14:v14061186. [PMID: 35746658 PMCID: PMC9230603 DOI: 10.3390/v14061186] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2022] [Revised: 05/25/2022] [Accepted: 05/25/2022] [Indexed: 02/04/2023] Open
Abstract
Measles virus (MV) is a highly contagious respiratory virus responsible for outbreaks associated with significant morbidity and mortality among children and young adults. Although safe and effective measles vaccines are available, the COVID-19 pandemic has resulted in vaccination coverage gaps that may lead to the resurgence of measles when restrictions are lifted. This puts individuals who cannot be vaccinated, such as young infants and immunocompromised individuals, at risk. Therapeutic interventions are complicated by the long incubation time of measles, resulting in a narrow treatment window. At present, the only available WHO-advised option is treatment with intravenous immunoglobulins, although this is not approved as standard of care. Antivirals against measles may contribute to intervention strategies to limit the impact of future outbreaks. Here, we review previously described antivirals and antiviral assays, evaluate the antiviral efficacy of a number of compounds to inhibit MV dissemination in vitro, and discuss potential application in specific target populations. We conclude that broadly reactive antivirals could strengthen existing intervention strategies to limit the impact of measles outbreaks.
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Affiliation(s)
- Katharina S. Schmitz
- Department of Viroscience, Erasmus MC, 3015 GD Rotterdam, The Netherlands; (K.S.S.); (M.V.L.); (L.G.); (K.H.); (R.D.d.V.)
| | - Mona V. Lange
- Department of Viroscience, Erasmus MC, 3015 GD Rotterdam, The Netherlands; (K.S.S.); (M.V.L.); (L.G.); (K.H.); (R.D.d.V.)
| | - Lennert Gommers
- Department of Viroscience, Erasmus MC, 3015 GD Rotterdam, The Netherlands; (K.S.S.); (M.V.L.); (L.G.); (K.H.); (R.D.d.V.)
| | - Kim Handrejk
- Department of Viroscience, Erasmus MC, 3015 GD Rotterdam, The Netherlands; (K.S.S.); (M.V.L.); (L.G.); (K.H.); (R.D.d.V.)
| | | | - Christopher A. Alabi
- Robert Frederick Smith School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, NY 14850, USA;
| | - Anne Moscona
- Department of Pediatrics, Columbia University Medical Center, New York, NY 10032, USA; (A.M.); (M.P.)
- Center for Host–Pathogen Interaction, Columbia University Irving Medical Center, New York, NY 10032, USA
- Department of Physiology and Cellular Biophysics, Columbia University Irving Medical Center, New York, NY 10032, USA
- Department of Microbiology and Immunology, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Matteo Porotto
- Department of Pediatrics, Columbia University Medical Center, New York, NY 10032, USA; (A.M.); (M.P.)
- Center for Host–Pathogen Interaction, Columbia University Irving Medical Center, New York, NY 10032, USA
- Department of Experimental Medicine, University of Campania “Luigi Vanvitelli”, 81100 Caserta, Italy
| | - Rory D. de Vries
- Department of Viroscience, Erasmus MC, 3015 GD Rotterdam, The Netherlands; (K.S.S.); (M.V.L.); (L.G.); (K.H.); (R.D.d.V.)
| | - Rik L. de Swart
- Department of Viroscience, Erasmus MC, 3015 GD Rotterdam, The Netherlands; (K.S.S.); (M.V.L.); (L.G.); (K.H.); (R.D.d.V.)
- Correspondence:
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3
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Wittwer K, Anderson DE, Pfeffermann K, Cox RM, Wolf JD, Santibanez S, Mankertz A, Plesker R, Sticher ZM, Kolkykhalov AA, Natchus MG, Pfaller CK, Plemper RK, von Messling V. Small-molecule polymerase inhibitor protects non-human primates from measles and reduces shedding. Nat Commun 2021; 12:5233. [PMID: 34475387 PMCID: PMC8413292 DOI: 10.1038/s41467-021-25497-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Accepted: 08/12/2021] [Indexed: 01/26/2023] Open
Abstract
Measles virus (MeV) is a highly contagious pathogen that enters the human host via the respiratory route. Besides acute pathologies including fever, cough and the characteristic measles rash, the infection of lymphocytes leads to substantial immunosuppression that can exacerbate the outcome of infections with additional pathogens. Despite the availability of effective vaccine prophylaxis, measles outbreaks continue to occur worldwide. We demonstrate that prophylactic and post-exposure therapeutic treatment with an orally bioavailable small-molecule polymerase inhibitor, ERDRP-0519, prevents measles disease in squirrel monkeys (Saimiri sciureus). Treatment initiation at the onset of clinical signs reduced virus shedding, which may support outbreak control. Results show that this clinical candidate has the potential to alleviate clinical measles and augment measles virus eradication. Measles virus is highly contagious and outbreaks occur worldwide. Here the authors show that the orally bioavailable small-molecule polymerase inhibitor ERDRP-0519 prevents measles disease in squirrel monkeys and reduces virus shedding.
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Affiliation(s)
- Kevin Wittwer
- Veterinary Medicine Division, Paul-Ehrlich-Institute, Langen, Germany
| | - Danielle E Anderson
- Programme in Emerging Infectious Diseases, Duke-NUS Medical School, Singapore, Singapore
| | | | - Robert M Cox
- Institute for Biomedical Sciences, Georgia State University, Atlanta, GA, USA
| | - Josef D Wolf
- Institute for Biomedical Sciences, Georgia State University, Atlanta, GA, USA
| | - Sabine Santibanez
- WHO European Regional Reference Laboratory for Measles and Rubella, Robert Koch-Institute, Berlin, Germany
| | - Annette Mankertz
- WHO European Regional Reference Laboratory for Measles and Rubella, Robert Koch-Institute, Berlin, Germany
| | - Roland Plesker
- Veterinary Medicine Division, Paul-Ehrlich-Institute, Langen, Germany
| | - Zachary M Sticher
- Emory Institute for Drug Development, Emory University, Atlanta, GA, USA
| | | | - Michael G Natchus
- Emory Institute for Drug Development, Emory University, Atlanta, GA, USA
| | | | - Richard K Plemper
- Institute for Biomedical Sciences, Georgia State University, Atlanta, GA, USA.
| | - Veronika von Messling
- Veterinary Medicine Division, Paul-Ehrlich-Institute, Langen, Germany.,Life Sciences Unit, Federal Ministry of Education and Research, Berlin, Germany
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4
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Kumar R, Mishra S, Shreya, Maurya SK. Recent advances in the discovery of potent RNA-dependent RNA-polymerase (RdRp) inhibitors targeting viruses. RSC Med Chem 2021; 12:306-320. [PMID: 34046618 PMCID: PMC8130609 DOI: 10.1039/d0md00318b] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Accepted: 11/26/2020] [Indexed: 12/31/2022] Open
Abstract
WHO has declared COVID-19 a pandemic, which has affected the whole world and has caused unprecedented social and economic disruption. Since the emergence of the disease, several druggable targets have been suggested including 3-chymotrypsin-like protease (3CLpro), spike, RNA-dependent RNA polymerase (RdRp), and the papain-like protease (PLpro) computational approach. From the beginning, viral replication has been the main focus for any antiviral drug development for viral diseases, including HCV, influenza virus, zika virus, norovirus, measles, dengue virus, and coronaviruses. This review lists the nucleoside, nucleotide, and non-nucleoside RdRp inhibitor analogues of various viral diseases that may be evaluated for drug development to treat COVID-19.
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Affiliation(s)
- Rahul Kumar
- Chemical Technology Division, CSIR-Institute of Himalayan Bioresource Technology Palampur Himachal Pradesh-176 061 India
- Academy of Scientific and Innovative Research, CSIR-HRDC Ghaziabad Uttar Pradesh 201 002 India
| | - Sahil Mishra
- Chemical Technology Division, CSIR-Institute of Himalayan Bioresource Technology Palampur Himachal Pradesh-176 061 India
| | - Shreya
- Chemical Technology Division, CSIR-Institute of Himalayan Bioresource Technology Palampur Himachal Pradesh-176 061 India
| | - Sushil K Maurya
- Chemical Technology Division, CSIR-Institute of Himalayan Bioresource Technology Palampur Himachal Pradesh-176 061 India
- Academy of Scientific and Innovative Research, CSIR-HRDC Ghaziabad Uttar Pradesh 201 002 India
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5
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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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6
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Hashimoto K, Hosoya M. Advances in Antiviral Therapy for Subacute Sclerosing Panencephalitis. Molecules 2021; 26:molecules26020427. [PMID: 33467470 PMCID: PMC7830519 DOI: 10.3390/molecules26020427] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2020] [Revised: 01/09/2021] [Accepted: 01/12/2021] [Indexed: 12/17/2022] Open
Abstract
Subacute sclerosing panencephalitis (SSPE) is a late-onset, intractable, and fatal viral disease caused by persistent infection of the central nervous system by a mutant strain of the measles virus. Ribavirin intracerebroventricular therapy has already been administered to several SSPE patients in Japan based on fundamental and clinical research findings from our group, with positive therapeutic effects reported in some patients. However, the efficacy of this treatment approach has not been unequivocally established. Hence, development of more effective therapeutic methods using new antiviral agents is urgently needed. This review describes the current status of SSPE treatment and research, highlighting promising approaches to the development of more effective therapeutic methods.
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7
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Nuphar lutea Extracts Exhibit Anti-Viral Activity against the Measles Virus. Molecules 2020; 25:molecules25071657. [PMID: 32260270 PMCID: PMC7180909 DOI: 10.3390/molecules25071657] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2020] [Revised: 03/22/2020] [Accepted: 04/02/2020] [Indexed: 02/06/2023] Open
Abstract
Different parts of Nuphar lutea L. (yellow water lily) have been used to treat several inflammatory and pathogen-related diseases. It has shown that Nuphar lutea extracts (NUP) are active against various pathogens including bacteria, fungi, and leishmanial parasites. In an effort to detect novel therapeutic agents against negative-stranded RNA (- RNA) viruses, we have tested the effect of a partially-purified alkaloid mixture of Nuphar lutea leaves on the measles virus (MV). The MV vaccine’s Edmonston strain was used to acutely or persistently infect cells. The levels of several MV proteins were detected by a Western blot and immunocytochemistry. Viral RNAs were quantitated by qRT-PCR. Virus infectivity was monitored by infecting African green monkey kidney VERO cells’ monolayers. We showed that NUP protected cells from acute infection. Decreases in the MV P-, N-, and V-proteins were observed in persistently infected cells and the amount of infective virus released was reduced as compared to untreated cells. By examining viral RNAs, we suggest that NUP acts at the post-transcriptional level. We conclude, as a proof of concept, that NUP has anti-viral therapeutic activity against the MV. Future studies will determine the mechanism of action and the effect of NUP on other related viruses.
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8
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Plemper RK. Measles Resurgence and Drug Development. Curr Opin Virol 2020; 41:8-17. [PMID: 32247280 DOI: 10.1016/j.coviro.2020.02.007] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2019] [Revised: 02/19/2020] [Accepted: 02/24/2020] [Indexed: 12/16/2022]
Abstract
Measles caused an estimated minimum of one million fatalities annually before vaccination. Outstanding progress towards controlling the virus has been made since the measles vaccine was introduced, but reduction of measles case-fatalities has stalled at around 100,000 annually for the last decade and a 2019 resurgence in several geographical regions threatens some of these past accomplishments. Whereas measles eradication through vaccination is feasible, a potentially open-ended endgame of elimination may loom. Other than doubling-down on existing approaches, is it worthwhile to augment vaccination efforts with antiviral therapeutics to solve the conundrum? This question is hypothetical at present, since no drugs have yet been approved specifically for the treatment of measles, or infection by any other pathogen of the paramyxovirus family. This article will consider obstacles that have hampered anti-measles and anti-paramyxovirus drug development, discuss MeV-specific challenges of clinical testing, and define drug properties suitable to address some of these problems.
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Affiliation(s)
- Richard K Plemper
- Institute for Biomedical Sciences, Georgia State University, Atlanta, GA 30303, USA.
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9
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Ferren M, Horvat B, Mathieu C. Measles Encephalitis: Towards New Therapeutics. Viruses 2019; 11:E1017. [PMID: 31684034 PMCID: PMC6893791 DOI: 10.3390/v11111017] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Revised: 10/25/2019] [Accepted: 10/31/2019] [Indexed: 12/20/2022] Open
Abstract
Measles remains a major cause of morbidity and mortality worldwide among vaccine preventable diseases. Recent decline in vaccination coverage resulted in re-emergence of measles outbreaks. Measles virus (MeV) infection causes an acute systemic disease, associated in certain cases with central nervous system (CNS) infection leading to lethal neurological disease. Early following MeV infection some patients develop acute post-infectious measles encephalitis (APME), which is not associated with direct infection of the brain. MeV can also infect the CNS and cause sub-acute sclerosing panencephalitis (SSPE) in immunocompetent people or measles inclusion-body encephalitis (MIBE) in immunocompromised patients. To date, cellular and molecular mechanisms governing CNS invasion are still poorly understood. Moreover, the known MeV entry receptors are not expressed in the CNS and how MeV enters and spreads in the brain is not fully understood. Different antiviral treatments have been tested and validated in vitro, ex vivo and in vivo, mainly in small animal models. Most treatments have high efficacy at preventing infection but their effectiveness after CNS manifestations remains to be evaluated. This review describes MeV neural infection and current most advanced therapeutic approaches potentially applicable to treat MeV CNS infection.
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Affiliation(s)
- Marion Ferren
- CIRI, International Center for Infectiology Research, INSERM U1111, University of Lyon, University Claude Bernard Lyon 1, CNRS, UMR5308, Ecole Normale Supérieure de Lyon, France.
| | - Branka Horvat
- CIRI, International Center for Infectiology Research, INSERM U1111, University of Lyon, University Claude Bernard Lyon 1, CNRS, UMR5308, Ecole Normale Supérieure de Lyon, France.
| | - Cyrille Mathieu
- CIRI, International Center for Infectiology Research, INSERM U1111, University of Lyon, University Claude Bernard Lyon 1, CNRS, UMR5308, Ecole Normale Supérieure de Lyon, France.
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10
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Fearns R, Plemper RK. Polymerases of paramyxoviruses and pneumoviruses. Virus Res 2017; 234:87-102. [PMID: 28104450 DOI: 10.1016/j.virusres.2017.01.008] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2016] [Revised: 01/06/2017] [Accepted: 01/09/2017] [Indexed: 11/13/2022]
Abstract
The paramyxo- and pneumoviruses are members of the order Mononegavirales, a group of viruses with non-segmented, negative strand RNA genomes. The polymerases of these viruses are multi-functional complexes, capable of transcribing subgenomic capped and polyadenylated mRNAs and replicating the genome. Although there is no native structure available for any complete paramyxo- or pneumovirus polymerase, functional and structural studies of a fragment of a pneumovirus polymerase protein and mutation analyses and resistance profiling of small-molecule inhibitors have generated a wealth of mechanistic information. This review integrates these data with the structure of a related polymerase, identifying similarities, differences, gaps in knowledge, and avenues for antiviral drug development.
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Affiliation(s)
- Rachel Fearns
- Department of Microbiology, Boston University School of Medicine, Boston, MA 02118, United States.
| | - Richard K Plemper
- Institute for Biomedical Sciences, Georgia State University, Atlanta, GA 30303, United States
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11
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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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12
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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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13
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Cox R, Plemper RK. Structure-guided design of small-molecule therapeutics against RSV disease. Expert Opin Drug Discov 2016; 11:543-556. [PMID: 27046051 PMCID: PMC5074927 DOI: 10.1517/17460441.2016.1174212] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
INTRODUCTION In the United States, respiratory syncytial virus (RSV) is responsible for the majority of infant hospitalizations resulting from viral infections, as well as a leading source of pneumonia and bronchiolitis in young children and the elderly. In the absence of vaccine prophylaxis or an effective antiviral for improved disease management, the development of novel anti-RSV therapeutics is critical. Several advanced drug development campaigns of the past decade have focused on blocking viral infection. These efforts have returned a chemically distinct panel of small-molecule RSV entry inhibitors, but binding sites and molecular mechanism of action appeared to share a common mechanism, resulting in comprehensive cross-resistance and calling for alternative druggable targets such as viral RNA-dependent RNA-polymerase complex. Areas Covered: In this review, the authors discuss the current status of the mechanism of action of RSV entry inhibitors. They also provide the recent structural insight into the organization of the polymerase complex that have revealed novel drug targets sites, and outline a path towards the discovery of next-generation RSV therapeutics. Expert opinion: Considering the tremendous progress experienced in our structural understanding of RSV biology in recent years and encouraging early results of a nucleoside analog inhibitor in clinical trials, there is high prospect that new generations of much needed effective anti-RSV therapeutics will become available for clinical use in the foreseeable future.
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Affiliation(s)
- Robert Cox
- Institute for Biomedical Sciences, Georgia State University, 100 Piedmont Av, Atlanta, Georgia 30303-3222 USA
| | - Richard K Plemper
- Institute for Biomedical Sciences, Georgia State University, 100 Piedmont Av, Atlanta, Georgia 30303-3222 USA
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14
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Yan D, Weisshaar M, Lamb K, Chung HK, Lin MZ, Plemper RK. Replication-Competent Influenza Virus and Respiratory Syncytial Virus Luciferase Reporter Strains Engineered for Co-Infections Identify Antiviral Compounds in Combination Screens. Biochemistry 2015; 54:5589-604. [PMID: 26307636 PMCID: PMC4719150 DOI: 10.1021/acs.biochem.5b00623] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Myxoviruses such as influenza A virus (IAV) and respiratory syncytial virus (RSV) are major human pathogens, mandating the development of novel therapeutics. To establish a high-throughput screening protocol for the simultaneous identification of pathogen- and host-targeted hit candidates against either pathogen or both, we have attempted co-infection of cells with IAV and RSV. However, viral replication kinetics were incompatible, RSV signal window was low, and an IAV-driven minireplicon reporter assay used in initial screens narrowed the host cell range and restricted the assay to single-cycle infections. To overcome these limitations, we developed an RSV strain carrying firefly luciferase fused to an innovative universal small-molecule assisted shut-off domain, which boosted assay signal window, and a hyperactive fusion protein that synchronized IAV and RSV reporter expression kinetics and suppressed the identification of RSV entry inhibitors sensitive to a recently reported RSV pan-resistance mechanism. Combined with a replication-competent recombinant IAV strain harboring nanoluciferase, the assay performed well on a human respiratory cell line and supports multicycle infections. Miniaturized to 384-well format, the protocol was validated through screening of a set of the National Institutes of Health Clinical Collection (NCC) in quadruplicate. These test screens demonstrated favorable assay parameters and reproducibility. Application to a LOPAC library of bioactive compounds in a proof-of-concept campaign detected licensed antimyxovirus therapeutics, ribavirin and the neuraminidase inhibitor zanamivir, and identified two unexpected RSV-specific hit candidates, Fenretinide and the opioid receptor antagonist BNTX-7. Hits were evaluated in direct and orthogonal dose-response counterscreens using a standard recRSV reporter strain expressing Renilla luciferase.
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Affiliation(s)
- Dan Yan
- Institute for Biomedical Sciences, Georgia State University, Atlanta, GA
| | - Marco Weisshaar
- Institute for Biomedical Sciences, Georgia State University, Atlanta, GA
| | - Kristen Lamb
- Institute for Biomedical Sciences, Georgia State University, Atlanta, GA
| | | | - Michael Z Lin
- Department of Bioengineering, Stanford University, Stanford, CA
- Department of Pediatrics, Stanford University, Stanford, CA
| | - Richard K Plemper
- Institute for Biomedical Sciences, Georgia State University, Atlanta, GA
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15
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Perwitasari O, Tripp RA. A pioneering countermeasure against measles virus. ANNALS OF TRANSLATIONAL MEDICINE 2015; 3:S15. [PMID: 26046060 DOI: 10.3978/j.issn.2305-5839.2015.02.29] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Subscribe] [Scholar Register] [Received: 01/23/2015] [Accepted: 02/06/2015] [Indexed: 11/14/2022]
Affiliation(s)
- Olivia Perwitasari
- Department of Infectious Diseases, University of Georgia College of Veterinary Medicine, Athens, Georgia, USA
| | - Ralph A Tripp
- Department of Infectious Diseases, University of Georgia College of Veterinary Medicine, Athens, Georgia, USA
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16
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Cox R, Plemper RK. The paramyxovirus polymerase complex as a target for next-generation anti-paramyxovirus therapeutics. Front Microbiol 2015; 6:459. [PMID: 26029193 PMCID: PMC4428208 DOI: 10.3389/fmicb.2015.00459] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2015] [Accepted: 04/27/2015] [Indexed: 12/04/2022] Open
Abstract
The paramyxovirus family includes major human and animal pathogens, including measles virus, mumps virus, and human respiratory syncytial virus (RSV), as well as the emerging zoonotic Hendra and Nipah viruses. In the U.S., RSV is the leading cause of infant hospitalizations due to viral infectious disease. Despite their clinical significance, effective drugs for the improved management of paramyxovirus disease are lacking. The development of novel anti-paramyxovirus therapeutics is therefore urgently needed. Paramyxoviruses contain RNA genomes of negative polarity, necessitating a virus-encoded RNA-dependent RNA polymerase (RdRp) complex for replication and transcription. Since an equivalent enzymatic activity is absent in host cells, the RdRp complex represents an attractive druggable target, although structure-guided drug development campaigns are hampered by the lack of high-resolution RdRp crystal structures. Here, we review the current structural and functional insight into the paramyxovirus polymerase complex in conjunction with an evaluation of the mechanism of activity and developmental status of available experimental RdRp inhibitors. Our assessment spotlights the importance of the RdRp complex as a premier target for therapeutic intervention and examines how high-resolution insight into the organization of the complex will pave the path toward the structure-guided design and optimization of much-needed next-generation paramyxovirus RdRp blockers.
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Affiliation(s)
- Robert Cox
- Institute for Biomedical Sciences, Petit Science Center, Georgia State University, Atlanta, GA USA
| | - Richard K Plemper
- Institute for Biomedical Sciences, Petit Science Center, Georgia State University, Atlanta, GA USA
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17
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Krumm SA, Yan D, Hovingh ES, Evers TJ, Enkirch T, Reddy GP, Sun A, Saindane MT, Arrendale RF, Painter G, Liotta DC, Natchus MG, von Messling V, Plemper RK. An orally available, small-molecule polymerase inhibitor shows efficacy against a lethal morbillivirus infection in a large animal model. Sci Transl Med 2014; 6:232ra52. [PMID: 24739760 DOI: 10.1126/scitranslmed.3008517] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Measles virus is a highly infectious morbillivirus responsible for major morbidity and mortality in unvaccinated humans. The related, zoonotic canine distemper virus (CDV) induces morbillivirus disease in ferrets with 100% lethality. We report an orally available, shelf-stable pan-morbillivirus inhibitor that targets the viral RNA polymerase. Prophylactic oral treatment of ferrets infected intranasally with a lethal CDV dose reduced viremia and prolonged survival. Ferrets infected with the same dose of virus that received post-infection treatment at the onset of viremia showed low-grade viral loads, remained asymptomatic, and recovered from infection, whereas control animals succumbed to the disease. Animals that recovered also mounted a robust immune response and were protected against rechallenge with a lethal CDV dose. Drug-resistant viral recombinants were generated and found to be attenuated and transmission-impaired compared to the genetic parent virus. These findings may pioneer a path toward an effective morbillivirus therapy that could aid measles eradication by synergizing with vaccination to close gaps in herd immunity due to vaccine refusal.
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Affiliation(s)
- Stefanie A Krumm
- Institute for Biomedical Sciences, Georgia State University, Atlanta, GA 30303, USA
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18
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Grimmer C, Moore TW, Padwa A, Prussia A, Wells G, Wu S, Sun A, Snyder JP. Antiviral atropisomers: conformational energy surfaces by NMR for host-directed myxovirus blockers. J Chem Inf Model 2014; 54:2214-23. [PMID: 25058809 DOI: 10.1021/ci500204j] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Biologically active organic molecules characterized by a high single bond torsional barrier generate isolable isomers (atropisomers) and offer a unique stereochemical component to the design of selective therapeutic agents. The present work presents a nanomolar active inhibitor of myxoviruses, which most likely acts by blocking one or more cellular host proteins but also, serendipitously, exhibits axial chirality with an energy barrier of ΔG((++)) ≥30 kcal/mol. The latter has been probed by variable temperature NMR and microwave irradiation and by high level DFT transition state analysis and force field calculations. Full conformational profiles of the corresponding (aR,S) and (aS,S) atropisomers at ambient temperature were derived by conformer deconvolution with NAMFIS (NMR Analysis by Molecular Flexibility In Solution) methodology to generate seven and eight individual conformations, each assigned a % population. An accurate evaluation of a key torsion angle at the center of the molecules associated with a (3)JC-S-C-H coupling constant was obtained by mapping the S-C bond rotation with the MPW1PW91/6-31G-d,p DFT method followed by fitting the resulting dihedral angles and J-values to a Karplus expression. Accordingly, we have developed a complete conformational profile of diastereomeric atropisomers consistent with both high and low rotational barriers. We expect this assessment to assist the rationalization of the selectivity of the two (aR,S) and (aS,S) forms against host proteins, while offering insights into their divergent toxicity behavior.
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Affiliation(s)
- Craig Grimmer
- School of Chemistry and Physics, University of KwaZulu-Natal , Pietermaritzburg, South Africa
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19
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Abstract
INTRODUCTION The measles virus is a major human pathogen responsible for approximately 150,000 deaths annually. The disease is vaccine preventable and eradication of the virus is considered feasible, in principle. However, a herd immunity exceeding 95% is required to prevent sporadic viral outbreaks in a population. Declining disease prevalence, combined with public anxiety over the vaccination's safety, has led to increased vaccine refusal, especially in Europe. This has led to the resurgence of measles in some areas. AREAS COVERED This article discusses whether synergizing effective measles therapeutics with the measles vaccination could contribute to finally eradicating measles. The authors identify key elements in a desirable drug profile and review current disease management strategies and the state of experimental inhibitor candidates. The authors also evaluate the risk associated with viral escape from inhibition, and consider the potential of measles therapeutics in the management of persistent central nervous system (CNS) viral infection. Finally, the authors contemplate the possible impact of therapeutics in controlling the threat imposed by closely related zoonotic pathogens of the same genus as measles. EXPERT OPINION Efficacious therapeutics used for post-exposure prophylaxis of high-risk social contacts of confirmed index cases may aid measles eradication by closing herd immunity gaps; this is due to vaccine refusal or failure in populations with overall good vaccination coverage. The envisioned primarily prophylactic application of measles therapeutics to a predominantly pediatric and/or adolescent population, dictates the drug profile. It also has to be safe and efficacious, orally available, shelf-stable at ambient temperature and amenable to cost-effective manufacturing.
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Affiliation(s)
- Richard K Plemper
- Georgia State University, Center for Inflammation, Immunity & Infection, Petit Science Center, 712 100 Piedmont Av, Atlanta, GA 30303 , USA +1 404 413 3579 ;
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20
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Dual myxovirus screen identifies a small-molecule agonist of the host antiviral response. J Virol 2013; 87:11076-87. [PMID: 23926334 DOI: 10.1128/jvi.01425-13] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
As we are confronted with an increasing number of emerging and reemerging viral pathogens, the identification of novel pathogen-specific and broad-spectrum antivirals has become a major developmental objective. Targeting of host factors required for virus replication presents a tangible approach toward obtaining novel hits with a broadened indication range. However, the identification of developable host-directed antiviral candidates remains challenging. We describe a novel screening protocol that interrogates the myxovirus host-pathogen interactome for broad-spectrum drug candidates and simultaneously probes for conventional, pathogen-directed hits. With resource efficiency and pan-myxovirus activity as the central developmental parameters, we explored coscreening against two distinct, independently traceable myxoviruses in a single-well setting. Having identified a pair of unrelated pathogenic myxoviruses (influenza A virus and measles virus) with comparable replication kinetics, we observed unimpaired coreplication of both viruses, generated suitable firefly and Renilla luciferase reporter constructs, respectively, and validated the protocol for up to a 384-well plate format. Combined with an independent counterscreen using a recombinant respiratory syncytial virus luciferase reporter, implementation of the protocol identified candidates with a broadened antimyxovirus profile, in addition to pathogen-specific hits. Mechanistic characterization revealed a newly discovered broad-spectrum lead that does not block viral entry but stimulates effector pathways of the innate cellular antiviral response. In summary, we provide proof of concept for the efficient discovery of broad-spectrum myxovirus inhibitors in parallel to para- and orthomyxovirus-specific hit candidates in a single screening campaign. The newly identified compound provides a basis for the development of a novel broad-spectrum small-molecule antiviral class.
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21
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Moore TW, Sana K, Yan D, Thepchatri P, Ndungu JM, Saindane MT, Lockwood MA, Natchus MG, Liotta DC, Plemper RK, Snyder JP, Sun A. Asymmetric synthesis of host-directed inhibitors of myxoviruses. Beilstein J Org Chem 2013; 9:197-203. [PMID: 23400228 PMCID: PMC3566758 DOI: 10.3762/bjoc.9.23] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2012] [Accepted: 01/07/2013] [Indexed: 12/13/2022] Open
Abstract
High-throughput screening (HTS) previously identified benzimidazole 1 (JMN3-003) as a compound with broad antiviral activity against different influenza viruses and paramyxovirus strains. In pursuit of a lead compound from this series for development, we sought to increase both the potency and the aqueous solubility of 1. Lead optimization has achieved compounds with potent antiviral activity against a panel of myxovirus family members (EC50 values in the low nanomolar range) and much improved aqueous solubilities relative to that of 1. Additionally, we have devised a robust synthetic strategy for preparing 1 and congeners in an enantio-enriched fashion, which has allowed us to demonstrate that the (S)-enantiomers are generally 7- to 110-fold more potent than the corresponding (R)-isomers.
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Affiliation(s)
- Terry W Moore
- Emory Institute for Drug Development, Emory University, 1515 Dickey Drive, Atlanta, GA 30322, USA
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22
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Ndungu JM, Krumm SA, Yan D, Arrendale RF, Reddy GP, Evers T, Howard R, Natchus MG, Saindane MT, Liotta DC, Plemper RK, Snyder JP, Sun A. Non-nucleoside inhibitors of the measles virus RNA-dependent RNA polymerase: synthesis, structure-activity relationships, and pharmacokinetics. J Med Chem 2012; 55:4220-30. [PMID: 22480182 DOI: 10.1021/jm201699w] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
The measles virus (MeV), a member of the paramyxovirus family, is an important cause of pediatric morbidity and mortality worldwide. In an effort to provide therapeutic treatments for improved measles management, we previously identified a small, non-nucleoside organic inhibitor of the viral RNA-dependent RNA polymerase by means of high-throughput screening. Subsequent structure-activity relationship (SAR) studies around the corresponding pyrazole carboxamide scaffold led to the discovery of 2 (AS-136a), a first generation lead with low nanomolar potency against life MeV and attractive physical properties suitable for development. However, its poor water solubility and low oral bioavailability (F) in rat suggested that the lead could benefit from further SAR studies to improve the biophysical characteristics of the compound. Optimization of in vitro potency and aqueous solubility led to the discovery of 2o (ERDRP-00519), a potent inhibitor of MeV (EC(50) = 60 nM) with an aqueous solubility of approximately 60 μg/mL. The agent shows a 10-fold exposure (AUC/C(max)) increase in the rat model relative to 2, displays near dose proportionality in the range of 10-50 mg/kg, and exhibits good oral bioavailability (F = 39%). The significant solubility increase appears linked to the improved oral bioavailability.
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Affiliation(s)
- J Maina Ndungu
- Emory Institute for Drug Discovery, Emory University, 1515 Dickey Drive, Atlanta, Georgia 30322, USA
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23
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Dochow M, Krumm SA, Crowe JE, Moore ML, Plemper RK. Independent structural domains in paramyxovirus polymerase protein. J Biol Chem 2012; 287:6878-91. [PMID: 22215662 DOI: 10.1074/jbc.m111.325258] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
All enzymatic activities required for genomic replication and transcription of nonsegmented negative strand RNA viruses (or Mononegavirales) are believed to be concentrated in the viral polymerase (L) protein. However, our insight into the organization of these different enzymatic activities into a bioactive tertiary structure remains rudimentary. Fragments of Mononegavirales polymerases analyzed to date cannot restore bioactivity through trans-complementation, unlike the related L proteins of segmented NSVs. We investigated the domain organization of phylogenetically diverse Paramyxovirus L proteins derived from measles virus (MeV), Nipah virus (NiV), and respiratory syncytial virus (RSV). Through a comprehensive in silico and experimental analysis of domain intersections, we defined MeV L position 615 as an interdomain candidate in addition to the previously reported residue 1708. Only position 1708 of MeV and the homologous positions in NiV and RSV L also tolerated the insertion of epitope tags. Splitting of MeV L at residue 1708 created fragments that were unable to physically interact and trans-complement, but strikingly, these activities were reconstituted by the addition of dimerization tags to the fragments. Equivalently split fragments of NiV, RSV, and MeV L oligomerized with comparable efficiency in all homo- and heterotypic combinations, but only the homotypic pairs were able to trans-complement. These results demonstrate that synthesis as a single polypeptide is not required for the Mononegavirales polymerases to adopt a proper tertiary conformation. Paramyxovirus polymerases are composed of at least two truly independent folding domains that lack a traditional interface but require molecular compatibility for bioactivity. The functional probing of the L domain architecture through trans-complementation is anticipated to be applicable to all Mononegavirales polymerases.
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Affiliation(s)
- Melanie Dochow
- Department of Pediatrics, Emory University School of Medicine, Atlanta, Georgia 30322, USA
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24
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Sun A, Ndungu JM, Krumm SA, Yoon JJ, Thepchatri P, Natchus M, Plemper RK, Snyder JP. Host-directed Inhibitors of Myxoviruses: Synthesis and in vitro Biochemical Evaluation. ACS Med Chem Lett 2011; 2:798-803. [PMID: 22328961 DOI: 10.1021/ml200125r] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Drugs targeted to viral proteins are highly vulnerable to the development of viral resistance. One little explored approach to the treatment of viral diseases is the development of agents that target host factors required for virus replication. Myxoviruses are predominantly associated with acute disease and, thus, ideally suited for this approach since the necessary treatment time is anticipated to be limited. High-throughput screening previously identified benzimidazole 22407448 with broad anti-viral activity against different influenza virus and paramyxovirus strains. Hit to lead chemistry has generated 6p (JMN3-003) with potent antiviral activity against a panel of myxovirus family members exhibiting EC(50) values in the low nanomolar range.
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Affiliation(s)
- Aiming Sun
- Emory Institute for Drug Discovery, Emory University, Atlanta, Georgia 30322, United States
| | - J. Maina Ndungu
- Emory Institute for Drug Discovery, Emory University, Atlanta, Georgia 30322, United States
| | - Stefanie A. Krumm
- Department of Pediatrics, Emory University School of Medicine, Atlanta, Georgia 30322, United States
- Children's Healthcare of Atlanta, Atlanta, Georgia 30322, United States
| | - Jeong-Joong Yoon
- Department of Pediatrics, Emory University School of Medicine, Atlanta, Georgia 30322, United States
- Children's Healthcare of Atlanta, Atlanta, Georgia 30322, United States
| | - Pahk Thepchatri
- Emory Institute for Drug Discovery, Emory University, Atlanta, Georgia 30322, United States
| | - Michael Natchus
- Emory Institute for Drug Discovery, Emory University, Atlanta, Georgia 30322, United States
| | - Richard K. Plemper
- Department of Pediatrics, Emory University School of Medicine, Atlanta, Georgia 30322, United States
- Children's Healthcare of Atlanta, Atlanta, Georgia 30322, United States
- Department of Microbiology & Immunology, Emory University School of Medicine, Atlanta, Georgia 30322, United States
| | - James P. Snyder
- Emory Institute for Drug Discovery, Emory University, Atlanta, Georgia 30322, United States
- Department of Chemistry, Emory University, Atlanta, Georgia 30322, United States
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25
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Potent host-directed small-molecule inhibitors of myxovirus RNA-dependent RNA-polymerases. PLoS One 2011; 6:e20069. [PMID: 21603574 PMCID: PMC3095640 DOI: 10.1371/journal.pone.0020069] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2011] [Accepted: 04/15/2011] [Indexed: 12/19/2022] Open
Abstract
Therapeutic targeting of host cell factors required for virus replication rather than of pathogen components opens new perspectives to counteract virus infections. Anticipated advantages of this approach include a heightened barrier against the development of viral resistance and a broadened pathogen target spectrum. Myxoviruses are predominantly associated with acute disease and thus are particularly attractive for this approach since treatment time can be kept limited. To identify inhibitor candidates, we have analyzed hit compounds that emerged from a large-scale high-throughput screen for their ability to block replication of members of both the orthomyxovirus and paramyxovirus families. This has returned a compound class with broad anti-viral activity including potent inhibition of different influenza virus and paramyxovirus strains. After hit-to-lead chemistry, inhibitory concentrations are in the nanomolar range in the context of immortalized cell lines and human PBMCs. The compound shows high metabolic stability when exposed to human S-9 hepatocyte subcellular fractions. Antiviral activity is host-cell species specific and most pronounced in cells of higher mammalian origin, supporting a host-cell target. While the compound induces a temporary cell cycle arrest, host mRNA and protein biosynthesis are largely unaffected and treated cells maintain full metabolic activity. Viral replication is blocked at a post-entry step and resembles the inhibition profile of a known inhibitor of viral RNA-dependent RNA-polymerase (RdRp) activity. Direct assessment of RdRp activity in the presence of the reagent reveals strong inhibition both in the context of viral infection and in reporter-based minireplicon assays. In toto, we have identified a compound class with broad viral target range that blocks host factors required for viral RdRp activity. Viral adaptation attempts did not induce resistance after prolonged exposure, in contrast to rapid adaptation to a pathogen-directed inhibitor of RdRp activity.
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Measles virus infection of the CNS: human disease, animal models, and approaches to therapy. Med Microbiol Immunol 2010; 199:261-71. [PMID: 20390298 DOI: 10.1007/s00430-010-0153-2] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2010] [Indexed: 01/13/2023]
Abstract
Viral infections of the central nervous system(CNS) mostly represent clinically important, often life-threatening complications of systemic viral infections. After acute measles, CNS complications may occur early (acute postinfectious measles encephalitis, APME) or after years of viral persistence (subacute sclerosing panencephalitis, SSPE). In spite of a presumably functional cell-mediated immunity and high antiviral antibody titers, an immunological control of the CNS infection is not achieved in patients suffering from SSPE. There is still no specific therapy for acute complications and persistent MV infections of the CNS. Hamsters, rats, and (genetically unmodified and modified) mice have been used as model systems to study mechanisms of MV-induced CNS infections. Functional CD4+ and CD8+ T cells together with IFN-gamma are required to overcome the infection. With the help of recombinant measles viruses and mice expressing endogenous or transgenic receptors, interesting aspects such as receptor-dependent viral spread and viral determinants of virulence have been investigated. However, many questions concerning the lack of efficient immune control in the CNS are still open. Recent research opened new perspectives using specific antivirals such as short interfering RNA (siRNA) or small molecule inhibitors. Inspite of obvious hurdles, these treatments are the most promising approaches to future therapies.
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