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Urvashi, Senthil Kumar JB, Das P, Tandon V. Development of Azaindole-Based Frameworks as Potential Antiviral Agents and Their Future Perspectives. J Med Chem 2022; 65:6454-6495. [PMID: 35477274 PMCID: PMC9063994 DOI: 10.1021/acs.jmedchem.2c00444] [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: 03/21/2022] [Indexed: 11/29/2022]
Abstract
The azaindole (AI) framework continues to play a significant role in the design of new antiviral agents. Modulating the position and isosteric replacement of the nitrogen atom of AI analogs notably influences the intrinsic physicochemical properties of lead compounds. The intra- and intermolecular interactions of AI derivatives with host receptors or viral proteins can also be fine tuned by carefully placing the nitrogen atom in the heterocyclic core. This wide-ranging perspective article focuses on AIs that have considerable utility in drug discovery programs against RNA viruses. The inhibition of influenza A, human immunodeficiency, respiratory syncytial, neurotropic alpha, dengue, ebola, and hepatitis C viruses by AI analogs is extensively reviewed to assess their plausible future potential in antiviral drug discovery. The binding interaction of AIs with the target protein is examined to derive a structural basis for designing new antiviral agents.
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Affiliation(s)
- Urvashi
- Drug Discovery Laboratory, Special Centre for
Molecular Medicine, Jawaharlal Nehru University, New Delhi 110
067, India
- Department of Chemistry, University of
Delhi, New Delhi 110007, India
| | - J. B. Senthil Kumar
- Drug Discovery Laboratory, Special Centre for
Molecular Medicine, Jawaharlal Nehru University, New Delhi 110
067, India
| | - Parthasarathi Das
- Department of Chemistry, Indian Institute
of Technology (ISM), Dhanbad 826004, India
| | - Vibha Tandon
- Drug Discovery Laboratory, Special Centre for
Molecular Medicine, Jawaharlal Nehru University, New Delhi 110
067, India
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2
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The Synthesis and Anti-Cytomegalovirus Activity of Piperidine-4-Carboxamides. Viruses 2022; 14:v14020234. [PMID: 35215828 PMCID: PMC8876412 DOI: 10.3390/v14020234] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2021] [Revised: 01/19/2022] [Accepted: 01/21/2022] [Indexed: 01/04/2023] Open
Abstract
Treatment options for human cytomegalovirus (CMV) remain limited and are associated with significant adverse effects and the selection of resistant CMV strains in transplant recipients and congenitally infected infants. Although most approved drugs target and inhibit the CMV DNA polymerase, additional agents with distinct mechanisms of action are needed for the treatment and prevention of CMV. In a large high throughput screen using our CMV-luciferase reporter Towne, we identified several unique inhibitors of CMV replication. Here, we synthesize and test in vitro 13 analogs of the original NCGC2955 hit (1). Analogs with no activity against the CMV-luciferase at 10 µM and 30 µM (2–6, 10–14) were removed from further analysis. Three analogs (7–9) inhibited CMV replication in infected human foreskin fibroblasts. The EC50 of (1) was 1.7 ± 0.6 µM and 1.99 ± 0.15 µM, based on luciferase and plaque assay, respectively. Compounds 7, 8, and 9 showed similar activities: the EC50 values of 7 were 0.21 ± 0.06 µM (luciferase) and 0.55 ± 0.06 (plaque), of 8: 0.28 ± 0.06 µM and 0.42 ± 0.07, and of 9: 0.30 ± 0.05 µM (luciferase) and 0.35 ± 0.07 (plaque). The CC50 for 7, 8, and 9 in non-infected human foreskin fibroblasts was > 500µM, yielding a selectivity index of >1500. Compounds 1, 7, and 8 were also tested in CMV-infected primary human hepatocytes and showed a dose–response against CMV by luciferase activity and viral protein expression. None of the active compounds inhibited herpes simplex virus 1 or 2. Compounds 7 and 8 inhibited mouse CMV replication in vitro. Both inhibited CMV at late stages of replication; 7 reduced virus yield at all late time points, although not to the same degree as letermovir. Finally, the activity of analog 8 was additive with newly identified CMV inhibitors (MLS8969, NFU1827, MSL8554, and MSL8091) and with ganciclovir. Further structural activity development should provide promising anti-CMV agents for use in clinical studies.
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Replication of Equine arteritis virus is efficiently suppressed by purine and pyrimidine biosynthesis inhibitors. Sci Rep 2020; 10:10100. [PMID: 32572069 PMCID: PMC7308276 DOI: 10.1038/s41598-020-66944-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Accepted: 05/20/2020] [Indexed: 11/23/2022] Open
Abstract
RNA viruses are responsible for a large variety of animal infections. Equine Arteritis Virus (EAV) is a positive single-stranded RNA virus member of the family Arteriviridae from the order Nidovirales like the Coronaviridae. EAV causes respiratory and reproductive diseases in equids. Although two vaccines are available, the vaccination coverage of the equine population is largely insufficient to prevent new EAV outbreaks around the world. In this study, we present a high-throughput in vitro assay suitable for testing candidate antiviral molecules on equine dermal cells infected by EAV. Using this assay, we identified three molecules that impair EAV infection in equine cells: the broad-spectrum antiviral and nucleoside analog ribavirin, and two compounds previously described as inhibitors of dihydroorotate dehydrogenase (DHODH), the fourth enzyme of the pyrimidine biosynthesis pathway. These molecules effectively suppressed cytopathic effects associated to EAV infection, and strongly inhibited viral replication and production of infectious particles. Since ribavirin is already approved in human and small animal, and that several DHODH inhibitors are in advanced clinical trials, our results open new perspectives for the management of EAV outbreaks.
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Ching KC, F P Ng L, Chai CLL. A compendium of small molecule direct-acting and host-targeting inhibitors as therapies against alphaviruses. J Antimicrob Chemother 2018; 72:2973-2989. [PMID: 28981632 PMCID: PMC7110243 DOI: 10.1093/jac/dkx224] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Alphaviruses were amongst the first arboviruses to be isolated, characterized and assigned a taxonomic status. They are globally widespread, infecting a large variety of terrestrial animals, birds, insects and even fish. Moreover, they are capable of surviving and circulating in both sylvatic and urban environments, causing considerable human morbidity and mortality. The re-emergence of Chikungunya virus (CHIKV) in almost every part of the world has caused alarm to many health agencies throughout the world. The mosquito vector for this virus, Aedes, is globally distributed in tropical and temperate regions and capable of thriving in both rural and urban landscapes, giving the opportunity for CHIKV to continue expanding into new geographical regions. Despite the importance of alphaviruses as human pathogens, there is currently no targeted antiviral treatment available for alphavirus infection. This mini-review discusses some of the major features in the replication cycle of alphaviruses, highlighting the key viral targets and host components that participate in alphavirus replication and the molecular functions that were used in drug design. Together with describing the importance of these targets, we review the various direct-acting and host-targeting inhibitors, specifically small molecules that have been discovered and developed as potential therapeutics as well as their reported in vitro and in vivo efficacies.
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Affiliation(s)
- Kuan-Chieh Ching
- NUS Graduate School for Integrative Sciences and Engineering, Centre for Life Sciences, #05-01, 28 Medical Drive, Singapore 117456.,Department of Pharmacy, Faculty of Science, National University of Singapore, Block S4A, Level 3, 18 Science Drive 4, Singapore 117543
| | - Lisa F P Ng
- Singapore Immunology Network, A*STAR, 8A Biomedical Grove, Immunos Building, #04-06, Singapore 138648.,Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Block MD6, Centre for Translational Medicine, 14 Medical Drive, #14-01T, Singapore 117599.,Institute of Infection and Global Health, University of Liverpool, Ronald Ross Building, 8 West Derby Street, Liverpool L697BE, UK
| | - Christina L L Chai
- NUS Graduate School for Integrative Sciences and Engineering, Centre for Life Sciences, #05-01, 28 Medical Drive, Singapore 117456.,Department of Pharmacy, Faculty of Science, National University of Singapore, Block S4A, Level 3, 18 Science Drive 4, Singapore 117543
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5
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Cappariloside A shows antiviral and better anti-inflammatory effects against influenza virus via regulating host IFN signaling, in vitro and vivo. Life Sci 2018; 200:115-125. [DOI: 10.1016/j.lfs.2018.03.033] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2017] [Revised: 03/14/2018] [Accepted: 03/15/2018] [Indexed: 11/22/2022]
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Blakely PK, Huber AK, Irani DN. Type-1 angiotensin receptor signaling in central nervous system myeloid cells is pathogenic during fatal alphavirus encephalitis in mice. J Neuroinflammation 2016; 13:196. [PMID: 27562117 PMCID: PMC5000512 DOI: 10.1186/s12974-016-0683-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2016] [Accepted: 08/18/2016] [Indexed: 01/19/2023] Open
Abstract
BACKGROUND Alphaviruses can cause fatal encephalitis in humans. Natural infections occur via the bite of infected mosquitos, but aerosol transmissibility makes some of these viruses potential bioterrorism agents. Central nervous system (CNS) host responses contribute to alphavirus pathogenesis in experimental models and are logical therapeutic targets. We investigated whether reactive oxygen species (ROS) generated by nicotinamide adenine dinucleotide phosphate (NADPH) oxidase (Nox) activity within the CNS contributes to fatal alphavirus encephalitis in mice. METHODS Infected animals were treated systemically with the angiotensin receptor-blocking drug, telmisartan, given its ability to cross the blood-brain barrier, selectively block type-1 angiotensin receptors (AT1R), and inhibit Nox-derived ROS production in vascular smooth muscle and other extraneural tissues. Clinical, virological, biochemical, and histopathological outcomes were followed over time. RESULTS The importance of the angiotensin II (Ang II)/AT1R axis in disease pathogenesis was confirmed by demonstrating increased Ang II levels in the CNS following infection, enhanced disease survival when CNS Ang II production was suppressed, increased AT1R expression on microglia and tissue-infiltrating myeloid cells, and enhanced disease survival in AT1R-deficient mice compared to wild-type (WT) controls. Systemic administration of telmisartan protected WT mice from lethal encephalitis caused by two different alphaviruses in a dose-dependent manner without altering virus replication or exerting any anti-inflammatory effects in the CNS. Infection triggered up-regulation of multiple Nox subunits in the CNS, while drug treatment inhibited local Nox activity, ROS production, and oxidative neuronal damage. Telmisartan proved ineffective in Nox-deficient mice, demonstrating that this enzyme is its main target in this experimental setting. CONCLUSIONS Nox-derived ROS, likely arising from CNS myeloid cells triggered by AT1R signaling, are pathogenic during fatal alphavirus encephalitis in mice. Systemically administered telmisartan at non-hypotensive doses targets Nox activity in the CNS to exert a neuroprotective effect. Disruption of this pathway may have broader implications for the treatment of related infections as well as for other CNS diseases driven by oxidative injury.
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Affiliation(s)
- Pennelope K Blakely
- Holtom-Garrett Program in Neuroimmunology, Department of Neurology, University of Michigan Medical School, Room 4007, A. Alfred Taubman Biomedical Sciences Research Building, 109 Zina Pitcher Place, Ann Arbor, MI, 48109-2200, USA
| | - Amanda K Huber
- Holtom-Garrett Program in Neuroimmunology, Department of Neurology, University of Michigan Medical School, Room 4007, A. Alfred Taubman Biomedical Sciences Research Building, 109 Zina Pitcher Place, Ann Arbor, MI, 48109-2200, USA
| | - David N Irani
- Holtom-Garrett Program in Neuroimmunology, Department of Neurology, University of Michigan Medical School, Room 4007, A. Alfred Taubman Biomedical Sciences Research Building, 109 Zina Pitcher Place, Ann Arbor, MI, 48109-2200, USA.
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Ching KC, Kam YW, Merits A, Ng LFP, Chai CLL. Trisubstituted Thieno[3,2-b]pyrrole 5-Carboxamides as Potent Inhibitors of Alphaviruses. J Med Chem 2015; 58:9196-213. [DOI: 10.1021/acs.jmedchem.5b01047] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Affiliation(s)
- Kuan-Chieh Ching
- NUS Graduate School for Integrative Sciences and Engineering, Centre for Life Sciences, #05-01, 28 Medical Drive, Singapore 117456
- Department
of Pharmacy, Faculty of Science, National University of Singapore, Block S4A, Level 3, 18 Science Drive 4, Singapore 117543
| | - Yiu-Wing Kam
- Singapore
Immunology Network, A*STAR, 8A Biomedical Grove, Immunos Building,
Level 4, Singapore 138648
| | - Andres Merits
- Institute
of Technology, University of Tartu, Nooruse 1, Tartu, Estonia 50411
| | - Lisa F. P. Ng
- Singapore
Immunology Network, A*STAR, 8A Biomedical Grove, Immunos Building,
Level 4, Singapore 138648
- Department
of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Block MD6, Centre for Translational Medicine, 14 Medical Drive, #14-01T, Singapore 117599
| | - Christina L. L. Chai
- NUS Graduate School for Integrative Sciences and Engineering, Centre for Life Sciences, #05-01, 28 Medical Drive, Singapore 117456
- Department
of Pharmacy, Faculty of Science, National University of Singapore, Block S4A, Level 3, 18 Science Drive 4, Singapore 117543
- Institute
of Chemical and Engineering Sciences, A*STAR, 8 Biomedical Grove, Neuros Building,
#07-01/02/03, Singapore 138665
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Xu J, Sharma N, Sharma UK, Li Z, Song G, Van der Eycken EV. Cationic Rhodium(III)-Catalyzed Direct C-2 Carboxamidation of Indoles with IsocyanatesviaCH Bond Functionalization. Adv Synth Catal 2015. [DOI: 10.1002/adsc.201500109] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
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9
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Barraza SJ, Delekta PC, Sindac JA, Dobry CJ, Xiang J, Keep RF, Miller DJ, Larsen SD. Discovery of anthranilamides as a novel class of inhibitors of neurotropic alphavirus replication. Bioorg Med Chem 2015; 23:1569-87. [PMID: 25740634 DOI: 10.1016/j.bmc.2015.01.054] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2014] [Revised: 01/22/2015] [Accepted: 01/30/2015] [Indexed: 01/16/2023]
Abstract
Neurotropic alphaviruses are debilitating pathogens that infect the central nervous system (CNS) and are transmitted to humans via mosquitoes. There exist no effective human vaccines against these viruses, underlining the need for effective antivirals, but no antiviral drugs are available for treating infection once the viruses have invaded the CNS. Previously, we reported the development of novel indole-2-carboxamide-based inhibitors of alphavirus replication that demonstrate significant reduction of viral titer and achieve measurable brain permeation in a pharmacokinetic mouse model. Herein we report our continued efforts to improve physicochemical properties predictive of in vivo blood-brain barrier (BBB) permeability through reduction of overall molecular weight, replacing the indole core with a variety of aromatic and non-aromatic monocyclics. These studies culminated in the identification of simple anthranilamides that retain excellent potency with improved metabolic stability and significantly greater aqueous solubility. Furthermore, in a live virus study, we showed that two new compounds were capable of reducing viral titer by two orders of magnitude and that these compounds likely exert their effects through a mechanism similar to that of our indole-2-carboxamide inhibitors.
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Affiliation(s)
- Scott J Barraza
- Department of Medicinal Chemistry, College of Pharmacy, University of Michigan, Ann Arbor, MI 48109, United States
| | - Philip C Delekta
- Department of Internal Medicine, University of Michigan, Ann Arbor, MI 48109, United States
| | - Janice A Sindac
- Department of Medicinal Chemistry, College of Pharmacy, University of Michigan, Ann Arbor, MI 48109, United States
| | - Craig J Dobry
- Department of Internal Medicine, University of Michigan, Ann Arbor, MI 48109, United States
| | - Jianming Xiang
- Department of Neurosurgery, University of Michigan, Ann Arbor, MI 48109, United States
| | - Richard F Keep
- Department of Neurosurgery, University of Michigan, Ann Arbor, MI 48109, United States
| | - David J Miller
- Department of Internal Medicine, University of Michigan, Ann Arbor, MI 48109, United States; Department of Microbiology and Immunology, University of Michigan, Ann Arbor, MI 48109, United States.
| | - Scott D Larsen
- Department of Medicinal Chemistry, College of Pharmacy, University of Michigan, Ann Arbor, MI 48109, United States; Vahlteich Medicinal Chemistry Core, College of Pharmacy, University of Michigan, Ann Arbor, MI 48109, United States.
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10
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Delekta PC, Raveh A, Larsen MJ, Schultz PJ, Tamayo-Castillo G, Sherman DH, Miller DJ. The combined use of alphavirus replicons and pseudoinfectious particles for the discovery of antivirals derived from natural products. ACTA ACUST UNITED AC 2014; 20:673-80. [PMID: 25550354 DOI: 10.1177/1087057114564868] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2014] [Accepted: 11/28/2014] [Indexed: 11/15/2022]
Abstract
Alphaviruses are a prominent class of reemergent pathogens due to their globally expanding ranges, potential for lethality, and possible use as bioweapons. The absence of effective treatments for alphaviruses highlights the need for innovative strategies to identify antiviral agents. Primary screens that use noninfectious self-replicating RNAs, termed replicons, have been used to identify potential antiviral compounds for alphaviruses. Only inhibitors of viral genome replication, however, will be identified using replicons, which excludes many other druggable steps in the viral life cycle. To address this limitation, we developed a western equine encephalitis virus pseudoinfectious particle system that reproduces several crucial viral life cycle steps in addition to genome replication. We used this system to screen a library containing ~26,000 extracts derived from marine microbes, and we identified multiple bacterial strains that produce compounds with potential antiviral activity. We subsequently used pseudoinfectious particle and replicon assays in parallel to counterscreen candidate extracts, and followed antiviral activity during biochemical fractionation and purification to differentiate between inhibitors of viral entry and genome replication. This novel process led to the isolation of a known alphavirus entry inhibitor, bafilomycin, thereby validating the approach for the screening and identification of potential antiviral compounds.
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Affiliation(s)
- Phillip C Delekta
- Department of Internal Medicine, University of Michigan, Ann Arbor, MI, USA
| | - Avi Raveh
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA
| | - Martha J Larsen
- Center for Chemical Genomics, University of Michigan, Ann Arbor, MI, USA
| | - Pamela J Schultz
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA
| | | | - David H Sherman
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, MI, USA Department of Chemistry and Medicinal Chemistry, University of Michigan, Ann Arbor, MI, USA Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA
| | - David J Miller
- Department of Internal Medicine, University of Michigan, Ann Arbor, MI, USA Department of Microbiology and Immunology, University of Michigan, Ann Arbor, MI, USA
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Blakely PK, Delekta PC, Miller DJ, Irani DN. Manipulation of host factors optimizes the pathogenesis of western equine encephalitis virus infections in mice for antiviral drug development. J Neurovirol 2014; 21:43-55. [PMID: 25361697 DOI: 10.1007/s13365-014-0297-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2014] [Revised: 09/18/2014] [Accepted: 09/24/2014] [Indexed: 11/25/2022]
Abstract
While alphaviruses spread naturally via mosquito vectors, some can also be transmitted as aerosols making them potential bioterrorism agents. One such pathogen, western equine encephalitis virus (WEEV), causes fatal human encephalitis via multiple routes of infection and thus presumably via multiple mechanisms. Although WEEV also produces acute encephalitis in non-human primates, a small animal model that recapitulates features of human disease would be useful for both pathogenesis studies and to evaluate candidate antiviral therapies. We have optimized conditions to infect mice with a low passage isolate of WEEV, thereby allowing detailed investigation of virus tropism, replication, neuroinvasion, and neurovirulence. We find that host factors strongly influence disease outcome, and in particular, that age, gender, and genetic background all have significant effects on disease susceptibility independent of virus tropism or replication within the central nervous system. Our data show that experimental variables can be adjusted in mice to recapitulate disease features known to occur in both non-human primates and humans, thus aiding further study of WEEV pathogenesis and providing a realistic therapeutic window for antiviral drug delivery.
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MESH Headings
- Administration, Intranasal
- Alphavirus Infections/pathology
- Alphavirus Infections/virology
- Animals
- Behavior, Animal
- Cognition
- Disease Models, Animal
- Encephalitis Virus, Western Equine/pathogenicity
- Encephalitis Virus, Western Equine/physiology
- Host Specificity
- Injections, Intraperitoneal
- Injections, Subcutaneous
- Mice
- Mice, Inbred BALB C
- Mice, Inbred C57BL
- Mice, Inbred DBA
- RNA, Viral/blood
- Seizures/pathology
- Seizures/virology
- Species Specificity
- Viral Load
- Virus Replication
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Affiliation(s)
- Pennelope K Blakely
- Department of Neurology, University of Michigan Medical School, 4007 Biomedical Sciences Research Building, 109 Zina Pitcher Place, Ann Arbor, MI, 48109-2200, USA
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