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Brun P, Qesari M, Marconi PC, Kotsafti A, Porzionato A, Macchi V, Schwendener RA, Scarpa M, Giron MC, Palù G, Calistri A, Castagliuolo I. Herpes Simplex Virus Type 1 Infects Enteric Neurons and Triggers Gut Dysfunction via Macrophage Recruitment. Front Cell Infect Microbiol 2018; 8:74. [PMID: 29600197 PMCID: PMC5862801 DOI: 10.3389/fcimb.2018.00074] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2017] [Accepted: 02/27/2018] [Indexed: 12/27/2022] Open
Abstract
Herpes Simplex Virus type 1 (HSV-1), a neurotropic pathogen widespread in human population, infects the enteric nervous system (ENS) in humans and rodents and causes intestinal neuromuscular dysfunction in rats. Although infiltration of inflammatory cells in the myenteric plexus and neurodegeneration of enteric nerves are common features of patients suffering from functional intestinal disorders, the proof of a pathogenic link with HSV-1 is still unsettled mainly because the underlying mechanisms are largely unknown. In this study we demonstrated that following intragastrical administration HSV-1 infects neurons within the myenteric plexus resulting in functional and structural alterations of the ENS. By infecting mice with HSV-1 replication-defective strain we revealed that gastrointestinal neuromuscular anomalies were however independent of viral replication. Indeed, enteric neurons exposed to UV-inactivated HSV-1 produced monocyte chemoattractant protein-1 (MCP-1/CCL2) to recruit activated macrophages in the longitudinal muscle myenteric plexus. Infiltrating macrophages produced reactive oxygen and nitrogen species and directly harmed enteric neurons resulting in gastrointestinal dysmotility. In HSV-1 infected mice intestinal neuromuscular dysfunctions were ameliorated by in vivo administration of (i) liposomes containing dichloromethylene bisphosphonic acid (clodronate) to deplete tissue macrophages, (ii) CCR2 chemokine receptor antagonist RS504393 to block the CCL2/CCR2 pathway, (iii) Nω-Nitro-L-arginine methyl ester hydrochloride (L-NAME) and AR-C 102222 to quench production of nitrogen reactive species produced via iNOS. Overall these data demonstrate that HSV-1 infection makes enteric neurons recruit macrophages via production of a specific chemoattractant factor. The resulting inflammatory reaction is mandatory for intestinal dysmotility. These findings provide insights into the neuro-immune communication that occurs in the ENS following HSV-1 infection and allow recognition of an original pathophysiologic mechanism underlying gastrointestinal diseases as well as identification of novel therapeutic targets.
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Affiliation(s)
- Paola Brun
- Department of Molecular Medicine, University of Padova, Padova, Italy
| | - Marsela Qesari
- Department of Pharmaceutical and Pharmacological Sciences, University of Padova, Padova, Italy
| | - Peggy C Marconi
- Department of Life Sciences and Biotechnology, University of Ferrara, Ferrara, Italy
| | - Andromachi Kotsafti
- Esophageal and Digestive Tract Surgery Unit, Veneto Institute of Oncology IOV-IRCCS, Padova, Italy
| | | | - Veronica Macchi
- Department of Neurosciences, University of Padova, Padova, Italy
| | - Reto A Schwendener
- Institute of Molecular Cancer Research, University of Zurich, Zurich, Switzerland
| | - Marco Scarpa
- Esophageal and Digestive Tract Surgery Unit, Veneto Institute of Oncology IOV-IRCCS, Padova, Italy
| | - Maria C Giron
- Department of Pharmaceutical and Pharmacological Sciences, University of Padova, Padova, Italy
| | - Giorgio Palù
- Department of Molecular Medicine, University of Padova, Padova, Italy
| | - Arianna Calistri
- Department of Molecular Medicine, University of Padova, Padova, Italy
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Kim JA, Seong RK, Kumar M, Shin OS. Favipiravir and Ribavirin Inhibit Replication of Asian and African Strains of Zika Virus in Different Cell Models. Viruses 2018; 10:v10020072. [PMID: 29425176 PMCID: PMC5850379 DOI: 10.3390/v10020072] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2018] [Revised: 01/29/2018] [Accepted: 02/08/2018] [Indexed: 11/16/2022] Open
Abstract
Zika virus (ZIKV) has recently emerged as a new public health threat. ZIKV infections have caused a wide spectrum of neurological diseases, such as Guillain-Barré syndrome, myelitis, meningoencephalitis, and congenital microcephaly. No effective therapies currently exist for treating patients infected with ZIKV. Herein, we evaluated the anti-viral activity of favipiravir (T-705) and ribavirin against Asian and African strains of ZIKV using different cell models, including human neuronal progenitor cells (hNPCs), human dermal fibroblasts (HDFs), human lung adenocarcinoma cells (A549) and Vero cells. Cells were treated with favipiravir or ribavirin and effects on ZIKV replication were determined using quantitative real-time PCR and plaque assay. Our results demonstrate that favipiravir or ribavirin treatment significantly inhibited ZIKV replication in a dose-dependent manner. Moreover, favipiravir treatment of ZIKV-infected hNPCs led to reduced cell death, enhanced AKT pathway phosphorylation, and increased expression of anti-apoptotic factor B cell lymphoma 2. In conclusion, our results demonstrate conclusively that favipiravir inhibits ZIKV replication and prevents cell death, and can be a promising intervention for ZIKV-associated disease.
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Affiliation(s)
- Ji-Ae Kim
- Department of Biomedical Sciences, College of Medicine, Korea University Guro Hospital, Seoul 08308, Korea.
| | - Rak-Kyun Seong
- Department of Biomedical Sciences, College of Medicine, Korea University Guro Hospital, Seoul 08308, Korea.
| | - Mukesh Kumar
- Department of Tropical Medicine, Medical Microbiology and Pharmacology, Pacific Center for Emerging Infectious Diseases Research, John A. Burns School of Medicine, University of Hawaii at Manoa, Honolulu, HI 96813, USA.
| | - Ok Sarah Shin
- Department of Biomedical Sciences, College of Medicine, Korea University Guro Hospital, Seoul 08308, Korea.
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Zika Virus Infects Human Sertoli Cells and Modulates the Integrity of the In Vitro Blood-Testis Barrier Model. J Virol 2017; 91:JVI.00623-17. [PMID: 28878076 DOI: 10.1128/jvi.00623-17] [Citation(s) in RCA: 93] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2017] [Accepted: 08/23/2017] [Indexed: 12/20/2022] Open
Abstract
Confirmed reports of Zika virus (ZIKV) in human seminal fluid for months after the clearance of viremia suggest the ability of ZIKV to establish persistent infection in the seminiferous tubules, an immune-privileged site in the testis protected by the blood-testis barrier, also called the Sertoli cell (SC) barrier (SCB). However, cellular targets of ZIKV in human testis and mechanisms by which the virus enters seminiferous tubules remain unclear. We demonstrate that primary human SCs were highly susceptible to ZIKV compared to the closely related dengue virus and induced the expression of alpha interferon (IFN-α), key cytokines, and cell adhesion molecules (vascular cell adhesion molecule 1 [VCAM-1] and intracellular adhesion molecule 1 [ICAM-1]). Furthermore, using an in vitro SCB model, we show that ZIKV was released on the adluminal side of the SCB model with a higher efficiency than in the blood-brain barrier model. ZIKV-infected SCs exhibited enhanced adhesion of leukocytes that correlated with decreases in SCB integrity. ZIKV infection did not affect the expression of tight and adherens junction proteins such as ZO-1, claudin, and JAM-A; however, exposure of SCs to inflammatory mediators derived from ZIKV-infected macrophages led to the degradation of the ZO-1 protein, which correlated with increased SCB permeability. Taken together, our data suggest that infection of SCs may be one of the crucial steps by which ZIKV gains access to the site of spermatozoon development and identify SCs as a therapeutic target to clear testicular infections. The SCB model opens up opportunities to assess interactions of SCs with other testicular cells and to test the ability of anti-ZIKV drugs to cross the barrier.IMPORTANCE Recent outbreaks of ZIKV, a neglected mosquito-borne flavivirus, have identified sexual transmission as a new route of disease spread, which has not been reported for other flaviviruses. To be able to sexually transmit for months after the clearance of viremia, ZIKV must establish infection in the seminiferous tubules, the site of spermatozoon development. However, little is known about the cell types that support ZIKV infection in the human testis. Currently, there are no models to study mechanisms of virus persistence in the seminiferous tubules. We provide evidence that ZIKV infection of human Sertoli cells, which are an important component of the seminiferous tubules, is robust and induces a strong antiviral response. The use of an in vitro Sertoli cell barrier to describe how ZIKV or inflammatory mediators derived from ZIKV-infected macrophages compromise barrier integrity will enable studies to explore the interactions of other testicular cells with Sertoli cells and to test novel antivirals for clearing testicular ZIKV infection.
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Olmo IG, Carvalho TG, Costa VV, Alves-Silva J, Ferrari CZ, Izidoro-Toledo TC, da Silva JF, Teixeira AL, Souza DG, Marques JT, Teixeira MM, Vieira LB, Ribeiro FM. Zika Virus Promotes Neuronal Cell Death in a Non-Cell Autonomous Manner by Triggering the Release of Neurotoxic Factors. Front Immunol 2017; 8:1016. [PMID: 28878777 PMCID: PMC5572413 DOI: 10.3389/fimmu.2017.01016] [Citation(s) in RCA: 60] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2017] [Accepted: 08/08/2017] [Indexed: 11/13/2022] Open
Abstract
Zika virus (ZIKV) has recently caused a worldwide outbreak of infections associated with severe neurological complications, including microcephaly in infants born from infected mothers. ZIKV exhibits high neurotropism and promotes neuroinflammation and neuronal cell death. We have recently demonstrated that N-methyl-d-aspartate receptor (NMDAR) blockade by memantine prevents ZIKV-induced neuronal cell death. Here, we show that ZIKV induces apoptosis in a non-cell autonomous manner, triggering cell death of uninfected neurons by releasing cytotoxic factors. Neuronal cultures infected with ZIKV exhibit increased levels of tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and glutamate. Moreover, infected neurons exhibit increased expression of GluN2B and augmented intracellular Ca2+ concentration. Blockade of GluN2B-containing NMDAR by ifenprodil normalizes Ca2+ levels and rescues neuronal cell death. Notably, TNF-α and IL-1β blockade decreases ZIKV-induced Ca2+ flux through GluN2B-containing NMDARs and reduces neuronal cell death, indicating that these cytokines might contribute to NMDAR sensitization and neurotoxicity. In addition, ZIKV-infected cultures treated with ifenprodil exhibits increased activation of the neuroprotective pathway including extracellular signal-regulated kinase and cAMP response element-binding protein, which may underlie ifenprodil-mediated neuroprotection. Together, our data shed some light on the neurotoxic mechanisms triggered by ZIKV and begin to elucidate how GluN2B-containing NMDAR blockade can prevent neurotoxicity.
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Affiliation(s)
- Isabella G Olmo
- Department of Biochemistry and Immunology, Institute of Biological Sciences (ICB), Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, Brazil
| | - Toniana G Carvalho
- Department of Biochemistry and Immunology, Institute of Biological Sciences (ICB), Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, Brazil
| | - Vivian V Costa
- Department of Biochemistry and Immunology, Institute of Biological Sciences (ICB), Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, Brazil
| | - Juliana Alves-Silva
- Department of Biochemistry and Immunology, Institute of Biological Sciences (ICB), Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, Brazil
| | | | - Tatiane C Izidoro-Toledo
- Department of Biochemistry and Immunology, Institute of Biological Sciences (ICB), Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, Brazil
| | | | - Antonio L Teixeira
- Neuropsychiatry Program, Department of Psychiatry and Behavioral Science, UT Health, Houston, TX, United States
| | | | - Joao T Marques
- Department of Biochemistry and Immunology, Institute of Biological Sciences (ICB), Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, Brazil
| | - Mauro M Teixeira
- Department of Biochemistry and Immunology, Institute of Biological Sciences (ICB), Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, Brazil
| | | | - Fabiola M Ribeiro
- Department of Biochemistry and Immunology, Institute of Biological Sciences (ICB), Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, Brazil
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Palus M, Vancova M, Sirmarova J, Elsterova J, Perner J, Ruzek D. Tick-borne encephalitis virus infects human brain microvascular endothelial cells without compromising blood-brain barrier integrity. Virology 2017; 507:110-122. [DOI: 10.1016/j.virol.2017.04.012] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2017] [Revised: 04/13/2017] [Accepted: 04/14/2017] [Indexed: 12/11/2022]
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Newhouse DJ, Hofmeister EK, Balakrishnan CN. Transcriptional response to West Nile virus infection in the zebra finch ( Taeniopygia guttata). ROYAL SOCIETY OPEN SCIENCE 2017; 4:170296. [PMID: 28680683 PMCID: PMC5493925 DOI: 10.1098/rsos.170296] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2017] [Accepted: 05/22/2017] [Indexed: 05/04/2023]
Abstract
West Nile virus (WNV) is a widespread arbovirus that imposes a significant cost to both human and wildlife health. WNV exists in a bird-mosquito transmission cycle in which passerine birds act as the primary reservoir host. As a public health concern, the mammalian immune response to WNV has been studied in detail. Little, however, is known about the avian immune response to WNV. Avian taxa show variable susceptibility to WNV and what drives this variation is unknown. Thus, to study the immune response to WNV in birds, we experimentally infected captive zebra finches (Taeniopygia guttata). Zebra finches provide a useful model, as like many natural avian hosts they are moderately susceptible to WNV and thus provide sufficient viremia to infect mosquitoes. We performed RNAseq in spleen tissue during peak viremia to provide an overview of the transcriptional response. In general, we find strong parallels with the mammalian immune response to WNV, including upregulation of five genes in the Rig-I-like receptor signalling pathway, and offer insights into avian-specific responses. Together with complementary immunological assays, we provide a model of the avian immune response to WNV and set the stage for future comparative studies among variably susceptible populations and species.
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Affiliation(s)
- Daniel J. Newhouse
- Department of Biology, East Carolina University, Greenville, NC 27858, USA
- Author for correspondence: Daniel J. Newhouse e-mail:
| | - Erik K. Hofmeister
- US Geological Survey, National Wildlife Health Center, 6006 Schroeder Road, Madison, WI 53711, USA
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Salimi H, Cain MD, Klein RS. Encephalitic Arboviruses: Emergence, Clinical Presentation, and Neuropathogenesis. Neurotherapeutics 2016; 13:514-34. [PMID: 27220616 PMCID: PMC4965410 DOI: 10.1007/s13311-016-0443-5] [Citation(s) in RCA: 65] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Arboviruses are arthropod-borne viruses that exhibit worldwide distribution, contributing to systemic and neurologic infections in a variety of geographical locations. Arboviruses are transmitted to vertebral hosts during blood feedings by mosquitoes, ticks, biting flies, mites, and nits. While the majority of arboviral infections do not lead to neuroinvasive forms of disease, they are among the most severe infectious risks to the health of the human central nervous system. The neurologic diseases caused by arboviruses include meningitis, encephalitis, myelitis, encephalomyelitis, neuritis, and myositis in which virus- and immune-mediated injury may lead to severe, persisting neurologic deficits or death. Here we will review the major families of emerging arboviruses that cause neurologic infections, their neuropathogenesis and host neuroimmunologic responses, and current strategies for treatment and prevention of neurologic infections they cause.
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Affiliation(s)
- Hamid Salimi
- Department of Internal Medicine, Washington University School of Medicine, St. Louis, MO, USA
| | - Matthew D Cain
- Department of Internal Medicine, Washington University School of Medicine, St. Louis, MO, USA
| | - Robyn S Klein
- Department of Internal Medicine, Washington University School of Medicine, St. Louis, MO, USA.
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO, USA.
- Department of Neuroscience, Washington University School of Medicine, St. Louis, MO, USA.
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Identification of host genes leading to West Nile virus encephalitis in mice brain using RNA-seq analysis. Sci Rep 2016; 6:26350. [PMID: 27211830 PMCID: PMC4876452 DOI: 10.1038/srep26350] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2016] [Accepted: 04/26/2016] [Indexed: 01/23/2023] Open
Abstract
Differential host responses may be critical determinants of distinct pathologies of West Nile virus (WNV) NY99 (pathogenic) and WNV Eg101 (non-pathogenic) strains. We employed RNA-seq technology to analyze global differential gene expression in WNV-infected mice brain and to identify the host cellular factors leading to lethal encephalitis. We identified 1,400 and 278 transcripts, which were differentially expressed after WNV NY99 and WNV Eg101 infections, respectively, and 147 genes were common to infection with both the viruses. Genes that were up-regulated in infection with both the viruses were mainly associated with interferon signaling. Genes associated with inflammation and cell death/apoptosis were only expressed after WNV NY99 infection. We demonstrate that differences in the activation of key pattern recognition receptors resulted in the induction of unique innate immune profiles, which corresponded with the induction of interferon and inflammatory responses. Pathway analysis of differentially expressed genes indicated that after WNV NY99 infection, TREM-1 mediated activation of toll-like receptors leads to the high inflammatory response. In conclusion, we have identified both common and specific responses to WNV NY99 and WNV Eg101 infections as well as genes linked to potential resistance to infection that may be targets for therapeutics.
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Innate and adaptive immune responses to tick-borne flavivirus infection in sheep. Vet Microbiol 2016; 185:20-8. [PMID: 26931387 DOI: 10.1016/j.vetmic.2016.01.015] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2015] [Revised: 01/08/2016] [Accepted: 01/20/2016] [Indexed: 02/07/2023]
Abstract
The flaviviruses tick-borne encephalitis virus (TBEV) and louping ill virus (LIV) are closely-related genetically and antigenically, have broadly similar host ranges that include rodents and other mammals (including sheep), and are both transmitted by the same tick species, Ixodes ricinus. Although human infection with TBEV results in a febrile illness followed in some cases by encephalitis, humans appear to be much less susceptible to infection with LIV. However, these viruses demonstrate different susceptibilities in sheep; LIV infection causes encephalitic disease, whereas TBEV infection generally does not. To investigate the role of the immune response in this mixed outcome, groups of sheep were inoculated with either virus, or with a primary inoculation with one virus and secondary inoculation with the other. Markers of both adaptive and innate immune responses were measured. In each group studied, infection resulted in seroconversion, demonstrated by the detection of virus specific neutralising antibodies. This appeared to control infection with TBEV but not LIV, which progressed to a febrile infection, with transient viraemia and elevated levels of serum interferon. This was followed by neuroinvasion, leading to up-regulation of innate immune transcripts in discrete areas of the brain, including interferon inducible genes and chemokines. Prior inoculation with TBEV did not prevent infection with LIV, but did appear to reduce disease severity and viraemia. We postulate that LIV has adapted to replicate efficiently in sheep cells, and disseminate rapidly following infection. By contrast, TBEV fails to disseminate in sheep and is controlled by the immune response.
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Kuwar R, Stokic D, Leis A, Bai F, Paul A, Fratkin J, Vig P. Does astroglial protein S100B contribute to West Nile neuro-invasive syndrome? J Neurol Sci 2015; 358:243-52. [DOI: 10.1016/j.jns.2015.09.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2015] [Revised: 09/02/2015] [Accepted: 09/02/2015] [Indexed: 12/18/2022]
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Kumar M, Roe K, O'Connell M, Nerurkar VR. Induction of virus-specific effector immune cell response limits virus replication and severe disease in mice infected with non-lethal West Nile virus Eg101 strain. J Neuroinflammation 2015; 12:178. [PMID: 26392176 PMCID: PMC4578235 DOI: 10.1186/s12974-015-0400-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2015] [Accepted: 09/11/2015] [Indexed: 01/11/2023] Open
Abstract
Background West Nile virus (WNV) is a neurotropic flavivirus that has emerged globally as a significant cause of viral encephalitis in humans. Herein, we investigated the immunological responses induced by two phylogenetically related WNV strains of lineage 1, WNV NY99, and WNV Eg101. Methods Eight-week-old C57BL/6J mice were inoculated with WNV NY99 or WNV Eg101 and mortality, virus burden in the periphery and brain, type 1 interferon response, WNV-specific antibodies, leukocyte infiltration, and inflammatory responses were analyzed. Results As expected, WNV NY99 infected mice demonstrated high morbidity and mortality, whereas no morbidity and mortality was observed in WNV Eg101 infected mice. Virus titers were comparable in the serum of both WNV NY99 and WNV Eg101 infected mice at day 3 after inoculation; however, at day 6, the virus was cleared from WNV Eg101 infected mice but the virus titer remained high in the WNV NY99 infected mice. Virus was detected in the brains of both WNV NY99 and Eg101 infected mice, albeit significantly higher in the brains of WNV NY99 infected mice. Surprisingly, levels of type 1 interferon and WNV-specific antibodies were significantly higher in the serum and brains of WNV NY99 infected mice. Similarly, protein levels of multiple cytokines and chemokines were significantly higher in the serum and brains of WNV NY99 infected mice. In contrast, we observed significantly higher numbers of innate and adaptive immune cells in the spleens and brains of WNV Eg101 infected mice. Moreover, total number and percentage of IFN-γ and TNF-α producing WNV-specific CD8+ T cells were also significantly high in WNV Eg101 infected mice. Conclusions Our data demonstrate that induction of virus-specific effector immune cell response limits virus replication and severe WNV disease in Eg101 infected mice. Our data also demonstrate an inverse correlation between leukocyte accumulation and production of pro-inflammatory mediators in WNV-infected mice. Moreover, increased production of pro-inflammatory mediators was associated with high-virus titers and increased mortality in WNV NY99 infected mice.
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Affiliation(s)
- Mukesh Kumar
- Department of Tropical Medicine, Medical Microbiology and Pharmacology, John A. Burns School of Medicine, University of Hawaii at Manoa, 651 Ilalo Street, Honolulu, 96813, Hawaii, USA. .,Pacific Center for Emerging Infectious Diseases Research, John A. Burns School of Medicine, University of Hawaii at Manoa, 651 Ilalo Street, Honolulu, Hawaii, 96813, USA.
| | - Kelsey Roe
- Department of Tropical Medicine, Medical Microbiology and Pharmacology, John A. Burns School of Medicine, University of Hawaii at Manoa, 651 Ilalo Street, Honolulu, 96813, Hawaii, USA. .,Pacific Center for Emerging Infectious Diseases Research, John A. Burns School of Medicine, University of Hawaii at Manoa, 651 Ilalo Street, Honolulu, Hawaii, 96813, USA.
| | - Maile O'Connell
- Department of Tropical Medicine, Medical Microbiology and Pharmacology, John A. Burns School of Medicine, University of Hawaii at Manoa, 651 Ilalo Street, Honolulu, 96813, Hawaii, USA. .,Pacific Center for Emerging Infectious Diseases Research, John A. Burns School of Medicine, University of Hawaii at Manoa, 651 Ilalo Street, Honolulu, Hawaii, 96813, USA.
| | - Vivek R Nerurkar
- Department of Tropical Medicine, Medical Microbiology and Pharmacology, John A. Burns School of Medicine, University of Hawaii at Manoa, 651 Ilalo Street, Honolulu, 96813, Hawaii, USA. .,Pacific Center for Emerging Infectious Diseases Research, John A. Burns School of Medicine, University of Hawaii at Manoa, 651 Ilalo Street, Honolulu, Hawaii, 96813, USA.
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Francisco NM, Hsu NJ, Keeton R, Randall P, Sebesho B, Allie N, Govender D, Quesniaux V, Ryffel B, Kellaway L, Jacobs M. TNF-dependent regulation and activation of innate immune cells are essential for host protection against cerebral tuberculosis. J Neuroinflammation 2015; 12:125. [PMID: 26112704 PMCID: PMC4488051 DOI: 10.1186/s12974-015-0345-1] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2015] [Accepted: 06/16/2015] [Indexed: 11/10/2022] Open
Abstract
Background Tuberculosis (TB) affects one third of the global population, and TB of the central nervous system (CNS-TB) is the most severe form of tuberculosis which often associates with high mortality. The pro-inflammatory cytokine tumour necrosis factor (TNF) plays a critical role in the initial and long-term host immune protection against Mycobacterium tuberculosis (M. tuberculosis) which involves the activation of innate immune cells and structure maintenance of granulomas. However, the contribution of TNF, in particular neuron-derived TNF, in the control of cerebral M. tuberculosis infection and its protective immune responses in the CNS were not clear. Methods We generated neuron-specific TNF-deficient (NsTNF−/−) mice and compared outcomes of disease against TNFf/f control and global TNF−/− mice. Mycobacterial burden in brains, lungs and spleens were compared, and cerebral pathology and cellular contributions analysed by microscopy and flow cytometry after M. tuberculosis infection. Activation of innate immune cells was measured by flow cytometry and cell function assessed by cytokine and chemokine quantification using enzyme-linked immunosorbent assay (ELISA). Results Intracerebral M. tuberculosis infection of TNF−/− mice rendered animals highly susceptible, accompanied by uncontrolled bacilli replication and eventual mortality. In contrast, NsTNF−/− mice were resistant to infection and presented with a phenotype similar to that in TNFf/f control mice. Impaired immunity in TNF−/− mice was associated with altered cytokine and chemokine synthesis in the brain and characterised by a reduced number of activated innate immune cells. Brain pathology reflected enhanced inflammation dominated by neutrophil influx. Conclusion Our data show that neuron-derived TNF has a limited role in immune responses, but overall TNF production is necessary for protective immunity against CNS-TB.
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Affiliation(s)
- Ngiambudulu M Francisco
- Division of Immunology, Department of Clinical Laboratory Science, Institute of Infectious Disease and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Observatory, Cape Town, 7925, South Africa.
| | - Nai-Jen Hsu
- Division of Immunology, Department of Clinical Laboratory Science, Institute of Infectious Disease and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Observatory, Cape Town, 7925, South Africa.
| | - Roanne Keeton
- Division of Immunology, Department of Clinical Laboratory Science, Institute of Infectious Disease and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Observatory, Cape Town, 7925, South Africa.
| | - Philippa Randall
- Division of Immunology, Department of Clinical Laboratory Science, Institute of Infectious Disease and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Observatory, Cape Town, 7925, South Africa.
| | - Boipelo Sebesho
- Division of Immunology, Department of Clinical Laboratory Science, Institute of Infectious Disease and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Observatory, Cape Town, 7925, South Africa.
| | - Nasiema Allie
- Division of Immunology, Department of Clinical Laboratory Science, Institute of Infectious Disease and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Observatory, Cape Town, 7925, South Africa. .,Division for Postgraduate Studies, University of the Western Cape, Bellville, South Africa.
| | - Dhirendra Govender
- Division of Anatomical Pathology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa. .,National Health Laboratory Service, Johannesburg, South Africa.
| | - Valerie Quesniaux
- Experimental and Molecular Immunology and Neurogenetics, University of Orleans, Orleans, France. .,CNRS UMR7355, Orleans, France.
| | - Bernhard Ryffel
- Experimental and Molecular Immunology and Neurogenetics, University of Orleans, Orleans, France. .,CNRS UMR7355, Orleans, France.
| | - Lauriston Kellaway
- Department of Human Biology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa.
| | - Muazzam Jacobs
- Division of Immunology, Department of Clinical Laboratory Science, Institute of Infectious Disease and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Observatory, Cape Town, 7925, South Africa. .,National Health Laboratory Service, Johannesburg, South Africa.
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Takamatsu Y, Uchida L, Morita K. Delayed IFN response differentiates replication of West Nile virus and Japanese encephalitis virus in human neuroblastoma and glioblastoma cells. J Gen Virol 2015; 96:2194-2199. [PMID: 25920530 DOI: 10.1099/vir.0.000168] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
West Nile virus (WNV) and Japanese encephalitis virus (JEV) are important causes of human encephalitis cases, which result in a high mortality ratio and neurological sequelae after recovery. Understanding the mechanism of neuropathogenicity in these viral infections is important for the development of specific antiviral therapy. Here, we focused on human-derived neuronal and glial cells to understand the cellular responses against WNV and JEV infection. It was demonstrated that early IFN-β induction regulated virus replication in glioblastoma tbl98G cells, whereas delayed IFN-β induction resulted in efficient virus replication in neuroblastoma SK-N-SH cells. Moreover, the concealing of viral dsRNA in the intracellular membrane resulted in the delayed IFN response in SK-N-SH cells. These results, which showed different IFN responses between human neuronal and glial cells after WNV or JEV infection, are expected to contribute to our understanding of the molecular mechanisms for neuropathology in these viral infections.
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Affiliation(s)
- Yuki Takamatsu
- Department of Virology, Institute of Tropical Medicine, Nagasaki University, Nagasaki, Japan
| | - Leo Uchida
- Department of Virology, Institute of Tropical Medicine, Nagasaki University, Nagasaki, Japan
| | - Kouichi Morita
- Department of Virology, Institute of Tropical Medicine, Nagasaki University, Nagasaki, Japan
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64
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Swanson PA, McGavern DB. Viral diseases of the central nervous system. Curr Opin Virol 2015; 11:44-54. [PMID: 25681709 DOI: 10.1016/j.coviro.2014.12.009] [Citation(s) in RCA: 201] [Impact Index Per Article: 22.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2014] [Accepted: 12/17/2014] [Indexed: 11/18/2022]
Abstract
Virus-induced diseases of the central nervous system (CNS) represent a significant burden to human health worldwide. The complexity of these diseases is influenced by the sheer number of different neurotropic viruses, the diverse routes of CNS entry, viral tropism, and the immune system. Using a combination of human pathological data and experimental animal models, we have begun to uncover many of the mechanisms that viruses use to enter the CNS and cause disease. This review highlights a selection of neurotropic viruses that infect the CNS and explores the means by which they induce neurological diseases such as meningitis, encephalitis, and myelitis.
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Affiliation(s)
- Phillip A Swanson
- National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, United States
| | - Dorian B McGavern
- National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, United States.
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High-mobility group box-1, promising serological biomarker for the distinction of human WNV disease severity. Virus Res 2015; 195:9-12. [DOI: 10.1016/j.virusres.2014.08.017] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2014] [Revised: 08/22/2014] [Accepted: 08/27/2014] [Indexed: 12/12/2022]
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66
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Chugh PE, Damania BA, Dittmer DP. Toll-like receptor-3 is dispensable for the innate microRNA response to West Nile virus (WNV). PLoS One 2014; 9:e104770. [PMID: 25127040 PMCID: PMC4134228 DOI: 10.1371/journal.pone.0104770] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2014] [Accepted: 07/16/2014] [Indexed: 12/28/2022] Open
Abstract
The innate immune response to West Nile virus (WNV) infection involves recognition through toll-like receptors (TLRs) and RIG-I-like receptors (RLRs), leading to establishment of an antiviral state. MiRNAs (miRNAs) have been shown to be reliable biomarkers of TLR activation. Here, we sought to evaluate the contribution of TLR3 and miRNAs to the host response to WNV infection. We first analyzed HEK293-NULL and HEK293-TLR3 cells for changes in the innate immune response to infection. The presence of TLR3 did not seem to affect WNV load, infectivity or phosphorylation of IRF3. Analysis of experimentally validated NFκB-responsive genes revealed a WNV-induced signature largely independent of TLR3. Since miRNAs are involved in viral pathogenesis and the innate response to infection, we sought to identify changes in miRNA expression upon infection in the presence or absence of TLR3. MiRNA profiling revealed 70 miRNAs induced following WNV infection in a TLR3-independent manner. Further analysis of predicted gene targets of WNV signature miRNAs revealed genes highly associated with pathways regulating cell death, viral pathogenesis and immune cell trafficking.
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Affiliation(s)
- Pauline E. Chugh
- Department of Microbiology and Immunology, Lineberger Comprehensive Cancer Center, Center for AIDS Research, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Blossom A. Damania
- Department of Microbiology and Immunology, Lineberger Comprehensive Cancer Center, Center for AIDS Research, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Dirk P. Dittmer
- Department of Microbiology and Immunology, Lineberger Comprehensive Cancer Center, Center for AIDS Research, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
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67
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Myint KSA, Kipar A, Jarman RG, Gibbons RV, Perng GC, Flanagan B, Mongkolsirichaikul D, Van Gessel Y, Solomon T. Neuropathogenesis of Japanese encephalitis in a primate model. PLoS Negl Trop Dis 2014; 8:e2980. [PMID: 25102067 PMCID: PMC4125110 DOI: 10.1371/journal.pntd.0002980] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2013] [Accepted: 05/13/2014] [Indexed: 11/19/2022] Open
Abstract
Background Japanese encephalitis (JE) is a major cause of mortality and morbidity for which there is no treatment. In addition to direct viral cytopathology, the inflammatory response is postulated to contribute to the pathogenesis. Our goal was to determine the contribution of bystander effects and inflammatory mediators to neuronal cell death. Methodology/Principal Findings Material from a macaque model was used to characterize the inflammatory response and cytopathic effects of JE virus (JEV). Intranasal JEV infection induced a non-suppurative encephalitis, dominated by perivascular, infiltrates of mostly T cells, alongside endothelial cell activation, vascular damage and blood brain barrier (BBB) leakage; in the adjacent parenchyma there was macrophage infiltration, astrocyte and microglia activation. JEV antigen was mostly in neurons, but there was no correlation between intensity of viral infection and degree of inflammatory response. Apoptotic cell death occurred in both infected and non-infected neurons. Interferon-α, which is a microglial activator, was also expressed by both. Tumour Necrosis Factor-α, inducible nitric oxide synthase and nitrotyrosine were expressed by microglial cells, astrocytes and macrophages. The same cells expressed matrix metalloproteinase (MMP)-2 whilst MMP-9 was expressed by neurons. Conclusions/Significance The results are consistent with JEV inducing neuronal apoptotic death and release of cytokines that initiate microglial activation and release of pro-inflammatory and apoptotic mediators with subsequent apoptotic death of both infected and uninfected neurons. Activation of astrocytes, microglial and endothelial cells likely contributes to inflammatory cell recruitment and BBB breakdown. It appears that neuronal apoptotic death and activation of microglial cells and astrocytes play a crucial role in the pathogenesis of JE. Japanese encephalitis (JE) is one of the most important causes of viral encephalitis worldwide, with no specific antiviral treatment available. Despite some recent successes with widespread vaccination, JE will likely remain an important public health problem; because the virus is mosquito-borne and has natural animal hosts, it will never be eradicated. We have little understanding of what determines the severity and outcome of infection. Data from human post mortem studies is very limited because of cultural constraints on autopsies in areas where JE occurs. Circumstantial evidence suggests that in addition to cytopathology caused directly by infection of neurons, there may be bystander cell death of non-infected neurons, caused by an excessive inflammatory response. Our study used archived brain samples from a prior challenge study in a validated macaque model of JE. We stained for the presence of JEV antigen, apoptosis, and pro-inflammatory markers in affected areas, such as the thalamus and brainstem. We show that bystander neuronal cell death is important, and elucidate the inflammatory and apoptotic mechanisms underlying it. Currently there is no proven efficacious therapy for most viral infections of the central nervous system, including JE. Novel strategies for treating such infections are urgently needed. Our findings suggest new anti-inflammatory and anti-apoptotic therapeutic approaches may be useful in treating this debilitating disease.
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Affiliation(s)
- Khin Saw Aye Myint
- Armed Forces Research Institute of Medical Sciences (AFRIMS), Bangkok, Thailand
- Brain Infections Group, Institute of Infection and Global Health, University of Liverpool, NIHR Health Protection Research Unit in Emerging and Zoonotic Infections, and Walton Centre NHS Foundation Trust, Liverpool, United Kingdom
| | - Anja Kipar
- Veterinary Pathology, School of Veterinary Science, and Department of Infection Biology, Institute of Global Health, University of Liverpool, Liverpool, United Kingdom
| | - Richard G. Jarman
- Armed Forces Research Institute of Medical Sciences (AFRIMS), Bangkok, Thailand
| | - Robert V. Gibbons
- Armed Forces Research Institute of Medical Sciences (AFRIMS), Bangkok, Thailand
| | - Guey Chuen Perng
- Emory Vaccine Center, Emory University School of Medicine, Atlanta, Georgia, United States of America
- Department of Microbiology and Immunology, College of Medicine, National Cheng Kung University, Tainan, Taiwan
- Center of Infectious Disease and Signal Research, National Cheng Kung University, Tainan, Taiwan
| | - Brian Flanagan
- Infection Immunology, Department of Clinical Infection, Microbiology and Immunology, Institute of Infection and Global Health, University of Liverpool, Liverpool, United Kingdom
| | | | - Yvonne Van Gessel
- Armed Forces Research Institute of Medical Sciences (AFRIMS), Bangkok, Thailand
| | - Tom Solomon
- Brain Infections Group, Institute of Infection and Global Health, University of Liverpool, NIHR Health Protection Research Unit in Emerging and Zoonotic Infections, and Walton Centre NHS Foundation Trust, Liverpool, United Kingdom
- * E-mail:
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68
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Suen WW, Prow NA, Hall RA, Bielefeldt-Ohmann H. Mechanism of West Nile virus neuroinvasion: a critical appraisal. Viruses 2014; 6:2796-825. [PMID: 25046180 PMCID: PMC4113794 DOI: 10.3390/v6072796] [Citation(s) in RCA: 87] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2014] [Revised: 07/09/2014] [Accepted: 07/10/2014] [Indexed: 12/11/2022] Open
Abstract
West Nile virus (WNV) is an important emerging neurotropic virus, responsible for increasingly severe encephalitis outbreaks in humans and horses worldwide. However, the mechanism by which the virus gains entry to the brain (neuroinvasion) remains poorly understood. Hypotheses of hematogenous and transneural entry have been proposed for WNV neuroinvasion, which revolve mainly around the concepts of blood-brain barrier (BBB) disruption and retrograde axonal transport, respectively. However, an over‑representation of in vitro studies without adequate in vivo validation continues to obscure our understanding of the mechanism(s). Furthermore, WNV infection in the current rodent models does not generate a similar viremia and character of CNS infection, as seen in the common target hosts, humans and horses. These differences ultimately question the applicability of rodent models for pathogenesis investigations. Finally, the role of several barriers against CNS insults, such as the blood-cerebrospinal fluid (CSF), the CSF-brain and the blood-spinal cord barriers, remain largely unexplored, highlighting the infancy of this field. In this review, a systematic and critical appraisal of the current evidence relevant to the possible mechanism(s) of WNV neuroinvasion is conducted.
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Affiliation(s)
- Willy W Suen
- School of Veterinary Science, University of Queensland, Gatton, QLD, 4343, Australia.
| | - Natalie A Prow
- Australian Infectious Diseases Research Centre, University of Queensland, St. Lucia, QLD, 4072, Australia.
| | - Roy A Hall
- Australian Infectious Diseases Research Centre, University of Queensland, St. Lucia, QLD, 4072, Australia.
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69
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Palus M, Bílý T, Elsterová J, Langhansová H, Salát J, Vancová M, Růžek D. Infection and injury of human astrocytes by tick-borne encephalitis virus. J Gen Virol 2014; 95:2411-2426. [PMID: 25000960 DOI: 10.1099/vir.0.068411-0] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Tick-borne encephalitis (TBE), a disease caused by tick-borne encephalitis virus (TBEV), represents the most important flaviviral neural infection in Europe and north-eastern Asia. In the central nervous system (CNS), neurons are the primary target for TBEV infection; however, infection of non-neuronal CNS cells, such as astrocytes, is not well understood. In this study, we investigated the interaction between TBEV and primary human astrocytes. We report for the first time, to the best of our knowledge, that primary human astrocytes are sensitive to TBEV infection, although the infection did not affect their viability. The infection induced a marked increase in the expression of glial fibrillary acidic protein, a marker of astrocyte activation. In addition, expression of matrix metalloproteinase 9 and several key pro-inflammatory cytokines/chemokines (e.g. tumour necrosis factor α, interferon α, interleukin (IL)-1β, IL-6, IL-8, interferon γ-induced protein 10, macrophage inflammatory protein, but not monocyte chemotactic protein 1) was upregulated. Moreover, we present a detailed description of morphological changes in TBEV-infected cells, as investigated using three-dimensional electron tomography. Several novel ultrastructural changes were observed, including the formation of unique tubule-like structures of 17.9 ±0.15 nm diameter with associated viral particles and/or virus-induced vesicles and located in the rough endoplasmic reticulum of the TBEV-infected cells. This is the first demonstration that TBEV infection activates primary human astrocytes. The infected astrocytes might be a potential source of pro-inflammatory cytokines in the TBEV-infected brain, and might contribute to the TBEV-induced neurotoxicity and blood-brain barrier breakdown that occurs during TBE. The neuropathological significance of our observations is also discussed.
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Affiliation(s)
- Martin Palus
- Faculty of Science, University of South Bohemia, Branišovská 31, CZ-37005 České Budějovice, Czech Republic.,Institute of Parasitology, Biology Centre of the Academy of Sciences of the Czech Republic, Branišovská 31, CZ-37005 České Budějovice, Czech Republic.,Department of Virology, Veterinary Research Institute, Hudcova 70, CZ-62100 Brno, Czech Republic
| | - Tomáš Bílý
- Faculty of Science, University of South Bohemia, Branišovská 31, CZ-37005 České Budějovice, Czech Republic.,Institute of Parasitology, Biology Centre of the Academy of Sciences of the Czech Republic, Branišovská 31, CZ-37005 České Budějovice, Czech Republic
| | - Jana Elsterová
- Department of Virology, Veterinary Research Institute, Hudcova 70, CZ-62100 Brno, Czech Republic.,Faculty of Science, University of South Bohemia, Branišovská 31, CZ-37005 České Budějovice, Czech Republic.,Institute of Parasitology, Biology Centre of the Academy of Sciences of the Czech Republic, Branišovská 31, CZ-37005 České Budějovice, Czech Republic
| | - Helena Langhansová
- Faculty of Science, University of South Bohemia, Branišovská 31, CZ-37005 České Budějovice, Czech Republic.,Institute of Parasitology, Biology Centre of the Academy of Sciences of the Czech Republic, Branišovská 31, CZ-37005 České Budějovice, Czech Republic
| | - Jiří Salát
- Department of Virology, Veterinary Research Institute, Hudcova 70, CZ-62100 Brno, Czech Republic
| | - Marie Vancová
- Faculty of Science, University of South Bohemia, Branišovská 31, CZ-37005 České Budějovice, Czech Republic.,Institute of Parasitology, Biology Centre of the Academy of Sciences of the Czech Republic, Branišovská 31, CZ-37005 České Budějovice, Czech Republic
| | - Daniel Růžek
- Department of Virology, Veterinary Research Institute, Hudcova 70, CZ-62100 Brno, Czech Republic.,Faculty of Science, University of South Bohemia, Branišovská 31, CZ-37005 České Budějovice, Czech Republic.,Institute of Parasitology, Biology Centre of the Academy of Sciences of the Czech Republic, Branišovská 31, CZ-37005 České Budějovice, Czech Republic
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70
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Innate immune responses regulate morphogenesis and degeneration: roles of Toll-like receptors and Sarm1 in neurons. Neurosci Bull 2014; 30:645-54. [PMID: 24993772 DOI: 10.1007/s12264-014-1445-5] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2014] [Accepted: 04/28/2014] [Indexed: 10/25/2022] Open
Abstract
The central nervous system is recognized as an immunoprivileged site because peripheral immune cells do not typically enter it. Microglial cells are thought to be the main immune cells in brain. However, recent reports have indicated that neurons express the key players of innate immunity, including Toll-like receptors (TLRs) and their adaptor proteins (Sarm1, Myd88, and Trif), and may produce cytokines in response to pathogen infection. In the absence of an immune challenge, neuronal TLRs can detect intrinsic danger signals and modulate neuronal morphology and function. In this article, we review the recent findings on the involvement of TLRs and Sarm1 in controlling neuronal morphogenesis and neurodegeneration. Abnormal behaviors in TLR- and Sarm1-deficient mice are also discussed.
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71
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Hussmann KL, Vandergaast R, Zheng K, Hoover LI, Fredericksen BL. Structural proteins of West Nile virus are a major determinant of infectious particle production and fitness in astrocytes. J Gen Virol 2014; 95:1991-2003. [PMID: 24920724 PMCID: PMC4135089 DOI: 10.1099/vir.0.065474-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The molecular basis for the increased resistance of astrocytes to a non-neuropathogenic strain of West Nile virus (WNV), WNV-MAD78, compared with the neuropathogenic strain WNV-NY remains unclear. Here, we demonstrated that the reduced susceptibility of astrocytes to WNV-MAD78 is due to a combination of both cellular activities as well as viral determinants. Analyses of the viral particle indicated that astrocyte-derived WNV-MAD78 particles were less infectious than those of WNV-NY. Additionally, inhibition of cellular furin-like proteases increased WNV-MAD78 infectious particle production in astrocytes, suggesting that high levels of furin-like protease activity within these cells acted in a cell- and strain-specific manner to inhibit WNV-MAD78 replication. Moreover, analysis of recombinant viruses indicated that the structural proteins of WNV-MAD78 were responsible for decreased particle infectivity and the corresponding reduction in infectious particle production compared with WNV-NY. Thus, the composition of the WNV virion was also a major determinant for viral fitness within astrocytes and may contribute to WNV propagation within the central nervous system. Whether the WNV-MAD78 structural genes reduce virus replication and particle infectivity through the same mechanism as the cellular furin-like protease activity or whether these two determinants function through distinct pathways remains to be determined.
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Affiliation(s)
- Katherine L Hussmann
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD 20742, USA
| | - Rianna Vandergaast
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD 20742, USA
| | - Kang Zheng
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD 20742, USA
| | - Lisa I Hoover
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD 20742, USA
| | - Brenda L Fredericksen
- Maryland Pathogen Research Institute, University of Maryland, College Park, MD 20742, USA.,Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD 20742, USA
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72
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Infection with non-lethal West Nile virus Eg101 strain induces immunity that protects mice against the lethal West Nile virus NY99 strain. Viruses 2014; 6:2328-39. [PMID: 24915459 PMCID: PMC4074930 DOI: 10.3390/v6062328] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2014] [Revised: 05/25/2014] [Accepted: 05/30/2014] [Indexed: 12/19/2022] Open
Abstract
Herein we demonstrate that infection of mice with West Nile virus (WNV) Eg101 provides protective immunity against lethal challenge with WNV NY99. Our data demonstrated that WNV Eg101 is largely non-virulent in adult mice when compared to WNV NY99. By day 6 after infection, WNV-specific IgM and IgG antibodies, and neutralizing antibodies were detected in the serum of all WNV Eg101 infected mice. Plaque reduction neutralization test data demonstrated that serum from WNV Eg101 infected mice neutralized WNV Eg101 and WNV NY99 strains with similar efficiency. Three weeks after infection, WNV Eg101 immunized mice were challenged subcutaneously or intracranially with lethal dose of WNV NY99 and observed for additional three weeks. All the challenged mice were protected against disease and no morbidity and mortality was observed in any mice. In conclusion, our data for the first time demonstrate that infection of mice with WNV Eg101 induced high titers of WNV specific IgM and IgG antibodies, and cross-reactive neutralizing antibodies, and the resulting immunity protected all immunized animals from both subcutaneous and intracranial challenge with WNV NY99. These observations suggest that WNV Eg101 may be a suitable strain for the development of a vaccine in humans against virulent strains of WNV.
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73
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Up-regulation of pro-inflammatory factors by HP-PRRSV infection in microglia: Implications for HP-PRRSV neuropathogenesis. Vet Microbiol 2014; 170:48-57. [DOI: 10.1016/j.vetmic.2014.01.031] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2013] [Revised: 01/24/2014] [Accepted: 01/28/2014] [Indexed: 11/24/2022]
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74
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Kumar M, Roe K, Nerurkar PV, Orillo B, Thompson KS, Verma S, Nerurkar VR. Reduced immune cell infiltration and increased pro-inflammatory mediators in the brain of Type 2 diabetic mouse model infected with West Nile virus. J Neuroinflammation 2014; 11:80. [PMID: 24750819 PMCID: PMC4001407 DOI: 10.1186/1742-2094-11-80] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2014] [Accepted: 04/11/2014] [Indexed: 01/02/2023] Open
Abstract
Background Diabetes is a significant risk factor for developing West Nile virus (WNV)-associated encephalitis (WNVE) in humans, the leading cause of arboviral encephalitis in the United States. Using a diabetic mouse model (db/db), we recently demonstrated that diabetes enhanced WNV replication and the susceptibility of mice to WNVE. Herein, we have examined immunological events in the brain of wild type (WT) and db/db mice after WNV infection. We hypothesized that WNV-induced migration of protective leukocytes into the brain is attenuated in the presence of diabetes, leading to a high viral load in the brain and severe disease in diabetic mice. Methods Nine-week old C57BL/6 WT and db/db mice were infected with WNV. Leukocyte infiltration, expression of cell adhesion molecules (CAM), neuroinflammatory responses, activation of astrocytes, and neuronal death were analyzed using immunohistochemistry, qRT-PCR, flow cytometry, and western blot. Results We demonstrate that infiltration of CD45+ leukocytes and CD8+T cells was significantly reduced in the brains of db/db mice, which was correlated with attenuated expression of CAM such as E-selectin and ICAM-1. WNV infection in db/db mice was associated with an enhanced inflammatory response in the brain. mRNA and protein levels of key chemokines such as CXCL10, CXCL1, CCL2, CCL5, CCL3, and G-CSF, and cytokines such as IL-1β, TNF, IL-6, IFNγ, and IL-1α were significantly elevated in the brains of db/db mice compared to WT mice. Elevated levels of cytokines also correlated with increased astrocytes activation and neuronal damage in the brains of db/db mice. Conclusion These data suggest that reduced leukocytes recruitment, in part, due to lower levels of CAM results in failure to clear WNV infection from the brain leading to increased production of inflammatory molecules, which mediates increased neuronal death and mortality in db/db mice. This is the first study to elucidate the expression of CAM and their correlation with the migration of leukocytes, specifically cytotoxic CD8+ T cells, in increasing disease severity in the diabetic mouse model.
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Affiliation(s)
| | | | | | | | | | | | - Vivek R Nerurkar
- Department of Tropical Medicine, Medical Microbiology and Pharmacology, John A, Burns School of Medicine, University of Hawaii at Manoa, 651 Ilalo Street, BSB 320G, Honolulu, Hawaii 96813, USA.
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75
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Hoyo-Becerra C, Huebener A, Trippler M, Lutterbeck M, Liu ZJ, Truebner K, Bajanowski T, Gerken G, Hermann DM, Schlaak JF. Concomitant interferon alpha stimulation and TLR3 activation induces neuronal expression of depression-related genes that are elevated in the brain of suicidal persons. PLoS One 2013; 8:e83149. [PMID: 24391741 PMCID: PMC3877033 DOI: 10.1371/journal.pone.0083149] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2013] [Accepted: 10/30/2013] [Indexed: 02/07/2023] Open
Abstract
We have previously identified 15 genes that are associated with the development of severe depressive side effects during the standard therapy with interferon alpha and ribavirin in the peripheral blood of hepatitis C virus infected patients. An enhanced expression of these genes was also found in the blood of psychiatric patients suffering severe depressive episode. Herein, we demonstrate that the same depression-related interferon-inducible genes (DRIIs) are also upregulated in post-mortem brains of suicidal individuals. Using cultured mouse hippocampal and prefrontal neurons we show that costimulation with murine IFN (mIFN) and the TLR3 agonist poly(I:C) promotes the expression of the described DRIIs, at the same time inducing pro-inflammatory cytokine expression through Stat1 and Stat3 activation, promoting neuronal apoptosis. Consequently, the upregulation of selective DRIIs, production of inflammatory cytokines and inhibition of neuronal plasticity may be involved in the pathogenesis of IFN-associated depression.
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Affiliation(s)
- Carolina Hoyo-Becerra
- Department of Gastroenterology and Hepatology, University Hospital of Essen, Essen, Germany
| | - Anastasia Huebener
- Department of Gastroenterology and Hepatology, University Hospital of Essen, Essen, Germany
| | - Martin Trippler
- Department of Gastroenterology and Hepatology, University Hospital of Essen, Essen, Germany
| | - Melanie Lutterbeck
- Department of Gastroenterology and Hepatology, University Hospital of Essen, Essen, Germany
| | - Zijian J. Liu
- Department of Anatomy, Tongji Medical College of Huazhong, University of Science and Technology, Wuhan City, P.R.China
| | - Kurt Truebner
- Institute for Forensic Medicine, University Hospital of Essen, Essen, Germany
| | - Thomas Bajanowski
- Institute for Forensic Medicine, University Hospital of Essen, Essen, Germany
| | - Guido Gerken
- Department of Gastroenterology and Hepatology, University Hospital of Essen, Essen, Germany
| | - Dirk M. Hermann
- Department of Neurology, University Hospital of Essen, Essen, Germany
| | - Joerg F. Schlaak
- Department of Gastroenterology and Hepatology, University Hospital of Essen, Essen, Germany
- * E-mail:
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76
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Donadieu E, Bahuon C, Lowenski S, Zientara S, Coulpier M, Lecollinet S. Differential virulence and pathogenesis of West Nile viruses. Viruses 2013; 5:2856-80. [PMID: 24284878 PMCID: PMC3856419 DOI: 10.3390/v5112856] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2013] [Revised: 11/13/2013] [Accepted: 11/14/2013] [Indexed: 12/21/2022] Open
Abstract
West Nile virus (WNV) is a neurotropic flavivirus that cycles between mosquitoes and birds but that can also infect humans, horses, and other vertebrate animals. In most humans, WNV infection remains subclinical. However, 20%-40% of those infected may develop WNV disease, with symptoms ranging from fever to meningoencephalitis. A large variety of WNV strains have been described worldwide. Based on their genetic differences, they have been classified into eight lineages; the pathogenic strains belong to lineages 1 and 2. Ten years ago, Beasley et al. (2002) found that dramatic differences exist in the virulence and neuroinvasion properties of lineage 1 and lineage 2 WNV strains. Further insights on how WNV interacts with its hosts have recently been gained; the virus acts either at the periphery or on the central nervous system (CNS), and these observed differences could help explain the differential virulence and neurovirulence of WNV strains. This review aims to summarize the current state of knowledge on factors that trigger WNV dissemination and CNS invasion as well as on the inflammatory response and CNS damage induced by WNV. Moreover, we will discuss how WNV strains differentially interact with the innate immune system and CNS cells, thus influencing WNV pathogenesis.
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Affiliation(s)
- Emilie Donadieu
- Université Paris Est Créteil (UPEC), UMR 1161 Virologie, Institut National de la Recherche Agronomique (INRA), Agence nationale de sécurité sanitaire de l'alimentation, de l'environnement et du travail (ANSES) , Ecole Nationale Vétérinaire d'Alfort (ENVA), 7 avenue du Général De Gaulle, Maisons-Alfort 94700, France.
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Affiliation(s)
- Mehul S. Suthar
- Department of Pediatrics and Children's Healthcare of Atlanta and Emory Vaccine Center, Emory University School of Medicine, Atlanta, Georgia, United States of America
| | - Sebastian Aguirre
- Department of Microbiology and the Emerging Pathogens Institute, Icahn School of Medicine at Mount Sinai, New York, New York, United States of America
| | - Ana Fernandez-Sesma
- Department of Microbiology and the Emerging Pathogens Institute, Icahn School of Medicine at Mount Sinai, New York, New York, United States of America
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Ramesh G, MacLean AG, Philipp MT. Cytokines and chemokines at the crossroads of neuroinflammation, neurodegeneration, and neuropathic pain. Mediators Inflamm 2013; 2013:480739. [PMID: 23997430 PMCID: PMC3753746 DOI: 10.1155/2013/480739] [Citation(s) in RCA: 409] [Impact Index Per Article: 37.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2013] [Revised: 07/11/2013] [Accepted: 07/12/2013] [Indexed: 01/18/2023] Open
Abstract
Cytokines and chemokines are proteins that coordinate the immune response throughout the body. The dysregulation of cytokines and chemokines is a central feature in the development of neuroinflammation, neurodegeneration, and demyelination both in the central and peripheral nervous systems and in conditions of neuropathic pain. Pathological states within the nervous system can lead to activation of microglia. The latter may mediate neuronal and glial cell injury and death through production of proinflammatory factors such as cytokines and chemokines. These then help to mobilize the adaptive immune response. Although inflammation may induce beneficial effects such as pathogen clearance and phagocytosis of apoptotic cells, uncontrolled inflammation can result in detrimental outcomes via the production of neurotoxic factors that exacerbate neurodegenerative pathology. In states of prolonged inflammation, continual activation and recruitment of effector cells can establish a feedback loop that perpetuates inflammation and ultimately results in neuronal injury. A critical balance between repair and proinflammatory factors determines the outcome of a neurodegenerative process. This review will focus on how cytokines and chemokines affect neuroinflammation and disease pathogenesis in bacterial meningitis and brain abscesses, Lyme neuroborreliosis, human immunodeficiency virus encephalitis, and neuropathic pain.
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Affiliation(s)
- Geeta Ramesh
- Division of Bacteriology and Parasitology, Tulane National Primate Research Center, Tulane University, 18703 Three Rivers Road, Covington, LA 70433, USA.
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Induction of an inflammatory loop by interleukin-1β and tumor necrosis factor-α involves NF-kB and STAT-1 in differentiated human neuroprogenitor cells. PLoS One 2013; 8:e69585. [PMID: 23922745 PMCID: PMC3726669 DOI: 10.1371/journal.pone.0069585] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2013] [Accepted: 06/12/2013] [Indexed: 12/04/2022] Open
Abstract
Proinflammatory cytokines secreted from microglia are known to induce a secondary immune response in astrocytes leading to an inflammatory loop. Cytokines also interfere with neurogenesis during aging and in neurodegenerative diseases. The present study examined the mechanism of induction of inflammatory mediators at the transcriptional level in human differentiated neuroprogenitor cells (NPCs). Interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α) induced the expression of cytokines and chemokines in differentiated human NPCs as shown by an immune pathway-specific array. Network motif (NM) analysis of these genes revealed 118 three-node NMs, suggesting complex interactions between inflammatory mediators and transcription factors. Immunofluorescent staining showed increases in the levels of IL-8 and CXCL10 proteins in neurons and glial cells. Findings from Taqman low density array suggested the synergistic actions of IL-1β and TNF-α in the induction of a majority of inflammatory genes by a mechanism involving NF-kB and STAT-1. Nuclear localization of these transcription factors in differentiated NPCs was observed following exposure to IL-1α and TNF-α. Further studies on CXCL10, a chemokine known to be elevated in the Alzheimer's brain, showed that TNF-α is a stronger inducer of CXCL10 promoter when compared to IL-1β. The synergy between these cytokines was lost when ISRE or kB elements in CXCL10 promoter were mutated. Our findings suggest that the activation of inflammatory pathways in neurons and astrocytes through transcription factors including NF-kB and STAT-1 play important roles in neuroglial interactions and in sustaining the vicious cycle of inflammatory response.
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80
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Fredericksen BL. The neuroimmune response to West Nile virus. J Neurovirol 2013; 20:113-21. [PMID: 23843081 PMCID: PMC3971464 DOI: 10.1007/s13365-013-0180-z] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2013] [Revised: 05/28/2013] [Accepted: 06/14/2013] [Indexed: 02/07/2023]
Abstract
The recent introduction of highly pathogenic strains of West Nile virus (WNV) into naïve populations in Europe, Israel, and the USA has resulted in a marked increase in both the number of reported cases and the severity of disease compared to previous outbreaks. The impact of the increased virulence of recently emerged strains of WNV is exacerbated by the fact that antiviral therapies and vaccines are not currently available for use in humans. A greater understanding of the viral and host factors involved in WNV-mediated neuropathology is necessary to facilitate the development of novel therapeutic approaches. This review summarizes the current state of knowledge of the role of the cell-intrinsic innate immune responses as well as the cell-mediated innate and adaptive immune responses in promoting the detection and clearance of WNV from the CNS.
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Affiliation(s)
- Brenda L Fredericksen
- Department of Cell Biology and Molecular Genetics, University of Maryland College Park, 3126 Biosciences Research Bldg, College Park, MD, 20742, USA,
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81
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Altered protein networks and cellular pathways in severe west nile disease in mice. PLoS One 2013; 8:e68318. [PMID: 23874584 PMCID: PMC3707916 DOI: 10.1371/journal.pone.0068318] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2013] [Accepted: 05/28/2013] [Indexed: 01/25/2023] Open
Abstract
Background The recent West Nile virus (WNV) outbreaks in developed countries, including Europe and the United States, have been associated with significantly higher neuropathology incidence and mortality rate than previously documented. The changing epidemiology, the constant risk of (re-)emergence of more virulent WNV strains, and the lack of effective human antiviral therapy or vaccines makes understanding the pathogenesis of severe disease a priority. Thus, to gain insight into the pathophysiological processes in severe WNV infection, a kinetic analysis of protein expression profiles in the brain of WNV-infected mice was conducted using samples prior to and after the onset of clinical symptoms. Methodology/Principal Findings To this end, 2D-DIGE and gel-free iTRAQ labeling approaches were combined, followed by protein identification by mass spectrometry. Using these quantitative proteomic approaches, a set of 148 proteins with modified abundance was identified. The bioinformatics analysis (Ingenuity Pathway Analysis) of each protein dataset originating from the different time-point comparisons revealed that four major functions were altered during the course of WNV-infection in mouse brain tissue: i) modification of cytoskeleton maintenance associated with virus circulation; ii) deregulation of the protein ubiquitination pathway; iii) modulation of the inflammatory response; and iv) alteration of neurological development and neuronal cell death. The differential regulation of selected host protein candidates as being representative of these biological processes were validated by western blotting using an original fluorescence-based method. Conclusion/Significance This study provides novel insights into the in vivo kinetic host reactions against WNV infection and the pathophysiologic processes involved, according to clinical symptoms. This work offers useful clues for anti-viral research and further evaluation of early biomarkers for the diagnosis and prevention of severe neurological disease caused by WNV.
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Rossini G, Landini MP, Gelsomino F, Sambri V, Varani S. Innate host responses to West Nile virus: Implications for central nervous system immunopathology. World J Virol 2013; 2:49-56. [PMID: 24175229 PMCID: PMC3785052 DOI: 10.5501/wjv.v2.i2.49] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/05/2012] [Revised: 01/19/2013] [Accepted: 02/06/2013] [Indexed: 02/05/2023] Open
Abstract
West Nile virus (WNV) is an emerging neurotropic flavivirus that has recently spread to America and Southern Europe via an enzootic/epizootic bird-mosquito-bird transmission cycle. The virus can occasionally infect humans through mosquito bites, and man-to-man transmission has also been reported via infected blood or organ donation. In the human host, WNV causes asymptomatic infection in about 70%-80% of cases, while < 1% of clinical cases progress to severe neuroinvasive disease; long-term neurological sequelae are common in more than 50% of these severe cases. The pathogenesis of the neuroinvasive form of WNV infection remains incompletely understood, and risk factors for developing severe clinical illness are largely unknown. The innate immune response plays a major role in the control of WNV replication, which is supported by the fact that the virus has developed numerous mechanisms to escape the control of antiviral interferons. However, exaggerated inflammatory responses lead to pathology, mainly involving the central nervous system. This brief review presents the salient features of innate host responses, WNV immunoevasion strategies, and WNV-induced immunopathology.
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Hussmann KL, Samuel MA, Kim KS, Diamond MS, Fredericksen BL. Differential replication of pathogenic and nonpathogenic strains of West Nile virus within astrocytes. J Virol 2013; 87:2814-22. [PMID: 23269784 PMCID: PMC3571364 DOI: 10.1128/jvi.02577-12] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2012] [Accepted: 12/15/2012] [Indexed: 12/13/2022] Open
Abstract
The severity of West Nile virus (WNV) infection in immunocompetent animals is highly strain dependent, ranging from avirulent to highly neuropathogenic. Here, we investigate the nature of this strain-specific restriction by analyzing the replication of avirulent (WNV-MAD78) and highly virulent (WNV-NY) strains in neurons, astrocytes, and microvascular endothelial cells, which comprise the neurovascular unit within the central nervous system (CNS). We demonstrate that WNV-MAD78 replicated in and traversed brain microvascular endothelial cells as efficiently as WNV-NY. Likewise, similar levels of replication were detected in neurons. Thus, WNV-MAD78's nonneuropathogenic phenotype is not due to an intrinsic inability to replicate in key target cells within the CNS. In contrast, replication of WNV-MAD78 was delayed and reduced compared to that of WNV-NY in astrocytes. The reduced susceptibility of astrocytes to WNV-MAD78 was due to a delay in viral genome replication and an interferon-independent reduction in cell-to-cell spread. Together, our data suggest that astrocytes regulate WNV spread within the CNS and therefore are an attractive target for ameliorating WNV-induced neuropathology.
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Affiliation(s)
- Katherine L. Hussmann
- Department of Cell Biology and Molecular Genetics, University of Maryland College Park, College Park, Maryland, USA
| | - Melanie A. Samuel
- Departments of Medicine, Molecular Microbiology, and Pathology & Immunology, Washington University, St. Louis, Missouri, USA
| | - Kwang S. Kim
- Department of Pediatrics, Division of Pediatric Infectious Diseases, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Michael S. Diamond
- Departments of Medicine, Molecular Microbiology, and Pathology & Immunology, Washington University, St. Louis, Missouri, USA
| | - Brenda L. Fredericksen
- Department of Cell Biology and Molecular Genetics, University of Maryland College Park, College Park, Maryland, USA
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84
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Suthar MS, Diamond MS, Gale Jr M. West Nile virus infection and immunity. Nat Rev Microbiol 2013; 11:115-28. [DOI: 10.1038/nrmicro2950] [Citation(s) in RCA: 300] [Impact Index Per Article: 27.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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Inflammasome adaptor protein Apoptosis-associated speck-like protein containing CARD (ASC) is critical for the immune response and survival in west Nile virus encephalitis. J Virol 2013; 87:3655-67. [PMID: 23302887 DOI: 10.1128/jvi.02667-12] [Citation(s) in RCA: 88] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
West Nile virus (WNV) is a neurotropic flavivirus that has emerged globally as a significant cause of viral encephalitis in humans. The WNV-induced innate immune response, including production of antiviral cytokines, is critical for controlling virus infection. The adaptor protein ASC mediates a critical step in innate immune signaling by bridging the interaction between the pathogen recognition receptors and caspase 1 in inflammasome complexes, but its role in WNV immunopathogenesis is not defined. Here, we demonstrate that ASC is essential for interleukin-1β (IL-1β) production and development of effective host immunity against WNV. ASC-deficient mice exhibited increased susceptibility to WNV infection, and reduced survival was associated with enhanced virus replication in the peripheral tissues and central nervous system (CNS). Infection of cultured bone marrow-derived dendritic cells showed that ASC was essential for the activation of caspase 1, a key component of inflammasome assembly. ASC(-/-) mice exhibited attenuated levels of proinflammatory cytokines in the serum. Intriguingly, infected ASC(-/-) mice also displayed reduced levels of alpha interferon (IFN-α) and IgM in the serum, indicating the overall protective role of ASC in restricting WNV infection. However, brains from ASC(-/-) mice displayed unrestrained inflammation, including elevated levels of proinflammatory cytokines and chemokines, such as IFN-γ, CCL2, and CCL5, which correlated with more pronounced activation of the astrocytes, enhanced infiltration of peripheral immune cells in the CNS, and increased neuronal cell death. Collectively, our data provide new insights into the role of ASC as an essential modulator of inflammasome-dependent and -independent immune responses to effectively control WNV infection.
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86
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Yiang GT, Chen YH, Chou PL, Chang WJ, Wei CW, Yu YL. The NS3 protease and helicase domains of Japanese encephalitis virus trigger cell death via caspase‑dependent and ‑independent pathways. Mol Med Rep 2013; 7:826-30. [PMID: 23291778 DOI: 10.3892/mmr.2013.1261] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2012] [Accepted: 12/04/2012] [Indexed: 11/06/2022] Open
Abstract
Japanese encephalitis virus (JEV), a mosquito‑borne flavivirus, causes acute encephalitis and nervous damage. Previous studies have demonstrated that JEV induces apoptosis in infected cells. However, to date the mechanisms of JEV‑induced apoptosis are unclear. In order to identify the viral proteins associated with JEV‑induced apoptosis, pEGFP‑non‑structural protein 3 (NS3) 1‑619 (expressing the JEV NS3 intact protein, including the protease and helicase domains), pEGFP‑NS3 1‑180 (expressing the protease domain) and pEGFP‑NS3 163‑619 (expressing the helicase domain) were transfected into target cells to study cell death. Results demonstrate that the JEV NS3 intact protein and protease and helicase domains induce cell death. In addition, cell death was identified to be significantly higher in cells transfected with the NS3 protease domain compared with the intact protein and helicase domain. Caspase activation was also analyzed in the current study. NS3 intact protein and NS3 protease and helicase domains activated caspase‑9/‑3‑dependent and ‑independent pathways. However, caspase‑8 activity was not found to be significantly different in NS3‑transfected cells compared with control. In summary, the present study demonstrates that the NS3 helicase and protease domains of JEV activate caspase‑9/‑3‑dependent and ‑independent cascades and trigger cell death.
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Affiliation(s)
- Giou-Teng Yiang
- Department of Emergency Medicine, Tzu Chi University, Hualien 970, Taiwan, ROC
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87
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HIF-1α is a protective factor in conditional PHD2-deficient mice suffering from severe HIF-2α-induced excessive erythropoiesis. Blood 2012; 121:1436-45. [PMID: 23264599 DOI: 10.1182/blood-2012-08-449181] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Erythropoiesis must be tightly balanced to guarantee adequate oxygen delivery to all tissues in the body. This process relies predominantly on the hormone erythropoietin (EPO) and its transcription factor hypoxia inducible factor (HIF). Accumulating evidence suggests that oxygen-sensitive prolyl hydroxylases (PHDs) are important regulators of this entire system. Here, we describe a novel mouse line with conditional PHD2 inactivation (cKO P2) in renal EPO producing cells, neurons, and astrocytes that displayed excessive erythrocytosis because of severe overproduction of EPO, exclusively driven by HIF-2α. In contrast, HIF-1α served as a protective factor, ensuring survival of cKO P2 mice with HCT values up to 86%. Using different genetic approaches, we show that simultaneous inactivation of PHD2 and HIF-1α resulted in a drastic PHD3 reduction with consequent overexpression of HIF-2α-related genes, neurodegeneration, and lethality. Taken together, our results demonstrate for the first time that conditional loss of PHD2 in mice leads to HIF-2α-dependent erythrocytosis, whereas HIF-1α protects these mice, providing a platform for developing new treatments of EPO-related disorders, such as anemia.
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88
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Immune responses to West Nile virus infection in the central nervous system. Viruses 2012; 4:3812-30. [PMID: 23247502 PMCID: PMC3528292 DOI: 10.3390/v4123812] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2012] [Revised: 12/07/2012] [Accepted: 12/10/2012] [Indexed: 12/16/2022] Open
Abstract
West Nile virus (WNV) continues to cause outbreaks of severe neuroinvasive disease in humans and other vertebrate animals in the United States, Europe, and other regions of the world. This review discusses our understanding of the interactions between virus and host that occur in the central nervous system (CNS), the outcome of which can be protection, viral pathogenesis, or immunopathogenesis. We will focus on defining the current state of knowledge of WNV entry, tropism, and host immune response in the CNS, all of which affect the balance between injury and successful clearance.
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89
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Kumar M, Roe K, Nerurkar PV, Namekar M, Orillo B, Verma S, Nerurkar VR. Impaired virus clearance, compromised immune response and increased mortality in type 2 diabetic mice infected with West Nile virus. PLoS One 2012; 7:e44682. [PMID: 22953001 PMCID: PMC3432127 DOI: 10.1371/journal.pone.0044682] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2012] [Accepted: 08/06/2012] [Indexed: 12/13/2022] Open
Abstract
Clinicoepidemiological data suggest that type 2 diabetes is associated with increased risk of West Nile virus encephalitis (WNVE). However, no experimental studies have elucidated the role of diabetes in WNV neuropathogenesis. Herein, we employed the db/db mouse model to understand WNV immunopathogenesis in diabetics. Nine-week old C57BL/6 WT and db/db mice were inoculated with WNV and mortality, virus burden in the periphery and brain, and antiviral defense responses were analyzed. db/db mice were highly susceptible to WNV disease, exhibited increased tissue tropism and mortality than the wild-type mice, and were unable to clear the infection. Increased and sustained WNV replication was observed in the serum, peripheral tissues and brain of db/db mice, and heightened virus replication in the periphery was correlated with enhanced neuroinvasion and replication of WNV in the brain. WNV infection in db/db mice was associated with enhanced inflammatory response and compromised antiviral immune response characterized by delayed induction of IFN-α, and significantly reduced concentrations of WNV-specific IgM and IgG antibodies. The compromised immune response in db/db mice correlated with increased viremia. These data suggest that delayed immune response coupled with failure to clear the virus leads to increased mortality in db/db mice. In conclusion, this study provides unique mechanistic insight into the immunopathogenesis of WNVE observed in diabetics and can be used to develop therapeutics for the management of WNVE among diabetic patients.
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Affiliation(s)
- Mukesh Kumar
- Department of Tropical Medicine, Medical Microbiology and Pharmacology, John A. Burns School of Medicine, University of Hawaii at Manoa, Honolulu, Hawaii, United States of America
- Pacific Center for Emerging Infectious Diseases Research, John A. Burns School of Medicine, University of Hawaii at Manoa, Honolulu, Hawaii, United States of America
| | - Kelsey Roe
- Department of Tropical Medicine, Medical Microbiology and Pharmacology, John A. Burns School of Medicine, University of Hawaii at Manoa, Honolulu, Hawaii, United States of America
- Pacific Center for Emerging Infectious Diseases Research, John A. Burns School of Medicine, University of Hawaii at Manoa, Honolulu, Hawaii, United States of America
| | - Pratibha V. Nerurkar
- Laboratory of Metabolic Disorders and Alternative Medicine, Department of Molecular Biosciences and Bioengineering, College of Tropical Agriculture and Human Resources, University of Hawaii at Manoa, Honolulu, Hawaii, United States of America
| | - Madhuri Namekar
- Department of Tropical Medicine, Medical Microbiology and Pharmacology, John A. Burns School of Medicine, University of Hawaii at Manoa, Honolulu, Hawaii, United States of America
- Pacific Center for Emerging Infectious Diseases Research, John A. Burns School of Medicine, University of Hawaii at Manoa, Honolulu, Hawaii, United States of America
| | - Beverly Orillo
- Department of Tropical Medicine, Medical Microbiology and Pharmacology, John A. Burns School of Medicine, University of Hawaii at Manoa, Honolulu, Hawaii, United States of America
- Pacific Center for Emerging Infectious Diseases Research, John A. Burns School of Medicine, University of Hawaii at Manoa, Honolulu, Hawaii, United States of America
| | - Saguna Verma
- Department of Tropical Medicine, Medical Microbiology and Pharmacology, John A. Burns School of Medicine, University of Hawaii at Manoa, Honolulu, Hawaii, United States of America
- Pacific Center for Emerging Infectious Diseases Research, John A. Burns School of Medicine, University of Hawaii at Manoa, Honolulu, Hawaii, United States of America
| | - Vivek R. Nerurkar
- Department of Tropical Medicine, Medical Microbiology and Pharmacology, John A. Burns School of Medicine, University of Hawaii at Manoa, Honolulu, Hawaii, United States of America
- Pacific Center for Emerging Infectious Diseases Research, John A. Burns School of Medicine, University of Hawaii at Manoa, Honolulu, Hawaii, United States of America
- * E-mail:
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90
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Leis AA, Stokic DS. Neuromuscular manifestations of west nile virus infection. Front Neurol 2012; 3:37. [PMID: 22461779 PMCID: PMC3309965 DOI: 10.3389/fneur.2012.00037] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2011] [Accepted: 02/26/2012] [Indexed: 12/12/2022] Open
Abstract
The most common neuromuscular manifestation of West Nile virus (WNV) infection is a poliomyelitis syndrome with asymmetric paralysis variably involving one (monoparesis) to four limbs (quadriparesis), with or without brainstem involvement and respiratory failure. This syndrome of acute flaccid paralysis may occur without overt fever or meningoencephalitis. Although involvement of anterior horn cells in the spinal cord and motor neurons in the brainstem are the major sites of pathology responsible for neuromuscular signs, inflammation also may involve skeletal or cardiac muscle (myositis, myocarditis), motor axons (polyradiculitis), and peripheral nerves [Guillain–Barré syndrome (GBS), brachial plexopathy]. In addition, involvement of spinal sympathetic neurons and ganglia provides an explanation for autonomic instability seen in some patients. Many patients also experience prolonged subjective generalized weakness and disabling fatigue. Despite recent evidence that WNV may persist long-term in the central nervous system or periphery in animals, the evidence in humans is controversial. WNV persistence would be of great concern in immunosuppressed patients or in those with prolonged or recurrent symptoms. Support for the contention that WNV can lead to autoimmune disease arises from reports of patients presenting with various neuromuscular diseases that presumably involve autoimmune mechanisms (GBS, other demyelinating neuropathies, myasthenia gravis, brachial plexopathies, stiff-person syndrome, and delayed or recurrent symptoms). Although there is no specific treatment or vaccine currently approved in humans, and the standard remains supportive care, drugs that can alter the cascade of immunobiochemical events leading to neuronal death may be potentially useful (high-dose corticosteroids, interferon preparations, and intravenous immune globulin containing WNV-specific antibodies). Human experience with these agents seems promising based on anecdotal reports.
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Affiliation(s)
- A Arturo Leis
- Center for Neuroscience and Neurological Recovery, Methodist Rehabilitation Center Jackson, MS, USA
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91
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Lim SM, Koraka P, Osterhaus AD, Martina BE. West Nile virus: immunity and pathogenesis. Viruses 2011; 3:811-28. [PMID: 21994755 PMCID: PMC3185772 DOI: 10.3390/v3060811] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2011] [Revised: 05/26/2011] [Accepted: 05/27/2011] [Indexed: 11/17/2022] Open
Abstract
West Nile virus (WNV) is a neurotropic, arthropod-borne flavivirus that is maintained in an enzootic cycle between mosquitoes and birds, but can also infect and cause disease in horses and humans. WNV is endemic in parts of Africa, Europe, the Middle East, and Asia, and since 1999 has spread to North America, Mexico, South America, and the Caribbean. WNV infects the central nervous system (CNS) and can cause severe disease in a small minority of infected humans, mostly immunocompromised or the elderly. This review discusses some of the mechanisms by which the immune system can limit dissemination of WNV infection and elaborates on the mechanisms involved in pathogenesis. Reasons for susceptibility to WNV-associated neuroinvasive disease in less than 1% of cases remain unexplained, but one favored hypothesis is that the involvement of the CNS is associated with a weak immune response allowing robust WNV replication in the periphery and spread of the virus to the CNS.
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Affiliation(s)
- Stephanie M. Lim
- Department of Virology, Erasmus MC, P.O. Box 2040, 3000 CA Rotterdam, The Netherlands; E-Mails: (S.M.L.); (P.K.); (A.D.M.E.O.)
| | - Penelope Koraka
- Department of Virology, Erasmus MC, P.O. Box 2040, 3000 CA Rotterdam, The Netherlands; E-Mails: (S.M.L.); (P.K.); (A.D.M.E.O.)
| | - Albert D.M.E. Osterhaus
- Department of Virology, Erasmus MC, P.O. Box 2040, 3000 CA Rotterdam, The Netherlands; E-Mails: (S.M.L.); (P.K.); (A.D.M.E.O.)
| | - Byron E.E. Martina
- Department of Virology, Erasmus MC, P.O. Box 2040, 3000 CA Rotterdam, The Netherlands; E-Mails: (S.M.L.); (P.K.); (A.D.M.E.O.)
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Smeraski CA, Siddharthan V, Morrey JD. Treatment of spatial memory impairment in hamsters infected with West Nile virus using a humanized monoclonal antibody MGAWN1. Antiviral Res 2011; 91:43-9. [PMID: 21554903 DOI: 10.1016/j.antiviral.2011.04.011] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2011] [Revised: 04/18/2011] [Accepted: 04/22/2011] [Indexed: 01/23/2023]
Abstract
In addition to functional disorders of paresis, paralysis, and cardiopulmonary complications, subsets of West Nile virus (WNV) patients may also experience neurocognitive deficits and memory disturbances. A previous hamster study has also demonstrated spatial memory impairment using the Morris water maze (MWM) paradigm. The discovery of an efficacious therapeutic antibody MGAWN1 from pre-clinical rodent studies raises the possibility of preventing or treating WNV-induced memory deficits. In the current study, hamsters were treated intraperitoneally (i.p.) with 32 mg/kg of MGAWN1 at 4.5 days after subcutaneously (s.c.) challenging with WNV. As expected, MGAWN1 prevented mortality, weight loss, and improved food consumption of WNV-infected hamsters. The criteria for entry of surviving hamsters into the study were that they needed to have normal motor function (forelimb grip strength, beam walking) and normal spatial reference memory in the MWM probe task. Twenty-eight days after the acute phase of the disease had passed, MGAWN1- and saline-treated infected hamsters were again trained in the MWM. Spatial memory was evaluated 48 h after this training in which the hamsters searched for the location where a submerged escape platform had been positioned. Only 56% of infected hamsters treated with saline spent more time in the correct quadrant than the other three quadrants, as compared to 92% of MGAWN1-treated hamsters (P⩽0.05). Overall these studies support the possibility that WNV can cause spatial memory impairment and that therapeutic intervention may be considered.
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Affiliation(s)
- Cynthia A Smeraski
- Department of Biomedical Sciences, Animal Reproduction and Biotechnology Laboratory, Colorado State University, Fort Collins, USA
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Verma S, Kumar M, Nerurkar VR. Cyclooxygenase-2 inhibitor blocks the production of West Nile virus-induced neuroinflammatory markers in astrocytes. J Gen Virol 2010; 92:507-15. [PMID: 21106803 PMCID: PMC3081232 DOI: 10.1099/vir.0.026716-0] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Inflammatory immune responses triggered initially to clear West Nile virus (WNV) infection later become detrimental and contribute to the pathological processes such as blood–brain barrier (BBB) disruption and neuronal death, thus complicating WNV-associated encephalitis (WNVE). It has been demonstrated previously that WNV infection in astrocytes results in induction of multiple matrix metalloproteinases (MMPs), which mediate BBB disruption. Cyclooxygenase (COX) enzymes and their product, prostaglandin E2 (PGE2), modulate neuroinflammation and regulate the production of multiple inflammatory molecules including MMPs. Therefore, this study determined and characterized the pathophysiological consequences of the expression of COX enzymes in human brain cortical astrocytes (HBCAs) following WNV infection. Whilst COX-1 mRNA expression did not change, WNV infection significantly induced RNA and protein expression of COX-2 in HBCAs. Similarly, PGE2 production was also enhanced significantly in infected HBCAs and was blocked in the presence of the COX-2-specific inhibitor NS-398, thus suggesting that COX-2, and not COX-1, was the source of the increased PGE2. Treatment of infected HBCAs with NS-398 attenuated the expression of MMP-1, -3 and -9 in a dose-dependent manner. Similarly, expression of interleukin-1β, -6 and -8, which were markedly elevated in infected HBCAs, exhibited a significant reduction in their levels in the presence of NS-398. These results provide direct evidence that WNV-induced COX-2/PGE2 is involved in modulating the expression of multiple neuroinflammatory mediators, thereby directly linking COX-2 with WNV disease pathogenesis. The ability of COX-2 inhibitors to modulate WNV-induced COX-2 and PGE2 signalling warrants further investigation in an animal model as a potential approach for clinical management of neuroinflammation associated with WNVE.
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Affiliation(s)
- Saguna Verma
- Retrovirology Research Laboratory, Department of Tropical Medicine, Medical Microbiology and Pharmacology, John A. Burns School of Medicine, University of Hawaii at Manoa, Honolulu, HI 96813, USA.
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