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29 pages, 17237 KiB

Open AccessArticle

Reactive Oxygen Species Are Key Mediators of Demyelination in Canine Distemper Leukoencephalitis but not in Theiler’s Murine Encephalomyelitis

by Friederike Attig, Ingo Spitzbarth, Arno Kalkuhl, Ulrich Deschl, Christina Puff, Wolfgang Baumgärtner and Reiner Ulrich

Int. J. Mol. Sci. 2019, 20(13), 3217; https://doi.org/10.3390/ijms20133217 - 30 Jun 2019

Cited by 9 | Viewed by 3180

Abstract

(1) Background: Canine distemper virus (CDV)-induced demyelinating leukoencephalitis (CDV-DL) in dogs and Theiler’s murine encephalomyelitis (TME) virus (TMEV)-induced demyelinating leukomyelitis (TMEV-DL) are virus-induced demyelinating conditions mimicking Multiple Sclerosis (MS). Reactive oxygen species (ROS) can induce the degradation of lipids and nucleic acids to [...] Read more.

(1) Background: Canine distemper virus (CDV)-induced demyelinating leukoencephalitis (CDV-DL) in dogs and Theiler’s murine encephalomyelitis (TME) virus (TMEV)-induced demyelinating leukomyelitis (TMEV-DL) are virus-induced demyelinating conditions mimicking Multiple Sclerosis (MS). Reactive oxygen species (ROS) can induce the degradation of lipids and nucleic acids to characteristic metabolites such as oxidized lipids, malondialdehyde, and 8-hydroxyguanosine. The hypothesis of this study is that ROS are key effector molecules in the pathogenesis of myelin membrane breakdown in CDV-DL and TMEV-DL. (2) Methods: ROS metabolites and antioxidative enzymes were assessed using immunofluorescence in cerebellar lesions of naturally CDV-infected dogs and spinal cord tissue of TMEV-infected mice. The transcription of selected genes involved in ROS generation and detoxification was analyzed using gene-expression microarrays in CDV-DL and TMEV-DL. (3) Results: Immunofluorescence revealed increased amounts of oxidized lipids, malondialdehyde, and 8-hydroxyguanosine in CDV-DL while TMEV-infected mice did not reveal marked changes. In contrast, microarray-analysis showed an upregulated gene expression associated with ROS generation in both diseases. (4) Conclusion: In summary, the present study demonstrates a similar upregulation of gene-expression of ROS generation in CDV-DL and TMEV-DL. However, immunofluorescence revealed increased accumulation of ROS metabolites exclusively in CDV-DL. These results suggest differences in the pathogenesis of demyelination in these two animal models. Full article

(This article belongs to the Special Issue Neuroinfectiology: Molecular and Cellular Mechanisms of Neurotropic Virus Infection)

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14 pages, 5051 KiB

Open AccessArticle

Delayed Astrogliosis Associated with Reduced M1 Microglia Activation in Matrix Metalloproteinase 12 Knockout Mice during Theiler’s Murine Encephalomyelitis

by Florian Hansmann, Ning Zhang, Vanessa Herder, Eva Leitzen and Wolfgang Baumgärtner

Int. J. Mol. Sci. 2019, 20(7), 1702; https://doi.org/10.3390/ijms20071702 - 05 Apr 2019

Cited by 12 | Viewed by 3430

Abstract

Theiler’s murine encephalomyelitis (TME) represents a versatile animal model for studying the pathogenesis of demyelinating diseases such as multiple sclerosis. Hallmarks of TME are demyelination, astrogliosis, as well as inflammation. Previous studies showed that matrix metalloproteinase 12 knockout (Mmp12^−/−) mice [...] Read more.

Theiler’s murine encephalomyelitis (TME) represents a versatile animal model for studying the pathogenesis of demyelinating diseases such as multiple sclerosis. Hallmarks of TME are demyelination, astrogliosis, as well as inflammation. Previous studies showed that matrix metalloproteinase 12 knockout (Mmp12^−/−) mice display an ameliorated clinical course associated with reduced demyelination. The present study aims to elucidate the impact of MMP12 deficiency in TME with special emphasis on astrogliosis, macrophages infiltrating the central nervous system (CNS), and the phenotype of microglia/macrophages (M1 or M2). SJL wild-type and Mmp12^−/− mice were infected with TME virus (TMEV) or vehicle (mock) and euthanized at 28 and 98 days post infection (dpi). Immunohistochemistry or immunofluorescence of cervical and thoracic spinal cord for detecting glial fibrillary acidic protein (GFAP), ionized calcium-binding adaptor molecule 1 (Iba1), chemokine receptor 2 (CCR2), CD107b, CD16/32, and arginase I was performed and quantitatively evaluated. Statistical analyses included the Kruskal–Wallis test followed by Mann–Whitney U post hoc tests. TMEV-infected Mmp12^−/− mice showed transiently reduced astrogliosis in association with a strong trend (p = 0.051) for a reduced density of activated/reactive microglia/macrophages compared with wild-type mice at 28 dpi. As astrocytes are an important source of cytokine production, including proinflammatory cytokines triggering or activating phagocytes, the origin of intralesional microglia/macrophages as well as their phenotype were determined. Only few phagocytes in wild-type and Mmp12^−/− mice expressed CCR2, indicating that the majority of phagocytes are represented by microglia. In parallel to the reduced density of activated/reactive microglia at 98 dpi, TMEV-infected Mmp12^−/− showed a trend (p = 0.073) for a reduced density of M1 (CD16/32- and CD107b-positive) microglia, while no difference regarding the density of M2 (arginase I- and CD107b-positive) cells was observed. However, a dominance of M1 cells was detected in the spinal cord of TMEV-infected mice at all time points. Reduced astrogliosis in Mmp12^−/− mice was associated with a reduced density of activated/reactive microglia and a trend for a reduced density of M1 cells. This indicates that MMP12 plays an important role in microglia activation, polarization, and migration as well as astrogliosis and microglia/astrocyte interaction. Full article

(This article belongs to the Special Issue Neuroinfectiology: Molecular and Cellular Mechanisms of Neurotropic Virus Infection)

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22 pages, 5641 KiB

Open AccessArticle

Interferon-Stimulated Genes—Mediators of the Innate Immune Response during Canine Distemper Virus Infection

by Daniela Klotz and Ingo Gerhauser

Int. J. Mol. Sci. 2019, 20(7), 1620; https://doi.org/10.3390/ijms20071620 - 01 Apr 2019

Cited by 15 | Viewed by 6549

Abstract

The demyelinating canine distemper virus (CDV)-leukoencephalitis represents a translational animal model for multiple sclerosis. The present study investigated the expression of type I interferon (IFN-I) pathway members in CDV-induced cerebellar lesions to gain an insight into their role in lesion development. Gene expression [...] Read more.

The demyelinating canine distemper virus (CDV)-leukoencephalitis represents a translational animal model for multiple sclerosis. The present study investigated the expression of type I interferon (IFN-I) pathway members in CDV-induced cerebellar lesions to gain an insight into their role in lesion development. Gene expression of 110 manually selected genes in acute, subacute and chronic lesions was analyzed using pre-existing microarray data. Interferon regulatory factor (IRF) 3, IRF7, signal transducer and activator of transcription (STAT) 1, STAT2, MX protein, protein kinase R (PKR), 2′-5′-oligoadenylate synthetase (OAS) 1 and interferon-stimulated gene (ISG) 15 expression were also evaluated using immunohistochemistry. Cellular origin of STAT1, STAT2, MX and PKR were determined using immunofluorescence. CDV infection caused an increased expression of the antiviral effector proteins MX, PKR, OAS1 and ISG15, which probably contributed to a restricted viral replication, particularly in neurons and oligodendrocytes. This increase might be partly mediated by IRF-dependent pathways due to the lack of changes in IFN-I levels and absence of STAT2 in astrocytes. Nevertheless, activated microglia/macrophages showed a strong expression of STAT1, STAT2 and MX proteins in later stages of the disease, indicating a strong activation of the IFN-I signaling cascade, which might be involved in the aggravation of bystander demyelination. Full article

(This article belongs to the Special Issue Neuroinfectiology: Molecular and Cellular Mechanisms of Neurotropic Virus Infection)

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19 pages, 3349 KiB

Open AccessArticle

Intranasal Borna Disease Virus (BoDV-1) Infection: Insights into Initial Steps and Potential Contagiosity

by Alexandra Kupke, Sabrina Becker, Konstantin Wewetzer, Barbara Ahlemeyer, Markus Eickmann and Christiane Herden

Int. J. Mol. Sci. 2019, 20(6), 1318; https://doi.org/10.3390/ijms20061318 - 15 Mar 2019

Cited by 18 | Viewed by 3580

Abstract

Mammalian Bornavirus (BoDV-1) typically causes a fatal neurologic disorder in horses and sheep, and was recently shown to cause fatal encephalitis in humans with and without transplant reception. It has been suggested that BoDV-1 enters the central nervous system (CNS) via the olfactory [...] Read more.

Mammalian Bornavirus (BoDV-1) typically causes a fatal neurologic disorder in horses and sheep, and was recently shown to cause fatal encephalitis in humans with and without transplant reception. It has been suggested that BoDV-1 enters the central nervous system (CNS) via the olfactory pathway. However, (I) susceptible cell types that replicate the virus for successful spread, and (II) the role of olfactory ensheathing cells (OECs), remained unclear. To address this, we studied the intranasal infection of adult rats with BoDV-1 in vivo and in vitro, using olfactory mucosal (OM) cell cultures and the cultures of purified OECs. Strikingly, in vitro and in vivo, viral antigen and mRNA were present from four days post infection (dpi) onwards in the olfactory receptor neurons (ORNs), but also in all other cell types of the OM, and constantly in the OECs. In contrast, in vivo, BoDV-1 genomic RNA was only detectable in adult and juvenile ORNs, nerve fibers, and in OECs from 7 dpi on. In vitro, the rate of infection of OECs was significantly higher than that of the OM cells, pointing to a crucial role of OECs for infection via the olfactory pathway. Thus, this study provides important insights into the transmission of neurotropic viral infections with a zoonotic potential. Full article

(This article belongs to the Special Issue Neuroinfectiology: Molecular and Cellular Mechanisms of Neurotropic Virus Infection)

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17 pages, 2657 KiB

Open AccessArticle

Cryopreservation of Canine Primary Dorsal Root Ganglion Neurons and Its Impact upon Susceptibility to Paramyxovirus Infection

by Sarah Schwarz, Ingo Spitzbarth, Wolfgang Baumgärtner and Annika Lehmbecker

Int. J. Mol. Sci. 2019, 20(5), 1058; https://doi.org/10.3390/ijms20051058 - 28 Feb 2019

Cited by 6 | Viewed by 4065

Abstract

Canine dorsal root ganglion (DRG) neurons, isolated post mortem from adult dogs, could provide a promising tool to study neuropathogenesis of neurotropic virus infections with a non-rodent host spectrum. However, access to canine DRG is limited due to lack of donor tissue and [...] Read more.

Canine dorsal root ganglion (DRG) neurons, isolated post mortem from adult dogs, could provide a promising tool to study neuropathogenesis of neurotropic virus infections with a non-rodent host spectrum. However, access to canine DRG is limited due to lack of donor tissue and the cryopreservation of DRG neurons would greatly facilitate experiments. The present study aimed (i) to establish canine DRG neurons as an in vitro model for canine distemper virus (CDV) infection; and (ii) to determine whether DRG neurons are cryopreservable and remain infectable with CDV. Neurons were characterized morphologically and phenotypically by light microscopy, immunofluorescence, and functionally, by studying their neurite outgrowth and infectability with CDV. Cryopreserved canine DRG neurons remained in culture for at least 12 days. Furthermore, both non-cryopreserved and cryopreserved DRG neurons were susceptible to infection with two different strains of CDV, albeit only one of the two strains (CDV R252) provided sufficient absolute numbers of infected neurons. However, cryopreserved DRG neurons showed reduced cell yield, neurite outgrowth, neurite branching, and soma size and reduced susceptibility to CDV infection. In conclusion, canine primary DRG neurons represent a suitable tool for investigations upon the pathogenesis of neuronal CDV infection. Moreover, despite certain limitations, cryopreserved canine DRG neurons generally provide a useful and practicable alternative to address questions regarding virus tropism and neuropathogenesis. Full article

(This article belongs to the Special Issue Neuroinfectiology: Molecular and Cellular Mechanisms of Neurotropic Virus Infection)

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17 pages, 3624 KiB

Open AccessArticle

Comparison of Reported Spinal Cord Lesions in Progressive Multiple Sclerosis with Theiler’s Murine Encephalomyelitis Virus Induced Demyelinating Disease

by Eva Leitzen, Wen Jin, Vanessa Herder, Andreas Beineke, Suliman Ahmed Elmarabet, Wolfgang Baumgärtner and Florian Hansmann

Int. J. Mol. Sci. 2019, 20(4), 989; https://doi.org/10.3390/ijms20040989 - 25 Feb 2019

Cited by 9 | Viewed by 4085

Abstract

Background: Spinal cord (SC) lesions in Theiler’s murine encephalomyelitis virus induced demyelinating disease (TMEV-IDD) resemble important features of brain lesions in progressive multiple sclerosis (MS) including inflammation, demyelination, and axonal damage. The aim of the present study was a comparison of SC lesions [...] Read more.

Background: Spinal cord (SC) lesions in Theiler’s murine encephalomyelitis virus induced demyelinating disease (TMEV-IDD) resemble important features of brain lesions in progressive multiple sclerosis (MS) including inflammation, demyelination, and axonal damage. The aim of the present study was a comparison of SC lesions in MS and TMEV-IDD focusing on spatial and temporal distribution of demyelination, inflammation, SC atrophy (SCA), and axonal degeneration/loss in major descending motor pathways. Methods: TMEV and mock-infected mice were investigated clinically once a week. SC tissue was collected at 42, 98, 147, and 196 days post infection, and investigated using hematoxylin and eosin (HE) staining, immunohistochemistry targeting myelin basic protein (demyelination), Mac3 (microglia/macrophages), phosphorylated neurofilaments (axonal damage) and transmission electron microscopy. Results: Demyelination prevailed in SC white matter in TMEV-IDD, contrasting a predominant gray matter involvement in MS. TMEV-infected mice revealed a significant loss of axons similar to MS. Ultrastructural analysis in TMEV-IDD revealed denuded axons, degenerative myelin changes, axonal degeneration, as well as remyelination. SCA is a consistent finding in the SC of MS patients and was also detected at a late time point in TMEV-IDD. Conclusion: This comparative study further indicates the suitability of TMEV-IDD as animal model also for the investigation of progressive SC lesions in MS. Full article

(This article belongs to the Special Issue Neuroinfectiology: Molecular and Cellular Mechanisms of Neurotropic Virus Infection)

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13 pages, 1581 KiB

Open AccessArticle

Identification of Cerebrospinal Fluid Metabolites as Biomarkers for Enterovirus Meningitis

by Dominica Ratuszny, Kurt-Wolfram Sühs, Natalia Novoselova, Maike Kuhn, Volkhard Kaever, Thomas Skripuletz, Frank Pessler and Martin Stangel

Int. J. Mol. Sci. 2019, 20(2), 337; https://doi.org/10.3390/ijms20020337 - 15 Jan 2019

Cited by 12 | Viewed by 3592

Abstract

Enteroviruses are among the most common causes of viral meningitis. Enteroviral meningitis continues to represent diagnostic challenges, as cerebrospinal fluid (CSF) cell numbers (a well validated diagnostic screening tool) may be normal in up to 15% of patients. We aimed to identify potential [...] Read more.

Enteroviruses are among the most common causes of viral meningitis. Enteroviral meningitis continues to represent diagnostic challenges, as cerebrospinal fluid (CSF) cell numbers (a well validated diagnostic screening tool) may be normal in up to 15% of patients. We aimed to identify potential CSF biomarkers for enteroviral meningitis, particularly for cases with normal CSF cell count. Using targeted liquid chromatography-mass spectrometry, we determined metabolite profiles from patients with enteroviral meningitis (n = 10), and subdivided them into those with elevated (n = 5) and normal (n = 5) CSF leukocyte counts. Non-inflamed CSF samples from patients with Bell’s palsy and normal pressure hydrocephalus (n = 19) were used as controls. Analysis of 91 metabolites revealed considerable metabolic reprogramming in the meningitis samples. It identified phosphatidylcholine PC.ae.C36.3, asparagine, and glycine as an accurate (AUC, 0.92) combined classifier for enterovirus meningitis overall, and kynurenine as a perfect biomarker for enteroviral meningitis with an increased CSF cell count (AUC, 1.0). Remarkably, PC.ae.C36.3 alone emerged as a single accurate (AUC, 0.87) biomarker for enteroviral meningitis with normal cell count, and a combined classifier comprising PC.ae.C36.3, PC.ae.C36.5, and PC.ae.C38.5 achieved nearly perfect classification (AUC, 0.99). Taken together, this analysis reveals the potential of CSF metabolites as additional diagnostic tools for enteroviral meningitis, and likely other central nervous system (CNS) infections. Full article

(This article belongs to the Special Issue Neuroinfectiology: Molecular and Cellular Mechanisms of Neurotropic Virus Infection)

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Review

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34 pages, 2776 KiB

Open AccessReview

Facets of Theiler’s Murine Encephalomyelitis Virus-Induced Diseases: An Update

by Ingo Gerhauser, Florian Hansmann, Malgorzata Ciurkiewicz, Wolfgang Löscher and Andreas Beineke

Int. J. Mol. Sci. 2019, 20(2), 448; https://doi.org/10.3390/ijms20020448 - 21 Jan 2019

Cited by 47 | Viewed by 6886

Abstract

Theiler’s murine encephalomyelitis virus (TMEV), a naturally occurring, enteric pathogen of mice is a Cardiovirus of the Picornaviridae family. Low neurovirulent TMEV strains such as BeAn cause a severe demyelinating disease in susceptible SJL mice following intracerebral infection. Furthermore, TMEV infections of C57BL/6 [...] Read more.

Theiler’s murine encephalomyelitis virus (TMEV), a naturally occurring, enteric pathogen of mice is a Cardiovirus of the Picornaviridae family. Low neurovirulent TMEV strains such as BeAn cause a severe demyelinating disease in susceptible SJL mice following intracerebral infection. Furthermore, TMEV infections of C57BL/6 mice cause acute polioencephalitis initiating a process of epileptogenesis that results in spontaneous recurrent epileptic seizures in approximately 50% of affected mice. Moreover, C3H mice develop cardiac lesions after an intraperitoneal high-dose application of TMEV. Consequently, TMEV-induced diseases are widely used as animal models for multiple sclerosis, epilepsy, and myocarditis. The present review summarizes morphological lesions and pathogenic mechanisms triggered by TMEV with a special focus on the development of hippocampal degeneration and seizures in C57BL/6 mice as well as demyelination in the spinal cord in SJL mice. Furthermore, a detailed description of innate and adaptive immune responses is given. TMEV studies provide novel insights into the complexity of organ- and mouse strain-specific immunopathology and help to identify factors critical for virus persistence. Full article

(This article belongs to the Special Issue Neuroinfectiology: Molecular and Cellular Mechanisms of Neurotropic Virus Infection)

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