Mouse Model Of Multiple Sclerosis Research Articles

Diphtheria toxin-derived, anti-PD-1 immunotoxin, a potent and practical tool to selectively deplete PD-1+ cells.

Programmed death-1 (PD-1), an immune checkpoint receptor, is expressed on activated lymphocytes, macrophages, and some types of tumor cells. While PD-1+ cells have been implicated in outcomes of cancer immunity, autoimmunity, and chronic infections, the exact roles of these cells in various physiological and pathological processes remain elusive. Molecules that target and deplete PD-1+ cells would be instrumental in defining the roles unambiguously. Previously, an immunotoxin has been generated for the depletion of PD-1+ cells though its usage is impeded by its low production yield. Thus, a more practical molecular tool is desired to deplete PD-1+ cells and to examine functions of these cells. We designed and generated a novel anti-PD1 diphtheria immunotoxin, termed PD-1 DIT, targeting PD-1+ cells. PD-1 DIT is comprised of two single chain variable fragments (scFv) derived from an anti-PD-1 antibody, coupled with the catalytic and translocation domains of the diphtheria toxin. PD-1 DIT was produced using a yeast expression system that has been engineered to efficiently produce protein toxins. The yield of PD-1 DIT reached 1~2 mg/L culture, which is ten times higher than the previously reported immunotoxin. Flow cytometry and confocal microscopy analyses confirmed that PD-1 DIT specifically binds to and enters PD-1+ cells. The binding avidities between PD-1 DIT and two PD-1+ cell lines are approximately 25 nM. Moreover, PD-1 DIT demonstrated potent cytotoxicity towards PD-1+ cells, with an EC50 value of 1 nM. In vivo experiments further showed that PD-1 DIT effectively depleted PD-1+ cells and enabled mice inoculated with PD-1+ tumor cells to survive throughout the study. Our findings using PD-1 DIT revealed the critical role of pancreatic PD-1+ T cells in the development of type-1 diabetes (T1D). Additionally, we observed that PD-1 DIT treatment ameliorated relapsing-remitting experimental autoimmune encephalomyelitis (RR-EAE), a mouse model of relapsing-remitting multiple sclerosis (RR-MS). Lastly, we did not observe significant hepatotoxicity in mice treated with PD-1 DIT, which had been reported for other immunotoxins derived from the diphtheria toxin. With its remarkable selective and potent cytotoxicity towards PD-1+ cells, coupled with its high production yield, PD-1 DIT emerges as a powerful biotechnological tool for elucidating the physiological roles of PD-1+ cells. Furthermore, the potential of PD-1 DIT to be developed into a novel therapeutic agent becomes evident. This article is protected by copyright. All rights reserved.

Effect of Siponimod on Brain and Spinal Cord Imaging Markers of Neurodegeneration in the Theiler's Murine Encephalomyelitis Virus Model of Demyelination.

Siponimod (Sp) is a Sphingosine 1-phosphate (S1P) receptor modulator, and it suppresses S1P- mediated autoimmune lymphocyte transport and inflammation. Theiler's murine encephalomyelitis virus (TMEV) infection mouse model of multiple sclerosis (MS) exhibits inflammation-driven acute and chronic phases, spinal cord lesions, brain and spinal cord atrophy, and white matter injury. The objective of the study was to investigate whether Sp treatment could attenuate inflammation-induced pathology in the TMEV model by inhibiting microglial activation and preventing the atrophy of central nervous tissue associated with neurodegeneration. Clinical disability score (CDS), body weight (BW), and rotarod retention time measures were used to assess Sp's impact on neurodegeneration and disease progression in 4 study groups of 102 animals, including 44 Sp-treated (SpT), 44 vehicle-treated, 6 saline-injected, and 8 age-matched healthy controls (HC). Next, 58 (22 SpT, 22 vehicle, 6 saline injected, and 8 HC) out of the 102 animals were further evaluated to assess the effect of Sp on brain region-specific and spinal cord volume changes, as well as microglial activation. Sp increased CDS and decreased BW and rotarod retention time in TMEV mice, but did not significantly affect most brain region volumes, except for lateral ventricle volume. Sp suppressed ventricular enlargement, suggesting reduced TMEV-induced inflammation in LV. No significant differences in spine volume changes were observed between Sp- and vehicle-treated animals, but there were differences between HC and TMEV groups, indicating TMEV-induced inflammation contributed to increased spine volume. Spine histology revealed no significant microglial density differences between groups in gray matter, but HC animals had higher type 1 morphology and lower type 2 morphology percentages in gray and white matter regions. This suggests that Sp did not significantly affect microglial density but may have modulated neuroinflammation in the spinal cord. Sp may have some effects on neuroinflammation and ventricular enlargement. However, it did not demonstrate a significant impact on neurodegeneration, spinal volume, or lesion volume in the TMEV mouse model. Further investigation is required to fully understand Sp's effect on microglial activation and its relevance to the pathophysiology of MS. The differences between the current study and previous research using other MS models, such as EAE, highlight the differences in pathological processes in these two disease models.

Stat1 is an inducible transcriptional repressor of neural stem cells self-renewal program during neuroinflammation.

A central issue in regenerative medicine is understanding the mechanisms that regulate the self-renewal of endogenous stem cells in response to injury and disease. Interferons increase hematopoietic stem cells during infection by activating STAT1, but the mechanisms by which STAT1 regulates intrinsic programs in neural stem cells (NSCs) during neuroinflammation is less known. Here we explored the role of STAT1 on NSC self-renewal. We show that overexpressing Stat1 in NSCs derived from the subventricular zone (SVZ) decreases NSC self-renewal capacity while Stat1 deletion increases NSC self-renewal, neurogenesis, and oligodendrogenesis in isolated NSCs. Importantly, we find upregulation of STAT1 in NSCs in a mouse model of multiple sclerosis (MS) and an increase in pathological T cells expressing IFN-γ rather than interleukin 17 (IL-17) in the cerebrospinal fluid of affected mice. We find IFN-γ is superior to IL-17 in reducing proliferation and precipitating an abnormal NSC phenotype featuring increased STAT1 phosphorylation and Stat1 and p16ink4a gene expression. Notably, Stat1-/- NSCs were resistant to the effect of IFN-γ. Lastly, we identified a Stat1-dependent gene expression profile associated with an increase in the Sox9 transcription factor, a regulator of self-renewal. Stat1 binds and transcriptionally represses Sox9 in a transcriptional luciferase assay. We conclude that Stat1 serves as an inducible checkpoint for NSC self-renewal that is upregulated during chronic brain inflammation leading to decreased self-renewal. As such, Stat1 may be a potential target to modulate for next generation therapies to prevent progression and loss of repair function in NSCs/neural progenitors in MS.

Proteolipid Protein-Induced Mouse Model of Multiple Sclerosis Requires B Cell-Mediated Antigen Presentation.

The pathogenic role B cells play in multiple sclerosis is underscored by the success of B cell depletion therapies. Yet, it remains unclear how B cells contribute to disease, although it is increasingly accepted that mechanisms beyond Ab production are involved. Better understanding of pathogenic interactions between B cells and autoreactive CD4 T cells will be critical for novel therapeutics. To focus the investigation on B cell:CD4 T cell interactions invivo and invitro, we previously developed a B cell-dependent, Ab-independent experimental autoimmune encephalomyelitis (EAE) mouse model driven by a peptide encompassing the extracellular domains of myelin proteolipid protein (PLPECD). In this study, we demonstrate that B cell depletion significantly inhibited PLPECD-induced EAE disease, blunted PLPECD-elicited delayed-type hypersensitivity reactions invivo, and reduced CD4 T cell activation, proliferation, and proinflammatory cytokine production. Further, PLPECD-reactive CD4 T cells sourced from B cell-depleted donor mice failed to transfer EAE to naive recipients. Importantly, we identified B cell-mediated Ag presentation as the critical mechanism explaining B cell dependence in PLPECD-induced EAE, where bone marrow chimeric mice harboring a B cell-restricted MHC class II deficiency failed to develop EAE. B cells were ultimately observed to restimulate significantly higher Ag-specific proliferation from PLP178-191-reactive CD4 T cells compared with dendritic cells when provided PLPECD peptide in head-to-head cultures. We therefore conclude that PLPECD-induced EAE features a required pathogenic B cell-mediated Ag presentation function, providing for investigable B cell:CD4 T cell interactions in the context of autoimmune demyelinating disease.

Retraction Note: Protective effects of melatonin against mitochondrial injury in a mouse model of multiple sclerosis.

Retraction Note: Protective effects of melatonin against mitochondrial injury in a mouse model of multiple sclerosis.

Histopatological parameters of the spinal cord in different phases of experimental autoimmune encephalomyelitis. A mouse model of multiple sclerosis examined by classical stainings combined with immunohistochemistry.

Multiple sclerosis (MS) and its animal model, experimental autoimmune encephalomyelitis (EAE) are characterized by three main histopathological parameters: inflammation, demyelination and axonal damage. In this study, these parameters were assessed in spinal cords of mice in the successive phases of EAE by quantitative histology and immunohistochemistry. The number of inflammatory lesions, the intensity of inflammation and expression of CD45 corresponded with the severity of clinical symptoms: they increased from the onset phase to the peak phase of the disease and subsided in the chronic phase. Demyelination increased in the peak phase and did not change in the chronic phase of EAE, although axonal damage gradually increased from the onset phase to the chronic phase, suggesting compensatory hypermyelination in that phase. The markers of myelin and axonal injury: myelin basic protein (MBP) and beta amyloid precursor protein (β-APP) showed changes (decrease and increase, respectively) of expression parallel to changes in demyelination and axonal damage. Results of this study indicate that although inflammation intensity subsides in the chronic phase of EAE, the neurodestructive processes: demyelination and axonal damage continue in that phase.

The complexities of investigating mitochondria dynamics in multiple sclerosis and mouse models of MS.

Multiple sclerosis (MS) is a demyelinating, degenerating disorder of the central nervous system (CNS) that is accompanied by mitochondria energy production failure. A loss of myelin paired with a deficit in energy production can contribute to further neurodegeneration and disability in patients in MS. Mitochondria are essential organelles that produce adenosine triphosphate (ATP) via oxidative phosphorylation in all cells in the CNS, including neurons, oligodendrocytes, astrocytes, and immune cells. In the context of demyelinating diseases, mitochondria have been shown to alter their morphology and undergo an initial increase in metabolic demand. This is followed by mitochondrial respiratory chain deficiency and abnormalities in mitochondrial transport that contribute to progressive neurodegeneration and irreversible disability. The current methodologies to study mitochondria are limiting and are capable of providing only a partial snapshot of the true mitochondria activity at a particular timepoint during disease. Mitochondrial functional studies are mostly performed in cell culture or whole brain tissue, which prevents understanding of mitochondrial pathology in distinct cell types in vivo. A true understanding of cell-specific mitochondrial pathophysiology of MS in mouse models is required. Cell-specific mitochondria morphology, mitochondria motility, and ATP production studies in animal models of MS will help us understand the role of mitochondria in the normal and diseased CNS. In this review, we present currently used methods to investigate mitochondria function in MS mouse models and discuss the current advantages and caveats with using each technique. In addition, we present recently developed mitochondria transgenic mouse lines expressing Cre under the control of CNS specific promoters to relate mitochondria to disease in vivo.

Genetic deletion of c-Jun amino-terminal kinase 3 (JNK3) modestly increases disease severity in a mouse model of multiple sclerosis

The c-Jun amino terminal kinases (JNKs) regulate transcription, and studies suggest they contribute to neuropathology in the EAE model of MS. To examine the role of the JNK3 isoform, we compared EAE in JNK3 null mice to wild type (WT) littermates. Although disease severity was similar in female mice, in male JNK3 null mice the day of onset and time to reach 100% incidence occurred sooner, and disease severity was increased. While glial activation in spinal cord was similar, white matter lesions were increased in JNK3 null mice. These results suggest JNK3 normally limits EAE disease in a sex-dependent manner.

The small molecule Erk1/2 signaling pathway inhibitor PD98059 improves DNA repair in an experimental autoimmune encephalomyelitis SJL/J mouse model of multiple sclerosis.

Multiple sclerosis (MS) is a demyelinating disorder in which the myelin sheath covering the central nervous system axons is damaged or lost, disrupting action potential conduction and leading to various neurological complications. The pathogenesis of MS remains unclear, and no effective therapies are currently available. MS is triggered by environmental factors in genetically susceptible individuals. DNA damage and DNA repair failure have been proposed as MS genetic risk factors; however, inconsistent evidence has been found in multiple studies. Therefore, more investigations are needed to ascertain whether DNA damage/repair is altered in this disorder. In this context, therapies that prevent DNA damage or enhance DNA repair could be effective strategies for MS treatment. The overactivation of the extracellular-signal-related kinase 1 and 2 (Erk1/2) pathway can lead to DNA damage and has been linked to MS pathogenesis. In our study, we observed substantially elevated oxidative DNA damage and slower DNA repair rates in an experimentally autoimmune encephalomyelitis animal model of MS (EAE). Moreover, statistical decreases in oxidative DNA strand breaks and faster repair rates were observed in EAE animals injected with the Erk1/2 inhibitor PD98059 (PD). Moreover, the expression of several genes associated with DNA strand breaks and repair changed in EAE mice at both the mRNA and protein levels, as revealed by the RT2 Profiler PCR array and verified by RT-PCR and protein analyses. The treatment with PD mitigated these changes and improved DNA repair gene expression. Our results demonstrate clear associations between Erk1/2 activation, DNA damage/repair, and MS pathology, and further suggest that PD therapy may be a promising adjuvant therapeutic strategy.

PET imaging of TREM1 identifies CNS-infiltrating myeloid cells in a mouse model of multiple sclerosis.

Multiple sclerosis (MS) is an immune-mediated demyelinating disease of the central nervous system (CNS) that causes substantial morbidity and diminished quality of life. Evidence highlights the central role of myeloid lineage cells in the initiation and progression of MS. However, existing imaging strategies for detecting myeloid cells in the CNS cannot distinguish between beneficial and harmful immune responses. Thus, imaging strategies that specifically identify myeloid cells and their activation states are critical for MS disease staging and monitoring of therapeutic responses. We hypothesized that positron emission tomography (PET) imaging of triggering receptor expressed on myeloid cells 1 (TREM1) could be used to monitor deleterious innate immune responses and disease progression in the experimental autoimmune encephalomyelitis (EAE) mouse model of MS. We first validated TREM1 as a specific marker of proinflammatory, CNS-infiltrating, peripheral myeloid cells in mice with EAE. We show that the 64Cu-radiolabeled TREM1 antibody-based PET tracer monitored active disease with 14- to 17-fold higher sensitivity than translocator protein 18 kDa (TSPO)-PET imaging, the established approach for detecting neuroinflammation in vivo. We illustrate the therapeutic potential of attenuating TREM1 signaling both genetically and pharmacologically in the EAE mice and show that TREM1-PET imaging detected responses to an FDA-approved MS therapy with siponimod (BAF312) in these animals. Last, we observed TREM1+ cells in clinical brain biopsy samples from two treatment-naïve patients with MS but not in healthy control brain tissue. Thus, TREM1-PET imaging has potential for aiding in the diagnosis of MS and monitoring of therapeutic responses to drug treatment.

Vitamins A and D Enhance the Expression of Ror-γ-Targeting miRNAs in a Mouse Model of Multiple Sclerosis.

Autoreactive T cells, particularly those characterized by a Th17 phenotype, exert significant influence on the pathogenesis of multiple sclerosis (MS). The present study aimed to elucidate the impact of individual and combined administration of vitamin A and D on neuroinflammation, and microRNAs (miRNAs) involved in T helper (Th)17 development, utilizing a murine model of experimental autoimmune encephalomyelitis (EAE). EAE was induced in C57BL/6 mice, and 3 days prior to immunization, intraperitoneal injections of vitamins A and D or their combination were administered. Th17 cell percentages were determined in splenocytes utilizing intracellular staining and flow cytometry. Furthermore, the expression of Ror γ-t, miR-98-5p and Let-7a-5p, was measured in both splenocytes and spinal cord tissues using RT-PCR. Treatment with vitamin A and D resulted in a reduction in both disease severity in EAE mice. Treated mice showed a decreased frequency of Th17 cells and lower expression levels of IL17 and Ror γ-t in splenocytes and spinal cord. The spinal cord tissues and splenocytes of mice treated with vitamins A, D, and combined A+D showed a significant upregulation of miR-98-5p and Let-7a-5p compared to the EAE group. Statistical analysis indicated a strong negative correlation between miR-98-5p and Let-7a-5p levels in splenocytes and Ror-t expression. Our findings indicate that the administration of vitamins A and D exerts a suppressive effect on neuroinflammation in EAE that is associated with a reduction in the differentiation of T cells into the Th17 phenotype and is mediated by the upregulation of miR-98-5p and Let-7a-5p, which target the Ror γ-t.

Bioengineered particles expand myelin-specific regulatory T cells and reverse autoreactivity in a mouse model of multiple sclerosis.

Multiple sclerosis (MS) is an autoimmune disease characterized by autoreactive immune cells damaging myelinated nerves, impairing brain function. Treatments aim for tolerance induction to reeducate the immune system to recognize myelin as "self" rather than "foreign." As peripheral immune tolerance is primarily mediated by regulatory T cells (Tregs), we developed a therapy to support Treg expansion and activity in vivo. To target, engage, and activate myelin-specific Tregs, we designed a biodegradable microparticle (MP) loaded with rapamycin and functionalized with a biased interleukin-2 (IL-2) fusion protein and a major histocompatibility complex (MHC) class II loaded with a myelin peptide. These tolerogenic MPs (Tol-MPs) were validated in vitro and then evaluated in a mouse model of MS, experimental autoimmune encephalomyelitis (EAE). Tol-MPs promoted sustained disease reversal in 100% of mice and full recovery in 38% of mice with symptomatic EAE. Tol-MPs are a promising platform for treatment of autoimmune diseases.

DAPTA, a C-C Chemokine Receptor 5 (CCR5), Leads to the Downregulation of Notch/NF-κB Signaling and Proinflammatory Mediators in CD40+ Cells in Experimental Autoimmune Encephalomyelitis Model in SJL/J Mice.

Multiple sclerosis (MS) is an autoimmune inflammatory disease of the central nervous system characterized by motor deficits, cognitive impairment, fatigue, pain, and sensory and visual dysfunction. CD40, highly expressed in B cells, plays a significant role in MS pathogenesis. The experimental autoimmune encephalomyelitis (EAE) mouse model of MS has been well established, as well as its relevance in MS patients. This study aimed to evaluate the therapeutic potential of DAPTA, a selective C-C chemokine receptor 5 (CCR5) antagonist in the murine model of MS, and to expand the knowledge of its mechanism of action. Following the induction of EAE, DAPTA was administrated (0.01 mg/kg, i.p.) daily from day 14 to day 42. We investigated the effects of DAPTA on NF-κB p65, IκBα, Notch-1, Notch-3, GM-CSF, MCP-1, iNOS, and TNF-α in CD40+ spleen B cells using flow cytometry. Furthermore, we also analyzed the effect of DAPTA on NF-κB p65, IκBα, Notch-1, Notch-3, GM-CSF, MCP-1, iNOS, and TNF-α mRNA expression levels using qRT-PCR in brain tissue. EAE mice treated with DAPTA showed substantial reductions in NF-κB p65, Notch-1, Notch-3, GM-CSF, MCP-1, iNOS, and TNF-α but an increase in the IκBα of CD40+ B lymphocytes. Moreover, EAE mice treated with DAPTA displayed decreased NF-κB p65, Notch-1, Notch-3, GM-CSF, MCP-1, iNOS, and TNF-α and but showed increased IκBα mRNA expression levels. This study showed that DAPTA has significant neuroprotective potential in EAE via the downregulation of inflammatory mediators and NF-κB/Notch signaling. Collectively, DAPTA might have potential therapeutic targets for use in MS treatment.

Imaging immunomodulatory treatment responses in a multiple sclerosis mouse model using hyperpolarized 13C metabolic MRI

BackgroundIn recent years, the ability of conventional magnetic resonance imaging (MRI), including T1 contrast-enhanced (CE) MRI, to monitor high-efficacy therapies and predict long-term disability in multiple sclerosis (MS) has been challenged. Therefore, non-invasive methods to improve MS lesions detection and monitor therapy response are needed.MethodsWe studied the combined cuprizone and experimental autoimmune encephalomyelitis (CPZ-EAE) mouse model of MS, which presents inflammatory-mediated demyelinated lesions in the central nervous system as commonly seen in MS patients. Using hyperpolarized 13C MR spectroscopy (MRS) metabolic imaging, we measured cerebral metabolic fluxes in control, CPZ-EAE and CPZ-EAE mice treated with two clinically-relevant therapies, namely fingolimod and dimethyl fumarate. We also acquired conventional T1 CE MRI to detect active lesions, and performed ex vivo measurements of enzyme activities and immunofluorescence analyses of brain tissue. Last, we evaluated associations between imaging and ex vivo parameters.ResultsWe show that hyperpolarized [1-13C]pyruvate conversion to lactate is increased in the brain of untreated CPZ-EAE mice when compared to the control, reflecting immune cell activation. We further demonstrate that this metabolic conversion is significantly decreased in response to the two treatments. This reduction can be explained by increased pyruvate dehydrogenase activity and a decrease in immune cells. Importantly, we show that hyperpolarized 13C MRS detects dimethyl fumarate therapy, whereas conventional T1 CE MRI cannot.ConclusionsIn conclusion, hyperpolarized MRS metabolic imaging of [1-13C]pyruvate detects immunological responses to disease-modifying therapies in MS. This technique is complementary to conventional MRI and provides unique information on neuroinflammation and its modulation.

GM-CSF Promotes the Survival of Peripheral-Derived Myeloid Cells in the Central Nervous System for Pain-Induced Relapse of Neuroinflammation.

We recently discovered a (to our knowledge) new neuroimmune interaction named the gateway reflex, in which the activation of specific neural circuits establishes immune cell gateways at specific vessel sites in organs, leading to the development of tissue-specific autoimmune diseases, including a multiple sclerosis (MS) mouse model, experimental autoimmune encephalomyelitis (EAE). We have reported that peripheral-derived myeloid cells, which are CD11b+MHC class II+ and accumulate in the fifth lumbar (L5) cord during the onset of a transfer model of EAE (tEAE), play a role in the pain-mediated relapse via the pain-gateway reflex. In this study, we investigated how these cells survive during the remission phase to cause the relapse. We show that peripheral-derived myeloid cells accumulated in the L5 cord after tEAE induction and survive more than other immune cells. These myeloid cells, which highly expressed GM-CSFRα with common β chain molecules, grew in number and expressed more Bcl-xL after GM-CSF treatment but decreased in number by blockade of the GM-CSF pathway, which suppressed pain-mediated relapse of neuroinflammation. Therefore, GM-CSF is a survival factor for these cells. Moreover, these cells were colocalized with blood endothelial cells (BECs) around the L5 cord, and BECs expressed a high level of GM-CSF. Thus, GM-CSF from BECs may have an important role in the pain-mediated tEAE relapse caused by peripheral-derived myeloid cells in the CNS. Finally, we found that blockade of the GM-CSF pathway after pain induction suppressed EAE development. Therefore, GM-CSF suppression is a possible therapeutic approach in inflammatory CNS diseases with relapse, such as MS.

Insights into the mechanism of oligodendrocyte protection and remyelination enhancement by the integrated stress response.

central nervous system (CNS) inflammation triggers activation of the integrated stress response (ISR). We previously reported that prolonging the ISR protects remyelinating oligodendrocytes and promotes remyelination in the presence of inflammation. However, the exact mechanisms through which this occurs remain unknown. Here, we investigated whether the ISR modulator Sephin1 in combination with the oligodendrocyte differentiation enhancing reagent bazedoxifene (BZA) is able to accelerate remyelination under inflammation, and the underlying mechanisms mediating this pathway. We find that the combined treatment of Sephin1 and BZA is sufficient to accelerate early-stage remyelination in mice with ectopic IFN-γ expression in the CNS. IFN-γ, which is a critical inflammatory cytokine in multiple sclerosis (MS), inhibits oligodendrocyte precursor cell (OPC) differentiation in culture and triggers a mild ISR. Mechanistically, we further show that BZA promotes OPC differentiation in the presence of IFN-γ, while Sephin1 enhances the IFN-γ-induced ISR by reducing protein synthesis and increasing RNA stress granule formation in differentiating oligodendrocytes. Finally, pharmacological suppression of the ISR blocks stress granule formation in vitro and partially lessens the beneficial effect of Sephin1 on disease progression in a mouse model of MS, experimental autoimmune encephalitis (EAE). Overall, our findings uncover distinct mechanisms of action of BZA and Sephin1 on oligodendrocyte lineage cells under inflammatory stress, suggesting that a combination therapy may effectively promote restoring neuronal function in MS patients.

Multiparametric magnetic resonance imagingfor detection of pathological changes in the central nervous system of a mouse model of multiple sclerosis in vivo.

Multiple sclerosis (MS) is an autoimmune disease involving demyelination and axonal damage in the central nervous system (CNS). In this study, we investigated pathological changes in the lumbar spinal cord of C57BL/6 mice induced with progressive experimental autoimmune encephalomyelitis (EAE) disease using 9.4-T magnetic resonance imaging (MRI). Multiparametric MRI measurements including MR spectroscopy, diffusion tensor imaging (DTI) and volumetric analyses were applied to detect metabolic changes in the CNS of EAE mice. Compared with healthy mice, EAE mice showed a significant reduction in N-acetyl aspartate and increases in choline, glycine, taurine and lactate. DTI revealed a significant reduction in fractional anisotropy and axial diffusivity and an increase in radial diffusivity in the lumbar spinal cord white matter (WM), while in the grey matter (GM), fractional anisotropy increased. High-resolution structural imaging also revealed lumbar spinal cord WM hypertrophy and GM atrophy. Importantly, these MRI changes were strongly correlated with EAE disease scoring and pathological changes in the lumbar (L2-L6), particularly WM demyelination lesions and aggregation of immune cells (microglia/macrophages and astrocytes) in this region. This study identified changes in MRI biomarker signatures that can be useful for evaluating the efficacy of novel drugs using EAE models in vivo.

The role of melatonin in potentiation the curative effect of Mesenchymal Stem cells in cuprizone mice Model of Multiple Sclerosis in subcortical white matter tissues.

The role of melatonin in potentiation the curative effect of Mesenchymal Stem cells in cuprizone mice Model of Multiple Sclerosis in subcortical white matter tissues.

Sequential treatment with a TNFR2 agonist and a TNFR1 antagonist improves outcomes in a humanized mouse model for MS

TNF signaling is an essential regulator of cellular homeostasis. Through its two receptors TNFR1 and TNFR2, soluble versus membrane-bound TNF enable cell death or survival in a variety of cell types. TNF-TNFRs signaling orchestrates important biological functions such as inflammation, neuronal activity as well as tissue de- and regeneration. TNF-TNFRs signaling is a therapeutic target for neurodegenerative diseases such as multiple sclerosis (MS) and Alzheimer’s disease (AD), but animal and clinical studies yielded conflicting findings. Here, we ask whether a sequential modulation of TNFR1 and TNFR2 signaling is beneficial in experimental autoimmune encephalomyelitis (EAE), an experimental mouse model that recapitulates inflammatory and demyelinating aspects of MS. To this end, human TNFR1 antagonist and TNFR2 agonist were administered peripherally at different stages of disease development in TNFR-humanized mice. We found that stimulating TNFR2 before onset of symptoms leads to improved response to anti-TNFR1 therapeutic treatment. This sequential treatment was more effective in decreasing paralysis symptoms and demyelination, when compared to single treatments. Interestingly, the frequency of the different immune cell subsets is unaffected by TNFR modulation. Nevertheless, treatment with only a TNFR1 antagonist increases T-cell infiltration in the central nervous system (CNS) and B-cell cuffing at the perivascular sites, whereas a TNFR2 agonist promotes Treg CNS accumulation. Our findings highlight the complicated nature of TNF signaling which requires a timely balance of selective activation and inhibition of TNFRs in order to exert therapeutic effects in the context of CNS autoimmunity.

MHV-68 induces central nervous system autoimmunity in an MBP-specific TCR transgenic mouse model of multiple sclerosis

Abstract Multiple Sclerosis (MS) is a demyelinating autoimmune disease of the central nervous system. Latent infection with Epstein-Barr virus (EBV) has been identified as a necessary yet insufficient factor in the development of the disease. Several groups have demonstrated that the murine EBV analogue, MHV-68, exacerbates disease severity in experimental autoimmune encephalomyelitis (EAE). However, the induction of EAE requires immunization and does not fully replicate the clinical features of MS. We sought to develop a virus-inducible model that accurately represents MS etiology and does not rely on classical EAE immunization. Using a transgenic mouse line with a myelin basic protein-specific T cell receptor, we found that MHV-68 induces demyelinating disease in 72% of infected mice. These mice exhibit clinical features such as optic neuritis, incontinence, and head tilt, which are commonly observed in MS patients but not in mice with EAE. This phenomenon was specific to MHV-68 and was not seen with other viral pathogens including PR8 influenza. Our work demonstrates that latent gammaherpesvirus infection can drive CNS autoimmunity in genetically predisposed mice without prior EAE induction, thus providing a more natural murine model of MS. National Institute of Health R01AI140741-04