Understanding pathogenesis and therapy of multiple sclerosis via animal models: 70 years of merits and culprits in experimental autoimmune encephalomyelitis research

MiR-146a promotes remyelination in a cuprizone model of demyelinating injury

The death of mature oligodendrocytes (OLs) which are the sole myelinating cells of the central nervous system (CNS), leads to demyelination and functional deficits. Currently, there is lack of effective remyelination therapies for patients with demyelinating diseases. MicroRNAs (miRNAs) mediate OL function. We hypothesized that miR-146a, by inactivating interleukin-1 receptor-associated kinase 1 (IRAK1), promotes differentiation of oligodendrocyte progenitor cells (OPCs) and thereby enhances remyelination. To test this hypothesis, a demyelination model induced by a cuprizone (CPZ) diet was employed, in which C57BL/6J mice were fed with a CPZ diet for 5weeks. After termination of CPZ diet, the mice were randomly treated with continuous infusion of miR-146a mimics or mimic controls into the corpus callosum for 7days. Compared to the mimic control, infusion of miR-146a mimics facilitated remyelination assessed by increased myelin basic proteins in the corpus callosum, which was associated with augmentation of newly generated mature OLs. Infusion of miR-146a mimics also substantially elevated miR-146a levels in the corpus callosum and fluorescently tagged miR-146a mimics were mainly detected in OPCs. Western blot and double immmunofluorescent staining analysis showed that the miR-146a treatment considerably reduced IRAK1 protein levels and the number of IRAK1-positive cells, respectively. Collectively, these data indicate that exogenous miR-146a enhances remyelination, possibly by promoting OPCs to differentiate into myelinated OLs via targeting IRAK1.

Oligodendroglial fibroblast growth factor receptor 1 gene targeting protects mice from experimental autoimmune encephalomyelitis through ERK/AKT phosphorylation

Fibroblast growth factors (FGFs) exert diverse biological effects by binding and activation of specific fibroblast growth factor receptors (FGFRs). FGFs and FGFRs have been implicated in demyelinating pathologies including multiple sclerosis. In vitro activation of the FGF2/FGFR1 pathway results in downregulation of myelin proteins. FGF1, 2 and 9 have been shown to be involved in the pathology of multiple sclerosis. Recent studies on the function of oligodendroglial FGFR1 in a model of toxic demyelination showed that deletion of FGFR1 led to increased remyelination and preservation of axonal density and an increased number of mature oligodendrocytes. In the present study the in vivo function of oligodendroglial FGFR1 was characterized using an oligodendrocyte-specific genetic approach in the most frequently used model of multiple sclerosis the MOG_35-55 -induced EAE. Oligodendroglial FGFR1 deficient mice (referred to as Fgfr1^ind-/- ) showed a significantly ameliorated disease course in MOG_35-55 -induced EAE. Less myelin and axonal loss, and reduced lymphocyte and macrophage/microglia infiltration were found in Fgfr1^ind-/- mice. The reduction in disease severity in Fgfr1^ind-/- mice was accompanied by ERK/AKT phosphorylation, and increased expression of BDNF and TrkB. Reduced proinflammatory cytokine and chemokine expression was seen in Fgfr1^ind-/- mice compared with control mice. Considering that FGFR inhibitors are used in cancer trials, the oligodendroglial FGFR1 pathway may provide a new target for therapy in multiple sclerosis.

Laquinimod enhances central nervous system barrier functions

Laquinimod is currently being tested as a therapeutic drug in multiple sclerosis. However, its exact mechanism of action is still under investigation. Tracking of fluorescently-tagged encephalitogenic T cells during experimental autoimmune encephalomyelitis (EAE), an animal model for multiple sclerosis, revealed that laquinimod significantly reduces the invasion of pathogenic effector T cells into the CNS tissue. T-cell activation, differentiation and amplification within secondary lymphoid organs after immunization with myelin antigen, their migratory capacity and re-activation within the nervous tissue were either only mildly affected or remained unchanged. Instead, laquinimod directly impacted the functionality of the CNS vasculature. The expression of tight junction proteins p120 and ZO-1 in human brain endothelial cells was up-regulated upon laquinimod treatment, resulting in a significant increase in the transendothelial electrical resistance of confluent monolayers of brain endothelial cells. Similarly, expression of the adhesion molecule activated leukocyte cell adhesion molecule (ALCAM) and inflammatory chemokines CCL2 and IP-10 was suppressed, leading to a significant reduction in the migration of memory T_H1 and T_H17 lymphocytes across the blood brain barrier (BBB). Our data indicate that laquinimod exerts its therapeutic effects by tightening the BBB and limiting parenchymal invasion of effector T cells, thereby reducing CNS damage.

Sigma-1 (σ1) Receptor in Memory and Neurodegenerative Diseases

The sigma-1 (σ1) receptor has been associated with regulation of intracellular Ca2+ homeostasis, several cellular signaling pathways, and inter-organelle communication, in part through its chaperone activity. In vivo, agonists of the σ1 receptor enhance brain plasticity, with particularly well-described impact on learning and memory. Under pathological conditions, σ1 receptor agonists can induce cytoprotective responses. These protective responses comprise various complementary pathways that appear to be differentially engaged according to pathological mechanism. Recent studies have highlighted the efficacy of drugs that act through the σ1 receptor to mitigate symptoms associated with neurodegenerative disorders with distinct mechanisms of pathogenesis. Here, we will review genetic and pharmacological evidence of σ1 receptor engagement in learning and memory disorders, cognitive impairment, and neurodegenerative diseases, including Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis, multiple sclerosis, and Huntington's disease.

Targeted delivery of glucocorticoids to macrophages in a mouse model of multiple sclerosis using inorganic-organic hybrid nanoparticles

Glucocorticoids (GC) are widely used to treat acute relapses in multiple sclerosis (MS) patients, but their application is accompanied by side effects due to their broad spectrum of action. Here, we report on the therapeutic option to apply GC via inorganic-organic hybrid nanoparticles (IOH-NP) with the composition [ZrO]²⁺[(BMP)_0.9(FMN)_0.1]^2- (designated BMP-NP with BMP: betamethasone phosphate; FMN: flavinmononucleotide). We found that these BMP-NP have an increased cell type-specificity compared to free GC while retaining full therapeutic efficacy in a mouse model of MS. BMP-NP were preferentially taken up by phagocytic cells and modulated macrophages in vivo more efficiently than T cells. When GC were applied in the form of BMP-NP, treatment of neuroinflammatory disease in mice exclusively depended on the control of macrophage function whereas effects on T cells and brain endothelial cells were dispensable for therapeutic efficacy. Importantly, BMP-NP were not only active in mice but also showed strong activity towards monocytes isolated from healthy human volunteers. We conclude that application of GC via IOH-NP has the potential to improve MS therapy in the future.

Heterogeneity in oligodendroglia: Is it relevant to mouse models and human disease?

There are many lines of evidence indicating that oligodendrocyte progenitor cells and oligodendrocyte populations in the central nervous system (CNS) are heterogeneous based on their developmental origins as well as from morphological and molecular criteria. Whether these distinctions reflect functional heterogeneity is less clear and has been the subject of considerable debate. Recent findings, particularly from knockout mouse models, have provided new evidence for regional variations in myelination phenotypes, particularly between brain and spinal cord. These data raise the possibility that oligodendrocytes in these regions have different functional capacities and/or ability to compensate for loss of a specific gene. The goal of this review is to briefly revisit the evidence for oligodendrocyte heterogeneity and then to present data from transgenic and demyelinating mouse models suggesting functional heterogeneity in myelination, demyelination, and remyelination in the CNS and, finally, to discuss the implications of these findings for human diseases. © 2016 Wiley Periodicals, Inc.

Environmental factors in autoimmune diseases and their role in multiple sclerosis

An increase in autoimmune diseases poses a socioeconomic challenge worldwide. Predisposing genetic risk has been identified, yet environmental factors make up a significant part of the risk in disease initiation and propagation. Next to improved hygiene and a gross reduction of infections, changes in dietary habits are one of the most evident Western lifestyle factors potentially associated with the increase in autoimmune diseases. Growing evidence suggests that particularly a typical 'Western diet', rich in saturated fat and salt and related pathologies can have a profound impact on local and systemic immune responses under physiologic and autoimmune conditions such as in multiple sclerosis (MS). In this review, we discuss recent findings on environmental factors influencing autoimmunity with an emphasis on the impact of 'Western diet' on immune homeostasis and gut microbiota in MS.

CatWalk gait analysis in a rat model of multiple sclerosis

Background

Myelin oligodendrocyte glycoprotein (MOG)-induced experimental autoimmune encephalomyelitis (EAE) is a widely used animal model for multiple sclerosis. The characteristic feature of the MOG-EAE model in Brown Norway rats is consistent involvement of the spinal cord resulting in limb paresis. The aim of the study was to investigate whether early subclinical gait abnormalities are present in this animal model and can be detected by CatWalk XT, a fully automated gait analysis system. Furthermore, we investigated the usability of CatWalk system for treatment studies.

Results

Our gait analysis showed no preclinical abnormalities in MOG-EAE animals. Nevertheless, we characterized a combination of gait parameters that display a high predictive capacity in regard to disease onset. Our detailed histopathological analysis of the spinal cord revealed that lesion formation starts in the lumbar region and propagates toward the cervical part of the spinal cord during the disease course. In the treatment study, the stabilization of gait parameters under the treatment with methylprednisolone was detected in CatWalk as well as in traditional EAE-scoring system.

Conclusions

The results from CatWalk test indicate no benefit of lab-intensive automated gait system in EAE-model with chronic-progressive disease course as well as in therapeutic studies with pronounced effect on the severity of clinical symptoms. However, due to its quantitative and objective nature this system may display a refined test to detect small but functional relevant changes in regeneration-orientated studies.

Amelioration of Experimental Autoimmune Encephalomyelitis by Isogarcinol Extracted from Garcinia mangostana L. Mangosteen

Isogarcinol is a new natural immunosuppressant that was extracted from Garcinia mangostana L. in our laboratory. Knowledge of its effects on treatable diseases and its mechanism of action is still very limited. In this study, we explored the therapeutic effect of isogarcinol in experimental autoimmune encephalomyelitis (EAE), a murine model of multiple sclerosis (MS). Treatment with oral 100 mg/kg isogarcinol markedly ameliorated clinical scores, alleviated inflammation and demyelination of the spinal cord, and reduced intracranial lesions in EAE mice. The percentages of Th cells and macrophages were also strongly reduced. Isogarcinol appeared to act by inhibiting T helper (Th) 1 and Th17 cell differentiation via the janus kinase/signal transducers and activators of transcription pathway and by impairing macrophage function. Our data suggest that isogarcinol has the potential to be an effective therapeutic agent of low toxicity for treating MS and other autoimmune diseases.

Live Imaging of Immune Responses in Experimental Models of Multiple Sclerosis

Experimental autoimmune encephalomyelitis (EAE) is the most common animal model of multiple sclerosis (MS), a chronic inflammatory autoimmune disease of the central nervous system (CNS) characterized by multifocal perivascular infiltrates that predominantly comprise lymphocytes and macrophages. During EAE, autoreactive T cells first become active in the secondary lymphoid organs upon contact with antigen-presenting cells (APCs), and then gain access to CNS parenchyma, through a compromised blood–brain barrier, subsequently inducing inflammation and demyelination. Two-photon laser scanning microscopy (TPLSM) is an ideal tool for intravital imaging because of its low phototoxicity, deep tissue penetration, and high resolution. In the last decade, TPLSM has been used to visualize the behavior of T cells and their contact with APCs in the lymph nodes (LNs) and target tissues in several models of autoimmune diseases. The leptomeninges and cerebrospinal fluid represent particularly important points for T cell entry into the CNS and reactivation following contact with local APCs during the preclinical phase of EAE. In this review, we highlight recent findings concerning the pathogenesis of EAE and MS, emphasizing the use of TPLSM to characterize T cell activation in the LNs and CNS, as well as the mechanisms of tolerance induction. Furthermore, we discuss how advanced imaging unveils disease mechanisms and helps to identify novel therapeutic strategies to treat CNS autoimmunity and inflammation.

Adipose Stromal Vascular Fraction-Mediated Improvements at Late-Stage Disease in a Murine Model of Multiple Sclerosis

Multiple sclerosis (MS) is a common neurodegenerative disease and remains an unmet clinical challenge. In MS, an autoimmune response leads to immune cell infiltration, inflammation, demyelination, and lesions in central nervous system (CNS) tissues resulting in tremors, fatigue, and progressive loss of motor function. These pathologic hallmarks are effectively reproduced in the murine experimental autoimmune encephalomyelitis (EAE) model. The stromal vascular fraction (SVF) of adipose tissue is composed of adipose-derived stromal/stem cells (ASC), adipocytes, and various leukocytes. The SVF can be culture expanded to generate ASC lines. Clinical trials continue to demonstrate the safety and efficacy of ASC therapies for treating several diseases. However, little is known about the effectiveness of the SVF for neurodegenerative diseases, such as MS. At late-stage disease, EAE mice show severe motor impairment. The goal for these studies was to test the effectiveness of SVF cells and ASC in EAE mice after the onset of neuropathology. The clinical scoring, behavior, motor function, and histopathologic analyses revealed significant improvements in EAE mice treated with the SVF or ASC. Moreover, SVF treatment mediated more robust improvements to CNS pathology than ASC treatment based on significant modulations of inflammatory factors. The most pronounced changes following SVF treatment were the high levels of interleukin-10 in the peripheral blood, lymphoid and CNS tissues along with the induction of regulatory T cells in the lymph nodes which indicate potent immunomodulatory effects. The data indicate SVF cells effectively ameliorated the EAE immunopathogenesis and supports the potential use of SVF for treating MS. Stem Cells 2017;35:532-544.

Liposomal nano-drugs based on amphipathic weak acid steroid prodrugs for treatment of inflammatory diseases

BACKGROUND

Steroids are the most efficacious anti-inflammatory agents. However, their toxicities and side-effects compromise their clinical application. Various strategies and major efforts were dedicated for formulating viable liposomal glucocorticosteroids (GCs), so far none of these were approved.

OBJECTIVES

To evaluate these approaches for formulating GC-delivery systems, especially liposomes, and with focus on the Barenholz Lab experience.

METHODS

We developed PEGylated nano-liposomes (NSSL) remotely loaded with water-soluble amphipathic weak acid GC-prodrugs. Their remote loading results in high, efficient and stable loading to the level that enables human clinical use. We characterized them for their physical chemistry and stability. We demonstrated their therapeutic efficacy in relevant animal models and studied their pharmacokinetics (PK), biodistribution (BD) and pharmacodynamics advantages over the free pro-drugs.

RESULTS

Our steroidal nano-drugs demonstrate much superior PK, BD, tolerability and therapeutic efficacies compared to the free pro-drugs and to most drugs currently used to treat these diseases. These nano-drugs act as robust immune-suppressors, affecting cytokines secretion and diminishing hemorrhage and edema.

CONCLUSIONS

The combination of improved physical-chemistry, PK, BD, tolerability and therapeutic efficacy of these steroidal nano-drugs over the pro-drugs "as-is" support their further clinical development as potential therapeutic agents for treating inflammatory diseases.

New Insights into the Role of Oxidative Stress Mechanisms in the Pathophysiology and Treatment of Multiple Sclerosis

Multiple sclerosis (MS) is a multifactorial disease of the central nervous system (CNS) characterized by an inflammatory process and demyelination. The etiology of the disease is still not fully understood. Therefore, finding new etiological factors is of such crucial importance. It is suspected that the development of MS may be affected by oxidative stress (OS). In the acute phase OS initiates inflammatory processes and in the chronic phase it sustains neurodegeneration. Redox processes in MS are associated with mitochondrial dysfunction, dysregulation of axonal bioenergetics, iron accumulation in the brain, impaired oxidant/antioxidant balance, and OS memory. The present paper is a review of the current literature about the role of OS in MS and it focuses on all major aspects. The article explains the mechanisms of OS, reports unique biomarkers with regard to their clinical significance, and presents a poorly understood relationship between OS and neurodegeneration. It also provides novel methods of treatment, including the use of antioxidants and the role of antioxidants in neuroprotection. Furthermore, adding new drugs in the treatment of relapse may be useful. The article considers the significance of OS in the current treatment of MS patients.

Interferon Gamma: Influence on Neural Stem Cell Function in Neurodegenerative and Neuroinflammatory Disease

Interferon-gamma (IFNγ), a pleiotropic cytokine, is expressed in diverse neurodegenerative and neuroinflammatory conditions. Its protective mechanisms are well documented during viral infections in the brain, where IFNγ mediates non-cytolytic viral control in infected neurons. However, IFNγ also plays both protective and pathological roles in other central nervous system (CNS) diseases. Of the many neural cells that respond to IFNγ, neural stem/progenitor cells (NSPCs), the only pluripotent cells in the developing and adult brain, are often altered during CNS insults. Recent studies highlight the complex effects of IFNγ on NSPC activity in neurodegenerative diseases. However, the mechanisms that mediate these effects, and the eventual outcomes for the host, are still being explored. Here, we review the effects of IFNγ on NSPC activity during different pathological insults. An improved understanding of the role of IFNγ would provide insight into the impact of immune responses on the progression and resolution of neurodegenerative diseases.

Enterococcus faecium strain L-3 and glatiramer acetate ameliorate experimental allergic encephalomyelitis in rats by affecting different populations of immune cells

The effect of probiotic Enterococcus faecium strain L-3 was studied in rats with experimental allergic encephalomyelitis (EAE). Glatiramer acetate (GA) was used as control drug. E. faecium strain L-3 and GA both were able to reduce the severity of EAE in a similar fashion. Both approaches increased the proportion of EAE resistant rats and rats with mild disease, prolonged the inductive phase of EAE and reduced the disease duration. Study of the phenotypes of immune cells in blood revealed the differences in immunoregulatory pathways that mediate the protective action of probiotic or GA treatment of EAE. The presence of pronounced protective and immunomodulating effects of the probiotic E. faecium strain L-3 opens an opportunity of its application for the treatment of multiple sclerosis.

Chronic iron overload induces gender-dependent changes in iron homeostasis, lipid peroxidation and clinical course of experimental autoimmune encephalomyelitis

To analyze iron- and gender-dependent mechanisms possibly involved in pathogenesis of multiple sclerosis (MS) in this study we evaluated the effects of iron overload (IO) on iron status and lipid peroxidation processes (LPO) in tissues of female and male DA rats during chronic relapsing experimental autoimmune encephalomyelitis, a well-established MS animal model. Rats were treated by iron sucrose (75mg/kg bw/day) or with saline solution during two weeks before the sensitization with bovine brain homogenate in complete Freund's adjuvant. Clinical signs of EAE were monitored during 29 days. Serum and tissues of CNS and liver were sampled before immunization and at day 13th post immunization (during acute phase of EAE). The determination of ferritin, iron, malondialdehyde (MDA) and 4-hydroxynonenal (4-HNE) and evaluation of histopathology were performed by ELISA, ICP spectrometry and immunohistochemistry. Results showed that IO in female EAE rats accelerated the onset of disease. In contrast, in male rats it accelerated the progression of disease and increased the mortality rate. During acute phase of EAE female IO rats sequestered more Fe in the liver, spinal cord and in the brain and produced more ferritin than male EAE rats. Male rats, however, reacted on IO by higher production of MDA or 4-HNE in the neural tissues and showed greater signs of plaque formation and gliosis in spinal cord. The data point to sexual dimorphism in mechanisms that regulate peripheral and brain iron homeostasis and imply that men and women during MS might be differentially vulnerable to exogenous iron overload.

ERβ-Dependent Direct Suppression of Human and Murine Th17 Cells and Treatment of Established Central Nervous System Autoimmunity by a Neurosteroid

Multiple sclerosis (MS), an autoimmune disease of the CNS, is mediated by autoreactive Th cells. A previous study showed that the neurosteroid dehydroepiandrosterone (DHEA), when administered preclinically, could suppress progression of relapsing-remitting experimental autoimmune encephalomyelitis (EAE). However, the effects of DHEA on human or murine pathogenic immune cells, such as Th17, were unknown. In addition, effects of this neurosteroid on symptomatic disease, as well as the receptors involved, had not been investigated. In this study, we show that DHEA suppressed peripheral responses from patients with MS and reversed established paralysis and CNS inflammation in four different EAE models, including the 2D2 TCR-transgenic mouse model. DHEA directly inhibited human and murine Th17 cells, inducing IL-10-producing regulatory T cells. Administration of DHEA in symptomatic mice induced regulatory CD4(+) T cells that were suppressive in an IL-10-dependent manner. Expression of the estrogen receptor β by CD4(+) T cells was necessary for DHEA-mediated EAE amelioration, as well as for direct downregulation of Th17 responses. TGF-β1 as well as aryl hydrocarbon receptor activation was necessary for the expansion of IL-10-producing T cells by DHEA. Thus, our studies demonstrate that compounds that inhibit pathogenic Th17 responses and expand functional regulatory cells could serve as therapeutic agents for autoimmune diseases, such as MS.

High-dose erythropoietin in patients with progressive multiple sclerosis: A randomized, placebo-controlled, phase 2 trial

Background:

Erythropoietin (EPO) is a part of an endogenous neuroprotective system in the brain and may address pathophysiological mechanisms in progressive multiple sclerosis (MS).

Objective:

To evaluate a treatment effect of EPO on progressive MS.

Methods:

This was a single-center, randomized, double-blind, placebo-controlled phase 2 trial, in which 52 patients with secondary or primary progressive MS were allocated to treatment with recombinant EPO (48,000 IU) or placebo, administered intravenously 17 times during 24 weeks. Patients had an Expanded Disability Status Score (EDSS) from 4 to 6.5 and clinical progression without relapses in the 2 preceding years. The primary outcome was the change in a composite measure of maximum gait distance, hand dexterity, and cognition from baseline to 24 weeks.

Results:

A total of 50 patients completed the study. Venesection was performed often but no thromboembolic events occurred. We found no difference in the primary outcome between the EPO and the placebo group using the intention-to-treat principle ( p = 0.22). None of the secondary outcomes, neither clinical nor magnetic resonance imaging (MRI) measures showed any significant differences.

Conclusion:

This study provides class II evidence that treatment with high-dose EPO is not an effective treatment in patients with moderately advanced progressive MS.

CD20 therapies in multiple sclerosis and experimental autoimmune encephalomyelitis - Targeting T or B cells?

MS is widely considered to be a T cell-mediated disease although T cell immunotherapy has consistently failed, demonstrating distinct differences with experimental autoimmune encephalomyelitis (EAE), an animal model of MS in which T cell therapies are effective. Accumulating evidence has highlighted that B cells also play key role in MS pathogenesis. The high frequency of oligoclonal antibodies in the CSF, the localization of immunoglobulin in brain lesions and pathogenicity of antibodies originally pointed to the pathogenic role of B cells as autoantibody producing plasma cells. However, emerging evidence reveal that B cells also act as antigen presenting cells, T cell activators and cytokine producers suggesting that the strong efficacy of anti-CD20 antibody therapy observed in people with MS may reduce disease progression by several different mechanisms. Here we review the evidence and mechanisms by which B cells contribute to disease in MS compared to findings in the EAE model.

Autoantibodies to heterogeneous nuclear ribonuclear protein A1 (hnRNPA1) cause altered 'ribostasis' and neurodegeneration; the legacy of HAM/TSP as a model of progressive multiple sclerosis

Several years following its discovery in 1980, infection with human T-lymphotropic virus type 1 (HTLV-1) was shown to cause HTLV-1 associated myelopathy/tropical spastic paraparesis (HAM/TSP), a disease biologically similar to progressive forms of multiple sclerosis (MS). In this manuscript, we review some of the clinical, pathological, and immunological similarities between HAM/TSP and MS with an emphasis on how autoantibodies to an RNA binding protein, heterogeneous nuclear ribonuclear protein A1 (hnRNP A1), might contribute to neurodegeneration in immune mediated diseases of the central nervous system.

Lymphocryptovirus Infection of Nonhuman Primate B Cells Converts Destructive into Productive Processing of the Pathogenic CD8 T Cell Epitope in Myelin Oligodendrocyte Glycoprotein

EBV is the major infectious environmental risk factor for multiple sclerosis (MS), but the underlying mechanisms remain obscure. Patient studies do not allow manipulation in vivo. We used the experimental autoimmune encephalomyelitis (EAE) models in the common marmoset and rhesus monkey to model the association of EBV and MS. We report that B cells infected with EBV-related lymphocryptovirus (LCV) are requisite APCs for MHC-E-restricted autoaggressive effector memory CTLs specific for the immunodominant epitope 40-48 of myelin oligodendrocyte glycoprotein (MOG). These T cells drive the EAE pathogenesis to irreversible neurologic deficit. The aim of this study was to determine why LCV infection is important for this pathogenic role of B cells. Transcriptome comparison of LCV-infected B cells and CD20(+) spleen cells from rhesus monkeys shows increased expression of genes encoding elements of the Ag cross-presentation machinery (i.e., of proteasome maturation protein and immunoproteasome subunits) and enhanced expression of MHC-E and of costimulatory molecules (CD70 and CD80, but not CD86). It was also shown that altered expression of endolysosomal proteases (cathepsins) mitigates the fast endolysosomal degradation of the MOG40-48 core epitope. Finally, LCV infection also induced expression of LC3-II(+) cytosolic structures resembling autophagosomes, which seem to form an intracellular compartment where the MOG40-48 epitope is protected against proteolytic degradation by the endolysosomal serine protease cathepsin G. In conclusion, LCV infection induces a variety of changes in B cells that underlies the conversion of destructive processing of the immunodominant MOG40-48 epitope into productive processing and cross-presentation to strongly autoaggressive CTLs.

Effects of Neuroinflammation on Neural Stem Cells

Neural stem/progenitor cells (NSCs/NPCs) are present in different locations in the central nervous system. In the subgranular zone (SGZ) there is a constant generation of new neurons under normal conditions. New neurons are also formed from the subventricular zone (SVZ) NSCs, and they migrate anteriorly as neuroblast to the olfactory bulb in rodents, whereas in humans migration is directed toward striatum. Most CNS injuries elicit proliferation and migration of the NSCs toward the injury site, indicating the activation of a regenerative response. However, regeneration from NSC is incomplete, and this could be due to detrimental cues encountered during inflammation. Different CNS diseases and trauma cause activation of the innate and adaptive immune responses that influence the NSCs. Furthermore, NSCs in the brain react differently to inflammatory cues than their counterparts in the spinal cord. In this review, we have summarized the effects of inflammation on NSCs in relation to their origin and briefly described the NSC activity during different neurological diseases or experimental models.

In vivo imaging in autoimmune diseases in the central nervous system

Intravital imaging is becoming more popular and is being used to visualize cellular motility and functions. In contrast to in vitro analysis, which resembles in vivo analysis, intravital imaging can be used to observe and analyze cells directly in vivo. In this review, I will summarize recent imaging studies of autoreactive T cell infiltration into the central nervous system (CNS) and provide technical background. During their in vivo journey, autoreactive T cells interact with many different cells. At first, autoreactive T cells interact with endothelial cells in the airways of the lung or with splenocytes, where they acquire a migratory phenotype to infiltrate into the CNS. After arriving at the CNS, they interact with endothelial cells of the leptomeningeal vessels or the choroid plexus before passing through the blood-brain barrier. CNS-infiltrating T cells become activated by recognizing endogenous autoantigens presented by local antigen-presenting cells (APCs). This activation was visualized in vivo by using protein-based sensors. One such sensor detects changes in intracellular calcium concentration as an early marker of T cell activation. Another sensor detects translocation of Nuclear factor of activated T-cells (NFAT) from cytosol to nucleus as a definitive sign of T cell activation. Importantly, intravital imaging is not just used to visualize cellular behavior. Together with precise analysis, intravital imaging deepens our knowledge of cellular functions in living organs and also provides a platform for developing therapeutic treatments.

MicroRNA223 promotes pathogenic T-cell development and autoimmune inflammation in central nervous system in mice

Multiple sclerosis (MS) is an incurable central nervous system autoimmune disease. Understanding MS pathogenesis is essential for the development of new MS therapies. In the present study, we identified a novel microRNA (miR) that regulates experimental autoimmune encephalomyelitis (EAE), an animal model of MS. Expression of miR223 was up-regulated specifically in spinal cords and lymphoid organs but not in other examined tissues. A global miR223 knockout (miR223(-/-) ) in mice led to a significant delay in EAE onset, reduction in spinal cord lesion, and lessening of neurological symptoms. These protective effects could be reproduced in bone marrow chimeras reconstituted with miR223(-/-) haematopoietic stem cells. We also found that miR223 deficiency reduced T helper type 1 (Th1) and Th17 infiltration into spinal cords. To address underlying mechanisms, we investigated the role of miR223 in regulating the function, development and interaction of the major immune cells. Expression of the genes associated with dendritic cell (DC) activation (CD86 and MHC II) and Th1 and Th17 differentiation [interleukin-12 (IL-12) and IL-23, respectively] was significantly decreased in the spleens of miR223(-/-) mice bearing EAE. The miR223(-/-) DCs expressed significantly lower levels of basal and lipopolysaccharide-induced IL-12 and IL-23 compared with the wild-type DCs. These data are consistent with the observed lower efficiency of miR223(-/-) DCs to support Th1 and Th17 differentiation from naive T cells over-expressing an EAE antigen-specific T-cell receptor. Our data suggest that miR223 promotes EAE, probably through enhancing DC activation and subsequently the differentiation of naive T cells toward Th1 and Th17 effector cells.

2'-5' oligoadenylate synthetase-like 1 (OASL1) deficiency suppresses central nervous system damage in a murine MOG-induced multiple sclerosis model

Type I Interferon (IFN-I) is critical for antiviral and antitumor defense. Additionally, IFN-I has been used for treating multiple sclerosis (MS), a chronic autoimmune disease of the central nervous system (CNS). Recently, we reported that 2'-5' oligoadenylate synthetase-like 1 (OASL1) negatively regulates IFN-I production upon viral infection and tumor challenge. Therefore, OASL1 deficient (Oasl1(-)(/)(-)) mice are resistant to viral infections and tumor challenge. In this study, we examined whether OASL1 plays a negative role in the development of autoimmune MS by using Oasl1(-)(/)(-) mice and a murine MS model, myelin oligodendrocyte glycoprotein (MOG)-induced experimental autoimmune encephalomyelitis (EAE). Oasl1(-)(/)(-) mice showed enhanced resistance to EAE development compared to wild-type (WT) mice. Additionally, EAE-induced Oasl1(-)(/)(-) mice showed fewer infiltrated immune cells such as T cells and macrophages in the CNS and less CNS inflammation, compared to WT mice. Collectively, these results indicate that OASL1 deficiency suppresses the development of MS-like autoimmunity and suggest that negative regulators of IFN-I could be good therapeutic targets for treating MS in humans.

ERβ in CD4+ T Cells Is Crucial for Ligand-Mediated Suppression of Central Nervous System Autoimmunity

The development of therapies for multiple sclerosis targeting pathogenic T cell responses remains imperative. Previous studies have shown that estrogen receptor (ER) β ligands could inhibit experimental autoimmune encephalomyelitis. However, the effects of ERβ-specific ligands on human or murine pathogenic immune cells, such as Th17, were not investigated. In this article, we show that the synthetic ERβ-specific ligand 4-(2-phenyl-5,7-bis[trifluoromethyl]pyrazolo[1,5-a]pyrimidin-3-yl)phenol (PHTPP) reversed established paralysis and CNS inflammation, characterized by a dramatic suppression of pathogenic Th responses as well as induction of IL-10-producing regulatory CD4(+) T cell subsets in vivo. Moreover, administration of PHTPP in symptomatic mice induced regulatory CD4(+) T cells that were suppressive in vivo. PHTPP-mediated experimental autoimmune encephalomyelitis amelioration was canceled in mice with ERβ-deficient CD4(+) T cells only, indicating that expression of ERβ by these cells is crucial for the observed therapeutic effect. Importantly, synthetic ERβ-specific ligands acting directly on CD4(+) T cells suppressed human and mouse Th17 cells, downregulating Th17 cell signature gene expression and expanding IL-10-producing T cells among them. TGF-β1 and aryl hydrocarbon receptor activation enhanced the ERβ ligand-mediated expansion of IL-10-producing T cells among Th17 cells. In addition, these ERβ-specific ligands promoted the induction and maintenance of Foxp3(+) T regulatory cells, as well as their in vitro suppressive function. Thus, ERβ-specific ligands targeting pathogenic Th17 cells and inducing functional regulatory cells represent a promising subset of therapeutic agents for multiple sclerosis.

Oral Tolerance Induction in Experimental Autoimmune Encephalomyelitis with Candida utilis Expressing the Immunogenic MOG35-55 Peptide

Multiple sclerosis (MS) is an autoimmune disease that attacks myelinated axons in the central nervous system. Induction of oral tolerance is a potent mechanism to prevent autoimmunity. The food yeast Candida utilis was used to test the therapeutic potential of oral tolerance induction in an animal model of human multiple sclerosis (MS). We constructed a C. utilis strain, which displays a fusion peptide composed of the encephalitogenic MOG35-55 peptide and the C. utilis Gas1 cell wall protein on its surface.By immunizing mice with MOG35-55 peptide experimental autoimmune encephalomyelitis (EAE) was induced in a mouse model. Feeding of mice with C. utilis that expresses MOG35-55 peptide on its surface was started seven days prior to immunization and was continued for ten days. Control animals were treated with wild-type fungus or left untreated. Untreated mice developed first clinical symptoms ten days post immunization (p. i.) with an ascending paralysis reaching maximal clinical disability at day 18 to 20 p. i.. Treatment with the wild-type strain demonstrated comparable clinical symptoms. In contrast, oral gavage of MOG35-55-presenting fungus ameliorated the development of EAE. In addition, incidence as well as maximal clinical disease severity were significantly reduced. Interestingly, reduction of disease severity also occurred in animals treated with heat-inactivated C. utilis cells indicating that tolerance induction was independent of fungal viability. Better disease outcome correlated with reduced demyelination and cellular inflammation in the spinal cord, lower T cell proliferation against rechallenge with MOG35-55 and more regulatory T cells in the lymph nodes. Our data demonstrate successful that using the food approved fungus C. utilis presenting the immunogenic MOG35-55 peptide on its surface induced an oral tolerance against this epitope in EAE. Further studies will reveal the nature and extent of an anti-inflammatory environment established by the treatment that prevents the development of an autoimmune disorder affecting the CNS.

DNA Vaccination Techniques

Multiple sclerosis (MS) is the most common inflammatory, demyelinating, and neurodegenerative disorder of the central nervous system (CNS) in humans. Although the etiology of MS remains unknown, several lines of evidence support the notion that autoimmunity against components of the myelin sheath plays a major role in susceptibility to and development of the disease. At present, there are no approved MS therapies aimed specifically toward downregulating antigen-specific autoreactive immune cells. One antigen-specific approach that appears promising for the treatment of MS is DNA vaccination. This technique has demonstrated efficacy in clinical trials while maintaining safety.Here, we describe the generation of DNA vaccines containing immunologically relevant antigens of MS. Moreover, we present a detailed protocol for the prophylactic and therapeutic administration of DNA vaccines via intramuscular injection targeting on the development of experimental autoimmune encephalomyelitis (EAE), an animal model resembling MS.

Neuroinflammation: the devil is in the details

There is significant interest in understanding inflammatory responses within the brain and spinal cord. Inflammatory responses that are centralized within the brain and spinal cord are generally referred to as 'neuroinflammatory'. Aspects of neuroinflammation vary within the context of disease, injury, infection, or stress. The context, course, and duration of these inflammatory responses are all critical aspects in the understanding of these processes and their corresponding physiological, biochemical, and behavioral consequences. Microglia, innate immune cells of the CNS, play key roles in mediating these neuroinflammatory responses. Because the connotation of neuroinflammation is inherently negative and maladaptive, the majority of research focus is on the pathological aspects of neuroinflammation. There are, however, several degrees of neuroinflammatory responses, some of which are positive. In many circumstances including CNS injury, there is a balance of inflammatory and intrinsic repair processes that influences functional recovery. In addition, there are several other examples where communication between the brain and immune system involves neuroinflammatory processes that are beneficial and adaptive. The purpose of this review is to distinguish different variations of neuroinflammation in a context-specific manner and detail both positive and negative aspects of neuroinflammatory processes. In this review, we will use brain and spinal cord injury, stress, aging, and other inflammatory events to illustrate the potential harm and benefits inherent to neuroinflammation. Context, course, and duration of the inflammation are highly important to the interpretation of these events, and we aim to provide insight into this by detailing several commonly studied insults. This article is part of the 60th anniversary supplemental issue.

Safety assessment of adjuvanted vaccines: Methodological considerations

Adjuvants mainly interact with the innate immune response and are used to enhance the quantity and quality of the downstream adaptive immune response to vaccine antigens. Establishing the safety of a new adjuvant-antigen combination is achieved through rigorous evaluation that begins in the laboratory, and that continues throughout the vaccine life-cycle. The strategy for the evaluation of safety pre-licensure is guided by the disease profile, vaccine indication, and target population, and it is also influenced by available regulatory guidelines. In order to allow meaningful interpretation of clinical data, clinical program methodology should be optimized and standardized, making best use of all available data sources. Post-licensure safety activities are directed by field experience accumulated pre- and post-licensure clinical trial data and spontaneous adverse event reports. Continued evolution of safety evaluation processes that keep pace with advances in vaccine technology and updated communication of the benefit-risk profile is necessary to maintain public confidence in vaccines.

CXCR3 signaling in glial cells ameliorates experimental autoimmune encephalomyelitis by restraining the generation of a pro-Th17 cytokine milieu and reducing CNS-infiltrating Th17 cells

BACKGROUND

Experimental autoimmune encephalomyelitis (EAE) is a mouse model of multiple sclerosis (MS). It has been shown that Th17 cells are critical for EAE pathogenesis. Mice lacking CXCR3 develop aggravated EAE compared with wild-type (WT) mice. This study investigated the effect of CXCR3 on Th17 expansion during EAE and further addressed the underlying mechanism.

METHODS

Both active EAE and adoptive-transfer EAE experiments were employed for studying EAE pathogenesis in WT and CXCR3(-/-) mice. Demyelination and leukocyte infiltration in the spinal cord of mice were analyzed by luxol fast blue staining and flow cytometry analysis, respectively. Glial cells expressing CXCR3 in the spinal cord were analyzed by immunofluorescence staining. Cytokine and chemokine levels in the spinal cord were analyzed using quantitative real-time PCR and enzyme-linked immunosorbent assay (ELISA). The glial cell line U87MG was employed for studying the CXCR3 signaling-mediated mechanism regulating Th17 expansion.

RESULTS

CXCR3(-/-) mice exhibited more severe EAE and had significantly increased central nervous system (CNS)-infiltrating Th17 cells compared with WT mice. Adoptive-transfer experiments showed that CXCR3(-/-) recipient mice that received Th17 cells polarized from splenocytes of myelin oligodendrocyte glycoprotein (MOG)-immunized CXCR3(-/-) mice or MOG-immunized WT mice always developed more severe EAE and had significantly increased CNS-infiltrating Th17 cells compared with WT recipient mice that received Th17 cells from the same origin. Furthermore, during EAE, the number of activated glial cells was increased in the CNS of MOG-immunized CXCR3(-/-) mice, and CXCR3-deficient glial cells expressed increased levels of cytokine genes required for Th17 expansion and recruitment. Finally, we found that extracellular signal-regulated kinase (ERK) activation elicited by CXCR3 signaling in U87MG cells attenuated the activation of NF-κB, a key transcription factor critical for the induction of IL-23 and CCL20, which are required for Th17 cell expansion and recruitment, respectively.

CONCLUSIONS

This study demonstrates a previously unrecognized role of CXCR3 signaling in glial cells in negatively regulating Th17 cell expansion during EAE. Our results demonstrate that, in addition to its well-known role in the recruitment of immune cells, CXCR3 in CNS glial cells plays a critical role in restraining the pro-Th17 cytokine/chemokine milieu during EAE, thereby diminishing Th17 cell expansion in the CNS and suppressing disease development.

Inherited and acquired disorders of myelin: The underlying myelin pathology

Remyelination is a major therapeutic goal in human myelin disorders, serving to restore function to demyelinated axons and providing neuroprotection. The target disorders that might be amenable to the promotion of this repair process are diverse and increasing in number. They range primarily from those of genetic, inflammatory to toxic origin. In order to apply remyelinating strategies to these disorders, it is essential to know whether the myelin damage results from a primary attack on myelin or the oligodendrocyte or both, and whether indeed these lead to myelin breakdown and demyelination. In some disorders, myelin sheath abnormalities are prominent but demyelination does not occur. This review explores the range of human and animal disorders where myelin pathology exists and focusses on defining the myelin changes in each and their cause, to help define whether they are targets for myelin repair therapy.

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We reviewed myelin disorders of the CNS in humans and animals.

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Myelin damage results from primary attack on the oligodendrocyte or myelin sheath.

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All major categories of disease can affect CNS myelin.

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Myelin vacuolation is common, yet does not always result in demyelination.

The common marmoset as an indispensable animal model for immunotherapy development in multiple sclerosis

New drugs often fail in the translation from the rodent experimental autoimmune encephalomyelitis (EAE) model to human multiple sclerosis (MS). Here, we present the marmoset EAE model as an indispensable model for translational research into MS. The genetic heterogeneity of this species and lifelong exposure to chronic latent infections and environmental pathogens create a human-like immune system. Unique to this model is the presence of the pathological hallmark of progressive MS, in particular cortical grey matter lesions. Another great possibility of this model is systemic and longitudinal immune profiling, whereas in humans and mice immune profiling is usually performed in a single compartment (i.e. blood or spleen, respectively). Overall, the marmoset model provides unique opportunities for systemic drug-effect profiling.

Neuroprotective effect of melatonin in experimental optic neuritis in rats

Optic neuritis (ON) is an inflammatory, demyelinating, and neurodegenerative condition of the optic nerve, which might induce permanent vision loss. Currently, there are no effective therapies for this disorder. We have developed an experimental model of primary ON in rats through a single microinjection of 4.5 μg of bacterial lipopolysaccharide (LPS) into the optic nerve. Since melatonin acts as a pleiotropic therapeutic agent in various neurodegenerative diseases, we analyzed the effect of melatonin on LPS-induced ON. For this purpose, LPS or vehicle were injected into the optic nerve from adult male Wistar rats. One group of animals received a subcutaneous pellet of 20 mg melatonin at 24 hr before vehicle or LPS injection, and another group was submitted to a sham procedure. Melatonin completely prevented the decrease in visual evoked potentials (VEPs), and pupil light reflex (PLR), and preserved anterograde transport of cholera toxin β-subunit from the retina to the superior colliculus. Moreover, melatonin prevented microglial reactivity (ED1-immunoreactivity, P < 0.01), astrocytosis (glial fibrillary acid protein-immunostaining, P < 0.05), demyelination (luxol fast blue staining, P < 0.01), and axon (toluidine blue staining, P < 0.01) and retinal ganglion cell (Brn3a-immunoreactivity, P < 0.01) loss, induced by LPS. Melatonin completely prevented the increase in nitric oxide synthase 2, cyclooxygenase-2 levels (Western blot) and TNFα levels, and partly prevented lipid peroxidation induced by experimental ON. When the pellet of melatonin was implanted at 4 days postinjection of LPS, it completely reversed the decrease in VEPs and PLR. These data suggest that melatonin could be a promising candidate for ON treatment.

High salt drives Th17 responses in experimental autoimmune encephalomyelitis without impacting myeloid dendritic cells

Recently, we have shown that high dietary salt intake aggravates T helper cell (Th) 17 responses and neuroinflammation. Here, we employed in vitro assays for myeloid dendritic cell (mDC) maturation, DC cytokine production, T cell activation and ex vivo analyses in murine experimental autoimmune encephalomyelitis (EAE) to investigate whether the salt effect on Th17 cells is further mediated through DCs in vivo. In cell culture, an excess of 40mM sodium chloride did neither affect the generation, maturation nor the function of DCs, but, in different assays, significantly increased Th17 differentiation. During the initiation phase of MOG35-55 EAE, we did not observe altered DC frequencies or co-stimulatory capacities in lymphoid organs, while IL-17A production and Th17 cells in the spleen were significantly increased. Complementary ex vivo analyses of the spinal cord during the effector phase of EAE showed increased frequencies of Th17 cells, but did not reveal differences in phenotypes of CNS invading DCs. Finally, adaption of transgenic mice harboring a MOG specific T cell receptor to a high-salt diet led to aggravated clinical disease only after active immunization. Wild-type mice adapted to a high-salt diet in the effector phase of EAE, bypassing the priming phase of T cells, only displayed mildly aggravated disease. In summary, our data argue for a direct effect of NaCl on Th17 cells in neuroinflammation rather than an effect primarily exerted via DCs. These data may further fuel our understanding on the dietary impact on different immune cell subsets in autoimmune diseases, such as multiple sclerosis.

Autoantibody-boosted T-cell reactivation in the target organ triggers manifestation of autoimmune CNS disease

Multiple sclerosis (MS) is caused by T cells that are reactive for brain antigens. In experimental autoimmune encephalomyelitis, the animal model for MS, myelin-reactive T cells initiate the autoimmune process when entering the nervous tissue and become reactivated upon local encounter of their cognate CNS antigen. Thereby, the strength of the T-cellular reactivation process within the CNS tissue is crucial for the manifestation and the severity of the clinical disease. Recently, B cells were found to participate in the pathogenesis of CNS autoimmunity, with several diverse underlying mechanisms being under discussion. We here report that B cells play an important role in promoting the initiation process of CNS autoimmunity. Myelin-specific antibodies produced by autoreactive B cells after activation in the periphery diffused into the CNS together with the first invading pathogenic T cells. The antibodies accumulated in resident antigen-presenting phagocytes and significantly enhanced the activation of the incoming effector T cells. The ensuing strong blood-brain barrier disruption and immune cell recruitment resulted in rapid manifestation of clinical disease. Therefore, myelin oligodendrocyte glycoprotein (MOG)-specific autoantibodies can initiate disease bouts by cooperating with the autoreactive T cells in helping them to recognize their autoantigen and become efficiently reactivated within the immune-deprived nervous tissue.

Exacerbation of experimental autoimmune encephalomyelitis in mice deficient for DCIR, an inhibitory C-type lectin receptor

Dendritic cell immunoreceptor (DCIR) is a C-type lectin receptor containing a carbohydrate recognition domain in its extracellular portion and an immunoreceptor tyrosine–based inhibitory motif, which transduces negative signals into cells, in its cytoplasmic portion. Previously, we showed that Dcir^–/– mice spontaneously develop autoimmune diseases such as enthesitis and sialadenitis due to excess expansion of dendritic cells (DCs), suggesting that DCIR is critically important for the homeostasis of the immune system. In this report, we analyzed the role of DCIR in the development of experimental autoimmune encephalomyelitis (EAE), an autoimmune disease model for multiple sclerosis. We found that EAE was exacerbated in Dcir^–/– mice associated with severe demyelination of the spinal cords. The number of infiltrated CD11c⁺ DCs and CD4⁺ T cells into spinal cords was increased in Dcir^–/– mice. Recall proliferative response of lymph node cells was higher in Dcir^–/– mice compared with wild-type mice. These observations suggest that DCIR is an important negative regulator of the immune system, and Dcir^–/– mice should be useful for analyzing the roles of DCIR in an array of autoimmune diseases.

Functional inflammatory profiles distinguish myelin-reactive T cells from patients with multiple sclerosis

Myelin-reactive T cells have been identified in patients with multiple sclerosis (MS) and healthy subjects with comparable frequencies, but the contribution of these autoreactive T cells to disease pathology remains unknown. A total of 13,324 T cell libraries generated from blood of 23 patients and 22 healthy controls were interrogated for reactivity to myelin antigens. Libraries derived from CCR6(+) myelin-reactive T cells from patients with MS exhibited significantly enhanced production of interferon-γ (IFN-γ), interleukin-17 (IL-17), and granulocyte-macrophage colony-stimulating factor (GM-CSF) compared to healthy controls. Single-cell clones isolated by major histocompatibility complex/peptide tetramers from CCR6(+) T cell libraries also secreted more proinflammatory cytokines, whereas clones isolated from controls secreted more IL-10. The transcriptomes of myelin-specific CCR6(+) T cells from patients with MS were distinct from those derived from healthy controls and, notably, were enriched in T helper cell 17 (TH17)-induced experimental autoimmune encephalitis gene signatures, and gene signatures derived from TH17 cells isolated other human autoimmune diseases. These data, although not causal, imply that functional differences between antigen-specific T cells from MS and healthy controls are fundamental to disease development and support the notion that IL-10 production from myelin-reactive T cells may act to limit disease progression or even pathogenesis.

Rotarod motor performance and advanced spinal cord lesion image analysis refine assessment of neurodegeneration in experimental autoimmune encephalomyelitis

BACKGROUND

Experimental autoimmune encephalomyelitis (EAE) is a commonly used experimental model for multiple sclerosis (MS). Experience with this model mainly comes from the field of immunology, while data on its use in studying the neurodegenerative aspects of MS is scarce.

NEW METHOD

The aim of this study is to improve and refine methods to assess neurodegeneration and function in EAE. Using the rotarod, a tool used in neuroscience to monitor motor performance, we evaluated the correlation between motor performance, disease severity as measured using a clinical scale and area covered by inflammatory lesions.

RESULTS

The included parameters are highly correlated in a non-linear manner, with motor performance rapidly decreasing in the intermediate values of the clinical scale. The relation between motor performance and histopathological damage is exclusively determined by lesions in the ventral and lateral columns, based on a new method of analysis of the entire spinal cord. Using a set of definitions for distinct disease milestones, we quantified disease duration as well as severity.

COMPARISON WITH EXISTING METHODS

The rotarod measures motor performance in a more objective and quantitative manner compared to using a clinical score. The outcome shows a strong correlation to the surface area of inflammatory lesions in the motor systems of the spinal cord.

CONCLUSIONS

These results provide an improved workflow for interpreting the outcome of EAE from a neurological point of view, with the eventual goal of dissecting neurodegeneration and evaluating neuroprotective drugs in EAE for application in MS.

Alternative source of stem cells derived from human periodontal ligament: a new treatment for experimental autoimmune encephalomyelitis

Background

Multiple sclerosis is a demyelinating disease mostly of autoimmune origin that affects and damages the central nervous system, leading to a disabling condition. The aim of the present study was to investigate whether administration of mesenchymal stem cells from human periodontal ligament (hPDLSCs) could ameliorate multiple sclerosis progression by exerting neuroprotective effects in an experimental model of autoimmune encephalomyelitis (EAE).

Methods

EAE was induced by immunization with myelin oligodendroglial glycoprotein peptide (MOG)_35–55 in C57BL/6 mice. After immunization, mice were observed every 48 hours for signs of EAE and weight loss. At the onset of disease, approximately 14 days after immunization, EAE mice were subjected to a single intravenous injection of hPDLSCs (10⁶ cells/150 μl) into the tail vein. At the point of animal sacrifice on day 56 after EAE induction, spinal cord and brain tissues were collected in order to perform histological evaluation, immunohistochemistry and western blotting analysis.

Results

Achieved results reveal that treatment with hPDLSCs may exert neuroprotective effects against EAE, diminishing both clinical signs and histological score typical of the disease (lymphocytic infiltration and demyelination) probably through the production of neurotrophic factors (results focused on brain-derived neurotrophic factor and nerve growth factor expression). Furthermore, administration of hPDLSCs modulates expression of inflammatory key markers (tumor necrosis factor-α, interleukin (IL)-1β, IL-10, glial fibrillary acidic protein, Nrf2 and Foxp3), the release of CD4 and CD8α T cells, and the triggering of apoptotic death pathway (data shown for cleaved caspase 3, p53 and p21).

Conclusions

In light of the achieved results, transplantation of hPDLSCs may represent a putative novel and helpful tool for multiple sclerosis treatment. These cells could have considerable implication for future therapies for multiple sclerosis and this study may represent the starting point for further investigations.

Neurologic autoimmunity: mechanisms revealed by animal models

Over the last decade, neurologic autoimmunity has become a major consideration in the diagnosis and management of patients with many neurologic presentations. The nature of the associated antibodies and their targets has led to appreciation of the importance of the accessibility of the target antigen to antibodies, and a partial understanding of the different mechanisms that can follow antibody binding. This chapter will first describe the basic principles of autoimmune inflammation and tissue damage in the central and peripheral nervous system, and will then demonstrate what has been learnt about neurologic autoimmunity from circumstantial clinical evidence and from passive, active, and occasionally spontaneous or genetic animal models. It will cover neurologic autoimmune diseases ranging from disorders of neuromuscular transmission, peripheral and ganglionic neuropathy, to diseases of the central nervous system, where autoantibodies are either pathogenic and cause destruction or changes in function of their targets, where they are harmless bystanders of T-cell-mediated tissue damage, or are not involved at all. Finally, this chapter will summarize the relevance of current animal models for studying the different neurologic autoimmune diseases, and it will identify aspects where future animal models need to be improved to better reflect the disease reality experienced by affected patients, e.g., the chronicity or the relapsing/remitting nature of their disease.