Induction Of Experimental Autoimmune Encephalomyelitis Research Articles

Multiple Sclerosis-Like Symptoms in Mice Are Driven by Latent γHerpesvirus-68 Infected B Cells.

Multiple sclerosis (MS) is caused by a combination of genetic and environmental factors. It is believed that previous infection with Epstein Barr Virus (EBV) plays an important role in the development of MS. Previously, we developed a murine model where latent infection with gamma herpesvirus 68 (γHV-68), a murine homolog to EBV, enhanced the symptoms of experimental autoimmune encephalomyelitis (EAE), resulting in disease that more closely resembles MS in humans. Here, we explored the conditions that were necessary for EAE enhancement. We showed that latently infected CD19+IgD− B cells were capable of enhancing EAE symptoms when transferred from mice previously infected with γHV-68 into uninfected mice. We also observed a prevention of enhancement when B cells were depleted before infection. However, depletion after the establishment of latency only partially reduced EAE. This indicated the existence of a mechanism where B cells play an important role as antigen presenting cells (APCs) prior to EAE induction for the priming of Th1 cells. It is possible that these signals persist even after B cell depletion, strongly suggesting a paracrine signaling modulation of non-B cell APCs. These results strongly support the concept that EBV contributes to the development of autoimmunity and highlights the need for a vaccine against EBV that could limit or prevent multiple sclerosis development.

Organic Selenium Reaches the Central Nervous System and Downmodulates Local Inflammation: A Complementary Therapy for Multiple Sclerosis?

Multiple sclerosis (MS) is an inflammatory and demyelinating disease of the central nervous system (CNS). The persistent inflammation is being mainly attributed to local oxidative stress and inflammasome activation implicated in the ensuing demyelination and axonal damage. Since new control measures remain necessary, we evaluated the preventive and therapeutic potential of a beta-selenium-lactic acid derivative (LAD-βSe), which is a source of organic selenium under development, to control experimental autoimmune encephalomyelitis (EAE) that is an animal model for MS. Two EAE murine models: C57BL/6 and SJL/J immunized with myelin oligodendrocyte glycoprotein and proteolipid protein, respectively, and a model of neurodegeneration induced by LPS in male C57BL/6 mice were used. The preventive potential of LAD-βSe was initially tested in C57BL/6 mice, the chronic MS model, by three different protocols that were started 14 days before or 1 or 7 days after EAE induction and were extended until the acute disease phase. These three procedures were denominated preventive therapy −14 days, 1 day, and 7 days, respectively. LAD-βSe administration significantly controlled clinical EAE development without triggering overt hepatic and renal dysfunction. In addition of a tolerogenic profile in dendritic cells from the mesenteric lymph nodes, LAD-βSe also downregulated cell amount, activation status of macrophages and microglia, NLRP3 (NOD-like receptors) inflammasome activation and other pro-inflammatory parameters in the CNS. The high Se levels found in the CNS suggested that the product crossed the blood-brain barrier having a possible local effect. The hypothesis that LAD-βSe was acting locally was then confirmed by using the LPS-induced neurodegeneration model that also displayed Se accumulation and downmodulation of pro-inflammatory parameters in the CNS. Remarkably, therapy with LAD-βSe soon after the first remitting episode in SJL/J mice, also significantly downmodulated local inflammation and clinical disease severity. This study indicates that LAD-βSe, and possibly other derivatives containing Se, are able to reach the CNS and have the potential to be used as preventive and therapeutic measures in distinct clinical forms of MS.

The Fabp5/calnexin complex is a prerequisite for sensitization of mice to experimental autoimmune encephalomyelitis.

We previously showed that calnexin (Canx)-deficient mice are desensitized to experimental autoimmune encephalomyelitis (EAE) induction, a model that is frequently used to study inflammatory demyelinating diseases, due to increased resistance of the blood-brain barrier to immune cell transmigration. We also discovered that Fabp5, an abundant cytoplasmic lipid-binding protein found in brain endothelial cells, makes protein-protein contact with the cytoplasmic C-tail domain of Canx. Remarkably, both Canx-deficient and Fabp5-deficient mice commonly manifest resistance to EAE induction. Here, we evaluated the importance of Fabp5/Canx interactions on EAE pathogenesis and on the patency of a model blood-brain barrier to T-cell transcellular migration. The results demonstrate that formation of a complex comprised of Fabp5 and the C-tail domain of Canx dictates the permeability of the model blood-brain barrier to immune cells and is also a prerequisite for EAE pathogenesis.

Anti-Axl antibody treatment reduces the severity of experimental autoimmune encephalomyelitis

BackgroundMultiple sclerosis is an immune-mediated disease of the central nervous system (CNS) characterized by inflammation, oligodendrocytes loss, demyelination, and damaged axons. Tyro3, Axl, and MerTK belong to a family of receptor tyrosine kinases that regulate innate immune responses and CNS homeostasis. During experimental autoimmune encephalomyelitis (EAE), the mRNA expression of MerTK, Gas6, and Axl significantly increase, whereas Tyro3 and ProS1 remain unchanged. We have shown that Gas6 is neuroprotective during EAE, and since Gas6 activation of Axl may be necessary for conferring neuroprotection, we sought to determine whether α-Axl or α-MerTK antibodies, shown by others to activate their respective receptors in vivo, could effectively reduce inflammation and neurodegeneration.MethodsMice received either α-Axl, α-MerTK, IgG isotype control, or PBS before the onset of EAE symptoms. EAE clinical course, axonal damage, demyelination, cytokine production, and immune cell activation in the CNS were used to determine the severity of EAE.Resultsα-Axl antibody treatment significantly decreased the EAE clinical indices of female mice during chronic EAE and of male mice during both acute and chronic phases. The number of days mice were severely paralyzed also significantly decreased with α-Axl treatment. Inflammatory macrophages/microglia and the extent of demyelination significantly decreased in the spinal cords of α-Axl-treated mice during chronic EAE, with no differences in the production of pro-inflammatory cytokines. α-MerTK antibody did not influence EAE induction or progression.ConclusionOur data suggests that the beneficial effect of Gas6/Axl signaling observed in mice administered with Gas6 can be partially preserved by administering an activating α-Axl antibody, but not α-MerTK.

Dicrocoelium ova can block the induction phase of experimental autoimmune encephalomyelitis.

This study aimed at investigating the impact of Dicrocoelium ova on experimental autoimmune encephalomyelitis (EAE) treatment in C57BL6 mice. Twenty-eight C57BL/6 mice were assigned into four groups as PBS, prophylaxis (P), treatment1 (T1) and treatment2 (T2). Prior to induction of EAE in prophylaxis group and on days 7 and 18 in T1 and T2 groups, respectively, Dicrocoelium eggs were injected intraperitoneally to each mouse. The clinical score, weight changes and incidence time of EAE were recorded. IFN-γ and IL-4 expression is quantified on spleen cells. Also, histopathological study by (H&E) and Toluidine-Blue (TB), and Luxol Fast Blue (LFB) were performed. The data were analysed using SPSS version 21. Mean disease scores were significantly lower in P and T1 groups than the PBS group (P=.01). IFN-γ was lower in P and T1 groups than the PBS group. The highest level of IL-4 was observed in T1 group. The total number of neuroglia cells of corpus callosum was similar in all groups, but the density increased in T1 group compared to the PBS group (P=.03). Dicrocoelium eggs have a great potential to stimulate immunomodulation towards treatment of EAE during the initial phase.

Modulation of experimental autoimmune encephalomyelitis through colonisation of the gut with Escherichia coli.

Multiple sclerosis (MS) is a neuro-inflammatory autoimmune disease of the central nervous system (CNS) that affects young adults. It is characterised by the development of demyelinating lesions and inflammation within the CNS. Although the causes of MS are still elusive, recent work using patient samples and experimental animal models has demonstrated a strong relationship between the gut microbiota and its contribution to CNS inflammation and MS. While there is no cure for MS, alteration of the gut microbiota composition through the use of probiotics is a very promising treatment. However, while most recent works have focused on the use of probiotics to modify pre-existing disease, little is known about its role in protecting from the establishment of MS. In this study, we determined whether colonisation with the probiotic bacterium Escherichia coli strain Nissle 1917 (EcN) could be used as a prophylactic strategy to prevent or alter the development of experimental autoimmune encephalomyelitis (EAE), a preclinical model of MS. We found that double gavage (two doses) of EcN before induction of EAE delayed disease onset and decreased disease severity. We also found that EcN-treated mice had decreased amounts of perivascular cuffing, CD4+ T cell infiltration into the CNS, together with significantly decreased absolute numbers of Th1 cells, and reduced activation of microglia. Although further studies are necessary to comprehend the exact protective mechanisms induced, our study supports a promising use of EcN as a probiotic for the prevention of MS.

The Helminth Parasite Heligmosomoides polygyrus Attenuates EAE in an IL-4Rα-Dependent Manner.

Helminth parasites are effective in biasing Th2 immunity and inducing regulatory pathways that minimize excessive inflammation within their hosts, thus allowing chronic infection to occur whilst also suppressing bystander atopic or autoimmune diseases. Multiple sclerosis (MS) is a severe autoimmune disease characterized by inflammatory lesions within the central nervous system; there are very limited therapeutic options for the progressive forms of the disease and none are curative. Here, we used the experimental autoimmune encephalomyelitis (EAE) model to examine if the intestinal helminth Heligmosomoides polygyrus and its excretory/secretory products (HES) are able to suppress inflammatory disease. Mice infected with H. polygyrus at the time of immunization with the peptide used to induce EAE (myelin-oligodendrocyte glycoprotein, pMOG), showed a delay in the onset and peak severity of EAE disease, however, treatment with HES only showed a marginal delay in disease onset. Mice that received H. polygyrus 4 weeks prior to EAE induction were also not significantly protected. H. polygyrus secretes a known TGF-β mimic (Hp-TGM) and simultaneous H. polygyrus infection with pMOG immunization led to a significant expansion of Tregs; however, administering the recombinant Hp-TGM to EAE mice failed to replicate the EAE protection seen during infection, indicating that this may not be central to the disease protecting mechanism. Mice infected with H. polygyrus also showed a systemic Th2 biasing, and restimulating splenocytes with pMOG showed release of pMOG-specific IL-4 as well as suppression of inflammatory IL-17A. Notably, a Th2-skewed response was found only in mice infected with H. polygyrus at the time of EAE induction and not those with a chronic infection. Furthermore, H. polygyrus failed to protect against disease in IL-4Rα−/− mice. Together these results indicate that the EAE disease protective mechanism of H. polygyrus is likely to be predominantly Th2 deviation, and further highlights Th2-biasing as a future therapeutic strategy for MS.

Enhanced expression of complement and microglial-specific genes prior to clinical progression in the MOG-experimental autoimmune encephalomyelitis model of multiple sclerosis

Understanding the biological changes responsible for failures in repair and the development of progressive MS is paramount for therapeutic intervention. In a well characterized experimental autoimmune encephalomyelitis (EAE) model of MS the clinical phenotype features an acute attack with partial recovery followed by a chronic or progressive disease phase. Neuropathology-focused gene expression profiles were generated from spinal cord, hindbrain and forebrain of mice 25 days after the induction of EAE, the time when recovery plateaus and transitions to a chronic or worsening phase. Differences in gene expression were most pronounced in the spinal cord of EAE mice compared to sham-immunized animals, with a subset of genes also found to be differentially expressed in the hindbrain and the forebrain, albeit with smaller fold-changes in expression. Our data suggests that changes in complement components, chemoattractant cytokines and especially enrichment in microglial cells may be the primary drivers of processes that limit recovery in EAE.

Amifostine ameliorates induction of experimental autoimmune encephalomyelitis: Effect on reactive oxygen species/NLRP3 pathway

Multiple sclerosis (MS) is an autoimmune disease for which conventional treatments have limited efficacy or side effects. Free radicals are primarily involved in blood–brain barrier disruption and induce neuronal and axonal damage, thus promoting the development of MS. Amifostine, a radioprotective drug used as a cytoprotective agent, attenuates oxidative stress and improves radiation damage by acting as a direct scavenger of reactive oxygen and nitrogen species. The aim of this study was to evaluate the effects of amifostine on MS in a mouse model of experimental autoimmune encephalomyelitis (EAE), which was developed by immunizing C57BL/6 mice with myelin oligodendrocyte glycoprotein and pertussis toxin. EAE mice received intraperitoneal injections of amifostine prior to onset of clinical symptoms and were monitored up to day 15 post induction. We observed abnormal clinical behavioral scores and a decrease in body weight. Histological analysis showed severe inflammatory infiltration and demyelination in the brain and spinal cord lumbar enlargements where significant upregulation of the mRNA expression of the pro-inflammatory cytokines interleukin-6 and interleukin-8, downregulation of the anti-inflammatory cytokine interleukin-10, and obvious microgliosis were also observed. Amifostine treatment potently reversed these abnormal changes. The anti-inflammatory effect of amifostine was associated with the inhibition of reactive oxygen species generation. Furthermore, the expression of proteins involved in the NLRP3 signaling pathway and pyroptosis was decreased. In conclusion, our study showed that amifostine ameliorates induction of experimental autoimmune encephalomyelitis via anti-inflammatory and anti-pyroptosis effects, providing further insights into the use of amifostine for the treatment of MS.

Rg3-enriched Korean Red Ginseng extract inhibits blood-brain barrier disruption in an animal model of multiple sclerosis by modulating expression of NADPH oxidase 2 and 4

BackgroundMultiple sclerosis (MS) and its animal model, the experimental autoimmune encephalomyelitis (EAE), are primarily characterized as dysfunction of the blood-brain barrier (BBB). Ginsenoside-Rg3-enriched Korean Red Ginseng extract (Rg3-KRGE) is known to exert neuroprotective, anti-inflammatory, and anti-oxidative effects on neurological disorders. However, effects of Rg3-KRGE in EAE remain unclear. MethodsHere, we investigated whether Rg3-KRGE may improve the symptoms and pathological features of myelin oligodendroglial glycoprotein (MOG)35-55 peptide – induced chronic EAE mice through improving the integrity of the BBB. ResultsRg3-KRGE decreased EAE score and spinal demyelination. Rg3-KRGE inhibited Evan's blue dye leakage in spinal cord, suppressed increases of adhesion molecule platelet endothelial cell adhesion molecule-1, extracellular matrix proteins fibronection, and matrix metallopeptidase-9, and prevented decreases of tight junction proteins zonula occludens-1, claudin-3, and claudin-5 in spinal cord following EAE induction. Rg3-KRGE repressed increases of proinflammatory transcripts cyclooxygenase-2, inducible nitric oxide synthase, interleukin (IL)-1 beta, IL-6, and tumor necrosis factor-alpha, but enhanced expression levels of anti-inflammatory transcripts arginase-1 and IL-10 in the spinal cord following EAE induction. Rg3-KRGE inhibited the expression of oxidative stress markers (MitoSOX and 4-hydroxynonenal), the enhancement of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase 2 (NOX2) and NOX4, and NADPH activity in the spinal cord of chronic EAE mice. Furthermore, apocynin, a NOX inhibitor, mimicked beneficial effects of Rg3-KRGE in chronic EAE mice. ConclusionOur findings suggest that Rg3-KRGE might alleviate behavioral symptoms and pathological features of MS by improving BBB integrity through modulation of NOX2/4 expression.

Shikonin ameliorates experimental autoimmune encephalomyelitis (EAE) via immunomodulatory, anti-apoptotic and antioxidative activity.

Multiple sclerosis is a common autoimmune inflammatory disease of the central nervous system. There are several underlying mechanisms for the pathogenesis of the disease, including inflammation, oligodendrocyteapoptosis and oxidative stress. The mechanism of action of shikonin was investigated in the C57BL/6 experimental autoimmune encephalomyelitis (EAE) model of multiple sclerosis. The results revealed that EAE induction significantly increased the extent of demyelination in the corpus callosum tissues of the animals, while treatment of the mice with shikonin significantly decreased the extent of demyelination. Real-time polymerase chain reaction-based analysis of the brain samples from the EAE mice revealed significant enhancement in the expression levels of tumour necrosis factor-α (TNF-α), interferon-γ (IFN-γ) and Bax genes as well as a reduction in the expression levels of transforming growth factor-ß (TGF-β) and Bcl2. But, shikonin treatment significantly reduced the expression levels of TNF-α, IFN-γ and Bax. On the other hand, the expression levels of TGF-β and Bcl2 as well as the activity of glutathione peroxidase-1 (GPX-1) enzyme were significantly increased following the shikonin treatment. This study emphasized the immune-modulatory and antioxidative effects of shikonin, which may have an important healing effect on the severity of EAE.

Gut microorganisms act together to exacerbate inflammation in spinal cords

Accumulating evidence indicates that gut microorganisms have a pathogenic role in autoimmune diseases, including in multiple sclerosis1. Studies of experimental autoimmune encephalomyelitis (an animal model of multiple sclerosis)2,3, as well as human studies4-6, have implicated gut microorganisms in the development or severity of multiple sclerosis. However, it remains unclear how gut microorganisms act on the inflammation of extra-intestinal tissues such as the spinal cord. Here we show that two distinct signals from gut microorganisms coordinately activate autoreactive T cells in the small intestine that respond specifically to myelin oligodendrocyte glycoprotein (MOG). After induction of experimental autoimmune encephalomyelitis in mice, MOG-specific CD4+ T cells are observed in the small intestine. Experiments using germ-free mice that were monocolonized with microorganisms from the small intestine demonstrated that a newly isolated strain in the family Erysipelotrichaceae acts similarly to an adjuvant to enhance the responses of T helper 17 cells. Shotgun sequencing of the contents of the small intestine revealed a strain of Lactobacillus reuteri that possesses peptides that potentially mimic MOG. Mice that were co-colonized with these two strains showed experimental autoimmune encephalomyelitis symptoms that were more severe than those of germ-free or monocolonized mice. These data suggest that the synergistic effects that result from the presence of these microorganisms should be considered in the pathogenicity of multiple sclerosis, and that further study of these microorganisms may lead to preventive strategies for this disease.

Olive Leaf Polyphenols Attenuate the Clinical Course of Experimental Autoimmune Encephalomyelitis and Provide Neuroprotection by Reducing Oxidative Stress, Regulating Microglia and SIRT1, and Preserving Myelin Integrity.

Numerous evidences suggest that plant polyphenols may have therapeutic benefits in regulating oxidative stress and providing neuroprotection in many neurodegenerative diseases, including multiple sclerosis (MS). However, these mechanisms are not yet completely understood. In this study, we investigated the effect of olive leaf polyphenols on oxidative stress through oxidation marker level and activity (TBARS, SOD, and GPX) and their protein expression (SOD1, SOD2, and GPX1), as well as the protein expression of Sirtuin 1 (SIRT1) and microglia markers (Iba-1, CD206, and iNOS) and myelin integrity (proteolipid protein expression) in the brain of rats with induced experimental autoimmune encephalomyelitis (EAE) and subjected to olive leaf therapy. Experiments were performed in male EAE DA rats, which were randomly divided into 2 main groups: EAE groups treated with the therapy of olive leaf (EAE+TOL) and untreated EAE control groups. The EAE treated groups consumed olive leaf tea instead of drinking water (ad libitum) from the beginning to the end of the experiment. In addition, olive leaf extract was injected intraperitoneally (i.p.) for the 10 continuous days and started on the 8th day after EAE induction. The clinical course was monitored in both groups until the 30th day after EAE induction. Our results demonstrated that TOL attenuated the clinical course of EAE; reduced the oxidative stress (by decreasing the concentration of MDA); upregulated antioxidant enzymes (SOD1, SOD2, and GPX1), SIRT1 (overall and microglial), and anti-inflammatory M2 microglia; downregulated proinflammatory M1 type; and preserved myelin integrity. These data support the idea that TOL may be an effective therapeutic approach for treating MS and other neurodegenerative diseases.

Prophylactic and Therapeutic Effects of MOG-Conjugated PLGA Nanoparticles in C57Bl/6 Mouse Model of Multiple Sclerosis.

Purpose: Multiple sclerosis (MS) is a debilitating neuroinflammatory disorder of the central nervous system. It is believed to result from an impaired immune response against myelin components especially myelin oligodendrocyte glycoprotein (MOG). Some efforts have been made to bioconjugate the MOG peptides to tolerogenic particles like poly (lactic-co-glycolic acid) (PLGA) for treating animal models of autoimmune disorders. Accordingly, we aimed to elucidate the tolerogenic effects of MOG-PLGA particles on experimental autoimmune encephalomyelitis (EAE).Methods: PGLA nanoparticles were synthesized using water/oil/water procedure. Next, the MOG or ovalbumin (OVA) peptides covalently linked to the PLGA particles. These particles were then intravenously or subcutaneously administered to nine groups of C57BL/6 mice before and after EAE induction. The brain tissues were assessed for the infiltration of immune cells. The Tolerogenic effect of the vaccine was also assessed on the quantity of the Treg cells. Moreover, the amount of interferon-γ (IFN-γ), interleukin-10 (IL-10), and interleukin-17 levels produced by splenic lymphocytes were then quantified by ELISA.Results: Intravenous administration of PLGA500-MOG35-55 nanoparticles before EAE induction ameliorated EAE clinical scores as well as infiltration of immune cells into the brain. In the spleen, the treatment increased CD4+CD25+FoxP3+ Treg population and restored the homeostasis of IFN-γ, IL-10, and IL-17 (all P values <0.0001) among splenocytes.Conclusion: The conjugation of MOG peptides to the PLGA nanoparticles significantly recovered clinical symptoms and the autoimmune response of EAE. The MOG-PGLA particles are potentially valuable for further evaluations, hopefully progressing toward an optimal approach that can be translated to the clinic.

Seasonal Variations in Macrophages/Microglia Underlie Changes in the Mouse Model of Multiple Sclerosis Severity.

Both immune and neurodegenerative mechanisms underlie multiple sclerosis (MS) and its animal model, experimental autoimmune encephalomyelitis (EAE). MS/EAE are triggered by encephalitogenic immune cells, including Th1 and Th17 cells, whereas T regulatory (Treg) cells are involved in inflammation resolution. Pro-inflammatory macrophages/microglia also play a deleterious role in the disease. Seasonal variations in MS relapses, active lesions, and pro- and anti-inflammatory cytokine levels have been described in MS patients and have been related with both perinatal and adult exposure to sunlight and other environmental factors. However, some data in EAE mice suggest that these variations might be, at least partially, endogenously determined. Thus, our objective was to study the effect of the season of birth and disease induction on the course of EAE, and immune cell infiltration in the central nervous system (CNS) in myelin oligodendrocyte glycoprotein (MOG35-55)-induced EAE in 8weeks old, female C57BL/6N mice maintained under constant, controlled conditions. EAE severity as well as pathogenic (Th1, Th17, macrophages/microglia) and protective (Treg) subsets was found to vary according to the season of birth or of EAE induction. Summer-born or summer-immunized animals developed a milder disease, which coincided with variations in numbers of T effector/regulatory subsets, and significantly low numbers of macrophages/microglia. These results suggest that endogenous rhythms in immune responses might cause seasonal variations in EAE severity, and, maybe, in the course of MS, and that they might be related to macrophages/microglia.

Systemic Mesenchymal Stem Cell Treatment Mitigates Structural and Functional Retinal Ganglion Cell Degeneration in a Mouse Model of Multiple Sclerosis.

PurposeThe purpose of this study was to determine mesenchymal stem cell (MSC) therapy efficacy on rescuing the visual system in the experimental autoimmune encephalomyelitis (EAE) model of multiple sclerosis (MS) and to provide new mechanistic insights.MethodsEAE was induced in female C57BL6 mice by immunization with myelin oligodendrocyte glycoprotein (MOG)35–55, complete Freund's adjuvant, and pertussis toxin. The findings were compared to sham-immunized mice. Half of the EAE mice received intraperitoneally delivered stem cells (EAE + MSC). Clinical progression was monitored according to a five-point EAE scoring scheme. Pattern electroretinogram (PERG) and retinal nerve fiber layer (RNFL) thickness were measured 32 days after induction. Retinas were harvested to determine retinal ganglion cell (RGC) density and prepared for RNA-sequencing.ResultsEAE animals that received MSC treatment seven days after EAE induction showed significantly lower motor-sensory impairment, improvement in the PERG amplitude, and preserved RNFL. Analysis of RNA-sequencing data demonstrated statistically significant differences in gene expression in the retina of MSC-treated EAE mice. Differentially expressed genes were enriched for pathways involved in endoplasmic reticulum stress, endothelial cell differentiation, HIF-1 signaling, and cholesterol transport in the MSC-treated EAE group.ConclusionsSystemic MSC treatment positively affects RGC function and survival in EAE mice. Better cholesterol handling by increased expression of Abca1, the cholesterol efflux regulatory protein, paired with the resolution of HIF-1 signaling activation might explain the improvements seen in PERG of EAE animals after MSC treatment.Translational RelevanceUsing MSC therapy in a mouse model of MS, we discovered previously unappreciated biochemical pathways associated with RGC neuroprotection, which have the potential to be pharmacologically targeted as a new treatment regimen.

N-Acylethanolamine Acid Amidase contributes to disease progression in a mouse model of multiple sclerosis

N-Acylethanolamine acid amidase (NAAA) deactivates the endogenous peroxisome proliferator-activated receptor-α (PPAR-α) agonist palmitoylethanolamide (PEA). NAAA-regulated PEA signaling participates in the control of peripheral inflammation, but evidence suggests also a role in the modulation of neuroinflammatory pathologies such as multiple sclerosis (MS). Here we show that disease progression in the mouse experimental autoimmune encephalomyelitis (EAE) model of MS is accompanied by induction of NAAA expression in spinal cord, which in presymptomatic animals is confined to motor neurons and oligodendrocytes but, as EAE progresses, extends to microglia/macrophages and other cell types. As previously reported for NAAA inhibition, genetic NAAA deletion delayed disease onset and attenuated symptom intensity in female EAE mice, suggesting that accrued NAAA expression may contribute to pathology. To further delineate the role of NAAA in EAE, we generated a mouse line that selectively overexpresses the enzyme in macrophages, microglia and other monocyte-derived cells. Non-stimulated alveolar macrophages from these NaaaCD11b+ mice contain higher-than-normal levels of inducible nitric oxide synthase and display an activated morphology. Furthermore, intranasal lipopolysaccharide injections cause greater alveolar leukocyte accumulation in NaaaCD11b+ than in control mice. NaaaCD11b+ mice also display a more aggressive clinical response to EAE induction, compared to their wild-type littermates. The results identify NAAA as a critical control step in EAE pathogenesis, and point to this enzyme as a possible target for the treatment of MS.

SIRPα on CD11c+ cells induces Th17 cell differentiation and subsequent inflammation in the CNS in experimental autoimmune encephalomyelitis.

Signal regulatory protein α (SIRPα) is expressed predominantly on type 2 conventional dendritic cells (cDC2s) and macrophages. We previously showed that mice systemically lacking SIRPα were resistant to experimental autoimmune encephalomyelitis (EAE). Here, we showed that deletion of SIRPα in CD11c+ cells of mice (SirpaΔDC mice) also markedly ameliorated the development of EAE. The frequency of cDCs and migratory DCs (mDCs), as well as that of Th17 cells, were significantly reduced in draining lymph nodes of SirpaΔDC mice at the onset of EAE. In addition, we found the marked reduction in the number of Th17 cells and DCs in the CNS of SirpaΔDC mice at the peak of EAE. Whereas inducible systemic ablation of SIRPα before the induction of EAE prevented disease development, that after EAE onset did not ameliorate the clinical signs of disease. We also found that EAE development was partially attenuated in mice with CD11c+ cell-specific ablation of CD47, a ligand of SIRPα. Collectively, our results suggest that SIRPα expressed on CD11c+ cells, such as cDC2s and mDCs, is indispensable for the development of EAE, being required for the priming of self-reactive Th17 cells in the periphery as well as for the inflammation in the CNS.

Swimming Exercise Ameliorates Symptoms of MOG-Induced Experimental Autoimmune Encephalomyelitis by Inhibiting Inflammation and Demyelination in Rats.

PurposeMultiple sclerosis is an autoimmune disease that affects the central nerve system, resulting in cumulative loss of motor function. Multiple sclerosis is induced through multiple mechanisms and is caused by inflammation and demyelination. This study aims to evaluate the neuroprotective effect of swimming exercise in experimental autoimmune encephalomyelitis (EAE) rats, an animal model of multiple sclerosis.MethodsEAE was induced by an intradermal injection of 50-μg purified myelin oligodendrocyte glycoprotein 33–55 (MOG33-55) dissolved in 200-μL saline at the base of the tail. The rats in the swimming exercise group were made to swim for 30 minutes once pert a day for 26 consecutive days, starting 5 days after induction of EAE. To compare the effect of swimming exercise with interferon-β, a drug for multiple sclerosis, interferon-β was injected intraperitoneally into rats of the EAE-induced and interferon-β-treated group during the exercise period.ResultsInjection of MOG33-55 caused weight loss, decreased clinical disability score, and increased level of pro-inflammatory cytokines and inflammatory mediators in the lumbar spinal cord. Loss of motor function and weakness increased demyelination score. Swimming exercise suppressed demyelination and expression of pro-inflammatory cytokines and inflammatory mediators. These changes promoted recovery of EAE symptoms such as body weight loss, motor dysfunction, and weakness. Swimming exercise caused the same level of improvement as interferon-β treatment.ConclusionsThe results of this experiment suggest the possibility of swimming exercise in urological diseases that are difficult to treat. Swimming exercises can be considered for relief of symptom in incurable multiple sclerosis.

A Clonal NG2-Glia Cell Response in a Mouse Model of Multiple Sclerosis.

NG2-glia, also known as oligodendrocyte precursor cells (OPCs), have the potential to generate new mature oligodendrocytes and thus, to contribute to tissue repair in demyelinating diseases like multiple sclerosis (MS). Once activated in response to brain damage, NG2-glial cells proliferate, and they acquire a reactive phenotype and a heterogeneous appearance. Here, we set out to investigate the distribution and phenotypic diversity of NG2-glia relative to their ontogenic origin, and whether there is a clonal NG2-glial response to lesion in an experimental autoimmune encephalomyelitis (EAE) murine model of MS. As such, we performed in utero electroporation of the genomic lineage tracer, StarTrack, to follow the fate of NG2-glia derived from single progenitors and to evaluate their response to brain damage after EAE induction. We then analyzed the dispersion of the NG2-glia derived clonally from single pallial progenitors in the brain of EAE mice. In addition, we examined several morphological parameters to assess the degree of NG2-glia reactivity in clonally-related cells. Our results reveal the heterogeneity of these progenitors and their cell progeny in a scenario of autoimmune demyelination, revealing the ontogenic phenomena at play in these processes.