Clinical Severity Of Experimental Autoimmune Encephalomyelitis Research Articles

Hyperforin-loaded gold nanoparticle alleviates experimental autoimmune encephalomyelitis by suppressing Th1 and Th17 cells and upregulating regulatory T cells

Hyperforin an herbal compound, is commonly used in traditional medicine due to its anti-inflammatory activities. The aim of this study was to use a hyperforin loaded gold nanoparticle (Hyp-GNP) in the treatment of experimental autoimmune encephalomyelitis (EAE) an animal model of multiple sclerosis (MS). Hyp-GNP and hyperforin significantly reduced clinical severity of EAE, which was accompanied by a decrease in the number of inflammatory cell infiltration in the spinal cord. Additionally, treatment with Hyp-GNP significantly inhibited disease-associated cytokines as well as an increase in the anti-inflammatory cytokines in comparison to all groups including the free-hyp group. Furthermore, hyperforin and Hyp-GNP inhibited the differentiation of Th1 and Th17 cells while promoting Treg and Th2 cell differentiation via regulating their master transcription factors. The current study demonstrated the although, free-hyp improved clinical and laboratory data Hyp-GNP is significantly more efficient than free hyperforin in the treatment of EAE.

Changes of synapses in experimental autoimmune encephalomyelitis by using Fasudil.

The ROCK signaling pathway is involved in numerous fundamental cellular functions such as cell migration, apoptosis, inflammatory responses, and neurite outgrowth. Previous studies demonstrate that Fasudil exhibited therapeutic potential of experimental autoimmune encephalomyelitis (EAE) possibly through immune-modulation and anti-inflammation. In this study, we observed the effect of Fasudil on synaptic protection of EAE mice. Fasudil ameliorated the clinical severity of EAE and inhibited Rho kinase (ROCK), especially ROCK II, in brain and spinal cord of EAE mice. Protein extracts from spinal cord of Fasudil-treated EAE mice promoted the formation of neurite outgrowth when co-cultured with primary neurons, indicating that peripheral administration of Fasudil can enter the central nervous system (CNS) and exhibited its biological effect on the formation of neurite outgrowth. Synapse-related molecule synaptophysin was enhanced, and CRMP-2, AMPA receptor, and GSK-3β were declined in spinal cord of Fasudil-treated mice. Neurotrophic factor BDNF and GDNF as well as immunomodulatory cytokine IL-10 in spinal cord were elevated in Fasudil-treated mice, while inflammatory cytokine IL-17, IL-1β, IL-6, and TNF-α were obviously inhibited, accompanied by the decrease of inflammatory M1 iNOS and the increase of anti-inflammatory M2 Arg-1, providing a microenvironment that contributes to synaptic protection. Our results indicate that Fasudil treatment protected against synaptic damage and promoted synaptic formation, which may be related with increased neurotrophic factors as well as decreased inflammatory microenvironment in the CNS of EAE mice.

1,25-Dihydroxyvitamin D3 Protects against Immune-Mediated Killing of Neurons in Culture and in Experimental Autoimmune Encephalomyelitis.

Several studies have reported that low vitamin D levels are associated with an increased risk of developing multiple sclerosis (MS). As MS is an inflammatory disorder with degeneration of axons and neurons, we examined whether the biologically active form of vitamin D, 1,25-dihydroxyvitamin D3 (1,25D3), could protect against the T cell-mediated killing of human neurons in culture, and the axonal loss seen in mice with experimental autoimmune encephalomyelitis (EAE). Human neurons were exposed to activated human T lymphocytes and the loss of neurons was documented 24 hours later by counting the number of microtubule-associated protein-2 positive cells. Mice with EAE were harvested for counts of axonal profiles in the spinal cord. 1,25D3 was exposed to T cells in culture or administered to mice from peak EAE clinical severity when axonal loss was already evolving. Activated T lymphocytes killed human neurons prominently within 24 hours but toxicity was significantly attenuated when T cells were exposed to 1,25D3 prior to the co-culture. In EAE, 1,25D3 treatment initiated from peak clinical severity reduced the extent of clinical disability and mitigated the progressive loss of axons. The reduction of axonal and neuronal loss by 1,25D3 in the context of an inflammatory assault to the central nervous system is a potential contributor to the putative benefits of vitamin D in MS.

Protective effects of matrine on experimental autoimmune encephalomyelitis via regulation of ProNGF and NGF signaling

Inflammation, demyelination, oligodendrocyte (OLG) death, and axonal degeneration are primary characteristics of multiple sclerosis (MS) and its animal model, experimental autoimmune encephalomyelitis (EAE). OLGs generate myelin sheaths that surround axons, while damage to OLGs leads to demyelination and neurological functional deficit. Matrine (MAT), a quinolizidine alkaloid derived from the herb Radix Sophorae Flave, has been recently found to effectively ameliorate clinical signs in EAE. Its therapeutic mechanism has, however, not been completely elucidated. In the present study, we found that MAT retarded the disease process, attenuated the clinical severity of EAE rats, ameliorated inflammation and demyelination, and suppressed the apoptosis of OLGs in the central nervous system (CNS) of EAE rats. In addition, MAT markedly blocked increased expression of the proNGF-p75NTR death signaling complex, which is known to mediate OLG death in EAE animals. At the same time, MAT also prevented a decrease in the levels of NGF and its receptor TrkA, which together mediate the cell survival pathway and differentiation of OLGs. ProNGF, NGF, and the downstream effector proteins play an important role in the growth, differentiation, and apoptosis of OLGs as well as the reparative response to neuronal damage. These findings thus indicate that MAT improves clinical severity of EAE in part by reducing OLG apoptosis via restoring the ratios of proNGF:NGF and the respective receptors p75NTR:TrkA in vivo. Taken together, these results suggest that MAT may be a promising agent for MS treatment based on its protective effect on OLGs.

CXCR7 suppression modulates microglial chemotaxis to ameliorate experimentally-induced autoimmune encephalomyelitis

Multiple sclerosis (MS) is the prototypical inflammatory demyelinating disease of the central nervous system (CNS). Experimental autoimmune encephalomyelitis (EAE), widely used as an animal model of MS, classically manifests as an ascending paralysis that is characterized by extensive infiltration of the CNS by inflammatory cells. Although several studies uncover the significant role of microglia in the development of EAE, the cellular mechanisms of microglia that govern EAE pathogenesis remain unknown. In the current study, we report that CXCR7 expression is dynamic regulated in activated microglia during CNS autoimmunity and positively correlates with the clinical severity of EAE. In addition, microglial chemotaxis is mediated by CXCR7 during CNS autoimmunity, signaling through extracellular signal-regulated kinase (ERK)1/2 activation, whereas p38 mitogen-activated protein kinase (MAPK) and (c-Jun N-terminal kinase) JNK are not involved. Most importantly, CXCR7 neutralizing treatment ameliorates the clinical severity of EAE along with ERK1/2 phosphorylation reduction. Collectively, our data demonstrate that CXCR7 suppression modulates microglial chemotaxis to ameliorate EAE.

The immunoregulatory effect of Rho kinase inhibitor Fasudil on macrophages in a mouse model of experimental autoimmune encephalomyelitis

Objective To investigate the immunoregulatory effect of Fasudil-modified macrophages on cell transferred experimental autoimmune encephalomyelitis (EAE) in a mouse model. Methods Female C57BL/6 mice were immunized with MOG35-55 to establish the model of EAE. The encephalomyelitic mononuclear cells (MNCs) were isolated from spleen of mice with EAE on day 9 after immunization and treated with or without Fasudil for 72 h in vitro. Several assays including the flow cytometry analysis, Griess reaction and ELISA were performed to analyze the M1 and M2 phenotypes of macrophages, the production of NO and the levels of cytokines, respectively. The cultured MNCs (5×107 cells) were resuspended in 500 μl of PBS and transferred into naive C57BL/6 recipients via intraperitoneal injection. Two groups including the PBS-MNCs group and the Fasudil-MNCs group were set up. The body weights and clinical scores of the mice in each group were recorded in every other days after the induction of EAE in the recipients. Results The Fasudil treated MNCs affected the induction of EAE in adoptive cell transferred mice. The expression of CD16/32, iNOS and IL-12 on F4/80-macrophages were decreased, while the expression of CD206, CD23 and IL-10 on F4/80-macrophages were increased upon the treatment of Fasudil, indicating that Fasudil improved the differentiation of macrophages from M1 to M2 phenotypes. Moreover, Fasudil inhibited the production of NO and enhanced the expression of Arginase-1. Conclusion Fasudil ameliorated the clinical severity of EAE in mice by promoting the transformation of macrophages from M1 to M2 phenotype. Key words: Fasudil; Experimental autoimmune encephalomyelitis; Macrophage; Anti-inflammation

Inhibition of matrix metalloproteinase-9 reduces clinical severity in a murine model of multiple sclerosis. (THER7P.944)

Abstract Matrix metalloproteinases (MMPs) are a family of proteolytic enzymes that mediate the degradation of various components of the extracellular matrix. Their functions are essential for normal physiological processes such as wound healing, but their dysregulation is associated with various pathologies including autoimmune diseases such as Multiple Sclerosis (MS). Experimental Autoimmune Encephalomyelitis (EAE) is a well-established murine model of MS that is mediated by CD4+ T-cells. These cells penetrate the blood-brain-barrier (BBB), recruit other immune cells, initiate destruction of the myelin sheath, and cause axonal loss. MMP-9 is a hallmark enzyme in the progression of MS that is required for penetration of the BBB and generation of autoantigens in EAE. In addition, recent studies have demonstrated that MMP-9 contributes to normal intracellular function of various cell types including antigen activated T-cells; however, the intracellular role of MMP-9 in immune cell activation during EAE pathogenesis is not known. In this study, we used a highly selective MMP-9 triple-helical peptide inhibitor (THPI) that is a phosphinate transition state analog to examine antigen specific T-cell responses. We found that selective inhibition of MMP-9 can mitigate pathogenic T-cell activity and cellular trafficking as well as the clinical severity of EAE, suggesting that selective MMP-9 inhibition in MS can be a potent therapeutic option.

MicroRNA-21 promotes Th17 differentiation and mediates experimental autoimmune encephalomyelitis.

Accumulation of IL-17-producing Th17 cells is associated with the development of multiple autoimmune diseases; however, the contribution of microRNA (miRNA) pathways to the intrinsic control of Th17 development remains unclear. Here, we demonstrated that miR-21 expression is elevated in Th17 cells and that mice lacking miR-21 have a defect in Th17 differentiation and are resistant to experimental autoimmune encephalomyelitis (EAE). Furthermore, we determined that miR-21 promotes Th17 differentiation by targeting and depleting SMAD-7, a negative regulator of TGF-β signaling. Moreover, the decreases in Th17 differentiation in miR-21-deficient T cells were associated with defects in SMAD-2/3 activation and IL-2 suppression. Finally, we found that treatment of WT mice with an anti-miR-21 oligonucleotide reduced the clinical severity of EAE, which was associated with a decrease in Th17 cells. Thus, we have characterized a T cell-intrinsic miRNA pathway that enhances TGF-β signaling, limits the autocrine inhibitory effects of IL-2, and thereby promotes Th17 differentiation and autoimmunity.

54: Helminth-induced innate type-2 cytokines protect against autoimmunity

Helminth parasites typically establish chronic infections in the mammalian host which can persist for decades. Helminths evade protective host immune responses by promoting innate and adaptive anti-inflammatory networks which can also suppress immune responses to unrelated antigens. Indeed, it has been shown parasitic infection of humans is associated with a lower incidence of allergy and autoimmune disease in rural areas of the developing world. Experimental models of autoimmunity have revealed that helminth-induced protection against disease can be mediated by the action of either Treg or Th2 cells [1] . Here we examined the immunoregulatory effects of the excretory-secretory (ES) products of the helminth parasite, Fasciola hepatica, in the mouse model of multiple sclerosis, experimental autoimmune encephalomyelitis (EAE). Administration of ES delayed the onset and attenuated the clinical severity of EAE which was associated with a decreased production of auto antigen-specific IFN- γ and IL-17. Unexpectedly, IL-10, TGF- β , or regulatory T cells did not play a role in the ES-induced attenuation of disease. Moreover, ES-elicited T cells did not suppress EAE and protection from disease was also retained in IL-4-deficient mice, suggesting that Th2 cells do not play a role in ES-induced amelioration of EAE. However adoptive transfer of macrophages or eosinophils, from ES-treated mice transferred protection. Furthermore, IL-5, a cytokine which mediates eosinophilia in vivo, was required for ES-induced protection against EAE. We are currently investigating the role of the epithelial cell-derived ‘alarmin’ cytokine, IL-33, in mediating the regulatory effects of ES. We have determined that IL-33 acts on mast cells to promote the alternative activation of macrophages with regulatory capacity while also promoting eosinophilia in vivo. These findings provide new insights into how helminths target innate immune cells in order to modulate the immune response thereby inhibiting the Th1 and Th17 responses that mediate inflammatory disease.

Intranasal delivery of FSD-C10, a novel Rho kinase inhibitor, exhibits therapeutic potential in experimental autoimmune encephalomyelitis.

Viewing multiple sclerosis (MS) as both neuroinflammation and neurodegeneration has major implications for therapy, with neuroprotection and neurorepair needed in addition to controlling neuroinflammation in the central nervous system (CNS). While Fasudil, an inhibitor of Rho kinase (ROCK), is known to suppress experimental autoimmune encephalomyelitis (EAE), an animal model of MS, it relies on multiple, short-term injections, with a narrow safety window. In this study, we explored the therapeutic effect of a novel ROCK inhibitor FSD-C10, a Fasudil derivative, on EAE. An important advantage of this derivative is that it can be used via non-injection routes; intranasal delivery is the preferred route because of its efficient CNS delivery and the much lower dose compared with oral delivery. Our results showed that intranasal delivery of FSD-C10 effectively ameliorated the clinical severity of EAE and CNS inflammatory infiltration and promoted neuroprotection. FSD-C10 effectively induced CNS production of the immunoregulatory cytokine interleukin-10 and boosted expression of nerve growth factor and brain-derived neurotrophic factor proteins, while inhibiting activation of p-nuclear factor-κB/p65 on astrocytes and production of multiple pro-inflammatory cytokines. In addition, FSD-C10 treatment effectively induced CD4(+) CD25(+) , CD4(+) FOXP3(+) regulatory T cells. Together, our results demonstrate that intranasal delivery of the novel ROCK inhibitor FSD-C10 has therapeutic potential in EAE, through mechanisms that possibly involve both inhibiting CNS inflammation and promoting neuroprotection.

Thrombin mutant W215A/E217A treatment improves neurological outcome and attenuates central nervous system damage in experimental autoimmune encephalomyelitis.

Multiple sclerosis (MS) is a neuroinflammatory disease characterized by demyelination and axonal damage of the central nervous system. The pathogenesis of MS has also been linked to vascular inflammation and local activation of the coagulation system, resulting in perivascular fibrin deposition. Treatment of experimental autoimmune encephalomyelitis (EAE), a model of human MS, with antithrombotic and antiinflammatory activated protein C (APC) reduces disease severity. Since recombinant APC (Drotecogin alfa), originally approved for the treatment of severe sepsis, is not available for human MS studies, we tested the hypothesis that pharmacologic activation of endogenous protein C could likewise improve the outcome of EAE. Mice were immunized with murine myelin oligodendrocyte glycoprotein (MOG) peptides and at the onset of EAE symptoms, were treated every other day with either WE thrombin (25 μg/kg; i.v.), a selective recombinant protein C activator thrombin analog, or saline control. Mice were monitored for changes in disease score until euthanized for ex vivo analysis of inflammation. Administration of WE thrombin significantly ameliorated clinical severity of EAE, reduced inflammatory cell infiltration and demyelination, suppressed the activation of macrophages comprising the CD11b + population and reduced accumulation of fibrin (ogen) in the spinal cord. These data suggest that symptomatic MS may respond to a treatment strategy that involves temporal pharmacological enhancement of endogenous APC generation.

Apolipoprotein E mediation of neuro-inflammation in a murine model of multiple sclerosis

Apolipoprotein E (ApoE) functions as a ligand in receptor-mediated endocytosis of lipoprotein particles and has been demonstrated to play a role in antigen presentation. To explore the contribution of ApoE during autoimmune central nervous system (CNS) demyelination, we examined the clinical, cellular immune function, and pathologic consequences of experimental autoimmune encephalomyelitis (EAE) induction in ApoE knockout (ApoE−/−) mice. We observed reduced clinical severity of EAE in ApoE−/− mice in comparison to WT mice that was concomitant with an early reduction of dendritic cells (DCs) followed by a reduction of additional innate cells in the spinal cord at the peak of disease without any differences in axonal damage. While T cell priming was enhanced in ApoE−/− mice, reduced severity of EAE was also observed in ApoE−/− recipients of encephalitogenic wild type T cells. Expression of ApoE during EAE was elevated within the CNS of wild type mice, particularly by innate cells such as DCs. Overall, ApoE promotes clinical EAE, likely by mediation of inflammation localized within the CNS.

Uncovering Cryptic Glycan Markers in Multiple Sclerosis (MS) and Experimental Autoimmune Encephalomyelitis (EAE)

Using an integrated antigen microarray approach, we observed epitope-spreading of autoantibody responses to a variety of antigenic structures in the cerebrospinal fluid (CSF) of patients with multiple sclerosis (MS) and in the serum of mice with experimental autoimmune encephalomyelitis (EAE). These included previously described protein- and lipid-based antigenic targets and newly discovered autoimmunogenic sugar moieties, notably, autoantibodies specific for the oligomannoses in both MS patient CSF and the sera of mice with EAE. These glycans are often masked by other sugar moieties and belong to a class of cryptic autoantigens. We further determined that these targets are highly expressed on multiple cell types in MS and EAE lesions. Co-immunization of SJL/J mice with a Man9-KLH conjugate at the time of EAE induction elicited highly significant levels of anti-Man9-cluster autoantibodies. Nevertheless, this anti-glycan autoantibody response was associated with a significantly reduced clinical severity of EAE. The potential of these cryptic glycan markers and targeting antibodies for diagnostic and therapeutic interventions of neurological disorders has yet to be explored.

97 : Silencing MicroRNA-21 ameliorates Th17 mediated autoimmune inflammation

IL-17 producing Th17 cells are the key participants in various autoimmune diseases including multiple sclerosis (MS) and its animal model, experimental autoimmune encephalomyelitis (EAE). Although differentiation of Th17 cells are known to be regulated by specific transcription factors and cytokines, the role of microRNAs that control this inflammatory T cell subset and whether targeting microRNAs can have therapeutic effects are not understood well. We found that microRNA-21 expression is elevated in Th17 cells and Mir-21-/- mice show a defect in Th17 differentiation and are resistant to EAE. Mir-21-/- T cells fail to induce known factors required for Th17 differentiation, such as transcription factor RORgt and the cytokine IL-21. However, Mir-21-/- mice have normal Th1, Th2 and Treg differentiation. The T cell intrinsic function of Mir-21 was clearly demonstrated by the sensitivity to EAE of the Mir-21-/- mice into which WT CD4+ T cells were transferred. Mir-21 promoted Th17 differentiation by targeting Smad-7, a negative regulator of TGF-beta signaling and Th17 differentiation. Finally, we found that anti-Mir-21 treatment reduced clinical severity of EAE associated with decrease in Th17 cells. These findings demonstrate that Mir-21 confers susceptibility to EAE by affecting inflammatory Th17 responses and identify Mir-21 as a new target for therapeutic intervention in MS.

Reduction of microglial activity in a model of multiple sclerosis by dipyridamole

BackgroundDespite extensive and persistent activation of microglia in multiple sclerosis (MS), microglia inhibitors have not yet been identified for treatment of the disorder. We sought to identify medications already in clinical use that could inhibit the activation of microglia. On the basis of the reported inhibitory effects of dipyridamole on phosphodiesterase activity that result in the production of various anti-inflammatory outcomes, we selected it for study. Dipyridamole is used clinically for secondary prevention in stroke. In this study, dipyridamole was examined using microglia in culture and in the mouse model of MS, experimental autoimmune encephalomyelitis (EAE).ResultsWe found that dipyridamole attenuated the elevation of several cytokines and chemokines in human microglia caused by Toll-like receptor stimulation. Morphological characteristics of activated microglia in culture were also normalized by dipyridamole. In mice, dipyridamole decreased the clinical severity of EAE and reduced microglial activity and other histological indices of EAE in the spinal cord.ConclusionsDipyridamole is an inhibitor of microglia activation and may have a role in MS and other neurological conditions to attenuate microglial activity.

Fms-like tyrosine kinase 3 ligand-Fc chimera suppresses autoimmune demyelinating disease (P5228)

Abstract Dendritic cells (DC) are versatile immune cells that can promote protective anti-pathogen immunity or dampen destructive autoimmune responses. Fms-like tyrosine kinase 3-ligand (FLT3L) signals through the FLT3 receptor to drive DC differentiation and proliferation. We generated a novel mouse-FLT3L—human-FC-domain (FLT3L-FC) fusion construct that, when combined with hydrodynamic gene delivery (HDT), induces robust DC expansion in vivo. In particular, FLT3L-FC HDT induced expansion of surface marker-defined tolerogenic DC subsets. Given the central role of DC in the pathogenesis of experimental autoimmune encephalomyelitis (EAE), a mouse model of multiple sclerosis (MS), we investigated the action of FLT3L-FC in EAE. Prophylactic treatment of mice with FLT3L-FC HDT (a single i.v. injection of 10 ug of plasmid DNA) significantly suppressed the onset and clinical severity of EAE, and significantly reduced the number of inflammatory foci in CNS parenchyma. FLT3L-FC HDT in EAE mice induced expansion of peripheral (spleen) and CNS-infiltrating tolerogenic DC, as well as peripheral CD4+ regulatory T cells (Tregs), which we speculate underlies the cellular mechanism of EAE suppression by FLT3L. Our results therefore support the emerging paradigm that the fundamental action of FLT3L in vivo is immune suppression.

Targeting the Shift from M1 to M2 Macrophages in Experimental Autoimmune Encephalomyelitis Mice Treated with Fasudil

We observed the therapeutic effect of Fasudil and explored its mechanisms in experimental autoimmune encephalomyelitis (EAE), an animal model of multiple sclerosis (MS). Fasudil, a selective Rho kinase (ROCK) inhibitor, was injected intraperitoneally at 40 mg/kg/d in early and late stages of EAE induction. Fasudil ameliorated the clinical severity of EAE at different stages, and decreased the expression of ROCK-II in spleen, accompanied by an improvement in demyelination and inhibition of inflammatory cells. Fasudil mainly inhibited CD4+IL-17+ T cells in early treatment, but also elevated CD4+IL-10+ regulatory T cells and IL-10 production in late treatment. The treatment of Fasudil shifted inflammatory M1 to anti-inflammatory M2 macrophages in both early and late treatment, being shown by inhibiting CD16/32, iNOS, IL-12, TLR4 and CD40 and increasing CD206, Arg-1, IL-10 and CD14 in spleen. By using Western blot and immunohistochemistry, iNOS and Arg-1, as two most specific markers for M1 and M2, was inhibited or induced in splenic macrophages and spinal cords of EAE mice treated with Fasudil. In vitro experiments also indicate that Fasudil shifts M1 to M2 phenotype, which does not require the participation or auxiliary of other cells. The polarization of M2 macrophages was associated with the decrease of inflammatory cytokine IL-1β, TNF-α and MCP-1. These results demonstrate that Fasudil has therapeutic potential in EAE possibly through inducing the polarization of M2 macrophages and inhibiting inflammatory responses.

Estrogen treatment prevents gray matter atrophy in experimental autoimmune encephalomyelitis

Gray matter atrophy is an important correlate to clinical disability in multiple sclerosis (MS), and many treatment trials include atrophy as an outcome measure. Atrophy has been shown to occur in experimental autoimmune encephalomyelitis (EAE), the most commonly used animal model of MS. The clinical severity of EAE is reduced in estrogen-reated mice, but it remains unknown whether estrogen treatment can reduce gray matter atrophy in EAE. In this study, mice with EAE were treated with either estrogen receptor (ER)-α ligand or ER-β ligand, and diffusion tensor images (DTI) were collected and neuropathology was performed. DTI showed atrophy in the cerebellar gray matter of vehicle-treated EAE mice compared with healthy controls but not in ER-α or ER-β ligand-treated EAE mice. Neuropathology demonstrated that Purkinje cell numbers were decreased in vehicle-treated EAE mice, whereas neither ER ligand-treated EAE groups showed a decrease. This is the first report of a neuroprotective therapy in EAE that unambiguously prevents gray matter atrophy while sparing a major neuronal cell type. Fractional anisotropy (FA) in the cerebellar white matter was decreased in vehicle- and ER-β ligand-treated but not in ER-α ligand-treated EAE mice. Inflammatory cell infiltration was increased in vehicle- and ER-β ligand-treated but not in ER-α ligand-treated EAE mice. Myelin staining was decreased in vehicle-treated EAE mice and was spared in both ER ligand-treated groups. This is consistent with decreased FA as a potential biomarker for inflammation rather than myelination or axonal damage in the cerebellum in EAE.

Disruption of NMDA Receptors in Oligodendroglial Lineage Cells Does Not Alter Their Susceptibility to Experimental Autoimmune Encephalomyelitis or Their Normal Development

Pharmacological studies have suggested that oligodendroglial NMDA glutamate receptors (NMDARs) mediate white matter injury in a variety of CNS diseases, including multiple sclerosis (MS). We tested this hypothesis in experimental autoimmune encephalomyelitis (EAE), a model of human MS, by timed conditional disruption of oligodendroglial NR1, an essential subunit of functional NMDARs, using an inducible proteolipid protein (Plp) promoter-driven Cre-loxP recombination system. We found that selective ablation of oligodendroglial NR1 did not alter the clinical severity of EAE elicited in C57BL/6 mice by immunization with myelin oligodendrocyte glycoprotein peptide 35-55 (MOG-peptide), nor were there significant differences between the oligodendroglial NR1 KO and non-KO mice in numbers of axons lost in spinal cord dorsal funiculi or severity of spinal cord demyelination. Similarly, constitutive deletion of NR3A, a modulatory subunit of oligodendroglial NMDARs, did not alter the course of MOG-peptide EAE. Furthermore, conditional and constitutive ablation of NR1 in neonatal oligodendrocyte progenitor cells did not interrupt their normal maturation and differentiation. Collectively, our data suggest that oligodendroglial lineage NMDARs are neither required for timely postnatal development of the oligodendroglial lineage, nor significant participants in the pathophysiology of MOG-peptide EAE.

Targeting CB 2 receptor as a neuroinflammatory modulator in experimental autoimmune encephalomyelitis

During immune mediated demyelinating lesions, the endocannabinoid system is involved in the pathogenesis of both neuroinflammation and neurodegeneration through different mechanisms. Here, we explored the cellular distribution of cannabinoid 2 receptor (CB 2R) in the central nervous system (CNS) and detected the level of CB 2R expression during experimental autoimmune encephalomyelitis (EAE) by RT-PCR, Western blot and immunostaining. Our results show that CB 2R was expressed in neurons, microglia and astrocytes. During EAE, the expression of CB 2R in spinal cord rose slowly at days 9 and 17 post immunization (p.i.), and elevated rapidly at day 28 p.i., while the expression of CB 2R in spleen elevated rapidly and got a plateau at days 17 and 28 p.i. Only the increase of CB 2R expression in spinal cord demonstrated a significant difference when compared to control mice immunized with complete Freund's adjuvant (CFA). The selective CB 2R antagonist (SR144528) exacerbated EAE clinical severity accompanied by weight loss. SR144528 inhibited the expression of CB 2R, but increased the expression of CB 1R in brain, spinal cord and spleen. The administration of SR144528 declined interferon-γ, IL-17, IL-4, IL-10, IL-1β, IL-6 and tumor necrosis factor-α, but increased CX3CL1 in brain and/or spinal cord. In contrast, IL-17 and MCP-1 were increased, while CX3CL1 was decreased in splenic mononuclear cells as compared to vehicle controls. These results indicate that manipulation of CB 2R may have therapeutic value in MS, but its complexity remains to be considered and studied for further clinical application.