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Objectives The intestinal microflora affects the pathogenesis of several autoimmune diseases by influencing immune system function. Some bacteria, such as lactic acid bacteria, have been reported to have beneficial effects on immune function. However, little is known about the effects of yeasts. Here, we aimed to investigate the effects of various dietary yeasts contained in fermented foods on experimental autoimmune encephalomyelitis (EAE), an animal model of multiple sclerosis (MS), and to elucidate the mechanisms underlying these effects. Methods The effects of eight yeasts selected from 18 types of yeasts contained in fermented foods were examined using an EAE model. Of these, Candida kefyr was investigated by analyzing the intestinal microflora and its effects on intestinal and systemic immune states. Results Administration of C. kefyr ameliorated the severity of EAE. Reduced numbers of Th17 cells, suppressed interleukin (IL)-6 production by intestinal explants, and increased Tregs and CD103-positive regulatory dendritic cells in mesenteric lymph nodes (MLNs) were observed. Analysis of 16s-rDNA from feces of C. kefyr-treated mice demonstrated increased Lactobacillales and decreased Bacteroides compared to control flora. Transfer of intestinal microbiota also resulted in decreased Bacteroides and ameliorated symptoms of EAE. Thus, oral administration of C. kefyr ameliorated EAE by altering the microflora, accompanied by increased Tregs and CD103-positive regulatory dendritic cells in MLNs and decreased Th17 cells in the intestinal lamina propria. Interpretation Oral ingestion of C. kefyr may have beneficial effects on MS by modifying microflora. In addition, our findings also suggested the potential health benefits of dietary yeasts.

Oxidative stress and mitochondrial dysfunction are important determinants of neurodegeneration in secondary progressive multiple sclerosis (SPMS). We previously showed that febuxostat, a xanthine oxidase inhibitor, ameliorated both relapsing-remitting and secondary progressive experimental autoimmune encephalomyelitis (EAE) by preventing neurodegeneration in mice. In this study, we investigated how febuxostat protects neuron in secondary progressive EAE. A DNA microarray analysis revealed that febuxostat treatment increased the CNS expression of several mitochondria-related genes in EAE mice, most notably including GOT2, which encodes glutamate oxaloacetate transaminase 2 (GOT2). GOT2 is a mitochondrial enzyme that oxidizes glutamate to produce α-ketoglutarate for the Krebs cycle, eventually leading to the production of adenosine triphosphate (ATP). Whereas GOT2 expression was decreased in the spinal cord during the chronic progressive phase of EAE, febuxostat-treated EAE mice showed increased GOT2 expression. Moreover, febuxostat treatment of Neuro2a cells in vitro ameliorated ATP exhaustion induced by rotenone application. The ability of febuxostat to preserve ATP production in the presence of rotenone was significantly reduced by GOT2 siRNA. GOT2-mediated ATP synthesis may be a pivotal mechanism underlying the protective effect of febuxostat against neurodegeneration in EAE. Accordingly, febuxostat may also have clinical utility as a disease-modifying drug in SPMS.

A 21-year-old man was admitted to our hospital in June 2015. He felt paresthesia of toes in April 2015, which had been spreading upward, and he became difficult to walk in June. Nerve conduction study showed peripheral demyelinating neuropathy that met the diagnostic criteria for chronic inflammatory demyelinating polyneuropathy (CIDP), and the cerebrospinal fluid (CSF) examination revealed the remarkably increased protein level. In addition, magnetic resonance imaging of his brain showed a few plaques in white matter, so he was finally diagnosed with combined central and peripheral demyelination (CCPD). Moreover, anti-neurofascin155 (NF155) antibodies assayed in his serum and CSF turned out to be positive. Although he was treated with intravenous immunoglobulin and intravenous methylprednisolone, his symptoms were not ameliorated. However, plasma exchange therapy was apparently effective, and the titer of anti-NF155 antibody was reduced. Recently, the number of case reports of CIDP with CNS lesions has gradually been increasing, while the information about the diagnosis and the treatment responses are not enough. Thus, we reported our case with CCPD who was successfully treated with plasma exchange.

Objectives There has been no large-scale study of methylprednisolone pulse therapy in Asian patients with multiple sclerosis (MS) or neuromyelitis optica (NMO), despite it being widely used for acute relapse. We aimed to clarify treatment response of MS and NMO patients to methylprednisolone pulse therapy and post-pulse oral corticosteroids in real clinical practice in a multicenter study in Japan. Methods Investigators at 28 institutions collected changes in neurological symptoms/signs and Expanded Disability Status Scale (EDSS) scores before and within 1 week of completion of methylprednisolone pulse therapy carried out in 2010, and after post-pulse oral corticosteroids therapy, by retrospective review of medical records. Results In 345 patients (95.1% of all registered patients), 457 series of methylprednisolone pulse therapy were carried out for treatment of acute relapse. EDSS scores improved by 0.8 ± 1.1 (mean ± SD) after the first course. The second and third courses also produced sufficient improvements (by 0.7 and 0.6, respectively), but much smaller improvements were observed thereafter. The target neurological symptoms and signs improved in 79.5% of patients. Improvement rates were 5–20% lower after a course of pulse therapy than after a series of pulse therapy. A half dose (500 mg/day) produced less improvement than a standard dose (1000 mg/day; 65.9 vs 79.5%). During post-pulse oral corticosteroid therapy, EDSS scores decreased by 0.6 ± 0.9. No significant adverse effects were observed. Conclusions Methylprednisolone pulse therapy is beneficial in nearly 80% of Japanese MS and NMO patients, and EDSS score improvements after therapy are compatible with those in Western MS patients.

The early initiation of appropriate treatment is important for a better prognosis for patients with multiple sclerosis (MS). Although interferon (IFN-β) has been the most prescribed therapy for MS, some patients are poor responders to this therapy. Therefore, finding biomarkers to predict treatment responsiveness is required. Some patients with MS have high serum Sema4A and concurrently have characteristics of Th17-skewing conditions, and do not respond well to IFN-β therapy. In the present review, we discuss Sema4A and responsiveness to IFN-β therapy. In addition, we review biomarkers relevant to IFN-β therapy responsiveness.

A 54-year-old woman with no medical history presented with left hemiparesis and hemianopsia. Brain MRI showed an extensive lesion without enhancement in the right parietal lobe, followed by rapid cavity formation (figure 1). Brain biopsy performed 55 days after disease onset revealed decreased glial fibrillary acidic protein and aquaporin-4 (AQP4) immunoreactivity, though we could not show the activated complement due to the paucity of the sample (figure 2).

Neuromyelitis optica (NMO) is an inflammatory disorder of the central nervous system (CNS) characterized by optic neuritis and transverse myelitis. NMO is also known as Devic’s disease, after a case report by French neurologist Eugene Devic and his colleagues in the late nineteenth century. NMO has been considered a variant of multiple sclerosis (MS) and called opticospinal MS in Japan, where its prevalence is much higher than in Western countries. In 2004 however, an autoantibody, NMO-IgG (anti-aquaporin 4 antibody), was detected in the serum of patients with NMO, but not in patients with MS, indicating that NMO is independent of MS.

Neuromyelitis optica (NMO) is a recurrent neuroinflammatory disease of the optic nerves and spinal cord associated with the anti-aquaporin-4 (AQP4) antibody biomarker, NMO-IgG. As clinical and scientific research interest in NMO grows, the need for an animal model becomes more urgent. Over the past few years, several groups have developed rodent models that partially represent human NMO disease. Passive transfer of the NMO-IgG is not pathogenic alone, but in certain contexts can recruit granulocytes and lead to increased inflammation. Studies of the cellular immune response against AQP4 have also shed light on the roles of B and T cells in NMO, especially focusing on the role of Th17 T helper cells. This review discusses the contribution of the available NMO animal models to the understanding of NMO disease pathogenesis.

The blood–brain barrier and blood–nerve barrier play crucial roles in maintaining homeostasis of the central and peripheral nervous systems. Takeshita et al. reported the different molecular expression pattern in the components constituting the blood–brain barrier and blood–nerve barrier, and suggested that the blood–nerve barrier might have a distinct mechanism for T cell migration.

The nervous and immune systems have similar functional characteristics. Both have an intricate network of synaptic connections and an exquisite communication system that enable intercellular signal transduction. Although semaphorins were originally identified as guidance cues in neural development, accumulating evidence indicates that several semaphorins called ‘immune semaphorins’, such as Sema3A, 4A, 4D, 6D and 7A, are critically involved in various phases of the immune response by regulating immune cell–cell contacts or cell migration. In this review, we present recent knowledge on the functions of semaphorins and their receptors in the immune system and their potential roles in the pathogenesis of multiple sclerosis (MS), a representative CNS autoimmune disease, and its animal model, experimental autoimmune encephalomyelitis (EAE).

The immune and nervous systems have similar functional characteristics. Both have an intricate network of synaptic connections and an exquisite communication system that enable to maintain homeostasis. Although semaphorins were originally identified as guidance cues in neural development, several semaphorins such as Sema4A and 4D are involved in various phases of the immune response by regulating immune cell-cell contacts, immune cell migration and immune cell-neural cell interaction. Inappropriate expression of Sema4A, 4D, and their receptors Plexin-Bs by undetermined mechanisms causes neuroinflammation that leads to demyelination. The pathogenic role of the anti-AQP4 antibody in NMO has been speculated based on studies in vitro. The fact that passive transferred IgG collected from NMO patients who underwent therapeutic plasmapheresis exacerbated EAE indicates the pathogenicity in vivo. When the antibody once penetrates the blood-brain barrier probably under an inflammatory condition primarily causes complement-dependent astrocyte damage.

Approximately one-third of patients with multiple sclerosis (MS) exhibit markedly high-level-expression of Sema4A. The expression of Sema4A is increased on DCs in MS patients and shed from these cells in a metalloproteinase-dependent manner. DC-derived Sema4A is critical for Th17 cell differentiation, and MS patients with high Sema4A levels exhibit Th17 skewing. Furthermore, patients with high Sema4A levels have more severe disabilities and are unresponsive to IFN-β treatment. We investigated whether recombinant Sema4A abrogates the efficacy of IFN-β in mice with experimental autoimmune encephalomyelitis (EAE), an animal model of MS. Administration of Sema4A concurrently with IFN-β abrogated the efficacy of IFN-β. These effects of Sema4A were attributed to promote Th1 and Th17 differentiation and to increase adhesive activation of T cells to endothelial cells, even in the presence of IFN-β.Thus unresponsiveness to IFN-β treatment of MS patients with high Sema4A was also confirmed by model mice EAE. We recommend assaying Sema4A first, and then selecting DMD other than IFN-β for patients with high Sema4A.

Neuromyelitis optica (NMO) is an inflammatory demyelinating disease of the central nervous system (CNS). Anti-aquaporin-4 antibody (AQP4-Ab) is a highly specific serum autoantibody that is detected in patients with NMO. Several lines of evidence indicate that AQP4-Ab not only serves as a disease marker but also plays a pivotal role in the pathogenesis of NMO. Although the pathogenicity of AQP4-Ab in vivo has recently been demonstrated, the presence of CNS antigen-specific T cells is recognized as a prerequisite for the antibody to exert pathogenic effects. Thus, it remains unclear whether AQP4-Ab is the primary cause of the disease or a disease-modifying factor in NMO. Here we report that pre-treatment with complete Freund's adjuvant (CFA) alone is sufficient for AQP4-Ab to induce astrocytic damage in vivo. Our results show the primary pathogenic role of AQP4-Ab in the absence of CNS antigen-specific T cells, and suggest that danger signals provided by nonspecific inflammation can be a trigger for those who harbor the autoantibody to develop NMO.

Neuromyelitis optica (NMO) is an inflammatory demyelinating disease of the central nervous system, and humoral immunity is suggested to play an important role in the pathogenesis. The identification of an anti-aquaporin-4 antibody (AQP4-Ab, neuromyelitis optica immunoglobulin G) in the sera of patients with NMO has led to the investigation on the pathogenicity of the autoantibody. Recent immunohistological analyses revealed the primary loss of AQP4 on astrocytes and complement deposition in active lesions of NMO. In this report, we show that astrocytes are susceptible to sera from AQP4-Ab-positive patients and undergo necrosis in a complement-dependent manner. Our results suggest the primary pathogenic role of AQP4-Ab in NMO.

Reactive oxygen species (ROS) are implicated in the pathogenesis of multiple sclerosis (MS) and its murine model experimental autoimmune encephalomyelitis (EAE). The effect of edaravone, a free radical scavenger, on EAE was investigated in this study. Treatment with edaravone significantly ameliorated the clinical severity of EAE, and a reduced infiltration of lymphocytes was observed based on a histological analysis. The expression of inducible NO synthase (iNOS) in the spinal cords appeared to be reduced by the treatment with edaravone and this effect was confirmed in vitro. A reduction of both the cellular infiltration and the expression of iNOS may therefore underlie the mechanisms of the beneficial effect of edaravone on EAE.

Since interferon (IFN)-β was first approved for the treatment of relapsing-remitting multiple sclerosis (RRMS) in 1993 in the United States, the indication expanded to secondary progressive multiple sclerosis (SPMS) and clinically isolated syndrome (CIS). Supported by the evidence of efficacy derived from many clinical trials, IFN-β became an established agent. In this review, we summarize current knowledge about the putative mechanism of therapeutic effects of IFN-β and pivotal trials so far performed and discuss directions of MS therapy.

In this study, we investigated the relationship between several growth factors and inflammation development. Serum concentrations of epiregulin, amphiregulin, betacellulin, TGF-α, fibroblast growth factor 2, placental growth factor (PLGF), and tenascin C were increased in rheumatoid arthritis patients. Furthermore, local blockades of these growth factors suppressed the development of cytokine-induced arthritis in mice by inhibiting chemokine and IL-6 expressions. We found that epiregulin expression was early and followed by the induction of other growth factors at different sites of the joints. The same growth factors then regulated the expression of epiregulin at later time points of the arthritis. These growth factors were increased in patients suffering from multiple sclerosis (MS) and also played a role in the development of an MS model, experimental autoimmune encephalomyelitis. The results suggest that the temporal expression of growth factors is involved in the inflammation development seen in several diseases, including rheumatoid arthritis and MS. Therefore, various growth factor pathways might be good therapeutic targets for various inflammatory diseases.

Neurodegenerative disorders are characterized by progressive dysfunction or death and structural abnormalities of neurons. A number of diseases such as Alzheimer’s disease (AD), Parkinson’s disease (PD), and amyotrophic lateral sclerosis (ALS) that result from neurodegenerative processes are included in this category. Multiple sclerosis (MS) is an inflammatory demyelinating disease of the central nervous system (CNS). However, accumulating evidence indicates that a neurodegenerative process participates in the pathogenesis, particularly in the progressive stage of the disease. Although various causes of neurodegenerative disorders, including genetic mutations, protein abnormalities, and inflammation, have been reported, changes in neural connectivity, loss of synaptic contacts and activity, and inflammatory reactions in glial cells are common features of these disorders. It has been suggested that aberrant semaphorin expression may result in altered neuronal connectivity or synaptic function and inflammation associated with a number of degenerative neuronal disorders. This role of semaphorins has been currently suggested in the pathogenesis of AD, ALS, and MS (Table 10.1).

Semaphorins and their receptors have diverse functions in axon guidance, organogenesis, vascularization and/or angiogenesis, oncogenesis and regulation of immune responses1,2,3,4,5,6,7,8,9,10,11. The primary receptors for semaphorins are members of the plexin family2,12,13,14. In particular, plexin-A1, together with ligand-binding neuropilins, transduces repulsive axon guidance signals for soluble class III semaphorins15, whereas plexin-A1 has multiple functions in chick cardiogenesis as a receptor for the transmembrane semaphorin, Sema6D, independent of neuropilins16. Additionally, plexin-A1 has been implicated in dendritic cell function in the immune system17. However, the role of plexin-A1 in vivo, and the mechanisms underlying its pleiotropic functions, remain unclear. Here, we generated plexin-A1-deficient (plexin-A1−/−) mice and identified its important roles, not only in immune responses, but also in bone homeostasis. Furthermore, we show that plexin-A1 associates with the triggering receptor expressed on myeloid cells-2 (Trem-2), linking semaphorin-signalling to the immuno-receptor tyrosine-based activation motif (ITAM)-bearing adaptor protein, DAP12. These findings reveal an unexpected role for plexin-A1 and present a novel signalling mechanism for exerting the pleiotropic functions of semaphorins.

Biomarkers have been developed for the purpose of diagnosis, analysis of the pathogenesis, monitoring disease activity and treatment response, selection of treatment, and prediction of prognosis and risk of disease development. In accordance with the development of MRI technique, the significance of imaging biomarkers has been increasing. Whereas, there are a few established and widely-used blood/CSF biomarkers except for oligoclonal IgG bands in MS, and anti-AQP4 antibody in NMO. These biomarkers are helpful especially for the diagnosis of atypical cases. The significance of blood/CSF biomarkers are expected to increase for the prediction of the disease, selection of appropriate therapy, prediction of disease susceptibility.

GM3, the simplest ganglioside, modulates cell adhesion, proliferation and differentiation in the central nervous system and exogenously added GM3 regulates cell-cell and cell-extracellular matrix adhesion and induces apoptosis. To assess the anti-tumor action of exogenous GM3, we examined its effect on the proliferation and invasion of glioma cells. Its inhibitory effect on cell proliferation was demonstrated in vitro by 3-(4,5-dimethyl-2-thiazol-2-yl) 2,5-diphenyltetrazolium bromide (MTT) assay and in vitro in rats with meningeal gliomatosis whose survival was significantly prolonged by the intrathecal injection of GM3. Terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end-labeling (TUNEL) assay revealed that GM3 induced glioma cell apoptosis in vitro and in vitro. In rat brain slice cultures, GM3 suppressed the invasion of glioma cells; this effect manifested earlier than the inhibition of cell proliferation and before apoptosis induction. Our results suggest exogenous GM3 as a potential therapeutic agent in patients with glioma requiring adjuvant therapy.

A 66-year-old man developed progressive painful dysesthesia in his hands and feet over 3 months. His vibration sense was impaired and sensory nerve action potentials of the limbs were not evoked. Biopsy of the peroneal nerve revealed sensory neuropathy. Positive anti-Hu antibody facilitated delineation of a right hilar mass and a metastatic lymph node in thoracic CT scan. He was diagnosed as small cell lung cancer associated with paraneoplastic sensory neuropathy. A complete response was achieved through chemotherapy (carboplatin and etoposide) and subsequent radiation therapy. Notably, his neurological conditions, although not changed during the hospitalization, gradually improved afterwards.

The proliferation of type-1 astrocytes is strongly inhibited by homotypic cell-contact. To examine the mechanisms mediating this inhibition of proliferation, the expression of cell cycle related proteins was compared between exponential growth-phase and contact-inhibited astrocytes. Expression of the cyclin-dependent kinase (Cdk) inhibitor p27Kip1 was upregulated 10-fold in confluent compared with growth-phase cultures. Density-induced expression of p27Kip1 was reversible. When confluent cultures of astrocytes expressing high levels of p27Kip1 were replated at low density, the expression of p27Kip1 decreased rapidly. In contrast to p27Kip1, the expression levels of the cell cycle protein, cyclin A was decreased ten-fold in confluent cultures compared with those in growth phase. In addition, the ratio of hyperphosphorylated to hypophosphorylated retinoblastoma protein (pRb) decreased concomitantly with the increase of p27Kip1 and the decrease of cyclin A levels. These results suggest that increased expression of p27Kip1 and decreased expression of cyclin A underlie the reduction in proliferation of contact inhibited astrocytes. High levels of mitogenic stimulation could transiently override contact-dependent inhibition of astrocyte proliferation. Addition of exogenous epidermal growth factor (EGF) resulted in elevated proliferation at high density and formation of multiple cell layers. Addition of EGF did not substantially alter levels of p27Kip1 or cyclin A, but did elevate the levels of cyclin D1. Such changes in cell cycle protein expression may contribute to elevated cell proliferation seen in reactive gliosis after injury to the adult CNS. J. Neurosci. Res. 66:487–496, 2001. © 2001 Wiley-Liss, Inc.

The normal adult vertebrate nervous system is a relative quiescent tissue in terms of cell proliferation. However, astrocytes in many regions of the central nervous system (CNS) retain the capacity to undergo cell division. To examine the mechanisms that regulate the proliferation of astrocytes in the CNS we have utilized an in vitro assay in which astrocyte density and cellular environment could be regulated. We demonstrate that type 1 astrocytes derived from the cerebral cortex of developing rats exhibit a profound density-dependent inhibition of proliferation. This inhibition of proliferation was cell type specific, but not restricted to type 1 astrocytes. NIH 3T3 cells but not smooth muscle cells inhibited astrocyte proliferation, while contact-inhibited astrocytes did not inhibit oligodendrocyte proliferation. Co-culture of type 1 astrocytes with neurons from a variety of sources resulted in induction of a process-bearing astrocyte morphology and promoted glial cell proliferation. Thus, induction of a process-bearing astrocyte morphology does not lead to a cessation of proliferation. The inhibition of astrocyte proliferation did not appear to be mediated through the release or sequestration of soluble factors but rather could be induced by membrane-associated factors.

Demyelinating lesions have been observed in severe combined immunodeficient (SCID) mice after intracisternal administration of cerebrospinal fluid cells (CSFC) from patients with multiple sclerosis (MS). Further investigation in our laboratory revealed that CSFC from 6 to 15 patients at exacerbation of MS caused demyelination. The factor leading to demyelination appears to be the high frequency of relapses during a short period, but not to the severity of the disease. Neuropathological and immunohistochemical studies revealed that a lack of inflammatory mononuclear cell infiltration within and around the demyelinating lesions or in leptomeninges was a common characteristic in all SCID mice with CSFC-induced demyelination. In affected mice killed 2-3 weeks after intracisternal administration of CSFC, foamy/vacuolar lesions with a small or moderate number of lipid-laden macrophages were seen in the white matter. Ultrastructurally, relative preservation of axons, in contrast to myelinoclastic features, as well as some remyelinated axons were observed. In affected SCID mice killed 4-6 weeks after intracisternal administration, more widespread foamy macrophages and necrotic foci with poor remyelination were seen. The findings were similar to those seen in experimental allergic encephalomyelitis, though without lymphocytic infiltration, but were quite different from the lesions observed in Theiler's murine encephalitis virus infection. The absence of an immunohistochemical reaction to the human leukocyte common antigen in the infiltrating mononuclear cells suggested that the graft-versus-host reaction was unlikely cause of the demyelinating lesions.

Magnetic resonance imaging (MRI) is widely employed for the diagnosis of multiple sclerosis (MS). However, sometimes, the lesions found by MRI do not correlate with the neurological impairments observed in MS patients. We recently showed autoreactive T cells accumulate in the fifth lumbar cord (L5) to pass the blood–brain barrier and cause inflammation in the central nervous system of experimental autoimmune encephalomyelitis (EAE) mice, an MS model. We here investigated this early event using ultrahigh-field MRI. T2-weighted image signals, which conform to the water content, increased in L4 and L5 during the development of EAE. At the same time, the sizes of L4 and L5 changed. Moreover, angiographic images of MRI showed branch positions of the blood vessels in the lower lumbar cords were significantly altered. Interestingly, EAE mice showed occluded and thickened vessels, particularly during the peak phase, followed by reperfusion in the remission phase. Additionally, demyelination regions of some MS patients had increased lactic acid content, suggesting the presence of ischemic events. These results suggest that inflammation-mediated alterations in the lower lumbar cord change the homeostasis of the spinal cord and demonstrate that ultrahigh-field MRI enables the detection of previously invisible pathological alterations in EAE.

Approximately one-third of patients with multiple sclerosis (MS) respond poorly to interferon-beta (IFN-β) therapy. Serum Sema4A is increased in MS patients, and those who have high Sema4A do not respond to IFN-β therapy. In this study, we investigated whether recombinant Sema4A abrogates the efficacy of IFN-β in mice with experimental autoimmune encephalomyelitis (EAE), an animal model of MS. Administration of Sema4A concurrently with IFN-β diminished the efficacy of IFN-β in EAE. These effects of Sema4A were attributed to promote Th1 and Th17 differentiation and to increase adhesive activation of T cells to endothelial cells, even in the presence of IFN-β.

Various neuroprotective factors have been shown to help prevention of neuronal cell death, which is responsible for the progression of neurodegenerative diseases such as amyotrophic lateral sclerosis (ALS). However, most of these therapeutic potentials have been tested by administration of recombinant proteins, transgenic expression or virus vector-mediated gene transfer. Therefore, it remains to be clarified whether any endogenous factors has advantage for neuroprotection in a pathological nervous system. Here we show the role of BAFF-R signaling pathway in the control of neural cell survival. Both B cell–activating factor (BAFF) and its receptor (BAFF-R) are expressed in mouse neurons and BAFF-R deficiency reduces the survival of primary cultured neurons. Although many studies have so far addressed the functional role of BAFF-R on the differentiation of B cells, impaired BAFF-R signaling resulted in accelerated disease progression in an animal model of inherited ALS. We further demonstrate that BAFF-R deficient bone marrow cells or genetic depletion of B cells does not affect the disease progression, indicating that BAFF-mediated signals on neurons, not on B cells, support neural cell survival. These findings suggest opportunities to improve therapeutic outcome for patients with neurodegenerative diseases by synthesized BAFF treatment.

Objectives Oxidative stress plays an important role in the pathogenesis of multiple sclerosis (MS). Though reactive oxygen species (ROS) are produced by various mechanisms, xanthine oxidase (XO) is a major enzyme generating ROS in the context of inflammation. The objectives of this study were to investigate the involvement of XO in the pathogenesis of MS and to develop a potent new therapy for MS based on the inhibition of ROS. Methods XO were assessed in a model of MS: experimental autoimmune encephalomyelitis (EAE). The contribution of XO-generated ROS to the pathogenesis of EAE was assessed by treating EAE mice with a novel XO inhibitor, febuxostat. The efficacy of febuxostat was also examined in in vitro studies. Results We showed for the first time that the expression and the activity of XO were increased dramatically within the central nervous system of EAE mice as compared to naive mice. Furthermore, prophylactic administration of febuxostat, a XO inhibitor, markedly reduced the clinical signs of EAE. Both in vivo and in vitro studies showed infiltrating macrophages and microglia as the major sources of excess XO production, and febuxostat significantly suppressed ROS generation from these cells. Inflammatory cellular infiltration and glial activation in the spinal cord of EAE mice were inhibited by the treatment with febuxostat. Importantly, therapeutic efficacy was observed not only in mice with relapsing-remitting EAE but also in mice with secondary progressive EAE by preventing axonal loss and demyelination. Conclusion These results highlight the implication of XO in EAE pathogenesis and suggest XO as a target for MS treatment and febuxostat as a promising therapeutic option for MS neuropathology.

A cytokine-mediated excessive increase in nitric oxide (NO) by macrophages or glial cells via an inducible isoform of NO synthase (iNOS) has been proposed to play an important role in demyelinating diseases. To further investigate the role of iNOS in demyelination, experimental allergic encephalomyelitis (EAE), a known animal model of multiple sclerosis (MS) in mice, was chosen in this study. A semiquantitative reverse transcriptase-polymerase chain reaction (RT/PCR) analysis revealed an increase in the mRNA levels of iNOS and cytokines known to induce iNOS or inflammatory cytokines (interleukin (IL)-1 alpha, IL-1 beta, IL-2, IL-6, interferon (IFN)-gamma, tumor necrosis factor (TNF)-alpha and TNF-beta) in the spinal cord corresponding to the severity of the disease without significant change in the mRNA levels of immunoregulatory cytokines (IL-4, IL-10 and transforming growth factor (TGF)-beta) during the course of EAE. An immunohistochemical examination of the spinal cord using an iNOS-specific antibody showed iNOS-positive cells to be mainly inflammatory cells with a higher frequency of iNOS-positive cells at the peak of EAE than in the early phase. These iNOS-positive cells at the peak appeared to be composed of infiltrating macrophages and most of them were located in the necrotic area. These results suggested that cytokine-induced excessive NO via iNOS by macrophages caused tissue damage in the central nervous system in EAE.

Multiple sclerosis (MS) is a demyelinating autoimmune disease of the CNS and a leading cause of lasting neurologic disabilities in young adults. Although the precise mechanism remains incompletely understood, Ag presentation and subsequent myelin-reactive CD4+ T cell activation/differentiation are essential for the pathogenesis of MS. Although semaphorins were initially identified as axon guidance cues during neural development, several semaphorins are crucially involved in various phases of immune responses. Sema4A is one of the membrane-type class IV semaphorins, which we originally identified from the cDNA library of dendritic cell (DC). Sema4A plays critical roles in T cell activation and Th1 differentiation during the course of experimental autoimmune encephalomyelitis, an animal model of MS; however, its pathological involvement in human MS has not been determined. In this study, we report that Sema4A is increased in the sera of patients with MS. The expression of Sema4A is increased on DCs in MS patients and shed from these cells in a metalloproteinase-dependent manner. DC-derived Sema4A is not only critical for Th1 but also for Th17 cell differentiation, and MS patients with high Sema4A levels exhibit Th17 skewing. Furthermore, patients with high Sema4A levels have more severe disabilities and are unresponsive to IFN-β treatment. Taken together, our results suggest that Sema4A is involved in the pathogenesis of MS by promoting Th17 skewing.

Recent advances in the field of neuromyelitis optica (NMO) research provided convincing evidence that anti-AQP4 antibody (AQP4-Ab) not only serves as a highly specific disease marker, but also plays an essential role in the pathogenesis of the disease. Although it is now widely recognized that AQP4-Ab induces astrocytic necrosis in a complement-dependent manner, additional triggers are also suspected as a prerequisite for the development of the disease. Unraveling these unresolved aspects of the disease will provide substantial insight into still controversial issues in the pathogenesis of NMO.

The human peripheral myelin protein 22 (PMP-22) gene has been mapped to chromosome 17p11.2 in the duplicated region associated with Charcot-Marie-Tooth disease type 1A. Southern blot analysis using PMP-22 as a probe indicated that the PMP-22 gene was duplicated in 5 patients from unrelated Japanese families with Charcot-Marie-Tooth disease type 1. In order to investigate whether or not an extra copy of PMP-22 has an effect on its gene expression, we analyzed relative expression of messenger RNA for PMP-22 and protein 0 (P0) against beta-actin by Northern blotting in biopsied nerves of the patients with type 1A disease, and compared the results with those of patients having other demyelinating neuropathies and the autopsied nerves of patients without neuropathies. The relative expression of PMP-22 messenger RNA in 5 patients with Charcot-Marie-Tooth disease type 1A was significantly higher than that in 5 patients with other demyelinating neuropathies (p < 0.05). There was no statistically significant difference in P0 expression between them. This study provided direct evidence for elevated expression of PMP-22 in peripheral nerves of patients with Charcot-Marie-Tooth disease type 1A as the result of a gene dosage effect. However, the relation between elevated expression of PMP-22 and the mechanism causing demyelination remains undetermined.

Although several major histocompatibility complex (MHC)-wide single-nucleotide polymorphism (SNP) studies have been performed in populations of European descent, none have been performed in Asian populations. The objective of this study was to identify human leukocyte antigen (HLA) loci associated with multiple sclerosis (MS) in a Japanese population genotyped for 3534 MHC region SNPs. Using a logistic regression model, two SNPs (MHC Class III SNP rs422951 in the NOTCH4 gene and MHC Class II SNP rs3997849, susceptible alleles A and G, respectively) were independently associated with MS susceptibility (204 patients; 280 controls), two (MHC Class II SNP rs660895 and MHC Class I SNP rs2269704 in the NRM gene, susceptible alleles G and G, respectively) with aquaporin-4− (AQP4−) MS susceptibility (149 patients; 280 controls) and a single SNP (MHC Class II SNP rs1694112, susceptible allele G) was significant when contrasting AQP4 + against AQP4− patients. Haplotype analysis revealed a large susceptible association, likely DRB1*04 or a locus included in the DRB1*04 haplotype, with AQP4− MS, which excluded DRB1*15:01. This study is the largest study of the HLA’s contribution to MS in Japanese individuals.

BACKGROUND: Certain intestinal microflora are thought to regulate the systemic immune response. Lactic acid bacteria are one of the most studied bacteria in terms of their beneficial effects on health and autoimmune diseases; one of which is Multiple sclerosis (MS) which affects the central nervous system. We investigated whether the lactic acid bacterium Pediococcus acidilactici, which comprises human commensal bacteria, has beneficial effects on experimental autoimmune encephalomyelitis (EAE), an animal model of MS. METHODOLOGY/PRINCIPAL FINDINGS: P. acidilactici R037 was orally administered to EAE mice to investigate the effects of R037. R037 treatment suppressed clinical EAE severity as prophylaxis and therapy. The antigen-specific production of inflammatory cytokines was inhibited in R037-treated mice. A significant increase in the number of CD4(+) Interleukin (IL)-10-producing cells was observed in the mesenteric lymph nodes (MLNs) and spleens isolated from R037-treated naive mice, while no increase was observed in the number of these cells in the lamina propria. Because only a slight increase in the CD4(+)Foxp3(+) cells was observed in MLNs, R037 may primarily induce Foxp3(-) IL10-producing T regulatory type 1 (Tr1) cells in MLNs, which contribute to the beneficial effect of R037 on EAE. CONCLUSIONS/SIGNIFICANCE: An orally administered single strain of P. acidilactici R037 ameliorates EAE by inducing IL10-producing Tr1 cells. Our findings indicate the therapeutic potential of the oral administration of R037 for treating multiple sclerosis.

A large proportion of patients with multiple sclerosis (MS) show cognitive impairment. Multiple sclerosis tends to affect people in their productive years. Niino et al. reported the associations of cognitive impairment with magnetic resonance imaging findings and social activities in Japanese patients with multiple sclerosis.