Regulation of proteins mediating neurodegeneration in experimental autoimmune encephalomyelitis and multiple sclerosis

Multiple sclerosis is characterized by inflammatory demyelination and axonal loss as pathophysiological correlates of relapsing activity and progressive development of clinical disability. The molecular processes involved in this pathogenesis are still unclear as they are quite complex and heterogeneous. In this article we present protein expression analysis of brain and spinal cord tissues from different models of murine experimental autoimmune encephalomyelitis (EAE), the most commonly used animal model for multiple sclerosis. We observed a number of EAE-specific protein expression and PTM differences. Proteome analysis was extended to multiple sclerosis specimens in order to validate the EAE findings. Our findings suggest the regulation of a number of proteins that shed light on the molecular mechanisms of the disease processes taking place in EAE and multiple sclerosis. We found consistent modulation of proteins including serum amyloid P component, sirtuin 2, dihydropyrimidinase-related protein family proteins, stathmin 1, creatine kinase B and chloride intracellular channel protein 1. Functional classification of the proteins by database and the literature mining reveals their association with neuronal development and myelinogenesis, suggesting possible disease processes that mediate neurodegeneration.     

腺苷A2AR拮抗剂对中枢炎症性小胶质细胞形态和功能的影响

目的:探讨腺苷A2A受体拮抗剂对实验性自身免疫性脑脊髓炎（EAE）的治疗作用及其对中枢炎症性小胶质细胞形态和功能的影响。方法:MOG35-55免疫诱导建立EAE模型,EAE小鼠出现神经功能缺损症状后开始腹腔注射腺苷A2AR拮抗剂至发病后第10天。ELISA法检测中枢神经系统内IFN-γ、IL-17、TGF-β、IL-10的表达情况,免疫荧光双重染色法检测小胶质细胞内M1型细胞标志物诱导型一氧化氮合酶（iNOS）和M2型细胞标志物精氨酸酶I（ArgI）的合成情况。离体培养BV-2小胶质细胞,LPS诱导的小胶质细胞炎症反应,并予A2AR拮抗剂干预,Real-time PCR和ELISA法检测M1型和M2型细胞相关的细胞因子RNA表达水平和分泌水平。Western Blot法检测各组小胶质细胞内M1型和M2型细胞标志物的表达量。结果:腺苷A2AR拮抗剂能有效缓解发病后EAE小鼠的神经功能缺损症状,降低IFN-γ的分泌水平,使M1型细胞相关的iNOS合成减少,M2型细胞相关的ArgI合成增多。腺苷A2AR拮抗剂能减少LPS刺激后BV-2小胶质细胞M1型细胞相关的细胞因子IL-1β的mRNA表达量和分泌量,对M2型细胞相关的细胞因子及蛋白无显著影响。结论:腺苷A2AR拮抗剂对发病后的EAE小鼠有肯定的治疗作用,其机制可能与改变中枢炎症过程中小胶质细胞的表型（M1/M2转换）改变（形态和功能）有关。     

Dendritic Cells and Multiple Sclerosis: Disease,Tolerance and Therapy

Multiple sclerosis (MS) is a devastating neurological disease that predominantly affects young adults resulting in severe personal and economic impact. The majority of therapies for this disease were developed in, or are beneficial in experimental autoimmune encephalomyelitis (EAE), the animal model of MS. While known to target adaptive anti-CNS immune responses, they also target, the innate immune arm. This mini-review focuses on the role of dendritic cells (DCs), the professional antigen presenting cells of the innate immune system. The evidence for a role for DCs in the appropriate regulation of anti-CNS autoimmune responses and their role in MS disease susceptibility and possible therapeutic utility are discussed. Additionally, the current controversy regarding the evidence for the presence of functional DCs in the normal CNS is reviewed. Furthermore, the role of CNS DCs and potential routes of their intercourse between the CNS and cervical lymph nodes are considered. Finally, the future role that this nexus between the CNS and the cervical lymph nodes might play in site directed molecular and cellular therapy for MS is outlined.     

Pertussis Toxin Inhibits Encephalitogenic T-Cell Infiltration and Promotes a B-Cell-Driven Disease during Th17-EAE

Pertussis toxin (PTX) is a required co-adjuvant for experimental autoimmune encephalomyelitis (EAE) induced by immunization with myelin antigen. However, PTX’s effects on EAE induced by the transfer of myelin-specific T helper cells is not known. Therefore, we investigated how PTX affects the Th17 transfer EAE model (Th17-EAE). We found that PTX significantly reduced Th17-EAE by inhibiting chemokine-receptor-dependent trafficking of Th17 cells. Strikingly, PTX also promoted the accumulation of B cells in the CNS, suggesting that PTX alters the disease toward a B-cell-dependent pathology. To determine the role of B cells, we compared the effects of PTX on Th17-EAE in wild-type (WT) and B-cell-deficient (µMT) mice. Without PTX treatment, disease severity was equivalent between WT and µMT mice. In contrast, with PTX treatment, the µMT mice had significantly less disease and a reduction in pathogenic Th17 cells in the CNS compared to the WT mice. In conclusion, this study shows that PTX inhibits the migration of pathogenic Th17 cells, while promoting the accumulation of pathogenic B cells in the CNS during Th17-EAE. These data provide useful methodological information for adoptive-transfer Th17-EAE and, furthermore, describe another important experimental system to study the pathogenic mechanisms of B cells in multiple sclerosis.     

Neuroprotective Effect of Glatiramer Acetate on Neurofilament Light Chain Leakage and Glutamate Excess in an Animal Model of Multiple Sclerosis

Axonal and neuronal pathologies are a central constituent of multiple sclerosis (MS) and its animal model, experimental autoimmune encephalomyelitis (EAE), induced by the myelin oligodendrocyte glycoprotein (MOG) 35–55 peptide. In this study, we investigated neurodegenerative manifestations in chronic MOG 35–55 induced EAE and the effect of glatiramer acetate (GA) treatment on these manifestations. We report that the neuronal loss seen in this model is not attributed to apoptotic neuronal cell death. In EAE-affected mice, axonal damage prevails from the early disease phase, as revealed by analysis of neurofilament light (NFL) leakage into the sera along the disease duration, as well as by immunohistological examination. Elevation of interstitial glutamate concentrations measured in the cerebrospinal fluid (CSF) implies that glutamate excess plays a role in the damage processes inflicted by this disease. GA applied as a therapeutic regimen to mice with apparent clinical symptoms significantly reduces the pathological manifestations, namely apoptotic cell death, NFL leakage, histological tissue damage, and glutamate excess, thus corroborating the neuroprotective consequences of this treatment.     

咪唑克生对实验性变态反应性脑脊髓炎小鼠血脑屏障紧密连接的影响

目的: 观察咪唑克生(idazoxan,IDA)对实验性变态反应性脑脊髓炎(experimental autoimmune encephalomyelitis, EAE)小鼠的血脑屏障(blood-brain barrier, BBB)紧密连接的影响。方法: 选用36只8周的C57BL/6小鼠,随机分为空白对照组、EAE组和IDA干预组各12只,采用MOG_35-55诱导经典EAE模型,干预组采用IDA 2 mg/kg 腹腔注射、每天两次、共15 d。观察每组大鼠发病情况并进行神经功能缺损评分,采用HE染色和LFB髓鞘染色方法观察病理改变,采用伊文思蓝荧光定量方法检测BBB通透性的变化,透射电镜观察BBB紧密连接超微结构,并用Western blot检测BBB紧密连接蛋白ZO-1、Occludin、Claudin-5、JAM-1的表达。结果: 空白对照组动物无一发病,与EAE组比较, IDA干预组神经功能缺损评分明显下降,炎性病灶和脱髓鞘病灶明显减少,BBB通透性明显降低,BBB超微结构的破坏明显减轻,BBB紧密连接相关蛋白ZO-1、Claudin-5的表达明显升高,差异具有统计学意义(P<0.05)。结论: IDA可能通过上调血脑屏障紧密连接蛋白ZO-1和Claudin-5的表达从而减轻EAE时的血脑屏障破坏而发挥对EAE小鼠的神经保护作用。     

CARD9 Deficiency Increases Hippocampal Injury Following Acute Neurotropic Picornavirus Infection but Does Not Affect Pathogen Elimination

Neurotropic viruses target the brain and contribute to neurologic diseases. Caspase recruitment domain containing family member 9 (CARD9) controls protective immunity in a variety of infectious disorders. To investigate the effect of CARD9 in neurotropic virus infection, CARD9^−/− and corresponding C57BL/6 wild-type control mice were infected with Theiler’s murine encephalomyelitis virus (TMEV). Brain tissue was analyzed by histology, immunohistochemistry and molecular analyses, and spleens by flow cytometry. To determine the impact of CARD9 deficiency on T cell responses in vitro, antigen presentation assays were utilized. Genetic ablation of CARD9 enhanced early pro-inflammatory cytokine responses and accelerated infiltration of T and B cells in the brain, together with a transient increase in TMEV-infected cells in the hippocampus. CARD9^−/− mice showed an increased loss of neuronal nuclear protein⁺ mature neurons and doublecortin⁺ neuronal precursor cells and an increase in β-amyloid precursor protein⁺ damaged axons in the hippocampus. No effect of CARD9 deficiency was found on the initiation of CD8⁺ T cell responses by flow cytometry and co-culture experiments using virus-exposed dendritic cells or microglia-enriched glial cell mixtures, respectively. The present study indicates that CARD9 is dispensable for the initiation of early antiviral responses and TMEV elimination but may contribute to the modulation of neuroinflammation, thereby reducing hippocampal injury following neurotropic virus infection.     

骨化三醇对实验性自身免疫性脑脊髓炎的治疗作用及相关机制

目的探讨骨化三醇(Calcitriol)对实验性自身免疫性脑脊髓炎(Experimental autoimmune encephalomyelitis,EAE)的治疗作用及相关机制。方法用含200μg髓鞘少突胶质细胞糖蛋白35-55肽段(Myelin oligodendrocyte glycoprotein 33-35,MOG33-35)、250μg结核菌素的50μl弗氏不完全佐剂(IFA)皮内免疫C57BL/6小鼠,并分别于免疫当天和第2天注射百日咳毒素,建立EAE实验性动物模型(EAE组);骨化三醇组从免疫当天起隔日腹腔注射骨化三醇100 ng进行治疗,观察两组小鼠临床评分的差异;于EAE发病高峰期处死小鼠,取脊髓及淋巴结,通过HE及LFB染色观察脊髓中炎细胞浸润及髓鞘脱失;采用流式细胞术检测两组淋巴细胞CD4+T细胞亚型的分布。结果与EAE组比较,骨化三醇组发病延缓且发病较轻,临床评分差异有统计学意义(P<0.05或P<0.01或P<0.001);骨化三醇组较EAE组小鼠脊髓白质炎性细胞浸润明显减少,脱髓鞘斑块明显减轻;骨化三醇组与EAE组相比,Th17细胞亚群明显受到抑制(P<0.05),而Th2和Treg细胞水平明显升高(P均<0.05)。结论骨化三醇可以延缓EAE发病,减轻临床症状及病理改变,并能够通过调节CD4+T细胞亚群平衡,即抑制Th17细胞,上调Th2和Treg细胞水平发挥对EAE的预防和治疗作用。     

胍丁胺对实验性变态反应性脑脊髓炎中枢神经系统内细胞因子IFN-γ、IL-10的影响

目的: 观察胍丁胺对实验性变态反应性脑脊髓炎(EAE) 中枢神经系统(CNS) 内细胞因子IFN-γ和IL-10 的影响。方法: 用豚鼠全脊髓匀浆免疫Wistar 大鼠建立EAE 动物模型, 应用双抗体夹心ELISA 法观察不同剂量胍丁胺(分别为25 、50 、100 mg /kg) 对EAE 大鼠脑和脊髓组织内细胞因子IFN-γ和IL-10 水平的影响。结果: 胍丁胺可降低Wistar 大鼠EAE 的发病率, 减轻其临床症状。与空白对照组比较, 模型组大鼠脑和脊髓组织中的IFN-γ水平增加和IL-10 水平降低(P <0.05 或P <0.01), 而胍丁胺干预的3 组大鼠CNS内脑和脊髓组织中的IFN-γ水平降低和IL-10 水平增加。结论: 胍丁胺能调节EAE 中的Th1 /Th2比例平衡, 降低IFN-γ水平, 升高IL-10 水平。     

B细胞在MOG_(35-55)诱导的小鼠实验性自身免疫性脑脊髓炎中的作用

目的探讨B细胞参与MOG35-55诱导的实验性自身免疫性脑脊髓炎(Experimental autoimmune encelphalomyelitis,EAE)小鼠模型的可能机制。方法采用MOG35-55肽段免疫C57BL/6小鼠建立EAE模型;采用临床评分检测EAE模型建立情况,HE和快蓝染色观察脊髓炎性细胞浸润和脱髓鞘状况,流式细胞术检测B细胞活化程度,免疫组化法检测脾组织生发中心的形成,ELISA法检测IgG1、IgG2a和IgG2b的分泌水平。结果成功建立了MOG35-55诱导的EAE小鼠模型,EAE组临床评分明显高于弗氏完全佐剂(Complete Freund adjuvant,CFA)组(P<0.001),EAE组小鼠脊髓可见明显的炎性细胞浸润和脱髓鞘斑块;在EAE组发病起始期(免疫后第5天和第8天),外周免疫器官活化B细胞表达水平明显高于CFA组(P<0.01);在发病高峰期(免疫后第15天)EAE组小鼠脾中形成生发中心,而CFA组未见生发中心形成,且外周血抗MOG35-55抗体分泌水平明显高于CFA组(P<0.005)。结论 MOG35-33肽段可以诱导B细胞活化,进而可能通过发挥体液免疫作用介导EAE疾病的发生。