In acute experimental autoimmune encephalomyelitis,infiltrating macrophages are immune activated,whereas microglia remain immune suppressed

Multiple sclerosis (MS) is an autoimmune demyelinating disorder of the central nervous system (CNS) characterized by loss of myelin accompanied by infiltration of T‐lymphocytes and monocytes. Although it has been shown that these infiltrates are important for the progression of MS, the role of microglia, the resident macrophages of the CNS, remains ambiguous. Therefore, we have compared the phenotypes of microglia and macrophages in a mouse model for MS, experimental autoimmune encephalomyelitis (EAE). In order to properly discriminate between these two cell types, microglia were defined as CD11b^pos CD45^int Ly‐6C^neg, and infiltrated macrophages as CD11b^pos CD45^high Ly‐6C^pos. During clinical EAE, microglia displayed a weakly immune‐activated phenotype, based on the expression of MHCII, co‐stimulatory molecules (CD80, CD86, and CD40) and proinflammatory genes [interleukin‐1β (IL‐1β) and tumour necrosis factor‐ α (TNF‐α)]. In contrast, CD11b^pos CD45^high Ly‐6C^pos infiltrated macrophages were strongly activated and could be divided into two populations Ly‐6C^int and Ly‐6C^high, respectively. Ly‐6C^high macrophages contained less myelin than Ly‐6C^int macrophages and expression levels of the proinflammatory cytokines IL‐1β and TNF‐α were higher in Ly‐6C^int macrophages. Together, our data show that during clinical EAE, microglia are only weakly activated whereas infiltrated macrophages are highly immune reactive. GLIA 2014;62:1724–1735     

Mesenchymal stem cells effectively modulate pathogenic immune response in experimental autoimmune encephalomyelitis

OBJECTIVE: To evaluate the ability of mesenchymal stem cells (MSCs), a subset of adult stem cells from bone marrow, to cure experimental autoimmune encephalomyelitis. METHODS: The outcome of the injection of MSCs, in mice immunized with the peptide 139-151 of the proteolipid protein (PLP), was studied analyzing clinical and histological scores of treated mice. The fate of MSCs labeled with the green fluorescent protein was tracked in vivo by a photon emission imaging system and postmortem by immunofluorescence. The modulation of the immune response against PLP was studied through the analysis of in vivo T- and B-cell responses and by the adoptive transfer of MSC-treated encephalitogenic cells. RESULTS: MSC-treated mice showed a significantly milder disease and fewer relapses compared with control mice, with decreased number of inflammatory infiltrates, reduced demyelination, and axonal loss. In contrast, no evidence of green fluorescent protein-labeled neural cells was detected inside the brain parenchyma, thus not supporting the hypothesis of MSCs transdifferentiation. In vivo, PLP-specific T-cell response and antibody titers were significantly lower in MSC-treated mice. When adoptively transferred, encephalitogenic T cells activated against PLP(139-151) in the presence of MSCs induced a milder disease compared with that induced by untreated encephalitogenic T cells. These cells showed decreased production of interferon-gamma and tumor necrosis factor-alpha and did not proliferate on antigen recall, and thus were considered anergic. INTERPRETATION: Overall, these findings suggest that the beneficial effect of MSCs in experimental autoimmune encephalomyelitis is mainly the result of an interference with the pathogenic autoimmune response.     

FTY720 ameliorates MOG‐induced experimental autoimmune encephalomyelitis by suppressing both cellular and humoral immune responses

FTY720, an oral sphingosine 1‐phosphate (S1P) receptor modulator, has shown efficacy in phase II trials in patients with relapsing‐remitting multiple sclerosis (MS). Although this molecule is thought to immunosuppress by inhibiting lymphocyte egress from the lymph nodes, the full spectrum of FTY720's actions has not yet been uncovered. In this study, we investigated the effects of FTY720 treatment on disease severity and histopathology of MOG‐induced experimental autoimmune encephalomyelitis (EAE) in the dark agouti (DA) rat, a model that closely mimics several features of MS. The effects of FTY720 on T‐cell subsets, anti‐MOG antibody production, and mRNA expression of a number of cytokines and other genes were also examined. Commencement of treatment before disease onset prevented the appearance of clinical disease. Therapeutic treatment after established disease reduced clinical scores and substantially attenuated inflammation, demyelination, and axon loss. EAE suppression was associated with a reduction in all measured T‐cell subsets in blood and spleen and a significant decrease in serum IgG_2a levels. However, in the lymph nodes, all T‐cell subsets except for naïve T cells and recent thymic emigrants remained unaffected. In addition, FTY720 treatment led to a significant inhibition in interferon‐γ, inducible nitric oxide synthase, and glial cell line‐derived neurotrophic factor mRNA expression in the MOG‐EAE spinal cord. In conclusion, our findings indicate that FTY720‐mediated S1P receptor modulation ameliorates chronic relapsing MOG‐EAE by suppressing both cellular and humoral immune responses. © 2009 Wiley‐Liss, Inc.     

Phenytoin at optimum doses ameliorates experimental autoimmune encephalomyelitis via modulation of immunoregulatory cells

We investigated the optimum doses of phenytoin for treatment of myelin oligodendrocyte glycoprotein-induced experimental autoimmune encephalomyelitis (EAE). Oral and intraperitoneal administrations of 0.25 to 1.0mg per mouse (12.5-50mg/kg) 3 times a week improved the clinical course. Intraperitoneal injections of 1.0mg phenytoin were the most effective, as a significant reduction in EAE severity was seen after only 2 administrations with that protocol. Treatment efficacy was associated with amelioration of cellular infiltrates in the CNS, and an increase in CD4(+)Foxp3(+) and CD4(+)CD25(+)CD127(-) regulatory T cells as well as CD8(+) suppressor/cytotoxic T cells in blood.     

Behavioral aspects of experimental autoimmune encephalomyelitis

Acute inflammation is known to induce a depressive-like sickness behavior syndrome in humans and in experimental animals. In the present study, we sought to determine whether a chronic neuroautoimmune inflammation is also associated with a similar behavioral syndrome. Experimental autoimmune encephalomyelitis (EAE) was induced in SJL/J female mice by adoptive transfer of lymph node cells, and sickness behavior symptoms, including anorexia, loss of body weight, reduced social exploration, and decreased preference for sucrose solution were measured. We report that these components of sickness behavior were induced during the acute phase of the disease, and recovered in later phases. Moreover, the onset and recovery of the behavioral symptoms preceded the onset and recovery of the neurological signs, respectively. Since EAE is considered a model for multiple sclerosis (MS), it is suggested that EAF-induced behavioral changes may serve as a model for the depressive symptomatology that characterizes most MS patients.     

Adrenergic modulation of survival and cellular immune functions during polymicrobial sepsis

OBJECTIVE: An immunomodulatory effect of epinephrine has been reported that is supposed to be mediated via beta-adrenergic receptors. The effect of epinephrine and/or beta-adrenergic blockade on cellular immune functions during systemic inflammation has not yet been investigated. METHODS: Male NMRI mice were treated with either an infusion of epinephrine (0.05 mg/kg/h i.p.), administration of the nonselective beta-adrenoceptor antagonist propranolol (0.5 mg/kg s.c.), or a combination of epinephrine and propranolol after induction of a polymicrobial sepsis by cecal ligation and puncture. Forty-eight hours thereafter survival and cellular immune functions (splenocyte proliferation, splenocyte apoptosis and cytokine release, distribution of leukocyte subsets) were determined. RESULTS: Infusion of epinephrine did not affect lethality of septic mice but induced alterations of splenocyte apoptosis, splenocyte proliferation and IL-2 release and was associated with profound changes of circulating immune cell subpopulations. Treatment with propranolol augmented the epinephrine-induced increase of splenocyte apoptosis, did not affect the decrease of splenocyte proliferation and IL-2 release, augmented the release of IL-6 and antagonized the mobilization of natural killer cells observed in epinephrine-treated animals. Furthermore, these immunologic alterations were accompanied by a significant increase of sepsis-induced mortality. Coadministration of propranolol and epinephrine augmented the propranolol-induced changes of splenocyte apoptosis and IL-6 release and was associated with the highest mortality of septic mice. CONCLUSION: Epinephrine infusion modulated cellular immune functions during systemic inflammation without an impact on survival. A pharmacologic beta-adrenergic blockade partly augmented the epinephrine-induced immune alterations and was associated with a pronounced increase of mortality. This effect was further augmented by a combination of epinephrine infusion and beta-adrenergic blockade. These data indicate that adrenergic mechanisms modulate cellular immune functions and survival during sepsis, with these effects being mediated via alpha- and beta-adrenergic pathways.     

辛伐他汀抑制大鼠实验性自身免疫性脑脊髓炎的实验研究

目的 探讨辛伐他汀(STATINS)对实验性自身免疫性脑脊髓炎IEAE)的作用及机理.方法 Wistar大鼠55只采用随机数字表法分为EAE组(15只)、STATINS组(15只)、雷公藤(TP)组(15只)、正常对照组(10只).使用STATINS干预EAE大鼠,以TP为阳性对照,观察大鼠P53蛋白、IL-6、TNF-α、TGF-β的表达变化.结果 与EAE组相比,STATINS组发病率降低、临床症状减轻、体质量下降减少、病灶数减少、潜伏期延长,而TP组临床症状减轻、病灶数减少,差异均有统计学意义(P＜0.05),TP组体质量变化、潜伏期、发病率无显变化,差异无统计学意义(P＞0.05);STATINS组IL-6和TNF-α的表达降低,P53蛋白和TGF-β的表达增高;TP组仅TNF-α的表达降低,差异均有统计学意义(P＜0.05).与TP组相比较,STATINS组P53蛋白与TGF-β的表达增加,差异有统计学意义(P＜0.05),而TNF-α及Ⅱ-6的表达差异无统计学意义(P＞0.05).结论 STATINS可以有效抑制EAE.其可能的机制是抑制IL-6和TNF-α等促炎症因子的表达,促进P53蛋白与TGF-β的表达,效果可能优于TP.     

Increased sleep fragmentation in experimental autoimmune encephalomyelitis

Sleep disturbance in patients with multiple sclerosis is prevalent and has multifactorial causes. In mice with experimental autoimmune encephalomyelitis (EAE), a model of multiple sclerosis, we determined the dynamic changes of sleep architecture and the interactions between sleep changes and EAE symptoms. The changes of sleep patterns were mainly reflected by altered sleep stage distribution and increased sleep fragmentation. Increased waking and decreased non-rapid eye movement sleep occurred after EAE onset and persisted through the symptomatic phase. There also was increased sleep state transition, indicating a reduction of sleep cohesiveness. Furthermore, the extent of sleep fragmentation correlated with the severity of disease. This is the first study of sleep characteristics in EAE mice demarcating specific changes related to the autoimmune disorder without confounding factors such as psychosocial impact and treatment effects. The reduction of sleep efficiency and cohesiveness supports the notion that enhancing sleep might facilitate the recovery of mice from EAE, pertinent to the multimodality treatment of multiple sclerosis.     

Increased thrombin inhibition in experimental autoimmune encephalomyelitis

Multiple sclerosis (MS) and its animal model, experimental autoimmune encephalomyelitis (EAE), are inflammatory diseases of the central nervous system (CNS). Activated coagulation factors are associated with inflammation and are elevated in the plasma of animals with EAE. Thrombin is a key coagulation factor and its major endogenous inhibitors are antithrombin III (ATIII) in the plasma and protease nexin 1 (PN-1) in the brain. We measured the capacity of brain homogenates to inhibit exogenous thrombin and the CNS levels of ATIII and PN-1 during the course of EAE. Acute EAE was induced in SJL/J mice by immunization with mouse spinal cord homogenates. On Days 8, 13, and 22 post-immunization, inhibition of exogenous thrombin activity was measured by a recently developed fluorimetric assay. PN-1 and ATIII were assayed both by immunohistochemistry and by immunoblots in the brain and spinal cord. Total brain thrombin inhibitory activity increased (32%) in EAE mice at the peak of clinical disease (Day 13, P=0.04 compared to controls). Brain ATIII also increased at the peak of disease (2.5-fold higher than controls, P=0.0001), and correlated significantly with clinical scores at all stages of disease (r=0.72, P=0.0068). In contrast, PN-1 elevations were more pronounced at the preclinical stage on Day 8 (3-fold higher than controls, P=0.01) than on Day 13 (1.4-fold higher, P=0.005). Increased brain thrombin inhibition at the clinical peak of EAE probably reflects increased influx of plasma thrombin inhibitors. Early PN-1 changes represent a potential target for thrombin modulating drugs in EAE and MS.     

Fas system up-regulation in experimental autoimmune encephalomyelitis

Experimental autoimmune encephalomyelitis (EAE) is a T-cell-mediated disorder characterized by infiltration of the central nervous system (CNS) by mononuclear cells and macrophages, and serves as a model for multiple sclerosis. In acute monophasic and relapsing remitting forms of EAE, the CNS inflammatory infiltrates are cleared within a few days and, simultaneously, animals recover from their clinical disability. The mechanisms for rapid disappearance of the inflammatory cells are not fully understood. Fas and Fas-ligand (Fas-L) molecules are thought to play an important role in the deletion of autoimmune reactive T cells through apoptosis. However, recent observations in transgenic lpr and gld mice show that mutations inactivating Fas and Fas-L respectively ameliorate signs of EAE despite persistence of immune cell infiltrates into the CNS. In the current study, the expression of Fas and Fas-L was investigated by immunochemistry and in situ hybridization during the course of EAE in DA rats that were actively immunized with syngenic spinal cord homogenate. CNS apoptotic cells were simultaneously examined using terminal transferase dUTP nick end-labeling techniques. During the acute phase of the disease, a significant proportion of CNS CD4+ cells (80%) and macrophages (50%) expressed Fas and Fas-L (80 and 60%, respectively). Simultaneously, about 20% of CD4+ cells and 30% of macrophages were found to be apoptotic. Some astrocytes and neurons also expressed Fas and Fas-L, although they did not appear to be apoptotic. These results further support a role for Fas-mediated lymphocyte and macrophage apoptosis in this model of CNS autoimmune disease but they also suggest a more complex role for Fas/Fas-L interactions in CNS autoimmunity, including resident cells.     

Keratan sulfate exacerbates experimental autoimmune encephalomyelitis

Proteoglycans (PGs) are the components of extracellular matrices in the central nervous system (CNS). Keratan sulfate (KS) is a glycosaminoglycan that is included in the KSPG that acts as an inhibitory factor in nerve regeneration after CNS injury. To investigate the role of KS in immune diseases, we induced experimental autoimmune encephalomyelitis (EAE) in mice that were deficient in the N‐acetylglucosamine (GlcNAc)‐6‐O‐sulfotransferase 1 (GlcNAc6ST1) gene (KS‐KO). KS‐KO mice developed less severe EAE and showed repressed recall response in the induction phase. Furthermore, GlcNAc6ST1 might have roles in the passage of the pathogenic lymphocytes through the blood–brain barrier via adhesion molecules. Thus, modulation of KS may become a treatment for neuroimmunological diseases. © 2015 Wiley Periodicals, Inc.     

Insulin-like growth factor-I treatment reduces immune cell responses in acute non-demyelinative experimental autoimmune encephalomyelitis

To test the effects of insulin-like growth factor-I (IGF-I) on clinical deficits, lesion severity, and immune cell responses in acute, non-demyelinative experimental autoimmune encephalomyelitis (EAE), we induced EAE in Lewis rats by passive transfer of an MBP-reactive T lymphocyte line. Four days after receiving 5 × 10⁵ MBPL-1 T cells intravenously, ten pairs of rats had the same mild degree of tail and hind limb weakness. Ten were given 300 μg IGF-I i.v. twice daily for 6 days, and the other 10 received the same volume of 0.89% NaCl. Pairs of rats were sacrificed after 4 days and 6 days of IGF-I and placebo treatment and spinal cord sections were processed for immunostaining, in situ hybridization, and morphological examination. IGF-I treatment decreased clinical deficits, lesion numbers, and lesion areas significantly. Numbers of CD4-positive T cells, α/β TCR-positive cells, and ED-1-positive macrophages were also significantly reduced by IGF-I treatment. Similar reductions were found in our second trial, when 11 days of placebo and IGF-I injections began the day after transfer. No demyelination was observed in either toluidine blue-stained semithin sections or in sections immunostained with an antibody raised against myelin basic protein (MBP). We conclude that IGF-I-induced reductions in immune cell responses can occur in the absence of demyelination and are of major importance in decreasing clinical deficits and lesion severity in EAE. If IGF-I has similar effects in multiple sclerosis, we think that it will be useful therapeutically. © 1997 Wiley-Liss Inc.     

Radiometric assessment of experimental autoimmune encephalomyelitis in mice

The cell-mediated inflammatory component of experimental autoimmune encephalomyelitis (EAE) in mice is measured by the radioisotopic technique. Mice are challenged with autologous spinal cord homogenate in Freund's complete adjuvant and at various time intervals after such immunization given [125I]5-iodo-2'-deoxyuridine which is incorporated into the mononuclear cell pool. The degree of cell-mediated inflammation is determined by radiometry of the brain and spinal cord tissues. Increased radiolabelling is detected in the brains 2 days prior to the onset of clinical signs of EAE; increased radioactivity of the spinal cord is concomitant with clinical signs. This technique is useful in staging the extent of EAE and may prove to be a powerful tool in studying cell-mediated reactions in other autoimmune diseases.     

Critical role of preproenkephalin in experimental autoimmune encephalomyelitis

Experimental autoimmune encephalomyelitis (EAE) is an organ-specific autoimmune disease model used to investigate mechanisms involved in the activation of self-reactive T cells. Preproenkephalin (PPNK) is the gene that encodes the protein proenkephalin A that has been detected in the brain, adrenal cells and cells of the immune system. In this paper, whether PPNK plays a role in the development of EAE was investigated. PPNK-deficient and wild-type mice were immunized with the MOG(35-55) peptide and the development of EAE observed. Our results show that PPNK-deficient mice developed less severe clinical signs of disease than wild-type mice, and with lower incidence. MOG(35-55)-specific T cells from PPNK-deficient and wild-type mice produced IFNgamma and TNFalpha but no IL-4 or IL-10, indicative of a Th1 phenotype. However, the numbers of MOG(35-55)-specific IFNgamma-producing cells from immunized PPNK-deficient mice were largely reduced at early stages of disease. Interestingly, there was no difference in clinical signs or infiltrating mononuclear cells in the CNS between wild-type and PPNK-deficient mice at the later stage of disease. Our results suggest that PPNK accelerates the generation of autoimmune IFNgamma-producing T cells and MOG(35-55)-induced EAE.     

阿托伐他汀对实验性自身免疫性脑脊髓炎的治疗作用

目的 观察不同剂量阿托伐他汀对实验性自身免疫性脑脊髓炎(EAE)的治疗效果,探讨其作用机制.方法 采用Wistar大鼠建立EAE模型,分别应用每日每千克体重2、8 mg的阿托伐他汀进行治疗,观察其对大鼠发病率、复发率、神经功能评分和组织病理改变的影响及程度,并测定基质金属蛋白酶-9(MMP-9)和IL-4在体内的表达及含量变化.结果 EAE模型组与大剂量治疗组相比较,神经功能评分有显著改善,发病率由76.67%下降至33.33%(P=O.008),脊髓组织中血管袖套数目由3.2±1.1减少为1.3±0.4(P=0.01),血清中IL-4的含量由(0.35±0.12)ng/ml显著提高至(0.68±0.23)ng/ml(P=0.05),MMP-9在组织中的表达由37±7减少至26±5(P=0.001).结论 阿托伐他汀能改善EAE的临床表现,减轻组织损伤,其作用可能与减少MMP-9和提高IL-4含量有关.     

Suppression of experimental autoimmune encephalomyelitis by sulfasalazine

It has recently been suggested that the sulfidopeptide leukotriene C4 (LTC4), a 5-lipoxygenase product of the arachidonic acid metabolism and one of the most potent mediators of vascular permeability, might be involved in the pathogenesis of experimental autoimmune encephalomyelitis (EAE) and multiple sclerosis (MS). Subsequently, 20 guinea pigs with EAE were treated with sulfasalazine, a substance with a proved leukotriene inhibiting effect, which has previously been described as exerting beneficial effects in patients with inflammatory bowel disease and rheumatoid arthritis. The sulfasalazine-treated guinea pigs showed a significantly better clinical outcome, as well as a significantly lower histological inflammation score compared with 19 controls.     

Inheritance of susceptibility to experimental autoimmune encephalomyelitis

Experimental autoimmune encephalomyelitis is a disease of the central nervous system that can be readily induced in a variety of species by immunization with myelin proteins. It is one of the most commonly studied models of cell-mediated autoimmune disease and consequently has been important in the elucidation of many immunological functions in vivo. Nevertheless, very little is understood about the genetic and environmental factors that control the disease. Several groups have begun undertaking systematic genetic analyses in mice to identify loci that associate with increased susceptibility to disease. In this review, we will summarize the work that has been done to understand the genetic predisposition that makes certain inbred animals susceptible to disease and others resistant, and we will discuss some of the difficulties in the genetic analysis that have arisen due to the complexities of this disease model. © 1996 Wiley-Liss, Inc.     

Administration of nitric oxide synthase inhibitors in experimental autoimmune neuritis and experimental autoimmune encephalomyelitis

The nitric oxide (NO) synthase pathway is activated during experimental autoimmune inflammation of the central nervous system, and administration of aminoguanidine, an inhibitor of the cytokine-inducible NO synthase (NOS), ameliorated the disease course of autoimmune encephalomyelitis in the SJL mouse. We studied the role of nitric oxide synthase (NOS) in the pathogenesis of experimental autoimmune neuritis (EAN) and experimental autoimmune encephalomyelitis (EAE) in the Lewis rat. N^G- -monomethyl-arginine ( -NMMA), a competitive inhibitor of NOS, partially suppressed T cell line-mediated EAN, but not myelin-induced EAN, myelin basic protein (MBP)-induced EAE, or T cell line-mediated EAE. Aminoguanidine (AG), a selective inhibitor of the cytokine-inducible NOS, enhanced MBP-induced EAE, but had no significant effects on myelin-induced EAN. Two other NOS inhibitors, nitro-arginine methyl-ester and N-nitro arginine, had only little or no effects in EAN and EAE. The administration of NOS inhibitors showed some striking effects in EAN and EAE, but the observed diversity of actions points to a much more complex role of the NO pathway than previously suggested.     

Bladder dysfunction in mice with experimental autoimmune encephalomyelitis

The vast majority of patients with multiple sclerosis (MS) develop bladder control problems including urgency to urinate, urinary incontinence, frequency of urination, and retention of urine. Over 60% of MS patients show detrusor-sphincter dyssynergia, an abnormality characterized by obstruction of urinary outflow as a result of discoordinated contraction of the urethral sphincter muscle and the bladder detrusor muscle. In the current study we examined bladder function in female SWXJ mice with different defined levels of neurological impairment following induction of experimental autoimmune encephalomyelitis (EAE), an animal model of central nervous system inflammation widely used in MS research. We found that EAE mice develop profound bladder dysfunction characterized by significantly increased micturition frequencies and significantly decreased urine output per micturition. Moreover, we found that the severity of bladder abnormalities in EAE mice was directly related to the severity of clinical EAE and neurologic disability. Our study is the first to show and characterize micturition abnormalities in EAE mice thereby providing a most useful model system for understanding and treating neurogenic bladder.