多发性硬化疾病及模型小鼠中疾病相关细胞因子和转录因子研究进展

多发性硬化症（multiple sclerosis,MS）是一种原发于中枢神经系统的炎症性脱髓鞘疾病。实验性自身免疫性脑脊髓炎（experimental autoimmune encephalomyelitis,EAE）与MS有相似的临床症状和病理特征,是被广泛应用于人类疾病研究的动物模型。MS确切的发病机制尚不清楚,但普遍认为是在易感基因的基础上,受环境因素触发,由CD4＋T细胞介导的中枢神经系统（centralnervous system,CNS）自身免疫性疾病。初始CD4＋T细胞在T细胞受体介导下活化,继而可分化为至少4个主要亚型,分别为TH1、TH2、TH17和iTreg细胞,参与不同类型的免疫应答。细胞因子和转录因子网络对CD4＋T细胞分化和效应细胞因子产物有重要意义。该文综述了各相关细胞因子和转录因子在CD4＋T细胞向不同亚型分化及MS/EAE发病过程中的相互作用和调控,揭示各因子在这些过程中的作用,有助于进一步研究和治疗MS。     

A CB2 Receptor Agonist Reduces the Production of Inflammatory Mediators and Improves Locomotor Activity in Experimental Autoimmune Encephalomyelitis

Background:Cannabinoids (CBs) have been found to regulate the immune system, affect innate and adaptive immune responses, and reduce inflammatory reactions. This study assessed the therapeutic effects of GW-405833 synthetic CB2 agonist on inflammatory factors as well as locomotor activity in experimental autoimmune encephalomyelitis (EAE).Methods:In this experimental study, 48 adult male C57BL/6 mice were randomly and equally assigned to eight groups. By injecting 250 mg of MOG35-55 peptide, EAE was induced. Every other day for 17 days after EAE onset, EAE-afflicted mice in groups 1–3 received an intraperitoneal injection of GW-405833 at a dose of 3, 10, and 30 mg/kg, respectively. Clinical status and locomotor activity, measured using the beam walking assay, were assessed every other day during the first 17 days after EAE onset. Mice were euthanized in day 17th of treatment and the serum levels of the IL-1β, IL-12, CRP, and TNF-α proinflammatory cytokines as well as IL-4 and TGF-β anti-inflammatory cytokines were measured by ELISA method.Results:Clinical manifestations of EAE in groups 2 and 3 were significantly milder than group 4 and locomotor activity in groups 1–3 was significantly better than group 4 in days 5–17 (p< 0.05). GW-405833 also significantly decreased the levels of IL-12, TNF-α, and CRP and significantly increased the levels of IL-4 and TGF-β but had no significant effects on the level of IL-1β. GW-405833 was not associated with significant side effects.Conclusion:The CB2 receptor agonist GW-405833, improves clinical conditions and reduces inflammation in mice with EAE.Key Words: Clinical evaluation, Experimental autoimmune encephalomyelitis, GW-405833, Locomotor activity, Multiple sclerosis, Proinflammatory cytokines     

AKP-11 - A Novel S1P1 Agonist with Favorable Safety Profile Attenuates Experimental Autoimmune Encephalomyelitis in Rat Model of Multiple Sclerosis

Sphingosine-1-phosphate receptor 1 (S1P1) mediated regulation of lymphocyte egress from lymphoid organs is recognized as the mechanism of FTY720 (Fingolimod, Gilenya) efficacy in relapsing-remitting forms of multiple sclerosis (RRMS). In this study we describe a novel S1P1 agonist AKP-11, next generation of S1P1 agonist, with immunomodulatory activities in cell culture model and for therapeutic efficacy against an animal model of MS, i.e. experimental autoimmune encephalomyelitis (EAE) but without the adverse effects observed with FTY720. Like FTY720, AKP-11 bound to S1P1 is internalized and activates intracellular AKT and ERKs cellular signaling pathways. In contrast to FTY720, AKP-11 mediated S1P1 downregulation is independent of sphingosine kinase activity indicating it to be a direct agonist of S1P1. The S1P1 loss and inhibition of lymphocyte egress by FTY720 leads to lymphopenia. In comparison with FTY720, oral administration of AKP-11 caused milder and reversible lymphopenia while providing a similar degree of therapeutic efficacy in the EAE animal model. Consistent with the observed reversible lymphopenia with AKP-11, the S1P1 recycled back to cell membrane in AKP-11 treated cells following its withdrawal, but not with withdrawal of FTY720. Accordingly, a smaller degree of ubiquitination and proteolysis of S1P1 was observed in AKP-11 treated cells as compared to FTY720. Consistent with previous observations, FTY720 treatment is associated with adverse effects of bradycardia and lung vascular leaks in rodents, whereas AKP-11 treatment had undetectable effects on bradycardia and reduced lung vascular leaks as compared to FTY720. Taken together, the data documents that AKP-11 treatment cause milder and reversible lymphopenia with milder adverse effects while maintaining therapeutic efficacy similar to that observed with FTY720, thus indicating therapeutic potential of AKP-11 for treatment of MS and related autoimmune disorders.     

Spasticity Treatment Ameliorates the Efficacy of Melatonin Therapy in Experimental Autoimmune Encephalomyelitis (EAE) Mouse Model of Multiple Sclerosis

Multiple sclerosis (MS) is a progressive inflammatory demyelinating disease in the central nervous system (CNS). Melatonin is an effective treatment in MS patients and experimental autoimmune encephalomyelitis (EAE), a mouse model of MS. Melatonin secretion peaks at 2 AM, concomitant with the time at which the muscles are resting and the body is exerting its antioxidant activity. The current study was designed to investigate combination treatment of baclofen, a muscle relaxant drug, and melatonin in EAE mice. Results showed that melatonin (Mel) alone or in combination with baclofen (Bac + Mel) reduced clinical scores and demyelination by significantly increasing myelin oligodendrocyte glycoprotein (MOG) levels, a marker for mature oligodendrocytes, compared to EAE mice. Moreover, Mel or Bac + Mel therapy caused a significant increase in IL-4 serum levels, an anti-inflammatory cytokine, whereas IFN-γ serum levels, a pro-inflammatory cytokine, were significantly reduced. On the other hand, Mel or Bac + Mel caused a significant reduction in malondialdehyde (MDA) levels, a marker of oxidative stress, in comparison to EAE mice. In contrast, the activity of antioxidant enzymes catalase (CAT) and superoxide dismutase (SOD) was significantly increased in Mel and Bac + Mel groups. In summary, combination therapy improved clinical scores and tend to enhance the efficiency of melatonin treatment by further promoting remyelination, decreasing inflammation, and stimulating the activity of antioxidant enzymes, which suggests that prior spasticity treatment increases the efficacy of melatonin therapy in EAE mouse model of MS. Further experimental and clinical studies are needed to ensure the beneficial role of this combination strategy.     

Cinnamon Ameliorates Experimental Allergic Encephalomyelitis in Mice via Regulatory T Cells: Implications for Multiple Sclerosis Therapy

Upregulation and/or maintenance of regulatory T cells (Tregs) during an autoimmune insult may have therapeutic efficacy in autoimmune diseases. Although several immunomodulatory drugs and molecules are available, most present significant side effects over long-term use. Cinnamon is a commonly used natural spice and flavoring material used for centuries throughout the world. Here, we have explored a novel use of cinnamon powder in protecting Tregs and treating the disease process of experimental allergic encephalomyelitis (EAE), an animal model of MS. Oral feeding of cinnamon (Cinnamonum verum) powder suppresses clinical symptoms of relapsing-remitting EAE in female PLP-TCR transgenic mice and adoptive transfer mouse model. Cinnamon also inhibited clinical symptoms of chronic EAE in male C57/BL6 mice. Dose-dependent study shows that cinnamon powder at a dose of 50 mg/kg body wt/d or higher significantly suppresses clinical symptoms of EAE in mice. Accordingly, oral administration of cinnamon also inhibited perivascular cuffing, maintained the integrity of blood-brain barrier and blood-spinal cord barrier, suppressed inflammation, normalized the expression of myelin genes, and blocked demyelination in the central nervous system of EAE mice. Interestingly, cinnamon treatment upregulated Tregs via reduction of nitric oxide production. Furthermore, we demonstrate that blocking of Tregs by neutralizing antibodies against CD25 abrogates cinnamon-mediated protection of EAE. Taken together, our results suggest that oral administration of cinnamon powder may be beneficial in MS patients and that no other existing anti-MS therapies could be so economical and trouble-free as this approach.     

Analysis of the Gadolinium retention in the Experimental Autoimmune Encephalomyelitis (EAE) murine model of Multiple Sclerosis

ObjectivesThe aim of this study is to quantitatively investigate, at the preclinical level, the extent of Gd retention in the CNS, and peripheral organs, of immune-mediated murine models (Experimental Autoimmune Encephalomyelitis –EAE) of Multiple Sclerosis, compared to control animals, upon the injection of gadodiamide. The influence of the Gadolinium Based Contrast Agent administration timing during the course of EAE development is also monitored.MethodsEAE mice were injected with three doses (1.2 mmol/kg each) of gadodiamide at three different time points during the EAE development and sacrificed after 21 or 39 days. Organs were collected and the amount of Gd was quantified through Inductively Coupled Plasma-Mass Spectrometry. Transmission electron microscopy (TEM) and MRI techniques were applied to add spatial and qualitative information to the obtained results.ResultsIn the spinal cord of EAE group, 21 days after gadodiamide administration, a significantly higher accumulation of Gd occurred. Conversely, in the encephalon, a lower amount of Gd retention was reached, even if differences emerged between EAE and controls mice. After 39 days, the amounts of retained Gd markedly decreased. TEM validated the presence of Gd in CNS. MRI of the encephalon at 7.1T did not highlight any hyper intense region.ConclusionIn the spinal cord of EAE mice, which is the mostly damaged region in this specific animal model, a preferential but transient accumulation of Gd is observed. In the encephalon, the Gd retention could be mostly related to inflammation occurring upon immunization rather than to demyelination.     

Essential Role of NK Cells in IgG Therapy for Experimental Autoimmune Encephalomyelitis

Intravenous immunoglobulin has long been used in treating autoimmune diseases, although mechanisms remain uncertain. Activating Fcγ receptors are receptors of IgG and reported to be essential in intravenous immunoglobulin (IVIG) therapy. Therefore, we hypothesized natural killer (NK) cells, which express abundant activating Fcγ receptors, are the potential cellular target. In experimental autoimmune encephalomyelitis (EAE), we demonstrated that IgG suppressed disease development in intact, but not in NK cell depleted mice. Adoptive transfer of IgG-treated NK cell could protect mice against EAE, and suppressed interferon γ and interleukin 17 production. The percentage of CD4⁺Foxp3⁺ regulatory T cells was significantly increased. The increase of regulatory T cells was also observed in IgG-treated EAE mice but not in NK cell depleted mice. In vitro experiments confirmed that IgG-treated NK cells enhanced regulatory T cell induction from naïve CD4⁺ T cells. Interestingly, cells from draining lymph nodes produced more interleukin 2 after the adoptive transfer of IgG-treated NK cells. We neutralized interleukin 2 and the induction of CD4⁺Foxp3⁺ T cells by IgG-treated NK cells was significantly reduced. To our knowledge, we identified for the first time the critical role of NK cells in the mechanism of IgG-induced induction of Treg cells in treatment of autoimmunity.     

Prenatal Stress Impairs Spinal Cord Oligodendrocyte Maturation via BDNF Signaling in the Experimental Autoimmune Encephalomyelitis Model of Multiple Sclerosis

One of the most substantial and established environmental risk factors for neurological and psychiatric disorders is stress exposure, whose detrimental consequences hinge on several variables including time. In this regard the gestational period is known to present an intrinsic vulnerability to environmental insults and thus stressful events during pregnancy can lead to severe consequences on the offspring’s brain development with long-term repercussions throughout adulthood. On this basis, we investigated the long-lasting impact of prenatal stress exposure on the susceptibility to the experimental autoimmune encephalomyelitis (EAE), a well-established murine model of multiple sclerosis. Although stress is considered a triggering factor for this chronic, progressive, autoimmune disease, little is known about the underlying mechanisms. To this end, EAE was induced by immunization with MOG35-55/CFA and pertussis toxin administration in adult female C57BL/6 mice born from control or stressed dams exposed to restraint stress during the last days of gestation. Our results demonstrate that gestational stress induces a marked increase in the severity of EAE symptoms in adulthood. Further, we highlight an altered maturation of oligodendrocytes in the spinal cord of prenatally stressed EAE mice, as indicated by the higher levels of GPR17, a marker of immature oligodendrocyte precursor cells. These behavioral and molecular alterations are paralleled by changes in the expression and signaling of the neurotrophin BDNF, an important mediator of neural plasticity that may contribute to stress-induced impaired remyelination. Since several already marketed drugs are able to modulate BDNF levels, these results pave the way to the possibility of repositioning these drugs in multiple sclerosis.

     

ASP4058, a Novel Agonist for Sphingosine 1-Phosphate Receptors 1 and 5, Ameliorates Rodent Experimental Autoimmune Encephalomyelitis with a Favorable Safety Profile

Sphingosine-1-phosphate (S1P) is a biologically active sphingolipid that acts through the members of a family of five G protein-coupled receptors (S1P₁–S1P₅). S1P₁ is a major regulator of lymphocyte trafficking, and fingolimod, whose active metabolite fingolimod phosphate acts as a nonselective S1P receptor agonist, exerts its immunomodulatory effect, at least in part, by regulating the lymphocyte trafficking by inducing down regulation of lymphocyte S1P₁. Here, we detail the pharmacological profile of 5-{5-[3-(trifluoromethyl)-4-{[(2S)-1,1,1-trifluoropropan-2-yl]oxy}phenyl]-1,2,4-oxadiazol-3-yl}-1H-benzimidazole (ASP4058), a novel next-generation S1P receptor agonist selective for S1P₁ and S1P₅. ASP4058 preferentially activates S1P₁ and S1P₅ compared with S1P_{2, 3, 4} in GTPγS binding assays in vitro. Oral administration of ASP4058 reduced the number of peripheral lymphocytes and inhibited the development of experimental autoimmune encephalomyelitis (EAE) in Lewis rats. Further, ASP4058 prevented relapse of disease in a mouse model of relapsing-remitting EAE. Although these immunomodulatory effects were comparable to those of fingolimod, ASP4058 showed a wider safety margin than fingolimod for bradycardia and bronchoconstriction in rodents. These observations suggest that ASP4058 represents a new therapeutic option for treating multiple sclerosis that is safer than nonselective S1P receptor agonists such as fingolimod.     

Detecting Deoxyhemoglobin in Spinal Cord Vasculature of the Experimental Autoimmune Encephalomyelitis Mouse Model of Multiple Sclerosis Using Susceptibility MRI and Hyperoxygenation

Susceptibility-weighted imaging (SWI) detects hypointensities due to iron deposition and deoxyhemoglobin. Previously it was shown that SWI detects hypointensities in the experimental autoimmune encephalomyelitis (EAE) model of multiple sclerosis (MS), most of which are due to intravascular deoxyhemoglobin, with a small proportion being due to iron deposition in the central nervous system parenchyma and demyelination. However, animals had to be sacrificed to differentiate these two types of lesions which is impractical for time course studies or for human application. Here, we proposed altering the inspired oxygen concentration during imaging to identify deoxyhemoglobin-based hypointensities in vivo. SWI was performed on lumbar spinal cords of naive control and EAE mice using 30% O₂ then 100% O2. Some mice were imaged using 30% O₂, 100% O₂ and after perfusion. Most SWI-visible hypointensities seen with 30% O₂ changed in appearance upon administration of 100% O₂, and were not visible after perfusion. That hypointensities changed with hyperoxygenation indicates that they were caused by deoxyhemoglobin. We show that increasing the inspired oxygen concentration identifies deoxyhemoglobin-based hypointensities in vivo. This could be applied in future studies to investigate the contribution of vascular-based hypointensities with SWI in EAE and MS over time.     

Autoimmune Thyroid Disease in the Use of Alemtuzumab for Multiple Sclerosis: A Review

ObjectiveThe monoclonal antibody alemtuzumab has been demonstrated to reduce the risks of relapse and accumulation of sustained disability in multiple sclerosis (MS) patients when compared to β-interferon. The development of autoimmune diseases, including thyroid disease, has been reported in the literature with a frequency of 20 to 30%. In this article, we describe 4 cases of alemtuzumab-induced thyroid disease in patients with MS. We also performed a systematic review of the available literature.MethodsFour patients who had received alemtuzumab for MS and subsequently developed thyroid dysfunction are presented. We compared our patients' clinical courses and outcomes to established disease patterns. We also undertook a systematic review of the published literature.ResultsAll 4 patients presented with initial hyperthyroidism associated with elevated thyroid-stimulating hormone (TSH) receptor antibodies (TRAb). In 2 cases, hyperthyroidism did not remit after a total of 24 months of carbimazole therapy, and they subsequently underwent subtotal thyroidectomy. The third case subsequently developed biochemical hypothyroidism and required thyroxine replacement, despite having a markedly raised initial TRAb titer. Autoimmunity following alemtuzumab therapy in MS appears to occur as part of an immune reconstitution syndrome and is more likely in smokers who have a family history of autoimmune disease.ConclusionManagement of alemtuzumab-induced thyroid disease is similar to the management of “wild-type” Graves’ disease. The use of alemtuzumab in this setting will necessitate close monitoring of thyroid function and early intervention when abnormalities are developing. (Endocr Pract. 2013;19:821-828)     

Theiler's Murine Encephalomyelitis Virus (TMEV)-Induced Demyelination: A Model for Human Multiple Sclerosis

Numerous studies suggest that a viral infection, on the appropriate genetic background, may play an important pathogenetic role in the development of multiple sclerosis (MS). Among the several viral models of demyelination that have been investigated during the past two decades, Theiler's murine encephalomyelitis virus (TMEV)-induced demyelinating disease has emerged as one of the best because, similarly to MS, it is based on a combined viral-immune pathogenesis. This review highlights the following salient features of this model. TMEV-induced demyelinating disease is a chronic process, lasting for the life of the animals. Lesions consist of well-demarcated plaques of demyelination, which are strictly related to the presence of mononuclear cell infiltrates. Myelin degeneration is not due to direct viral cytopathic effects, but is rather dependent on the host immune response. Susceptibility/resistance to the disease is genetically regulated, and multiple genes both in and outside the major histocompatibility complex appear to be involved. The best immunological parameter that correlates with susceptibility is the ability of a murine strain to mount a delayed-type hypersensitivity (DTH) response to one or more viral epitopes. The importance of the DTH response against the virus in the pathogenesis of the disease is supported by the prevalent role of TH1 T-helper cells, known to be responsible for DTH responses, in inflamed CNS tissues. The role of DTH responses in the pathogenesis of demyelination is supported by the presence of numerous macrophages in affected CNS and by a direct relationship between the number of macrophages, their persistence in tissues, and the severity of lesions. Macrophages, in addition, are the main reservoir of the virus in the CNS, and their infectability correlates with susceptibility to the disease process. It is hypothesized that following the DTH response to the virus, activated lymphocytes recruit other inflammatory cells, particularly macrophages, into the infected CNS tissues. These nonspecifically recruited cells would secrete a number of proinflammatory molecules and proteases that would destroy myelin as a “bystander effect.”     

Genetic Background Can Result in a Marked or Minimal Effect of Gene Knockout (GPR55 and CB2 Receptor) in Experimental Autoimmune Encephalomyelitis Models of Multiple Sclerosis

Endocannabinoids and some phytocannabinoids bind to CB₁ and CB₂ cannabinoid receptors, transient receptor potential vanilloid one (TRPV1) receptor and the orphan G protein receptor fifty-five (GPR55). Studies using C57BL/10 and C57BL/6 (Cnr2 ^tm1Zim) CB₂ cannabinoid receptor knockout mice have demonstrated an immune-augmenting effect in experimental autoimmune encephalomyelitis (EAE) models of multiple sclerosis. However, other EAE studies in Biozzi ABH mice often failed to show any treatment effect of either CB₂ receptor agonism or antagonism on inhibition of T cell autoimmunity. The influence of genetic background on the induction of EAE in endocannabinoid system-related gene knockout mice was examined. It was found that C57BL/6.GPR55 knockout mice developed less severe disease, notably in female mice, following active induction with myelin oligodendrocyte glycoprotein 35-55 peptide. In contrast C57BL/6.CB₂ (Cnr2 ^Dgen) receptor knockout mice developed augmented severity of disease consistent with the genetically and pharmacologically-distinct, Cnr2 ^tm1Zim mice. However, when the knockout gene was bred into the ABH mouse background and EAE induced with spinal cord autoantigens the immune-enhancing effect of CB₂ receptor deletion was lost. Likewise CB₁ receptor and transient receptor potential vanilloid one knockout mice on the ABH background demonstrated no alteration in immune-susceptibility, in terms of disease incidence and severity of EAE, in contrast to that reported in some C57BL/6 mouse studies. Furthermore the immune-modulating influence of GPR55 was marginal on the ABH mouse background. Whilst sedative doses of tetrahydrocannabinol could induce immunosuppression, this was associated with a CB₁ receptor rather than a CB₂ receptor-mediated effect. These data support the fact that non-psychoactive doses of medicinal cannabis have a marginal influence on the immune response in MS. Importantly, it adds a note of caution for the translational value of some transgenic/gene knockout and other studies on low-EAE susceptibility backgrounds with inconsistent disease course and susceptibility.     

Inosine,an Endogenous Purine Nucleoside,Suppresses Immune Responses and Protects Mice from Experimental Autoimmune Encephalomyelitis: a Role for A2A Adenosine Receptor

Multiple sclerosis (MS) is a T cell autoimmune, inflammatory, and demyelinating disease of the central nervous system (CNS). Currently available therapies have partially effective actions and numerous side reactions. Inosine, an endogenous purine nucleoside, has immunomodulatory, neuroprotective, and analgesic properties. Herein, we evaluated the effect of inosine on the development and progression of experimental autoimmune encephalomyelitis (EAE), an experimental model of MS. Inosine (1 or 10 mg/kg, i.p.) was administrated twice a day for 40 days. Immunological and inflammatory responses were evaluated by behavioral, histological, immunohistochemical, ELISA, RT-PCR, and Western blotting analysis. The administration of inosine exerted neuroprotective effects against EAE by diminishing clinical signs, including thermal and mechanical hyperalgesia, as well as weight loss typical of the disease. These beneficial effects of inosine seem to be associated with the blockade of inflammatory cell entry into the CNS, especially lymphocytes, thus delaying the demyelinating process and astrocytes activation. In particular, up-regulation of IL-17 levels in the secondary lymphoid tissues, a result of EAE, was prevented by inosine treatment in EAE mice. Additionally, inosine consistently prevented A2AR up-regulation in the spinal cord, likely, through an ERK1-independent pathway. Altogether, these results allow us to propose that this endogenous purine might be a putative novel and helpful tool for the prevention of autoimmune and neurodegenerative diseases, such as MS. Thus, inosine could have considerable implications for future therapies of MS, and this study may represent the starting point for further investigation into the role of inosine and adenosinergic receptors in neuroinflammation processes.

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Graphical Abstract Preventive treatment with inosine inhibits the development and progression of EAE in C57Bl/6 mice. Furthermore, neuroinflammation and demyelinating processes were blocked by inosine treatment. Additionally, inosine consistently inhibited IL-17 levels in peripheral lymphoid tissue, as well as IL-4 levels and A2AR up-regulation in the spinal cord, likely, through an ERK1-independent pathway. EAE: experimental autoimmune encephalomyelitis; MS: multiple sclerosis; A2AR: adenosine A2A receptor; IL-17: interleukin-17; IL-4: interleukin-4

     

Genetic Markers for Personalized Therapy of Polygenic Diseases: Pharmacogenetics of Multiple Sclerosis

Molecular Biology - Pharmacogenetics (PG) investigates the inherited variants of the human genome that underlie individual differences in drug metabolic transformation, delivery, and mechanism of...