髓鞘少突胶质细胞糖蛋白抗体在多发性硬化中的意义

目的探讨髓鞘少突胶质细胞糖蛋白(MOG)抗体与多发性硬化(MS)临床表现及复发缓解型MS(RRMS)复发的关系。方法采用酶联免疫吸附法(ELISA)对60例MS、23例其他炎性神经疾病(OIND)、29例非炎性神经疾病(NIND)以及50例神经系统正常的对照(NC)患者血清及脑脊液(CSF)MOG抗体进行检测。结果MS患者CSFMOG抗体阳性率为28.3%(17/60),明显高于NC组[2%(1/50)]和NIND组[0%(0/29)],但与OIND组[21.7%(5/23)]比较差异无统计学意义。各组血清MOG抗体均为阴性。抗体阳性率急性活动期为31.8%(14/44),与稳定期[18.75%(3/16)]比较差异无统计学意义。CSFMOG抗体阳性的RRMS患者复发时间早于阴性患者,且其第1、2年复发率均高于阴性患者。结论在部分MS患者中枢神经系统内存在异常的MOG特异性B细胞免疫应答,且CSFMOG抗体对RRMS的复发有一定预测作用。     

NAD+ Availability and Proteotoxicity

It has been shown that NAD⁺ availability is important for neuronal survival following ischemia (Liu et al., Neuromolecular Med 11:28–42, 2009). It is proposed here that NAD⁺ may also control proteotoxicity by influencing both formation and catabolism of altered proteins. It is suggested that low NAD⁺ availability promotes synthesis of methylglyoxal (MG) which can induce formation of glycated proteins, ROS, and dysfunctional mitochondria. That glyoxalase overexpression and carnosine are both protective against MG and ischemic injury support this proposal. Recognition and elimination of altered proteins is enhanced by NAD⁺ through effects on stress protein expression and autophagy.     

Role of perforin secretion from CD8+ T-cells in neuronal cytotoxicity in multiple sclerosis

Objectives: Multiple sclerosis (MS) is the most prevalent autoimmune disease of the central nervous system, and is characterized by inflammation and myelin damage. The immune system initiates the autoimmune response, although the mechanisms of neuronal damage have not been elucidated. The purpose of the present study was to investigate autoreactive CD4+ and CD8⁺ T lymphocytes, in conjunction with other inflammatory cells and cytokines in active MS lesions.

Methods: EAE animal models was established by plantar injections of MBP (200 μg per rat). Purified CD4+ or CD8+ T-cells were isolated from heparinized peripheral blood (EAE animals and control animals) via negative selection. To examine effects of presence of autoreactive CD4+ and CD8+ T lymphocytes, we carried out ELISA, Western blot analysis and TUNEL. In addition, we examined the direct effects of various factors on neuronal cell death using MTT assay.

Results: The data revealed that CD8+ T-cells were more toxic to neurons compared to CD4+ T-cells, in both the MBP and EAE conditions. Bax was greater increased when neurons were co-cultured with CD8+ T-cells in the MBP group. There is a significant increase in IL-17 secretion by CD4+ T-cells in both the MBP group and EAE group. Neuronal viability were affected by Perforin (1.5 μg/mL).

Conclusion: The present study extends previous research by demonstrating the role of CD8+ T-cells in MS and supports perforin secretion by CD8+ T-cells as a potential therapeutic factor. Furthermore, we determined that CD4⁺ T-cells can enhance CD8⁺ T-cell neuronal cytotoxicity via induction of intense inflammation.     

Clinical and Radiological Features of Myelin Oligodendrocyte Glycoprotein-Associated Myelitis in Adults

Antibodies against myelin oligodendrocyte glycoprotein (MOG-IgG) have recently been established as a biomarker for MOG-antibody-associated disease (MOGAD), which is a distinct demyelinating disease of the central nervous system. Among the diverse clinical phenotypes of MOGAD, myelitis is the second-most-common presentation in adults, followed by optic neuritis. While some features overlap, there are multiple reports of distinctive clinical and radiological features of MOG-IgG-associated myelitis, which are useful for differentiating MOGAD from both multiple sclerosis and neuromyelitis optica spectrum disorder. In this review we summarize the clinical and radiographic characteristics of MOG-IgG-associated myelitis with a particular focus on adult patients.     

NAD+-dependent mechanisms of disturbances of viability of brain cells during the acute period of hypoxic-ischemic perinatal injury

Using a model of perinatal hypoxic-ischemic injury of rat brain we have found the patterns of changes in the activity of ADP ribosyl cyclase in brain cells that determine the specific features of programmed cell death and maintenance of the intracellular NAD⁺ homeostasis.     

Nicotinamide Prevents NAD+ Depletion and Protects Neurons Against Excitotoxicity and Cerebral Ischemia: NAD+ Consumption by SIRT1 may Endanger Energetically Compromised Neurons

Neurons require large amounts of energy to support their survival and function, and are therefore susceptible to excitotoxicity, a form of cell death involving bioenergetic stress that may occur in several neurological disorders including stroke and Alzheimer’s disease. Here we studied the roles of NAD⁺ bioenergetic state, and the NAD⁺-dependent enzymes SIRT1 and PARP-1, in excitotoxic neuronal death in cultured neurons and in a mouse model of focal ischemic stroke. Excitotoxic activation of NMDA receptors induced a rapid decrease of cellular NAD(P)H levels and mitochondrial membrane potential. Decreased NAD⁺ levels and poly (ADP-ribose) polymer (PAR) accumulation in nuclei were relatively early events (<4 h) that preceded the appearance of propidium iodide- and TUNEL-positive cells (markers of necrotic cell death and DNA strand breakage, respectively) which became evident by 6 h. Nicotinamide, an NAD⁺ precursor and an inhibitor of SIRT1 and PARP1, inhibited SIRT1 deacetylase activity without affecting SIRT1 protein levels. NAD⁺ levels were preserved and PAR accumulation and neuronal death induced by excitotoxic insults were attenuated in nicotinamide-treated cells. Treatment of neurons with the SIRT1 activator resveratrol did not protect them from glutamate/NMDA-induced NAD⁺ depletion and death. In a mouse model of focal cerebral ischemic stroke, NAD⁺ levels were decreased in both the contralateral and ipsilateral cortex 6 h after the onset of ischemia. Stroke resulted in dynamic changes of SIRT1 protein and activity levels which varied among brain regions. Administration of nicotinamide (200 mg/kg, i.p.) up to 1 h after the onset of ischemia elevated brain NAD⁺ levels and reduced ischemic infarct size. Our findings demonstrate that the NAD⁺ bioenergetic state is critical in determining whether neurons live or die in excitotoxic and ischemic conditions, and suggest a potential therapeutic benefit in stroke of agents that preserve cellular NAD⁺ levels. Our data further suggest that, SIRT1 is linked to bioenergetic state and stress responses in neurons, and that under conditions of reduced cellular energy levels SIRT1 enzyme activity may consume sufficient NAD⁺ to nullify any cell survival-promoting effects of its deacetylase action on protein substrates.     

Exacerbation of Epilepsy by Astrocyte Alkalization and Gap Junction Uncoupling

Seizures invite seizures. At the initial stage of epilepsy, seizures intensify with each episode; however, the mechanisms underlying this exacerbation remain to be solved. Astrocytes have a strong control over neuronal excitability and the mode of information processing. This control is accomplished by adjusting the levels of various ions in the extracellular space. The network of astrocytes connected via gap junctions allows a wider or more confined distribution of these ions depending on the open probability of the gap junctions. K⁺ clearance relies on the K⁺ uptake by astrocytes and the subsequent diffusion of K⁺ through the astrocyte network. When astrocytes become uncoupled, K⁺ clearance becomes hindered. Accumulation of extracellular K⁺ leads to hyperexcitability of neurons. Here, using acute hippocampal slices from mice, we uncovered that brief periods of epileptiform activity result in gap junction uncoupling. In slices that experienced short-term epileptiform activity, extracellular K⁺ transients in response to glutamate became prolonged. Na⁺ imaging with a fluorescent indicator indicated that intercellular diffusion of small cations in the astrocytic syncytium via gap junctions became rapidly restricted after epileptiform activity. Using a transgenic mouse with astrocyte-specific expression of a pH sensor (Lck-E²GFP), we confirmed that astrocytes react to epileptiform activity with intracellular alkalization. Application of Na⁺/HCO₃^– cotransporter blocker led to the suppression of intracellular alkalization of astrocytes and to the prevention of astrocyte uncoupling and hyperactivity intensification both in vitro and in vivo. Therefore, the inhibition of astrocyte alkalization could become a promising therapeutic strategy for countering epilepsy development.SIGNIFICANCE STATEMENT We aimed to understand the mechanisms underlying the plastic change of forebrain circuits associated with the intensification of epilepsy. Here, we demonstrate that first-time exposure to only brief periods of epileptiform activity results in acute disturbance of the intercellular astrocyte network formed by gap junctions in hippocampal tissue slices from mice. Moreover, rapid clearance of K⁺ from the extracellular space was impaired. Epileptiform activity activated inward Na⁺/HCO₃^– cotransport in astrocytes by cell depolarization, resulting in their alkalization. Our data suggest that alkaline pH shifts in astrocytes lead to gap junction uncoupling, hampering K⁺ clearance, and thereby to exacerbation of epilepsy. Pharmacological intervention could become a promising new strategy to dampen neuronal hyperexcitability and epileptogenesis.     

Myelin glycosphingolipid immunoreactivity and CSF levels in multiple sclerosis

Haghighi S, Lekman A, Nilsson S, Blomqvist M, Andersen O. Myelin glycosphingolipid immunoreactivity and CSF levels in multiple sclerosis.
Acta Neurol Scand: 2012: 125: 64–70.
© 2011 John Wiley & Sons A/S. Objectives – Patients with multiple sclerosis were reported to harbour antibodies not only against proteins and glycoproteins but also against glycolipids, including sulfatide and galactosylceramide (GalCer), the two major glycosphingolipids of myelin. However, previous results were inconsistent concerning glycosphingolipid levels, antibody type, dominance of serum or Cerebrospinal fluid compartments and relationship to the multiple sclerosis (MS) course. Results – We hereby report that the cerebrospinal fluid levels of sulfatide were increased in patients with MS (n = 46) compared with controls (n = 50, P < 0.001). In addition, patients had higher serum IgM anti‐glycosphingolipid titres than controls (P = 0.03 for sulfatide, <0.001 for GalCer), while the anti‐glycosphingolipid IgM antibodies in the cerebrospinal fluid were essentially normal. However, in seven of 46 patients cerebrospinal fluid IgG antibodies against GalCer (P = 0.004) could be detected, which was not found in any of the control individuals, and this finding might mirror the occurrence of more specific B‐cell clones behind the blood–brain barrier. Conclusions – The IgM immunoreactivity in serum did not show any relationship to the type of course or severity of MS, arguing against a phenomenon secondary to myelin damage. Thus, the IgM antibody findings are compatible with an early antigen challenge or autoimmunity associated with natural antibodies.     

Reduced Cd4+Cd25+ T cells in patients with idiopathic thrombocytopenic purpura

Immunoregulatory CD4(+)CD25(+) T cells play an important role in the induction and maintenance of peripheral self-tolerance. These professional regulatory cells prevent the activation and proliferation of potentially autoreactive T cells that have escaped thymic deletion. Therefore, CD4(+)CD25(+) T cells are believed to possibly play an important role in pathogenic autoimmune diseases. We measured the count of CD4(+)CD25(+) T cells in 44 patients with idiopathic thrombocytopenic purpura (ITP), and the number of CD4(+)CD25(+) T cells and clinical features were then analyzed. By using a flow cytometric analysis, the number of CD4(+)CD25(+) T cells in the patients with ITP showed a very wide distribution in comparison to healthy volunteers. The number of CD4(+)CD25(+) T cells was significantly lower in the ITP patients in the severe phase, and in patients positive for anti-glycoprotein IIb-IIIa antibody. However, the number of those cells increased in the patients at the complete remission phase, especially after a splenectomy. The Foxp3 mRNA levels of peripheral blood mononuclear cells (PBMC) of ITP patients were higher with an improved platelet count than in those with a low platelet count. In addition, the Foxp3 mRNA levels closely correlated with the number of CD4(+)CD25(+) cells. These mechanisms remain to be fully elucidated, however, the count of CD4(+)CD25(+) T cells is considered to possibly be related to the severity of ITP.     

Circulating CD4+CD8+ cells in myasthenia gravis: supplementary immunological parameter for long-term prognosis

Summary Twenty patients with myasthenia gravis (MG) were studied prospectively for up to 5 years after thymectomy, in order to clarify the relationships between disease severity, anti-acetylcholine receptor antibody (anti-AChR) titres, proportions of circulating CD4⁺CD8⁺ cells (CD4⁺CD8⁺ cell level) and major lymphocyte subsets. The CD4⁺CD8⁺ cell levels were closely related to the clinical change within 1 year after surgery in 8 patients who showed a preoperative elevation in the cell levels. This group of patients consisted of six thymomatous and two non-thymomatous patients; the latter were both negative for anti-AChR. The anti-AChR titres generally changed in parallel with the clinical state in 9 of the 16 patients who were followed up for more than a year after thymectomy, and the CD4⁺CD8⁺ cell levels were useful in predicting the clinical course in 6 of the above 9 patients and 3 other patients, including antibody-negative cases. The present study suggests that the CD4⁺CD8⁺ cell levels may serve as an indicator for long-term prognosis of MG.     

首发抑郁症患者外周血CD4+CD25+CD127-调节性T细胞的研究

目的 探讨首发抑郁症患者治疗前后外周血中CD4⁺CD25⁺CD127^-占CD4⁺的比例及Treg细胞与抗抑郁治疗的相关性。方法 纳入在大庆市第三医院住院治疗的首发抑郁症患者共20例,均符合《精神障碍诊断与统计手册（第5版）》（DSM-5）关于抑郁障碍的诊断标准,汉密尔顿抑郁量表17项版（HAMD-17）总评分>20分;同期纳入在大庆市第三医院体检中心的健康成人作为对照组,共20例。对抑郁症患者治疗前及治疗12周后分别进行HAMD-17评定。对抑郁症患者治疗前、治疗12周后及健康对照组分别采取其外周血,利用流式细胞术（FCM）测定外周血CD4⁺CD25⁺CD127^-占淋巴细胞的百分比及CD4⁺CD25⁺CD127^-占CD4⁺T细胞的百分比,并作对照分析。结果 在CD4⁺CD25⁺CD127^-/CD4⁺的水平上,抑郁症患者治疗前、治疗后均高于健康对照组,差异均有统计学意义（P均<0.01）;抑郁症患者HAMD-17评分及血清CD4⁺CD25⁺CD127^-/CD4⁺的水平均下降,差异均有统计学意义（P均<0.05）,且抑郁症显效组CD4⁺CD25⁺CD127^-/CD4⁺的变化率与HAMD-17评分减分率呈正相关（r=0.716,P<0.05）。结论 抑郁症患者经SSRIs类药物治疗后,外周血CD4⁺CD25⁺CD127^-/CD4⁺水平的降低预示抗抑郁疗效较好,有效的抗抑郁治疗可能与调节T细胞有一定的相关性。     

Role of opioidergic and monoaminergic neurotransmission in the GnRH release mechanism of EBP-primed OVX rats

We examined the effect of intracerebroventricular (i.c.v.) administration of μ-opioid agonist, morphine, and its antagonist naloxone followed by morphine on the activities of monoamine-metabolizing enzymes, namely tyrosine hydroxylase (TH) and monoamine oxidase (MAO) along with adenosinetriphosphatase (Na⁺, K⁺ -ATPase), the enzyme responsible for the maintenance of ionic gradients across the membrane, in seven discrete regions of brain from estrogen- and progesterone-primed ovariectomized rats. TH activity decreased after morphine treatment in some areas such as the median eminence-arcuate region (ME-ARC), the amygdala, and the thalamus, showing statistically significant change. MAO activity increased in all the areas studied, but more appreciable change was observed in medial preoptic area (mPOA), the ME-ARC region, and the cortex. Pronounced increase in Na⁺, K⁺ -ATPase enzyme activity was observed after the drug treatment. Naloxone given prior to morphine injection resulted in recovery of the enzyme activities in most of the areas studied. Our study may provide insights into the precise opioidergic modulation of gonadotropin releasing hormone (GnRH) release mechanisms through the involvement of monoaminergic system, elucidating the basis of various neuronal dysfunctions and their management in opioid addicts.     

多发性硬化与髓鞘抗体及髓鞘碱性蛋白

探讨多发性硬化的免疫发病机制。方法采用ELISA方法测定多发性硬化患者活动期血清（28例）和脑脊液（18例）的GM1抗体、脑磷脂抗体和髓鞘碱性蛋白。结果多发性硬化患者血清GM1抗体阳性率为36％,脑磷脂抗体为43％;脑脊液GM1抗体为11％,脑磷脂抗体为18％,与对照组比较差异均有显著性;血清和脑脊液的髓鞘碱性蛋白增高亦有意义。结论体液免疫参与了多发性硬化的发病过程。可能的机制是,针对自身组织的髓鞘蛋白、髓鞘脂质等自身免疫系统被激活,产生一系列病理改变和临床症状。     

CD8 high CD11b low T cells (T suppressor-effectors) in multiple sclerosis cerebrospinal fluid are increased during high dose corticosteroid treatment

Using simultaneous dual direct immunofluorescence the effect of high dose intravenous methylprednisolone on the expression of T lymphocyte differentiation antigens in paired cerebrospinal fluid and peripheral blood samples of nine clinically active patients with multiple sclerosis was studied. Corticosteroid treatment was associated with a clinical improvement in eight out of the nine patients. In cerebrospinal fluid of all patients the treatment was associated with a decrease of CD3+, CD4+ and CD8+ T cells, and of intra-central nervous system IgG synthesis. CD8+ high CD11b+ low suppressor-effector T cells behaved differently in the eight patients who improved with treatment, where they significantly increased, and in the patient without clinical response, where they were almost unchanged. Similar phenotypic changes were found in peripheral blood, and all changes returned towards baseline after treatment. The lower sensitivity to corticosteroids of CD8+ high CD11b+ low T cells could change the balance between immunoregulatory T subsets. In this study the increased availability of a subpopulation mainly composed of T cells with a suppressor-effector function was associated with a clinical response to treatment.     

Dependence of axolemmal differentiation on contact with glial cells in chronically demyelinated lesions of cat spinal cord

Chronically demyelinated lesions of cat dorsal columns were created by focal injection of the glial toxin ethidium bromide. Freeze-fracture studies show that the center of the lesion, which is devoid of glial cells and processes, contains axons having neither node-like nor paranodal-type membrane specializations. Near the margin of the lesion, however, where axons are in contact with glial cells, the axolemma sometimes displays focal accumulations of E- and P-face particles resembling those at nodes of Ranvier. In cases where the adjacent cell could be identified, it had the characteristics of an astrocyte. Linear indentations of the axolemma displaying a paracrystalline pattern like that of the paranodal axolemma also occur in the marginal region. Here, the adjacent cell had the characteristics of an oligodendrocyte. These specializations may be closely associated with each other or spatially separate. Normal nodal and paranodal specializations were absent throughout the lesion at all time periods examined. These findings support the view that both the formation and the maintenance of nodal and paranodal axon membrane specializations require contact with glial cells.     

Astrogliopathy and oligodendrogliopathy are early events in CNS demyelination

We examined the phenotypic composition of cells and the underlying mechanisms of demyelination following injection of lipopolysaccharide (LPS) into the corpus callosum of rats. Terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay showed fragmented DNA, which co‐localized with oligodendrocytes in areas of demyelination following intracerebral injection with LPS. Immunostaining showed the presence of caspase 3 in cells which expressed the oligodendrocyte markers, suggesting activation of the apoptotic pathway. Commensurate reduction in glial fibrillary acid protein (GFAP)+/ gap junction protein connexin43+ (Cx43) cells, was also seen in the corpus callosum prior to histochemical evidence of demyelination. Expression of mRNA for proinflammatory cytokines was maximal 3 day postinjection, at a time when the numbers of TUNEL positive cells in the corpus callosum were declining and the total number of CD68+ cells peaked at day 14 postinjection. Our studies suggest that death of oligodendrocytes is an early event in LPS model of demyelination. We believe that the innate immune model of oligodendrocyte death will be useful in the development of neuroprotective agents capable of rescuing oligodendrocytes from apoptosis. GLIA 2013;61:1261–1273     

Effect of noradrenaline and vanadium on Na+K+-activated ATPase in rat cerebral cortex synaptosomal preparation

Summary The effect of l-noradrenaline and vanadate on the activity of Na⁺K⁺-activated ATPase was studied on synaptosomal brain cortex preparation. Using neutron activation analysis it was found that the rat cerebral cortex synaptosomal preparation contains 0.16M. vanadium. The concentration of vanadium needed to reduce enzyme activity by 50% proved to be 2×10^–6 M. Evidence has been provided that the increase by noradrenaline of enzyme activity in synaptosomal preparation depends on the presence of an inhibitory contaminant in commercial ATP preparations. In homogenate, however, noradrenaline was able to enhance enzyme activity even when vanadium-free ATP was used. This fact indicates that noradrenaline removes the inhibitory effect of cytoplasmic factor thereby stimulating enzyme activity.