小胶质细胞钾通道的表达与功能

小胶质细胞作为中枢神经系统的免疫细胞在阿尔采末病的慢性炎症过程中起关键作用。在小胶质细胞中有多种钾通道亚型的表达 ,钾通道可能是小胶质细胞对微环境变化作出反应的重要途径 ,钾通道的变化是小胶质细胞是否处于激活状态的重要标志 ,钾通道可能在如维持膜电位、细胞增生、分化等小胶质细胞的生理及病理过程中起关键作用     

炎性细胞因子与阿尔采末病

阿尔采末病 (AD)是一个复杂的病理生理过程 ,脑特异性炎症反应在其发病中起重要作用 ,有多种炎症细胞因子的参与 ,如IL 1、IL 6、TNF α和TGF β等。这些细胞因子在AD患者的脑中表达都明显地增加 ,可以激活小胶质细胞(MC)和星形细胞 (AC) ,活化的MC和AC又可引起炎症细胞因子产生 ,它们共同参与脑局部炎症过程 ,与神经纤维缠结和老年斑的形成密切相关。     

阿尔采末病的免疫治疗

综述阿尔采末病的免疫治疗,包括主动免疫治疗和被动免疫治疗;免疫治疗的疗效、不良反应,分析不良反应发生的原因及对策。     

Aβ寡聚体与阿尔采末病及其靶点药物研究进展

Aβ在阿尔采末病(AD)中起着重要的作用,寡聚化的Aβ分子被认为是AD发病的原发性因子,能够通过不同的机制发挥神经毒性作用,引发记忆损伤和神经元丢失,以Aβ为作用靶点的药物开发和应用也已初露端倪。该文对Aβ寡聚体在AD中的毒性作用和以Aβ为作用靶点的药物开发现状作一综述。     

阿尔采末病Aβ多肽基因的高效表达及纯化研究

目的　通过对Aβ多肽基因进行重组克隆 ,构建质粒和高效表达的菌株 ,并研究表达产物快速高效的纯化回收方法。方法　采用IMPACT TWIN表达系统构建Intein Aβ重组基因表达质粒 ,将该质粒转化至BL2 1(DE3) ,筛选高效表达菌株 ;表达产物经ChitinBeads亲和层析柱分离纯化 ;SDS PAGE电泳 ,毛细管区带电泳及免疫印迹法等鉴定。结果　重组的Intein Aβ基因在BL2 1中获得高效表达 ,筛选出稳定高效表达的BL2 1(DE3)细胞株 ;融合蛋白表达量可达全菌蛋白的 6 0 % ;表达产物经ChitinBeads亲和层析纯化后 ,其纯度可达 98%以上 ,并具有与Aβ多肽相同的分子量及免疫学活性。结论　Aβ多肽基因在IMPACT TWIN系统中可获得高效表达 ,利用ChitinBeads亲和层析方法可将表达的Aβ多肽进行快速、简便、无酶化的高效分离纯化。     

Tau蛋白与阿尔采末病

阿尔采末病是老年人痴呆最主要的原因 ,老年斑和神经元纤维缠结 (NFT)是其特征的病理性损伤。Tau蛋白是一种多功能的微管相关蛋白 ,能稳定微管 ,促进微管的装配。异常过磷酸化的Tau蛋白构成NFT的核心 ,Tau蛋白磷酸化程度是体内多种蛋白激酶 (如GSK 3、cdk5和MAPK)引起的磷酸化和蛋白磷酸酶 (如PP1、PP2 )脱磷酸化两种作用平衡的结果。Aβ产量的增加或改变可能是AD发病过程的启动环节 ,Tau蛋白功能异常改变可能是神经元功能障碍和死亡的必要环节 ,因此搞清正常或疾病状态下Tau蛋白的代谢和功能对于理解AD和发展针对性治疗是非常有意义的。     

晚期糖基化终产物受体与β-淀粉样蛋白的相互作用促进阿尔采末病的发展

晚期糖基化终产物受体(the receptor for advanced gly-cation end products,RAGE)属于免疫球蛋白家族。在中枢神经系统,RAGE主要在神经元、小胶质细胞及血管内皮细胞上表达。阿尔采末病(Alzheimers disease,AD)人脑中RAGE的表达可被β淀粉样蛋白(β-amyloid protein,Aβ)上调,上调的RAGE进一步促进了AD的发展。神经元、小胶质细胞和血管内皮细胞膜上RAGE和Aβ结合,引起神经元毒性、持久性的炎症反应、血管功能紊乱。对RAGE-Aβ作用机制的深入理解,可为AD的临床治疗提供理论基础。     

突轴核蛋白与阿尔采末病

突轴核蛋白 (α synuclein)是一种存在于突触前膜的蛋白 ,具有调节突触可塑性等正常生理功能。但其大量的积聚和变异将引起神经细胞的损伤 ,以致引起许多神经退行性疾病。在此过程中 ,α synuclein聚集和与其他分子相互作用的性质可能是关键因素。研究发现α synuclein是阿尔采末病人的老年斑块中非Aβ蛋白组分的前体 ,表明α synuclein的异常可能与阿尔采末病的病理过程有密切的关系。该文就其近年的研究进展做一综述。     

小胶质细胞极化在帕金森病中的作用

帕金森病(PD)是一种高发于中高年人群的神经退行性疾病。近年来,小胶质细胞介导的神经炎症在PD的发病过程中受到了广泛的关注。越来越多的证据表明,炎症微环境会极大地影响小胶质细胞的表型变化,不同极化类型的小胶质细胞可分泌不同作用的炎症因子,介导神经炎症,与PD的发病过程密切相关,但目前其相关机制尚不明确。目前研究认为,调节具有神经毒性的M1型小胶质细胞和产生神经保护作用的M2型小胶质细胞之间的平衡对PD中多巴胺能神经元的损伤起到重要的神经保护作用。本文就小胶质细胞极化在PD发病过程中的作用及其关机制进行综述,为靶向调控小胶质细胞极化治疗PD提供了新的思路并奠定相关基础。     

阿尔采末病非人灵长类动物模型

阿尔采末病(AD)是一种以进行性认知障碍和记忆力损害为主的中枢神经系统退行性疾病。非人灵长类动物(nonhumanprimate,NHP)模型较啮齿类动物模型更好地模拟了AD的病理变化,其神经生物学特性与人类非常相似,是研究AD等疾病最理想的动物模型,对筛选治疗老年痴呆药也起着至关重要的作用。恒河猴是目前应用最广泛的非人灵长类实验动物,另外松鼠猴、小猿、短尾猿、猩猩、黑猩猩和狐猴也是AD研究的理想实验动物。本文通过非人灵长类动物模型的胆碱能系统、β淀粉样肽沉积、载脂蛋白E、神经元纤维缠结和tau蛋白等方面的变化,对近年来NHP的自发性、诱发性及自身免疫性痴呆模型的发展分别进行阐述。     

Nicotinic receptors and Alzheimer's disease

SUMMARY

Nicotinic receptors (NRs) belong to the group of polymeric receptors of the cell membrane and are key elements of cholinergic transmission. Numerous subtypes of NRs exist, with the α4β2 and α7 types being encountered most frequently. Deficiencies in NRs seem to play a role in Alzheimer's disease, which is characterised by accumulation of senile plaques, mainly composed of β-amyloid peptide (βA). Although the aetiology of this disease is unknown, different pathogenesis hypotheses implicating α7 NRs have been proposed, with the receptors exerting a direct or indirect action on the mechanism of βA toxicity. Allosteric modulators of NRs, such as the cholinesterase inhibitor galantamine, that facilitate the action of acetylcholine on these receptors may provide therapeutic benefits in the areas of cognition, attention and antineurodegenerative activity.     

秀丽隐杆线虫模型在阿尔茨海默病研究中的应用

阿尔茨海默病(Alzheimer s disease,AD)是一种与衰老相关的神经退行性疾病,以Aβ沉积和Tau蛋白过度磷酸化为主要病理特征。秀丽隐杆线虫以其神经系统结构简单、遗传信息清晰等优势而作为一种AD研究的模式生物,尤其是人源Aβ1-42和Tau转基因线虫(CL2006/P301L)已被广泛应用。本文简述秀丽隐杆线虫及其AD模型,总结近几年应用模型线虫研究AD病理机制的文献,为进一步筛选治疗AD的药物提供可靠的线索和思路。     

Depression and Alzheimer's disease: Neurobiological links and common pharmacological targets

Depression is one of the most prevalent and life-threatening forms of mental illnesses, whereas Alzheimer's disease is a neurodegenerative disorder that affects more than 37 million people worldwide. Recent evidence suggests a strong relationship between depression and Alzheimer's disease. A lifetime history of major depression has been considered as a risk factor for later development of Alzheimer's disease. The presence of depressive symptoms can affect the conversion of mild cognitive impairment into Alzheimer's disease. Neuritic plaques and neurofibrillary tangles, the two major hallmarks of Alzheimer's disease brain, are more pronounced in the brains of Alzheimer's disease patients with comorbid depression as compared with Alzheimer's disease patients without depression. On the other hand, neurodegenerative phenomena have been observed in different brain regions of patients with a history of depression. Recent evidence suggests that molecular mechanisms and cascades that underlie the pathogenesis of major depression, such as chronic inflammation and hyperactivation of hypothalamic-pituitary-adrenal (HPA) axis, are also involved in the pathogenesis of Alzheimer's disease. In particular, a specific impairment in the signaling of some neurotrophins such as transforming-growth-factor β1 (TGF-β1) and brain-derived neurotrophic factor (BDNF) has been observed both in depression and Alzheimer's disease. In the present review we will examine the evidence on the common molecular pathways between depression and Alzheimer's disease and we will discuss these pathways as new pharmacological targets for the treatment of both major depression and Alzheimer's disease.     

Alzheimer's disease and inflammation: a review of cellular and therapeutic mechanisms

1. Of the neurodegenerative diseases that cause dementia, Alzheimer's disease (AD) is the most common. Three major pathologies characterize the disease: senile plaques, neurofibrillary tangles and inflammation. We review the literature on events contributing to the inflammation and the treatments thought to target this pathology. 2. The senile plaques of AD consist primarily of complexes of the beta-amyloid protein. This protein is central to the pathogenesis of the disease. 3. Inflammatory microglia are consistently associated with senile plaques in AD, although the classic inflammatory response (immunoglobulin and leucocyte infiltration) is absent. beta-Amyloid fragments appear to mediate such inflammatory mechanisms by activating the complement pathway in a similar fashion to immunoglobulin. 4. Epidemiological studies have identified a reduced risk of AD in patients with arthritis and in leprosy patients treated with anti-inflammatory drugs. Longitudinal studies have shown that the consumption of anti-inflammatory medications reduces the risk of AD only in younger patients (< 75 years). 5. There is a considerable body of in vitro evidence indicating that the inflammatory response of microglial cells is reduced by non-steroidal anti-inflammatory drugs (NSAID). However, no published data are available concerning the effects of these medications on brain pathology in AD. 6. Cyclo-oxygenase 2 enzyme is constitutively expressed in neurons and is up-regulated in degenerative brain regions in AD. Non-steroidal anti-inflammatory drugs may reduce this expression. 7. Platelets are a source of beta-amyloid and increased platelet activation and increased circulating beta-amyloid have been identified in AD. Anti-platelet medication (including NSAID) would prevent such activation and its potentially harmful consequences. 8. Increased levels of luminal beta-amyloid permeabilizes the blood-brain barrier (BBB) and increases vasoconstriction of arterial vessels, paralleling the alterations observed with infection and inflammation. Cerebral amyloidosis is highly prevalent in AD, compromising the BBB and vasoactivity. Anti-inflammatory medications may alleviate these problems.     

The use of the hippocampal slice preparation in the study of Alzheimer's disease

In the present article we show how studying synaptic mechanisms in hippocampal slice preparations provides information that may be useful in, firstly, the understanding of the aetiology of Alzheimer's disease and, secondly, in the development of novel therapies for dementia. We use several examples, drawn from our own work: (i) The identification of the function of AMPA receptors and NMDA receptors in synaptic transmission and synaptic plasticity. (ii) The discovery of mechanisms that can regulate the activation of NMDA receptors. (iii) The use of transgenic models of Alzheimer's disease. (iv) The identification of a mechanism that can account for the cognitive enhancing effects of the NMDA receptor antagonist memantine. (v) The discovery of a role of glycogen synthase kinase-3beta (tau kinase) in synaptic plasticity.     

The effect of tacrine and lecithin in Alzheimer's disease

Tacrine, a cholinesterase inhibitor, has beneficial effects on cognition and global status in patients with Alzheimer's disease. These effects have been demonstrated in clinical trials by double-blind comparisons with placebo. Tacrine dosages have been studied in 5 protocols that used either enrichment or parallel designs.We have used a population pharmacodynamic model to describe the response to tacrine and placebo in the 3 trials that used the enrichment design. The time-course of the response and its relation to tacrine dosage obtained from the enrichment design analysis were used to define the parallel design.The effects of tacrine on cognition and global status was estimated separately from each trial. Analysis of the 2 trials using the parallel design confirmed the predictions from the enrichment design. By combining the data from all 5 trials it was possible to show that tacrine potency was similar in all studies, but that the placebo response was different in some. The effect of tacrine was linearly proportional to dosage from 40 to 160 mg per day.One of the enrichment design trials included a subgroup treated with lecithin, a choline precursor. The potency of lecithin was equivalent to about 40 mg per day of tacrine. Using the combined data from all 5 trials it was possible to distinguish a responder population, approximately one-third of all patients, with a 4-fold greater effect compared with poor responders.Tacrine has beneficial effects on cognitive status in patients with Alzheimer's disease. Lecithin has a small additional benefit independent of tacrine. The pharmacodynamic model predicts a 1.94 year delay in disease progression at a dose of 160 mg per day for patients who are similar to the responders in the 5 clinical trials.     

Scopolamine challenges in Alzheimer's disease

A challenge paradigm was designed to test the functional sensitivity to anticholinergic agents in Alzheimer's disease. Ten patients with dementia of the Alzheimer type were serially administered three different intravenous doses of the centrally active anticholinergic drug scopolamine and placebo. Testing was carried out in a placebo-controlled, double-blind fashion to measure cognitive, physiologic and behavioral changes. Alzheimer patients showed a marked, dose-related behavioral and cognitive sensitivity to temporary cholinergic blockade. Scopolamine testing may serve as an index of the status of central cholinergic functional integrity, and ultimately may prove useful as a diagnostic or staging test in the evaluation of the cholinergic system in dementia. Research is currently under way with elderly age-matched controls and populations with other neuropsychiatric disorders to explore this hypothesis further.