PKR在阿尔茨海默

发布时间：2018-07-07 14:44

本文选题：阿尔茨海默病 + 轻度认知功能障碍　；参考：《河北医科大学》2012年硕士论文

【摘要】：阿尔茨海默病（Alzheimer’s disease，AD）是发生于老年和老年前期、以进行性认知功能障碍和行为损害为特征的中枢神经系统退行性病变，是老年期痴呆的最常见类型，主要表现为进行性全面认知功能损害。轻度认知功能障碍（Mild cognitive impairment，MCI）被认为是AD的临床前期，指记忆力受损但尚未达到痴呆的程度。我国60岁以上老年人口有1.2亿，痴呆患病率为3~8%，其中60%以上为阿尔茨海默病，以此比例，在我国估计有400~500万AD患者。帕金森病（Parkinson disease，PD），又名震颤麻痹（shaking palsy，paralysis agitans）是一种常见于中老年的神经系统变性疾病，于1817年由英国医生James Parkinson首先系统的进行描述故而得名。PD的发病年龄在40~70岁之间，其中，，50~60岁为发病高峰。我国55岁~65岁人群患病率为约1%，随着年龄增高而升高，男性稍高于女性。随着人口老龄化进程，阿尔茨海默病和帕金森病的发病率均逐年上升。尤其AD已成为继肿瘤、心血管疾病、脑血管疾病之后导致死亡的第四位疾病，二者均严重影响患者的生活质量，给家庭、政府和社会带来沉重的生活和经济负担。国内外在AD领域多为动物实验或尸检后研究神经元的受损情况，主要探讨AD的发病与细胞凋亡、细胞周期失调等机制的内在联系。然而，早期诊断AD，发现MCI患者是制定治疗策略、控制疾病进程的基础。近期研究表明，在AD中细胞凋亡、细胞周期调控的失调不仅局限于神经元，而且体现在外周血淋巴细胞和成纤维细胞，淋巴细胞为研究细胞周期相关事件在AD发病机制中的作用和寻找可干预的靶点提供了方便有用的模型。外周血采集方便，外周血淋巴细胞（peripheral blood lymphocytes，PBLs）是血液循环中的淋巴细胞。主要由T细胞（约占70%~80%）和B细胞（约占20%~30%）组成。因此，深入研究可能为早期诊断AD提供方便有效的外周标记物和药物干预的靶点。如果能从外周血中获得简便、有效的标志物将对AD早期诊断及治疗产生重要意义，但至今尚无这样的标志物为临床所应用。双链RNA-依赖的蛋白激酶（the double stranded RNA-dependentprotein kinase，PKR），是一种丝/苏氨酸蛋白激酶，它是真核生物起始因子2α（eIF-2α）的特异蛋白激酶，双链RNA可赋予或抑制其活性。活化的PKR可形成同源二聚体，在多个丝/苏氨酸残基上实现自身磷酸化，然后催化其底物eIF-2α磷酸化，从而减少或抑制蛋白质的合成和翻译，在信号转导、应激、细胞生长、分化和凋亡调控中起重要作用。PKR还可激活与炎症、凋亡密切相关的NF-κB、P53等从而诱发炎症反应与肿瘤。几乎所有细胞型中都有PKR基础水平的表达，用干扰素诱导可以使其表达增高5~10倍。目前，PKR被认为是阿尔茨海默病调节的关键靶点，因此，研究其是否可作为与认知功能减退相关的外周血生物学标记具有可行性和必然性。本课题以临床患者为研究对象，对AD患者的外周血淋巴细胞中PKR的蛋白水平进行研究，有助于临床早期诊断和治疗。目的：1研究淋巴细胞中相关激酶PKR、P-PKR的表达情况，为筛查AD的可干预靶点提供细胞模型。 2在外周血淋巴细胞中研究细胞凋亡和细胞周期调控的相关激酶PKR、P-PKR的表达，寻找早期诊断AD的特异性外周标记物。 3同时，对年龄相当的正常人、轻度认知功能障碍的患者以及同为神经变性病的帕金森病患者外周血淋巴细胞中PKR、P-PKR水平进行检测，从而明确这一指标的敏感性和特异性。方法：1根据诊断标准和排除标准筛选病人，收集2010年9月至2011年10月河北医科大学第二医院神经内科门诊的AD患者20例、MCI患者20例、PD患者20例、正常对照组20例，征得患者同意，利用简易精神状态量表（MMSE）、临床痴呆量表（CDR）等综合评价认知障碍的程度并记录患者的个人信息。 2抽取患者新鲜静脉血置于抗凝管中上下颠倒几次，用人淋巴细胞分离液处理后经离心洗涤提取外周血淋巴细胞。 3从外周血淋巴细胞中提取总蛋白，采用Western Blotting技术，分别检测其中PKR、P-PKR的蛋白表达水平。 4统计学处理。采用SPSS17.0统计软件包进行处理。结果：1AD患者外周血淋巴细胞中PKR、P-PKR水平较MCI组、PD组升高，较正常对照组显著升高。 2MCI组、PD组外周血淋巴细胞中PKR、P-PKR水平相当，较正常对照组升高，但升高幅度不明显。 3外周血淋巴细胞中PKR、P-PKR水平与各组的MMSE评分、CDR评分呈负相关，与患者年龄和病程未见明显相关。结论：阿尔茨海默病早期往往无征兆，诊断困难。PKR、P-PKR在阿尔茨海默病患者、轻度认知功能障碍患者、帕金森患者、正常对照组外周血淋巴细胞中均有表达，只是表达量有所不同，可以与其他标志物一起联合作为AD诊断的外周血标志物。
[Abstract]:Alzheimer 's disease (AD), which is the most common type of senile dementia, is the most common type of senile dementia, which is characterized by cognitive impairment and behavioral impairment in the elderly and prophase. It is mainly manifested in progressive cognitive impairment. Mild cognitive dysfunction (Mild cognitive impa). Irment, MCI) is considered to be the preclinical of AD, which refers to the impairment of memory but has not reached the level of dementia. The population over 60 years old in China is 120 million, the prevalence rate of dementia is 3~8%, and more than 60% of them are Alzheimer's disease. In this proportion, there are an estimated 400~500 million AD in our country.
Parkinson's disease (Parkinson disease, PD), also known as shaking palsy (shaking palsy, paralysis agitans) is a kind of neurodegenerative disease common in the middle and old age. In 1817, the British doctor James Parkinson first described the onset age of.PD between the 40~70 years of age, among which the 50~60 year was the peak of the onset. China was 55 years old. The prevalence rate of the 65 year old group was about 1%, which was higher with age and slightly higher than that of the female.
With the aging process of the population, the incidence of Alzheimer's disease and Parkinson's disease has increased year by year. Especially, AD has become the fourth disease that leads to death after tumor, cardiovascular disease and cerebrovascular disease. The two all seriously affect the quality of life of the patients and bring heavy living and economic burden to the family, the government and the society.
The AD field at home and abroad is mostly about the damage of neurons after animal experiments or postmortem examination. It mainly discusses the internal relationship between the pathogenesis of AD and the mechanism of cell apoptosis and cell cycle disorders. However, early diagnosis of AD and the discovery of MCI patients are the basis for formulating therapeutic strategies and controlling the process of disease. Recent studies have shown that apoptosis and cell cycle in AD The dysregulation of phase regulation is not only limited to neurons, but also in peripheral blood lymphocytes and fibroblasts. Lymphocytes provide a convenient and useful model to study the role of cell cycle related events in the pathogenesis of AD and to find interferable targets.
Peripheral blood collection is convenient and peripheral blood lymphocytes (peripheral blood lymphocytes, PBLs) are lymphocytes in the blood circulation. It is mainly composed of T cells (about 70%~80%) and B cells (approximately 20%~30%). Therefore, in-depth study may provide a convenient and effective target for peripheral markers and drug intervention for early diagnosis of AD. If it can be from peripheral blood A simple and effective marker will be important for early diagnosis and treatment of AD. However, no such marker has been applied clinically.
Double stranded RNA- dependent protein kinase (the double stranded RNA-dependentprotein kinase, PKR), a kind of silk / threonine protein kinase, is a specific protein kinase of the eukaryotic initiation factor 2 alpha (eIF-2 a). Double stranded RNA can endow or inhibit its activity. Activated PKR can form homologous two polymer and can be realized on multiple silk / threonine residues. Body phosphorylation, then catalyzes the phosphorylation of its substrate eIF-2 a, thereby reducing or inhibiting the synthesis and translation of protein, and plays an important role in signal transduction, stress, cell growth, differentiation and apoptosis..PKR also activates NF- kappa B, which is closely related to apoptosis, and P53 induces inflammatory reactions and tumors. The expression of basal level of PKR can be increased by 5~10 times by interferon induction.
At present, PKR is considered to be the key target of Alzheimer's disease. Therefore, it is feasible and necessary to study whether it can be used as a biomarker of peripheral blood related to cognitive impairment.
This study is based on clinical patients. The study of PKR protein level in peripheral blood lymphocytes of AD patients is helpful for early diagnosis and treatment.
Objective: 1 to study the expression of PKR and P-PKR in lymphocytes, and provide a cell model for screening AD targets.
2 in peripheral blood lymphocytes, we studied the expression of PKR and P-PKR related to apoptosis and cell cycle regulation, looking for specific peripheral markers for early diagnosis of AD.
3 at the same time, PKR and P-PKR levels in peripheral blood lymphocytes of patients with normal age, mild cognitive impairment and the peripheral blood lymphocytes of Parkinson's disease with neurodegenerative disease were detected to determine the sensitivity and specificity of this index.
Methods: 1 according to the diagnostic criteria and exclusion criteria, 1 AD patients, 20 MCI patients, 20 PD patients and 20 normal controls were collected from September 2010 to October 2011 in the Department of Neurology in the Department of Neurology, Hebei Medical University. A comprehensive evaluation of the simple mental state scale (MMSE) and the Clinical Dementia Scale (CDR) was used. The degree of cognitive impairment was recorded and personal information was recorded.
2 the fresh venous blood of the patients was taken up and down several times in the anticoagulant tube. After treatment with human lymphocyte separation fluid, the peripheral blood lymphocytes were extracted by centrifugation.
3 the total protein was extracted from peripheral blood lymphocytes, and the protein expression level of PKR and P-PKR was detected by Western Blotting technique.
4 statistical processing. Use SPSS17.0 statistical software package for processing.
Results: the levels of PKR and P-PKR in peripheral blood lymphocytes of 1AD patients were higher than those in MCI group and PD group, which were significantly higher than those in normal control group.
In group 2MCI, the levels of PKR and P-PKR in peripheral blood lymphocytes of group PD were similar, higher than those of normal control group, but the amplitude of increase was not obvious.
3 the level of PKR and P-PKR in peripheral blood lymphocytes was negatively correlated with MMSE score and CDR score in each group, but no correlation was found between age and duration of disease.
Conclusion: Alzheimer's disease is often without signs and difficult to diagnose.PKR. P-PKR is expressed in the peripheral blood lymphocytes of Alzheimer's disease patients, mild cognitive impairment patients, Parkinson patients and normal control group, but the expression amount is different, which can be combined with other markers as the peripheral blood markers for the diagnosis of AD.
【学位授予单位】：河北医科大学
【学位级别】：硕士
【学位授予年份】：2012
【分类号】：R749.1

【参考文献】