本文關(guān)鍵詞：阿爾茨海默病病因的基因表達(dá)譜數(shù)據(jù)分析　出處：《南方醫(yī)科大學(xué)》2015年碩士論文　論文類(lèi)型：學(xué)位論文

  更多相關(guān)文章： 阿爾茨海默病 基因表達(dá)譜 發(fā)病機(jī)制 生物信息 主成分分析 聚類(lèi)分析

【摘要】：阿爾茨海默病是一種常見(jiàn)的慢性、進(jìn)行性中樞神經(jīng)系統(tǒng)退行性疾病,其臨床主要表現(xiàn)為進(jìn)行性的記憶衰退和認(rèn)知功能的下降、行為異常和社交障礙,通常病情呈進(jìn)行性加重,病程緩慢不可逆。隨著社會(huì)人口的老齡化,阿爾茨海默病的發(fā)病率呈上升趨勢(shì)。據(jù)統(tǒng)計(jì)數(shù)據(jù)顯示,老年人阿爾茨海默病(Alzheimer's Disease, AD)的患病率僅次于心血管病和癌癥居第三位,全世界有近3600萬(wàn)人正在遭受著AD的折磨。目前阿爾茨海默病還是絕癥,沒(méi)有任何治療方法可以使患者痊愈。阿爾茨海默病給社會(huì)和家庭帶來(lái)沉重的負(fù)擔(dān),給患者本人也帶來(lái)精神上和身體上的極大痛苦。阿爾茨海默病可發(fā)生在成年人的任何年齡,發(fā)病率隨年齡的增長(zhǎng)而成指數(shù)型增長(zhǎng)。女性的發(fā)病率較男性高,農(nóng)村人發(fā)病率較城市人高,受教育程度高的人群發(fā)病率相對(duì)較低。AD的致病危險(xiǎn)因素還包括受教育程度低、頭部外傷、性激素水平降低、家族遺傳史、吸煙、抑郁癥狀、心理壓力、血管因素、體溫較低、社會(huì)活動(dòng)較少、輕度認(rèn)知損傷以及病毒感染等。阿爾茨海默病病灶一般先出現(xiàn)在大腦邊緣系統(tǒng)的海馬區(qū)、內(nèi)嗅皮層等部位,隨后蔓延到顳葉、扣帶回、頂葉、額葉等大腦皮層區(qū),一般波及不到枕葉、小腦、運(yùn)動(dòng)和感覺(jué)皮層區(qū)域。阿爾茨海默病人大腦的病理病變有：神經(jīng)炎性老年斑(senile plaques,SPs),神經(jīng)原纖維纏結(jié)(neurofibrillary tangles,NFTs),神經(jīng)細(xì)胞和突觸的消失,腦淀粉樣血管病以及顆�？张葑冃蔚�,整體表現(xiàn)為彌漫性大腦皮質(zhì)的萎縮和腦室的擴(kuò)大。阿爾茨海默病的發(fā)病機(jī)制仍然不清楚。目前有分子遺傳和基因?qū)W說(shuō)、炎癥學(xué)說(shuō)、自由基學(xué)說(shuō)、膽堿能學(xué)說(shuō)、金屬離子假說(shuō)、病毒學(xué)說(shuō)、氧化應(yīng)激學(xué)說(shuō)、雌激素水平降低學(xué)說(shuō)等。大多數(shù)研究猶如盲人摸象,分不清哪些機(jī)制是病因哪些是造成的結(jié)果。因此很多研究所和大學(xué)機(jī)構(gòu)也投入了相當(dāng)多的人力物力來(lái)研究AD的發(fā)病機(jī)制,但效果很不理想。目前需要從整體宏觀上來(lái)認(rèn)識(shí)這個(gè)疾病,而且不能受到各個(gè)機(jī)制的單獨(dú)片面影響。需要從基因表達(dá)上入手,以基因表達(dá)差異的客觀現(xiàn)象來(lái)了解和研究AD的發(fā)病機(jī)制、治療手段以及早期檢測(cè)方法。由于神經(jīng)細(xì)胞的復(fù)雜,而且取樣有限,從基因表達(dá)水平篩選出和年齡相關(guān)的基因,成為阿爾茨海默病分子發(fā)病機(jī)理研究的最佳途徑。近年發(fā)展起來(lái)的基因芯片技術(shù),顯示了其在功能相關(guān)差異基因篩選方面的優(yōu)越性,少量取樣就能獲得海量的基因表達(dá)數(shù)據(jù),這將增強(qiáng)對(duì)阿爾茨海默病了解,而且得到的數(shù)據(jù)更為客觀,具有較高的整體性。目前,由于高通量基因芯片技術(shù)的廣泛應(yīng)用,各個(gè)研究所和實(shí)驗(yàn)室產(chǎn)生出了大量的實(shí)驗(yàn)數(shù)據(jù),但是這些數(shù)據(jù)的信息只用到了小部分,全部信息往往沒(méi)有被完全挖掘出來(lái)。美國(guó)國(guó)立生物技術(shù)信息中心(National Center for Biotechnology Information, NCBI)建立的GEO (Gene Expression Omnibus)數(shù)據(jù)庫(kù)是當(dāng)前規(guī)模最大、收錄最全、免費(fèi)開(kāi)放的公共基因表達(dá)數(shù)據(jù)庫(kù),包含大量的、各種各樣的復(fù)雜生物數(shù)據(jù)。這些數(shù)據(jù)從表面上看起來(lái)是雜亂無(wú)章,無(wú)可下手,但是海量的生物學(xué)數(shù)據(jù)中必然蘊(yùn)含著重要的生物學(xué)規(guī)律,這些規(guī)律將是解釋阿爾茨海默病病因的關(guān)鍵。基因表達(dá)譜數(shù)據(jù)龐大復(fù)雜,變量數(shù)以萬(wàn)計(jì)。為此,通過(guò)使用Qlucore Omics Explorer (QOE) 3.0生物信息學(xué)軟件,把數(shù)據(jù)經(jīng)統(tǒng)計(jì)計(jì)算,快速轉(zhuǎn)換為3D可視化圖,再經(jīng)過(guò)主成分分析(Principle Component Analysis, PCA)和聚類(lèi)分析,識(shí)別出數(shù)據(jù)中隱藏的結(jié)構(gòu)和模式,以標(biāo)準(zhǔn)的統(tǒng)計(jì)學(xué)方法得到樣本與樣本之間、組與組之間以及數(shù)據(jù)集與數(shù)據(jù)集之間的差異與聯(lián)系。篩選出共同或差異的基因,再通過(guò)Database for Annotation, Visualization and Integrated Discovery (DAVID)6.7在線(xiàn)基因注釋系統(tǒng),對(duì)基因列表進(jìn)行Gene Ontology (G O)功能富集分析,從Cellular Component (CC),Biological Process (BP),Molecular Function (MF)三個(gè)方面對(duì)基因涉及的功能進(jìn)行注釋、富集、聚類(lèi)。得出AD患者生物學(xué)過(guò)程、細(xì)胞組成以及分子功能方面上的差異和變化。因此,本人根據(jù)目前現(xiàn)有的人類(lèi)阿爾茨海默病基因表達(dá)譜數(shù)據(jù)集,從整體的基因表達(dá)差異、隨年齡增長(zhǎng)的基因表達(dá)差異、各個(gè)腦區(qū)的基因表達(dá)差異、不同發(fā)病階段的基因表達(dá)差異、性別相關(guān)的基因表達(dá)差異入手,對(duì)阿爾茨海默病的發(fā)病機(jī)制進(jìn)行探究。首先,使用數(shù)據(jù)集GSE36980,通過(guò)兩組比較,篩選出阿爾茨海默病患者和正常人的大腦的差異基因196個(gè)。對(duì)差異基因進(jìn)行表達(dá)和功能的聚類(lèi)分析,結(jié)果分為42個(gè)注釋集群,涉及的GO主要有蛋白質(zhì)定位、離子轉(zhuǎn)運(yùn)、細(xì)胞信號(hào)、學(xué)習(xí)記憶、披網(wǎng)格蛋白小泡、突觸、細(xì)胞質(zhì)膜、細(xì)胞連接、線(xiàn)粒體、鈣離子綁定、離子通道、tau蛋白激酶以及脂肪酸轉(zhuǎn)運(yùn)等。這些差異功能都和阿爾茨海默病臨床表現(xiàn)以及病理有一定的聯(lián)系。這些結(jié)果證明并支持了阿爾茨海默病大腦內(nèi)神經(jīng)元的蛋白體破壞補(bǔ)償機(jī)制,神經(jīng)元突觸大量減少而且其功能受到嚴(yán)重影響,同時(shí)又發(fā)現(xiàn)了高爾基體在阿爾茨海默病患者的大腦中都會(huì)形成碎片的原因和相關(guān)差異基因。阿爾茨海默病的神經(jīng)元細(xì)胞膜遭到了破壞,線(xiàn)粒體功能的異常使細(xì)胞能量供應(yīng)受損,并產(chǎn)生過(guò)量的自由基。陰離子通道和金屬陽(yáng)離子通道異常,致使細(xì)胞信息傳遞和信號(hào)通路的錯(cuò)誤發(fā)生。阿爾茨海默病人的學(xué)習(xí)記憶相關(guān)基因及生物學(xué)進(jìn)程發(fā)生變化,造成了記憶和認(rèn)知功能的下降。細(xì)胞骨架及微管也發(fā)生異常并導(dǎo)致神經(jīng)元的立體空間結(jié)構(gòu)和連接遭到破壞,其中磷酸化過(guò)程也出現(xiàn)異常,這將使tau蛋白過(guò)度磷酸化,并形成神經(jīng)元纖維纏結(jié)。為了篩選出和年齡因素相關(guān)的阿爾茨海默病易感基因,本人同時(shí)使用GSE36980和GSE53890數(shù)據(jù)集,通過(guò)線(xiàn)性回歸和兩組比較結(jié)合,篩選出來(lái)20個(gè)在阿爾茨海默病和正常人中有差異又在年齡上有線(xiàn)性趨勢(shì)的基因。差異基因涉及的GO生物學(xué)過(guò)程主要有蛋白質(zhì)代謝、細(xì)胞周期、神經(jīng)代謝正調(diào)控、軸突、質(zhì)膜、突觸、細(xì)胞骨架、和金屬離子綁定。這些功能隨著年齡增長(zhǎng)而減弱是阿爾茨海默病發(fā)病率和年齡有正相關(guān)性的原因,這也說(shuō)明了正常人年齡的增加會(huì)導(dǎo)致大腦萎縮,大腦相關(guān)功能減弱,并出現(xiàn)類(lèi)阿爾茨海默的相關(guān)癥狀。不同大腦區(qū)域的阿爾茨海默病發(fā)病率也不一樣。此部分使用GSE36980和GSE9770這兩個(gè)數(shù)據(jù)集,通過(guò)兩組比較和多組比較,篩選出11個(gè)在各個(gè)腦區(qū)差異表達(dá)的阿爾茨海默病易感基因。這些基因的功能主要涉及細(xì)胞極性的建立或維護(hù)、離子綁定、質(zhì)膜功能、鈣離子綁定,這些功能都和信號(hào)傳導(dǎo)和信息傳遞功能有關(guān)。邊緣系統(tǒng)的這些功能較其他區(qū)域活性較高,這是邊緣系統(tǒng)易受疾病的影響重要原因,也是阿爾茨海默發(fā)病后先出現(xiàn)學(xué)習(xí)、情緒和記憶障礙的原因。其中有兩個(gè)基因CBLN4和LRRTM1也是年齡相關(guān)的阿爾茨海默差異表達(dá)基因。通過(guò)秩回歸分析GSE1297數(shù)據(jù)集,篩選出了隨病程加劇而變化的基因,該數(shù)據(jù)集是不同病程的海馬區(qū)神經(jīng)元的基因表達(dá)譜數(shù)據(jù)。結(jié)果中有65個(gè)基因被篩選出來(lái),其中32個(gè)隨疾病加重不斷上調(diào)表達(dá),33個(gè)基因隨疾病加重下調(diào)表達(dá)。其中上調(diào)的基因涉及的GO功能包括轉(zhuǎn)錄調(diào)節(jié)、質(zhì)膜組分等。下調(diào)的基因涉及GO功能有線(xiàn)粒體功能、蛋白質(zhì)定位和運(yùn)輸、核苷酸綁定等。因此,對(duì)于不同發(fā)病程度的AD患者,應(yīng)根據(jù)其生物學(xué)相關(guān)功能的改變采取個(gè)性化的治療方法以及精準(zhǔn)的藥物劑量。男性女性的大腦基因表達(dá)有一定的差異,為探究阿爾茨海默病女性發(fā)病率男性高的基因表達(dá)層面上原因,研究采用了GSE36980數(shù)據(jù)集,并選用數(shù)據(jù)集中的阿爾茨海默病組,在組內(nèi)進(jìn)行性別的兩組比較,在滿(mǎn)足統(tǒng)計(jì)學(xué)意義的前提下篩選出了26個(gè)男女大腦表達(dá)差異基因。這些基因涉及的GO生物學(xué)功能包含細(xì)胞骨架、離子傳遞、蛋白質(zhì)運(yùn)輸與定位、核苷綁定以及膜功能等。這些功能的相關(guān)基因表達(dá)女性比男性較低,是女性較男性易感阿爾茨海默的原因之一。其中差異基因列表中還包含CBLN4基因,說(shuō)明此基因在阿爾茨海默病的發(fā)病機(jī)制中起著非常重要的作用。以上所有分析是以基因表達(dá)水平上對(duì)阿爾茨海默病進(jìn)行研究,從整體水平上的流行病學(xué)統(tǒng)計(jì)結(jié)果和病理現(xiàn)象找出差異基因,并分析差異變化的生物學(xué)功能。把宏觀和微觀聯(lián)系起來(lái),為阿爾茨海默病的預(yù)防、診斷、研究和治療提供客觀的理論支持。
[Abstract]:Alzheimer's disease is a common chronic progressive neurodegenerative disease of the central nervous system. Its main clinical manifestations are progressive memory impairment and cognitive decline, behavioral abnormalities and social barriers. Usually, the disease is progressively aggravated, and the course of disease is slow and irreversible. With the aging of the population, the incidence of Alzheimer's disease is on the rise. According to statistics, the prevalence of Alzheimer's Disease (AD) is third only in the elderly, ranking the top 36 million in cardiovascular disease and cancer. Nearly 36 million people in the world are suffering from AD. At present, Alzheimer's disease is still a disease, and there is no cure for the patient. Alzheimer's disease brings a heavy burden to the society and the family, and brings great mental and physical pain to the patient himself. Alzheimer's disease can occur at any age of adults, and the incidence of Alzheimer's disease increases exponentially with age. The incidence of women is higher than that of men. The incidence of rural people is higher than that of urban people, and the incidence of high educated people is relatively low. The risk factors of AD include low education level, head trauma, sex hormone levels, family history, smoking, depressive symptoms, psychological pressure, vascular factors, lower body temperature, less social activities, mild cognitive impairment and viral infection. Alzheimer's disease usually first appeared in the hippocampus and entorhinal cortex of the limbic system, and then spread to the cerebral cortex of temporal lobe, cingulate gyrus, parietal lobe, frontal lobe and so on, which usually did not reach the occipital lobe, cerebellum, motor cortex and sensory cortex. Pathological changes of the patient's brain: Blzheimer neuritic senile plaques (senile plaques, SPs), neurofibrillary tangles (neurofibrillary, tangles, NFTs), nerve cells and synapses disappear, cerebral amyloid angiopathy and granulovacuolar deformation, the overall performance of diffuse cortical atrophy and ventricular enlargement. The pathogenesis of Alzheimer's disease is still unclear. At present, there are molecular genetic and genetic theory, inflammation theory, free radical theory, cholinergic theory, metal ion hypothesis, virus theory, oxidative stress theory, estrogen level reduction theory and so on. Most of the research is not clear what the mechanism on the basis of one-sided viewpoint, which is the result of cause. Therefore, a lot of research institutes and university institutions have also invested considerable manpower and material resources to study the pathogenesis of AD, but the effect is not ideal. At present, it is necessary to understand the disease from the overall macro level, and can not be affected by the individual and one-sided impact of the various mechanisms. It is necessary to start with the gene expression, to understand and study the pathogenesis, treatment and early detection methods of AD with the objective phenomenon of gene expression difference. Because of the complexity of neurons and limited sampling, screening age-related genes from gene expression level is the best way to study the molecular pathogenesis of Alzheimer's disease. Gene chip technology developed in recent years, shows the superiority in the screening of gene function related differences, a small sample can get massive gene expression data, which will enhance the understanding of Alzheimer's disease, and the data obtained are more objective, highly integrated. At present, due to the extensive application of high-throughput gene chip technology, various research institutes and laboratories have produced a lot of experimental data, but the information of these data is only used to a small part, and all information is often not fully excavated. The National Center for Biotechnology Information (National Center for Biotechnology Information NCBI GEO (Gene Expression) to establish the Omnibus database) is the largest collection of the most complete, free and open public gene expression database, complex biological data contains a lot of variety. These data seem to be disorganized and unavailable on the surface. However, massive biological data are bound to contain important biological laws. These laws will be the key to explain the cause of Alzheimer's disease. The gene expression profiles are huge and complex, with tens of thousands of variables. Therefore, through the use of Qlucore Omics Explorer (QOE) 3 bioinformatics software, the data by statistical analysis, the rapid conversion of 3D visualization, through principal component analysis (Principle Component, Analysis, PCA) and cluster analysis, to identify hidden in the data structure and model, with standard statistical methods and contact the difference between the sample and the sample groups and data sets and data sets. Selected common or different genes, and then through the Database for Annotation, Visualization and Integrated Discovery (DAVID) 6.7 online gene annotation system, Gene Ontology (G O) on the list of gene function enrichment analysis, from Cellular Component (CC), Biological Process (BP), Molecular Function (MF) on genes involved in three the function of annotation, enrichment, clustering. The differences and changes in the biological process, cell composition and molecular function of AD patients were obtained. Therefore, I according to the current human Alzheimer's disease gene expression data sets available, from the overall gene expression difference, with the increase of age differences in gene expression, gene expression differences in various brain regions, different stages of gene expression differences, sex related gene expression differences of pathogenesis of Alzheimer's disease research. First, using the data set GSE36980, 196 different genes of the brain of Alzheimer's disease patients and normal people were screened by two groups. The cluster analysis of expression and function of differentially expressed genes is divided into 42 annotation clusters, including GO protein localization, ion transport, cell signaling, learning and memory, and clathrin.
【學(xué)位授予單位】：南方醫(yī)科大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類(lèi)號(hào)】：R749.16;Q78

【共引文獻(xiàn)】

相關(guān)期刊論文 前1條

1 冀開(kāi)元;馬文麗;鄭文嶺;;阿爾茨海默病關(guān)于年齡因素的差異基因表達(dá)分析[J];解剖學(xué)報(bào);2015年02期

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