阿尔茨海默病（Alzheimer’s disease, AD）病因不清，随着年龄积累的线粒体DNA(mitochondrial DNA,mtDNA)的突变(点突变、重组)而导致的线粒体功能障碍可能是AD的上游机制。目前未发现同AD相关的特异的mtDNA点突变，对脑组织的mtDNA重组的研究长期受限于方法学。本课题前期从新鲜冰冻的脑组织分离线粒体，提取mtDNA，直接测序，并优化分析软件，该方法突破以前无法对mtDNA基因组重组整体状况进行研究的限制。前期资料发现mtDNA基因组重组随机发生，种类繁多，发现的种类超过以前报道的总和。我们同时发现AD患者脑具有较高的mtDNA重组率。本课题以此为基础，扩大样本量进一步验证。通过比较50个AD患者脑和50个年龄匹配非AD患者脑的mtDNA突变的差别,目的是寻找mtDNA突变规律，建立mtDNA异常突变和AD病理学的联系，寻找AD可能的病因。

The etiology of Alzheimer’s disease (AD) is unclear, and the aging is the main risk factor of AD. Mitochondrial dysfunction may play a central role in the pathologic process of Alzheimer’s disease (AD), but there is still a scarcity of data that directly links the pathology of AD with the alteration of mitochondrial DNA（mtDNA）. We developed an excellent protocol to identify the all recombinants from given sample, which combing different techniques such as isolated mitochondria from samples, extracted mtDNA, sequenced and bioinformatics. The new protocol can capture all different type of mtDNA recombinant fragments from given samples and allow analyzing the frequency of recombinant of samples which cannot be completed before. Our preliminary data showed that there are three types of mitochondrial DNA (mtDNA) rearrangements have been seen in post mortem human brain tissue from patients with AD. These observed rearrangements include a deletion, F-type rearrangement, and R-type rearrangement. We detected a high level of mtDNA rearrangement in brain tissue from cognitively normal subjects, as well as the patients with Alzheimer's disease (AD). The rate of rearrangements was calculated by dividing the number of positive rearrangements by the coverage depth. The rearrangement rate was significantly higher in AD brain tissue than in control brain tissue (17.9 versus 6.7%; p=0.0052). Of specific types of rearrangement, deletions were markedly increased in AD (9.2% versus 2.3%; p=0.0005). The proposal is seeking to expand the size of samples to verify these preliminary data. We are planning to explore comprehensive assessment of mtDNA rearrangement events and point mutations of mtDNA in 50 AD brain tissue and 50 aging matched brain tissue. By comparing the difference of mtDNA recombinants from patients and controls, and the difference of mtDNA recombinants from the affected region and unaffected region of AD brain, aim to build up the linker between mtDNA recombinants and AD pathology.

阿尔茨海默病(Alzheimer’s Disease, AD)又称老年性痴呆,是老年人群中最常见的神经退行性病变之一。绝大多数的AD病例为散发病例,通常隐袭起病,缓慢、进行性进展。随着全球范围的人口老龄化问题越来越严重,AD作为与年龄相关疾病,患病率日益增长。线粒体功能障碍是AD发生发展过程中非常重要的机制之一,其线粒体质量控制途径受损,包括线粒体动力学失衡、线粒体DNA损伤修复异常以及线粒体自噬异常等,是当前的研究热点。 在阿尔茨海默病的病理过程中线粒体功能障碍可能发挥重要的中心作用，但仍缺乏有足够数据，直接将AD的病理与线粒体DNA的改变联系起来。目前未发现同AD相关的特异的mtDNA点突变，对脑组织的mtDNA重组的研究长期受限于方法学。本研究旨在对AD脑组织中mtDNA重排事件进行综合评价。 前期资料发现mtDNA基因组重组随机发生，种类繁多，发现的种类超过以前报道的总和。我们同时发现AD患者脑具有较高的mtDNA重组率。本课题以此为基础，扩大样本量进一步验证。通过比较50个AD患者脑和50个年龄匹配非AD患者脑的mtDNA突变的差别,目的是寻找mtDNA突变规律，建立mtDNA异常突变和AD病理学的联系，寻找AD可能的病因。 通过测序表面，在阿尔兹海默症患者中线粒体重组明显高于对照 (17.9%: 6.7%; p = 0.0052),而线粒体基因组的缺失也是明显高于对照 (9.2%:2.3%; p = 0.0005). 结果表明，线粒体DNA的缺陷在阿尔兹海默症的发生发展中有着很重要的影响。