Altered reverse transcriptase-dependent gene diversification mechanisms in Alzheimer's disease brains

阿尔茨海默病大脑中逆转录酶依赖性基因多样化机制的改变

基本信息

批准号：
10758986
负责人：
JEROLD CHUN
金额：
$ 8.38万
依托单位：
SANFORD BURNHAM PREBYS MEDICAL DISCOVERY INSTITUTE
依托单位国家：
美国
项目类别：
财政年份：
2020
资助国家：
美国
起止时间：
2020-04-01 至 2025-01-31
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10758986
关键词：
Affect Alzheimer&apos s Disease Alzheimer&apos s disease brain Alzheimer&apos s disease therapeutic Alzheimer&apos s disease therapy Amyloid beta-Protein Precursor Animal Experiments Animal Model Autopsy Back Biological Models Brain Brain region Cell model Complementary DNA Copy Number Polymorphism DNA DNA strand break Data Disease Down Syndrome FDA approved Female Foundations Gene Proteins Genes Genetic Recombination Genetic Transcription Genome Genomics HIV Human IACUC In Situ Hybridization Institutional Review Boards Knowledge Methodology Modeling Molecular Molecular Biology Molecular Neurobiology Molecular Target Mosaicism Nature Neurofibrillary Tangles Neuroglia Neurons Nucleotides Pathogenicity Patients Pattern Prevalence Publishing RNA RNA-Directed DNA Polymerase Reporting Reverse Transcriptase Inhibitors Role Sampling Senile Plaques Testing Therapeutic Toxic effect Validation Variant aged brain tissue cell type ds-DNA familial Alzheimer disease genetic variant human embryonic stem cell induced pluripotent stem cell integration site male mosaic nanobodies neurobiological mechanism neuropathology new therapeutic target novel sequencing platform sex therapeutic target

项目摘要

PROJECT SUMMARY/ABSTRACT We have identified somatic gene recombination (SGR) in neurons of the human brain, with particular relevance to sporadic Alzheimer’s disease (SAD) (Nature 563, 639-645 (2018)). This discovery represents a new and functionally significant aspect of genomic mosaicism (eLife;4:e05116 (2015)) that has genuine therapeutic potential through newly identified molecular targets. Indeed, we found that SGR, acting on the AD gene for Amyloid Precursor Protein (APP), produces thousands of distinct forms of APP, some of which are enriched in or unique to AD. The APP gene variations related to AD that were analyzed thus far include copy number variations (CNVs) and at least 11 single-nucleotide variations (SNVs) that were previously reported as pathogenic in familial AD, yet that arose somatically and mosaically in SAD; these variations were absent from non-diseased neurons. SGR utilizes reverse transcriptase (RT) activity on transcribed RNAs that, combined with DNA strand-breaks and APP gene transcription, produce double-stranded DNA that is retro-inserted back into the genome to form “genomic cDNAs” (gencDNAs). These published data contribute to the scientific foundation on which the current proposal will build, to test the hypothesis that altered SGR, involving brain-specific reverse transcriptases, functionally contributes to AD and affects multiple genes, providing novel targets for AD therapies. Postmortem IRB-approved and de-identified brain samples from validated AD donors of both sexes will be compared to non-diseased controls, while IACUC-approved animal experiments will model SGR and its AD-relevant endpoints. Three Aims will be pursued over 5 years. Aim 1 will define the molecular neurobiology of APP gencDNA diversity and identify new SGR genes enhanced in AD brains. Aim 2 will determine expression and function of SGR genes in AD brain and model systems. Aim 3 will identify genes responsible for RT SGR activity within normal and AD brains. This proposal will thus open new vistas into AD via novel SGR mechanisms and will identify new therapeutic targets for the treatment of AD.

项目概要/摘要我们在人脑神经元中发现了体细胞基因重组 (SGR)，与散发性阿尔茨海默病 (SAD) 特别相关（Nature 563, 639-645 (2018)），这一发现代表了基因组嵌合现象的一个新的、具有功能意义的方面。 (eLife;4:e05116 (2015)) 通过新发现的分子靶标具有真正的治疗潜力事实上，我们发现 SGR 作用于 AD。淀粉样前体蛋白 (APP) 基因产生数千种不同形式的 APP，其中一些在 AD 中丰富或独特。迄今为止分析的与 AD 相关的 APP 基因变异至少包括拷贝数变异 (CNV)。 11 种单核苷酸变异 (SNV) 先前被报道为家族性 AD 致病性，但在 SAD 中以体细胞和镶嵌方式出现；这些变异在非患病 SGR 中不存在。转录酶（RT）对转录RNA的活性，与DNA链断裂和APP基因转录相结合，产生双链DNA，该双链DNA被逆插入基因组中形成“基因组cDNA”（gencDNA）。当前提案将建立在科学基础上，以测试改变 SGR（涉及大脑特异性逆转录酶）的假设，在功能上有助于 AD 并影响多个基因，为 AD 治疗提供新的靶点。来自经过验证的 AD 性别捐献者的 IRB 批准和去识别化的大脑样本将与未患病对照进行比较，而 IACUC 批准的动物实验将模拟 SGR 及其 AD 相关终点，并将在 5 年内实现。目标 1 将定义 APP gencDNA 多样性的分子神经生物学，并识别 AD 大脑中增强的新 SGR 基因。目标 2 将确定 AD 大脑和模型系统中 SGR 基因的表达和功能。目标 3 将识别正常和 AD 大脑中负责 RT SGR 活性的基因，因此该提案将通过新颖的 SGR 机制为 AD 开辟新的前景，并将确定治疗 AD 的新治疗靶点。