Exploring a role for LINE1 retrotransposons in neurodegenerative disease

探索 LINE1 逆转录转座子在神经退行性疾病中的作用

• 批准号: 8805859
• 负责人: JOHN Lawrence GOODIER
• 金额: $ 8.1万
• 依托单位: JOHNS HOPKINS UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-05-01 至 2017-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8805859
• 关键词: Accounting; Age; Alzheimer' s Disease; Amyloid beta-Protein; Amyotrophic Lateral Sclerosis; Antisense RNA; Area; Binding; Biological Assay; Biology; Brain; Cell Death; Cell Line; Cells; Chemicals; Co-Immunoprecipitations; Collaborations; Cytoplasmic Granules; DNA Methylation; Databases; Disease; Disease susceptibility; Elements; Epigenetic Process; Etiology; Future; Genes; Genetic Medicine; Genetic Transcription; Genome; Grant; Health; Hospitals; Human; Human Genome Project; Immunohistochemistry; Individual; Institutes; Investigation; Laboratories; Letters; Literature; Location; Malignant Neoplasms; Mediating; Medical; Minor; Monitor; Morphology; Mutation; Nerve Degeneration; Neurodegenerative Disorders; Neurology; Neurons; Nucleic Acids; ORF2 protein; Paste substance; Pathogenesis; Pathology; Patients; Predisposition; Process; Proteins; Pseudogenes; RNA; RNA Interference; RNA-Binding Proteins; RNA-Directed DNA Polymerase; Research; Retroposon; Retrotransposition; Retrotransposon; Reverse Transcriptase Polymerase Chain Reaction; Reverse Transcription; Ribonucleoproteins; Role; Sampling; Science; Serum; Somatic Cell; Source; Stem cells; Stress; Structure; Susceptibility Gene; Testing; Therapeutic; Tissue Sample; Tissues; Up-Regulation; Variant; Virus; aging population; base; brain tissue; cell type; chromatin remodeling; effective therapy; endonuclease; human DNA; immunocytochemistry; induced pluripotent stem cell; insight; interest; link protein; medical schools; mutant; novel; novel therapeutics; nucleoside inhibitor; particle; protein aggregate; protein aggregation; protein expression; protein misfolding; transposon/insertion element

DESCRIPTION (provided by applicant): Understanding the causes of neurodegenerative diseases with the aim of developing effective treatments is a significant medical challenge. Much effort has been expended identifying susceptibility genes for amyotrophic lateral sclerosis (ALS) and Alzheimer's (AD) disease. A number of genes have been found, each explaining a minor percentage of familial cases and contributing little to our understanding of the pathogenesis of sporadic cases. However, one common feature of many neurodegenerative diseases is protein aggregation, and it is widely thought that revealing the processes of cytoplasmic aggregate formation is key to better understanding the disease. We propose a novel hypothesis: rather than mutations at single gene locus, increased expression of ubiquitous LINE1 (L1) retrotransposons in the brains of ALS or AD patients, perhaps from many locations in the genome, contribute to the disease pathology. We predict that the consequent increase in cellular levels of the L1-encoded ORF1p RNA-binding protein could increase its binding to proteins of significance for ALS or AD and promote their sequestration in stress granules and other cytoplasmic aggregates. Furthermore, a corresponding increase in L1 ORF2 protein could account for increased levels of reverse transcriptase activity that have been detected in sera of ALS patients. LINE1 retrotransposons are non-viral mobile DNA elements that duplicate themselves by a "copy and paste" mechanism using an RNA intermediate. The Human Genome Project estimated that over 500,000 L1 copies occupy 17% of human DNA, although it is believed that only about 100 of these remain potentially active in any individual. L1 retrotransposition has also been responsible for the insertion of over a million non- autonomous Alu retroposons and thousands of processed pseudogenes. The cell in turn has evolved defenses against unrestricted retrotransposition, including DNA methylation, chromatin remodeling, nucleic acid editing, and RNA interference. However, recent investigations show that these defenses are occasionally relaxed, leading to increased retrotransposon activity in certain somatic cell types, including stem cells, some cancers, and notably neuronal cells in the human brain. Using immunocytochemistry, RNA analyses, coimmunoprecipitation, and a functional assay for L1 ORF2 reverse transcriptase activity, we will examine brain tissue and derived iPS cell lines, mainly from ALS patients but also including AD samples, and compare these with age-matched controls to ascertain if L1 RNA and protein expression is elevated in the disease state. We will assay for alteration in the size, number, and morphology of L1 ORF1p-mediated cytoplasmic RNA granule formation in patient samples and monitor for association and colocalization of ALS/AD-associated proteins with the L1. Common mutations in both ORF1p and disease susceptibility proteins will be assayed for their effects on coaggregation.

描述（由申请人提供）：了解神经退行性疾病的原因，目的是开发有效治疗是一个重大的医学挑战。已经花费了很多努力来识别肌萎缩性侧索硬化症（ALS）和阿尔茨海默氏病（AD）疾病的易感基因。已经发现了许多基因，每个基因都解释了一小部分家族病例，几乎没有什么贡献我们对零星病例的发病机理的理解。但是，许多神经退行性疾病的一个共同特征是蛋白质聚集，人们普遍认为揭示细胞质骨料形成过程是更好地理解疾病的关键。我们提出了一个新的假设：在单基因基因座上而不是突变，而是在ALS或AD患者的大脑中无处不在的Line1（L1）逆转录座子的表达增加，也许来自基因组的许多位置，从而有助于疾病病理学。我们预测，随之而来的L1代码ORF1P RNA结合蛋白的细胞水平会增加其与ALS显着性蛋白质的结合或AD的结合，并促进其在应激颗粒和其他细胞质聚集体中的隔离。此外，L1 ORF2蛋白的相应增加可以解释ALS患者血清中检测到的逆转录酶活性的水平。 Line1逆转录座子是非病毒移动DNA元素，使用RNA中间体通过“副本和粘贴”机制复制自己。人类基因组项目估计，超过500,000 L1副本占人类DNA的17％，尽管人们认为其中只有100个在任何个体中仍然具有潜在的活性。 L1逆转录置位还负责插入超过一百万个非自主的Alu逆转录子和数千个加工的假基因。该细胞反过来又进化了防御反对反逆转录的防御能力，包括DNA甲基化，染色质重塑，核酸编辑和RNA干扰。然而，最近的研究表明，这些防御偶尔会放松，导致在某些体细胞类型中的逆转录转座活性增加，包括干细胞，某些癌症，以及人脑中尤其是神经元细胞。 使用免疫细胞化学，RNA分析，共免疫沉淀以及对L1 ORF2逆转录酶活性的功能测定，我们将检查脑组织和衍生的IPS细胞系，主要来自ALS患者，但也包括AD样品，包括AD样品，并将其与年龄匹配的对照组相比，以确定L1 RNA和蛋白质的表达是否升高。我们将测定改变患者样品中L1 ORF1P介导的细胞质RNA颗粒形成的大小，数量和形态的改变，并监测ALS/AD相关蛋白与L1的关联和共定位。 ORF1P和疾病易感性蛋白的常见突变将被测定，以分析其对凝集的影响。

项目成果

Transcriptional profiling of HERV-K(HML-2) in amyotrophic lateral sclerosis and potential implications for expression of HML-2 proteins.

• DOI: 10.1186/s13024-018-0275-3
• 发表时间: 2018-08-02
• 期刊: Molecular neurodegeneration
• 影响因子: 15.1
• 作者: Mayer J;Harz C;Sanchez L;Pereira GC;Maldener E;Heras SR;Ostrow LW;Ravits J;Batra R;Meese E;García-Pérez JL;Goodier JL
• 通讯作者: Goodier JL

Engineered LINE-1 retrotransposition in nondividing human neurons.

• DOI: 10.1101/gr.206805.116
• 发表时间: 2017-03
• 期刊: Genome research
• 影响因子: 7
• 作者: Macia A;Widmann TJ;Heras SR;Ayllon V;Sanchez L;Benkaddour-Boumzaouad M;Muñoz-Lopez M;Rubio A;Amador-Cubero S;Blanco-Jimenez E;Garcia-Castro J;Menendez P;Ng P;Muotri AR;Goodier JL;Garcia-Perez JL
• 通讯作者: Garcia-Perez JL

Restricting retrotransposons: a review.

• DOI: 10.1186/s13100-016-0070-z
• 发表时间: 2016
• 期刊: Mobile DNA
• 影响因子: 4.9
• 作者: Goodier JL