Modeling Down Syndrome Neural Phenotypes with Chromosomal Silencing

通过染色体沉默模拟唐氏综合症神经表型

• 批准号: 9899750
• 负责人: Jan Czerminski
• 金额: $ 3.22万
• 依托单位: UNIV OF MASSACHUSETTS MED SCH WORCESTER
• 依托单位国家: 美国
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-02-01 至 2021-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9899750
• 关键词: 3-Dimensional; Address; Alzheimer' s Disease; Alzheimer' s disease model; Alzheimer' s disease pathology; Amyloid; Amyloid deposition; Biology; Brain; Brain Diseases; Cell Culture System; Cell Culture Techniques; Cell Line; Cells; Cerebrum; Child; Chromosome 21; Chromosomes; Culture Techniques; Cultured Cells; Dementia; Dendritic Spines; Deposition; Development; Dosage Compensation (Genetics); Down Syndrome; Female; Future; Gene Expression; Gene Silencing; Genes; Genetic; Goals; Heart Abnormalities; Heterochromatin; Homebound Persons; Human; Immunofluorescence Immunologic; In Vitro; Independent Living; Intellectual functioning disability; Live Birth; Medical; Mendelian disorder; Methods; Mitochondria; Mitotic; Modeling; Molecular; Morphology; Neuroglia; Neurons; Organoids; Pathogenesis; Pathology; Pathway interactions; Patients; Phenotype; Population; Presenile Alzheimer Dementia; RNA; Respiratory Tract Infections; Senile Plaques; Study models; System; Techniques; Testing; Therapeutic; Therapeutic Intervention; Transgenes; Transgenic Organisms; Work; X Chromosome; aged; brain cell; cell type; cellular pathology; conventional therapy; extracellular; human model; hyperphosphorylated tau; improved; induced pluripotent stem cell; innovation; middle age; nerve stem cell; neuron loss; novel; novel strategies; prevent; progenitor; relating to nervous system; targeted treatment; tau Proteins; three dimensional cell culture; tool; two-dimensional

Project Summary: Down syndrome (DS), or trisomy 21, is the leading genetic cause of intellectual disability in children, with approximately 1 in 700 live births carrying an extra copy of chromosome 21. Compared to less common single gene disorders, DS pathogenesis is still poorly understood. Treatment for DS would require either identification of molecular pathways to target with conventional therapies or, potentially, chromosomal therapy to silence the many possibly disruptive genes on the trisomic chromosome. One window of therapeutic intervention lies in the Alzheimer’s disease pathology that almost all DS patients suffer from in middle age. Recently, the extra chromosome has been silenced in an inducible manner by targeted insertion of a transgene for the XIST gene into human induced pluripotent stem cells (iPSC). XIST normally silences one X chromosome in females, providing a natural mechanism of dosage compensation. Chromosomal silencing in DS cells provides a powerful isogenic and isoepigenetic model for studying DS pathology and marks the first step towards the goal of chromosomal therapy for DS patients. The proposed work will investigate the effect of silencing the extra chromosome on DS iPSC-derived neuronal cells, investigating both DS and Alzheimer- specific phenotypes. Aim 1: In order to investigate the effect that chromosomal silencing has on DS neural phenotypes in vitro, iPSCs will be differentiated into neurons using conventional two-dimensional neuronal culturing techniques and three-dimensional organoids. Cerebral organoids are a recently-developed tool that have been shown to be a useful model for human brain development, and have been used to study disorders of brain development. Neurons derived from iPSCs with two and three functional copies of Chr.21 will be compared for phenotypes that DS neural cells are thought to possess. These include an increased glia:neuron ratio, altered dendritic spine morphology, and altered mitochondrial morphology. Three-dimensional cultures will be used to investigate less well-explored pathologies such as alterations in cortical lamination. This aim will also address the important therapeutic question of whether post-mitotic cells can support chromosomal silencing. Aim 2: The same chromosomal silencing system will be used to investigate Alzheimer’s-associated neuronal phenotypes. These include intra and extracellular amyloid deposition as well as intracellular hyperphosphylated tau deposition. Due to its relatively late onset compared to general intellectual disability, the Alzheimer’s disease component of DS is most suitable for therapeutic intervention. Studying the effect of chromosomal silencing on Alzheimer’s phenotypes provides a strong model for Alzheimer’s pathogenesis while also bringing this novel strategy one step closer to therapeutics. This proposal seeks to utilize a novel chromosomal silencing technique to better model human neural phenotypes in DS and associated AD.

项目概要： 唐氏综合症 (DS) 或 21 三体症是儿童智力障碍的主要原因， 大约七百分之一的活产婴儿携带额外的 21 号染色体拷贝。与不太常见的情况相比 单基因疾病，DS的发病机制仍知之甚少。 DS 的治疗需要 识别常规疗法或可能的染色体疗法的靶向分子途径 沉默三体染色体上许多可能具有破坏性的基因。治疗的一窗 干预措施在于几乎所有 DS 患者在中年时都会患上的阿尔茨海默病病理。 最近，通过定向插入转基因，额外的染色体以可诱导的方式沉默 将 XIST 基因转化为人类诱导多能干细胞 (iPSC)。 XIST 通常会沉默一个 X 女性染色体，提供剂量补偿的自然机制。染色体沉默 DS 细胞为研究 DS 病理学提供了强大的等基因和等表遗传模型，并标志着第一个 朝着 DS 患者染色体治疗的目标迈出了一步。拟议的工作将调查的影响 沉默 DS iPSC 衍生神经元细胞上的额外染色体，研究 DS 和阿尔茨海默病 特定的表型。 目标1：为了研究染色体沉默对DS神经表型的影响 在体外，iPSC 将使用传统的二维神经元培养分化为神经元 技术和三维类器官。大脑类器官是最近开发的一种工具 被证明是人类大脑发育的有用模型，并已用于研究大脑疾病 发展。来自具有两个和三个 Chr.21 功能拷贝的 iPSC 的神经元将进行比较 DS 神经细胞被认为具有的表型。这些包括增加胶质细胞：神经元比率，改变 树突棘形态和改变的线粒体形态。三维文化将被用来 研究尚未充分探索的病理学，例如皮质分层的改变。这一目标还将解决 有丝分裂后细胞是否可以支持染色体沉默这一重要的治疗问题。 目标 2：相同的染色体沉默系统将用于研究阿尔茨海默氏症相关疾病 神经元表型。这些包括细胞内和细胞外淀粉样蛋白沉积以及细胞内淀粉样蛋白沉积。 过度磷酸化的 tau 沉积。由于与一般智力障碍相比，其发病相对较晚， DS 的阿尔茨海默病成分最适合治疗干预。研究效果 阿尔茨海默病表型的染色体沉默为阿尔茨海默病的发病机制提供了强有力的模型 也使这种新颖的策略更接近治疗。 该提案旨在利用一种新颖的染色体沉默技术来更好地模拟人类神经 DS 和相关 AD 中的表型。