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: 9258288
• 负责人: Jan Czerminski
• 金额: $ 3.07万
• 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/9258288
• 关键词: Address; Alzheimer' s Disease; Amyloid; Amyloid deposition; Biology; Brain; Brain Diseases; Cell Culture System; Cell Line; Cells; Cerebrum; Child; Chromosomes; Chromosomes, Human, Pair 21; Culture Techniques; Cultured Cells; Dementia; Dendritic Spines; Deposition; Development; Dimensions; Dosage Compensation (Genetics); Down Syndrome; Female; Future; Gene Expression; 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; One-Step dentin bonding system; 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; 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： 唐氏综合征（DS），或21三体，是儿童智力残疾的主要遗传原因， 大约每700个活产婴儿中就有一个携带额外的21号染色体拷贝。与不太常见的 单基因疾病，DS的发病机制仍然知之甚少。DS的治疗需要 鉴定以常规疗法或潜在染色体疗法为靶分子途径 来抑制三体染色体上许多可能具有破坏性的基因。一个治疗窗口 干预的关键在于阿尔茨海默病的病理，几乎所有的DS患者在中年遭受。 最近，额外的染色体已经通过定向插入转基因以可诱导的方式沉默 将XIST基因导入人类诱导多能干细胞（iPSC）。XIST通常使一个X静音 染色体，提供了剂量补偿的自然机制。染色体沉默 DS细胞为研究DS病理学提供了一个强大的等基因和等表观遗传模型， 朝着DS患者的染色体治疗目标迈出了一步。拟议的工作将调查的影响 沉默DS iPSC衍生的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。 目的1：为了研究染色体沉默对DS神经表型的影响， 在体外，iPSC将使用常规的二维神经元培养分化成神经元 技术和三维类器官。大脑类器官是最近开发的工具， 已被证明是人类大脑发育的有用模型，并已被用于研究大脑疾病 发展将比较来源于具有两个和三个功能性拷贝的Chr.21的iPSC的神经元， DS神经细胞被认为具有的表型。这些包括增加胶质细胞：神经元比例，改变 树突棘形态和改变的线粒体形态。三维培养将用于 研究较少研究的病理学，如皮质分层的改变。这一目标还将解决 有丝分裂后的细胞是否能支持染色体沉默的重要治疗问题。 目的2：同样的染色体沉默系统将用于研究阿尔茨海默病相关的 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。由于与一般智力残疾相比发病相对较晚， DS的阿尔茨海默病成分最适合用于治疗干预。影响的研究 阿尔茨海默氏症表型上的染色体沉默为阿尔茨海默氏症的发病机制提供了一个强有力的模型， 也使这种新的策略更接近治疗方法。 该提议寻求利用一种新的染色体沉默技术来更好地模拟人类神经系统。 DS和相关AD中的表型。