Dissecting the role of DNA Ligase 1 in Huntington's disease

剖析 DNA 连接酶 1 在亨廷顿舞蹈病中的作用

• 批准号: 10733111
• 负责人: Ihn Sik Seong
• 金额: $ 63.07万
• 依托单位: MASSACHUSETTS GENERAL HOSPITAL
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-07-25 至 2028-06-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10733111
• 关键词: Age; Age of Onset; Alleles; Binding; Biochemical; Biological Assay; Biological Process; Biology; CAG repeat; CRISPR-mediated transcriptional activation; Cells; Cellular Stress; Cessation of life; Chromosomes; Clinical; Complex; DNA Damage; DNA Ligases; DNA Ligation; DNA Repair; DNA Sequence Alteration; Data; Disease; Family; Gene Modified; Gene Mutation; Genes; Genetic Recombination; Genetic Transcription; Genetic Variation; Haplotypes; Health Care Costs; Histologic; Homologous Gene; Human; Human Genetics; Huntington Disease; Huntington gene; Inherited; Knock-in Mouse; Length; Ligase; Long-Term Care; Mass Spectrum Analysis; Modeling; Modification; Molecular; Mus; Mutation; Neurobehavioral Manifestations; Neurodegenerative Disorders; Neuronal Differentiation; Neurons; Nuclear; Onset of illness; Pathogenesis; Pathogenicity; Pathology; Patients; Phenotype; Process; Proteins; Research; Role; Series; Structure; Substrate Specificity; Testing; Therapeutic; Therapeutic Intervention; Time; Tissues; Toxic effect; Up-Regulation; Variant; X-Ray Crystallography; brain tissue; cell free DNA; effective therapy; emotional symptom; experimental study; functional outcomes; gene discovery; genetic manipulation; genome wide association study; induced pluripotent stem cell; insight; motor symptom; mouse model; multiplex assay; mutant; nerve stem cell; new therapeutic target; novel; protein purification; repaired; response; seal; targeted treatment; transcriptome

Huntington’s disease (HD) is a devastating and fatal neurodegenerative disorder caused by the expansion of a polymorphic CAG repeat in the HTT gene. Although the underlying genetic mutation was discovered over 25 years ago, there is still no cure or effective treatment despite extensive efforts. The CAG repeat mutation undergoes time- and CAG length-dependent somatic expansion and recent genome-wide association studies (GWAS) support somatic CAG expansion as the first step of the pathogenic process, required to elicit cellular toxicity and ultimately clinical disease. GWAS identified several genes involved in DNA repair as modifiers of age of onset, among which is LIG1, encoding DNA ligase 1. The biological function of DNA ligase 1 implicates it in somatic CAG expansion, however this gene may also alter processes that impact on cellular toxicity. Overall, the mechanistic underpinnings of disease modification remain obscure. Independent LIG1 modifier chromosomes can be distinguished in the human genetic data: one, tagged by a predicted deleterious SNP encoding a K854N substitution, is onset-delaying, while another is associated with increased LIG1 expression and is onset-hastening. In this study, we will perform experiments to test hypotheses rooted in human genetic data to understand the functional consequences of these LIG1 modifier effects. In Aim 1 we will use a knock-in mouse model of HD to test the impact of the K>N substitution mutation introduced into the mouse Lig1 gene, and to test the impact of Lig1 upregulation, on somatic CAG expansion and phenotypic expression. In Aim 2 we will use HD patient-derived and isogenic neuronal progenitor cells and neurons harboring LIG1 modifier alleles to identify their cellular and molecular consequences and to test their impacts on phenotypes elicited by the HTT mutation. In Aim 3 we will perform biochemical, structural and functional analyses of the LIG1 K845N variant. Together, these experiments will provide novel insight into mechanisms by which genetic variation in LIG1 modifies disease in patients, ultimately revealing therapeutic avenues that can be pursued for disease- modifying treatments.

亨廷顿舞蹈症 (HD) 是一种毁灭性且致命的神经退行性疾病，由神经细胞扩张引起。 HTT 基因中存在多态性 CAG 重复序列。尽管潜在的基因突变被发现超过 25 多年前，尽管进行了广泛的努力，但仍然没有治愈或有效的治疗方法。 CAG重复突变 经历时间和 CAG 长度依赖性体细胞扩增和最近的全基因组关联研究 (GWAS) 支持体细胞 CAG 扩张作为致病过程的第一步，这是引发细胞 毒性和最终的临床疾病。 GWAS 鉴定了几个参与 DNA 修复的基因作为修饰因子 发病年龄，其中LIG1编码DNA连接酶1。DNA连接酶1的生物学功能涉及 它参与体细胞 CAG 扩增，但该基因也可能改变影响细胞毒性的过程。 总体而言，疾病修饰的机制基础仍然不清楚。独立LIG1修饰符 染色体可以在人类遗传数据中区分：一条，由预测的有害 SNP 标记 编码 K854N 取代，具有起效延迟作用，而另一个则与 LIG1 表达增加相关 并且是加速发作的。在这项研究中，我们将进行实验来检验植根于人类遗传的假设 数据来了解这些 LIG1 修饰剂效应的功能后果。在目标 1 中，我们将使用敲入 HD 小鼠模型，用于测试引入小鼠 Lig1 基因的 K>N 替代突变的影响， 并测试 Lig1 上调对体细胞 CAG 扩增和表型表达的影响。目标 2 我们将使用 HD 患者来源的同基因神经元祖细胞和含有 LIG1 修饰剂的神经元 等位基因，以确定其细胞和分子后果，并测试其对表型的影响 HTT突变。在目标 3 中，我们将对 LIG1 K845N 进行生化、结构和功能分析 变体。总之，这些实验将为了解遗传变异的机制提供新的见解。 LIG1 可以改变患者的疾病，最终揭示疾病的治疗途径—— 修改治疗方法。