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.

亨廷顿氏病（HD）是一种由灾难性和致命的神经退行性疾病。 在25岁以上发现了潜在的基因突变中的多态CAG CAG重复体 尽管如此，尽管如此，但仍然没有治疗或有效的治疗方法 经过时间和CAG长度依赖性的体细胞扩张和最新的全基因组关联研究 （GWAS）支持躯体CAG扩展作为致病过程的第一步，以引起细胞 毒性和最终临床疾病。 发病年龄，其中是LIG1，编码DNA连接酶1。DNA连接酶1的生物学功能与 它在体细胞CAG扩展中，但是该基因也可能处理影响细胞毒性的基因。 总体而言，疾病修饰的机械基础仍然晦涩难懂 可以在人类遗传数据中区分染色体：一个由预测的有害SNP标记 编码K854N替换是开始延迟的，而另一个则与Lig1表达增加有关 并且是为了发作，在这项研究中，我们将进行实验以测试植根于人文的假设 了解这些Lig1修饰符效应的功能构造。 HD的小鼠模型测试引入小鼠Lig1基因的K> n变量突变的影响， 并测试LIG1上调的影响，对AIM 2中的体细胞cag扩展和表型表达 我们将使用HD患者衍生的和同基因神经元细胞和带有Lig1修饰符的Neurbon 等位基因以鉴定其细胞和分子后果，并测试对由表型产生的影响 AIM 3中的HTT突变我们将进行LIG1 K845N的生化，结构和功能分析 变体。 Lig1修改患者的疾病，最终启发可用于疾病的治疗途径 修改治疗。