Tet-mediated Epigenetic Regulation in Alzheimer's Disease

项目摘要 AD是由神经元连接的进行性衰退最终导致神经元死亡引起的。损失 稳态神经元功能导致患者严重的认知能力下降，抑制了他们的功能， 日常生活中没有医疗保健提供者的广泛帮助。AD的病因在很大程度上是未知的; 然而，我们目前的认识认识是，遗传、表观遗传和环境因素都起着作用 在疾病中。由于表观遗传修饰受环境因素和影响基因的影响， 它们在个体的遗传组成和表型之间起着中介作用。 特色因此，表观遗传修饰有望解释大部分的缺失， AD的遗传性以及表观基因组、TET 2和AD之间的几种联系已经被发现。这里 我们的目标是确定与AD相关的新的TET 2变体，并研究这些变体和减少 TET 2的丰富导致甲基化组的失调以及这些改变如何导致AD 发病机制通过研究泰特对AD的影响，我们将进一步了解TET在AD中的作用 DNA羟甲基化在受AD影响最严重的大脑区域中发挥作用，以及这些变化是如何发生的 影响基因表达、AD病理学以及学习和记忆。此前，我们的实验室阐明了 5 mC和5 hmC修饰在神经发育和几种神经系统疾病中起作用。此外，我们的实验室 确定了AD患者相对于对照组的羟甲基化位点差异，并表征了 AD小鼠模型中的总体5 hmC患病率。最近，我们制作了初步数据， 在早发性阿尔茨海默病患者中富集TET 2功能丧失变体（约1.4%病例 对比0.12%对照）。基于这些先前的发现，我们将操纵5 hmC修饰谱， 阿尔茨海默病小鼠模型，研究泰特酶的失调如何导致AD 发病机制结合甲基化组的表征（通过5 hmC捕获测量），我们将 分析基因表达（通过RNA-seq测量）和AD进展（通过行为测定测量），以及 Aβ斑块和神经元群体的免疫组织化学）在野生型和5XFAD（一种β-淀粉样斑块）中 AD小鼠模型。将对从皮质和海马采集的组织进行这些试验。我们 长期目标是鉴定新的AD相关TET 2突变以及泰特酶突变如何破坏 5 hmC签名的余额。我们的研究结果可能会提供更深入的了解基因组变异，有助于 AD风险、可能用作AD生物标志物的特异性5 hmC谱以及5 hmC变异 赋予AD致病性或保护作用的特征。

PROJECT SUMMARY AD is caused by the progressive decay of neuronal connections ultimately leading to neuronal death. Loss of homeostatic neuronal function leads to severe cognitive decline in patients, inhibiting their ability to function in day-to-day life without extensive help from healthcare providers. The causes of AD are largely unknown; however, our current understanding recognizes that genetic, epigenetic, and environmental factors play a role in the disease. As epigenetic modifications are influenced by environmental factors and influence gene expression, they serve as a mediator between an individual’s genetic composition and phenotypic characteristics. Thus, epigenetic modifications hold promise to explain a significant portion of the missing heritability of AD, and several links between the epigenome, TET2, and AD have already been uncovered. Here we aim to identify novel TET2 variants associated with AD, and examine both how these variants and a reduction in abundance of TET2 lead to dysregulation of the methylome and how these alterations contribute to AD pathogenesis. Through examining the influence of TET on AD, we will advance our understanding on the role DNA hydroxymethylation plays in the brain regions most adversely affected by AD and how these changes influence gene expression, AD pathology, and learning and memory. Previously, our lab shed light on the role 5mC and 5hmC modifications play in neurodevelopment and several neurological disorders. Additionally, our lab identified differentially hydroxymethylated sites enriched in AD patients relative to controls and characterized the global 5hmC prevalence in an AD mouse model. More recently, we produced preliminary data to show enrichment of TET2 loss of function variants in individuals with early onset Alzheimer’s disease (~1.4% cases versus 0.12% controls). Building upon these previous findings, we will manipulate 5hmC modification profiles in an Alzheimer’s disease mouse model to investigate how dysregulation of TET enzymes contributes to AD pathogenesis. In conjunction with characterization of the methylome (measured via 5hmC Capture), we will analyze gene expression (measured via RNA-seq) and AD progression (measured via behavioral assays, and immunohistochemistry of Aβ plaques and neuronal populations) in wildtype and 5XFAD, a beta-amyloid plaque AD mouse model. These assays will be performed on tissues collected from the cortex and hippocampus. Our long-term goal is to identify novel AD associated TET2 mutations and how mutations in TET enzymes disrupt the balance of 5hmC signatures. Our findings may provide greater insight on genomic variants that contribute to AD risk, specific 5hmC profiles with the potential to be used as biomarkers for AD as well as variations in 5hmC profiles which confer AD pathogenicity or protection.