Isoform-dependent effects of tau phosphorylation in Alzheimer's disease

阿尔茨海默病中 tau 磷酸化的异构体依赖性效应

基本信息

批准号：
10745286
负责人：
Nima Nick Naseri
金额：
$ 7.18万
依托单位：
UNIVERSITY OF PENNSYLVANIA
依托单位国家：
美国
项目类别：
财政年份：
2022
资助国家：
美国
起止时间：
2022-09-01 至 2025-08-31
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10745286
关键词：
Acceleration Address Adult Affect Affinity Age Aging Alternative Splicing Alzheimer&apos s Disease Alzheimer&apos s disease model Alzheimer&apos s disease patient Behavior Binding Biological Assay Biology Biophysics Brain Cells Charge Chemicals Chemistry Complement Data Dementia Development Dimensions Disease Disease Progression Dissociation Doctor of Philosophy Embryo Embryonic Development FTD with parkinsonism Fetal Tissues Fluorescence Functional disorder Future Goals Grant Heterogeneity Hippocampus Impairment In Vitro Injections Lead Length Link MAPT gene Measures Microtubule Polymerization Microtubule Stabilization Microtubules Molecular Conformation Mus Mutate Mutation Nerve Degeneration Neurodegenerative Disorders Neurons Neurosciences Pathologic Pathology Pattern Phosphorylation Phosphorylation Site Play Positioning Attribute Protein Biosynthesis Protein Isoforms Proteins Research Personnel Resolution Role Science Site Solubility Spectrum Analysis Structure Tauopathies Techniques Testing Total Internal Reflection Fluorescent Training Transgenic Mice Tubulin Tubulin Interaction age related aging brain biophysical techniques chemical synthesis driving force experimental study fetal gain of function hyperphosphorylated tau in vivo insight mouse model nervous system disorder neuropathology novel peptide chemical synthesis post-doctoral training proteostasis single molecule single-molecule FRET skills tau Proteins tau aggregation tau function tau mutation tau-1 tool

项目摘要

Neuropathology of the microtubule-associated protein tau is central to numerous devastating neurological disorders termed tauopathies, including Alzheimer's disease (AD). Tau promotes microtubule (MT) polymerization and stability via its interaction with tubulin, regulated by phosphorylation to tau in multiple domains. Six major tau isoforms are alternatively spliced in an age-dependent manner. While FTDP-17-causing mutations in tau show isoform-dependent effects on aggregation and microtubule stabilization, there are no tau mutations linked to AD. Meanwhile, isoform-dependent effects of phosphorylation to tau remain unexplored. Interestingly, I discovered that numerous AD-relevant phospho-tau (pTau) sites are also phosphorylated during normal embryonic development, and then decrease over age. Why are specific pTau sites, which are correlated with disease, also expressed during normal development? The parallel between the developmental and pathological states suggests that understanding the function of pTau during development would elucidate the mechanism(s) underlying tau pathology in AD. My preliminary data indicate that i) numerous AD-relevant pTau sites are expressed in normal embryonic mouse brains, ii) pTau is soluble and likely functional in fetal tissue, iii) phosphorylation at sites T231, S235 and S262 impair MT polymerization by the fetal tau isoform but not an adult isoform, and iv) these same pTau sites accelerate aggregation of the adult isoform over the fetal isoform. Recent evidence demonstrates that tau initiates nucleation of MT polymerization. Based on my preliminary data, ! propose that tau phosphorylation has isoform-dependent effects, in which specific pTau sites are detrimental to adult isoforms in an aging brain but functional in the fetal isoform in developing brains. I will explore two aims which will provide critical insight to understanding the effects of tau phosphorylation in each isoform. In Aim 1, I will determine the relationship between the interaction between pTau with both soluble tubulin and stabilized MTs in each isoform. In Aim 2, I will test for the relationship between pTau sites which cause tau to dissociate from MTs with those that accelerate its aggregation and/or seeding activity. Importantly, our lab has uniquely synthesized full-length tau with genuine chemical phosphorylation at sites T231, S235 and S262 for these studies. These experiments will be tested using multiple platforms including these chemically-synthesized proteins, high-resolution single-molecule techniques (single-molecule FRET, fluorescence correlative spectroscopy, and time-lapse TIRF microscopy), and injection of semi-synthesized proteins into mouse brains. The investigator has 6+ years of expertise in working with the biological assays and mouse models described here, and the sponsor and collaborators will guide training in the described chemical and biophysical techniques. I anticipate that my findings will elucidate the function of tau in developing neurons, and will provide insight into mechanisms of pathological tau hyperphosphorylation across numerous tauopathies including AD.

微管相关蛋白 tau 的神经病理学是许多破坏性神经系统疾病的核心称为tau蛋白病的疾病，包括阿尔茨海默病(AD)。 Tau 促进微管 (MT) 通过与微管蛋白相互作用实现聚合和稳定性，并通过多种途径磷酸化 tau 来调节域。六种主要 tau 亚型以年龄依赖性方式交替剪接。虽然 FTDP-17 引起 tau 突变对聚集和微管稳定表现出异构体依赖性影响，但不存在 tau 与 AD 相关的突变。与此同时，tau 磷酸化的异构体依赖性效应仍未被探索。有趣的是，我发现许多与 AD 相关的磷酸化 tau (pTau) 位点也在正常胚胎发育，然后随着年龄的增长而下降。为什么特定的 pTau 位点是相关的患有疾病，也在正常发育过程中表达？发展与发展之间的平行关系病理状态表明，了解 pTau 在发育过程中的功能将阐明 AD 中 tau 病理学的潜在机制。我的初步数据表明 i) 许多 AD 相关 pTau 位点在正常胚胎小鼠大脑中表达，ii) pTau 是可溶的，并且可能在胎儿组织中发挥作用，iii) 位点 T231、S235 和 S262 的磷酸化会损害胎儿 tau 异构体的 MT 聚合，但不会损害成人亚型，和 iv) 这些相同的 pTau 位点加速了成人亚型相对于胎儿亚型的聚集。最近的有证据表明 tau 引发 MT 聚合成核。根据我的初步数据，！认为 tau 磷酸化具有异构体依赖性效应，其中特定的 pTau 位点不利于在衰老的大脑中存在成人亚型，但在发育中的大脑中在胎儿亚型中发挥功能。我将探索两个目标这将为理解每种异构体中 tau 磷酸化的影响提供重要的见解。在目标 1 中，我将确定 pTau 与可溶性微管蛋白和稳定微管蛋白之间的相互作用之间的关系每个异构体中的 MT。在目标 2 中，我将测试导致 tau 解离的 pTau 位点之间的关系来自 MT 与加速其聚集和/或播种活动的 MT。重要的是，我们的实验室拥有独特的合成了在 T231、S235 和 S262 位点具有真正化学磷酸化的全长 tau，用于这些研究。这些实验将使用多个平台进行测试，包括这些化学合成的蛋白质、高分辨率单分子技术（单分子 FRET、荧光相关光谱学和延时 TIRF 显微镜），以及将半合成蛋白质注射到小鼠大脑中。研究人员在处理所描述的生物测定和小鼠模型方面拥有 6 年以上的专业知识在这里，申办者和合作者将指导所描述的化学和生物物理技术的培训。我预计我的发现将阐明 tau 在神经元发育中的功能，并提供对以下问题的深入了解：包括 AD 在内的多种 tau 蛋白病的病理性 tau 蛋白过度磷酸化机制。