Developmental underpinnings of substantia nigra vulnerability

黑质脆弱性的发育基础

基本信息

批准号：
10558560
负责人：
Rajeshwar B Awatramani
金额：
$ 49.38万
依托单位：
NORTHWESTERN UNIVERSITY AT CHICAGO
依托单位国家：
美国
项目类别：
财政年份：
2021
资助国家：
美国
起止时间：
2021-01-01 至 2025-12-31
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10558560
关键词：
Adult Anatomy Autopsy Axon Bioenergetics Cells Characteristics Classification Corpus striatum structure Data Dendrites Development Disease Disease model Dopamine Dorsal Electron Transport Pathway Embryo Embryonic Development Endowment Event Floor Foundations Gene Expression Genes Genetic Transcription Goals Human Label Laboratories Lateral Link Locomotion Maps Medial Midbrain structure Mitochondria Modeling Molecular Morphology Nerve Degeneration Neural tube Neuroanatomy Neurons Oxidative Phosphorylation Parkinson Disease Physiological Physiology Population Production Property Recording of previous events Resistance SOX6 gene Sampling Signal Transduction Substantia nigra structure Techniques Testing Toxin Translating Transplantation Variant Ventral Tegmental Area Work cohort dopaminergic neuron genetic approach insight motor symptom neurogenesis neuron development neuronal survival novel oxidant stress pars compacta progenitor release of sequestered calcium ion into cytoplasm single-cell RNA sequencing tool transcription factor transcriptome transcriptomics

项目摘要

Abstract: DA neuron degeneration, resulting in deficient DA signaling, underpins the debilitating motor symptoms of Parkinson’s disease (PD). Among DA neurons, those located in ventral tier of the substantia nigra pars compacta (SNc), are particularly vulnerable, compared to those in the dorsal tier of the SNc or ventral tegmental area (VTA). A mechanistic explanation of selective DA neuron vulnerability remains an important goal, that has been hampered in part by a lack of understanding of the intrinsic differences between DA neurons. We hypothesize that even within a single neuroanatomical cluster like the SNc, there exist DA subtypes with distinct developmental histories and intrinsic properties that may influence their vulnerability. Single cell expression profiling based DA neuron classification from our lab revealed the presence of a key SNc population defined by Sox6 and Aldh1a1 - this subtype was located in the ventral tier of the SNc, and was preferentially vulnerable in a toxin model of PD. Our preliminary data indicate that this population exists in human SNc, and is also selectively vulnerable in post-mortem PD samples. To interrogate the basis for selectively vulnerability in the SNc in depth, we next developed a set of intersectional genetic strategies, which strikingly defined a fault-line in the SNc defined by Sox6 expression, with Sox6+ cells being located ventrally and Sox6- cells forming the dorsal tier. Building on these studies, several key questions remain unanswered. Are dorsal and ventral SNc subtypes developmentally distinct? Do these neurons have different anatomical features and DA release characteristics? Is the size of arborizations of these neurons, a property linked to vulnerability, different? Are calcium fluxes and mitochondrial bioenergetic properties distinct? To answer these questions, in Aim 1, we will determine the origin of SNc neuron subtypes. We will use intersectional, subtractive, and inducible genetic approaches, as well as a novel progenitor anchored fate mapping approach (PRISM) to test the hypothesis that the dorsal and ventral tier DA neurons are developmentally distinguished by Sox6. We will then test the potential of Sox6+ medial vs Sox6- lateral floor plate progenitors to give rise to SNc neurons when transplanted into a PD model. In Aim 2, we will examine the arborization of genetically defined SNc neurons, since this feature has been linked to their vulnerability. Using a new sparse labeling tool, we will plot the projections of genetically defined SNc DA neuron subtypes, and determine the size of their arbors, and explore the molecular determinants of extensive arborization. We will also study DA release from axons and dendrites to determine if dorsal and ventral tier neurons are distinguishable by these criteria, also linked to vulnerability. In Aim 3, we will test the hypothesis that the SNc DA neuron subtypes have distinctive physiological properties and that these differences translate into differences in mitochondrial oxidant stress in somatodendritic and axonal compartments. Overall, our studies redefining the SNc based on lineage will provide important insights into selective vulnerability.

摘要：DA 神经元变性导致 DA 信号传导缺陷，导致运动能力衰弱帕金森病 (PD) 的症状位于黑质腹侧的 DA 神经元中。与 SNc 背层或腹侧的致密部 (SNc) 相比，特别脆弱选择性 DA 神经元脆弱性的机制解释仍然是重要的。由于缺乏对 DA 神经元之间内在差异的了解，这一目标的实现在一定程度上受到了阻碍。我们发现，即使在像 SNc 这样的单个神经解剖簇内，也存在 DA 具有不同发展历史和可能影响其脆弱性的内在特性的亚型。我们实验室基于单细胞表达谱的 DA 神经元分类揭示了关键的存在由 Sox6 和 Aldh1a1 定义的 SNc 群体 - 该亚型位于 SNc 的腹侧层，并且是我们的初步数据表明，该人群存在于 PD 毒素模型中。人类 SNc，并且在死后 PD 样本中也选择性易受攻击，以询问其基础。为了深入研究 SNc 的选择性脆弱性，我们接下来开发了一套交叉遗传策略，显着地定义了由 Sox6 表达定义的 SNc 断层线，Sox6+ 细胞位于腹侧形成背层的 Sox6- 细胞在这些研究的基础上，几个关键问题仍未得到解答。背侧和腹侧 SNc 亚型在发育上是否不同？这些神经元具有不同的解剖结构吗？这些神经元的树状结构的大小与 DA 释放特性有关吗？脆弱性，不同吗？钙通量和线粒体生物能特性不同吗？为了回答这些问题，在目标 1 中，我们将使用 SNc 神经元亚型的起源。交叉、消减和诱导遗传方法，以及一种新的祖锚定命运映射方法（PRISM）来检验背侧和腹侧 DA 神经元的假设然后我们将测试 Sox6+ 内侧地板与 Sox6- 外侧地板的潜力。当移植到 PD 模型中时，板祖细胞会产生 SNc 神经元。在目标 2 中，我们将检查遗传定义的 SNc 神经元的树状化，因为这一特征与它们的脆弱性有关。一个新的稀疏标记工具，我们将绘制基因定义的 SNc DA 神经元亚型的投影，以及确定其乔木的大小，并探索广泛乔木化的分子决定因素。还研究轴突和树突的 DA 释放，以确定背侧和腹侧层神经元是否通过这些标准可以区分，也与脆弱性相关。在目标 3 中，我们将检验 SNc 的假设。 DA 神经元亚型具有独特的生理特性，这些差异转化为总体而言，我们的研究表明体细胞树突和轴突区室中线粒体氧化应激的差异。基于谱系重新定义 SNc 将为选择性脆弱性提供重要的见解。