Microglial regulation of Progranulin levels

小胶质细胞对颗粒体蛋白前体水平的调节

基本信息

批准号：
10347312
负责人：
Janghoo Lim
金额：
$ 62.32万
依托单位：
YALE UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2020
资助国家：
美国
起止时间：
2020-02-01 至 2024-12-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10347312
关键词：
Adult Affect Alzheimer&apos s Disease Alzheimer&apos s disease related dementia Alzheimer&apos s disease risk Behavioral Behavioral Assay Biochemical Biology Brain CRISPR/Cas technology Cell Culture System DNA Sequence Alteration Data Dementia Development Disease Endocytosis Frontotemporal Lobar Degenerations Future Genetic Glycoproteins Goals Grant Homologous Gene Human Knockout Mice Knowledge Lead Link Mediating Microglia Molecular Molecular Target Mus Mutation Nervous System Physiology Neurodegenerative Disorders Neuronal Ceroid-Lipofuscinosis Onset of illness PGRN gene Pathologic Pathology Pathway interactions Patients Phenotype Phosphotransferases Plasma Protein-Serine-Threonine Kinases Proteins Proteomics Regulation Research Role Single Nucleotide Polymorphism Symptoms Testing Therapeutic Intervention Validation base behavioral phenotyping dosage efficacy testing granulin human disease improved in vivo induced pluripotent stem cell insight loss of function mouse genetics nemo-like kinase nervous system disorder neuropathology novel therapeutic intervention overexpression patient subsets prevent receptor targeted treatment therapeutic development therapeutically effective trafficking

项目摘要

Genetic mutations in Granulin (GRN) that result in reduced levels of its encoded protein, progranulin (PGRN), have been implicated in several distinct neurological disorders, depending on the degree of PGRN reduction. More specifically, haploinsufficiency resulting from heterozygous GRN mutations has been identified to be causal for a subset of patients with frontotemporal lobar degeneration (FTLD), an adult-onset neurodegenerative disease. Furthermore, homozygous loss-of-function GRN mutations result in neuronal ceroid lipofuscinosis (NCL), and single nucleotide variants that decrease plasma and brain PGRN levels are risk factors for Alzheimer’s Disease (AD). The clear association between reduced levels of PGRN and neurological disorders highlights the importance of adequate PGRN dosage in normal nervous system function. The overarching goal of this project is to better understand the precise cellular and molecular mechanisms that are involved in the regulation of PGRN. In order to reach this goal, we began by identifying factors that could potentially modulate phenotypes associated with PGRN haploinsufficiency. The preliminary data presented in this application clearly show that Nemo-like kinase (NLK), an evolutionarily conserved serine/threonine kinase, is involved in the regulation of PGRN levels and can modulate phenotypes associated with PGRN reduction in vivo through microglia. To investigate this idea further, we propose the following three specific aims. In Specific Aim 1, we will determine whether altering Nlk levels specifically in microglia can modulate FTLD-related phenotypes in vivo using mouse genetics. Specifically, (1) we will first test whether constitutive loss of Nlk in microglia is able to induce FTLD-related neuropathological and behavioral phenotypes. (2) Conversely, we will examine if constitutive overexpression of Nlk in microglia can prevent or ameliorate these same phenotypes. We will focus on neuropathological changes and behavioral deficits that have been previously ascribed to PGRN reduction in FTLD-PGRN patients and Grn knockout mice. In Specific Aim 2, we will elucidate the molecular mechanism through which Nlk regulates Pgrn levels in microglia. We will (1) employ mouse genetics and isogenic human induced pluripotent stem cell-derived microglia to determine the receptor involved in Nlk-mediated regulation of Pgrn endocytosis and (2) utilize unbiased proteomics approaches to identify direct molecular targets of Nlk that function in this regulation. In Specific Aim 3, we will determine whether GRN-associated neuropathology can be suppressed or reversed by increasing Nlk expression in adulthood. To do this, we will temporally induce the overexpression of Nlk after disease onset and test the efficacy in ameliorating or reversing pathological and behavioral deficits. We believe that the knowledge gained from the studies proposed in this application will advance our basic understanding of the cellular and mechanism underlying PGRN regulation and will suggest new therapeutic interventions aimed at reducing the burden of FTLD and other neurological disorders associated with PGRN reduction such as AD.

颗粒体蛋白 (GRN) 的基因突变导致其编码蛋白颗粒体蛋白前体 (PGRN) 的水平降低，与几种不同的神经系统疾病有关，具体取决于 PGRN 减少的程度。更具体地说，杂合 GRN 突变导致的单倍体不足已被确定为导致部分额颞叶变性 (FTLD) 患者的病因，这是一种成人发病的疾病此外，纯合性 GRN 功能丧失突变会导致神经元退化。蜡质脂褐质沉着症 (NCL)，以及降低血浆和脑 PGRN 水平的单核苷酸变异 PGRN 水平降低与阿尔茨海默病 (AD) 的危险因素之间存在明显关联。神经系统疾病凸显了正常神经系统中充足的 PGRN 剂量的重要性该项目的总体目标是更好地了解精确的细胞和分子功能。为了实现这一目标，我们首先确定了参与 PGRN 调节的机制。可能调节与 PGRN 单倍体不足相关的表型的因素。本申请中提供的数据清楚地表明 Nemo 样激酶 (NLK)，一种进化上保守的激酶丝氨酸/苏氨酸激酶，参与 PGRN 水平的调节，并可调节相关表型为了进一步研究这个想法，我们提出了以下三个建议。在具体目标 1 中，我们将确定是否可以专门改变小胶质细胞中的 Nlk 水平。使用小鼠遗传学在体内调节 FTLD 相关表型具体来说，(1) 我们将首先测试是否。小胶质细胞中 Nlk 的组成性缺失能够诱发 FTLD 相关的神经病理学和行为学 (2)离线时，我们将检查小胶质细胞中Nlk的组成型过度表达是否可以预防或改善这些相同的表型，我们将重点关注神经病理学变化和缺陷。先前已将其归因于 FTLD-PGRN 患者和 Grn 基因敲除小鼠的 PGRN 减少。目标 2，我们将阐明 Nlk 调节小胶质细胞 Pgrn 水平的分子机制。 (1)利用小鼠遗传学和同基因人类诱导多能干细胞来源的小胶质细胞来确定参与 Nlk 介导的 Pgrn 内吞作用调节的受体，以及 (2) 利用无偏蛋白质组学在具体目标 3 中，我们将采用多种方法来识别在该调节中发挥作用的 Nlk 直接分子靶点。确定是否可以通过增加 Nlk 来抑制或逆转 GRN 相关的神经病理学为此，我们将在疾病发作后暂时诱导 Nlk 的过度表达。并测试改善或逆转病理和行为缺陷的功效。从本申请中提出的研究中获得的知识将增进我们对 PGRN 调节的细胞和机制，并将提出新的治疗干预措施减轻 FTLD 和其他与 PGRN 减少相关的神经系统疾病（例如 AD）的负担。