Lysosomal Function of Progranulin and Neurodegeneration

颗粒体蛋白前体的溶酶体功能和神经变性

基本信息

批准号：
9913590
负责人：
Fenghua Hu
金额：
$ 48.4万
依托单位：
CORNELL UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2017
资助国家：
美国
起止时间：
2017-08-01 至 2022-05-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/9913590
关键词：
Adenoviruses Affect Alzheimer&apos s Disease Alzheimer&apos s disease model Alzheimer&apos s disease risk Behavioral Binding Biological Assay Brain Cathepsins Cathepsins B Cells Complex Data Defect Dependovirus Disease Disease Progression Enzymes Exhibits Extracellular Space Frontotemporal Lobar Degenerations Functional disorder GRN gene Genes Genetic Transcription Glycoproteins Glycosphingolipids Human Impairment Light Link Lysosomal Storage Diseases Lysosomes Metabolism Molecular Mus Mutation Nerve Degeneration Neurodegenerative Disorders Neuronal Ceroid-Lipofuscinosis Neurons PGRN gene Parkinson Disease Pathologic Pathology Patients Peptide Hydrolases Peptides Phenotype Recombinants Regulation Reporting Role Sampling Saposins Sphingolipids Testing Tissues base human disease insight interdisciplinary approach loss of function lysosomal proteins mutant novel overexpression prevent receptor sortilin tau Proteins therapeutic development trafficking

项目摘要

PROJECT SUMMARY/ABSTRACT Mutations in the Progranulin (PGRN) gene have been linked to two distinct neurodegenerative diseases, frontotemporal lobar degeneration (FTLD) and neuronal ceroid lipofuscinosis (NCL). Accumulating evidence suggests a critical role of PGRN in the lysosome. However how PGRN regulates lysosomal function and protects against neurodegeneration remains elusive. We have identified prosaposin (PSAP), the precursor of saposin peptides essential for lysosomal glycosphingolipid degradation, as a PGRN binding partner. We further showed that PGRN facilitates PSAP lysosomal trafficking from the extracellular space via the neuronal trafficking receptor sortilin. We found reduced neuronal levels of PSAP and saposins in PGRN deficient mice and in FTLD patients due to PGRN mutations. Moreover, we showed that PGRN forms a complex with PSAP and lysosomal proteases cathepsin B and D. Cathepsin D deficiency has been reported to cause FTLD related pathology and our preliminary studies showed that impaired PSAP function also leads to FTLD related phenotypes in mice. Thus we hypothesize that PGRN is critical for proper PSAP and cathepsin B and D functions and impaired PSAP and cathepsin functions is one key disease mechanism of FTLD-PGRN. To test this hypothesis, we propose three specific aims. In Aim1, we will examine the role of PGRN in regulating PSAP function. PSAP trafficking, processing and glycosphingolipid metabolism will be assayed in WT and PGRN-/- cells and tissues as well as control and FTLD-PGRN patient samples. In Aim2, we will determine the role of PGRN in cathepsin B and D trafficking and activation by examining WT and PGRN-/- cells and tissues as well as control and FTLD-PGRN patient samples. In Aim3, we will assay FTLD like phenotypes in mice with different levels of PSAP or cathepsin B or D to determine whether partial loss of PSAP or cathepsin function could contribute to FTLD disease progression. Furthermore, PSAP or cathepsin B or D will be overexpressed via adeno associated viruses (AAV) to determine whether PSAP or cathepsin overexpression can rescue phenotypes associated with PGRN loss in mice. In summary, these proposed studies will shed light on how PGRN regulates lysosomal function and provide novel insights into the disease mechanism of FTLD. We expect the results from our studies to facilitate therapeutic development for FTLD-PGRN as well other neurodegenerative diseases with a reported role of PGRN, such as Alzheimer’s disease.

项目摘要/摘要前植物（PGRN）基因中的突变与两种不同的神经退行性疾病有关，额颞Lobar变性（FTLD）和神经元粘膜脂肪促脂肪肌动病（NCL）。积累证据提出PGRN在溶酶体中的关键作用。但是，PGRN如何调节溶酶体功能和预防神经变性仍然难以捉摸。我们已经确定了Prosaposin（PSAP），这是 Saposin作为PGRN结合伴侣，对溶酶体糖体降解至关重要。我们进一步表明，PGRN的最爱PSAP通过神经元从细胞外空间进行的PSAP溶酶体运输贩运受体分子蛋白。我们发现PGRN缺乏小鼠中PSAP和皂苷的神经元水平降低以及由于PGRN突变引起的FTLD患者。此外，我们表明PGRN与PSAP形成复合物据报道，溶酶体蛋白酶组织蛋白酶B和D.组织蛋白酶D缺乏引起FTLD 相关病理和我们的初步研究表明，PSAP功能受损也会导致FTLD相关小鼠的表型。我们假设PGRN对于适当的PSAP和组织蛋白酶B和D至关重要功能和PSAP和组织蛋白酶功能受损是FTLD-PGRN的关键疾病机制。测试这个假设，我们提出了三个具体目标。在AIM1中，我们将检查PGRN在调节中的作用 PSAP功能。 PSAP贩运，加工和糖磷脂代谢将在WT中分配，并且 PGRN - / - 细胞和组织以及对照和FTLD-PGRN患者样品。在AIM2中，我们将确定 PGRN通过检查WT和PGRN - / - 细胞和组织中PGRN在组织蛋白酶B和D运输和激活中的作用以及对照和FTLD-PGRN患者样品。在AIM3中，我们将在小鼠中像表型相似。具有不同级别的PSAP或组织蛋白酶B或D的水平，以确定PSAP或组织蛋白酶的部分损失功能可能有助于FTLD疾病进展。此外，PSAP或组织蛋白酶B或D将是通过Adeno相关病毒（AAV）过表达，以确定PSAP还是组织蛋白酶过表达是过表达的可以挽救与小鼠PGRN损失相关的表型。总而言之，这些拟议的研究将丢弃阐明PGRN如何调节溶酶体功能并为疾病机制提供新的见解 ftld。我们期望我们的研究结果也可以促进FTLD-PGRN的治疗发展其他具有PGRN作用的神经退行性疾病，例如阿尔茨海默氏病。