Regulations of organellar Zn2+ homeostasis and dynamics by TRPML1 in neurons

TRPML1 对神经元细胞器 Zn2 稳态和动力学的调节

基本信息

批准号：
10620676
负责人：
Yan Qin
金额：
$ 32.12万
依托单位：
UNIVERSITY OF DENVER (COLORADO SEMINARY)
依托单位国家：
美国
项目类别：
财政年份：
2019
资助国家：
美国
起止时间：
2019-07-01 至 2025-04-30
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10620676
关键词：
Address Affect Aging Alzheimer&apos s Disease Axonal Transport Biological Biosensor Brain Brain region Cations Cell model Cells Chelating Agents Childhood Cytosol DNA Sequence Alteration Data Detection Disease Dominant-Negative Mutation Engineering Etiology Exhibits Fibroblasts Ganglioside Sialidase Deficiency Disease Genes Goals Health Hela Cells Hippocampus Homeostasis Human Impairment Ions Kinetics Knowledge Lead Lysosomal Storage Diseases Lysosomes Maps Measures Mediating Mental Depression Metals Mitochondria Mitochondrial Matrix Molecular Monitor Mutation Nerve Degeneration Neurites Neurodegenerative Disorders Neurons Organelles Parkinson Disease Pathogenesis Pathologic Patients Permeability Physiological Process Proteins RNA Interference Rattus Regulation Research Role Series Severities Signal Transduction Specificity Testing Time Vesicle Work improved inhibitor injured late endosome nanomolar nervous system disorder neurite growth neurodegenerative phenotype neuronal cell body new therapeutic target next generation novel postsynaptic presynaptic sensor small molecule tool vesicular release

项目摘要

The importance of labile, unbound Zn2+ in normal brain function has been evidenced by the association of abnormal cellular Zn2+ distributions with a series of neurological diseases such as depression, Alzheimer's disease (AD), aging, Mucolipidosis type IV disease (MLIV), and Parkinson’s diseases. MLIV is a lysosomal storage disease with neurodegenerative phenotype developed in childhood. The genetic mutations causing MLIV have been identified in the gene TRPML1, which encodes a lysosomal channel permeable to cations such as Ca2+and Zn2+. Loss of TRPML1 function resulted in elevated lysosomal Zn2+ in the fibroblasts derived from MLIV patients. However, neither the molecular mechanisms nor the biological impacts of such Zn2+ dysregulations are understood. Our preliminary studies devised a novel sensor GZnP3 with unprecedented sensitivity in the nanomolar range and provided the first profound evidence that TRPML1 can mobilize Zn2+ from lysosomes and late endosomes to the cytosol in neurons. Such endolysosomal Zn2+ release is unique in neurons and yields much greater Zn2+ signals in neurites than in the soma. Furthermore, we revealed that nanomolar Zn2+ can reduce the axonal transport in neurons. Based on the preliminary evidence, we hypothesize that impaired Zn2+ release from the vesicular organelles can cause neurodegeneration and contribute to the pathogenesis of MLIV. We will utilize the MLIV cell models along with our unique genetically targeted probes to test our hypothesis and address three specific aims: (1) We will quantify and compare the Zn2+ concentrations among various subcellular compartments in normal and MLIV cell models that are established in human fibroblasts and rat hippocampal neurons; (2) We will utilize our sensitive probes to investigate the correlation between impaired endolysosomal Zn2+ release with MLIV disease and determine the transport mechanisms that concentrate high pools of Zn2+ into endolysosomal vesicles in neurons; (3) We will examine our hypothesis that TRPML1 regulates neuronal health and function by mediating Zn2+ release from lysosomes to the cytosol: the released Zn2+ signals can regulate axonal transport and reduced lysosomal Zn2+ can recover the autophagic function of lysosomes. Collectively, the proposed research will provide ultra sensitive tools for monitoring cellular Zn2+ dynamics, develop a better understanding about the changes in organellar Zn2+ distributions and dynamics in MLIV, characterize the correlation between endolysosomal Zn2+ release and MLIV, as well as reveal the impacts of TRPML1-mediated Zn2+ dynamics on neuronal function. All of the above will significantly expand our knowledge about the pathological mechanisms of MLIV disease.

不稳定，未结合Zn2+在正常脑功能中的重要性已通过异常的细胞Zn2+分布，具有一系列神经系统疾病，例如抑郁症，阿尔茨海默氏症疾病（AD），衰老，粘脂脂病IV疾病（MLIV）和帕金森氏病。 MLIV是溶酶体储存疾病具有童年发展的神经退行性表型。遗传突变引起 MLIV已在基因TRPML1中鉴定出来，该基因编码可渗透到阳离子的溶酶体通道作为Ca2+和Zn2+。 TRPML1功能的丧失导致质合体Zn2+在成纤维细胞中升高 MLIV患者。但是，这种Zn2+的分子机制和生物学影响均未理解失调。我们的初步研究设计了一个新颖的传感器GZNP3 纳摩尔范围内的灵敏度，并提供了第一个深刻的证据，表明TRPML1可以动员Zn2+ 神经元中细胞质的溶酶体和晚期内体。这种内溶性Zn2+释放在神经元中是唯一的与soma中的Zn2+信号更大。此外，我们揭示了纳摩尔 Zn2+可以减少神经元中的轴突运输。根据初步证据，我们假设从囊泡细胞器中释放的Zn2+受损会导致神经变性，并有助于 MLIV的发病机理。我们将利用MLIV细胞模型以及我们独特的遗传靶向问题检验我们的假设并解决三个具体目的：（1）我们将量化和比较Zn2+浓度在正常和MLIV细胞模型中的各种亚细胞隔室中成纤维细胞和大鼠海马神经元；（2）我们将利用我们的敏感问题来研究相关性在患有MLIV疾病的内溶性Zn2+释放受损之间，并确定运输机制将Zn2+的高池集中在神经元中的内溶性蔬菜中；（3）我们将研究我们的假设 TRPML1通过介导Zn2+从溶酶体释放到细胞质来调节神经元健康和功能：释放的Zn2+信号可以调节轴突运输，减少溶酶体Zn2+可以恢复自噬溶酶体的功能。拟议的研究总的来说，将提供超灵敏的工具来监测细胞 Zn2+动力学，对有机Zn2+分布和动态的变化有更好的了解在MLIV中，表征了内溶性Zn2+释放与MLIV之间的相关性，并揭示 TRPML1介导的Zn2+动力学对神经元功能的影响。以上所有这些都将大大扩展我们的有关MLIV疾病的病理机制的知识。