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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.

不稳定的、未结合的Zn 2+在正常脑功能中的重要性已经通过以下关联得到证明：细胞内Zn ~（2+）分布异常与抑郁症、阿尔茨海默病等一系列神经系统疾病有关疾病（AD）、衰老、IV型粘脂沉积病（MLIV）和帕金森病。MLIV是一种溶酶体在儿童时期发展的具有神经变性表型的胆积病。基因突变导致 MLIV已经在基因TRPML 1中被鉴定，该基因编码可渗透阳离子的溶酶体通道， Ca 2+和Zn 2+。TRPML 1功能的丧失导致来源于成纤维细胞的溶酶体Zn 2+升高， MLIV患者。然而，无论是分子机制还是这种Zn 2+的生物学影响，失调可以理解。我们的初步研究设计了一种新的传感器GZnP 3，在纳摩尔范围内的灵敏度，并提供了第一个深刻的证据，TRPML 1可以动员Zn 2+从溶酶体和晚期内体到神经元中的胞质溶胶。这种内溶酶体Zn 2+释放在神经元中是独特的并且在神经突中产生比在索马中大得多的Zn 2+信号。此外，我们发现纳摩尔 Zn ~（2+）可使神经元轴突运输减少。基于初步证据，我们假设从泡状细胞器中释放的受损的Zn 2+可引起神经变性，并有助于 MLIV的发病机制。我们将利用MLIV细胞模型沿着我们独特的遗传靶向探针，测试我们的假设，并解决三个具体目标：（1）我们将量化和比较Zn 2+浓度在人类中建立的正常和MLIV细胞模型的各种亚细胞区室中，成纤维细胞和大鼠海马神经元;（2）我们将利用我们的敏感探针来研究相关性内溶酶体锌离子释放受损与MLIV疾病之间的关系，并确定将高浓度的Zn 2+集中到神经元的内溶酶体囊泡中;（3）我们将检验我们的假设， TRPML 1通过介导Zn 2+从溶酶体释放到胞质溶胶来调节神经元的健康和功能：释放的Zn ~（2+）信号可以调节轴突运输，减少的溶酶体Zn ~（2+）可以恢复自噬 lysosomes的功能总的来说，拟议的研究将提供超灵敏的工具，用于监测细胞 Zn 2+动力学，更好地了解细胞器Zn 2+分布和动力学的变化在MLIV中，表征内溶酶体Zn 2+释放与MLIV之间的相关性，并揭示 TRPML 1介导的Zn 2+动力学对神经元功能的影响。所有这些都将大大扩大我们的了解MLIV疾病的病理机制。