Mitochondrial Calcium and Neuronal Health

线粒体钙和神经元健康

基本信息

批准号：
10638869
负责人：
Gyorgy Hajnoczky
金额：
$ 61.65万
依托单位：
THOMAS JEFFERSON UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2023
资助国家：
美国
起止时间：
2023-06-15 至 2028-05-31
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10638869
关键词：
3-Dimensional Acute Adult Affect Animals Antioxidants Architecture Area Behavioral Biochemistry Birth Brain Brain Hypoxia Brain Injuries Calcium Calcium Signaling Cell Death Cells Chemicals Complex Corpus striatum structure Cytoplasm Data Dendritic Spines Dependence Development Disease Down-Regulation Electron Microscopy Etiology Exposure to Fibroblasts Fluorescence Fluorescent Dyes Functional Imaging Gatekeeping Genetic Genetic Models Glutathione Disulfide Health Health system Hepatocyte Hippocampus Homeostasis Human Hydrogen Peroxide Hypoxia Image Impaired cognition Impairment Inherited Injury Ischemia Knockout Mice Learning Life Link Mammals Measures Mediating Membrane Microscopy Mitochondria Molecular Morphology Motor Motor Cortex Mus Nerve Degeneration Nervous System Nervous System Physiology Neuroanatomy Neurologic Neuronal Injury Neurons Neurosecretion Outcome Outer Mitochondrial Membrane Oxidants Pathogenesis Pathogenicity Patients Peptide Hydrolases Permeability Phenotype Physiological Physiology Positioning Attribute Presynaptic Terminals Process Production Protein Isoforms Proteins Regulation Reperfusion Injury Reperfusion Therapy Reporter Reporting Resolution Role Shapes Signal Transduction Spinal Cord Stains Stress Stroke Structure Synapses Synaptic Vesicles Testing Work behavior test calcium uniporter cell injury dimer falls fluorescence imaging in vivo inhibitor loss of function motor disorder motor impairment mouse model multi-photon nervous system disorder neuropathology new therapeutic target paralogous gene prevent protective effect recruit scaffold sensor targeted treatment ultra high resolution uptake vesicular release

项目摘要

ABSTRACT Propagation of calcium (Ca2+) signals to the mitochondria through the Ca2+ uniporter has long been considered central to neuronal function. The discovery of the molecular components of the uniporter including the Ca2+ sensing regulator MICU1, was followed by the identification of many MICU1 loss-of-function patients who display progressive neurological disorder, dominated by motor and learning impairments, which were recapitulated in mouse models created by us and others. Emerging evidence indicates that acute MICU1 proteolytic degradation by YME1L also occurs during hypoxia, suggesting that dysregulation of mitochondrial Ca2+ homeostasis may also play a role in ischemia/stroke. However, the neuronal pathogenesis associated with MICU1 deficiency and, more broadly, the role of uniporter regulation in healthy neurons, remain poorly understood. MICU1 forms dimers with its paralogs, MICU2 and MICU3, and with itself. MICU2 has also been linked to human neurological impairments but is scarce in adult neurons, whereas MICU3 is abundant in adult brain. Our central hypothesis is that control of mitochondrial Ca2+ uptake by MICU1/2/3 is essential for coordinating mitochondrial function with synaptic activity. This control also prevents mitochondrial Ca2+ overload and oxidant dysregulation that lead to neuronal stress. Further, we postulate dynamic tuning of neuronal MICU-dependent gatekeeping: during development—by a switch from primarily MICU1-MICU2 to MICU1-MICU3 dimers during early life—and under hypoxic stress, by specific proteolytic degradation of MICU1, with potentially pathogenic consequences. To test these ideas, we will use a neuron-specific MICU1 knockout mouse which we found to display neurodegeneration characterized by mitochondrial Ca2+ overload, altered mitochondrial and neuronal ultrastructure, and motor and cognitive impairments. We have also generated mice with MICU2 and MICU3 loss and have obtained MICU1 and MICU2 patient-derived cells. We have set up advanced functional imaging and large volume 3D ultrastructure capacities. Thus, we are well positioned to study the neuronal pathogenesis associated with the loss of each or multiple MICU isoforms. In Aim#1 we will test the hypothesis that neurons derived from MICU1, MICU2 or MICU3-deficient mice and MICU1 and MICU2-deficient patient fibroblast-derived neurons have distinct impairments in Ca2+ signaling, mitochondrial dynamics and synaptic vesicle release. In Aim#2 we will test if neuronal MICU1/2/3 loss promotes mitochondrial oxidant production and oxidant-mediated cell injury. The results will help to decide if oxidants are relevant to MICU-linked neuronal/brain injury. In Aim#3 we will test the hypothesis that the relative abundance of the different MICU isoforms is dynamic in neurons during development, and the loss of each isoform specifically affects neuroanatomy and brain function primarily in the motor areas and the hippocampus. In Aim#4 we will test if ischemia-reperfusion induces YME1L-mediated turnover of MICU1 to promote mitochondrial Ca2+ overload injury and to sensitize the uniporter to inhibitors. These studies are expected to decide if MICU1 loss is a pathogenic component and therapy-modifying factor in brain hypoxia.

抽象的长期以来一直认为，通过Ca2+ unit蛋白向线粒体传播钙（Ca2+）信号已被考虑神经元功能的中心。发现包括Ca2+的分子成分的发现传感调节剂MICU1之后，鉴定出许多显示功能丧失患者进行性神经系统障碍，由运动和学习障碍主导，这些障碍在鼠标模型由我们和其他人创建。新兴证据表明急性MICU1蛋白水解降解由YME1L也发生在缺氧期间，表明线粒体Ca2+稳态的失调可能还可以在缺血/中风中发挥作用。然而，与MICU1缺乏症相关的神经元发病机理以及从更广泛的角度来看，统一调节在健康神经元中的作用仍然知之甚少。 MICU1形成二聚体伴随旁系同源物，Micu2和Micu3，并与其本身。 MICU2也与人类神经系统有关损伤但在成年神经元中稀少，而成人大脑中的MICU3丰富。我们的中心假设 MICU1/2/3对线粒体Ca2+摄取的控制对于与线粒体函数的协调至关重要突触活动。该控件还可以防止线粒体Ca2+过载和氧化剂失调导致神经元应力。此外，我们假设神经元素依赖性守门的动态调整：开发 - 从初级的MICU1-MICU2转换为早期的MICU1-MICU3二聚体 - 低氧应激，通过MICU1的特异性蛋白水解降解，并具有潜在的致病性后果。测试这些想法，我们将使用一种神经特异性的MICU1敲除鼠标，我们发现它显示神经变性以线粒体Ca2+过载的特征，线粒体和神经元超微结构的改变，运动以及认知障碍。我们还产生了MICU2和MICU3损失的小鼠，并获得了MICU1 和MICU2患者衍生的细胞。我们已经建立了高级功能成像和大卷3D 超微结构能力。这，我们可以很好地研究与每种或多个MICU同工型的损失。在AIM＃1中，我们将检验以下假设，即源自MICU1的神经元， MICU2或MICU3缺乏小鼠以及MICU1和MICU2缺乏患者成纤维细胞衍生的神经元具有不同的 Ca2+信号传导，线粒体动力学和突触囊泡释放的损伤。在AIM＃2中，我们将测试是否神经元MICU1/2/3损失促进了线粒体氧化剂的产生和氧化剂介导的细胞损伤。这结果将有助于确定氧化剂是否与MICU连接的神经元/脑损伤有关。在AIM＃3中，我们将测试假设不同MICU同工型的相对丰度在发育过程中的神经元中是动态的，每种同工型的丧失特异性影响运动区域的神经解剖学和脑功能主要和海马。在AIM＃4中，我们将测试缺血 - 重新灌注是否诱导MICU1的YME1L介导的营业额促进线粒体Ca2+超负荷损伤，并感知到抑制剂的单位。这些研究是预计将确定MICU1损失是否是脑缺氧中的致病成分和治疗改良因子。