The Role of Sensory Receptors in Angelman Syndrome

感觉感受器在天使综合症中的作用

基本信息

批准号：
10630683
负责人：
Julio F Cordero-Morales
金额：
$ 51.21万
依托单位：
UNIVERSITY OF TENNESSEE HEALTH SCI CTR
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：
2023-02-15 至 2023-08-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10630683
关键词：
Acids Actin-Binding Protein Actins Action Potentials Afferent Neurons Agonist Alleles Angelman Syndrome Animals Atomic Force Microscopy Behavior Behavioral Biochemical Biochemistry Biophysics Brain Bypass Cell membrane Cells Chemicals Cytoskeleton Data Diet Disease Electrophysiology (science)Endowment Equilibrium Evaluation F-Actin Gait Gait abnormality Genetic Models Goals Golgi Tendon Organs Human Human Cell Line Human Genetics Individual Intellectual functioning disability Intervention Ion Channel Knockout Mice Knowledge Length Ligase Limb structure Linoleic Acids Lipids Measures Mechanics Mediating Membrane Microfilaments Mission Molecular Movement Mus Muscle Spindles Mutation Neurons Piezo 2 ion channel Polyunsaturated Fatty Acids Positioning Attribute Posture Property Proprioception Proteins Public Health Repression Research Role Safflower Oil Seizures Sensory Sensory Ataxias Sensory Receptors Specificity Spectrin Spinal Ganglia Supplementation Testing UBE3A gene United States National Institutes of Health Unsteady Gait Walking Wheelchairs Work cofilin conditional knockout feeding improved in vivo knock-down lipidomics loss of function loss of function mutation motor impairment mouse model neurogenetics optogenetics paternal imprint stem cells ubiquitin-protein ligase walker

项目摘要

Angelman syndrome (AS) is a neurogenetic disorder characterized by intellectual disability and atypical behavior. AS results from a loss of expression of the E3 ubiquitin-protein ligase (UBE3A) from the maternal allele. The UBE3A gene is paternally imprinted (i.e., repressed) in most neurons of humans and mice. Deletion, mutation, or loss of expression of the maternal allele results in AS. Individuals with AS display impaired motor coordination (e.g., inability to reach objects), gait deficits (i.e., instability while walking), and seizures. There are no interventions for ameliorating gait deficits. A critical barrier for treating this condition is that the molecular mechanisms that give rise to gait deficits in AS are unknown. Proprioception confers the ability to sense movement, balance, and limb position. The mechanosensitive ion channel PIEZO2 is expressed in sensory neurons innervating muscle spindles and Golgi tendon organs, where it mediates proprioception, gait, and balance. Mice and humans lacking PIEZO2 expression have an unsteady gait, increased stride-to-stride variability in step length, and postural deficits. The rationale for these studies relies on the evidence from human genetics and mouse models suggesting that individuals with AS or PIEZO2 loss-of-function mutations may share mechanosensation deficits. Our hypothesis is that AS-associated gait deficits originate from reduced PIEZO2 function in sensory neurons. Our preliminary data support our hypothesis because it shows that PIEZO2 currents are reduced in Ube3a-deficient mouse neurons, human cells with UBE3A knock-down, and stem cell-derived neurons from individuals with AS. There are no available agonists to increase PIEZO2 activity. Molecules that enhance PIEZO2 function could bypass the mechanical deficits associated with the loss of UBE3A expression. We determined that a safflower oil diet, enriched in linoleic acid (LA), increases PIEZO2 currents and mechanical excitability, as well as improves gait in AS mice. Likewise, LA supplementation enhances PIEZO2 function in stem cell-derived neurons from individuals with AS. Our overall objective is to determine the mechanisms by which loss of UBE3A expression decreases PIEZO2 currents (and/or expression) and LA recovers channel function. To this end, we will carry out electrophysiological, biochemical, biophysical, and behavioral analyses to provide a detailed understanding of the contribution of UBE3A and PIEZO2 to AS. We will pursue three Specific Aims: 1) Determine the mechanism whereby loss of UBE3A expression decreases PIEZO2 currents, 2) Determine the mechanism by which LA increases PIEZO2 activity, and 3) Test the hypothesis that LA ameliorates gait deficits in AS through PIEZO2. The proposed research is significant because it is expected to provide a detailed understanding of the molecular mechanisms that accounts for diminished PIEZO2 currents in AS and the role of LA-enriched membranes in increasing PIEZO2 function.

安杰曼综合症（AS）是一种神经遗传性疾病，其特征是智力障碍和非典型行为。 AS 是由于母体等位基因 E3 泛素蛋白连接酶 (UBE3A) 表达缺失所致。这 UBE3A 基因在人类和小鼠的大多数神经元中具有父系印记（即抑制）。缺失、突变、或母体等位基因表达缺失导致 AS。 AS 患者的运动协调能力受损（例如，无法够到物体）、步态缺陷（即行走时不稳定）和癫痫发作。没有改善步态缺陷的干预措施。治疗这种疾病的一个关键障碍是分子引起 AS 步态缺陷的机制尚不清楚。本体感觉赋予感知能力运动、平衡和肢体位置。机械敏感离子通道 PIEZO2 以感觉表达神经元支配肌梭和高尔基腱器官，介导本体感觉、步态和平衡。缺乏 PIEZO2 表达的小鼠和人类步态不稳定，步幅增加步长的变化和姿势缺陷。这些研究的基本原理依赖于人类的证据遗传学和小鼠模型表明，携带 AS 或 PIEZO2 功能丧失突变的个体可能具有以下共同特征：机械感觉缺陷。我们的假设是 AS 相关的步态缺陷源于 PIEZO2 减少在感觉神经元中发挥作用。我们的初步数据支持我们的假设，因为它表明 PIEZO2 电流在 Ube3a 缺陷的小鼠神经元、UBE3A 敲低的人类细胞和干细胞来源的细胞中减少来自 AS 个体的神经元。没有可用的激动剂来增加 PIEZO2 活性。分子增强 PIEZO2 功能可以绕过与 UBE3A 表达缺失相关的机械缺陷。我们确定富含亚油酸 (LA) 的红花油饮食可增加 PIEZO2 电流和机械强度兴奋性，并改善 AS 小鼠的步态。同样，LA 补充剂可增强 PIEZO2 功能来自 AS 个体的干细胞来源的神经元。我们的总体目标是通过以下方式确定机制： UBE3A 表达缺失会降低 PIEZO2 电流（和/或表达）并且 LA 恢复通道功能。为此，我们将进行电生理学、生化、生物物理和行为分析，以详细了解UBE3A和PIEZO2对AS的贡献。我们将追求三个具体目标目标：1) 确定 UBE3A 表达缺失导致 PIEZO2 电流降低的机制，2) 确定 LA 增加 PIEZO2 活性的机制，并且 3) 检验 LA 的假设通过 PIEZO2 改善 AS 的步态缺陷。拟议的研究意义重大，因为预计提供对导致 PIEZO2 电流减少的分子机制的详细了解 AS 和富含 LA 的膜在增强 PIEZO2 功能中的作用。