The Role of Sensory Receptors in Angelman Syndrome

感觉感受器在天使综合症中的作用

• 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
• 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

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.

Angelman综合征（AS）是一种以智力障碍和非典型行为为特征的神经遗传性疾病。 AS是由来自母体等位基因的E3泛素蛋白连接酶（UBE3A）表达缺失引起的。的 UBE3A基因是父系印记的（即，抑制）在人类和小鼠的大多数神经元中。删除，突变， 或母源等位基因表达缺失导致AS。AS患者的运动协调能力受损 (e.g.,不能到达物体），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。治疗这种疾病的一个关键障碍是， 引起AS步态缺陷的机制尚不清楚。本体感受赋予了感知的能力 运动、平衡和肢体位置。机械敏感性离子通道PIEZO 2在感觉神经元中表达。 神经元支配肌梭和高尔基腱器官，在那里它介导本体感觉，步态， 平衡缺乏PIEZO 2表达的小鼠和人具有不稳定的步态，步幅增加， 步长变化和姿势缺陷。这些研究的基本原理依赖于来自人类的证据。 遗传学和小鼠模型表明，具有AS或PIEZO 2功能丧失突变的个体可能共享 机械感觉缺陷我们的假设是AS相关的步态缺陷源于PIEZO 2减少 在感觉神经元中起作用。我们的初步数据支持我们的假设，因为它表明PIEZO 2电流 在Ube3a缺陷的小鼠神经元、UBE3A敲低的人细胞和干细胞衍生的 来自AS患者的神经元。没有可用于增加PIEZO 2活性的激动剂。的分子 增强PIEZO 2功能可以绕过与UBE 3A表达丧失相关的机械缺陷。 我们确定富含亚油酸（LA）的红花油饮食增加PIEZO 2电流和机械电流。 兴奋性，以及改善AS小鼠的步态。同样地，LA补充增强了PIEZO 2的功能， 干细胞来源的神经元从个人与AS。我们的总体目标是通过以下方式确定机制： 其中UBE3A表达的丧失降低PIEZO 2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、生物化学、生物物理学和行为分析， 详细了解UBE 3A和PIEZO 2对AS的贡献。我们将采取三项具体措施 目的：1）确定UBE 3A表达缺失降低PIEZO 2电流的机制，2） 确定LA增加PIEZO 2活性的机制，以及3）检验LA 通过PIEZO 2改善AS的步态缺陷。这项研究意义重大，因为它有望 提供了一个详细的了解分子机制，占减少PIEZO 2电流， AS和富含LA的膜在增加PIEZO 2功能中的作用。