Epigenetic Regulation of Ube3a as a Treatment for Angelman Syndrome

描述（由申请人提供）：Angelman综合征（AS）是一种遗传性疾病，其特征为发育迟缓、言语缺失、智力残疾、严重癫痫、共济失调和睡眠异常。AS是由Ube 3a突变或缺失引起的，Ube 3a是一种E3泛素连接酶，在大多数组织中双等位基因表达，但在大脑中单等位基因表达。Ube 3a在大脑中的母体特异性表达被认为是由于在小鼠和人类中产生了超过Ube 3a的父系拷贝的反义转录物。具有Ube 3a母体特异性缺失的小鼠模型具有许多与AS相关的神经发育症状，包括癫痫、学习缺陷和运动异常。使用来自Ube 3a-YFP敲入小鼠的神经元的高通量、无偏筛选，我们鉴定了几种在纳摩尔浓度下使父本Ube 3a等位基因不沉默的小分子。我们假设与Angelman综合征相关的生理和行为功能障碍可以通过使用这些药物之一在体内使父亲的Ube 3a等位基因沉默来治疗。在本提案中，我们将：（1）测试我们的先导化合物在体内上调父本Ube 3a的假设;（2）测试我们的先导化合物可以挽救Angelman综合征模型小鼠中的生理和行为缺陷的假设;（3）测试我们的先导化合物的分子靶的遗传敲除/敲除使父本Ube 3a不沉默的假设;（4）检验Ube 3a正义和Ube 3a反义转录物水平的表达可用作药物功效的生物标志物（即Ube 3a非沉默）的假设。我们的研究可能会导致第一个药物治疗安格尔曼综合征（自闭症谱系障碍），实际上是任何由印记基因突变引起的疾病。

DESCRIPTION (provided by applicant): Angelman syndrome (AS) is a genetic disorder characterized by developmental delay, absent speech, intellectual disability, severe epilepsy, ataxia, and abnormal sleep. AS is caused by mutations in or deletion of Ube3a, an E3 ubiquitin ligase that is expressed biallelically in most tissues but is monoallelically expressed in the brain. Maternal-specific expression of Ube3a in the brain is thought to be due to production of an antisense transcript that overruns the paternal copy of Ube3a in mice and humans. Mice with maternal-specific deletions of Ube3a model many of the neurodevelopmental symptoms associated with AS, including epilepsy, learning deficits, and motor abnormalities. Using a high-throughput, unbiased screen with neurons from a Ube3a- YFP knockin mouse, we identified several small molecules that unsilence the paternal Ube3a allele at nanomolar concentrations. We hypothesize that the physiological and behavioral dysfunctions associated with Angelman syndrome can be treated by unsilencing the paternal Ube3a allele in vivo with one of these drugs. In this proposal we will: (1) Test the hypothesis that our lead compound upregulates paternal Ube3a in vivo; (2) Test the hypothesis that our lead compound can rescue physiological and behavioral deficits in Angelman syndrome model mice; (3) Test the hypothesis that genetic knockdown/out of the molecular target of our lead compound unsilences paternal Ube3a; (4) Test the hypothesis that the expression of the Ube3a-sense and Ube3a-antisense transcript levels can be used as biomarkers of drug efficacy (i.e. Ube3a unsilencing). Our research could lead to the first pharmacological treatment for Angelman syndrome (an autism spectrum disorder), and indeed for any disorder caused by mutation of an imprinted gene.