Epigenetic Regulation of Ube3a as a Treatment for Angelman Syndrome

描述（由申请人提供）：Angelman综合征（AS）是一种以发育迟缓、语言障碍、智力障碍、严重癫痫、共济失调和睡眠异常为特征的遗传性疾病。AS是由Ube3a突变或缺失引起的，Ube3a是一种E3泛素连接酶，在大多数组织中以双等位基因表达，但在大脑中以单等位基因表达。在小鼠和人类中，Ube3a的母体特异性表达被认为是由于产生了一种反义转录物，该转录物超过了Ube3a的父本拷贝。母鼠特异性缺失Ube3a基因的小鼠产生了许多与AS相关的神经发育症状，包括癫痫、学习缺陷和运动异常。利用来自Ube3a- YFP敲入小鼠的神经元进行高通量、无偏筛选，我们发现了几个小分子，这些小分子可以在纳摩尔浓度下解除父本Ube3a等位基因的沉默。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其中一种药物在体内解除父本Ube3a等位基因的沉默来治疗。在本研究中，我们将：(1)在体内验证先导化合物上调父系Ube3a的假设；(2)验证先导化合物对Angelman综合征模型小鼠生理和行为缺陷的修复作用；(3)验证先导化合物分子靶点基因敲低/敲出导致父系Ube3a沉默的假设；(4)验证Ube3a-sense和Ube3a-反义转录物表达水平可作为药物疗效（即Ube3a解沉默）的生物标志物的假设。我们的研究可能会导致Angelman综合征（一种自闭症谱系障碍）的第一个药物治疗，以及任何由印迹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.