Epigenetic Regulation of Ube3a as a Treatment for Angelman Syndrome

描述(申请人提供)：安杰曼综合征(AS)是一种遗传性疾病，以发育迟缓、言语缺失、智力障碍、严重癫痫、共济失调和睡眠异常为特征。AS是由Ube3a突变或缺失引起的，Ube3a是一种E3泛素连接酶，在大多数组织中双等位表达，但在大脑中单等位表达。母体特有的Ube3a在大脑中的表达被认为是由于在老鼠和人类中产生了一种反义转录，该反义转录超过了父亲的Ube3a拷贝。具有母体特异性Ube3a缺失的小鼠会出现许多与AS相关的神经发育症状，包括癫痫、学习障碍和运动异常。使用来自Ube3a-YFP敲门小鼠的神经元的高通量、无偏见的筛选，我们识别了几个在纳摩尔浓度下解除父亲Ube3a等位基因沉默的小分子。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在体内用这些药物之一解除父亲的Ube3a等位基因沉默来治疗。在这项建议中，我们将：(1)在体内测试我们的先导化合物上调父亲Ube3a的假说；(2)测试我们的先导化合物可以挽救Angelman综合征模型小鼠生理和行为缺陷的假说；(3)测试我们的先导化合物的分子靶点的基因敲除/缺失会使父亲的Ube3a沉默的假说；(4)测试我们的先导化合物Ube3a-正义和Ube3a-反义转录水平可用作药物疗效生物标志物(即Ube3a反义沉默)的假说。我们的研究可能导致第一个治疗Angelman综合症(一种自闭症谱系障碍)的药物治疗，甚至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.