Control of long gene expression as a novel therapeutic approach for Rett syndrome

项目总结： Rett综合征是导致女孩智力残疾的最常见的遗传原因，其特点是 神经发育迟缓、手臂运动异常、癫痫发作和自闭症谱系行为。一直以来 人们知道Rett综合征是由MECP2基因突变引起的，并在近十年后恢复 啮齿动物模型中正常水平的MECP2，即使在症状出现后，也可以逆转大多数症状。虽然这件事 基因洞察力为治疗提供了希望，神经元中令人难以置信的MeCP2功能的复杂性 挑战了可操作的治疗策略的发展。已知的MeCP2高度富含 神经元和与甲基化的DNA结合，但它对转录的微妙影响一直难以理解和 与Rett综合征表型的严重程度一致。我们实验室最近进行了一项荟萃分析 对MeCP2调节的基因进行了近12项独立研究，发现MeCP2选择性地控制 超长基因的表达。这种观察是MeCP2高度特异的，并且在两种啮齿动物中都观察到了 模型和Rett综合征患者。神经元中MeCP2的高水平及神经元蛋白的变化趋势 体型较大，由长基因编码，这可能解释了为什么MeCP2突变优先导致神经元 功能障碍。我们的初步数据支持长基因错误调控在Rett发病机制中的作用 直接使用拓扑异构酶抑制剂使长基因表达正常化可改善Rett的综合征 体外和体内的表型。在神经元中，拓扑异构酶的功能是在转录过程中解开DNA，并 是表达长基因所必需的。MeCP2和MeCP2对长基因表达的相互调控 拓扑异构酶，以及证明这些蛋白质之间存在物理相互作用的初步数据，提高了 几个重要的机制和治疗相关的问题，是这项建议的重点。1)至 拓扑异构酶抑制对小鼠视网膜色素变性模型的细胞和行为的影响 2)研究MeCP2与拓扑异构酶的相互作用。加在一起，这些 研究旨在为Rett综合征提供一种新的治疗策略，重点是纠正长基因调控错误 通过直接控制拓扑异构酶活性。

PROJECT SUMMARY: Rett syndrome is the most common genetic cause of intellectual disability in girls and is characterized by neurodevelopmental delay, abnormal arm movements, seizures, and autism spectrum behavior. It has been known for nearly a decade that Rett syndrome is caused by mutations in the MECP2 gene and that restoring normal levels of MECP2 in rodent models, even after symptom onset, can reverse most symptoms. While this genetic insight has provided hope for treatment, the incredible complexity of MeCP2 function in neurons has challenged the development of actionable therapeutic strategies. MeCP2 is known to be highly enriched in neurons and bind to methylated DNA, but its subtle effects on transcription have been difficult to understand and reconcile with the severity of Rett syndrome phenotypes. Our laboratory recently performed a meta-analysis of nearly a dozen independent studies of MeCP2-regulated genes and found that MeCP2 selectively controls the expression of very long genes. This observation is highly specific to MeCP2 and is observed in both rodent models and Rett syndrome patients. The high level of MeCP2 in neurons and the tendency for neuronal proteins to be large and encoded by long genes, may explain why MeCP2 mutations preferentially cause neuronal dysfunction. Our preliminary data supports a role of long gene misregulation in the pathogenesis of Rett syndrome because normalizing long gene expression directly with topoisomerase inhibitors improves Rett phenotypes in vitro and in vivo. In neurons, topoisomerases function to unwind DNA during transcription and are required for expression of long genes. The reciprocal control over long gene expression between MeCP2 and topoisomerase, as well as preliminary data demonstrating a physical interaction between these proteins, raise several important mechanistic and therapeutically relevant questions that are the focus of this proposal. 1) to characterize the cellular and behavioral effects of topoisomerase inhibition in the mouse model of Rett syndrome, and 2) to characterize the interaction between MeCP2 and topoisomerase. Together, these studies aim to inform a new therapeutic strategy for Rett syndrome focused on correcting long gene misregulation through direct control of topoisomerase activity.