Study of SBMA mutant AR transcriptional network in stem cell-derived motor neurons and skeletal muscle

总结 X连锁脊髓延髓肌萎缩症（也称为SBMA或肯尼迪病）是一种罕见的 一种神经肌肉疾病，特征为由于下运动神经元引起的成人发作近端肌无力 退化SBMA患者表现出雄激素不敏感的迹象，包括男性乳房发育，生育能力下降， 和睾丸萎缩SBMA是由雄激素中的CAG-聚谷氨酰胺（polyQ）重复扩增引起的。 受体（AR）基因，并且是九种CAG-polyQ重复序列疾病家族的一员，包括 亨廷顿氏病。几十年来，对神经系统疾病基础的研究集中在 神经元功能障碍对疾病发病机制的贡献。然而，在过去的十年里， 运动神经元疾病领域越来越多的证据挑战了流行的神经中心理论， 许多神经系统疾病的病因。最近，我们发现在控制运动中细胞死亡增加， 与对照相比，经受来自SBMA iPSC衍生的骨骼肌的条件培养基的神经元 衍生的骨骼肌。这一发现强调了肌肉毒性在SBMA疾病中的重要性 发病机制然而，对于治疗目的，在文献中缺乏共识。不同群体 已经能够证明针对骨骼肌或中枢神经系统的成功治疗方法， 神经系统使用不同的SBMA动物模型。因此，有必要对SBMA进行研究 在人类背景中，受影响的细胞类型、骨骼肌和运动神经元上的AR突变。 因此，申请人Helen C.米兰达提议将联合收割机 干细胞生物学和运动神经元疾病建模到功能基因组学的导师，以测试 假设AR转录网络在SBMA中是组织特异性的。该项目将测试这一假设 通过结合从SBMA和等基因组产生的AR全基因组占有率和基因表达数据集， 控制iPSC衍生的骨骼肌和运动神经元。这项工作将促进对 人突变型AR对SBMA发病机制的分子机制，并评估iPSC衍生的 骨骼肌和运动神经元的工具来开发SBMA体外研究。米兰达博士是一位新助理 凯斯西储遗传学系和神经科学系教授 大学她将把75%的时间用于该奖项下的研究，并将补充她的研究， 基因组和转录组分析的教学培训。该培训将包括1）部门和 大学课程，2）研讨会和期刊俱乐部，3）负责任地开展研究课程，4）国家 和国际会议。米兰达博士将由安东尼·温肖-鲍里斯博士和安博士指导 凯斯西储大学的哈里斯。这些著名的科学家都是STEM领域的著名专家 细胞生物学和功能基因组学。米兰达博士与她的每一位导师会面，讨论这个项目， 在此期间，我将继续定期与他们会面（在指导信中指定）。 奖她预计将产生相应的或共同通信作者的手稿， 在这个奖项的过程中竞争R级赠款。该项目将整合米兰达博士目前的 专业知识与额外的培训，以制定一个全面的，独立的研究计划。

SUMMARY X-linked spinal and bulbar muscular atrophy (also known as SBMA or Kennedy's disease) is a rare neuromuscular disorder characterized by adult-onset proximal muscle weakness due to lower motor neuron degeneration. SBMA patients display signs of androgen insensitivity, including gynecomastia, reduced fertility, and testicular atrophy. SBMA, is caused by a CAG-polyglutamine (polyQ) repeat expansion in the androgen receptor (AR) gene and is one member of a family of nine CAG-polyQ repeat disorders that includes Huntington’s disease. For decades, research into the basis of neurological disease focused upon the contribution of neuronal dysfunction to disease pathogenesis. However, over the last ten years, there has been growing evidence in the motor neuron disease field that challenges the prevailing neurocentric theory of the etiology of many neurological diseases. Recently, we have identified increased cell death in control motor neurons subjected to conditioned media from SBMA iPSC-derived skeletal muscles compared to control derived skeletal muscles. This finding emphasizes the importance of muscle toxicity in SBMA disease pathogenesis. For therapeutic purposes, however, there is lack of consensus in the literature. Different groups have been able to demonstrate successful treatments targeting either the skeletal muscle or the central nervous system using different SBMA animal models. Consequently, there is a need for studies of the SBMA AR-mutation on the affected cell types, skeletal muscle and motor neurons, in a human background. Therefore, the applicant, Dr. Helen C. Miranda, is proposing to combine her considerable experience in stem cell biology and motor neuron disease modeling to a mentorship in functional genomics, to test the hypothesis that the AR transcriptional network is tissue-specific in SBMA. This project will test this hypothesis by combining AR genome wide occupancy and gene expression data sets generated from SBMA and isogenic controls iPSC-derived skeletal muscle and motor neurons. This work will advance understanding on the molecular mechanisms of human mutant AR to SBMA pathogenesis and evaluate the utility of iPSC-derived skeletal muscles and motor neurons tool to develop SBMA in vitro studies. Dr. Miranda is a new Assistant Professor in the Department of Genetics and the Department of Neuroscience at Case Western Reserve University. She will devote 75% of her time to research under this award and will supplement her research with didactic training in genomic and transcriptomic analyses. This training will be comprised of 1) departmental and university courses, 2) seminars and journal clubs 3) responsible conduct of research courses and 4) national and international conferences. Dr. Miranda will be mentored by Dr. Anthony Wynshaw-Boris and Dr. Ann Harris at Case Western Reserve University. These established scientists are both renowned experts in stem cell biology and functional genomics. Dr. Miranda has met with each of her mentors to discuss this project and will continue to meet with them at regular intervals (specified in mentorship letters) during the course of this award. She is expected to produce manuscripts as corresponding or co-corresponding author and be competitive for R-level grants during the course of this award. This project will integrate Dr. Miranda’s current expertise with additional training to develop a well-rounded, independent research program.