YAP/TAZ in Schwann Cells as potential therapeutic targets in CMT1A and HNPP.

项目摘要 遗传性周围神经病的异质性组被称为夏科-玛丽·图斯病，有 估计患病率为1：25001。在这些疾病中，Charcot Marie Tooth 1A(CMT1A)和遗传性 压力性瘫痪(HNPP)是最常见的神经病。这些疾病是由 编码外周髓鞘蛋白22(PMP22)2的基因重复(CMT1A)或缺失(HNPP)，导致 其在雪旺细胞(SCs)中的过度或低表达，分别为3，4。目前尚无治疗这些衰弱的方法 强调需要确定新的机制来调节PMP22的表达，并阐明 周围神经脱髓鞘的病理机制。最近，由其形成的复合体 带有PDZ结合基序的转录共激活因子(TAZ)5和转录因子TEA结构域1 (TEAD1)6，7，正向调节PMP22的表达8，9。因此，TAZ激活的调节是 一种有趣的治疗途径，降低CMT1A中PMP22的转录，或增加其在CMT1a中的转录 HNPP。此外，PMP22在干细胞生物学中的功能包括调节细胞周期10，11，形成细胞 连接和髓鞘通透性12，13，并测定有髓PN纤维14，15的力学性能。 值得注意的是，SC生物学的这些方面也受到TAZ的调控，以及相关的转录辅助激活因子Yes- 相关蛋白1(YAP)16-20；河马通路21、22的主要下游效应因子。激活的YAP/TAZ 转位到细胞核并与TEAD1-423，24结合，改变了许多必需基因的转录 对于SC的增殖和分化，包括层粘连蛋白受体、整合素、G蛋白GA、EGR2和髓鞘 脂基因8、20、25、26。因此，CMT1A和HNPP中YAP/TAZ激活状态的变化可能会影响 干细胞的生理学，有助于脱髓鞘。因此，我们假设修改TAZ表达可能 通过对PMP22的直接调控，恢复PMP22的正常表达，改善CMT1A的表型。 我们还推测，YAP/TAZ的激活可能在CMT1a和CMT1a的小鼠模型和人类样本中发生改变。 HNPP，可能有助于改变三叉神经节的SC增殖、髓鞘通透性和机械性能。 为了确定调节TAZ激活的效果，遗传消融PMP22-SCs中的TAZ等位基因。 过度表达的小鼠将在形态、电生理、感觉和行为方面进行评估 表型救援。YAP/TAZ激活改变的存在将通过免疫染色和 CMT1A和HNPP人活检标本和小鼠模型的生化分析。对此的研究 拟议的项目将在髓鞘和Glia探索研究所进行，由一个 致力于研究髓鞘及其相关疾病的跨学科科学家小组。整体而言 培训计划将强调科学沟通技能的发展，各种技术的培训， 提高批判性思维和解决问题的能力，以及获得定期临床经验的机会。 这将为培养成为一名内科科学家所需的技能创造理想的环境。

Project Summary The heterogeneous group of inherited peripheral neuropathies referred to as Charcot-Marie Tooth disease, have an estimated prevalence of 1:25001. Among these disorders, Charcot Marie Tooth 1A (CMT1A) and Hereditary Neuropathy with Liability to Pressure Palsy (HNPP) are the most common1. These diseases result from duplication (CMT1A) or deletion (HNPP) of the gene encoding for peripheral myelin protein 22 (PMP22)2, leading to its over or underexpression in Schwann cells (SCs), respectively3,4. There are no cures for these debilitating diseases, highlighting the need to identify novel mechanisms to modulate PMP22 expression, and to elucidate the pathological mechanisms involved in peripheral nerve (PN) demyelination. Recently, the complex formed by the transcriptional coactivator with PDZ-binding motif (TAZ)5 and the transcription factor TEA domain 1 (TEAD1)6,7, was shown to positively regulate PMP22 expression8,9. Therefore, modulation of TAZ activation is an intriguing therapeutic avenue to decrease PMP22 transcription in CMT1A, or increase its transcription in HNPP. Moreover, the functions of PMP22 in SC biology include cell cycle regulation10,11, formation of cellular junctions and myelin permeability12,13, and determining the mechanical properties of myelinated PN fibers14,15. Notably, these aspects of SC biology are also regulated by TAZ, and the related transcriptional coactivator Yes- associated protein 1 (YAP)16–20; the major downstream effectors of the HIPPO pathway21,22. Activated YAP/TAZ translocate to the nucleus and associate with TEAD1-423,24, altering the transcription of many genes essential for SC proliferation and differentiation including laminin receptors, integrins, G-protein Ga, EGR2, and myelin and lipid genes8,20,25,26. Therefore, changes in the activation status of YAP/TAZ in CMT1A and HNPP may impact the physiology of SCs, contributing to demyelination. Thus, we hypothesize that modifying TAZ expression may restore proper PMP22 expression and ameliorate the phenotypes of CMT1A through direct regulation of PMP22. We also postulate that YAP/TAZ activation may be altered in mouse models and human samples of CMT1A and HNPP, potentially contributing to altered SC proliferation, myelin permeability, and mechanical properties of PNs. To determine the effects of modulating TAZ activation, genetic ablation of TAZ alleles in SCs of PMP22- overexpressing mice will be assessed for morphological, electrophysiological, sensory, and behavioral phenotypic rescue. The presence of altered YAP/TAZ activation will be assessed through immunostaining and biochemical analyses of human biopsy samples and mouse models of CMT1A and HNPP. The research for this proposed project will be conducted at the Institute for Myelin and Glia Exploration, composed of an interdisciplinary group of scientists dedicated to the study of myelin and its associated diseases. The overall training plan will emphasize the development of scientific communication skills, training in various techniques, improving critical thinking and problem-solving skills, as well as opportunities for regular clinical experiences. This will create the ideal environment for developing the skills necessary for a career as a physician-scientist.