Prune Belly Syndrome: Mechanisms of Filamin A Mutations

项目摘要 这个项目的总体目标是扩大关于遗传学基础和分子的知识 严重人类多系统先天性泌尿系疾病--梅花腹综合征(PBS)的发病机制 肌肉和结缔组织缺乏的异常。PBS的标志性临床特征 包括因腹壁骨骼发育不全或缺失而导致的皱纹腹肌三联症 肌肉系统，2)继发于膀胱平滑肌病理的巨囊炎，3)双侧 未下降的睾丸。我们在X连锁基因中发现了三个功能增益错义突变 基因细丝蛋白A(Flna)导致综合征和孤立的PBS。Flna是一种丰富的细胞内物质 肌动蛋白-交联蛋白，作为重要的机械传感器，传递力 肌动蛋白和整合素之间的双向作用以及对其他调节因子的结合和调节 跨膜受体或信号分子。Flna调控细胞形态、黏附、基因 转录、低氧反应、胚胎形态发生和细胞收缩。评估 Flna突变对小鼠发育和功能的作用，我们将研究我们的Flna-Gain-Of- 功能突变小鼠在暴露于PBS时具有高穿透性PBS样表型 妊娠低氧(目标1)。使用最先进的结构和生化技术，我们 将表征突变的Flna蛋白结构及其对结合伙伴的影响(目标2)。AS 小鼠来源的FLNA功能增强型膀胱平滑肌细胞具有畸形， 功能障碍的细胞表型，我们将从亚细胞和分子上定义它们的细胞形态和 在暴露于环境压力和刺激物时发挥作用(目标3)。这是一个多学科的 拥有独特科学知识和先进分子工具集的专家团队将联合起来 确定基于FLNA的逼尿肌关键调控机制 导致PBS的功能和功能障碍。这项工作可能会填补我们的一个重要空白 了解FLNA信号并更好地了解逼尿肌的机制 肌肉发生和逼尿肌活动不足，整合信号通路，建立动物模型 PBS，并通过指导未来潜在地影响逼尿肌活动不足的未来管理 合理的治疗设计。

Project Summary The overall goal of this project is to expand the knowledge on the genetic basis and molecular mechanisms of Prune Belly Syndrome (PBS), a severe human multi-system congenital urologic anomaly with muscle and connective tissue deficiencies. Hallmark clinical features of PBS include the triad of 1) wrinkled `prune' belly due to hypoplastic or absent abdominal wall skeletal musculature, 2) megacystis secondary to bladder smooth muscle pathology, and 3) bilateral undescended testes. We discovered three gain-of-function missense mutations in the X-linked gene filamin A (FLNA) causing syndromic and isolated PBS. FLNA is an abundant intracellular actin-crosslinking protein that functions as a crucial mechanosensor, transmitting force bidirectionally between actin and integrins as well as binding and regulating other modulatory transmembrane receptors or signaling molecules. FLNA regulates cell shape, adhesion, gene transcription, hypoxic responses, embryonic morphogenesis, and cell contraction. To assess the role of Flna mutations on mouse development and function, we will study our Flna gain-of- function mutant mice that have a highly penetrant PBS-like phenotype when exposed to gestational hypoxia (Aim 1). Using state-of-the-art structural and biochemical techniques, we will characterize mutant FLNA protein structure and the impact on binding partners (Aim 2). As the mouse-derived Flna gain-of-function bladder smooth muscle cells have a dysmorphic, dysfunctional cell phenotype, we will subcellularly and molecularly define their cell form and function when exposed to environmental stress and stimulants (Aim 3). This multidisciplinary expert team with unique scientific expertise and advanced molecular tool sets will unite to identify FLNA-based critical regulatory mechanisms modulating detrusor smooth muscle function and dysfunction leading to PBS. This work may fill an important gap in our understanding of FLNA signaling and yield greater mechanistic understanding of detrusor myogenesis and detrusor underactivity, integrating signaling pathways, creating animal models of PBS, and potentially impacting future management of detrusor underactivity by guiding future rational therapeutic designs.