Visualizing and elucidating the FGF-dependent mechanisms of urethral morphogenesis

可视化并阐明尿道形态发生的 FGF 依赖性机制

• 批准号: 10311049
• 负责人: Chase Dallas Bryan
• 金额: $ 0.81万
• 依托单位: UNIVERSITY OF FLORIDA
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-01-01 至 2022-01-14
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10311049
• 关键词: Adhesions; Affect; Anogenital region; Architecture; Atlases; Basement membrane; Bilateral; Biomechanics; Birth; Buffers; Cell Adhesion Molecules; Cell Proliferation; Cell-Cell Adhesion; Cells; Cellular biology; Clitoris; Congenital Abnormality; Coupled; Data; Defect; Development; Distal; Dorsal; Drosophila genus; Ectoderm; Ectoderm Cell; Embryo; Endocrine Disruptors; Endoderm; Endoderm Cell; Environmental Risk Factor; Epithelial; Epithelial Cells; Event; Exposure to; Extracellular Matrix; Failure; Female; Female genitalia; Fibroblast Growth Factor; Four-dimensional; Future; Genetic; Genital; Genitalia; Germ Layers; Hydrogels; Hypospadias; Imaging Techniques; Light; Live Birth; Male Genital Organs; Maps; Mechanics; Membrane; Mesenchymal; Mesenchyme; Mesoderm; Mesoderm Cell; Microscopy; Modeling; Molecular; Morphogenesis; Movement; Mus; Mutant Strains Mice; Mutation; Operative Surgical Procedures; Organ Culture Techniques; Pathway interactions; Physical condensation; Positioning Attribute; Prevention; Preventive measure; Process; Recurrence; Research; Resources; Risk; Role; Scrotum; Shapes; Side; Signal Pathway; Signal Transduction; Site; Skin; Structure; Surface Ectoderm; System; Testing; Thinness; Tissues; Tube; Urethra; Vagina; Work; Zebrafish; base; body system; cell motility; cell type; external genitalia; genetic analysis; grasp; in utero; insight; laminin-5; lateral line; live cell imaging; male; malformation; mechanical force; membrane assembly; migration; mouse model; mutant; novel; penis; prevent; sex; sexual dimorphism

PROJECT SUMMARY Hypospadias is a birth defect wherein the urethral opening is displaced from the distal end of the penis and instead terminates on the ventral side of the penis, or in severe cases, on the scrotum or perineum. Hypospadias is one of the most common birth defects, affecting approximately 1 in 125 live male births. Surgery is currently the only treatment, which comes with a risk of complications and recurrence. Recent work has demonstrated that both genetic factors and environmental factors such as embryonic exposure to endocrine disrupting chemicals can increase the rate of hypospadias. Despite these studies, we still do not have a good grasp on what aspects of genitalia morphogenesis become disrupted and result in hypospadias. The embryonic genital tubercle (GT) gives rise to either the penis or clitoris, and contains tissues from all three germ layers. The endodermal component of the GT primarily gives rise to the urethra, mesodermal cells contribute to supportive structures within the external genitalia, and the ectoderm gives rise to the overlying skin. During GT development, the endoderm and ectoderm are connected at an endoderm/ectoderm junction (EEJ) on the ventral side of the GT, forming one of very few sites in the body where such a junction occurs. This junction is remodeled away over the course of penis development and urethral internalization, leading to distal positioning of the urethral meatus; the EEJ remains intact during and after clitoral development, resulting in the ventral position of the urethral opening between the clitoris and vagina. This leads to the hypothesis that EEJ remodeling is necessary for urethral internalization in the penis, and disruptions to the EEJ cause hypospadias. To test this hypothesis, this proposal uses mouse mutants in the Fgf signaling pathway as a model to test how disruptions of the EEJ result in GT malformations: mice with Fgfr2 mutations display endodermal and ectodermal defects in the GT and subsequently develop severe hypospadias. Aim 1 of this proposal will test how Fgfr2 regulates cell movements at the EEJ during urethral internalization; this aim makes use of a novel GT organ culture system coupled with four-dimensional live imaging techniques to directly visualize morphogenesis of the mouse EEJ. Aim 2 will examine the biomechanical mechanisms underlying urethral internalization and test the role of extracellular matrix adhesion in contributing to EEJ development. The findings from this proposal will generate an atlas of the cell and tissue movements which occur during urethral formation in the mouse, a resource which is not available for most mammalian organ systems. The research proposed here will not only shine a light onto the morphogenetic mechanisms underlying normal external genitalia development, but will also provide insight into how hypospadias arise and will help shape potential preventative measures for this common congenital defect.

项目摘要 Hypospadias是一种先天缺陷，其中尿道开口从阴茎的远端移位 相反，在阴茎或阴茎上终止于阴茎的腹侧或严重的情况。 Hypospadias是最常见的先天缺陷之一，影响了125个活着的男性分娩中的大约1个。 手术目前是唯一的治疗方法，它具有并发症和复发的风险。最近的工作 已经证明了遗传因素和环境因素，例如胚胎暴露于 内分泌破坏化学物质可以提高催生率。尽管有这些研究，我们仍然没有 对生殖器形态发生的哪些方面有良好的掌握受到破坏并导致催生。 胚胎生殖结节（GT）产生阴茎或阴蒂，并包含来自 这三个细菌层。 GT的内胚层成分主要引起尿道，中胚层 细胞有助于外生殖器中的支撑性结构，外胚层产生 皮肤上覆盖。在GT开发过程中，内胚层和外胚层在内胚层/外胚层连接 GT腹侧的交界处（EEJ），形成了体内少数几个位置之一 发生。在阴茎发展和尿道内部化过程中，该交界被重塑， 导致尿道肉类的远端定位；在阴蒂期间和之后，EEJ保持完整 发育，导致阴蒂和阴道之间尿道开口的腹侧位置。这 导致假设EEJ重塑对于阴茎中的尿道内在化是必要的，并且 对EEJ的破坏会导致催生。为了检验该假设，该提案在 FGF信号通路作为测试EEJ的破坏导致GT畸形的模型：带有GT的畸形： FGFR2突变在GT中显示内皮表皮和外皮缺陷，随后出现严重 Hypospadias。该提案的目标1将测试FGFR2如何调节尿道期间EEJ的细胞运动 内在化；此目的是利用一种新型的GT器官培养系统，以及四维现场 成像技术直接可视化小鼠EEJ的形态发生。 AIM 2将检查 尿道内在化的生物力学机制并测试细胞外基质粘附的作用 为EEJ开发做出贡献。 该提案的发现将产生细胞和组织运动的地图集 在小鼠中的尿道形成期间，大多数哺乳动物器官系统无法使用的资源。 这里提出的研究不仅会将灯光照耀到正常的形态发生机制 外部生殖器的发展，但也将提供有关催生的出现的见解，并将有助于塑造 这种常见先天性缺陷的潜在预防措施。