Critical Roles for Fibroblast Growth Factor Receptors in Bladder Development

成纤维细胞生长因子受体在膀胱发育中的关键作用

• 批准号: 8985305
• 负责人: CARLTON MATTHEW BATES
• 金额: $ 34.65万
• 依托单位: UNIVERSITY OF PITTSBURGH AT PITTSBURGH
• 依托单位国家: 美国
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-07-01 至 2019-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8985305
• 关键词: Adult; Apoptosis; Automobile Driving; Birth; Bladder; Bladder Control; Bladder Diseases; Calculi; Child; Childhood; Collagen; Congenital Abnormality; Data; Defect; Development; Dose; Embryo; Erinaceidae; Failure; Fibroblast Growth Factor Receptor 2; Fibroblast Growth Factor Receptors; Fibrosis; Future; Genetic; Genetic Determinism; Health; Infection; Infiltration; Injury; Kidney; Kidney Failure; Knock-out; Lamina Propria; Lead; Life; Mesenchyme; Molecular; Mus; Muscle; Newborn Infant; Pathway interactions; Patients; Pattern; Regulation; Relative (related person); Role; Signal Transduction; Testing; Urinary Retention; Urinary tract; Urinary tract infection; aged; chemical genetics; effective therapy; genetic approach; in vivo; inhibitor/antagonist; mouse model; mutant; postnatal; pressure; public health relevance; receptor; research study; smoothened signaling pathway; treatment strategy

 DESCRIPTION (provided by applicant): Developmental bladder defects can lead to numerous health problems throughout life including pediatric kidney failure, urinary tract infections, stone, and urinary retention; however, genetic determinants of bladder diseases are largely unknown. The application's broad long-term objectives are to elucidate the molecular control of bladder development to develop effective therapies for structural bladder disease. Presently, most of the molecular control of bladder development is unknown. Fibroblast growth factor receptor 2 (Fgfr2) is expressed in developing bladder mesenchyme (future muscle and lamina propria); however, global deletion of Fgfr2 in mice leads to early embryonic lethality prior to the onset of urinary tract development, making the roles of the receptor in bladder development unclear. To circumvent the early lethality of the global knockouts, a Tbx18cre line was used to conditionally delete Fgfr2 in the bladder mesenchyme (Fgfr2BM-/-). Preliminary data show that while Fgfr2BM-/- embryonic bladders total bladder volumes are unchanged, the mutants have a relative reduction in the volume of the outer condensing mesenchyme (future muscle) and a decrease in muscle marker expression vs. controls. Conversely, Fgfr2BM-/- bladders have a relative increase in volume of the inner mesenchyme (future lamina propria) and higher expression of early collagen markers with infiltration into the muscle. Early postnatal mutant bladders have histological abnormalities and functional defects including decreases in contractility, poor compliance, and high pressures; aged Fgfr2BM-/- mice develop severe bladder distention with fibrosis and myogenic failure (resembling atonic bladders) and also develop kidney injury. Mechanistically, Fgfr2BM-/- embryonic bladders appear to have increased sonic hedgehog (Shh) activity (and other pathways downstream of hedgehog such as Wnt and Bmp4), which likely mispatterns the mesenchyme. Fgfr2 suppression of hedgehog appears to by regulation of Hh co-receptors Cdon and Boc. Finally preliminary bladder culture experiments suggest a rescue of mutant bladder muscle defects with low doses of a hedgehog inhibitor. The overarching hypothesis is that loss of Fgfr signaling in bladder mesenchyme leads to early developmental patterning defects that have significant postnatal consequences. To test the hypothesis, the following aims are proposed: Aim1: Characterize the progressive histological, functional, and signaling defects in Fgfr2BM-/- bladders. Structural and molecular bladder mispatterning will be interrogated in Fgfr2BM-/- embryos and newborn mice. Structural and functional consequences of developmental bladder mispatterning will be determined in postnatal mice. Signaling defects downstream of Fgfr2 will also be characterized in mutant bladders. Aim 2: Determine the molecular mechanisms driving the patterning defects in the Fgfr mutants. Perturbations in hedgehog signaling (and other potential pathways downstream of hedgehog such as Bmp4 and Wnt) will be interrogated in embryonic Fgfr2BM-/- bladders. Chemical and genetic approaches will be used ex vivo and in vivo to attempt rescue of bladder defects in Fgfr2BM-/- mice.

 描述（由申请人提供）：发育性膀胱缺陷可导致一生中的许多健康问题，包括小儿肾衰竭、尿路感染、结石和尿潴留;然而，膀胱疾病的遗传决定因素在很大程度上是未知的。该应用程序的广泛的长期目标是阐明膀胱发育的分子控制，以开发结构性膀胱疾病的有效疗法。目前，大多数膀胱发育的分子控制是未知的。成纤维细胞生长因子受体2（Fgfr 2）在发育中的膀胱间充质（未来的肌肉和固有层）中表达;然而，小鼠中Fgfr 2的整体缺失导致在尿路发育开始之前的早期胚胎死亡，使得受体在膀胱发育中的作用不清楚。为了避免全局敲除的早期致死性，使用Tbx 18 cre系来条件性地缺失膀胱间充质中的Fgfr 2（Fgfr 2BM-/-）。初步数据显示，虽然Fgfr 2BM-/-胚胎膀胱的总膀胱体积不变，但突变体与对照相比具有外部浓缩间充质（未来肌肉）体积的相对减少和肌肉标志物表达的减少。相反，Fgfr 2BM-/-膀胱具有内部间充质（未来的固有层）体积的相对增加和早期胶原蛋白标志物的较高表达，并浸润到肌肉中。出生后早期突变膀胱具有组织学异常和功能缺陷，包括收缩性降低、顺应性差和高压;老年Fgfr 2BM-/-小鼠发生严重膀胱膨胀伴纤维化和肌源性衰竭（类似于失张力膀胱），并且还发生肾损伤。从机制上讲，Fgfr 2BM-/-胚胎膀胱似乎具有增加的音刺猬（Shh）活性（以及刺猬下游的其他途径，如Wnt和Bmp 4），这可能使间充质发生错误模式。Hedgehog的Fgfr 2抑制似乎是通过调节Hh共受体Cdon和Boc实现的。最后，初步的膀胱培养实验表明，救援突变膀胱肌肉缺陷与低剂量的刺猬抑制剂。总体假设是膀胱间充质中FGFR信号传导的丧失导致具有显著出生后后果的早期发育模式缺陷。为了检验这一假设，提出了以下目标：目标1：表征Fgfr 2 BM-/-膀胱中进行性组织学、功能和信号传导缺陷。将在Fgfr 2BM-/-胚胎和新生小鼠中研究结构和分子膀胱错误模式。将在出生后小鼠中确定发育膀胱错误模式的结构和功能后果。Fgfr 2下游的信号传导缺陷也将在突变膀胱中表征。目的2：确定驱动Fgfr突变体中图案缺陷的分子机制。将在胚胎Fgfr 2BM-/-膀胱中询问hedgehog信号传导（和hedgehog下游的其他潜在途径，如Bmp 4和Wnt）的扰动。将使用化学和遗传方法离体和体内尝试挽救Fgfr 2BM-/-小鼠中的膀胱缺陷。