Neural Crest Contributions to the Bladder

描述（由申请人提供）：神经支配决定膀胱逼尿肌的适当收缩性。当适当地神经支配时，膀胱是顺应性的，并且可以在低压下保持可变体积的尿液。膀胱调节内压的失败导致高压转移到肾脏，随后肾小球损伤;因此，神经源性膀胱疾病患者发生肾衰竭和肾移植的风险较高。脊柱裂是小儿神经源性膀胱最常见的病因。神经管缺陷和膀胱功能障碍之间的关联以及支配膀胱的交感神经和副交感神经输入的神经嵴（NC）起源意味着NC衍生物是正常膀胱发育的重要参与者。膀胱神经支配的解剖学和免疫组织化学研究已经确定了神经成分和一些神经递质亚型，存在于晚期胎儿和出生后的发展。然而，缺乏对来自NC的膀胱细胞类型的全面了解。识别NC谱系和控制其在膀胱内分化的基因对于了解神经源性膀胱的病因和潜在治疗方法具有重要意义。体外培养的神经嵴干细胞可分化为神经元、神经胶质和肌成纤维细胞。一个关键的问题，仍然有待解决的是，是否只有膀胱神经支配是NC衍生的，或者如果神经嵴干细胞也有助于在这个器官的其他谱系。由于膀胱平滑肌的缺陷已报告胎儿脊髓脊膜膨出，NC和平滑肌分化之间的关系是特别感兴趣的。我们将通过分析膀胱个体发育过程中的工程小鼠模型来检验膀胱内的多个谱系是NC衍生的这一假设。我们已经实施了能够追踪表达SoxlO的神经嵴干细胞的BAG重组方法。目的1将建立NC迁移到膀胱中的时间曲线，并定义膀胱中谱系标志物与SoxlO转基因表达的共定位。目的2将通过实施Cre-/oxP命运作图来全面鉴定膀胱中NC衍生的细胞类型。在目标3中，我们将从发育中的膀胱中捕获神经嵴干细胞，以确定发育潜力的时间变化，并确定骶骨NC特异性的转录谱。目的4：探讨脊髓发育不良小鼠脊髓裂模型中NC发生改变的机制。我们的分析将开拓探索膀胱中的NC谱系通路，确定用于未来神经源性膀胱患者疾病等位基因分析的候选基因，并开始确定脊柱裂小鼠模型中NC发育改变的机制。拟议的研究直接解决了“儿科泌尿外科战略计划”中所述的膀胱发育基础研究的多种需求，并响应了“膀胱和下尿路基础研究”计划公告的目标。

DESCRIPTION (provided by applicant): Neural innervation determines appropriate contractility of the detrusor muscle in the bladder. When appropriately innervated, the bladder is compliant and can hold variable volumes of urine at low pressures. Failure of the bladder to modulate internal pressures results in transfer of high pressures to the kidney with subsequent glomerular damage; thus, patients with neurogenic bladder disease are at high risk for renal failure and renal transplantation. Spina bifida is the most common etiology of pediatric neurogenic bladder. The association between neural tube defects and bladder dysfunction as well as the neural crest (NC) origin of sympathetic and parasympathetic inputs that innervate the bladder implies that NC derivatives are essential participants in normal bladder development. Anatomical and immunohistochemical studies of bladder innervation have identified neural components and some of the neurotransmitter subtypes that are present in late fetal and postnatal development. However, a comprehensive understanding of bladder cell types that derive from NC is lacking. Identification of NC lineages and genes that control their differentiation within the bladder is of significant relevance to understanding the etiology and potential treatments for neurogenic bladder. In vitro neural crest stem cells give rise to neurons, glia and myofibroblasts. A critical question that remains to be addressed is whether only bladder innervation is NC-derived or if neural crest stem cells also contribute to additional lineages in this organ. Because deficiencies of bladder smooth muscle have been reported in fetuses with myelomeningocele, the relationship between NC and smooth muscle differentiation is of particular interest. We will test the hypothesis that multiple lineages within the bladder are NC-derived by analysis of engineered mouse models throughout ontogeny of the bladder. We have implemented BAG recombination methods that enable tracing of neural crest stem cells expressing SoxlO. Aim 1 will establish a temporal profile of NC migration into the bladder and define co-localization of lineage markers in the bladder with SoxlO transgene expression. Aim 2 will comprehensively identify NC- derived cell types in the bladder by implementing Cre-/oxP fate mapping. In Aim 3 we will capture neural crest stem cells from the developing bladder to define temporal changes in developmental potential and identify transcriptional profiles specific to sacral NC. Aim 4 will define mechanisms of altered NC development in myelodysplastic bladders of mouse spina bifida models. Our analysis will pioneer exploration of NC lineages pathways in the bladder, identify candidate genes for future analysis of disease alleles in neurogenic bladder patients and begin to define mechanisms of altered NC development in spina bifida mouse models. The proposed studies directly address multiple needs for basic research in bladder development as stated in the "Strategic Plan for Pediatric Urology" and are responsive to the objectives of the "Basic Research in the Bladder and Lower Urinary Tract" Program Announcement.