Fate of the kidney vasculature during partial neonatal ureteral obstruction

摘要 阻塞性肾病是婴儿和儿童慢性肾脏疾病的主要原因，不仅损害 但也可通过损伤肾组织导致未成熟和成熟肾单位的进行性破坏。 血管、肾小管和间质室。拟议的研究项目旨在确定 血管前体和机制，使他们修复受损的肾脏，使用可逆的模型， 部分单侧输尿管梗阻（pUUO）的新生小鼠，这平行于尿路梗阻， 人类胎儿我们使用遗传细胞命运追踪技术的初步数据显示， pUUO在肾动脉树中存在严重异常，随后是近端小管的丧失， 集合管细胞肾血管损害的同时，肾间质细胞增多 最终导致纤维化。值得注意的是，在释放阻塞后，损害逆转发生， 血管系统、近端小管和集合管的再生。观察到的惊人恢复， 输尿管梗阻的解除需要控制细胞命运的发育途径的重新制定， 位置信息和有组织的增长。我们认为肾脏血管系统对肾脏的功能起着直接的， 在肾脏损伤后再生和修复能力中发挥核心作用。因此，在本提案中， 将检验相关的假设，即输尿管阻塞会导致血管形态发生缺陷， RBP-J（所有Notch受体的转录效应子）不仅控制细胞命运的变化， 肾血管的正常发育，而且血管系统的命运和再生及其 解除阻塞后的相关肾单位。总之，我们将探讨细胞身份的变化， 命运创造了巨大的形态和功能变化，这反过来又决定了组织是否会 健康或无法恢复。具体目标1将定义出生后肾脏的血管变化， 阻塞性肾病和释放后，特异性目标2将决定血管细胞的命运， 特异性Cre重组和荧光报告小鼠系，特异性Aim 3将确定是否 Rbp-J在肾血管和相关肾单位的再生和维持中起作用 在阻塞期间和在其释放之后使用具有Cre重组酶的诱导表达的小鼠， 伴随的荧光报告基因表达允许追踪突变细胞的命运。拟议 这项工作将填补我们知识中的一个重要空白：破译参与细胞和分子机制， 肾血管修复和再生对婴儿和儿童具有潜在的治疗意义， 越来越多的成年人患有慢性肾病。

ABSTRACT Obstructive nephropathy, the leading cause of chronic kidney disease in infants and children not only impairs nephrogenesis but can also lead to progressive destruction of immature and mature nephrons via injury to the vascular, tubular, and interstitial compartments. The proposed research project is designed to identify the vascular precursors and the mechanisms whereby they repair the injured kidney, using a model of reversible partial unilateral ureteral obstruction (pUUO) in the neonatal mouse, which parallels urinary tract obstruction in the human fetus. Our preliminary data using genetic cell fate tracing techniques show that during neonatal pUUO there are severe abnormalities in the renal arterial tree followed by loss of proximal tubular and collecting duct cells. Concomitant with the nephrovascular damage, there is expansion of interstitial cells ultimately leading to fibrosis. Remarkably, upon release of obstruction, reversal of the damage occurs with regeneration of the vasculature, proximal tubules and collecting ducts. The striking recovery observed after release of ureteral obstruction requires the reenactment of developmental pathways that control cell fate, positional information and organized growth. We propose that the kidney vasculature plays a direct and central role in the ability of the kidney to regenerate and repair after injury. Therefore, in this proposal we will test the interrelated hypotheses that ureteral obstruction leads to defective vascular morphogenesis and changes in cell fate and that that RBP-J (the transcriptional effector of all the Notch receptors) not only controls the normal development of the kidney vessels, but also the fate and regeneration of the vasculature and its associated nephrons after release of obstruction. In summary, we will explore how changes in cell identity and fate create massive morphological and functional changes which in turn determine whether the tissue will be healthy or unrecoverable. Specific Aim 1 will define the vascular changes of the postnatal kidney following obstructive nephropathy and after release, Specific Aim 2 will determine the fate of vascular cells using specific Cre recombinant and fluorescent reporter mouse lines, and Specific Aim 3 will determine whether Rbp-J plays a role in the regeneration and maintenance of the renal vasculature and associated nephrons during obstruction and after its release using mice with inducible expression of Cre recombinase and concomitant fluorescent reporter expression that allows to trace the fate of the mutant cells. The proposed work will fill an important gap in our knowledge: deciphering the cellular and molecular mechanisms involved in nephrovascular repair and regeneration has potential therapeutic implications for infants and children and the growing adult population suffering from chronic kidney disease.