Fate of the kidney vasculature during partial neonatal ureteral obstruction

摘要 梗阻性肾病是婴儿和儿童慢性肾脏疾病的主要原因，它不仅损害 肾发生，但也可导致未成熟和成熟的肾单位通过损伤 管腔、管腔和间质腔。拟议的研究项目旨在确定 血管前体及其修复受损肾脏的机制 新生小鼠单侧输尿管部分梗阻(PUUO)与尿路梗阻 人类的胎儿。我们使用遗传细胞命运追踪技术的初步数据显示，在新生儿 PUUO肾动脉树有严重异常，近端肾小管和肾小管缺如。 收集导管细胞。伴随着肾血管损害的是间质细胞的扩张。 最终导致纤维化。值得注意的是，一旦障碍解除，损害就会逆转 血管系统、近端小管和集合管的再生。在之后观察到的惊人的复苏 输尿管梗阻的解除需要重新启动控制细胞命运的发育途径， 位置信息和有组织的增长。我们认为肾脏的血管系统起着直接和 在肾脏损伤后的再生和修复能力中起核心作用。因此，在这项提议中，我们 将检验输尿管梗阻导致血管形态发生缺陷的相关假设 细胞命运的变化以及RBP-J(所有Notch受体的转录效应器)不仅控制 肾血管的正常发育，以及血管及其周围组织的命运和再生 梗阻解除后相关肾单位。总而言之，我们将探索细胞身份的变化和 命运造成了巨大的形态和功能变化，进而决定了组织是否会 健康的或无法恢复的。特定目标1将定义出生后肾脏的血管变化 阻塞性肾病和释放后，特异性靶点2将决定血管细胞的命运 特异性Cre重组和荧光报告小鼠品系，以及特异性靶点3将决定是否 RBP-J在肾血管系统和相关肾单位的再生和维持中起作用 在梗阻过程中和释放后使用Cre重组酶和Cre重组酶诱导表达的小鼠 伴随的荧光报告表达，允许追踪突变细胞的命运。建议数 这项工作将填补我们知识中的一个重要空白：破译涉及到 肾血管修复和再生对婴幼儿和儿童具有潜在的治疗意义 患有慢性肾脏疾病的成年人口不断增加。

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.