Von Hippel-Lindau mediates nephron progenitor fate via regulation of metabolism

项目概要/摘要： 先天性肾脏结构异常是终末期肾病（ESRD）的主要原因，并导致 发病率和死亡率风险增加。正常的肾单位（肾脏的功能单位）发育至关重要 维持肾脏的正常功能和体内平衡。先天性肾脏异常往往源于 肾单位发育异常导致肾单位丧失。肾单位的丢失与 重要疾病，如ESRD易感性。造成肾单位数量减少的一种损伤是 病理性缺氧VHL/HIF途径是在发育中的人乳腺癌中表达的主要氧敏感途径。 肾在正常的肾脏发育过程中，血管系统的成熟促进了氧气的增加。 浓度.在分子上，这一过程允许泛素连接酶von Hippel Lindau的募集 (VHL)标记缺氧诱导因子1 α（HIF-1 α）的蛋白酶体降解。 我们相信，这种严格调控的途径在一定程度上负责正常的肾单位发育。 此外，最近的研究表明，肾单位祖细胞的代谢谱决定命运 糖酵解有利于自我更新，而线粒体呼吸导致分化。基于 根据这些最近的发现，我相信VHL是代谢转换和肾单位的关键介质， 祖先的命运决定。 为了验证我的假设，我的实验室专门制造了一个条件性缺失VHL的小鼠模型， 在肾单位祖细胞（VHLNP-/-）中。我有初步数据显示组织缺陷和肾脏 早在胚胎第15.5天（E15.5）就出现的畸形。我们的小鼠模型的生存能力丧失 出生后第28天左右（P28），肾功能下降。RNA测序使用分离的 从E17.5 VHLNP-/-的肾单位祖细胞，并揭示参与代谢的关键基因的失调 （糖酵解基因显著上调）。此外，我发现VHLNP-/-肾单位祖细胞仍然存在， 糖酵解甚至在出生后，当氧气容易获得时。为了继续这项调查，我提出两个目标 1)为了确定VHL是否介导糖酵解和线粒体呼吸之间的转换， 信号肾单位祖细胞分化和2）定义VHL和 线粒体参与肾单位祖细胞命运的决定。这些发现将证明严格的必要性 本发明的目的是提供一种新的治疗靶点，用于开发VHL调节，并用于鉴定肾脏疾病治疗的新治疗靶点。!

Project Summary/Abstract: Congenital structural kidney abnormalities are a major cause of end stage kidney disease (ESRD) and lead to increased risk of morbidity and mortality. Normal nephron (functional unit of the kidney) development is crucial for proper function and homeostasis maintenance in the kidney. Congenital kidney abnormalities often stem from aberrant nephron development resulting in a loss of nephrons. Loss of nephrons has been linked to significant disease such as ESRD susceptibility. One insult that causes decreased nephron number is pathological hypoxia. The VHL/HIF pathway is the major oxygen-sensing pathway expressed in the developing kidney. During normal kidney development, vasculature maturation facilitates increases in oxygen concentration. Molecularly, this process allows for the recruitment of the ubiquitin ligase von Hippel Lindau (VHL) in the nephron progenitors to mark hypoxia-inducible factor 1α (HIF-1α) for proteasomal degradation. We believe this tightly regulated pathway is, in part, responsible for normal nephron development. Furthermore, it has recently been shown that the metabolic profile of nephron progenitors dictates fate decisions such that glycolysis favors self-renewal while mitochondrial respiration leads to differentiation. Based on these recent findings, I believe that VHL is a critical mediator of metabolic switching and nephron progenitor fate decisions. To interrogate my hypothesis, my lab generated a mouse model with a conditional deletion of VHL specifically in the nephron progenitors (VHLNP-/-). I have preliminary data indicating histological defects and renal malformations that appear as early as embryonic day 15.5 (E15.5). Loss of viability of our mouse model occurs around postnatal day 28 (P28) after a reduction in renal function. RNA-sequencing was done using isolated nephron progenitors from E17.5 VHLNP-/- and revealed dysregulation of key genes involved in metabolism (significantly up-regulated glycolysis genes). Additionally, I discovered VHLNP-/- nephron progenitors remain glycolytic even after birth when oxygen is readily available. To continue this investigation, I propose two aims 1) to determine whether VHL mediates a switch between glycolysis and mitochondrial respiration to signal nephron progenitor differentiation and 2) to define the interactions between VHL and mitochondria in nephron progenitor fate decisions. These findings will demonstrate the necessity of strict developmental VHL regulation and serve to identify novel therapeutic targets for kidney disease treatment. !