Retinoic acid gene regulatory networks in the mammalian kidney

项目概要/摘要 适当的肾单位禀赋和分割是建立健康肾脏的必要条件。肾单位数 在人类中是高度可变的。低肾单位数与高血压风险增加相关， 终末期肾病更好地理解肾发生的机制将有助于我们设计一种 增加肾单位禀赋的方法。沿着近端-远端轴，肾小体连接到 集合管通过近端小管、Henle袢和远端小管。每个肾单位段执行 不同的生理功能。了解多能肾单位祖细胞如何决定其细胞命运 决定发育成不同的肾单位节段不仅是建立一个功能性的肾单位， 体外，而且还用于促进肾损伤后的再生。在这项研究中，我们将探讨如何 视黄酸信号传导调节肾单位禀赋和分裂。我们发现，在小鼠中， 间充质肾单位祖细胞中的视黄酸信号传导导致肾单位祖细胞显著降低 捐赠。我们还发现，在新生的发育中的肾单位中抑制视黄酸信号传导， 干扰近曲小管细胞的形成和成熟。我们的初步数据表明维甲酸 酸性信号在肾发生的早期和晚期起着重要作用，有助于形成适当的肾单位。 禀赋和分割。在目标1中，通过体内遗传操纵视黄酸信号传导， 在体外，我们将测试视黄酸信号传导是否需要间充质到上皮细胞， 通过与Wnt/β-catenin信号传导协调来促进肾单位祖细胞的转变。为了了解维甲酸 信号有助于肾单位的捐赠，我们将确定维甲酸基因调控网络， 肾单位祖细胞。在目的2中，通过进行维甲酸的遗传功能获得和功能丧失研究， 酸信号在新形成的发展肾单位，我们将测试是否视黄酸信号是必要的， 足以形成和成熟的近端小管。我们还将确定视黄酸基因 发育中的肾单位的调控网络，以了解视黄酸信号如何调控肾单位 细分我们提出的研究将填补长期以来在分子机制方面的知识空白 作为决定肾单位禀赋以及近端小管形成或成熟的基础 在哺乳动物中。我们的长期目标是设计一种方法，在发育过程中增加肾单位的捐赠 并产生用于潜在的细胞替代疗法的肾单位小管细胞。

Project Summary/Abstract Proper nephron endowment and segmentation are essential for building healthy kidneys. Nephron number is highly variable among humans. Low nephron number is associated with increased risk of hypertension and end-stage renal disease. A better understanding of the mechanisms of nephrogenesis will help us devise a way to increase nephron endowment. Along the proximal-distal axis, the renal corpuscle is connected to the collecting duct via the proximal tubule, loop of Henle, and distal tubule. Each nephron segment carries out distinct physiological functions. Understanding how multipotent nephron progenitors make their cell fate decisions to develop into different nephron segments is essential not only for building a functional nephron in vitro but also for promoting regeneration after kidney injury. In this proposed study, we will investigate how retinoic acid signaling regulates nephron endowment and segmentation. We found that, in mice, inhibition of retinoic acid signaling in mesenchymal nephron progenitor cells caused significantly lower nephron endowment. We also found that inhibition of retinoic acid signaling in the newly formed developing nephron interfered with the formation and maturation of proximal tubule cells. Our preliminary data suggest that retinoic acid signaling plays important roles in early and later stages of nephrogenesis, contributing to proper nephron endowment and segmentation. In Aim 1, by manipulating retinoic acid signaling genetically in vivo and pharmacologically in vitro, we will test if retinoic acid signaling is required for mesenchymal-to-epithelial transition of nephron progenitors by coordinating with Wnt/-catenin signaling. To understand how retinoic acid signaling contributes to nephron endowment, we will determine the retinoic acid gene regulatory network in nephron progenitors. In Aim 2, by performing genetic gain-of-function and loss-of-function studies of retinoic acid signaling in the newly formed developing nephron, we will test if retinoic acid signaling is necessary or sufficient for the formation and maturation of proximal tubules. We will also determine the retinoic acid gene regulatory network in the developing nephrons to understand how retinoic acid signaling regulates nephron segmentation. Our proposed studies will fill a longstanding gap of knowledge in the molecular mechanisms underlying the determination of nephron endowment as well as the formation or maturation of proximal tubules in mammals. Our long-term goals are to devise a way to increase nephron endowment during development and to generate nephron tubule cells for potential cell replacement therapy.