Mechanisms controlling distal nephron maturation

控制远端肾单位成熟的机制

基本信息

批准号：
9900781
负责人：
Alexander Georg Marneros
金额：
$ 35.48万
依托单位：
MASSACHUSETTS GENERAL HOSPITAL
依托单位国家：
美国
项目类别：
财政年份：
2019
资助国家：
美国
起止时间：
2019-04-01 至 2023-01-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/9900781
关键词：
Activities of Daily Living Affect Age BTB/POZ Domain Cell Culture System Cell Differentiation process Cell Maturation Chronic Kidney Failure Core Protein Cyst Cystic Kidney Diseases Cystic kidney Data Defect Dilatation - action Distal Distal convoluted renal tubule structure Electrolytes Epithelial Epithelial Cells Epithelium Event Failure Growth Homeostasis Human Impairment In Vitro Kidney Kidney Diseases Kidney Failure Knockout Mice Laboratories Lead Life Limb structure Mediating Missense Mutation Molecular Morphology Mus Mutation Nephrons Nuclear Nuclear Protein Pathology Pathway interactions Patients Phase Phosphoric Monoester Hydrolases Protein Isoforms Proteins Renal function Role Signal Transduction Sodium Chloride Syndrome Thick Transcription Repressor Up-Regulation Urine beta catenin clinically relevant derepression early onset experimental study in vivo innovation kidney cell kidney fibrosis knock-down mouse model nephrogenesis overexpression planar cell polarity postnatal prevent spatiotemporal

项目摘要

SUMMARY: The distal nephron of the kidney has essential functions for urine concentration and electrolyte homeostasis. Defects in specific segments of the distal nephron can cause various kidney diseases, such as salt-losing tubulopathies that are characterized by an inability to concentrate urine. All nephrons are formed in the mouse by ~P3 postnatally, but the full functional capacity of the distal nephron is only achieved after a subsequent maturation phase, during which the distal nephron undergoes significant growth and functional changes. The maturation of the distal nephron has remained largely unstudied and it is not known which molecular and cellular mechanisms drive distal nephron maturation. Here, we will investigate the molecular mechanisms that orchestrate distal nephron maturation. We have identified the BTB-domain containing nuclear protein KCTD1, a transcriptional repressor, as an essential regulator of distal nephron maturation, for which a function in the kidney was previously unknown. We found KCTD1 to be expressed only in the distal nephron epithelium in the kidney and show that its deficiency impairs maturation and function of the thick ascending limb of Henle and the distal convoluted tubule, resulting in an early-onset salt-losing tubulopathy with a diminished ability to concentrate urine. The immature tubules undergo progressive dilatation and form enlarging cysts, changes leading to late-onset kidney fibrosis and renal failure. Inducible inactivation of KCTD1 during the distal nephron maturation phase leads to these distal tubule defects, but not when KCTD1 is inactivated in fully matured kidneys. Importantly, we identified missense mutations in KCTD1 in patients that develop kidney abnormalities resembling the findings in KCTD1 null mice, establishing the clinical relevance of KCTD1 for human kidney functions. Mechanistically, we show that loss of KCTD1 leads to postnatal derepression of the nuclear protein DAPL1 which precedes the manifestation of the distal nephron maturation defect and is associated with loss of the Wnt/planar cell polarity protein Dvl2 and increased canonical Wnt/β-catenin signaling. Furthermore, we show that DAPL1 regulates primary human distal nephron epithelial cell differentiation. Here, we will investigate the molecular mechanisms of how KCTD1 and DAPL1 regulate distal nephron maturation. Our proposed experiments are highly innovative and have significant clinical relevance, as they aim to uncover fundamental new mechanisms that are required for distal nephron maturation and which are impaired in several kidney disorders. Moreover, we will investigate how defects in distal nephron maturation affect late-onset chronic kidney disease-like pathologies and cystic kidney disease. The scientific premise for this application is strong and builds on extensive preliminary data, mouse models that have already been established in our laboratory, and a primary human TAL/DCT cell culture system for which the feasibility of the proposed experiments has been clearly established.

摘要：肾脏的远端肾单位对于尿液浓缩和电解质稳态具有重要功能。远端肾单位特定节段的缺陷可导致各种肾脏疾病，例如失盐以无法浓缩尿液为特征的肾小管病所有肾单位均在小鼠体内形成。出生后约 P3，但远端肾单位的全部功能只有在随后的成熟阶段，在此期间远端肾单位经历显着的生长和功能变化。远端肾单位的成熟在很大程度上尚未被研究，也不知道哪些分子和细胞驱动远端肾单位成熟的机制在这里，我们将研究其分子机制。协调远端肾单位的成熟。我们已经鉴定出含有 BTB 结构域的核蛋白 KCTD1（一种转录抑制因子）远端肾单位成熟的重要调节因子，其在肾脏中的功能以前未知。发现 KCTD1 仅在肾脏远端肾单位上皮中表达，表明其缺陷损害亨利升粗肢和远端曲管的成熟和功能。早发性失盐性肾小管病，其尿液浓缩能力下降。进行性扩张并形成扩大的囊肿，这些变化导致迟发性肾纤维化和肾病远端肾单位成熟阶段 KCTD1 的诱导失活导致这些远端肾小管衰竭。缺陷，但当 KCTD1 在完全成熟的肾脏中失活时则不会。重要的是，我们发现了错义。出现肾脏异常的患者中的 KCTD1 突变与 KCTD1 缺失小鼠中的发现类似，从机制上讲，我们证明了 KCTD1 与人类肾功能的临床相关性。 KCTD1 导致出生后核蛋白 DAPL1 的去抑制，这先于出现远端肾单位成熟缺陷，与 Wnt/平面细胞极性蛋白 Dvl2 的丢失相关此外，我们发现 DAPL1 调节主要的人类远端。在这里，我们将研究KCTD1和肾单位上皮细胞分化的分子机制。 DAPL1 调节远端肾单位的成熟。具有重要的临床意义，因为他们的目标是揭示远端所需的基本新机制此外，我们将研究肾单位的成熟度如何在几种肾脏疾病中受损。远端肾单位成熟缺陷影响迟发性慢性肾病样病理和囊性肾该应用的科学前提是强大的，并且建立在广泛的初步数据（小鼠）的基础上。我们实验室已经建立了模型，以及原代人类TAL/DCT细胞培养系统为此，所提议的实验的可行性已得到明确确立。