DEVELOPMENTAL ROLE OF THE GENE SIX2 IN KIDNEY NEPHRON ENDOWMENT

基因 SIX2 在肾单位发育中的作用

• 批准号: 8360326
• 负责人: SUWIT JACK SOMPONPUN
• 金额: $ 3.78万
• 依托单位: UNIVERSITY OF HAWAII AT MANOA
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-07-01 至 2012-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8360326
• 关键词: Adult; Biogenesis; Centers of Research Excellence; Chronic Kidney Failure; Development; Elderly; Endowment; Funding; Gene Expression; Genes; Genetic; Genetic Transcription; Goals; Grant; Growth; Homeobox Genes; Hypertension; Institutes; Kidney; Kidney Diseases; Metanephric Diverticulum; Methodology; Morphogenesis; Mouse Strains; Mus; Mutant Strains Mice; National Center for Research Resources; Nephrons; Organogenesis; Phenotype; Physiological; Physiology; Principal Investigator; Production; RNA Interference; Research; Research Infrastructure; Resources; Role; Source; United States National Institutes of Health; Work; base; cardiovascular risk factor; cost; design; insight; mouse genome; mouse model; nephrogenesis; research study; restoration

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. Suboptimal kidney development resulting in an in-born deficit in nephron number can have lifelong consequences and is associated with a significant risk of cardiovascular-renal disease in later life, compared to those born with a typical nephron endowment. The long-term goal of the current proposal is to identify cellular mechanisms that drive successful nephron differentiation to achieve optimal nephron endowment. Specifically, we will explore the roles of the homeobox gene sine oculis 2 (six2), and determine whether six2 is involved in the establishment of nephron number during kidney organogenesis. Using an RNAi methodology, experiments are designed to determine whether inactivation of six2 transcription early in nephrogenesis results in a significant decrease in ureteric bud growth and, therefore, nephron number in an organotypic kidney explant culture. Further, using a mouse model of heritable renal hypoplasia that lacks sufficient expression of six2 during development (the Brachyrrhine (Br) mutant mouse), we will take a systematic approach to re-introduce six2 to kidney explants that are prepared from Br mice and determine if exogenous six2 stimulates branching of the ureteric buds leading to an enhanced nephron production. Additionally, we will incorporate a 250 kb Bac containing six2 gene into the Br mouse genome to attempt to increase nephron number and, thereby rescuing the defective renal phenotype associated with six2 deficiency. Following the rescue we will assess if renal physiological features are restored in the adult Br mouse. This proposal will take advantage of the Br mouse strain that displays haploinsufficiency of six2 gene expression and is the only working colony in the world. Similarly, we have fully characterized the physiology of the adult Br mouse that demonstrates hypertension and chronic renal failure facilitating our phenotypic rescue experiments. When considered together, these experiments will provide the fundamental insights that constitute the genetic basis of six2 in renal morphogenesis and specifically establish whether six2 directly determines nephron endowment in the developing kidney. Results from this study will also underscore the importance of six2 in possible nephron restoration approaches in the adult diseased kidney.

该子项目是利用资源的众多研究子项目之一 由 NIH/NCRR 资助的中心拨款提供。子项目的主要支持 并且子项目的主要研究者可能是由其他来源提供的， 包括其他 NIH 来源。 子项目可能列出的总成本 代表子项目使用的中心基础设施的估计数量， NCRR 赠款不直接向子项目或子项目工作人员提供资金。 与出生时具有典型肾单位禀赋的人相比，肾脏发育欠佳导致先天性肾单位数量不足可能会产生终生后果，并且与晚年患心血管肾疾病的显着风险相关。当前提案的长期目标是确定驱动肾单位成功分化以实现最佳肾单位禀赋的细胞机制。具体来说，我们将探讨同源框基因 sine oculis 2 (six2) 的作用，并确定 Six2 是否参与肾脏器官发生过程中肾单位数量的建立。使用RNAi方法，设计实验以确定肾发生早期six2转录失活是否会导致输尿管芽生长显着减少，从而导致器官型肾外植体培养物中肾单位数量的显着减少。此外，使用发育过程中缺乏足够的 Six2 表达的遗传性肾发育不全的小鼠模型（Brachyrine (Br) 突变小鼠），我们将采取系统方法将 Six2 重新引入从 Br 小鼠制备的肾脏外植体中，并确定外源性 Six2 是否会刺激输尿管芽的分支，从而导致肾单位生成增强。此外，我们将把含有 Six2 基因的 250 kb Bac 整合到 Br 小鼠基因组中，以尝试增加肾单位数量，从而挽救与 Six2 缺陷相关的缺陷性肾脏表型。抢救后，我们将评估成年 Br 小鼠的肾脏生理特征是否恢复。该提案将利用 Br 小鼠品系，该品系表现出 Six2 基因表达单倍体不足，并且是世界上唯一的工作群体。同样，我们充分描述了成年 Br 小鼠的生理学特征，证明高血压和慢性肾衰竭有利于我们的表型拯救实验。当综合考虑时，这些实验将提供构成 Six2 在肾脏形态发生中的遗传基础的基本见解，并具体确定 Six2 是否直接决定发育中肾脏中的肾单位禀赋。这项研究的结果还将强调 Six2 在成人患病肾脏的可能肾单位恢复方法中的重要性。