Regulation of Podocyte Differentiation by the Transcription Factor EBF1

7.项目摘要/摘要 成熟的后肾通过输尿管芽伸入后肾形成。 间充质随后浓缩，经历间充质到上皮的转变，并融合到 芽的突起形成成熟的肾单位。多条协调的信号通路、细胞因子和 转录因子已被确定为这一过程中不可或缺的一部分，但我们在这里介绍我们的 早期B细胞因子1(EBF1)作为一种全新的转录因子的鉴定 肾小球成熟。在缺乏EBF1的情况下，肾脏发育为皮质变薄，肾小球减少 成熟，肾源性胚泡，持续到成年期。形成的肾小球与 功能障碍的血管形成，新月体，足细胞严重消失，这些小鼠表现为蛋白尿和 血尿素氮升高。我们认为，EBF1在中后期正在发挥作用 足细胞分化。该提案包含两个具体目标，旨在(1)确定 EBF1在肾发生中的作用：(2)确定EBF1的直接靶点 在足细胞内，并确定我们拥有的表型潜在的转录后果 观察到的。这些关于EBF1在肾脏发育中的作用的观察最初是由 申请人，杰基·A·弗雷茨博士。她有生物化学和分子生物学的背景，专注于 研究多种细胞类型和谱系的转录调控，目前是一个 研究科学家，一个非独立的职位，在Mark Horowitz博士(导师)的指导下工作， 骨免疫学家。在霍洛维茨博士的实验室里，弗雷茨博士在理解 EBF1在成骨细胞和脂肪细胞命运选择机制中的作用及研究 对EBF1在肾脏发育中的作用的研究为Fretz博士提供了一个明确的独立点，以扩展和 成为一名独立调查员。为了实现这一目标，一个由多学科组成的指导委员会 成立的目的是支持弗雷茨博士的进一步培训和最终的独立性。该委员会的成员包括 除主要导师外，还有2名肾科医生、1名肾脏病理学家和1名发育生物学家。弗雷茨医生是 目前位于耶鲁大学，这是唯一适合实现拟议目标的学校，不仅是为了世界- 在那里工作并同意指导申请者的知名教职员工，也是因为有许多 核心设施相互靠近，可供申请者使用。其中包括组织学 实验室，基因组分析中心，一流的肾脏病理设施，小鼠的代谢表型 中心，耶鲁大学还包括由NIDDK资助的奥布莱恩肾脏研究中心，该中心专门研究 与肾功能调查相关的技术的实施和推广。弗雷茨医生的即刻 职业目标是在完成以下培训后，在学术或医疗机构获得终身教职 完成。她的最终职业目标是研究EBF对肾脏细胞命运的转录调控 蛋白质家族。申请者致力于研究肾脏生物学、转录调控和 未来科学家的教育。收到K99/R00培训补助金将有助于实现这些目标 职业目标，并让这位科学家走上自己的独立之路。

7. Project Summary/Abstract The mature metanephros forms though the outgrowth of the ureteric bud into the metanephric mesenchyme which consequently condenses, undergoes mesenchymal to epithelial transition, and fuses to outgrowths of the bud to form the mature nephron. Multiple coordinated signaling pathways, cytokines and transcription factors have been identified as integral to this processes, however we present here our identification of Early B cell Factor 1 (Ebf1) as a completely novel transcription factor that is required for proper glomerular maturation. In the absence of Ebf1 kidneys develop with thinned cortices, reduced glomerular maturation, and nephrogenic blastema that persist into adulthood. The glomeruli that form present with dysfunctional vascularization, crescents, severely effaced podocytes, and these mice exhibit albuminuria and elevated blood urea nitrogen. We believe that Ebf1 is functioning during an intermediate to late stage of podocyte differentiation. This proposal contains two specific aims designed to (1) identify the stage in nephrogenesis in which Ebf1 functions to direct podocyte maturation, (2) identify the direct targets of Ebf1 within the podocyte, and ascertain the transcriptional consequences underlying the phenotype we have observed. These observations for the role of Ebf1 in kidney development were originally made by the applicant, Dr. Jackie A. Fretz. She has background in biochemistry and molecular biology focused on investigation of transcriptional regulation in multiple cell types and lineages, and is currently an Associate Research Scientist, a non-independent position, working under the direction of Dr. Mark Horowitz (mentor), an osteoimmunologist. In Dr. Horowitz's laboratory Dr. Fretz has made substantial progress into understanding the role of Ebf1 in the mechanisms directing cell fate choices of osteoblasts and adipocytes, and investigation of the role of Ebf1 in renal development presents a clear point of independence for Dr. Fretz to branch out and become an independent Investigator. To achieve this goal a multi-disciplinary mentoring committee has been formed to support the further training and eventual independence of Dr. Fretz. This committee includes, in addition to the primary mentor, 2 nephrologists, a renal pathologist, and developmental biologist. Dr. Fretz is currently located at Yale which is uniquely suited to achieve the proposed aims, not only for the world- renowned faculty that work there and have agreed to mentor the applicant, but also because of the numerous core facilities located in close proximity to each other and available to the applicant. These include histology laboratories, genome analysis centers, a first-class renal pathology facility, a mouse metabolic phenotyping center, and Yale also contains an NIDDK funded O'Brien Center for Kidney Research which specializes in performance and dissemination of techniques relevant to investigation of kidney function. Dr. Fretz's immediate career goal is to obtain a tenure-track faculty position at an academic or medical facility after her training is completed. Her ultimate career goals are to investigate transcriptional regulation of renal cell fates by the Ebf family of proteins. The applicant is committed to research into renal biology, transcriptional regulation, and to the education of future scientists. Receipt of the K99/R00 training grant will be instrumental to achieving these career goals and setting this scientist on her own pathway to independence.