The Role of KLF15 as a transcriptional regulator of podocyte differentiation

描述(由申请人提供)：慢性肾脏疾病的主要病因是最初肾小球功能障碍的直接结果。足细胞是肾小球中的上皮细胞。 帮助维持肾滤过屏障。在许多肾小球疾病中，足细胞失去了特定的分化标志、特征性的形态特征以及维持肾小球滤过屏障的功能能力。我们最近研究了Kr�蛋白样因子15(KLF15)在足细胞分化中的作用，KLF15是一种肾脏丰富的普遍存在的转录因子。具体地说，我们发现KLF15基因的整体缺失增加了小鼠足细胞损伤模型中肾脏损伤的易感性。此外，我们还证实了KLF15在人类肾小球疾病如FSGS和HIVAN中的局部表达降低。最后，我们还证实了KLF15是足细胞损伤恢复所必需的。维甲酸(RA)先前已被证明可以减少足细胞分化标志物的丢失，从而减少蛋白尿和改善肾脏疾病。我们已经证明RA诱导的足细胞分化是由KLF15介导的。糖皮质激素(GCs)是治疗多种肾小球疾病的一线免疫抑制治疗药物。与维甲酸类似，GCs也被证明可以保护足细胞免受伤害。其他人已经在KLF15的启动子区域发现了GC反应元件。我们观察到，地塞米松在培养的人足细胞和原代小鼠足细胞中增加了KLF15的表达。此外，在原代培养的足细胞中KLF15的缺失减弱了GC诱导的足细胞分化的增加。结合起来，我们假设KLF15，一个足细胞分化的关键转录调节因子，介导了RA和GCs在肾小球疾病中的肾脏保护作用。为了解决这一假设，我们建议首先确定KLF15是足细胞分化所必需的，使用足细胞特异性基因敲除小鼠和可诱导的足细胞特异性KLF15过表达小鼠模型。其次，我们计划确定KLF15在介导RA和GCs在肾小球疾病中的肾脏保护作用中的作用。最后，我们建议找出KLF15在足细胞分化中的上游调控因子和下游调控因子。拟议研究结果的影响：我们计划确定KLF15的上调是否介导了糖皮质激素和维甲酸在肾小球疾病中的肾脏保护作用。这将为足细胞生物学和病理学提供新的见解，并为治疗提供一个潜在的新靶点。候选人的短期和长期目标：我的短期目标是实现这个研究项目的具体目标，同时我通过参加每周的正式部门研究会议和每月的工作进展会议来继续扩大我对足细胞生物学和疾病的知识。我还将参加美国肾脏学会年度全国会议和两年一次的足细胞会议和FASE B KLF会议，在那里我将接触到肾小球疾病和KLF生物学领域的最新研究。我将继续利用这样的机会分享我的数据，这样我就可以在我的专业发展中受益于我在这个领域的同事的批评。需要进一步培训的理由：我目前的研究项目涉及KLF15在足细胞分化中的作用。有了K08奖，我将有望通过参加石溪大学医学院的研究生课程来扩大我在分子生物学、生物化学和监管网络方面的知识。此外，未来五年来自多学科咨询委员会的进一步指导将是为实现研究独立提供坚实基础的关键。我准备花费75%的专业努力来实现我的研究战略和培训计划中概述的目标。我的长期目标是成为肾脏疾病方面的KLF15专家，特别是在利用分子技术和系统生物学的综合方法来确定肾小球疾病的潜在治疗靶点方面获得坚实的基础。我可以做到这一点 通过完成概述的培训目标和我的“研究战略”的具体目标。此外，当我达到我的研究目标时，我将致力于在同行评议的期刊上发表我的作品，并申请基金会拨款，这些创意可能源于我目前的工作。经过四年的职业发展资助，我计划通过申请R01级别的资金来开始我的独立调查员职业生涯。候选人的职业发展计划和环境：我已经设计了一个多维的培训计划，为我的跨学科研究提案做准备。此外，我的导师(杨博士和何博士)和我已经召集了多学科的专家小组，在一个咨询委员会中服务(利伯塔尔博士、D‘Agati博士、Schl�ndorff博士和Ma’ayan博士)。我们还设计了一个包含4个不同模块的培训课程：1)掌握研究KLF15信号通路的分子技术，2)小鼠肾脏损伤和病理模型，3)足细胞生物学调节网络，以及4)职业发展和拨款撰写技能。

DESCRIPTION (provided by applicant): The primary etiologies of Chronic Kidney Disease are a direct result of initial glomerular dysfunction. Podocytes are epithelial cells in the glomerulus that help maintain the renal filtration barrier. In many glomerular diseases, the podocyte loses specific markers of differentiation, characteristic morphologic features, and the functional capacity to maintain the glomerular filtration barrier. We recently characterized the role of Kr�ppel-Like Factor 15 (KLF15), a kidney-enriched ubiquitous transcription factor, in podocyte differentiation. Specifically, we showed that a global loss of KLF15 increased the susceptibility to kidney injury in murine models of podocyte injury. Furthermore, we confirmed that the local kidney expression of KLF15 is reduced in human glomerular diseases such as FSGS and HIVAN. Finally, we also established that KLF15 is required for recovery from podocyte injury. Retinoic Acid (RA) has previously been shown to attenuate the loss of podocyte differentiation markers and thereby reduce proteinuria and ameliorate kidney disease. We have shown that RA-induced podocyte differentiation is mediated by KLF15. Glucocorticoids (GCs) are the first line of immunosuppressive therapy in the treatment of many glomerular diseases. Similar to Retinoic Acid, GCs have also been shown to protect podocytes from injury. Others have identified GC response elements in the promoter region of KLF15. We observed that dexamethasone increased KLF15 expression in human podocytes and in primary murine podocytes in culture. In addition, a loss of KLF15 in primary podocytes in culture attenuated the increase in GC-induced podocyte differentiation. Combined, we hypothesize that KLF15, a key transcriptional regulator of podocyte differentiation, mediates the renal protective effects of RA and GCs in glomerular disease. To address the hypothesis, we propose to first determine that KLF15 is necessary for podocyte differentiation using podocyte specific knockout mice and inducible, podocyte-specific KLF15 overexpression murine model. Second, we plan to ascertain the role of KLF15 in mediating renal protective effects of RA and GCs in glomerular disease. Finally, we propose to identify the upstream factors regulating KLF15 and downstream factors regulated by KLF15 in podocyte differentiation. Impact of proposed research outcome: We plan to determine whether the up-regulation of KLF15 mediates the renal protective effect of glucocorticoids and retinoic acid in glomerular disease. This will provide new insight into the podocyte biology and pathology, as well as a potential new target for therapy. Candidate's short-term and long-term goals: My short-term goal is to meet the specific aims of this research project while I continue to expand my knowledge on podocyte biology and disease by attending formal weekly divisional research conferences and monthly Work in Progress meetings. I will also attend the annual American Society of Nephrology national meeting and the biennial Podocyte meeting and FASEB KLF meeting, where I will be exposed to the latest research in the field of glomerular disease and KLF biology. I will continue to take opportunities such as these to share my data so that I can benefit in my professional development from the criticism of my colleagues in our field. Justification of the need for further training: My current research project involves the role of KLF15 in podocyte differentiation. With the K08 Award, I will be expected to expand my knowledge in molecular biology, biochemistry, and regulatory networks by attending graduate level courses at Stony Brook University School of Medicine. In addition, further mentoring from the multidisciplinary advisory committee during the next five years will be crucial in providing a strong foundation towards research independence. I am prepared to spend 75% of my professional effort towards reaching the goals outlined in my research strategy and training plan. My Long-term goal is to be an expert in KLF15 in kidney disease, specifically to gain a strong foundation in utilizing an integrative approach of molecular techniques and systems biology to identify potential therapeutic targets in glomerular disease. I can achieve this by completing the outlined training goals and the specific aims of my "research strategy." In addition, as I meet my research goals, I will work on publishing my work in peer-reviewed journals and apply for foundation grants with original ideas that may stem from my current work. After four years of support from the career-development grant, I plan to begin my career as an independent investigator by applying for R01 level funding. Candidate's career development plan and environment: I have designed a multidimensional training plan to prepare me for my interdisciplinary research proposal. In addition, my mentors (Dr. Yang and Dr. He) and I have assembled multi-disciplinary panel of experts to serve on an advisory committee (Dr. Lieberthal, Dr. D'Agati, Dr. Schl�ndorff, and Dr. Ma'ayan). We have also devised a training curriculum encompassing 4 distinct modules: 1) Mastering molecular techniques to study the KLF15 signaling pathway, 2) Murine models of kidney injury and pathology, 3) Regulatory Networks in podocyte biology, and 4) Career development and grant writing skills.