Use of small molecules that stabilize dynamin rings in podocytopathies

描述(申请人提供)：慢性肾脏疾病的全球流行正在以惊人的速度发展。仅在美国，肾小球疾病就影响了大约2000万人，这个数字在过去20年里大约翻了一番。事实上，与肾脏相关的疾病正在迅速避开目前的治疗选择和资源。因此，发现治疗慢性肾脏疾病的新疗法是当务之急。足细胞是肾小球内的特殊细胞，对肾脏超滤至关重要。它们形成足突(FP)，这是一种高度动态的基于肌动蛋白的细胞延伸，由缝隙横隔膜连接。大多数形式的蛋白尿和肾病综合征的特征是由于肌动蛋白细胞骨架的去调节(称为FP消失)，足细胞FP转化为一条细胞质条带。这项建议中的工作是基于我们最近发现的GTPase Dynamin作为足细胞肌动蛋白动力学的主要调节因子。该实验室的研究表明，动力蛋白功能的保留足以逆转FP的消失，恢复功能性足细胞，并改善蛋白尿。我们最近发现，Dynamin直接调节足细胞中的肌动蛋白细胞骨架。此外，我们已经确定了促进动力蛋白寡聚成环的小分子，这反过来又保护足细胞中的肌动蛋白细胞骨架。在这项拨款申请中，我们测试了动力蛋白环稳定剂药物在不同蛋白尿性肾病啮齿动物模型中逆转FP消失和改善蛋白尿的能力。在具体目的1中，我们测试了Dynamin药物在诱导蛋白尿肾病模型中的疗效，如嘌呤霉素氨基核苷肾病(PAN)大鼠模型和阿霉素肾病大鼠模型。在特定目标2中，我们测试了Dynamin环稳定剂药物在蛋白尿性肾脏疾病遗传模型中的有效性，例如(1)由于Actinin 4突变体的表达而导致肌动蛋白细胞骨架调节错误的小鼠模型；(2)缺乏CD2AP(参与足细胞内肌动蛋白细胞骨架和信号转导的适配器蛋白)的小鼠；(3)高水平表达转化生长因子-1的转基因小鼠。我们的工作有可能确定动力蛋白药物作为治疗蛋白尿肾脏疾病的新疗法。 与公共卫生相关：仅在美国，肾小球型肾脏疾病就影响了大约2000万人，这个数字在过去20年里大约翻了一番。在这里，我们建议测试小分子(药物)亚组的能力，这些小分子(药物)专门针对GTP酶动力蛋白，通过恢复足细胞结构和功能来改善蛋白尿。不同的药物将在蛋白尿性肾病的诱发性和遗传性啮齿动物模型中进行测试。

DESCRIPTION (provided by applicant): The global epidemic of chronic kidney disease is progressing at an alarming rate. In the United States alone, glomerular kidney diseases affect some 20 million people, and this number has roughly doubled in the last two decades. Indeed, kidney-related diseases are rapidly eluding present treatment options and resources. Thus, it is high priority to uncover novel therapeutics to treat chronic kidney diseases. Podocytes are specialized cells within the glomerulus that are essential for kidney ultrafiltration. They form foot processes (FPs), highly dynamic actin-based cellular extensions that are connected by slit diaphragms. Most forms of proteinuria and nephrotic syndrome are characterized by transformation of podocyte FPs into a band of cytoplasm due to de- regulation of the actin cytoskeleton (referred to as FP effacement). The work in this proposal is based on our recent identification of the GTPase dynamin as a major regulator of actin dynamics in podocytes. Studies from this laboratory suggest that preservation of dynamin function is sufficient to reverse FP effacement, restore functional podocytes and ameliorate proteinuria. We have recently shown that dynamin directly regulates the actin cytoskeleton in podocytes. In addition, we have identified small molecules that promote dynamin oligomerization into rings, which in turn protects actin cytoskeleton in podocytes. In this grant application we test the ability of dynamin ring stabilizer drugs to reverse FP effacement and ameliorate proteinuria in different rodent models of proteinuric kidney disease. In Specific Aim 1 we test efficacy of dynamin drugs in inducible models of proteinuric kidney disease such as a rat model of puromycin aminonucleoside (PAN) nephrosis and a rat model of adriamycin nephrosis. In Specific Aim 2 we test efficacy of dynamin ring stabilizer drugs in genetic models of proteinuric kidney diseases such as (1) mouse model in which actin cytoskeleton is mis- regulated due to expression of 'gain of function' 1-actinin 4 mutant; (2) mice lacking CD2AP (adaptor protein involved in regulation of actin cytoskeleton and signaling in podocytes); (3) transgenic mice expressing high levels of TGF-¿1. In Specific Aim 3 we examine whether ring stabilizing drugs effect turnover of the nephrin at the plasma membrane. Our work has potential to identify dynamin drugs as novel therapeutics to treat proteinuric kidney diseases. PUBLIC HEALTH RELEVANCE: In the United States alone, glomerular type of kidney diseases effects some 20 million people, and this number has roughly doubled within the last two decades. Here we propose to test the ability of subset of small molecules (drugs) that specifically target GTPase dynamin to ameliorate proteinuria by restoring podocyte structure and function. Different drugs will be tested in inducible and genetic rodent models of proteinuric kidney diseases.