Use of small molecules that stabilize dynamin rings in podocytopathies

描述（由申请人提供）：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，肾小球肾病就影响了大约2000万人，并且这个数字在过去二十年中大约翻了一番。事实上，与肾脏有关的疾病正在迅速地远离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高度优先的。足细胞是肾小球内的特化细胞，对肾脏超滤至关重要。它们形成足突（FP），高度动态的肌动蛋白为基础的细胞延伸，通过狭缝隔膜连接。大多数形式的蛋白尿和肾病综合征的特征在于，由于肌动蛋白细胞骨架的失调，足细胞FP转化为细胞质带（称为FP消失）。这项建议的工作是基于我们最近鉴定的GTdR动力蛋白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消失，恢复功能性足细胞并改善蛋白尿。我们最近发现，发动蛋白直接调节足细胞中的肌动蛋白细胞骨架。此外，我们已经确定了小分子，促进发动蛋白寡聚成环，这反过来又保护肌动蛋白在足细胞的细胞骨架。在这项拨款申请中，我们在不同的蛋白尿肾病啮齿动物模型中测试了发动蛋白环稳定剂药物逆转FP消失和改善蛋白尿的能力。在具体目标1中，我们测试了发动蛋白药物在蛋白尿肾病的诱导模型中的功效，例如嘌呤霉素氨基糖苷（PAN）肾病的大鼠模型和阿霉素肾病的大鼠模型。在具体目标2中，我们测试了发动蛋白环稳定剂药物在蛋白尿肾病遗传模型中的功效，例如（1）由于表达“功能获得”1-辅肌动蛋白4突变体而导致肌动蛋白细胞骨架失调的小鼠模型;（2）缺乏CD 2AP的小鼠模型。（衔接蛋白参与调节肌动蛋白细胞骨架和足细胞信号）;（3）表达高水平TGF-β 1的转基因小鼠。在具体目标3中，我们研究了环稳定药物是否影响质膜上nephrin的周转。我们的工作有可能确定动力蛋白药物作为治疗蛋白尿肾病的新疗法。 公共卫生相关性：仅在美国，肾小球型肾脏疾病影响约2000万人，并且这个数字在过去二十年中大约翻了一番。在这里，我们建议测试的能力，小分子（药物）的子集，具体目标GTdR发动蛋白，以改善蛋白尿，通过恢复足细胞的结构和功能。不同的药物将在蛋白尿肾病的诱导型和遗传型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.