Regulation of the mTOR pathway in polycystic kidney disease

多囊肾病中 mTOR 通路的调节

• 批准号: 7246452
• 负责人: Thomas Weimbs
• 金额: $ 27.52万
• 依托单位: UNIVERSITY OF CALIFORNIA SANTA BARBARA
• 依托单位国家: 美国
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-07-15 至 2012-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7246452
• 关键词: Affect; Apical; Apoptosis; Autosomal Dominant Polycystic Kidney; Biological Preservation; C-terminal; Cell Differentiation process; Cells; Chimeric Proteins; Chronic; Cilia; Clinical Trials; Co-Immunoprecipitations; Complex; Cyst; Cystic kidney; Cytoplasmic Tail; Data; Dialysis procedure; Disease; Disease Progression; Dose; Drug usage; Effectiveness; Epithelial Cells; Esthesia; Event; Foundations; Future; Genes; Growth; Hereditary Disease; Human; Immunoblotting; Immunofluorescence Microscopy; Immunosuppression; Investigation; Kidney; Kidney Failure; Kidney Transplantation; Length; Life; MDCK cell; Mediating; Modeling; Mus; Mutation; PKD1 gene; Pathway interactions; Patients; Phospho-Specific Antibodies; Phosphotransferases; Physical Dialysis; Play; Polycystic Kidney Diseases; Preparation; Proteins; Recovery; Recruitment Activity; Regulation; Renal function; Research; Research Personnel; Role; Sampling; Sirolimus; Staging; Testing; Therapeutic immunosuppression; Time; Transplant Recipients; Treatment Protocols; Tuberous sclerosis protein complex; Weight; base; cell growth; design; dosage; fluid flow; genetic regulatory protein; human FRAP1 protein; human TSC1 protein; human TSC2 protein; kinetosome; mTOR Inhibitor; mTOR inhibition; mouse model; novel; polycystic kidney disease 1 protein; research study; size

DESCRIPTION (provided by applicant): Autosomal-dominant (ADPKD) is the most common life-threatening genetic disease. Tuberous Sclerosis Complex (TSC) is 10-times less common than ADPKD. Both diseases are characterized by renal cysts. No treatment is currently available to slow the onset or progression of either disease. We have recently found that polycystin-1 (PC1), the protein affected in ADPKD, interacts with tuberin, the protein affected in TSC, and regulates the activity of the kinase mTOR. mTOR plays an important role in cell growth and proliferation and is known to be inhibited by tuberin. We propose a model in which the C-terminal cytoplasmic tail of PC1 functions to induce the formation of a complex between tuberin and mTOR and other regulatory proteins. The function of this complex is to suppress mTOR activity in normal renal epithelial cells. Our results suggest that mTOR inhibition is regulated by apical fluid flow. We found that mTOR is inappropriately active in the kidneys of ADPKD patients and in mice with polycystic kidneys. Treatment of polycystic kidney mice with the mTOR inhibitor rapamycin results in the dramatic reduction of renal and cyst sizes and in the preservation of kidney function. This strongly suggests that aberrant mTOR activation in ADPKD is critical for renal cyst growth. We now propose to study in detail the mechanism of the suppression of mTOR activity by PC1. In Aim 1, we will investigate the interaction between PC1 and mTOR and identify additional regulatory factors and the subcellular localization of the complex. We will test whether this complex is disrupted in renal cysts. In Aim 2, we will test how fluid flow regulates mTOR activity. In Aim 3, using samples from ADPKD kidneys and a mouse model with a conditionally inactivated PKD1 gene we will characterize which of the known downstream effectors and upstream regulators of mTOR are affected in the disease. In Aim 4, in preparation for possible future clinical trials, we will investigate the effects of rapamycin on the PKD1 mouse model. We will assess dosage and treatment regimens and investigate the effects on proliferation and apoptosis of cystic epithelial cells. These investigations will be important to guide possible future clinical trials. Rapamycin is already a clinically approved drug, used for long-term treatment for immunosuppression in renal transplant patients. Based on our data, we are cautiously optimistic that rapamycin has promise to become the first available treatment to slow the disease progression in ADPKD. Furthermore, results from this research will enhance our understanding of the mechanisms underlying the renal involvement in TSC.

描述（由申请人提供）：常染色体显性遗传病（ADPKD）是最常见的危及生命的遗传病。结节性硬化症 (TSC) 的发病率比 ADPKD 少 10 倍。这两种疾病的特征都是肾囊肿。目前尚无治疗方法可以减缓这两种疾病的发作或进展。我们最近发现 ADPKD 中受影响的蛋白质多囊蛋白-1 (PC1) 与 TSC 中受影响的蛋白质马铃薯蛋白相互作用，并调节激酶 mTOR 的活性。 mTOR 在细胞生长和增殖中发挥重要作用，已知会被马铃薯蛋白抑制。我们提出了一个模型，其中 PC1 的 C 端胞质尾部起到诱导马铃薯蛋白和 mTOR 以及其他调节蛋白之间复合物形成的作用。该复合物的功能是抑制正常肾上皮细胞中的 mTOR 活性。我们的结果表明 mTOR 抑制是由心尖液流调节的。我们发现 mTOR 在 ADPKD 患者和多囊肾小鼠的肾脏中异常活跃。用 mTOR 抑制剂雷帕霉素治疗多囊肾小鼠，可显着减小肾脏和囊肿的大小，并保留肾功能。这强烈表明 ADPKD 中 mTOR 的异常激活对于肾囊肿的生长至关重要。我们现在建议详细研究PC1抑制mTOR活性的机制。在目标 1 中，我们将研究 PC1 和 mTOR 之间的相互作用，并确定其他调节因子和复合物的亚细胞定位。我们将测试该复合物在肾囊肿中是否被破坏。在目标 2 中，我们将测试流体流动如何调节 mTOR 活性。在目标 3 中，使用来自 ADPKD 肾脏的样本和具有条件性失活 PKD1 基因的小鼠模型，我们将表征哪些已知的 mTOR 下游效应器和上游调节器在该疾病中受到影响。在目标 4 中，为了为未来可能的临床试验做准备，我们将研究雷帕霉素对 PKD1 小鼠模型的影响。我们将评估剂量和治疗方案，并研究对囊性上皮细胞增殖和凋亡的影响。这些研究对于指导未来可能的临床试验非常重要。雷帕霉素已经是临床批准的药物，用于肾移植患者免疫抑制的长期治疗。根据我们的数据，我们谨慎乐观地认为雷帕霉素有望成为减缓 ADPKD 疾病进展的第一种可用治疗方法。此外，这项研究的结果将增强我们对 TSC 肾脏受累机制的理解。