Proximal tubule endocytosis in normal and nephrotic kidneys

正常和肾病肾脏的近端小管内吞作用

基本信息

批准号：
10132740
负责人：
Ora A Weisz
金额：
$ 45.21万
依托单位：
UNIVERSITY OF PITTSBURGH AT PITTSBURGH
依托单位国家：
美国
项目类别：
财政年份：
2019
资助国家：
美国
起止时间：
2019-04-16 至 2023-03-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10132740
关键词：
Acute Adaptor Signaling Protein Address Albumins Animal Model Apical Apoptosis Binding Blood Cell Culture System Cell Culture Techniques Cell membrane Cell physiology Cells Chronic Chronic Kidney Failure Complex Cultured Cells Cytoplasmic Tail Development Didelphidae Disabled Homolog 2 Protein Disease Endocytosis Enzymes Excretory function Filtration Glomerular Filtration Rate Human Impairment In Vitro Individual Injury Ion Transport Ions Kidney Kidney Diseases Knockout Mice LDL-Receptor Related Protein 2 Ligands Link Lipids Liquid substance Mediating Modeling Molecular Morphology Mus Nephrons Pathologic Pathway interactions Plasma Plasma Proteins Predisposition Proteins Proteinuria Proximal Kidney Tubules Recovery Renal function Research Role Sex Differences Signal Transduction Surface Testing Therapeutic Time Transmembrane Domain Tubular formation Urine Variant Water Work blood pressure regulation combat cytotoxic glomerular filtration in vivo intrinsic factor-cobalamin receptor kidney cell kidney cortex mouse model preservation prevent protein expression receptor response shear stress therapy design trafficking transcriptome sequencing uptake urinary

项目摘要

Abstract A major function of cells linking the proximal tubule (PT) of the kidney is to recover proteins that escape the glomerular filtration barrier to maintain a protein-free urine. Apical endocytosis in PT cells is acutely modulated by changes in fluid shear stress (FSS), presumably to enable efficient protein uptake over normal variations in glomerular filtration rate (GFR). The large multiligand receptors megalin and cubilin/amnionless (CUBAM) are expressed at the apical surface of PT cells and mediate the internalization of >50 different plasma proteins. Despite the critical role of the PT in reclaiming proteins from the ultrafiltrate, we know surprisingly little about how the cells lining this segment accommodate variations in filtered load to maintain a protein free urine. Fundamental issues, including how the robust PT apical endocytic pathway is developed and maintained, the individual role of megalin and CUBAM receptors in albumin uptake, how PT cells respond to changes in albumin concentration or tubular flow rate, and the fate of internalized albumin remain controversial. We have developed a new cell culture model that recapitulates morphological and functional features of PT cells in vivo necessary for efficient and rapidly modulated apical endocytosis of albumin. We will use these cells in conjunction with studies in mouse models to address the following questions about how PT cells respond to normal and pathologic variations in flow and filtered protein load: 1) How do PT cells develop and maintain a high capacity apical endocytic pathway? 2) How do megalin and CUBAM contribute to albumin uptake under normal and nephrotic conditions? 3) How does the PT respond endocytically to acute changes in GFR? and 4) How does endocytosis contribute to cytotoxic responses of PT cells during albumin overload?

抽象的连接肾脏近端小管 (PT) 的细胞的主要功能是回收逃逸的蛋白质肾小球滤过屏障维持无蛋白质尿液。 PT 细胞的顶端内吞作用是急性的通过流体剪切应力 (FSS) 的变化进行调节，大概是为了实现有效的蛋白质摄取肾小球滤过率 (GFR) 的正常变化。大型多配体受体巨蛋白和 cubilin/amnionless (CUBAM) 在 PT 细胞的顶端表面表达并介导 > 50 种不同血浆蛋白的内化。尽管 PT 在回收蛋白质方面发挥着关键作用从超滤液中，我们对衬在该部分的细胞如何适应的情况知之甚少改变过滤负荷以维持无蛋白质尿液。基本问题，包括如何稳健 PT 顶端内吞途径的发展和维持，巨蛋白和 CUBAM 的各自作用白蛋白摄取受体，PT 细胞如何响应白蛋白浓度或肾小管流量的变化率和内化白蛋白的命运仍然存在争议。我们开发了一种新的细胞培养物该模型概括了 PT 细胞体内有效的形态和功能特征并快速调节白蛋白的顶端内吞作用。我们将结合研究使用这些细胞在小鼠模型中解决以下关于 PT 细胞如何响应正常和流量和过滤蛋白负载的病理变化：1) PT 细胞如何发育并维持高水平顶端内吞途径的能力？ 2) 巨蛋白和 CUBAM 如何促进白蛋白摄取正常情况和肾病情况？ 3) PT 如何对 GFR 的急性变化做出内吞反应？ 4) 在白蛋白超载期间，内吞作用如何促进 PT 细胞的细胞毒性反应？