Role of C1C5 in Endocytosis and NHE3 Trafficking

C1C5 在内吞作用和 NHE3 运输中的作用

• 批准号: 7487971
• 负责人: SANDRA ELIZABETH GUGGINO
• 金额: $ 29.16万
• 依托单位: JOHNS HOPKINS UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-09-01 至 2009-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7487971
• 关键词: ATP phosphohydrolase; Abbreviations; Affect; Albumin Receptors; Albumins; Apical; Appendix; Behavior; Biotinylation; Brush Border; CI-4; Cells; Chloride Channels; Chloride Ion; Chlorides; Clathrin; Cultured Cells; Defect; Dextrans; Disease; Disruption; Down-Regulation; Early Endosome; Endocytosis; Endosomes; Event; Exhibits; Exocytosis; Fanconi Syndrome; Fluorescent Dyes; Glycosuria; Goals; Golgi Apparatus; Half-Life; Horseradish Peroxidase; Human; Immunoelectron Microscopy; Ions; Kidney; Kidney Failure; Knock-out; Knockout Mice; LDL-Receptor Related Protein 2; Label; Lead; Liquid substance; Location; Lysosomes; Mannosidase; Mediating; Membrane; Membrane Transport Proteins; Molecular; Molecular Weight; Monitor; Mus; Mutate; Mutation; Nephrocalcinosis; Nephrolithiasis; Nephrons; Organelles; Outcome; Patients; Phase; Phenotype; Physiologic pulse; Polyuria; Proteins; Proteinuria; Proton-Translocating ATPases; Protons; Proximal Kidney Tubules; Pulse taking; Radiolabeled; Recycling; Research; Research Personnel; Residual state; Role; Role playing therapy; Shunt Device; Surface; Syndrome; System; TGN38 protein; Testing; Tissues; Tracer; Vitamin D-Binding Protein; Wilson disease protein; alanine aminopeptidase; apical membrane; base; basolateral membrane; calcification; cellular microvillus; channel blockers; chromophore; dextran; disease phenotype; gastrointestinal microvillus; hypercalciuria; ileum; inhibitor/antagonist; jejunum; knock-down; late endosome; male; mouse model; mutant; programs; radiotracer; receptor; research study; sodium-phosphate cotransporter proteins; tetramethylrhodamine; trafficking; uptake; voltage

Dent's disease, is a disorder that is characterized by low molecular weight proteinuria, aminoaciduria, glycosuria, polyuria, hyperphosphaturia (Fanconi syndrome) as well as hypercalciuria, nephrocalcinosis, nephrolithiasis. Dent's disease has been established to be caused by mutations of the CICN-5 gene, the product of which is CIC-5 a voltage-gated chloride channel expressed in highest abundance in renal tubules of the proximal nephron. Our preliminary studies in a CICN-5 knockout mouse model, shows that it recapitulates the features of Dent's disease including hypercalciuria, aminoaciduria, glycosuria, low molecular weight proteinuria, renal calcifications, and renal failure. THE PRPOSED STUDY WILL HELP DEFINE THE UNDERLYING MOLECULAR BASIS OF THESE REABSORPTION DEFECTS. Specific aim 1: How do other CIC channels or CIC-5 exchange regulate apical endocytosis in proximal tubule cells? 1 A. Do CIC-3 and/or CIC-4 contribute to the residual acidification and apical endocytosis in the ko cells? 18. Does the over-expression of CIC-3 and CIC-4 restore albumin uptake in CIC-5 ko cells? Does the chloride/proton exchanger activity of CIC-5 in ko cells restore normal albumin uptake? Specific Aim 2: What is the relationship between loss of CIC-5 and the downregulation of megalin in the ko proximal tubule cells? 2A. Is the half-life of megalin shorter in ko versus wt cells? 2B. How is the recycling behavior of megalin altered in ko versus wt cells? 2C. Does endosomal pH, or lack of CIC-5, regulate megalin dynamics? Specific Aim 3. How does the loss of CIC-5 lead to changes in the distribution/activity of NHE3 and other apical transporters? 3A. Is NHE3 activity decreased in the proximal tubule, ileum or jejunum of ko mice? 3B. What are the steady state levels and dynamics of NHE3 in ko proximal tubules cells? 3C. What are the steady state levels and dynamics of NaPi-lla in ko proximal tubule cells? 3D, Does endosomal pH, or lack of CIC-5, regulate NHE3 or NaPi-lla dynamics? The long term goal of this research is to understand how molecular events cause the phenotypical outcomes of Dent's disease.

登特氏病，是一种以低分子蛋白尿、氨基酸尿症、 糖尿症、多尿症、高磷尿症(范可尼综合征)以及高钙尿、肾钙素沉着症、 肾结石。登特氏病已被证实是由CICN-5基因突变引起的， 其产物是CIC-5，一种电压门控氯通道，在肾小管中表达最丰富 近端肾单位。我们在CICN-5基因敲除小鼠模型中的初步研究表明，它 总结了登特氏病的特点，包括高钙尿、氨基酸尿症、糖尿症、低尿症 分子量蛋白尿、肾脏钙化和肾功能衰竭。提出的研究将有所帮助 确定这些重吸收缺陷的潜在分子基础。 具体目标1：其他CIC通道或CIC-5交换如何调节近端的心尖部内吞作用 肾小管上皮细胞？1A.CIC-3和/或CIC-4是否参与了残存的酸化和根尖细胞吞噬作用？ KO细胞？18.CIC-3和CIC-4的过表达是否恢复了CIC-5 KO细胞的白蛋白摄取？会吗？ CIC-5在KO细胞中的氯/质子交换活性恢复正常的白蛋白摄取？具体目标2： CIC-5的缺失与KO近端小管中巨球蛋白的下调有什么关系 细胞？2a。在ko细胞和wt细胞中，megalin的半衰期是否更短？的回收行为如何？ 在ko细胞和wt细胞中，megalin发生了变化？2C。内体pH或缺乏CIC-5是否调节巨蛋白 动力学？具体目标3.CIC-5的缺失如何导致NHE3的分布/活性发生变化 其他心尖转运蛋白呢？3A。近曲小管、回肠或空肠NHE3活性降低吗？ 老鼠？3B。Ko近曲小管细胞中NHE3的稳态水平和动态变化是什么？什么 Ko近曲小管细胞中napi-11a的稳态水平和动态变化吗？ 缺乏CIC-5，调节NHE3或NAPI-ILA动力学？ 这项研究的长期目标是了解分子事件如何导致表型 登特氏病的转归。