Role of claudin-2 in Calcium Homeostasis and Kidney Stone Disease

Claudin-2 在钙稳态和肾结石疾病中的作用

基本信息

批准号：
10020951
负责人：
Alan S Yu
金额：
$ 43.71万
依托单位：
UNIVERSITY OF KANSAS MEDICAL CENTER
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：
2019-09-18 至 2024-08-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10020951
关键词：
Affect Attention Back Biological Assay Calcium Cations Colon Crystallization Data Defect Deposition Development Disease Distal Frequencies Gene Proteins Genes Genetic Polymorphism Genotype Goals Henle&apos s loop Homeostasis Human Intercellular Junctions Intestinal Secretions Intestines Ion Channel Kidney Kidney Calculi Knockout Mice Lead Limb structure Lithium Mediating Micropuncture Modeling Mus Nature Nephrocalcinosis Nephrolithiasis Papillary Pathogenesis Pathogenicity Pathway interactions Patients Permeability Phenotype Population Preparation Proteins Proximal Kidney Tubules Recording of previous events Renal tubule structure Risk Risk Factors Role Route Site Testing Thinness Tight Junctions Tissues Tracer Urinary Calculi Urine Western Blotting calcium excretion cohort conditional knockout exosome genetic variant hypercalciuria insight intestinal epithelium novel novel therapeutics population based protein expression radiotracer renal calcium sex thiazide urinary volunteer

项目摘要

PROJECT SUMMARY/ABSTRACT Kidney stones affect 9% of the population and idiopathic hypercalciuria is the major pathogenic risk factor. Our long-term goal is to elucidate the pathogenesis of idiopathic hypercalciuria and develop novel therapies. The renal proximal tubule reabsorbs 70% of filtered calcium, which is believed to occur via the paracellular pathway. Claudin-2 is a paracellular cation channel that is expressed in the proximal renal tubule and in intestinal epithelium. In preliminary studies, we show that claudin-2 knockout mice have renal and absorptive hypercalciuria, leading to severe papillary nephrocalcinosis. Moreover, we find that claudin-2 gene variants are associated with kidney stone disease in humans. We hypothesize that claudin-2 mediates calcium reabsorption in the proximal tubule and calcium secretion in the colon. Loss of claudin-2 increases calcium delivery to the loop of Henle, and predisposes to inner medullary calcium deposition and hence kidney stone disease. The specific aims to test this hypothesis are: (1) Test whether claudin-2 mediates paracellular calcium reabsorption in the renal proximal tubule. We will use tubule micropuncture of claudin-2 global knockout mice, determine the contribution of the proximal tubule with kidney-specific conditional knockout mice, test the role of claudin-2 in the hypocalciuric effect of thiazides, and explore the effect of sex. (2) Test whether claudin-2 mediates intestinal secretion of calcium. We will generate intestine-specific claudin-2 knockout mice and perform tracer flux assays in everted intestinal sacs and Ussing chamber preparations. (3) Test whether human claudin-2 gene variants and protein expression are associated with urine calcium and kidney stones. We will conduct a gene association study in 3 U.S. population-based cohorts to test the association of claudin-2 gene polymorphisms with a history of kidney stones and calcium excretion. In a separate cohort of kidney stone formers and matched normal volunteers, we will test the association of claudin-2 protein abundance in urinary exosomes with hypercalciuric kidney stone disease.

项目摘要/摘要肾结石影响9％的人口，特发性高钙尿症是主要的致病风险因素。我们的长期目标是阐明特发性高钙尿液的发病机理并发展出新的疗法。这肾脏近端小管重新吸收了70％的过滤钙，据信这是通过细胞细胞途径发生的。 claudin-2是一个细胞细胞阳离子通道，在近端肾小管和肠道中表达上皮。在初步研究中，我们表明Claudin-2敲除小鼠具有肾脏和吸收性高钙尿，导致严重的乳头状肾球藻病。而且，我们发现claudin-2基因变体是与人类的肾结石有关。我们假设Claudin-2介导钙的重吸收在结肠中的近端小管和钙分泌中。 Claudin-2的损失将钙的递送增加到 Henle的环，易于内部髓质钙沉积，因此肾脏疾病。这检验该假设的具体目的是：（1）测试Claudin-2是否介导细胞细胞钙的重吸收在肾脏近端小管中。我们将使用claudin-2全局敲除小鼠的小管微孔，确定近端小管对肾脏特异性条件敲除小鼠的贡献，测试Claudin-2在噻嗪类药物的低钙化作用，并探索性别的作用。（2）测试Claudin-2是否介导肠道钙的分泌。我们将生成特定肠道特异性的claudin-2敲除小鼠并执行示踪剂测定在肠道囊和使用室内准备工作中。（3）测试人类claudin-2基因变体是否蛋白质表达与尿钙和肾结石有关。我们将进行基因关联在3个美国基于人群的队列中研究Claudin-2基因多态性与历史的关联肾结石和钙排泄。在另一批肾结石组中，并匹配正常志愿者，我们将测试泌尿外泌体中Claudin-2蛋白丰度与高钙尿素的关联肾脏石材疾病。