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Defective flow-dependent tubule transport in the pathogenesis of kidney disease

肾脏疾病发病机制中的血流依赖性肾小管运输缺陷

基本信息

批准号：
10310442
负责人：
Tong Wang Wang
金额：
$ 37.7万
依托单位：
YALE UNIVERSITY
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：
2019-02-01 至 2023-11-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10310442
关键词：
Acids Aneurysm Animal Disease Models Apical Architecture Blood Vessels Calcium Cations Cells Cyst Cystic kidney DNA Sequence Alteration Data Defect Development Distal Dopamine Dopamine Antagonists Dopamine Receptor Electrolyte Balance Endocytosis Endoplasmic Reticulum Equilibrium Excretory function Family Feedback Fluid Balance Glomerular Filtration Rate Growth Hydrostatic Pressure Impairment Kidney Kidney Diseases Knockout Mice Liquid substance Measures Mediating Methodology Methods Modeling Mus Mutant Strains Mice Mutation Na(+)-K(+)-Exchanging ATPase Natriuresis Nephrons Null Lymphocytes PKD2 protein Pathogenesis Patients Permeability Phenotype Physiological Play Polycystic Kidney Diseases Potassium Prevention Proton-Translocating ATPases Regulation Renal clearance function Renal tubule structure Role Ryanodine Receptor Calcium Release Channel Signal Transduction Sodium Sodium Chloride Surface TRP channel Testing Tubular formation Variant Work absorption conditional knockout glomerular filtration immunocytochemistry improved in vivo inhibitor kidney dysfunction kidney preservation mathematical model mutant mouse model novel novel therapeutics preservation pressure prevent protein intake receptor renal damage shear stress trafficking

项目摘要

Summary The scientific premise of the proposed work is that defective flow-dependent proximal tubule transport may be instrumental in the development and progression of renal dysfunction, a notable example being polycystic kidney disease (PKD). Flow-dependent transport underlies glomerulotubular balance (GTB), whose physiologic importance has been appreciated in normal fluid and electrolyte balance. Whether impaired GTB predisposes to renal damage before GFR is reduced (such as renal cyst formation), has not been studied. Our hypothesis is that episodic increases in kidney tubule hydrostatic pressure promote the creation and growth of renal cysts. This is analogous to the role of arterial pressure in creating vascular aneurysms. There are two control mechanisms, which serve to mitigate the swings in tubule pressure that accompany increases in glomerular filtration (GFR), namely tubuloglomerular feedback and glomerulotubular balance. A mathematical model estimates that with a 50% increase in GFR, impaired GTB increases distal nephron flow, and provokes sharp increases pressure by about 40% in both proximal and distal tubule. This role of GTB, to mitigate GFR- dependent changes of tubule pressure, has never been examined experimentally. During the past 15 years, we have demonstrated that IP3 receptor-mediated intracellular Ca2+ signaling plays a critical role in GTB. Polycystin-2 (PC2) is a nonselective calcium permeable cation channel belonging to the Transient Receptor Potential (TRP) channel family and functions as a Ca2+ channel in the endoplasmic reticulum (ER). Mutations of PC2 abolished the IP3-induced calcium release from the ER. Our preliminary data show a) defective GTB in Pkd2 mutant mice before any renal cysts are formed; and b) Dopamine receptor (DA1) antagonist improves tubule sensitivity to flow and also reduces renal cyst formation in Pkd2 KO mouse, suggesting a new therapeutic method to treat renal disease. In the proposed work, mathematical modeling, renal clearance, microperfusion, immunocytochemistry, and measuring renal tubular pressure in vivo will be used. Hypotheses will be studied in novel nephron-specific conditional knockout PKD animal models, and in PKD null cells to test whether: 1) GTB stabilizes kidney tubule hydrostatic pressure during variations of GFR. This limits tubule distention during GFR elevation, and thus acts to slow cyst formation in Pkd2 KO mice. 2) Inhibition of Na/H- exchanger 3 (NHE3) endocytosis by a DA1 antagonist, increases proximal tubule transporter flow sensitivity, and prevents cyst formation in Pkd2 KO mice. 3) Flow-stimulated NHE3 and/or Na+/K-ATPase trafficking is abrogated in Pkd2 null cells and is similar to blocking the IP3 receptor in WT cells. Inhibition of NHE3 endocytosis by DA1 inhibitor and/or by increasing Ca2+ release from the ER restores the flow-sensing in Pkd2 null cells.

总结这项工作的科学前提是，有缺陷的流量依赖性近端小管运输可能是有助于肾功能不全的发展和进展，一个值得注意的例子是多囊肾脏疾病（PKD）。流量依赖性转运是肾小球肾小管平衡（GTB）的基础，其生理学特性已经认识到正常体液和电解质平衡的重要性。GTB受损是否容易肾损害前GFR降低（如肾囊肿形成），尚未研究。我们的假设肾小管静水压力的间歇性增加促进了肾囊肿的形成和生长。这类似于动脉压在形成血管动脉瘤中的作用。有两个控制这些机制有助于减轻伴随肾小球压力增加的小管压力波动，肾小球滤过率（GFR），即管球反馈和肾小球肾小管平衡。数学模型估计GFR增加50%，受损的GTB增加远端肾单位流量，并引起急剧的增加近端和远端小管的压力约40%。GTB的作用是减轻GFR- 肾小管压力的依赖性变化，从未被实验研究过。在过去的15年里，我们已经证明IP 3受体介导的细胞内Ca 2+信号传导在GTB中起关键作用。多囊蛋白-2（PC 2）是一种非选择性钙离子通道，属于瞬时受体 TRP通道是内质网（ER）中的钙通道。突变 PC 2可抑制IP 3诱导的ER钙释放。我们的初步数据显示：a）GTB存在缺陷， Pkd 2突变小鼠在任何肾囊肿形成之前;和B）多巴胺受体（DA 1）拮抗剂改善肾小管对流量的敏感性，也减少了Pkd 2 KO小鼠肾囊肿的形成，这表明一种新的治疗肾病的方法。在拟议的工作中，数学建模，肾清除率，将使用微灌注、免疫细胞化学和测量体内肾小管压力。假设将在新的肾单位特异性条件性敲除PKD动物模型中进行研究，并在PKD无效细胞中进行测试是否：1）GTB在GFR变化期间稳定肾小管静水压力。这限制了小管在GFR升高过程中，Pkd 2基因敲除小鼠的囊肿扩张，从而减缓囊肿形成。2)抑制Na/H- 通过DA 1拮抗剂的内吞作用，增加近端小管转运蛋白流动敏感性，并防止Pkd 2 KO小鼠中的囊肿形成。3)流动刺激的NHE 3和/或Na+/K-ATP酶运输是在Pkd 2缺失细胞中被消除，并且类似于在WT细胞中阻断IP 3受体。抑制NHE 3 DA 1抑制剂的内吞作用和/或通过增加ER的Ca 2+释放恢复了Pkd 2中的流动敏感空细胞

项目成果

期刊论文数量（15）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

Regulation of ENaC trafficking in rat kidney.

DOI：
10.1085/jgp.201511533
发表时间：
2016-03
期刊：
The Journal of general physiology
影响因子：
0
作者：
Frindt G;Gravotta D;Palmer LG
通讯作者：
Palmer LG

The Concise Guide to PHARMACOLOGY 2015/16: Overview.

DOI：
10.1111/bph.13347
发表时间：
2015-12
期刊：
British journal of pharmacology
影响因子：
7.3
作者：
Alexander SP;Kelly E;Marrion N;Peters JA;Benson HE;Faccenda E;Pawson AJ;Sharman JL;Southan C;Buneman OP;Catterall WA;Cidlowski JA;Davenport AP;Fabbro D;Fan G;McGrath JC;Spedding M;Davies JA;CGTP Collaborators
通讯作者：
CGTP Collaborators

Potassium Channelopathies and Gastrointestinal Ulceration.