Lipid Rafts: Mechanosensors of the distal nephron

脂筏：远端肾单位的机械传感器

• 批准号: 10552548
• 负责人: RAJEEV ROHATGI
• 金额: --
• 依托单位: JAMES J PETERS VA MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-10-01 至 2025-12-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10552548
• 关键词: ATP-Binding Cassette Transporters; Ablation; Active Biological Transport; Adult; Affect; Amino Acids; Apolipoprotein E; Apolipoproteins; Apoptosis; Atherosclerosis; Automobile Driving; Avidity; Blood Pressure; Cardiovascular system; Cell Nucleus; Cells; Ceramides; Cholesterol; Cilia; Clinical; Complex; Consensus Sequence; Data; Development; Diet; Dinoprostone; Disease; Distal; Duct (organ) structure; Electrophysiology (science); Environmental Risk Factor; Epidemiology; Epithelium; Essential Hypertension; Excess Mortality; Excretory function; Functional disorder; Genetic; Genetic Polymorphism; High Density Lipoproteins; Human; Hypertension; Inflammation; Inflammatory; Investigation; K ATPase; Kidney; Kidney Diseases; Knock-out; Lead; Length; Ligands; Link; Lipid Peroxidation; Lipid Peroxides; Liquid substance; Low-Density Lipoproteins; Mediating; Membrane Microdomains; Methods; Mitochondria; Molecular; Mus; Mutation; NOS1 gene; NOS3 gene; Natriuresis; Natriuretic Factors; Nephrons; Organ; Outcome; Oxidative Stress; P2Y2 receptor; Pathway interactions; Phenotype; Physiological; Population; Pre-Eclampsia; Prognosis; Proteins; Repression; Research; Resistance; Resistant Hypertension; Respiration; Risk; Risk Factors; SR-BI receptor; Serum; Signal Transduction; Sodium; Sodium Chloride; Sphingomyelinase; Sphingomyelins; Stress; Systemic blood pressure; Systemic hypertension; TLR2 gene; TLR4 gene; Tangier Disease; Testing; Tissues; Tubular formation; Variant; absorption; autocrine; cyclooxygenase 2; density; design; dietary; epithelial Na+ channel; inflammatory marker; knock-down; mortality; mouse model; novel; paracrine; pharmacologic; premature atherosclerosis; recruit; response; risk variant; salt sensitive hypertension; saluretic; shear stress; symporter; transcriptome sequencing; urinary

Hypertension (HTN) affects millions of adults in the U.S and leads to end organ damage. This study is designed to test whether dysregulation of the cholesterol (chol) efflux pathway affects sodium (Na) dependent rise in systemic blood pressure (BP), both of which are risk factors for mortality. The chol efflux pathway is comprised of two pathways, (1) facilitated chol transport or (2) the active transport pathway regulated by ATP-binding cassette (ABC) transporters, ABC transporter A1 (ABCA1) and ABC transporter G1 (ABCG1). ABCA1 polymorphisms, that repress chol efflux, are associated with HTN while non-functional mutations of ABCA1 cause Tangiers disease with early atherosclerosis. High Na diets increase tubular flow that stimulate paracrine pathways to suppress Na absorption and, thus, enhance Na excretion; as a corollary, targeted deletion of flow-mediated autocrine-paracrine pathways enhance renal Na avidity and HTN. Renal prostaglandin E2 (PGE2) knock out (KO) causes Na sensitive HTN. Moreover, increases in tubular flow induce cyclooxygenase-2 (COX2) activity/protein and collecting duct (CD) PGE2 release to inhibit epithelial Na channel (ENaC). The effects of flow on COX2 and PGE2 are muted in CDs isolated from mice fed a 1% chol vs. no chol diet. The chol content from chol fed mice doubles versus controls. ABCA1 ablation in CDs, increases CD chol, stimulates ENaC, reduces urinary ATP and raises BP. ABCA1 ablation also predisposes to an inflammatory renal microenvironment. Increases of LR free chol enhance ligand-dependent toll-like receptor (TLR) 4 signaling which is linked to tubular Na transport. Elevated LR free chol recruit TLR4 to LRs, increasing LR TLR4 density, to augment signaling. Transepithelial Na transport stimulates Na/K-ATPase mediated ATP demand driving mitochondrial oxidative respiration, oxidative stress, lipid peroxidation and ferroptosis. TLR4 is stimulated by stress induced ligands including lipid peroxides leading to an inflammatory and Na avid phenotype. Thus, we hypothesize that excess tubular PM/LR chol content in ABCA1 deficient tubules will induce Na avidity and inflammation due to muted flow mediated natriuretic pathways, primed TLR4 responses, and transport dependent oxidative respiration and stress to form the Na sensitive phenotype. This will be tested in the specific aims (SAs): SA1. To evaluate whether depletion or deletion of tubular ABCA1 expression contributes to the development of renal Na avidity and HTN SA1a. Test whether tubular ABCA1 ablation is sufficient or dietary chol is necessary to induce Na sensitivity. SA1b. Determine whether serum LDL level modifies the Na avidity by crossing ABCA1fl/fl (ABCA1 FF) mice into the apolipoprotein E (APOE) deficient mouse SA2. Test whether chol affects PM/LR function to repress flow mediated Na excretory pathways and augment TLR4 inflammatory signaling to promote anti-natriuresis and HTN SA2a. Test whether chol incorporation into LRs directly enhances Na transport and represses FSS induced natriuretic factors to augment Na absorption using molecular, physiologic and electrophysiologic methods. SA2.b Determine whether altering the PM chol, and specifically, LR chol effects TLR4 density and activation, and, hence, inflammatory markers and transepithelial Na transport. SA2.c Test whether pharmacologic PM chol depletion reverses Na sensitivity and inflammation. SA3. Greater rates of Na transport in ABCA1 deficient mice increase oxidative respiration and stress that activates the ferropotic pathway, based on single nuclei RNAseq (snRNAseq) data. SA3a. Determine whether greater Na/K-ATPase activity is driving greater mitochondrial respiration and oxidative stress in ABCA1 deficient kidneys. SA3b. Characterize if increased mitochondrial respiration and stress augments ferroptosis in tubular epithelia.

高血压（HTN）影响美国数百万的成年人，并导致最终器官损害。这项研究是 设计用于测试胆固醇（CHOL）外排途径的失调是否影响钠（NA）依赖 全身血压（BP）的升高，这都是死亡率的危险因素。 CHOL外排途径由两种途径组成，（1）促进CHOL转运或（2）主动 由ATP结合盒（ABC）转运蛋白，ABC转运蛋白A1（ABCA1）和 ABC转运蛋白G1（ABCG1）。 ABCA1多态性（抑制Chol外排）与HTN有关 ABCA1的非功能突变会导致早期动脉粥样硬化。 高Na饮食会增加管状流动，从而刺激旁分泌途径以抑制Na吸收和 因此，增强了Na排泄；作为推论的，有针对性的流量介导的自分泌 - 核心途径的缺失 增强肾脏NA的自然和HTN。肾脏前列腺素E2（PGE2）敲出（KO）引起Na敏感 htn。此外，肾小管流动的增加诱导环氧酶-2（COX2）活性/蛋白质并收集导管 （CD）PGE2释放以抑制上皮NA通道（ENAC）。流对Cox2和PGE2的影响被静音 在从喂食1％Chol与无chol饮食的小鼠中分离出的CD中。 Chol Fed Mice的CHOL含量双打与 控件。 CD中的ABCA1消融，增加CD CHOL，刺激ENAC，减少ATP并增加BP。 ABCA1消融还易于炎症性肾脏微环境。 LR免费增加 CHOL增强了依赖配体的Toll样受体（TLR）4信号传导，该信号传导与管状Na转运有关。 升高LR的lr Chol募集TLR4至LRS，增加了LR TLR4密度，以增强信号传导。 transepithial Na转运刺激Na/K-ATPase介导的ATP需求驱动线粒体氧化呼吸， 氧化应激，脂质过氧化和铁铁作用。 TLR4受到应力诱导的配体（包括脂质）的刺激 过氧化物导致炎症和NA狂热的表型。因此，我们假设多余的管状 ABCA1缺陷小管中的PM/LR CHOL含量会引起NA的炎症和炎症 流动介导的亚钠途径，底漆的TLR4反应和依赖于转运的氧化 呼吸和压力形成NA敏感表型。这将在特定目的（SAS）中进行测试： SA1。评估管状ABCA1表达的耗竭或缺失有助于 肾脏NA的发展和HTN的发展 sa1a。测试管状ABCA1消融是否足够或饮食中的CHOL来诱导NA敏感性。 sa1b。确定血清LDL水平是否通过将ABCA1FL/FL（ABCA1 FF）小鼠跨入NA的自然 载脂蛋白E（APOE）缺乏鼠标 SA2。测试CHOL是否影响PM/LR功能以抑制流动介导的Na排泄途径和 增强TLR4炎症信号传导，以促进抗催化性和HTN sa2a。测试CHOL掺入LRS是否直接增强NA转运并抑制FSS诱导 使用分子，生理和电生理方法来增强Na吸收的纳地尿素因子。 SA2.b确定是否改变了PM Chol，特别是LR CHOL效应TLR4密度和激活， 因此，炎症标志物和旋转的NA运输。 SA2.C测试药理学PM CHOL耗竭是否会逆转NA敏感性和炎症。 SA3。 ABCA1缺乏小鼠中NA转运的速率较高，增加了氧化呼吸和应力 基于单核RNASEQ（SNRNASEQ）数据，激活了螺母途径。 SA3A。确定更大的Na/k-ATPase活性是否正在推动更大的线粒体呼吸和 ABCA1缺乏肾脏中的氧化应激。 SA3B。表征如果增加的线粒体呼吸和压力增加了肾小管上皮中的铁质吞噬作用。