Genetic Targets of Hypertension End Organ Damage

高血压终末器官损伤的遗传靶标

• 批准号: 10198017
• 负责人: MICHAEL R GARRETT
• 金额: $ 38.75万
• 依托单位: UNIVERSITY OF MISSISSIPPI MED CTR
• 依托单位国家: 美国
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-09-06 至 2023-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10198017
• 关键词: Actins; Age; Albumins; Alleles; Animal Model; Animals; Blood Pressure; Candidate Disease Gene; Cardiovascular system; Cell Adhesion; Cell Line; Cell physiology; Cells; Cellular Morphology; Chromosomes; Chronic; Chronic Kidney Failure; Complex; Congenic Strain; Cytoskeletal Modeling; Dahl Hypertensive Rats; Data; Development; Diagnostic; Dialysis procedure; Exhibits; Exons; Fibrosis; Fluorescein-5-isothiocyanate; Functional disorder; Gene Expression; Genes; Genetic; Genetic Variation; Genetic study; Guanine Nucleotide Exchange Factors; Guanosine Triphosphate; Haplotypes; Health; Human; Hypertension; In Vitro; Inbred SHR Rats; Injury; Injury to Kidney; Introns; Kidney; Kidney Diseases; Kidney Failure; Kidney Transplantation; Knock-out; Lead; Link; Medical Care Costs; Medical center; Mississippi; Modeling; Mus; Organ; Pathway interactions; Permeability; Pharmaceutical Preparations; Play; Population Control; Predisposing Factor; Prevention; Proteinuria; Rattus; Renal function; Resistance; Risk; Risk Factors; Role; Signal Transduction; Sodium Chloride; Stress Fibers; Study models; Testing; Therapeutic; Tubular formation; United States; Universities; Variant; Vascular Diseases; Work; age group; arteriole; blood pressure regulation; cell motility; congenic; cytokine; economic impact; genetic variant; genetically modified cells; genomic locus; hemodynamics; high salt diet; improved; in vivo; kidney dysfunction; knock-down; new therapeutic target; podocyte; positional cloning; promoter; protein expression; protein function; rho; salt sensitive; tool; transplantation therapy; uptake; vascular injury

Project Summary Chronic kidney disease (CKD) is seen in all age groups, impacts more than 30 million people, and is associated with significant medical care costs in the United States. A critical barrier exists in understanding genetic factors that predispose people to hypertensive CKD as well as a lack of therapeutics that act to delay onset and/or progression of kidney dysfunction. The Dahl salt-sensitive (SS) rat is a widely studied model of hypertension that develops kidney injury and progressive decline in kidney function. Through positional cloning, Arhgef11, a Rho guanine nucleotide exchange factor, was implicated in kidney injury exhibited by the SS rat. ARHGEF11 catalyzes the exchange of GDP for GTP, thereby activating RhoA. RhoA-GTP then plays a pivotal role in several pathways that regulate a number of cell functions, including actin cytoskeletal organization, cell adhesion, cell motility, and gene expression. The study of an SS-Arhgef11-congenic model, which substitutes the S allele with that of the SHR (reduced expression/activity), demonstrated significantly decreased proteinuria, tubulointerstitial injury/fibrosis, and improved renal hemodynamics compared to the SS rat. The study of SS rat primary proximal tubules cells demonstrated increased expression of Arhgef11, activation of Rho-ROCK, and decreased uptake of FITC-albumin compared to the SS-Arhgef11-congenic. Conversely, knockdown of Arhgef11 in cell-lines resulted in reduced RhoA activity, decreased activation of Rho-ROCK pathway and less stress fiber formation versus control upon stimulation with TGFβ1 (profibrotic cytokine). In total, the animal and in vitro studies suggest that chronic activation of RhoA pathways by ARHGEF11 could have a significant impact on kidney injury. Thus, our central hypothesis is that allelic variants in Arhgef11 exhibited by the SS rat results in chronic dysregulation of Rho pathways, changes in proximal tubule cell morphology and function, and culminates in kidney injury and decline in kidney function. The specific aims of the proposal are to: (1) investigate the role of Arhgef11 in renal injury, renal hemodynamics, and blood pressure using animal models that augment the expression or knockout Arhgef11 (SS- Arhgef11-/-); (2) study the involvement of Arhgef11 in proximal tubule cells using primary cells and genetically modified cell- lines; and (3) investigate the role of specific Arhgef11 genetic variants/haplotypes (in rat and humans) responsible for altered expression/protein function and subsequent activation of Rho-ROCK. In summary, the successful completion of the proposed project will lead to a better understanding of the role of genetics in hypertensive CKD, the influence of factors that complicate kidney disease, and potential new therapeutic targets.

项目摘要 慢性肾脏疾病(CKD)见于所有年龄段，影响3000多万人，而且 与美国的巨额医疗费用有关。在理解上存在一个关键的障碍 易患高血压慢性肾脏病的遗传因素以及缺乏延迟作用的治疗方法 肾功能障碍的发病和/或进展。Dahl盐敏感(SS)大鼠是一种被广泛研究的 出现肾损伤和肾功能进行性下降的高血压。直通位置 克隆，Arhgef11，一种Rho鸟嘌呤核苷酸交换因子，被认为与肾脏损伤有关 SS大鼠。ARHGEF11催化GDP交换为GTP，从而激活RhoA。然后，RhoA-GTP播放一个 在多种调节细胞功能的通路中起关键作用，包括肌动蛋白细胞骨架 组织、细胞黏附、细胞运动和基因表达。SS-Arhgef11-同源模型的研究 将S等位基因替换为自发性高血压病(表达/活性降低)，显示显著 与SS相比，减少了蛋白尿、肾小管间质损伤/纤维化，并改善了肾脏血流动力学 老鼠。对SS大鼠原代近端小管细胞的研究表明，Arhgef11的表达增加， 与SS-Arhgef11-同源基因相比，Rho-ROCK被激活，FITC-白蛋白摄取减少。 相反，在细胞系中敲除Arhgef11会导致RhoA活性降低，RhoA活性降低， 转化生长因子β-1刺激下的Rho-Rock途径和较小应力纤维的形成与对照 细胞因子)。总之，动物和体外研究表明，RhoA通路的慢性激活通过 ARHGEF11可能对肾脏损伤有重大影响。因此，我们的中心假设是等位基因变异 在SS大鼠表现出的Arhgef11导致Rho通路慢性失调，近端的变化 肾小管细胞的形态和功能，并最终导致肾脏损伤和肾功能下降。这个 该提案的具体目的是：(1)研究Arhgef11在肾脏损伤、肾血流动力学、 使用增强表达或敲除Arhgef11(SS-Arhgef11-/-)的动物模型观察血压； (2)利用原代细胞和转基因细胞研究Arhgef11对近曲小管细胞的影响。 以及(3)研究特定的Arhgef11基因变异/单倍型(在大鼠和人类中)的作用。 负责Rho-ROCK的表达/蛋白功能的改变和随后的激活。总而言之， 拟议项目的成功完成将使人们更好地理解遗传学在 高血压慢性肾脏病、合并肾脏疾病的因素的影响和潜在的新治疗方法 目标。

项目成果

Estimation of Nephron Number in Whole Kidney using the Acid Maceration Method.

使用酸浸渍法估计整个肾脏中的肾单位数。

• DOI: 10.3791/58599
• 发表时间: 2019
• 期刊: Journal of visualized experiments : JoVE
• 作者: Peterson,SarahM;Wang,Xuexiang;Johnson,AshleyC;Coate,IanD;Garrett,MichaelR;Didion,SeanP
• 通讯作者: Didion,SeanP