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 慢性肾脏病（CKD）见于所有年龄组，影响超过3000万人， 与美国的医疗保健费用有关。一个关键的障碍存在于理解 遗传因素使人们易患高血压CKD以及缺乏治疗方法， 肾功能不全的发作和/或进展。Dahl盐敏感（SS）大鼠是一种广泛研究的盐敏感模型。 高血压导致肾损伤和肾功能进行性下降。通过位置 克隆，Arhgef 11，一种Rho鸟嘌呤核苷酸交换因子，与肾损伤有关， 党卫军老鼠。ARHGEF 11催化GDP交换为GTP，从而激活RhoA。RhoA-GTP然后发挥作用， 在调节许多细胞功能的几个途径中起关键作用，包括肌动蛋白细胞骨架 组织、细胞粘附、细胞运动和基因表达。SS-Arhgef 11-同源模型的研究 用SHR的S等位基因替代S等位基因（表达/活性降低）， 与SS相比，蛋白尿、肾小管间质损伤/纤维化减少，肾血流动力学改善 大鼠对SS大鼠原代近曲小管细胞的研究表明，Arhgef 11的表达增加， Rho-ROCK的激活，以及与SS-Arhgef 11同源相比FITC-白蛋白的摄取减少。 相反，在细胞系中敲低Arhgef 11导致RhoA活性降低， 在用TGFβ1刺激后，Rho-ROCK通路和与对照相比较少的应力纤维形成（促纤维化 细胞因子）。总之，动物和体外研究表明，RhoA通路的慢性激活， ARHGEF 11可能对肾损伤有显著影响。因此，我们的中心假设是， 在SS大鼠表现出的Arhgef 11中，导致Rho通路的慢性失调， 肾小管细胞的形态和功能，并最终导致肾损伤和肾功能下降。的 该提案的具体目的是：（1）研究Arhgef 11在肾损伤，肾血流动力学， 和血压，使用增强表达或敲除Arhgef 11（SS-Arhgef 11-/-）的动物模型; (2)使用原代细胞和遗传修饰的细胞研究近端小管细胞中Arhgef 11的参与， （3）研究特定的Arhgef 11遗传变异体/单倍型的作用（在大鼠和人类中） 负责改变表达/蛋白质功能和随后的Rho-ROCK激活。总而言之， 成功完成拟议的项目将导致更好地了解遗传学的作用， 高血压慢性肾脏病，肾脏疾病并发因素的影响，以及潜在的新治疗方法 目标的

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