KIM-1, microparticles and diabetic tubular injury

KIM-1、微粒和糖尿病肾小管损伤

• 批准号: 8432030
• 负责人: Xueying Zhao
• 金额: $ 13.65万
• 依托单位: MOREHOUSE SCHOOL OF MEDICINE
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-03-01 至 2015-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8432030
• 关键词: Accounting; Address; Albumins; Albuminuria; Animal Model; Apoptosis; Apoptotic; Atrophic; BCL2 gene; Biological Markers; Cell Culture Techniques; Cell Survival; Cell membrane; Cells; Coculture Techniques; Data; Diabetes Mellitus; Diabetic Nephropathy; Disease Management; Disease Progression; Elements; End stage renal failure; Epithelial; Epithelial Cells; Figs - dietary; Functional disorder; Glucose; Goals; Human; In Vitro; Injury; Ischemia; Kidney; Kidney Diseases; Light; Mediator of activation protein; Modeling; Molecular; Mus; Pathogenesis; Pathway interactions; Pattern; Phagocytosis; Pharmaceutical Preparations; Pilot Projects; Proteins; Proteinuria; Rattus; Research; Resistance; Rodent; Role; Series; Signal Transduction; Stimulus; Stress; Testing; Tight Junctions; Tubular formation; Up-Regulation; Urine; Vesicle; base; caspase-3; cell injury; diabetic; diabetic rat; gain of function; in vivo; insight; monolayer; novel therapeutics; oxidized low density lipoprotein; prevent; rat KIM-1 protein; response; scavenger receptor; submicron; uptake; urinary

DESCRIPTION (provided by applicant): Diabetic nephropathy is now the most prevalent cause of end stage renal disease, accounting for 40-50% 1, and apoptosis has been shown to be an important mechanism for tubular atrophy, a sensitive predictor of disease progression. As the submicron vesicles shed from plasma membranes, microparticles (MPs) are found in the urine of healthy humans and rodents and their contents and amounts are altered following cell activation and apoptosis. The overall goal of the proposed studies is to uncover the mechanisms leading to renal secretion of MPs and their role in tubular injury in diabetes. Kidney injury molecule-1 (KIM-1) is a urinary biomarker for renal proximal tubular damage and has been recently identified as a scavenger receptor involved in epithelial phagocytosis. We found that tubular expression of KIM-1 was dramatically increased, in association with proteinuria and kidney injury, in Zucker diabetic fatty rats. In vitro studies using primary cultures of rat and mouse tubular cells revealed that albumin increased expression and vesicular accumulation of KIM-1 as well as its secretion via MP shedding. Moreover, this increase in KIM-1 expression was associated with an elevation of caspase-3 activity. Interestingly, knockdown of KIM-1 confers resistance to epithelial apoptosis as reflected by an up-regulation of bcl-2 and suppression of caspase-3 activation. We conducted additional pilot study indicating that tubular epithelial cells were capable of uptaking MPs and that the internalization of MPs containing KIM-1 (KIM-MPs) disrupted normal tight junction in tubular epithelial monolayer. Therefore, those preliminary results prompted our central hypothesis stating that "KIM-1/KIM- MPs contribute to tubular dysfunction by promoting cell injury and apoptosis". Specifically, we will address the following aims: Aim I. To test the hypothesis that tubular expression and secretion of KIM-1 are increased in response to albumin overload. Systematic analyses will be conducted to delineate expression, localization and secretion of KIM-1 in tubular epithelial cells in response to albumin overload and other apoptotic stimuli in both in vivo animal model and in vitro cell culture model. Aim II. To test the hypothesis that KIM-1/KIM-MPs contribute to tubular cell injury and apoptosis. The effects of KIM-1/KIM-MPs on tubular cell injury and apoptosis in response to albumin and other apoptotic stimuli will be determined by 1) examining the effects of loss- and gain-of-function of KIM-1 on tubular cell injury and apoptosis, 2) delineating the apoptotic pathways by which KIM-1 contributes to tubular cell apoptosis upon apoptotic stimulation, 3) determining the effects of KIM-MPs on the target cells by treating normal tubular epithelial cell monolayer with KIM-1 positive or KIM-1 negative microparticles. Together, the series of studies outlined in Aims I and II will enable us to provide new insights into the functional role of KIM-1/KIM-MPs in tubular injury and dysfunction associated with diabetic kidney disease. Our studies will also shed light on KIM-1/KIM-MPs as attractive targets for kidney disease management.

描述（由申请人提供）：糖尿病性肾病现在是最普遍的末期肾脏疾病的原因，占40-50％1，凋亡已被证明是管状萎缩的重要机制，是疾病进展的敏感预测指标。由于从质膜中脱落的亚微米囊泡，在健康的人类和啮齿动物的尿液中发现了微粒（MPS），其含量和含量在细胞激活和凋亡后会改变。拟议的研究的总体目标是发现导致MPS肾脏分泌及其在糖尿病中肾小管损伤中的作用的机制。肾损伤分子1（KIM-1）是肾近端管状损伤的尿生物标志物，最近已被鉴定为参与上皮吞噬作用的寻宝受体。我们发现，在扎克糖尿病脂肪大鼠中，KIM-1的管状表达与蛋白尿和肾脏损伤有关。使用大鼠和小鼠管细胞的一级培养物的体外研究表明，白蛋白增加了KIM-1的表达和水泡积累，以及通过MP脱落的分泌。此外，KIM-1表达的增加与caspase-3活性的升高有关。有趣的是，KIM-1的敲低赋予对上皮细胞凋亡的抗性，这反映了Bcl-2的上调和抑制caspase-3激活。我们进行了进一步的试点研究，表明管状上皮细胞能够吸收MPS，并且含有KIM-1（KIM-MPS）的MP的内在化破坏了管状上皮单层中的正常紧密连接。因此，这些初步结果促使我们的中心假设指出“ KIM-1/KIM-MPS通过促进细胞损伤和凋亡促进了管状功能障碍”。具体而言，我们将解决以下目的：目标I，以检验以下假设：KIM-1的管状表达和分泌因白蛋白的过载而增加。将进行系统的分析，以描绘在体内动物模型和体外细胞培养模型中，响应白蛋白过载和其他凋亡刺激的响应在管状上皮细胞中的表达，定位和分泌。目标II。为了测试KIM-1/KIM-MP有助于管状细胞损伤和凋亡的假设。 KIM-1/KIM-MP对响应白蛋白和其他凋亡刺激对肾小管细胞损伤和凋亡的影响将通过1）检查KIM-1检查KIM-1对肾小管细胞损伤和凋亡的功能的影响，2）2）通过该刺激促进apoptiss的影响，以确定Kim-1的刺激性刺激，以确定3个刺激性的刺激性，以确定apotic ap的影响，以确定apoptiss ap的影响KIM-MP通过使用KIM-1阳性或KIM-1负微粒处理正常的管状上皮细胞单层。总之，AIM I和II中概述的一系列研究将使我们能够对KIM-1/KIM-MP在管状损伤和与糖尿病肾脏疾病相关的功能障碍中的功能作用提供新的见解。我们的研究还将阐明KIM-1/KIM-MP作为肾脏疾病管理的有吸引力的目标。