Novel mechanisms of diabetic nephropathy

糖尿病肾病的新机制

基本信息

批准号：
7617188
负责人：
BALAKUNTALAM S KASINATH
金额：
$ 26.4万
依托单位：
UNIVERSITY OF TEXAS HLTH SCIENCE CENTER
依托单位国家：
美国
项目类别：
财政年份：
2007
资助国家：
美国
起止时间：
2007-07-01 至 2012-04-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/7617188
关键词：
1-Phosphatidylinositol 3-Kinase 5&apos -AMP-activated protein kinase AMP-activated protein kinase kinase Accounting Acetyl-CoA Carboxylase Address Affect Albuminuria Amides Antibodies Binding Biological Assay Cells Chemicals Collagen Type IV Complex Constitution Consumption Creatinine clearance measurement Cues Data Diabetes Mellitus Diabetic Nephropathy Dimerization Dissociation Dominant-Negative Mutation Dose Epithelial Epithelial Cells Eukaryotic Initiation Factor-4E Event Evolution Extracellular Matrix Fibronectins Figs - dietary Gene Expression Genetic Transcription Genetic Translation Glomerular Mesangial Cell Glucose Hyperglycemia Hypertrophy Immunoblotting Immunohistochemistry In Vitro Incubated Injury Insulin-Dependent Diabetes Mellitus Kidney Knockout Mice Laminin Mannitol Mediating Mediator of activation protein Messenger RNA Metformin Modeling Mus Non-Insulin-Dependent Diabetes Mellitus Oryctolagus cuniculus Pathologic Processes Pathology Pathway interactions Peptides Phase Phospho-Specific Antibodies Phosphorylation Phosphotransferases Play Principal Investigator Process Protein Biosynthesis Protein Kinase C Proteins RNA RNA Cap-Binding Proteins Rattus Recruitment Activity Regulation Research Personnel Reticulocytes Ribosomes Rodent Rodent Model Role Signal Pathway Signal Transduction Sirolimus Site Specific qualifier value Staging Streptozocin Sucrose System TSC1 gene Testing Time Translations Tubular formation base blood glucose regulation cell growth db/db mouse diabetic rat genetic manipulation human FRAP1 protein in vitro Assay in vivo inhibitor/antagonist kidney cell kidney cortex kinase inhibitor mTOR Inhibitor morphometry novel programs research study sensor translation assay type I and type II diabetes type I diabetic upstream kinase urinary

项目摘要

DESCRIPTION (provided by applicant): Energy status of cells is altered by diabetes; its role in diabetes-induced kidney injury is not well studied. Diabetic nephropathy is characterized by renal hypertrophy and extracellular matrix accumulation. mRNA translation, an energy consuming process, is the rate-limiting step in protein synthesis and is a site of regulation even when gene expression is controlled by transcription. However, the role of energy sensors in regulation of mRNA translation underlying diabetes-induced renal hypertrophy and matrix synthesis has not been addressed. We wish to examine the role of an important energy sensor, AMP-activated protein kinase (AMPK), in renal hypertrophy and matrix accumulation. The rationale for these studies is based on the following preliminary data. Phosphorylation of AMPK and its activity are reduced in association with high glucose-induced increase in protein synthesis and hypertrophy, and increase in matrix protein synthesis in renal cells, as well as, in renal cortex and glomeruli of rodents with type 1 or type 2 diabetes at the stage of renal hypertrophy. Administration of metformin and AICAR restores reduced AMPK phosphorylation and inhibits renal hypertrophy seen in the type 1 diabetic rat. However, the role of AMPK in progressive renal injury in type 1 or type 2 diabetes is not known. We wish to test the hypothesis that AMPK activity regulates renal hypertrophy and matrix accumulation in type 1 and type 2 diabetes. Our Specific Aims are: Specific aim 1. In vitro studies. (A) To explore mediators and signaling pathways involved in high glucose regulation of AMPK phosphorylation. Glomerular epithelial, mesangial and proximal tubular epithelial cells in culture will be studied under conditions of hyperglycemia that induce cell hypertrophy, and stimulate mRNA translation and synthesis of matrix proteins. We will investigate if altered AMP-ATP content, activity of LKB-1, an upstream kinase for AMPK, PI 3-kinase-Akt axis, and PKC-TGF-3 axis serve as upstream cues to regulate changes in AMPK phosphorylation and activity. (B) To investigate AMPK regulation of initiation and elongation phases of mRNA translation. The downstream effects of AMPK in regulation of critical events initiation and elongation phases of mRNA translation will be studied; signaling pathways mediating AMPK effect will be elucidated. (C) To explore the role of AMPK in high glucose induced matrix synthesis by renal cells in the context of augmented mRNA translation of matrix proteins. Polyribosomal assays and in vitro translation assays will be employed to define the role of AMPK. Specific aim 2. In vivo studies. To explore role of AMPK in renal pathology in type 1 or type 2 diabetes. Regulation of AMPK phosphorylation by aforementioned upstream factors and its activity and regulation of downstream effectors will be studied in the early stage (4 -14 days) of renal hypertrophy and established stage (3 months) of matrix accumulation and correlated with functional changes in albuminuria and changes in GFR. The ability of AICAR and metformin to inhibit both the anatomical and functional changes induced by diabetes in rodent models of type 1 and type 2 diabetes will be explored. AMPK alphal knock out mice will be studied for evolution of renal abnormalities in type 1 and type 2 diabetes. These studies may identify AMPK as a novel mediator of injury and a treatment target in diabetic nephropathy.

描述（由申请人提供）：细胞的能量状态被糖尿病改变；它在糖尿病引起的肾脏损伤中的作用尚未得到很好的研究。糖尿病性肾病的特征是肾脏肥大和细胞外基质积累。 mRNA翻译是一种能量消耗过程，是蛋白质合成的速率限制步骤，即使在基因表达受转录控制的情况下，也是调节的位置。然而，尚未解决能量传感器在调节糖尿病诱导的肾脏肥大和基质合成基础mRNA翻译中的作用。我们希望研究重要的能量传感器，AMP激活的蛋白激酶（AMPK）在肾脏肥大和基质积累中的作用。这些研究的理由基于以下初步数据。与高葡萄糖诱导的蛋白质合成和肥大的增加以及肾细胞中基质蛋白合成的增加以及肾皮质和啮齿动物的肾小球在具有1或类型2型糖尿病的肾素皮质和肾小球中，AMPK及其活性的磷酸化及其活性降低。在肾脏肥大的阶段。二甲双胍和AICAR的给药可恢复降低的AMPK磷酸化并抑制1型糖尿病大鼠中看到的肾肥大。但是，AMPK在1型或2型糖尿病中进行性肾脏损伤中的作用尚不清楚。我们希望测试AMPK活性调节肾脏肥大和基质在1型和2型糖尿病中的积累的假设。我们的具体目的是：特定目标1。体外研究。（a）探索参与AMPK磷酸化高葡萄糖调节的介体和信号通路。在诱导细胞肥大的高血糖条件下，将研究培养中肾小球上皮，肾小球上皮细胞，并刺激基质蛋白的mRNA翻译和合成。我们将研究AMP-ATP含量的改变，LKB-1的活性，AMPK上游激酶，PI 3-激酶-AKT轴和PKC-TGF-3轴作为上游提示，以调节AMPK磷酸化和活性的变化。（b）研究mRNA翻译的启动和伸长阶段的AMPK调节。将研究AMPK在调节关键事件启动和mRNA翻译伸长阶段的下游效应。介导AMPK效应的信号通路将被阐明。（c）在基质蛋白的增强mRNA翻译的背景下，探索AMPK在高葡萄糖诱导的基质合成中的作用。多核糖体测定和体外翻译测定将用于定义AMPK的作用。特定目标2。体内研究。探索AMPK在1型或2型糖尿病中肾脏病理学中的作用。通过上述上游因素来调节AMPK磷酸化及其在肾脏肥大的早期（4 -14天）的活动和下游效应子的调节，并与矩阵积累的既定阶段（3个月）进行研究，并与白蛋白尿症和白蛋白尿素和白蛋白尿素和功能变化相关GFR的变化。 AICAR和二甲双胍能够抑制糖尿病在1型和2型糖尿病啮齿动物模型中诱导的解剖和功能变化的能力。将研究AMPKα敲除小鼠，以用于1型和2型糖尿病中肾异常的进化。这些研究可能将AMPK鉴定为糖尿病性肾病中损伤的新介质和治疗靶标。