Diabetic Albuminuria and VEGF and Nephrin

糖尿病蛋白尿以及 VEGF 和 Nephrin

基本信息

批准号：
7279861
负责人：
SHELDON CHEN
金额：
$ 7.33万
依托单位：
NORTHWESTERN UNIVERSITY AT CHICAGO
依托单位国家：
美国
项目类别：
财政年份：
2006
资助国家：
美国
起止时间：
2006-08-05 至 2008-07-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/7279861
关键词：
1-Phosphatidylinositol 3-Kinase Address Affect Albumins Albuminuria Animal Model Antibody Therapy Attention Biological Assay Blood Vessels Body Weight Collagen Type IV Congenital Nephrotic Syndrome Data Development Diabetes Mellitus Diabetic Nephropathy Diabetic mouse Environment Face Gene Expression Gene Proteins In Vitro Intercept Knock-out Knockout Mice Knowledge Laboratories Lead Letters Ligands Mediating Messenger RNA Mutate Nitric Oxide Numbers Pan Genus Pathway interactions Phosphotransferases Play Protein Isoforms Protein Kinase C Protein Tyrosine Kinase Proteins Proteinuria Receptor Protein-Tyrosine Kinases Receptor Signaling Renal function Role SU 5416 Signal Transduction Streptozocin Study Section System Technology Testing Tetracycline Tetracyclines Time Transgenic Mice Translations Tyrosine Vascular Endothelial Growth Factor A Vascular Endothelial Growth Factor Receptor Vascular Endothelial Growth Factor Receptor-1 Vascular Endothelial Growth Factor Receptor-2 Vascular Endothelial Growth Factor Receptor-3 Vascular Endothelial Growth Factors Week Work autocrine cell type db/db mouse diabetic expectation glomerular basement membrane glomerular filtration hemodynamics improved inhibitor/antagonist kidney cell kidney vascular structure membrane synthesis nephrin neutralizing antibody non-diabetic novel podocyte prevent protein degradation receptor research study type I and type II diabetes

项目摘要

DESCRIPTION (provided by applicant): Vascular endothelial growth factor (VEGF)-dependent albuminuria has been demonstrated in animal models of both type 1 and type 2 diabetes (de Vriese, JASN 2001 and Flyvbjerg, Diabetes 2002). Instead of targeting the VEGF ligand with a neutralizing antibody as in the cited studies above, we decided to target the VEGF signaling receptors with an inhibitor, SU5416, to see if this would replicate the benefits of anti-VEGF antibody therapy. Our Specific Aim 1 was to test if inhibition of VEGF receptor signaling ameliorates albuminuria and restores nephrin expression in diabetic db/db mice. When administered at 2 mg/kg of body weight twice-a-week for eight weeks, SU5416 almost completely prevented albuminuria, reversed glomerular basement membrane thickening, and partly restored nephrin expression toward the non-diabetic baseline. However, because SU5416 blocks all three VEGF receptor kinases and was given systemically, we could not pinpoint which receptor signaling in which renal cell type might have mediated the VEGF-dependent diabetic albuminuria. We hypothesize that the VEGFR-1 receptor in the podocyte was predominantly responsible for the manifestations of diabetic nephropathy that were improved by SU5416 treatment. Thus, Specific Aim 2 tests if deletion of VEGFR-1 specifically in the podocyte will ameliorate albuminuria, GBM thickening, and nephrin protein reduction in the streptozotocin (STZ)-induced diabetic mouse. Targeted deletion of podocyte VEGFR-1 will be accomplished with Cre/loxP technology and the tetracycline-regulatable gene expression system to create a conditional knockout mouse that will be induced with diabetes; this approach should avoid the developmental problems that a conventional allelic knockout might cause. Finally, we will examine the most novel finding from the db/db-SU5416 experiment in that diabetes- induced changes in nephrin expression can be partly corrected by a specific inhibitor of VEGF signaling. Specific Aim 3 will elucidate the mechanisms underlying the VEGF-modulated expression of nephrin by 1) defining the role of VEGF receptors in regulating nephrin expression in cultured podocytes, 2) identifying specific tyrosine residues on the VEGF receptor(s) that are activated by VEGF and the diabetic environment, 3) characterizing the downstream pathways that potentially mediate VEGF-stimulated changes in nephrin expression, including those involving the phosphatidylinositol 3-kinase and protein kinase C pathways, and 4) determining whether VEGF decreases nephrin translation efficiency or increases its protein degradation, as a possible mechanism for the reduced nephrin protein in the face of increased nephrin mRNA (Prelim. Data).

描述（由申请人提供）：血管内皮生长因子（VEGF）依赖性蛋白尿已在1型和2型糖尿病的动物模型中证明（de Vriese，Jasn 2001和Flyvbjerg，糖尿病，2002年）。我们决定使用抑制剂SU5416靶向VEGF信号受体，而不是用中和抗体靶向VEGF配体，以查看这是否会复制抗VEGF抗体疗法的益处。我们的特定目的1是测试VEGF受体信号传导的抑制是否可以改善蛋白尿症并恢复糖尿病DB/DB小鼠中的肾蛋白表达。当每周两次以2 mg/kg体重给药八周时，SU5416几乎完全阻止了蛋白尿，反向肾小球基底膜增厚，并部分恢复了肾蛋白表达，朝着非糖化基线。但是，由于SU5416阻断了所有三种VEGF受体激酶并被系统地给出，因此我们无法查明哪种受体信号传导，其中肾细胞类型可能介导了VEGF依赖性糖尿病蛋白尿。我们假设足细胞中的VEGFR-1受体主要负责SU5416治疗改善的糖尿病性肾病的表现。因此，如果在足细胞中特异性vegfr-1的缺失将改善链蛋白酶（STZ）诱导的糖尿病小鼠的肾蛋白蛋白质还原，则特定的目标2测试。 Podocyte VEGFR-1的有针对性删除将通过CRE/LOXP技术和四环素调节基因表达系统来实现，以创建一种条件敲除小鼠，该小鼠将由糖尿病引起。这种方法应避免常规等位基因敲除可能引起的发展问题。最后，我们将研究DB/DB-SU5416实验中最新的发现，即糖尿病诱导的肾蛋白表达的变化可以通过特定的VEGF信号传导的特定抑制剂来部分纠正。具体目标3将通过1）定义VEGF受体在调节培养的足细胞中调节肾素表达在调节肾蛋白表达中的作用的特定目标3，2）定义VEGF受体在调节培养的足细胞中的作用，2）识别在VEGF受体上识别VEGGF和糖尿病环境激活的特定酪氨酸残基，以使糖尿病的环境变化，3）供应效率化的效率变化。肾蛋白表达，包括涉及磷脂酰肌醇3-激酶和蛋白激酶C途径的表达，以及4）确定VEGF是降低肾素的翻译效率还是增加其蛋白质降解，作为增加肾蛋白降低肾蛋白的可能机制。