Mechanisms of Glomerular Scarring
肾小球疤痕形成的机制
基本信息
- 批准号:6776511
- 负责人:
- 金额:$ 29.35万
- 依托单位:
- 依托单位国家:美国
- 项目类别:
- 财政年份:2003
- 资助国家:美国
- 起止时间:2003-09-01 至 2007-06-30
- 项目状态:已结题
- 来源:
- 关键词:biomarkerconfocal scanning microscopyelectron microscopyfluorescence microscopygene expressiongene mutationgene targetinggenetic disordergenetically modified animalsglomerular filtrationglomerulosclerosisgreen fluorescent proteinsimmunocytochemistryin situ hybridizationlaboratory mousepathologic processphenotypepolymerase chain reactionprotein transportregulatory generenal glomerulustranscription factorwestern blottingsyeast two hybrid system
项目摘要
DESCRIPTION (provided by applicant): Glomerular scarring is a hallmark of progressive kidney disease. Identifying molecular mechanisms of rare, familial kidney diseases has provided insights into the pathogenesis of sporadic nephropathy. Mutations in genes encoding podocyte proteins, which comprise the filtration barrier or regulate podocyte phenotype, have been discovered by genetic analyses of families with glomerulosclerosis, suggesting a podocyte phenotype "switch" is a critical mechanism of glomerular scarring. We postulated that regulatory pathways transmit information from filtration barrier to nucleus to regulate podocyte differentiation state in response to environmental signals. WT1, a zinc finger transcription factor, critical for appropriate podocyte differentiation, expressed in mature podocytes and is mutated in familial glomerulosclerosis. WT1 expression is diminished in some human and experimental glomerular diseases, but podocyte expression of WT1 target genes, podocalyxin and nephrin, is diminished even when WT1 levels are unchanged. Using a two-hybrid assay to identify regulators of WT1 activity in a mouse kidney library, we identified a novel protein, WT1 interacting protein (WTIP). WTIP maps within a locus for familial focal sclerosis (FSGS1) on human chromosome 19q13.1 and is part of a family of zyxin-like molecules, which contain 3 LIM domains and shuttle between cytoplasm and nucleus. Our preliminary data demonstrated that WTIP is expressed in podocytes in culture and in vivo. Ectopically expressed WTIP co-localized with CD2-associated protein (CD2AP) in podocyte actin spots, sites of dynamic actin filament reorganization. Full-length WTIP, in the presence of the nuclear export inhibitor leptomycin, was retained in the nucleus, co-localized and coprecipitated with WT1, and inhibited WTl-dependent transcriptional activation of the amphiregulin promoter. Based on these data, we hypothesize the following: (1) In normal glomeruli WTIP is part of a multiprotein complex in podocyte foot process and may link the CD2AP/nephrin/podocin complex to adherens junction proteins by regulating dynamic actin assembly. (2) After injury, WTIP translocates into the nucleus, where it represses WTl-dependent gene expression to dysregulate podocyte phenotype. (3) Loss of WTIP from its cytosolic location also promotes redistribution of slit diaphragm proteins and actin rearrangement characteristic of foot process effacement. In vitro and in vivo experiments will test the validity of our model.
描述(申请人提供):肾小球疤痕形成是进展性肾脏疾病的标志。识别罕见的家族性肾脏疾病的分子机制为研究散发性肾病的发病机制提供了新的思路。通过对肾小球硬化家系的遗传分析,发现了足细胞蛋白编码基因的突变,这些基因构成了滤过屏障或调节足细胞表型,提示足细胞表型转换是肾小球瘢痕形成的关键机制。我们推测,调节通路将信息从滤过屏障传递到细胞核,以调节足细胞的分化状态,以响应环境信号。WT1是一种锌指转录因子,对足细胞的适当分化至关重要,在成熟的足细胞中表达,在家族性肾小球硬化中突变。WT1在某些人类和实验性肾小球疾病中的表达减少,但WT1靶基因的足细胞表达即使在WT1水平不变的情况下也会减少。使用双杂交方法在小鼠肾脏文库中鉴定WT1活性的调节因子,我们鉴定了一种新的蛋白,WT1相互作用蛋白(WTIP)。WTIP定位于人类染色体19q13.1上的家族性局灶性硬化症(FSGS1)基因座,是Zyxin样分子家族的一部分,该家族含有3个LIM结构域,穿梭于细胞质和细胞核之间。我们的初步数据表明,WTIP在培养和体内足细胞中都有表达。异位表达的WTIP与CD2相关蛋白(CD2AP)共定位于足细胞肌动蛋白斑点,即肌动蛋白细丝动态重组的部位。全长WTIP在核出口抑制剂利托霉素存在的情况下,保留在细胞核内,与WT1共定位和共沉淀,并抑制WT1依赖的双调节蛋白启动子的转录激活。基于这些数据,我们假设:(1)在正常肾小球中,WTIP是足细胞足突多蛋白复合体的一部分,可能通过调节动态肌动蛋白组装将CD2AP/newitin/podocin复合体与黏附连接蛋白联系起来。(2)损伤后WTIP移位到细胞核,抑制WT1依赖的基因表达,从而失调足细胞表型。(3)WTIP胞浆位置的丢失也促进了裂隙隔蛋白的重新分布和足突消失的肌动蛋白重排特征。体外和体内实验将检验我们模型的有效性。
项目成果
期刊论文数量(0)
专著数量(0)
科研奖励数量(0)
会议论文数量(0)
专利数量(0)
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JOHN R. SEDOR其他文献
JOHN R. SEDOR的其他文献
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{{ truncateString('JOHN R. SEDOR', 18)}}的其他基金
New Paradigms in Vascular Biology: Renal Implications
血管生物学的新范式:对肾脏的影响
- 批准号:
6854072 - 财政年份:2005
- 资助金额:
$ 29.35万 - 项目类别:
REGULATION OF MESANGIAL CELL ACTIVATION BY GLOMERULAR MICROENVIRONMENT
肾小球微环境对系膜细胞活化的调节
- 批准号:
6651769 - 财政年份:2002
- 资助金额:
$ 29.35万 - 项目类别:
REGULATION OF MESANGIAL CELL ACTIVATION BY GLOMERULAR MICROENVIRONMENT
肾小球微环境对系膜细胞活化的调节
- 批准号:
6499591 - 财政年份:2001
- 资助金额:
$ 29.35万 - 项目类别:
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