A Mouse Model for Glomerulosclerosis and Early Onset Renal Failure

描述（由申请人提供）：肾小球硬化是进展性肾衰竭的关键和共同特征，是美国发病率和死亡率的主要原因。尽管已知几种遗传和环境损害可导致原发性肾小球硬化，但它们启动肾小球硬化过程的细胞机制仍在很大程度上未知。为了阐明这些机制，我们产生了一种新的小鼠品系，其Wt1基因携带错义突变（R394W），该基因编码锌指转录因子，并在肾小球足细胞中表达。在人类中，H/nR394W突变导致弥漫性肾小球系膜硬化和早发性肾衰竭，Wt1+/R3g4w杂合小鼠模拟这种表型，早在两个月大时就出现蛋白尿和肾小球硬化。我们推测，由于Wt1是一种转录因子，其突变导致足细胞表达的关键基因失调，最终导致肾小球硬化。我们将通过使用Affymetrix微阵列芯片比较高危突变型肾脏和野生型肾脏的基因表达谱来识别这些失调基因。这项工作将使我们能够识别在肾小球硬化中起关键作用但尚未被认识的基因，从而扩大对这种疾病过程的理解。为了确定基因表达失调的功能意义，我们将使用体外（永生化足细胞细胞系）和体内（超声介导的基因转移）两种方法来调节基因表达/通路功能。我们将评估这种调节在细胞表型方面的影响，以及在突变小鼠中延迟疾病发生/进展的能力。我们已经确定疾病的发病是由Wt1突变携带的遗传背景显著调节的。我们假设这是由于不同小鼠品系的修饰基因不同，我们将定位这个位点（位点）。在一般人群中，引发肾小球硬化和肾衰竭过程的初始细胞变化尚不清楚。H/T7R394W小鼠携带一种已知会导致人类肾衰竭的突变；它是研究肾小球硬化病理生物学的一种极好的、具有生物学相关性的动物模型。它将使我们能够识别在疾病过程的早期阶段发生的遗传和细胞变化。它也为开发和测试新的干预和治疗策略提供了一个很好的系统。

DESCRIPTION (provided by applicant): Glomerulosclerosis is a key and common feature of progressive renal failure which is a major cause of morbidity and mortality in the U.S. Although several genetic and environmental insults are known to cause primary glomerulosclerosis, the cellular mechanism(s) by which they initiate the process of glomerulosclerosis is still largely unknown. To elucidate these mechanisms, we generated a novel mouse strain carrying a missense mutation (R394W) in the Wt1 gene which encodes a zinc finger transcription factor and is expressed in the glomerular podocyte. In humans the H/nR394W mutation results in diffuse mesangial sclerosis and early onset renal failure, and Wt1+/R3g4w heterozygous mice mimic this phenotype, developing proteinuria and glomerulosclerosis as early as two months of age. We hypothesize that because Wt1 is a transcription factor, its mutation results in dysregulation of key podocyte-expressed genes which ultimately results in glomerulosclerosis. We will identify these dysregulated genes by comparing the gene expression profile of at-risk mutant kidneys and wildtype kidneys using Affymetrix microarray chips. This work will enable us to identify genes whose altered expression plays a critical, but not yet recognized, role in glomerulosclerosis, thereby expanding the understanding of this disease process. To determine the functional significance of dysregulated gene expression, we will use both in vitro (immortalized podocyte cell lines) and in vivo (ultrasound-mediated gene transfer) approaches to modulate gene expression/pathway function. We will assess the effect of this modulation in terms of cellular phenotype and also the ability to delay disease onset/progression in mutant mice. We have determined that disease onset is dramatically modulated by genetic background on which the Wt1 mutation is carried. We hypothesize that this is due to a modifying gene(s) that differs among mouse strains, and we will localize this locus (loci). The initial cellular changes that initiate the process of glomerulosclerosis and kidney failure in the general population are not well understood. The H/T7R394W mouse carries a mutation known to cause renal failure in humans; it is an excellent and biologically relevant animal model for studying the pathobiology of glomerulosclerosis. It will enable us to identify genetic and cellular changes that occur at the earliest stages of the disease process. It also provides an excellent system for developing and testing new intervention and therapeutic strategies.