TGF BETA EXPRESSION FOLLOWING ISCHEMIC ACUTE RENAL FAIL

急性肾功能衰竭是一种主要的临床并发症，死亡率约为50%。目前，除了支持性护理和透析外，还没有针对这种疾病的既定治疗方法。转化生长因子-β是一种多肽生长因子，被认为与肾脏纤维化有关。然而，其促进细胞外基质的特性可能在急性肾功能衰竭的肾脏中发挥重要的功能作用。本研究旨在阐明转化生长因子-β在肾修复急性肾缺血中的作用。推测转化生长因子-β活性在肾缺血损伤的结构和功能恢复中起重要作用。最近的几项研究塑造了目前的提议。其中包括：1)观察到大鼠缺血后再生的近端小管有转化生长因子-β1基因及其多肽的表达。2)。观察到与组织重塑相关的细胞外基质(ECM)基因以与转化生长因子-β活性一致的方式表达。3)观察到这些ECM基因产物在缺血后被抗转化生长因子-β中和抗体显著减弱。第一组目标旨在确定和表征体内转化生长因子-β活性对肾脏损伤的反应。在特定的目标1中，将识别和定位转化生长因子-β信号受体，并测量其活性以响应肾脏损伤。具体目标2将确定转化生长因子-β1肽在大鼠肾脏缺血损伤后修复中的潜在有益作用。在特定的目标3中，我们将确定转化生长因子-β1基因的缺失是否影响转化生长因子-β1-/-小鼠的缺血后修复过程。在特定的目标2和3中，我们将通过测量肾功能、分析肾脏形态和测量与组织修复相关的基因表达来分析修复。第二组目标旨在了解肾脏对损伤的反应机制。在特定的第四个目标中，我们将确定是否通过RNA转录机制增强了缺血损伤后的转化生长因子-β活性。在特定的目标5中，我们将通过DNase I足迹和凝胶位移分析来鉴定转化生长因子-β1基因5‘端启动子区域潜在的相关顺式作用元件，这些元件显示缺血损伤后转录因子结合活性的改变。这些实验将提供有关高表达的生长因子在肾脏损伤模型中的作用的重要数据，并为肾脏在缺血损伤后自我修复的可能机制提供新的见解。

Acute renal failure is a major clinical complication associated with approximately 50 percent mortality. Currently there are no established therapies for this disorder beyond supportive care and dialysis. Transforming growth factor beta (TGF-beta) is a polypeptide growth factor thought to contribute to renal fibrosis. However, its extracellular matrix promoting properties may serve an important functional role in the kidney in the setting of acute renal failure. This proposal is directed toward elucidating the influence of transforming growth factor-beta (TGF-beta) plays during renal repair acute renal ischemia. It hypothesized that TGF-beta activity plays an important role in the structural and functional recovery of the kidney post-ischemic injury. Several recent studies have shaped the current proposal. Among them is 1) the observation that TGF-beta1 mRNA and peptide are expressed in regenerating proximal tubules post-ischemia in the rat. 2). The observation that extracellullar matrix (ECM) genes associated with tissue remodeling are expressed in a manner consistent with TGF-beta activity. 3) The observation that the expression of these ECM gene products are significantly attenuated with a neutralizing antibody to TGF-beta post-ischemia. The first set of goals are aimed at identifying and characterizing TGF-beta activity in vivo in response to renal injury. In specific aim number 1, TGF-beta signaling receptors will be identified, localized and their activity measured in response to renal injury. Specific aim number 2 will determine the potential beneficial effects of TGF-beta1 peptide on renal repair post-ischemic injury in rats. In specific aim number 3, we will determine if the loss of the TGF-beta1 gene affects the post-ischemic repair process in TGF-beta1 -/- mice. In specific aims number 2 and number 3 we will analyze repair by measuring renal function, analyzing renal morphology and measuring the expression of genes associated with tissue repair. A second set of goals is aimed at understanding the mechanism of the renal response to injury. In specific aim number 4 we will determine if TGF-beta activity post-ischemic injury is enhanced via RNA transcriptional mechanisms. In specific aim number 5, we will identify potentially relevant cis-acting elements of the 5' proximal promoter region of the TGF-beta1 gene that demonstrate altered transcriptional factor binding activity post-ischemic injury by DNAse I footprinting and gel-shift analysis. These experiments will provide important data concerning the role of a highly expressed growth factor in a model of renal injury and provide new insight into the possible mechanism by which the kidney repairs itself following ischemic injury.