TGF BETA EXPRESSION FOLLOWING ISCHEMIC ACUTE RENAL FAIL

急性肾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之外，尚无针对这种疾病的既定治疗方法。转化生长因子（tgf - β）是一种多肽生长因子，被认为与肾纤维化有关。然而，它的细胞外基质促进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。该建议旨在阐明转化生长因子- β (tgf - β)在肾修复急性肾缺血中的作用。假设tgf - β活性在肾缺血损伤后的结构和功能恢复中起重要作用。最近的几项研究形成了目前的建议。其中1)观察到大鼠缺血后近端小管再生中tgf - β 1 mRNA和肽的表达。2)。观察到与组织重塑相关的细胞外基质（ECM）基因以与tgf - β活性一致的方式表达。3)观察到这些ECM基因产物的表达在缺血后被tgf - β中和抗体显著减弱。第一组目标旨在识别和表征体内对肾损伤的反应中的tgf - β活性。在具体目标1中，tgf - β信号受体将被识别、定位，并在肾损伤反应中测量其活性。特异性目的2将确定tgf - β 1肽对大鼠缺血损伤后肾修复的潜在有益作用。在具体目标3中，我们将确定TGF-beta1基因的缺失是否会影响TGF-beta1 -/-小鼠的缺血后修复过程。在具体目标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。在具体目标4中，我们将确定缺血损伤后tgf - β活性是否通过RNA转录机制增强。在具体目标5中，我们将通过DNAse I足迹和凝胶转移分析确定tgf - β 1基因5'近端启动子区域潜在的相关顺式作用元件，这些元件在缺血性损伤后显示出转录因子结合活性的改变。这些实验将提供关于高表达生长因子在肾损伤模型中的作用的重要数据，并为肾在缺血性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.