TGF BETA EXPRESSION FOLLOWING ISCHEMIC ACUTE RENAL FAIL

急性肾衰竭是一种主要的临床并发症，与约50%的死亡率相关。 目前，除了支持性治疗和透析外，还没有针对这种疾病的既定疗法。 转化生长因子β（TGF-β）是一种多肽生长因子，被认为有助于肾纤维化。 然而，其细胞外基质促进特性可能在急性肾衰竭的情况下在肾脏中起重要的功能作用。 本研究旨在阐明转化生长因子-β（TGF-β）在急性肾缺血肾修复过程中的作用。 它假设TGF-β活性在肾缺血后损伤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。其中包括1）观察到TGF-β 1 mRNA和肽在大鼠缺血后再生的近端小管中表达。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用TGF-β的中和抗体显著减弱。第一组目标旨在鉴定和表征体内响应于肾损伤的TGF-β活性。 在具体目标1中，将鉴定、定位TGF-β信号传导受体，并测量其响应于肾损伤的活性。具体目标2将确定TGF-β 1肽对大鼠缺血性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-β 1基因的缺失是否会影响TGF-β 1-/-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，我们将确定缺血性损伤后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DNA酶I足迹法和凝胶位移分析鉴定TGF-β 1基因5'近端启动子区的潜在相关顺式作用元件，这些元件证明缺血性损伤后转录因子结合活性的改变。 这些实验将提供重要的数据有关的作用，高表达的生长因子在模型中的肾损伤，并提供新的见解可能的机制，肾脏修复缺血性损伤后。

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.