MOLECULAR MECHANISMS OF RENAL FIBROSIS

描述（改编自研究者摘要）：间质纤维化 是大多数终末期肾病的最终共同途径。 成纤维细胞是负责这一纤维化过程的主要代理人 但关于它们的起源或它们在肾功能衰竭期间是如何参与的， 损伤 问题的一部分是， 正常组织中的成纤维细胞尚未获得。 在过去 几年来，这些研究人员试图开发新的探针，以帮助更好地 识别这些细胞。 为了促进成纤维细胞的研究，他们最近 克隆了一种称为成纤维细胞特异性蛋白1（FSP 1）的蛋白质， 对鼠组织中的成纤维细胞具有特异性。 FSP 1属于 细胞内钙结合的钙调素-S100-肌钙蛋白C超家族 proteins. S100超家族的成员在以下方面具有独立的作用： 微管动力学，细胞间隙-膜相互作用，细胞生长， 和差异化。 FSP 1不仅是成纤维细胞的标志物， 在形成它们的间充质表型方面起着指导作用， 肾小管上皮细胞中FSP 1的过度表达 诱导成纤维细胞的表型转化，诱导FSP 1表达 细胞因子在肾小管上皮细胞中产生同样的变化， 表型转化可被反义寡聚体阻断， FSP1. 这种蛋白质在体内似乎也有类似的作用， 被间质性肾炎所困的上皮开始表达FSP 1， 在纤维化的早期阶段从肾单位解聚。 作为 肾小管萎缩，FSP 1+细胞数量增加，表明 成纤维细胞可能通过上皮-间充质细胞分化过程局部产生， 转换（EMT）。 申请人打算进一步评估EMT 以FSP 1为探针，通过转基因和分子技术， 例如，已经建立了酵母单杂交系统来筛选 与成纤维细胞特异性位点（FTS-1）结合的转录因子， 在FSP 1启动子中发现，FSP 1启动子赋予成纤维细胞特异性。 A FSP1 敲除小鼠将探索FSP 1在发育和命运中的作用。 成纤维细胞，其他小鼠将其肾小管上皮细胞标记有 休眠转基因（LacZ），可以用Cre重组酶激活， 如果它后来出现在纤维形成过程中的成纤维细胞中，最后， 开发了一种利用胸苷激酶的分子自杀方法 转基因与更昔洛韦，以减轻肾纤维化， 杀死组织成纤维细胞。 上游调节因子的识别 转录和更好地了解FSP 1基因修饰小鼠是一个很好的方法。 第一步，试图揭示分子程序，指导 成纤维细胞的间充质表型。 这可能是理解 来控制他们的行为

DESCRIPTION (Adapted from Investigator's Abstract): Interstitial fibrosis is the final common pathway to most forms of end-stage renal disease. Fibroblasts are the principal agent responsible for this fibrotic process but little is known about their origin or how they are engaged during renal injury. Part of the problem has been that good reagents for identifying fibroblasts in normal tissues have not been not available. Over the last few years these investigators tried to develop new probes to help better identify these cells. To facilitate the study of fibroblasts, they recently cloned a protein called fibroblast-specific protein-1 (FSP1) which is exquisitely specific for fibroblasts in murine tissues. FSP1 belongs to the calmodulin-S100-troponin C superfamily of intracellular calcium-binging proteins. Members of the S100 superfamily have a discrete role in microtubule dynamics, cytoskeletal-membrane interactions, cellular growth, and differentiation. FSP1 is not only a marker of fibroblasts, but also plays an instructive role in shaping their mesenchymal phenotype as indicated by the fact that overexpression of FSP1 in tubular epithelium induces a phenotypic conversion to fibroblasts, induction of FSP1 expression in tubular epithelium by cytokines produces the same change, and this phenotypic conversion can be blocked by antisense oligomers to mRNA encoding FSP1. This protein also appears to have a similar role in vivo, as tubular epithelium trapped by interstitial nephritis begin expressing FSP1 while the disaggregate from the nephron during the early stages of fibrosis. As tubular atrophy sets in, the number of FSP1+ cells increase, suggesting that fibroblasts might arise locally through a process of epithelial-mesenchymal transformation (EMT). The applicant's intend to further evaluate this EMT hypothesis with transgenic and molecular technology using FSP1 as a probe. For example, a yeast one-hybrid system has been set up to screen for transcription factors that bind to a fibroblast-specific site (FTS-1) that was found in the FSP1 promoter that confers fibroblast specificity. A FSP1 knockout mouse will explore the role of FSP1 in the development and fate of fibroblasts, other mice will have their tubular epithelium marked with a dormant transgene (LacZ) that can be activated with Cre-recombinase to see if it later appears in fibroblasts during fibrogenesis, and finally, they have developed a molecular suicide approach using thymidine kinase transgenes with gancyclovir to attenuate renal fibrosis by selectively killing tissue fibroblasts. Identification of upstream regulators of transcription and a better understanding of FSP1 in gene-modified mice is a first step in trying to uncover the molecular program that guides the mesenchymal phenotype of fibroblasts. It may be a key to understanding how to control their behavior during disease.