MOLECULAR MECHANISMS OF RENAL FIBROSIS

描述(摘自《研究人员摘要》)：间质纤维化 是大多数终末期肾病的最终共同途径。 成纤维细胞是导致这一纤维化过程的主要因素。 但人们对它们的来源以及它们在肾脏中是如何参与的知之甚少。 受伤。问题的一部分是用于鉴定的好试剂 正常组织中的成纤维细胞还不可用。在过去的几年里 几年来，这些调查人员试图开发新的探测器，以帮助更好地 确认这些细胞。为了促进成纤维细胞的研究，他们最近 克隆了一种名为成纤维细胞特异性蛋白-1(FSP1)的蛋白质 对小鼠组织中的成纤维细胞具有微妙的特异性。FSP1属于 钙调素-S100-肌钙蛋白C超家族细胞内钙结合 蛋白质。S100超级家族的成员在 微管动力学，细胞骨架-膜相互作用，细胞生长， 和差异化。FSP1不仅是成纤维细胞的标志物，而且 在形成间充质细胞表型方面具有指导作用 FSP1在肾小管上皮细胞中的过度表达表明 诱导表型转化为成纤维细胞，诱导FSP1表达 在肾小管上皮细胞中，细胞因子会产生同样的变化，而这 表型转换可被反义寡聚物阻断 FSP1。这种蛋白质在体内似乎也有类似的作用，就像小管一样。 被间质性肾炎困住的上皮细胞开始表达FSP1，而 在纤维化的早期阶段从肾单位解聚。AS 肾小管萎缩时，FSP1+细胞数量增加，提示 成纤维细胞可能通过上皮间充质过程在局部形成。 转换(EMT)。申请人打算进一步评估该EMT 转基因假说和以FSP1为探针的分子技术。 例如，已经建立了酵母单杂交系统来筛选 结合成纤维细胞特异性位点(FTS-1)的转录因子 在FSP1启动子中发现，赋予成纤维细胞特异性。A FSP1 基因敲除小鼠将探索FSP1在糖尿病的发展和命运中的作用 成纤维细胞，其他小鼠的肾小管上皮细胞将被标记为 可被Cre重组酶激活的休眠转基因(LacZ) 如果它后来在纤维形成过程中出现在成纤维细胞中，最后，它们 已经开发出一种使用胸苷激酶的分子自杀方法 转基因更昔洛韦选择性抗肾纤维化作用研究 杀死组织成纤维细胞。上游监管机构的识别 在转基因小鼠中转录和更好地理解FSP1是一种 试图发现引导人类进化的分子程序第一步 成纤维细胞间充质表型。这可能是理解如何 来控制他们在疾病期间的行为。

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.