Pathology of Renal Matrix Metabolism

间质纤维化和肾小管萎缩是所有形式进行性肾纤维化的特征。这 实验室在过去的十年里一直专注于特定的基质金属蛋白酶(MMP2和MMP2)的作用 MT1-MMP1)参与这一过程。基质金属蛋白酶-2，结合MT1-基质金属蛋白酶，足以诱导细胞转化。 极化上皮细胞向成纤维细胞表型转化--一种上皮间质转化过程 (EMT)。定量地，EMT结合间质成纤维细胞的激活和扩张 是肾小管萎缩和进行性肾纤维化的主要因素。在体外，EMT是由 不同数量的细胞因子和环境因素；然而，我们假设肾脏EMT 代表由三个主要转录网络驱动的亚稳态：转化生长因子-β/Smad； 钙粘蛋白/β-连环蛋白/Wnt/Lef/Tcf；和MAPK/ERK信号转导通路。我们已经确定了两种基质金属蛋白酶-2 和MT1-MMPs作为MAPK/ERK信号转导的转录靶点，并确定a 特定的AP-1复杂成分Fra-2足以驱动体外EMT的过程。初级阶段 这一提议的假设是，持续的MAPK/ERK信号，伴随着Fra-2的增强生成，驱动 肾脏EMT所需的一组特定基因的转录。解决这个问题的方法包括 提出利用微阵列分析来表征一系列FrA-2调控基因的三个具体目标 克隆的上皮细胞群体显示出一系列上皮到间充质的特征。这个 已确定基因的功能意义将使用体外和体内方法进行验证，包括 肾近端表达活性基质金属蛋白酶-2基因诱导的独特的肾脏EMT模型 小管。最后，FRA-2单独在体内诱导EMT的能力将通过转基因近端进行测试。 该转录因子在小管中的表达。这些研究旨在确定所需的基因集 从而有望为肾脏疾病的治疗提供新的治疗靶点。

Interstitial fibrosis and tubular atrophy are the hallmarks of all forms of progressive renal fibrosis. This laboratory has focused over the past decade on the role of specific matrix metalloproteinases (MMP-2 and MT1-MMP) in this process. MMP-2, in conjuction with MT1-MMP, is sufficient to induce the conversion of the polarized epithelial cell to a fibroblastic phenotype, a processtermed epithelial mesenchymal transition (EMT). Quantitatively, EMT, in conjunction with activation and expansion of the interstitial fibroblast population, is a major contributor to tubular atrophy and progressiverenal fibrosis. In vitro, EMT is driven by a diverse number of cytokines and environmental factors; however, we have postulated that renal EMT represents a metastable state driven by three dominant transcriptional networks: TGF-beta/Smad; E- cadherin/beta-catenin/Wnt/LEF/TCF; and MAPK/ERKsignaling cascades. We have identified both MMP-2 and MT1-MMP as transcriptional targets of the MAPK/ERKsignaling cascades and determined that a specific AP-1 complex component, Fra-2, is sufficient to drive the process of EMT in vitro. The primary hypothesis of this proposal is that sustained MAPK/ERK signaling, with enhanced generation of Fra-2, drives the transcription of a defined cohort of genes required for renal EMT. The approaches to this problem include three Specific Aims proposing to characterize, using microarray analysis, Fra-2-regulated genes in a series of clonal populations of epithelial cells displaying a range of epithelial to mesenchymal features. The functional significance of identified genes will be validated using in vitro and in vivo approaches, including a unique model of renal EMT generated by the transgenic expressionof active MMP-2 in the renal proximal tubule. Finally, the ability of Fra-2, alone, to induce EMT in vivo will be tested by the transgenic proximal tubule expression of this transcription factor. These studies are designed to identify those gene sets required for renal EMT and thereby hopefully provide new therapeutic targetsfor the treatment of renal disease.