FGF-7 (KGF) AND RECEPTORS IN LUNG MORPHOGENESIS AND REPAIR

该项目是基于观察， 成纤维细胞生长因子受体-2（FGFR-2）-角质形成细胞生长因子 (KGF)在肺轴产生深刻的异常分支 形态发生和肺生长。新生儿 转基因小鼠表达显性阴性FGFR-2（FGFR-2dn）， 原始肺上皮显示严重的肺发育不全 而在发育中表达高水平KGF的转基因小鼠， 肺在子宫内死亡，伴有大量气道扩张和肺泡紊乱 阵本项目的研究基于以下假设： 需要KGF表达的精确时间/空间调节 成功的肺发育和氧损伤后的修复。 KGF表达在肺内的定位将在实验中确定。 胚胎、新生和成年小鼠的原位杂交。体外 并利用体内模型建立了控制 特异性肺KGF mRNA表达。KGF的表观遗传控制 将使用体外细胞培养模型测定表达， 瞬时转染试验和转基因小鼠模型。物理 确定鼠KGF基因座的结构， 鉴定介导KGF表达的顺式和反式活性因子 在肺部。氧刺激对KGF表达的调节机制 将识别新生和成年动物的损伤。转基因 在对照下表达嵌合四环素反式激活因子的小鼠 SP-C启动子的启动子将用于暂时控制表达 KGF或FGFR-2dn，从而调节KGF/FGFR-2轴 在整个发展中。形态学和生理学研究将 补充了对肺结构和细胞组成的分析， 转基因诱导的背景。这些研究将确定 和KGF在肺中表达的基础，并确定 与异常KGF相关的有害和有益后果 在发育和损伤过程中表达。与人类疾病的相关性 可能与KGF表达异常相关的状态， 囊腺瘤样畸形和支气管肺发育不良将促进 了解其发病机制和新的机会， 治疗方法。

This project is based upon the observation that disruption of the fibroblast growth factor receptor-2 (FGFR-2)-keratinocyte growth factor (KGF) axis in the lung produces profound abnormalities of branching morphogenesis and lung growth during fetal mouse development. Newborn transgenic mice expressing a dominant negative FGFR-2 (FGFR-2dn) in the primordial pulmonary epithelium display severe pulmonary hypoplasia while transgenic mice expressing high levels of KGF in the developing lung die in utero with massive airway dilatation and disordered alveolar formation. Studies in this project are based upon the hypothesis that the precise temporal/spatial regulation of KGF expression is required for successful lung development and repair following oxygen injury. Localization of KGF expression within the lung will be determined in the fetal, neonatal and adult mouse using in situ hybridization. In vitro and in vivo models are used to establish the mechanisms controlling specific pulmonary KGF mRNA expression. Epigenetic controls of KGF expression will be determined using in vitro cell culture models, transient transfection assays, and transgenic mouse models. The physical structure of the murine KGF locus will be determined in order to identify the cis and trans active factors that mediate KGF expression in the lung. Mechanisms of modulation of KGF expression following oxygen injury in the newborn and adult animal will be identified. Transgenic mice expressing a chimeric tetracycline transactivator under the control of the SP-C promoter will be used to temporally control the expression of KGF or FGFR-2dn in the lung, thus modulating the KGF/FGFR-2 axis throughout development. Morphometric and physiologic studies will complement an analysis of lung structure and cellular composition in the context of transgene induction. These studies will define the location and basis for expression of KGF in the lung and determine the consequences, detrimental and beneficial, associated with aberrant KGF expression during development and injury. Correlation with human disease states likely to be associated with aberrant KGF expression such as cystadenomatoid malformation and bronchopulmonary dysplasia will promote understanding of their pathogenesis and opportunities for novel therapeutic approaches.