RESPIRATORY EPITHELIAL CELL DIFFERENTIATION (TTF-1, HNF-3B)

（申请人摘要）本项目旨在继续开展活动， 确定的机制的阐明，1）前肠的承诺 内胚层形成胚肺，2）增殖和分化， 发育中的肺中呼吸细胞的不同亚群，以及3） 肺损伤后呼吸道上皮细胞的增殖和重塑 损伤这一申请是基于过去四年来取得的进展， 这表明了三个不同的关键，相互作用的作用 转录因子家族，即TTF-1（同源结构域）、HNF-3 β和 呼吸道上皮细胞中的HFH-4（翅状螺旋）和加塔-6（锌指） 谱系定型和肺形态发生。本提案将 确定这些基因中的两个的精确时间/空间要求 （HNF-3 β和TTF-1）在肺形成中的作用，并将决定其 对呼吸道上皮细胞分化、基因表达和 分枝形态发生该研究计划是基于成功的 条件性肺特异性CRE重组酶技术的开发 介导的基因删除和添加，技术， 上皮细胞谱系分析和位点特异性基因靶向。基因 编码TTF-1和HNF-3 β的基因将经受cre-重组酶介导的 在发育过程中的精确时间缺失，诱导cre重组酶， 强力霉素控制的肺特异性条件系统。时空 重组介导的TTF-1和HNF-3 β缺失对肺组织的影响 将辨别形态发生。呼吸道上皮细胞分化 HNF-3 β和TTF-1靶基因的表达将在 体内和体外。Cre重组酶和逆转录病毒介导的细胞标记 祖细胞将用于定义呼吸系统谱系图 在体内正常发育的肺中的上皮。TTF-1和HNF-3 β的作用 肺形态发生和呼吸道上皮细胞缺失 将在产前和产后辨别差异。的影响 降低TTF-1和HNF-3 β对细胞增殖和分化的影响 氧损伤的修复将被识别。专题信托基金-1和 HNF-3 β在肺畸形和支气管肺炎发病机制中的作用 发育不良（BPD）和其他形式的慢性肺病将寻求在 人类研究

(Applicant's Abstract) This project seeks to continue activities focused to the elucidation of mechanisms which determine, 1) commitment of foregut endoderm to form the embryonic lung, 2) proliferation and differentiation of distinct subsets for respiratory cells in the developing lung and 3) proliferation and remodeling of the respiratory epithelium following lung injury. This application is based on progress made in the last four years of funding which demonstrated critical, interacting roles of three distinct families of transcription factors, namely TTF-1 (homeodomain), HNF-3beta and HFH-4 (winged helix) and GATA-6 (zinc finger) in respiratory epithelial cell lineage commitment and lung morphogenesis. The present proposal will determine the precise temporal/spatial requirements for two of these genes (HNF-3beta and TTF-1) in formation of the lung and will determine their influence on respiratory epithelial cell differentiation, gene expression and branching morphogenesis. The research plan is based on the successful development of technology for conditional, lung-specific cre-recombinase mediated gene deletion and addition, technology that will enable respiratory epithelial cell lineage analysis and site-specific gene targeting. Genes encoding TTF-1 and HNF-3beta will be subjected to cre-recombinase mediated deletion at precise times during development, inducing cre-recombinase with a doxycycline-controlled lung-specific conditional system. Temporal and spatial effects of recombination mediated deletion of TTF-1 and HNF-3beta on lung morphogenesis will be discerned. Respiratory epithelial cell differentiation and the expression of HNF-3beta and TTF-1 target genes will be assessed in vivo and in vitro. Cre-recombinase and retroviral mediated cell marking of progenitor cells will be used to define a lineage map of the respiratory epithelium in the normal developing lung in vivo. Effects of TTF-1 and HNF-3beta deletion on lung morphogenesis and respiratory epithelial cell differentiation will be discerned prenatally and postnatally. Effects of decreased TTF-1 and HNF-3beta on cell proliferation and differentiation during repair from oxygen injury will be discerned. Potential roles of TTF-1 and HNF-3beta in the pathogenesis of lung malformation and bronchopulmonary dysplasia (BPD) and other forms of chronic lung disease will be sought in human studies.