LUNG ALVEOLAR TYPE 1 CELL MORPHOGENESIS

肺泡 1 型细胞形态发生

• 批准号: 7145832
• 负责人: Maria Isabel Ramirez
• 金额: $ 40.63万
• 依托单位: BOSTON UNIVERSITY MEDICAL CAMPUS
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-07-01 至 2011-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7145832
• 关键词: Caenorhabditis elegans; Drosophilidae; cell differentiation; cell morphology; developmental genetics; flow cytometry; gene expression profiling; green fluorescent proteins; laboratory mouse; lung development; respiratory epithelium; small interfering RNA; tissue /cell culture; transcription factor; transfection

DESCRIPTION (provided by applicant): The objective of this proposal is to define the molecular mechanisms of lung alveolar type I cell development, focusing on one of the principal features of type I cells, their extensive, thin, flat shape. In late gestation, precursor distal lung epithelial cells change their shape from cuboidal to flat, acquiring the structural and molecular features of differentiated type I cells to form the thin alveolar gas exchange surface. We hypothesize that genes that regulate plasma membrane growth and polarization, and cytoskeletal organization play a critical inductive and/or permissive role in the process of late fetal type I cell development. We will analyze three important features of alveolar type I cells: shape, type I specific gene expression, and flattening-related gene expression. We will selectively modify each of these features and study alterations in the other two. This approach will provide important information about the molecular mechanisms that initiate and/or sustain type I cell morphogenesis. We will study in the developing lung the roles of genes associated with epithelial cell expansion and flattening identified in Drosophila and C. elegans, and of genes associated with altered cell shape in T1a null mutant mouse, where type I cell formation is impaired. We will determine when and where these genes are expressed in normal lung. We will evaluate their role in cell flattening and spreading using type l-precursor cells isolated at different developmental stages from fetal lungs expressing GFP driven by the promoter of the type I cell gene T1a. We will increase or reduce expression of selected genes in vitro to determine effects on epithelial cell flattening and spreading and on type I specific gene expression. We will modulate the shape of epithelial cells in vitro using culture conditions that restrict spreading and evaluate type I specific and cell-flattening-related gene expression. Finally, we will evaluate the role of these genes in vivo using developing lungs with impaired type I cell differentiation. Analysis of type I cells by these approaches will provide new insights into the regulation of type I cell formation in the fetal lung. This regulation is likely important for type I cell morphogenesis in postnatal lung growth and in lung repair after injury in the adult lung. Relevance to Public Health: When lung development is delayed or babies are delivered prematurely the cells that line the lung alveoli are immature and cannot efficiently perform the normal process of gas exchange. Identifying the key genes that control alveolar cell formation is important to allow the design of new treatments to stimulate newborn lung maturation. Similar mechanisms could apply to the process of alveolar cell healing after injuries caused by infections or environmental factors. Therefore these studies will provide new understanding of the regulation of type I formation that likely will improve treatment of acute and chronic lung diseases in the adult.

描述（由申请人提供）：该提案的目的是定义肺肺泡I型细胞发育的分子机制，重点是I型细胞的主要特征之一，它们的广泛，较薄，扁平的形状。在妊娠晚期，前体远端肺上皮细胞将其形状从立方体变为平坦，从而获得了分化I型细胞的结构和分子特征，形成了稀薄的肺泡气体交换表面。我们假设调节质膜生长和极化的基因在胎儿晚期I型细胞发育过程中起着关键的感应性和/或允许性作用。我们将分析牙槽I型细胞的三个重要特征：形状，I型特异性基因表达和与扁平的基因表达。我们将有选择地修改这些功能，并研究其他两个特征。这种方法将提供有关启动和/或维持I型细胞形态发生的分子机制的重要信息。我们将研究与果蝇和秀丽隐杆线虫中上皮细胞膨胀和扁平化相关的基因的作用，以及与I型细胞形成受损的T1A无效突变小鼠中与细胞形状改变相关的基因。我们将确定在正常肺中表达这些基因的何时何地。我们将使用在不同发育阶段分离的L型Lung肺部驱动的GFP的Lungs启动子驱动子T1A启动子的胎儿肺部分离出的L型L型细胞在细胞平坦和扩散中的作用。我们将在体外增加或减少所选基因的表达，以确定对上皮细胞扁平和扩散以及I型特异性基因表达的影响。我们将使用限制扩散和评估与I型特异性和细胞贴剂相关的基因表达的培养条件在体外调节上皮细胞的形状。最后，我们将使用具有I型细胞分化受损的发育中的肺在体内评估这些基因的作用。通过这些方法对I型细胞进行分析将为胎儿肺中I型细胞形成的调节提供新的见解。该调节对于成年肺损伤后肺部生长和肺修复中I型细胞形态发生可能很重要。与公共卫生有关：延迟肺部发育或过早输送婴儿时，将肺肺泡的细胞不成熟，无法有效地执行正常的气体交换过程。识别控制肺泡细胞形成的关键基因对于允许设计新疗法刺激新生儿肺部成熟很重要。类似的机制可能适用于感染或环境因素引起的损伤后肺泡细胞愈合的过程。因此，这些研究将提供对I型形成的调节的新理解，这些调节可能会改善成人急性和慢性肺部疾病的治疗。