Role of HIF-1alpha in Fetal Lung Epithelial Differentiation

HIF-1α 在胎儿肺上皮分化中的作用

• 批准号: 7574457
• 负责人: JOHN M SHANNON
• 金额: $ 53.84万
• 依托单位: CINCINNATI CHILDRENS HOSP MED CTR
• 依托单位国家: 美国
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-02-01 至 2012-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7574457
• 关键词: A Mouse; ABCA3 gene; Affect; Air; Alveolar; Anabolism; Animals; Atelectasis; Binding; Biological Assay; Birth; Breathing; Breeding; Cell Differentiation process; Cell Maturation; Data; Development; Distal; Dominant-Negative Mutation; EMSA; Environment; Enzymes; Epithelial; Epithelial Cells; Epithelium; Fetal Lung; Fetus; Gene Expression; Gene Targeting; Genes; Genetic Transcription; Gestational Age; Glycogen; Glycolysis; HIF1A gene; Hypoxia; Hypoxia Inducible Factor; In Vitro; Link; Lipids; Liquid substance; Lung; Mediating; Modeling; Molecular; Mus; Phenotype; Phospholipids; Play; Pregnancy; Process; Production; Promoter Regions; Proteins; Pulmonary Surfactant-Associated Protein B; Pulmonary Surfactants; Regulation; Research Personnel; Respiratory Failure; Respiratory physiology; Response Elements; Role; Site; Staging; Surface; Surface Tension; System; Testing; Time; Tissues; Transgenes; Transgenic Mice; Transgenic Model; Type II Epithelial Receptor Cell; alveolar lamellar body; alveolar type II cell; critical period; glucose uptake; in utero; in vivo; lipid transport; lung development; lung maturation; mouse model; neonatal death; neonate; postnatal; prenatal; programs; promoter; respiratory distress syndrome; restoration; surfactant

DESCRIPTION (provided by applicant): Pulmonary surfactant, which is synthesized and secreted by alveolar type II cells, reduces surface tension at the air-liquid interface. The critical importance of pulmonary surfactant to normal lung function is underscored by the fact that a deficiency in pulmonary surfactant has been incontrovertibly linked to respiratory distress syndrome (RDS) in neonates. Synthesis and storage of pulmonary surfactant increase dramatically at the end of gestation. The molecular regulation of type II cell maturation, however, is not yet completely understood. Our preliminary data demonstrate that hypoxia inducible factor-la (HIF-1() plays an important role in lung epithelial differentiation. Cre-mediated deletion of HIF-1( in lung epithelial cells results in neonatal death from respiratory failure. Lungs from affected animals show significant reductions in several key components of the surfactant system. The present proposal will test the hypothesis that the hypoxic environment in utero is critical for increased surfactant production at the end of gestation, and that HIF-1( regulates key aspects of this process. We will examine the mechanism(s) by which HIF-1( influences lung epithelial cell differentiation in three specific aims. In the first specific aim we will use a transgenic model to determine how lung-specific HIF-1( deletion regulates overall surfactant phospholipid biosynthesis. Our preliminary data also indicate that expression of surfactant protein B (SP-B) and the lipid transporter ABCA3 are decreased in the epithelium of mice in which HIF-1( has been deleted. In the second specific aim we will use mice with lung-specific HIF-1( deletion to determine the role of HIF-1( in the regulation of SP-B and ABCA3. We will test the ability of HIF-1( to directly activate SP-B and ABCA3 transcription in vitro and define its interactions with hypoxia response elements. We will use a transgenic mouse model in which a constitutively active form of HIF-1( is inducibly expressed in the lung epithelium to determine if the effects of HIF-1( on SP-B and ABCA3 expression are direct. In third specific aim, we will express an inducible, dominant-negative form of HIF-1( in the lung epithelium to determine if HIF-1( is critical during particular periods of lung development. We will also use this model to determine if conditionally expressed SP-B or ABCA3 can reverse the HIF-l(-deleted phenotype. By defining the role of HIF-1(, these studies will provide important new information about the regulation of distal lung epithelial differentiation.

描述（由申请人提供）：肺表面活性物质由肺泡II型细胞合成和分泌，可降低气液界面的表面张力。肺表面活性物质缺乏与新生儿呼吸窘迫综合征（RDS）的发生有着不可否认的联系，这一事实强调了肺表面活性物质对正常肺功能的重要性。肺表面活性物质的合成和储存在妊娠末期急剧增加。然而，II型细胞成熟的分子调控尚未完全理解。我们的初步数据表明，缺氧诱导因子-1（HIF-1）在肺上皮分化中起重要作用。Cre介导的肺上皮细胞HIF-1缺失导致新生儿呼吸衰竭死亡。受影响动物的肺显示表面活性剂系统的几个关键组分显著减少。目前的建议将测试的假设，即在子宫内的缺氧环境是至关重要的增加表面活性剂的生产在妊娠结束时，和HIF-1（调节这一过程的关键方面。我们将从三个方面研究HIF-1影响肺上皮细胞分化的机制。在第一个具体目标中，我们将使用转基因模型来确定肺特异性HIF-1（缺失）如何调节整体表面活性剂磷脂生物合成。我们的初步数据还表明，表面活性蛋白B（SP-B）和脂质转运蛋白ABCA 3的表达在HIF-1 α缺失的小鼠上皮中降低。在第二个具体目标中，我们将使用具有肺特异性HIF-1（缺失）的小鼠来确定HIF-1（在SP-B和ABCA 3的调节中）的作用。我们将测试HIF-1在体外直接激活SP-B和ABCA 3转录的能力，并确定其与缺氧反应元件的相互作用。我们将使用转基因小鼠模型，其中HIF-1 α的组成型活性形式在肺上皮中诱导表达，以确定HIF-1 α对SP-B和ABCA 3表达的影响是否是直接的。在第三个具体目标中，我们将在肺上皮中表达诱导型显性阴性形式的HIF-1，以确定HIF-1在肺发育的特定时期是否至关重要。我们还将使用该模型来确定条件表达的SP-B或ABCA 3是否可以逆转HIF-1 α缺失的表型。通过确定HIF-1 α的作用，这些研究将提供有关远端肺上皮分化调控的重要新信息。