Characterization of the role of mesenchymal Hox5 genes in alveologenesis

间充质 Hox5 基因在肺泡发生中作用的表征

基本信息

批准号：
9928996
负责人：
Leilani Marie Marty-Santos
金额：
$ 6.37万
依托单位：
UNIVERSITY OF WISCONSIN-MADISON
依托单位国家：
美国
项目类别：
财政年份：
2018
资助国家：
美国
起止时间：
2018-06-01 至 2021-05-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/9928996
关键词：
Adherence Adhesions Air Sacs Alleles Alveolar Animals Area Automobile Driving Basement membrane Behavior Binding Birth Breathing Bronchopulmonary Dysplasia Bypass Categories Cell Adhesion Characteristics Chronic lung disease Collagen Data Data Analyses Defect Deposition Development Disease Distal Elastin Embryo Epithelial Epithelium Event Exhibits Extracellular Matrix Fibroblasts Fibronectins Fibrosis Gases Gene Expression Generations Genes Genetic Health system Histologic Human Immunofluorescence Immunologic Impairment In Vitro Infant Integrin alpha5 Integrins Knock-out Knowledge Laboratories Lead Lung Lung diseases Maintenance Mechanical ventilation Mechanics Mediating Mesenchymal Mesenchyme Molecular Morphology Mutant Strains Mice Myofibroblast Neonatal Oxygen Therapy Care Perinatal mortality demographics Play Premature Infant Process Production Publishing Regulation Role Shapes Stretching Structure Surface Western Blotting Work base conditional mutant experimental group in vivo interstitial loss of function lung development mutant novel paralogous gene postnatal prevent transcription factor transcriptome sequencing

项目摘要

ABSTRACT Alveologenesis occurs during the last stage of lung development and is responsible for subdividing the terminal airways of the lungs into alveoli, structures that are critical for efficient gas exchange in the lung. Defects in this process lead to the formation of simplified alveoli that are a hallmark of bronchopulmonary dysplasia (BPD), a chronic lung disease that presents in premature infants treated with mechanical ventilation or oxygen therapy. Although the molecular mechanisms that regulate alveolar development during postnatal stages are unknown, mesodermally-derived fibroblasts in the lung mesenchyme have been shown to be critical drivers of alveologenesis. Published work from our laboratory has demonstrated that all three Hox5 genes (HoxA5, HoxB5 and HoxC5) are exclusively expressed in the lung mesenchyme, and loss of all three Hox5 genes leads to severe developmental lung defects and perinatal death. Four-allele, compound Hox5 mutant mice (Hox5 AabbCc) are born in Mendelian ratios and their lungs are histologically normal at birth, however, they develop alveolar simplification at postnatal stages. Consistent with a direct role for Hox5 genes in alveologenesis, the expression levels of all three Hox5 genes peak during the postnatal stages when alveologenesis is at its peak. Our laboratory has recently generated a conditional allele for Hoxa5, allowing us to bypass the neonatal lethality and assess the post-embryonic functions of this group of regulators. Conditional deletion of Hoxa5 in the lung mesenchyme beginning at birth results in alveolar simplification postnatally. The addition of null alleles for Hoxb5 and Hoxc5 exacerbate this defect. Hox5 conditional mutant lungs exhibit abnormal myofibroblast distribution, shape and impaired function, and the elastin network required for proper alveologenesis fails to form. Unbiased RNAseq analyses reveal gene expression changes in categories associated with cell adhesion and extracellular matrix. Immunofluorescence and western blot analyses demonstrate that both the basement membrane and extracellular matrix components are expressed normally in Hox5 conditional mutants. However, mutant fibroblasts exhibit significant adhesion defects in culture, and preliminary data show loss of Integrin5 expression in fibroblasts derived from Hox5 conditional mutants. Collectively, our data indicate that Hox5 genes regulate the proper differentiation and function of mesenchymal fibroblasts and control lung matrix formation critical for alveologenesis. Using genetics, I plan to elucidate the cellular and molecular mechanisms of Hox5 regulation of lung mesenchyme in alveologenesis.

抽象的肺泡发生发生在肺发育的最后阶段，负责将肺部的终末气道细分为肺泡，这是高效呼吸的关键结构肺部气体交换的缺陷会导致简化的肺泡的形成。是支气管肺发育不良（BPD）的一个标志，这是一种慢性肺部疾病，出现在早产儿虽然接受机械通气或氧疗治疗。出生后阶段调节肺泡发育的机制尚不清楚，肺间充质中的中胚层来源的成纤维细胞已被证明至关重要我们实验室发表的研究表明，这三个因素都是肺泡发生的驱动因素。 Hox5 基因（HoxA5、HoxB5 和 HoxC5）仅在肺间质中表达，所有三个 Hox5 基因的缺失会导致严重的发育性肺缺陷和围产期四等位基因、复合 Hox5 突变小鼠 (Hox5 AabbCc) 以孟德尔比例出生。他们的肺部在出生时组织学上是正常的，然而，他们在出生时就出现了肺泡简化出生后阶段，与 Hox5 基因在肺泡发生中的直接作用一致。所有三个 Hox5 基因的水平在出生后阶段达到峰值，此时肺泡发生处于鼎盛时期我们的实验室最近生成了 Hoxa5 的条件等位基因，使我们能够绕过新生儿致死率并评估这组胚胎的后胚胎功能从出生时开始就有条件地删除肺间质中的 Hoxa5 会导致 Hoxb5 和 Hoxc5 无效等位基因的添加加剧了出生后肺泡的简化。 Hox5条件突变肺表现出异常的肌成纤维细胞分布、形状。和功能受损，并且正常肺泡生成所需的弹性蛋白网络无法形成。无偏 RNAseq 分析揭示与细胞相关类别的基因表达变化粘附和细胞外基质。免疫荧光和蛋白质印迹分析证明。基底膜和细胞外基质成分均正常表达然而，在Hox5条件突变体中，突变体成纤维细胞表现出显着的粘附缺陷。培养物，初步数据显示来自来源的成纤维细胞中整合素α5表达丧失总的来说，我们的数据表明 Hox5 基因调节适当的突变体。间充质成纤维细胞的分化和功能以及控制肺基质形成至关重要对于肺泡发生，我计划阐明其细胞和分子机制。 Hox5 对肺泡发生中肺间质的调节。