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.

抽象的肺单术发生在肺部发育的最后阶段，并负责将肺的末端气道细化为肺泡，这对于有效的结构至关重要肺部的气体交换。在此过程中的缺陷导致形成简化的肺泡是支气管肺发育不良（BPD）的标志，这是一种慢性肺部疾病，呈现在用机械通气或氧疗法治疗的早产婴儿。虽然分子调节产后肺泡发育的机制尚不清楚，肺间隙中的中层衍生的成纤维细胞已被证明是关键的肺单元的驱动因素。我们实验室发表的工作表明这三个 HOX5基因（Hoxa5，Hoxb5和Hoxc5）专门在肺间隙中表达以及所有三个HOX5基因的丧失导致严重的发育性肺部缺陷和围产期死亡。四等位基因，复合HOX5突变小鼠（HOX5 AABBCC）出生于Mendelian比率他们的肺在出生时在组织学上是正常的，但是，它们在产后阶段。与HOX5基因在肺单术中的直接作用一致，表达当肺单术处于肺泡术时，所有三个HOX5基因的水平都达到峰值顶峰。我们的实验室最近为Hoxa5产生了有条件的等位基因，使我们能够绕过新生儿的致死性和评估这一组的胚胎后功能监管机构。肺间隙中Hoxa5的有条件缺失从出生开始导致肺泡清楚。 HOXB5和HOXC5添加无效等位基因这个缺陷。 HOX5条件突变肺暴露于异常的肌纤维细胞分布，形状和功能受损，适当的肺单元所需的弹性蛋白网络未能形成。公正的RNASEQ分析揭示了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地下膜和细胞外基质组件均正常表达在HOX5条件突变体中。然而，突变的成纤维细胞暴露了明显的粘附缺陷培养和初步数据表明，整合素5表达在成纤维细胞中的丧失。 HOX5条件突变体。总的来说，我们的数据表明HOX5基因调节了适当的间质成纤维细胞的分化和功能和控制肺基质形成关键用于肺单元。我计划使用遗传学，阐明 HOX5肺间充质的调节肺单齿。