Integrated Molecular and Cellular Drivers of Alveologenesis

肺泡发生的综合分子和细胞驱动因素

基本信息

批准号：
10637764
负责人：
Jennifer MalcolmSrygley Sucre
金额：
$ 72.89万
依托单位：
VANDERBILT UNIVERSITY MEDICAL CENTER
依托单位国家：
美国
项目类别：
财政年份：
2023
资助国家：
美国
起止时间：
2023-05-20 至 2028-04-30
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10637764
关键词：
Ablation Agonist Alveolar Alveolus Architecture Blood capillaries Bronchopulmonary Dysplasia Capillary Endothelial Cell Cell Differentiation process Cell Nucleus Cell Proliferation Cells Chromatin Collagen Data Development Distal Endothelial Cells Endotoxins Epithelial Cells Epithelium Extracellular Matrix Extracellular Matrix Proteins Fluorescent in Situ Hybridization Four-dimensional Generations Genetic Transcription Goals Growth Health Human Hyperoxia Image Immunofluorescence Immunologic Impairment Inflammation Injury Knowledge Laminin Libraries Light Lung Mesenchymal Microscopy Modeling Molecular Molecular Target Myofibroblast Pathway interactions Pattern Phenotype Pregnancy Premature Birth Premature Infant Process Production Proliferating Publishing Regulation Reporter Resolution Role Sampling Signal Pathway Signal Transduction Slice Structure Testing Therapeutic Time Transgenic Organisms Visualization WNT Signaling Pathway alveolar epithelium antagonist capillary bed cell motility delivery complications experimental study extracellular high risk in vivo inhibitor innovation lung development lung injury multiple omics neonatal exposure neonatal injury neonatal lung injury neonatal mice neonate new growth novel strategies overexpression postnatal pulmonary function real-time images recruit response restoration scaffold second harmonic spatial relationship spatiotemporal temporal measurement transcriptome sequencing transcriptomics

项目摘要

PROJECT SUMMARY Neonates born during the saccular stage of lung development (23-32 wks gestation) are at highest risk for bronchopulmonary dysplasia (BPD), a leading preterm birth complication. The mechanisms underlying this vulnerability are poorly defined, a knowledge gap we consider foundational to the lack of curative BPD therapies. To understand the irreversibility of arrested alveologenesis in BPD, we require a refined, mechanistic understanding of the normal saccular to alveolar transition. Our preliminary data from 4- dimensional live imaging and single-cell transcriptomics support a new model of alveologenesis in which myofibroblast ring structures support the extrusion of AT2s (alveolar type 2 cells) followed by their differentiation into AT1s (alveolar type 1 cells). According to our model, mature AT1s produce ECM proteins and other factors that recruit specialized endothelial cells to become the alveolar capillary bed. Sequential, spatiotemporally restricted signaling pathways, including Wnt and BMP, coordinate cell movement, proliferation, and architecture. We have developed a neonatal injury model with a phenotype of impaired alveologenesis that is relevant to human BPD by exposing neonatal mice to hyperoxia and inflammation during the saccular stage. Our preliminary data from this model associate overexpression of Wnt5A/Wnt11 with impaired alveologenesis. Post-injury deficits include decreased BMP production and activity in alveolar epithelial cells and impaired AT2 to AT1 cell differentiation and decreased expression of extracellular matrix (ECM) components by AT1 cells. Based on preliminary and published data, we hypothesize that alveologenesis involves formation of a ring of myofibroblasts that express Wnt5a and Wnt 11 to drive AT2 proliferation and promote extrusion through the ring. Subsequent epithelial BMP production down-regulates Wnt, promoting AT2 to AT1 differentiation and generation of an extracellular scaffold for capillary assembly. Injury dysregulates Wnt and Bmp signaling, perturbing the precise spatiotemporal patterning during this critical timeframe and resulting in arrested alveologenesis and long-term functional deficits. We will test this hypothesis in the following specific aims: 1) Define the role of myofibroblast Wnt expression in regulating AT2 proliferation and alveolar development; 2) Characterize mechanisms by which BMP signaling regulates AT2-to-AT1 cell differentiation; 3) Determine the mechanisms whereby nascent AT1 cells generate a scaffold for the developing alveolus. Successful completion of this proposal is anticipated to transform our understanding of alveologenesis, identifying new molecular targets to promote post-injury alveolar restoration and the optimal time windows for deployment of such newly directed therapies.

项目概要肺发育囊状阶段（妊娠 23-32 周）出生的新生儿患此病的风险最高支气管肺发育不良（BPD）是一种主要的早产并发症。这背后的机制脆弱性的定义不明确，我们认为这是缺乏治疗性 BPD 的根本原因疗法。为了了解 BPD 中肺泡生成受阻的不可逆性，我们需要一种精细的、对正常囊泡到肺泡转变的机制的理解。我们的初步数据来自 4- 三维实时成像和单细胞转录组学支持肺泡发生的新模型，其中肌成纤维细胞环结构支持 AT2（肺泡 2 型细胞）的挤出，然后是它们的分化为 AT1（肺泡 1 型细胞）。根据我们的模型，成熟的 AT1 产生 ECM 蛋白以及招募专门的内皮细胞成为肺泡毛细血管床的其他因素。顺序，时空限制的信号通路，包括 Wnt 和 BMP，协调细胞运动，扩散和建筑。我们开发了一种新生儿损伤模型，其表型为受损通过将新生小鼠暴露在高氧和炎症环境中，肺泡发生与人类 BPD 相关囊状阶段。我们从该模型中得到的初步数据将 Wnt5A/Wnt11 的过度表达与肺泡生成受损。损伤后缺陷包括肺泡中 BMP 产生和活动减少上皮细胞和 AT2 向 AT1 细胞分化受损以及细胞外基质表达减少 (ECM) 成分由 AT1 细胞组成。根据初步和已发布的数据，我们假设肺泡发生涉及表达 Wnt5a 和 Wnt 11 以驱动 AT2 的肌成纤维细胞环的形成增殖并促进通过环的挤压。随后上皮 BMP 的产生下调 Wnt，促进 AT2 向 AT1 分化并生成用于毛细血管组装的细胞外支架。损伤导致 Wnt 和 Bmp 信号传导失调，扰乱了这一关键时期的精确时空模式时间框架并导致肺泡发生停滞和长期功能缺陷。我们将测试这个假设的具体目标如下：1）明确肌成纤维细胞Wnt表达在调节中的作用 AT2增殖和肺泡发育； 2) 表征 BMP 信令的机制调节 AT2 至 AT1 细胞分化； 3) 确定新生AT1细胞的机制为发育中的肺泡生成支架。预计该提案的成功完成改变我们对肺泡生成的理解，确定新的分子靶标以促进损伤后的恢复肺泡恢复和部署此类新定向疗法的最佳时间窗口。