Regulation of Elastin Assembly during Saccular Stage Lung Development

肺囊期发育过程中弹性蛋白组装的调节

• 批准号: 9386272
• 负责人: JOHN BENJAMIN
• 金额: $ 14.78万
• 依托单位: VANDERBILT UNIVERSITY MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-07-05 至 2022-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9386272
• 关键词: Address; Adult; Affect; Air Sacs; Amniotic Fluid; Amniotic Sac; Aspirate substance; Bronchoalveolar Lavage Fluid; Bronchopulmonary Dysplasia; Data; Development; Distal; Down-Regulation; Elastic Fiber; Elastin; Environment; Epithelial; FBLN5 gene; Fetal Lung; Fibroblasts; Future; Impairment; In Vitro; Infant; Inflammation; Inflammatory; Interleukin-1; Interleukin-1 alpha; Interleukin-1 beta; Knowledge; Link; Liquid substance; Long-Term Effects; Lung; Lung diseases; Mediating; Mediator of activation protein; Mesenchymal; Modeling; Morbidity - disease rate; Mus; Pathogenesis; Pathway interactions; Perinatal; Phenotype; Positioning Attribute; Predisposition; Premature Infant; Production; Publishing; Regulation; Reporter; Reporting; Risk Factors; Role; Signal Transduction; Stimulus; Structure; Testing; Therapeutic; Time; Transcriptional Regulation; Transgenic Mice; adenoviral-mediated; airway epithelium; antenatal; cell type; chromatin immunoprecipitation; emergency service responder; fetal; in vivo; inhibitor/antagonist; insight; interstitial; intraamniotic infection; lung development; mRNA Expression; microbial; mouse model; novel; overexpression; postnatal; premature; premature lungs; prevent; promoter; pulmonary function; respiratory; response; therapeutic development; transcription factor

PROJECT SUMMARY Perinatal inflammation is an established risk factor for bronchopulmonary dysplasia (BPD), a major morbidity of prematurity characterized by abnormal saccular stage lung development. As the airway epithelium is present at the interface of the amniotic sac environment and the fetal lung, it is well positioned to respond to inflammatory stimuli in amniotic fluid. Therefore, we developed a transgenic mouse model to inducibly express the master inflammatory transcription factor NF-κB, in the airway epithelium (IKTA mice). Using this model, we showed that epithelial-derived inflammation results in profound dilation of terminal airspaces during the saccular stage, but does not alter earlier stages of lung development. Airspace dilation in saccular stage IKTA lungs was associated with reduced expression of important elastin assembly components, especially fibulin-5, by interstitial fibroblasts, leading to altered elastic fiber assembly around distal airspaces. In new preliminary data generated to identify epithelial-derived inhibitors of elastin assembly components in fibroblasts, we found that lungs of IKTA mice and tracheal aspirates (TA) from preterm infants exposed to antenatal inflammation had high levels of IL-1 (both IL- 1α and IL-1β). Neutralizing IL-1α or IL-1β restored fibulin-5 expression in fibroblasts exposed to bronchoalveolar lavage fluid (BAL) from IKTA mice or TA from preterm infants. Since IL-1 triggers intracellular signaling via NF- κB, we tested the direct impact of NF-κB on saccular stage lung fibroblasts and observed that NF-κB signaling inhibited fibulin-5 mRNA expression. Finally, by modifying our transgenic mouse model to enable survival beyond the early postnatal period, we found that inflammation-induced disruption in saccular stage elastin organization results in persistent abnormalities in lung structure. Proposed studies will test the hypothesis that during the saccular stage of lung development, epithelial-derived inflammation propagates down-stream NF-κB activation in fibroblasts through IL-1 signaling, resulting in down-regulation of fibulin-5 and other critical elastin assembly components. Disruption of elastin organization during this critical developmental window impairs lung development, leading to abnormalities in lung structure and function that persist into adulthood. Specific aims are: 1) to define the role of IL-1 signaling in regulation of elastic fiber assembly components, 2) to determine the transcriptional regulation of fibulin-5 in lung fibroblasts during development and in response to inflammation, and 3) to investigate the long-term impact of impaired saccular stage elastin assembly. Together, our studies will determine how inflammation during a critical developmental window can modulate lung structure and function, thus providing new insights into BPD pathogenesis and the long-term consequences of altered saccular stage lung development.

项目摘要 围产期炎症是支气管肺发育不良（BPD）的确定危险因素，这是一个主要的发病率 早产性为特征，以异常的肺泡肺发育。由于气道上皮存在 羊膜囊环境和胎儿肺的界面，对炎症的反应很好 羊水刺激。因此，我们开发了一种转基因小鼠模型来诱导表达主 气道上皮（IKTA小鼠）中的炎症转录因子NF-κB。使用此模型，我们表明 上皮衍生的炎症导致临时阶段的末端空间的深刻字典，但 不会改变肺发育的早期阶段。 SACCULAR阶段IKTA肺的空体扩张是相关的 通过间质成纤维细胞的重要弹性蛋白组件成分（尤其是菲林5）的表达降低， 导致远端空域周围的弹性纤维组件发生变化。在生成的新初步数据中 成纤维细胞中弹性蛋白组件成分的上皮源性抑制剂，我们发现Ikta小鼠的肺和 暴露于触角注射的早产儿的气管吸入（TA）具有高水平的IL-1（均IL- 1α和IL-1β）。中和IL-1α或IL-1β在暴露于支气管肺泡的成纤维细胞中恢复了纤维蛋白5的表达 来自IKTA小鼠或早产儿的TA的灌洗液（BAL）。由于IL-1通过NF-触发细胞内信号传导 κB，我们测试了NF-κB对圆形阶段肺成纤维细胞的直接影响，并观察到NF-κB信号传导 抑制斐杜蛋白-5 mRNA表达。最后，通过修改我们的转基因小鼠模型以使生存超越 出生后早期，我们发现炎症引起的囊肿弹性蛋白组织的破坏 导致肺结构持续异常。拟议的研究将检验以下假设。 肺发育的暂时阶段，上皮源性炎症传播了下游NF-κB激活 在通过IL-1信号传导的成纤维细胞中，导致腓蛋白5和其他临界弹性蛋白组装的下调 成分。在这个关键的发展窗口中，弹性组织的破坏会损害肺 发育，导致肺结构和功能的异常，直至成年。具体目标 为：1）定义IL-1信号在调节弹性纤维组件组件中的作用，2）确定 在发育和响应炎症的过程中，fibulin-5在肺成纤维细胞中的转录调节，以及 3）研究糖果阶段弹性蛋白组装受损的长期影响。一起，我们的研究将 确定关键发育窗口中的注射如何调节肺结构和功能， 因此，提供了对BPD发病机理的新见解和改变的临床阶段的长期后果 肺发育。