Mechanisms of Pulmonary Microbiota-Induced Inflammation and Vascular Dysfunction in Neonatal Lung Injury

项目摘要/摘要： 这份修订后的NIH K08提案描述了一名内科医生候选人的5年培训和研究计划 科学家的长期目标是成为新生儿肺部疾病领域的独立研究者 具有了解肺微生物群在慢性肺部疾病中的作用的专业知识的生物学 早产儿。为了实现这一目标，他和他的指导委员会提出了一个完整的职业生涯 包含一个新的研究想法的发展计划。 支气管肺发育不良(BPD)，极早产儿最常见的肺部发病率是 早期中性粒细胞涌入、胶原降解、重塑和动脉对未成熟肺的损伤 变厚了。候选人发现，新生儿的呼吸道并不是无菌的，而是被 甚至在出生时就有多样化的微生物群，并且微生物群在发育过程中发生了变化(生物失调)。 每桶。他最近还发现了外体microRNAs在BPD预测和发病机制中的作用。 他的导师此前已经证实，N-乙酰脯氨酸-甘氨酸-脯氨酸(Ac-PGP)三肽源于 从ECM的分解来看，ECM通过增强中性粒细胞在各种慢性肺部疾病中起关键作用 炎症和内皮通透性。这项提案中的初步数据表明， 患有BPD的婴儿增加了丙种蛋白细菌(-Protebacteria)的水平，也增加了 AC-PGP。此外，Ac-Pgp功能的增强在小鼠模型中创造了BPD的表型，而 AC-PGP功能逆转BPD表型。基质金属蛋白酶9(MMP9)与脯氨酰内肽酶 (PE)降解胶原，导致Ac-Pgp的释放。MMP9和PE是胞外体的首选预测靶点 MIR 548M和MIR 129-1-3，这两个MIR在BPD中都减少了。总而言之，这些发现 导致了新的机制假说--变形杆菌诱导的外体MIR减少 增加蛋白酶水平，进而增加Ac-Pgp的释放，并导致慢性中性粒细胞 BPD的炎症和血管功能障碍。除了确定这些机制(目标1)外， 候选人将使用独立的“发现”和“验证”队列进行一项人体研究 早产儿验证外体miR548m和miR129-1-3p减少和增加的假设 MMP9、PE和Ac-Pgp与呼吸道微生物菌群有关，是严重BPD的早期预测因子(目标2)。 因此，这项研究提案中提出的工作将产生关于以下机制的新信息 微生物区系导致BPD的中性粒细胞炎症和血管功能障碍，并将确定新的早期 BPD的生物标志物。 候选人已经组建了一个智力互补的研究咨询委员会， 内容专业知识，可以在整个颁奖期间指导他。此外，应聘者将获得说教 获得必要知识的教育，最终授予MSPH学位。通过这一集成 指导和教学计划，候选人将获得技能和专业知识在肺部炎症，微生物 发病机制，微核糖核酸和外体分子生物学，微生物组测序，生物信息学，技能 无菌小鼠模型的操作和研究伦理。这将使HIM能够开发出一种 独立研究计划并获得NIH R01资金。

PROJECT SUMMARY/ABSTRACT: This revised NIH K08 proposal describes a 5-year training and research plan for the candidate, a physician scientist with a long term goal of becoming an independent investigator in the field of neonatal pulmonary biology with expertise in understanding the role of the pulmonary microbiome in chronic lung disease of prematurity. To accomplish this goal, he and his mentoring committee put forth an integrated career development plan encompassing a novel research idea. Bronchopulmonary dysplasia (BPD), the most common pulmonary morbidity in extremely preterm infants is initiated by injury to the immature lung by early neutrophil influx, collagen degradation, remodeling, and arterial thickening. The candidate has discovered that the airways of newborn infants are not sterile but are occupied by a diverse microbiome even at birth, and that the microbiome is altered (dysbiosis) during the development of BPD. He has also recently discovered the role of exosomal microRNAs in BPD prediction and pathogenesis. His mentors have previously established that the tripeptide N-acetyl proline-glycine-proline (Ac-PGP) derived from the breakdown of the ECM plays a critical role in various chronic lung diseases by enhancing neutrophilic inflammation and endothelial permeability. The preliminary data in this proposal indicate that the airways of infants with BPD which have increased Gammaproteobacteria (¡-Proteobacteria) also have increased levels of Ac-PGP. Moreover, gain of Ac-PGP function creates the phenotype of BPD in murine models, whereas loss of Ac-PGP function reverses the BPD phenotype. Matrix metalloproteinase 9 (MMP9) and prolyl endopeptidase (PE) degrade collagen, leading to the release of Ac-PGP. MMP9 and PE are top predicted targets of exosomal miR 548m and miR 129-1-3 respectively and both these miRs are reduced in BPD. Collectively, these findings lead to the novel mechanistic hypothesis that ¡-Proteobacteria-induced reduction in exosomal miRs increase protease levels which in turn increase Ac-PGP release and cause chronic neutrophilic inflammation and vascular dysfunction in BPD. In addition to determining these mechanisms (Aim 1), the candidate will conduct a human study using independent ‘Discovery’ and ‘Validation’ cohorts of extremely preterm infants to test the hypothesis that decreased exosomal miRs 548m and miR 129- 1-3p and increased MMP9, PE and Ac-PGP, in relation to a dysbiotic airway microbota are early predictors of severe BPD (Aim 2). Thus the work proposed in this research proposal will generate novel information about the mechanisms of microbiota induced neutrophilic inflammation and vascular dysfunction in BPD, and will determine novel early biomarkers for BPD. The candidate has already assembled a research advisory committee with complementary intellect and content expertise that can guide him throughout the award period. In addition, the candidate will obtain didactic education to gain requisite knowledge culminating in the awarding of an MSPH degree. Through this integrated mentoring and didactic plan, the candidate will gain skill and expertise in pulmonary inflammation, microbial pathogenesis, microRNA and exosomal molecular biology, microbiome sequencing, bioinformatics, skills in manipulation of germ free mouse models and research ethics. This will enable the him to develop an independent research program and obtain NIH R01 funding.