Role of neonatal lung macrophages in mediating resilience to hyperoxia induced lung injury via TREM2 signaling

摘要/项目总结 支气管肺发育不良（BPD）是一种慢性肺部疾病，是早产儿最常见的主要并发症， 至少四分之一出生时体重不足1 500克的婴儿受到影响。许多早产儿 BPD将继续有持续的呼吸道症状和肺功能下降到成年。这些 BPD的终身并发症造成了严重的健康负担，需要广泛的卫生保健利用。 目前，BPD还没有有效的预防或个性化治疗。不是每个早产儿 发展BPD，BPD易感性的个体差异可能由复杂的相互作用解释 环境、细胞、遗传和表观遗传因素之间的联系。补充供氧，同时 在新生儿期挽救生命，仍然是BPD病理生理学的关键决定因素。不成熟的暴露 肺对增加的氧水平的耐受性激发炎症反应，导致异常的肺发育。 然而，肺免疫细胞，特别是那些参与先天免疫反应的细胞，及其 提供针对BPD的保护的伴随基因表达程序并不完全已知。的 该提案的总体目标是鉴定和表征特定的肺髓样细胞及其基因， 为氧致肺损伤提供保护的项目。我们的假设是先天免疫系统 肺中激活的反应在患有BPD的早产儿和有弹性的早产儿之间存在差异 疾病。基于我们的新发现，髓样细胞上表达的触发受体的功能的遗传缺失 细胞2（TREM2）在高氧诱导的肺损伤中具有保护作用，我们认为抑制TREM2信号通路 可用于调节先天免疫应答以防止异常肺发育。在目标1中， 将采用单细胞RNAseq和TREM2缺陷小鼠来确定TREM2如何调节基因表达， 新生儿高氧暴露后肺损伤的严重程度。在目标2中，我们将应用新的方法， p53缺陷小鼠暴露于新生儿高氧并使用ATACseq和 ChIPseq用于鉴定TREM2通过其指导对受试者的致病性免疫应答的调节机制。 转录水平。最后，为治疗靶向的转化潜力建立原理验证 我们将在体内测试TREM2阻断抗体并评估从室内空气中的高氧中的恢复（目的 3）。进一步研究小鼠和人类之间基因调控途径的保守性，将提供 一个合理的理由来使用这些基因通路来开发靶向治疗。该项目将确定独特的 肺髓样细胞的基因调控网络，支持发育中的再生免疫反应。 肺。这些发现将阐明高氧后新生儿肺弹性的新途径， 多因素BPD的更有针对性的管理的发展。

ABSTRACT/PROJECT SUMMARY Bronchopulmonary dysplasia (BPD), a chronic lung disease, is the most common major complication of preterm birth affecting at least one fourth of infants born with a birth weight less than 1500g. Many premature infants with BPD will continue to have persistent respiratory symptoms and decreased lung function into adulthood. These life-long complications of BPD create significant health burden and necessitate extensive health care utilization. Currently, there is no effective prevention or personalized treatment for BPD. Not every premature infant develops BPD, and this individual variability in BPD susceptibility is likely explained by complex interactions between environmental, cellular, genetic, and epigenetic factors. Supplemental oxygen administration, while lifesaving in the neonatal period, remains a key determinant of BPD pathophysiology. Exposure of the immature lung to increased levels of oxygen elicits an inflammatory response resulting in abnormal lung development. However, the lung immune cells, specifically those involved in the innate immune response, and their accompanying gene expression programs that provide protection against BPD are not completely known. The overall objective of this proposal is to identify and characterize specific lung myeloid cells and their gene programs that provide protection to oxygen-induced lung injury. Our hypothesis is that the innate immune response activated in the lung differs between premature infants who develop BPD and those that are resilient to disease. Based on our novel finding that genetic loss of function of Triggering Receptor Expressed on Myeloid cells 2 (TREM2) is protective in hyperoxia-induced lung injury, we propose that inhibition of TREM2 signaling may be exploited to modulate the innate immune response to prevent abnormal lung development. In Aim 1 we will employ single cell RNAseq and TREM2-deficient mice to define how TREM2 regulates gene expression and severity of lung injury after neonatal hyperoxia exposure. In Aim 2 we will apply novel approaches using myeloid p53-deficient mice exposed to neonatal hyperoxia and interrogate epigenomic modifications using ATACseq and ChIPseq to identify the regulatory mechanisms by which TREM2 directs a pathogenic immune response on a transcriptional level. Lastly, to establish proof-of-principle for the translational potential of therapeutic targeting of TREM2 we will test a TREM2 blocking antibody in vivo and assess recovery from hyperoxia in room air (Aim 3). Further investigations of the conservation of gene regulatory pathways between mice and humans will provide a sound rationale to use these gene pathways to develop targeted therapies. This project will identify unique gene regulatory networks of lung myeloid cells that support a regenerative immune response in the developing lung. These findings will elucidate novel pathways of neonatal lung resilience after hyperoxia, which will inform the development of more targeted management of multifactorial BPD.