Developmental Heterogeneity of Pulmonary Endothelial Phenotype at Single Cell Resolution

单细胞分辨率肺内皮表型的发育异质性

• 批准号: 10211048
• 负责人: Cristina Maria Alvira
• 金额: $ 70.82万
• 依托单位: STANFORD UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-09-15 至 2025-07-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10211048
• 关键词: APLN gene; ATAC-seq; Adult; Affect; Air; Air Sacs; Alveolar; Alveolar Cell Type I; Appearance; Area; Automobile Driving; Birth; Blood Vessels; Bronchopulmonary Dysplasia; Cell Proliferation; Cells; Chronic; Complication; Cues; Data; Data Set; Development; Disease; Distal; Endothelial Cells; Endothelium; Experimental Models; Gases; Gene Expression; Gene Expression Profile; Genes; Genetic Transcription; Growth; Heterogeneity; Hyperoxia; Image; Impairment; In Vitro; Infant; KITLG gene; Knockout Mice; Knowledge; Life; Ligands; Lung; Mediating; Microcirculation; Molecular; Mus; Natural regeneration; Neonatal Hyperoxic Injury; Organ; Pathway interactions; Perinatal; Phase; Phenotype; Population; Premature Birth; Process; Resolution; Role; Signal Transduction; Stimulus; Surface; Testing; Time; Transgenic Organisms; Translating; Work; angiogenesis; blood vessel development; in vivo; loss of function; lung development; lung injury; migration; mouse model; novel; novel strategies; novel therapeutic intervention; paternal imprint; postnatal; postnatal development; premature; progenitor; rapid growth; receptor; receptor expression; response; self-renewal; single-cell RNA sequencing; stem; stem cells; targeted treatment; transcription factor; transcriptomics; virtual

Postnatal lung growth during alveolarization markedly increases gas exchange surface area. Rapid growth of the pulmonary vasculature during early alveolarization drives distal lung growth. As alveolarization slows, the vasculature transitions from a phase of angiogenic growth to quiescence, however the molecular mechanisms regulating this transition remain poorly defined. This gap in knowledge confounds efforts to develop targeted therapies to treat diseases of dysregulated angiogenesis and impaired alveolarization, including bronchopulmonary dysplasia, the most common complication of preterm birth. We recently employed single cell transcriptomics to define endothelial cell (EC) diversity during postnatal lung development and to identify novel mechanisms regulating pulmonary angiogenesis and quiescence. Our preliminary data identified a tremendous increase in EC diversity after birth, marked by the appearance of numerous transcriptionally distinct clusters. A highly proliferative EC cluster is abundant before birth, virtually disappears just after birth, but peaks again at early alveolarization, a time of exponential pulmonary angiogenesis. The microvascular EC (MEC) broadly separated into Car4 expressing (Car4+) and Car4- MEC. In contrast with gradual changes in gene expression in the Car4+ MEC over time, gene expression changed dramatically in the Car4- MEC, with separation of this population into two transcriptionally distinct clusters of “early” (P1-P7) and “late” (P21) Car4- MEC. High expression of the paternally imprinted gene-3 (Peg3), a gene expressed by self-renewing progenitor cells, distinguished the “early” from the “late” Car4- MEC. Peg3 also enhances NFkB signaling, a pathway we previously identified as essential for pulmonary angiogenesis during early alveolarization. Of note, the expression of receptor-ligand pairs suggested that cross-talk stemming from the Car4+ MEC may promote pro-proliferative and pro-angiogenic signaling in the Car4- MEC. Taken together, our data suggest the overall hypothesis that the early Car4- MEC represent a specialized, highly proliferative and angiogenic EC population required for the rapid growth of the pulmonary vasculature during early alveolarization, which will be tested through three specific aims. Aim 1 will utilize transgenic and cell-specific knock out mice, advanced imaging, and loss of function studies in primary EC to probe the role of Peg3 in promoting proliferation, angiogenesis and NFkB activation in Car4- MEC. Aim 2 will use FACS sorted Car4+ and Car4- MEC and a novel mouse model permitting targeting of Car4+ MEC to test if interaction between these two distinct MEC promotes postnatal angiogenesis. Finally, Aim 3 will employ computational ligand-receptor analysis, ATAC-Seq, and EC-specific knock out mice to determine if chronic hyperoxia impairs angiogenesis by impairing Car4- MEC proliferation, Peg3-mediated self-renewal and Car4+ and Car4- MEC cross-talk. The successful completion of these studies will provide a deep view of pulmonary vascular development at single cell resolution, and identify new pathways that may be translated into novel strategies to enhance lung growth and regeneration in diseases marked by impaired pulmonary angiogenesis.

出生后肺泡化过程中的肺部生长显着增加了气体交换表面积。迅速的 早期肺泡化期间肺血管系统的生长驱动远端肺生长。由于肺泡化 减慢，脉管系统从血管生成阶段过渡到静止阶段，但是分子 调节这一转变的机制仍然不明确。这种知识差距阻碍了发展努力 治疗血管生成失调和肺泡化受损疾病的靶向疗法，包括 支气管肺发育不良是早产最常见的并发症。我们最近采用了单细胞 转录组学可定义出生后肺发育过程中的内皮细胞 (EC) 多样性并识别新的 调节肺血管生成和静止的机制。我们的初步数据表明， 出生后 EC 多样性增加，其特征是出现许多转录上不同的簇。一个 高度增殖的 EC 簇在出生前大量存在，出生后几乎消失，但在出生时再次达到峰值 早期肺泡化，肺血管指数呈指数增长的时期。微血管 EC (MEC) 广泛 分为Car4表达(Car4+)和Car4-MEC。与基因表达的逐渐变化相反 随着时间的推移，在 Car4+ MEC 中，Car4- MEC 中的基因表达发生了巨大变化，并且与此分离 群体分为两个转录上不同的簇：“早期”（P1-P7）和“晚期”（P21）Car4-MEC。高的 父系印记基因 3 (Peg3) 的表达，这是一种由自我更新祖细胞表达的基因， 区分“早期”和“晚期”Car4-MEC。 Peg3 还增强 NFkB 信号传导，这是我们研究的一个途径 先前被认为对于早期肺泡化过程中的肺血管生成至关重要。值得注意的是，表达式 受体-配体对的研究表明，Car4+ MEC 产生的串扰可能促进促增殖 Car4-MEC 中的促血管生成信号传导。综上所述，我们的数据表明了总体假设： 早期 Car4-MEC 代表了快速增殖所需的专门的、高度增殖和血管生成的 EC 群体。 早期肺泡化过程中肺血管系统的生长，将通过三个特定目标进行测试。 目标 1 将利用转基因和细胞特异性敲除小鼠、先进成像和初级功能丧失研究 EC 探讨 Peg3 在促进 Car4-MEC 增殖、血管生成和 NFkB 激活中的作用。目标2将 使用 FACS 分选的 Car4+ 和 Car4- MEC 以及允许靶向 Car4+ MEC 的新型小鼠模型来测试是否 这两种不同的 MEC 之间的相互作用促进出生后血管生成。最后，目标 3 将采用 计算配体-受体分析、ATAC-Seq 和 EC 特异性敲除小鼠以确定慢性 高氧通过损害 Car4-MEC 增殖、Peg3 介导的自我更新和 Car4+ 来损害血管生成 和 Car4-MEC 串扰。这些研究的成功完成将为肺部提供深入的了解。 以单细胞分辨率观察血管发育，并确定可转化为新途径的新途径 在以肺血管生成受损为特征的疾病中增强肺生长和再生的策略。