PDGFR-beta+ stromal cells as critical regulators of immune response to tissue injury

 描述（由申请方提供）：周细胞是一种研究不足的血管周围基质细胞群，与大多数组织（包括肺）中的微血管系统相关。本授权申请中的初步数据显示：1）FoxD 1衍生的PDGFR+假定周细胞表达多种MyD 88依赖性Toll样受体，2）暴露于从正常小鼠和肺损伤小鼠收集的支气管肺泡灌洗液（BAL）后，PDGFR+细胞表达炎性趋化因子并通过MyD 88依赖性信号转导下调Angpt 1，3）PDGFR β +细胞在肺损伤过程中具有相似的体内转录应答。这些数据支持本申请的中心假设，即FoxD 1衍生的PDGFR+细胞作为间质哨兵发挥作用，其检测并响应于肺泡破裂后释放到肺泡中的组成性肺泡腔分子。活化的PDGFR β +细胞通过促进微血管通透性和白细胞募集来应答。为了验证这一假设，提出了三个目标。第一个目的是评价肺泡隔室分子激活PDGFR β +细胞的机制。将鉴定BAL液激活PDGFR+细胞所需的受体。将使用称为正交色谱法的新型无偏倚方法鉴定BAL液中PDGFR+细胞激活“危险信号”。将评价不同PDGFR+亚群的作用。第二个目标将使用独特的3D微流体装置与原代内皮细胞共培养，以检查PDGFRs+细胞在炎症期间调节内皮功能中的作用，重点关注Angpt 1-Tie 2信号传导。将测量内皮屏障完整性、白细胞粘附和血小板粘附。第三个目标将确定在肺损伤过程中周细胞激活的体内功能后果。肺损伤过程中PDGFR+细胞的“翻译转录组”将用于鉴定PDGFR+细胞的关键信号网络和新的功能反应。肺损伤将在正常小鼠和具有PDGFR β限制性MyD 88缺失的小鼠之间进行比较。该项目将测试PDGFR+细胞是未识别的“间质哨兵细胞”的假设，其随时准备检测和响应显著的肺泡上皮损伤和屏障完整性丧失。急性呼吸窘迫综合征（ARDS）或严重急性肺损伤是危重患者死亡和发病的主要原因，仅在美国每年就有190，000例患者受到影响。尽管经过了数十年的研究，但对ARDS的生物学尚不完全了解，也没有有效的药物治疗方法。该项目代表了该领域的一个新方向，有可能推动新的创新治疗策略的发展。

 DESCRIPTION (provided by applicant): Pericytes are an understudied population of perivascular stromal cell associated with the microvasculature in most tissue, including the lung. Preliminary data in this grant application show that 1) FoxD1-derived, PDGFRß+ putative pericytes express multiple MyD88-dependent Toll-like receptors, 2) following exposure to broncho-alveolar lavage (BAL) fluid collected from normal mice and mice with lung injury, PDGFRß+ cells express inflammatory chemokines and downregulate Angpt1 via MyD88-dependent-signaling, and 3) PDGFRß+ cells have similar transcriptional responses in vivo during lung injury. These data support the central hypothesis of this application that FoxD1-derived, PDGFRß+ cells function as interstitial sentinels, which detect and res-pond to constitutive alveolar luminal molecules that are released into the interstitium following alveolar disruption. Activated PDGFRß+ cells respond by promoting microvascular permeability and leukocyte recruitment. To test this hypothesis, three aims are proposed. The first aim will evaluate mechanism(s) by which PDGFRß+ cells are activated by alveolar compartment molecules. Receptor(s) required for PDGFRß+ cell activation by BAL fluid will be identified. PDGFRß+ cell activating "danger signals" in BAL fluid will be identified, using a novel, unbiased approach termed orthogonal chromatography. The role of different PDGFRß+ subpopulations will be evaluated. The second aim will use a unique 3D-microfluidic device with co-culture of primary endothelial cells to examine the role of PDGFRß+ cells in regulation of endothelial function during inflammation, focusing on Angpt1-Tie2 signaling. Endothelial barrier integrity, leukocyte adhesion, and platelet adhesion will be measured. The third aim will determine in vivo functional consequences of pericyte activation during lung injury. The "translated transcriptome" of PDGFRß+ cells during lung injury will be used to identify critical signaling networks and new functional responses of PDGFRß+ cells. Lung injury will be compared between normal mice and mice with PDGFRß-restricted MyD88 deletion. This project will test the hypothesis that PDGFRß+ cells are unrecognized "interstitial sentinel cells", which stand ready to detect and respond to significant alveolar epithelial injury and loss of barrier integrity. The acute respiratry distress syndrome (ARDS) or severe acute lung injury is a major cause of death and morbidity among critically ill patients, affecting an estimated 190,000 patients annually in the United States alone. Despite decades of research, the biology of ARDS is incompletely understood, and no effective pharmacological treatments exist. This project represents a new direction in the field with the potential to drive the development of novel, innovative therapeutic strategies.