Regulation of mural cells during pulmonary capillary formation

项目摘要：肺泡毛细血管结构和功能紊乱 肺气肿。恢复肺微血管系统也是一项重要的治疗目标 间质纤维化等引起肺动脉高压的原因。实现这一目标的关键一步是 确定在肺泡间隔形成过程中调节毛细血管扩张和成熟的因素。 假设：肺泡毛细血管网络的形成和扩张需要 内皮细胞、周细胞和肺成纤维细胞(LF)。在继发间隔形成过程中，PDGF介导的 信号转导周细胞和MF以确保(A)这些细胞群体的扩张和维持，(B) 迁移和建立与内皮的细胞间联系，以及(C)现有的 内皮管允许毛细血管表面积的快速扩张。具体目标1：(A)证明 随着毛细血管网络的形成，成纤维细胞和周细胞在内皮细胞上空间聚集。 和(B)研究PDGF介导的信号如何通过以下方式调节壁鞘的形成 小鼠的周细胞和肌成纤维细胞。具体目标2：研究PDGF-A和PDGF-A的细胞机制 PDGF-B通过促进细胞迁移和细胞的形成，在体外促进壁鞘的形成。 细胞沿内皮管接触。转基因小鼠将用于识别和定位肺泡 (A)表达PDGF受体-α(PDGF-R)或(B)的细胞具有周细胞的特征。激光 扫描共聚焦显微镜(LSCM)和体视学将被用来分析LF和周细胞的进入和 它们与网状结构中的肺泡内皮细胞相关。这些研究将确定是否有一个 毛细血管内皮细胞与周围LF和Lf之间的距离随时间进行性减小 周细胞。研究还将研究如何扰乱LF和周细胞中的PDGF信号通路(A)。 毛细血管网和(B)周细胞和LF的增殖和寿命。重要的信号通路， 它由PDGFs启动，由Abelson激酶和rac1介导，改变周细胞或LF的增殖 并对细胞凋亡进行检测。第二个目标，我们将研究PDGF-A和PDGF-B如何引导 培养中内皮细胞、周膜细胞和周细胞的迁移和联合。内皮细胞和壁细胞 在毛细管壁中聚集。为了了解这些细胞是如何混合的，细胞表面的黏附分子 比较壁细胞迁移到壁细胞与内皮基底膜结合时的情况。 调节细胞间相互作用的分子，包括胶凝素和钙粘附素，将作为细胞进行研究。 从迁徙状态过渡到固着状态，并形成附着和紧密连接。详细的延时 微观研究将揭示层粘连蛋白和整合素如何促进PDGF-A或PDGF-B刺激的血管迁移 成纤维细胞和周细胞。这些研究将提供有关非萌芽血管生成的新信息。 (NSA)在肺中。对美国国家安全局的更好理解可能会确定在 涉及肾脏和脑等其他微血管床的疾病的发病机制和修复。 微血管病变是糖尿病、中风和慢性肾功能不全的核心，这些疾病正在变得越来越多。 在退伍军人中很流行。。对退伍军人医疗保健的潜在影响：这些研究可能会促进 新疗法的开发改善了治疗结果并降低了治疗成本 肺气肿和血管疾病在退伍军人中很常见。

PROJECT SUMMARY: The structure and function of alveolar capillaries are deranged in pulmonary emphysema. Restoration of the pulmonary microvasculature is also an important therapeutic goal for interstitial fibrosis and other causes of pulmonary hypertension. A critical step towards achieving this goal is to identify factors which regulate capillary expansion and maturation during alveolar septal formation. Hypothesis: Formation and expansion of the alveolar capillary network requires cooperation among endothelial cells, pericytes, and lung fibroblasts (LF). During secondary septal formation, PDGF-mediated signaling directs pericytes and MF to ensure (a) expansion and maintenance of these cell populations, (b) migration and establishment of intercellular contacts with the endothelium, and (c) sub-division of the existing endothelial tubes to allow rapid expansion of capillary surface area. Specific Aim 1: To (a) demonstrate that fibroblasts and pericytes spatially converge on the endothelium as the capillary meshwork forms during septation and (b) investigate how PDGF-mediated signaling regulates formation of the mural sheath by pericytes and myofibroblasts in mice. Specific Aim 2: Examine cellular mechanisms whereby PDGF-A and PDGF-B promote formation of the mural sheath in vitro by enhancing cell migration and the formation of cell- cell contacts along endothelial tubes. Genetically modified mice will be used to identify and localize alveolar cells which (a) express PDGF receptor-alpha (PDGF-R¿) or (b) have characteristics of pericytes. Laser scanning confocal microscopy (LSCM) and stereology will be used to analyze ingress of LF and pericytes and their association with alveolar endothelial cells in the meshwork. These studies will ascertain if there is a temporally progressive decrease in the distance between the capillary endothelium and surrounding LF and pericytes. Studies will also examine how disrupting PDGF-signaling pathways in LF and pericytes alters (a) the capillary meshwork and (b) pericyte and LF proliferation and longevity. Important signaling pathways, which are initiated by PDGFs, are mediated by Abelson kinase and Rac1, and alter pericyte or LF proliferation and apoptosis will be examined. The second aim we will examine how PDGF-A and PDGF-B direct the migration and association of endothelial cells, LF, and pericytes in culture. Endothelial and mural cells coalesce in the capillary wall. To learn how these cells intermingle, cell surface adhesion molecules will be compared when mural cells migrate to when the mural coalesce with the endothelial basement membrane. Molecules, including nectins and cadherins, which regulate cell-cell interactions will be investigated as cells transition from a migratory to a sessile state, and form adherens and tight junctions. Detailed time-lapse microscopic studies will reveal how laminin and integrins promote PDGF-A or PDGF-B-stimulated migration of fibroblasts and pericytes. These studies will provide novel information about non-sprouting angiogenesis (NSA) in the lung. A better understanding of NSA may identify factors that are also important in the pathogenesis and repair of diseases involving other microvascular beds such as the kidneys and brain. Microangiopathies are central to diabetes, stroke, and chronic renal insufficiency, which are becoming more prevalent among veterans. . Potential impact for veterans' health care: These studies may foster the development of new therapies resulting in improved outcomes and lower costs for treating pulmonary emphysema and vascular diseases, which is are common among veterans.