Regulation of mural cells during pulmonary capillary formation

肺毛细血管形成过程中壁细胞的调节

• 批准号: 8195607
• 负责人: STEPHEN E MCGOWAN
• 金额: --
• 依托单位: IOWA CITY VA MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-10-01 至 2013-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8195607
• 关键词: Address; Adherens Junction; Adult; Alveolar; Alveolar Cell; Animal Model; Apoptosis; Area; Attenuated; Basement membrane; Birth; Blood Cells; Blood Vessels; Blood capillaries; Blood flow; Brain; Bronchopulmonary Dysplasia; Cadherins; Cell Adhesion Molecules; Cell Communication; Cell Maintenance; Cell surface; Cells; Characteristics; Chronic Kidney Insufficiency; Chronic Obstructive Airway Disease; Defect; Development; Diabetes Mellitus; Diffusion; Disease; Disease Progression; Endothelial Cells; Endothelium; Ensure; Epithelial Cells; Extravasation; Fibroblasts; Fibrosis; Filtration; Fostering; Gap Junctions; Gases; Goals; Growth; Health Care Costs; Healthcare; Hospitalization; Human; In Vitro; Integrins; Kidney; LacZ Genes; Laminin; Laser Scanning Confocal Microscopy; Learning; Liver; Longevity; Lung; Mediating; Mesenchymal; Microcirculatory Bed; Microscopic; Molecular; Mus; Myofibroblast; Newborn Infant; Nuclear; Organ; Outcome; PDGF Signaling Pathway; Pathogenesis; Pericytes; Permeability; Phosphotransferases; Plasma; Platelet-Derived Growth Factor; Platelet-Derived Growth Factor alpha Receptor; Population; Pulmonary Circulation; Pulmonary Emphysema; Pulmonary Gas Exchange; Pulmonary Hypertension; Regulation; Signal Pathway; Signal Transduction; Smooth Muscle Myocytes; Stroke; Structure; Supporting Cell; Surface; Symptoms; Therapeutic; Tight Junctions; Time; Tube; Vascular Diseases; Vascular Endothelial Growth Factors; Veterans; angiogenesis; arteriole; capillary; capillary bed; cell motility; cost; improved; interstitial; intimate behavior; mesangial cell; migration; mixed cell culture; nectin; neutrophil; novel; platelet-derived growth factor A; prevent; public health relevance; repaired; restoration; smoking prevalence; stellate cell; tumor; venule

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.

项目摘要：肺泡毛细血管的结构和功能紊乱 肺气肿的恢复也是一个重要的治疗目标。 间质纤维化和肺动脉高压的其他原因是实现这一目标的关键一步。 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各器官之间的合作 内皮细胞、周细胞和肺成纤维细胞 (LF) 在次级间隔形成过程中，PDGF 介导。 信号传导指导周细胞和 MF 以确保 (a) 这些细胞群的扩增和维持，(b) 迁移以及与内皮细胞间接触的建立，以及（c）现有细胞的细分 内皮管允许毛细血管表面积快速扩张。 具体目标 1： (a) 证明 随着毛细血管网的形成，成纤维细胞和周细胞在空间上聚集在内皮上 (b) 研究 PDGF 介导的信号如何通过调节壁鞘的形成 具体目标 2：检查 PDGF-A 和肌成纤维细胞的细胞机制。 PDGF-B 通过增强细胞迁移和细胞形成来促进壁鞘的形成。 沿内皮管的细胞接触将用于识别和定位肺泡。 (a) 表达 PDGF 受体-α (PDGF-R¿) 或 (b) 的细胞具有周细胞激光的特征。 扫描共焦显微镜 (LSCM) 和体视学将用于分析 LF 和周细胞的进入， 它们与网络中的肺泡内皮细胞的关联。这些研究将确定是否存在关联。 毛细血管内皮与周围 LF 之间的距离暂时逐渐减小 研究还将探讨扰乱 LF 和周细胞中的 PDGF 信号通路如何改变 (a) 毛细血管网和 (b) 周细胞和 LF 增殖和寿命。 由 PDGF 启动，由 Abelson 激酶和 Rac1 介导，并改变周细胞或 LF 增殖 第二个目标是研究 PDGF-A 和 PDGF-B 如何指导细胞凋亡。 培养物中内皮细胞、LF 和周细胞的迁移和结合。 为了了解这些细胞如何混合，细胞表面粘附分子将在毛细血管壁中结合。 比较壁细胞迁移时与壁细胞与内皮基底膜融合时的情况。 调节细胞间相互作用的分子，包括连接蛋白和钙粘蛋白，将作为细胞进行研究 从迁移状态转变为固着状态，并形成粘附和紧密连接。 显微镜研究将揭示层粘连蛋白和整合素如何促进 PDGF-A 或 PDGF-B 刺激的迁移 这些研究将提供有关非萌芽血管生成的新信息。 更好地了解 NSA 可能会识别出在肺部也很重要的因素。 涉及肾脏和大脑等其他微血管床的疾病的发病机制和修复。 微血管病是糖尿病、中风和慢性肾功能不全的核心，这些疾病正变得越来越严重。 对退伍军人医疗保健的潜在影响：这些研究可能会促进。 开发新疗法可改善结果并降低治疗肺结核的成本 肺气肿和血管疾病在退伍军人中很常见。