Novel regulators, components and function of endothelial diaphragms

内皮隔膜是与血管内皮亚细胞结构相关的蛋白质屏障， 作为窗孔，跨内皮通道（TEC），小窝和囊泡空泡细胞器参与 血管通透性和免疫反应。窗孔是血管内皮细胞上的圆形穿细胞孔 细胞在维持基础渗透性中起关键作用。人类和小鼠的最新数据 证明窗孔及其横膈膜在维持正常内皮细胞中起着关键作用， 屏障功能、血液稳态和最终存活。我们的小组证明质膜 囊泡相关蛋白（PLVAP或PV 1）对隔膜组装至关重要， 小鼠和人由于多种血管缺陷导致异常窗孔和围产期死亡。r1是 在免疫反应中也至关重要，目前正在开发基于PV 1生物学的治疗策略， 心肌梗塞、免疫性疾病和癌症。虽然人们对隔膜和 在临床上，我们对窗孔组件的理解存在重大知识差距， 调节途径的开窗和隔膜形态发生，在这个建议。批判性 对于这个提议，PV 1是隔膜的唯一已知标记，我们将在我们的 调节膈肌形态发生研究。根据我们的初步数据和文献，我们的中心 假设是多种信号通路以血管床特异性方式协同作用于隔膜， 窗孔形成具体地，生长因子和层粘连蛋白结合整联蛋白受体之间的串扰是由细胞因子和细胞因子之间的相互作用引起的。 对于PV 1表达和窗孔及隔膜形态发生至关重要。这个假设是基于我们的关键 新的观察结果包括：1）不同血管床窗的节段和空间控制不同; 2)基因表达筛选参与PV 1调节的因子，鉴定出SCF、FGF-5、VEGF-A和 特异性层粘连蛋白通过其各自的c-KIT、FGFR 1、VEGFR 2和ITGB 1受体进行信号传导， PV 1以ERK 1/2依赖的方式表达;和3）层粘连蛋白与SCF、FGF-5和VEGF-1的组合， A导致PV 1的稳健表达和从头窗孔形成。 功能验证的内皮细胞培养系统和基因工程动物的组合 使用功能丧失、功能获得和重建方法的模型。我们的目标将定义角色， 新鉴定的生长因子和层粘连蛋白及其整合素受体的下游信号传导途径 调节PV 1表达和窗孔形态发生。我们在关键和关键方面都处于独特的地位， 有必要的专业知识来完成这项工作。这些研究将确定调控因素和途径 控制复杂和生理相关的细胞结构的组装， 这是目前缺乏的洞察力。

Endothelial diaphragms are protein barriers associated with vascular endothelial subcellular structures, such as fenestrae, transendothelial channels (TEC), caveolae and vesiculo-vacuolar organelles implicated in vascular permeability and immune response. Fenestrae are circular transcellular pores in vascular endothelial cells playing critical roles in the maintenance of basal permeability. Recent data in humans and mice demonstrate that fenestrae and their diaphragms play critical roles in the maintenance of normal endothelial barrier function, blood homeostasis and ultimately survival. Our group demonstrated that Plasmalemma Vesicle Associated Protein (PLVAP or PV1) is critical for diaphragm assembly, and that absence of PV1 in mice and humans causes abnormal fenestrae and perinatal lethality due to multiple vascular defects. PV1 is also critical in the immune response, and therapeutic strategies based on PV1 biology are being developed for myocardial infarction, immune diseases and cancer. While there is emerging interest in diaphragms and fenestrae in the clinic, there is a significant knowledge gap in our understanding of the components and regulatory pathways governing fenestrae and diaphragm morphogenesis, addressed in this proposal. Critically for this proposal, PV1 is the only known marker for diaphragms, and we will exploit this property in our investigation of regulation diaphragm morphogenesis. Based on our preliminary data and literature, our central hypothesis is that multiple signaling pathways synergize in vascular bed specific manner for diaphragm and fenestrae formation. Specifically, crosstalk between growth factors and laminin binding integrin receptors are critical for PV1 expression and fenestrae and diaphragm morphogenesis. This hypothesis is based on our key new observations including: 1) differential segmental and spatial control of fenestrae in different vascular beds; 2) Gene expression screens for factors involved in PV1 regulation, identified SCF, FGF-5, VEGF-A and specific laminins signaling via their respective c-KIT, FGFR1, VEGFR2, and ITGB1 receptors as necessary for PV1 expression in ERK1/2 dependent manner; and 3) the combination of laminin with SCF, FGF-5 and VEGF- A results in robust PV1 expression and de novo fenestrae formation We will test our hypothesis using a combination of functionally validated endothelial cell culture systems and genetically engineered animal models using loss of function, gain of function and reconstitution approaches. Our Aims will define the role and downstream signaling pathways of newly identified growth factors and laminins and their integrin receptors regulating PV1 expression and fenestrae morphogenesis. We are uniquely positioned both in terms of key and necessary expertise to complete this work. These investigations will define regulatory factors and pathways controlling the assembly for an intricate and physiologically relevant cellular structure, providing valuable insight that is currently lacking.