VASCULAR TOPOGRAPHY OF CD39/NTPDASES

该项目致力于肝脏和心脏内的血管异质性。我们将研究这些专门的血管床如何对无处不在的环境信号做出不同的反应，例如生理和病理状态下细胞外核苷酸的通量。内皮细胞（EC）和血管辅助细胞差异表达CD 39家族的外核苷酸酶（例如，NTPD酶1/CD 39、CD 39 L（ike）1/NTPD酶2等）。催化细胞外的核苷酸CD 39/NTPD酶1可以与内皮表面上的某些2型嘌呤能/嘧啶能受体（例如P2 Y2）和整联蛋白受体（例如α-v-β 3）形成功能性大分子复合物;并且还与内皮表面上的潜在的多种细胞内受体形成功能性大分子复合物。 下游组分（例如Ran结合蛋白M; RanBPM）。我们已经表明，NTPD酶水平的扰动具有深刻的血管床特异性病理生理学效应，例如血管通透性和局部促凝反应的改变。在基础条件下，有窗肝窦EC或脑微血管系统的CD 39（或CD 39 L1）表达非常低。相反，心脏EC（和周细胞）通常表现出高水平的NTPD酶。肝、脑或心脏血管损伤后，血管相关NTPD酶显著上调。该过程与肝窦的“毛细血管化”有关。突变小鼠中cd 39的缺失显著增加了肝胰腺血管 在缺血和再灌注损伤后促进出血性死亡。cd 39缺陷小鼠颈动脉闭塞后可观察到广泛出血性中风。此外，当移植到野生型小鼠或大鼠体内时，cd 39-心脏移植物比对照移植物更快地经历排斥反应。具体目标：1）通过绘制NTPD酶、P2 Y2和α-v-β 3在心脏和肝脏微血管中的差异表达来确定大分子复合物的特异性拓扑结构（在基底膜下）。 病理状态）。2)检查与NTPD酶的差异表达和心脏和肝脏血管的表型特性相关的复合物组分之间的功能相互作用。3)NTPD酶在低氧血症和肝脏和心脏血管炎性损伤体内模型中的调节作用的评价。这些研究首次在大分子复合物（而不是单个蛋白质或基因）水平上研究血管多样性，并将提供有关内皮细胞外核苷酸介导的信号传导的新信息。了解微分积分 核苷酸介导的细胞激活在不同的血管床可以提供洞察心血管疾病，中风和肝血管疾病的新的治疗策略。

This project addresses vascular heterogeneity within the liver and heart. We will examine how these specialized vascular beds respond differently to ubiquitous environmental signals, such as fluxes in extracellular nucleotides under both physiological and pathological states. Endothelial cells (EC) and vascular accessory cells differentially express ectonucleotidases of the CD39 family (e.g. NTPDase1/CD39, CD39L(ike)1/NTPDase2 etc.) that catalyze extracellular nucleotides. CD39/NTPDase1 can be shown to form a functional macromolecular complex with certain type-2 purinergic/pyrimidinergic receptors (e.g. P2Y2) and integrin receptors (e.g. alpha-v-beta3) on the endothelial surface; and also with a potential variety of intracellular downstream components (e.g. Ran Binding Protein M; RanBPM). We have shown that perturbations in levels of NTPDases have profound vascular-bed specific pathophysiological effects e.g. alterations in vascular permeability and local procoagulant responses. Expression of CD39 (or CD39L1) by fenestrated hepatic sinusoidal EC or cerebral microvasculature is very low under basal conditions. In contrast, cardiac EC(and pericytes) typically exhibit high levels of NTPDases. Following liver, brain or cardiac vascular injury there is dramatic upregulation of vascular-associated NTPDases. This process is associated with "capillarization" of the hepatic sinusoids. Deletion of cd39 in mutant mice dramatically increases hepatosplanchnic vascular permeability that promotes hemorrhagic death following ischemia and reperfusion injury. Extensive hemorrhagic stroke is observed following carotid occlusion in cd39-deficient mice. Further, cd39-cardiac transplants undergo rejection more rapidly than control grafts when transplanted into wild type mice or into rats in vivo. Specific Aims: 1) Determine the specific topology of the macromolecular complex by mapping out the differential expression of NTPDases, P2Y2 and alpha-v-beta3 in the cardiac and hepatic microvasculatures (under basal and pathological conditions). 2) Examine functional interactions between components of the complex that correlate with the differential expression of NTPDases and phenotypic properties of the cardiac and hepatic vasculatures. 3) Evaluation of regulatory role of NTPDases in vivo models of hypoxemia and inflammatory injury to hepatic and cardiac vasculatures. These studies are the first to study vascular diversity at the level of a macromolecular complex (rather than a single protein or gene) and will provide new information regarding extracellular nucleotide-mediated signaling in the endothelium. Understanding the differential integration of nucleotide-mediated cellular activation in different vascular beds could provide insights into novel therapeutic strategies for cardiovascular disease, stroke and hepatic vascular disorders.