Adenosine Receptors and Atherogenesis

摘要 腺苷结合腺苷酸环化酶刺激性（A2型）腺苷受体（AR）诱导冠状动脉粥样硬化 血管舒张，抑制人主动脉血管平滑肌细胞增殖，并影响动脉壁基质 所有这些都是动脉粥样硬化/再狭窄的重要组成部分。低亲和力的作用 在我们的研究之前，还没有研究过A2 bAR在体内调节血管病理学方面的作用。以进一步解决 为此，我们建立了第一个A2 bAR敲除（KO）/报告基因敲入小鼠模型，并显示了报道的 基因表达主要在VSMC和巨噬细胞中，与对照的内源性谱一致 小鼠促炎细胞因子的增加，如肿瘤坏死因子-<$（TNF-<$），是潜在的 观察到这些A2 bAR KO小鼠血管系统中白细胞粘附上调的机制， 与年龄、性别和品系匹配的对照小鼠相比。另一方面，A2 bAR基因受体， 它本身是由TNF-α诱导的，表明存在一个调节环。A2 bAR KO小鼠显示出更大的病变形成， 导丝引起的股动脉损伤。这与CXCR 4的上调有关， 已知通过与其配体相互作用促进祖细胞和炎性细胞向血管的动员 基质细胞衍生因子-1（SDF-1）。此外，骨髓（BM）移植实验表明， 炎症反应和血管损伤的形成受到BM衍生的 A2bAR。基于这些新的发现，我们假设A2 bAR介导的信号转导调节了细胞的增殖。 CXRC 4的表达，因此在血管损伤形成中起重要作用。我们认为， 巨噬细胞A2 bAR通过其控制炎性细胞因子水平的能力，能够显著地 保护自身免受血管病变，与BM移植实验一致。最后， 确定TNF-α对A2 bAR基因调控的机制应该为开发 控制炎症期间血管功能障碍的策略。研究的三个具体目标是 建议：目标1。为了检查BM细胞和/或其信号在介导的作用中的直接参与， A2 bAR在血管损伤和动脉粥样硬化病变形成中的作用，并探讨其相关机制。 关注巨噬细胞A2 bAR的贡献。目标2.为了阐明控制的机制， CXCR 4/SDF-1轴由A2 bAR。目标3：探讨TNF-α激活A2 bAR基因的机制。 原代培养物和体内。总之，我们提出的调查应该揭示新的作用， A2 bARs在血管功能障碍的发病机制中的作用，并且可以将注意力集中在A2 bAR激活作为一种 治疗靶点

ABSTRACT Adenosine binding to adenylyl cyclase stimulatory (A2-type) adenosine receptors (ARs) induces coronary vasodilatation, inhibits human aortic vascular smooth muscle cell proliferation, and affects arterial wall matrix production, all of which are important components of atherosclerosis/restenosis. The role of the low affinity A2bARs in regulating vascular pathology in vivo had not been examined prior to our study. To further address this, we generated the first A2bAR-knockout (KO)/reporter gene-knock-in mouse model and showed reported gene expression primarily in VSMC and macrophages, in accordance with the endogenous profile in control mice. Augmentation of proinflammatory cytokines, such as tumor necrosis factor-¿ (TNF-¿), is the underlying mechanism for an observed upregulation of leukocyte adhesion in the vasculature of these A2bAR KO mice, as compared with age-, sex-, and strain-matched control mice. On the other hand, the A2bAR gene receptor, itself, is induced by TNF-¿, suggesting a regulatory loop. A2bAR KO mice display greater lesion formation after guidewire-induced femoral artery injury. This occurs in association with the upregulation of CXCR4, a protein known to promote mobilization of progenitors and inflammatory cells to the vessel by interaction with its ligand stromal cell-derived factor-1 (SDF-1). Furthermore, bone marrow (BM) transplantation experiments indicate that the inflammatory response and vascular lesion formation are significantly regulated by BM-derived A2bARs. Building upon these novel findings, we hypothesize that A2bAR-mediated signaling regulates the expression of CXRC4 and, hence, plays a vital role in vascular lesion formation. It is our contention that macrophage A2bARs, via their ability to control the level of inflammatory cytokines, are capable of significantly protecting against vascular pathology on their own, consistent with the BM transplantation experiments. Finally, identifying mechanisms of A2bAR gene regulation by TNF-¿ should lead the way for the development of strategies for controlling vascular dysfunction during inflammation. Three specific aims of research are proposed: Aim 1. To examine the direct participation of BM cells and/or their signals in mediating effects of the A2bAR on lesion formation during vascular injury and atherosclerosis, and to study related mechanisms, with a focus on the contribution of macrophage A2bARs. Aim 2. To elucidate the mechanism of control of the CXCR4/SDF-1 axis by the A2bAR. Aim 3. To study the mechanism of A2bAR gene activation by TNF-¿ in primary cultures and in vivo. Taken together, our proposed investigations should shed new light on the role of A2bARs in the pathogenesis of vascular dysfunction, and could focus attention on A2bAR activation as a therapeutic target.