新喋呤调控内皮细胞miR-132诱导斑块新生血管增生的作用及机制研究

The proliferation of adventitial vasa vasorum and intraplaque neovascularization are thought to play key roles in initiation and development of atherosclerosis. The serum Npt level is recognized as an important biomarker which provides prognostic and predictive information on the patients with atherosclerosis. Our clinical study has demonstrated that neopterin (Npt) is an important predictor of neovascularization within the culprit lesion in patients with coronary artery disease. However, it is not clear that whether Npt contributes to the process of angiogenesis and progression of atherosclerotic plaques. Our previous experimental data indicated that Npt can induce the proliferation and tube formation of human coronary artery endothelial cell (HCAEC) in vitro and up-regulate the expression of miR-132 in HCAEC. MicroRNA-132 is demonstrated as an angiogenic "switch" by inhibiting p120RasGAP in endothelium cell. Therefore, we postulated that miR-132 up-regulated by Npt leads to HCAEC proliferation, migration and tube formation, which is a novel mechanism for angiogenesis in atherosclerosis. In this study, we will employ a wide range of molecular biological techniques including gene transfection, western blotting and quantitative RT-PCR. In addition, multiple advanced imaging modalities including optical coherence tomography, virtual-histology and acoustic contrast will be performed to investigate the effect of Npt on angiogenesis within atherosclerosis and to disclose the mechanism of the miR-132 up-expression by Npt. Our results may provide a new therapeutic target of the pharmacological intervention to atherosclerosis.

动脉粥样硬化(AS)外膜及斑块内新生血管增生在AS发展中具有重要作用。新喋呤(Npt)是AS病情评估的重要标记物，我们课题组也证实了患者血清Npt水平是冠状动脉斑块内新生血管增生的独立预测因素。然而，Npt是否能作为活性物质促进AS新生血管增生从而加速AS进展尚不清楚。本课题组首次发现Npt促进人冠状动脉内皮细胞(HCAEC)增殖及管腔形成，并上调miR-132。miR-132作为血管新生的"开关", 通过抑制p120RasGAP促进血管新生。因此, 我们推测"Npt上调miR-132促进HCAEC增殖、迁移及管腔形成"是AS外膜及斑块内新生血管增生的新机制。本课题利用基因转染、Western blot及RT-PCR等技术并结合光学相干成像、虚拟组织学及声学造影等先进影像模式，从细胞到整体水平研究Npt对AS新生血管的作用及Npt调控miR-132的机制,其结果有望为AS防治提供新靶点。

动脉粥样硬化是当今世界病人死亡的主要病因。斑块内新生血管及外膜滋养血管的增生与斑块稳定性和稳定斑块向易损斑块转变有明显关系，是新的抗动脉粥样硬化靶点。光学相干断层扫描技术是能准确评估斑块特征的血管内诊断技术，具有高分辨率。我们执行系列的研究分析新生血管与动脉粥样硬化的关系,找出易损斑块人体内的关键形态特征。依托于该课题，我们在新生血管对AS的作用及调控机制方面取得多个成果。本课题利用基因转染、Western blot及RT-PCR等技术并结合光学相干成像、虚拟组织学及声学造影等先进影像模式，从细胞到整体水平揭示新生血管与AS关系，Npt对AS新生血管的作用及Npt调控miR-132的机制。研究结果发现Npt显著地促进了HCAEC增殖，管腔形成能力，迁移能力。体内研究按期完成，建立动物AS模型，按照实验设计分组进行干预、影像检查及血液指标监测。已结发表多篇SCI论文。我们既往主要成果如下：(1)新生血管在罪犯病变中的作用与非罪犯病变中的作用明显不同，提示新生血管对动脉粥样硬化稳定性的影响在不同阶段作用不一样。新生血管增殖与动脉粥样硬化斑块进展的有重要关系，而且他汀有独立于降血脂的抗新生血管及抗动脉粥样硬化效果。 (2)支架内新生动脉粥样硬化及新生血管易于在支架两端发生，而且支架内新生动脉粥样硬化及新生血管存在明显的空间分布一致性及发生率明显相关。现有抗动脉粥样硬化治疗之下，冠心病患者很多斑块在一年的随访中未出现明显的斑块进展。部分进展的病变，有缓慢进展及阶段式快速进展两种模式。易损斑块、新生微血管及正性重构是阶段式快速斑块进展的独立预测因子。 (3) 新喋呤(Npt)是AS病情评估的重要标记物，而且在斑块进展中也具有重要的作用。Npt通过诱导HCAEC内ROS生成激活MAPKs通路促进CREB磷酸化，从而上调miR-132表达，促进HCAEC增殖、迁移及管腔形成生成。本课题将在细胞-整体水平验证我们前期假设，实验结果具有重要的理论意义和应用价值。为抗AS新生血管增生及AS进展提供一种新思路和新靶点。