类胰蛋白酶在ApoE-/-小鼠动脉粥样硬化斑块内出血中的作用及机制研究

项目名称： 类胰蛋白酶在ApoE-/-小鼠动脉粥样硬化斑块内出血中的作用及机制研究

项目编号： No.30871021

项目类型： 面上项目

立项/批准年度： 2009

项目学科： 金属学与金属工艺

项目作者： 殷莲华

作者单位： 复旦大学

项目金额： 30万元

中文摘要： 肥大细胞类胰蛋白酶（Tryptase）在动脉粥样硬化斑块发生发展中的作用日益受到重视。本课题探讨类胰蛋白酶与斑块内出血的关系。首先ApoE-/-小鼠行颈总动脉套环术，建立斑块内出血模型，尾静脉注射过或干扰表达Tryptase的慢病毒载体。结果显示，未套环侧：Tryptase显著促进颈总动脉斑块面积；套环侧：过表达Tryptase明显促进斑块内出血，出血率及程度远大于干扰组；免疫组化结果显示Tryptase促进斑块血管新生；过表达Tryptase组斑块内CD31表达升高，凝血纤溶因子PAI降低，tPA升高。其次，Tryptase促进bEnd.3细胞增殖、迁移、管腔形成能力，抑制bEnd.3细胞PAI表达，上调tPA表达。此外,Tryptase 通过PAR-2/LXRαXRα30446;标基因信号通路抑制LXRα27963;化，从而促进巨噬细胞泡沫化。综上，类胰蛋白酶促进动脉粥样硬化斑块内血管新生及斑块内出血，其机制可能与调控凝血纤溶因子有关。本研究为动脉粥样硬化易损斑块的防治提供了实验依据和新的靶点。

中文关键词： 类胰蛋白酶；动脉粥样硬化；斑块内出血；血管新生；ApoE-/- 小鼠

英文摘要： Tryptase, the most abundant mast cell (MC) granule protein, plays an important role in atherosclerosis plaque development. We hypothesize that tryptase participates directly in atherosclerosis plaque haemorrhage. Firstly,atherosclerosis plaque haemorrhage models in ApoE-/- mice were constructed. After a cuffing-cervical artery operation, the mice were randomly divided into 6 groups. Hematoxylin and eosin(HE) staining showed that the cervical artery plaque area on the uncuff-side was much larger in the tryptase overexpression group compared to the other groups. On the cuff-side , tryptase promotes plaque haemorrhage distinctively because 50% of the mice in the tryptase overexpression group had plaque haemorrhage, while only 10% in the siRNA group did.The immunohistochemistry of the cervical artery plaque showed that plasminogen activator inhibitor-1 (PAI-1) expression in the tryptase overexpression group was the lowest while tissue plasminogen activator (tPA) and CD31 was the highest, which was completely contrary to the siRNA group. Tryptase promoted bEnd.3 cell growth, migration and capillary-like tube formation, which suggests that tryptase can promote microvessel angiogenesis. PAI-1 expression was inhibited, while tPA expression was increased by tryptase in bEnd.3 cells.In addition,our data clarified the PAR-2 expression of human macrophages and suggested that tryptase might promote lipid accumulation in macrophages and foam cell formation by suppressing LXRαctivation via PAR-2/LXRαXRαarget genes signaling pathway. Our in vivo and in vitro studies suggest that trypase can promote atherosclerotic plaque haemorrhage by promoting angiogenesis and regulating the balance of PAI-1 and tPA. Thus, inhibiting tryptase expression in MCs may be a new therapeutic strategy for atherosclerosis.

英文关键词： tryptase;atherosclerosis;intraplaque hemorrhage;angiogenesis;apoE-/- mice