PK2在低密度脂蛋白跨内皮细胞穿胞及动脉粥样硬化中的作用研究

Atherosclerosis is a serious disease with complicated mechanisms involved in lipid metabolism dysfuction in intima. Subendothelial low density lipoprotein(LDL) retention is the initiating process in atherosclerosis. The retention of LDL traffic across endothelial barrier is mainly through transcytosis. Prokineticin 2, a multifunctional-secreted protein, has all kinds of pharmacological effects such as the regulation of cell proliferation and survival in nervous, reproductive and cardiovasular system through activating prokineticins receptors(PKRs). Our previous studies found that Prokineticin 2 inhibited atherogenesis in ApoE-/- mice and the effect of LDL transcytosis and uptake in endothelial cell. But the specific mechanism of Prokineticin 2 mediated the transcytosis effect of LDL in vascular endothelial cells and the direct retention of LDL in intima is unclear. Morphology, immunohistochemistry and molecular biology methods were used in this project to study the effect of Prokineticin 2 to regulate the molecular mechanism of LDL transcytosis via PKRs/caveolin-1 signaling pathway, which can affect the development of atherosclerosis, a screening new targets for the prevention and treatment of atherosclerosis.

动脉粥样硬化(Atherosclerosis, AS)是一种严重危害健康的涉及内膜下脂质代谢紊乱等复杂机制的疾病。低密度脂蛋白（LDL）在血管内膜下的滞留是AS发生的始动作用，其滞留可通过在血管ECs中的穿胞作用而实现，其中穿胞关键蛋白caveolin-1具有重要作用。PK2是一种多功能分泌蛋白，通过其受体PKRs在神经、生殖和心血管等系统中具有调节细胞的增殖和存活等作用。我们研究发现：在ApoE-/-自发AS小鼠实验中，PK2有明显的抗AS作用；进一步研究发现，在血管ECs中，其可抑制LDL的穿胞与摄取作用。但是PK2如何影响LDL在血管ECs中的穿胞并滞留在内膜下从而影响AS的具体机制尚不清楚。本项目拟通过形态学、免疫组织化学和分子生物学等方法深入研究PK2干预PKRs/caveolin-1信号通路来调控LDL穿胞作用从而影响AS的分子机制，为AS疾病的防治提供新的作用靶点。

1.研究了动脉粥样硬化及促动脉粥样硬化形成因素振荡剪切力与PK2的相关性。动物水平发现颈动脉部分结扎（形成振荡剪切力）促进动脉粥样硬化的发生，颈动脉斑块处PK2表达下降；二甲双胍（AMPK的激动剂）有抗动脉粥样硬化的作用，也增加颈动脉PK2的表达。细胞水平发现，游离脂肪酸（PA）减少内皮细胞中PK2的表达，二甲双胍则增加PK2的表达。提示AMPK可能促进PK2分泌发挥抗动脉粥样硬化的作用。2.研究并发现辛伐他汀降低PA诱导的内皮细胞高渗透性，其机制可能与激活TFEB介导的自噬和溶酶体生成通路，抑制Nlrp3炎症小体的激活有关。3.研究并发现脂联素受体激动剂AdipoRon抑制PA诱导心肌细胞的损伤，其机制可能与抑制ROS-NF-ƙb信号通路，阻止Nlrp3炎症小体的激活或PKR1的表达有关。上述研究结果为颈动脉粥样硬化及其心脏并发症的发病机制和防治手段提供了全新的认识。