SIRT1与CXCL16在巨细胞病毒致脑动脉粥样硬化易损斑块中的作用及机制研究

Cytomegalovirus infection plays an important role in atherosclerosis process, which often leads to atherosclerosis plaque formation, vulnerable plaque rupture, vascular stenosis, and increased the risk of the acute cerebrovascular events. However, the pathogenesis involved in cytomegalovirus-induced atherosclerosis remains unclear now. Our previous studies indicated that SIRT1 inhibits cytomegalovirus-induced angiogenesis, which is beneficial to plaque stability. Besides, the data from our preliminary experiment pointed that (1) cytomegalovirus UL83 gene could inhibit the expression of SIRT1 protein with upregulation of CXCL16, and (2) CXCL16 could enhance cytomegalovirus-induced ox-LDL uptake. Therefore, we hypothesized that cytomegalovirus UL83 gene promoted CXCL16-induced ox-LDL uptake through suppression of SIRT1, which further resulted in instable atherosclerotic plaque. Moreover, SIRT1 may have an inhibitory effect on this pathway, but the relevant results in vivo are not clear. As a result, we will explore the roles of SIRT1 and CXCL16 in cytomegalovirus-induced ox-LDL uptake in vitro and vivo by use of molecular biology technology such as lentivirus transfection, flow cytometry, gene chip. Our study is of great significance on illustration the mechanism of cytomegalovirus-induced instable atherosclerosis plaque. The study findings will provide new ideas to seek new therapeutic targets of the cerebrovascular diseases.

巨细胞病毒可导致动脉粥样硬化易损斑块形成、破裂及血管狭窄，危害极大，迄今对其致病机制研究不够深入。我们既往研究发现：SIRT1能抑制巨细胞病毒感染导致的血管新生，对促进易损斑块稳定有一定作用。另外，我们预实验结果提示：1. 巨细胞病毒UL83基因抑制SIRT1蛋白表达，促进CXCL16表达上调；2. CXCL16促进巨细胞病毒介导的ox-LDL胞内摄取。据此推测：巨细胞病毒UL83基因通过调控SIRT1促进CXCL16介导的ox-LDL摄取，最终导致易损斑块形成及破裂，SIRT1可能是抑制这一作用途径的靶点，但动物实验结果尚不清楚。因此，本课题将通过细胞和动物的病毒感染模型，采用慢病毒转染、流式细胞、基因芯片和测序等手段，探讨SIRT1和CXCL16在巨细胞病毒介导ox-LDL摄取过程中作用及机理。这对阐明巨细胞病毒介导的易损斑块破裂的发病机制，寻找早期有效治疗靶点具有重要意义。

脂质异常沉积是动脉粥样硬化形成及发展的原因之一，既往研究显示巨细胞病毒感染可介导内皮组织异常摄入脂质，此现象在器官移植患者等免疫抑制或免疫缺陷人群中较常见，但具体机制不清，需进一步研究。本研究进一步探讨了巨细胞病毒感染血管内皮后脂质摄入异常的分子调控机制。我们发现巨细胞病毒感染内皮细胞后，细胞内SIRT1蛋白表达下调，间接导致miR-340-3p表示水平抑制，对清道夫受体CXCL16的3端非编码区域吸附减弱，导致其表达上升。实验显示SIRT1与CXCL16蛋白之间无相互直接作用。该调控机制不仅使细胞摄入ox-LDL升高，而且细胞表型也发生变化，比如细胞增殖能力降低，迁移和成管能力减弱。我们还发现病毒编码UL83蛋白也可间接导致SIRT1蛋白的表达降低，但无直接结合作用，具体调节机制还需进一步研究。此外，我们也发现细胞摄入ox-LDL后，细胞内环状RNA0003204表达也升高，可以反向抑制miR-340-3p，但无直接吸附作用。总之，我们实验结果发现巨细胞病毒感染内皮后，其自身蛋白UL83能抑制SIRT1表达，通过miR-340-3p促进CXCL16表达上升，导致脂质摄入异常，进而导致内皮细胞表型异常，同时细胞内环状RNA0003204表达上升。. 我们研究结果拓展了人巨细胞病毒导致内皮细胞脂质摄入异常的分子机制，发现并证实了潜在的标记物，为人巨细胞病毒感染导致动脉硬化性血管病的预防及治疗提供了可能的生物靶点。