具核梭杆菌与动脉粥样硬化的关系及机制研究

Chronic periodontitis, an independent risk factor of cardiovascular disease, could increase the risk of atherosclerosis. F. nucleatum is one of the pathogenic bacteria of chronic periodontitis. Recent studies showed that F. nucleatum was not only able to survive in VECs, affect cellular function of VECs, but could also induce cell death in human lymphocytes. Based on the previous research, we plan to explore the capacity of F. nucleatum to modulate the expressions of adhesion molecules, chemokine, inflammatory factors of HAECs/THP-1 cells and quantification of foam cell formation in vitro and animal experiment. This study is to determine whether F. nucleatum induces factors predisposing to HAECs, THP-1 cells and atherosclerotic lesions in ApoE-/- mice. We also attempt to throw light on the roles of miR-21 and out membrane proteins of F. nucleatum. Aiming to look for molecular evidence of the association between periodontitis and atherosclerosis, we hope that our findings will contribute to the understanding of the etiology of cardiovascular disease and may thus have implications for its prevention and treatment.

慢性牙周炎是心血管疾病的独立危险因素，可大大增加动脉粥样硬化(AS)的患病风险。具核梭杆菌(F. nucleatum)是重要的牙周致病菌之一。已有研究发现F. nucleatum不仅有在内皮宿主细胞内生存、影响内皮细胞的功能，还可诱导外周血单核细胞和中性粒细胞的凋亡。本研究拟在前期研究的基础上，观察F. nucleatum对血管内皮细胞和外周血单核细胞增殖、分化的影响及对AS相关的黏附、趋化、炎症因子的影响，探究 miR-21和F. nucleatum外膜蛋白在其中的作用，并构建ApoE-/-小鼠牙周炎模型进行验证，以系统探究F. nucleatum侵袭对血管内皮细胞和外周血单核细胞的影响和作用机制。研究结果将有助于进一步明确牙周炎与AS的关联机制，并为心血管疾病的预防工作提供新的思路。

牙周炎是一种口腔慢性炎症性疾病，据报道与动脉粥样硬化疾病的发病机制和发展过程有明显的相关性。具核梭杆菌（F. nucleatum）是一种重要的牙周共生病原菌，与多种牙周疾病密切相关;然而，具核梭杆菌在动脉粥样硬化发病机制中的作用尚不清楚。本研究旨在阐明F. nucleatum促动脉粥样硬化的潜在致病机制，为动脉粥样硬化的预防和治疗提供新的思路。我们利用ApoE−/−小鼠建立牙周感染模型，并通过体外共培养模型评估F. nucleatum在泡沫细胞形成过程中的致病性。结果表明，F. nucleatum ATCC 25586可侵入主动脉组织，明显增加动脉粥样硬化病变的进展。此外，F. nucleatum使斑块向不稳定表型转换，病理表现为内皮下层巨噬细胞浸润、M1型巨噬细胞极化、脂质沉积、细胞凋亡增多，细胞外基质和胶原含量减少。F. nucleatum感染组血清中白细胞介素IL-6、IL-1β、肿瘤坏死因子TNF-α、单核细胞趋化蛋白-1 (MCP-1)、c反应蛋白(CRP)、氧化性低密度脂蛋白(ox-LDL)和microRNAs (miR-146a、miR-155和miR-23b)水平显著升高。而HDL-c水平降低。F. nucleatum诱导体外巨噬细胞凋亡具有时间和剂量依赖性。F. nucleatum通过调节脂质代谢相关基因(AR-A1、ACAT1、ABCA1和ABCG1)的表达，促进ox-LDL诱导的胆固醇吞噬和积累。F. nucleatum通过显著增加泡沫细胞形成过程中IL-6、IL-1β、TNF-α、MCP-1和MMP-2、8和9的水平以及抑制纤维连接蛋白(FN) 1的水平，进一步恶化动脉粥样硬化斑块微环境。本研究表明，F. nucleatum ATCC 25586通过引起巨噬细胞的异常激活和脂质代谢参与动脉粥样硬化。因此，该研究显示了牙周炎和动脉粥样硬化之间的联系。