牙周致病菌 porphyromonas gingivalis在動脈硬化中誘導細胞表現Egr-1及Cyr61之機轉

Abstract

根據行政院衛生署統計民國96年國人十大死因，心臟疾病與腦血管疾病分別位居第二及第三名，嚴重威脅國人健康。近年研究顯示細菌感染可能是血管發生病變的原因之一，其中牙周病亦與心血管疾病具密切相關性。 Porphyromonas gingivalis (P.g.)是造成牙周病的致病菌之一，文獻指出P.g.會隨血液在血管裡流動，出現在動脈硬化發生的區域。 最近研究發現，粥狀動脈硬化斑塊處有大量的Cyr61及Egr-1表現。Cyr61表現量的多寡與動脈硬化惡化程度呈正比，Cyr61及Egr-1 刪除鼠可以抑制粥狀動脈硬化動物模式的粥狀動脈硬化發生。 本研究探討P.g. 誘導Cyr61及Egr-1表現產生動脈硬化的可能性。 我們首先以1ug/ml P.g. 脂多醣( LPS)處理人類血管平滑肌細胞(VSMC) ，發現LPS會誘導Cyr61及Egr-1的蛋白與mRNA表現。在VSMC中ROS並非Cyr61及Egr-1的誘導來源，但利用Bay (NF-kB抑制劑)、PD98059、SP600125、SB203580(ERK、JNK、p38抑制劑) 及Epigallocatechin gallate (EGCG)前處理可阻斷P.g. LPS誘導的Cyr61蛋白表現。可見得MAPKs訊息傳遞路徑在VSMC誘導的Cyr61蛋白表現中扮演了重要活化角色。然而由P.g. LPS誘導的Egr-1蛋白表現只受到SP600125及curcumin (AP-1抑制劑)的抑制。在粥狀動脈硬化微環境中有大量吞噬細胞存在，因此我們以1ug/ml P.g. LPS處理人類單核球細胞株THP-1亦發現它會誘導Cyr61及Egr-1的蛋白與mRNA表現。以PD98059、SP600125、Bay、抗氧化劑N- acetylcysteine及EGCG前處理可阻斷LPS誘導的Cyr61蛋白表現。在Egr-1蛋白的部分與VSMC結果相同，Egr-1蛋白表現只受到SP600125及curcumin的抑制。本研究首次指出P.g. LPS可誘導血管平滑肌細胞及人類單核球細胞 Cyr61及Egr-1蛋白之表現。 其訊息傳遞路徑可能經由ROS及MAPKs路徑。冀望未來可以藉由抑制這些訊息傳遞路徑成員來抑制與牙周病相關的動脈硬化。

According to the 2007 census of department of health, Executive Yuan, ROC, heart disease and cerebral vascular disease rank second and third among ten leading causes of death, respectively. Epidemiological studies have shown that periodontal disease is associated with increased risk for cardiovascular and cerebrovascular disease. With Porphyromonas gingivalis (P.g.) as the most important periodontal pathogen, this organism can accelerate atheroma deposition in animal models. However, the detail mechanism remains unknown. Previous studies have shown that Cyr61 and Egr-1 are highly expressed in human atherosclerotic plaques, correlating with the degree of stenosis and plaque histopathology. Inhibition of Cyr61 and Egr-1 gene expression reduces neointimal hyperplasia following balloon injury in rats. Here we show 1μg/ml P. g. LPS markedly induces Cyr61 and Egr-1 in mRNA and protein level in human vascular smooth muscle cell (VSMC) and human monocytic THP-1 cells. Pretreatment with NF-kB inhibitor Bay 11-7082, ERK inhibitor PD98059, JNK inhibitor SP600125, p38 MAPK inhibitor SB203580 and antioxidant epigallocatechin gallate (EGCG) significantly reduced P. g. LPS-induced Cyr61 in human vascular smooth muscle cells (VSMC), whereas the induction of Egr-1 via P. g. LPS only affected by SP600125 and curcumin (AP-1 inhibitor). In THP-1 cells, pretreatment with ROS inhibitor NAC, Bay 11-7082, PD98059, SP600125 and EGCG significantly reduced P. g. LPS-induced Cyr61, but not SB203580. The induction of Egr-1 by P. g. LPS in THP-1 also affected by SP600125 and curcumin. In conclusion, our results provide the first evidence that chronic P.g. infection may contribute to atherogenesis through sustained upregulation of Cyr61 and Egr-1.