Zanetti Michela, Stocca Alessia, Dapas Barbara, Farra Rossella, Uxa Laura, Bosutti Alessandra, Barazzoni Rocco, Bossi Fleur, Giansante Carlo, Tedesco Francesco, Cattin Luigi, Guarnieri Gianfranco, Grassi Gabriele
UCO Clinica Medica-DSCMT, Ospedale di Cattinara, Strada di Fiume 447, 34100, Trieste, Italy.
J Mol Med (Berl). 2008 Feb;86(2):185-95. doi: 10.1007/s00109-007-0257-3. Epub 2007 Sep 18.
Fenofibrate has beneficial effects on the progression and clinical emergence of atherosclerosis in normoglycemic and in diabetic patients. Given the involvement of endothelium in these processes, we speculated that fenofibrate may influence endothelial cell apoptosis and proliferation, regulators of endothelium integrity. Fenofibrate effects on apoptosis and proliferation were studied in human umbilical vein endothelial cells under normal (5.5 mmol/l, NG) and high (22 mmol/l, HG) glucose with or without fenofibrate (50 micromol/l). Apoptosis was evaluated by annexin V, by poly(ADP-ribose) polymerase protein cleavage, and cyclooxygenase-2 (COX-2), Bax/Bcl-2, and p53 protein levels; proliferation was assessed by determining cell cycle phase distribution and the amounts of the cell cycle regulators E2F1, cyclin D1, E1, and A and the levels of the hyper-phosphorylated form of the retinoblastoma protein (ppRb). HG resulted in increased (p<0.05) apoptosis rate associated with COX-2 protein overexpression, without modification of Bax/Bcl2 ratio and p53 levels. Fenofibrate decreased apoptosis and normalized increased COX-2 expression in HG (p<0.05). Both in HG and NG, fenofibrate dramatically reduced cell proliferation (p<0.05) through a G1/G0 block mediated by the reduction in ppRb and the decrease in E2F1, cyclin E1, A, and D1 protein expression, with a mechanism that, for cyclin E1, occurred at the posttranscriptional level. In conclusion, our data show that fenofibrate reduces apoptosis caused by HG but severely interferes with endothelial cell proliferation both in NG and HG. The resulting effect may influence endothelium integrity in vivo and may impact the outcome of acute complications of atherosclerosis in diabetes.
非诺贝特对血糖正常和糖尿病患者动脉粥样硬化的进展及临床发生具有有益作用。鉴于内皮细胞参与这些过程，我们推测非诺贝特可能影响内皮细胞凋亡和增殖，而这两者是内皮完整性的调节因子。在正常（5.5 mmol/L，NG）和高糖（22 mmol/L，HG）条件下，使用或不使用非诺贝特（50 μmol/L）研究其对人脐静脉内皮细胞凋亡和增殖的影响。通过膜联蛋白V、聚（ADP - 核糖）聚合酶蛋白裂解、环氧合酶 - 2（COX - 2）、Bax/Bcl - 2和p53蛋白水平评估凋亡；通过测定细胞周期阶段分布以及细胞周期调节因子E2F1、细胞周期蛋白D1、E1和A的量以及视网膜母细胞瘤蛋白（ppRb）的高磷酸化形式水平评估增殖。HG导致凋亡率增加（p<0.05），与COX - 2蛋白过表达相关，而Bax/Bcl2比值和p53水平未改变。非诺贝特可降低HG条件下的凋亡，并使升高的COX - 2表达恢复正常（p<0.05）。在HG和NG条件下，非诺贝特均通过由ppRb减少介导的G1/G0期阻滞以及E2F1、细胞周期蛋白E（原文误写为E1）、A和D1蛋白表达降低，显著降低细胞增殖（p<0.05），其机制对于细胞周期蛋白E1而言发生在转录后水平。总之，我们的数据表明非诺贝特可降低HG引起的凋亡，但在NG和HG条件下均严重干扰内皮细胞增殖。由此产生的效应可能影响体内内皮完整性，并可能影响糖尿病动脉粥样硬化急性并发症的结局。
