Department of Internal Medicine and Bioregulatory Science, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan.
Department of Internal Medicine and Bioregulatory Science, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan; Innovation Center for Medical Redox Navigation, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan.
Atherosclerosis. 2014 Jan;232(1):156-64. doi: 10.1016/j.atherosclerosis.2013.10.025. Epub 2013 Nov 5.
Metformin and glucagon like peptide-1 (GLP-1) prevent diabetic cardiovascular complications and atherosclerosis. However, the direct effects on hyperglycemia-induced oxidative stress in endothelial cells are not fully understood. Thus, we aimed to evaluate the effects of metformin and a GLP-1 analog, liraglutide on high glucose-induced oxidative stress.
Production of reactive oxygen species (ROS), activation of protein kinase C (PKC) and NAD(P)H oxidase, and changes in signaling molecules in response to high glucose exposure were evaluated in human aortic endothelial cells with and without treatment of metformin and liraglutide, alone or in combination. PKC-NAD(P)H oxidase pathway was assessed by translocation of GFP-fused PKCβ2 isoform and GFP-fused p47phox, a regulatory subunit of NAD(P)H oxidase, in addition to endogenous PKC phosphorylation and NAD(P)H oxidase activity.
High glucose-induced ROS overproduction was blunted by metformin or liraglutide treatment, with a further decrease by a combination of these drugs. Exposure to high glucose caused PKCβ2 translocation and a time-dependent phosphorylation of endogenous PKC but failed to induce its translocation and phosphorylation in the cells treated with metformin and liraglutide. Furthermore, both drugs inhibited p47phox translocation and NAD(P)H oxidase activation, and prevented the high glucose-induced changes in intracellulalr diacylglycerol (DAG) level and phosphorylation of AMP-activated protein kinase (AMPK). A combination of these drugs further enhanced all of these effects.
Metformin and liraglutide ameliorate high glucose-induced oxidative stress by inhibiting PKC-NAD(P)H oxidase pathway. A combination of these two drugs provides augmented protective effects, suggesting the clinical usefulness in prevention of diabetic vascular complications.
二甲双胍和胰高血糖素样肽-1（GLP-1）可预防糖尿病心血管并发症和动脉粥样硬化。然而，它们对内皮细胞高血糖诱导的氧化应激的直接作用尚不完全清楚。因此，我们旨在评估二甲双胍和 GLP-1 类似物利拉鲁肽对高糖诱导的氧化应激的影响。
用和不用二甲双胍和利拉鲁肽单独或联合处理人主动脉内皮细胞，评估这些细胞在高糖暴露下活性氧（ROS）的产生、蛋白激酶 C（PKC）和 NAD（P）H 氧化酶的激活以及信号分子的变化。PKC-NAD（P）H 氧化酶途径通过 GFP 融合 PKCβ2 同工型和 NAD（P）H 氧化酶的调节亚基 GFP 融合 p47phox 的转位以及内源性 PKC 磷酸化和 NAD（P）H 氧化酶活性来评估。
高糖诱导的 ROS 过度产生被二甲双胍或利拉鲁肽处理所抑制，联合使用这两种药物则进一步降低。高糖暴露导致 PKCβ2 转位和内源性 PKC 的时间依赖性磷酸化，但在用二甲双胍和利拉鲁肽处理的细胞中未能诱导其转位和磷酸化。此外，这两种药物均抑制 p47phox 转位和 NAD（P）H 氧化酶激活，并防止高糖诱导的细胞内二酰基甘油（DAG）水平和 AMP 激活蛋白激酶（AMPK）磷酸化的变化。联合使用这两种药物进一步增强了所有这些作用。
二甲双胍和利拉鲁肽通过抑制 PKC-NAD（P）H 氧化酶途径改善高糖诱导的氧化应激。这两种药物的联合使用提供了增强的保护作用，表明其在预防糖尿病血管并发症方面具有临床应用价值。
