Center for Experimental Medical Research, The Third Xiangya Hospital of Central South University, Changsha, Hunan, China.
Department of Cardiology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, China.
J Cell Mol Med. 2019 Feb;23(2):798-810. doi: 10.1111/jcmm.13975. Epub 2018 Nov 16.
The dipeptidyl peptidase 4 inhibitor vildagliptin (VLD), a widely used anti-diabetic drug, exerts favourable effects on vascular endothelium in diabetes. We determined for the first time the improving effects of VLD on mitochondrial dysfunction in diabetic mice and human umbilical vein endothelial cells (HUVECs) cultured under hyperglycaemic conditions, and further explored the mechanism behind the anti-diabetic activity. Mitochondrial ROS (mtROS) production was detected by fluorescent microscope and flow cytometry. Mitochondrial DNA damage and ATP synthesis were analysed by real time PCR and ATPlite assay, respectively. Mitochondrial network stained with MitoTracker Red to identify mitochondrial fragmentation was visualized under confocal microscopy. The expression levels of dynamin-related proteins (Drp1 and Fis1) were determined by immunoblotting. We found that VLD significantly reduced mtROS production and mitochondrial DNA damage, but enhanced ATP synthesis in endothelium under diabetic conditions. Moreover, VLD reduced the expression of Drp1 and Fis1, blocked Drp1 translocation into mitochondria, and blunted mitochondrial fragmentation induced by hyperglycaemia. As a result, mitochondrial dysfunction was alleviated and mitochondrial morphology was restored by VLD. Additionally, VLD promoted the phosphorylation of AMPK and its target acetyl-CoA carboxylase in the setting of high glucose, and AMPK activation led to a decreased expression and activation of Drp1. In conclusion, VLD improves endothelial mitochondrial dysfunction in diabetes, possibly through inhibiting Drp1-mediated mitochondrial fission in an AMPK-dependent manner.
二肽基肽酶 4 抑制剂维格列汀（VLD）是一种广泛应用于治疗糖尿病的抗糖尿病药物，它对糖尿病患者的血管内皮具有有益作用。我们首次确定了 VLD 对高血糖培养条件下糖尿病小鼠和人脐静脉内皮细胞（HUVEC）中线粒体功能障碍的改善作用，并进一步探讨了其抗糖尿病活性的机制。通过荧光显微镜和流式细胞术检测线粒体 ROS（mtROS）的产生。通过实时 PCR 和 ATPlite 测定分别分析线粒体 DNA 损伤和 ATP 合成。用 MitoTracker Red 染色线粒体网络以鉴定线粒体碎片化，在共聚焦显微镜下观察。通过免疫印迹测定动力相关蛋白（Drp1 和 Fis1）的表达水平。我们发现 VLD 可显著减少糖尿病状态下内皮细胞中线粒体 ROS 的产生和线粒体 DNA 损伤，但可增强 ATP 合成。此外，VLD 降低了 Drp1 和 Fis1 的表达，阻断了 Drp1 向线粒体的易位，并减弱了高血糖诱导的线粒体碎片化。结果，VLD 减轻了线粒体功能障碍并恢复了线粒体形态。此外，VLD 促进了高葡萄糖环境中 AMPK 的磷酸化及其靶标乙酰辅酶 A 羧化酶，而 AMPK 的激活导致 Drp1 的表达和活性降低。总之，VLD 改善了糖尿病患者的内皮线粒体功能障碍，可能通过 AMPK 依赖性抑制 Drp1 介导的线粒体分裂来实现。
