Tian Miao, Han Yu-Bo, Zhao Cheng-Cheng, Liu Li, Zhang Fu-Li
Heilongjiang University of Chinese Medicine, Harbin, 150040, Heilongjiang, People's Republic of China.
The First Department of Cardiovascular, First Affiliated Hospital, Heilongjiang University of Chinese Medicine, No. 26 Heping Road , Xiangfang District, Harbin, 150040, Heilongjiang, People's Republic of China.
Diabetol Metab Syndr. 2021 Apr 29;13(1):50. doi: 10.1186/s13098-021-00664-1.
Hesperidin, a natural flavanone, has been proven to have multiple protective effects in diabetic rats, such as antioxidant, anti-inflammatory and anti-apoptotic effects. However, the molecular mechanisms underlying the effects of hesperidin are not well elucidated.
LO2 cells were stimulated with high glucose (HG, 33 mM) for 24 h to establish a model of oxidative stress. Then, cell viability was determined using the MTT assay. The antioxidant activities, including the reactive oxygen species (ROS), malondialdehyde (MDA), superoxide dismutase (SOD) and glutathione peroxidase (GPx) levels, mitochondrial membrane potential (MMP) and adenosine-triphosphate (ATP) production, were measured with the corresponding kits. The levels of gene expression, protein expression and methylation were detected using qRT-PCR, western blotting and methylation-specific PCR (MSP) assays, respectively.
Compared to the NG treatment, hesperidin treatment increased the viability and improved the oxidative stress, mitochondrial dysfunction and insulin resistance of HG-treated LO2 cells, and these effects were correlated with heightened SOD and GPx activities, increased MMP level and ATP generation, reduced MDA, ROS and glucose levels, and activated GSK3β/AKT and inactivated IRS1 signals. Mechanistically, hesperidin treatment enhanced the miR-149 expression level by reducing its promoter methylation by inhibiting DNMT1. Importantly, knockdown of miR-149 obviously abolished the biological roles of hesperidin.
Our findings demonstrated that hesperidin treatment ameliorated HG-induced insulin resistance by reducing oxidative stress and mitochondrial dysfunction partly by suppressing DNMT1-mediated miR-149 silencing.
橙皮苷是一种天然黄酮类化合物，已被证明对糖尿病大鼠具有多种保护作用，如抗氧化、抗炎和抗凋亡作用。然而，橙皮苷作用的分子机制尚未完全阐明。
用高糖（HG，33 mM）刺激LO2细胞24小时以建立氧化应激模型。然后，使用MTT法测定细胞活力。用相应试剂盒测量抗氧化活性，包括活性氧（ROS）、丙二醛（MDA）、超氧化物歧化酶（SOD）和谷胱甘肽过氧化物酶（GPx）水平、线粒体膜电位（MMP）和三磷酸腺苷（ATP）生成。分别使用qRT-PCR、蛋白质印迹和甲基化特异性PCR（MSP）检测基因表达、蛋白质表达和甲基化水平。
与正常葡萄糖（NG）处理相比，橙皮苷处理提高了HG处理的LO2细胞的活力，改善了氧化应激、线粒体功能障碍和胰岛素抵抗，这些作用与SOD和GPx活性增强、MMP水平和ATP生成增加、MDA、ROS和葡萄糖水平降低以及GSK3β/AKT激活和IRS1信号失活相关。机制上，橙皮苷处理通过抑制DNMT1减少其启动子甲基化来提高miR-149表达水平。重要的是，敲低miR-149明显消除了橙皮苷的生物学作用。
我们的研究结果表明，橙皮苷处理通过减轻氧化应激和线粒体功能障碍来改善HG诱导的胰岛素抵抗，部分是通过抑制DNMT1介导的miR-149沉默实现的。
