Metformin Inhibits Advanced Glycation End Products (AGEs)-induced Renal Tubular Cell Injury by Suppressing Reactive Oxygen Species Generation via Reducing Receptor for AGEs (RAGE) Expression
Metformin Inhibits Advanced Glycation End Products (AGEs)-induced Renal Tubular Cell Injury by Suppressing Reactive Oxygen Species Generation via Reducing Receptor for AGEs (RAGE) Expression
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DOI：
10.1055/s-0032-1321878
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发表时间：
2012-11-01
影响因子：
2.2
通讯作者：
Yamagishi, S.
中科院分区：
文献类型：
--
作者：
Ishibashi, Y.;Matsui, T.;Yamagishi, S.
晚期糖基化终产物（AGEs）及其受体（AGEs）在糖尿病肾病肾小管间质损害中起重要作用。最近，二甲双胍在细胞培养和糖尿病动物模型中都显示出改善肾小管损伤。然而，二甲双胍对AGEs诱导的肾小管细胞凋亡和损伤的影响仍不清楚。我们在此研究了二甲双胍是否以及如何在体外阻断AGEs诱导的肾小管细胞损伤。通过实时逆转录聚合酶链反应评价基因表达水平。用二氢乙锭染色测量活性氧（ROS）的产生。通过DNA片段化和膜联蛋白V表达水平评价细胞凋亡。AGEs上调人肾近端小管细胞中的AGEs mRNA水平，随后增加ROS生成和细胞间粘附分子-1、单核细胞趋化蛋白-1和转化生长因子-β基因表达，所有这些均被0.01和0.1 mM二甲双胍治疗显著阻断。化合物C是AMP活化蛋白激酶的抑制剂，可显著阻断二甲双胍对AGEs暴露的肾小管细胞中的β-内酰胺酶基因表达和ROS生成的影响。此外，二甲双胍剂量依赖性地抑制AGEs诱导的肾小管细胞凋亡; 1 mM二甲双胍在2种不同的试验系统中完全抑制AGEs的促凋亡作用。我们目前的研究表明，二甲双胍可以抑制AGEs诱导的肾小管细胞凋亡和炎症和纤维化反应，可能是通过减少ROS的产生，通过抑制cAMP的表达，通过AMP激活的蛋白激酶激活。二甲双胍可能通过阻断AGEs-β-ROS轴来保护糖尿病肾病中的肾小管细胞损伤。
Advanced glycation end products (AGEs) and their receptor (RAGE) play a role in tubulointerstitial damage in diabetic nephropathy. Recently, metformin has been shown to ameliorate tubular injury both in cell culture and diabetic animal model. However, effects of metformin on AGEs-induced tubular cell apoptosis and damage remain unknown. We examined here whether and how metformin could block the AGEs-RAGE-elicited tubular cell injury in vitro. Gene expression level was evaluated by real-time reverse-transcription polymerase chain reactions. Reactive oxygen species (ROS) generation was measured with dihydroethidium staining. Apoptosis was evaluated by DNA fragmentation and annexin V expression level. AGEs upregulated RAGE mRNA levels and subsequently increased ROS generation and intercellular adhesion molecule-1, monocyte chemoattractant protein-1 and transforming growth factor-beta gene expression in human renal proximal tubular cells, all of which were significantly blocked by the treatment of 0.01 and 0.1 mM metformin. Compound C, an inhibitor of AMP-activated protein kinase significantly blocked the effects of metformin on RAGE gene expression and ROS generation in AGEs-exposed tubular cells. Furthermore, metformin dose-dependently inhibited the AGEs-induced apoptotic cell death of tubular cells; 1 mM metformin completely suppressed the proapoptotic effects of AGEs in 2 different assay systems. Our present study suggests that metformin could inhibit the AGEs-induced apoptosis and inflammatory and fibrotic reactions in tubular cells probably by reducing ROS generation via suppression of RAGE expression through AMP-activated protein kinase activation. Metformin may protect against tubular cell injury in diabetic nephropathy by blocking the AGEs-RAGE-ROS axis.