Department of Pathophysiology and Therapeutics of Diabetic Vascular Complications, Kurume University School of Medicine, Kurume, Fukuoka, Japan.
Metabolism. 2012 Aug;61(8):1067-72. doi: 10.1016/j.metabol.2012.01.006. Epub 2012 Mar 3.
Advanced glycation end products (AGEs) and their receptor (RAGE) axis play a role in diabetic nephropathy. Statins have been shown to ameliorate renal function and reduce proteinuria in patients with chronic kidney disease. However, the effects of statin on AGEs-induced tubular cell damage remain unknown. We examined here whether and how pravastatin 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 analyzed in an enzyme-linked immunosorbent assay. Asymmetric dimethylarginine (ADMA) expression was evaluated by immunostaining. Pravastatin dose-dependently inhibited the AGEs-induced up-regulation of RAGE mRNA level, ROS generation and apoptosis in human renal proximal tubular cells. Further, AGEs decreased mRNA level of dimethylarginine dimethylaminohydrolase-2, an enzyme that mainly degrades asymmetric dimethylarginine (ADMA), an endogenous inhibitor of nitric oxide synthase and subsequently increased ADMA generation in tubular cells, both of which were also prevented by pravastatin. Geranylgeranyl pyrophosphate (GGPP) treatment blocked all of the effects of pravastatin on tubular cells. We found that rosuvastatin also significantly blocked the AGEs-induced increase in RAGE mRNA level and ROS generation, both of which were prevented by GGPP. Our present study suggests that pravastatin could inhibit the AGEs-induced apoptosis and ADMA generation in tubular cells by suppressing RAGE expression probably via inhibition of GGPP synthesis. Pravastatin may exert beneficial effects on tubular damage in diabetic nephropathy by blocking the AGEs-RAGE axis.
晚期糖基化终产物（AGEs）及其受体（RAGE）轴在糖尿病肾病中起作用。他汀类药物已被证明可改善慢性肾脏病患者的肾功能并减少蛋白尿。然而，他汀类药物对AGEs 诱导的肾小管细胞损伤的影响尚不清楚。我们在此研究了普伐他汀是否以及如何在体外阻断 AGEs-RAGE 诱导的肾小管细胞损伤。通过实时逆转录聚合酶链反应评估基因表达水平。通过二氢乙啶染色测量活性氧（ROS）的产生。通过酶联免疫吸附试验分析细胞凋亡。通过免疫染色评估不对称二甲基精氨酸（ADMA）的表达。普伐他汀呈剂量依赖性抑制 AGEs 诱导的人近端肾小管细胞中 RAGE mRNA 水平、ROS 生成和细胞凋亡的上调。此外，AGEs 降低了二甲基精氨酸二甲氨基水解酶-2 的 mRNA 水平，该酶主要降解不对称二甲基精氨酸（ADMA），ADMA 是一氧化氮合酶的内源性抑制剂，随后增加了肾小管细胞中 ADMA 的生成，这两种作用都被普伐他汀所阻止。香叶基香叶基焦磷酸（GGPP）处理阻断了普伐他汀对肾小管细胞的所有作用。我们发现，瑞舒伐他汀也显著阻断了 AGEs 诱导的 RAGE mRNA 水平和 ROS 生成的增加，这两种作用都被 GGPP 所阻止。我们的研究表明，普伐他汀可能通过抑制 GGPP 合成来抑制 RAGE 表达，从而抑制 AGEs 诱导的肾小管细胞凋亡和 ADMA 生成。普伐他汀可能通过阻断 AGEs-RAGE 轴对糖尿病肾病中的肾小管损伤发挥有益作用。
