SIRT1通过降低NF-κB p65乙酰化减轻高糖应激引起的大鼠肾小球系膜细胞损伤*

 目的： 研究沉默信息调节因子1（SIRT1）对高糖诱导的大鼠肾小球系膜细胞NF-κB p65蛋白乙酰化影响及其保护作用。方法: 培养大鼠肾小球系膜细胞，实验分为5组：正常对照组、甘露醇组、高糖组、白藜芦醇组和SIRT1 RNAi组。MTT比色法检测细胞活性；以实时荧光定量PCR检测SIRT1、单核细胞趋化蛋白1（MCP-1）、血管黏附分子1（VCAM-1）、肿瘤坏死因子α（TNF-α）和转化生长因子β1（TGF-β1）mRNA水平；Western blotting检测SIRT1和NF-κB p65乙酰化蛋白的表达水平，ELISA检测MCP-1、VCAM-1、TNF-α、TGF-β1和丙二醛（MDA）的含量。结果: 高糖刺激使肾小球系膜细胞的活力降低，超氧化物岐化酶（SOD）活性降低，MDA含量增加；SIRT1 mRNA及蛋白表达降低，NF-κB p65蛋白乙酰化水平增高，MCP-1、VCAM-1、TNF-α、TGF-β1 mRNA和蛋白水平增高。白藜芦醇可逆转高糖引起的变化，而沉默SIRT1基因使高糖诱导的系膜细胞NF-κB p56乙酰化水平、MCP-1、VCAM-1、TNF-α、TGF-β1 mRNA和蛋白水平升高。结论: 高糖可降低SIRT1水平，增加炎症因子的表达。SIRT1的激活可使NF-κB 的亚单位RelA/p65去乙酰化，从而抑制炎症因子的产生。SIRT1可作为治疗DN的潜在靶点。

Protective effect of SIRT1 on rat mesangial cells by decreasing high glucose-induced acetylation of NF-κB p65

AIM: To investigate the effects of silent information regulator 1 (SIRT1) on high glucose-induced acetylation of NF-κB p65 subunit and its protective role in rat mesangial cells. METHODS: Rat mesangial cells were cultured in DMEM supplemented with 10% FBS and were divided into control group, mannitol group, high glucose group, resveratrol group and SIRT1 RNAi group. The cell viability was determined by MTT assay. The mRNA expression of SIRT1, monocyte chemoattratant protein 1 (MCP-1), vascular cell adhesion molecule 1 (VCAM-1-1), tumor necrosis factor α (TNF-α), transforming growth factor β1 (TGF-β1) was analyzed by real-time quantitative PCR. The protein expression of SIRT1 and the acetylation of NF-κB p65 subunit were determined by Western blotting. The protein concentrations of MCP-1, VCAM-1, TNF-α, TGF-β1 and malondialdehyde (MDA) were detected by ELISA. RESULTS: The cell viability, superoxide dismutase (SOD) activity, and the expression of SIRT1 at mRNA and protein levels were decreased by high glucose treatment as compared with control group. The acetylation of NF-κB p65 subunit was significantly increased after interfered with high glucose, resulting in the increase in the secretion of MCP-1, VCAM-1, TNF-α and TGF-β1. Resveratrol decreased high glucose-induced acetylation of NF-κB p65 subunit. However, silencing SIRT1 significantly enhanced the acetylation of NF-κB p65 subunit and the expression of MCP-1, VCAM-1, TNF-α and TGF-β1. CONCLUSION: SIRT1 remarkably inhibits the inflammatory reactions by deacetylating NF-κB p65, suggesting that SIRT1 is a possible target for preventing diabetic nephropathy.