高糖对人肾小球系膜细胞SREBP-1、FAS表达的影响

EFFECT OF HIGH GLUCOSE ON THE EXPRESSION OF SREBP-1 AND FAS IN HUMAN MESANGIAL CELLS

目的探讨高糖环境中人肾小球系膜细胞(human mesangial cells,HMC)SREBP-1、FAS表达。方法体外培养HMC细胞,随机分为正常糖组、高糖组,免疫细胞化学、Western Blot和RT-PCR方法检测固醇调节元件结合蛋白1(sterol regulatory element binding protein-1,SREBP-1)和脂肪酸合酶(fatty acid synthase,FAS)表达。采用脂质体转染技术将特异性SREBP-1质粒引入细胞内并进行表达,进一步采用RT-PCR方法检测脂肪酸合酶FAS的表达。结果与正常糖组比较,高糖培养的人肾小球系膜细胞固醇调节元件结合蛋白1前体和成熟体以及FAS mRNA表达均升高,差异有统计学意义。质粒转染后HMC细胞经免疫组化和Western blot检测证实特异性质粒能够在细胞内高表达SREBP-1蛋白,进一步对FAS的检测证实了FAS mRNA表达升高。结论高糖可诱导人肾小球系膜细胞固醇调节元件结合蛋白1和FAS表达增强且SREBP-1和FAS之间存在有直接关系。

Objective To investigate the effect of high glucose on SREBP-1 and FAS in human mesangial cells. Methods HMC cells were cultured using the 1640 medium supplemented with 10% FBS that was divided into 4 groups： normal glucose group, high glucose group, pcDNA3.1 plasmid group and pcD- NA3.1-SC1 plasmid group. The expression of sterol regulatory element binding protein-1 （SREBP-1） was detected with immunocytochemistry and Western Blot. FAS mRNA was detected by RT-PCR. Results Immunocytochemistry showed that high glucose induced increased expression of SREBP-1. The precursor and mature segment of SREBP-1 were detected with Western Blot, and both were increased in the presence of high glucose. The result of RT-PCR showed that FAS mRNA increased under the stimulation of high glucose. HMC cells were transfected with the specific SREBP-1 expression plasmid peDNA3. 1-SC1 by Lipofectamine 2000. At 48 h after transfection, high expression of SREBP-1 was testified by immunocytochemistry and Western blot. Furthermore, compared with that of the pcDNA3. 1 group, FAS mRNA increased in pcDNA3.1-SC1 group HMC cells. Conclusion The observations suggest that high glucose can induce the expressions of the precursor and mature segment of SREBP-1 in HMC cells that can up-regulate FAS mR- NA, which may play an important role in the pathogenesis of diabetic nephropathy.