KLF4通过上调Mfn2表达减轻棕榈酸致L6骨骼肌细胞的胰岛素抵抗

KLF4 ameliorates Palmitate-induced insulin resistance partially by up-regulating Mfn2 expression in L6 skeleton muscle cells

目的探讨Krüppel样因子(KLF)4通过调控线粒体融合蛋白(Mfn)2的表达对大鼠L6骨骼肌细胞胰岛素抵抗的影响。方法采用棕榈酸诱导法建立大鼠L6骨骼肌细胞的胰岛素抵抗模型,随机分为对照组和转染组。对照组转染腺病毒空载体(Ad),转染组转染KLF4腺病毒表达载体(Ad-KLF4)和(或)靶向Mfn2的小干扰RNA(Ad-Mfn2-siRNA)。采用Real-time PCR和Western印迹检测两组KLF4、Mfn2、胰岛素受体(IR)和葡萄糖转运蛋白(GLUT)4的表达水平,采用葡萄糖氧化酶法检测两组培养液中的葡萄糖浓度。结果与对照组比较,棕榈酸诱导组对葡萄糖的摄取量显著降低,KLF4、Mfn2、IR、GLUT4表达显著下调。KLF4过表达可显著提高细胞对胰岛素的敏感性,并上调Mfn2、IR、GLUT4表达。利用siRNA沉默Mfn2基因可明显阻断KLF4的作用。结论 KLF4可改善骨骼肌细胞的胰岛素抵抗,其机制可能与上调Mfn2表达有关。

Objective To investigate the effect of Kr üppel-like factor 4 ( KLF4 ) on palmitate-induced insulin resistance of rat L 6 skeleton muscle cells.Methods L6 Skeleton muscle cells were treated with palmitic acid and were divided into control and experiment groups.The differentiated L6 skeleton muscle cells were infected with control or KLF 4 adenovirus and/or Mfn2 siRNA expression adenovi-rus.The cell insulin sensitivities were evaluated by glucose consumption measured with glucose oxidase method .The expression levels of KLF4,Mfn2,insulin receptor (IR)and glucose transporter type 4 (GLUT4) were detected by Real-time PCR and Western-blot in skeleton muscle and L6 cells.Results Compared to those of control group ,the expressions of KLF4,MFN2,IR and GLUT4 were down-regulated by palmitic acid,and the insulin sensitivities of L6 cells were decreased by palmitate.By over-expression of KLF4,the insulin sensitivities was improved,and the expression levels of Mfn2,IR and GLUT4 were up-regulated,which were abrogated after knock-down the expression of Mfn2 by specific siRNA expression adenovirus .Conclusions KLF4 over-expression could ameliorate the insulin sensitivities of L 6 cells effectively and the mechanism possibly associated with the up-regulation of Mfn2.