11β-羟化类固醇脱氢酶1促进3T3-L1前脂肪细胞分化

Effects of 11 beta-hydroxysteroid dehydrogenase type 1 on differentiation of 3T3-L1 preadipocyte

目的:应用3T3-L1细胞模型研究11β-羟化类固醇脱氢酶1(11β-HSD1)与前脂肪细胞分化的关系,探讨11β-HSD1在前脂肪细胞分化及肥胖中的作用。方法:构建11β-HSD1-SiRNA表达质粒pGCsilencerTMH1/TetO1-11β-HSD1并稳定转染3T3-L1细胞,采用油红染色观察脂滴堆积情况,采用Westernblot方法检测11β-HSD1在正常3T3-L1细胞分化过程中的表达;并用Real-timePCR检测脂肪细胞分化相关标志基因的变化,阐明11β-HSD1对前脂肪细胞成脂分化的影响。结果:正常3T3-L1前脂肪细胞在上述三联诱导分化后脂滴堆积随着分化过程逐渐增加;在pGCsilencerTMH1/TetO1-11β-HSD1转染的3T3-L1诱导分化过程中可见脂滴堆积的减少。在3T3-L1前脂肪细胞分化模型中(days0,2,4,6,8),11β-HSD1蛋白水平是上调的。3T3-L1前脂肪细胞分化模型中GR在分化模型早期(D4及D6)是上调的,但是在分化后期(D8)很快又下降。在正常3T3-L1前脂肪细胞分化早期LPL上调,随着分化后期FAS、PPARγ等明显上升,Pref-1作为脂肪细胞分化抑制因子,在分化早期升高,在分化后期明显下调。在pGCsilencerTMH1/TetO1-11β-HSD1转染后的3T3-L1细胞分化模型中上述有关标志基因发生变化。结论:11β-HSD1作为受体前调节剂促进前脂肪细胞分化,与肥胖和胰岛素抵抗相关。

Objective：To investigate the relationship between l l beta-hydroxysteroid dehydrogenase type 1 （1 lbeta-HSD1 ） and preadipocyte differentiation. Methods-The mouse llbeta-HSDlsiRNA plasmids were transfected into 3T3-L1 cells for the examination of the effect of targeted l lbeta-HSD1 inhibition on differentiation of 3T3-L1 cells. Differentiation was stimulated with 3-isobutyl-1-methyxanthine（MIX）, insulin and dexamethasone（DEX）. Oil Red O staining was used to observe the lipid accumulation. The genes expression was detected by real-time PCR and Western blot. Results：Lipid accumulation was significantly inhibited in cells transfected with mouse 1 lbeta-HSD1-siRNA compared with untransfected 3T3-L1 cells. Fewer lipid droplets were detected in transfected cells both prior to stimulation and after stimulation with differentiation-inducing reagents. The expression of adipocyte differentiation-associated markers such as lipoprotein lipase （LPL）, fatty acid synthetase （FAS） were downregulated in transfected cells. Similarly, the expression of preadipocyte factor-1 （Pref-1）, an inhibitor of adipocyte differentiation, was downregulated in transfected cells stimulated by MIX, insulin and dexamethasone. Conclusion： 1 lbeta-HSD1 can promote preadipocyte differentiation, and may be an important candidate mediator of obesity and obesity-induced insulin resistance.