转化生长因子B受体Ⅰ影响脂肪细胞分化的研究

The effect of transforming growth factor B receptor typeⅠon adipocyte differentiation

目的探讨siRNA下调转化生长因子β受体Ⅰ(TGFBRⅠ)基因表达后对ST2细胞向脂肪细胞分化的作用。方法设计并合成针对TGFBRⅠ的靶向si RNA作为实验组,以转染Control si RNA作为对照组。应用q RT-PCR检测并比较转染ST2细胞后各组TGFBRⅠm RNA的表达和脂肪细胞特异性转录因子CCAAT增强子结合蛋白(C/EBP)α、过氧化物酶体增殖物激活受体(PPAR)γ、脂肪细胞表征因子FABP4 m RNA的表达水平。诱导5 d后对2组细胞进行油红O染色,检测TGFBRⅠsi RNA对ST2细胞分化的影响。利用激光共聚焦显微镜观察脂肪细胞的染色情况并对细胞进行拍照。另外,用异丙醇萃取出油红O,测定油红O在波长520 nm处的光密度(OD)值,并进行组间比较。结果转染TGFBRⅠsi RNA后,ST2细胞TGFBRⅠ基因的表达水平明显下调,TGFBRⅠsi RNA能够促进脂肪细胞生成,增强C/EBPα、PPARγ及FABP4 m RNA表达;经成脂诱导5 d后,转染TGFBRⅠsi RNA的细胞产生的脂滴明显较Control si RNA组多,且OD值高于Control si RNA组。结论 TGFBRⅠsi RNA能有效促进脂肪细胞的分化,提示TGFBRⅠ可能是前体细胞向脂肪细胞分化的重要调控因子。

Objective To investigate the effect of transforming growth factor β receptor type Ⅰ （TGFBRⅠ） on adipocytedifferentiation by using a small interference RNA （siRNA）. Methods The siRNA targeting TGFBRⅠwas synthesized asexperimental group, and negative control siRNA was used as control group. The efficiency of TGFBRⅠ depletion and theexpression levels of adipocyte- specific transcription factors CCAAT enhancer binding protein α （C/EBPα）,peroxisomeproliferator- activated receptor gamma （PPARγ） and adipocyte marker gene fatty acid binding protein 4 （FABP4） weredetected by quantitative real-time PCR. After treating with adipocyte differentiation agents for 5 days, the cells were stainedwith oil red O, and the staining of adipocyte was observed and photographed by laser confocal microscope. In addition, withisopropanol extracted oil red O, optical density values of oil red O were measured at a wavelength of 520, and which werecompared between groups. Results After transfection of TGFBR Ⅰ siRNA, gene expression levels of TGFBR Ⅰ weresignificantly reduced in ST2 cells, the number of differentiated adipocytes was significantly increased, and the mRNA levelsof adipocyte specific transcription factor C/EBP α and PPARγ and adipocyte marker gene FABP4 were enhanced comparedwith those of control group. After treating with adipocyte differentiation agents for 5 days,the number of lipid droplets of cellswith transfection of TGFBRⅠsiRNA was increased than that of cells with transfection of control siRNA. The value of opticaldensity was higher in cells with transfection of TGFBRⅠsiRNA than that of control siRNA group. Conclusion TGFBRⅠsiRNA can effectively facilitate adipocyte formation, which suggests that TGFBRⅠis an important regulator of adipogenicdifferentiation from progenitor cells.