TGF-β1/Smad7信号通路在白藜芦醇增强胆固醇酯水解酶表达中的作用

Role of TGF-β1/Smad7 in enhancement of cholesteryl ester hydrolase expression by resveratrol

目的探讨TGF-β1/Smad-7信号通路在白藜芦醇增强胆固醇酯水解酶(cholesteryl ester hydrolase,CEH)表达中的作用。方法用氧化低密度脂蛋白(oxidized low density lipoprotein,oxLDL)诱导小鼠单核巨噬细胞株RAW 264.7转化为泡沫细胞,将经泡沫化处理的巨噬细胞进行2次分组,第1次分为正常对照组、白藜芦醇组、LY2157299组和白藜芦醇+LY2157299组,第2次分为正常对照组、白藜芦醇组、Ad-Smad-7组和白藜芦醇+Ad-Smad-7组,均处理48 h,通过胆固醇流出试验检测各组巨噬细胞内胆固醇流出率,油红O染色检测细胞泡沫化情况,RT-PCR法和Western blot法检测细胞中p-Smad-7和CEH基因mRNA的转录水平及蛋白的表达水平。结果与正常对照组比较,白藜芦醇组巨噬细胞内胆固醇流出率明显升高(P<0.05),白藜芦醇+LY2157299组、LY2157299组、白藜芦醇+Ad-Smad-7组和Ad-Smad-7组胆固醇流出率均明显降低(P<0.05);白藜芦醇组巨噬细胞泡沫化程度明显下降(P<0.05),白藜芦醇+LY2157299组、LY2157299组、白藜芦醇+Ad-Smad-7组和Ad-Smad-7组巨噬细胞泡沫化程度明显增强(P<0.05);白藜芦醇组巨噬细胞中CEH基因mRNA的转录水平及蛋白的表达水平明显增强(P<0.05),p-Smad-7基因mRNA的转录水平及蛋白的表达水平明显下降(P<0.05),而白藜芦醇+LY2157299组、LY2157299组、白藜芦醇+Ad-Smad-7组和Ad-Smad-7组CEH基因mRNA的转录及蛋白的表达均明显被抑制(P<0.05),p-Smad-7基因mRNA的转录及蛋白的表达均明显增强(P<0.05)。结论白藜芦醇可能是通过TGF-β1/Smad-7信号通路来增强CEH的表达。

Objective To investigate the role of TGF-β1/Smad7 in enhancement of cholesteryl ester hydrolase （CEH） expression by resveratrol. Methods Mouse mononuclear macrophage RAW264. 7 strain was transformed to foam ceils by induction with oxidized low density lipoprotein （oxLDL）, and grouped for 2 times, i.e. normal control, resveratrol, LY2157299 and resveratrol ＋ LY2157299 groups in the first time, and normal control, resveratrol, Ad-Smad-7 and resveratrol ＋ Ad-Smad-7 groups in the second time. The cells in various groups were treated for 48 h, then determined for cholesteryl outflow rate by cholesteryl outflow test, for bubblization by oil red O staining, for transcription levels of p- Smad-7 and CEH mRNAs by RT-PCR, and for expression levels of p-Smad-7 and CEH proteins by Western blot. Results As compared with those in normal control group, the cholesteryl outflow rate in resveratrol group increased significantly （P 〈 0. 05）, while those in resveratrol ＋ LY2157299, LY2157299, resveratrol ＋ Ad-Smad-7 and Ad-Smad-7 groups de- creased significantly （P 〈 0. 05）; the bubblization levels of macrophages in resveratrol group decreased significantly （P 〈 0. 05）, while those in resveratrol ＋ LY2157299, LY2157299, resveratrol ＋ Ad-Smad-7 and Ad-Smad-7 groups increased significantly （P 〈 0. 05 ）; the mRNA transcription and protein expression levels of CEH in resveratrol group increased Sig-nificantly （P 〈 0. 05）, while those of p-Smad-7 decreased significantly （P 〈 0. 05）. However, both the mRNA transcrip- tion and protein expression of CEH in resveratrol ＋ LY2157299, LY2157299, resveratrol ＋ Ad-Smad-7 and Ad-Smad-7 groups were inhibited significantly （P 〈 0. 05）, while those of p-Smad-7 were enhanced significantly （P 〈 0. 05）. Con- clusion Resveratrol might enhance the expression of CEH by TGFβ1/Smad-7 signaling pathway.