血管紧张素-(1-7)通过AC-cAMP途径增加THP-1源性泡沫细胞ABCA1的表达并减少细胞胆固醇含量

目的: 构建THP-1源性泡沫细胞模型,探讨血管紧张素-(1-7) 和腺苷酸环化酶抑制剂MDL对THP-1源性泡沫细胞胆固醇逆转运相关蛋白——ATP结合盒转运子A1(ABCA1)表达和胆固醇含量的影响。方法: 将THP-1源性单核细胞诱导为巨噬细胞,加入氧化低密度脂蛋白(ox-LDL)建立泡沫细胞模型。实验分为4组:正常泡沫细胞组、MDL组、Ang-(1-7)组和MDL+Ang-(1-7)组。处理24 h后,分别通过ELISA法、荧光定量PCR法和Western blotting检测各组细胞cAMP表达水平、ABCA1 mRNA相对表达量和蛋白含量,闪烁计数法检测各组细胞胆固醇流出率,高效液相色谱法检测各组细胞胆固醇含量。结果: (1)Ang-(1-7)组cAMP表达水平、ABCA1 mRNA相对表达量和蛋白含量较泡沫细胞组有明显升高(P<0.05),胆固醇流出率较泡沫细胞组明显增高(P<0.05),胆固醇含量较泡沫细胞组显著降低(P<0.05)。(2)MDL组cAMP表达水平、ABCA1 mRNA相对表达量和蛋白含量较泡沫细胞组有明显降低(P<0.05),胆固醇流出率较泡沫细胞组明显降低(P<0.05),胆固醇含量较泡沫细胞组增高(P<0.05)。(3)MDL+Ang-(1-7)组数值介于Ang-(1-7)组与泡沫细胞组之间。结论: (1)Ang-(1-7)能促进泡沫细胞ABCA1的表达增加,促进胆固醇外流,减少泡沫细胞胆固醇含量,逆转泡沫细胞的形成。(2) MDL可以抑制腺苷酸环化酶的活性,减少cAMP的生成,从而部分拮抗Ang-(1-7)的上述作用,但不能完全阻断Ang-(1-7)的作用。

Angiotensin-(1-7) increases expression of ABCA1 and decreases content of cholesterol in THP-1-derived foam cells via AC-cAMP pathway

AIM: To establish the THP-1-derived foam cell formation and to evaluate the effects of angiotensin-(1-7)Ang-(1-7)] and MDL(an inhibitor of adenylate cyclase) on the expression of ATP-binding cassete transporter A1(ABCA1) and the content of cholesterol.METHODS: THP-1-derived macrophages were treated with oxidized low-density lipoprotein(ox-LDL) to develop into foam cells.The foam cells were divided into 4 groups: control group,MDL group,Ang-(1-7) group and MDL+Ang-(1-7) group.At 24 h after treatment,the content of cAMP was measured by ELISA.The mRNA and protein levels of ABCA1 were determined by real-time RT-PCR and Western blotting,respectively.The content of cholesterol was detected by high performance liquid chromatography.RESULTS: The cAMP,the mRNA and protein levels of ABCA1 in Ang-(1-7) group were significantly higher,and the content of cholesterol was significantly lower than those in control group(P<0.05).On the contrary,the cAMP,the mRNA and protein levels of ABCA1 in MDL group were significantly lower and the content of cholesterol was significantly higher than those in control group(P<0.05).The results in MDL+Ang-(1-7) group were between Ang-(1-7) group and control group.CONCLUSION: Ang-(1-7) inhibits the formation of foam cells by promoting the expression of ABCA1 and decreasing the content of cholesterol.MDL partly antagonizes the effect of Ang-(1-7) by inhibiting the adenylate cyclase and decreasing the content of cAMP.