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

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

目的:构建THP-1源性泡沫细胞模型,探讨血管紧张素-(1-7)[Ang-(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。

AIM： To establish the THP-1-derived foam cell formation and to evaluate the effects of angiotensin-（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.