丹酚酸B在巨噬细胞胆固醇外排中的作用

Salvianolic acid B promotes cholesterol efflux from macrophages

目的考察丹酚酸B(SAB)对巨噬细胞胆固醇外排的影响。方法分别采用巨噬细胞RAW264.7和PMA诱导的THP-1细胞,利用流式细胞仪检测丹酚酸B对已摄取DiI-acLDL的细胞外排脂质作用的影响,对RAW264.7细胞表面ABCA1蛋白表达水平的影响。采用ABCA1的抑制剂DIDS及小分子干扰RNA的方法检测ABCA1在丹酚酸B诱导的促进脂质外排过程中的作用。进而利用靶向CD36的小分子干扰RNA,通过抑制CD36的表达,检测CD36在丹酚酸B促进载脂巨噬细胞脂质外排过程中的作用。结果采用DiI荧光标记的脂质检测巨噬细胞对脂质的外排作用,结果显示SAB显著增加了荷脂细胞对DiI-acLDL的外排作用。对脂代谢相关转运蛋白表达的检测结果显示,在荷脂的RAW264.7细胞中,SAB能够以一定剂量依赖的方式增加细胞表面ABCA1蛋白水平的表达。进一步研究显示,上述SAB促进外排的作用可被ABCA1的抑制剂或者siRNA的作用消除,确证了ABCA1在SAB介导的脂质外排过程中的重要作用。同样利用CD36小分子干扰RNA将CD36表达抑制后,SAB促进外排的作用消失,说明SAB介导的细胞脂质的外排作用同样依赖于CD36。结论丹酚酸B通过上调ABCA1的表达,促进巨噬细胞胆固醇或脂质的外排,且该作用依赖于ABCA1及CD36,为SAB抗动脉粥样硬化作用新机制的研究提供了重要依据。

Objective To investigate the effect of salvianolic acid B （SAB） on cholesterol effiux from macrophages. Methods The effect of SAB on cholesterol effiux from RAW 264.7 cells and PMA-induced THP-1 cells loaded with DiI-acLDL was detected by flow cytometry analysis. The expression of ABCA1 in RAW 264.7 cells regulated by SAB was detected using flow cytometry. Then ABCA1 inhibitor DIDS and ABCA1 siRNA were applied to investigate the role of ABCA1 in SAB-mediated cholesterol effiux. The role of CD36 in this process was also detected by CD36 siRNA interference. Results Macrophages loaded with DiI-acLDL were used and the DiI fluorescence in the macrophages or medium was detected respectively. The results showed that SAB significantly promoted cholesterol effiux from DiI-acLDL-loaded macrophages. The expression of transporters in lipid metabolism was also detected. SAB upregulated ABCA1 protein level in lipid-rich RAW 264.7 cells in a dose-dependent manner. Further investigation using ABCA1 inhibitor or siRNA revealed that ABCA1 played an important role in SAB mediated cholesterol effiux. Similar role of CD36 in this process was testified by attenuating CD36 mRNA level, implicating that the cholesterol effiux mediated by SAB was dependent on CD36. Conclusion SAB promotes cholesterol efflux from macrophages through upregulating ABCA1 expression, which is dependent on ABCA1 and CD36, providing an important basis for the investigation of novel anti-atherosclerosis mechanisms of SAB.