氧化低密度脂蛋白负荷对巨噬细胞ABCA1及CD36表达的影响

Relationship between ox-LDL loading and expression levels of ABCA1 and CD36 in THP-1 macrophages

目的:探讨氧化低密度脂蛋白对THP-1巨噬细胞ATP结合盒转运体A1(ABCA1)及CD36表达之间的量效关系.方法:以不同浓度梯度(0,25,50,75,100mg/L)的氧化低密度脂蛋白(ox-LDL)与1640培养基联合培养THP-1巨噬细胞株,分别应用real-timePCR及激光共聚焦检测THP-1巨噬细胞在不同浓度梯度氧化低密度脂蛋白刺激时的AB-CA1与CD36 mRNA及蛋白质表达水平.结果:THP-1巨噬细胞CD36及ABCA1 mRNA及蛋白质在基础状态下表达水平均为最低.ox-LDL负荷可显著诱导ABCA1 mRNA及蛋白质的表达(均P>0.01),二者在培养基中ox-LDL浓度为50mg/L时表达最强,但随着刺激浓度的进一步增加其表达反而下调;CD36 mRNA及蛋白质的表达亦呈现与ABCA1类似的趋势,但CD36 mRNA表达组间差异缺乏显著性(P>0.05).结论:巨噬细胞ABCA1及CD36 mRNA及蛋白质表达与ox-LDL刺激浓度之间均呈现一种"抛物线"式量效关系.

AIM： To investigate the dose-effect relationship between oxidized low density lipoprotein （ox-LDL） stimulation and expression levels of ABCA1 and CD36 in THP-1 macrophages. METHODS： THP-1 cells were co-cultured with RPMI 1640 media and ox-LDL of 0, 25, 50, 75 and 100 mg/L under PMA stimulation. The macrophage-derived foam cells were determined with anti-CD68 antibody and Oil-red staining. The total RNA was extracted with Trizol reagent. The expression levels of mRNA and proteins for ATP-binding cassette transporter A1 （ ABCA1 ） and CD36 were determined with real-time PCR and laser confocal microscopy respectively. RESULTS： The expression levels of AB- CAI mRNA were lower at baseline, and increased significantly with ox-LDL stimulation, and reached highest levels at ox-LDL 50 mg/L （ P = 0. 000 ） , while CD36 mRNA expression was not significantly affected by ox-LDL loading （ P = 0.094 ）. However, the levels of ABCA1 and CD36 protein expression showed similar trend under ox-LDL loading, lower at baseline and reached highest at 50 mg/L ox-LDL stimulation, then decreased despite the higher concentration of ox-LDL （ P = 0.01 ）. CONCLUSION ： There is a parabela-like relationship between ox-LDL stimulation concentration and expression levels of proteins and/or mRNA of CD36 and ABCA1 in THP-1 macrophages.