小凹蛋白在清道夫受体AI介导的巨噬细胞源性泡沫细胞形成过程中的作用

目的:研究小凹蛋白在清道夫受体AI介导的巨噬细胞源性泡沫细胞形成过程中的作用. 方法:用75 mg/L氧化型低密度脂蛋白(ox-LDL)与巨噬细胞共同孵育不同时间. 清道夫受体AI反义寡核苷酸、P38阻断剂SB202190预处理巨噬细胞,然后给予75 mg/L ox-LDL处理24 h. Western blot法检测清道夫受体AI和小凹蛋白的表达. 高效液相色谱法检测细胞内胆固醇的含量,油红O染色观察细胞内脂滴的形成情况. 结果:经75 mg/L ox-LDL处理巨噬细胞不同时间,ox-LDL呈时间依赖性促进清道夫受体AI的表达,而呈时间依赖性抑制小凹蛋白的表达. 用清道夫受体AI反义寡核苷酸抑制清道夫受体AI的表达,小凹蛋白的表达明显增加. 该组细胞内胆固醇含量为(119±7) mg/g,与ox-LDL处理组比较显著减少(P＜0.01),细胞内脂滴亦明显减少. P38MAPK抑制剂SB202190能明显抑制清道夫受体AI的表达,而增加小凹蛋白的表达. SB202190处理组细胞内胆固醇含量为(173±14) mg/g,与ox-LDL处理组比较显著减少(P＜0.01),细胞内脂滴亦明显减少. 结论:小凹蛋白与清道夫受体AI协同参与了ox-LDL诱导的巨噬细胞泡沫化的形成过程.

Role of caveolin-1 in SR-AI mediated formation of foam cells derived from macrophages

AIM: To investigate the role of caveolin-1 in scavenger receptor ai (SR-AI) mediated formation of macrophage-derived foam cells induced by oxidized low-density lipoprotein (ox-LDL). METHODS: RAW 264.7 macrophages were treated with 75 mg/L ox-LDL for different hours. Next, macrophages were pre-treated with SB202190 and SR-AI antisense oligonucleotides before 75 mg/L ox-LDL treatment for 24 h. Western blot analysis was used to detect protein expression. High performance liquid chromatography (HLPC) analysis was performed to determine the cellular cholesterol content. Oil red O staining was used to show the lipid droplets in foam cells. RESULTS: Western blot analysis showed that SR-AI expression increased with 75 mg/L ox-LDL treatment for 12, 24 and 48 h. 75 mg/L ox-LDL treatment for 6, 12, 24, 48 and 96 h decreased the expression of caveolin-1. When ox-LDL treatment was over 24 h, descended expression of caveolin-1 in macrophages was observed and lasted for 96 h. Pre-treatment of SB202190 and SR-AI antisense oligonucleotides decreased the expression of SR-AI and increased the expression of caveolin-1. Meanwhile, the cellular cholesterol content was also decreased (P<0.01 vs ox-LDL treatment groups). Oil red O staining showed that the SB202190 pre-treatment group and SR-AI antisense oligonucleotides group formed less lipid droplets than ox-LDL treatment group did. CONCLUSION: There appears a negative relationship between caveolin-1 and SR-AI during the accumulation of lipid-laden foam cells.