脂肪分化相关蛋白通过酰基辅酶A∶胆固醇酰基转移酶1促进巨噬细胞脂质蓄积

Adipophilin Accumlating Cellular Cholesterylester by Acyl-Coenzyme A:Cholesterol Acyltransferase in THP-1 Macrophages

目的观察高表达脂肪分化相关蛋白对酰基辅酶A∶胆固醇酰基转移酶1表达及脂质蓄积的影响。方法构建表达载体pcDNA3.1-HA-脂肪分化相关蛋白,使用THP-1巨噬细胞,通过瞬时转染使之高表达脂肪分化相关蛋白,依次用氧化型低密度脂蛋白和(或)丙泮尼地处理。逆转录聚合酶链反应和Western blot检测酰基辅酶A∶胆固醇酰基转移酶1及脂肪分化相关蛋白的表达,油红O染色和高效液相色谱检测细胞内脂质的蓄积。结果随着氧化型低密度脂蛋白浓度的增加,巨噬细胞脂肪分化相关蛋白及酰基辅酶A∶胆固醇酰基转移酶1表达明显增强,两者呈伴行关系。丙泮尼地能抑制酰基辅酶A∶胆固醇酰基转移酶1表达上调,且随处理时间延长,其表达逐渐减少,并且能减少细胞内脂滴生成。与对照组相比,瞬时转染pcDNA3.1-HA-脂肪分化相关蛋白能使脂肪分化相关蛋白表达明显升高。高表达脂肪分化相关蛋白的巨噬细胞能使酰基辅酶A∶胆固醇酰基转移酶1表达增加,促进细胞内胆固醇酯蓄积,并协同增强氧化型低密度脂蛋白的作用。加入丙泮尼地后,高表达脂肪分化相关蛋白的作用被减弱。结论高表达脂肪分化相关蛋白能上调THP-1巨噬细胞酰基辅酶A∶胆固醇酰基转移酶1表达,促进细胞内脂质蓄积。脂肪分化相关蛋白可能通过酰基辅酶A∶胆固醇酰基转移酶1促进细胞内胆固醇酯的蓄积。

Aim To investigate whether overexpression adipophilin induces acyl-coenzyme A：cbolesterol acyltransferase 1 （ACAT1） high expression and lipid accumulation in THP-1 macrophages. Methods TheTHP-1 cells were differentiated to macrophages through incubation with 160 nmol/L pborbol 12-myrlstate 13-acetate （PMA} for 24 h. To make overexpressed adipophilin macrophages, the pcDNA3, 1-HA-adi constructed was transfected to THP-1 macrophagas. Then, cells were incubated with or without oxidized low density lipoprotein （ox-LDL） and/or S-58035 for different time. ACAT1 and adipophilin expression were investigated with reverse transcription polymerase chain reaction （RT-PCR） and Western blot. Oil red O staining and high perfomance liquid chromatography （HPLC） were used to analyze the cellular cholesteryl ester accumulation. Results With the increasing incubated concentration of ox-LDL, both adipophilin and ACATI mRNA up-regulated obviously. The upregulated expression of ACATI induced by ox-LDL was inhibited by S-58035, and intracellular lipid droplets also decreased. Compared with control, transfecting pcDNA3, 1-HA-adi increased adipophilin protein level in THP-1 macrophages. Overexpresslon adipophilin cells significantly upregulated ACATI expression and promoted intraceJlular lipid accumulation. Ox-LDL syncrgized the effect of ACATI high expression. But the effect could be inhibited by S-58035. Conclusion Overexpression adipophilin can upregulate the ACATI expression in THP-1 macrophages, and increase cellular cbolesteryl ester. It suggested that adipophilin accumulated cellular cholesteryl ester by ACATI in THP-1 macrophages.