可溶性Klotho蛋白抑制THP-1源性泡沫细胞形成

目的:探讨可溶性Klotho(KL)蛋白对THP-1源性泡沫细胞形成的影响。方法:THP-1单核细胞与160 nmol/L佛波酯孵育48 h后,诱导分化为THP-1源性巨噬细胞,给予THP-1源性巨噬细胞不同浓度(25、50、100和200μg/L)的可溶性KL蛋白预处理后,再由氧化型低密度脂蛋白(ox-LDL)诱导其转变为泡沫细胞。油红O染色观察细胞内脂滴形成情况,通过液体闪烁计数法测定THP-1源性泡沫细胞内胆固醇流出情况,酶荧光法检测细胞内游离胆固醇及胆固醇酯的含量,并分别用Western blot法及RT-qPCR法检测酰基辅酶A:胆固醇酰基转移酶1(ACAT1)和ATP结合盒转运体A1(ABCA1)的蛋白及mRNA表达。结果:可溶性KL蛋白能增加THP-1源性巨噬细胞内胆固醇流出,抑制THP-1源性泡沫细胞形成,且可溶性KL蛋白呈一定浓度依赖性地抑制ox-LDL诱导的泡沫细胞形成过程中ACAT1表达的上调和ABCA1表达的下调(P<0.05)。结论:可溶性KL蛋白能够抑制THP-1源性泡沫细胞形成,其机制可能与靶向调控细胞内ACAT1和ABCA1的表达有关。

Soluble Klotho protein suppresses THP-1-derived foam cell formation

AIM:To investigate the role of soluble Klotho protein in THP-1-derived foam cell formation.METHODS:THP-1 monocytes were induced into macrophages by treatment with 160 nmol/L phorbol myristate acetate for 48 h,and then were divided into 6 groups:negative control group(THP-1-derived macrophages),positive control group[THP-1-derived foam cells induced by oxidized low-density lipoprotein(ox-LDL)for 48 h],and 25,50,100 and200 μg/L soluble Klotho protein groups(THP-1-derived macrophages pretreated with soluble Klotho protein at the indicated concentraions for 2 h and then induced by ox-LDL for 48 h).Lipid droplets in cytoplasm were observed by oil red O staining.The cholesterol outflow rate was detected by scintillation counting technique.The content of intracellular total cholesterol,free cholesterol and cholesterol ester was detected by enzyme fluorescence analysis.The expression of acyl-coenzyme A:cholesterol acyltransferase 1(ACAT1)and ATP-binding cassette transporter A1(ABCA1)at mRNA and protein levels was determined by RT-qPCR and Western blot,respectively.RESULTS:Oil red O staining and lipid mass quantification showed that THP-1-derived foam cell formation was dose-dependently suppressed by soluble Klotho protein.The cholesterol efflux rate of THP-1-derived foam cells was increased by soluble Klotho protein in a dose-dependent manner(P<0.05).In addition,soluble Klotho protein decreased the expression of ACAT1 and increased the expression of ABCA1 in a dose-dependent manner(P<0.05).CONCLUSION:The soluble Klotho protein inhibits THP-1-derived foam cell formation in a dose-dependent manner by down-regulating the expression of ACAT1 and up-regulating the expression of ABCA1.