人巨噬细胞源性泡沫细胞分化中Kir2.1通道的表达

目的 Kir2.1通道是控制骨髓源性巨噬细胞增殖、活化和凋亡的重要离子通道之一,并且还参与细胞分化。本研究观察Kir2.1通道mRNA及蛋白在人单核细胞源性巨噬细胞向泡沫细胞分化过程中的表达。方法 采用密度梯度离心加贴壁黏附法,从男性健康志愿者的外周血中分离单核细胞,经5d培养后分化为巨噬细胞。在建立人巨噬细胞源性泡沫细胞模型的基础上,采用RT-PCR,蛋白质印迹及免疫细胞化学方法研究Kir2.1通道的表达。结果 将巨噬细胞同30mg/L氧化修饰低密度脂蛋白(OxLDL)于37℃孵育60h后,细胞体积增大,并有许多红色的脂质颗粒沉积于细胞质内,细胞内的总胆固醇(TC)、游离胆固醇(FC)及胆固醇酯(CE)的含量分别从(54.79±28.304)mg/g、(47.968±26.787)mg/g和(6.822±3.437)mg/g增加至(229.775±57.453)mg/g、(96.241±24.003)mg/g和(133.535±36.292)mg/g,CE/TC从(14.437±6.781)%提高到(57.946±3.507)%(n=7,P<0.05)]。但是,Kir2.1通道mRNA的扩增量在巨噬细胞和分化的泡沫细胞之间无显著差异(59.074±10.566)%vs(46.98±12.527)%,n=5,P＞0.05];同样,Kir2.1通道蛋白在巨噬细胞和分化的泡沫细胞之间亦无显著差异(60.527±18.621)%vs(50.243±11.583)%,n=6,P＞0.05]。结论 人单核细胞源性巨噬细胞同30mg/LOxLDL孵育60h后可分化为泡沫细胞,但Kir2.1通道的表达无明显改变。

Expression of Kir2.1 channel during differentiation of human macrophages into foam cells

Objective Detected in non-transformed bone marrow-derived macrophages (BMDM) and identified as one of the key channels in modulating macrophage proliferation, activation and apoptosis, Kir2.1 channel is also characterized to play a crucial role in cell differentiation. The purpose of this study was to investigate the expression of Kir2.1 channel mRNA and protein during human monocyte-derived macrophage differentiation into foam cells. Methods Human peripheral blood monocytes were isolated from healthy male volunteers by density gradient centrifugation and then by adherence method. The macrophages identified as a homogeneous population of adherent cells were obtained after 5 days of culture. Expression of Kir2.1 channel during human macrophage differentiation into foam cells was investigated by RT-PCR, Western blotting and immunocytochemistry, respectively. Results After incubation of the macrophages with 30 mg/L OxLDL at 37℃ for 60 h, the cells were obviously enlarged in size and numerous red lipid granules observed under optical microscope. The cellular contents of the total cholesterol (TC), free cholesterol (FC) and cholesterol ester (CE) were markedly increased from 54.79±28.304 mg/g, 47.968±26.787 mg/g and 6.822±3.437 mg/g to 229.775±57.453 mg/g, 96.241±24.003 mg/g and 133.535±36.292mg/g, respectively; the CE/TC ratio rose from (14.437±6.781)% to (57.946±3.507) % (n=7, P＜0.05), suggesting the phenotype of foam cells. However, there was no significant difference in the relative expression of Kir2.1 channel mRNA between the macrophages and foam cells (59.074±10.566)% vs (46.98±12.527)%, n=5, P＞0.05], nor was there significant difference in the relative expression of Kir2.1 channel protein between them (60.527±18.621)% vs (50.243±11.583)%, n=6, P＞0.05].Conclusion Incubation of human monocyte-derived macrophages with 30 mg/L OxLDL for 60 h induces the differentiation of the cells into foam cells, but the expression of Kir2.1 channel does not change obviously.