阻断Kv1.3和Kir2.1抑制人巨噬细胞源性泡沫细胞分化

目的:研究泡沫细胞分化过程中离子通道Kv1.3和Kir2.1的表达及作用。方法:用30mg/L氧化型低密度脂蛋白(ox-LDL)孵育巨噬细胞60h建立泡沫细胞模型。采用免疫细胞化学、RT-PCR和Western印迹检测人单核细胞源性巨噬细胞和泡沫细胞上Kv1.3和Kir2.1的表达。观察Kv1.3和Kir2.1特异性阻断剂rMargatoxin和BaCl2对巨噬细胞胆固醇代谢的影响。结果:ox-LDL(30mg/L)孵育巨噬细胞60h后,细胞内总胆固醇(TC),游离胆固醇(FC)及胆固醇酯(CE)显著增加,CE/TC从(14.4±6.8)%提高到(57.9±3.5)%(P<0.05);但Kv1.3和Kir2.1的表达水平在巨噬细胞组和泡沫细胞组无明显区别(P>0.05)。Kv1.3和Kir2.1分别被rMargatoxin(0.1,10nmol/L)和BaCl2(75,125μmol/L)阻断后,细胞内TC和CE水平显著降低,CE/TC低于50%(P<0.05)。结论:Kv1.3和Kir2.1对泡沫细胞的分化均起关键作用,特异性阻断后能够抑制人单核细胞源性巨噬细胞向泡沫细胞分化。

<FONT face=

OBJECTIVE: To investigate the expression of Kv1.3 and Kir2.1 during human monocyte-derived macrophages differentiation into foam cells and their function in foam cells formation. METHODS: The human macrophage-derived foam cells were obtained by incubating macrophages with ox-LDL (30 mg/L) for 60 h. The expression of Kv1.3 and Kir2.1 channels were examined by immunocytochemistry, RT-PCR and Western blot. Effects of channel blockers (rMargatoxin and BaCl2) on the cellular cholesterol metabolism were studied by measuring the cellular contents of total cholesterol (TC), free cholesterol (FC), and cholesterol ester (CE) in the presence or absence of the channel blockers. RESULTS: After incubating macrophages with 30 mg/L ox-LDL for 60 h, the cellular contents of TC, FC and CE were markedly increased and the ratio of CE/TC was raised from (14.4+/-6.8)% to (57.9+/-3.5)% (P<0.05), which indicated that the cells had differentiated into foam cells. The expression of Kv1.3 and Kir2.1 channels appeared no obvious difference when differentiating into foam cells (P>0.05); After being blocked specifically (rMargatoxin: 0.1, 10 nmol/L; BaC(12): 75, 125 micromol/L), the cellular contents of TC and CE were markedly reduced without exception and the ratios of CE/TC were all less than 50% (P<0.05). CONCLUSION: Both Kv1.3 and Kir2.1 channels play a critical role in differentiation of macrophages into foam cells and blockage of corresponding potassium channels would prevent the formation of the foam cells.