外源性ApoE_3对U937细胞摄取VLDL两亚组分的影响

The Effect of Exogenous ApoE3 Gene Expression on U937 Cells Upta- king the Two Subfractions of VLDL

目的研究巨噬细胞(Mφ)分泌的载脂蛋白E(ApoE)在贫含ApoE的极低密度脂蛋白(ApoE-poor-VLDL)导致Mφ泡沫化中的作用。方法建立稳定表达ApoE3的U937细胞系,该细胞系分别与FOTP标记的不同浓度的ApoE-poor-VLDL及ApoE-rich-VLDL孵育,以细胞内荧光强度/蛋白浓度为观测指标,观察外源性ApoE3的表达对U937细胞摄取VLDL两亚组分的影响。结果 外源性ApoE3的表达显著促进U937细胞摄取ApoE-poor-VLDL(p<0.05),而对ApoE-rich-VLDL的摄取无显著影响(P>0.05)。结论Mφ分泌的ApoE可能参与到ApoE-poor-VLDL中,提高其中ApoE的含量,从而介导Mφ摄取ApoE-poor-VLDL,是ApoE-poor-VLDL导致Mφ内脂质堆积的主要原因。

Objective To investigate the role of apolipoproteinE secreted by macrophages in the formation of foam cells induced by ApoE-poor-VLDL. Methods The recombinant containing human ApoE3 gene was stably transfected into U937 cells by lipofectin. ApoE-poor-VLDL and ApoE-rich-VLDL were labeled by FITC. Transfected and untransfected U937 were coincubated with the two subfractions of VLDL at various concentrations respectively. The uptake of VLDL was demonstrated by FITC/protein concentration. Results The expression of the exogenous ApoE3 had no significant effect on the internalization of ApoE-rich-VLDL (P >0. 05) , but significantly enhanced U937 cells' to uptake of ApoE-poor-VLDL (P < 0. 05) . Conclusion ApoE3 secreted by U937 could incorporate into ApoE-poor-VLDL. This can accelerate cells' uptake of ApoE-poor-VLDL, resulting in lipid accumulation in the cells.