脂蛋白(a)的赖氨酸结合异质性对人动脉SMC增殖的影响

为探讨脂蛋白 ( a) Lp( a) ]的赖氨酸结合功能在致动脉粥样硬化中的作用 ,利用短时超速离心结合凝胶层析分离纯化 Lp( a) ,以 Lysine- Sepharose4B亲和层析分离出能与柱结合的 Lp( a)Lys+ 和不能与柱结合的 Lp( a) Lys-.采用 MTT比色法、流式细胞仪分析细胞增殖状况 ,同时以ELISA法检测细胞培养液中转化生长因子β( TGF-β)的活化水平 ,观察了两种 Lp( a)对培养的人动脉平滑肌细胞 ( SMC)增殖的影响 .结果表明 :Lp( a)、Lp( a) Lys+ 较 Lp( a) Lys-能有效地促进SMC增殖 ,刺激细胞从 G0 /G1期进入 S和 G2 /M期 ,并显著降低培养液中 TGF- β活化量 .提示 :Lp( a) Lys+ 可能是 Lp( a)促人 SMC增殖的主要组分 ,其机制可能与干扰纤溶酶原活化 ,从而抑制TGF-β活化有关 .

Effects of Lysine-binding Heterogenous Lipoprotein(a) on the Proliferation of Human Arterial Smooth Muscle Cells

The effects of lysine binding heterogenous lipoprotein(a)Lp(a)] on proliferation of human arterial smooth muscle cells(SMCs)and its mechanism of action were investigated.Lp(a) was isolated and purified from human plasma by ultracentrifugation and gel permeation chromatography,followed by Lysine Sepharose 4B affinity chromatography,which was separated into Lp(a)Lys + and Lp(a)Lys -。The proliferation of SMCs was determined by flow cytometry and MTT colorimetry.ELISA assay was used to detect the active form of transforming growth factor β(TGF β).The results showed that Lp(a),Lp(a)Lys + effectively promoted proliferation of human SMCs,stimulated cells in the G 1/G 0 phase of cell cyle to S and G 2/M phase ,and reduced significantly the amounts of active TGF β in culture,however,Lp(a)Lys - had no effect.The results suggest that Lp(a)Lys + might be the major source of Lp(a) in stimulating the proliferation of SMCs and its mechanism may be involved in inhibition of plasminogen activation and consequently the activation of latent TGF β。