天然及氧化型脂蛋白(a)与巨噬细胞表面结合

为探讨脂蛋白 (a)及氧化型脂蛋白 (a)在巨噬细胞上的结合和降解途径 ,将生物素标记的脂蛋白与小鼠腹腔巨噬细胞进行结合和竞争性结合试验。结果发现 ,脂蛋白 (a)能以一定的亲和力、可饱和性地与巨噬细胞表面结合 ;低密度脂蛋白对其结合无明显抑制作用 ,而氧化型低密度脂蛋白、氧化型脂蛋白 (a)均能不同程度地抑制这种结合。脂蛋白 (a)经氧化修饰后 ,与巨噬细胞的结合量显著增加。脂蛋白 (a)、低密度脂蛋白不能有效竞争氧化型脂蛋白 (a)的结合 ,而氧化型脂蛋白 (a)和氧化型低密度脂蛋白为有效的竞争性抑制剂。提示脂蛋白 (a)主要经清道夫受体与巨噬细胞表面结合 ;氧化型脂蛋白 (a)除经清道夫受体介导外 ,可能还通过其它特异性受体与巨噬细胞表面结合。

Binding of Lipoprotein(a) and Oxidized Lipoprotein(a) by the Mouse Peritoneal Macrophage

Aim To clarify the binding and degradative pathwa y of lipoprotein(a) and oxidized lipoprotein(a). Methods The binding and the competitive binding assays about Lp(a) and oxidized Lp(a) with the mouse peritoneal macrophage were performed. Results Lp(a) was bound with affinity, saturation to macro phage surface. LDL was minimal potency in competing with Lp(a) for the binding site, in contrast, ox LDL and ox Lp(a) were efficient competitor for the bindi ng of Lp(a). Oxidative modification of Lp(a) by Cu 2 increased markedly i ts binding to macrophages. Ox Lp(a) and ox LDL were excellent competitor for the binding of ox Lp(a) to macrophages. Conclusions The binding of Lp(a) with macrophages by the scavenger receptor medi ated pathway; Scavenger receptor provided a significant route for the metabolism of ox Lp(a), perhaps, any other special receptor also mediated the binding of ox Lp(a) to macrophages.