Basu S K, Goldstein J L, Brown M S
Science. 1983 Feb 18;219(4586):871-3. doi: 10.1126/science.6823554.
Cholesterol-loaded macrophages secrete cholesterol and apolipoprotein E. The current studies show that this secretion occurs by two independent pathways. In the absence of serum, the cells secrete apolipoprotein E, but not cholesterol. In the presence of monensin (an inhibitor of protein secretion), the cells secrete cholesterol, but little apolipoprotein E. After secretion, apolipoprotein E and cholesterol associate with high-density lipoprotein to form a particle that can deliver cholesterol to the liver by receptor-mediated endocytosis. We conclude that apolipoprotein E does not function to remove cholesterol from macrophages but rather to participate in "reverse cholesterol transport."
胆固醇负载的巨噬细胞分泌胆固醇和载脂蛋白E。目前的研究表明，这种分泌通过两条独立的途径发生。在无血清的情况下，细胞分泌载脂蛋白E，但不分泌胆固醇。在莫能菌素（一种蛋白质分泌抑制剂）存在的情况下，细胞分泌胆固醇，但很少分泌载脂蛋白E。分泌后，载脂蛋白E和胆固醇与高密度脂蛋白结合形成一种颗粒，该颗粒可通过受体介导的内吞作用将胆固醇输送到肝脏。我们得出结论，载脂蛋白E的功能不是从巨噬细胞中清除胆固醇，而是参与“胆固醇逆向转运”。
