Noorman F, Barrett-Bergshoeff M M, Biessen E A, van de Bilt E, van Berkel T J, Rijken D C
Gaubius Laboratory, TNO Prevention and Health, Leiden, The Netherlands.
Hepatology. 1997 Nov;26(5):1303-10. doi: 10.1053/jhep.1997.v26.pm0009362376.
Recently, we developed a series of cluster mannosides that were able to inhibit tissue-type plasminogen activator (t-PA) binding to the isolated mannose receptor. The mannoside with the highest affinity was able to inhibit t-PA clearance by the liver in the rat. To test whether these mannosides would also be efficient inhibitors in humans, we studied the expression of the mannose receptor in the human liver and determined the efficacy of the mannosides to inhibit mannose receptor-mediated t-PA degradation by both rat and human cells. Immunohistochemistry indicates that, like the rat, human liver endothelial cells and human Kupffer cells do express the mannose receptor. The mannosides do inhibit mannose receptor-mediated t-PA binding, association, and degradation by isolated rat liver endothelial cells and t-PA association and degradation by cultured human macrophages at similar concentrations. The cluster mannoside with six mannose residues connected with a backbone of five lysine groups (M6L5) was, like unlabeled t-PA, able to inhibit 125I-t-PA degradation in the nmol/L range, while the mannoside M5L4 inhibited 125I-t-PA degradation in the micromol/L range. The concentrations of mannoside necessary to inhibit 125I-t-PA degradation in vitro were comparable with the concentrations necessary to inhibit mannose receptor-mediated 125I-t-PA clearance in vivo. We conclude that there is no species difference between rat and humans with respect to the distribution of the mannose receptor in the liver and the affinity of the cluster mannosides, establishing the relevance of the inhibition of mannose receptor-mediated t-PA clearance by M6L5 as observed in the rat, for the human situation.
最近，我们开发了一系列簇状甘露糖苷，它们能够抑制组织型纤溶酶原激活剂（t-PA）与分离出的甘露糖受体结合。亲和力最高的甘露糖苷能够抑制大鼠肝脏对t-PA的清除。为了测试这些甘露糖苷在人类中是否也是有效的抑制剂，我们研究了甘露糖受体在人肝脏中的表达，并确定了甘露糖苷对大鼠和人类细胞介导的甘露糖受体介导的t-PA降解的抑制效果。免疫组织化学表明，与大鼠一样，人肝脏内皮细胞和人库普弗细胞确实表达甘露糖受体。这些甘露糖苷确实能抑制甘露糖受体介导的t-PA结合、缔合以及分离的大鼠肝脏内皮细胞对t-PA的降解，以及培养的人巨噬细胞对t-PA的缔合和降解，且浓度相似。具有六个甘露糖残基并通过五个赖氨酸基团主链连接的簇状甘露糖苷（M6L5），与未标记的t-PA一样，能够在纳摩尔/升范围内抑制125I-t-PA的降解，而甘露糖苷M5L4在微摩尔/升范围内抑制125I-t-PA的降解。体外抑制125I-t-PA降解所需的甘露糖苷浓度与体内抑制甘露糖受体介导的125I-t-PA清除所需的浓度相当。我们得出结论，在肝脏中甘露糖受体的分布以及簇状甘露糖苷的亲和力方面，大鼠和人类之间没有物种差异，这确立了在大鼠中观察到的M6L5抑制甘露糖受体介导的t-PA清除与人类情况的相关性。
