Lee M E, Rhee K J, Nham S U
Department of Biology, Kangwon National University, Chunchon, Korea.
Mol Cells. 1999 Feb 28;9(1):7-13.
Fibrin derived from fibrinogen after thrombin cleavage plays an essential role in forming blood clots. Fibrin as well as fibrinogen is also involved in the induction of platelet aggregation, leukocyte cell adhesion and phagocytosis. An additional biological role of fibrin and fibrinogen is presented in this study. One of the proteolytic peptides of fibrin/fibrinogen, fragment E, and not fragment D, was able to stimulate rat peritoneal macrophages to express interleukin-6 (IL-6). The stimulation of fibrin/fibrinogen fragment E on macrophages appeared to work in a dose- and time-dependent manner. Adherent fibrin fragment E was able to stimulate IL-6 expression as well as IL-6 protein production. The effect of fibrin fragment E was inhibited by the addition of an excess amount of GPRP tetrapeptide, but not by GHRP, which are the amino acids derived from the amino terminus of fibrin alpha and beta chains, respectively. These results suggest that fibrin as well as fibrinogen function as a stimulator to macrophages, and leukocyte integrin p150,95 (CD11c/ CD18), not Mac-I (CD11b/CD18), is involved in mediating fibrin stimulatory activity in macrophages.
凝血酶切割纤维蛋白原后产生的纤维蛋白在形成血凝块过程中起关键作用。纤维蛋白以及纤维蛋白原还参与诱导血小板聚集、白细胞细胞黏附和吞噬作用。本研究展示了纤维蛋白和纤维蛋白原的另一种生物学作用。纤维蛋白/纤维蛋白原的一种蛋白水解肽片段E，而非片段D，能够刺激大鼠腹腔巨噬细胞表达白细胞介素-6（IL-6）。纤维蛋白/纤维蛋白原片段E对巨噬细胞的刺激作用似乎呈剂量和时间依赖性。黏附的纤维蛋白片段E能够刺激IL-6表达以及IL-6蛋白产生。添加过量的GPRP四肽可抑制纤维蛋白片段E的作用，但添加分别源自纤维蛋白α链和β链氨基末端的氨基酸GHRP则无此作用。这些结果表明，纤维蛋白以及纤维蛋白原可作为巨噬细胞的刺激物，且白细胞整合素p150,95（CD11c/CD18）而非Mac-I（CD11b/CD18）参与介导纤维蛋白对巨噬细胞的刺激活性。
