Igaz P, Tóth S, Rose-John S, Madurka I, Fejér G, Szalai C, Falus A
Department of Genetics, Cell- and Immunobiology, Semmelweis University Medical School, Budapest, Hungary.
Cytokine. 1998 Aug;10(8):620-6. doi: 10.1006/cyto.1997.0330.
Interleukin 6 (IL-6) belongs to a family of cytokines using receptors sharing a common signal-transducing chain, gp130 and containing a specific ligand-binding chain (IL-6R alpha). It was shown that both the membrane-bound and the soluble form (sIL-6R) of this ligand specific receptor chain occurs naturally. The soluble form of IL-6 receptor was found to be able to associate with the membrane-bound gp130 and to generate active IL-6 receptor complex capable of inducing signal transduction. This study on a human hepatoma cell line and primary rat hepatocytes examined how the effectiveness of IL-6 is modified by the presence of soluble IL-6 receptor and whether the sIL-6R in the absence of IL-6 acts on hepatocytes. The authors studied the gene expression of junB, a member of the Jun family of transcription factors, and the production of fibrinogen in response to IL-6 and sIL-6R. The data show that in hepatic cells, endogeneously expressing IL-6R, the IL-6 induced junB and fibrinogen expression is inhibited by the presence of sIL-6R. In addition we found that sIL-6R alone (in the absence of IL-6) induced junB mRNA expression, but had no effect on fibrinogen production.
白细胞介素6（IL-6）属于一类细胞因子家族，其受体共享一条共同的信号转导链gp130，并包含一条特定的配体结合链（IL-6Rα）。研究表明，这种配体特异性受体链的膜结合形式和可溶性形式（sIL-6R）均天然存在。发现IL-6受体的可溶性形式能够与膜结合的gp130结合，并生成能够诱导信号转导的活性IL-6受体复合物。这项针对人肝癌细胞系和原代大鼠肝细胞的研究，考察了可溶性IL-6受体的存在如何改变IL-6的效力，以及在没有IL-6的情况下sIL-6R是否作用于肝细胞。作者研究了转录因子Jun家族成员junB的基因表达，以及对IL-6和sIL-6R的反应中纤维蛋白原的产生。数据表明，在内源性表达IL-6R的肝细胞中，sIL-6R的存在会抑制IL-6诱导的junB和纤维蛋白原表达。此外，我们发现单独的sIL-6R（在没有IL-6的情况下）可诱导junB mRNA表达，但对纤维蛋白原的产生没有影响。
