Soluble interleukin 6 (IL-6) receptor influences the expression of the protooncogene junB and the production of fibrinogen in the HepG2 human hepatoma cell line and primary rat hepatocytes.
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.
Department of Genetics, Cell- and Immunobiology, Semmelweis University Medical School, Budapest, Hungary.
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P
Igaz
S
S
Tóth
S
S
Rose-John
I
I
Madurka
G
G
Fejér
C
C
Szalai
A
A
Falus
D000818:Animals; D006528:Carcinoma, Hepatocellular; D002478:Cells, Cultured; D005340:Fibrinogen / Q000096:biosynthesis*; D005786:Gene Expression Regulation; D006801:Humans; D008099:Liver / Q000166:cytology / Q000378:metabolism*; D016133:Polymerase Chain Reaction / Q000379:methods; D016755:Proto-Oncogene Proteins c-jun / Q000096:biosynthesis* / Q000235:genetics; D012333:RNA, Messenger; D051381:Rats; D019947:Receptors, Interleukin-6 / Q000378:metabolism*; D012995:Solubility; D014407:Tumor Cells, Cultured
D016755:Proto-Oncogene Proteins c-jun; D012333:RNA, Messenger; D019947:Receptors, Interleukin-6; D005340:Fibrinogen