Protein kinase C activation by interleukin (IL)-1 limits IL-1-induced IL-6 synthesis in osteoblast-like cells: Involvement of phosphatidylcholine- specific phospholipase C

Osamu Kozawa, Atsushi Suzuki, Haruhiko Tokuda, Takehiro Kaida, Toshihiko Uematsu

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We investigated the regulatory mechanism of interleukin-6 (IL-6) synthesis induced by interleukin-1 (IL-1) in osteoblast-like MC3T3-E1 cells. IL-1 stimulated the secretion of IL-6 in a dose-dependent manner in the range between 0.1 and 100 ng/ml. Staurosporine and calphostin C, inhibitors of protein kinase C (PKC), significantly enhanced the IL-1-induced secretion of IL-6. The stimulative effect of IL-1 was markedly amplified in PKC down- regulated MC3T3-E1 cells. IL-1 produced diacylglycerol in MC3T3-E1 cells. IL- 1 had little effect on the formation of inositol phosphates and choline. On the contrary, IL-1 significantly stimulated the formation of phosphocholine dose-dependently. D-609, an inhibitor of phosphatidylcholine-specific phospholipase C, suppressed the IL-1-induced diacylglycerol production. The IL-1 -induced IL-6 secretion was significantly enhanced by D-609. These results indicate that IL-1 activates PKC via phosphatidylcholine-specific phospholipase C in osteoblast-like cells, and the PKC activation then limits IL-6 synthesis induced by IL-1 itself.

Original languageEnglish
Pages (from-to)103-111
Number of pages9
JournalJournal of Cellular Biochemistry
Issue number1
Publication statusPublished - 01-10-1997
Externally publishedYes


All Science Journal Classification (ASJC) codes

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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