Bibliographic Details
| Title: |
(-)-Epigallocatechin Gallate Reduces Platelet-Derived Growth Factor-BB-Stimulated Interleukin-6 Synthesis in Osteoblasts: Suppression of SAPK/JNK. |
| Authors: |
Takai, Shinji1, Matsushima-Nishiwaki, Rie1, Adachi, Seiji1, Natsume, Hideo1,2, Minamitani, Chiho1,2, Mizutani, Jun2, Otsuka, Takanobu2, Tokuda, Haruhiko1,3, Kozawa, Osamu1 okozawa@gifu-u.ac.jp |
| Superior Title: |
Mediators of Inflammation. 2008, Vol. 2008 Issue 2, Special section p1-8. 8p. 5 Graphs. |
| Subject Terms: |
*EPIGALLOCATECHIN gallate, *FLAVONOIDS, *PLATELET-derived growth factor, *INTERLEUKIN-6, *MITOGEN-activated protein kinases, *JNK mitogen-activated protein kinases |
| Abstract: |
We previously showed that the mitogen-activated protein (MAP) kinase superfamily, p44/p42 MAP kinase, p38 MAP kinase, and stress-activated protein kinase (SAPK)/c-Jun N-terminal (JNK), positively plays a part in the platelet-derived growth factor-BB-(PDGF-BB-) stimulated synthesis of interleukin-6 (IL-6), a potent bone resorptive agent, in osteoblast-like MC3T3-E1 cells while Akt and pT0 S6 kinase negatively regulates the synthesis. In the present study, we investigated whether (-)-epigallocatechin gallate (EGCG), one of the major green tea flavonoids, affects the synthesis of IL-6 in these cells and the mechanism. EGCG significantly reduced the IL-6 synthesis and IL-6 mRNA expression stimulated by PDGF-BB, EGCG reduced the PDGF-BB-stimulated IL-6 synthesis also in primary-cultured osteoblasts. EGCG had no effect on the levels of osteocalcin and osteoprotegerin in MC3T3-E1 cells. The PDGF-BB-induced autophosphorylation of PDGF receptor β was not suppressed by EGCG. The PDGF-BB-induced phosphorylation of p44/p42 MAP kinase and p38 MAP kinase was not affected by EGCG. On the other hand, EGCG markedly suppressed the PDGF-BB-induced phosphorylation of SAPK/JNK. Finally, the PDGF- BB-induced phosphorylation of Akt and p70 S6 kinase was not affected by EGCG. These results strongly suggest that EGCG inhibits the PDGF-BB-stimulated synthesis of IL-6 via suppression of SAPK/JNK pathway in osteoblasts. [ABSTRACT FROM AUTHOR] |
|
Copyright of Mediators of Inflammation is the property of Hindawi Limited and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.) |
| Database: |
Academic Search Premier |