Abstract | BACKGROUND: METHODS: NRK-49F cells stimulated with TGF-β1 were incubated with triptolide in various concentrations. ECM proteins, including collagen type III and fibronectin, were detected using the reverse transcription real-time PCR and ELISA methods. MAPK and Smad2/3 phosphorylation were measured with western blot. P38 and ERK 1/2 pathways were inhibited with the specific inhibitors, SB203580 and PD98059. The Smad2 signal was blocked with the siRNA method. RESULTS:
Triptolide inhibited ECM synthesis in TGF-β1-stimulated NRK-49F cells in a concentration-dependent manner. Triptolide enhanced TGF-β1-induced activation of the p38, ERK 1/2 signals, whereas it inhibited Smad2 activation. There was no crosstalk between the p38, ERK 1/2 and Smad2 pathways in NRK-49F cells. Inhibition of either the p38 or ERK 1/2 signals reduced ECM synthesis. Triptolide downregulated synthesis of fibronectin and collagen type III in TGF-β1-stimulated cells treated with SB203580 and/or PD98059. SB203580 and/or PD98059 significantly repressed synthesis of fibronectin and collagen type III in TGF-β1-stimulated cells treated with triptolide. Smad2 inhibition by siRNA significantly reduced ECM synthesis. However, ECM synthesis in NRK-49F cells transfected with Smad2 siRNA and treated by triptolide was increased compared with Smad2 siRNA-transfected cells. CONCLUSION: The effect of triptolide to suppress ECM synthesis by inhibiting Smad2 activation may surpass its stimulating effect on ECM synthesis by activation of p38 and ERK 1/2, leading to a total inhibition of ECM synthesis in TGF-β1-stimulated NRK-49F cells.
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Authors | Bin Zhu, Yong-jun Wang, Cai-feng Zhu, Yi Lin, Xiao-ling Zhu, Sheng Wei, Ying Lu, Xiao-xia Cheng |
Journal | Nephrology, dialysis, transplantation : official publication of the European Dialysis and Transplant Association - European Renal Association
(Nephrol Dial Transplant)
Vol. 25
Issue 10
Pg. 3180-91
(Oct 2010)
ISSN: 1460-2385 [Electronic] England |
PMID | 20466671
(Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
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Chemical References |
- Anti-Inflammatory Agents, Non-Steroidal
- Diterpenes
- Epoxy Compounds
- Extracellular Matrix Proteins
- Phenanthrenes
- Smad2 Protein
- Transforming Growth Factor beta1
- triptolide
- Extracellular Signal-Regulated MAP Kinases
- p38 Mitogen-Activated Protein Kinases
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Topics |
- Animals
- Anti-Inflammatory Agents, Non-Steroidal
(pharmacology)
- Cell Line
- Diterpenes
(pharmacology)
- Epoxy Compounds
(pharmacology)
- Extracellular Matrix Proteins
(biosynthesis)
- Extracellular Signal-Regulated MAP Kinases
(metabolism)
- Kidney
(drug effects, metabolism)
- MAP Kinase Signaling System
(drug effects)
- Phenanthrenes
(pharmacology)
- Phosphorylation
- Rats
- Smad2 Protein
(antagonists & inhibitors)
- Transforming Growth Factor beta1
(pharmacology)
- p38 Mitogen-Activated Protein Kinases
(metabolism)
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