Role of Reactive Oxygen Species and Mitogen-activated Protein Kinases in 2, 3, 7, 8-tetrachlorodibinzo-p-dioxin-induced Fibronectin Secretion by MDCK Cells.
- Author:
Mi Ra YU
1
;
Hunjoo HA
Author Information
1. Hyonam Kidney Laboratoy, Soon Chun Hyang University, Korea.
- Publication Type:Original Article
- Keywords:
Dioxin;
Tubular epithelial cells;
Fibronectin;
Reactive oxygen species;
Mitogen-activated protein kinases
- MeSH:
Antioxidants;
Blotting, Western;
Epithelial Cells;
Fibronectins*;
Fibrosis;
Kidney;
Madin Darby Canine Kidney Cells*;
Mitogen-Activated Protein Kinases*;
p38 Mitogen-Activated Protein Kinases;
Phosphorylation;
Phosphotransferases;
Protein Kinases;
Reactive Oxygen Species*;
Taurine;
Up-Regulation
- From:Korean Journal of Nephrology
2005;24(3):350-357
- CountryRepublic of Korea
- Language:Korean
-
Abstract:
BACKGROUND: 2, 3, 7, 8-tetrachlorodibenzo-p-dioxin (TCDD: dioxin) is a potent environmental toxicant that alters various cell function. Both reactive oxygen species (ROS) and mitogen-activated protein kinases (MAPK) mediate dioxin-induced cytotoxicity. Since dioxin was shown to increase renal cell fibronectin secretion in a dose-dependent manner and ROS and MAPK also play roles in fibronectin upregulation in renal cells, the present study examined whether ROS and/or MAPK activation play a role in dioxin-induced fibronectin upregulation in tubular epithelial cells. METHODS: Madin-Darby canine kidney (MDCK) cells were cultured with minimum essential medium (MEM) containing 10% fetal bovine serum. Growth arrested and synchronized MDCK cells by serum deprivation were stimulated with dioxin 1 nM in the presence or absence of extracellular signal-regulated protein kinase (ERK) inhibitor PD98059 50 microM, p38 MAPK inhibitor 100 nM, trolox 500 microM, or taurine 500 microM for up to 48 hours. Dichlorofulorescein (DCF)-sensitive cellular ROS was measured by FACScan and fibronectin in the media and cellular MAPK by a Western blot analysis. RESULTS: Dioxin 1 nM significantly increased cellular ROS and fibronectin in MDCK cells. Antioxidants, trolox and taurine, effectively inhibited dioxin-induced cellular ROS and fibronectin secretion. Dioxin increased phosphorylation of ERK at 5 minutes and P38 MAPK at 48 hours. Dioxin did not affect c-Jun NH2-terminal kinase (JNK) activation for up to 48 hours. Both PD98059 and p38 MAPK inhibitor suppressed dioxin-induced fibronectin secretion by MDCK cells. CONCLUSION: These data suggest that dioxin increases fibronectin secretion by renal distal tubular epithelial cells through ROS and MAPK (ERK and p38 MAPK) and this may lead to renal fibrosis.
