Dexamethasone regulates AP-1 to repress TNF-alpha induced MCP-1 production in human glomerular endothelial cells.
BACKGROUND
Glomerular endothelial cells play a role in the pathogenesis of glomerulonephritis by producing chemotactic factors. We investigated the role of NF-kappa B and AP-1 in tumour necrosis factor alpha (TNF-alpha) induced monocyte chemoattractant protein 1 (MCP-1) production in cultured human glomerular endothelial cells (HGEC). We also examined whether or not these processes could be modified by glucocorticoid.


METHODS
MCP-1 protein and mRNA levels were measured by ELISA and northern blot. NF-kappa B and AP-1 binding activity were assessed by electrophoretic mobility shift assay. Cytosolic I kappa B alpha and nuclear p65 protein were evaluated by western blot. For specific inhibition of NF-kappa B or AP-1, we used a decoy oligodeoxynucleotide.


RESULTS
TNF-alpha (10 ng/ml) increased MCP-1 mRNA expression in HGEC and also the release of MCP-1 protein into culture media. These effects could be partially inhibited by dexamethasone (10 nM). TNF-alpha induced MCP-1 production appeared to be NF-kappa B and AP-1 interdependent, based on the following results. (i) TNF-alpha increased NF-kappa B and AP-1 binding activity. (ii) Both NF-kappa B decoy oligodeoxynucleotide and AP-1 decoy oligodeoxynucleotide partially suppressed TNF-alpha induced MCP-1 mRNA expression. On the other hand, dexamethasone decreased TNF-alpha induced DNA-binding activity of AP-1 without an effect on the DNA-binding activity of NF-kappa B, cytosolic I kappa B alpha degradation or p65 nuclear translocation.


CONCLUSIONS
These data demonstrate that while TNF-alpha induced MCP-1 production is mediated by the cooperative action of NF-kappa B and AP-1 in HGEC, dexamethasone represses TNF-alpha induced MCP-1 production via suppression of AP-1 binding activity.
Park
Su-Kil
SK
Department of Internal Medicine, Asan Medical Center, College of Medicine, University of Ulsan, Seoul, Korea. skpark@www.amc.seoul.kr
Yang
Won Seok
WS
Han
Nam Jung
NJ
Lee
Sang Koo
SK
Ahn
Hanjong
H
Lee
In Kyu
IK
Park
Joong Yeol
JY
Lee
Ki-Up
KU
Lee
Jae Dam
JD
D001483:Base Sequence; D015152:Blotting, Northern; D015153:Blotting, Western; D002478:Cells, Cultured; D018932:Chemokine CCL2 / Q000096:biosynthesis*; D003907:Dexamethasone / Q000494:pharmacology*; D015536:Down-Regulation; D004347:Drug Interactions; D004730:Endothelium, Vascular / Q000166:cytology*; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D007678:Kidney Glomerulus / Q000166:cytology; D008969:Molecular Sequence Data; D016328:NF-kappa B / Q000187:drug effects / Q000378:metabolism*; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000032:analysis; D012016:Reference Values; D012680:Sensitivity and Specificity; D018808:Transcription Factor AP-1 / Q000187:drug effects / Q000378:metabolism*; D014409:Tumor Necrosis Factor-alpha / Q000037:antagonists & inhibitors*
D018932:Chemokine CCL2; D016328:NF-kappa B; D012333:RNA, Messenger; D018808:Transcription Factor AP-1; D014409:Tumor Necrosis Factor-alpha; D003907:Dexamethasone