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Hypertonic sodium choloride and mannitol induces COX-2 via different signaling pathways in mouse cortical collecting duct M-1 cells

Cited 6 time in Web of Science Cited 8 time in Scopus
Authors
Lim, WonChung; Jung, JinSup; Surh, Youngjoon; Inoue, Hiroyasu; Lee, YoungJoo
Issue Date
2007-05
Citation
Life Sciences, Vol.80 No.22, pp.2085-2092
Keywords
kidney cortical collecting ducthypertonicitycyclooxygenase-2NF-kappa B
Abstract
The kidney cortical collecting duct is an important site for the maintenance of sodium balance. Previous studies have shown that, in renal medullary cells, hypertonic stress induces expression of cyclooxygenase-2 (COX-2) via NF-kappa B activation, but little is known about COX-2 expression in response to hypertonicity in the cortical collecting duct. Therefore, we examined the mechanism of hypertonic induction of COX-2 in M-1 cells derived from mouse cortical collecting duct. Induction of COX-2 protein was detected within 6 h of treatment with hypertonic sodium chloride. The treatment also increased COX-2 mRNA accumulation in a cycloheximide-independent manner, suggesting that ongoing protein synthesis is not required for COX-2 induction. Using reporter plasmids containing 0.2-, 0.3-, and 1.5-kb fragments of the COX-2 promoter, we found that hypertonic induction of COX-2 was due to an increase in promoter activity. The COX-2-inductive effect of hypertonicity was inhibited by SB203580, indicating that the effect is mediated by p38 MAPK. Since p38 MAPK can activate NF-kappa B, we made point mutations in the NF-kappa B binding site within the COX-2 promoter. The mutations did not block the induction of COX-2 promoter activity by hypertonic sodium chloride, and hypertonic sodium chloride failed to activate NF-kappa B binding site-driven reporter gene constructs. In contrast, hypertonic mannitol activated NF-kappa B, indicating that hypertonic mannitol and hypertonic sodium chloride activate COX-2 by different mechanisms. Thus, induction of COX-2 expression in M-1 cells by hypertonic sodium chloride does not involve activation of NF-kappa B. Furthermore, the signal transduction pathways that respond to hypertonic stress vary for different osmolytes in cortical collecting duct cells. (c) 2007 Elsevier Inc. All rights reserved.
ISSN
0024-3205
URI
https://hdl.handle.net/10371/172815
DOI
https://doi.org/10.1016/j.lfs.2007.03.014
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Graduate School of Convergence Science and Technology (융합과학기술대학원)Dept. of Molecular and Biopharmaceutical Sciences (분자의학 및 바이오제약학과)Journal Papers (저널논문_분자의학 및 바이오제약학과)
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