NF-κB activity is increased by hypertonicity in
mpkCCDcl4 cells. A, transfected cells expressing
NF-κB-driven luciferase were challenged with either isotonic
(Ctl, 300 mosmol/kg), hypertonic (NaCl, 500 mosmol/kg), or
urea-supplemented hyperosmotic (urea, 500 mosmol/kg) medium for 12 h or were
stimulated for 12 h with 100 μg/ml LPS in isotonic medium before measuring
luciferase activity. Bars are the mean ± S.E. from four
independent experiments. *, p < 0.05. B–D, cells
were challenged with isotonic medium (Ctl, 300 mosmol/kg) or with
either 100 ng/ml LPS (B), NaCl-supplemented hypertonic (400 or 500
mosmol/kg) (B) or urea-supplemented hyperosmotic (400 or 500
mosmol/kg) (C) medium for 2 or 24 h before RNA extraction. Real-time
PCR was performed using primers specific for TNFα, MCP-1, or
IκBα. Results are expressed relative to control values determined
for each gene after 2 h of incubation in isotonic medium. Bars are
the mean ± S.E. from five independent experiments. *, p <
0.05.