FIGURE 1.

Increased NF-κB activity decreases AQP2 transcription in cultured collecting duct cells. A and B, cells were preincubated or not with 10^–10 m AVP for 24 h and then challenged for an additional 24 h with 0–1000 ng/ml LPS (A) or for 0–48 h with 10 ng/ml LPS (B) before RNA extraction. Real-time PCR was performed using primers specific for AQP2. Results are expressed relative to control values determined in the absence of LPS and in the absence (filled bars) or presence (open bars) of AVP. Bars are the mean ± S.E. from four independent experiments. *, p < 0.05. C, cells were immediately lysed or were preincubated with 5 × 10^–6 m actinomycin D for 30 min before 3 or 5 h of incubation in the absence or presence of 100 ng/ml LPS (in the continuous presence of actinomycin D) before RNA extraction. Real-time PCR was performed using primers specific for AQP2 (diamonds and squares) or IκBα (triangles and ×'s). Results are expressed as the percentage of control values for each gene determined in the absence of actinomycin D. Data are the mean ± S.E. from three independent experiments. D, cells were preincubated for 24 h with 10^–10 m AVP and then for an additional 3 or 24 h with 10 ng/ml LPS before protein extraction. Western blot analysis was performed on AQP2, and Na⁺, K⁺-ATPaseα1 subunit (NaKα) was used as a loading control. A representative image is shown. AQP2 abundance is expressed as the ratio of optical density values measured in the presence of LPS and that measured in the absence of LPS. Values are the mean ± S.E. from three independent experiments. *, p < 0.05.