Figure 8. Increased WNK1 abundance, SPAK/OSR1 activity, and aldosterone resistance in Nedd4-2^Pax8/LC1 KO mice.

(A) Left: Inducible double-transgenic renal tubule–specific Nedd4-2^Pax8/LC1 KO mice or single-transgenic Nedd4-2^Pax8 or Nedd4-2^LC1 controls were treated with doxycycline and administered a high-NaCl diet. Total kidney lysates (50 μg) were analyzed by immunoblotting with the indicated antibodies. In the WNK1 exon 12 blot, full-length L-WNK1 (L) and lower-MW species (brackets) are shown. Right: Quantification of immunoblotting data. n = 7 Nedd4-2^Pax8/LC1 mice and 7 controls for the WNK1, phospho-SPAK/OSR1, and NCC blots; n =6 Nedd4-2^Pax8/LC1 mice and 6 controls for the WNK4 blots; P values as indicated by Student’s t test. (B) Nedd4-2^Pax8/LC1 mice and single-transgenic controls were subjected to a 3-day infusion of aldosterone or DMSO vehicle via s.c. minipump. n = 5 Nedd4-2^Pax8/LC1 mice and 5 controls; P values as indicated, analyzed by 1-Way ANOVA Bonferroni test. For each data set, control values were set to a mean of 100%, and actin-normalized densitometry values from Nedd4-2^Pax/LC1 mice were expressed relative to the mean of the control. See also Supplemental Figure 6.