Related Experiment Video
Updated: May 1, 2026
The Mouse Isolated Perfused Kidney Technique
Published on: November 17, 2016
WNK4 is the major WNK positively regulating NCC in the mouse kidney
Daiei Takahashi1, Takayasu Mori1, Naohiro Nomura1
1*Department of Nephrology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo, Tokyo 113-8519, Japan.
Abstract:
By analysing the pathogenesis of a hereditary hypertensive disease, PHAII (pseudohypoaldosteronism type II), we previously discovered that WNK (with-no-lysine kinase)-OSR1/SPAK (oxidative stress-responsive 1/Ste20-like proline/alanine-rich kinase) cascade regulates NCC (Na-Cl co-transporter) in the DCT (distal convoluted tubules) of the kidney. However, the role of WNK4 in the regulation of NCC remains controversial. To address this, we generated and analysed WNK4-/- mice. Although a moderate decrease in SPAK phosphorylation and a marked increase in WNK1 expression were evident in the kidneys of WNK4-/- mice, the amount of phosphorylated and total NCC decreased to almost undetectable levels, indicating that WNK4 is the major WNK positively regulating NCC, and that WNK1 cannot compensate for WNK4 deficiency in the DCT. Insulin- and low-potassium diet-induced NCC phosphorylation were abolished in WNK4-/- mice, establishing that both signals to NCC were mediated by WNK4. As shown previously, a high-salt diet decreases phosphorylated and total NCC in WNK4+/+ mice via AngII (angiotensin II) and aldosterone suppression. This was not ameliorated by WNK4 knock out, excluding the negative regulation of WNK4 on NCC postulated to be active in the absence of AngII stimulation. Thus, WNK4 is the major positive regulator of NCC in the kidneys.
Insights
WNK4 is the primary regulator of the Na-Cl co-transporter (NCC) in the kidney. WNK4 deficiency significantly reduces NCC levels, indicating it is essential for NCC function and hypertension regulation.
Area of Science:
- Nephrology
- Molecular Biology
- Endocrinology
Background:
- Pseudohypoaldosteronism type II (PHAII) involves hereditary hypertension.
- The WNK-OSR1/SPAK cascade regulates the Na-Cl co-transporter (NCC) in kidney distal convoluted tubules (DCT).
- The specific role of WNK4 in NCC regulation is debated.
Purpose of the Study:
- To elucidate the precise role of WNK4 in regulating NCC in the kidney.
- To determine if WNK1 can compensate for WNK4 deficiency in NCC regulation.
- To investigate WNK4's involvement in insulin- and diet-induced NCC phosphorylation.
Main Methods:
- Generation and analysis of WNK4 knockout (WNK4-/-) mice.
- Assessment of SPAK phosphorylation and WNK1 expression in kidney tissue.
- Quantification of phosphorylated and total NCC levels.
- Evaluation of NCC response to insulin, low-potassium, and high-salt diets.
Main Results:
- WNK4 deficiency led to near-undetectable levels of phosphorylated and total NCC.
- SPAK phosphorylation decreased moderately, while WNK1 expression increased in WNK4-/- mice.
- Insulin- and low-potassium diet-induced NCC phosphorylation were abolished in WNK4-/- mice.
- High-salt diet effects on NCC were not altered by WNK4 knockout.
Conclusions:
- WNK4 is the major positive regulator of NCC in the kidney.
- WNK1 cannot compensate for the loss of WNK4 in regulating NCC in DCT.
- WNK4 mediates insulin and low-potassium signaling to NCC.
- WNK4 does not exert negative regulation on NCC in the context of suppressed AngII stimulation.
Related Concept Videos
01:41Non-Canonical Wnt Signaling Pathways
01:10Nephrons
02:54Canonical Wnt Signaling Pathway
01:30Acute Kidney Injury IV: Diagnostic Studies and Prevention