Kidney Week

Abstract: SA-PO1045

Generation and Analysis of KLHL2 Knockout Mice

Session Information

• Na+, K+, Cl-
  November 04, 2017 | Location: Hall H, Morial Convention Center
  Abstract Time: 10:00 AM - 10:00 AM

Category: Fluid, Electrolytes, and Acid-Base

• 703 Na+, K+, Cl- Basic

Authors

• Kasagi, Yuri, Tokyo Medical and Dental University, Bunkyo-ku, Tokyo, Japan

Yuri Kasagi,

• Takahashi, Daiei, Tokyo Medical and Dental University, Bunkyo-ku, Tokyo, Japan

Daiei Takahashi,

• Aida, Tomomi, Tokyo Medical and Dental University, Bunkyo-ku, Tokyo, Japan

Tomomi Aida,

• Nishida, Hidenori, Tokyo Medical and Dental University, Bunkyo-ku, Tokyo, Japan

Hidenori Nishida,

• Nomura, Naohiro, Tokyo Medical and Dental University, Bunkyo-ku, Tokyo, Japan

Naohiro Nomura,

• Zeniya, Moko, Tokyo Medical and Dental University, Bunkyo-ku, Tokyo, Japan

Moko Zeniya,

• Mori, Takayasu, Tokyo Medical and Dental University, Bunkyo-ku, Tokyo, Japan

Takayasu Mori,

• Sasaki, Emi, Tokyo Medical and Dental University, Bunkyo-ku, Tokyo, Japan

Emi Sasaki,

• Ando, Fumiaki, Tokyo Medical and Dental University, Bunkyo-ku, Tokyo, Japan

Fumiaki Ando,

• Rai, Tatemitsu, Tokyo Medical and Dental University, Bunkyo-ku, Tokyo, Japan

Tatemitsu Rai,

• Uchida, Shinichi, Tokyo Medical and Dental University, Bunkyo-ku, Tokyo, Japan

Shinichi Uchida,

• Sohara, Eisei, Tokyo Medical and Dental University, Bunkyo-ku, Tokyo, Japan

Eisei Sohara,

Background

Mutations in the with-no-lysine kinase 1 (WNK1), WNK4, Kelch-like 3 (KLHL3), and Cullin3 (CUL3) genes were identified as being responsible for hereditary hypertensive disease pseudohypoaldosteronism type II (PHAII). KLHL3/CUL3 ubiquitin ligase complex regulates degradation of WNK kinases via their degradtion. In PHAII, the loss of interaction between KLHL3 and WNK4 increases levels of WNKs because of impaired ubiquitination, leading to abnormal over-activation of the WNK-OSR1/SPAK-NCC cascade in the kidney’s distal convoluted tubules (DCT). KLHL2 is highly homologous to KLHL3, especially in kelch-repeat domain (WNK-binding domain). We previously reported KLHL2 ubiquitinated and degraded WNKs in vitro. However, the physiological role of KLHL2 in vivo is still unclear.

Methods

We generated KLHL2^-/- mice using CRISPR/cas9 system and evaluated the phenotype.

Results

KLHL2 expressed abundantly in the brain, stomach, and kidneys. However, we found that the expression of WNK4 was increased only in the KLHL2^-/- mice kidneys. KLHL2^-/- mice did not exhibit increased phosphorylation of the OSR1/SPAK-NCC cascade in the kidneys and PHAII-like phenotype. KLHL2 was predominantly expressed in the kidney medulla compared with the cortex. Accordingly, medullary WNK4 protein levels were significantly increased in the kidneys of KLHL2^-/- mice.

Conclusion

KLHL2 is indeed a physiological regulator of WNK4 in vivo; however, WNK protein levels in KLHL2-expressing tissues may not be solely governed by KLHL2, except in kidney medulla.

Funding

• Government Support - Non-U.S.