Abstract: SA-PO1039

Decreased Protein Expression of KLHL3 Is Involved in the Pathogenesis of PHAII Caused by CUL3 Mutation In Vivo

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

  • Yoshida, Sayaka, Tokyo Medical and Dental University, Bunkyo-ku, Tokyo, Japan
  • Uchida, Shinichi, Tokyo Medical and Dental University, Bunkyo-ku, Tokyo, Japan
  • Sohara, Eisei, Tokyo Medical and Dental University, Bunkyo-ku, Tokyo, Japan
  • Araki, Yuya, Tokyo Medical and Dental University, Bunkyo-ku, Tokyo, Japan
  • Mori, Takayasu, Tokyo Medical and Dental University, Bunkyo-ku, Tokyo, Japan
  • Sasaki, Emi, Tokyo Medical and Dental University, Bunkyo-ku, Tokyo, Japan
  • Kasagi, Yuri, Tokyo Medical and Dental University, Bunkyo-ku, Tokyo, Japan
  • Isobe, Kiyoshi, Tokyo Medical and Dental University, Bunkyo-ku, Tokyo, Japan
  • Susa, Koichiro, Tokyo Medical and Dental University, Bunkyo-ku, Tokyo, Japan
  • Inoue, Yuichi, Tokyo Medical and Dental University, Bunkyo-ku, Tokyo, Japan
  • Rai, Tatemitsu, Tokyo Medical and Dental University, Bunkyo-ku, Tokyo, Japan
Background

Pseudohypoaldosteronism type II (PHAII) is a hereditary hypertensive disease. PHAII is caused by mutations in four genes: WNK1, WNK4, KLHL3 and Cullin3 (Cul3). Recently it was revealed that Cul3-KLHL3 E3 ligase complex ubiquitinate WNK1 and WNK4, leading to their degradation, and that one of the common pathogenesis of PHAII is the defective degradation of WNKs by Cul3-KLHL3 E3 ligase complex. PHAII-causing Cul3 mutations result in the skipping of exon 9, leading to a CUL3 protein with a 57-amino acid deletion(Δ403-459). However, the pathogenesis of PHAII caused by CUL3Δ403–459 in vivo is still unclear.

Methods

We generated and analyzed CUL3WT/Δ403-459 PHAII model mice.

Results

CUL3 WT / Δ 403-459 mice were successfully generated, and they exhibited hyperkalemia, metabolic acidosis and hypertension, indicating that they are good mouse model of PHAII. Protein levels of WNK kinases were increased, resulting in increased phosphorylation of OSR1, SPAK, and NCC, the downstream components of the WNK signal. In CUL3WT/Δ403-459 mice, the abundance of KLHL3 protein was decreased in kidney and brain. On the other hand, the protein levels of the other KLHL family proteins, KLHL2 and Keap1, which also form ubiquitin ligase complexes with CUL3, were comparable between CUL3WT/WT and CUL3WT/Δ403-459.

Conclusion

In CUL3 WT / Δ 403-459 mice, expression levels of KLHL3 were decreased. Considering that heterogygous knockout of CUL3 expression alone in mice which we published previously was not sufficient to develop PHAII, the decreased protein expression of KLHL3 observed in CUL3WT/Δ403-459 mice could be involved in the mechanism of PHAII caused by the CUL3 mutation in vivo. As KLHL2 and Keap1 were not decreased in CUL3 WT/Δ403-459mice, it might be a specific phenomenon in KLHL3.

Funding

  • Government Support - Non-U.S.