Klotho is a novel therapeutic target in peritoneal fibrosis via Wnt signaling inhibition.

Abstract

BACKGROUND:

Long-term exposure to bioincompatible peritoneal dialysate causes the loss of mesothelial cells and accumulation of matrix proteins, leading to an increase in the thickness of the submesothelial layer, thereby limiting the long-term effectiveness of peritoneal dialysis (PD). However, the detailed molecular mechanisms underlying the process of peritoneal fibrosis have not been clearly elucidated. Wnt/β-catenin signaling pathway activation has been suggested to play a pivotal role in the development of organ fibrosis. Moreover, Klotho protein can regulate Wnt/β-catenin signaling. We examined the role of Klotho protein in reducing peritoneal fibrosis by inhibiting Wnt/β-catenin signaling.

METHODS:

The β-catenin-activated transgenic (BAT) driving expression of nuclear β-galactosidase reporter transgenic (BAT-LacZ) mice, the alpha-Klotho gene under control of human elongation factor 1 alpha promoter [Klotho transgenic (KLTG) and C57BL/6 background] and C57BL/6 mice [wild-type (WT)] were used. The mice received daily intraperitoneal (i.p.) injections of 4.25% glucose with lactate (PD solution) or saline as a control for 4 weeks. Other mice received daily i.p. injections of the same volume of saline (normal control).

RESULTS:

After exposure to PD, Wnt signal activation was observed on the peritoneal mesothelial cells in WT-PD mice. The peritoneal fibrosis was also accelerated in WT-PD mice. The protein expression of β-catenin and Wnt-inducible genes were also remarkably increased in WT-PD mice. On the other hand, KLTG-PD mice attenuated activation of Wnt/β-catenin signaling after exposure to PD and ameliorated the progression of peritoneal fibrosis.

CONCLUSIONS:

Overexpression of Klotho protein protects the peritoneal membrane through attenuation of the Wnt/β-catenin signaling pathway. The availability of recombinant Klotho protein would provide a novel potential therapeutic target in peritoneal fibrosis.

• Authors: Hiroyuki Kadoya, Minoru Satoh, Yuko Nishi, Megumi Kondo, Yoshihisa Wada, Yuji Sogawa, Kengo Kidokoro, Hajime Nagasu, Tamaki Sasaki, Naoki Kashihara
• Journal: Nephrology, dialysis, transplantation : official publication of the European Dialysis and Transplant Association - European Renal Association (Nephrol Dial Transplant) Vol. 35 Issue 5 Pg. 773-781 (05 01 2020) ISSN: 1460-2385 [Electronic] England
• PMID: 32221606 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: © The Author(s) 2020. Published by Oxford University Press on behalf of ERA-EDTA. All rights reserved.

Chemical References

• CTNNB1 protein, mouse
• Wnt Proteins
• beta Catenin
• Glucuronidase
• Klotho Proteins

Topics

• Animals
• Glucuronidase (physiology)
• Humans
• Klotho Proteins
• Mice
• Mice, Inbred C57BL
• Mice, Transgenic
• Peritoneal Dialysis (adverse effects)
• Peritoneal Fibrosis (etiology, pathology, therapy)
• Wnt Proteins (antagonists & inhibitors, metabolism)
• beta Catenin (antagonists & inhibitors, metabolism)