Abstract: SA-PO750
Hydrogen Sulfide Attenuates CKD Progression by Inducing TET-Dependent DNA Demethylation on Klotho Promoter
Session Information
- CKD: Mechanisms - III
November 09, 2019 | Location: Exhibit Hall, Walter E. Washington Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: CKD (Non-Dialysis)
- 2103 CKD (Non-Dialysis): Mechanisms
Authors
- Gu, Yulu, Zhongshan Hospital, Fudan University, Shanghai, China
- Ding, Xiaoqiang, Zhongshan Hospital, Fudan University, Shanghai, China
- Zhang, Xiaoyan, Zhongshan Hospital, Fudan University, Shanghai, China
Background
Hydrogen sulfide has been reported to attenuate renal fibrosis. A recent study shows hydrogen sulfide can demethylate its target genes by upregulating TET1 expression in regulatory T cells. Our previous study revealed Klotho hypermethylation in CKD patients, suggesting possible involvement of Klotho promoter hypermethylation in the development of CKD This study aims to investigate whether H2S can directly change TET hydroxylase expression or activity as well as subsequent DNA demethylation in renal fibrosis.
Methods
C57BL/6 mice underwent unilateral ureter obstruction(UUO) with or without NaHS treatment. Multiple techniques were used to analyze the extent of tubulointerstitial fibrosis and renal hypoxia, the methylation and hydroxymethylation level of renal Klotho promotors, and the expression and activity of TETs. In vitro, HK2 cells received hypoxia treatment. The level of cellular ROS and ferrous ion was examined to further explore the role of hypoxia on TETs enzyme activity and Klotho methylation.
Results
Evidenced by Masson staining and the expression of α-SMA and Fibronectin, NaHS treatment reduced renal fibrosis in UUO mice. Also, it upregulated Klotho expression, decreased Klotho methylation level and increased Klotho hydroxymethylation level, along with increased TETs activity, rather than TETs expression. Moreover, NaHS reduced hypoxic areas of UUO-injured kidney. In vitro, hypoxia increased Klotho methylation level and decreased TET activity. In hypoxic HK2 cells, the level of total ROS and nuclear ROS were raised. Both H2O2 and hypoxia reduced the concentration of cellular Fe2+. While ascorbate rescued hypoxia-induced decrease of TETs activity.
Conclusion
Hypoxia causes Klotho hypermethylation by decreasing TETs enzyme activity through ROS-induced Fe2+ reduction. And hydrogen sulfide attenuates renal fibrosis by improving hypoxia and enhancing TETs enzyme, which induces Klotho demethylation and restores Klotho.
NaHS administration demethylates Klotho in UUO mice.
Funding
- Government Support - Non-U.S.