Low-dose 5-aza-2′-deoxycytidine protects against early renal injury by increasing klotho expression

Abstract

Aim: To explore the effect of the DNA methyltransferase inhibitor 5-aza-2′-deoxycytidine (Aza) on early renal injury. Materials & methods: Cell damage and inflammation are features of early renal injury. The apoptosis and inflammation in hypoxia/reoxygenation (H/R)-induced human proximal tubular epithelial cells (HK-2) and ischemia–reperfusion kidney were studied, and expression of the protein klotho was investigated. Results: Aza induced HK-2 apoptosis in a dose-dependent manner, but low-dose Aza attenuated the apoptosis and inflammation in H/R-induced HK-2 cells and ischemia–reperfusion kidney. Low-dose Aza ameliorated renal function in mice with renal ischemia–reperfusion injury. Meanwhile, low-dose Aza upregulated klotho expression in H/R-induced HK-2 cells and ischemia–reperfusion kidney. Klotho knockdown abrogated the effects of low-dose Aza on apoptosis and inflammation. Conclusion: Low-dose Aza protects against renal early injury by increasing klotho expression.

Plain language summary

DNA methylation affects kidney disease and might be a clinically useful therapeutic target for kidney disease. It has been reported that blocking DNA methylation may reduce renal fibrosis. Early renal injury is a priming event of late renal function failure, and inhibition of early renal injury may be beneficial to prevent late loss of function. In this study, the DNA methyltransferase inhibitor 5-aza-2′-deoxycytidine was studied for its effects on cell apoptosis and inflammation in early renal injury. Low-dose 5-aza-2′-deoxycytidine had antiapoptotic and anti-inflammatory effects on HK-2 cells induced by hypoxia/reoxygenation and renal tissue with ischemia–reperfusion injury (IRI), and improved renal function following renal IRI. Possible mechanisms involved reduced methylation of klotho promoter DNA and upregulation of klotho expression. Therefore, it is attractive to speculate that preventing DNA methylation may be an effective strategy or method to attenuate renal early injury or renal IRI in human patients, as it is in rodents.

Keywords::

• 5-aza-2′-deoxycytidine
• apoptosis
• DNA methyltransferase
• inflammation
• klotho
• renal

Supplementary data

To view the supplementary data that accompany this paper please visit the journal website at: www.tandfonline.com/doi/suppl/10.2217/epi-2022-0430

Author contributions

Y Zhao conceived the designs and performed most of the experiments, analyzed the results and wrote the manuscript. X Zeng and X Xu helped with designing the experiments and revising the article. W Wang, L Xu, Y Wu and H Li performed some experiments. All authors contributed to the article and approved the submitted version.

Financial & competing interests disclosure

This work was supported by the National Natural Science Foundation of China (81873176), the Key R & D projects in Shaanxi Province (2020SF-331). The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.

No writing assistance was utilized in the production of this manuscript.

Ethical conduct of research

The authors state that they have obtained appropriate institutional review board approval or have followed the principles outlined in the Declaration of Helsinki for all human or animal experimental investigations. The study was approved by the Institutional Animal Care and Use Committee at the Shaanxi Provincial Hospital of Chinese Medicine.

Additional information

Funding

This work was supported by the National Natural Science Foundation of China (81873176), the Key R & D projects in Shaanxi Province (2020SF-331). The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed. No writing assistance was utilized in the production of this manuscript.