DNA methylation protects against cisplatin-induced kidney injury by regulating specific genes, including interferon regulatory factor 8

Abstract

DNA methylation is an epigenetic mechanism that regulates gene transcription without changing primary nucleotide sequences. In mammals, DNA methylation involves the covalent addition of a methyl group to the 5-carbon position of cytosine by DNA methyltransferases (DNMTs). The change of DNA methylation and its pathological role in acute kidney injury (AKI) remain largely unknown. Here, we analyzed genome-wide DNA methylation during cisplatin-induced AKI by reduced representation bisulfite sequencing. This technique identified 215 differentially methylated regions between the kidneys of control and cisplatin-treated animals. While most of the differentially methylated regions were in the intergenic, intronic and coding DNA sequences, some were located in the promoter or promoter regulatory regions of 15 protein-coding genes. To determine the pathological role of DNA methylation, we initially examined the effects of DNA methylation inhibitor 5-Aza-2′-deoxycytidine and showed it increased cisplatin-induced apoptosis in a rat kidney proximal tubular cell line. We further established a kidney proximal tubule-specific DNMT1 (PT-DNMT1) knockout mouse model, which showed more severe AKI during cisplatin treatment than wild-type mice. Finally, interferon regulatory factor 8 (Irf8), a pro-apoptotic factor, was identified as a hypomethylated gene in cisplatin-induced AKI and this hypomethylation was associated with a marked induction of Irf8. In the rat kidney proximal tubular cells, knockdown of Irf8 suppressed cisplatin-induced apoptosis, supporting a pro-death role of Irf8 in renal tubular cells. Thus, DNA methylation plays a protective role in cisplatin-induced AKI by regulating specific genes, such as Irf8.

PINK1/Parkin-mediated mitophagy is activated in cisplatin nephrotoxicity to protect against kidney injury

“…Renal failure or loss of renal function was revealed by serum creatinine and BUN using commercial kits as previously described 43 , 44 . After coagulation, blood samples were centrifuged at room temperature to collect the serum.…”

“…Apoptosis were determined in kidney tissues by TUNEL assay by using the In Situ Cell Death Detection Kit from Roche Applied Science (Indianapolis, IN) as described in our recent work 43 , 44 . Briefly, kidney tissues were embedded in paraffin and deparaffinized with a standard protocol.…”

AKI on CKD: heightened injury, suppressed repair, and the underlying mechanisms

“…The development of diabetic nephropathy is also associated with DNA methylation changes in specific genes 200 . Interestingly, significant changes in DNA methylation occurs cisplatin-induced AKI and blockade of DNA methylation sensitizes kidney injury, suggesting a protective role of DNA methylation in AKI 201 . In terms of specific genes, the hypermethylation of klotho gene promoter in CKD conditions has been reported by several laboratories 202–207 .…”

The Contribution of Histone Crotonylation to Tissue Health and Disease: Focus on Kidney Health

“…Global kidney DNA methylation was reduced in experimental AKI induced by ischemia-reperfusion injury (IRI) or cisplatin, and this was associated to the expression of inflammatory genes (Guo et al, 2017;Zhao et al, 2017). In this regard, DNA methylation contributes to silencing the expression of the nephroprotective genes Klotho (which has anti-inflammatory and anti-fibrotic properties) and RASAL1 (which has anti-fibrotic properties) in AKI.…”