Spironolactone Rescues Dot1a-Af9-Mediated Repression of Endothelin-1 and Improves Kidney Injury in Streptozotocin-Induced Diabetic Rats

Abstract

The molecular mechanism linking aldosterone and endothelin-1 in the development of diabetic nephropathy has not been completely elucidated. Here, we provide evidence showing that streptozotocin-induced diabetic rats have significantly increased aldosterone and endothelin-1 in the kidney tissue and markedly decreased expression of Dot1a and Af9. Blocking aldosterone with spironolactone significantly reduced proteinuria, glomerulosclerosis, tubulointerstitial injury and endothelin-1 expression, and significantly increased Dot1a and Af9 expression. Increasing Dot1a and Af9 expression by spironolactone or by stable transfection led to impaired endothelin-1 expression in NRK-52 cells. In contrast, downregulation of Dot1a and Af9 by aldosterone in NRK-52E cells caused upregulation of endothelin-1. Genetic inactivation of Dot1l, which encodes Dot1a, in Aqp2-expressing principal cells of mouse kidney impaired association of Dot1a and H3 dimethyl K79 with the specific subregions of endothelin-1 promoter, and upregulates endothelin-1 mRNA and protein expression. Our data suggest that Dot1a and Af9 repress endothelin-1 in vitro and in vivo. Excessive aldosterone induces kidney injury, in part possibly by downregulating Dot1a and Af9, and thus relieving Dot1a-Af9-mediated repression to increase endothelin-1 transcription. Spironolactone ameliorates kidney injury in Streptozotocin-induced diabetic rats, possibly by restoring Dot1a-Af9-mediated repression to reduce endothelin-1 expression. Therefore, Dot1a and Af9 as aldosterone-downregulated targets are negative regulators of endothelin-1 transcription in vitro and in vivo, and may be considered as new potential therapeutic targets of kidney injury in diabetes.

Dot1l deficiency leads to increased intercalated cells and upregulation of V-ATPase B1 in mice

“…Our current study adds Atp6v1b1 to the growing list of Dot1a target genes including αENaC, endothelin-1, and Aqp5 [18, 24, 31]. Our previous studies have shown that Af9 recruits Dot1a to the specific subregions of αENaC promoter [32].…”

“…ChIP coupled with deep sequencing (ChIP-seq) in human CD4+ T cells established a slight correlation between H3m1K79 and gene activation, a more close association of H3m3K79 with gene repression, and no correlation of H3m2K79 with transcriptional status [43]. Unlike genome-wide analyses, our gene-specific ChIP studies were focused on the upstream regions extending into the first exons of the genes examined including αENaC [16, 24, 44], Edn1 [31], Aqp5 [18], and Atp6v1b1 (Figure 6). We consistently found that Dot1l and H3m2K79 were specifically located in the regions examined.…”

A genome-wide association study identifies PLCL2 and AP3D1-DOT1L-SF3A2 as new susceptibility loci for myocardial infarction in Japanese

“…DOT1L was shown to positively regulate GATA2 expression, 33 which is known to regulate the transcription of endothelial cell-specific genes. 34 In particular, DOT1L was shown to be negatively correlated with endothelin-1, 35 which has an important role in vasospasm and vasoconstriction. Additionally, the binding capacity of AP3D1 was found to be regulated by angiotensinogen, 36 suggesting that AP3D1 might be related to atherosclerosis in concert with a potent atherosclerotic substrate, angiotensin II.…”

Epigenetics and the Control of the Collecting Duct Epithelial Sodium Channel

“…Mammalian DOT1L plays key roles in embryogenesis, hematopoiesis, heart function, kidney function, and in MLL-related leukemogenesis 23 . In addition to its roles in the control of ENaC in the collecting duct, intriguing new data has implicated Dot1 in the control of collecting duct water channel 25 and endothelin expression 26 , and mesangial cell connective tissue growth factor expression 27 .…”