Spironolactone rescues Dot1a-Af9-mediated repression of endothelin-1 and improves kidney injury in streptozotocin-induced diabetic rats

PLoS One. 2012;7(10):e47360. doi: 10.1371/journal.pone.0047360. Epub 2012 Oct 15.

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.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acute Kidney Injury / chemically induced
  • Acute Kidney Injury / drug therapy
  • Acute Kidney Injury / metabolism
  • Aldosterone / metabolism
  • Animals
  • Diabetes Mellitus, Experimental / chemically induced
  • Diabetes Mellitus, Experimental / drug therapy
  • Diabetes Mellitus, Experimental / metabolism*
  • Diabetic Nephropathies / drug therapy
  • Diabetic Nephropathies / genetics
  • Down-Regulation / drug effects
  • Endothelin-1 / genetics
  • Endothelin-1 / metabolism*
  • Histone-Lysine N-Methyltransferase
  • Humans
  • Methyltransferases / genetics*
  • Methyltransferases / metabolism
  • Mice
  • Nuclear Proteins / genetics*
  • Nuclear Proteins / metabolism
  • Promoter Regions, Genetic
  • Rats
  • Spironolactone / administration & dosage*
  • Streptozocin / toxicity
  • Up-Regulation / drug effects

Substances

  • Endothelin-1
  • Mllt3 protein, mouse
  • Nuclear Proteins
  • Spironolactone
  • Aldosterone
  • Streptozocin
  • Dot1l protein, mouse
  • Methyltransferases
  • Histone-Lysine N-Methyltransferase