Spironolactone rescues Dot1a-Af9-mediated repression of endothelin-1 and improves kidney injury in streptozotocin-induced diabetic rats.
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.
Department of Nephropathy, Xiangya Hospital, Central South University, Changsha City, Hunan Province, People's Republic of China. zhouqling@yahoo.com.cn
Qiaoling
Q
Zhou
Kanghan
K
Liu
Hongyu
H
Wu
Lihe
L
Chen
Veeraragoo
V
Pouranan
Mingxia
M
Yuan
Zhou
Z
Xiao
Weisheng
W
Peng
Ao
A
Xiang
Rong
R
Tang
Wenzheng
W
Zhang
D058186:Acute Kidney Injury / Q000139:chemically induced / Q000188:drug therapy / Q000378:metabolism; D000450:Aldosterone / Q000378:metabolism; D000818:Animals; D003921:Diabetes Mellitus, Experimental / Q000139:chemically induced / Q000188:drug therapy / Q000378:metabolism*; D003928:Diabetic Nephropathies / Q000188:drug therapy / Q000235:genetics; D015536:Down-Regulation / Q000187:drug effects; D019332:Endothelin-1 / Q000235:genetics / Q000378:metabolism*; D011495:Histone-Lysine N-Methyltransferase; D006801:Humans; D008780:Methyltransferases / Q000235:genetics* / Q000378:metabolism; D051379:Mice; D009687:Nuclear Proteins / Q000235:genetics* / Q000378:metabolism; D011401:Promoter Regions, Genetic; D051381:Rats; D013148:Spironolactone / Q000008:administration & dosage*; D013311:Streptozocin / Q000633:toxicity; D015854:Up-Regulation / Q000187:drug effects
D019332:Endothelin-1; C489902:Mllt3 protein, mouse; D009687:Nuclear Proteins; D013148:Spironolactone; D000450:Aldosterone; D013311:Streptozocin; C481527:Dot1l protein, mouse; D008780:Methyltransferases; D011495:Histone-Lysine N-Methyltransferase