Physiol. Genomics 36: 52-58, 2008.
First published September 30, 2008; doi:10.1152/physiolgenomics.90283.2008
1094-8341/08 $8.00
Received 1 July 2008;
accepted in final form 26 September 2008.
Physiological Genomics 36:52-58 (2008)
1094-8341/08 $8.00 © 2008 American Physiological Society
Renal medullary 11β-hydroxysteroid dehydrogenase type 1 in Dahl salt-sensitive hypertension
Yong Liu1,
Ravinder J. Singh2,
Kristie Usa1,
Brian C. Netzel2 and
Mingyu Liang1
1 Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin
2 Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota
The Dahl salt-sensitive rat is a widely used model of human salt-sensitive forms of hypertension. The kidney plays an important role in the pathogenesis of Dahl salt-sensitive hypertension, but the molecular mechanisms involved remain a subject of intensive investigation. Gene expression profiling studies suggested that 11β-hydroxysteroid dehydrogenase type 1 might be dysregulated in the renal medulla of Dahl salt-sensitive rats. Additional analysis confirmed that renal medullary expression of 11β-hydroxysteroid dehydrogenase type 1 was downregulated by a high-salt diet in SS-13BN rats, a consomic rat strain with reduced blood pressure salt sensitivity, but not in Dahl salt-sensitive rats. 11β-Hydroxysteroid dehydrogenase type 1 is known to convert inactive 11-dehydrocorticosterone to active corticosterone. The urinary corticosterone/11-dehydrocorticosterone ratio as well as urinary excretion of corticosterone was higher in Dahl salt-sensitive rats than in SS-13BN rats. Knockdown of renal medullary 11β-hydroxysteroid dehydrogenase type 1 with small-interfering RNA attenuated the early phase of salt-induced hypertension in Dahl salt-sensitive rats and reduced urinary excretion of corticosterone. Knockdown of 11β-hydroxysteroid dehydrogenase type 1 did not affect blood pressure in SS-13BN rats. Long-term attenuation of salt-induced hypertension was achieved with small hairpin RNA targeting renal medullary 11β-hydroxysteroid dehydrogenase type 1. In summary, we have demonstrated that suppression of 11β-hydroxysteroid dehydrogenase type 1 expression in the renal medulla attenuates salt-induced hypertension in Dahl salt-sensitive rats.
blood pressure; glucocorticoids; gene expression; gene therapy; RNA interference
Copyright © 2008 by the American Physiological Society.