Our laboratory is interested in various aspects of the Na,K-ATPase, including structure-function relationships and understanding the regulated expression of the isoforms of the alpha and beta subunits. We are especially interested in the physiological role this enzyme plays and have recently developed animals lacking the alpha1 and alpha2 isoforms. Of particular significance from these studies is the finding that each isoform plays a different role in heart and skeletal muscle contraction. We wish to follow up on these studies as well as pursue others that are related to the in vivo role of this enzyme.
The specific aims of our grant are to use a replacement gene targeting approach to determine whether the cardiac glycoside binding site of the Na,K-ATPase plays a biological role. Such studies will help define whether natural ligands exist for this enzyme and the role that they might play. In our second aim, we will use these animals to define the role of individual alpha isoforms in mediating the positive and negative effects of cardiac glycoside therapy.
A third aim relates to understanding the physiological role of each of the alpha isoforms using chimeric analysis and tissue-specific knockouts. Animals lacking the alpha2 isoform fail to survive past birth and these animals provide an opportunity for understanding the specific biological niche that this isoform plays. In order to more fully define the tissue responsile for the lethal phenotype, we plan to carry out chimeric studies with embryonic stem cells which lack both copies of the alpha2 isoform and to carry out tissue-specific knockouts. These approaches will help define which organ system(s) is responsible for the failure of the animals to develop past birth. These studies will also likely provide animals with tissues lacking the alpha2 isoform and make it possible to define the role of this isoform in that tissue.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
5R01HL066062-04
Application #
6684159
Study Section
Pharmacology A Study Section (PHRA)
Program Officer
Wang, Lan-Hsiang
Project Start
2001-01-01
Project End
2005-06-30
Budget Start
2003-12-01
Budget End
2005-06-30
Support Year
4
Fiscal Year
2004
Total Cost
$382,500
Indirect Cost
Name
University of Cincinnati
Department
Genetics
Type
Schools of Medicine
DUNS #
041064767
City
Cincinnati
State
OH
Country
United States
Zip Code
45221
Lorenz, John N; Oshiro, Naomi; Loreaux, Elizabeth L et al. (2012) DOCA-salt hypertension does not require the ouabain-sensitive binding site of the ?2 Na,K-ATPase. Am J Hypertens 25:421-9
Wansapura, Arshani N; Lasko, Valerie M; Lingrel, Jerry B et al. (2011) Mice expressing ouabain-sensitive ?1-Na,K-ATPase have increased susceptibility to pressure overload-induced cardiac hypertrophy. Am J Physiol Heart Circ Physiol 300:H347-55
Lingrel, Jerry B (2010) The physiological significance of the cardiotonic steroid/ouabain-binding site of the Na,K-ATPase. Annu Rev Physiol 72:395-412
Oshiro, Naomi; Dostanic-Larson, Iva; Neumann, Jon C et al. (2010) The ouabain-binding site of the ?2 isoform of Na,K-ATPase plays a role in blood pressure regulation during pregnancy. Am J Hypertens 23:1279-85
Hou, Xiaohong; Theriault, Steven F; Dostanic-Larson, Iva et al. (2009) Enhanced pressor response to increased CSF sodium concentration and to central ANG I in heterozygous alpha2 Na+ -K+ -ATPase knockout mice. Am J Physiol Regul Integr Comp Physiol 296:R1427-38
Blaustein, Mordecai P; Zhang, Jin; Chen, Ling et al. (2009) The pump, the exchanger, and endogenous ouabain: signaling mechanisms that link salt retention to hypertension. Hypertension 53:291-8
Radzyukevich, T L; Lingrel, J B; Heiny, J A (2009) The cardiac glycoside binding site on the Na,K-ATPase alpha2 isoform plays a role in the dynamic regulation of active transport in skeletal muscle. Proc Natl Acad Sci U S A 106:2565-70
Wansapura, Arshani N; Lasko, Valerie; Xie, Zijian et al. (2009) Marinobufagenin enhances cardiac contractility in mice with ouabain-sensitive alpha1 Na+-K+-ATPase. Am J Physiol Heart Circ Physiol 296:H1833-9
Lorenz, John N; Loreaux, Elizabeth L; Dostanic-Larson, Iva et al. (2008) ACTH-induced hypertension is dependent on the ouabain-binding site of the alpha2-Na+-K+-ATPase subunit. Am J Physiol Heart Circ Physiol 295:H273-80
Loreaux, Elizabeth L; Kaul, Baksho; Lorenz, John N et al. (2008) Ouabain-Sensitive alpha1 Na,K-ATPase enhances natriuretic response to saline load. J Am Soc Nephrol 19:1947-54

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