title: Direct control of Na(+)-K(+)-2Cl(-)-cotransport protein (NKCC1) expression with aldosterone.
abstract: Sodium/potassium/chloride cotransporter (NKCC1) proteins play important roles in Na(+) and K(+) concentrations in key physiological systems, including cardiac, vascular, renal, nervous, and sensory systems. NKCC1 levels and functionality are altered in certain disease states, and tend to decline with age. A sensitive, effective way of regulating NKCC1 protein expression has significant biotherapeutic possibilities. The purpose of the present investigation was to determine if the naturally occurring hormone aldosterone (ALD) could regulate NKCC1 protein expression. Application of ALD to a human cell line (HT-29) revealed that ALD can regulate NKCC1 protein expression, quite sensitively and rapidly, independent of mRNA expression changes. Utilization of a specific inhibitor of mineralocorticoid receptors, eplerenone, implicated these receptors as part of the ALD mechanism of action. Further experiments with cycloheximide (protein synthesis inhibitor) and MG132 (proteasome inhibitor) revealed that ALD can upregulate NKCC1 by increasing protein stability, i.e., reducing ubiquitination of NKCC1. Having a procedure for controlling NKCC1 protein expression opens the doors for therapeutic interventions for diseases involving the mis-regulation or depletion of NKCC1 proteins, for example during aging.
authors.affiliation: Department of Communication Sciences and Disorders, Global Center for Hearing and Speech Research, University of South Florida, Tampa, Florida;
authors.forename: Bo
authors.initials: B
authors.lastname: Ding
authors.forename: Robert D
authors.initials: RD
authors.lastname: Frisina
authors.forename: Xiaoxia
authors.initials: X
authors.lastname: Zhu
authors.forename: Yoshihisa
authors.initials: Y
authors.lastname: Sakai
authors.forename: Bernd
authors.initials: B
authors.lastname: Sokolowski
authors.forename: Joseph P
authors.initials: JP
authors.lastname: Walton
mesh_terms: D000450:Aldosterone / Q000494:pharmacology*; D005786:Gene Expression Regulation; D019073:HT29 Cells; D006801:Humans; D055550:Protein Stability / Q000187:drug effects; D012333:RNA, Messenger / Q000096:biosynthesis; D064506:Solute Carrier Family 12, Member 2 / Q000096:biosynthesis*; D015854:Up-Regulation / Q000187:drug effects / Q000502:physiology
chemical_list: D012333:RNA, Messenger; C578877:SLC12A2 protein, human; D064506:Solute Carrier Family 12, Member 2; D000450:Aldosterone
keywords: NKCC1; Na+-K+-2Cl--cotransport protein; aging; pathway regulation; physiological systems; steroid hormone; therapeutics