Nitric oxide regulates cardiac intracellular Na(+) and Ca(2+) by modulating Na/K ATPase via PKCε and phospholemman-dependent mechanism

Davor Pavlovic, Andrew R. Hall, Erika J. Kennington, Karen Aughton, Andrii Boguslavskyi, William Fuller, Sanda Despa, Donald M. Bers, Michael J. Shattock (Lead / Corresponding author)

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    22 Citations (Scopus)

    Abstract

    In the heart, Na/K-ATPase regulates intracellular Na+ and Ca2+ (via NCX), thereby preventing Na+ and Ca2+ overload and arrhythmias. Here, we test the hypothesis that nitric oxide (NO) regulates cardiac intracellular Na+ and Ca2+ and investigate mechanisms and physiological consequences involved. Effects of both exogenous NO (via NO-donors) and endogenously synthesized NO (via field-stimulation of ventricular myocytes) were assessed in this study. Field stimulation of rat ventricular myocytes significantly increased endogenous NO (18 +/- 2 mu M), PKC epsilon activation (82 +/- 12%), phospholemman phosphorylation (at Ser-63 and Ser-68) and Na/K-ATPase activity (measured by DAF-FM dye, western-blotting and biochemical assay, respectively; p <0.05, n = 6) and all were abolished by Ca2+-chelation (EGTA 10 mM) or NOS inhibition L-NAME (1 mM). Exogenously added NO (spermine-NONO-ate) stimulated Na/K-ATPase (EC50 = 3.8 mu M; n = 6/grp), via decrease in K-m, in PLMWT but not PLMKO or PLM3SA myocytes (where phospholemman cannot be phosphorylated) as measured by whole-cell perforated-patch clamp. Field-stimulation with L-NAME or PKC-inhibitor (2 mu M Bis) resulted in elevated intracellular Na+ (22 +/- 1.5 and 24 +/- 2 respectively, vs. 14 +/- 0.6 mM in controls) in SBFI-AM-loaded rat myocytes. Arrhythmia incidence was significantly increased in rat hearts paced in the presence of L-NAME (and this was reversed by L-arginine), as well as in PLM3SA mouse hearts but not PLMWT and PLMKO. We provide physiological and biochemical evidence for a novel regulatory pathway whereby NO activates Na/K-ATPase via phospholemman phosphorylation and thereby limits Na+ and Ca2+ overload and arrhythmias. This article is part of a Special Issue entitled "Na+ Regulation in Cardiac Myocytes". (C) 2013 The Authors. Published by Elsevier Ltd. All rights reserved.

    Original languageEnglish
    Pages (from-to)164-171
    Number of pages8
    JournalJournal of Molecular and Cellular Cardiology
    Volume61
    DOIs
    Publication statusPublished - Aug 2013

    Keywords

    • Protein kinase C
    • Arrhythmia
    • Sodium pump
    • FXYD-1
    • K-ATPASE
    • Phospholemman
    • ACTIVATION
    • NA,K-ATPASE ACTIVITY
    • SYNTHASE
    • PROTEIN-KINASE-C
    • IN-VITRO
    • STIMULATION
    • VENTRICULAR MYOCYTES
    • PHOSPHOLAMBAN PHOSPHORYLATION
    • PUMP FUNCTION
    • Nitric oxide

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