Nitric oxide regulates cardiac intracellular Na+ and Ca2+ by modulating Na/K ATPase via PKC epsilon 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*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

27 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

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

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