Role of Sodium Channel Deglycosylation in the Genesis of Cardiac Arrhythmias in Heart Failure

Carmen A. Ufret-Vincenty, Deborah J. Baro, W. Jonathan Lederer, Howard A. Rockman, Luis E. Quiñones, Luis Fernando Santana

Research output: Contribution to journalArticle

98 Scopus citations

Abstract

We investigated the cellular and molecular mechanisms underlying arrhythmias in heart failure. A genetically engineered mouse lacking the expression of the muscle LIM protein (MLP-/-) was used in this study as a model of heart failure. We used electrocardiography and patch clamp techniques to examine the electrophysiological properties of MLP-/- hearts. We found that MLP-/- myocytes had smaller Na+ currents with altered voltage dependencies of activation and inactivation and slower rates of inactivation than control myocytes. These changes in Na + currents contributed to longer action potentials and to a higher probability of early afterdepolarizations in MLP-/- than in control myocytes. Western blot analysis suggested that the smaller Na+ current in MLP-/- myocytes resulted from a reduction in Na + channel protein. Interestingly, the blots also revealed that the α-subunit of the Na+ channel from the MLP-/- heart had a lower average molecular weight than in the control heart. Treating control myocytes with the sialidase neuraminidase mimicked the changes in voltage dependence and rate of inactivation of Na+ currents observed in MLP-/- myocytes. Neuraminidase had no effect on MLP-/- cells thus suggesting that Na+ channels in these cells were sialic acid-deficient. We conclude that deficient glycosylation of Na+ channel contributes to Na+ current-dependent arrhythmogenesis in heart failure.

Original languageEnglish (US)
Pages (from-to)28197-28203
Number of pages7
JournalJournal of Biological Chemistry
Volume276
Issue number30
DOIs
StatePublished - Jul 27 2001
Externally publishedYes

ASJC Scopus subject areas

  • Biochemistry

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