Melanocyte-like cells in the heart and pulmonary veins contribute to atrial arrhythmia triggers.
Atrial fibrillation is the most common clinical cardiac arrhythmia. It is often initiated by ectopic beats arising from the pulmonary veins and atrium, but the source and mechanism of these beats remains unclear. The melanin synthesis enzyme dopachrome tautomerase (DCT) is involved in intracellular calcium and reactive species regulation in melanocytes. Given that dysregulation of intracellular calcium and reactive species has been described in patients with atrial fibrillation, we investigated the role of DCT in this process. Here, we characterize a unique DCT-expressing cell population within murine and human hearts that populated the pulmonary veins, atria, and atrioventricular canal. Expression profiling demonstrated that this population expressed adrenergic and muscarinic receptors and displayed transcriptional profiles distinct from dermal melanocytes. Adult mice lacking DCT displayed normal cardiac development but an increased susceptibility to atrial arrhythmias. Cultured primary cardiac melanocyte-like cells were excitable, and those lacking DCT displayed prolonged repolarization with early afterdepolarizations. Furthermore, mice with mutations in the tyrosine kinase receptor Kit lacked cardiac melanocyte-like cells and did not develop atrial arrhythmias in the absence of DCT. These data suggest that dysfunction of melanocyte-like cells in the atrium and pulmonary veins may contribute to atrial arrhythmias.
Penn Cardiovascular Institute and University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA.
Mark D
MD
Levin
Min Min
MM
Lu
Nataliya B
NB
Petrenko
Brian J
BJ
Hawkins
Tara H
TH
Gupta
Deborah
D
Lang
Peter T
PT
Buckley
Jeanine
J
Jochems
Fang
F
Liu
Christopher F
CF
Spurney
Li J
LJ
Yuan
Jason T
JT
Jacobson
Christopher B
CB
Brown
Li
L
Huang
Friedrich
F
Beermann
Kenneth B
KB
Margulies
Muniswamy
M
Madesh
James H
JH
Eberwine
Jonathan A
JA
Epstein
Vickas V
VV
Patel
D000818:Animals; D001145:Arrhythmias, Cardiac / Q000201:enzymology* / Q000235:genetics; D055724:Electrophysiological Phenomena; D016166:Free Radical Scavengers / Q000378:metabolism; D020869:Gene Expression Profiling; D015971:Gene Expression Regulation, Enzymologic; D006801:Humans; D019746:Intramolecular Oxidoreductases / Q000235:genetics / Q000378:metabolism*; D008544:Melanocytes / Q000201:enzymology* / Q000648:ultrastructure; D051379:Mice; D018345:Mice, Knockout; D009206:Myocardium / Q000166:cytology* / Q000473:pathology; D011667:Pulmonary Veins / Q000166:cytology*; D020794:Receptor Protein-Tyrosine Kinases / Q000235:genetics; D011941:Receptors, Adrenergic / Q000378:metabolism; D011976:Receptors, Muscarinic / Q000378:metabolism
D016166:Free Radical Scavengers; D011941:Receptors, Adrenergic; D011976:Receptors, Muscarinic; D020794:Receptor Protein-Tyrosine Kinases; D019746:Intramolecular Oxidoreductases; C042501:dopachrome isomerase