Local control of excitation-contraction coupling in human embryonic stem cell-derived cardiomyocytes

Wei Zhong Zhu, Luis Fernando Santana, Michael A. Laflamme

Research output: Contribution to journalArticle

60 Citations (Scopus)

Abstract

We investigated the mechanisms of excitation-contraction (EC) coupling in human embryonic stem cell-derived cardiomyocytes (hESC-CMs) and fetal ventricular myocytes (hFVMs) using patch-clamp electrophysiology and confocal microscopy. We tested the hypothesis that Ca2+ influx via voltage-gated L-type Ca2+ channels activates Ca2+ release from the sarcoplasmic reticulum (SR) via a local control mechanism in hESC-CMs and hFVMs. Field-stimulated, whole-cell [Ca2+]i transients in hESC-CMs required Ca2+ entry through L-type Ca2+ channels, as evidenced by the elimination of such transients by either removal of extracellular Ca2+ or treatment with diltiazem, an L-type channel inhibitor. Ca2+ release from the SR also contributes to the [Ca2+]i transient in these cells, as evidenced by studies with drugs interfering with either SR Ca2+ release (i.e. ryanodine and caffeine) or reuptake (i.e. thapsigargin and cyclopiazonic acid). As in adult ventricular myocytes, membrane depolarization evoked large L-type Ca2+ currents (ICa) and corresponding whole-cell [Ca2+]i transients in hESC-CMs and hFVMs, and the amplitude of both ICa and the [Ca2+]i transients were finely graded by the magnitude of the depolarization. hESC-CMs exhibit a decreasing EC coupling gain with depolarization to more positive test potentials, "tail" [Ca2+]i transients upon repolarization from extremely positive test potentials, and co-localized ryanodine and sarcolemmal L-type Ca2+ channels, all findings that are consistent with the local control hypothesis. Finally, we recorded Ca2+ sparks in hESC-CMs and hFVMs. Collectively, these data support a model in which tight, local control of SR Ca2+ release by the ICa during EC coupling develops early in human cardiomyocytes.

Original languageEnglish (US)
Article numbere5407
JournalPLoS One
Volume4
Issue number4
DOIs
StatePublished - Apr 30 2009
Externally publishedYes

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Excitation Contraction Coupling
embryonic stem cells
Stem cells
Cardiac Myocytes
calcium
Depolarization
Muscle Cells
Sarcoplasmic Reticulum
Ryanodine
sarcoplasmic reticulum
myocytes
Electrophysiology
Thapsigargin
Diltiazem
Confocal microscopy
Clamping devices
Caffeine
Electric sparks
Human Embryonic Stem Cells
cardiomyocytes

ASJC Scopus subject areas

  • Agricultural and Biological Sciences(all)
  • Biochemistry, Genetics and Molecular Biology(all)
  • Medicine(all)

Cite this

Local control of excitation-contraction coupling in human embryonic stem cell-derived cardiomyocytes. / Zhu, Wei Zhong; Santana, Luis Fernando; Laflamme, Michael A.

In: PLoS One, Vol. 4, No. 4, e5407, 30.04.2009.

Research output: Contribution to journalArticle

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