Ca2+ signaling in human induced pluripotent stem cell-derived cardiomyocytes (iPS-CM) from normal and catecholaminergic polymorphic ventricular tachycardia (CPVT)-afflicted subjects

Cell Calcium. 2013 Aug;54(2):57-70. doi: 10.1016/j.ceca.2013.04.004. Epub 2013 May 17.


Derivation of cardiomyocytes from induced pluripotent stem cells (iPS-CMs) allowed us to probe the Ca(2+)-signaling parameters of human iPS-CMs from healthy- and catecholaminergic polymorphic ventricular tachycardia (CPVT1)-afflicted individuals carrying a novel point mutation p.F2483I in ryanodine receptors (RyR2). iPS-CMs were dissociated on day 30-40 of differentiation and patch-clamped within 3-6 days. Calcium currents (ICa) averaged ∼8pA/pF in control and mutant iPS-CMs. ICa-induced Ca(2+)-transients in control and mutant cells had bell-shaped voltage-dependence similar to that of ICa, consistent with Ca(2+)-induced Ca(2+)-release (CICR) mechanism. The ratio of ICa-activated to caffeine-triggered Ca(2+)-transients was ∼0.3 in both cell types. Caffeine-induced Ca(2+)-transients generated significantly smaller Na(+)-Ca(2+) exchanger current (INCX) in mutant cells, reflecting their smaller Ca(2+)-stores. The gain of CICR was voltage-dependent as in adult cardiomyocytes. Adrenergic agonists enhanced ICa, but differentially altered the CICR gain, diastolic Ca(2+), and Ca(2+)-sparks in mutant cells. The mutant cells, when Ca(2+)-overloaded, showed longer and wandering Ca(2+)-sparks that activated adjoining release sites, had larger CICR gain at -30mV yet smaller Ca(2+)-stores. We conclude that control and mutant iPS-CMs express the adult cardiomyocyte Ca(2+)-signaling phenotype. RyR2 F2483I mutant myocytes have aberrant unitary Ca(2+)-signaling, smaller Ca(2+)-stores, higher CICR gains, and sensitized adrenergic regulation, consistent with functionally altered Ca(2+)-release profile of CPVT syndrome.

Keywords: CICR gain; CPVT; Calcium signaling; Mutation in RyR2 gene; Pluripotent stem cells.

Publication types

  • Comparative Study
  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adrenergic Agonists / pharmacology
  • Adult
  • Caffeine / pharmacology
  • Calcium / metabolism*
  • Calcium Signaling / physiology*
  • Catecholamines / metabolism*
  • Cell Differentiation
  • Cell Line
  • Cells, Cultured
  • Humans
  • In Vitro Techniques
  • Myocytes, Cardiac / drug effects
  • Myocytes, Cardiac / metabolism*
  • Myocytes, Cardiac / pathology
  • Patch-Clamp Techniques
  • Pluripotent Stem Cells / metabolism*
  • Pluripotent Stem Cells / pathology
  • Point Mutation / genetics
  • Ryanodine Receptor Calcium Release Channel / genetics
  • Ryanodine Receptor Calcium Release Channel / metabolism
  • Tachycardia, Ventricular / metabolism*
  • Tachycardia, Ventricular / pathology


  • Adrenergic Agonists
  • Catecholamines
  • Ryanodine Receptor Calcium Release Channel
  • Caffeine
  • Calcium