Phospholamban as a crucial determinant of the inotropic response of human pluripotent stem cell-derived ventricular cardiomyocytes and engineered 3-dimensional tissue constructs

Gaopeng Chen, Sen Li, Ioannis Karakikes, Lihuan Ren, Maggie Zi-Ying Chow, Anant Chopra, Wendy Keung, Bin YAN, Camie W.Y. Chan, Kevin D. Costa, Chi Wing Kong, Roger J. Hajjar, Christopher S. Chen, Ronald A. Li*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

24 Citations (Scopus)

Abstract

Background - Human (h) embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs) serve as a potential unlimited ex vivo source of cardiomyocytes (CMs). However, a well-accepted roadblock has been their immature phenotype. hESC/iPSC-derived ventricular (v) CMs and their engineered cardiac microtissues (hvCMTs) similarly displayed positive chronotropic but null inotropic responses to β-adrenergic stimulation. Given that phospholamban (PLB) is robustly present in adult but poorly expressed in hESC/iPSC-vCMs and its defined biological role in β-adrenergic signaling, we investigated the functional consequences of PLB expression in hESC/iPSC-vCMs and hvCMTs. Methods and Results - First, we confirmed that PLB protein was differentially expressed in hESC (HES2, H9)- and iPSC-derived and adult vCMs. We then transduced hES2-vCMs with the recombinant adenoviruses (Ad) Ad-PLB or Ad-S16E-PLB to overexpress wild-type PLB or the pseudophosphorylated point-mutated variant, respectively. As anticipated from the inhibitory effect of unphosphorylated PLB on sarco/endoplasmic reticulum Ca 2+ -ATPase, Ad-PLB transduction significantly attenuated electrically evoked Ca 2+ transient amplitude and prolonged the 50% decay time. Importantly, Ad-PLB-transduced hES2-vCMs uniquely responded to isoproterenol. Ad-S16E-PLB-transduced hES2-vCMs displayed an intermediate phenotype. The same trends were observed with H9- and iPSC-vCMs. Directionally, similar results were also seen with Ad-PLB-transduced and Ad-S16E-transduced hvCMTs. However, Ad-PLB altered neither the global transcriptome nor I Ca,L, implicating a PLB-specific effect. Conclusions - Engineered upregulation of PLB expression in hESC/iPSC-vCMs restores a positive inotropic response to β-adrenergic stimulation. These results not only provide a better mechanistic understanding of the immaturity of hESC/iPSC-vCMs but will also lead to improved disease models and transplantable prototypes with adult-like physiological responses.

Original languageEnglish
Pages (from-to)193-202
Number of pages10
JournalCirculation: Arrhythmia and Electrophysiology
Volume8
Issue number1
DOIs
Publication statusPublished - 28 Feb 2015

Scopus Subject Areas

  • Cardiology and Cardiovascular Medicine
  • Physiology (medical)

User-Defined Keywords

  • adrenergic effects
  • phospholamban
  • pluripotent stem cells
  • tissues

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