2016 journal article

Same-Single-Cell Analysis of Pacemaker-Specific Markers in Human Induced Pluripotent Stem Cell-Derived Cardiomyocyte Subtypes Classified by Electrophysiology.

Stem Cells (Dayton, Ohio), 11.

By: S. Yechikov*, R. Copaciu*, J. Gluck* , W. Deng *, N. Chiamvimonvat *, J. Chan *, D. Lieu *

author keywords: Human induced pluripotent stem cells; Cardiomyocyte subtype; Electrophysiology; Pacemaker
MeSH headings : Action Potentials / physiology; Biomarkers / metabolism; Cell Differentiation; Cell Line; Cell Lineage / genetics; Electrophysiology; Gene Expression; Heart Atria / cytology; Heart Atria / metabolism; Heart Conduction System / cytology; Heart Conduction System / metabolism; Heart Ventricles / cytology; Heart Ventricles / metabolism; Humans; Hyperpolarization-Activated Cyclic Nucleotide-Gated Channels / genetics; Hyperpolarization-Activated Cyclic Nucleotide-Gated Channels / metabolism; Immunohistochemistry; Induced Pluripotent Stem Cells / cytology; Induced Pluripotent Stem Cells / metabolism; LIM-Homeodomain Proteins / genetics; LIM-Homeodomain Proteins / metabolism; Muscle Proteins / genetics; Muscle Proteins / metabolism; Myocytes, Cardiac / cytology; Myocytes, Cardiac / metabolism; Organ Specificity; Potassium Channels / genetics; Potassium Channels / metabolism; Single-Cell Analysis / methods; Transcription Factors / genetics; Transcription Factors / metabolism
TL;DR: expression of proposed pacemaker‐specific markers—hyperpolarization‐activated cyclic nucleotide‐modulated (HCN)4 channel and Islet (Isl)1)—at the protein level in all three hiPSC‐derived cardiomyocyte subtypes are revealed. (via Semantic Scholar)
Source: ORCID
Added: August 20, 2019

Abstract Insights into the expression of pacemaker-specific markers in human induced pluripotent stem cell (hiPSC)-derived cardiomyocyte subtypes can facilitate the enrichment and track differentiation and maturation of hiPSC-derived pacemaker-like cardiomyocytes. To date, no study has directly assessed gene expression in each pacemaker-, atria-, and ventricular-like cardiomyocyte subtype derived from hiPSCs since currently the subtypes of these immature cardiomyocytes can only be identified by action potential profiles. Traditional acquisition of action potentials using patch-clamp recordings renders the cells unviable for subsequent analysis. We circumvented these issues by acquiring the action potential profile of a single cell optically followed by assessment of protein expression through immunostaining in that same cell. Our same-single-cell analysis for the first time revealed expression of proposed pacemaker-specific markers—hyperpolarization-activated cyclic nucleotide-modulated (HCN)4 channel and Islet (Isl)1—at the protein level in all three hiPSC-derived cardiomyocyte subtypes. HCN4 expression was found to be higher in pacemaker-like hiPSC-derived cardiomyocytes than atrial- and ventricular-like subtypes but its downregulation over time in all subtypes diminished the differences. Isl1 expression in pacemaker-like hiPSC-derived cardiomyocytes was initially not statistically different than the contractile subtypes but did become statistically higher than ventricular-like cells with time. Our observations suggest that although HCN4 and Isl1 are differentially expressed in hiPSC-derived pacemaker-like relative to ventricular-like cardiomyocytes, these markers alone are insufficient in identifying hiPSC-derived pacemaker-like cardiomyocytes.