title: Increasing the physical size and nucleation status of human pluripotent stem cell-derived ventricular cardiomyocytes by cell fusion.
abstract: Human pluripotent stem cell-derived cardiomyocytes (hPSC-CMs) provide an unlimited source of donor cells for potential cardiac regenerative therapies. However, hPSC-CMs are immature. For instance, hPSC-CMs are only 1/10 of the physical size of their adult counterparts; the majority are mono- rather than bi- or multi-nucleated, which is an evolutionary adaptive feature in metabolically active cells such as adult CMs. Here, we attempted to increase the physical size and nucleation status of hPSC-derived ventricular (V) cardiomyocytes (hPSC-VCMs) using chemically-induced cell fusion, and examined the subsequent functional effects. Polyethylene glycol (PEG) was employed to fuse a 1:1 mixture of lentiviral vectors LV-MLC2v-GFP- or -tdTomato-labeled hPSC-VCMs, such that hPSC-VCMs fused syncytia (FS) were identified as doubly GFP+/tdTomato+multi-nucleated cells. These microscopically-identified FS were doubled in size as gauged by their capacitance when compared to the control mononucleated hPSC-VCMs using patch-clamp analysis. Reduced automaticity or action potential (AP) firing rate and moderately prolonged AP duration were observed in FS from day 6 post-fusion induction. However, Ca2+handling, mitochondrial biogenesis and the extent of apoptosis were not significantly altered. We conclude that larger, multi-nucleated hPSC-VCMs FS can be created by chemically-induced cell fusion but global maturation requires additional triggering cues.
authors.affiliation: Stem Cell & Regenerative Medicine Consortium, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong; Department of Paediatrics and Adolescent Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong; School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong. Electronic address: marcokong@hku.hk.
authors.forename: Chi-Wing
authors.initials: CW
authors.lastname: Kong
authors.affiliation: Department of Mechanical and Biomedical Engineering, City University of Hong Kong, Hong Kong.
authors.forename: Shuxun
authors.initials: S
authors.lastname: Chen
authors.affiliation: Stem Cell & Regenerative Medicine Consortium, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong; School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong; Dr. Li Dak-Sum Centre, The University of Hong Kong, Hong Kong.
authors.forename: Lin
authors.initials: L
authors.lastname: Geng
authors.affiliation: Stem Cell & Regenerative Medicine Consortium, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong; School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong.
authors.forename: Angie Man-Yee
authors.initials: AM
authors.lastname: Shum
authors.affiliation: Department of Mechanical and Biomedical Engineering, City University of Hong Kong, Hong Kong.
authors.forename: Dong
authors.initials: D
authors.lastname: Sun
authors.affiliation: Department of Paediatrics and Adolescent Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong; Dr. Li Dak-Sum Centre, The University of Hong Kong, Hong Kong; Ming Wai Lau Centre for Reparative Medicine, Karolinska Institutet, Sweden.
authors.forename: Ronald A
authors.initials: RA
authors.lastname: Li
mesh_terms: D000200:Action Potentials / Q000187:drug effects; D017209:Apoptosis / Q000187:drug effects; D002459:Cell Fusion; D002460:Cell Line; D048429:Cell Size; D005434:Flow Cytometry; D005822:Genetic Vectors / Q000235:genetics / Q000378:metabolism; D015726:Giant Cells / Q000166:cytology / Q000502:physiology; D006352:Heart Ventricles / Q000166:cytology; D000066449:Human Embryonic Stem Cells / Q000166:cytology; D006801:Humans; D016086:Lentivirus / Q000235:genetics; D008164:Luminescent Proteins / Q000235:genetics / Q000378:metabolism; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects; D018613:Microscopy, Confocal; D032383:Myocytes, Cardiac / Q000166:cytology* / Q000502:physiology; D018408:Patch-Clamp Techniques; D039904:Pluripotent Stem Cells / Q000166:cytology* / Q000502:physiology; D011092:Polyethylene Glycols / Q000494:pharmacology
chemical_list: D008164:Luminescent Proteins; D011092:Polyethylene Glycols
keywords: Cell fusion; Electrophysiological maturation; Human pluripotent stem cell-derived ventricular cardiomyocytes (hPSC-VCMs); Hypertrophy; Multi-nucleation