Physiological and ultrastructural features of human induced pluripotent and embryonic stem cell-derived skeletal myocytes in vitro.
Progress has recently been made toward the production of human skeletal muscle cells from induced pluripotent stem (iPS) cells. However, the functional and ultrastructural characterization, which is crucial for disease modeling and drug discovery, remains to be documented. We show, for the first time to our knowledge, that the electrophysiological properties of human iPS-derived skeletal myocytes are strictly similar to those of their embryonic stem (ES) cell counterparts, and both are typical of aneural mammalian skeletal muscle. In both cell types, intracellular calcium signaling that links membrane depolarization to contraction occurs in the absence of extracellular Ca(2+), a unique feature of skeletal muscle. Detailed analysis of the Ca(2+) signal revealed diverse kinetics of the rising phase, and hence various rates in the release of Ca(2+) from the sarcoplasmic reticulum. This was mirrored by ultrastructural evidence of Ca(2+) release units, which varied in location, shape, and size. Thus, the excitation-contraction coupling machinery of both iPS- and ES-derived skeletal myocytes was functional and specific, but did not reach full maturity in culture. This is in contrast with the myofibrillar network, which displayed the same organization as in adult skeletal muscle. Overall, the present study validates the human iPS-based skeletal myocyte model in comparison with the embryonic system, and provides the functional and ultrastructural basis for its application to human skeletal muscle diseases.
Département de Physiologie, Université Pierre et Marie Curie, Site Pitié-Salpêtrière, 75013 Paris, France;
Gunnar
G
Skoglund
Département de Physiologie, Université Pierre et Marie Curie, Site Pitié-Salpêtrière, 75013 Paris, France;
Jeanne
J
Lainé
Lillehei Heart Institute, Department of Medicine, University of Minnesota, Minneapolis, MN 55455; and.
Radbod
R
Darabi
Département de Physiologie, Université Pierre et Marie Curie, Site Pitié-Salpêtrière, 75013 Paris, France;
Emmanuel
E
Fournier
Lillehei Heart Institute, Department of Medicine, University of Minnesota, Minneapolis, MN 55455; and.
Rita
R
Perlingeiro
Département de Physiologie, Université Pierre et Marie Curie, Site Pitié-Salpêtrière, 75013 Paris, France;Université Paris Est Créteil, 94010 Créteil, France nacira.tabti@upmc.fr.
Nacira
N
Tabti
D000185:Actinin / Q000378:metabolism; D020013:Calcium Signaling / Q000502:physiology*; D002454:Cell Differentiation / Q000502:physiology; D002460:Cell Line; D002467:Cell Nucleus / Q000648:ultrastructure; D048430:Cell Shape / Q000502:physiology; D053595:Embryonic Stem Cells / Q000166:cytology*; D056966:Excitation Contraction Coupling / Q000502:physiology; D005434:Flow Cytometry; D006801:Humans; D066298:In Vitro Techniques; D008564:Membrane Potentials / Q000502:physiology; D018485:Muscle Fibers, Skeletal / Q000502:physiology* / Q000648:ultrastructure*; D009210:Myofibrils / Q000648:ultrastructure; D039904:Pluripotent Stem Cells / Q000166:cytology*; D012519:Sarcoplasmic Reticulum / Q000648:ultrastructure
D000185:Actinin
EC coupling; electrophysiology; human ES-myocyte; human iPS-myocyte; ultrastructure