title: Comparison of the Ultrastructures of Primed and Naïve Mouse Embryonic Stem Cells.
abstract: Culture conditions have been established to maintain the pluripotency of mouse naïve and primed embryonic stem cells (ESCs) using human amnion epithelial cells (hAECs) as the feeder layer. In this study, the ultrastructures of mouse primed ESCs grown on hAECs were analyzed by transmission electron microscopy. Consistent with mouse naïve ESCs, the undifferentiated mouse primed ESC line ESD-EpiSC [ESC-derived epiblast stem cells (EpiSCs)] revealed typical characteristics, including large nuclei, reticulated nucleoli, scanty cytoplasm, and low cytoplasm-to-nuclear ratios. Cells had prominent Golgi apparatus and well-developed endoplasmic reticulum. Adjacent cells were tightly in contact with dense junction desmosomes. However, in EpiSC colonies, cell contact was no longer close like naïve ESCs, and differentiated cells existed. The differentiated cells had small nucleoli with large cytoplasm, which represented primitive mesenchyme. Phagosomes or apoptotic cells were also common in the cytoplasm of differentiated cells, which suggests a differentiation potential. When exposed to leukemia inhibitory factor (LIF), ESD-EpiSCs could convert to naïve-like cells. We further analyzed the ultrastructure of converted EpiSCs (cESCs). As compared to ESD-EpiSCs, cESCs showed similar ultrastructural characteristics as naïve ESCs. These findings suggest that ultrastructure could be used to evaluate the pluripotency of ESCs.
authors.affiliation: The International Peace Maternity and Child Health Hospital, School of Medicine, Shanghai Jiaotong University , Shanghai, China, 200030 .
authors.forename: Dongmei
authors.initials: D
authors.lastname: Lai
authors.affiliation: The International Peace Maternity and Child Health Hospital, School of Medicine, Shanghai Jiaotong University , Shanghai, China, 200030 .
authors.forename: Shixia
authors.initials: S
authors.lastname: Bu
mesh_terms: D000650:Amnion / Q000166:cytology; D000818:Animals; D002454:Cell Differentiation; D002478:Cells, Cultured; D061252:Feeder Cells; D005855:Germ Layers / Q000166:cytology / Q000648:ultrastructure; D006801:Humans; D051379:Mice; D000066450:Mouse Embryonic Stem Cells / Q000166:cytology* / Q000648:ultrastructure*; D039904:Pluripotent Stem Cells / Q000166:cytology / Q000648:ultrastructure