Morphological analysis of human induced pluripotent stem cells during induced differentiation and reverse programming.
The fine analysis of cell components during the generation of pluripotent cells and their comparison to bone fide human embryonic stem cells (hESCs) are valuable tools to understand their biological behavior. In this report, human mesenchymal cells (hMSCs) generated from the human ES cell line H9, were reprogrammed back to induced pluripotent state using Oct-4, Sox2, Nanog, and Lin28 transgenes. Human induced pluripotent stem cells (hIPSCs) were analyzed using electron microscopy and compared with regard to the original hESCs and the hMSCs from which they were derived. This analysis shows that hIPSCs and the original hESCs are morphologically undistinguishable but differ from the hMSCs with respect to the presence of several morphological features of undifferentiated cells at both the cytoplasmic (ribosomes, lipid droplets, glycogen, scarce reticulum) and nuclear levels (features of nuclear plasticity, presence of euchromatin, reticulated nucleoli). We show that hIPSC colonies generated this way presented epithelial aspects with specialized junctions highlighting morphological criteria of the mesenchymal-epithelial transition in cells engaged in a successful reprogramming process. Electron microscopic analysis revealed also specific morphological aspects of partially reprogrammed cells. These results highlight the valuable use of electron microscopy for a better knowledge of the morphological aspects of IPSC and cellular reprogramming.
Inserm U935, ES-TEAM Paris Sud, Ingestem , Villejuif, France . ; Université Paris Sud , Faculté de Médecine, Le Kremlin Bicêtre, France .
Anne-Marie
AM
Courtot
Inserm U935, ES-TEAM Paris Sud, Ingestem , Villejuif, France .
Aurélie
A
Magniez
Inserm U935, ES-TEAM Paris Sud, Ingestem , Villejuif, France . ; Service d'Hématologie Biologique APHP, Hôpital Paul Brousse , GHU Paris Sud Villejuif, France .
Noufissa
N
Oudrhiri
Inserm U935, ES-TEAM Paris Sud, Ingestem , Villejuif, France .
Olivier
O
Féraud
Service de Neurologie, Hôpital Bicêtre APHP , Le Kremlin Bicêtre, France .
Josette
J
Bacci
Inserm U935, ES-TEAM Paris Sud, Ingestem , Villejuif, France .
Emilie
E
Gobbo
Service de Virologie, Hôpital Bicêtre APHP , Le Kremlin Bicêtre, France .
Stéphanie
S
Proust
Inserm U935, ES-TEAM Paris Sud, Ingestem , Villejuif, France . ; Université Paris Sud , Faculté de Médecine, Le Kremlin Bicêtre, France . ; Service d'Hématologie Biologique APHP, Hôpital Bicêtre , GHU Paris Sud, Le Kremlin Bicêtre, France .
Ali G
AG
Turhan
Inserm U935, ES-TEAM Paris Sud, Ingestem , Villejuif, France . ; Université Paris Sud , Faculté de Médecine, Le Kremlin Bicêtre, France . ; Service d'Hématologie Biologique APHP, Hôpital Paul Brousse , GHU Paris Sud Villejuif, France .
Annelise
A
Bennaceur-Griscelli
MEF; Matrigel; ducts; euchromatin; glycogen; hESC; hIPSC; hMSC; lipid droplets; macroautophagy; mesenchymal-to-epithelial transition; nucleoli; specialized junction