Neural differentiation of embryonic stem cells is induced by signalling from non-neural niche cells.
OBJECTIVE
Embryonic stem cell (ESC) transplantation offers new therapeutic strategies for neurodegenerative diseases and injury. However, the mechanisms underlying integration and differentiation of engrafted ESCs are poorly understood. This study elucidates the influence of exogenous signals on ESC differentiation using in vitro modelling of non-stem/stem cell interactions.


METHODS
Murine ESCs were co-cultured with endothelial cells and astrocytes or conditioned medium obtained from endothelial or astrocyte cultures. After 7 days of co-culture isolated RNA was analysed using RT-PCR for the expression of pluripotency marker oct-4, neural progenitor marker nestin, and neurofilament (NFL), an early marker of neuronal lineage commitment. The presence of the glial cell surface marker A2B5 was determined in ESCs by flow cytometry.


RESULTS
Neuronal differentiation was inhibited in ESCs when grown in close vicinity to cerebral endothelial or glial cells. Under these conditions, ESC differentiation was predominantly directed towards a glial fate. However, treatment of ESCs with endothelial cell- or astrocyte-conditioned medium promoted neuronal as well as glial differentiation.


CONCLUSIONS
Our results indicate that ESC fate is determined by endothelial and glial cells that comprise the environmental niche of these stem cells in vivo. The direction of differentiation processes appears to be dependent on humoral factors secreted by adjacent cell lines.
Bentz
Kristine
K
Institute of Developmental Genetics, GSF - National Research Centre for Environment and Health, Munich/Neuherberg, Germany.
Molcanyi
Marek
M
Hess
Simone
S
Schneider
Annette
A
Hescheler
Juergen
J
Neugebauer
Edmund
E
Schaefer
Ute
U
D000818:Animals; D001253:Astrocytes / Q000502:physiology*; D015415:Biomarkers / Q000032:analysis; D001921:Brain / Q000166:cytology; D002454:Cell Differentiation; D019070:Cell Lineage / Q000235:genetics; D018920:Coculture Techniques; D017077:Culture Media, Conditioned; D053595:Embryonic Stem Cells / Q000166:cytology* / Q000502:physiology; D042783:Endothelial Cells / Q000502:physiology; D007381:Intermediate Filament Proteins / Q000235:genetics; D051379:Mice; D009419:Nerve Tissue Proteins / Q000235:genetics; D064231:Nestin; D016900:Neurofilament Proteins / Q000235:genetics; D009474:Neurons / Q000166:cytology*; D050814:Octamer Transcription Factor-3 / Q000235:genetics; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction
D015415:Biomarkers; D017077:Culture Media, Conditioned; D007381:Intermediate Filament Proteins; D009419:Nerve Tissue Proteins; C577485:Nes protein, mouse; C577486:Nes protein, rat; D064231:Nestin; D016900:Neurofilament Proteins; D050814:Octamer Transcription Factor-3; D012333:RNA, Messenger