Conversion of Nonproliferating Astrocytes into Neurogenic Neural Stem Cells: Control by FGF2 and Interferon-γ.
Conversion of astrocytes to neurons, via de-differentiation to neural stem cells (NSC), may be a new approach to treat neurodegenerative diseases and brain injuries. The signaling factors affecting such a cell conversion are poorly understood, and they are hard to identify in complex disease models or conventional cell cultures. To address this question, we developed a serum-free, strictly controlled culture system of pure and homogeneous "astrocytes generated from murine embryonic stem cells (ESC)." These stem cell derived astrocytes (mAGES), as well as standard primary astrocytes resumed proliferation upon addition of FGF. The signaling of FGF receptor tyrosine kinase converted GFAP-positive mAGES to nestin-positive NSC. ERK phosphorylation was necessary, but not sufficient, for cell cycle re-entry, as EGF triggered no de-differentiation. The NSC obtained by de-differentiation of mAGES were similar to those obtained directly by differentiation of ESC, as evidenced by standard phenotyping, and also by transcriptome mapping, metabolic profiling, and by differentiation to neurons or astrocytes. The de-differentiation was negatively affected by inflammatory mediators, and in particular, interferon-γ strongly impaired the formation of NSC from mAGES by a pathway involving phosphorylation of STAT1, but not the generation of nitric oxide. Thus, two antagonistic signaling pathways were identified here that affect fate conversion of astrocytes independent of genetic manipulation. The complex interplay of the respective signaling molecules that promote/inhibit astrocyte de-differentiation may explain why astrocytes do not readily form neural stem cells in most diseases. Increased knowledge of such factors may provide therapeutic opportunities to favor such conversions. Stem Cells 2016;34:2861-2874.
Department of Biology, The Doerenkamp-Zbinden Chair of in-vitro Toxicology and Biomedicine/Alternatives to Animal Experimentation, University of Konstanz, Konstanz, Germany.
Susanne
S
Kleiderman
Department of Biology, The Doerenkamp-Zbinden Chair of in-vitro Toxicology and Biomedicine/Alternatives to Animal Experimentation, University of Konstanz, Konstanz, Germany.
Simon
S
Gutbier
Department of Biology, The Doerenkamp-Zbinden Chair of in-vitro Toxicology and Biomedicine/Alternatives to Animal Experimentation, University of Konstanz, Konstanz, Germany.|Department of Neuroscience, Institute of Health Sciences, Dokuz Eylul University, Inciralti, Izmir, Turkey.
Kemal
K
Ugur Tufekci
Institute/Department of Physiological Chemistry, Research Group Adult Neurogenesis and Cellular Reprogramming, Institute of Physiological Chemistry, University Medical Center of the Johannes Gutenberg University, Mainz, Germany.|Department of Biochemistry and Molecular Biology, Biochemistry and Molecular Biology Department, Faculty of Veterinary Medicine, Complutense University, Avenue Puerta de Hierro, Institute of Neurochemistry (IUIN), Spain and Health Research Institute of the Hospital Clinico San Carlos (IdISSC), Madrid, Spain.
Felipe
F
Ortega
IBET, Instituto de Biologia Experimental e Tecnológica, Oeiras, Portugal.|Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Av. da República, Oeiras, Portugal.
João V
JV
Sá
IBET, Instituto de Biologia Experimental e Tecnológica, Oeiras, Portugal.|Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Av. da República, Oeiras, Portugal.
Ana P
AP
Teixeira
IBET, Instituto de Biologia Experimental e Tecnológica, Oeiras, Portugal.|Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Av. da República, Oeiras, Portugal.
Catarina
C
Brito
Luxembourg Centre for Systems Biomedicine, University of Luxembourg, Belvaux, Luxembourg.
Enrico
E
Glaab
Institute/Department of Physiological Chemistry, Research Group Adult Neurogenesis and Cellular Reprogramming, Institute of Physiological Chemistry, University Medical Center of the Johannes Gutenberg University, Mainz, Germany.
Benedikt
B
Berninger
IBET, Instituto de Biologia Experimental e Tecnológica, Oeiras, Portugal.|Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Av. da República, Oeiras, Portugal.
Paula M
PM
Alves
Department of Biology, The Doerenkamp-Zbinden Chair of in-vitro Toxicology and Biomedicine/Alternatives to Animal Experimentation, University of Konstanz, Konstanz, Germany.
Marcel
M
Leist
D000818:Animals; D001253:Astrocytes / Q000166:cytology* / Q000187:drug effects; D002453:Cell Cycle / Q000187:drug effects; D054337:Cell Dedifferentiation / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D004815:Epidermal Growth Factor / Q000494:pharmacology; D016222:Fibroblast Growth Factor 2 / Q000494:pharmacology*; D005786:Gene Expression Regulation / Q000187:drug effects; D007371:Interferon-gamma / Q000494:pharmacology*; D051379:Mice; D000066450:Mouse Embryonic Stem Cells / Q000166:cytology / Q000187:drug effects; D039902:Multipotent Stem Cells / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D058953:Neural Stem Cells / Q000166:cytology* / Q000187:drug effects; D055495:Neurogenesis / Q000187:drug effects; D015398:Signal Transduction / Q000187:drug effects
D016222:Fibroblast Growth Factor 2; D004815:Epidermal Growth Factor; D007371:Interferon-gamma
Astrocytes; De-differentiation; FGF2; Interferon; Neural stem cells; Neurogenesis