Exogenous and fibroblast growth factor 2/epidermal growth factor-regulated endogenous cytokines regulate neural precursor cell growth and differentiation.
Neurospheres (NSs) are clonal cellular aggregates composed of neural stem cells and progenitors. A comprehensive description of their proliferation and differentiation regulation is an essential prerequisite for their use in biotherapies. Cytokines are essential molecules regulating cell precursor fate. Using a gene-array strategy, we conducted a descriptive and functional analysis of endogenous cytokines and receptors expressed by spinal cord-derived NSs during their growth or their differentiation into neuronal and glial cells. NSs were found to express approximately 100 receptor subunits and cytokine/secreted developmental factors. Several angiogenic factors and receptors that could mediate neural precursor cell-endothelial cell relationships were detected. Among them, receptor B for endothelins was highly expressed, and endothelins were found to increase NS growth. In contrast, NSs express receptors for ciliary neurotrophic factor (CNTF), bone morphogenetic protein (BMP), interferon (IFN)-gamma, or tumor necrosis factor (TNF)-alpha, which, when added in the growth phase, led to a dramatic growth reduction followed by a reduction or a loss of oligodendrocyte formation on differentiation. In addition, NSs synthesize fibroblast growth factor 2/epidermal growth factor (FGF2/EGF)-regulated endogenous cytokines that participate in their growth and differentiation. Notably, BMP-7 and CNTF were expressed during expansion, but upon differentiation there was a remarkable switch from BMP-7 to BMP-4 and -6 and a sharp increase of CNTF. Reintroduction of growth factors reverses the BMP expression profile, indicating growth factor-BMP cross-regulations. The role of endogenous CNTF was investigated by deriving NSs from CNTF knockout mice. These NSs have an increased growth rate associated with reduction of apoptosis and generate astrocytes with a reduced glial fibulary acidic protein (GFAP) content. These results demonstrate the combined role of endogenous and exogenous cytokines in neural precursor cell growth and differentiation.
Deleyrolle
Loïc
L
INSERM U583, INM-Hôpital Saint Eloi, 80 rue Augustin Fliche, 34295 Montpellier, France.
Marchal-Victorion
Sophie
S
Dromard
Cécile
C
Fritz
Vanessa
V
Saunier
Monique
M
Sabourin
Jean-Charles
JC
Tran Van Ba
Christophe
C
Privat
Alain
A
Hugnot
Jean-Philippe
JP
D000818:Animals; D002454:Cell Differentiation / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D002478:Cells, Cultured; D004815:Epidermal Growth Factor / Q000378:metabolism* / Q000494:pharmacology; D005727:Ganglia, Spinal / Q000166:cytology / Q000502:physiology*; D051379:Mice; D008822:Mice, Transgenic; D009474:Neurons / Q000166:cytology / Q000502:physiology; D009836:Oligodendroglia / Q000166:cytology / Q000502:physiology; D051497:Receptor, Fibroblast Growth Factor, Type 2 / Q000378:metabolism* / Q000494:pharmacology; D013234:Stem Cells / Q000166:cytology / Q000502:physiology*
D004815:Epidermal Growth Factor; C496354:Fgfr2 protein, mouse; D051497:Receptor, Fibroblast Growth Factor, Type 2