title: Exogenous and fibroblast growth factor 2/epidermal growth factor-regulated endogenous cytokines regulate neural precursor cell growth and differentiation.
abstract: 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.
authors.affiliation: INSERM U583, INM-Hôpital Saint Eloi, 80 rue Augustin Fliche, 34295 Montpellier, France.
authors.forename: Loïc
authors.initials: L
authors.lastname: Deleyrolle
authors.forename: Sophie
authors.initials: S
authors.lastname: Marchal-Victorion
authors.forename: Cécile
authors.initials: C
authors.lastname: Dromard
authors.forename: Vanessa
authors.initials: V
authors.lastname: Fritz
authors.forename: Monique
authors.initials: M
authors.lastname: Saunier
authors.forename: Jean-Charles
authors.initials: JC
authors.lastname: Sabourin
authors.forename: Christophe
authors.initials: C
authors.lastname: Tran Van Ba
authors.forename: Alain
authors.initials: A
authors.lastname: Privat
authors.forename: Jean-Philippe
authors.initials: JP
authors.lastname: Hugnot
mesh_terms: 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*
chemical_list: D004815:Epidermal Growth Factor; C496354:Fgfr2 protein, mouse; D051497:Receptor, Fibroblast Growth Factor, Type 2