Effects of FGF-2 and EGF removal on the differentiationof mouse neural precursor cells

Telma T Schwindt,Alessander O Guimarães,Massant Cristina G,Barnabé Gabriela F,Luiz E Mello,Fabiana L Motta,João B Pesquero,Maria Elisa Calcagnotto

doi:10.1590/s0001-37652009000300009

Telma T Schwindt, Alessander O Guimarães + Show 6 more

Open Access

https://doi.org/10.1590/s0001-37652009000300009

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Abstract

Cell therapy for neurological disorders has advanced, and neural precursor cells (NPC) may become the ideal candidates for neural transplantation in a wide range of diseases. However, additional work has to be done to determine either the ideal culture environment for NPC expansion in vitro, without altering their plasticity, or the FGF-2 and EGF mechanisms of cell signaling in neurospheres growth, survival and differentiation. In this work we evaluated mouse neurospheres cultured with and without FGF-2 and EGF containing medium and showed that those growth factors are responsible for NPC proliferation. It is also demonstrated that endogenous production of growth factors shifts from FGF-2 to IGF-1/PDGFb upon EGF and FGF-2 withdrawal. Mouse NPC cultured in suspension showed different patterns of neuronal localization (core versus shell) for both EGF and FGF-2 withdrawal and control groups. Taken together, these results show that EGF and FGF-2 removal play an important role in NPC differentiation and may contribute to a better understanding of mechanisms of NPC differentiation. Our findings suggest that depriving NPC of growth factors prior to grafting might enhance their chance to effectively integrate into the host.

Highlights

Evidence of neurogenesis in the adult brain of birds (Goldman and Nottebohm 1983), rodents and primates (Kuhn et al 1996, Gould et al 1999, Kuhn and Svendsen 1999), and the demonstration of stem cells in specific brain regions, such as the subventricular zone and the hippocampus (Eriksson et al 1998, Van Praag et al 2002), brought new perspectives for cell therapy and neural regeneration (Svendsen and Smith 1999)
To assess if there was a significant difference in growth and in the expression of growth factors and neural specific proteins between the CTR and E/F-less groups, three independent cultures of mNPC derived from E14 embryos were subjected to growth factors deprivation for 11 days, followed by analyses of proliferation, cell death and differentiation
Given that growth factors removal leads to a decrease in cell proliferation, we expected to find cells undergoing differentiation, even in suspension

Summary

Introduction

Evidence of neurogenesis in the adult brain of birds (Goldman and Nottebohm 1983), rodents and primates (Kuhn et al 1996, Gould et al 1999, Kuhn and Svendsen 1999), and the demonstration of stem cells in specific brain regions, such as the subventricular zone and the hippocampus (Eriksson et al 1998, Van Praag et al 2002), brought new perspectives for cell therapy and neural regeneration (Svendsen and Smith 1999). An experimental model to study neural stem cells is the heterogeneous free floating aggregates of cells, termed neurospheres (Reynolds and Weiss 1996, McKay 1997, Gage 2000). The progenitor cells, in turn, give rise only to other progenitor cells. In this way, only a small fraction of the neurosphere corresponds to real stem cells (Reynolds et al 1992). We use the terminology neural precursor cells (NPC) to describe both cell types within the neurosphere (Svendsen et al 1999, Svendsen and Caldwell 2000)

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