title: Short-term withdrawal of mitogens prior to plating increases neuronal differentiation of human neural precursor cells.
abstract: BACKGROUND
  Human neural precursor cells (hNPC) are candidates for neural transplantation in a wide range of neurological disorders. Recently, much work has been done to determine how the environment for NPC culture in vitro may alter their plasticity. Epidermal growth factor (EGF) and fibroblast growth factor-2 (FGF-2) are used to expand NPC; however, it is not clear if continuous exposure to mitogens may abrogate their subsequent differentiation. Here we evaluated if short-term removal of FGF-2 and EGF prior to plating may improve hNPC differentiation into neurons.
  
  
  RESULTS
  We demonstrate that culture of neurospheres in suspension for 2 weeks without EGF-FGF-2 significantly increases neuronal differentiation and neurite extension when compared to cells cultured using standard protocols. In this condition, neurons were preferentially located in the core of the neurospheres instead of the shell. Moreover, after plating, neurons presented radial rather than randomly oriented and longer processes than controls, comprised mostly by neurons with short processes. These changes were followed by alterations in the expression of genes related to cell survival.
  
  
  CONCLUSIONS
  These results show that EGF and FGF-2 removal affects NPC fate and plasticity. Taking into account that a three dimensional structure is essential for NPC differentiation, here we evaluated, for the first time, the effects of growth factors removal in whole neurospheres rather than in plated cell culture.
authors.affiliation: Department of Physiology, Universidade Federal de São Paulo, São Paulo, Brazil.
authors.forename: Telma Tiemi
authors.initials: TT
authors.lastname: Schwindt
authors.forename: Fabiana Louise
authors.initials: FL
authors.lastname: Motta
authors.forename: Gabriela Filoso
authors.initials: GF
authors.lastname: Barnabé
authors.forename: Cristina Gonçalves
authors.initials: CG
authors.lastname: Massant
authors.forename: Alessander de Oliveira
authors.initials: Ade O
authors.lastname: Guimarães
authors.forename: Maria Elisa
authors.initials: ME
authors.lastname: Calcagnotto
authors.forename: Fabio Silva
authors.initials: FS
authors.lastname: Conceição
authors.forename: João Bosco
authors.initials: JB
authors.lastname: Pesquero
authors.forename: Stevens
authors.initials: S
authors.lastname: Rehen
authors.forename: Luiz E
authors.initials: LE
authors.lastname: Mello
mesh_terms: D002454:Cell Differentiation / Q000187:drug effects*; D020869:Gene Expression Profiling; D005904:Glial Fibrillary Acidic Protein / Q000378:metabolism; D006801:Humans; D007381:Intermediate Filament Proteins / Q000378:metabolism; D008934:Mitogens / Q000494:pharmacology*; D009419:Nerve Tissue Proteins / Q000378:metabolism; D064231:Nestin; D009474:Neurons / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D013234:Stem Cells / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D014404:Tubulin / Q000378:metabolism
chemical_list: D005904:Glial Fibrillary Acidic Protein; D007381:Intermediate Filament Proteins; D008934:Mitogens; C577484:NES protein, human; D009419:Nerve Tissue Proteins; D064231:Nestin; D014404:Tubulin