Valproic acid (VPA), a short-chain fatty acid, is used clinically as an anticonvulsant and mood stabilizer. Valproic acid also inhibits histone deacetylase activity, which is associated with histone hyperacetylation and changes in gene expression. In this study, we examined the effects of VPA on the expression of selected neurotrophic and differentiation factors in C17.2 neural stem cells. Reverse transcription-polymerase chain reaction analysis revealed a significant increase in conserved dopamine neurotrophic factor (CDNF) and glial cell line-derived neurotrophic factor mRNA expression, after treatment with clinically relevant concentrations of VPA (0.5 or 1.0 mM) for 24 hr. Increases in the protein expression of CDNF and mesencephalic astrocytederived neurotrophic factor were also observed, after similar treatment with VPA. In addition, significant increases in the mRNA levels of the early dopaminergic neuron marker, nuclear receptor-related protein 1(Nurr1), and the transcriptional regulator, early growth response protein 1 (Egr1), were observed after treatment with VPA for 24 hr. C17.2 neural stem cells exhibited high basal mRNA expression of brain-derived neurotrophic factor and SRY (sex determining region Y)-box 2 (Sox2), which was not altered by VPA treatment. Western analysis revealed hyperacetylation of histone H3 proteins in C17.2 cells after VPA treatment for 24 hr or 48 hr, suggesting involvement of an epigenetic mechanism in the observed gene induction by this drug. These findings support a role for VPA in modulating neurotrophic and differentiation factor expression, in keeping with its reported neuroprotective and neurodevelopmental effects.Neurotrophic factors are small proteins that play essential roles in the development and survival of neurons and the maintenance of neuronal synaptic function in the mature brain [1,2]. Disruption of neurotrophic factor levels or distribution has been implicated in several neurodegenerative diseases [3]. Transplantation of neural stem cells has been proposed as a promising therapeutic approach for replacement of lost cells and/or neurotrophic factors in neurodegenerative disorders [4]. The short-chain branched fatty acid, valproic acid (2-propylpentanoic acid), is used clinically as an anticonvulsant and mood-stabilizing drug. Recent reports have shown that VPA up-regulates the expression of diverse neurotrophic factors in the rat brain [5], and it induces neuronal differentiation in adult hippocampal progenitor cells [6]. Although the molecular mechanisms of VPA action are not fully understood, several protein kinase pathways have been suggested to serve as targets for this drug [7]. Moreover, VPA has been shown to inhibit the activity of histone deacetylases (HDACs), resulting in chromatin remodelling and changes in gene expression [8,9]. There is increasing evidence that HDAC inhibition with associated changes in gene expression, is a key mechanism in the multiple actions of VPA in the brain [7,10].Of interest, mouse C17.2 neural stem cells have b...

Human induced pluripotent stem cells (hiPSCs) hold great promise as a cell source for therapeutic applications and regenerative medicine. Traditionally, hiPSCs are expanded in two-dimensional static culture as colonies in the presence or absence of feeder cells. However, this expansion procedure is associated with lack of reproducibility and low cell yields. To fulfill the large cell number demand for clinical use, robust large-scale production of these cells under defined conditions is needed. Herein, we describe a scalable, low-cost protocol for expanding hiPSCs as aggregates in a lab-scale bioreactor.