1 Department of Neurobiology, Duke University Medical Center and Howard Hughes Medical Institute, P.

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Abstract Full-Text PDF Full-Text HTML Full-Text ePUB Linked References How to Cite this Article Stem Cells International Volume 2014 (2014), Article ID 182737, 14 pages http://dx.doi.org/10.1155/2014/182737
1 Department of Neurobiology, Duke University Medical Center and Howard Hughes Medical Institute, P.O. Box 3209, Durham, NC 27710, USA 2 Instituto de Células Madres SUAGM, Sistema Universitario Ana G. Méndez, P.O. Box 21345, San Juan, PR 00928-1345, USA 3 Max-Delbrück Center for Molecular Medicine, Berlin Brandenburg School for Regenerative streatham hill vets Therapies, Hochbau 31.1, 13125 Berlin, streatham hill vets Germany 4 Department of Biology, Boston University, streatham hill vets LSEB 406, Boston, MA 02215, USA 5 Neurotransgenic streatham hill vets Laboratory, Duke University Medical Center, P.O. Box 3209, Durham, NC 27710, USA
Pluripotent stem cells have the potential streatham hill vets to become any cell in the adult body, including neurons and glia. Avian stem cells could be used to study questions, like vocal learning, that would be difficult to examine with traditional mouse models. Induced pluripotent stem cells (iPSCs) are differentiated cells that have been reprogrammed to a pluripotent stem cell state, usually using inducing genes or other molecules. We recently succeeded in generating avian iPSC-like cells using mammalian genes, overcoming a limitation in the generation and use of iPSCs in nonmammalian species (Rosselló et al., 2013). However, there were no established optimal cell culture conditions for avian iPSCs to establish long-term cell lines and thus to study neuronal differentiation in vitro . Here we present an efficient method of maintaining chicken iPSC-like cells and for differentiating them into action potential generating neurons. 1. Introduction
Pluripotent stem cells are undifferentiated cells that have the potential to become any cell type in the adult body. They have two main hallmarks. First, unlike differentiated somatic cells, stem cells have the ability to self-renew and proliferate. Second, they have the ability to differentiate into somatic cells with drastically different properties. streatham hill vets There are currently two main methods that can be used to derive or create stem cells in vitro . The first is to isolate embryonic stem cells (ESC) from early embryos. The second is to induce pluripotent stem cells (iPSCs) from somatic cells such as fibroblasts, first demonstrated possible with a combination of four transcription factors: Oct4, Sox2, Klf4, and c-myc [ 1 ].
Though both ESCs and iPSCs can differentiate into somatic cells, there are differences between the two types of stem cells that still elicit concerns of whether iPSCs could fully recapitulate the characteristics of pluripotent streatham hill vets ES cells. These include iPSCs genetic alterations streatham hill vets from integration of the viral vector streatham hill vets containing the reprogramming transcription factors into host genes [ 2 ] and epigenetic modifications such as DNA methylation and histone activation [ 3 ]. Even after reprogramming, iPSCs still retain memory of the tissue that they were derived streatham hill vets from (although possibly limited to early passages), which might restrict their differentiation into other types of cells [ 4 , 5 ]. Sometimes the differentiation restriction decreases as the number of passages streatham hill vets of iPSCs increases streatham hill vets [ 6 ]. Thus, because of possible differences between ESCs and iPSCs, it is important streatham hill vets to verify streatham hill vets the differential and developmental properties of any line of iPSCs generated. streatham hill vets
Birds are important organisms for studying development, including neural development [ 7 ]. One of the advantages streatham hill vets to using chicken as a model organism is the ability to monitor its embryo development in ovo . However, a limitation of studies with birds is that there are very few cell lines available for studying cell function. Thus, one of our goals has been to create avian stem cells that could be used to study neuronal function. Towards streatham hill vets this goal, we recently were successful at using the mammalian homologs of the iPSC inducing transcription factors to induce partial iPSC-like cells across the animal kingdom, in birds, fish, and Drosophila [ 8 ]. We were able to show in vivo incorporation and differentiation streatham hill vets of the cells in birds and fish but were not able to obtain stable cell lines that survived many passages. Here we developed novel media conditions that allowed us to maintain these same avian cells well past 20 passages, and we were able to differentiate them into neurons in vitro . 2. Materials and Methods