A novel xenogeneic co-culture system to examine neuronal differentiation capability of various adult human stem cells

Background

Targeted differentiation of stem cells is mainly achieved by the sequential administration of defined growth factors and cytokines, although these approaches are quite artificial, cost-intensive and time-consuming. We now present a simple xenogeneic rat brain co-culture system which supports neuronal differentiation of adult human stem cells under more in vivo-like conditions.

Methods and Findings

This system was applied to well-characterized stem cell populations isolated from human skin, parotid gland and pancreas. In addition to general multi-lineage differentiation potential, these cells tend to differentiate spontaneously into neuronal cell types in vitro and are thus ideal candidates for the introduced co-culture system. Consequently, after two days of co-culture up to 12% of the cells showed neuronal morphology and expressed corresponding markers on the mRNA and protein level. Additionally, growth factors with the ability to induce neuronal differentiation in stem cells could be found in the media supernatants of the co-cultures.

Conclusions

The co-culture system described here is suitable for testing neuronal differentiation capability of numerous types of stem cells. Especially in the case of human cells, it may be of clinical relevance for future cell-based therapeutic applications.

Towards the development of a pragmatic technique for isolating and differentiating nestin-positive cells from human scalp skin into neuronal and glial cell populations: generating neurons from human skin?

Nestin+ hair follicle-associated cells of murine skin can be isolated and differentiated in vitro into neuronal and glial cells. Therefore, we have asked whether human skin also contains nestin+ cells, and whether these can be differentiated in vitro into neuronal and/or glial cell populations. In this methodological pilot study, we show that both are indeed the case - employing purposely only very simple techniques for isolating, propagating, and differentiating nestin+ cells from normal human scalp skin and its appendages that do not require selective microdissection and tissue compartment isolation prior to cell culture. We show that, it is in principle, possible to maintain and propagate human skin nestin+ cells for extended passage numbers and to differentiate them into both neuronal (i.e. neurofilament+ and/or PGP9.5+) and glial (i.e. GFAP+, MBP+ and/or O4+) cell populations. Therefore, human scalp skin can serve as a highly accessible, abundant, and convenient source for autologous adult stem cell-like cells that offer themselves to be exploited for neuroregenerative medicine purposes.

Adult pancreatic stem/progenitor cells spontaneously differentiate in vitro into multiple cell lineages and form teratoma-like structures

Cells isolated from pancreas have a remarkable potential for self-renewal and multilineage differentiation. We here present a comprehensive characterisation of stem/progenitor cells derived from exocrine parts of the adult rat pancreas. Using purified cells from either single colonies or even single-cell clones, we specifically demonstrate: (i) the cells contain the typical stem/progenitor cell markers alkaline phophatase, SSEA-1, Oct-4, CD9, Nestin, Pax6, CD44, a-Fetoprotein and Brachyury, demonstrated by immunocytochemistry and RT-PCR; (ii) the cells have the potential to differentiate into lineages of all three germ layers in vitro; (iii) a clonal analysis revealed that even cell lines derived from a single cell have stem/progenitor cell properties such as self-renewal and spontaneous differentiation into various cell lineages; (iv) the cells have the propensity to form three-dimensional, teratoma-like structures in vitro, which contain cells of different lineages; and (v) external stimuli can activate the generation of certain cell types. For instance, cells treated with retinoic acid show an increased expression of alpha-smooth muscle actin. These results suggest that exocrine glands, such as pancreas may be a potential source of adult stem/progenitor cells, suitable for cell therapy of degenerative diseases.