Figure 1.
Characterization of mRNA-expression in skin-derived and glandular stem cells.
SDSC, PDSC and PSC were analyzed with regard to their transciptome by quantitative RT-PCR and capillary gel electrophoresis. Hereby they were shown to consistently transcribe markers for stemness, proliferation (Ki67) as well as all three germ layers (with exception for S100β in the case of the PDSC).
Figure 2.
Immunocytochemical characterization of skin- and gland-derived stem cells concerning their stemness.
SDSC, PDSC and PSC generally express the stem cell markers Nestin, Sox 2 and Oct 4 as well as marker proteins for protein synthesis (Vigilin) and proliferation (Ki67). Nuclei were counterstained with DAPI (blue).
Figure 3.
Immunocytochemical characterization of skin- and gland-derived stem cells concerning their differentiation capability.
The used stem cell lines (SDSC, PDSC, PSC) spontaneously differentiate in vitro and, in the course of this differentiation, express marker proteins for the ectodermal (NF, GFAP, CK18, panCK) and mesodermal (α-SMA) germ layer. Nuclei were counterstained with DAPI (blue).
Figure 4.
The effect of brain co-culture on the protein expression of skin-derived and glandular stem cells.
Co-cultivation with rat brain biopsies led to comparable changes in the expression of some structure proteins in all three human stem cell populations. In the case of Nestin-expressing cells a distinctive decrease by up to one third could be detected, with the slight exception of the SDSC (A–F). The percentage of NF-positive cells increased in all populations up to 4-fold, accompanied by the general exhibition of an elongated morphology resembling uni- and bipolar neurons (G–L; arrows). α-SMA-positive cells decreased in number and/or showed a visible degradation of the actin filaments (M–R). Nuclei were counterstained with DAPI (blue). Blue bars represent the total cell count (via DAPI) in each image, red and green bars the relative amount of positively stained cells.
Figure 5.
Co-culture-induced alterations in the expression of neural genes by skin-derived and glandular stem cells.
The transcriptional activity of brain biopsy co-cultured stem cells was analyzed by quantitative PCR and set in relation to untreated control approaches (representing the value ‘1’). Stimulation resulted in relatively minor variations of the stem cell marker Nestin, whereas the expression of NF(L) and NF(M) was enhanced in all populations and thereby increased up to the factor 18.8 and 17.6 in PSCs, respectively. For the expression of NF(H) almost no alteration was observable. In the case of β III Tubulin some reduction in the mRNA expression level was detectable for SDSC and PDSC; for PSC a slight increase was measurable. The mRNA level of the neuron-specific enzymes PGP9.5 and neuron specific enolase (NSE) was increased after stimulation in all stem cell populations up to the 19.1-fold for NSE in PSC.
Figure 6.
Neuron-like development in skin- and gland-derived stem cells during co-culture.
An immunocytochemical staining revealed the co-localization of the neuroprogenitor marker Nestin and the neuronal cell marker Neurofilament in co-culture stimulated SDSC, PDSC and PSC (A). Furthermore, the establishment of axon-like cell processes with lengths up to 450 µm could be detected after co-cultivation (B).
Figure 7.
Detection of secreted growth factors via microarray.
Supernatants of co-cultures and controls were tested for the presence of growth factors via a microarray-based technique (A). The processed arrays were semi-quantitatively analyzed by fluorescence, whereby representative images for every approach are shown (B). Growth factors that were found in at least four of five experiments were comparatively described in their expression based on the fluorescence signals (blue = weak/+; green-yellow = moderate/++; red-white = strong/+++) (C).