Artikel
Neuronal cell viability is promoted by paracrine factors released from endothelial progenitor cells
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Veröffentlicht: | 4. Juni 2012 |
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Gliederung
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Objective: There is growing evidence that stem cells exert regenerative actions by means of paracrine factors. In the present study we tested the hypothesis that soluble factors secreted by cultured endothelial progenitor cells (EPC) may support neuronal cell functions and survival.
Methods: EPC were isolated from peripheral blood of healthy human donors by gradient centrifugation. Cells were cultured in hypoxic conditions (1.5% O2) to stimulate the secretion of growth factors. Primary cultures from rat embryonic (E14) ventral mesencephalon, striatum and cortex were grown for one week and chronically treated with EPC derived conditioned medium (CM). The effect of EPC-CM was monitored by immunocytochemical analyzes for neuronal markers including β-III-tubulin, GABA, Neuronal Nuclei (NeuN), and tyrosine hydroxylase (TH) as well as for a marker of microglial cells (Iba1). Cell viability was measured by means of the MTT assay.
Results: Incubation of primary cultures with EPC-CM resulted in an overall augmented viability compared to controls. This effect was associated with significantly increase in TH-ir cell densities in ventral mesencephalic as well as NeuN-ir and GABA-ir cell densities in the striatal cultures, respectively. Similarly, the number of β-III-tubulin expressing cells was significantly increased in cortical cultures exposed to EPC-CM. Most strikingly, treatment of cultures with EPC-CM resulted in a marked increase of number of microglial cells. Reducing the number of cortical microglial cells only partially attenuated the effects EPC-CM.
Conclusions: Our findings indicate that EPC play a substantial role for developing brain tissues through remarkable paracrine actions. The effects on neuronal cells are likely both directly governed by EPC-CM as well as secondary by the microglia.
This work was supported by SNF-NRP63.