| Parkinson's disease (PD) is a degenerative disorder characterized by a loss of midbrain dopamine (DA) neurons with a subsequent reduction in striatal DA. Medical treatment founctioned temporarily and accompanied with a side-effect. Embryonic stem cells (ESCs) , with the capacity to proliferate indefinitely , as well as pluripotency of three germ layers, hold great potential on stem cell therapy of PD. Since the grafting of naive hESC in animal model of PD, whilst showing some functional recovery, is also associated with a high risk of the animals developing teratomas.Hence,ESCs—derived neural precursor cells (NPC) might be ideal for PD therapy, as they kept the neural differention and proliferation ablity of ESCs', both in vitro and in vivo.In this study,we differentiated mouse ebryonic stem cells into NPC ,using a serum-free,low densiy and fast induction protocol.Immunofluroscence and RT-PCR both confirmed the high ratio of nearly 100% Nestin-positive of NPCs.After transplanted for 2 weeks,we detected the tyrosine hydroxylase(TH) -positive cells in the transplanted site of Parkinsonian mouse model.At the same time,HPLC showed that the DA level were increased accordingly,and there is significant difference (P < 0.05)between NPC and negative PBS transplanted animals, however,the DA levels decreased by 4 weeks.Finally, it should be noted 18.75% of transplanted animals developed terotomas in the brain,and which were demonstrated consisting of three germ layer cells.These results indicated that,transplanted NPC did restore DA neuron and DA levels in PD animal,but the pure NPC still fomed teratomas,which possibly denoted the close correlattion beween NPC(derived from current induction protocol ) and ESCs ,further study should be designed to clarify the developmental status of the NPC,hoping to find the curative NPC for PD.Mouse embryonic stem cells (mESCs) pioneered in the newly emerging stem cell research. The traditional derivation and culture of mESCs were based on the combination of embryonic fibroblasts (MEFs) with exogenous leukemia inhibitory factor(LIF). However, rapid senescence of MEFs and expensive price of LIF hampered the generalization of mESCs research to a much degree. Hereby,we present a novel exogenous LIF-free culture system ideal for the generalization of mESCs .By now,the mESCs cultured on RSFs ( mESCs-RSFs ) have been subcultured over 10 generations without exogenous LIF , and mESCs -RSFs did not lose their specific markers on gene and protein levels. The in vivo and in vitro differential potential within were intactly preserved .RT-PCR identified the high level expression of LIF and WNT3A in RSFs which may account for the exogenous LIF-free maintainence of mESCs.Moreover,this exogenous LIF-free feeder system was verified to be microbiological quality assured by Electron Transmission Microscopy.Fibroblasts and mesenchymal stem cells (MSCs) are mesodermal in status and have been isolated from various tissues. However, unlike fibroblasts, MSCs were demonstrated to possess broad differentiation capacities.Recent studies suggested the difficulty discriminating fibroblasts from MSCs based on phenotype (morphology and specific protein markers) or growth capacity.Therefore,in this study we tried to investigate the multipotential of RSFs.With classic induction paradigm,RSFs manifested the multilineage potential of osteoblast,adipocyte and smooth muscle cell ,both in special staining and gene expression.Furthermore ,RSFs also transdifferentiation into hepatocyte indicated by PAS staining.In conclusion , our work demonstrated that RSFs might be a kind of multifunctional cell type.They displayed powerful ESC maintenance and multipotential as well,both of which have important clinical implications for cell-based therapies .
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