In Vitro Differentiation of Human Placenta Derived Mesenchymal Stem Cells into Dopaminergic Cells

Mesenchymal stem cells (MSCs) constitute an interesting cellular source to promote brain regeneration after Parkinson diseases. Compared with other stem cells, MSCs derived from human placenta have significant advantages and greater potential for immediate clinical application. The aim of this study was to investigate whether human placenta mesenchymal stem cells(hpMSCs) could be induced to differentiate into dopaminergic cells in vitro. MSCs from human placenta were isolated by digest and density gradient fractionation. Cell surface glycoproteins of these hpMSCs were analyzed by flow cytometry. These hpMSCs were cultured under conditions promoting differetiation to osteoblasts and adipocytes. Using a cocktail that includes basic fibroblast growth factor(bFGF), all trans retinoic acid(RA), ascorbic acid(AA),3-isobutyl-1-methylxanthine(IBMX), hpMSCs were induced in vitro to become dopamine (DA) neurons. The expression of mRNA of nestin and tyrosine hydroxylase(TH) genes known with significant associated with dopaminergic neuron differentiation from the induced hpMSCs was assayed by RT-PCR. The expression of proteins of nestin, dopamine transporter(DAT), neuronal nuclear antigen(NeuN) and TH was determined by immunofluorescence. The synthesized and secreted DA by induced hpMSCs was determined by ELISA. We found that hpMSCs exhibited fibroblastoid morphology. Flow cytometric analyses showed that the hpMSCs were positive for CD44 and CD29, negative for CD34, CD45, CD106 and HLA-DR. Moreover, they could be induced into adipocytes and osteocytes. When hpMSCs were induced with bFGF, RA, AA, IBMX, the MSCs showed a change of neuronal-like cells in morphology. The induced cells express nestin and TH mRNA. The induced MSCs also express nestin, DAT, NeuN, and TH protein. ELISA showed the induced MSCs synthesized and secreted DA. Our results suggest that MSCs from human placenta have the ability to differentiate into dopaminergic cells in vitro.