| Neural stem cells (NSCs) appeared recently offer a good research model for neural development. Pluripotency and self-renewing are two basic attributes. The key problem is the proliferation and differentiation of NSCs. The NSCs of SVZa have become a good mold for neural development due to their following characteristics: The neural progenitor cells possess the final destinations to become neuron since it forms; It keeps the properties of undifferentiated neuronal phenotype during the migration; It begins to differentiate into terminally postmitotic interneuron, only in its final destination. As the mechanisms of proliferation and differentiation of NSCs of SVZa is still unclear, it is meaningful to do further research in this field.It is well known that growth factors and transcription factors play important roles in the neural development. The activation of intrinsic transcription procedure depends on the external signals. However, endogenetic factor plays more important roles than that of external signal in the differentiation of NSCs. It controls the competence of NSCs to the external signal during the neural development. Interaction between the external factors and the endogenous factors is the core of the differentiation of NSCs. It is important to clarify the interaction for neuronal inducement of neural development. BMP2, an important cytokine of TGF-beta superfamily, has complex regulatory roles in the control of proliferation and differentiation of NSCs. There are still none certain research about the functions of BMP2 on the proliferation and differentiation of NSCs of SVZa. MASH1, a proneuronal gene of basic helix-loop-helix transcription factors, is widely expressed in the neuronal progenitors of the CNS and PNS. The expression of MASH1 is restricted to the cells of the developing central and peripheral nervous systems. MASH1 has a role control function in the neuronal differentiation and determination of neuronal subtypes. But until now the molecular mechanism of MASH1 in the NSCs of the SVZa has been unclear. MASH1 is essential for autonomic neurogenesis. Bone morphogenetic protein 2 (BMP2) has been identified that it can induce the expression of MASH1 and promote autonomicneuronal differentiation of neural crest stem cells. Expression of endogenous MASH1 can be maintained by BMP2. Is there the same mechanism between BMP2 and MASH1 in the neuronal differentiation of NSCs of SVZ? What will happen if the NSCs of SVZa are induced by BMP2 and MASH1 at the same time? What is the relationship between BMP2 and MASH1 in the neuronal differentiation of NSCs of SVZa? First we investigated the effects of different concentrations of BMP2 on the proliferation and differentiation of the NSCs of the SVZaï¼›Then we constructed the plasmids which expression antisense and sense fusion proteins of MASH1 and EGFP,which acted as a live markerï¼›Immunofluorescence ,flow cytometry(FCM),MTT,liposome transfection were used to detect the effects of BMP2 and MASH1 on the proliferation and differentiation of NSCs of SVZa. We observed the mechanism by which BMP2 affects the proliferation and differentiation of the NSCs of SVZa. Further we studied the interactiont between BMP2 and MASH1. The results are as following: 1. Concentrations of BMP2 in the range of 1,5,10,20,100 ng/ml can promote the proliferation of NSCs of SVZa, particularly 5 ng/ml BMP2 promotes proliferation significantly. The promotion effect becomes weaker with the increase of concentrations of BMP2 (5-100ng/ml).2. Concentrations of BMP2 in the range of 1,5,10,20,100 ng/ml promote neuronal differentiation, particularly 10 ng/ml BMP2 promotes neuronal differentiation significantly. 20-100ng/ml BMP2 promoted neuronal differentiation too, but the neuronal differatiation rate drops down, as compared with the 1-10ng/ml groups.3. MASH1 can promote neuronal differentiation of NSCs of SVZa. Antisensive MASH1 can block neuronal differentiation of NSCs of SVZa.4. The neuronal differentiation ratio of NSCs of SVZa under different conditio... |
