| Background & ObjectiveMouse bone marrow-derived mesenchymal stem cells (MSCs) are adult stem cells that have the potential to undergo multi-lineage differentiation into multiple connective tissue cell types. They have a high capacity in self-renewal and proliferation. Under different conditions it can differentiate into mesoderm tissues, such as osteoblasts and cadiocytes, while it also can differentiate into the ectodermal tissues, such as neuron. Because of the convenience in obtaining, strong capacity of proliferation and large potential of differentiation, it can be widely used in clinical application. transplantation to treat neurological diseases has become an important domain of neuroscience research. The research about the differerntiation of MSCs into neurons and the application in the nervous systerm related diseases as a therapeutic tool have become an significant territory of neuroscience research. Unlike neural stem cells, MSCs differentiate into neural cells by a mechanism of transdifferentiation, but the regulatory factors involved remain poorly understood.microRNAs are members of the family of non-coding small RNAs and widespread in the biosphere. They can take part in a series of the life processes by regulating the expression of genome in the level of transcriptional, post-transcriptional, and so on. microRNA can form a complex regulation network though targeting multiple genes via many signaling pathways during the process of MSCs differentiation into neurons. microRNA-9 is expressed specifically in neurogenic areas of the brain, and plays an important role in neural stem cell self-renewal and differentiation. There is no report weather microRNA-9 can promt MSCs differentiation into neurons in vitro or not.As an important regulation pathway notch signaling pathway involves in stem cells differentiation and proliferation. The pathway is also found taking part in MSCs differentiation into neurons. MSCs can differentiation into neurons. However microRNA-9 plays an important role or there is a cross-talk between microRNA-9 and Notch signaling pathway are not clear.Therefore, this study will investigate the role and possible mechanisms of microRNA-9 and Notch signaling pathway in bone marrow mesenchymal stem cells (MSCs) differentiating into neurons.Materials and MethodologyBALB/C mice aged from six to eight weeks are selected to be the experimental animals and either sex. MSCs are isolated from both hindlimbs. And then cultured more than 10 passages for experiments. The cultured MSCs were divided into non-infected, infected (infected with microRNA-9-1-LV), and negative control (infected with FU-RNAi-NC-LV) groups.β-mercaptoethanol (β-ME) induces all groups cells differentiating into neurons. The expression of NSE, MAP-2, GFAP and Notch-1 were detected by immunocytochemical and western blot analyses. The expression of MAP-2 mRNA and notch-1 mRNA in MSCs were detected by RT-PCR. The viability of MSCs is detected by MTT.Results 1. microRNA-9 lentiviral vector can infect mice MSCs efficiently. The best infection efficiency and survival rate appeared when MOI was 20 and on 4th day. The efficiency of infection was up to 91.3%±4.2%. MTT displayed that there was not significantly different about the viability of MSCs.2. MSCs can differentiate into neurons induced byβ-ME and there is the best efficiency in the infected group. There is a higher expression of NSE and MAP-2 than the other two groups (P<0.05).3. There was a lower expression of Notch-1 in the infected group (P<0.05).Conclusion1. Up-regulated microRNA-9 promotes MSC neuronal differentiation.2. microRNA-9 might promote MSC neuronal differentiation by modulating the Notch signaling pathway. |
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