Transplantation Of Neurogenin2 Transfected Mesenchymal Stem Cells Via Plentivirus As A Neuroprotective Therapy For Ischemic Stroke In Rats

Background and objectionMesenchymal stem cells (MSCs) with self-renewal and multilineage developmental capacities are a promising cell source for the replacement strategy for the patients with CNS injury such as cerebral infarction because neurogenesis rarely occurs after CNS injury. The possible neuroprotective effect of MSCs has received the attention progressively. However more studies reported that only minor proportions of donor MSCs appeared to be viable in the host brains, and the long-term efficacy of neural transdifferentiation accompanied by long-term cell survival was very lower.Neurogenin2 (Ngn2) is a member of the transcription factors belonging to the basic Helix-Loop-Helix (bHLH) gene family known to regulate crucial developmental processes in various mammalian tissues. Neural bHLH transcription factors such as Neurogenin 2 (Ngn2), Mash1 are expressed in both the central and the peripheral nervous systems during development not only to promote early neuronal differentiation but also to specify the neural cell fate.In the present study, we transfected Ngn2 into mesenchymal stem cells via plentivirus and established rats'model of stroke undergoing MCAO. In vitro we investigated whether the Ngn2 has the neurogenic potential in converting pluripotent stem cells such as MSCs into neural cells. We also investigated whether the transplantation of Ngn2-MSCs can transdifferentiate into neural cells in vivo, repair CNS injury caused by the stroke or promote neurological function recovery in rats. Methods1,The recombinant lentiviruses Plenti-GFP-Ngn2 which carried Ngn2 and GFP gene were used to infect mesenchymal stem cells. Expression of Ngn2 protein expressions was dectected via western blotting analysis.2,To invest the ability neural transdifferentiation of the Neurogenin2 transfected Mesenchymal Stem Cells (Ngn2-MSCs), immunocytochemistry was utilized to detect the markers of neural cells such as NSE,Map2 without any induction in vitro.3,Ngn2-MSCs or GFP-MSCs were transplanted into rats'striatum those were subjected to the middle cerebral artery occlusion (MCAO) through stereotactic apparatus. These cells'survival, migration and transdifferentiation were studied in vivo.4,TTC stain, TUNEL stain were used respectively to detect the Relative infarct volume(RIV), the number of the apoptotic cells of the ipsilateral cortex, and mNSS behavior tests were utilized to observe the dynamic state of the rats'neurological function which was suffered MCAO after 2 days and 2,4,6,8 weeks.Results1,The recombinant lentiviruses which carried Ngn2 could transfect and deliver Ngn2 gene into mesenchymal stem cells and Ngn2 can be expressed efficiently in mesenchymal stem cells.2,Ngn2-MSCs appeared typical morphological neuronal traits and expressed NSE,MAP2 positively in vitro.3,Ngn2-MSCs can survival, migration and neural transdifferentiation effectively in vivo.4,The Relative infarct volume(RIV), the number of apoptotic cells of the ipsilateral cotex, and the scores of mNSS behavior tests in the groups of the Ngn2-MSCs transplantation are significantly improved compared to the contrast groups. Conclusions1, Neurogenin2 transfected mesenchymal stem cells (Ngn2-MSCs) can transdifferentiate into neural cells without any induction in vitro.2, Transplantation of Ngn2-MSCs can promote the ischemic neural cells repairing and neurological function recovery in the rat model of the stroke.