Effects Of ?-smooth Muscle Actin On Neural Stem Cells Activation

Objective: The purpose of this project is to explore the relationship between ?-smooth muscle actin expression and neural stem cells activation and its underlying mechanisms.Methods: NSCs was cultured and transfected with ACTA2 siRNA,then we identificated the efficiency.NSCs was divided into blank control group(Control),negative control group(Scramble),solvent control group(Vehicle),ACT2 knockdown group(ACTA2siRNA).The differences in NSCs migration,proliferation,and differentiation among the groups were observed.The Rho family(RhoA,Rac1,Cdc42)protein expression differences were detected;Y27632,Rho-related protein kinase(ROCK)inhibitors,was used to treat the NSCs which were knockdown ACTA2 and the migration of NSCs was observed.Results: 1.The primary NSCs we cultured have great ability of NSCs maintenance and multiple differentiation potential.And ?-SMA could express in NSCs obviously,ACTA2 siRNA significantly down-regulated the expression of ?-SMA in NSCs.2.Ki67-positive cells were decreased in ACTA2 siRNA group,NeuN expression was decreased,GFAP and Olig2 expression was increased in the ACTA2 siRNA group,compared to control,scramble and vehicle groups,there was statistical difference(p <0.01).3.The cell outgrowth distance migrating from neurospheres were obviously decreased in ACTA2 siRNA group,the percentage of filopodia formation,the average number of leading processes and secondary branches were also evidently decreased in ACTA2 siRNA group,compared to control,scramble and vehicle groups,there was statistical difference(p <0.01).4.The expression of RhoA was increased and Rac1 was decreased in the ACTA2 siRNA group,compared to control,scramble and vehicle groups,there was statistical difference(p<0.01).There was no significant difference in CDC42 expression between the groups.The increased level of RhoA was higher than the decreased level of Rac1.NSCs were knocked down ACTA2 and treated with Y27632,the expression of active RhoA was increased in ACTA2 siRNA+Y27632 group compared to control and vehicle groups,and expression of active RhoA in siRNA+Y27632 group was partially reduced than ACTA2 siRNA group,there was statistical difference(p <0.01).Compared to ACTA2 siRNA group,the migrationdistance of NSCs in the ACTA2 siRNA+Y27632 group was increased,the percentage of filopodia formation,the average number of leading processes and secondary branches also increased,there was statistical difference(p <0.01).Conclusion: The expression of ?-SMA decreasing inhibits the proliferation of NSCs,and inhibits NSCs differentiation into neurons,promotes NSCs differentiation into glial,may regulate the polymerization of actin filaments through the Rho/ROCK pathway to inhibit the migration of NSCs to the injured lesion,which is not conducive to neural network repair after brain injury.