BACKGROUND:Previous studies have demonstrated that the cannabinoid type Ⅰ receptor can enhance the proliferation and neural differentiation of neural stem cells and mesenchymal stem cells.Moreover,cannabinoid type Ⅰ also governs the proliferation and mineralization capacity of human apical papilla stem cells.However,there are relatively few investigations concerning the impact of cannabinoid type Ⅰ overexpression on the neural differentiation of human apical papilla stem cells.OBJECTIVE:To investigate the effect of cannabinoid type Ⅰ on neural differentiation of human apical papilla stem cells in vitro.METHODS:Healthy third molars with immature root tips that need to be removed for orthodontic treatment were collected,and human apical papilla stem cells were isolated and cultured by tissue block method combined with enzyme digestion method.Cannabinoid type Ⅰ gene was introduced into human apical papilla stem cells by lentivirus-mediated transfection technique.A blank control group,a negative control group,and cannabinoid type Ⅰ overexpression group were set up.The transfection effect of overexpression of cannabinoid type Ⅰ lentivirus on human apical papilla stem cells was verified by Western Blot.The control group,negative control group,cannabinoid type Ⅰ overexpression group and cannabinoid type Ⅰ overexpression+AM251(cannabinoid type Ⅰ receptor antagonist)group were set up.Cell proliferation was detected by CCK-8 assay at 1,5,and 10 days after neural induction.On day 10 of neural induction,the expression levels of TH,NeuroD-1,and NCAM1 genes were detected by qRT-PCR,and the protein expression levels of Nestin and TUBB3 were detected by immunofluorescence.RESULTS AND CONCLUSION:(1)Compared with the blank control group and the negative control group,the expression of cannabinoid receptor Ⅰ protein in the cannabinoid receptor Ⅰ overexpression group was significantly increased,and the difference was significant(P＜0.05).(2)Compared with the blank control group and the negative control group,the proliferation ability of human apical papilla stem cells in the cannabinoid type Ⅰ overexpression group was the strongest at 5 and 10 days after neural induction(P＜0.05).(3)Compared with the blank control group and the negative control group,the mRNA expression of NeuroD-1,NCAM1,and TH in the stem cells of the human apical papilla in the cannabinoid type Ⅰ overexpression group was significantly increased,and the fluorescence intensity of Nestin and TUBB3 was significantly enhanced(P＜0.05).(4)Compared with the cannabinoid type Ⅰ overexpression group,the proliferation ability,mRNA expression level of NeuroD-1,NCAM1,and TH,as well as the fluorescence intensity of Nestin and TUBB3,were significantly decreased in the cannabinoid type Ⅰ overexpression+AM251 group(P＜0.05).These findings conclude that overexpression of cannabinoid type Ⅰ promoted the proliferation and neural differentiation of human apical dentin papilla stem cells.

BACKGROUND:Previous studies have demonstrated that the cannabinoid type Ⅰ receptor can enhance the proliferation and neural differentiation of neural stem cells and mesenchymal stem cells.Moreover,cannabinoid type Ⅰ also governs the proliferation and mineralization capacity of human apical papilla stem cells.However,there are relatively few investigations concerning the impact of cannabinoid type Ⅰ overexpression on the neural differentiation of human apical papilla stem cells.OBJECTIVE:To investigate the effect of cannabinoid type Ⅰ on neural differentiation of human apical papilla stem cells in vitro.METHODS:Healthy third molars with immature root tips that need to be removed for orthodontic treatment were collected,and human apical papilla stem cells were isolated and cultured by tissue block method combined with enzyme digestion method.Cannabinoid type Ⅰ gene was introduced into human apical papilla stem cells by lentivirus-mediated transfection technique.A blank control group,a negative control group,and cannabinoid type Ⅰ overexpression group were set up.The transfection effect of overexpression of cannabinoid type Ⅰ lentivirus on human apical papilla stem cells was verified by Western Blot.The control group,negative control group,cannabinoid type Ⅰ overexpression group and cannabinoid type Ⅰ overexpression+AM251(cannabinoid type Ⅰ receptor antagonist)group were set up.Cell proliferation was detected by CCK-8 assay at 1,5,and 10 days after neural induction.On day 10 of neural induction,the expression levels of TH,NeuroD-1,and NCAM1 genes were detected by qRT-PCR,and the protein expression levels of Nestin and TUBB3 were detected by immunofluorescence.RESULTS AND CONCLUSION:(1)Compared with the blank control group and the negative control group,the expression of cannabinoid receptor Ⅰ protein in the cannabinoid receptor Ⅰ overexpression group was significantly increased,and the difference was significant(P＜0.05).(2)Compared with the blank control group and the negative control group,the proliferation ability of human apical papilla stem cells in the cannabinoid type Ⅰ overexpression group was the strongest at 5 and 10 days after neural induction(P＜0.05).(3)Compared with the blank control group and the negative control group,the mRNA expression of NeuroD-1,NCAM1,and TH in the stem cells of the human apical papilla in the cannabinoid type Ⅰ overexpression group was significantly increased,and the fluorescence intensity of Nestin and TUBB3 was significantly enhanced(P＜0.05).(4)Compared with the cannabinoid type Ⅰ overexpression group,the proliferation ability,mRNA expression level of NeuroD-1,NCAM1,and TH,as well as the fluorescence intensity of Nestin and TUBB3,were significantly decreased in the cannabinoid type Ⅰ overexpression+AM251 group(P＜0.05).These findings conclude that overexpression of cannabinoid type Ⅰ promoted the proliferation and neural differentiation of human apical dentin papilla stem cells.