DLK1对人牙髓干细胞增殖和成牙本质分化的影响

Effect of delta-like 1 homologue on the proliferation and dontoblastic differentiation in human dental pulp stem cells

目的研究DLK1在人牙髓干细胞(hDPSCs)增殖分化中的作用。方法用免疫组织化学分析法来检测小鼠上颌第一磨牙中DLK1的表达。构建重组慢病毒使DLK1在hDPSCs中稳定过表达,用CCK8法和Ed U核素渗入法分别检测hDPSCs的细胞活力和增殖;hDPSCs进行成牙本质细胞向分化诱导后,通过ALP活性分析、ALP和茜素红染色,以及ALP、DSPP、DMP1等矿化相关基因的表达,研究hDPSCs的成牙本质细胞向的分化。结果 DLK1在小鼠上颌第一磨牙的成牙本质细胞和牙髓细胞中高表达,而且正常hDPSCs在成牙本质细胞向分化诱导14 d后,ALP蛋白水平增长1.6倍,DSPP增长1.16倍,DMP1增长1.42倍,DLK1增长1.54倍。hDPSCs中过表达DLK1后,相比于对照组增加了1.7倍,显著促进了细胞增殖,却抑制了其成牙本质细胞向分化。结论 DLK1在牙齿发育中发挥重要作用,DLK1过表达促进hDPSCs的增殖,但抑制其成牙本质细胞向分化。

Objective To investigate the functions of DLK1 in the proliferation and differentiation of human dental pulp stem cells （hDPSCs）. Methods Immunohistochemical analysis was used to determine the expression of DLK1 in the mouse first maxillary molar. Recombinant lentivirus was constructed to overexpress DLK1 stably in hDPSCs. The cell viability and proliferation of hDPSCs were ex- amined by CCK8 and EdU incorporation assay, respectively. The odontoblastic differentiation of hDPSCs was determined by detection of ALPase activity assay, ALP and alizarin red staining and the expression of mineralization-related genes including ALP, DSPP and DMP1. Result DLK1 highly expressed in the odontoblasts and dental pulp cells on the first maxillary molar. The expression level of ALP,DSPP, DMP-1 and DLK1 increased significantly after the odontoblastic induction of hDPSCs. Compared with the control group, the expression level of ALP increased by 1.6 times, DSPP increased by 1.16 times, DMP1 increased by 1.42 times and DLK1 in- creased by 1.54 times. DLK1 over expression increased the proliferation ability of hDPSCs and inhibited odontoblastie differentiation of hDPSCs. Compared with the control group, hDPSCs increased by about 1.7 times with the over expression of DLK1. Conclusions The proliferation of hDPSCs is promoted after DLK1 over expression. DLK1 inhibits the odontoblastic differentiation of hDPSCs.