BACKGROUND:How to improve the proliferation of human dental pulp stem cells(hDPSCs)in vitro is of great importance in regenerative medicine. OBJECTIVE: To investigate the effect of TAZ, a transcriptional coactivator, on the proliferation of hDPSCs and its potential mechanisms. METHODS:hDPSCs were isolated from human dental pulps and cultured in vitro.The expression of TAZ in hDPSCs was detected by immunofluorescence method. Then, we knocked down the expression of TAZ in hDPSCs, and the proliferation of hDPSCs was measured by MTT and BrdU kit analysis respectively. The levels of CTGF and Cry61, which are the downstream target genes of TAZ, were detected by RT-qPCR and western blot assay. We also investigated the effect of TAZ on the levels of transforming growth factor-β (TGF-β) signaling proteins, Smad3 and Smad 4 by using western blot. RESULTS AND CONCLUSION: TAZ protein was expressed in hDPSCs. After the transfection by siTAZ for 24 hours, the mRNA and protein levels of TAZ were both significantly decreased. After the transfection by siTAZ for 24 and 48 hours, the proliferation of hDPSCs was obviously inhibited. Meanwhile, the mRNA and protein levels of CTGF and Cry61 were decreased by siTAZ transfection. The further research showed that TAZ silence also inhibited the expression of Smad3 and Smad 4, which belonged to the TGF-β signaling pathway. To conclude, TAZ may modulate the proliferation of hDPSCs through regulating the expression of CTGF and Cry61, and TGF-β-dependent signaling pathways may be involved in this regulation.%背景:如何提高人牙髓干细胞体外增殖能力对于再生医学具有重要的意义.目的:探讨转录共激活因子TAZ对人牙髓干细胞增殖的影响和潜在的作用机制.方法:分离培养人牙髓干细胞,利用细胞免疫荧光法检测TAZ在人牙髓干细胞中的表达;用siRNA敲减TAZ表达后,通过MTT法和BrdU细胞增殖试剂盒检测人牙髓干细胞增殖情况;通过实时荧光定量PCR和蛋白免疫印迹法检测TAZ下游靶基因CTGF和Cry61的表达;蛋白免疫印迹法进一步检测TAZ对TGF-β通路蛋白Smad3和Smad4表达的影响.结果与结论:①人牙髓干细胞表达TAZ蛋白;②细胞转染siTAZ 48 h后,TAZ mRNA和蛋白表达水平均显著降低;转染siTAZ 24 h和48 h后,人牙髓干细胞增殖速度均显著下降;③细胞转染siTAZ后,TAZ下游靶基因CTGF和Cyr61 mRNA和蛋白表达均受到抑制;④细胞转染siTAZ后,TGF-β通路蛋白Smad3和Smad4的表达水平降低;⑤以上结果表明,TGF-β依赖性信号通路可能参与了TAZ调节CTGF和Cyr61表达,从而调控人牙髓干细胞的增殖.
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