Bleomycin: A novel osteogenesis inhibitor of dental follicle cells via a TGF-β1/SMAD7/RUNX2 pathway
Bleomycin: A novel osteogenesis inhibitor of dental follicle cells via a TGF-β1/SMAD7/RUNX2 pathway
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DOI：
10.1111/bph.15281
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发表时间：
2020-12-13
影响因子：
7.3
通讯作者：
Zhao, Ji-Hong
中科院分区：
文献类型：
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作者：
Li, Zhi-Zheng;Wang, Hai-Tao;Zhao, Ji-Hong
背景与目的牙齿萌出是一个受牙囊（dental follicles，DF）调控的复杂过程.我们最近的研究发现，牙齿萌出后，博莱霉素注射到DF抑制。实验方法将人牙囊细胞（hDFCs）用博莱霉素或外源性TGF-β 1处理，或用负载SMAD 7的质粒或靶向SMAD 7的shRNA转染，然后进行成骨诱导测定和信号分析。用人新鲜DF组织和Wistar大鼠进一步证实博来霉素的功能。Key Results博来霉素降低hDFCs中RUNX 2和成骨基因的表达，降低成骨能力。TGF-β 1表达在博来霉素处理的hDFC中上调。外源性TGF-β 1的作用与博莱霉素在hDFC中的作用相似。此外，与SMAD 2/3相比，SMAD 7表达在博来霉素或TGF-β 1处理的hDFC中增加更多。SMAD 7的过表达同样显著降低了RUNX 2的表达和hDFC的成骨能力。SMAD 7的敲除显著减弱了博来霉素和TGF-β 1对hDFCs成骨能力和RUNX 2表达的抑制作用。最重要的是，TGF-β 1，SMAD 7，和RUNX 2的表达变化是相似的，在DF的大鼠和人类治疗的博莱霉素。结论和影响SMAD 7是一个负调节成骨分化的DFCs通过抑制RUNX 2的表达。博来霉素或TGF-β 1通过TGF-β 1/SMAD 7/RUNX 2途径抑制DFC的成骨分化。我们的研究结果可能有助于提高DFCs的成骨活性或抑制不良牙齿的萌出。
Background and Purpose Tooth eruption is a complicated process regulated by the dental follicles (DF). Our recent study discovered that tooth eruption was inhibited upon injection of bleomycin into DF. However, the mechanisms were unknown.Experimental Approach Human dental follicle cells (hDFCs) were treated by bleomycin or exogenous TGF-beta 1 or transfected by plasmids loading SMAD7 or shRNA targeting SMAD7, followed by osteogenesis induction assay and signalling analysis. Human fresh DF tissues and Wistar rats were used to further confirm bleomycin function.Key Results Bleomycin decreased expression of RUNX2 and osteogenic genes in hDFCs, reducing osteogenic capacity. TGF-beta 1 expression was up-regulated in bleomycin-treated hDFCs. The effects of exogenous TGF-beta 1 were similar to those of bleomycin in hDFCs. Additionally, compared to SMAD2/3, SMAD7 expression increased more in bleomycin- or TGF-beta 1-treated hDFCs. Overexpression of SMAD7 likewise significantly decreased RUNX2 expression and osteogenic capacity of hDFCs. Knockdown of SMAD7 markedly attenuated the inhibitory effects of bleomycin and TGF-beta 1 on osteogenic capacity and RUNX2 expression of hDFCs. Most importantly, changes in TGF-beta 1, SMAD7, and RUNX2 expressions were similar in the DF of rats and humans treated with bleomycin.Conclusion and Implications SMAD7 was a negative regulator of osteogenic differentiation in DFCs through suppressing RUNX2 expression. Bleomycin or TGF-beta 1 inhibited osteogenic differentiation of DFCs via a TGF-beta 1/SMAD7/RUNX2 pathway. Our findings might be beneficial for enhancing the osteogenic activity of DFCs or inhibiting the eruption of undesirable teeth.