MiR-214靶向作用Osterix调控成牙骨质细胞分化的研究

Osterix(Osx), a transcription factors, plays an import role in development and mineralization of bone. Our last NSFC showed that Osx regulated the development of cementum. Moreover, our recent previous study also demonstrated that miR-214 was decreased significantly in the process of mineralization of cementoblast. In this project we want to study how miR-214 regulates the differentiation of cementoblast by targeting Osx. On one hand, we used mimic or inhibitor of miR-214 and investigated the effect of miR-214 on cementoblast differentiation by gain- and loss-of-function experiments; at the same time, bioinformatic analysis combined with luciferase reporter assay demonstrated if Osx is the targeted gene during the differentiation of cementoblast of miR-214; besides, we tried to confirm the change of wnt. On the other hand, we generated lentivirus vector of miR-214 over-expression or inhibition, and investigated the development of cementum by injecting them into Osx Tg and WT mice. Collectively, this project proposed that miR-214 is a novel regulator of Sp7 during the cementoblast differentiation, which would guide a great direction of cementum regeneration.

我们今年将结题的国家自然基金项目研究表明Osx调控牙骨质的发育形成。同时我们利用microRNA芯片研究发现在小鼠成牙骨质细胞矿化诱导中，miR-214的表达显著下调。为此本课题主要研究miR-214如何靶向作用Osx调控成牙骨质细胞的分化。我们一方面通过合成miR-214的模拟物或抑制剂瞬时过表达或抑制表达检测miR-214对成牙骨质细胞的分化及调控；同时通过生物信息分析及报告基因检测Osx是否为miR-214的靶基因；此外检测在miR-214调控过程中wnt信号通路的表达情况；另一方面我们构建miR-214重组慢病毒过表达及抑制载体并注射我们已经构建好的Osx转基因小鼠（Osx Tg）和正常的野生型小鼠（WT），观察小鼠牙骨质的发育形成情况。本课题试图证明miR-214靶向作用Osterix调控成牙骨质细胞的分化，进一步为牙骨质的组织工程提供新的方向。

我们利用microRNA芯片研究发现在小鼠成牙骨质细胞矿化诱导中，miR-214、miR-3064-3p和miR-361-3p的表达显著变化。但miR-214调控靶基因Osx的表达不稳定，于是我们课题组主要着手研究miR-3064-3p和miR-361-3p。miR-3064-3p和miR-361-3p分别靶向作用Dkk1和Nfat5，通过相关信号通路影响成牙骨质细胞的分化。考虑到疾病状态下，成牙骨质细胞处于炎症环境中。因此，仅仅研究发育情况下miRNA对成牙骨质细胞的调控机制还是不够的，探索细胞在炎症条件下自我更新和增殖的分子机制至为重要。我们发现当TNF-α刺激的成牙骨质细胞时，miR-155-3p和miR-181b-5p的表达会发生明显变化。miR-155-3p和miR-181b-5p通过靶向Kctd1和Il-6，调控TNF-α抑制的成牙骨质细胞分化和诱导的炎症反应。同时，我们发现miR-338-3p基因敲除的小鼠能明显抵抗牙周炎的骨吸收，探索miR-338-3p在牙周炎发生发展中的重要作用，进一步为牙周组织工程提供新的方向。