高糖微环境下TLR4/NF-κΒ/miR-31信号轴调控牙周膜干细胞成骨分化的机制研究

Diabetes mellitus (DM) is a chronic metabolic disease that gives rise to impaired bone remodeling. It is well known that the osteogenic differentiation capacity of periodontal ligament stem cells (PDLSCs) was attenuated in high-glucose microenvironment, while the mechanism still remains unclear. Our previous study confirmed that the high expression of miR-31 is associated with the impaired osteogenic differentiation ability of PDLSCs in high glucose enviroment. Some evidence indicates that the TLR4 levels are elevated in diabetes and its complications. Furthermore, several studies found that NF-κΒ could bound to the promoter region of microRNA to up-regulate or inhibit the expression of microRNA. Our preliminary study observed a high expression of TLR4 under the environment of high-glucose existence and we also confirmed that there was a bounding site for NF-κΒ in the miR-31 promotor region. Thus current proposal will continue with and focus on exploring the effect of miR-31 on the osteogenic differentiation capacity of PDLSCs. Moreover, the role of TLR4/NF-κΒ/miR-31 plays in the osteogenic differentiation of PDLSCs under the high glucose microenvironment will be explored. This study will help lay the ground of understanding the mechanism of periodontal ligament stem cell differentiation under high-glucose microenvironment and provide fundamental support to the treatment of periodontis in diabetic patients.

糖尿病牙周炎患者发生进行性牙槽骨吸收的风险显著增高，牙周膜干细胞在高血糖状态下成骨分化能力减弱是其原因之一，但机制不明。我们前期研究显示高糖可通过上调牙周膜干细胞miR-31表达抑制其成骨分化。研究表明高血糖引起的TLR4活化可导致糖尿病并发症，而TLR4下游转录因子NF-κB通过调控多种miRNA表达参与疾病进程。预实验结果显示高糖可上调牙周膜干细胞TLR4表达，同时miR-31启动子区域存在NF-κB结合位点。因此我们推测高血糖诱导的TLR4表达升高可激活下游NF-κB活性，而活化的NF-κB与miR-31启动子结合促进其表达，miR-31的高表达又能抑制靶基因Satb2的表达从而减弱牙周膜干细胞成骨分化能力。本项目以miR-31为切入点，从体内外两方面探讨TLR4/NF-κΒ/miR-31调控牙周膜干细胞成骨分化的机制，为糖尿病牙周炎牙周骨缺损修复治疗提供一定的理论和实验依据。

糖尿病牙周炎患者发生进行性牙槽骨吸收的风险显著增高，高糖微环境下牙周膜干细胞成骨分化能力减弱被认为是其重要原因。本课题首先通过microRNA芯片筛选出高糖培养条件下牙周膜干细胞中显著上调的miR-31分子，进一步通过获得/缺失实验验证miR-31调控牙周膜干细胞成骨分化，机制为抑制靶基因Satb2表达。上游调控机制研究发现高糖微环境激活牙周膜干细胞NF-κB通路进而促进miR-31表达，抑制NF-κB通路活化可下调miR-31表达进而促进高糖环境下牙周膜干细胞成骨分化。最后建立糖尿病牙周炎大鼠模型，antagomir-31局部注射观察对模型大鼠牙槽骨吸收的影响，结果显示antagomir-31治疗可以显著减轻糖尿病牙周炎大鼠的牙槽骨吸收。研究结果为糖尿病牙周炎牙周骨缺损修复治疗提供一定的理论和实验依据。