Table2_Nrf2 Activation Is Involved in Cyclic Mechanical Stress-Stimulated Osteogenic Differentiation in Periodontal Ligament Stem Cells via PI3K/Akt Signaling and HO1-SOD2 Interaction.XLS

Nuclear factor erythroid-2-related factor-2 (Nrf2), the major transcriptional regulator in antioxidant response and cellular defense, had the vital effect on regulating osteogenic differentiation. Our previous study revealed that Nrf2 activation was involved in cyclic mechanical stress-stimulated osteogenic differentiation in the human periodontal ligament stem cells (PDLSCs). However, the mechanisms of Nrf2 underlying this process remained unclear. The goal of the study was to explore the mechanisms of Nrf2 in PDLSCs during cyclic mechanical stress-stimulated osteogenic differentiation via the tandem mass tag (TMT)-based liquid chromatography tandem-mass spectrometry (LC-MS/MS) analysis. And we applied tert-Butylhydroquinone (t-BHQ), the Nrf2 activator, to the orthodontic rats and detected the expression levels of the osteogenesis markers by immunohistochemistry (IHC) staining. Our results showed that Nrf2 activation in PDLSCs was involved in cyclic mechanical stress-stimulated osteogenic differentiation via phosphoinositide 3 kinase (PI3K)/protein kinase B (Akt) pathway. The protein-protein interaction between Akt and Nrf2 was detected. And the protein-protein interaction between heme oxygenase 1 (HO1) and superoxide dismutase 2 (SOD2), the downstream antioxidants of Nrf2, was associated with cyclic mechanical stress-stimulated osteogenic differentiation. T-BHQ enhanced the expression levels of the osteogenesis markers in orthodontic rats. Nrf2 might possess the potential to be a feasible molecular target in orthodontics.

核因子E2相关因子2（Nuclear factor erythroid-2-related factor 2, Nrf2）是抗氧化应答与细胞防御过程中的核心转录调控因子，对成骨分化调控具有关键作用。本团队前期研究发现，Nrf2激活参与了周期性机械应力刺激下人牙周膜干细胞（human periodontal ligament stem cells, PDLSCs）的成骨分化过程。然而，该过程中Nrf2发挥作用的具体分子机制尚未明确。本研究旨在通过基于串联质量标签（tandem mass tag, TMT）的液相色谱-串联质谱（liquid chromatography tandem-mass spectrometry, LC-MS/MS）分析，探究周期性机械应力刺激下PDLSCs中Nrf2调控成骨分化的分子机制。本研究将Nrf2激活剂叔丁基对苯二酚（tert-Butylhydroquinone, t-BHQ）应用于正畸大鼠模型，并通过免疫组织化学（immunohistochemistry, IHC）染色检测成骨标志物的表达水平。研究结果显示，PDLSCs中Nrf2的激活通过磷脂酰肌醇3激酶（phosphoinositide 3 kinase, PI3K）/蛋白激酶B（protein kinase B, Akt）通路参与周期性机械应力诱导的成骨分化。研究检测到Akt与Nrf2之间存在蛋白质相互作用。作为Nrf2下游抗氧化因子的血红素加氧酶1（heme oxygenase 1, HO1）与超氧化物歧化酶2（superoxide dismutase 2, SOD2）之间的蛋白质相互作用，也与周期性机械应力诱导的成骨分化密切相关。t-BHQ可上调正畸大鼠体内成骨标志物的表达水平。Nrf2有望成为正畸治疗中可行的分子靶点。