Objectives: This work aimed to investigate the molecular mechanism of cyclic tensile stress (CTS) stimulating autophagy in human periodontal ligament cells (hPDLCs).
Methods: hPDLCs were isolated and cultured from normal periodontal tissues. hPDLCs were loaded with tensile stress by force four-point bending extender to simulate the autophagy of hPDLCs induced by orthodontic force du-ring orthodontic tooth movement. XMU-MP-1 was used to inhibit the Hippo signaling pathway to explore the role of the Hippo-YAP signaling pathway in activating hPDLC autophagy by tensile stress. The expression levels of autophagy-related genes (Beclin-1, LC3, and p62) in hPDLCs were detected by real-time quantitative polymerase chain reaction. Western blot was used to detect the expression levels of autophagy-related proteins (Beclin-1, LC3-Ⅱ/LC3-Ⅰ, and p62) and Hippo-YAP pathway proteins (active-YAP and p-YAP) in hPDLCs. Immunofluorescence was used to locate autophagy-related proteins (LC3-Ⅱand p62) and Hippo-YAP pathway proteins (active-YAP) of hPDLCs.
Results: CTS-activated autophagy in hPDLCs and expression of autophagy-related proteins initially increased and then decreased; it began to increase at 30 min, peaked at 3 h, and decreased (P<0.05). CTS increased the expression of active-YAP protein and decreased the expression of p-YAP protein (P<0.05). When XMU-MP-1 inhibited the Hippo-YAP signaling pathway (P<0.05), active-YAP protein was promoted to enter the nucleus and autophagy expression was enhanced (P<0.05).
Conclusions: The Hippo-YAP signaling pathway is involved in the regulation of autophagy activation in hPDLCs under CTS.
目的: 探究周期性张应力（CTS）作用下人牙周膜细胞（hPDLCs）自噬激活的分子机制。方法: 分离培养正常牙周组织的hPDLCs，利用Forcel四点弯曲细胞加力仪对hPDLCs加载张应力模拟正畸牙移动过程中正畸力诱导的张力侧hPDLCs自噬，利用XMU-MP-1抑制Hippo信号通路探究Hippo-YAP信号通路在张应力激活hPDLCs自噬中的作用。采用实时荧光定量聚合酶链反应（RT-qPCR）检测hPDLCs自噬相关基因（Beclin-1、LC3、p62）的表达；采用蛋白免疫印迹（Western blot）检测hPDLCs自噬相关蛋白（Beclin-1、LC3-Ⅱ/LC3-Ⅰ、p62）及Hippo-YAP通路相关蛋白（active-YAP、p-YAP）的表达；采用免疫荧光染色定位hPDLCs自噬相关蛋白（LC3-Ⅱ、p62）及Hippo-YAP通路相关蛋白（active-YAP）。结果: CTS激活hPDLCs的自噬，自噬相关因子表达随加力时间的延长呈先升高后降低的趋势，30 min自噬开始，3 h达到高峰，随后出现下调（P<0.05）；CTS促进active-YAP蛋白表达增加，p-YAP蛋白表达降低（P<0.05）。XMU-MP-1抑制Hippo-YAP信号通路后（P<0.05），促进active-YAP蛋白进入细胞核，自噬表达增强（P<0.05）。结论: Hippo-YAP信号通路参与CTS作用下hPDLCs自噬激活的调控。.
Keywords: Hippo-YAP signaling pathway; autophagy; human periodontal ligament cells; tensile stress.