YAP活化介导钛腐蚀产物促进种植体周围炎的作用机制

With the promotion of dental implant technology in our country in recent years, the number of patients suffering from peri-implantitis has been increasing every year. But the pathogenesis of this disease has not been clarified yet. Due to its unique osseointegration property, titanium is the ideal material for dental implants. However, previous studies and our preliminary studies showed that titanium corrosion behavior, induced by surface oxide film damage, is one of the triggering factors of peri-implantitis. Our further studies found that inflammatory microenvironment could enhance the corrosion of titanium, while titanium ions, the corrosion product, could activate the Yes-associated protein (YAP). As the key transcriptional co-activator, YAP activation can interfere with osteoblast behavior on the one hand, and promote osteoclast differentiation and inflammation reaction on the other hand, resulting in osteoblast-osteoclasts imbalance and accelerated destruction of implant osseointegration. Therefore, we hypothesize that titanium corrosion product can activate YAP to regulate osteoblast-osteoclast coupling and pro-inflammatory processes, thereby promoting the progress of peri-implantitis. In this project, on the basis of our preliminary work, the effects of inflammatory microenvironment on the titanium corrosion behavior and its corrosion product will be studied. Then, through cellular molecular biology and animal experiments, the mechanism of titanium corrosion product promoting peri-implantitis mediated by YAP activation will be elucidated. This project aims to deepen the understanding of the pathogenesis of peri-implantitis and provide foundations for exploring early interventions.

随着近年来种植技术在我国的推广，种植体周围炎患病人数亦逐年增加，但其发病机制尚未明确。由于独特的骨结合性能，钛是口腔种植体的理想材料。然而，既往研究与本课题组前期研究表明，表面氧化膜受损引发的钛腐蚀行为，是种植体周围炎的触发因素之一。我们进一步研究发现，炎症微环境会增强钛的腐蚀，而腐蚀产物钛离子能激活Yes相关蛋白(YAP)。作为关键的转录共激活因子，YAP活化一方面可干扰成骨细胞行为，另一方面可促进破骨细胞分化和炎症反应，导致成骨-破骨失衡和种植体骨结合的加速破坏。因此，我们推测：钛腐蚀产物能通过活化YAP调控成骨-破骨耦联和促炎过程，推动种植体周围炎的进展。基于前期工作基础，本项目拟研究炎症微环境对钛腐蚀行为及其腐蚀产物的影响，再通过细胞分子生物学和动物实验，揭示YAP活化介导钛腐蚀产物促进种植体周围炎的作用机制。本项目有望加深对种植体周围炎发病机制的认识，为探寻早期遏制措施提供依据。

随着近年来种植技术在我国的推广，种植体周围炎患病人数亦逐年增加，但其发病机制目前仍未明确。既往研究与本课题组的前期研究表明，钛腐蚀行为是种植体周围炎的触发因素之一，而作为钛腐蚀产物，钛离子能活化关键的转录共激活因子Yes相关蛋白（YAP），但其促进种植体周围炎的分子机制亟待明确。本项目通过扫描电镜、X射线光电子能谱（XPS）、钛腐蚀动力学检测、钛离子释放检测、巨噬细胞钛离子暴露模型、慢病毒转染、Hippo-YAP和NF-κB通路关键分子表达、种植动物模型、Micro-CT、硬组织切片、免疫组化、免疫荧光等体内外实验方法，系统研究了YAP 活化介导钛腐蚀产物促进种植体周围炎的作用机制。研究结果如下：(1) 通过模拟炎症微环境，明确了炎症条件下定植于钛表面的破骨细胞通过破坏钛表面微结构和元素组成加速生物腐蚀和钛离子释放的腐蚀动力学机理。(2) 揭示了钛离子调控巨噬细胞行为的分子机制：钛离子可活化巨噬细胞胞浆中的YAP，增强其核转位，激活下游靶分子，参与NF-κB通路的激活，诱发促炎反应，而NF-κB激活后也会通过信号交互影响Hippo-YAP通路关键分子YAP的表达。(3) 阐明了钛离子暴露对种植体周围骨代谢和骨结合的影响：构建新西兰兔上颌前牙即刻种植动物模型，再基于该模型构建钛离子暴露种植动物模型，通过Micro-CT影像学以及组织学分析发现，钛离子暴露会激发种植体周围软硬组织的炎症反应，降低种植体周围骨体积、骨密度和种植体-骨接触率，干扰种植体骨结合，导致成骨-破骨耦联失衡，进而促进种植体周围炎的发生发展。本项目证实了炎症微环境中破骨细胞介导的钛生物腐蚀，探索了该现象的腐蚀动力学机理，明确了钛离子对巨噬细胞行为的调控作用及其对种植体周围骨代谢的不良影响，并进一步揭示了Hippo-YAP/NF-κB信号通路交联在钛离子调控巨噬细胞行为中的分子机制。该研究结果有望加深对种植体周围炎发病机制的认识，并为早期遏制措施的探寻提供理论和实验依据。