熊果酸以IKKβ cys-179为靶点调控人工关节磨损颗粒诱导无菌性松动的效果与机制研究

Periprosthetic aseptic loosening resulting from wear particle-induced aseptic inflammation, and excessive formation and activation of osteoclasts is the main complication affecting the long-dated stability and in-service life of artificial joints. Previous studies have confirmed blocking NF-κB signaling pathway can effectively inhibit inflammation, and osteoclast differentiation and maturation, and then ameliorate wear particle-induced osteolysis,in which the activation loop in IκB kinase β(IKKβ）plays a pivotal role. Thus, cysteine 179 (cys-179) located in the centre of the loop may be another potential target. Recent research shows that ursolic acid (UA) can produce anti-inflammatory and other immunomodulatory effects through inhibiting IKKβ, Moreover, our research group has proven that the effects of UA on osteoclasts were related to the inhibiton of IKKβ. However, the research of UA on the field of the signaling pathway in osteoclastogenesis (NF-κB-related RANKL/RANK signaling pathway) has not yet been involved and the specific mechanism remains unclear. Therefore, by using various technologies (gene site-directed mutagenesis, gene targeting technology etc.), this study aims to explore the possible mechanism that UA acts on the cysteine-179 of IKKβ to regulate the signaling pathway in the osteoclast differentiation and maturation, and aims to observe the effects of UA on inhibiting artificial joint wear particle-induced osteolysis. This study will provide a new idea for preventing and treating long-dated aseptic loosening of artificial joint from the point of view of traditional Chinese medicine and pharmacology.

磨损颗粒诱导的无菌性炎症及破骨细胞过度形成和活化导致的假体无菌性松动是影响人工关节远期稳定和使用寿命的主要并发症。研究证明，阻断NF-κB信号通路可有效抑制炎症的产生并阻碍破骨细胞的分化、成熟，从而抑制磨损颗粒诱导的骨溶解，IKKβ中的活化环在该过程中起重要作用，因此，位于该活化环中心的半胱氨酸残基cys-179可能是另一潜在靶点。近来研究表明，中药单体成分熊果酸可通过抑制IKKβ产生抗炎等免疫调节作用，本课题组前期研究证实其对破骨细胞的作用与IKKβ的抑制有关。然而，其在破骨细胞分化成熟信号通路（NF-κB相关的RANKL/RANK信号通路）中的研究尚未展开。因此，本研究通过基因定点突变及基因打靶等技术，探讨熊果酸以IKK-β中Cys-179为潜在靶点调控破骨细胞分化成熟信号通路的可能机制，并观察其抑制磨损颗粒诱导骨溶解的效果，为人工关节远期无菌性松动的防治从中医药角度提供新的突破口。

已成功证明IKKβ cys-179在人工关节磨损颗粒诱导骨溶解病理过程中的作用与机制以及与熊果酸的作用机制的关系。熊果酸能以IKKβ中cys-179为靶点调控破骨细胞分化成熟信号通路以达到抑制人工关节磨损颗粒诱导骨溶解的效果。本课题拟使用的基因定点突变技术和基因打靶技术来探索研究中草药活性成分在人工关节无菌性松动防治中的效果和潜在靶点，瞄准具有潜在应用价值的中草药成分熊果酸进行研究，为祖国医学应用于防治人工关节无菌性松动提供新的思路和突破口。