Liu Titi, Li Jin, Duan Meiyan, Wang Ya, Jiang Zhe, Gan Chunxia, Xiang Zemin, Sheng Jun, Wang Xuanjun, Xu Huanhuan
College of Science, Yunnan Agricultural University, Kunming, China.
Key Laboratory of Pu-Er Tea Science, Ministry of Education, Yunnan Agricultural University, Kunming, China.
J Cell Mol Med. 2024 Dec;28(23):e70256. doi: 10.1111/jcmm.70256.
The interaction between the receptor activator of nuclear factor-κB ligand (RANKL) and its receptor RANK is known to regulate osteoclastogenesis in bone remodelling and has become an important therapeutic target for the treatment of osteoporosis. Stephanine (SA), an isoquinoline aporphine-type alkaloid isolated from Stephania plants, possesses excellent anti-inflammatory effects and can be used for rheumatoid arthritis treatment. However, its specific role in osteoclastogenesis and osteoporosis remains unknown. In this study, we investigated the influence of SA on osteoclastogenesis in RANKL-stimulated RAW 264.7 cells and osteoporosis in an ovariectomised (OVX) mouse model and elucidated the underlying molecular mechanism. In vitro, SA can bind to RANK and RANKL with the K values of 3.7 and 76.47 μM, respectively, and disrupt the RANKL-RANK interaction, which inhibits RANKL-stimulated RANK-tumour necrosis factor receptor associated factor 6 (TRAF6) binding and RANK signalling pathways activation, downregulates the expression of key osteoclastogenesis-related regulatory factors in osteoclast precursors, ultimately suppresses osteoclast differentiation and activation. In vivo, SA significantly ameliorated bone loss through inhibiting osteoclastogenesis in OVX mice because of the decreased number of osteoclasts and the increased trabecular bone area. SA markedly inhibited the serum levels of tartrate-resistant acid phosphatase 5b (TRACP-5b), c-telopeptide of type I collagen (CTX-I), and RANKL, whereas it increased that of osteoprotegerin (OPG) in OVX mice. Additionally, SA strikingly downregulated the OVX-induced expression of osteoclast-specific genes and proteins. Taken together, this study elucidated that SA can effectively protect against osteoporosis by suppressing osteoclastogenesis via inhibition of the RANKL-RANK interaction, which supports the potential application of SA as a natural therapeutic agent for osteoporosis.
已知核因子κB受体活化因子配体（RANKL）与其受体RANK之间的相互作用在骨重塑过程中调节破骨细胞生成，并且已成为治疗骨质疏松症的重要治疗靶点。千金藤宁（SA）是从千金藤属植物中分离出的一种异喹啉阿朴啡型生物碱，具有出色的抗炎作用，可用于治疗类风湿性关节炎。然而，其在破骨细胞生成和骨质疏松症中的具体作用仍不清楚。在本研究中，我们研究了SA对RANKL刺激的RAW 264.7细胞中破骨细胞生成的影响以及对去卵巢（OVX）小鼠模型中骨质疏松症的影响，并阐明了潜在的分子机制。在体外，SA可以分别以3.7和76.47μM的K值与RANK和RANKL结合，并破坏RANKL-RANK相互作用，从而抑制RANKL刺激的RANK-肿瘤坏死因子受体相关因子6（TRAF6）结合和RANK信号通路激活，下调破骨细胞前体中关键的破骨细胞生成相关调节因子的表达，最终抑制破骨细胞的分化和激活。在体内，由于破骨细胞数量减少和小梁骨面积增加，SA通过抑制OVX小鼠中的破骨细胞生成而显著改善骨丢失。SA显著抑制OVX小鼠中抗酒石酸酸性磷酸酶5b（TRACP-5b）、I型胶原c端肽（CTX-I）和RANKL的血清水平，而提高骨保护素（OPG）的血清水平。此外，SA显著下调OVX诱导的破骨细胞特异性基因和蛋白质的表达。综上所述，本研究阐明SA可通过抑制RANKL-RANK相互作用来抑制破骨细胞生成，从而有效预防骨质疏松症，这支持了SA作为骨质疏松症天然治疗剂的潜在应用。
