School of Pharmaceutical Sciences, Southern Medical University, Guangzhou 510515, China; School of Pharmaceutical Sciences, Fujian Traditional Chinese Medicine University, Fuzhou 350122, China.
School of Pharmaceutical Sciences, Southern Medical University, Guangzhou 510515, China.
Eur J Pharmacol. 2016 May 15;779:66-79. doi: 10.1016/j.ejphar.2016.03.014. Epub 2016 Mar 7.
Sinomenine (SIN) is an anti-inflammatory and anti-arthritic alkaloid derived from Sinomenioum acutum. Effects of SIN on lipopolysaccharide (LPS)-induced osteolysis have not been reported. Here, we found that SIN reduced LPS-induced erosion of skull bones in C57BL/6 mice significantly. LPS can induce bone-absorbing osteoclast formation independent of RANKL in pre-osteoclastic RAW264.7 cells in vitro. Here, SIN suppressed LPS-induced osteoclast formation and osteoclast survival in RAW264.7 cells. Expression of osteoclastic-specific marker genes was also inhibited by SIN during osteoclast differentiation and osteoclast survival stimulated with LPS. SIN showed much stronger inhibitory effects on expression of Fra-1 and MMP-9 mRNA in osteoclast differentiation rather than osteoclast survival. SIN dramatically inhibited LPS-induced TNF-α production in vitro and in vivo. Further signaling studies revealed that SIN suppressed the activation and relative gene expression of three notable nuclear factors (NF-κB, AP-1, NFAT), reduced intracellular levels of Ca(2+), and down-regulated phosphorylation of MAPK p38 (but not JNK) in LPS-induced osteoclastogenesis. Focusing on upstream signals after LPS stimulation, SIN decreased expression of TLR4 and TRAF6 during osteoclast differentiation, and reduced expression of TLR4 (but not TRAF6) in osteoclast survival. These data suggest that SIN might be a potential agent for the treatment of osteolysis caused by Gram-negative bacteria infection or inflammation due to its inhibition of osteoclastogenesis through reduction of TLR4/TRAF6 expression and downstream signal transduction.
青藤碱（SIN）是一种从青风藤中提取的抗炎和抗关节炎生物碱。SIN 对脂多糖（LPS）诱导的溶骨性作用的影响尚未报道。在这里，我们发现 SIN 可显著减少 LPS 诱导的 C57BL/6 小鼠颅骨侵蚀。LPS 可在体外诱导破骨前体 RAW264.7 细胞中独立于 RANKL 诱导破骨细胞形成。在这里，SIN 抑制 LPS 诱导的 RAW264.7 细胞中的破骨细胞形成和破骨细胞存活。在破骨细胞分化和 LPS 刺激的破骨细胞存活过程中，SIN 还抑制破骨细胞特异性标记基因的表达。SIN 在破骨细胞分化过程中对 Fra-1 和 MMP-9 mRNA 的表达显示出更强的抑制作用，而不是对破骨细胞存活的抑制作用。SIN 可显著抑制 LPS 诱导的 TNF-α在体外和体内的产生。进一步的信号研究表明，SIN 抑制 LPS 诱导的破骨细胞发生过程中三个显著核因子（NF-κB、AP-1、NFAT）的激活和相对基因表达，降低细胞内 Ca(2+)水平，并下调 MAPK p38 的磷酸化（但不包括 JNK）。在 LPS 刺激后的上游信号中，SIN 在破骨细胞分化过程中降低 TLR4 和 TRAF6 的表达，并且在破骨细胞存活过程中降低 TLR4（但不降低 TRAF6）的表达。这些数据表明，SIN 可能是一种潜在的治疗革兰氏阴性菌感染或炎症引起的溶骨性疾病的药物，因为它通过降低 TLR4/TRAF6 表达和下游信号转导来抑制破骨细胞发生。
