Department of Biochemistry, College of Natural Sciences, Kangwon National University, Chuncheon, Gangwon‑Do 24341, Republic of Korea.
College of Pharmacy, Catholic University of Daegu, Hayang, Gyeongbuk 38430, Republic of Korea.
Int J Mol Med. 2018 Jul;42(1):569-578. doi: 10.3892/ijmm.2018.3627. Epub 2018 Apr 17.
Desoxyrhapontigenin (DRG), a stilbene compound from Rheum undulatum, has been found to exhibit various pharmacological activities, however, its impact on osteoclast formation has not been investigated. The present study investigated the effect of DRG on receptor activator of nuclear factor‑κB ligand (RANKL)‑induced osteoclast differentiation in mouse bone marrow macrophages (BMMs) and inflammation‑induced bone loss in vivo. BMMs or RAW264.7 cells were treated with DRG, followed by an evaluation of cell viability, RANKL‑induced osteoclast differentiation, actin‑ring formation and resorption pits activity. The effects of DRG on the RANKL‑induced phosphorylation of MAPK and the expression of nuclear factor of activated T cells cytoplasmic 1 (NFATc1) and c‑Fos were evaluated using western blot analysis once the BMMs were exposed to RANKL and DRG. The expression levels of osteoclast marker genes were also evaluated using western blot analysis and reverse transcription‑quantitative polymerase chain reaction A lipopolysaccharide (LPS)‑induced murine bone loss model was used to evaluate the protective effect of DRG on inflammation‑induced bone‑loss. The results demonstrated that DRG suppressed the RANKL‑induced differentiation of BMMs into osteoclasts, osteoclast actin‑ring formation and bone resorption activity in a dose‑dependent manner. Furthermore, DRG significantly inhibited LPS‑induced bone loss in a mouse model. At the molecular level, DRG inhibited the RANKL‑induced activation of extracellular signal‑regulated kinase, the expression of c‑Fos, and the induction of NFATc1, a crucial transcription factor for osteoclast formation. DRG decreased the expression levels of osteoclast marker genes, including matrix metalloproteinase‑9, tartrate‑resistant acid phosphatase and cathepsin K. In conclusion, these findings suggested that DRG inhibited the differentiation of BMMs into mature osteoclasts by suppressing the RANKL‑induced activator protein‑1 and NFATc1 signaling pathways, and may be a potential candidate for treating and/or preventing osteoclast‑associated diseases, including osteoporosis.
虎杖苷（DRG）是一种来自大黄的二苯乙烯类化合物，已被发现具有多种药理活性，但其对破骨细胞形成的影响尚未得到研究。本研究探讨了 DRG 对核因子-κB 受体激活剂配体（RANKL）诱导的小鼠骨髓巨噬细胞（BMM）破骨细胞分化和体内炎症诱导骨丢失的影响。用 DRG 处理 BMM 或 RAW264.7 细胞，然后评估细胞活力、RANKL 诱导的破骨细胞分化、肌动蛋白环形成和吸收陷窝活性。用 DRG 处理 BMM 后，通过 Western blot 分析评估 DRG 对 RANKL 诱导的丝裂原活化蛋白激酶磷酸化和活化 T 细胞核因子胞浆 1（NFATc1）和 c-Fos 表达的影响。还通过 Western blot 分析和逆转录-定量聚合酶链反应评估破骨细胞标记基因的表达水平。采用脂多糖（LPS）诱导的小鼠骨丢失模型评价 DRG 对炎症诱导骨丢失的保护作用。结果表明，DRG 以剂量依赖性方式抑制 RANKL 诱导的 BMM 向破骨细胞分化、破骨细胞肌动蛋白环形成和骨吸收活性。此外，DRG 显著抑制 LPS 诱导的小鼠模型中的骨丢失。在分子水平上，DRG 抑制了 RANKL 诱导的细胞外信号调节激酶的激活、c-Fos 的表达以及破骨细胞形成的关键转录因子 NFATc1 的诱导。DRG 降低了破骨细胞标记基因的表达水平，包括基质金属蛋白酶-9、抗酒石酸酸性磷酸酶和组织蛋白酶 K。总之，这些发现表明，DRG 通过抑制 RANKL 诱导的激活蛋白-1 和 NFATc1 信号通路抑制 BMM 向成熟破骨细胞的分化，可能是治疗和/或预防破骨细胞相关疾病（包括骨质疏松症）的潜在候选药物。
