Glycyrrhizin Suppresses RANKL-Induced Osteoclastogenesis and Oxidative Stress Through Inhibiting NF-κB and MAPK and Activating AMPK/Nrf2
Glycyrrhizin Suppresses RANKL-Induced Osteoclastogenesis and Oxidative Stress Through Inhibiting NF-κB and MAPK and Activating AMPK/Nrf2
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DOI：
10.1007/s00223-018-0425-1
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发表时间：
2018-09-01
影响因子：
4.2
通讯作者：
Xu, Wei
中科院分区：
文献类型：
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作者：
Li, Zhikun;Chen, Chao;Xu, Wei
骨质疏松症的治疗包括抑制骨吸收和破骨细胞生成。甘草酸(GLY)是一种三萜皂苷，被认为是甘草中最有效的药用成分。它具有很强的抗炎、抗氧化和抗肿瘤特性。我们研究了GLY对破骨细胞生成、骨吸收和细胞内氧化应激的影响及其分子机制。体外破骨细胞生成实验采用加入和不加入甘草酸的骨髓单核细胞。我们还用ELISA法检测了甘草甜素对内毒素刺激的RAW 264.7细胞分泌肿瘤坏死因子-α、白介素1-β和白介素6的影响。RT-PCR法检测甘草酸苷对破骨细胞相关基因NFATc1、c-fos、Trap和组织蛋白酶K(CK)表达的影响。核因子kappa-I配体受体激活剂(RANKL)刺激破骨细胞在甘草甜素存在和不存在的情况下检测细胞内的活性氧(ROS)。在甘草酸苷抑制破骨细胞分化的过程中，用蛋白印迹法检测AMPK、Nrf2、NF-kappaB和MAPK的磷酸化。结果显示，甘草甜素显著抑制RANKL诱导的破骨细胞分化，下调NFATc1、c-fos、TRAP、CK、DC-STAMP和OSCAR的表达，抑制p65、p38和JNK的表达。甘草甜素可显著减少炎性细胞因子(TNF-α、IL-1β和IL-6)的分泌。此外，甘草酸通过诱导AMPK磷酸化和NRF2的核转移减少破骨细胞中ROS的形成，导致抗氧化酶HO-1、NQO-1和GCLC上调。综上所述，我们发现甘草酸抑制RANKL诱导的破骨细胞生成。甘草甜素可通过抑制MAPK和NF-kappa B通路，激活AMPK/NRF2信号通路，减轻氧化应激。因此，甘草甜素有可能成为治疗骨质疏松和骨吸收的有效药物。
The treatment for osteoporosis involves inhibiting bone resorption and osteoclastogenesis. Glycyrrhizin (GLY) is a triterpenoid saponin glycoside known to be as the most medically efficacious component of the licorice plant. It has strong anti-inflammatory, antioxidant, and antitumor properties. We investigated the effect of GLY on osteoclastogenesis, bone resorption, and intracellular oxidative stress and its molecular mechanisms. In vitro osteoclastogenesis assays were performed using bone marrow monocytes with and without glycyrrhizin. We also evaluated the effects of glycyrrhizin on the secretion of TNF-alpha, IL-1 beta, and IL-6 in LPS-stimulated RAW 264.7 cells using ELISA. The effects of glycyrrhizin on the expression of osteoclast-related genes, such as Nfatc1, c-fos, Trap, and cathepsin K (CK), were investigated by RT-PCR. Intracellular reactive oxygen species (ROS) were detected in receptor activator of nuclear factor kappa-I' ligand (RANKL)-stimulated osteoclasts in the presence and absence of glycyrrhizin. During the inhibition of osteoclastogenesis by glycyrrhizin, phosphorylation of AMPK, Nrf2, NF-kappa B, and MAPK was analyzed using western blotting. Our results showed that glycyrrhizin significantly inhibited RANKL-induced osteoclastogenesis, downregulated the expression of NFATc1, c-fos, TRAP, CK, DC-STAMP, and OSCAR, and inhibited p65, p38, and JNK. Glycyrrhizin was found to significantly decrease the secretion of inflammatory cytokines (TNF-alpha, IL-1 beta, and IL-6). Additionally, glycyrrhizin reduced the formation of ROS in osteoclasts by inducing AMPK phosphorylation and nuclear transfer of NRF2, resulting in an upregulation of antioxidant enzymes, such as HO-1, NQO-1, and GCLC. In summary, we found that glycyrrhizin inhibited RANKL-induced osteoclastogenesis. It was also indicated that glycyrrhizin could reduce oxidative stress by inhibiting the MAPK and NF-kappa B pathways and activating the AMPK/NRF2 signaling. Therefore, glycyrrhizin may be used as an effective therapeutic agent against osteoporosis and bone resorption.