Anemoside B4 attenuates RANKL-induced osteoclastogenesis by upregulating Nrf2 and dampens ovariectomy-induced bone loss

AUTHORS

Zhen Cao, Xuben Niu, Maihuan Wang, Siwang Yu, Mingkun Wang, Silong Mu, Chuan Liu, Yaxi Wang

ABSTRACT

Increased numbers and functional overactivity of osteoclasts are the pathological basis for bone loss diseases such as osteoporosis, which are characterized by cortical bone thinning, decreased trabecular bone quantity, and reduced bone mineral density. Effective inhibition of osteoclast formation and bone resorption are important means of treating such skeletal diseases. Anemoside B4 (AB4), the main active component of Pulsatilla chinensis, possesses a wide range of anti-inflammatory and immunoregulatory effects. However, its effect and mechanism in osteoclast differentiation remain unclear. In this study, we found through tartrate-resistant acidic phosphatase (TRAcP) staining and immunofluorescence staining that AB4 inhibited the differentiation, fusion, and bone-resorption functions of osteoclasts induced by receptor activator of nuclear factor κB ligand (RANKL) in vitro. Additionally, real time PCR (RT-qPCR) and western blot analysis showed AB4 downregulated the expression of osteoclast marker genes, including Nfatc1, Fos, and Ctsk, while upregulating Nrf2 expression. AB4 (5 mg/kg) alleviated bone loss in ovariectomized mice by inhibiting osteoclast formation. Furthermore, the knockout of Nrf2 weakened the inhibitory effects of AB4 on osteoclast formation and related gene expression. In summary, the results suggest AB4 can inhibit osteoclast differentiation and function by activating Nrf2 and indicate AB4 may be a candidate drug for osteoporosis.

The synergistic treatment of cyclolinopeptide J and calcium carbonate nanoparticles for osteoporosis via BMP/Wnt signaling: In vivo and in vitro

AUTHORS

Jiazi Chen, Wen Li, Yee-Ying Lee, Zizhe Cai, Jing Chen, Yong Wang

ABSTRACT

This research focuses on the investigation of cyclolinopeptide J (CLJ), a bioactive peptide naturally present in flaxseed, which loaded in porous calcium carbonate (CA) nanoparticles (JCA) to augment the effectiveness of CLJ on osteogenesis. The JCA was successfully synthesized with a high loading capacity (47.8 %) and encapsulation efficiency (95.6 %). Results showed that CLJ exerted an excellent osteogenic effect at 10 µM in MC3T3-E1 cells. CLJ and CA have been shown to activate osteogenic factors by modulating the Wnt/β-catenin and BMP/Smad signaling pathways. Furthermore, JCA treatment exhibited a remarkable ability to restore the intricate trabecular characteristics of bone in OVX-induced mice. The trabecular bone architecture observed in JCA-treated mice closely resembled that of healthy controls, indicating a substantial amelioration of osteoporotic bone loss. Our findings highlight the synergistic treatment of CLJ and CA in restoring bone integrity and structure and provide compelling evidence for the effectiveness of this novel functional supplement.

Inhibition of KIF11 ameliorates osteoclastogenesis via regulating mTORC1-mediated NF-κB signaling

AUTHORS

Jiansen Miao, Hanbing Yao, Jian Liu, Zhixian Huang, Chengge Shi, Xinyu Lu, Junchen Jiang, Rufeng Ren, Chenyu Wang, Youjin Pan, Te Wang, Haiming Jin

ABSTRACT

Osteoporosis, characterized by over-production and activation of osteoclasts, has become a major health problem especially in elderly women. In our study, we first tested the effect of Caudatin (Cau) in osteoclastogenesis, which is separated from Cynanchum auriculatum as a species of C-21 steroidal glyosides. The results indicated that Cau suppressed osteoclastogenesis in a time- and dose-dependent manner in vitro. Mechanistically, Cau was identified to inhibit NF-κB signaling pathway via modulation of KIF11-mediated mTORC1 activity. In vivo, by establishing an ovariectomized (OVX) mouse model to mimic osteoporosis, we confirmed that Cau treatment prevented OVX-induced bone loss in mice. In conclusion, we demonstrated that Cau inhibited NF-κB signaling pathway via modulation of KIF11-mediated mTORC1 activity to suppress osteoclast differentiation in vitro as well as OVX-induced bone loss in vivo. This provides the possibility of a novel prospective drug for osteoporosis remedies.

Ano5 modulates calcium signaling during bone homeostasis in gnathodiaphyseal dysplasia

AUTHORS

Xin Li, Lei Wang, Hongwei Wang, An Qin & Xingjun Qin

ABSTRACT

ANO5 encodes transmembrane protein 16E (TMEM16E), an intracellular calcium-activated chloride channel in the endoplasmic reticulum. Mutations in ANO5 are associated with gnathodiaphyseal dysplasia (GDD), a skeletal disorder causing the jaw deformity and long bone fractures. However, the coordinated mechanism by which ANO5 mediates bone homeostasis in GDD remains poorly defined. Here, we show that ablation of Ano5 reduced intracellular calcium transients, leading to defects in osteogenesis and osteoclastogenesis and thus bone dysplasia. We found a causative de novo ANO5 frameshift insertion mutation (p.L370_A371insDYWRLNSTCL) in a GDD family with osteopenia, accompanied by a decrease in TMEM16E expression and impaired RANKL-induced intracellular calcium ([Ca2+]i) oscillations in osteoclasts. Moreover, using Ano5 knockout (KO) mice, we found that they exhibited low bone volume, abnormal calcium deposits, and defective osteoblast and osteoclast differentiation. We also showed that Ano5 deletion in mice significantly diminished [Ca2+]i oscillations in both osteoblasts and osteoclasts, which resulted in reduced WNT/β-Catenin and RANKL-NFATc1 signaling, respectively. Osteoanabolic treatment of parathyroid hormone was effective in enhancing bone strength in Ano5 KO mice. Consequently, these data demonstrate that Ano5 positively modulates bone homeostasis via calcium signaling in GDD.