Liu Guangwang, Ma Chao, Wang Peian, Zhang Peiying, Qu Xinhua, Liu Shen, Zhai Zanjing, Yu Degang, Gao Juan, Liang Jun, Dai Weixiang, Zhou Lindong, Xia Mengjiao, Yang Huilin
Department of Orthopaedics, The First Affiliated Hospital of Soochow University, Suzhou, Jiangsu, China; Department of Orthopaedics, Xuzhou Central Hospital, Xuzhou Clinical School of Xuzhou Medical University, The Affiliated XuZhou Hospital of Medical College of Southeast University, Xuzhou Clinical Medical College of Nanjing University of Chinese Medicine, Xuzhou, Jiangsu, China.
Department of Orthopaedics, Xuzhou Central Hospital, Xuzhou Clinical School of Xuzhou Medical University, The Affiliated XuZhou Hospital of Medical College of Southeast University, Xuzhou Clinical Medical College of Nanjing University of Chinese Medicine, Xuzhou, Jiangsu, China.
Biochem Biophys Res Commun. 2017 Sep 16;491(2):388-395. doi: 10.1016/j.bbrc.2017.07.091. Epub 2017 Jul 18.
Bones are inflexible yet ever-changing metabolic organs, and bone homeostasis is maintained through two delicately regulated processes: bone construction and bone reabsorption. An imbalance in bone metabolism is linked to most orthopedic diseases, including osteoporosis and rheumatoid arthritis. Importantly, tumor necrosis factor-α (TNF-α) blocks osteoblast differentiation and stimulates osteoclast formation, resulting in delayed deposition of new bone and accelerated bone resorption, especially in rheumatoid arthritis patients with inflammatory conditions. Pilose antler peptide (PAP) isolated and purified from deer antlers has been shown to have beneficial effects on chronic inflammation. In the present study, we studied the impact of PAP on osteoblast differentiation and evaluated the regulatory mechanism, with particular emphasis on the effect of PAP on TNF-α-mediated NF-κB signaling. Mouse primary osteoblast cells were activated with bone morphogenetic protein-2 (BMP-2) for osteoblast differentiation. A significant stimulatory effect of PAP in osteoblastogenesis was observed using ALP activity and Alizarin Red S staining assays. Meanwhile, PAP significantly rescued TNF-α-induced impairment of osteoblast formation as well as mineralization. Furthermore, we found a similar trend upon analyzing osteoblast-specific gene expression. PAP significantly rescued TNF-α-mediated decrease in expression of osteoblast-specific genes. A molecular mechanism assay indicated that PAP significantly inhibited TNF-α-mediated stimulation of NF-κB signaling activity, as well as nuclear translocation of its subunit p65. Moreover, over-expression of p65 reversed the stimulatory effects of PAP on osteoblast differentiation. Furthermore, we also identified that PAP dose dependently inhibit osteoclastogenesis, and this effect might be achieved via suppressing NF-κB activity. In summary, this study shows that PAP promotes osteoblast differentiation and blocks TNF-α-mediated suppression of osteoblastogenesis in vitro via the NF-κB/p65 pathway, as well as inhibits osteoclastsogenesis in vitro. Therefore, PAP, a novel drug with both antiresorptive and osteoanabolic activity, shows therapeutic potential as an alternative treatment for osteolytic diseases, including rheumatoid arthritis and osteoporosis.
骨骼是坚硬却又不断变化的代谢器官，骨稳态通过两个精细调节的过程得以维持：骨构建和骨重吸收。骨代谢失衡与大多数骨科疾病相关，包括骨质疏松症和类风湿关节炎。重要的是，肿瘤坏死因子-α（TNF-α）会阻碍成骨细胞分化并刺激破骨细胞形成，导致新骨沉积延迟和骨吸收加速，尤其是在患有炎症的类风湿关节炎患者中。从鹿茸中分离纯化得到的鹿茸多肽（PAP）已被证明对慢性炎症具有有益作用。在本研究中，我们研究了PAP对成骨细胞分化的影响并评估了其调节机制，特别关注PAP对TNF-α介导的NF-κB信号传导的影响。用骨形态发生蛋白-2（BMP-2）激活小鼠原代成骨细胞以诱导成骨细胞分化。通过碱性磷酸酶（ALP）活性和茜素红S染色试验观察到PAP对成骨具有显著的刺激作用。同时，PAP显著挽救了TNF-α诱导的成骨细胞形成和矿化损伤。此外，在分析成骨细胞特异性基因表达时我们发现了类似的趋势。PAP显著挽救了TNF-α介导的成骨细胞特异性基因表达的降低。分子机制试验表明，PAP显著抑制TNF-α介导的NF-κB信号传导活性刺激及其亚基p65的核转位。此外，p65的过表达逆转了PAP对成骨细胞分化的刺激作用。此外，我们还发现PAP剂量依赖性地抑制破骨细胞生成，并且这种作用可能是通过抑制NF-κB活性来实现的。总之，本研究表明，PAP在体外通过NF-κB/p65途径促进成骨细胞分化并阻断TNF-α介导的对成骨细胞生成的抑制作用，同时在体外抑制破骨细胞生成。因此，PAP作为一种具有抗吸收和骨合成代谢活性的新型药物，显示出作为包括类风湿关节炎和骨质疏松症在内的溶骨性疾病替代治疗方法的治疗潜力。
