Xiao Hui-Hui, Gao Quan-Gui, Zhang Yan, Wong Ka-Chung, Dai Yi, Yao Xin-Sheng, Wong Man-Sau
State Key Laboratory of Chinese Medicine and Molecular Pharmacology (Incubation), Shenzhen Research Institute of The Hong Kong Polytechnic University, Shenzhen 518057, PR China; Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, PR China.
Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, PR China.
J Steroid Biochem Mol Biol. 2014 Oct;144 Pt B:382-91. doi: 10.1016/j.jsbmb.2014.08.002. Epub 2014 Aug 5.
Sambucus williamsii Hance (SWH) has been used for treatment of bone and joint disease in China for thousands of years. Our previous study showed that SWH extract and its bioactive fraction could effectively prevent oestrogen-deficiency induced bone loss in ovariectomized mice. The present study aimed to study the bone protective effects of vanillic acid (VA), a phenolic acid isolated from the bioactive fraction of SWH, and to characterize the signaling pathways that mediated its actions in rat osteoblast-like UMR 106 cells. VA significantly stimulated proliferation, alkaline phosphatase (ALP) activities as well as significantly altered the mRNA expression of genes involved in osteoblast functions and osteoclastogenesis in UMR 106 cells. Co-treatment of UMR 106 cells with 10(-6)M ICI182,780 (a specific oestrogen receptor (ER) antagonist) abolished the stimulatory effects of VA on osteoblast proliferation and ALP activities, suggesting the role of ER in mediating its actions. However, VA (10(-12) to 10(-6)M) failed to bind to ERα or ERβ and did not activate oestrogen response element (ERE)-luciferase activities via ERα or ERβ in UMR 106 cells. In contrast, 10(-10) and 10(-8)M of VA induced the phosphorylation of MEK 1/2, ERK1/2 and ERα at Ser118 residue in UMR 106 cells, suggesting that MAP kinase-mediated pathway is involved in mediating its actions. Taken together, our results indicated that VA is a bioactive compound in SWH that exerts stimulatory effects in osteoblast-like cells via non-genomic, but not classical, ER signaling pathway.
在中国，接骨木已被用于治疗骨与关节疾病达数千年之久。我们之前的研究表明，接骨木提取物及其生物活性组分能够有效预防去卵巢小鼠因雌激素缺乏所致的骨质流失。本研究旨在探讨香草酸（VA）的骨骼保护作用，VA是从接骨木生物活性组分中分离得到的一种酚酸，并对其在大鼠成骨样UMR 106细胞中介导作用的信号通路进行表征。VA显著刺激了UMR 106细胞的增殖、碱性磷酸酶（ALP）活性，同时显著改变了参与成骨细胞功能和破骨细胞生成的基因的mRNA表达。用10(-6)M ICI182,780（一种特异性雌激素受体（ER）拮抗剂）与UMR 106细胞共同处理，消除了VA对成骨细胞增殖和ALP活性的刺激作用，提示ER在介导其作用中发挥作用。然而，VA（10(-12)至10(-6)M）未能与ERα或ERβ结合，且在UMR 106细胞中未通过ERα或ERβ激活雌激素反应元件（ERE）-荧光素酶活性。相反，10(-10)和10(-8)M的VA诱导了UMR 106细胞中MEK 1/2、ERK1/2和Ser118残基处的ERα的磷酸化，提示丝裂原活化蛋白激酶介导的信号通路参与介导其作用。综上所述，我们的结果表明，VA是接骨木中的一种生物活性化合物，其通过非基因组而非经典的ER信号通路在成骨样细胞中发挥刺激作用。
