Convergence Research Center for Smart Healthcare, Kyungsung University, Busan 48434, Republic of Korea.
Division of Food and Nutrition, Chonnam National University, Gwangju 61186, Republic of Korea.
Int J Biol Macromol. 2021 Jul 31;183:1410-1418. doi: 10.1016/j.ijbiomac.2021.05.122. Epub 2021 May 20.
Chitosan, a naturally occurring biodegradable and biocompatible polymer, has found use as a food additive, nutraceuticals, and functional foods in recent years. In this study, gallic acid-g-chitosan (GAC) was prepared by the insertion of GA onto plain chitosan (PC) via free radical-mediated grafting and its osteogenic effects were investigated in murine bone marrow-derived mesenchymal stem cells (mBMMSCs). Structural characterization of PC and GAC was performed using H NMR and FT-IR spectroscopy. The amount of GA successfully grafted onto PC was 111 mg GA/g GAC via the Folin-Ciocalteu's method. While PC and GAC promoted the increase in alkaline phosphatase activity and mineralization, GAC increased these factors significantly more than PC, indicating that the grafting of GA onto chitosan increased its osteogenic potential. Mechanistic study revealed that GAC activated Wnt1 and Wnt3a mRNA and protein expression as well as increased the translocation of β-catenin into the nucleus and upregulated the expression of β-catenin targeted genes including Runx2, osterix, type I collagen and cyclin D1. In addition, DKK-1, a Wnt antagonist, decreased GAC-mediated osteoblast differentiation in mBMMSCs through blocking the Wnt/β-catenin signaling pathway.
壳聚糖是一种天然存在的可生物降解和生物相容的聚合物，近年来已被用作食品添加剂、营养保健品和功能性食品。在这项研究中，通过自由基介导的接枝将没食子酸（GA）插入到普通壳聚糖（PC）上，制备了没食子酸接枝壳聚糖（GAC），并研究了其在鼠骨髓间充质干细胞（mBMMSCs）中的成骨作用。通过 1 H NMR 和 FT-IR 光谱对 PC 和 GAC 的结构进行了表征。通过 Folin-Ciocalteu 法，成功将 111 mg GA/g GAC 接枝到 PC 上。虽然 PC 和 GAC 均能促进碱性磷酸酶活性和矿化的增加，但 GAC 对这些因素的促进作用明显大于 PC，表明 GA 接枝到壳聚糖上增加了其成骨潜力。机制研究表明，GAC 能激活 Wnt1 和 Wnt3a mRNA 和蛋白表达，并增加β-catenin 向核内的易位，上调β-catenin 靶向基因的表达，包括 Runx2、osterix、I 型胶原和细胞周期蛋白 D1。此外，Wnt 拮抗剂 DKK-1 通过阻断 Wnt/β-catenin 信号通路，减少了 GAC 介导的 mBMMSCs 成骨分化。
