基于Wnt/β-catenin信号通路的γ-生育三烯酚诱导成骨细胞分化的机制研究

Osteoporosis is a serious public health problem characterized by low bone mass and microarchitectural deterioration of bone tissue, leading to enhanced bone fragility and a consequent increase in fracture risk. The increase of osteoblast differentiation is one of the key to prevent and treat osteoporosis. Previous in vivo studies showed that γ-tocotrienol (γ-T3) exhibits a strong osteogenic activity. However, the effects of γ-T3 on osteoblast function in vitro and its mechanism have not been reported. The results from our laboratory have demonstrated that and alkaline phosphatase (ALP) activity was enhanced after induction with γ-T3 at 72 h (ALP activity is an early phenotypic marker for osteogenic differentiation of osteoblast). However, the detail role of γ-T3 induced MC3T3-E1 cells differentiation and its mechanisms are not fully understood. In this study, the effect of γ-T3 on the differentiation of MC3T3-E1 cells was investigated. We also analyzed the role of Wnt/β-catenin signaling pathways in γ-T3 regulated the viability and differentiation of osteoblastic MC3T3-E1 cells. The results of the study will be able to provide theoretical support that for the application in food industry production of γ-T3 as functional food ingredients for the prevention of osteoporosis, and will have huge significance for development of functional food products in relation to osteoporosis.

骨质疏松症已成为一个严重的公共健康问题，提高成骨细胞的分化水平是预防骨质疏松症的关键之一。诸多体内研究证实食源性植物化学物γ-生育三烯酚具有优良的成骨活性，是一种全新的具有预防和改善骨质疏松症潜力的天然活性物质。然而，有关γ-生育三烯酚成骨活性的作用机制尚不明确。我们的前期研究表明γ-生育三烯酚可有效地促进成骨细胞分化的早期标志物碱性磷酸酶（ALP）的活性。本项目在前期研究工作基础之上，采用体外细胞培养和分子生物学方法详细阐明γ-生育三烯酚对成骨细胞的诱导分化作用，并应用阻断剂分析在骨形成中起核心作用的Wnt/β-catenin信号通路在γ-生育三烯酚促进成骨细胞分化功能中的作用，在细胞和分子水平上较为系统的阐明γ-生育三烯酚成骨活性的作用机理。该研究结果将为γ-生育三烯酚作为预防骨质疏松症的功能因子在食品领域应用提供重要的理论基础，对于促进和改善骨骼健康的功能性食品的开发具有指导意义。

骨质疏松症已成为世界性公共健康问题，而目前市场上预防和改善骨质疏松的药物存在较大的副作用或者效果不佳，因此研究和开发具有促进骨骼健康、预防和改善骨质疏松的天然活性成分以及功能性食品具有良好的应用前景。γ-生育三烯酚属于异戊二烯植物化合物，诸多动物研究证明γ-生育三烯酚对骨代谢和骨重建有促进作用，然而关于其在细胞水平上的机制尚未阐明。本研究证明低剂量（2-8 μmol/L）的γ-生育三烯酚对MC3T3-E1细胞的增殖与分化具有诱导作用，发现4 μmol/L的γ-生育三烯酚能够通过调节β-catenin蛋白的表达量及其在细胞内的分布对Wnt/β-catenin信号通路产生激活作用；应用阻断剂分析明确了γ-生育三烯酚可以通过Wnt/β-catenin信号通路发挥促进MC3T3-E1细胞增殖与分化的作用，并揭示β-catenin是γ-生育三烯酚对该信号通路的作用靶点。