Division of Life and Pharmaceutical Sciences, Ewha Womans University, Seoul, Korea.
PLoS One. 2013;8(1):e54551. doi: 10.1371/journal.pone.0054551. Epub 2013 Jan 16.
Although the role of glycogen synthase kinase 3β (GSK3β) in osteogenic differentiation of bone marrow-derived mesenchymal stromal cells (BMSCs) is well-characterized as a negative regulator of β-catenin, its effect on osteogenesis of adipose-derived stromal cells (ADSCs) is poorly understood. Here, we show that GSK3β positively regulates osteogenic differentiation of murine ADSCs. Gain-of-function studies showed that GSK3β promotes in vitro osteogenesis of ADSCs. Regulation of GSK3β activity in ADSCs, either by small interfering RNA (siRNA)-mediated GSK3β silencing or by pharmacological inhibitors, blunted osteogenesis and the expression of osteogenic markers. Importantly, we demonstrated that transgenic mice, engineered to overexpress the constitutively active GSK3β (GSK3β-S9A) mutant, exhibited a marked increase in osteogenesis, whereas expression of the catalytically inactive GSK3β (GSK3β-K85A) in mice inhibits osteogenic differentiation. Molecular analyses showed that the enhanced osteoblast differentiation induced by GSK3β was mediated by downregulation of β-catenin. Remarkably, β-catenin silencing enhances osteogenesis and osteoblast marker gene expression such as alkaline phosphatase (ALP) and osterix. Taken together, these findings demonstrate a novel role for GSK3β in the regulation of osteogenic differentiation in ADSCs.
尽管糖原合酶激酶 3β（GSK3β）在骨髓间充质基质细胞（BMSCs）的成骨分化中作为β-连环蛋白的负调节剂的作用已得到很好的描述，但它对脂肪来源的基质细胞（ADSCs）成骨的影响知之甚少。在这里，我们表明 GSK3β 正向调节小鼠 ADSCs 的成骨分化。功能获得研究表明，GSK3β 促进 ADSCs 的体外成骨。通过小干扰 RNA（siRNA）介导的 GSK3β 沉默或通过药理学抑制剂调节 ADSCs 中的 GSK3β 活性，削弱了成骨作用和成骨标志物的表达。重要的是，我们证明了工程化表达组成型激活 GSK3β（GSK3β-S9A）突变体的转基因小鼠表现出明显增加的成骨作用，而在小鼠中表达催化失活的 GSK3β（GSK3β-K85A）则抑制成骨分化。分子分析表明，GSK3β 诱导的成骨细胞分化增强是通过下调β-连环蛋白介导的。值得注意的是，β-连环蛋白沉默增强了成骨作用和成骨细胞标记基因的表达，如碱性磷酸酶（ALP）和osterix。总之，这些发现表明 GSK3β 在调节 ADSCs 中的成骨分化中具有新的作用。
