Bone fractures are common impact injuries typically resolved through natural processes of osteogenic regeneration and bone remodeling, restoring the biological and mechanical function. However, dysfunctionality in bone healing and repair often arises in the context of aging-related chronic disorders, such as Alzheimer's disease (AD). There is unmet need for effective pharmacological modulators of osteogenic differentiation and an opportunity to probe the complex links between bone biology and cognitive disorders. We previously discovered the small molecule DIPQUO, which promotes osteoblast differentiation and bone mineralization in mouse and human cell culture models, and in zebrafish developmental and regenerative models. Here, we examined the detailed function of this molecule. First, we used kinase profiling, cellular thermal shift assays, and functional studies to identify glycogen synthase kinase 3-beta (GSK3-β) inhibition as a mechanism of DIPQUO action. Treatment of mouse C2C12 myoblasts with DIPQUO promoted alkaline phosphatase expression and activity, which could be enhanced synergistically by treatment with other GSK3-β inhibitors. Suppression of the expression or function of GSK3-β attenuated DIPQUO-dependent osteogenic differentiation. In addition, DIPQUO synergized with GSK3-β inhibitors to stimulate expression of osteoblast genes in human multipotent progenitors. Accordingly, DIPQUO promoted accumulation and activation of β-catenin. Moreover, DIPQUO suppressed activation of tau microtubule-associated protein, an AD-related effector of GSK3-β signaling. Therefore, DIPQUO has potential as both a lead candidate for bone therapeutic development and a pharmacological modulator of GSK3-β signaling in cell culture and animal models of disorders including AD.

中文翻译：

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小分子 DIPQUO 通过抑制糖原合酶激酶 3-β 信号传导促进成骨分化。

骨折是常见的冲击损伤，通常通过成骨再生和骨重建的自然过程来解决，恢复生物和机械功能。然而，骨骼愈合和修复的功能障碍通常出现在与衰老相关的慢性疾病的背景下，例如阿尔茨海默病 (AD)。对有效的成骨分化药理学调节剂的需求尚未得到满足，并且有机会探索骨生物学和认知障碍之间的复杂联系。我们之前发现了小分子 DIPQUO，它在小鼠和人类细胞培养模型以及斑马鱼发育和再生模型中促进成骨细胞分化和骨矿化。在这里，我们检查了该分子的详细功能。首先，我们使用激酶分析、细胞热位移分析、和功能研究，以确定作为 DIPQUO 作用机制的糖原合酶激酶 3-β (GSK3-β) 抑制。用 DIPQUO 处理小鼠 C2C12 成肌细胞可促进碱性磷酸酶的表达和活性，这可以通过与其他 GSK3-β 抑制剂处理协同增强。GSK3-β 表达或功能的抑制减弱了 DIPQUO 依赖性成骨分化。此外，DIPQUO 与 GSK3-β 抑制剂协同作用以刺激人类多能祖细胞中成骨细胞基因的表达。因此，DIPQUO 促进了 β-catenin 的积累和活化。此外，DIPQUO 抑制 tau 微管相关蛋白（GSK3-β 信号传导的 AD 相关效应子）的激活。因此，