State Key Laboratory of Oral Diseases, Sichuan University, Chengdu 610041, China.
Mol Cells. 2012 Jun;33(6):611-6. doi: 10.1007/s10059-012-0053-y. Epub 2012 May 17.
Osteocytes that have a dendritic appearance are widely believed to form a complex cellular network system and play crucial roles in mechanotransduction as a principal bone mechanosensor, which is the basis of their neuronallike biology, as previously reported. Neuropeptide Y (NPY) and reelin mRNA, which are brain-specific neurogenic markers, have been identified in osteocytes. However, changes in the production of NPY and reelin in response to specific biochemical stimulation are unknown. In this study, we investigated the in vitro effect of corticosterone, one of the endogenous glucocorticoids, on the expression of NPY and reelin in the MLO-Y4 osteocyte cell line. Cells were treated with corticosterone at different concentrations (10(-9) M-10(-5) M) for 1, 3, 6, 12 and 24 h. As revealed, corticosterone reduced the MLO-Y4 cell viability and proliferation in a dose- and time-dependent manner based on an MTT assay and a Vi-CELL analyzer. The cells were then incubated with corticosterone (10(-6) μM), and the NPY and reelin expression levels were detected at 1, 3, 6, 12 and 24 h using real-time PCR and Western blot analysis. These results demonstrated that at the gene and the protein levels, corticosterone significantly upregulated the NPY and reelin expression in a time-dependent manner. The application of a glucocorticoid receptor antagonist, RU486, reversed the reduced cell viability and the increased expression of NPY and reelin that were caused by corticosterone. To the best of our knowledge, this is the first report to verify that corticosterone regulates the NPY and reelin expression in osteocytes.
被广泛认为呈树突状的骨细胞形成了一个复杂的细胞网络系统，并作为主要的骨机械感受器在机械转导中发挥关键作用，这是它们类神经元生物学的基础，正如之前报道的那样。神经肽 Y（NPY）和 reelin mRNA 已在骨细胞中被鉴定出来，它们是大脑特异性神经发生标记物。然而，NPY 和 reelin 的产生在对特定生化刺激的反应中的变化尚不清楚。在这项研究中，我们研究了内源性糖皮质激素之一皮质酮对 MLO-Y4 骨细胞系中 NPY 和 reelin 表达的体外影响。细胞用不同浓度（10（-9）M-10（-5）M）的皮质酮处理 1、3、6、12 和 24 h。结果表明，根据 MTT 测定和 Vi-CELL 分析仪，皮质酮以剂量和时间依赖的方式降低 MLO-Y4 细胞活力和增殖。然后将细胞与皮质酮（10（-6）μM）孵育，并在 1、3、6、12 和 24 h 时使用实时 PCR 和 Western blot 分析检测 NPY 和 reelin 的表达水平。这些结果表明，在基因和蛋白质水平上，皮质酮以时间依赖的方式显著上调 NPY 和 reelin 的表达。糖皮质激素受体拮抗剂 RU486 的应用逆转了皮质酮引起的细胞活力降低和 NPY 和 reelin 表达增加。据我们所知，这是首次报道证实皮质酮调节骨细胞中的 NPY 和 reelin 表达。
