1 The State Key Laboratory Breeding Base of Basic Science of Stomatology & Key Laboratory for Oral Biomedical Engineering of Ministry of Education, School & Hospital of Stomatology, Wuhan University, Wuhan, China.
2 Department of Periodontology, School & Hospital of Stomatology, Wuhan University, Wuhan, China.
J Dent Res. 2017 Nov;96(12):1430-1437. doi: 10.1177/0022034517718790. Epub 2017 Jul 10.
Periodontitis is a prevalent and chronic inflammatory disease that is interrelated with systemic health. Periodontitis can be promoted by tumor necrosis factor α (TNF-α). Cementum, a vital part of the periodontium, is a bone-like mineralized tissue that is produced by cementoblasts. Our laboratory previously revealed that TNF-α inhibits cementoblast differentiation and mineralization. However, how TNF-α modulates cementoblast differentiation and mineralization remains largely unknown. MicroRNA-155 (miR-155) is induced and regulates TNF-α-inhibited osteogenic differentiation. In this study, we found that miR-155-3p was increased during TNF-α-stimulated OCCM-30 cells and involved in cementoblast differentiation and mineralization. Overexpression of miR-155-3p suppressed cementoblast mineralization. Bioinformatics analysis revealed that potassium channel tetramerization domain containing 1 ( Kctd1) is a candidate target gene of miR-155-3p. Moreover, miR-155-3p overexpression suppressed KCTD1 levels. Meanwhile, its knockdown increased KCTD1 expression. Transfection with miR-155-3p also inhibited the luciferase activity of 3'-untranslated regions in the Kctd1 wild type but not the mutant. These data indicated that Kctd1 is a direct and novel target of miR-155-3p. The Wnt signaling pathway inhibits cementoblast differentiation, and we further demonstrated that miR-155-3p partially modulates cementoblast differentiation through the canonical Wnt signaling pathway. In addition to the gain/loss function assay of miR-155-3p, the luciferase activity assay of canonical Wnt signaling was performed. The assays revealed that miR-155-3p increased β-catenin-mediated transcriptional activation. Overall, our data clarified that miR-155-3p mediated TNF-α-inhibited cementoblast differentiation by targeting Kctd1, at least partially through canonical Wnt signaling pathway. These findings reveal the expanded function of miRNAs in cementoblast differentiation and mineralization.
牙周炎是一种普遍存在的慢性炎症性疾病，与全身健康有关。肿瘤坏死因子-α（TNF-α）可促进牙周炎的发生。牙骨质是牙周组织的重要组成部分，是一种由成牙骨质细胞产生的类似骨的矿化组织。我们的实验室之前已经揭示，TNF-α抑制成牙骨质细胞的分化和矿化。然而，TNF-α如何调节成牙骨质细胞的分化和矿化在很大程度上仍然未知。微小 RNA-155（miR-155）被诱导并调节 TNF-α抑制的成骨分化。在本研究中，我们发现 TNF-α刺激 OCCM-30 细胞时 miR-155-3p 增加，并参与成牙骨质细胞分化和矿化。miR-155-3p 的过表达抑制了成牙骨质细胞的矿化。生物信息学分析显示，钾通道四聚化结构域包含蛋白 1（Kctd1）是 miR-155-3p 的候选靶基因。此外，miR-155-3p 的过表达抑制了 KCTD1 的水平。同时，其敲低增加了 KCTD1 的表达。miR-155-3p 的转染还抑制了 Kctd1 野生型但不抑制突变型 3'非翻译区的荧光素酶活性。这些数据表明 Kctd1 是 miR-155-3p 的直接和新型靶基因。Wnt 信号通路抑制成牙骨质细胞的分化，我们进一步证明 miR-155-3p 通过经典的 Wnt 信号通路部分调节成牙骨质细胞的分化。除了 miR-155-3p 的增益/损耗功能测定外，还进行了经典 Wnt 信号的荧光素酶活性测定。这些测定表明，miR-155-3p 增加了β-连环蛋白介导的转录激活。总的来说，我们的数据阐明了 miR-155-3p 通过靶向 Kctd1 介导 TNF-α抑制的成牙骨质细胞分化，至少部分通过经典的 Wnt 信号通路。这些发现揭示了 miRNA 在成牙骨质细胞分化和矿化中的扩展功能。
