BACKGROUND Long non-coding RNAs (lncRNAs) have been widely known to have an appreciable effect in physiology and pathology. In tooth regeneration, periodontal ligament stem cells (PDLSCs) are regarded as a key effector, whereas, how lncRNA acts in the osteogenic differentiation of PDLSCs have not been completely understood. This study aims to find out the relationship between lncRNA DANCR and the proliferation and osteogenic differentiation of PDLSCs. METHODS Microarray was used to observe the different expression of lncRNAs in differentiated and undifferentiated PDLSCs. And then osteogenic-related lncRNA, DANCR was screened out. Its effects on proliferation and osteogenic differentiation was explored by constructing an overexpression and inhibition model. qRT-PCR was used to detect the mRNA expression of osteogenesis related genes. MTT assay was performed to assess the effects of DANCR on cell growth curve. To quantify the effects of DANCR on osteogenic differentiation of PDLSCs, ALP staining and alizarin red was performed in basic culture medium and osteogenic medium. Data were statistically processed. RESULTS Compared with the undifferentiated PDLSCs, the alizarin red staining level was higher in differentiated PDLSCs. And the expressions of osteogenic differentiation marker genes Runt-related transcription factor 2 (Runx2), osteocalcin (OCN) and bone morphogenetic protein (BMP-2) were significantly increased in the differentiated PDLSCs. Furthermore, we noticed that comparing with control groups, the expression of lncRNA DANCR decreases markedly in osteogenically induced PDLSCs. DANCR promoted proliferation of PDLSCs, as evidenced by cell viability. Further investigation has proven that the downregulation of DANCR shows in the calcium sediment forming, alkaline phosphatase (ALP) activation and some osteogenic-related gene markers' upregulation including Runx2, OCN and BMP-2, which finally results in the osteogenic differentiation of PDLSCs following the transfection and induction. Conversely, DANCR upregulation was shown to repress the osteogenic differentiation potential of PDLSCs. CONCLUSIONS The osteogenic differentiation of PDLSCs has proven to related to the down regulation of lncRNA DANCR. And this paper throws light on the effects of DANCR in the process of PDLSCs' osteogenic differentiation.

中文翻译：

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lncRNA DANCR的下调促进牙周膜干细胞的成骨分化。

背景技术众所周知，长的非编码RNA（lncRNA）在生理和病理学中具有明显的作用。在牙齿再生中，牙周膜干细胞（PDLSC）被认为是关键效应物，然而，lncRNA在PDLSCs的成骨分化中的作用尚不完全清楚。本研究旨在发现lncRNA DANCR与PDLSCs的增殖和成骨分化之间的关系。方法使用微阵列芯片观察分化和未分化的PDLSCs中lncRNA的不同表达。然后筛选出与成骨相关的lncRNA，DANCR。通过构建过表达和抑制模型来探索其对增殖和成骨分化的影响。用qRT-PCR检测成骨相关基因的mRNA表达。进行MTT测定以评估DANCR对细胞生长曲线的影响。为了量化DANCR对PDLSCs成骨分化的影响，在碱性培养基和成骨培养基中进行了ALP染色和茜素红。对数据进行统计处理。结果与未分化的PDLSC相比，分化的PDLSC中茜素红染色水平较高。在分化的PDLSCs中，成骨分化标记基因Runt相关转录因子2（Runx2），骨钙素（OCN）和骨形态发生蛋白（BMP-2）的表达显着增加。此外，我们注意到与对照组相比，在成骨诱导的PDLSCs中，lncRNA DANCR的表达明显降低。DANCR促进了PDLSC的增殖，如细胞活力所证明。进一步的研究证明，DANCR的下调表现在钙沉积物形成，碱性磷酸酶（ALP）活化和一些成骨相关基因标志物的上调，包括Runx2，OCN和BMP-2，最终导致PDLSCs的成骨分化。转染和诱导。相反，DANCR上调显示抑制PDLSCs的成骨分化潜能。结论已证明PDLSC的成骨分化与lncRNA DANCR的下调有关。并阐明了DANCR在PDLSCs成骨分化过程中的作用。上调表达，包括Runx2，OCN和BMP-2，最终在转染和诱导后导致PDLSC的成骨分化。相反，DANCR上调显示抑制PDLSCs的成骨分化潜能。结论已证明PDLSC的成骨分化与lncRNA DANCR的下调有关。并阐明了DANCR在PDLSCs成骨分化过程中的作用。上调，包括Runx2，OCN和BMP-2，最终导致转染和诱导后PDLSC的成骨分化。相反，DANCR上调显示抑制PDLSCs的成骨分化潜能。结论已证明PDLSC的成骨分化与lncRNA DANCR的下调有关。并阐明了DANCR在PDLSCs成骨分化过程中的作用。