Department of Stomatology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
Department of Stomatology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
J Dent. 2019 Mar;82:91-97. doi: 10.1016/j.jdent.2019.01.015. Epub 2019 Feb 1.
Osteoclast differentiation is regulated by transcriptional, post-transcriptional and post-translational mechanisms. Micro-ribonucleic acids (miRNAs) are 20-24 nucleotides long non-coding RNAs involved in post-translational regulation of gene expressions during osteoclast differentiation. The objective of the present study was to investigate the role played by the miRNA, miR-338-3p, in osteoclastogenesis.
Osteoclastogenesis was induced in murine RAW264.7 cells using M-CSF and RANKL. The differentiated cells were harvested at designated times for TRAP staining and detection of designated gene expressions. A synthetic miR-338-3p mimic or its inhibitor was transfected into RAW264.7 cells prior to the induction of osteoclastogenesis. The effects of mimic or inhibitor on osteoclastogenesis were examined by qRT-PCR and TRAP staining. Bioinformatic analysis and luciferase activity were performed to identify the relationship between miR-338-3p and the transcription factor MafB. The miR-338-3p mimic and MafB siRNA were co-transfected into RAW264.7 cells to evaluate the cross-talk between miR-338-3p and MafB.
miR-338-3p was increased significantly during osteoclast differentiation. Overexpression of miR-338-3p promoted osteoclastogenesis while its inhibition had the opposite effect. Bioinformatic analysis and dual luciferase assays indicated that miR-338-3p targeted MafB to repress its gene expression. MafB knockdown by RNA silencing blocked the promotional effect of miR-338-3p on osteoclast differentiation.
Because miR-338-3p is crucial for osteoclastic differentiation via targeting of the transcription factor MafB, inhibition of this miRNA represents a potential strategy for modulating osteoporosis in an aging population. CLINICAL SIGNIfiCANCE: Understanding the role played by miR-338-3p in osteoclast differentiation bridges the gap between the pathogenesis of osteoporosis and the quest for novel therapeutics to reduce the risk of bone fracture associated with this global disease.
破骨细胞分化受转录、转录后和翻译后机制调控。微小 RNA（miRNA）是 20-24 个核苷酸长的非编码 RNA，参与破骨细胞分化过程中的基因表达转录后调控。本研究旨在探讨 miRNA-338-3p 在破骨细胞分化中的作用。
用 M-CSF 和 RANKL 诱导鼠 RAW264.7 细胞的破骨细胞分化。在指定时间收获分化细胞，进行 TRAP 染色和指定基因表达检测。在诱导破骨细胞分化之前，将合成的 miR-338-3p 模拟物或其抑制剂转染到 RAW264.7 细胞中。通过 qRT-PCR 和 TRAP 染色检测模拟物或抑制剂对破骨细胞分化的影响。进行生物信息学分析和荧光素酶活性测定，以确定 miR-338-3p 与转录因子 MafB 之间的关系。将 miR-338-3p 模拟物和 MafB siRNA 共转染到 RAW264.7 细胞中，以评估 miR-338-3p 与 MafB 之间的交叉对话。
miR-338-3p 在破骨细胞分化过程中显著增加。miR-338-3p 的过表达促进破骨细胞分化，而其抑制则产生相反的效果。生物信息学分析和双荧光素酶测定表明，miR-338-3p 靶向 MafB 以抑制其基因表达。通过 RNA 沉默敲低 MafB 阻断了 miR-338-3p 对破骨细胞分化的促进作用。
因为 miR-338-3p 通过靶向转录因子 MafB 对破骨细胞分化至关重要，所以抑制这种 miRNA 可能是调节老龄化人群骨质疏松症的一种潜在策略。临床意义：了解 miR-338-3p 在破骨细胞分化中的作用，填补了骨质疏松症发病机制与寻找降低与这种全球性疾病相关的骨折风险的新型治疗方法之间的空白。
