Abstract

Osteoclast differentiation-mediates bone resorption is the key biological basis of orthodontic treatment while the specific mechanism of osteoclastogenesis remains unclear. This study aims to explore the underlying mechanism of the osteoclast differentiation from the perspective of long non-coding RNA (LncRNA). In the present study, the osteoclast differentiation of CD14⁺ peripheral blood mononuclear cells (PBMCs) was induced by recombinant human macrophage colony-stimulating factor (M-CSF) and receptor activator of nuclear factor κB ligand (RANKL), and LncRNA TUG1 expression was dramatically elevated during this process. Functionally, the silence of TUG1 in CD14⁺ PBMCs decreased tartrate-resistant acid phosphatase (TRAP)-positive cell numbers and the protein levels of TRAP, nuclear factor of activated T cell c1 (NFATc1), and osteoclast-associated receptor (OSCAR), whereas increased V‐maf musculoaponeurotic fibrosarcoma oncogene homolog B (MafB) protein level. The subsequent experiments confirmed that TUG1 lessened the MafB protein level via accelerating its degradation. Then, the interference of MafB reversed the inhibitory effect of si-TUG1 on osteoclastogenesis, including increased the TRAP-positive cell numbers and up-regulated the protein levels of osteoclast markers. Finally, the in vivo experiments displayed that the increased TUG1 levels could promote tooth movement and bone resorption via facilitating osteoclast differentiation in the rat model of orthodontic tooth movement. In summary, TUG1 overexpressed during the process of osteoclast differentiation and positively regulated osteoclast differentiation by targeting MafB.

摘要

破骨细胞分化介导的骨吸收是正畸治疗的关键生物学基础，而破骨细胞发生的具体机制尚不清楚。本研究旨在从长链非编码RNA（LncRNA）的角度探讨破骨细胞分化的潜在机制。本研究通过重组人巨噬细胞集落刺激因子（M-CSF）和核因子κB配体受体激活剂（RANKL）诱导CD14 ⁺外周血单核细胞（PBMCs）的破骨细胞分化，LncRNA TUG1表达为在这个过程中急剧上升。在功能上，CD14 ⁺中 TUG1 的沉默PBMC 降低了抗酒石酸酸性磷酸酶 (TRAP) 阳性细胞数量和 TRAP、活化 T 细胞 c1 核因子 (NFATc1) 和破骨细胞相关受体 (OSCAR) 的蛋白质水平，而增加了 V-maf 肌肉腱膜纤维肉瘤癌基因同源物B (MafB) 蛋白水平。随后的实验证实，TUG1通过加速降解来降低 MafB 蛋白水平。然后，MafB 的干扰逆转了 si-TUG1 对破骨细胞生成的抑制作用，包括增加 TRAP 阳性细胞数量和上调破骨细胞标志物的蛋白质水平。最后，体内实验显示，增加的TUG1水平能促进牙齿移动和骨吸收通过促进正畸牙齿运动大鼠模型中的破骨细胞分化。总之，TUG1 在破骨细胞分化过程中过表达，并通过靶向 MafB 正向调节破骨细胞分化。