Chang Maolin, Lin Heng, Fu Haidi, Wang Beike, Han Guangli, Fan Mingwen
State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) and Key Laboratory of Oral Biomedicine of Ministry of Education (KLOBM), School and Hospital of Stomatology, Wuhan University, Wuhan, China.
Department of Orthodontics, School and Hospital of Stomatology, Wuhan University, Wuhan, China.
J Cell Physiol. 2017 Dec;232(12):3762-3774. doi: 10.1002/jcp.25856. Epub 2017 May 3.
Osteogenic differentiation and bone formation are tightly regulated by several factors, including microRNAs (miRNAs). However, miRNA expression patterns and function during mechanical loading-induced osteogenic differentiation of human periodontal ligament cells (PDLCs) remain unclear. Here, we investigated the differential expression of miRNA-195-5p in the periodontal tissues of mice under orthodontic mechanical loading and in primary human PDLCs exposed to a simulated tension strain. The miR-195-5p was observed to be down-regulated and negatively correlated with osteogenic differentiation. Overexpression of miR-195-5p significantly inhibited PDLC differentiation under cyclic tension strain (CTS), whereas the functional inhibition of miR-195-5p yielded an opposite effect. Further experiments confirmed that WNT family member 3A (WNT3A), fibroblast growth factor 2 (FGF2), and bone morphogenetic protein receptor-1A (BMPR1A), proteins important for osteogenic activity and stability, were direct targets of miR-195-5p. Mechanical loading increased the WNT3A, FGF2, and BMPR1A protein levels, while miR-195-5p inhibited WNT3A, FGF2, and BMPR1A protein expression. WNT, FGF, and BMP signaling were involved in osteogenic differentiation of PDLCs under CTS. Further study confirmed that reintroduction of WNT3A and BMPR1A can rescue the inhibition of miR-195-5p on osteogenic differentiation of PDLCs. Our findings are the first to demonstrate that miR-195-5p is a mechanosensitive gene that plays an important role in mechanical loading-induced osteogenic differentiation and bone formation.
成骨分化和骨形成受到多种因素的严格调控，包括微小RNA（miRNA）。然而，在机械加载诱导人牙周膜细胞（PDLCs）成骨分化过程中，miRNA的表达模式和功能仍不清楚。在此，我们研究了正畸机械加载下小鼠牙周组织以及暴露于模拟拉伸应变的原代人PDLCs中miRNA-195-5p的差异表达。观察到miR-195-5p表达下调且与成骨分化呈负相关。miR-195-5p过表达显著抑制循环拉伸应变（CTS）下PDLCs的分化，而miR-195-5p的功能抑制则产生相反的效果。进一步实验证实，对成骨活性和稳定性重要的蛋白质WNT家族成员3A（WNT3A）、成纤维细胞生长因子2（FGF2）和骨形态发生蛋白受体-1A（BMPR1A）是miR-195-5p的直接靶点。机械加载增加了WNT3A、FGF2和BMPR1A蛋白水平，而miR-195-5p抑制WNT3A、FGF2和BMPR1A蛋白表达。WNT、FGF和BMP信号通路参与了CTS下PDLCs的成骨分化。进一步研究证实，重新引入WNT3A和BMPR1A可以挽救miR-195-5p对PDLCs成骨分化的抑制作用。我们的研究结果首次证明miR-195-5p是一种机械敏感基因，在机械加载诱导的成骨分化和骨形成中起重要作用。
