Takeshita Nobuo, Hasegawa Masakazu, Sasaki Kiyo, Seki Daisuke, Seiryu Masahiro, Miyashita Shunro, Takano Ikuko, Oyanagi Toshihito, Miyajima Yuki, Takano-Yamamoto Teruko
Division of Orthodontics and Dentofacial Orthopedics, Graduate School of Dentistry, Tohoku University, 4-1 Seiryo-machi, Aoba-ku, Sendai, Miyagi, 980-8575, Japan.
J Bone Miner Metab. 2017 Jan;35(1):40-51. doi: 10.1007/s00774-016-0737-z. Epub 2016 Jan 29.
Sutures are fibrous tissues that connect bones in craniofacial skeletal complexes. Cranio- and dentofacial skeletal deformities in infant and adolescent patients can be treated by applying tensile force to sutures to induce sutural bone formation. The early gene expression induced by mechanical stress is essential for bone formation in long bones; however, early gene expression during sutural bone formation induced by tensile force is poorly characterized. In vivo studies are essential to evaluate molecular responses to mechanical stresses in heterogeneous cell populations, such as sutures. In this paper we examined in vivo early gene expression and the underlying regulatory mechanism for this expression in tensile-force-applied cranial sutures, focusing on genes involved in vascularization. Tensile force upregulated expression of vascular factors, such as vascular endothelial growth factor (Vegf) and endothelial cell markers, in sutures within 3 h. The expression of connective tissue growth factor (Ctgf) and Rho-associated coiled-coil containing protein kinase 2 (Rock2) was also upregulated by tensile force. A CTGF-neutralizing antibody and the ROCK inhibitor, Y-27632, abolished tensile-force-induced Vegf expression. Moreover, tensile force activated extracellular signal-related kinase 1/2 (ERK1/2) signaling in sagittal sutures, and the ERK1/2 inhibitor, U0126, partially inhibited tensile-force-induced Ctgf expression. These results indicate that tensile force induces in vivo gene expression associated with vascularization early in tensile-force-induced sutural bone formation. Moreover, the early induction of Vegf gene expression is regulated by CTGF and ROCK2.
缝线是连接颅面骨骼复合体中骨骼的纤维组织。婴幼儿和青少年患者的颅面骨骼畸形可通过对缝线施加拉力诱导缝线骨形成来治疗。机械应力诱导的早期基因表达对长骨的骨形成至关重要；然而，拉力诱导缝线骨形成过程中的早期基因表达特征尚不明确。体内研究对于评估异质性细胞群体（如缝线）对机械应力的分子反应至关重要。在本文中，我们研究了体内早期基因表达以及在施加拉力的颅骨缝线中这种表达的潜在调控机制，重点关注与血管生成相关的基因。拉力在3小时内上调了缝线中血管因子（如血管内皮生长因子（Vegf））和内皮细胞标志物的表达。结缔组织生长因子（Ctgf）和含Rho相关卷曲螺旋的蛋白激酶2（Rock2）的表达也因拉力而上调。CTGF中和抗体和ROCK抑制剂Y-27632消除了拉力诱导的Vegf表达。此外，拉力激活了矢状缝中的细胞外信号调节激酶1/2（ERK1/2）信号通路，ERK1/2抑制剂U0126部分抑制了拉力诱导的Ctgf表达。这些结果表明，拉力在拉力诱导的缝线骨形成早期诱导体内与血管生成相关的基因表达。此外，Vegf基因表达的早期诱导受CTGF和Rock2调控。
