Suzuki Yoshimi, Nakajima Akira, Kawato Takayuki, Iwata Koichi, Motoyoshi Mitsuru, Shuler Charles F
Department of Orthodontics, Nihon University School of Dentistry, 1-8-13 Kanda Surugadai, Chiyoda-ku, Tokyo, 1018310, Japan.
Dental Research Center, Nihon University School of Dentistry, 1-8-13 Kanda Surugadai, Chiyoda-ku, Tokyo, 1018310, Japan.
J Oral Biol Craniofac Res. 2020 Apr-Jun;10(2):43-48. doi: 10.1016/j.jobcr.2020.01.002. Epub 2020 Jan 16.
TGF-β signaling is one of important function during palatal fusion. Three types of TGF-β receptor (TβR1, TβR2, and TβR3) have been identified, and play essential roles in mechanisms leading to palatal fusion. However, the balance between Smad-dependent/-independent signaling during palatal fusion with inhibited TβR1/2 functions is not fully understood. The objective of this study was to investigate palatal fusion via TGF-β signaling when TβR1 and TβR2, but not TβR3, were inhibited. In addition, the present study examined the functional balance between Smad-dependent/-independent signaling and related gene expression. Palatal organ cultures were treated with TβR1/2 inhibitor in vitro. Control palates were cultured without inhibitor. We observed histological phenotype of palatal fusion, and evaluation of expression pattern by Western blot or real time RT-PCR. Palatal organ cultures treated with the inhibitor did not fuse and the medial edge epithelium remained at embryonic 13 day +72 h in culture. The inhibitor decreased TβR1 and TβR2 expression by approximately 90%, but did not affect TβR3 expression. The expression of p-Smad2 and p-Smad3 was significantly decreased in treated palates compared with controls. The expression of p-Smad4 was slightly decreased in treated palates compared with controls. Smad-independent signaling was also affected by the inhibitor; p-ERK, p-JNK, and p-p38 expressions was significantly reduced in treated palates compared with controls. The expression of transcription factors (Runx1 and Msx1) and extracellular matrix proteins (MMP2/13) was also significantly decreased by inhibitor exposure. Treatment with TβR1/2 inhibitor altered the patterns of the Smad-dependent and -independent signaling pathways during palatal fusion.
转化生长因子-β（TGF-β）信号传导是腭融合过程中的重要功能之一。已鉴定出三种类型的TGF-β受体（TβR1、TβR2和TβR3），它们在腭融合机制中发挥着重要作用。然而，在TβR1/2功能受到抑制的腭融合过程中，Smad依赖/非依赖信号传导之间的平衡尚未完全了解。本研究的目的是在TβR1和TβR2（而非TβR3）受到抑制时，通过TGF-β信号传导来研究腭融合。此外，本研究还检测了Smad依赖/非依赖信号传导与相关基因表达之间的功能平衡。腭器官培养物在体外用TβR1/2抑制剂处理。对照腭在无抑制剂的情况下培养。我们观察了腭融合的组织学表型，并通过蛋白质免疫印迹或实时逆转录-聚合酶链反应评估表达模式。用抑制剂处理的腭器官培养物未融合，内侧边缘上皮在培养至胚胎第13天+72小时时仍保持原状。抑制剂使TβR1和TβR2的表达降低了约90%，但不影响TβR3的表达。与对照相比，处理后的腭中p-Smad2和p-Smad3的表达显著降低。与对照相比，处理后的腭中p-Smad4的表达略有降低。Smad非依赖信号传导也受到抑制剂的影响；与对照相比，处理后的腭中p-ERK、p-JNK和p-p38的表达显著降低。抑制剂处理还使转录因子（Runx1和Msx1）和细胞外基质蛋白（MMP2/13）的表达显著降低。TβR1/2抑制剂处理改变了腭融合过程中Smad依赖和非依赖信号通路的模式。
