Mineralized Tissue Research Unit and Department of Anatomy, Faculty of Dentistry, Chulalongkorn University, Bangkok 10330, Thailand.
Mineralized Tissue Research Unit and Department of Anatomy, Faculty of Dentistry, Chulalongkorn University, Bangkok 10330, Thailand; Craniofacial Genetics and Stem Cell Research Group, Faculty of Dentistry, Chulalongkorn University, Bangkok 10330, Thailand.
Arch Oral Biol. 2017 Oct;82:47-54. doi: 10.1016/j.archoralbio.2017.05.020. Epub 2017 Jun 1.
Different mechanical stimuli regulate behaviors of various cell types, including osteoblasts, osteocytes, and periodontal ligament fibroblasts. Notch signaling participates in the mechanical stress-regulated cell responses. The present study investigated the regulation of Notch target gene and sclerostin (Sost) expression in murine pre-osteoblast cell line (MC3T3-E1) under intermittent compressive stress.
MC3T3-E1 were subjected to the intermittent compressive force under the computerized controlled machine. In some experiments, cells were pretreated with chemical inhibitors for Notch and transforming growth factor (TGF)-β signaling prior to mechanical stimuli. To evaluate role of Notch signaling in MC3T3-E1 cells under unloaded condition, cells were seeded on indirect immobilized Notch ligand (Jagged1). Gene expression was determined using real-time quantitative polymerase chain reaction.
The intermittent compressive stress significantly upregulated Notch target gene expression (Hes Family BHLH transcription factor 1; Hes1 and Hairy/enhancer-of-split related with YRPW motif protein1; Hey1). The intermittent stress-induced Hes1 and Hey1 mRNA expression could be inhibited by a γ-secretase inhibitor (DAPT) or a TGF-β superfamily type I activing receptor-like kinase receptors inhibitor (SB431542). The results imply that intermittent compressive stress regulates Notch signaling via TGF-β pathway. Further, the intermittent compressive stress reduced Sost mRNA expression and this phenomenon could be rescued by a DAPT pretreatment, implying the involvement of Notch signaling. However, activation of Notch signaling under the unloaded condition resulted in the increase of Sost expression and the reduction of osteogenic marker genes.
These results imply the involvement of Notch signaling in the homeostasis maintaining of osteogenic cells under mechanical stress stimuli.
不同的机械刺激调节各种细胞类型的行为，包括成骨细胞、骨细胞和牙周韧带成纤维细胞。Notch 信号参与机械应激调节的细胞反应。本研究探讨了 Notch 靶基因和骨硬化蛋白（Sost）在鼠前成骨细胞系（MC3T3-E1）在间歇压缩力下的表达调控。
MC3T3-E1 在计算机控制的机器下受到间歇压缩力。在一些实验中，细胞在机械刺激前用 Notch 和转化生长因子（TGF）-β信号的化学抑制剂预处理。为了评估 Notch 信号在未加载条件下对 MC3T3-E1 细胞的作用，细胞接种在间接固定的 Notch 配体（Jagged1）上。采用实时定量聚合酶链反应测定基因表达。
间歇压缩力显著上调 Notch 靶基因表达（Hes 家族 BHLH 转录因子 1；Hes1 和 Hairy/enhancer-of-split 相关与 YRPW 基序蛋白 1；Hey1）。间歇压诱导的 Hes1 和 Hey1 mRNA 表达可被γ-分泌酶抑制剂（DAPT）或 TGF-β超家族 I 型激活受体样激酶受体抑制剂（SB431542）抑制。结果表明，间歇压缩力通过 TGF-β途径调节 Notch 信号。此外，间歇压缩力降低了 Sost mRNA 的表达，而 DAPT 预处理可挽救这种现象，表明 Notch 信号的参与。然而，在无负荷条件下激活 Notch 信号导致 Sost 表达增加和成骨标记基因减少。
这些结果表明，Notch 信号参与了机械应激刺激下成骨细胞的内稳态维持。
