Shimazaki Emi, Karakida Takeo, Yamamoto Ryuji, Kobayashi Saeko, Fukae Makoto, Yamakoshi Yasuo, Asada Yoshinobu
Department of Pediatric Dentistry, School of Dental Medicine, Tsurumi University, 2-1-3 Tsurumi, Tsurumi-ku, Yokohama 230-8501, Japan.
Department of Biochemistry and Molecular Biology, School of Dental Medicine, Tsurumi University, 2-1-3 Tsurumi, Tsurumi-ku, Yokohama 230-8501, Japan.
Int J Mol Sci. 2016 Dec 27;18(1):49. doi: 10.3390/ijms18010049.
The present study was performed to examine how transforming growth factor β (TGF-β) in root-surrounding tissues on deciduous teeth regulates the differentiation induction into odontoclasts during physiological root resorption. We prepared root-surrounding tissues with (R) or without (N) physiological root resorption scraped off at three regions (R1-R3 or N1-N3) from the cervical area to the apical area of the tooth and measured both TGF-β and the tartrate-resistant acid phosphatase (TRAP) activities. The TGF-β activity level was increased in N1-N3, whereas the TRAP activity was increased in R2 and R3. In vitro experiments for the receptor activator of nuclear factor-κB (NF-κB) ligand (RANKL)-mediated osteoclast differentiation revealed that proteins from N1-N3 and R1-R3 enhanced the TRAP activity in RAW264 cells. A genetic study indicated that the mRNA levels of TGF-β1 in N1 and N2 were significantly increased, and corresponded with levels of osteoprotegerin (OPG). In contrast, the expression level of RANKL was increased in R2 and R3. Our findings suggest that TGF-β is closely related to the regulation of OPG induction and RANKL-mediated odontoclast differentiation depending on the timing of RANKL and OPG mRNA expression in the root-surrounding tissues of deciduous teeth during physiological root resorption.
本研究旨在探讨乳牙牙根周围组织中的转化生长因子β（TGF-β）在生理性牙根吸收过程中如何调节破牙细胞的分化诱导。我们从牙齿颈部到根尖区域的三个部位（R1-R3或N1-N3）刮取有（R）或无（N）生理性牙根吸收的牙根周围组织，并测量TGF-β和抗酒石酸酸性磷酸酶（TRAP）的活性。N1-N3中的TGF-β活性水平升高，而R2和R3中的TRAP活性升高。针对核因子κB（NF-κB）配体（RANKL）介导的破骨细胞分化的体外实验表明，来自N1-N3和R1-R3的蛋白质增强了RAW264细胞中的TRAP活性。一项基因研究表明，N1和N2中TGF-β1的mRNA水平显著升高，且与骨保护素（OPG）水平相对应。相反，RANKL的表达水平在R2和R3中升高。我们的研究结果表明，在生理性牙根吸收过程中，根据乳牙牙根周围组织中RANKL和OPG mRNA表达的时间，TGF-β与OPG诱导的调节以及RANKL介导的破牙细胞分化密切相关。
