IGF-I in periodontal ligament has possibilities to accelerate the disintegration of HERS and the cell movements.

Research Project

Project/Area Number	17K11624
Research Category	Grant-in-Aid for Scientific Research (C)
Allocation Type	Multi-year Fund
Section	一般
Research Field	Morphological basic dentistry
Research Institution	Iwate Medical University
Principal Investigator	Fujiwara Naoki 岩手医科大学, 歯学部, 教授 (20190100)
Project Period (FY)	2017-04-01 – 2020-03-31
Project Status	Completed (Fiscal Year 2019)
Budget Amount *help	¥4,680,000 (Direct Cost: ¥3,600,000、Indirect Cost: ¥1,080,000) Fiscal Year 2019: ¥1,170,000 (Direct Cost: ¥900,000、Indirect Cost: ¥270,000) Fiscal Year 2018: ¥1,820,000 (Direct Cost: ¥1,400,000、Indirect Cost: ¥420,000) Fiscal Year 2017: ¥1,690,000 (Direct Cost: ¥1,300,000、Indirect Cost: ¥390,000)
Keywords	歯根形成 / Hertwig上皮鞘 / Malassezの上皮遺残 / 有細胞セメント質形成 / 上皮間葉転換 / CIL / IGF-I / 細胞遊走 / Her twig上皮鞘 / セメント質形成 / マラッセの上皮遺残
Outline of Final Research Achievements	Hertwig’s epithelial root sheath plays important roles in root development of molar tooth germs. Some phenomenon such as disintegration of HERS, cell migration into periodontal ligament were related with epithelial-mesenchyme transition and contact inhibition of locomotion. And formation of “cell rests of Malassez” and cellular cementogenesis results after these events. Although insulin-like growth factor (IGF)-I is noted as important factor induced cell growth in the early root formation, this factor is also accelerated these events in the late stage. Especially supplemented IGF-I increased gap formation of HERS cells and disintegration of basement membrane of the cell in organ culture system. Our findings indicated that IGF-I is one of the important regulatory factors throughout root formation.
Academic Significance and Societal Importance of the Research Achievements	歯根形成メカニズムの解明は実験環境の構築が難しいことから、不明な点が多く残っている。本研究の成果は、短根歯や長根歯の原因解明あるいは歯根の数を決める因子の解明、タウロドント歯の形成原因の解明、アペキシフィケーションなどにIGF-Iが重要な役割を果たす可能性を示した。また、上皮間葉転換やcontact inhibition of locomotionはこれまで神経堤細胞からの報告がほとんどであったが、新生仔を用いた本実験系は、生後マウスを用いることができ、従来より簡便に細胞ソースを入手することが可能となり、歯胚の形態形成の解明に留まらない実験系の構築にも貢献できたと考えている。