title: FGF-9 accelerates epithelial invagination for ectodermal organogenesis in real time bioengineered organ manipulation.
abstract: BACKGROUND
  Epithelial invagination is important for initiation of ectodermal organogenesis. Although many factors regulate ectodermal organogenesis, there is not any report about their functions in real-time study. Electric cell-substrate impedance sensing (ECIS), a non-invasive, real-time surveillance system, had been used to detect changes in organ cell layer thickness through quantitative monitoring of the impedance of a cell-to-microelectrode interface over time. It was shown to be a good method for identifying significant real-time changes of cells. The purpose of this study is to establish a combined bioengineered organ-ECIS model for investigating the real time effects of fibroblast growth factor-9 (FGF-9) on epithelial invagination in bioengineered ectodermal organs. We dissected epithelial and mesenchymal cells from stage E14.5 murine molar tooth germs and identified the real-time effects of FGF-9 on epithelial-mesenchymal interactions using this combined bioengineered organ-ECIS model.
  
  
  RESULTS
  Measurement of bioengineered ectodermal organ thickness showed that Fibroblast growth factor-9 (FGF-9) accelerates epithelial invagination in reaggregated mesenchymal cell layer within 3 days. Gene expression analysis revealed that FGF-9 stimulates and sustains early Ameloblastin and Amelogenin expression during odontogenesis.
  
  
  CONCLUSIONS
  This is the first real-time study to show that, FGF-9 plays an important role in epithelial invagination and initiates ectodermal organogenesis. Based on these findings, we suggest FGF-9 can be applied for further study in ectodermal organ regeneration, and we also proposed that the 'FGF-BMP balancing system' is important for manipulating the morphogenesis of ectodermal organs. The combined bioengineered organ-ECIS model is a promising method for ectodermal organ engineering and regeneration research.
authors.affiliation: Graduate Institute of Clinical Dentistry, School of Dentistry, National Taiwan University, Taipei, 10002, Taiwan. tyling@ntu.edu.tw.
authors.forename: Yun-Yuan
authors.initials: YY
authors.lastname: Tai
authors.forename: Rung-Shu
authors.initials: RS
authors.lastname: Chen
authors.forename: Yi
authors.initials: Y
authors.lastname: Lin
authors.forename: Thai-Yen
authors.initials: TY
authors.lastname: Ling
authors.forename: Min-Huey
authors.initials: MH
authors.lastname: Chen