Reduced enamel epithelium-derived cell niche in the junctional epithelium are maintained for a long time in mice
JOURNAL OF PERIODONTOLOGY
Authors: Soda, Miki; Saito, Kotaro; Ida-Yonemochi, Hiroko; Nakakura-Ohshima, Kuniko; Kenmotsu, Shinichi; Ohshima, Hayato
Abstract
Background Although numerous reports have demonstrated that the junctional epithelium (JE) is derived from the reduced enamel epithelium (REE), the fate of the REE-derived JE remains controversial. The present study elucidated the fate of the REE-derived JE and the cell dynamics of stem/progenitor cells in the JE following tooth eruption. Methods Mandibular first molar germs (embryonic days 15 to postnatal 1-day-old) were transplanted into the socket of 2-week-old mice after extraction of the upper first molars of B6 wild-type (WT) and green fluorescent protein (GFP) transgenic mice. After analysis by mu-CT, paraffin sections were processed for immunohistochemistry for Nestin, Ki67 and GFP. We also performed chasing analysis using BrdU-administered TetOP-H2B-GFP mice. Results Amelogenesis progressed normally in the cervical areas, and the structure of the JE was like that in normal tooth development. The JE was GFP-negative in transplantations using GFP transgenic mice as the host, and the oral epithelium (OE) showed a positive reaction. By contrast, the JE remained GFP-positive throughout the experimental period in transplantations using GFP transgenic mice as the donor. Chasing analysis revealed that H2B-GFP- and 5-Bromo-2 '-deoxyuridine (BrdU)-labeled cells in the basal side of the JE translocated to oral side of the JE as the chasing time increased. Some label-retaining cells remained at the supra-basal cell layer in the JE. Conclusion These results suggest that REE-derived cell niche in the JE is maintained for a long time following tooth eruption. Therefore, the JE may be available as the source of the odontogenic epithelium.
Isolation, culture, and induced multiple differentiation of Mongolian sheep adipose-derived mesenchymal stem cells
JOURNAL OF HISTOTECHNOLOGY
Authors: Zhao, Ruiyuan; Zhang, Qian; Liu, Kaidong; Yang, Peipei; Sun, Youde; Zhang, Yanru; Liu, Zongzheng
Abstract
Adipose-derived mesenchymal stem cells (ADSC) are adult pluripotent cells and important resources for cell-based therapies of animals. There are presently different kinds of somatic cells used as donor cells for clone successfully. However, studies on somatic cell nuclear transplantation (SCNT) using ADSC as donor cells from Mongolian sheep have not been reported up to now. This study tested optimal methods of isolating, purifying, and proliferating Mongolian sheep ADSC, and determine their multiple differentiation potentiality. Adipose tissue was removed from approximately 2-year-old sheep and ADSC were harvested by pancreatic enzyme decomposition and adherent culture method. The growth curves of the Passages 1, 5, and 10 cultures were plotted and the exponential growth was determined as a population doubling time of 34.1 h. The expression of OCT4, SOX2, and NANOG genes were increased at Passage 3 (P3) as seen by reverse transcription polymerase chain reaction (RT-PCR) analysis. ADSC from Passage 3 were induced to undergo neurogenesis and form cardiomyocytes and pancreatic islet-like cells under inductive environments in vitro. The differentiation properties of cardiomyocytes and islet-like cells were confirmed by histological staining with toluidine blue, periodic acid-Schiff, and dithizone. The expression of specific genes in these cells were also detected by RT-PCR. Our study results confirm that isolated cells were indeed ADSC and may provide valuable materials for somatic cell clone and transgenic research.