Newly established cell lines from mouse oral epithelium regenerate teeth when combined with dental mesenchyme

The present study attempted to examine whether clonal cell lines of the oral epithelium can differentiate into ameloblasts and regenerate tooth when combined with dental germ mesenchyme. Clonal cell lines with a distinct morphology were established from the oral epithelium of p53-deficient fetal mice at embryonic day 18 (E18). The strain of mouse is shown to be a useful source for establishing clonal and immortalized cell lines from various tissues and at various stages of development. Tooth morphogenesis is almost completed and the oral epithelium is segregated from the dental epithelium at E18. In RT-PCR analysis of cell lines, mucosal epithelial markers (cytokeratin 14) were detected, but ameloblast markers such as amelogenin and ameloblastin were not detected when cells were cultured on plastic dish. They formed stratified epithelia and expressed a specific differentiation marker (CK13) in the upper layer when cultured on feeder layer or on collagen gel for 1–3 wk, demonstrating that they are of oral mucosa origin. Next, bioengineered tooth germs were prepared with cell lines and fetal molar mesenchymal tissues and implanted under kidney capsule for 2–3 wk. Five among six cell lines regenerated calcified structures as seen in natural tooth. Our results indicate that some oral epithelial cells at E18 possess the capability to differentiate into ameloblasts. Furthermore, cell lines established in the present study are useful models to study processes in tooth organogenesis and tooth regeneration

Identification of a developmentally regulated gene in the mouse central nervous system which encodes a novel proline rich protein

A full length cDNA whose corresponding mRNA is down-regulated during the mouse embryonic brain development was isolated. The cDNA contains a single long open reading frame which could encode a protein with relative molecular mass of 41 kDa. The predicted gene product contains long stretches of prolines towards the NH2-terminus, followed by a leucine/proline rich region. The cDNA probe detected a number of mRNA species in Northern blot analysis. The reverse transcriptase-polymerase chain reaction analysis of mRNA from adult mouse tissues indicated that heart and testis expressed this gene (named NDPP-1) at relatively high levels, while lower levels of mRNA were detected in a number of other tissues. Expression of NDPP-1 was also detected in embryonic carcinoma and pheochromocytoma cell lines, but not in fibroblasts. The cDNA hybridized to genomic DNA from several vertebrates species in Southern blot analysis indicating interspecies conservation of this gene. The interesting pattern of expression of the NDPP-1 gene during mouse brain development and the structure of its putative protein product indicate that this gene may play an important biological role in the development of mouse central nervous system.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/29785/1/0000124.pd

Successful Reconstruction of Tooth Germ with Cell Lines Requires Coordinated Gene Expressions from the Initiation Stage

Tooth morphogenesis is carried out by a series of reciprocal interactions between the epithelium and mesenchyme in embryonic germs. Previously clonal dental epithelial cell (epithelium of molar tooth germ (emtg)) lines were established from an embryonic germ. They were odontogenic when combined with a dental mesenchymal tissue, although the odontogenesis was quantitatively imperfect. To improve the microenvironment in the germs, freshly isolated dental epithelial cells were mixed with cells of lines, and germs were reconstructed in various combinations. The results demonstrated that successful tooth construction depends on the mixing ratio, the age of dental epithelial cells and the combination with cell lines. Analyses of gene expression in these germs suggest that some signal(s) from dental epithelial cells makes emtg cells competent to communicate with mesenchymal cells and the epithelial and mesenchymal compartments are able to progress  odontogenesis from the initiation stage

Design of a Sensitive Extracellular Vesicle Detection Method Utilizing a Surface-Functionalized Power-Free Microchip

Extracellular vesicles (EVs), which are small membrane vesicles secreted from cells into bodily fluids, are promising candidates as biomarkers for various diseases. We propose a simple, highly sensitive method for detecting EVs using a microchip. The limit of detection (LOD) for EVs was improved 29-fold by changing the microchannel structure of the microchip and by optimizing the EV detection protocols. The height of the microchannel was changed from 25 to 8 µm only at the detection region, and the time for EV capture was extended from 5 to 10 min. The LOD was 6.3 × 1010 particles/mL, which is lower than the concentration of EVs in the blood. The detection time was 19 min, and the volume of EV solution used was 2.0 µL. These results indicate that an efficient supply of EVs to the detection region is effective in improving the sensitivity of EV detection. The proposed EV detection method is expected to contribute to the establishment of EV-based cancer point-of-care testing