Identification of novel function of vimentin for quality standard for regenerated pulp tissue.
ABSTRACT Pulp stem/progenitor cells have been successfully transplanted after pulpectomy in dogs and have led to pulp regeneration. The regenerated pulp tissue was investigated by the qualitative and quantitative protein expression patterns in comparison with those of normal pulp. There is an unmet need for a quality standard for regenerated pulp tissue.
Three distinct human CD105(+) stem/progenitor cells from dental pulp, bone marrow, and amnion were compared by 2-dimensional electrophoresis and the differential proteomic expression profiles. The protein identified with high confidence in pulp CD105(+) cells was examined by immunohistochemistry and real-time reverse-transcription polymerase chain reaction in regenerated pulp tissue compared with normal pulp. Its migration effect was further examined in pulp CD105(+) cells using small interfering RNA techniques to knock down the protein.
Nine protein spots were detected solely in pulp CD105(+) cells; one of these was identified as vimentin. The expression of vimentin messenger RNA was highest in pulp tissue among a variety of human tissues and higher in pulp CD105(+) cells compared with other CD105(+) cells and unfractionated total pulp cells. Pulp cells and endothelial cells were positively stained with vimentin in regenerated pulp tissue similarly as those in normal pulp tissue. The expression of vimentin in regenerated pulp was similar to normal pulp. RNA interference knock down of vimentin expression in pulp CD105(+) cells significantly reduced the migration activity.
The highest expression of vimentin in pulp tissue among other tissues and its migration effect in pulp stem cells suggest that it is a quality standard for pulp regeneration and pulp cell function.