Spatiotemporal Expression Of Caveolin-1, CD147and MMP-2during The Mouse Molar Tooth Germ Development

The tooth is an organ that develops as a result of reciprocal interactions betweenthe dental epithelium and the neural crest-derived mesenchyme. The signals networkcomposed of the cascade reactions of many signaling molecules, are involved inregulating tooth morphogenesis, cell differentiation and dental hard tissues formation.Basement membrane lies between dental epithelial and embryonic mesenchyme, itsdegradation in time makes the two tissues touch each other to send signals, thusinducing tooth development. Caveolae are morphologically identifiable as smallomega-shaped plasma membrane invaginations, providing the platform of cellsignaling transduction; Caveolin-1, the biochemical maker protein, is in the center ofcell signaling, can collect many signaling molecules to Caveolae and regulate theiractivity. Matrix metalloproteinases (MMP)-2may take part in the reconstruction andfinal degradation of the basement membrane locating between enamel organ anddental papilla, and has special induction in cell migration and growth differentiation.In vitro studies have confirmed that Caveolin-1as a negative regulator, interactswith extracellular matrix metalloproteinase inducer(EMMPRIN/CD147), can impedethe CD147glycosylation, self-oligomerization, and regulate CD147-mediated signaltransduction, and then affect the activity of matrix metalloproteinases.ObjectiveTo exam the expression patterns of Caveolin-1, CD147and MMP-2duringdifferent stages of tooth germ development and figure out their relationships duringmouse tooth germ development.MethodCollect the mouse molar tooth germs: embryonic (E)11.5，13.5，14.5，16.5，18.5days and postnatal2days(PN2). Immunohistochemistry was used to examine theexpression patterns of Caveolin-1, CD147and MMP-2in above tooth germ tissues.Result At the lamina stage (E11.5), Caveolin-1, CD147and MMP-2were all negativelyexpressed in the dental epithelium or mesenchyme.At the bud stage (E13.5), Caveolin-1was expressed in the dental epitheliumobviously. CD147was weakly expressed in the mesenchyme. The expression ofMMP-2was not detected.At the cap stage (E14.5), Caveolin-1and CD147were both strongly expressed inthe enamel organ. Caveolin-1was highly expressed in the lingual area of enamelorgan, while CD147in the buccal area. The expression of MMP-2was not detected.At the early bell stage (E16.5), Caveolin-1was strongly expressed in theocclusal side area of inner enamel epithelium. CD147was expressed in the enamelorgan. MMP-2started to expressed in the inner enamel epithelium, especially in thebasement membrane.At the later bell stage (E18.5), Caveolin-1and CD147were both expressed inthe inner enamel epithelium, but the staining of Caveolin-1was weaker than CD147.MMP-2was weakly expressed in the inner enamel epithelium, outer enamelepithelium and dental papilla.At the postnatal2days (PN2), Caveolin-1was strongly expressed in theameloblast and cervical loop area. CD147was strongly expressed in the ameloblastand odontoblast, but weakly in the cervical loop area. MMP-2was mainly expressedin the ameloblast, particularly in the adjacent area of ameloblast and stratumintermedium.Conclusion1. Caveolin-1, CD147and MMP-2might participate in mouse tooth germdevelopment.2. From the bud stage to early bell stage of mouse tooth germ development, thestaining of Caveolin-1and CD147exhibited antagonistic, suggesting that Caveolin-1might take part in the regulation of CD147expression.