Spatiotemporal Expression Of Shh Signaling Pathway In Mandibular First Molar Tooth Germs Of Cav-1 Gene Knockout Mice

Caveolae is a surface-specific invaginated microdomain of the plasma membrane,consisting mainly of lipids and proteins.Caveolins,a surface marker protein of Caveolae,is an integral membrane protein that constitutes Caveolae.Caveolins has at least three subtypes,of which Cav-1 is Caveolae’s most important surface functional protein.Caveolae and Caveolins play a key role in a variety of cell biological functions.Recent studies have shown that Cav-1 is involved in tooth germ development.Shh is a highly conserved signaling pathway involved in the development of multiple organs.The Shh signal persists in the development of tooth germs,regulates the determination of odontogenic epithelial areas,the development of cusps and the formation of roots,and has an important role in determining the number of teeth.Studies have shown that Cav-1 helps Shh transport from the cell to the cell surface.Although both Cav-1 and Shh are involved in the development of tooth germs and the two are functionally related,it is not clear whether there is a regulatory relationship between Cav-1 and Shh signaling pathway during the development of tooth germs.ObjectiveTo compare the expression patterns of Shh signaling pathwayin the early development of mandibular first molar tooth germs in Cav-1 knockout mice and wild type mice.MethodCollect mandibular first molar tooth germs from Cav-1 knockout mice(KO)and homologous wild-type mice(WT)at embryonic development 13.5,14.5,15.5,16.5,17.5,and 18.5 days.Genotyping was identified by chain reaction(PCR)and immunohistochemical techniques.Immunohistochemical technique was used to detect the expression of Shh,Ptc-1,Ptc-2,Gli-1,Gli-2 in tooth germ tissues at different developmental stages and the data were statistically analized.ResultAt the E13.5,E14.5,E15.5,E16.5,E17.5 and E18.5,Shh,Ptc-1,Ptc-2,Gli-1,Gli-2 expressions were found both in the mandibular first molar tooth germ of WT and KO mice.Shh protein was positively expressed at the apical end of the bud tooth germ,and it was specifically expressed in the glaze area during the cap period,and in the ameloblast layer at the bell stage.Ptc-1 is expressed in epithelial buds and surrounding mesenchyme in E13.5,and in outer enamel epithelium,inner enamel epithelium,stellatereticulum,stratum intermedium,and dental papilla adjacent to inner enamel epithelium in E14.5-E17.5 days.In E18.5,Ptc-1 expression was still observed in the outer enamel epithelium,ameloblast,and the middle layer,but no Ptc-1 expression was detected in tooth papillae.The expression pattern of Ptc-2 in enamel was similar to that of Ptc-1,but no expression of Ptc-2 was detected in dental papilla.Both Gli-1 and Gli-2 were expressed in epithelium bud and surrounding mesenchyme at E13.5,and in enamel organ and dental papilla cells E14.5-E18.5.However,there was no significant difference in the expression patterns of Shh signaling pathway between of WT and KO mice.ConclusionThe expression patterns of Shh signaling pathway in the early development of mandibular first molar tooth germs were not significantly influenced by Cav-1gene deletion...