Transcriptomic profiling of dental epithelium and mesenchyme of the third deciduous molar of miniature pigs at embryonic day 50 and 60

Reciprocal epithelial–mesenchymal interactions play a fundamental role in ectodermal organogenesis. The tooth is a typical ectodermal organ for studying epithelial–mesenchymal interactions. The dental epithelium (DE) is considered to possess the original inductive odontogenic signals rather than the dental papilla (DP) derived from mesenchyme. At the bell stage, the outer layer of the DP that is adjacent to the DE starts to differentiate into odontoblasts first, implying potential induction by DE. Epithelial signals are requisite inducers for dental cusp formation and odontoblast differentiation. However, conflicting roles for these signals have been reported. Here, we separated DE and dental mesenchyme at early and late bell stage (embryonic day 50 and 60) of the third deciduous mandibular molars(DM3) in miniature pigs and mRNA sequencing was carried out. KEGG analysis and GO enrichment showed that PI3K/AKT was one of the most enriched pathways in DE from E50 to E60. We screened out 198 genes of secreted proteins that were expressed at higher levels in DE than in DP at E50. Function experiments supported the idea that PI3K/AKT signaling from DE to DP promotes odontoblast differentiation via COL4A6 secretion. Overall design: Transcriptomic profiles in E50 and E60 DM3 of miniature pigs using RNA sequencing (RNAseq)