Profiling Gene Expression in The Epithelial and Mesenchymal Compartments of Developing Rodent Incisor at Single Cell Level

Objectives: Teeth are developed from the crosstalk of dental epithelial and mesenchymal tissues. Tooth development occurs in stages, and the process begins under the control of the oral epithelial tissue. The epithelial tissue of the dental placode instructs the development of the tooth by synthesizing signaling molecules including Shh, Wnt, Bmp and Fgf signals. These signaling pathways control the expression of specific transcription factors in the epithelium and mesenchyme. One of the earliest transcription factors to be expressed in the dental epithelium is Pitx2 (paired-like homeodomain transcription factor 2). We are interested in what initiates the expression of the transcription factor Pitx2 and the formation of the primary tooth germ.
Methods: To determine what gene regulatory network is required for tooth germ initiation, we profiled gene expression in the developing oral epithelium and mesenchyme during early stages of tooth development (E9.5, E10.5, E11.5 and E12.5). We used Laser Microdissection (LMD) to isolate epithelial and mesenchymal tissues from early embryonic stages of tooth development. After tissue isolation, we performed RNA-seq using the SMARTSEQ-2 protocol.
Results: We made libraries to profile the transcriptomes of the first brachial arch of E9.5 and E10.5 murine embryos and used LMD to isolate the epithelial and mesenchymal tissues to make libraries from E11.5 and E12.5 stages.
Conclusions: Profiling the transcriptomes of cells from the early stages of tooth development will help to uncover the initiation program underpinning tooth formation, which may be applied to the clinic in the future.