Single‐Cell Level Identification Of Cephalic Epithelial Transcriptomic Signatures To Elucidate The Pathogenesis Of Cleft Lip/Palate

Abstract

Craniofacial development results from a tightly regulated choreography involving patterning, morphogenesis, and growth of multiple embryonic cell types. Clefts of the lip and/or palate are maiming disruptions of facial shape and represent the most common human craniofacial birth defect. During mammalian facial development, the maxillary prominence extends medially to contact the two nasal prominences (medial and lateral) at a three-way anatomical seam named lambdoidal junction (λ), wherein the three prominences coalesce. However, if there is an impaired fusion of the facial prominences orofacial clefting ensues. We have previously reported an essential role for the cephalic epithelium at the λ to enable normal fusion of the murine facial prominences. Using the mouse as a model, we have now generated single-cell RNAseq (scRNAseq) transcriptional profiles that identified the various murine epithelial subpopulations at the λ. I am currently studying the spatial and temporal characteristics of the epithelial subpopulations using microdissection the facial prominences prior/after the fusion process combined with bioimaging approaches. In parallel, we have also conducted all analyses also directly comparing wild-type and available genetic mutant mouse lines with orofacial clefting (PBX1/2 compound mutants). These analyses have identified key transcriptomic changes in mutant mice embryos providing a deeper understanding of the molecular mechanisms underlying the pathogenesis of orofacial clefting. Altogether, these approaches are helping to elucidate the spatiotemporal dynamics of the cell subpopulations comprising the λ epithelium in vivo, and the perturbed landscapes that cause disfiguring anomalies to the anatomical features of the mammalian face.