Single-Cell RNAseq Analysis of Murine Salivary Gland Development; Creating an Atlas of the Transcriptional Landscape

Understanding the dynamic transcriptional landscape throughout organ development will provide a template for regenerative therapies. Here, we generated a single-cell RNAseq atlas of murine submandibular glands identifying transcriptional profiles associated with cellular heterogeneity during landmark developmental events: endbud formation, branching morphogenesis, cytodifferentiation, maturation, and homeostasis. Trajectory inference analysis predicts unexpected lineage relationships during development, early specification of myoepithelial and basal duct cells, and suggests plasticity among acinar and duct populations. We identify transcription factors correlated with acinar differentiation including upregulation of Spdef, Etv1, and Xbp1, and loss of Ybx1, Eno1 and Atf3/4. Furthermore, we characterize two intercalated duct subsets defined by either Gfra3 and Kit, or Gstt1. This organ-specific atlas can be used to investigate specific cell functions and comparative studies predicting common mechanisms involved in development of branching organs.