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Abstract
Taste buds are taste sensory organs that require continuous cell renewal to maintain their homeostasis. Thus, properly functioning progenitors in the surrounding tissue compartments are necessary throughout the developmental course of taste buds. Lingual taste bud resides in taste papillae in oral tongue, in which taste buds are surrounded by lingual epithelium, underlying connective tissue core, and minor salivary gland, i.e., von Ebner’s gland. In the past decades, taste bud-surrounding basal epithelium has been considered as the sole progenitor source for taste buds. However, our recent findings revealed that Sox10-expressing cells, i.e., neural crest, and/or cells in tissue compartments under lingual epithelium, i.e., connective tissue core of taste papillae and/or von Ebner’s gland, serve as taste bud cell progenitors that differentiate to mainly type III taste cells during taste bud maturation and maintenance in postnatal mice. Follow-up studies mapping the lineage of Sox10-expressing neural crest cells in three model species indicated that neural crest cells and their derivatives in the tongue connective tissue do not give rise to taste buds, leaving non-neural crest-derived cells in connective tissue and von Ebner’s glands to be determined. To investigate the potential contribution of those progenitor candidates to taste buds, multiple inducible Cre mouse models were used to map the lineage of cells in connective tissue (including stromal cells and Schwann cells) and cells in von Ebner’s glands. The observations from those studies indicated that von Ebner’s glands, but not connective tissue cores of taste papillae, most likely host the progenitors for taste buds during postanal maturation and maintenance. Future studies will focus on collecting solid evidence to verify von Ebner’s glands’ contribution to taste buds. At last, a protocol for cell dissociation from tongue epithelium and mesenchyme/connective tissue was developed for cell preparation for single cell RNA-Sequencing and 3D organoid cultures that will facilitate our studies to better understand the origin of taste bud cells.