In Vitro Functional Characterization of Type-I Taste Bud Cells as Monocytes/Macrophages-like Which Secrete Proinflammatory Cytokines

Exploring the Role of Ccn3 in Type III Cell of Mice Taste Buds

Different taste cells express unique cell-type markers, enabling researchers to distinguish them and study their functional differentiation. Using single-cell RNA-Seq of taste cells in mouse fungiform papillae, we found that Cellular Communication Network Factor 3 (Ccn3) was highly expressed in Type III taste cells but not in Type II taste cells. Ccn3 is a protein-coding gene involved in various biological processes, such as cell proliferation, angiogenesis, tumorigenesis, and wound healing. Therefore, in this study, we aimed to explore the expression and function of Ccn3 in mouse taste bud cells. Using reverse transcription polymerase chain reaction (RT-PCR), in situ hybridization, and immunohistochemistry (IHC), we confirmed that Ccn3 was predominantly expressed in Type III taste cells. Through IHC, quantitative real-time RT-PCR, gustatory nerve recordings, and short-term lick tests, we observed that Ccn3 knockout (Ccn3-KO) mice did not exhibit any significant differences in the expression of taste cell markers and taste responses compared to wild-type controls. To explore the function of Ccn3 in taste cells, bioinformatics analyses were conducted and predicted possible roles of Ccn3 in tissue regeneration, perception of pain, protein secretion, and immune response. Among them, an immune function is the most plausible based on our experimental results. In summary, our study indicates that although Ccn3 is strongly expressed in Type III taste cells, its knockout did not influence the basic taste response, but bioinformatics provided valuable insights into the possible role of Ccn3 in taste buds and shed light on future research directions.

Morphogenesis of fungiform papillae in developing miniature pigs

Objective

Fungiform papillae contain taste buds and play a critical role in mastication and the gustatory system. In this study, we report a series of sequential observations of organogenesis of fungiform papillae in miniature pigs, as well as changes in the expression of BMP2, BMP4, Wnt5a, Sox2, and Notch1 signaling pathway components.

Design

In this study, we investigated the spatiotemporal expression patterns of BMP, Wnt, Sox2 and Notch in the fungiform papillae of miniature pigs at the bud stage (E40), cap stage (E50) and bell stage (E60). Pregnant miniature pigs were obtained, and the samples were processed for histological staining. Immunohistochemistry and real-time PCR were used to detect the mRNA and protein expression levels of BMP2, BMP4, Wnt5a, Sox2, and Notch1.

Results

At E40, fungiform papillae were present on the anterior two-thirds of the tongue in a specific array and pattern. The fungiform papillae were enlarged and basically developed at E50 and were largest at the earlier stage (E60). Most of the BMP2 was concentrated in the epithelial layer and the connective tissue core of the fungal papilloma and gradually accumulated from E40-E60. BMP-4 was weakly expressed in the fungiform papillae epithelia, but BMP-4-positive cells were also observed in the developing tongue muscle at E50 and E60. Wnt5a-positive cells were observed in the fungiform papillae epithelia and developing tongue muscle at all three time points. Sox2-positive cells were observed only in fungiform papillae epithelial cells, and Notch1-positive cells could not be detected.

Conclusions

This study provides primary data regarding the morphogenesis and expression of developmental signals in the fungiform papillae of miniature pigs, establishing a foundation for further research in both this model and humans.