Original Research ARTICLE
Expression of oncofetal antigen 5T4 in murine taste papillae
- 1Nara Medical University, Japan
- 2Kagawa University, Japan
- 3University of Manchester, United Kingdom
- 4Osaka University, Japan
BACKGROUND: Multicellular taste buds located within taste papillae on the tongue mediate taste sensation. In taste papillae, taste bud cells, such as taste receptor cells and taste precursor cells, and the surrounding lingual epithelium including epithelial progenitors (also called taste stem/progenitor cells) are maintained by continuous cell turnover throughout life. However, it remains unknown how the cells constituting taste buds proliferate and differentiate to maintain taste bud tissue. Based on in situ hybridization screening, we demonstrated that the oncofetal antigen 5T4 (also known as trophoblast glycoprotein: TPBG) gene is expressed in the adult mouse tongue.
RESULTS: In immunohistochemistry of coronal tongue sections, 5T4 protein was detected at a low level exclusively in the basal part of the lingual epithelium in developing and adult mice, and at a high level particularly in foliate papillae and circumvallate papillae (CVPs). Furthermore, immunohistochemistry of the basal part of CVPs indicated that the proliferation marker PCNA (proliferating cell nuclear antigen) co-localized with 5T4. 5T4 was strongly expressed in Krt5+ epithelial progenitors and Shh+ taste precursor cells, but weakly in mature taste receptor cells. The number of proliferating cells in the CVP was higher in 5T4-knockout mice than in wild-type mice, while neither cell differentiation nor the size of taste buds differed between these two groups of mice. Notably, X-ray irradiation enhanced cell proliferation more in 5T4-knockout mice than in wild-type mice.
CONCLUSIONS: Our results suggest that 5T4, expressed in epithelial progenitors (taste stem/progenitor cells) and taste precursor cells, may influence the maintenance of taste papillae under both normal and injury conditions.
Keywords: 5T4 oncofetal antigen, Circumvallate papilla, Taste bud, Epithelial progenitor, Taste precursor cell, taste receptor cell, Mouse
Received: 10 May 2019;
Accepted: 12 Jul 2019.
Edited by:Arturo Ortega, Center for Research and Advanced Studies (CINVESTAV), Mexico
Reviewed by:Linda A. Barlow, School of Medicine, University of Colorado Denver, United States
Peihua Jiang, Monell Chemical Senses Center, United States
Copyright: © 2019 Takahashi, Takahashi, Stern, Kirita and Tsuboi. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
Dr. Hiroo Takahashi, Kagawa University, Takamatsu, 760-8521, Kagawa, Japan, firstname.lastname@example.org
Prof. Akio Tsuboi, Osaka University, Suita, 565-0871, Ōsaka, Japan, email@example.com