Segregated Expression of ENaC Subunits in Taste Cells

TY - JOUR

T1 - Segregated Expression of ENaC Subunits in Taste Cells

AU - Lossow, Kristina

AU - Hermans-Borgmeyer, Irm

AU - Meyerhof, Wolfgang

AU - Behrens, Maik

N1 - © The Author(s) 2020. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

PY - 2020/5/21

Y1 - 2020/5/21

N2 - Salt taste is one of the 5 basic taste qualities. Depending on the concentration, table salt is perceived either as appetitive or aversive, suggesting the contribution of several mechanisms to salt taste, distinguishable by their sensitivity to the epithelial sodium channel (ENaC) blocker amiloride. A taste-specific knockout of the α-subunit of the ENaC revealed the relevance of this polypeptide for low-salt transduction, whereas the response to other taste qualities remained normal. The fully functional ENaC is composed of α-, β-, and γ-subunits. In taste tissue, however, the precise constitution of the channel and the cell population responsible for detecting table salt remain uncertain. In order to examine the cells and subunits building the ENaC, we generated mice carrying modified alleles allowing the synthesis of green and red fluorescent proteins in cells expressing the α- and β-subunit, respectively. Fluorescence signals were detected in all types of taste papillae and in taste buds of the soft palate and naso-incisor duct. However, the lingual expression patterns of the reporters differed depending on tongue topography. Additionally, immunohistochemistry for the γ-subunit of the ENaC revealed a lack of overlap between all potential subunits. The data suggest that amiloride-sensitive recognition of table salt is unlikely to depend on the classical ENaCs formed by α-, β-, and γ-subunits and ask for a careful investigation of the channel composition.

AB - Salt taste is one of the 5 basic taste qualities. Depending on the concentration, table salt is perceived either as appetitive or aversive, suggesting the contribution of several mechanisms to salt taste, distinguishable by their sensitivity to the epithelial sodium channel (ENaC) blocker amiloride. A taste-specific knockout of the α-subunit of the ENaC revealed the relevance of this polypeptide for low-salt transduction, whereas the response to other taste qualities remained normal. The fully functional ENaC is composed of α-, β-, and γ-subunits. In taste tissue, however, the precise constitution of the channel and the cell population responsible for detecting table salt remain uncertain. In order to examine the cells and subunits building the ENaC, we generated mice carrying modified alleles allowing the synthesis of green and red fluorescent proteins in cells expressing the α- and β-subunit, respectively. Fluorescence signals were detected in all types of taste papillae and in taste buds of the soft palate and naso-incisor duct. However, the lingual expression patterns of the reporters differed depending on tongue topography. Additionally, immunohistochemistry for the γ-subunit of the ENaC revealed a lack of overlap between all potential subunits. The data suggest that amiloride-sensitive recognition of table salt is unlikely to depend on the classical ENaCs formed by α-, β-, and γ-subunits and ask for a careful investigation of the channel composition.

KW - Amiloride/metabolism

KW - Animals

KW - Cloning, Molecular

KW - Epithelial Sodium Channels/metabolism

KW - Gene Knock-In Techniques

KW - Genotyping Techniques

KW - Humans

KW - Kidney

KW - Luminescent Proteins/genetics

KW - Mice

KW - Mice, Inbred C57BL

KW - Models, Animal

KW - Protein Conformation

KW - Taste

KW - Taste Buds/cytology

KW - Taste Perception

KW - Tissue Distribution

U2 - 10.1093/chemse/bjaa004

DO - 10.1093/chemse/bjaa004

M3 - SCORING: Journal article

C2 - 32006019

VL - 45

SP - 235

EP - 248

JO - CHEM SENSES

JF - CHEM SENSES

SN - 0379-864X

IS - 4

ER -