title: Expression and nuclear translocation of glucocorticoid receptors in type 2 taste receptor cells.
abstract: Stress increases the secretion of glucocorticoids (GCs), potent steroid hormones that exert their effects on numerous target tissues by acting through glucocorticoid receptors (GRs). GC signaling significantly affects ingestive behavior and taste preferences in humans and rodent models, but far less is known about the hormonal modulation of the peripheral sensory system that detects and assesses nutrient content of foods. A previous study linked restraint stress in rats to diminished expression of mRNA for one subunit of the sweet taste receptor (Tas1r3) in taste tissue and reduced gustatory nerve excitation by sweet compounds. Using RT-PCR, we detected mRNAs for GRα in circumvallate taste papillae and in oral epithelium devoid of taste buds ("non-taste" tissue). Further, circumvallate tissue was significantly enriched in GR mRNA compared to non-taste tissue based on quantitative PCR. Histologically, GR protein was expressed in all taste bud populations examined (circumvallate, foliate and fungiform papillae). Using transgenic mice expressing green fluorescent protein, almost all (97%) Tas1r3-positive taste cells (sweet-/umami-sensitive) expressed GR compared to a significantly smaller percentage (89%) of TrpM5-positive taste cells (sweet-, umami- and bitter-sensitive). When mice (n=4) were restrain stressed, GR protein mobilized to the nucleus in Tas1r3-GFP taste cells (1.7-fold over controls). Our results suggest that GR can be activated in taste receptor cells and may play a role in specific taste qualities (e.g., sweet, umami, and bitter) to shape how the taste system responds to stress.
authors.affiliation: Monell Chemical Senses Center, 3500 Market St., Philadelphia, PA 19103, United States. Electronic address: rparker@monell.org.
authors.forename: M Rockwell
authors.initials: MR
authors.lastname: Parker
authors.affiliation: Monell Chemical Senses Center, 3500 Market St., Philadelphia, PA 19103, United States.
authors.forename: Dianna
authors.initials: D
authors.lastname: Feng
authors.affiliation: Monell Chemical Senses Center, 3500 Market St., Philadelphia, PA 19103, United States.
authors.forename: Brianna
authors.initials: B
authors.lastname: Chamuris
authors.affiliation: Monell Chemical Senses Center, 3500 Market St., Philadelphia, PA 19103, United States.
authors.forename: Robert F
authors.initials: RF
authors.lastname: Margolskee
mesh_terms: D000818:Animals; D005260:Female; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D008297:Male; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D021381:Protein Transport; D012333:RNA, Messenger / Q000378:metabolism; D043562:Receptors, G-Protein-Coupled / Q000235:genetics / Q000378:metabolism*; D011965:Receptors, Glucocorticoid / Q000235:genetics / Q000378:metabolism*; D012149:Restraint, Physical; D013315:Stress, Psychological / Q000378:metabolism; D050053:TRPM Cation Channels / Q000235:genetics / Q000378:metabolism*; D013650:Taste Buds / Q000378:metabolism*; D000098706:Taste Receptors, Type 2
chemical_list: D012333:RNA, Messenger; D043562:Receptors, G-Protein-Coupled; D011965:Receptors, Glucocorticoid; D050053:TRPM Cation Channels; C498617:Trpm5 protein, mouse; C411470:glucocorticoid receptor alpha; C431926:taste receptors, type 1; D000098706:Taste Receptors, Type 2; D049452:Green Fluorescent Proteins
keywords: Glucocorticoid receptor; Steroid hormone receptor; Stress; Tas1r3; Taste; Taste receptor cell