Distinct Cell Types With the Bitter Receptor Tas2r126 in Different Compartments of the Stomach

Abstract

Cells expressing bitter taste receptors (T2Rs or Tas2rs) in extraoral tissues are considered to be chemosensory cells mediating protective responses to potentially harmful or even antiinflammatory or antimicrobial compounds. In a previous study the activity of the Tas2R143/Tas2R135/Tas2r126 cluster promoter in the stomach was monitored using a Cre-reporter mouse line. Reporter gene expression and Tas2r126 mRNA were found in brush cells located at the distal wall of the gastric groove. In this study, we explored whether brush cells and epithelial cells of the stomach in fact contain the Tas2r126 receptor protein. Using immunohistochemistry, we demonstrate the presence of Tas2r126 immunoreactivity in different cell populations in the glandular stomach, in a subset of brush cells at the gastric groove and in unique glandular units as well as in certain enteroendocrine cells. In brush cells at the gastric groove, a strong immunofluorescence signal for the Tas2r126 receptor was observed at the most apical region of the cells, i.e., the microvillar tuft. In addition, we found a high density of Tas2r126-positive brush cells in the unique glandular units. These invaginations are located distally to the groove, open directly into the furrow and are enwrapped by smoothelin-immunoreactive muscles. In the corpus, Tas2r126 immunoreactivity was found in histamine-producing ECL cells and in ghrelin-producing X/A-like cells, the main enteroendcrine cells of this compartment. In the antrum, Tas2r126 labeling was observed in serotonin-storing EC cells and ghrelin cells, both representing only minor populations of enteroendocrine cells in this compartment. In conclusion, our data provide evidence for the presence of the Tas2r126 receptor protein in distinct cell types in the epithelium lining the mouse stomach which render the stomach responsive to agonists for bitter receptors.

The regulation of gastric ghrelin secretion

“…Increasing evidence is available on the role of bitter compounds in the modulation of ghrelin secretion. While detection of bitter compounds is accomplished by a large family of type 2 receptors (T2Rs), 105,106 existing reports show that T2R10, 102 T2R126 107 and α‐transducin, 108 a G‐protein involved in the detection of bitter compounds, 109 are co‐localized with ghrelin cells. Furthermore, studies using human gastric mucosal cultures from female and male obese subjects have shown that activation of a variety of bitter receptors, such as T2R10 (agonists: denatonium benzoate (DB), chloroquine and erythromycin A) and T2R5 (agonist: 1,10‐phenanthroline) stimulates AG secretion 102 .…”

Nutrient‐sensing components of the mouse stomach and the gastric ghrelin cell

“…Substantial knowledge is available on the nutrient‐sensing capabilities of the intestine, with most chemosensors presenting region‐specific expression patterns that are highly associated with distinctive functional characteristics of each intestinal region 4,8 . While little data are available on the nutrient‐sensing repertoire of the stomach, it is known that the expression of several bitter taste receptors (T2Rs), known to be highly co‐localized with ghrelin 30,31 and involved in the stimulation of ghrelin secretion, 31,32 varies in different compartments of the stomach 30,32 . Therefore, the first aim of this study was to investigate the expression of gastric nutrient chemosensors and their regional distribution within the mouse stomach.…”

Protective and Healing Effects of Ghrelin and Risk of Cancer in the Digestive System

“…Ghrelin is mainly synthesized in the gastric oxyntic mucosa, but its presence was also found in the oral cavity, small and large bowel, pancreas, thyroid, lung, testis, myocardium, kidney, brain cortex, brain stem, pituitary, hypothalamus, and immune cells [ 14 , 15 , 27 , 28 ]. In rats and dogs, ghrelin is produced in the stomach by the neuroendocrine X/A-like cells [ 29 , 30 ]. These cells are small and round.…”