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

Abstract

The gastrointestinal (GI) tract relies on chemical and neural signals to control physiological processes, such as digestion, nutrient assimilation, and energy intake. 1 Nutrient chemosensors are essential for the assessment of the composition of luminal content within the GI tract. 2,3 They also play a crucial effector role in triggering gut hormone secretion responsible for the fine-tuning of GI function and feeding behavior. 4-6 An extensive array of nutrient chemosensors has been reported throughout the GI tract. 4,7,8 Sweet molecules are known to be sensed in the proximal intestine upon activation of the heterodimeric G

The Effect of High-Fat Diet-Induced Obesity on the Expression of Nutrient Chemosensors in the Mouse Stomach and the Gastric Ghrelin Cell

“…The expression of nutrient receptors in the mouse stomach is known to be regional, with a previous report showing that a large repertoire of gastric nutrient chemosensors are highly expressed in the antrum compared to the corpus [23]. The current study confirmed these findings, showing that most chemosensors presented higher mRNA expression in the antrum compared to the corpus, with the exception of CD36.…”

“…The current study confirmed these findings, showing that most chemosensors presented higher mRNA expression in the antrum compared to the corpus, with the exception of CD36. The higher expression of CD36 in the gastric corpus may be explained by the enrichment of this fatty acid transporter in corpus-predominant parietal [23,42] and ghrelin cells [23]. Furthermore, this report extends previous knowledge on the expression of gastric nutrient chemosensors, by defining changes in their mRNA levels in a well-established diet-induced obese mouse model [35,36] with elevated body weight, fat mass and blood glucose levels.…”

“…After processing, the tissue was stored at −80 • C until required for sectioning. The detailed protocol for gene expression experiments has been previously reported [23]. In brief, a PureLink RNA Mini kit (Thermo Fisher Scientific, Adelaide, SA, Australia) was used to extract total RNA from the corpus and antrum mucosa, according to the manufacturer's instructions.…”

“…Relative mRNA expression was calculated using the 2 −∆CT method [37]. The experimental conditions for the immunohistochemistry were adapted from a previous report [23]. Stomach cryosections (10 µm) were air-dried prior to three 5 min rinses in PBS (pH 7.4) containing 0.2% Triton X-100 (PBS-TX; Sigma-Aldrich, Castle Hill, NSW, Australia).…”

“…Furthermore, there is emerging evidence to indicate that gastric nutrient-sensing is an important contributing factor in the control of ghrelin secretion. Previous studies have demonstrated that numerous nutrient chemosensors are highly expressed in gastric ghrelin cells, including receptors for bitter (taste receptors type 2; T2Rs [20,21]), sweet and umami compounds (taste receptor 1 member 3; T1R3 [22,23]), short-chain fatty acids (free fatty acid receptor (FFAR) 2 [24]), long-chain fatty acids (FFAR4 [23,24] and cluster of differentiation (CD) 36 [23]), and protein digestion products (calcium-sensing receptor (CaSR [24,25]) and G-protein-coupled receptor 93 (GPR93 [23]). Many of these nutrient chemosensors were found to be involved in ghrelin secretion.…”