Comparative secretome analysis of rat stomach under different nutritional status

The fact that gastric surgery is at the moment the most effective treatment to fight against obesity highlights the relevance of gastric derived proteins as potential targets to treat this pathology. Taking advantage of a previously established gastric explant model for endocrine studies, the proteomic analysis of gastric secretome was performed. To validate this gastric explant system for proteomic analysis, the identification of ghrelin, a classical gastric derived peptide, was performed by MS. In addition, the differential analysis of gastric secretomes under differential nutritional status (control feeding vs fasting vs re-feeding) was performed. The MS identified proteins are showed in the present manuscript. The data supplied in this article is related to the research article entitled “Comparative secretome analysis of rat stomach under different nutritional status” [1]

The Gastric CB1 Receptor Modulates Ghrelin Production through the mTOR Pathway to Regulate Food Intake

<div><p>Over the years, the knowledge regarding the relevance of the cannabinoid system to the regulation of metabolism has grown steadily. A central interaction between the cannabinoid system and ghrelin has been suggested to regulate food intake. Although the stomach is the main source of ghrelin and CB1 receptor expression in the stomach has been described, little information is available regarding the possible interaction between the gastric cannabinoid and ghrelin systems in the integrated control of energy homeostasis. The main objective of the present work was to assess the functional interaction between these two systems in terms of food intake using a combination of in vivo and in vitro approaches. The present work demonstrates that the peripheral blockade of the CB1 receptor by rimonabant treatment decreased food intake but only in food-deprived animals. This anorexigenic effect is likely a consequence of decreases in gastric ghrelin secretion induced by the activation of the mTOR/S6K1 intracellular pathway in the stomach following treatment with rimonabant. In support of this supposition, animals in which the mTOR/S6K1 intracellular pathway was blocked by chronic rapamycin treatment, rimonabant had no effect on ghrelin secretion. Vagal communication may also be involved because rimonabant treatment was no longer effective when administered to animals that had undergone surgical vagotomy. In conclusion, to the best of our knowledge, the present work is the first to describe a CB1 receptor-mediated mechanism that influences gastric ghrelin secretion and food intake through the mTOR pathway.</p></div

Primers for the real time qPCR analyses.

<p>Primers for the real time qPCR analyses.</p

Measures of pmTOR/mTOR levels in gastric mucosa and representative Western blots from animals in the fasting state treated with ip rimonabant and/or ip rapamycin chronically for 1 week (A).

<p>Phospho-S6K1/S6K1 in gastric mucosae from animals in the fasting state treated with rimonabant ip and/or rapamycin ip chronically for 1 week (B). The results are expressed as percentages over control (phospho-S6K1/S6K1). *p<0.05, vs control; ^#p<0.05 vs rimonabant. C: control, R: rimonabant, Ra: rapamycin; Ra+R: rapamycin+rimonabant.</p

Food Intake measures in rats after icv treatment with ghrelin/vehicle (6 µg/rat) and ip treatment with rimonabant (3 mg/kg ip)/vehicle under different nutritional statuses: A) <i>Ad libitum</i> fed, B) nocturnal fasting, c) animals subjected to overnight fasting and previously subjected to surgical vagotomy.

<p>*vs control, ^#vs. rimonabant+ghrelin.</p

mRNA expression levels measured by real-time PCR for ghrelin in <i>ad libitum</i> fed animals (A) or 36-hour fasted animals (B).

<p>Ghrelin protein levels and representative Western blot from the mucosa from <i>ad libitum</i> fed animals (C) or 36-hours fasted animals (D). Animals that received different in vivo treatments (control/rimonabant) and surgical procedures (vagotomy/sham-operated). C: control, R: rimonabant, V: vagotomy; V+R: vagotomy+rimonabant. CB1 receptor mRNA levels in the gastric mucosae of <i>ad libitum</i> fed animals (E) or 36-hour fasted animals (F) and animals that received different in vivo treatments (control/rimonabant) and surgical procedures (vagotomy/sham operated). *vs control.</p

Gastric ghrelin secretion from tissue explants (A) and plasma ghrelin levels (B) obtained from 36-hour fasted animals that received in vivo treatment with AM281 (3 mg/Kg ip).

<p>**p<0.01.</p

Gastric ghrelin secretion (A).

<p>Ghrelin mRNA levels measured by real-time PCR in the gastric mucosae (B) and plasma ghrelin levels (C) from animals in fasting states treated with ip rimonabant and/or ip rapamycin chronically for 1 week.</p

Gastric ghrelin secretion from tissue explants obtained from <i>ad libitum</i> fed animals (A) or 36-hour fasted animals (B) and plasma ghrelin levels from <i>ad libitum</i> fed animals (C) or 36-hour fasted animals (D) under different in vivo treatments (control/rimonabant), and surgical procedures (vagotomy/sham operated).

<p>Gastric ghrelin secretion from tissue explants from <i>ad libitum</i> fed animals (E) or 36-hour fasted animals (F) under different in vitro treatments (control/rimonabant) and surgical procedures (vagotomy/sham operated). *vs control.</p