The intestinal glucose-apelin cycle controls carbohydrate absorption in mice.

Cédric Dray (1) , Yassine Sakar (2) , Claire Vinel (1) , Daniele Daviaud (1) , Bernard Masri (3) , Luc Garrigues (4) , Estelle Wanecq (1) , Sylvain Galvani (1) , Anne Negre-Salvayre (1) , Larry S. Barak (5) , Bernard Monsarrat (4) , Odile Burlet-Schiltz (4) , Philippe Valet (1) , Isabelle Castan-Laurell (1) , Robert Ducroc (2)

1 I2MC - Institut des Maladies Métaboliques et Cardiovasculaires
2 CRB3 - Centre de recherche biomédicale Bichat-Beaujon
3 CRCT - Centre de Recherches en Cancérologie de Toulouse
4 IPBS - Institut de pharmacologie et de biologie structurale
5 Department of Cell Biology

BACKGROUND & AIMS: Glucose is absorbed into intestine cells via the sodium glucose transporter 1 (SGLT-1) and glucose transporter 2 (GLUT2); various peptides and hormones control this process. Apelin is a peptide that regulates glucose homeostasis and is produced by proximal digestive cells; we studied whether glucose modulates apelin secretion by enterocytes and the effects of apelin on intestinal glucose absorption. METHODS: We characterized glucose-related luminal apelin secretion in vivo and ex vivo by mass spectroscopy and immunologic techniques. The effects of apelin on (14)C-labeled glucose transport were determined in jejunal loops and in mice following apelin gavage. We determined levels of GLUT2 and SGLT-1 proteins and phosphorylation of AMPKα2 by immunoblotting. The net effect of apelin on intestinal glucose transepithelial transport was determined in mice. RESULTS: Glucose stimulated luminal secretion of the pyroglutaminated apelin-13 isoform ([Pyr-1]-apelin-13) in the small intestine of mice. Apelin increased specific glucose flux through the gastric epithelial barrier in jejunal loops and in vivo following oral glucose administration. Conversely, pharmacologic apelin blockade in the intestine reduced the increased glycemia that occurs following oral glucose administration. Apelin activity was associated with phosphorylation of AMPKα2 and a rapid increase of the GLUT2/SGLT-1 protein ratio in the brush border membrane. CONCLUSIONS: Glucose amplifies its own transport from the intestinal lumen to the bloodstream by increasing luminal apelin secretion. In the lumen, active apelin regulates carbohydrate flux through enterocytes by promoting AMPKα2 phosphorylation and modifying the ratio of SGLT-1:GLUT2. The glucose-apelin cycle might be pharmacologically handled to regulate glucose absorption and assess better control of glucose homeostasis.

Mots clés: Calorie intake; mouse model; diabetes; adipokine; apelin

Domaines: Endocrinologie et métabolisme

Cédric Dray, Yassine Sakar, Claire Vinel, Daniele Daviaud, Bernard Masri, et al.. The intestinal glucose-apelin cycle controls carbohydrate absorption in mice.: Regulation and role of apelin in mouse intestine. Gastroenterology, 2013, 144 (4), pp.771-80. ⟨10.1053/j.gastro.2013.01.004⟩. ⟨inserm-00805173⟩