Intraluminal nutrients acutely strengthen rat intestinal MRP2 barrier function by a glucagon-like peptide-2-mediated mechanism

TOCCHETTI, GN; DOMINGUEZ CJ; ZECCHINATI, F; ARANA MR; RIGALLI, JP; RUIZ, ML; VILLANUEVA, SSM; MOTTINO, AD

ACTA PHYSIOLOGICA

WILEY-BLACKWELL PUBLISHING, INC

Lugar: Londres; Año: 2020

1748-1708

Aim: MRP2 is an intestinal ABC transporter that prevents the absorption of dietaryxenobiotics. The aims of this work were: i) to evaluate whether a short-term regulation ofintestinal MRP2 barrier function takes place in vivo after luminal incorporation of nutrientsand ii) to explore the underlying mechanism.Methods: MRP2 activity and localization were assessed in an in vivo rat model withpreserved irrigation and innervation. Nutrients were administered into distal jejunum.After 30-min treatments, MRP2 activity was assessed in proximal jejunum by quantifyingthe transport of the model substrate 2,4-dinitrophenyl-S-glutathione. MRP2 localizationwas determined by quantitative confocal microscopy. Participation of extracellularmediators was evaluated using selective inhibitors and by immunoneutralization.Intracellular pathways were explored in differentiated Caco-2 cells.Results: Oleic acid, administered intraluminally at dietary levels, acutely stimulated MRP2insertion into brush border membrane. This was associated with increased efflux activityand, consequently, enhanced barrier function. Immunoneutralization of the gut hormoneglucagon-like peptide-2 (GLP-2) prevented oleic acid effect on MRP2, demonstrating theparticipation of this trophic factor as a main mediator. Further experiments using selectiveinhibitors demonstrated that extracellular adenosine synthesis and its subsequent bindingto enterocytic A2B adenosine receptor (A2BAR) take place downstream GLP-2. Finally,studies in intestinal Caco-2 cells revealed the participation of A2BAR/cAMP/PKAintracellular pathway, ultimately leading to increased MRP2 localization in apicaldomains.Conclusion: These findings reveal an on-demand, acute regulation of MRP2-associatedbarrier function, constituting a novel physiological mechanism of protection against theabsorption of dietary xenobiotics in response to food intake.