Induction of intestinal multidrug resistance-associated protein 2 by glucagon-like Peptide 2 in the rat.
The effects of glucagon-like peptide 2 (GLP-2) on expression and activity of jejunal multidrug resistance-associated protein 2 (Mrp2; Abcc2) and glutathione transferase (GST) were evaluated. After GLP-2 treatment (12 μg/100 g b.wt. s.c., every 12 h, for 5 consecutive days), Mrp2 and the α class of GST proteins and their corresponding mRNAs were increased, suggesting a transcriptional regulation. Mrp2 was localized at the apical membrane of the enterocyte in control and GLP-2 groups, as detected by confocal immunofluorescence microscopy. As a functional assay, everted intestinal sacs were incubated in the presence of 1-chloro-2,4-dinitrobenzene in the mucosal compartment, and the glutathione-conjugated derivative, dinitrophenyl-S-glutathione (DNP-SG; model Mrp2 substrate), was detected in the same compartment by high-performance liquid chromatography. A significant increase in apical secretion of DNP-SG was detected in the GLP-2 group, consistent with simultaneous up-regulation of Mrp2 and GST. GLP-2 also promoted an increase in cAMP levels as detected in homogenates of intestinal mucosa. Treatment of rats with 2',3'-dideoxyadenosine (DDA), a specific inhibitor of adenylyl cyclase, abolished the increase in cAMP levels and Mrp2 protein promoted by GLP-2, suggesting cAMP as a mediator of Mrp2 modulation. Increased expression of Mrp2 and cAMP levels in response to GLP-2 occurred not only at the tip but also at the middle region of the villus, where constitutive expression of Mrp2 is normally low. In conclusion, our study suggests a role for GLP-2 in the prevention of cell toxicity of the intestinal mucosa by increasing Mrp2 chemical barrier function.
Villanueva
Silvina S M
SS
Instituto de Fisiología Experimental, Facultad de Ciencias Bioquímicas y Farmacéuticas, Suipacha 570, S2002LRL, Rosario, Argentina.
Arias
Agostina
A
Ruiz
María L
ML
Rigalli
Juan P
JP
Pellegrino
José M
JM
Vore
Mary
M
Catania
Viviana A
VA
Mottino
Aldo D
AD
D018528:ATP-Binding Cassette Transporters / Q000096:biosynthesis*; D000067956:Adenylyl Cyclase Inhibitors; D000818:Animals; D015153:Blotting, Western; D002851:Chromatography, High Pressure Liquid; D000242:Cyclic AMP / Q000378:metabolism; D016048:Dideoxyadenosine / Q000494:pharmacology; D020895:Enterocytes / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism / Q000473:pathology; D005260:Female; D005455:Fluorescent Antibody Technique; D053767:Glucagon-Like Peptide 2 / Q000494:pharmacology* / Q000502:physiology; D005982:Glutathione Transferase / Q000096:biosynthesis; D007413:Intestinal Mucosa / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism / Q000473:pathology; D007583:Jejunum / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism / Q000473:pathology; D007774:Lactation / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D020133:Reverse Transcriptase Polymerase Chain Reaction
D018528:ATP-Binding Cassette Transporters; C423013:Abcc2 protein, rat; D000067956:Adenylyl Cyclase Inhibitors; D053767:Glucagon-Like Peptide 2; D016048:Dideoxyadenosine; D000242:Cyclic AMP; D005982:Glutathione Transferase