RÉSUMÉ
Low-abundance regulatory peptides, including metabolically important gut hormones, have shown promising therapeutic potential. Here, we present a streamlined mass spectrometry-based platform for identifying and characterizing low-abundance regulatory peptides in humans. We demonstrate the clinical applicability of this platform by studying a hitherto neglected glucose- and appetite-regulating gut hormone, namely, oxyntomodulin. Our results show that the secretion of oxyntomodulin in patients with type 2 diabetes is significantly impaired, and that its level is increased by more than 10-fold after gastric bypass surgery. Furthermore, we report that oxyntomodulin is co-distributed and co-secreted with the insulin-stimulating and appetite-regulating gut hormone glucagon-like peptide-1 (GLP-1), is inactivated by the same protease (dipeptidyl peptidase-4) as GLP-1 and acts through its receptor. Thus, oxyntomodulin may participate with GLP-1 in the regulation of glucose metabolism and appetite in humans. In conclusion, this mass spectrometry-based platform is a powerful resource for identifying and characterizing metabolically active low-abundance peptides.
Sujet(s)
Diabète de type 2/sang , Dérivation gastrique , Spectrométrie de masse/méthodes , Oxyntomoduline/sang , Protéomique/méthodes , Animaux , Marqueurs biologiques/sang , Dipeptidyl peptidase 4/sang , Modèles animaux de maladie humaine , Glucagon-like peptide 1/sang , Humains , Souris , Oxyntomoduline/isolement et purificationRÉSUMÉ
An artificial gene encoding oxyntomodulin was obtained using chemical and enzymatic methods and cloned into Escherichia coli. A recombinant plasmid was constructed containing a hybrid oxyntomodulin gene and Ssp dnaB intein from Synechocystis sp. The expression of the resulting hybrid gene in E. coli, its properties, and the conditions of its autocatalytic cleavage to oxyntomodulin were studied.
