We report the design and target validation of chimeric peptide EP45， a novel 45 amino acid monomeric dual agonist peptide that contains amino acid sequence motifs present within the blood glucose-lowering agent exendin-4 (Ex-4) and the appetite-suppressing agent PYY(3-36). In a new high-throughput FRET assay that provides real-time kinetic information concerning levels of cAMP in living cells， EP45 recapitulates the action of Ex-4 to stimulate cAMP production via the glucagon-like peptide-1 receptor (GLP-1R)， while also recapitulating the action of PYY(3-36) to inhibit cAMP production via the neuropeptide Y receptor (NPY2R). EP45 fails to activate glucagon or GIP receptors， whereas for cells that co-exp... More
We report the design and target validation of chimeric peptide EP45， a novel 45 amino acid monomeric dual agonist peptide that contains amino acid sequence motifs present within the blood glucose-lowering agent exendin-4 (Ex-4) and the appetite-suppressing agent PYY(3-36). In a new high-throughput FRET assay that provides real-time kinetic information concerning levels of cAMP in living cells， EP45 recapitulates the action of Ex-4 to stimulate cAMP production via the glucagon-like peptide-1 receptor (GLP-1R)， while also recapitulating the action of PYY(3-36) to inhibit cAMP production via the neuropeptide Y receptor (NPY2R). EP45 fails to activate glucagon or GIP receptors， whereas for cells that co-express NPY2R and adenosine A receptors， EP45 acts in an NPY2R-mediated manner to suppress stimulatory effects of adenosine on cAMP production. Collectively， such findings are remarkable in that they suggest a new strategy in which the co-existing metabolic disorders of type 2 diabetes and obesity will be treatable using a single peptide such as EP45 that lowers levels of blood glucose by virtue of its GLP-1R-mediated effect， while simultaneously suppressing appetite by virtue of its NPY2R-mediated effect.
