We have optimized 1 (P5U) and urantide, two important ligands at the h-UT receptor, designing several analogues by the exchange of the Tyr(9) residue with different unnatural aromatic amino acids. This study allowed us to discover novel ligands with improved activity. In particular, the replacement of the Tyr(9) residue by (pCN)Phe or (pNO(2))Phe within the urantide sequence led to compounds 13 (UPG-83) and 15 (UPG-95), respectively, which showed pure antagonist activity toward UT receptor in a rat aorta bioassay. More interestingly, the replacement of the Tyr(9) in 1 sequence with the Btz or the (3,4-Cl)Phe residues led to superagonists 6 (UPG-100) and 10 (UPG-92) with pEC(50) values at least 1.4 log higher than that of 1, being the most potent UT agonists discovered to date. Compounds 10 and 13 showed also a good stability in a serum proteolytic assay. These ligands represent new useful tools to further characterize the urotensinergic system in human physiopathology.
Lead Optimization of P5U and Urantide: Discovery of Novel Potent Ligands at the Urotensin-II Receptor
CAMPIGLIA, Pietro;
2014-01-01
Abstract
We have optimized 1 (P5U) and urantide, two important ligands at the h-UT receptor, designing several analogues by the exchange of the Tyr(9) residue with different unnatural aromatic amino acids. This study allowed us to discover novel ligands with improved activity. In particular, the replacement of the Tyr(9) residue by (pCN)Phe or (pNO(2))Phe within the urantide sequence led to compounds 13 (UPG-83) and 15 (UPG-95), respectively, which showed pure antagonist activity toward UT receptor in a rat aorta bioassay. More interestingly, the replacement of the Tyr(9) in 1 sequence with the Btz or the (3,4-Cl)Phe residues led to superagonists 6 (UPG-100) and 10 (UPG-92) with pEC(50) values at least 1.4 log higher than that of 1, being the most potent UT agonists discovered to date. Compounds 10 and 13 showed also a good stability in a serum proteolytic assay. These ligands represent new useful tools to further characterize the urotensinergic system in human physiopathology.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
