A New Class of Highly Potent and Selective Endomorphin-1 Analogues Containing α-Methylene-β-aminopropanoic Acids (Map)
作者:Yuan Wang、Yanhong Xing、Xin Liu、Hong Ji、Ming Kai、Zongyao Chen、Jing Yu、Depeng Zhao、Hui Ren、Rui Wang
DOI:10.1021/jm300664y
日期:2012.7.12
A new class of endomorphin-1 (EM-1) analogues were synthesized by introduction of novel unnatural alpha-methylene-beta-amino acids (Map) at position 3 or/and position 4. Their binding and functional activity, metabolic stability, and antinociceptive activity were determined and compared. Most of these analogues showed high affinities for the mu-opioid receptor and an increased stability in mouse brain homogenates compared with EM-1. Examination of cAMP accumulation and ERK1/2 phosphorylation in HEK293 cells confirmed the agonist properties of these analogues. Among these new analogues, H-Tyr-Pro-Trp-(2-furyl)Map-NH2 (analogue 12) exhibited the highest binding potency (K-i(mu) = 0.221 nM) and efficacy (EC50 = 0.0334 nM, E-max = 97.14%). This analogue also displayed enhanced antinociceptive activity in vivo in comparison to EM-1. Molecular modeling approaches were then carried out to demonstrate the interaction pattern of these analogues with the opioid receptors. We found that, compared to EM-1, the incorporation of our synthesized Map at position 4 would bring the analogue to a closer binding mode with the mu-opioid receptor.