Synthesis and Structure - Activity Relationship of Mannose-Based Peptidomimetics Selectively Blocking Integrin α4β7 Binding to Mucosal Addressin Cell Adhesion Molecule-1

As part of our ongoing research in the development of α4β7 integrin antagonists, we are interested in peptidomimetics based on a rigid scaffold to allow the display of essential side chains in a suitable binding conformation while eliminating backbone amide bonds and therefore improving pharmacokinetic parameters of the drug. Except for a few examples, peptidomimetics scaffolds have only been moderately successful and often yield molecules that lack the potency of their peptide counterparts. However, we present herein a successful application of using a rigid scaffold. Starting from a mannopyranoside analogue previously discovered in our laboratory as an inhibitor of the α4β1/vascular cell adhesion molecule interaction, a biased library of functionalized carbohydrates was developed. One compound emerged from this library as an active and selective antagonist toward the α4β7/mucosal addressin cell adhesion molecule interaction. Conformational implications and the relevance of different pharmacophoric patterns will be discussed in order to explain the reverse selectivity and enhanced affinity.