Selective, tight-binding inhibitors of integrin alpha4beta1 that inhibit allergic airway responses

J Med Chem. 1999 Mar 11;42(5):920-34. doi: 10.1021/jm980673g.


Integrin alpha4beta1 mediates leukocyte recruitment, activation, mediator release, and apoptosis inhibition, and it plays a central role in inflammatory pathophysiology. High-affinity, selective inhibitors of alpha4beta1, based on the Leu-Asp-Val (LDV) sequence from the alternatively spliced connecting segment-1 (CS-1) peptide of cellular fibronectin, are described that employ a novel N-terminal peptide "cap" strategy. One inhibitor, BIO-1211, was approximately 10(6)-fold more potent than the starting peptide and exhibited tight-binding properties (koff = 1.4 x 10(-4) s-1, KD = 70 pM), a remarkable finding for a noncovalent, small-molecule inhibitor of a protein receptor. BIO-1211 was also 200-fold selective for the activated form of alpha4beta1, and it stimulated expression of ligand-induced epitopes on the integrin beta1 subunit, a property consistent with occupancy of the receptor's ligand-binding site. Pretreatment of allergic sheep with a 3-mg nebulized dose of BIO-1211 inhibited early and late airway responses following antigen challenge and prevented development of nonspecific airway hyperresponsiveness to carbachol. These results show that highly selective and potent small-molecule antagonists can be identified to integrins with primary specificity for peptide domains other than Arg-Gly-Asp (RGD); they confirm the generality of integrins as small molecule targets; and they validate alpha4beta1 as a therapeutic target for asthma.

MeSH terms

  • Animals
  • Anti-Allergic Agents / chemical synthesis*
  • Anti-Allergic Agents / chemistry
  • Anti-Allergic Agents / metabolism
  • Anti-Allergic Agents / pharmacology
  • Binding Sites
  • Bronchial Hyperreactivity / chemically induced
  • Bronchial Hyperreactivity / immunology
  • Bronchial Hyperreactivity / prevention & control*
  • Carbachol / toxicity
  • Cell Adhesion / drug effects
  • Cell Line
  • Drug Design
  • Epitopes
  • Fibronectins / chemistry
  • Fibronectins / physiology
  • Humans
  • Integrin alpha4beta1
  • Integrins / antagonists & inhibitors*
  • Integrins / metabolism
  • Jurkat Cells
  • Kinetics
  • Ligands
  • Oligopeptides / chemical synthesis*
  • Oligopeptides / chemistry
  • Oligopeptides / metabolism
  • Oligopeptides / pharmacology
  • Receptors, Lymphocyte Homing / antagonists & inhibitors*
  • Receptors, Lymphocyte Homing / metabolism
  • Sheep
  • Structure-Activity Relationship
  • Vascular Cell Adhesion Molecule-1 / physiology


  • Anti-Allergic Agents
  • Epitopes
  • Fibronectins
  • Integrin alpha4beta1
  • Integrins
  • Ligands
  • Oligopeptides
  • Receptors, Lymphocyte Homing
  • Vascular Cell Adhesion Molecule-1
  • leucyl-aspartyl-valine
  • BIO 1211
  • Carbachol