A cyclic hexapeptide is a potent antagonist of alpha 4 integrins.
The alpha 4 integrins mediate leukocyte adhesion to specific counter-receptors, including vascular cell adhesion molecule-1 (VCAM-1), the fibronectin splice variant containing connecting segment 1 (CS1), and mucosal addressin cell adhesion molecule-1. A series of cyclized peptides based on the LDV sequence of CS1 were synthesized and assayed for inhibition of alpha 4 integrin binding. The most potent peptide, C*WLDVC* (where * indicates disulfide-linked residues), inhibited alpha 4 beta 1-dependent binding of lymphocytes to VCAM-1 and CS1 with half-maximal inhibition achieved at 1 to 3 microM of peptide. The peptide proved more potent when the lymphocytes were activated with 1 mM MnCl2; half-maximal inhibition was reached at 0.4 and 0.05 microM for VCAM-1 and CS1, respectively. This represents a 100- to 800-fold increase in potency over a linear CS1 peptide in these same assays. C*WLDVC* also inhibited alpha 4 beta 7-dependent lymphocyte binding to the ligands mucosal addressin cell adhesion molecule-1, VCAM-1 and CS1. Immunoprecipitation of radiolabeled integrin indicated that the peptide could bind alpha 4 beta 1 and alpha 4 beta 7 directly and elute alpha 4 beta 1 from a CS1-conjugated agarose resin. The peptide showed selectivity for alpha 4 integrins in that it effectively inhibited alpha 4 beta 1-dependent, but not alpha 5 beta 1-dependent, binding of cells to intact fibronectin. Due to its small size and potency, C*WLDVC* may serve as a useful tool for the study of alpha 4 integrin biology and the development of small molecule therapeutics.
Vanderslice
P
P
Department of Immunology, Texas Biotechnology Corp., Houston 77030, USA.
Ren
K
K
Revelle
J K
JK
Kim
D C
DC
Scott
D
D
Bjercke
R J
RJ
Yeh
E T
ET
Beck
P J
PJ
Kogan
T P
TP
D000595:Amino Acid Sequence; D000818:Animals; D001667:Binding, Competitive / Q000276:immunology; D002448:Cell Adhesion / Q000187:drug effects / Q000276:immunology; D015815:Cell Adhesion Molecules; D005260:Female; D005353:Fibronectins / Q000494:pharmacology; D006801:Humans; D007136:Immunoglobulins / Q000378:metabolism; D016023:Integrins / Q000037:antagonists & inhibitors* / Q000378:metabolism / Q000502:physiology; D036341:Intercellular Signaling Peptides and Proteins; D008969:Molecular Sequence Data; D009088:Mucoproteins / Q000378:metabolism; D009842:Oligopeptides / Q000378:metabolism / Q000494:pharmacology*; D010455:Peptides / Q000494:pharmacology; D010456:Peptides, Cyclic / Q000378:metabolism / Q000494:pharmacology*; D011485:Protein Binding / Q000276:immunology; D011817:Rabbits; D019010:Vascular Cell Adhesion Molecule-1 / Q000378:metabolism
D015815:Cell Adhesion Molecules; D005353:Fibronectins; D007136:Immunoglobulins; D016023:Integrins; D036341:Intercellular Signaling Peptides and Proteins; C504265:MADCAM1 protein, human; D009088:Mucoproteins; D009842:Oligopeptides; D010455:Peptides; D010456:Peptides, Cyclic; D019010:Vascular Cell Adhesion Molecule-1; C076687:CS1 peptide