title: Evaluation of Receptor-Ligand Mechanisms of Dual-Targeted Particles to an Inflamed Endothelium.
abstract: Vascular-targeted carriers (VTCs) are designed as leukocyte mimics, decorated with ligands that target leukocyte adhesion molecules (LAMs) and facilitate adhesion to diseased endothelium. VTCs require different design considerations than other targeted particle therapies; adhesion of VTCs in regions with dynamic blood flow requires multiple ligand-receptor (LR) pairs that provide particle adhesion and disease specificity. Despite the ultimate goal of leukocyte mimicry, the specificity of multiple LAM-targeted VTCs remains poorly understood, especially in physiological environments. Here, we investigate particle binding to an inflamed mesentery via intravital microscopy using a series of particles with well-controlled ligand properties. We find that the total number of sites of a single ligand can drive particle adhesion to the endothelium, however, combining ligands that target multiple LR pairs provides a more effective approach. Combining sites of sialyl Lewis A (sLeA) and anti-intercellular adhesion molecule-1 (aICAM), two adhesive molecules, resulted in ~3-7-fold increase of adherent particles at the endothelium over single-ligand particles. At a constant total ligand density, a particle with a ratio of 75% sLeA: 25% aICAM resulted in more than 3-fold increase over all over other ligand ratios tested in ourin vivomodel. Combined within vitroandin silicodata, we find the best dual-ligand design of a particle is heavily dependent on the surface expression of the endothelial cells, producing better adhesion with more particle ligand for the lesser-expressed receptor. These results establish the importance of considering LR-kinetics in intelligent VTC ligand design for future therapeutics.
authors.affiliation: Department of Chemical Engineering, University of Michigan, Ann Arbor, MI 48109.
authors.forename: Catherine A
authors.initials: CA
authors.lastname: Fromen
authors.affiliation: Department of Chemical Engineering, University of Michigan, Ann Arbor, MI 48109.
authors.forename: Margaret B
authors.initials: MB
authors.lastname: Fish
authors.affiliation: Department of Chemical Engineering, University of Michigan, Ann Arbor, MI 48109.
authors.forename: Anthony
authors.initials: A
authors.lastname: Zimmerman
authors.affiliation: Department of Pharmacology, University of Michigan, Ann Arbor, MI 48109.
authors.forename: Reheman
authors.initials: R
authors.lastname: Adili
authors.affiliation: Department of Pharmacology, University of Michigan, Ann Arbor, MI 48109; Division of Cardiovascular Medicine, Samuel and Jean Frankel Cardiovascular Center, University of Michigan, Ann Arbor, MI 48109.
authors.forename: Michael
authors.initials: M
authors.lastname: Holinstat
authors.affiliation: Department of Chemical Engineering, University of Michigan, Ann Arbor, MI 48109.
authors.forename: Omolola
authors.initials: O
authors.lastname: Eniola-Adefeso
keywords: dual-targeted particle; intravital microscopy; leukomimietics; ligand-receptor pair; particle adhesion; vascular-targeted carrier