The Role of Dimension in Multivalent Binding Events: Structure–Activity Relationship of Dendritic Polyglycerol Sulfate Binding to L‐Selectin in Correlation with Size and Surface Charge Density

Abstract

L-, P-, and E-Selectin are cell adhesion molecules that play a crucial role in leukocyte recruitment from the blood stream to the afflicted tissue in an acute and chronic inflammatory setting. Since selectins mediate the initial contact of leukocytes to the vascular endothelium, they have evolved as a valuable therapeutic target in diseases related to inflammation by inhibition of the physiological selectin-ligand interactions. In a previous study, it was demonstrated that dPGS, a fully synthetic heparin analogue, works as an efficient inhibitor towards L- and P-selectin in vitro as well as in vivo. Herein, the focus is directed towards the effect of size and charge density of the polyanion. The efficiency of L-selectin inhibition via an SPR-based in vitro assay and a cell-based flow chamber assay is investigated with dPGS ranging from approximately 4 to 2000 kDa. SPR measurements show that the inhibitory potential of highly sulfated dPGS increases with size and charge density. Thereby, IC(50) values from the micromolar to the low picomolar range are determined. The same tendency could be observed in a cell-based flow chamber assay with three representative dPGS samples. This structure-affinity relationship of dPGS suggests that the strong inhibitory potential of dPGS is not only based on the strong electrostatic interaction with areas of cationic surface potential on L-selectin but is also due to a steric shielding of the carbohydrate binding site by large, flexible dPGS particles.

The influence of surface charge on serum protein interaction and cellular uptake: studies with dendritic polyglycerols and dendritic polyglycerol-coated gold nanoparticles

“…[27][28][29] Sulfated dendritic polyglycerol (dPGS) has been shown to possess anti-inflammatory properties in vivo and in vitro with the relevant cellular targets being L-and P-selectins. 28,30,31 The aim of this study was to investigate the influence of size and charge of dPGs on the interactions with serum proteins and to study the influence of the protein corona on cellular uptake in human CD14…”

Interaction between synthetic particles and biomacromolecules: fundamental study of nonspecific interaction and design of nanoparticles that recognize target molecules

“…Thus, it was concluded that the modified dPG interacted with L-selectin through = Figure 8 Schematic illustration of the library of anionic dPG. [43][44][45] Interaction between synthetic particles and biomacromolecules Y Hoshino et al multipoint electrostatic interactions. 43 In addition, as the size of the dPG significantly affected the suppression of selectin activity, it was suggested that the strong inhibitory activity of dPG is not only on a strong electrostatic interaction but also on steric shielding by large flexible dPG particles.…”

Multivalenz als chemisches Organisations‐ und Wirkprinzip

“…[199] Während der monovalente Ligand einen IC 50 In Analogie zu den sulfatierten multivalenten Glycokonjugaten konnte mit dendritischem Polyglycerinsulfat (dPGS) eine hochaktive anti-inflammatorische Verbindung identifiziert werden, die im nanomolaren Bereich an L-und P-Selectine sowie andere Entzündungsmediatoren bindet (siehe Abschnitt 4.3). [72,201,202] Auch wenn auf einem sphärischen oder flächigen Polymer die Präsentation der Liganden nicht mehr rational auf die komplementäre Rezeptorpositionierung abgestimmt, sondern eher statistisch verteilt ist (siehe Abschnitt 3.1), resultiert eine signifikante Inhibitionsverstärkung, die nun mithilfe theoretischer Methoden in Einklang mit der Bindungskinetik (z. B. der Mçglichkeit zur vermehrten Rückbindung der Liganden) und Thermodynamik gebracht werden kann.…”