Polyelectrolyte Coating of Ferumoxytol Differentially Impacts on Labeling of Inflammatory and Steady-State Dendritic Cell Subtypes

Abstract

Engineered magnetic nanoparticles (MNPs) are emerging as advanced tools for medical applications. The coating of MNPs using polyelectrolytes (PEs) is a versatile means to tailor MNP properties and is used to optimize MNP functionality. Dendritic cells (DCs) are critical regulators of adaptive immune responses. Functional distinct DC subsets exist either under steady-state or inflammatory conditions, which are explored for the specific treatment of various diseases, such as cancer, autoimmunity or transplant rejection. Here, the impact of PE coating of ferumoxytol for uptake into both inflammatory and steady-state DCs and cellular responses to the MNP labeling is addressed. Labeling efficiency by uncoated and PE-coated ferumoxytol is highly variable in different DC subsets, and PE coating significantly improves the labeling of steady-state DCs. Uncoated ferumoxytol results in increased cytotoxicity of steady-state DCs after labeling that is abolished by the PE coating, while no increased cell death is observed in inflammatory DCs. Furthermore, uncoated and PE-coated ferumoxytol appears immunologically inert in inflammatory DCs but induces activation of steady-state DCs. These results show that PE coating of MNPs can be applied to endow particles with desired properties for enhanced uptake and cell type-specific responses in distinct target DC populations.