In vitro assessment of nanoparticle design for targeting and modulating dendritic cells (DCs)

Abstract

Rationale DCs are critical in immunoregulation, and are known to express high levels of C-type lectin receptors, such as mannose receptor, suggesting a potential utility for the design of strategies targeting and modulating DCs. The potential use of chitosan nanoparticle formulations and mannoside-containing neoglycoproteins was, therefore, examined. Methods DCs were derived from IL-4- and GMCSF-treated monocytes. Low and high molecular weight (MW; 6-19 KD and 310-390 KD, respectively) chitosan nanoparticles were formulated to contain a marker gene encoding the green fluorescence protein (pGFP). The transfection efficiency was assessed by immunofluorence microscopy. DCs were incubated with varying concentrations (0.3 and 1 μM) of bovine serum albumin (BSA) based neoglycoproteins with different numbers of mannose (Man) residues for 4 hrs, and the cytokine gene expression for IL-12, IL-23 and IL-10 was evaluated by RT-PCR. Results Immunofluorecence analysis of pGFP-tranfected DCs demonstrated that the highest transfection efficacy was seen in cells transfected with low MW chitosan nanoparticles. Analyses of five different sets of Man-BSA neoglycoproteins revealed that Man 32-BSA significantly induced gene expression for IL-12, IL-23 and IL-10, while Gal 34–BSA with the same spacer linker as Man-BSA showed no effect. Interestingly, when Man 23- and Man 40-BSA with a different linker were used, higher concentrations (≥1μM) were required to induce the gene expression. Conclusion Chitosan-DNA nanoparticles are potentially useful for gene transfection of DC. The number of mannose residues and the type of linkers in mannoside-containing neoglycoproteins influence the capacity to induce Th1 cytokine expression, which are critical in nanoparticle design.