Design and evaluation of thioalkylated mannose-modified dendrimer (G3)/α-cyclodextrin conjugates as antigen-presenting cell-selective siRNA carriers.

To design and evaluate the potential use of thioalkylated mannose-modified dendrimer (generation 3; G3) conjugates with α-cyclodextrin (Man-S-α-CDE (G3)) as novel antigen-presenting cell (APC)-selective siRNA carriers, we investigated the RNAi effects of siRNA complexes with Man-S-α-CDEs (G3). Man-S-α-CDE (G3, average degree of substitution of mannose (DSM) 4)/siRNA complex had the potent RNAi effects in both NR8383 cells, a rat alveolar macrophage cell line, and JAWSII cells, a mouse dendritic cell line, through adequate physicochemical properties, mannose receptor (MR)-mediated cellular uptake, and efficient phagosomal escape of the siRNA complex. In addition, cytotoxic activities of the siRNA complexes with α-CDE (G3, DS2) and Man-S-α-CDE (G3, DSM4) were almost negligible up to a charge ratio of 100 (carrier/siRNA). Taken together, these results suggest that Man-S-α-CDE (G3, DSM4) has the potential for a novel APC-selective siRNA carrier.