Glucan particles for selective delivery of siRNA to phagocytic cells in mice
Interdisciplinary Graduate Program
Program in Molecular Medicine
Medical Subject Headings
3T3-L1 Cells; Animals; COS Cells; Cercopithecus aethiops; Gene Transfer Techniques; Male; Mice; Mice, Inbred C57BL; Particle Size; Phagocytes; RNA, Small Interfering; Saccharomyces cerevisiae; beta-Glucans
Biochemistry | Molecular Biology | Molecular genetics
Phagocytic macrophages and dendritic cells are desirable targets for potential RNAi (RNA interference) therapeutics because they often mediate pathogenic inflammation and autoimmune responses. We recently engineered a complex 5 component glucan-based encapsulation system for siRNA (small interfering RNA) delivery to phagocytes. In experiments designed to simplify this original formulation, we discovered that the amphipathic peptide Endo-Porter forms stable nanocomplexes with siRNA that can mediate potent gene silencing in multiple cell types. In order to restrict such gene silencing to phagocytes, a method was developed to entrap siRNA-Endo-Porter complexes in glucan shells of 2-4 μm diameter in the absence of other components. The resulting glucan particles containing fluorescently labelled siRNA were readily internalized by macrophages, but not other cell types, and released the labelled siRNA into the macrophage cytoplasm. Intraperitoneal administration of such glucan particles containing siRNA-Endo-Porter complexes to mice caused gene silencing specifically in macrophages that internalized the particles. These results from the present study indicate that specific targeting to phagocytes is mediated by the glucan, whereas Endo-Porter peptide serves both to anchor siRNA within glucan particles and to catalyse escape of siRNA from phagosomes. Thus we have developed a simplified siRNA delivery system that effectively and specifically targets phagocytes in culture or in intact mice.
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Citation: Tesz GJ, Aouadi M, Prot M, Nicoloro SM, Boutet E, Amano SU, Goller A, Wang M, Guo CA, Salomon WE, Virbasius JV, Baum RA, O'Connor MJ Jr, Soto E, Ostroff GR, Czech MP. Glucan particles for selective delivery of siRNA to phagocytic cells in mice. Biochem J. 2011 Jun 1;436(2):351-62. doi: 10.1042/BJ20110352.