title: Glucan particles for selective delivery of siRNA to phagocytic cells in mice.
abstract: 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.
authors.affiliation: Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA.
authors.forename: Gregory J
authors.initials: GJ
authors.lastname: Tesz
authors.forename: Myriam
authors.initials: M
authors.lastname: Aouadi
authors.forename: Matthieu
authors.initials: M
authors.lastname: Prot
authors.forename: Sarah M
authors.initials: SM
authors.lastname: Nicoloro
authors.forename: Emilie
authors.initials: E
authors.lastname: Boutet
authors.forename: Shinya U
authors.initials: SU
authors.lastname: Amano
authors.forename: Anca
authors.initials: A
authors.lastname: Goller
authors.forename: Mengxi
authors.initials: M
authors.lastname: Wang
authors.forename: Chang-An
authors.initials: CA
authors.lastname: Guo
authors.forename: William E
authors.initials: WE
authors.lastname: Salomon
authors.forename: Joseph V
authors.initials: JV
authors.lastname: Virbasius
authors.forename: Rebecca A
authors.initials: RA
authors.lastname: Baum
authors.forename: Mark J
authors.initials: MJ
authors.lastname: O'Connor
authors.forename: Ernesto
authors.initials: E
authors.lastname: Soto
authors.forename: Gary R
authors.initials: GR
authors.lastname: Ostroff
authors.forename: Michael P
authors.initials: MP
authors.lastname: Czech
mesh_terms: D041721:3T3-L1 Cells; D000818:Animals; D019556:COS Cells; D002522:Chlorocebus aethiops; D018014:Gene Transfer Techniques; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D010316:Particle Size; D010586:Phagocytes / Q000187:drug effects / Q000378:metabolism*; D011509:Proteoglycans; D034741:RNA, Small Interfering / Q000008:administration & dosage* / Q000235:genetics*; D012441:Saccharomyces cerevisiae / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D047071:beta-Glucans / Q000008:administration & dosage*
chemical_list: D011509:Proteoglycans; D034741:RNA, Small Interfering; D047071:beta-Glucans; C010770:polysaccharide-K