title: Selective gene silencing in activated leukocytes by targeting siRNAs to the integrin lymphocyte function-associated antigen-1.
abstract: Silencing gene expression by RNAi is a powerful method for exploring gene function and validating drug targets and potentially for therapy. Lymphocytes and other primary blood cells are resistant to lipid-based transfection in vitro and are difficult to target in vivo. We show here that antibody-protamine fusion proteins targeting the human integrin lymphocyte function-associated antigen-1 (LFA-1) efficiently deliver siRNAs and specifically induce silencing in primary lymphocytes, monocytes, and dendritic cells. Moreover, a fusion protein constructed from an antibody that preferentially recognizes activation-dependent conformational changes in LFA-1 selectively targets activated leukocytes and can be used to suppress gene expression and cell proliferation only in activated lymphocytes. The siRNA-fusion protein complexes do not cause lymphocyte activation or induce IFN responses. K562 cells expressing latent WT or constitutively activated LFA-1 engrafted in the lungs of SCID mice are selectively targeted by intravenously injected fusion protein-siRNA complexes, demonstrating the potential in vivo applicability of LFA-1-directed siRNA delivery.
authors.affiliation: CBR Institute for Biomedical Research, Harvard Medical School, 200 Longwood Avenue, Boston, MA 02115, USA.
authors.forename: Dan
authors.initials: D
authors.lastname: Peer
authors.forename: Pengcheng
authors.initials: P
authors.lastname: Zhu
authors.forename: Christopher V
authors.initials: CV
authors.lastname: Carman
authors.forename: Judy
authors.initials: J
authors.lastname: Lieberman
authors.forename: Motomu
authors.initials: M
authors.lastname: Shimaoka
mesh_terms: D000818:Animals; D034961:Antigens, Nuclear / Q000096:biosynthesis; D002448:Cell Adhesion; D049109:Cell Proliferation; D004268:DNA-Binding Proteins / Q000096:biosynthesis; D004305:Dose-Response Relationship, Drug; D020868:Gene Silencing; D006801:Humans; D020014:K562 Cells; D000072200:Ku Autoantigen; D016169:Lymphocyte Function-Associated Antigen-1 / Q000378:metabolism / Q000502:physiology*; D051379:Mice; D016513:Mice, SCID; D034741:RNA, Small Interfering / Q000378:metabolism; D019713:Receptors, CCR5 / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000737:chemistry; D013601:T-Lymphocytes / Q000378:metabolism
chemical_list: D034961:Antigens, Nuclear; D004268:DNA-Binding Proteins; D016169:Lymphocyte Function-Associated Antigen-1; D034741:RNA, Small Interfering; D019713:Receptors, CCR5; D011993:Recombinant Fusion Proteins; C000606509:Xrcc6 protein, human; C000606510:Xrcc6 protein, mouse; D000072200:Ku Autoantigen