title: 2'-O-methyl-modified RNAs act as TLR7 antagonists.
abstract: RNA molecules such as single-stranded RNA (ssRNA) and small interfering RNA (siRNA) duplexes induce Toll-like receptor (TLR)-mediated immune stimulation after intracellular delivery. We have previously shown that selective incorporation of 2'-O-methyl (2'OMe) residues into siRNA abrogates cytokine production without reduction of gene silencing activity. Here we show that 2'OMe-modified RNA acts as a potent inhibitor of RNA-mediated cytokine induction in both human and murine systems. This activity does not require the direct incorporation of 2'OMe nucleotides into the immunostimulatory RNA or that the 2'OMe nucleotide-containing RNA be annealed as a complementary strand to form a duplex. Our results indicate that 2'OMe RNA acts as a potent antagonist of immunostimulatory RNA. We further show that 2'OMe RNA is able significantly to reduce both interferon-alpha (IFN-alpha) and interleukin-6 (IL-6) induction by the small-molecule TLR7 agonist loxoribine in human peripheral blood mononuclear cells (human PBMCs), in murine Flt3L dendritic cells (Flt3L DCs), and in vivo in mice. These results indicate that 2'OMe-modified RNA may have utility as an inhibitor of TLR7 with potential applications in the treatment of inflammatory and autoimmune diseases that involve TLR7-mediated immune stimulation.
authors.affiliation: Protiva Biotherapeutics, Burnaby, British Columbia, Canada.
authors.forename: Marjorie
authors.initials: M
authors.lastname: Robbins
authors.forename: Adam
authors.initials: A
authors.lastname: Judge
authors.forename: Lisa
authors.initials: L
authors.lastname: Liang
authors.forename: Kevin
authors.initials: K
authors.lastname: McClintock
authors.forename: Ed
authors.initials: E
authors.lastname: Yaworski
authors.forename: Ian
authors.initials: I
authors.lastname: MacLachlan
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D016207:Cytokines / Q000097:blood*; D005260:Female; D006151:Guanosine / Q000031:analogs & derivatives / Q000494:pharmacology; D006801:Humans; D007166:Immunosuppressive Agents / Q000008:administration & dosage / Q000494:pharmacology; D007275:Injections, Intravenous; D016898:Interferon-alpha / Q000097:blood; D007963:Leukocytes, Mononuclear / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D051379:Mice; D008807:Mice, Inbred BALB C; D034741:RNA, Small Interfering / Q000008:administration & dosage / Q000235:genetics / Q000494:pharmacology*; D051199:Toll-Like Receptor 7 / Q000037:antagonists & inhibitors* / Q000235:genetics
chemical_list: D016207:Cytokines; D007166:Immunosuppressive Agents; D016898:Interferon-alpha; D034741:RNA, Small Interfering; D051199:Toll-Like Receptor 7; D006151:Guanosine; C068562:loxoribine