title: Sequence- and target-independent angiogenesis suppression by siRNA via TLR3.
abstract: Clinical trials of small interfering RNA (siRNA) targeting vascular endothelial growth factor-A (VEGFA) or its receptor VEGFR1 (also called FLT1), in patients with blinding choroidal neovascularization (CNV) from age-related macular degeneration, are premised on gene silencing by means of intracellular RNA interference (RNAi). We show instead that CNV inhibition is a siRNA-class effect: 21-nucleotide or longer siRNAs targeting non-mammalian genes, non-expressed genes, non-genomic sequences, pro- and anti-angiogenic genes, and RNAi-incompetent siRNAs all suppressed CNV in mice comparably to siRNAs targeting Vegfa or Vegfr1 without off-target RNAi or interferon-alpha/beta activation. Non-targeted (against non-mammalian genes) and targeted (against Vegfa or Vegfr1) siRNA suppressed CNV via cell-surface toll-like receptor 3 (TLR3), its adaptor TRIF, and induction of interferon-gamma and interleukin-12. Non-targeted siRNA suppressed dermal neovascularization in mice as effectively as Vegfa siRNA. siRNA-induced inhibition of neovascularization required a minimum length of 21 nucleotides, a bridging necessity in a modelled 2:1 TLR3-RNA complex. Choroidal endothelial cells from people expressing the TLR3 coding variant 412FF were refractory to extracellular siRNA-induced cytotoxicity, facilitating individualized pharmacogenetic therapy. Multiple human endothelial cell types expressed surface TLR3, indicating that generic siRNAs might treat angiogenic disorders that affect 8% of the world's population, and that siRNAs might induce unanticipated vascular or immune effects.
authors: Department of Ophthalmology, University of Kentucky, Lexington, Kentucky 40506, USA.
authors: Mark E
authors: ME
authors: Kleinman
authors: Kiyoshi
authors: K
authors: Yamada
authors: Atsunobu
authors: A
authors: Takeda
authors: Vasu
authors: V
authors: Chandrasekaran
authors: Miho
authors: M
authors: Nozaki
authors: Judit Z
authors: JZ
authors: Baffi
authors: Romulo J C
authors: RJ
authors: Albuquerque
authors: Satoshi
authors: S
authors: Yamasaki
authors: Masahiro
authors: M
authors: Itaya
authors: Yuzhen
authors: Y
authors: Pan
authors: Binoy
authors: B
authors: Appukuttan
authors: Daniel
authors: D
authors: Gibbs
authors: Zhenglin
authors: Z
authors: Yang
authors: Katalin
authors: K
authors: Karikó
authors: Balamurali K
authors: BK
authors: Ambati
authors: Traci A
authors: TA
authors: Wilgus
authors: Luisa A
authors: LA
authors: DiPietro
authors: Eiji
authors: E
authors: Sakurai
authors: Kang
authors: K
authors: Zhang
authors: Justine R
authors: JR
authors: Smith
authors: Ethan W
authors: EW
authors: Taylor
authors: Jayakrishna
authors: J
authors: Ambati
mesh_terms: D000818:Animals; D002460:Cell Line; D042783:Endothelial Cells / Q000378:metabolism; D015316:Genetic Therapy / Q000379:methods*; D006801:Humans; D007113:Immunity, Innate / Q000276:immunology*; D007371:Interferon-gamma / Q000276:immunology; D018664:Interleukin-12 / Q000276:immunology; D008268:Macular Degeneration / Q000150:complications / Q000235:genetics / Q000628:therapy; D051379:Mice; D008810:Mice, Inbred C57BL; D009389:Neovascularization, Pathologic / Q000235:genetics / Q000276:immunology* / Q000517:prevention & control* / Q000628:therapy; D034741:RNA, Small Interfering / Q000737:chemistry / Q000235:genetics / Q000276:immunology* / Q000378:metabolism*; D051196:Toll-Like Receptor 3 / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D042461:Vascular Endothelial Growth Factor A / Q000235:genetics
chemical_list: D034741:RNA, Small Interfering; D051196:Toll-Like Receptor 3; D042461:Vascular Endothelial Growth Factor A; D018664:Interleukin-12; D007371:Interferon-gamma