title: SIDT2 mediates gymnosis, the uptake of naked single-stranded oligonucleotides into living cells.
abstract: Single-stranded oligonucleotides (ssOligos) are efficiently taken up by living cells without the use of transfection reagents. This phenomenon called 'gymnosis' enables the sequence-specific silencing of target genes in various types of cells. Several antisense ssOligos are used for the treatment of human diseases. However, the molecular mechanism underlying the uptake of naked ssOligos into cells remains to be elucidated. Here, we show that systemic RNA interference deficient-1 (SID-1) transmembrane family 2 (SIDT2), a mammalian ortholog of the Caenorhabditis elegans double-stranded RNA channel SID-1, mediates gymnosis. We show that the uptake of naked ssOligos into cells is significantly downregulated by knockdown of SIDT2. Furthermore, knockdown of SIDT2 inhibited the effect of antisense RNA mediated by gymnosis. Overexpression of SIDT2 enhanced the uptake of naked ssOligos into cells, while a single amino acid mutation in SIDT2 abolished this effect. Our findings highlight the mechanism of extra- and intracellular RNA transport and may contribute to the further development of nucleic acid-based therapies.
authors.affiliation: a Department of Degenerative Neurological Diseases , National Institute of Neuroscience, National Center of Neurology and Psychiatry , Kodaira, Tokyo , Japan.
authors.forename: Masayuki
authors.initials: M
authors.lastname: Takahashi
authors.affiliation: a Department of Degenerative Neurological Diseases , National Institute of Neuroscience, National Center of Neurology and Psychiatry , Kodaira, Tokyo , Japan.|b Department of Neurology, Interdisciplinary Graduate School of Medicine and Engineering , University of Yamanashi , Yamanashi , Japan.
authors.forename: Viorica Raluca
authors.initials: VR
authors.lastname: Contu
authors.affiliation: a Department of Degenerative Neurological Diseases , National Institute of Neuroscience, National Center of Neurology and Psychiatry , Kodaira, Tokyo , Japan.
authors.forename: Chihana
authors.initials: C
authors.lastname: Kabuta
authors.affiliation: a Department of Degenerative Neurological Diseases , National Institute of Neuroscience, National Center of Neurology and Psychiatry , Kodaira, Tokyo , Japan.
authors.forename: Katsunori
authors.initials: K
authors.lastname: Hase
authors.affiliation: a Department of Degenerative Neurological Diseases , National Institute of Neuroscience, National Center of Neurology and Psychiatry , Kodaira, Tokyo , Japan.
authors.forename: Yuuki
authors.initials: Y
authors.lastname: Fujiwara
authors.affiliation: a Department of Degenerative Neurological Diseases , National Institute of Neuroscience, National Center of Neurology and Psychiatry , Kodaira, Tokyo , Japan.
authors.forename: Keiji
authors.initials: K
authors.lastname: Wada
authors.affiliation: a Department of Degenerative Neurological Diseases , National Institute of Neuroscience, National Center of Neurology and Psychiatry , Kodaira, Tokyo , Japan.
authors.forename: Tomohiro
authors.identifier: 0000-0002-3058-2596
authors.initials: T
authors.lastname: Kabuta
mesh_terms: D000818:Animals; D002460:Cell Line; D005347:Fibroblasts / Q000166:cytology / Q000378:metabolism; D005456:Fluorescent Dyes / Q000737:chemistry; D015870:Gene Expression; D006367:HeLa Cells; D006576:Heterocyclic Compounds, 4 or More Rings / Q000737:chemistry; D006801:Humans; D051379:Mice; D035683:MicroRNAs / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism; D009154:Mutation; D033704:Nucleotide Transport Proteins / Q000235:genetics* / Q000378:metabolism; D016376:Oligonucleotides, Antisense / Q000235:genetics* / Q000378:metabolism; D010957:Plasmids / Q000737:chemistry / Q000378:metabolism; D034622:RNA Interference; D034443:RNA Transport; D012235:Rhodamines / Q000378:metabolism; D013194:Staining and Labeling / Q000379:methods
chemical_list: D005456:Fluorescent Dyes; D006576:Heterocyclic Compounds, 4 or More Rings; C505362:MIRN16 microRNA, human; D035683:MicroRNAs; D033704:Nucleotide Transport Proteins; D016376:Oligonucleotides, Antisense; D012235:Rhodamines; C000613088:SIDT2 protein, human; C000607448:alexa 568; C029773:rhodamine B
keywords: Gymnosis; RNA channel; SIDT2; membrane protein; single-stranded oligonucleotides