TY - JOUR

T1 - Mesyl Phosphoramidate Oligonucleotides as Potential Splice-Switching Agents

T2 - Impact of Backbone Structure on Activity and Intracellular Localization

AU - Hammond, Suzan M.

AU - Sergeeva, Olga V.

AU - Melnikov, Pavel A.

AU - Goli, Larissa

AU - Stoodley, Jessica

AU - Zatsepin, Timofei S.

AU - Stetsenko, Dmitry A.

AU - Wood, Matthew J.A.

N1 - Funding Information: S.M.H. funding comes from the Medical Research Council (MRC grant no. MR/R025312/1). The SMA mouse model and patient fibroblasts were obtained through an MTA. Microscopy studies were supported by the Institute of Cytology and Genetics (Novosibirsk, Russia) project No. 0324-2019-0042-C-01. T.S.Z. and D.A.S. acknowledge financial support from the Russian Foundation for Basic Research (D.A.S. from grant nos. 18-515-57006, 18-29-09045, and 18-29-08062, and T.S.Z. from grant no. 19-04-00298). Publisher Copyright: © Copyright 2021, Mary Ann Liebert, Inc., publishers 2021.

PY - 2021/6

Y1 - 2021/6

N2 - A series of 2′-deoxy and novel 2′-O-methyl and 2′-O-(2-methoxyethyl) (2′-MOE) oligonucleotides with internucleotide methanesulfonyl (mesyl, μ) or 1-butanesulfonyl (busyl, β) phosphoramidate groups has been synthesized for evaluation as potential splice-switching oligonucleotides. Evaluation of their splice-switching activity in spinal muscular atrophy patient-derived fibroblasts revealed no significant difference in splice-switching efficacy between 2′-MOE mesyl oligonucleotide and the corresponding phosphorothioate (nusinersen). Yet, a survival study with model neonatal mice has shown the antisense 2′-MOE mesyl oligonucleotide to be inferior to nusinersen at the highest dose of 40 mg/kg. A reason for their lower activity in vivo as ascertained by cellular uptake study by fluorescent confocal microscopy in HEK293 cell line could possibly be ascribed to compromised endosomal release and/or nuclear uptake of the 2′-OMe or 2′-MOE μ- and β-oligonucleotides compared to their phosphorothioate analog.

AB - A series of 2′-deoxy and novel 2′-O-methyl and 2′-O-(2-methoxyethyl) (2′-MOE) oligonucleotides with internucleotide methanesulfonyl (mesyl, μ) or 1-butanesulfonyl (busyl, β) phosphoramidate groups has been synthesized for evaluation as potential splice-switching oligonucleotides. Evaluation of their splice-switching activity in spinal muscular atrophy patient-derived fibroblasts revealed no significant difference in splice-switching efficacy between 2′-MOE mesyl oligonucleotide and the corresponding phosphorothioate (nusinersen). Yet, a survival study with model neonatal mice has shown the antisense 2′-MOE mesyl oligonucleotide to be inferior to nusinersen at the highest dose of 40 mg/kg. A reason for their lower activity in vivo as ascertained by cellular uptake study by fluorescent confocal microscopy in HEK293 cell line could possibly be ascribed to compromised endosomal release and/or nuclear uptake of the 2′-OMe or 2′-MOE μ- and β-oligonucleotides compared to their phosphorothioate analog.

KW - 2′-methoxyethyl

KW - intracellular distribution

KW - nusinersen

KW - spinal muscular atrophy

KW - splice switching

UR - http://www.scopus.com/inward/record.url?scp=85107621992&partnerID=8YFLogxK

U2 - 10.1089/nat.2020.0860

DO - 10.1089/nat.2020.0860

M3 - Article

C2 - 33989066

AN - SCOPUS:85107621992

VL - 31

SP - 190

EP - 200

JO - Nucleic Acid Therapeutics

JF - Nucleic Acid Therapeutics

SN - 2159-3337

IS - 3

ER -