G-rich motifs within phosphorothioate-based antisense oligonucleotides (ASOs) drive activation of FXN expression through indirect effects
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ABSTRACT:
PROVIDER: PRJNA846268 | ENA |
REPOSITORIES: ENA
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Project description:Evaluation of the effect of 3 ASOs targeting FXN on mRNA levels
2022-10-28 | GSE205526 | GEO
Project description:Friedreich's ataxia is an incurable disease caused by frataxin (FXN) protein deficiency, which is mostly induced by GAA repeat expansion in intron 1 of the FXN gene. Here, we identified antisense oligonucleotides (ASOs), complementary to two regions within the first intron of FXN pre-mRNA, which could increase FXN mRNA by ∼2-fold in patient fibroblasts. The increase in FXN mRNA was confirmed by the identification of multiple overlapping FXN-activating ASOs at each region, two independent RNA quantification assays, and normalization by multiple housekeeping genes. Experiments on cells with the ASO-binding sites deleted indicate that the ASO-induced FXN activation was driven by indirect effects. RNA sequencing analyses showed that the two ASOs induced similar transcriptome-wide changes, which did not resemble the transcriptome of wild-type cells. This RNA-seq analysis did not identify directly base-paired off-target genes shared across ASOs. Mismatch studies identified two guanosine-rich motifs (CCGG and G4) within the ASOs that were required for FXN activation. The phosphorodiamidate morpholino oligomer analogs of our ASOs did not activate FXN, pointing to a PS-backbone-mediated effect. Our study demonstrates the importance of multiple, detailed control experiments and target validation in oligonucleotide studies employing novel mechanisms such as gene activation.
| S-EPMC9825156 | biostudies-literature
Project description:We investigated whether pharamacological inhibition of Smyd3 by antisense oligonucleotides (ASOs) can influence diethylnitrosamine (DEN)-induced liver cancer development. Our phenotypic analyses, among others, included gene expression profiling.
2020-06-24 | GSE153077 | GEO
Project description:Oligonucleotides and nucleic acid analogues that alter gene expression are showing therapeutic promise for selected human diseases. The modification of synthetic nucleic acids to protect against nuclease degradation and to influence drug function is common practice, however, such modifications may also confer unexpected physicochemical and biological properties. Here we report backbone-specific effects of modified oligonucleotides on subnuclear organelles, altered distribution of nuclear proteins, the appearance of novel structured nuclear inclusions, and modification of RNA processing in cultured cells transfected with antisense oligonucleotides on a phosphorothioate backbone. Phosphodiester and phosphorodiamidate morpholino oligomers elicited no such consequences. Disruption of subnuclear structures and proteins elicit severe phenotypic disturbances, revealed by transcriptomic analysis of fibroblasts exhibiting such disruption. These data suggest that the toxic effects and adverse events reported after clinical evaluation of phosphorothioate nucleic acid drugs may be mediated, at least in part, by non-specific interaction of nuclear components with the phosphorothioate backbone. The effects of antisense oligonucleotide transfection on morphology of subnuclear organelles, localisation of nuclear proteins and impact on RNA processing were examined in primary human cells.
2022-03-23 | GSE121713 | GEO
Project description:Molecular phenotyping quantifies expression of pathway reproter genes by next-generation sequencing of pre-defined amplicons. We applied the technology to quantify pathway-level impact of ASOs to PTECs in the presence and absence of exogeneous EGF.
2017-03-13 | GSE83392 | GEO
Project description:Antisense oligonucleotides (ASOs) are being actively investigated as potential therapeutics for a broad range of neurodegenerative diseases. While these small oligonucleotides have been effective in the clinic, many basic questions regarding ASO internalization, trafficking, and modes of enhancing delivery remain. To address these questions, we investigated how lipid nanoparticle (LNP) delivery affects ASO uptake and distribution in the brain. We show that ASOs are internalized and active in central nervous system (CNS) cell types both in vivo and in vitro. While differential cellular activity and polarization states do not affect ASO potency, encapsulating ASOs in LNPs increases ASO activity up to 100-fold in cultured CNS cells. This dramatic increase in efficacy is facilitated by the intracellular trafficking of ASOs away from lysosomes or enhanced ASO uptake, which is cell-type-specific. We assessed the translatability of these results by screening ASO-LNPs in vitro and intracerebroventricularly injecting top performing formulations in mice. ASO-LNP delivery induced a strong ASO-dependent microgliosis response in the brain revealing that LNP encapsulation cannot mask ASO-mediated toxicity. However, LNP-delivered ASOs did not downregulate mRNA levels in bulk tissue due to changes in ASO distribution. While ASOs distribute widely across the brain after bulk injection, ASO-LNPs are preferentially internalized by cells lining the blood vessels and ventricles. Consistent with our findings in cells, ASOs localize to the endolysosomal system following both ASO and ASO-LNP delivery in the brain as determined using immunoelectron microscopy. These data provide valuable insights into how LNPs regulate ASO uptake and distribution in the brain, and support further development of ASO-LNPs for treating CNS disorders.
2023-05-15 | GSE220777 | GEO
Project description:Heterozygous GRN (progranulin) mutations cause frontotemporal dementia (FTD) due to haploinsufficiency, and increasing progranulin levels is a major therapeutic goal. Several microRNAs, including miR-29b, negatively regulate progranulin protein levels. Antisense oligonucleotides (ASOs) are emerging as a promising therapeutic modality for neurological diseases, but strategies for increasing target protein levels are limited. Here, we tested the efficacy of ASOs as enhancers of progranulin expression by sterically blocking the miR-29b binding site in the 3' UTR of the human GRN mRNA. We found 16 ASOs that increase progranulin protein in a dose-dependent manner in neuroglioma cells. A subset of these ASOs also increased progranulin protein in iPSC-derived neurons and in a humanized GRN mouse model. In FRET-based assays, the ASOs effectively competed miR-29b from binding to the GRN 3' UTR RNA. The ASOs increased levels of newly synthesized progranulin protein by increasing its translation, as revealed by polysome profiling. Together, our results demonstrate that ASOs can be used to effectively increase target protein levels by partially blocking miR binding sites. This ASO strategy may be therapeutically feasible for progranulin-deficient FTD as well as other conditions of haploinsufficiency.
2022-08-01 | GSE188498 | GEO
Project description:Circular RNAs (circRNAs) constitute an abundant class of covalently closed non-coding RNA molecules that are formed by backsplicing from eukaryotic protein-coding genes. Recent studies have shown that circRNAs can act as microRNA or protein decoys as well as transcriptional regulators. However, the functions of most circRNAs are still poorly understood. Because circRNA sequences overlap with their linear parent transcripts, depleting specific circRNAs without affecting host gene expression remains a challenge. Here, we assessed the utility of LNA-modified antisense oligonucleotides (ASOs) to knock down circRNAs for loss-of-function studies. We identified 5807 circRNAs in total RNA sequencing data from 4 liver cancer cell lines and used the back splice junction (BSJ) sequences of 7 validated circRNAs as target sites for designing different LNA-modified ASOs for circRNA knockdown. We found that while most RNase H-dependent gapmer ASOs mediate effective knockdown of their target circRNAs, some gapmers reduce the levels of the linear parent transcript and may also cause degradation of unintended off-targets. The circRNA targeting specificity can be enhanced using design-optimized gapmer ASOs or LNA/DNA mixmer ASOs, which display potent and specific circRNA knockdown with a minimal effect on the host genes or predicted off-targets. In summary, our results demonstrate that LNA-modified ASOs complementary to BSJ sequences mediate robust knockdown of circRNAs in vitro and, thus, represent a useful tool to explore the biological roles of circRNAs in loss-of-function studies in cultured cells and animal models.
2022-11-01 | GSE145592 | GEO
Project description:This study examined the effects of antisense oligonucleotides (ASOs) on the muscle transcriptome in a transgenic mouse model of myotonic dystrophy. Two ASOs were tested in HSALR transgenic mice. Both of the ASOs targeted mRNA from a human skeletal actin (hACTA1) transgene. This transgene contains an expanded CTG repeat in the 3M-bM-^@M-^Y untranslated region (UTR) (Mankodi et al M-bM-^@M-^\Myotonic dystrophy in transgenic mice expressing an expanded CUG repeatM-bM-^@M-^] Science 2000; 289:1769-72). ASO 445235 targeted the hACTA1 transcript in the 3M-bM-^@M-^Y UTR, downstream from the expanded repeat. ASO 190401 targeted the hACTA1 transcript in the coding region. The HSALR mice received 4 weeks of biweekly subcutaneous injections of vehicle (saline), ASO 190401, or ASO 445236 (n = 4 per group), at a dose of 25 mg/kg per injection. Wild-type mice of the same strain background received saline injections (n = 4). One week after the final injection, quadriceps muscle was harvested for RNA analysis. Four conditions, four arrays per condition, to compare WT and HSALR trangenic mice without treatment (saline) and to examine the effect of two oligos (vs. saline) in the HSALR transgenic mice.
2012-06-27 | E-GEOD-38962 | biostudies-arrayexpress
Project description:We used scRNA-seq to assess the differential effect of Smyd3 ASOs on the transcriptomic profile of different cell types in the TME of MOC1 tumors.
2024-10-10 | GSE273507 | GEO