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Project description:RNase H dependent Antisense oligonucleotides in the nucleus causes transcription termination
| PRJNA551276 | ENA
Project description:Antisense oligonucleotide (ASO) has the potential to induce off-target effects due to complementary binding between the ASO and unintended RNA with a sequence similar to the target RNA. In this study, we evaluated off-target effects of gapmer ASOs, which cleave the target RNA in an RNase H-dependent manner, by introducing the ASO into human cells and performing microarray analysis. Our data indicate that gapmer ASOs induce off-target effects depending on the degree of complementarity between the ASO and off-target candidate genes. Based on our results, we also propose a scheme for assessment of off-target effects of gapmer ASOs.
2021-12-08 | GSE190473 | GEO
Project description:RNase H1-dependent antisense oligonucleotides (ASOs) are active in reducing levels of both cytoplasmic mRNAs and nuclear retained RNAs. Although ASO activity in the nucleus has been well demonstrated, the cytoplasmic activity of ASOs is less clear. Using kinetic and subcellular fractionation studies, we evaluated ASO activity in the cytoplasm. Upon transfection, ASOs targeting exonic regions rapidly reduced cytoplasmically enriched mRNAs, whereas an intron-targeting ASO that only degrades the nuclear pre-mRNA reduced mRNA levels at a slower rate, similar to normal mRNA decay. Importantly, some exon-targeting ASOs can rapidly and vigorously reduce mRNA levels without decreasing pre-mRNA levels, suggesting that pre-existing cytoplasmic mRNAs can be cleaved by RNase H1-ASO treatment. In addition, we expressed a cytoplasm-localized mutant 7SL RNA that contains a partial U16 small nucleolar RNA (snoRNA) sequence. Treatment with an ASO simultaneously reduced both the nuclear U16 snoRNA and the cytoplasmic 7SL mutant RNA as early as 30 min after transfection in an RNase H1-dependent manner. Both the 5' and 3' cleavage products of the 7SL mutant RNA were accumulated in the cytoplasm. Together, these results demonstrate that RNase H1-dependent ASOs are robustly active in both the cytoplasm and nucleus.
| S-EPMC5589097 | biostudies-literature
Project description:RNase H-dependent gapmer antisense oligonucleotides (ASOs) are a promising therapeutic approach via sequence-specific binding to and degrading target RNAs. However, the efficacy and mechanism of antiviral gapmer ASOs have remained unclear. Here, we investigated the inhibitory effects of gapmer ASOs containing locked nucleic acids (LNA gapmers) on proliferating a mosquito-borne flavivirus, Japanese encephalitis virus (JEV), with high mortality. We designed several LNA gapmers targeting the 3' untranslated region of JEV genomic RNAs. In vitro screening by plaque assay using Vero cells revealed that LNA gapmers targeting a stem-loop region effectively inhibit JEV proliferation. Cell-based and RNA cleavage assays using mismatched LNA gapmers exhibited an underlying mechanism where the inhibition of viral production results from JEV RNA degradation by LNA gapmers in a sequence- and modification-dependent manner. Encouragingly, LNA gapmers potently inhibited the proliferation of five JEV strains of predominant genotypes I and III in human neuroblastoma cells without apparent cytotoxicity. Database searching showed a low possibility of off-target binding of our LNA gapmers to human RNAs. The target viral RNA sequence conservation observed here highlighted their broad-spectrum antiviral potential against different JEV genotypes/strains. This work will facilitate the development of an antiviral LNA gapmer therapy for JEV and other flavivirus infections.
| S-EPMC10573891 | biostudies-literature
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:Heart failure (HF) is a major cause of morbidity and mortality worldwide, but therapeutic intervention remains limited despite recent improvements. Aberrant Ca2+ handling is a key feature of HF pathophysiology. Restoring the Ca2+ regulating machinery is an attractive therapeutic strategy supported by genetic and pharmacological proof of concept studies. Here, we studied antisense oligonucleotides (ASOs) as a novel therapeutic modality, interfering with the PLN/SERCA2a interaction by targeting Pln mRNA for downregulation in the heart of murine HF models. Mice harboring the PLN R14del pathogenic variant recapitulate the human dilated cardiomyopathy (DCM) phenotype; subcutaneously administrated PLN-ASO prevented PLN protein aggregation, cardiac dysfunction, and led to a 3-fold increase in survival rate. In another genetic DCM mouse model, unrelated to PLN (as a disease driver) (Cspr3/Mlp-/-), PLN-ASO also reversed the HF phenotype. Finally, in rats with myocardial infarction, progression of left ventricular dilatation was prevented by PLN-ASO treatment, which also improved left ventricular contractility. Thus, our data establish PLN-ASO as a possible precision medicine for genetic cardiomyopathy as well as general HF.
2021-06-11 | GSE151156 | GEO
Project description:Antisense oligonucleotides that are dependent on RNase H for cleavage and subsequent degradation of complementary RNA are being developed as therapeutics. Besides the intended RNA target, such oligonucleotides may also cause degradation of unintended RNA off-targets by binding to partially complementary target sites. Here, we characterized the global effects on the mouse liver transcriptome of four oligonucleotides designed as gapmers, two targeting Apob and two targeting Pcsk9, all in different regions on their respective intended targets. This study design allowed separation of intended- and off-target effects on the transcriptome for each gapmer. Next, we used sequence analysis to identify possible partially complementary binding sites among the potential off-targets, and validated these by measurements of melting temperature and RNase H-cleavage rates. Generally, our observations were as expected in that fewer mismatches or bulges in the gapmer/transcript duplexes resulted in a higher chance of those duplexes being effective substrates for RNase H. Follow-up experiments in mice and cells show, that off-target effects can be mitigated by ensuring that gapmers have minimal sequence complementarity to any RNA besides the intended target, and that they do not have exaggerated binding affinity to the intended target.
| S-EPMC6009603 | biostudies-literature
Project description:An RNase H-dependent antisense oligonucleotide (ASO), having the 2'-O-(2-N-methylcarbamoylethyl) (MCE) modification, was evaluated in vitro and in vivo. The antisense activities of an ASO having the MCE modification were comparable with those of an ASO having the 2'-O-methoxyethyl (MOE) modification in both in vitro and in vivo experiments. In contrast, the hepatotoxic potential of the ASO having the MCE modification was lower than that of the ASO having the MOE modification. Thus, these findings suggested that the MCE modification could be used as an alternative to the MOE modification.
| S-EPMC6157346 | biostudies-literature
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:RNase H1-dependent antisense oligonucleotides (ASOs) can degrade complementary RNAs in both the nucleus and the cytoplasm. Since cytoplasmic mRNAs are actively engaged in translation, ASO activity may thus be affected by translating ribosomes that scan the mRNAs. Here we show that mRNAs associated with ribosomes can be cleaved using ASOs and that translation can alter ASO activity. Translation inhibition tends to increase ASO activity when targeting the coding regions of efficiently translated mRNAs, but not nuclear non-coding RNAs or less efficiently translated mRNAs. Increasing the level of RNase H1 protein eliminated the enhancing effects of translation inhibition on ASO activity, suggesting that RNase H1 recruitment to ASO/mRNA heteroduplexes is a rate limiting step and that translating ribosomes can inhibit RNase H1 recruitment. Consistently, ASO activity was not increased by translation inhibition when targeting the 3' UTRs, independent of the translation efficiency of the mRNAs. Contrarily, the activity of 3' UTR-targeting ASOs tended to be reduced upon translation inhibition, likely due to decreased accessibility. These results indicate that ASO activity can be affected by the translation process, and the findings also provide important information toward helping better ASO drug design.
| S-EPMC5758896 | biostudies-other