Browse
Submit Data
Databases
API
Help

Dataset Information

0 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Synthesis and Antisense Properties of 2'?-F-Arabinouridine Modified Oligonucleotides with 4'-C-OMe Substituent.

ABSTRACT: A novel 2'-F,4'-C-OMe?arabinouridine (araU) was successfully synthesized and introduced into oligonucleotides. The oligonucleotide containing 2'-F,4'-C-OMe?araU exhibited improved nuclease resistance and RNA hybridizing selective ability relative to 2'-F?araU. In particular, when 2'-F,4'-C-OMe?araU inserted into C?H?F?C bonding-favorable 5'?uridine?purine?3' steps, the modified oligonucleotide showed remarkable binding affinity and selectivity to RNA complements. Thus, 2'-F,4'-C-OMe?araU has valuable antisense properties and can be used as novel chemical modification for antisense therapeutic strategy.

SUBMITTER: He XY

PROVIDER: S-EPMC6225415 | biostudies-literature | 2018 Sep

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Publications

Synthesis and Antisense Properties of 2'β-F-Arabinouridine Modified Oligonucleotides with 4'-C-OMe Substituent.

He Xiao-Yang XY Wang Jing J Lu Dan-Dan DD Wang Sheng-Qi SQ

Molecules (Basel, Switzerland) 20180917 9

A novel 2'-F,4'-C-OMe⁻arabinouridine (araU) was successfully synthesized and introduced into oligonucleotides. The oligonucleotide containing 2'-F,4'-C-OMe⁻araU exhibited improved nuclease resistance and RNA hybridizing selective ability relative to 2'-F⁻araU. In particular, when 2'-F,4'-C-OMe⁻araU inserted into C⁻H⋯F⁻C bonding-favorable 5'⁻uridine⁻purine⁻3' steps, the modified oligonucleotide showed remarkable binding affinity and selectivity to RNA complements. Thus, 2'-F, ...[more]

PMID: 30227644

Similar Datasets

Chemical Diversity of Locked Nucleic Acid-Modified Antisense Oligonucleotides Allows Optimization of Pharmaceutical Properties.

Project description:The identification of molecules that can modulate RNA or protein function and the subsequent chemical and structural optimization to refine such molecules into drugs is a key activity in drug discovery. Here, we explored the extent to which chemical and structural differences in antisense oligonucleotides, designed as gapmers and capable of recruiting RNase H for target RNA cleavage, can affect their functional properties. To facilitate structure-activity learning, we analyzed two sets of iso-sequential locked nucleic acid (LNA)-modified gapmers, where we systematically varied the number and positions of LNA modifications in the flanks. In total, we evaluated 768 different and architecturally diverse gapmers in HeLa cells for target knockdown activity and cytotoxic potential and found widespread differences in both of these properties. Binding affinity between gapmer and RNA target, as well as the presence of certain short sequence motifs in the gap region, can explain these differences, and we propose statistical and machine-learning models that can be used to predict region-specific, optimal LNA-modification architectures. Once accessible regions in the target of interest have been identified, our results show how to refine and optimize LNA gapmers with improved pharmacological profiles targeting such regions.

| S-EPMC6965521 | biostudies-literature

Knockdown of circular RNAs using LNA-modified antisense oligonucleotides

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

Synthesis and biophysical properties of carbamate-locked nucleic acid (LNA) oligonucleotides with potential antisense applications.

Project description:Antisense oligonucleotides (ASOs) are becoming important drugs for hard to treat diseases. Modifications to their DNA backbones are essential to inhibit degradation in vivo, but they can reduce binding affinity to RNA targets. To address this problem we have combined the enzymatic resistance of carbamate (CBM) DNA backbone analogues with the thermodynamic stability conferred by locked nucleic acid sugars (LNA). Using a dinucleotide phosphoramidite strategy and automated solid phase synthesis, we have synthesised a set of oligonucleotides modified with multiple LNA-CBM units. The LNA sugars restore binding affinity to RNA targets, and in this respect LNA position with respect to the CBM linkage is important. Oligonucleotides containing carbamate flanked on its 5'and 3'-sides by LNA form stable duplexes with RNA and unstable duplexes with DNA, which is desirable for antisense applications. Carbamate-LNA modified oligonucleotides also show increased stability in the presence of snake venom and foetal bovine serum compared to LNA or CBM backbones alone.

| S-EPMC6686644 | biostudies-literature

Synthesis, biophysical properties and biological activity of second generation antisense oligonucleotides containing chiral phosphorothioate linkages.

Project description:Bicyclic oxazaphospholidine monomers were used to prepare a series of phosphorothioate (PS)-modified gapmer antisense oligonucleotides (ASOs) with control of the chirality of each of the PS linkages within the 10-base gap. The stereoselectivity was determined to be 98% for each coupling. The objective of this work was to study how PS chirality influences biophysical and biological properties of the ASO including binding affinity (Tm), nuclease stability, activity in vitro and in vivo, RNase H activation and cleavage patterns (both human and E. coli) in a gapmer context. Compounds that had nine or more Sp-linkages in the gap were found to be poorly active in vitro, while compounds with uniform Rp-gaps exhibited activity very similar to that of the stereo-random parent ASOs. Conversely, when tested in vivo, the full Rp-gap compound was found to be quickly metabolized resulting in low activity. A total of 31 ASOs were prepared with control of the PS chirally of each linkage within the gap in an attempt to identify favorable Rp/Sp positions. We conclude that a mix of Rp and Sp is required to achieve a balance between good activity and nuclease stability.

| S-EPMC4267618 | biostudies-literature

Automated synthesis of new ferrocenyl-modified oligonucleotides: study of their properties in solution.

Project description:We have developed new ferrocenyl-modified oligonucleotide (ODN) probes for electrochemical DNA sensors. A monofunctional ferrocene containing phosphoramidite group has been prepared, and a new bisfunctional ferrocene containing phosphoramidite and dimethoxytrityl (DMT) groups has been developed. These ferrocenyl-phosphoramidites have been directly employed in an automated solid-phase DNA synthesizer using phosphoramidite chemistry. The advantages of this method are that it allows a non-specialist in nucleotide chemistry to access labeled ODNs and that it has demonstrated good results. ODNs modified at the 3' and/or 5' extremities have been prepared, with the incorporation of the ferrocenyl group into the chain. The 5' position appears to be more important due to its particular behavior. The thermal stability and electrochemical properties of these new ODN ferrocenes were analyzed before and after hybridization with different ODNs. The feasibility of using these new ferrocenyl-labeled ODNs in DNA sensors has been demonstrated.

| S-EPMC521675 | biostudies-literature

Gene Regulation Using Nanodiscs Modified with HIF-1-α Antisense Oligonucleotides.

Project description:Delivery of nucleic acids can be hindered by multiple factors including nuclease susceptibility, endosome trapping, and clearance. Multiple nanotechnology scaffolds have offered promising solutions, and among these, lipid-based systems are advantageous because of their high biocompatibility and low toxicity. However, many lipid nanoparticle systems still have issues regarding stability, rapid clearance, and cargo leakage. Herein, we demonstrate the use of a synthetic nanodisc (ND) scaffold functionalized with an anti-HIF-1-α antisense oligonucleotide (ASO) to reduce HIF-1-α mRNA transcript levels. We prepared ND conjugates by using a mixture of phosphoglycerolipids with phosphocholine and phosphothioethanol headgroups that self-assemble into a ∼13 × 5 nm discoidal structure upon addition of a 22-amino-acid ApoA1 mimetic peptide. Optimized reaction conditions yield 15 copies of the anti-HIF-1-α ASO DNA covalently conjugated to the thiolated phospholipids using maleimide-thiol chemistry. We show that DNA-ND conjugates are active, nuclease resistant, and rapidly internalized into cells to regulate HIF-1-α mRNA levels without the use of transfection agents. DNA-ND uptake is partially mediated through Scavenger Receptor B1 and the ND conjugates show enhanced knockdown of HIF-1-α compared to that of the soluble ASOs in multiple cell lines. Our results demonstrate that covalently functionalized NDs may offer an improved platform for ASO therapeutics.

| S-EPMC9884500 | biostudies-literature

Sequence motifs associated with hepatotoxicity of locked nucleic acid--modified antisense oligonucleotides.

Project description:Fully phosphorothioate antisense oligonucleotides (ASOs) with locked nucleic acids (LNAs) improve target affinity, RNase H activation and stability. LNA modified ASOs can cause hepatotoxicity, and this risk is currently not fully understood. In vitro cytotoxicity screens have not been reliable predictors of hepatic toxicity in non-clinical testing; however, mice are considered to be a sensitive test species. To better understand the relationship between nucleotide sequence and hepatotoxicity, a structure-toxicity analysis was performed using results from 2 week repeated-dose-tolerability studies in mice administered LNA-modified ASOs. ASOs targeting human Apolipoprotien C3 (Apoc3), CREB (cAMP Response Element Binding Protein) Regulated Transcription Coactivator 2 (Crtc2) or Glucocorticoid Receptor (GR, NR3C1) were classified based upon the presence or absence of hepatotoxicity in mice. From these data, a random-decision forest-classification model generated from nucleotide sequence descriptors identified two trinucleotide motifs (TCC and TGC) that were present only in hepatotoxic sequences. We found that motif containing sequences were more likely to bind to hepatocellular proteins in vitro and increased P53 and NRF2 stress pathway activity in vivo. These results suggest in silico approaches can be utilized to establish structure-toxicity relationships of LNA-modified ASOs and decrease the likelihood of hepatotoxicity in preclinical testing.

| S-EPMC4005641 | biostudies-literature

Ribonuclease H1-dependent hepatotoxicity caused by locked nucleic acid-modified gapmer antisense oligonucleotides.

Project description:Gapmer antisense oligonucleotides cleave target RNA effectively in vivo, and is considered as promising therapeutics. Especially, gapmers modified with locked nucleic acid (LNA) shows potent knockdown activity; however, they also cause hepatotoxic side effects. For developing safe and effective gapmer drugs, a deeper understanding of the mechanisms of hepatotoxicity is required. Here, we investigated the cause of hepatotoxicity derived from LNA-modified gapmers. Chemical modification of gapmer's gap region completely suppressed both knockdown activity and hepatotoxicity, indicating that the root cause of hepatotoxicity is related to intracellular gapmer activity. Gene silencing of hepatic ribonuclease H1 (RNaseH1), which catalyses gapmer-mediated RNA knockdown, strongly supressed hepatotoxic effects. Small interfering RNA (siRNA)-mediated knockdown of a target mRNA did not result in any hepatotoxic effects, while the gapmer targeting the same position on mRNA as does the siRNA showed acute toxicity. Microarray analysis revealed that several pre-mRNAs containing a sequence similar to the gapmer target were also knocked down. These results suggest that hepatotoxicity of LNA gapmer is caused by RNAseH1 activity, presumably because of off-target cleavage of RNAs inside nuclei.

| S-EPMC4961955 | biostudies-literature

A Tandem Oligonucleotide Approach for SNP-Selective RNA Degradation Using Modified Antisense Oligonucleotides.

Project description:Antisense oligonucleotides have been studied for many years as a tool for gene silencing. One of the most difficult cases of selective RNA silencing involves the alleles of single nucleotide polymorphisms, in which the allele sequence is differentiated by a single nucleotide. A new approach to improve the performance of allele selectivity for antisense oligonucleotides is proposed. It is based on the simultaneous application of two oligonucleotides. One is complementary to the mutated form of the targeted RNA and is able to activate RNase H to cleave the RNA. The other oligonucleotide, which is complementary to the wild type allele of the targeted RNA, is able to inhibit RNase H cleavage. Five types of SNPs, C/G, G/C, G/A, A/G, and C/U, were analyzed within the sequence context of genes associated with neurodegenerative disorders such as Alzheimer's disease, Parkinson's disease, ALS (Amyotrophic Lateral Sclerosis), and Machado-Joseph disease. For most analyzed cases, the application of the tandem approach increased allele-selective RNA degradation 1.5-15 fold relative to the use of a single antisense oligonucleotide. The presented study proves that differentiation between single substitution is highly dependent on the nature of the SNP and surrounding nucleotides. These variables are crucial for determining the proper length of the inhibitor antisense oligonucleotide. In the tandem approach, the comparison of thermodynamic stability of the favorable duplexes WT RNA-inhibitor and Mut RNA-gapmer with the other possible duplexes allows for the evaluation of chances for the allele-selective degradation of RNA. A larger difference in thermodynamic stability between favorable duplexes and those that could possibly form, usually results in the better allele selectivity of RNA degradation.

| S-EPMC4704561 | biostudies-literature

2'-O-methyl-modified phosphorothioate antisense oligonucleotides have reduced non-specific effects in vitro.

Project description:Antisense oligodeoxynucleotides (ODNs) have biological activity in treating various forms of cancer. The antisense effects of two types of 20mer ODNs, phosphorothioate-modified ODNs (S-ODNs) and S-ODNs with 12 2'-O-methyl groups (Me-S-ODNs), targeted to sites 109 and 277 of bcl-2 mRNA, were compared. Both types were at least as effective as G3139 (Genta, Inc.) in reducing the level of Bcl-2 protein in T24 cells following a 4 h transfection at a dose of 0.1 micro M. Circular dichroism spectra showed that both types formed A-form duplexes with the complementary RNA, and the melting temperatures were in the order of Me-S-ODN.RNA > normal DNA.RNA > S-ODN.RNA. In comparison with the S-ODN, the Me-S-ODN had reduced toxic growth inhibitory effects, was less prone to bind the DNA-binding domain A of human replication protein A, and was as resistant to serum nucleases. Neither type of oligomer induced apoptosis, according to a PARP-cleavage assay. Hybrids formed with Me-S-ODN sequences were less sensitive to RNase H degradation than those formed with S-ODN sequences. Despite this latter disadvantage, the addition of 2'-O-methyl groups to a phosphorothioate-modified ODN is advantageous because of increased stability of binding and reduced non-specific effects.

| S-EPMC390367 | biostudies-literature