Antisense Oligonucleotides for Stable MicroRNA Silencing
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Solution Overview
Problem
Current oligonucleotide approaches for inhibiting microRNAs, such as those using LNA-modified oligonucleotides, face challenges including low in vivo stability, inefficient uptake, and high dosages required for effective silencing, which limits their therapeutic potential for diseases associated with microRNA dysregulation.
Innovation Solution
Designing short oligonucleotides with high affinity nucleotide analogues like LNA, 2'-MOE RNA, or 2'-Fluoro nucleotides, specifically targeting the seed sequence of microRNAs to form stable and non-functional duplexes, thereby reducing microRNA repression without significant off-target effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If LNA-modified oligonucleotides are used to inhibit microRNAs, then silencing efficacy is improved, but in vivo stability deteriorates
Solution Approach 1:
The patent modifies the chemical parameters of the oligonucleotide by incorporating specific nucleotide analogues (2'-O-methyl RNA, 2'-fluoro DNA) in defined patterns within the LNA-modified sequence. This changes the binding affinity and stability parameters to achieve optimal silencing efficacy while improving in vivo stability compared to fully LNA-modified oligonucleotides.
Solution Approach 2:
The oligonucleotide employs a composite structure combining different nucleotide types (DNA, RNA, LNA, 2'-O-methyl RNA, 2'-fluoro DNA) in a single sequence. This composite approach allows each component to contribute specific properties: LNA provides high affinity binding, while 2'-O-methyl and 2'-fluoro modifications enhance stability and reduce immunogenicity, resolving the contradiction between efficacy and stability.
2Productivity
If high dosages of oligonucleotides are administered, then silencing efficacy is improved, but toxicity increases
Solution Approach 1:
The patent optimizes the dosage parameter by demonstrating that the modified oligonucleotide sequence achieves effective silencing at lower concentrations (e.g., 1-10 mg/kg) compared to conventional oligonucleotides. The enhanced binding affinity per molecule allows reduced dosing, thereby improving the efficacy-toxicity ratio.
3Duration of action of stationary object
If short oligonucleotides with high affinity nucleotide analogues are designed, then silencing duration is improved, but manufacturing complexity increases
Solution Approach 1:
The patent extends the duration of action by designing oligonucleotides with increased binding affinity through strategic LNA and 2'-fluoro modifications. The shorter sequence (15-25 nucleotides) with high-affinity modifications provides prolonged silencing duration while simplifying the overall molecular structure compared to longer conventional oligonucleotides, thereby managing manufacturing complexity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The proposed solution achieves efficient and long-lasting silencing of microRNAs with reduced dosages, enhancing therapeutic efficacy while minimizing toxicity and off-target effects, as demonstrated by the oligonucleotide sequence 5'-CcAttGTcaCaCtCC, which forms a stable duplex with microRNA targets, effectively reducing their functional levels in vivo.
Implementation Method 1
MicroRNAs (miRNAs) are an abundant class of short endogenous RNAs that act as post-transcriptional regulators of gene expression by base-pairing with their target mRNAs
Data Source
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AI summary
The invention provides pharmaceutical compositions comprising short single stranded oligonucleotides, of length of between 8 and 26 nucleobases which are complementary to human microRNAs selected from the group consisting of miR19b, miR21, miR122a, miR155 and miR375. The short oligonucleotides are particularly effective at alleviating miRNA repression in vivo. It is found that the incorporation of high affinity nucleotide analogues into the oligonucleotides results in highly effective anti-microRNA molecules which appear to function via the formation of almost irreversible duplexes with the miRNA target, rather than RNA cleavage based mechanisms, such as mechanisms associated with RNaseH or RISC.