Segmented Antisense Oligonucleotides for DMPK RNA Reduction
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Solution Overview
Problem
Current treatments do not effectively modify the course of myotonic dystrophy type 1 (DM1), a severe autosomal dominant disorder characterized by muscle wasting, myotonia, and other systemic symptoms, primarily due to the expansion of a CTG repeat in the DMPK gene leading to RNA dominance and cellular dysfunction.
Innovation Solution
The use of modified oligonucleotides, specifically antisense oligonucleotides, targeted to DMPK to inhibit the expression of DMPK mRNA and protein, thereby reducing the toxicity associated with CUGexp DMPK RNA and alleviating symptoms of DM1.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If antisense oligonucleotides are administered to reduce DMPK expression, then DMPK mRNA and protein levels are reduced, but the complexity of the treatment and potential off-target effects increase
Solution Approach 1:
The oligonucleotide is divided into distinct functional segments: a 5' wing region with modified nucleosides for stability and binding, a central gap region with unmodified deoxynucleosides for RNase H recruitment, and a 3' wing region with modified nucleosides. This segmentation allows each region to contribute specific functions while reducing off-target effects.
Solution Approach 2:
Different regions of the oligonucleotide have different chemical modifications tailored to their specific functions. The 5' and 3' wings contain modified nucleosides (such as 2'-O-methoxyethyl or LNA) for enhanced binding affinity and stability, while the central gap contains unmodified deoxynucleosides to facilitate RNase H cleavage. This local differentiation optimizes both efficacy and safety.
2Duration of action of stationary object
If fully modified oligonucleotides are used to enhance stability and binding, then nuclease resistance increases, but RNase H cleavage efficiency decreases
Solution Approach 1:
The oligonucleotide is segmented into modified regions (5' and 3' wings) for nuclease resistance and an unmodified central gap region for RNase H cleavage. This segmentation resolves the contradiction by localizing different chemical properties to different regions.
Solution Approach 2:
The central gap region contains unmodified deoxynucleosides that maintain natural DNA structure and conformation, enabling efficient recognition and cleavage by RNase H. The modified wings provide stability without interfering with the cleavage mechanism in the gap region.
3Measurement precision
If oligonucleotides are designed to specifically target CUGexp DMPK RNA, then selectivity increases, but the risk of spliceopathy and off-target effects remains
Solution Approach 1:
The invention extracts and targets specifically the expanded CUG repeat region in the 3' UTR of DMPK mRNA, which is present only in mutant transcripts. By focusing on this unique sequence feature, the oligonucleotide achieves high selectivity for CUGexp DMPK RNA while minimizing effects on wild-type transcripts and other genes.
Solution Approach 2:
RNase H acts as an intermediary enzyme that recognizes the DNA-RNA hybrid formed by the oligonucleotide binding to CUGexp DMPK RNA and catalyzes its cleavage. This enzymatic mediation provides sequence-specific degradation while limiting off-target effects to regions with high sequence homology.
4Reliability
If high doses of oligonucleotides are administered to achieve sufficient DMPK reduction, then therapeutic effect increases, but toxicity and immunogenicity increase
Solution Approach 1:
The oligonucleotide incorporates modified nucleosides that change key parameters: enhanced binding affinity (lowering the dose required for effective target engagement), increased nuclease resistance (prolonging half-life and reducing dosing frequency), and improved cellular uptake. These parameter changes allow effective therapy at lower doses, reducing toxicity and immunogenicity.
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 administration of these modified oligonucleotides effectively reduces DMPK expression, preferentially targeting CUGexp DMPK RNA, which in turn decreases myotonia and spliceopathy, offering a potential therapeutic approach to treat, prevent, or ameliorate DM1 symptoms.
Implementation Method 1
administering to the subject a compound according to any of embodiments 1 to 130, or a composition according to embodiment 132; wherein said compound, when bound to said CUGexp DMPK RNA, activates a ribonuclease
Implementation Method 2
said compound, when bound to said CUGexp DMPK RNA, activates a ribonuclease, thereby achieving a preferential reduction of said CUGexp DMPK RNA
Data Source
AI summary
Provided herein are methods, compounds, and compositions for reducing expression of a DMPK mRNA and protein in an animal. Also provided herein are methods, compounds, and compositions for preferentially reducing CUGexp DMPK RNA, reducing myotonia or reducing spliceopathy in an animal. Such methods, compounds, and compositions are useful to treat, prevent, delay, or ameliorate type 1 myotonic dystrophy, or a symptom thereof.