Gamma-Sarcoglycan Exon Skipping for Reading Frame Restoration
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Solution Overview
Problem
Current treatments for Limb-Girdle Muscular Dystrophy type 2C (LGMD2C) are inadequate in restoring the reading frame of the gamma sarcoglycan gene, leading to the absence of functional γ-sarcoglycan protein and associated muscle degeneration.
Innovation Solution
The use of antisense polynucleotides, including modified oligonucleotides and conjugates, to induce exon skipping in the γ-sarcoglycan gene, specifically targeting exons 4, 5, and 6, to produce a truncated Mini-Gamma protein that can interact with the sarcoglycan complex and stabilize muscle cells.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional treatments are used for LGMD2C, then the reading frame of the gamma sarcoglycan gene cannot be restored, but using exon skipping with antisense polynucleotides can restore the reading frame and produce functional protein
Solution Approach 1:
The patent uses antisense polynucleotides as intermediary molecules that bind to specific exon sequences in the gamma sarcoglycan pre-mRNA, inducing exon skipping. This mediator approach allows restoration of the reading frame by excluding specific exons (4, 5, or 6) containing pathogenic variants, thereby producing a functional mini-sarcoglycan protein without directly modifying the genomic DNA
Solution Approach 2:
The invention changes the splicing parameters of the gamma sarcoglycan gene by using chemically modified oligonucleotides (such as 2'-O-methyl, 2'-O-methoxyethyl, phosphorodiamidate morpholino) that alter the splicing machinery's behavior. These parameter changes in oligonucleotide chemistry enable selective exon skipping and restoration of the reading frame that conventional treatments cannot achieve
2Reliability
If exon skipping is induced to restore reading frame, then functional Mini-Gamma protein is produced, but the treatment requires multiple distinct antisense oligonucleotides targeting different exons
Solution Approach 1:
The patent divides the treatment into multiple segmented antisense oligonucleotides, each targeting a specific exon (exon 4, 5, or 6) containing pathogenic variants. This segmentation allows selective induction of exon skipping at specific locations in the pre-mRNA, enabling restoration of the reading frame while maintaining flexibility in treating different mutation types. Each oligonucleotide segment can be independently designed and optimized for its target exon
Solution Approach 2:
The invention creates a universal treatment platform using a family of antisense oligonucleotides with similar chemical structures and mechanisms of action. These oligonucleotides can be applied across different LGMD2C patients with various mutations in exons 4, 5, or 6, providing a multi-functional solution that addresses diverse genetic defects with a unified therapeutic approach based on exon skipping
3Reliability
If antisense polynucleotides are used to induce exon skipping, then muscle function is improved, but the oligonucleotides may be degraded by cellular nucleases
Solution Approach 1:
The patent employs chemically composite oligonucleotide structures combining multiple modified components: modified sugar moieties (2'-O-methyl, 2'-O-methoxyethyl), modified phosphate linkages (phosphorodiamidate, phosphorothioate), and morpholino rings. These composite material modifications confer resistance to cellular nucleases while maintaining the ability to bind target RNA and induce exon skipping, thereby improving both stability and therapeutic efficacy in muscle tissue
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 exon skipping strategy effectively restores muscle function by enhancing the expression of a functional Mini-Gamma protein, improving muscle strength, stability, and cardiac function in LGMD2C patients.
Implementation Method 1
The use of antisense polynucleotides, including modified oligonucleotides and conjugates, to induce exon skipping in the γ-sarcoglycan gene
Data Source
AI summary
The invention is directed to one or more antisense polynucleotides and their use in pharmaceutical compositions in a strategy to induce exon skipping in the γ-sarcoglycan gene in patients suffering from Limb-Girdle Muscular Dystrophy-2C (LGM-D2C) or in patients at risk of such a disease. The invention also provides methods of preventing or treating muscular dystrophy, e.g., LGMD2C, by exon skipping in the gamma sarcoglycan gene using antisense polynucleotides. Accordingly, in some aspects the invention provides an isolated antisense oligonucleotide, wherein the oligonucleotide specifically hybridizes to an exon target region of a γ-sarcoglycan RNA. In another aspect, the the invention provides a method of inducing exon-skipping of a gamma sarcoglycan RNA, comprising delivering an antisense oligonucleotide or a composition to a cell.