MSH3-Targeting siRNA Compositions for Microsatellite Repeat Control
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Solution Overview
Problem
Current treatments for diseases caused by pathological microsatellite DNA expansions, such as Huntington's Disease and myotonic dystrophy type 1, lack the ability to selectively diminish MutS Homolog 3 (MSH3) activity effectively, which is crucial for disease progression.
Innovation Solution
The use of small interfering RNA (siRNA) molecules to silence MSH3 transcripts, reducing MSH3 protein expression and preventing disease onset or progression by delivering the siRNA molecules to target tissues through various injection methods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional treatments are used for Huntington's Disease and myotonic dystrophy type 1, then current standard care is provided, but the ability to selectively diminish MSH3 activity is insufficient
Solution Approach 1:
The patent uses siRNA molecules as intermediary substances that specifically bind to and silence MSH3 mRNA transcripts. These siRNA molecules act as mediators between the therapeutic goal (reducing MSH3 activity) and the molecular target (MSH3 gene expression), enabling selective diminishment of MSH3 activity without affecting other genes or proteins. The siRNA molecules incorporate chemically modified nucleotides and backbone structures to enhance stability and specificity while reducing off-target effects.
Solution Approach 2:
The patent employs chemical modification of the siRNA molecule parameters including nucleotide composition (2'-O-methyl, 2'-fluoro modifications), backbone structure (phosphorothioate linkages), and terminal modifications (cholesterol, phosphorothioate caps). These parameter changes enhance the selectivity, stability, and efficacy of the siRNA molecules while minimizing degradation and off-target effects, thereby resolving the contradiction between selectivity and efficacy.
2Reliability
If MSH3 activity is reduced to prevent disease progression, then therapeutic benefit is achieved, but delivery to target tissues must be optimized
Solution Approach 1:
The patent uses various delivery vehicles and methods (lipid nanoparticles, conjugates with targeting ligands, intrathecal catheters) as intermediaries to transport the siRNA molecules from administration sites to the target tissues in the central nervous system. These delivery systems mediate the complex process of getting the therapeutic agent across biological barriers (blood-brain barrier, choroid plexus) to reach the intended target cells expressing MSH3.
Solution Approach 2:
The patent modifies physical and chemical parameters of the delivery system including particle size, surface charge, lipid composition, and conjugate structure to optimize tissue penetration, cellular uptake, and release kinetics. These parameter changes enable effective delivery to specific brain regions while simplifying the overall treatment protocol by incorporating multiple functions into single administration routes.
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 siRNA-mediated silencing of MSH3 provides high selectivity and efficacy in preventing the translation of MSH3 mRNA, thereby inhibiting the lengthening of DNA microsatellite repeats to pathological lengths, thus offering a potential therapeutic approach for these diseases.
Implementation Method 1
The antisense strand has complementarity sufficient to hybridize to a region within an MSH3 mRNA transcript
Data Source
AI summary
The present disclosure provides single- or double-stranded interfering RNA molecules (e.g., siRNA) that target a MutS Homolog 3 (MSH3) gene. The interfering RNA molecules may contain specific patterns of nucleoside modifications and internucleoside linkage modifications, as pharmaceutical compositions including the same. The siRNA molecules may be branched siRNA molecules, such as di-branched, tri-branched, or tetra-branched siRNA molecules. The disclosed siRNA molecules may further feature a 5′ phosphorus stabilizing moiety and/or a hydrophobic moiety. Additionally, the disclosure provides methods for delivering the siRNA molecule of the disclosure to the central nervous system of a subject, such as a subject identified as having Huntington's Disease.