Modified sd-rxRNA Molecules for Enhanced Cellular Uptake and Stability
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Solution Overview
Problem
Conventional oligonucleotide molecules, such as RNAi compounds, face challenges in achieving efficient gene silencing in vivo due to difficulties in cellular uptake and stability, particularly in biological fluids, limiting their clinical applicability for treating skin disorders and other conditions.
Innovation Solution
Development of chemically modified double-stranded nucleic acid molecules, including sd-rxRNAs with a combination of phosphorothioate modifications and hydrophobic conjugates, which are designed for improved cellular uptake and stability, allowing for self-delivery and efficient gene silencing, even in the presence of serum.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional double-stranded RNAi compounds are used, then gene silencing capability is achieved, but cellular uptake is limited due to rigid helix structure and negative charge
Solution Approach 1:
The patent applies parameter changes by modifying the physical and chemical properties of the RNAi compound. Specifically, it reduces the length of the double-stranded region from the conventional 19-29 bases to 8-15 bases, and introduces phosphorothioate modifications to the single-stranded region. These parameter changes transform the rigid, highly negatively-charged helix into a more flexible molecule with improved cellular uptake properties while maintaining gene silencing capability.
Solution Approach 2:
The patent creates a composite molecular structure by combining a short double-stranded region (8-15 bases) with a chemically modified single-stranded region containing phosphorothioate modifications. This composite structure integrates the gene silencing function of dsRNA with the cellular penetration properties of modified oligonucleotides, resolving the contradiction between maintaining efficacy and improving delivery.
2Reliability
If oligonucleotide molecules are administered in vivo, then gene silencing is achieved, but stability in biological fluids is poor leading to limited efficacy
Solution Approach 1:
The patent applies parameter changes by introducing phosphorothioate modifications to the single-stranded region of the nucleic acid molecule. This chemical modification increases resistance to nucleases in biological fluids, thereby improving stability and half-life in vivo without compromising the gene silencing mechanism. The modified backbone reduces degradation while maintaining the molecule's ability to bind and silence target mRNA.
3Ease of operation
If chemically modified oligonucleotides with cholesterol conjugates are used, then cellular uptake is improved, but uptake is inhibited in the presence of biological fluids
Solution Approach 1:
The patent applies the extraction principle by removing the cholesterol conjugate delivery system that caused inhibition in biological fluids. Instead of using external delivery vehicles, the invention creates a self-delivering molecule through internal structural modifications (phosphorothioate modifications and reduced dsRNA length). This extracts the problematic delivery component while retaining the essential cellular uptake enhancement through chemical modification.
Solution Approach 2:
The patent implements self-service by designing a nucleic acid molecule that delivers itself without requiring external delivery vehicles like cholesterol conjugates. The phosphorothioate modified single-stranded region provides inherent cellular penetration capability, allowing the molecule to self-deliver its gene silencing function even in the presence of biological fluids, eliminating the contradiction between uptake enhancement and fluid compatibility.
Data Source
AI summary
The present invention relates to RNAi constructs with improved tissue and cellular uptake characteristics and methods of use of these compounds in dermal applications.