Segmented siRNA with 3' Overhangs for Targeted Gene Silencing

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Solution Overview

Problem

Current methods for generating siRNA are limited in their ability to effectively induce RNA interference for therapeutic applications, particularly in targeting specific genes associated with pathological conditions, as they lack efficiency and specificity in inhibiting gene expression.

Innovation Solution

The method involves synthesizing short double-stranded RNA molecules with specific nucleotide lengths and 3' overhangs, which are designed to target specific mRNA sequences, allowing for the formation of double-stranded RNA molecules with single-stranded regions that can mediate RNA interference and DNA methylation, enhancing their stability and therapeutic potential.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If current methods for generating siRNA are used, then the process is simple, but the efficiency and specificity in inhibiting gene expression is insufficient

Engineering Contradiction:
Improveefficiency and specificity in inhibiting gene expressionVSAvoidcomplexity of siRNA structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The siRNA is segmented into three distinct nucleotide strands (first, second, and third strands) with specific length ranges. The first strand is 10-25 nucleotides, the second strand is 1-10 nucleotides, and the third strand is 1-10 nucleotides. This segmentation allows each strand to perform specific functions: the first strand provides the primary targeting sequence, while the second and third strands form the 3' overhang structure that enhances stability and RNAi activity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the siRNA structure are given different properties. The 5' end region (first strand) has specific sequence identity to the target mRNA for recognition and binding. The 3' end region (second and third strands) forms a single-stranded overhang with specific length (1-10 nucleotides) that provides structural stability and enhances RNA interference activity. This local differentiation of structure and function improves both efficiency and specificity.

Inventive Principle:
Principle #3Local quality

2Productivity

If siRNA is designed with specific nucleotide lengths and 3' overhangs, then RNA interference efficiency is improved, but the manufacturing process becomes more complex

Engineering Contradiction:
ImproveRNA interference efficiencyVSAvoidease of synthesizing multi-strand RNA
Core Design Contradiction:
ProductivityVSEase of manufacture

Solution Approach 1:

The three nucleotide strands are synthesized separately with predetermined lengths and sequences before assembly. The first strand is synthesized to be 10-25 nucleotides, while the second and third strands are synthesized to be 1-10 nucleotides each. This preliminary synthesis allows for precise control over the final siRNA structure, including the formation of the 3' overhang, without requiring complex post-synthesis modifications.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The three separate nucleotide strands self-assemble through complementary base pairing to form the final double-stranded RNA structure with the characteristic 3' overhang. The second and third strands automatically pair with each other to form the overhang region, while the first strand pairs with the complementary region. This self-assembly process eliminates the need for complex enzymatic ligations or additional processing steps.

Inventive Principle:
Principle #25Self-service

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

This approach enables targeted and efficient RNA interference, effectively inhibiting the expression of genes associated with pathological conditions, such as VEGF, by forming double-stranded RNA molecules with specific nucleotide identities and 3' overhangs, demonstrating improved efficacy in reducing target mRNA levels.

Implementation Method 1

combining the synthesized RNA strands under conditions, wherein a double-stranded RNA molecule is formed

Methodology Applied
Scientific EffectComplementary base pairing: Chemical Bonding

Data Source

PatentEP2076598B1Sirna and methods of manufacture
Publication Date: 2012.05.23 OPKO PHARMACEUTICALS LLC
  • EP2076598B1 patent drawingFigure 1
  • EP2076598B1 patent drawing

AI summary

Double-stranded RNA of about 19 to about 25 nucleotides in length capable of regulating gene expression by RNA interference is provided. Such double-stranded RNA are particularly useful for treating disease or conditions associated with a target mRNA or gene. Methods of manufacture and methods of use of the double-stranded RNA are also provided.