Modified siRNA for Hepatitis B Gene Silencing
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Solution Overview
Problem
Current treatments for hepatitis B, such as interferons and nucleoside analogues, face challenges like adverse reactions, drug resistance, and disease recurrence, highlighting the need for a mechanism to silence viral gene expression and inhibit HBV replication at the gene level.
Innovation Solution
Development of a specific siRNA with modified nucleotides, comprising a sense and antisense strand designed to be partly reverse complementary, which can effectively inhibit HBV gene expression by forming a double-stranded region, and is stabilized through modifications like fluoro and methoxy substitutions, enhancing its stability and delivery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If interferons are used to treat hepatitis B, then viral gene expression can be inhibited, but adverse reactions occur
Solution Approach 1:
The patent applies parameter changes by modifying the chemical structure of nucleoside analogues through various substitutions (fluoro, methoxy, deoxy modifications at specific positions) to alter their biological properties. These structural parameter changes enable the siRNA to maintain viral inhibition effectiveness while reducing adverse reactions and drug resistance issues associated with conventional treatments
Solution Approach 2:
The patent employs composite materials by creating siRNA molecules composed of hybrid nucleotide sequences combining modified and unmodified nucleotides. This composite structure integrates the stability benefits of modified nucleotides (fluoro, methoxy groups) with the biological activity of natural nucleotides, achieving both effective viral gene silencing and reduced toxicity
2Reliability
If nucleoside analogues are used to treat hepatitis B, then viral replication can be inhibited, but drug resistance and disease recurrence occur
Solution Approach 1:
The patent applies parameter changes by systematically modifying nucleoside analogue structures with fluoro substitutions at positions 2′ and 4′, methoxy groups at position 2′, and deoxy modifications. These parameter changes create novel compounds with altered binding affinity and resistance profiles, preventing the development of drug resistance while maintaining effective viral replication inhibition
Solution Approach 2:
The patent applies local quality by introducing specific modifications at particular positions within the nucleoside structure (e.g., fluoro at 2′/4′, methoxy at 2′, deoxy at 1′) rather than uniform modification throughout. This localized modification strategy optimizes both antiviral activity and resistance prevention while minimizing off-target effects
3Reliability
If siRNA is designed to inhibit HBV gene expression, then viral replication can be blocked, but stability and delivery challenges arise
Solution Approach 1:
The patent applies parameter changes by modifying the siRNA backbone and nucleotide composition with stable chemical groups (fluoro, methoxy, deoxy modifications). These parameter changes enhance the siRNA's resistance to nucleases and improve its pharmacokinetic properties, solving stability and delivery challenges while maintaining gene silencing effectiveness
Solution Approach 2:
The patent employs intermediary strategies by using modified nucleotide sequences as mediators between the siRNA's gene silencing function and its stability requirements. The modified nucleotides act as intermediaries that protect the siRNA from degradation while allowing it to maintain its biological activity and be delivered effectively to target cells
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 effectively inhibits HBV gene expression, maintaining high stability and biological activity, thereby providing a potential treatment for hepatitis B by silencing the viral gene, addressing the limitations of existing therapies.
Implementation Method 1
the nucleotide sequence I and the nucleotide sequence II are at least partly reverse complementary to form a double-stranded region
Implementation Method 2
Stabilization modification of siRNA and its delivery system are two key technologies in the development of small RNA drugs
Data Source
AI summary
Provided are an siRNA for inhibiting expression of a Hepatitis B virus gene, and a pharmaceutical composition and conjugate containing the siRNA. Each nucleotide in the siRNA is an independently modified or unmodified nucleotide; the siRNA comprises a sense strand and an antisense strand; the sense strand comprises a nucleotide sequence A; the length of the nucleotide sequence A is the same as that of a nucleotide sequence as shown in SEQ ID NO: 1, and the number of the nucleotide differences is not more than three; the antisense strand comprises a nucleotide sequence B; and the length of the nucleotide sequence B is the same as that of a nucleotide sequence as shown in SEQ ID NO: 2, and number of nucleotide differences is not more than three.