CRISPR Epigenetic Repression of Hepatitis B Viral Genes
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Solution Overview
Problem
Current treatments for chronic Hepatitis B infection, such as nucleoside analogs, PEGylated interferon, and siRNA, face challenges in efficacy and stability, necessitating improved methods for reducing Hepatitis B viral (HBV) replication and expression.
Innovation Solution
An epigenetic-modifying DNA-targeting system using CRISPR-Cas/guide RNA (gRNA) systems to repress HBV gene transcription by binding to specific sites in the HBV DNA sequence, employing fusion proteins with DNA-binding domains and transcriptional repressor effector domains to reduce HBV replication and protein levels without causing genetic disruption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If nucleoside analogs or siRNA are used to suppress HBV transcription, then viral replication is reduced, but treatment efficacy and stability are insufficient
Solution Approach 1:
The patent employs a composite system combining CRISPR-Cas9 protein with guide RNA to create an epigenetic-modifying DNA-targeting system. This composite approach integrates two distinct molecular components (protein and nucleic acid) that work synergistically to achieve superior HBV suppression compared to single-agent therapies like nucleoside analogs or siRNA, directly addressing the insufficiency of treatment efficacy in existing approaches
Solution Approach 2:
The patent replaces the mechanical/enzymatic action of nucleoside analogs (which require cellular activation and incorporation into DNA) with a targeted epigenetic modification system. The CRISPR-Cas9 system directly binds to HBV DNA and recruits epigenetic modifiers to alter chromatin structure and gene expression, substituting a more direct and controllable mechanism that improves both efficacy and stability
2Reliability
If PEGylated interferon or anti-sense oligonucleotide is administered, then HBV expression is suppressed, but stability and efficacy face challenges
Solution Approach 1:
The patent designs a system where the CRISPR-Cas9 complex, once bound to HBV DNA, establishes continuous epigenetic repression through recruitment of modifying enzymes. This creates a sustained therapeutic effect that overcomes the stability issues of PEGylated interferon (which has limited half-life) and anti-sense oligonucleotides (which may be degraded or displaced), ensuring continuous viral expression suppression
Solution Approach 2:
The patent introduces epigenetic modifiers as intermediary molecules that mediate between the CRISPR-Cas9 binding event and the final suppression of viral expression. These intermediaries (histone modifiers, DNA methyltransferases) provide a stable and amplifiable mechanism for gene repression, addressing the stability and efficacy challenges of direct-acting agents like interferon and anti-sense oligonucleotides
3Reliability
If CRISPR-Cas/guide RNA system is used to repress HBV transcription, then treatment efficacy is enhanced, but system complexity increases
Solution Approach 1:
The patent designs the CRISPR-Cas9 system with multi-functionality: the same Cas9 protein and guide RNA complex serves both for targeted DNA binding and for recruiting multiple types of epigenetic modifiers. This universal platform approach reduces the need for separate specialized components for each function, thereby managing system complexity while maintaining enhanced treatment efficacy
Solution Approach 2:
The patent merges the DNA-targeting function (CRISPR-Cas9) with the epigenetic modification function into a single integrated system. By combining these functions in one complex rather than using separate systems, the patent reduces overall system complexity while achieving superior efficacy compared to sequential or separate therapeutic approaches
4Productivity
If multiple DNA-targeting modules are employed to target multiple HBV sites, then viral replication reduction is improved, but manufacturing and delivery complexity increases
Solution Approach 1:
The patent segments the HBV genome into multiple target sites, each addressed by a specific guide RNA sequence. This segmentation allows the system to tackle different regions of the viral genome independently, improving overall viral replication reduction. The modular nature of guide RNAs makes them relatively easy to manufacture and customize compared to larger molecular complexes
Solution Approach 2:
The patent uses a universal CRISPR-Cas9 protein component that can work with multiple different guide RNAs targeting different HBV sites. This universality simplifies manufacturing by requiring production of only one protein variant (Cas9) that can be paired with various guide RNAs, thereby improving ease of manufacture while achieving multi-site viral replication suppression
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 system effectively reduces HBV replication and protein levels by targeting multiple sites in the HBV genome, enhancing treatment efficacy and stability compared to existing therapies.
Implementation Method 1
a Clustered Regularly Interspaced Short Palindromic Repeats associated (Cas)-guide RNA (gRNA) combination comprising (a) a Cas protein or a variant thereof and (b) at least one gRNA
Implementation Method 2
epigenetic-modifying DNA-targeting system comprising at least one DNA-targeting module for repressing transcription of one or more Hepatitis B viral (HBV) genes
Data Source
AI summary
Provided herein are epigenetic-modifying DNA-targeting systems, such as CRISPR-Cas/guide RNA (gRNA) systems, for the transcriptional repression of Hepatitis B viral (HBV) genes to promote a cellular phenotype that leads to the reduction of HBV infection. In some embodiments, the epigenetic-modifying DNA-targeting systems bind to or target a target site of at least one gene or regulatory element thereof in a Hepatitis B viral DNA sequence in cell. In some aspects, the provided systems relate to the transcriptional repression of one or more Hepatitis B viral gene and/or regulatory element thereof. In some aspects, also provided herein are methods and uses related to the provided compositions, for example in repressing Hepatitis B viral replication and expression in connection with Hepatitis B infections.