Codon-Optimized Factor VIII Gene Therapy Vector Design
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Solution Overview
Problem
Current treatments for hemophilia A, such as Factor VIII replacement therapy, are costly, require continuous administration, and often lead to the formation of anti-Factor VIII inhibitor antibodies, reducing therapy efficacy.
Innovation Solution
Development of codon-altered nucleic acids encoding Factor VIII variants that can be efficiently packaged and delivered via gene therapy vectors, including a polynucleotide encoding a Factor VIII polypeptide with a high sequence identity to CS04-HC-NA and CS04-LC-NA, and a linker sequence replacing the native B-domain with a furin cleavage site.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If Factor VIII replacement therapy is administered continuously to maintain adequate Factor VIII activity levels, then bleeding episodes are prevented and coagulation is maintained, but treatment cost increases and patient compliance burden increases
Solution Approach 1:
The Factor VIII protein is divided into two separate chains (heavy chain and light chain) that are encoded by distinct nucleic acid sequences. These separate chains are expressed independently and then assemble to form the functional Factor VIII heterodimer, allowing for more efficient viral vector packaging and sustained expression
Solution Approach 2:
The nucleic acid sequences are codon-optimized to match host cell preferences, and the protein structure is modified by separating the heavy and light chains. These parameter changes in sequence composition and structural organization enable improved expression levels and sustained Factor VIII activity with less frequent administration
2Reliability
If conventional nucleic acid sequences encoding Factor VIII are used in gene therapy vectors, then the therapy can be administered, but packaging efficiency is poor and expression levels are insufficient
Solution Approach 1:
The coding sequence for Factor VIII is split into two separate nucleic acid sequences: one encoding the heavy chain and another encoding the light chain. This segmentation reduces the size of individual transgenes, improving packaging efficiency in viral vectors while maintaining the ability to produce functional Factor VIII through in vivo assembly of the heterodimer
Solution Approach 2:
A linker sequence serves as an intermediary element connecting the heavy chain and light chain coding regions. This linker facilitates proper spatial arrangement and interaction between the two chains during translation and assembly, ensuring correct Factor VIII heterodimer formation while allowing independent expression from separate nucleic acid sequences
3Reliability
If Factor VIII replacement therapy is used, then hemophilia A symptoms are treated, but anti-Factor VIII inhibitor antibodies are formed that reduce therapy efficacy
Solution Approach 1:
The Factor VIII protein structure is modified by separating it into heavy and light chains and optimizing the codon usage of the encoding nucleic acids. These parameter changes produce a recombinant Factor VIII variant that may have reduced immunogenicity while maintaining coagulant activity, potentially decreasing inhibitor antibody formation
Solution Approach 2:
Instead of administering native Factor VIII protein, the invention uses genetically engineered copies of the Factor VIII coding sequence that are codon-optimized and divided into separate chains. These modified copies are expressed in host cells and assembled into functional protein, providing a alternative form that may evade the immune system's recognition of native Factor VIII
Data Source
AI summary
The present disclosure provides, among other aspects, codon-altered polynucleotides encoding Factor VIII variants for expression in mammalian cells. In some embodiments, the disclosure also provides mammalian gene therapy vectors and methods for treating hemophilia A. In some embodiments, the present disclosure provides methods for dosing a hemophilia A patient with a polynucleotide, e.g., a codon-altered polynucleotide, encoding a Factor VII polypeptide.