Modified mRNA Nucleotide Composition for Protein Expression
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Solution Overview
Problem
Current mRNA-based therapies for diseases caused by deficient or defective genes face challenges due to the instability and immunogenicity of mRNA, leading to insufficient protein production and frequent administration needs, along with significant immune reactions.
Innovation Solution
Development of polyribonucleotides, specifically messenger RNA (mRNA) containing a combination of unmodified and modified nucleotides, where 5% to 50% of uridine and cytidine nucleotides are modified, to enhance stability and reduce immunogenicity, allowing for efficient protein expression and prolonged duration of action.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If mRNA is used for therapy, then protein production is achieved, but mRNA instability leads to insufficient protein quantity and frequent administration
Solution Approach 1:
The patent applies parameter changes by modifying the chemical structure of nucleotides within the mRNA molecule. Specifically, it replaces a portion (5-50%) of natural nucleotides with modified nucleotides such as pseudouridine, 5-methylcytidine, 2-thiouridine, and N6-methyladenosine. This chemical parameter change enhances the mRNA's resistance to degradation by nucleases while maintaining its ability to be translated into protein, thereby simultaneously improving both stability and protein production efficiency.
Solution Approach 2:
The patent creates a composite nucleic acid structure by combining modified and unmodified nucleotides within the same mRNA molecule. This composite approach allows the mRNA to exhibit properties of both stability (from modified nucleotides) and translational efficiency (from unmodified nucleotides). The heterogeneous composition of nucleotide types within the single mRNA strand resolves the contradiction between stability and productivity.
2Productivity
If mRNA is used for therapy, then protein production is achieved, but strong immunological reactions occur
Solution Approach 1:
The patent modifies the chemical parameters of the mRNA by incorporating modified nucleotides that alter the molecule's recognition by the immune system. The modified nucleotides (pseudouridine, 5-methylcytidine, 2-thiouridine, N6-methyladenosine) change the structural and electrostatic properties of the mRNA, reducing its binding affinity to Toll-like receptors and other immune sensors. This parameter change allows the mRNA to evade immune detection while maintaining protein expression capability.
Solution Approach 2:
The patent converts the harmful immunogenicity of mRNA into a beneficial property by using modified nucleotides. The modifications that reduce immune recognition also improve mRNA stability and translational efficiency. Thus, what could be seen as a deviation from natural structure is actually converted into a therapeutic advantage, reducing side effects while enhancing protein production.
3Reliability
If modified nucleotides are used in mRNA, then immunogenicity is reduced and stability is improved, but transfection efficiency may be affected
Solution Approach 1:
The patent applies partial action by modifying only a portion (5-50%) of the nucleotides in the mRNA molecule rather than all of them. This partial modification strategy optimizes the balance between stability/imunogenicity and transfection efficiency. By not fully replacing all nucleotides, the mRNA retains sufficient natural characteristics for efficient cellular uptake and translation, while the modified portion provides the desired stability and reduced immunogenicity.
Solution Approach 2:
The patent applies local quality by strategically placing modified nucleotides at specific positions within the mRNA sequence rather than uniformly throughout. Different regions of the mRNA can have different modification densities, with modified nucleotides concentrated in regions where they provide maximum stability benefit without interfering with critical functional elements like the 5' cap, 3' poly-A tail, or coding sequence integrity. This localized modification approach preserves transfection efficiency while achieving the desired stability improvement.
Data Source
AI summary
The invention relates to a polyribonucleotide with a sequence that codes a protein or protein fragment, wherein the polyribonucleotide comprises a combination of unmodified and modified nucleotide, wherein 5 to 50% of the uridine nucleotides and 5 to 50% of the cytidin nucleotides are modified uridine nucleotides or modified cytidin nucleotides.