Circular RNA Urate Oxidase Expression Low Immunogenicity
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Solution Overview
Problem
Current treatments for hyperuricemia, such as xanthine oxidase inhibitors and uric acid excretion-promoting drugs, are associated with immunogenicity and kidney burden, and existing urate oxidase preparations derived from foreign proteins can cause allergic reactions, necessitating the development of molecules with high activity and low immunogenicity for effective uric acid reduction.
Innovation Solution
A recombinant nucleic acid molecule is designed to express urate oxidase using a circular RNA construct that includes an intron fragment, an E2 fragment, an internal ribosome entry site, a urate oxidase coding fragment, and an E1 fragment, with optional signal peptides for secretion and peroxisome positioning, derived from animal sequences, to produce a stable and immunologically benign urate oxidase enzyme.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If foreign protein-derived urate oxidase is used, then uric acid reduction activity is achieved, but immunogenicity and allergic reactions occur
Solution Approach 1:
The patent changes the source parameter of urate oxidase from foreign proteins (Aspergillus niger, Aspergillus flavus) to animal proteins (pig, baboon, cow), which fundamentally alters the immunogenicity parameter while maintaining enzymatic activity. This parameter change resolves the contradiction by selecting a protein source that is evolutionarily closer to humans, reducing immunogenicity while preserving function.
Solution Approach 2:
The patent creates a recombinant urate oxidase by copying the gene sequence from animal sources (pig, baboon, or cow) into a expression vector system. This allows production of the enzyme in a controlled manner using animal-derived sequences that are more compatible with human immune systems, thereby reducing immunogenicity while maintaining the required catalytic activity.
2Reliability
If xanthine oxidase inhibitors are used, then uric acid production is reduced, but kidney burden increases
Solution Approach 1:
The patent extracts and utilizes the endogenous urate oxidase enzyme system from animal sources, which naturally converts uric acid to allantoin in the liver. This approach shifts the metabolic pathway from inhibition (xanthine oxidase inhibitors) to direct conversion via urate oxidase, reducing kidney burden by avoiding the accumulation of uric acid precursors that requires renal excretion.
Solution Approach 2:
The patent introduces urate oxidase as an intermediary enzyme that directly converts uric acid to allantoin, bypassing the need for xanthine oxidase inhibition. This intermediary approach allows for more efficient uric acid metabolism with reduced kidney involvement, as the enzyme acts in the liver to directly process uric acid rather than requiring increased renal excretion of intermediates.
3Reliability
If foreign protein urate oxidase is used, then hyperuricemia is treated, but allergic reactions occur
Solution Approach 1:
The patent changes the protein source parameter from foreign fungi (Aspergillus niger, Aspergillus flavus) to animal sources (pig, baboon, cow), which are evolutionarily closer to humans. This parameter change reduces immunogenicity and allergic reactions while maintaining effective treatment of hyperuricemia, as the animal-derived proteins are more similar to human proteins and thus less likely to trigger immune responses.
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 circular RNA effectively expresses urate oxidase, reducing serum uric acid levels with prolonged effectiveness and minimal immunogenicity, requiring less frequent administration and offering a safer treatment option for hyperuricemia.
Implementation Method 1
circular RNAs (circRNAs) are a class of non-coding RNAs with a covalently closed continuous structure that is resistant to degradation by exonucleases
Implementation Method 2
The circular RNA may be derived from a recombinant nucleic acid molecule through in vitro transcription and splicing
Implementation Method 3
Urate oxidase, also known as uricase, is an enzyme involved in the metabolic pathway of purine degradation in organisms. During purine metabolism, most organisms produce uric acid, which can be catalyzed by uricase into allantoin.
Implementation Method 4
an internal ribosome entry site (IRES) fragment
Data Source
AI summary
A recombinant nucleic acid molecule for making a circular RNA and a preparation method for the circular RNA are provided. The recombinant nucleic acid molecule comprises elements operably linked to each other and arranged, in a 5′ to 3′ direction, in the following order: (a) an intron fragment which includes a full-length intron; (b) an E2 fragment which includes a downstream exon of the full-length intron; (c) an internal ribosome entry site (IRES) fragment; (d) a urate oxidase coding fragment; and (e) an E1 fragment which includes an upstream exon of the full-length intron; wherein the full-length intron, the downstream exon, and the upstream exon are from a same gene.