Recombinant RNA Template Unit for Prolonged Expression
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Solution Overview
Problem
Current methods for cell reprogramming using viral vectors face challenges such as genomic integration leading to insertional mutagenesis, long-term persistence of reprogrammed cells causing immune system burden, and immune responses, while mRNA transfection is limited by rapid mRNA degradation and short protein expression duration.
Innovation Solution
The use of a recombinant RNA template unit (rTeUn) that includes regulatory sequences from negative strand RNA viruses, stabilized by viral proteins NP, P, and L, allowing for prolonged expression by forming a stable complex that resists degradation and can be reactivated for extended protein production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If viral vectors are used for cell reprogramming, then reprogramming efficiency is improved, but genomic integration occurs leading to insertional mutagenesis and potential transformation
Solution Approach 1:
The patent extracts the harmful integration capability from the viral vector system by using non-integrating viral vectors (such as adenovirus, adeno-associated virus, or viral mRNA) that can still deliver reprogramming factors efficiently without integrating into the host genome, thereby maintaining productivity while eliminating the harmful effect
Solution Approach 2:
The patent uses mRNA as an intermediary carrier to deliver reprogramming factors to cells. The mRNA translates proteins in the cytoplasm without requiring genomic integration, serving as a temporary mediator that achieves reprogramming efficiency while avoiding insertional mutagenesis
2Object-affected harmful factors
If non-integrated viral vectors are used, then insertional mutagenesis risk is reduced, but long-term persistence of reprogrammed cells increases immune system burden
Solution Approach 1:
The patent employs dynamically controllable viral vectors with inducible expression systems (such as tetracycline-responsive promoters or Cre-lox systems) that allow the persistence of reprogrammed cells to be adjusted on demand, reducing immune burden by limiting long-term presence while maintaining reprogramming capability
Solution Approach 2:
The patent uses self-amplifying RNA or episomal vectors that can maintain continuous expression of reprogramming factors without long-term genomic integration, providing sustained reprogramming action while avoiding permanent cellular modification that would increase immune burden
3Productivity
If viral vectors are used for reprogramming, then reprogramming capability is improved, but continuing production of viral proteins induces host immune responses
Solution Approach 1:
The patent extracts only the essential reprogramming function from viral vectors by using viral mRNA or viral protein delivery systems that lack complete viral genomes, thereby eliminating the ability to produce viral proteins that would trigger immune responses while retaining reprogramming capability
Solution Approach 2:
The patent uses transient mRNA or short-lived viral vectors that degrade naturally after delivering reprogramming factors, avoiding long-term viral protein production that would induce immune responses, effectively using disposable delivery systems rather than persistent viral infections
4Object-affected harmful factors
If synthetic mRNA is used for cell reprogramming, then genomic integration is avoided, but mRNA degradation occurs rapidly limiting expression duration
Solution Approach 1:
The patent modifies the chemical parameters of mRNA by adding stabilizing modifications such as 5' cap structures, poly(A) tails, and chemically modified nucleosides (e.g., pseudouridine, 5-methylcytidine) that increase mRNA half-life and resistance to degradation, thereby extending expression duration while maintaining the non-integrating advantage
Solution Approach 2:
The patent creates composite mRNA structures by combining multiple functional elements including 5' caps, 3' poly(A) tails, internal ribosome entry sites (IRES), and stabilizing sequences to form a composite molecule that resists degradation and extends persistence time while avoiding genomic integration
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
This approach enables prolonged and controlled expression of recombinant proteins, avoiding genomic integration and immune responses, with the rTeUn remaining stable in the cytosol for weeks and potentially months, facilitating safer and more effective cell reprogramming.
Implementation Method 1
stabilized by viral proteins NP, P, and L, allowing for prolonged expression by forming a stable complex that resists degradation
Data Source
AI summary
Compositions for transient but prolonged exogenous mRNA expression through the use of the transcription system of negative strand RNA viruses, and methods of use thereof are disclosed. In some embodiments, the system contains only RNAs and does not include any DNA molecules. The compositions typically include an RNA template unit (rTeUn) that includes a virus regulatory sequences operably linked to a coding sequence of interest. The rTeUn is typically transfected to a host cell's cytoplasm in the presence of virus expression system proteins that mediate replication of the rTeUn and transcription of the transgene. The rTeUn RNA bonded to viral proteins exhibits high resistance to degradation, prolonged duration of expression, and is free of viral genes. The compositions can be used to reprogram cell. For example, the compositions and methods can be used to redirected lymphocytes to target cancer cells, or to dedifferentiate somatic cells into induce pluripotent stem cells.