dsRNA-Free mRNA Purification for Safer iPSC Reprogramming
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Solution Overview
Problem
Existing methods for generating induced pluripotent stem cells (iPSCs) using viral or non-viral delivery of reprogramming factors are inefficient and can lead to genome integration, cancer, and significant cytotoxicity due to activation of innate immune responses by repeated introduction of in vitro-synthesized mRNA.
Innovation Solution
Development of RNA compositions and methods to purify in vitro-synthesized ssRNA or mRNA to be substantially free of dsRNA using RNase III treatment with 1-4 mM magnesium cations, reducing innate immune response activation and cytotoxicity, enabling efficient reprogramming of somatic cells to iPSCs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If in vitro-synthesized mRNA is repeatedly introduced into cells to induce reprogramming, then reprogramming efficiency is improved, but cytotoxicity and immune response activation increase
Solution Approach 1:
The patent applies this principle by using pseudouridine modification to convert the harmful recognition of mRNA by immune sensors into a beneficial outcome. The modified nucleoside makes the mRNA less immunogenic while maintaining its protein-coding function, thus enabling repeated introductions without triggering cytotoxic immune responses. This transforms the originally harmful immune recognition into a tolerable condition that supports sustained reprogramming.
Solution Approach 2:
The patent changes the chemical parameter of the mRNA by substituting uridine with pseudouridine at specific positions. This chemical modification alters the physical-chemical properties of the mRNA molecule, reducing its recognition by cellular RNA sensors while preserving its ability to be translated into reprogramming proteins. The parameter change enables repeated mRNA introductions without accumulating cytotoxic effects.
2Productivity
If viral vectors are used to deliver reprogramming factors, then delivery efficiency is improved, but genome integration and cancer risk increase
Solution Approach 1:
The patent extracts the reprogramming function from viral vectors and implements it through non-integrating mRNA delivery. By removing the viral genome integration mechanism and using only the protein-coding capacity of mRNA, the invention achieves efficient delivery without the harmful genomic integration and cancer risks associated with viral vectors.
Solution Approach 2:
The patent uses mRNA as an intermediary carrier to deliver reprogramming factors without direct genome integration. Instead of using viral DNA that integrates into the host genome, the mRNA serves as a temporary intermediary that is translated into proteins and then degraded, achieving efficient factor delivery while avoiding permanent genomic changes and cancer risk.
3Reliability
If non-viral delivery methods are used to avoid genome integration, then genome integrity is improved, but delivery efficiency and reprogramming speed decrease
Solution Approach 1:
The patent changes the chemical parameters of the delivered molecule by using pseudouridine-modified mRNA instead of standard mRNA or DNA. This modification enhances the stability and translation efficiency of the mRNA while maintaining its non-integrating nature, thus achieving both high delivery efficiency and genome integrity simultaneously.
Solution Approach 2:
The patent creates a composite molecular structure by combining modified nucleosides (pseudouridine) with standard mRNA components. This composite mRNA structure exhibits improved properties including enhanced stability, reduced immune recognition, and increased translation efficiency, thereby achieving high delivery efficiency while maintaining genome integrity through non-integrating delivery.
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 method allows for effective and safe reprogramming of human somatic cells to iPSCs with reduced cytotoxicity and immune response, facilitating faster and more efficient generation of patient-specific therapies.
Implementation Method 1
contacting the in vitro-synthesized ssRNA or mRNA with RNase III protein in a buffered aqueous solution comprising magnesium cations at a concentration of about 1-4 mM; and a salt providing an ionic strength at least equivalent to about 50 mM potassium acetate or potassium glutamate, and incubating under conditions wherein the RNA composition is generated
Data Source
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AI summary
The present invention relates to compositions, kits and methods for making and using RNA compositions comprising in vitro-synthesized ssRNA inducing a biological or biochemical effect in a mammalian cell or organism into which the RNA composition is repeatedly or continuously introduced. In certain embodiments, the invention provides compositions and methods for changing the state of differentiation or phenotype of a human or other vertebrate cell. For example, the present invention provides mRNA and methods for reprogramming cells that exhibit a first differentiated state or phenotype to cells that exhibit a second differentiated state or phenotype, such as to reprogram human somatic cells to pluripotent stem cells.