1
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MalagodaPathiranage K, Banerjee R, Martin C. A new approach to RNA synthesis: immobilization of stably and functionally co-tethered promoter DNA and T7 RNA polymerase. Nucleic Acids Res 2024; 52:10607-10618. [PMID: 39011885 PMCID: PMC11417385 DOI: 10.1093/nar/gkae599] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2024] [Revised: 06/11/2024] [Accepted: 06/30/2024] [Indexed: 07/17/2024] Open
Abstract
Current approaches to RNA synthesis/manufacturing require substantial (and incomplete) purification post-synthesis. We have previously demonstrated the synthesis of RNA from a complex in which T7 RNA polymerase is tethered to promoter DNA. In the current work, we extend this approach to demonstrate an extremely stable system of functional co-tethered complex to a solid support. Using the system attached to magnetic beads, we carry out more than 20 rounds of synthesis using the initial polymerase-DNA construct. We further demonstrate the wide utility of this system in the synthesis of short RNA, a CRISPR guide RNA, and a protein-coding mRNA. In all cases, the generation of self-templated double stranded RNA (dsRNA) impurities are greatly reduced, by both the tethering itself and by the salt-tolerance that local co-tethering provides. Transfection of the mRNA into HEK293T cells shows a correlation between added salt in the transcription reaction (which inhibits RNA rebinding that generates RNA-templated extensions) and significantly increased expression and reduced innate immune stimulation by the mRNA reaction product. These results point in the direction of streamlined processes for synthesis/manufacturing of high-quality RNA of any length, and at greatly reduced costs.
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Affiliation(s)
| | - Ruptanu Banerjee
- Department of Chemistry, University of Massachusetts Amherst, Amherst, MA 01003, USA
| | - Craig T Martin
- Department of Chemistry, University of Massachusetts Amherst, Amherst, MA 01003, USA
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2
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Yu B, Chen Y, Yan Y, Lu X, Zhu B. DNA-terminus-dependent transcription by T7 RNA polymerase and its C-helix mutants. Nucleic Acids Res 2024; 52:8443-8453. [PMID: 38979568 DOI: 10.1093/nar/gkae593] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2023] [Revised: 03/28/2024] [Accepted: 06/25/2024] [Indexed: 07/10/2024] Open
Abstract
The remarkable success of messenger RNA (mRNA)-based vaccines has underscored their potential as a novel biotechnology platform for vaccine development and therapeutic protein delivery. However, the single-subunit RNA polymerase from bacteriophage T7 widely used for in vitro transcription is well known to generate double-stranded RNA (dsRNA) by-products that strongly stimulate the mammalian innate immune response. The dsRNA was reported to be originated from self-templated RNA extension or promoter-independent transcription. Here, we identified that the primary source of the full-length dsRNA during in vitro transcription is the DNA-terminus-initiated transcription by T7 RNA polymerase. Guanosines or cytosines at the end of DNA templates enhance the DNA-terminus-initiated transcription. Moreover, we found that aromatic residues located at position 47 in the C-helix lead to a significant reduction in the production of full-length dsRNA. As a result, the mRNA synthesized using the T7 RNA polymerase G47W mutant exhibits higher expression efficiency and lower immunogenicity compared to the mRNA produced using the wild-type T7 RNA polymerase.
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Affiliation(s)
- Bingbing Yu
- Key Laboratory of Molecular Biophysics, Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Yifan Chen
- Key Laboratory of Molecular Biophysics, Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Yan Yan
- Key Laboratory of Molecular Biophysics, Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Xueling Lu
- Key Laboratory of Molecular Biophysics, Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Bin Zhu
- Key Laboratory of Molecular Biophysics, Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
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3
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Boman J, Marušič T, Seravalli TV, Skok J, Pettersson F, Nemec KŠ, Widmark H, Sekirnik R. Quality by design approach to improve quality and decrease cost of in vitro transcription of mRNA using design of experiments. Biotechnol Bioeng 2024. [PMID: 39014536 DOI: 10.1002/bit.28806] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2024] [Revised: 05/10/2024] [Accepted: 07/03/2024] [Indexed: 07/18/2024]
Abstract
In vitro transcription (IVT) reaction is an RNA polymerase-catalyzed production of messenger RNA (mRNA) from DNA template, and the unit operation with highest cost of goods in the mRNA drug substance production process. To decrease the cost of mRNA production, reagents should be optimally utilized. Due to the catalytic, multicomponent nature of the IVT reaction, optimization is a multi-factorial problem, ideally suited to design-of-experiment approach for optimization and identification of design space. We derived a data-driven model of the IVT reaction and explored factors that drive process yield (in g/L), including impact of nucleoside triphosphate (NTP) concentration and Mg:NTP ratio on reaction yield and how to optimize the main cost drivers RNA polymerase and DNA template, while minimizing dsRNA formation, a critical quality attribute in mRNA products. We report a methodological approach to derive an optimum reaction design, with which cost efficiency of the reaction was improved by 44%. We demonstrate the validity of the model on mRNA construct of different lengths. Finally, we maximized the yield of the IVT reaction to 24.9 ± 1.5 g/L in batch, thus doubling the highest ever reported IVT yield.
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Affiliation(s)
- Jimmy Boman
- Sartorius Stedim Data Analytics AB, Umeå, Sweden
| | - Tjaša Marušič
- Sartorius BIA Separations d.o.o., Sartorius Company, Ajdovščina, Slovenia
- Biotechnical Faculty, University of Ljubljana, Ljubljana, Slovenia
| | | | - Janja Skok
- Sartorius BIA Separations d.o.o., Sartorius Company, Ajdovščina, Slovenia
| | | | | | | | - Rok Sekirnik
- Sartorius BIA Separations d.o.o., Sartorius Company, Ajdovščina, Slovenia
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4
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Lenk R, Kleindienst W, Szabó GT, Baiersdörfer M, Boros G, Keller JM, Mahiny AJ, Vlatkovic I. Understanding the impact of in vitro transcription byproducts and contaminants. Front Mol Biosci 2024; 11:1426129. [PMID: 39050733 PMCID: PMC11266732 DOI: 10.3389/fmolb.2024.1426129] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2024] [Accepted: 06/14/2024] [Indexed: 07/27/2024] Open
Abstract
The success of messenger (m)RNA-based vaccines against SARS-CoV-2 during the COVID-19 pandemic has led to rapid growth and innovation in the field of mRNA-based therapeutics. However, mRNA production, whether in small amounts for research or large-scale GMP-grade for biopharmaceutics, is still based on the In Vitro Transcription (IVT) reaction developed in the early 1980s. The IVT reaction exploits phage RNA polymerase to catalyze the formation of an engineered mRNA that depends on a linearized DNA template, nucleotide building blocks, as well as pH, temperature, and reaction time. But depending on the IVT conditions and subsequent purification steps, diverse byproducts such as dsRNA, abortive RNAs and RNA:DNA hybrids might form. Unwanted byproducts, if not removed, could be formulated together with the full-length mRNA and cause an immune response in cells by activating host pattern recognition receptors. In this review, we summarize the potential types of IVT byproducts, their known biological activity, and how they can impact the efficacy and safety of mRNA therapeutics. In addition, we briefly overview non-nucleotide-based contaminants such as RNases, endotoxin and metal ions that, when present in the IVT reaction, can also influence the activity of mRNA-based drugs. We further discuss current approaches aimed at adjusting the IVT reaction conditions or improving mRNA purification to achieve optimal performance for medical applications.
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5
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Matsuda T, Hori H, Yamagami R. Rational design of oligonucleotides for enhanced in vitro transcription of small RNA. RNA (NEW YORK, N.Y.) 2024; 30:710-727. [PMID: 38423625 PMCID: PMC11098460 DOI: 10.1261/rna.079923.123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2023] [Accepted: 02/14/2024] [Indexed: 03/02/2024]
Abstract
All kinds of RNA molecules can be produced by in vitro transcription using T7 RNA polymerase using DNA templates obtained by solid-phase chemical synthesis, primer extension, PCR, or DNA cloning. The oligonucleotide design, however, is a challenge to nonexperts as this relies on a set of rules that have been established empirically over time. Here, we describe a Python program to facilitate the rational design of oligonucleotides, calculated with kinetic parameters for enhanced in vitro transcription (ROCKET). The Python tool uses thermodynamic parameters, performs folding-energy calculations, and selects oligonucleotides suitable for the polymerase extension reaction. These oligonucleotides improve yields of template DNA. With the oligonucleotides selected by the program, the tRNA transcripts can be prepared by a one-pot reaction of the DNA polymerase extension reaction and the transcription reaction. Also, the ROCKET-selected oligonucleotides provide greater transcription yields than that from oligonucleotides selected by Primerize, a leading software for designing oligonucleotides for in vitro transcription, due to the enhancement of template DNA synthesis. Apart from over 50 tRNA genes tested, an in vitro transcribed self-cleaving ribozyme was found to have catalytic activity. In addition, the program can be applied to the synthesis of mRNA, demonstrating the wide applicability of the ROCKET software.
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MESH Headings
- Transcription, Genetic
- Oligonucleotides/chemistry
- Oligonucleotides/genetics
- Oligonucleotides/chemical synthesis
- Software
- DNA-Directed RNA Polymerases/metabolism
- DNA-Directed RNA Polymerases/genetics
- RNA, Catalytic/genetics
- RNA, Catalytic/metabolism
- RNA, Catalytic/chemistry
- Thermodynamics
- RNA, Transfer/genetics
- RNA, Transfer/chemistry
- RNA, Transfer/metabolism
- Kinetics
- RNA, Messenger/genetics
- RNA, Messenger/chemistry
- RNA, Messenger/metabolism
- Viral Proteins/genetics
- Viral Proteins/metabolism
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Affiliation(s)
- Teppei Matsuda
- Department of Applied Chemistry, Graduate School of Science and Engineering, Ehime University, Matsuyama, Ehime 790-8577, Japan
| | - Hiroyuki Hori
- Department of Applied Chemistry, Graduate School of Science and Engineering, Ehime University, Matsuyama, Ehime 790-8577, Japan
| | - Ryota Yamagami
- Department of Applied Chemistry, Graduate School of Science and Engineering, Ehime University, Matsuyama, Ehime 790-8577, Japan
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6
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Feng X, Su Z, Cheng Y, Ma G, Zhang S. Messenger RNA chromatographic purification: advances and challenges. J Chromatogr A 2023; 1707:464321. [PMID: 37639849 DOI: 10.1016/j.chroma.2023.464321] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2023] [Revised: 08/16/2023] [Accepted: 08/20/2023] [Indexed: 08/31/2023]
Abstract
Messenger RNA (mRNA) technologies have shown great potential in prophylactic vaccines and therapeutic medicines due to their adaptability, rapidity, efficacy, and safety. The purity of mRNA determines the efficacy and safety of mRNA drugs. Though chromatographic technologies are currently employed in mRNA purification, they are facing challenges, mainly arising from the large size, relatively simple chemical composition, instability, and high resemblance of by-products to the target mRNA. In this review, we will first make a comprehensive analysis of physiochemical properties differences between mRNA and proteins, then the major challenges facing in mRNA purification and general considerations are highlighted. A detailed summary of the state-of-arts in mRNA chromatographic purification will be provided, which are mainly classified into physicochemical property-based (size, charge, and hydrophobicity) and chemical structure-based (phosphate backbone, bases, cap structure, and poly A tail) technologies. Efforts in eliminating dsRNA byproducts via post in vitro transcript (IVT) purification and by manipulating the IVT process to reduce the generation of dsRNA are highlighted. Finally, a brief summary of the current status of chromatographic purification of the emerging circular mRNA (circRNA) is provided. We hope this review will provide some useful guidance for the Quality by Design (QbD) of mRNA downstream process development.
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Affiliation(s)
- Xue Feng
- State Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinses Academy of Sciences, Beijing 100190, China; Department of Materials Science and Engineering, Monash University, Clayton, Victoria 3800, Australia; Monash Suzhou Research Institute, Monash University, SIP, Suzhou 215000, China
| | - Zhiguo Su
- State Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinses Academy of Sciences, Beijing 100190, China
| | - Yuan Cheng
- Department of Materials Science and Engineering, Monash University, Clayton, Victoria 3800, Australia; Monash Suzhou Research Institute, Monash University, SIP, Suzhou 215000, China
| | - Guanghui Ma
- State Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinses Academy of Sciences, Beijing 100190, China
| | - Songping Zhang
- State Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinses Academy of Sciences, Beijing 100190, China.
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7
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Cho E, Namgung J, Lee JS, Jang J, Jun BH, Kim DE. Mesoporous Silica Particle as an RNA Adsorbent for Facile Purification of In Vitro-Transcribed RNA. Int J Mol Sci 2023; 24:12408. [PMID: 37569783 PMCID: PMC10419103 DOI: 10.3390/ijms241512408] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2023] [Revised: 07/29/2023] [Accepted: 08/02/2023] [Indexed: 08/13/2023] Open
Abstract
Messenger RNA vaccines against SARS-CoV-2 hold great promise for the treatment of a wide range of diseases by using mRNA as a tool for generating vaccination antigens as well as therapeutic proteins in vivo. Increasing interest in mRNA preparation warrants reliable methods for in vitro transcription (IVT) of mRNA, which must entail the elimination of surplus side products such as immunogenic double-stranded RNA (dsRNA). We developed a facile method for the removal of dsRNA from in vitro transcribed RNA with mesoporous silica particles as RNA adsorbents. Various polyamines were tested for the facilitation of RNA adsorption onto mesoporous silica particles in the chromatography. Among the polyamines tested for RNA adsorption, spermidine showed a superior capability of RNA binding to the silica matrix. Mesoporous silica-adsorbed RNA was readily desorbed with elution buffer containing either salt, EDTA, or urea, possibly by disrupting electrostatic interaction and hydrogen bonding between RNA and the silica matrix. Purification of IVT RNA was enabled with the adsorption of RNA to mesoporous silica in a spermidine-containing buffer and subsequent elution with EDTA. By differing EDTA concentration in the eluting buffer, we demonstrated that at least 80% of the dsRNA can be removed from the mesoporous silica-adsorbed RNA. When compared with the cellulose-based removal of dsRNA from IVT RNA, the mesoporous silica-based purification of IVT RNA using spermidine and EDTA in binding and elution, respectively, exhibited more effective removal of dsRNA contaminants from IVT RNA. Thus, mRNA purification with mesoporous silica particles as RNA adsorbents is applicable for the facile preparation of nonimmunogenic RNA suitable for in vivo uses.
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Affiliation(s)
| | | | | | | | | | - Dong-Eun Kim
- Department of Bioscience and Biotechnology, Konkuk University, 120 Neundong-ro, Gwangjin-gu, Seoul 05029, Republic of Korea; (E.C.); (J.N.); (J.S.L.); (J.J.); (B.-H.J.)
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8
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Dousis A, Ravichandran K, Hobert EM, Moore MJ, Rabideau AE. An engineered T7 RNA polymerase that produces mRNA free of immunostimulatory byproducts. Nat Biotechnol 2023; 41:560-568. [PMID: 36357718 PMCID: PMC10110463 DOI: 10.1038/s41587-022-01525-6] [Citation(s) in RCA: 52] [Impact Index Per Article: 52.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Accepted: 09/22/2022] [Indexed: 11/12/2022]
Abstract
In vitro transcription (IVT) is a DNA-templated process for synthesizing long RNA transcripts, including messenger RNA (mRNA). For many research and commercial applications, IVT of mRNA is typically performed using bacteriophage T7 RNA polymerase (T7 RNAP) owing to its ability to produce full-length RNA transcripts with high fidelity; however, T7 RNAP can also produce immunostimulatory byproducts such as double-stranded RNA that can affect protein expression. Such byproducts require complex purification processes, using methods such as reversed-phase high-performance liquid chromatography, to yield safe and effective mRNA-based medicines. To minimize the need for downstream purification processes, we rationally and computationally engineered a double mutant of T7 RNAP that produces substantially less immunostimulatory RNA during IVT compared with wild-type T7 RNAP. The resulting mutant allows for a simplified production process with similar mRNA potency, lower immunostimulatory content and quicker manufacturing time compared with wild-type T7 RNAP. Herein, we describe the computational design and development of this improved T7 RNAP variant.
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Affiliation(s)
- Athanasios Dousis
- Moderna, Inc., Cambridge, MA, USA
- Tessera Therapeutics, Somerville, MA, USA
| | | | - Elissa M Hobert
- Moderna, Inc., Cambridge, MA, USA
- Laronde, Cambridge, MA, USA
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9
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Wang W, An X, Yan K, Li Q. Construction and Application of Orthogonal T7 Expression System in Eukaryote: An Overview. Adv Biol (Weinh) 2023; 7:e2200218. [PMID: 36464626 DOI: 10.1002/adbi.202200218] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2022] [Revised: 10/17/2022] [Indexed: 12/12/2022]
Abstract
The T7 system is an orthogonal transcription-system, which is characterized by simplicity, higher efficiency, and higher processivity, and it is used for protein or mRNA synthesis in various biological-systems. In comparison with prokaryotes, the construction of the T7 expression system is still on-going in eukaryotes, but it shows greatly applicable prospects. In the present paper, development of T7 expression system construction in eukaryotes is reviewed, including its construction in animal (mammalian cells, trypanosomatid protozoa, Xenopus oocytes, zebrafish), plant, and microorganism and its application in vaccine production and gene therapy. In addition, the innate challenges of T7 expression system construction in eukaryote and its potential application in vaccine production and gene therapy are discussed.
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Affiliation(s)
- Wenya Wang
- College of Life Science and Technology, Beijing University of Chemical Technology, Beijing, 100029, P. R. China
| | - Xiaoyan An
- College of Life Science and Technology, Beijing University of Chemical Technology, Beijing, 100029, P. R. China
| | - Kun Yan
- College of Life Science and Technology, Beijing University of Chemical Technology, Beijing, 100029, P. R. China
| | - Qiang Li
- Key Laboratory for Industrial Biocatalysis, Ministry of Education, Department of Chemical Engineering, Tsinghua University, Beijing, 100084, P. R. China
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10
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Wuebben C, Bartok E, Hartmann G. Innate sensing of mRNA vaccines. Curr Opin Immunol 2022; 79:102249. [PMID: 36334350 DOI: 10.1016/j.coi.2022.102249] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2022] [Accepted: 09/05/2022] [Indexed: 01/30/2023]
Abstract
With the recent success of mRNA vaccines and the approval of several RNA oligonucleotide therapeutics, RNA holds great promise for future drug development. The rise of RNA therapeutics has been enabled by the tremendous progress in our understanding of the sophisticated cellular mechanisms that disarm potentially dangerous exogenous RNA and safeguard RNA homeostasis. Exogenous RNA, such as an mRNA vaccine when injected, faces an intricate system of immune-sensing receptors, restriction factors, and nucleases referred to as nucleic acid immunity. A careful analysis of the functional interaction between the innate response to mRNA, the efficacy to translate the encoded protein antigen, and the quality of the resulting adaptive immunity bears great potential for further improvement of mRNA vaccines and RNA therapeutics for various clinical applications. In this review, we summarize the most recent efforts to advance mRNA vaccines by capitalizing on recent insight in innate RNA sensing.
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Affiliation(s)
- Christine Wuebben
- Institute of Clinical Chemistry and Clinical Pharmacology, University Hospital Bonn, Campus Venusberg, Bonn, Germany
| | - Eva Bartok
- Institute of Experimental Haematology and Transfusion Medicine, University Hospital Bonn, Campus Venusberg, Bonn, Germany
| | - Gunther Hartmann
- Institute of Clinical Chemistry and Clinical Pharmacology, University Hospital Bonn, Campus Venusberg, Bonn, Germany; German Center of Infection Research (DZIF), site Bonn-Cologne, Germany.
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11
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Nagaraj S, Stankiewicz-Drogon A, Darzynkiewicz E, Grzela R. RNA sensor response in HeLa cells for transfected mRNAs prepared in vitro by SP6 and HiT7 RNA polymerases: A comparative study. Front Bioeng Biotechnol 2022; 10:1017934. [PMID: 36406230 PMCID: PMC9669293 DOI: 10.3389/fbioe.2022.1017934] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Accepted: 10/19/2022] [Indexed: 08/18/2023] Open
Abstract
In vitro transcribed (IVT) synthetic mRNAs are in high demand due to their attractive bench to clinic translational processes. Mainly, the procedure to make IVT mRNA using bacteriophage RNA polymerases (RNAP) is relatively uncomplicated and scalable to produce large quantities in a short time period. However, IVT mRNA preparations are accompanied by contaminants such as double-stranded RNA (dsRNA) as by-products that elicit undesired cellular immune responses upon transfections. Therefore, removing dsRNA contaminants is critical in IVT mRNA preparations for therapeutic applications. One such method to minimize dsRNA contaminants is to use genetically modified thermostable bacteriophage polymerase, HiT7 RNAP that performs IVT reaction at a higher temperature than typically used. However, the cellular RNA sensor response for IVT mRNA preparations by HiT7 RNAP is not characterized. Here, we compared the cellular RNA sensor response for mRNAs prepared by HiT7 RNAP (at 50°C) and SP6 RNAP (at 37°C) in HeLa cells. We show that IVT mRNA preparations by HiT7 RNAP reduced the dsRNA levels and dsRNA specific RNA sensor response (retinoic acid-inducible gene I, RIG-I and melanoma differentiation-associated 5, MDA5) compared to the IVT mRNA preparations by SP6 RNAP. Similarly, the incorporation of pseudouridine nucleotides instead of uridine nucleotides reduced dsRNA sensor response and increased the mRNA translation. Overall, the least dsRNA mediated RNA sensor response is observed when mRNA is synthesized by HiT7 RNAP and incorporated with pseudouridine nucleotides.
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Affiliation(s)
- Siranjeevi Nagaraj
- Interdisciplinary Laboratory of Molecular Biology and Biophysics, Centre of New Technologies, University of WarsawWarsaw, Poland
| | - Anna Stankiewicz-Drogon
- Division of Biophysics, Institute of Experimental Physics, Faculty of Physics, University of WarsawWarsaw, Poland
| | - Edward Darzynkiewicz
- Interdisciplinary Laboratory of Molecular Biology and Biophysics, Centre of New Technologies, University of WarsawWarsaw, Poland
- Division of Biophysics, Institute of Experimental Physics, Faculty of Physics, University of WarsawWarsaw, Poland
| | - Renata Grzela
- Interdisciplinary Laboratory of Molecular Biology and Biophysics, Centre of New Technologies, University of WarsawWarsaw, Poland
- Division of Biophysics, Institute of Experimental Physics, Faculty of Physics, University of WarsawWarsaw, Poland
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12
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Hough J, Howard JD, Brown S, Portwood DE, Kilby PM, Dickman MJ. Strategies for the production of dsRNA biocontrols as alternatives to chemical pesticides. Front Bioeng Biotechnol 2022; 10:980592. [PMID: 36299286 PMCID: PMC9588923 DOI: 10.3389/fbioe.2022.980592] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Accepted: 08/23/2022] [Indexed: 01/09/2023] Open
Abstract
Current crop pest control strategies rely on insecticidal and fungicidal sprays, plant genetic resistance, transgenes and agricultural practices. However, many insects, plant viruses, and fungi have no current means of control or have developed resistance against traditional pesticides. dsRNA is emerging as a novel sustainable method of plant protection as an alternative to traditional chemical pesticides. The successful commercialisation of dsRNA based biocontrols for effective pest management strategies requires the economical production of large quantities of dsRNA combined with suitable delivery methods to ensure RNAi efficacy against the target pest. A number of methods exist for the production and delivery of dsRNA based biocontrols and here we review alternative methods currently employed and emerging new approaches for their production. Additionally, we highlight potential challenges that will need to be addressed prior to widespread adoption of dsRNA biocontrols as novel sustainable alternatives to traditional chemical pesticides.
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Affiliation(s)
- James Hough
- Department of Chemical and Biological Engineering, University of Sheffield, Sheffield, United Kingtom
| | - John D. Howard
- Department of Chemical and Biological Engineering, University of Sheffield, Sheffield, United Kingtom
| | - Stephen Brown
- Sheffield RNAi Screening Facility, School of Biosciences, University of Sheffield, Sheffield, United Kingtom
| | - David E. Portwood
- Syngenta, Jealott’s Hill International Research Centre, Bracknell, United Kingdom
| | - Peter M. Kilby
- Syngenta, Jealott’s Hill International Research Centre, Bracknell, United Kingdom
| | - Mark J. Dickman
- Department of Chemical and Biological Engineering, University of Sheffield, Sheffield, United Kingtom
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13
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Piao X, Yadav V, Wang E, Chang W, Tau L, Lindenmuth BE, Wang SX. Double-stranded RNA reduction by chaotropic agents during in vitro transcription of messenger RNA. MOLECULAR THERAPY - NUCLEIC ACIDS 2022; 29:618-624. [PMID: 36090758 PMCID: PMC9421179 DOI: 10.1016/j.omtn.2022.08.001] [Citation(s) in RCA: 28] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/24/2021] [Accepted: 08/01/2022] [Indexed: 10/26/2022]
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14
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Liu CX, Guo SK, Nan F, Xu YF, Yang L, Chen LL. RNA circles with minimized immunogenicity as potent PKR inhibitors. Mol Cell 2021; 82:420-434.e6. [PMID: 34951963 DOI: 10.1016/j.molcel.2021.11.019] [Citation(s) in RCA: 52] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2021] [Revised: 08/31/2021] [Accepted: 11/17/2021] [Indexed: 12/16/2022]
Abstract
Exon back-splicing-generated circular RNAs, as a group, can suppress double-stranded RNA (dsRNA)-activated protein kinase R (PKR) in cells. We have sought to synthesize immunogenicity-free, short dsRNA-containing RNA circles as PKR inhibitors. Here, we report that RNA circles synthesized by permuted self-splicing thymidylate synthase (td) introns from T4 bacteriophage or by Anabaena pre-tRNA group I intron could induce an immune response. Autocatalytic splicing introduces ∼74 nt td or ∼186 nt Anabaena extraneous fragments that can distort the folding status of original circular RNAs or form structures themselves to provoke innate immune responses. In contrast, synthesized RNA circles produced by T4 RNA ligase without extraneous fragments exhibit minimized immunogenicity. Importantly, directly ligated circular RNAs that form short dsRNA regions efficiently suppress PKR activation 103- to 106-fold higher than reported chemical compounds C16 and 2-AP, highlighting the future use of circular RNAs as potent inhibitors for diseases related to PKR overreaction.
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Affiliation(s)
- Chu-Xiao Liu
- State Key Laboratory of Molecular Biology, Shanghai Key Laboratory of Molecular Andrology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 320 Yueyang Road, Shanghai 200031, China
| | - Si-Kun Guo
- State Key Laboratory of Molecular Biology, Shanghai Key Laboratory of Molecular Andrology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 320 Yueyang Road, Shanghai 200031, China
| | - Fang Nan
- CAS Key Laboratory of Computational Biology, Shanghai Institute of Nutrition and Health, Shanghai Institutes for Biological Sciences, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 320 Yueyang Road, Shanghai 200031, China
| | - Yi-Feng Xu
- State Key Laboratory of Molecular Biology, Shanghai Key Laboratory of Molecular Andrology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 320 Yueyang Road, Shanghai 200031, China
| | - Li Yang
- CAS Key Laboratory of Computational Biology, Shanghai Institute of Nutrition and Health, Shanghai Institutes for Biological Sciences, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 320 Yueyang Road, Shanghai 200031, China; School of Life Science and Technology, ShanghaiTech University, 100 Haike Road, Shanghai 201210, China
| | - Ling-Ling Chen
- State Key Laboratory of Molecular Biology, Shanghai Key Laboratory of Molecular Andrology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 320 Yueyang Road, Shanghai 200031, China; School of Life Science and Technology, ShanghaiTech University, 100 Haike Road, Shanghai 201210, China; School of Life Science, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou, China.
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15
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Minnaert AK, Vanluchene H, Verbeke R, Lentacker I, De Smedt SC, Raemdonck K, Sanders NN, Remaut K. Strategies for controlling the innate immune activity of conventional and self-amplifying mRNA therapeutics: Getting the message across. Adv Drug Deliv Rev 2021; 176:113900. [PMID: 34324884 PMCID: PMC8325057 DOI: 10.1016/j.addr.2021.113900] [Citation(s) in RCA: 60] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Revised: 07/20/2021] [Accepted: 07/22/2021] [Indexed: 02/07/2023]
Abstract
The recent approval of messenger RNA (mRNA)-based vaccines to combat the SARS-CoV-2 pandemic highlights the potential of both conventional mRNA and self-amplifying mRNA (saRNA) as a flexible immunotherapy platform to treat infectious diseases. Besides the antigen it encodes, mRNA itself has an immune-stimulating activity that can contribute to vaccine efficacy. This self-adjuvant effect, however, will interfere with mRNA translation and may influence the desired therapeutic outcome. To further exploit its potential as a versatile therapeutic platform, it will be crucial to control mRNA's innate immune-stimulating properties. In this regard, we describe the mechanisms behind the innate immune recognition of mRNA and provide an extensive overview of strategies to control its innate immune-stimulating activity. These strategies range from modifications to the mRNA backbone itself, optimization of production and purification processes to the combination with innate immune inhibitors. Furthermore, we discuss the delicate balance of the self-adjuvant effect in mRNA vaccination strategies, which can be both beneficial and detrimental to the therapeutic outcome.
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Affiliation(s)
- An-Katrien Minnaert
- Ghent Research Group on Nanomedicines, Laboratory of General Biochemistry and Physical Pharmacy, Faculty of Pharmaceutical Sciences, Ghent University, Ottergemsesteenweg 460, 9000 Ghent, Belgium; Cancer Research Institute Ghent (CRIG), Ghent, Belgium.
| | - Helena Vanluchene
- Ghent Research Group on Nanomedicines, Laboratory of General Biochemistry and Physical Pharmacy, Faculty of Pharmaceutical Sciences, Ghent University, Ottergemsesteenweg 460, 9000 Ghent, Belgium; Cancer Research Institute Ghent (CRIG), Ghent, Belgium.
| | - Rein Verbeke
- Ghent Research Group on Nanomedicines, Laboratory of General Biochemistry and Physical Pharmacy, Faculty of Pharmaceutical Sciences, Ghent University, Ottergemsesteenweg 460, 9000 Ghent, Belgium; Cancer Research Institute Ghent (CRIG), Ghent, Belgium.
| | - Ine Lentacker
- Ghent Research Group on Nanomedicines, Laboratory of General Biochemistry and Physical Pharmacy, Faculty of Pharmaceutical Sciences, Ghent University, Ottergemsesteenweg 460, 9000 Ghent, Belgium; Cancer Research Institute Ghent (CRIG), Ghent, Belgium.
| | - Stefaan C De Smedt
- Ghent Research Group on Nanomedicines, Laboratory of General Biochemistry and Physical Pharmacy, Faculty of Pharmaceutical Sciences, Ghent University, Ottergemsesteenweg 460, 9000 Ghent, Belgium; Cancer Research Institute Ghent (CRIG), Ghent, Belgium.
| | - Koen Raemdonck
- Ghent Research Group on Nanomedicines, Laboratory of General Biochemistry and Physical Pharmacy, Faculty of Pharmaceutical Sciences, Ghent University, Ottergemsesteenweg 460, 9000 Ghent, Belgium; Cancer Research Institute Ghent (CRIG), Ghent, Belgium.
| | - Niek N Sanders
- Laboratory of Gene Therapy, Department of Nutrition, Genetics and Ethology, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium; Cancer Research Institute Ghent (CRIG), Ghent, Belgium.
| | - Katrien Remaut
- Ghent Research Group on Nanomedicines, Laboratory of General Biochemistry and Physical Pharmacy, Faculty of Pharmaceutical Sciences, Ghent University, Ottergemsesteenweg 460, 9000 Ghent, Belgium; Cancer Research Institute Ghent (CRIG), Ghent, Belgium.
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16
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Karlsson H, Feyrer H, Baronti L, Petzold K. Production of Structured RNA Fragments by In Vitro Transcription and HPLC Purification. Curr Protoc 2021; 1:e159. [PMID: 34138527 DOI: 10.1002/cpz1.159] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The understanding of the functional importance of RNA has increased enormously in the last decades. This has required research on the RNA molecules themselves, with the concomitant need for obtaining purified RNA samples, such as for structural studies by NMR or other methods. The main method to create labeled and unlabeled RNA, T7 in vitro transcription, suffers from sequence-dependent yield and often low homogeneity for short constructs (<100 nt) and requires laborious purification. Additionally, the design of structured RNA fragments mimicking the structure of a larger biological RNA is often not straightforward. Secondary structure simulations can be used to make reliable predictions about the folding of a particular RNA fragment. In this article, we describe how to design an RNA construct of interest from a larger sequence, and we combine several previously published improvements of the in vitro transcription method, such as the use of 2'-methoxy modifications and dimethyl sulfoxide or the use of tandem repeats, to increase yield and purity of in vitro-transcribed RNA. Together with a high-performance liquid chromatography (HPLC) purification procedure using both reversed-phase ion-pairing and ion-exchange HPLC, we provide a robust protocol to obtain highly pure RNA of short to intermediate length in large quantities. The protocol optimizes yield, especially for RNA starting with nucleotides other than G. At the same time, it is simplified, and the required time is reduced. The protocols described here constitute a versatile pipeline for the production of purified RNA samples and are suitable for users with little experience in liquid chromatography. © 2021 The Authors. Basic Protocol 1: RNA construct design Basic Protocol 2: DNA template production and in vitro transcription Alternate Protocol: Tandem transcription and RNase H cleavage Basic Protocol 3: Reversed-phase ion-pairing HPLC purification Basic Protocol 4: Ion-exchange HPLC purification.
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Affiliation(s)
- Hampus Karlsson
- Department of Medical Biochemistry and Biophysics, Karolinska Institute, Stockholm, Sweden
| | - Hannes Feyrer
- Department of Medical Biochemistry and Biophysics, Karolinska Institute, Stockholm, Sweden
| | - Lorenzo Baronti
- Department of Medical Biochemistry and Biophysics, Karolinska Institute, Stockholm, Sweden.,Current address: Department of Chemistry, Technical University of Munich, Garching, Germany
| | - Katja Petzold
- Department of Medical Biochemistry and Biophysics, Karolinska Institute, Stockholm, Sweden
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17
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Bloom K, van den Berg F, Arbuthnot P. Self-amplifying RNA vaccines for infectious diseases. Gene Ther 2020; 28:117-129. [PMID: 33093657 PMCID: PMC7580817 DOI: 10.1038/s41434-020-00204-y] [Citation(s) in RCA: 207] [Impact Index Per Article: 51.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Revised: 09/29/2020] [Accepted: 10/08/2020] [Indexed: 12/28/2022]
Abstract
Vaccinology is shifting toward synthetic RNA platforms which allow for rapid, scalable, and cell-free manufacturing of prophylactic and therapeutic vaccines. The simple development pipeline is based on in vitro transcription of antigen-encoding sequences or immunotherapies as synthetic RNA transcripts, which are then formulated for delivery. This approach may enable a quicker response to emerging disease outbreaks, as is evident from the swift pursuit of RNA vaccine candidates for the global SARS-CoV-2 pandemic. Both conventional and self-amplifying RNAs have shown protective immunization in preclinical studies against multiple infectious diseases including influenza, RSV, Rabies, Ebola, and HIV-1. Self-amplifying RNAs have shown enhanced antigen expression at lower doses compared to conventional mRNA, suggesting this technology may improve immunization. This review will explore how self-amplifying RNAs are emerging as important vaccine candidates for infectious diseases, the advantages of synthetic manufacturing approaches, and their potential for preventing and treating chronic infections.
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Affiliation(s)
- Kristie Bloom
- Wits/SAMRC Antiviral Gene Therapy Research Unit, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Private Bag 3, WITS, Johannesburg, 2050, South Africa.
| | - Fiona van den Berg
- Wits/SAMRC Antiviral Gene Therapy Research Unit, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Private Bag 3, WITS, Johannesburg, 2050, South Africa
| | - Patrick Arbuthnot
- Wits/SAMRC Antiviral Gene Therapy Research Unit, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Private Bag 3, WITS, Johannesburg, 2050, South Africa
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18
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Torelli E, Kozyra J, Shirt-Ediss B, Piantanida L, Voïtchovsky K, Krasnogor N. Cotranscriptional Folding of a Bio-orthogonal Fluorescent Scaffolded RNA Origami. ACS Synth Biol 2020; 9:1682-1692. [PMID: 32470289 DOI: 10.1021/acssynbio.0c00009] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The scaffolded origami technique is an attractive tool for engineering nucleic acid nanostructures. This paper demonstrates scaffolded RNA origami folding in vitro in which, for the first time, all components are transcribed simultaneously in a single-pot reaction. Double-stranded DNA sequences are transcribed by T7 RNA polymerase into scaffold and staple strands able to correctly fold in a high synthesis yield into the nanoribbon. Synthesis is successfully confirmed by atomic force microscopy, and the unpurified transcription reaction mixture is analyzed by an in gel-imaging assay where the transcribed RNA nanoribbons are able to capture the specific dye through the reconstituted split Broccoli aptamer showing a clear green fluorescent band. Finally, we simulate the RNA origami in silico using the nucleotide-level coarse-grained model oxRNA to investigate the thermodynamic stability of the assembled nanostructure in isothermal conditions over a period of time. Our work suggests that the scaffolded origami technique is a viable, and potentially more powerful, assembly alternative to the single-stranded origami technique for future in vivo applications.
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Affiliation(s)
- Emanuela Torelli
- Interdisciplinary Computing and Complex BioSystems (ICOS), Centre for Synthetic Biology and Bioeconomy (CSBB), Devonshire Building, Newcastle University, Newcastle upon Tyne NE1 7RX, United Kingdom
| | - Jerzy Kozyra
- Interdisciplinary Computing and Complex BioSystems (ICOS), Centre for Synthetic Biology and Bioeconomy (CSBB), Devonshire Building, Newcastle University, Newcastle upon Tyne NE1 7RX, United Kingdom
| | - Ben Shirt-Ediss
- Interdisciplinary Computing and Complex BioSystems (ICOS), Centre for Synthetic Biology and Bioeconomy (CSBB), Devonshire Building, Newcastle University, Newcastle upon Tyne NE1 7RX, United Kingdom
| | - Luca Piantanida
- Department of Physics, Durham University, Durham DH1 3LE, United Kingdom
| | - Kislon Voïtchovsky
- Department of Physics, Durham University, Durham DH1 3LE, United Kingdom
| | - Natalio Krasnogor
- Interdisciplinary Computing and Complex BioSystems (ICOS), Centre for Synthetic Biology and Bioeconomy (CSBB), Devonshire Building, Newcastle University, Newcastle upon Tyne NE1 7RX, United Kingdom
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19
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Wu MZ, Asahara H, Tzertzinis G, Roy B. Synthesis of low immunogenicity RNA with high-temperature in vitro transcription. RNA (NEW YORK, N.Y.) 2020; 26:345-360. [PMID: 31900329 PMCID: PMC7025508 DOI: 10.1261/rna.073858.119] [Citation(s) in RCA: 64] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Accepted: 12/30/2019] [Indexed: 05/26/2023]
Abstract
The use of synthetic RNA for therapeutics requires that the in vitro synthesis process be robust and efficient. The technology used for the synthesis of these in vitro-transcribed RNAs, predominantly using phage RNA polymerases (RNAPs), is well established. However, transcripts synthesized with RNAPs are known to display an immune-stimulatory activity in vivo that is often undesirable. Previous studies have identified double-stranded RNA (dsRNA), a major by-product of the in vitro transcription (IVT) process, as a trigger of cellular immune responses. Here we describe the characterization of a high-temperature IVT process using thermostable T7 RNAPs to synthesize functional mRNAs that demonstrate reduced immunogenicity without the need for a post-synthesis purification step. We identify features that drive the production of two kinds of dsRNA by-products-one arising from 3' extension of the run-off product and one formed by the production of antisense RNAs-and demonstrate that at a high temperature, T7 RNAP has reduced 3'-extension of the run-off product. We show that template-encoded poly(A) tailing does not affect 3'-extension but reduces the formation of the antisense RNA by-products. Combining high-temperature IVT with template-encoded poly(A) tailing prevents the formation of both kinds of dsRNA by-products generating functional mRNAs with reduced immunogenicity.
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Affiliation(s)
- Monica Z Wu
- RNA and Genome Editing, New England Biolabs, Inc., Ipswich, Massachusetts 01938, USA
| | - Haruichi Asahara
- RNA and Genome Editing, New England Biolabs, Inc., Ipswich, Massachusetts 01938, USA
| | - George Tzertzinis
- RNA and Genome Editing, New England Biolabs, Inc., Ipswich, Massachusetts 01938, USA
| | - Bijoyita Roy
- RNA and Genome Editing, New England Biolabs, Inc., Ipswich, Massachusetts 01938, USA
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