1
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Düchs MJ, Kratzer RF, Vieyra-Garcia P, Strobel B, Schönberger T, Groß P, Aljayyoussi G, Gupta A, Lang I, Klein H, Morilla SM, Hopf S, Park J, Kreuz S, Klugmann M, Igney FH. Riboswitch-controlled IL-12 gene therapy reduces hepatocellular cancer in mice. Front Immunol 2024; 15:1360063. [PMID: 38558809 PMCID: PMC10979303 DOI: 10.3389/fimmu.2024.1360063] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Accepted: 02/14/2024] [Indexed: 04/04/2024] Open
Abstract
Hepatocellular carcinoma (HCC) and solid cancers with liver metastases are indications with high unmet medical need. Interleukin-12 (IL-12) is a proinflammatory cytokine with substantial anti-tumor properties, but its therapeutic potential has not been realized due to severe toxicity. Here, we show that orthotopic liver tumors in mice can be treated by targeting hepatocytes via systemic delivery of adeno-associated virus (AAV) vectors carrying the murine IL-12 gene. Controlled cytokine production was achieved in vivo by using the tetracycline-inducible K19 riboswitch. AAV-mediated expression of IL-12 led to STAT4 phosphorylation, interferon-γ (IFNγ) production, infiltration of T cells and, ultimately, tumor regression. By detailed analyses of efficacy and tolerability in healthy and tumor-bearing animals, we could define a safe and efficacious vector dose. As a potential clinical candidate, we characterized vectors carrying the human IL-12 (huIL-12) gene. In mice, bioactive human IL-12 was expressed in a vector dose-dependent manner and could be induced by tetracycline, suggesting tissue-specific AAV vectors with riboswitch-controlled expression of highly potent proinflammatory cytokines as an attractive approach for vector-based cancer immunotherapy.
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Affiliation(s)
- Matthias J. Düchs
- Research Beyond Borders, Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach an der Riss, Germany
| | - Ramona F. Kratzer
- Cancer Immunology and Immune Modulation, Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach an der Riss, Germany
| | - Pablo Vieyra-Garcia
- Cancer Immunology and Immune Modulation, Boehringer Ingelheim RCV GmbH & Co. KG, Vienna, Austria
| | - Benjamin Strobel
- Drug Discovery Sciences, Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach an der Riss, Germany
| | - Tanja Schönberger
- Drug Discovery Sciences, Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach an der Riss, Germany
| | - Peter Groß
- Drug Discovery Sciences, Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach an der Riss, Germany
| | - Ghaith Aljayyoussi
- Drug Discovery Sciences, Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach an der Riss, Germany
| | - Aradhana Gupta
- Nonclinical Drug Safety, Boehringer Ingelheim Pharmaceuticals, Inc., Ridgefield, CT, United States
| | - Isabel Lang
- Research Beyond Borders, Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach an der Riss, Germany
| | - Holger Klein
- Global Computational Biology and Digital Sciences, Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach an der Riss, Germany
| | - Sandra Martinez Morilla
- Cancer Immunology and Immune Modulation, Boehringer Ingelheim RCV GmbH & Co. KG, Ridgefield, CT, United States
| | - Stefan Hopf
- Cancer Immunology and Immune Modulation, Boehringer Ingelheim RCV GmbH & Co. KG, Vienna, Austria
| | - John Park
- Cancer Immunology and Immune Modulation, Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach an der Riss, Germany
| | - Sebastian Kreuz
- Research Beyond Borders, Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach an der Riss, Germany
| | - Matthias Klugmann
- Research Beyond Borders, Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach an der Riss, Germany
| | - Frederik H. Igney
- Cancer Immunology and Immune Modulation, Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach an der Riss, Germany
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2
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Mansouri M, Fussenegger M. Small-Molecule Regulators for Gene Switches to Program Mammalian Cell Behaviour. Chembiochem 2024; 25:e202300717. [PMID: 38081780 DOI: 10.1002/cbic.202300717] [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: 10/18/2023] [Revised: 12/11/2023] [Indexed: 01/13/2024]
Abstract
Synthetic or natural small molecules have been extensively employed as trigger signals or inducers to regulate engineered gene circuits introduced into living cells in order to obtain desired outputs in a controlled and predictable manner. Here, we provide an overview of small molecules used to drive synthetic-biology-based gene circuits in mammalian cells, together with examples of applications at different levels of control, including regulation of DNA manipulation, RNA synthesis and editing, and protein synthesis, maturation, and trafficking. We also discuss the therapeutic potential of these small-molecule-responsive gene circuits, focusing on the advantages and disadvantages of using small molecules as triggers, the mechanisms involved, and the requirements for selecting suitable molecules, including efficiency, specificity, orthogonality, and safety. Finally, we explore potential future directions for translation of these devices to clinical medicine.
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Affiliation(s)
- Maysam Mansouri
- ETH Zurich, Department of Biosystems Science and Engineering, Klingelbergstrasse 48, CH-4056, Basel, Switzerland
| | - Martin Fussenegger
- ETH Zurich, Department of Biosystems Science and Engineering, Klingelbergstrasse 48, CH-4056, Basel, Switzerland
- University of Basel, Faculty of Science, Klingelbergstrasse 48, CH-4056, Basel, Switzerland
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3
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Teixeira AP, Fussenegger M. Synthetic Gene Circuits for Regulation of Next-Generation Cell-Based Therapeutics. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2024; 11:e2309088. [PMID: 38126677 PMCID: PMC10885662 DOI: 10.1002/advs.202309088] [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: 11/24/2023] [Indexed: 12/23/2023]
Abstract
Arming human cells with synthetic gene circuits enables to expand their capacity to execute superior sensing and response actions, offering tremendous potential for innovative cellular therapeutics. This can be achieved by assembling components from an ever-expanding molecular toolkit, incorporating switches based on transcriptional, translational, or post-translational control mechanisms. This review provides examples from the three classes of switches, and discusses their advantages and limitations to regulate the activity of therapeutic cells in vivo. Genetic switches designed to recognize internal disease-associated signals often encode intricate actuation programs that orchestrate a reduction in the sensed signal, establishing a closed-loop architecture. Conversely, switches engineered to detect external molecular or physical cues operate in an open-loop fashion, switching on or off upon signal exposure. The integration of such synthetic gene circuits into the next generation of chimeric antigen receptor T-cells is already enabling precise calibration of immune responses in terms of magnitude and timing, thereby improving the potency and safety of therapeutic cells. Furthermore, pre-clinical engineered cells targeting other chronic diseases are gathering increasing attention, and this review discusses the path forward for achieving clinical success. With synthetic biology at the forefront, cellular therapeutics holds great promise for groundbreaking treatments.
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Affiliation(s)
- Ana P. Teixeira
- Department of Biosystems Science and EngineeringETH ZurichKlingelbergstrasse 48BaselCH‐4056Switzerland
| | - Martin Fussenegger
- Department of Biosystems Science and EngineeringETH ZurichKlingelbergstrasse 48BaselCH‐4056Switzerland
- Faculty of ScienceUniversity of BaselKlingelbergstrasse 48BaselCH‐4056Switzerland
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4
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Takahashi K, Galloway KE. RNA-based controllers for engineering gene and cell therapies. Curr Opin Biotechnol 2024; 85:103026. [PMID: 38052131 DOI: 10.1016/j.copbio.2023.103026] [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: 10/02/2023] [Revised: 11/12/2023] [Accepted: 11/14/2023] [Indexed: 12/07/2023]
Abstract
Engineered RNA-based genetic controllers provide compact, tunable, post-transcriptional gene regulation. As RNA devices are generally small, these devices are portable to DNA and RNA viral vectors. RNA tools have recently expanded to allow reading and editing of endogenous RNAs for profiling and programming of transcriptional states. With their expanded capabilities and highly compact, modular, and programmable nature, RNA-based controllers will support greater safety, efficacy, and performance in gene and cell-based therapies. In this review, we highlight RNA-based controllers and their potential as user-guided and autonomous systems for control of gene and cell-based therapies.
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Affiliation(s)
- Kei Takahashi
- Department of Chemical Engineering, MIT, 25 Ames St., Cambridge, MA 02139, USA
| | - Kate E Galloway
- Department of Chemical Engineering, MIT, 25 Ames St., Cambridge, MA 02139, USA.
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5
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Luo L, Jea JDY, Wang Y, Chao PW, Yen L. Control of mammalian gene expression by modulation of polyA signal cleavage at 5' UTR. Nat Biotechnol 2024:10.1038/s41587-023-01989-0. [PMID: 38168982 DOI: 10.1038/s41587-023-01989-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Accepted: 09/13/2023] [Indexed: 01/05/2024]
Abstract
The ability to control gene expression in mammalian cells is crucial for safe and efficacious gene therapies and for elucidating gene functions. Current gene regulation systems have limitations such as harmful immune responses or low efficiency. We describe the pA regulator, an RNA-based switch that controls mammalian gene expression through modulation of a synthetic polyA signal (PAS) cleavage introduced into the 5' UTR of a transgene. The cleavage is modulated by a 'dual-mechanism'-(1) aptamer clamping to inhibit PAS cleavage and (2) drug-induced alternative splicing that removes the PAS, both activated by drug binding. This RNA-based methodology circumvents the immune responses observed in other systems and achieves a 900-fold induction with an EC50 of 0.5 µg ml-1 tetracycline (Tc), which is well within the FDA-approved dose range. The pA regulator effectively controls the luciferase transgene in live mice and the endogenous CD133 gene in human cells, in a dose-dependent and reversible manner with long-term stability.
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Affiliation(s)
- Liming Luo
- Department of Pathology & Immunology, Baylor College of Medicine, Houston, TX, USA
- Department of Molecular & Cellular Biology, Baylor College of Medicine, Houston, TX, USA
- Dan L. Duncan Cancer Center, Baylor College of Medicine, Houston, TX, USA
| | - Jocelyn Duen-Ya Jea
- Department of Pathology & Immunology, Baylor College of Medicine, Houston, TX, USA
- Department of Molecular & Cellular Biology, Baylor College of Medicine, Houston, TX, USA
- Dan L. Duncan Cancer Center, Baylor College of Medicine, Houston, TX, USA
| | - Yan Wang
- Department of Pathology & Immunology, Baylor College of Medicine, Houston, TX, USA
- Department of Molecular & Cellular Biology, Baylor College of Medicine, Houston, TX, USA
- Dan L. Duncan Cancer Center, Baylor College of Medicine, Houston, TX, USA
| | - Pei-Wen Chao
- Department of Pathology & Immunology, Baylor College of Medicine, Houston, TX, USA
- Department of Molecular & Cellular Biology, Baylor College of Medicine, Houston, TX, USA
- Dan L. Duncan Cancer Center, Baylor College of Medicine, Houston, TX, USA
| | - Laising Yen
- Department of Pathology & Immunology, Baylor College of Medicine, Houston, TX, USA.
- Department of Molecular & Cellular Biology, Baylor College of Medicine, Houston, TX, USA.
- Dan L. Duncan Cancer Center, Baylor College of Medicine, Houston, TX, USA.
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6
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Haddad-Mashadrizeh A, Mirahmadi M, Taghavizadeh Yazdi ME, Gholampour-Faroji N, Bahrami A, Zomorodipour A, Moghadam Matin M, Qayoomian M, Saebnia N. Introns and Their Therapeutic Applications in Biomedical Researches. IRANIAN JOURNAL OF BIOTECHNOLOGY 2023; 21:e3316. [PMID: 38269198 PMCID: PMC10804063 DOI: 10.30498/ijb.2023.334488.3316] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Accepted: 03/23/2023] [Indexed: 01/26/2024]
Abstract
Context Although for a long time, it was thought that intervening sequences (introns) were junk DNA without any function, their critical roles and the underlying molecular mechanisms in genome regulation have only recently come to light. Introns not only carry information for splicing, but they also play many supportive roles in gene regulation at different levels. They are supposed to function as useful tools in various biological processes, particularly in the diagnosis and treatment of diseases. Introns can contribute to numerous biological processes, including gene silencing, gene imprinting, transcription, mRNA metabolism, mRNA nuclear export, mRNA localization, mRNA surveillance, RNA editing, NMD, translation, protein stability, ribosome biogenesis, cell growth, embryonic development, apoptosis, molecular evolution, genome expansion, and proteome diversity through various mechanisms. Evidence Acquisition In order to fulfill the objectives of this study, the following databases were searched: Medline, Scopus, Web of Science, EBSCO, Open Access Journals, and Google Scholar. Only articles published in English were included. Results & Conclusions The intervening sequences of eukaryotic genes have critical functions in genome regulation, as well as in molecular evolution. Here, we summarize recent advances in our understanding of how introns influence genome regulation, as well as their effects on molecular evolution. Moreover, therapeutic strategies based on intron sequences are discussed. According to the obtained results, a thorough understanding of intron functional mechanisms could lead to new opportunities in disease diagnosis and therapies, as well as in biotechnology applications.
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Affiliation(s)
- Aliakbar Haddad-Mashadrizeh
- Industrial Biotechnology Research Group, Institute of Biotechnology, Ferdowsi University of Mashhad, Mashhad, Iran
| | - Mahdi Mirahmadi
- Stem Cell and Regenerative Medicine Research Group, Iranian Academic Center for Education, Culture and Research (ACECR), Khorasan Razavi Branch, Mashhad, Iran
- Biotechnology Research Center, Pharmaceutical Technology Institute, Mashhad University of Medical Sciences, Mashhad, Iran
| | | | - Nazanin Gholampour-Faroji
- Industrial Biotechnology Research Group, Institute of Biotechnology, Ferdowsi University of Mashhad, Mashhad, Iran
| | - Ahmadreza Bahrami
- Industrial Biotechnology Research Group, Institute of Biotechnology, Ferdowsi University of Mashhad, Mashhad, Iran
- Department of Biology, Faculty of Science, Ferdowsi University of Mashhad, Mashhad, Iran
| | | | - Maryam Moghadam Matin
- Department of Biology, Faculty of Science, Ferdowsi University of Mashhad, Mashhad, Iran
| | - Mohsen Qayoomian
- Applied Biomedical Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Neda Saebnia
- Department of Biology, Faculty of Science, Ferdowsi University of Mashhad, Mashhad, Iran
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7
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Kukhtar D, Fussenegger M. Synthetic biology in multicellular organisms: Opportunities in nematodes. Biotechnol Bioeng 2023. [PMID: 37448225 DOI: 10.1002/bit.28497] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2023] [Revised: 04/27/2023] [Accepted: 07/05/2023] [Indexed: 07/15/2023]
Abstract
Synthetic biology has mainly focused on introducing new or altered functionality in single cell systems: primarily bacteria, yeast, or mammalian cells. Here, we describe the extension of synthetic biology to nematodes, in particular the well-studied model organism Caenorhabditis elegans, as a convenient platform for developing applications in a multicellular setting. We review transgenesis techniques for nematodes, as well as the application of synthetic biology principles to construct nematode gene switches and genetic devices to control motility. Finally, we discuss potential applications of engineered nematodes.
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Affiliation(s)
- Dmytro Kukhtar
- Department of Biosystems Science and Engineering, ETH Zürich, Basel, Switzerland
| | - Martin Fussenegger
- Department of Biosystems Science and Engineering, ETH Zürich, Basel, Switzerland
- Faculty of Life Science, University of Basel, Basel, Switzerland
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8
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Mohsen MG, Midy MK, Balaji A, Breaker R. Exploiting natural riboswitches for aptamer engineering and validation. Nucleic Acids Res 2023; 51:966-981. [PMID: 36617976 PMCID: PMC9881172 DOI: 10.1093/nar/gkac1218] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2022] [Revised: 11/04/2022] [Accepted: 12/09/2022] [Indexed: 01/10/2023] Open
Abstract
Over the past three decades, researchers have found that some engineered aptamers can be made to work well in test tubes but that these same aptamers might fail to function in cells. To help address this problem, we developed the 'Graftamer' approach, an experimental platform that exploits the architecture of a natural riboswitch to enhance in vitro aptamer selection and accelerate in vivo testing. Starting with combinatorial RNA pools that contain structural features of a guanine riboswitch aptamer interspersed with regions of random sequence, we performed multiplexed in vitro selection with a collection of small molecules. This effort yielded aptamers for quinine, guanine, and caffeine that appear to maintain structural features of the natural guanine riboswitch aptamer. Quinine and caffeine aptamers were each grafted onto a natural guanine riboswitch expression platform and reporter gene expression was monitored to determine that these aptamers function in cells. Additionally, we determined the secondary structure features and survival mechanism of a class of RNA sequences that evade the intended selection strategy, providing insight into improving this approach for future efforts. These results demonstrate that the Graftamer strategy described herein represents a convenient and straightforward approach to develop aptamers and validate their in vivo function.
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Affiliation(s)
- Michael G Mohsen
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT 06511, USA,Howard Hughes Medical Institute, Yale University, New Haven, CT 06511, USA
| | - Matthew K Midy
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06511, USA
| | - Aparaajita Balaji
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT 06511, USA
| | - Ronald R Breaker
- To whom correspondence should be addressed. Tel: +1 203 432 9389; Fax: +1 203 432 6161;
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9
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Kelvin D, Suess B. Tapping the potential of synthetic riboswitches: reviewing the versatility of the tetracycline aptamer. RNA Biol 2023; 20:457-468. [PMID: 37459466 DOI: 10.1080/15476286.2023.2234732] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Revised: 06/22/2023] [Accepted: 06/23/2023] [Indexed: 07/20/2023] Open
Abstract
Synthetic riboswitches are a versatile class of regulatory elements that are becoming increasingly established in synthetic biology applications. They are characterized by their compact size and independence from auxiliary protein factors. While naturally occurring riboswitches were mostly discovered in bacteria, synthetic riboswitches have been designed for all domains of life. Published design strategies far exceed the number of riboswitches found in nature. A core element of any riboswitch is a binding domain, called an aptamer, which is characterized by high specificity and affinity for its ligand. Aptamers can be selected de novo, allowing the design of synthetic riboswitches against a broad spectrum of targets. The tetracycline aptamer has proven to be well suited for riboswitch engineering. Since its selection, it has been used in a variety of applications and is considered to be well established and characterized. Using the tetracycline aptamer as an example, we aim to discuss a large variety of design approaches for synthetic riboswitch engineering and their application. We aim to demonstrate the versatility of riboswitches in general and the high potential of synthetic RNA devices for creating new solutions in both the scientific and medical fields.
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Affiliation(s)
- Daniel Kelvin
- Fachbereich Biologie, TU Darmstadt, Darmstadt, Germany
| | - Beatrix Suess
- Fachbereich Biologie, TU Darmstadt, Darmstadt, Germany
- Centre for Synthetic Biology, TU Darmstadt, Darmstadt, Germany
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10
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Lennon SR, Batey RT. Regulation of Gene Expression Through Effector-dependent Conformational Switching by Cobalamin Riboswitches. J Mol Biol 2022; 434:167585. [PMID: 35427633 PMCID: PMC9474592 DOI: 10.1016/j.jmb.2022.167585] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2022] [Revised: 04/04/2022] [Accepted: 04/06/2022] [Indexed: 11/16/2022]
Abstract
Riboswitches are an outstanding example of genetic regulation mediated by RNA conformational switching. In these non-coding RNA elements, the occupancy status of a ligand-binding domain governs the mRNA's decision to form one of two mutually exclusive structures in the downstream expression platform. Temporal constraints upon the function of many riboswitches, requiring folding of complex architectures and conformational switching in a limited co-transcriptional timeframe, make them ideal model systems for studying these processes. In this review, we focus on the mechanism of ligand-directed conformational changes in one of the most widely distributed riboswitches in bacteria: the cobalamin family. We describe the architectural features of cobalamin riboswitches whose structures have been determined by x-ray crystallography, which suggest a direct physical role of cobalamin in effecting the regulatory switch. Next, we discuss a series of experimental approaches applied to several model cobalamin riboswitches that interrogate these structural models. As folding is central to riboswitch function, we consider the differences in folding landscapes experienced by RNAs that are produced in vitro and those that are allowed to fold co-transcriptionally. Finally, we highlight a set of studies that reveal the difficulties of studying cobalamin riboswitches outside the context of transcription and that co-transcriptional approaches are essential for developing a more accurate picture of their structure-function relationships in these switches. This understanding will be essential for future advancements in the use of small-molecule guided RNA switches in a range of applications such as biosensors, RNA imaging tools, and nucleic acid-based therapies.
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Affiliation(s)
- Shelby R Lennon
- Department of Biochemistry, University of Colorado, Boulder, CO 80309-0596, USA
| | - Robert T Batey
- Department of Biochemistry, University of Colorado, Boulder, CO 80309-0596, USA.
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11
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Lu Q, Hu Y, Yin Li C, Kuang Y. Aptamer‐Array‐Guided Protein Assembly Enhances Synthetic mRNA Switch Performance. Angew Chem Int Ed Engl 2022; 61:e202207319. [PMID: 35703374 PMCID: PMC9544043 DOI: 10.1002/anie.202207319] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Indexed: 11/17/2022]
Abstract
Synthetic messenger RNA (mRNA) switches are powerful synthetic biological tools that can sense cellular molecules to manipulate cell fate. However, their performances are limited by high output signal noise due to leaky output protein expression. Here, we designed a readout control module that disables protein leakage from generating signal. Aptamer array on the switch guides the inactive output protein to self‐assemble into functional assemblies that generate output signal. Leaky protein expression fails to saturate the array, thus produces marginal signal. In this study, we demonstrated that switches with this module exhibit substantially lower signal noise and, consequently, higher input sensitivity and wider output range. Such switches are applicable for different types of input molecules and output proteins. The work here demonstrates a new type of spatially guided protein self‐assembly, affording novel synthetic mRNA switches that promise accurate cell manipulation for biomedical applications.
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Affiliation(s)
- Qiuyu Lu
- Department of Chemical and Biological Engineering The Hong Kong University of Science and Technology Clear Water Bay, Kowloon, Hong Kong Hong Kong
| | - Yaxin Hu
- Department of Chemical and Biological Engineering The Hong Kong University of Science and Technology Clear Water Bay, Kowloon, Hong Kong Hong Kong
| | - Cheuk Yin Li
- Department of Chemical and Biological Engineering The Hong Kong University of Science and Technology Clear Water Bay, Kowloon, Hong Kong Hong Kong
| | - Yi Kuang
- Department of Chemical and Biological Engineering The Hong Kong University of Science and Technology Clear Water Bay, Kowloon, Hong Kong Hong Kong
- HKUST Shenzhen Research Institute Shenzhen Guangdong China
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12
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Lu Q, Hu Y, Li CY, Kuang Y. Aptamer‐Array‐Guided Protein Assembly Enhances Synthetic mRNA Switch Performance. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202207319] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Qiuyu Lu
- Hong Kong University of Science and Technology School of Engineering Chemical and Biological Engineering HONG KONG
| | - Yaxin Hu
- Hong Kong University of Science and Technology School of Engineering Chemical and Biological Engineering HONG KONG
| | - Cheuk Yin Li
- Hong Kong University of Science and Technology School of Engineering Chemical and Biological Engineering HONG KONG
| | - Yi Kuang
- Hong Kong University of Science and Technology Chemical and Biological Engineering Room 5578, Academic Bldg,Clear Water Bay 000000 Kowloon HONG KONG
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13
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Hoetzel J, Suess B. Structural changes in aptamers are essential for synthetic riboswitch engineering. J Mol Biol 2022; 434:167631. [PMID: 35595164 DOI: 10.1016/j.jmb.2022.167631] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Revised: 05/05/2022] [Accepted: 05/07/2022] [Indexed: 11/19/2022]
Abstract
Synthetic riboswitches are powerful tools in synthetic biology in which sensing and execution are consolidated in a single RNA molecule. By using SELEX to select aptamers in vitro, synthetic riboswitches can in theory be engineered against any ligand of choice. Surprisingly, very few in vitro selected aptamers have been used for the engineering of synthetic riboswitches. In-depth studies of these aptamers suggest that the key characteristics of such regulatory active RNAs are their structural switching abilities and their binding dynamics. Conventional SELEX approaches seem to be inadequate to select for these characteristics, which may explain the lack of in vitro selected aptamers suited for engineering of synthetic riboswitches. In this review, we explore the functional principles of synthetic riboswitches, identify key characteristics of regulatory active in vitro selected aptamers and integrate these findings in context with available in vitro selection methods. Based on these insights, we propose to use a combination of capture-SELEX and subsequent functional screening for a more successful in vitro selection of aptamers that can be applied for the engineering of synthetic riboswitches.
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Affiliation(s)
- Janis Hoetzel
- Department of Biology, Technical University of Darmstadt, Schnittspahnstraße 10, D-64287 Darmstadt, Germany. https://www.twitter.com/J_Hoetzel
| | - Beatrix Suess
- Department of Biology, Technical University of Darmstadt, Schnittspahnstraße 10, D-64287 Darmstadt, Germany; Center for Synthetic Biology, Technical University of Darmstadt, Germany.
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14
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Tickner ZJ, Farzan M. Riboswitches for Controlled Expression of Therapeutic Transgenes Delivered by Adeno-Associated Viral Vectors. Pharmaceuticals (Basel) 2021; 14:ph14060554. [PMID: 34200913 PMCID: PMC8230432 DOI: 10.3390/ph14060554] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2021] [Revised: 05/28/2021] [Accepted: 06/04/2021] [Indexed: 11/16/2022] Open
Abstract
Vectors developed from adeno-associated virus (AAV) are powerful tools for in vivo transgene delivery in both humans and animal models, and several AAV-delivered gene therapies are currently approved for clinical use. However, AAV-mediated gene therapy still faces several challenges, including limited vector packaging capacity and the need for a safe, effective method for controlling transgene expression during and after delivery. Riboswitches, RNA elements which control gene expression in response to ligand binding, are attractive candidates for regulating expression of AAV-delivered transgene therapeutics because of their small genomic footprints and non-immunogenicity compared to protein-based expression control systems. In addition, the ligand-sensing aptamer domains of many riboswitches can be exchanged in a modular fashion to allow regulation by a variety of small molecules, proteins, and oligonucleotides. Riboswitches have been used to regulate AAV-delivered transgene therapeutics in animal models, and recently developed screening and selection methods allow rapid isolation of riboswitches with novel ligands and improved performance in mammalian cells. This review discusses the advantages of riboswitches in the context of AAV-delivered gene therapy, the subsets of riboswitch mechanisms which have been shown to function in human cells and animal models, recent progress in riboswitch isolation and optimization, and several examples of AAV-delivered therapeutic systems which might be improved by riboswitch regulation.
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Affiliation(s)
- Zachary J. Tickner
- Department of Immunology and Microbiology, the Scripps Research Institute, Jupiter, FL 33458, USA;
- Correspondence:
| | - Michael Farzan
- Department of Immunology and Microbiology, the Scripps Research Institute, Jupiter, FL 33458, USA;
- Emmune, Inc., Jupiter, FL 33458, USA
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