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Liu Y, Wang J, Wu Y, Wang Y. Advancing the enzymatic toolkit for 2'-fluoro arabino nucleic acid (FANA) manipulation: phosphorylation, ligation, replication, and templating RNA transcription. Chem Sci 2024; 15:12534-12542. [PMID: 39118620 PMCID: PMC11304824 DOI: 10.1039/d4sc02904f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2024] [Accepted: 06/17/2024] [Indexed: 08/10/2024] Open
Abstract
2'-Fluoro arabino nucleic acid (FANA), classified as a xeno nucleic acid (XNA), stands as a prominent subject of investigation in synthetic genetic polymers. Demonstrating efficacy as antisense oligonucleotides (ASOs) and exhibiting the ability to fold into functional structures akin to enzymes and aptamers, FANA holds substantial promise across diverse biological and therapeutic domains. Owing to structural similarities to DNA, the utilization of naturally occurring DNA polymerases for DNA-mediated FANA replication is well-documented. In this study, we explore alternative nucleic acid processing enzymes typically employed for DNA oligonucleotide (ON) phosphorylation, ligation, and amplification, and assess their compatibility with FANA substrates. Notably, T4 polynucleotide kinase (T4 PNK) efficiently phosphorylated the 5'-hydroxyl group of FANA using ATP as a phosphate donor. Subsequent ligation of the phosphorylated FANA with an upstream FANA ON was achieved with T4 DNA ligase, facilitated by a DNA splint ON that brings the two FANA ONs into proximity. This methodology enabled the reconstruction of RNA-cleaving FANA 12-7 by ligating two FANA fragments amenable to solid-phase synthesis. Furthermore, Tgo DNA polymerase, devoid of 3' to 5' exonuclease activity [Tgo (exo-)], demonstrated proficiency in performing polymerase chain reaction (PCR) with a mixture of dNTPs and FANA NTPs (fNTPs), yielding DNA-FANA chimeras with efficiency and fidelity comparable to traditional DNA PCR. Notably, T7 RNA polymerase (T7 RNAP) exhibited recognition of double-stranded fA-DNA chimeras containing T7 promoter sequences, enabling in vitro transcription of RNA molecules up to 649 nt in length, even in the presence of highly structured F30 motifs at the 3' end. Our findings significantly expand the enzymatic toolkit for FANA manipulation, encompassing phosphorylation, ligation, chimeric amplification, and templating T7 RNAP-catalyzed RNA transcription. These advancements are poised to expedite fundamental research, functional evolution, and translational applications of FANA-based XNA agents. They also have the potential to inspire explorations of a broader range of non-natural nucleic acids that can be routinely studied in laboratories, ultimately expanding the repertoire of nucleic acid-based biomedicine and biotechnology.
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Affiliation(s)
- Yingyu Liu
- College of Pharmaceutical Sciences, Soochow University Suzhou 215123 China
- Hangzhou Institute of Medicine (HIM), Chinese Academy of Sciences Hangzhou Zhejiang 310000 China
| | - Jun Wang
- College of Pharmaceutical Sciences, Soochow University Suzhou 215123 China
- Hangzhou Institute of Medicine (HIM), Chinese Academy of Sciences Hangzhou Zhejiang 310000 China
| | - Yashu Wu
- Hangzhou Institute of Medicine (HIM), Chinese Academy of Sciences Hangzhou Zhejiang 310000 China
- The Cancer Hospital of the University of Chinese Academy of Science (Zhejiang Cancer Hospital) Hangzhou Zhejiang 310022 China
| | - Yajun Wang
- Hangzhou Institute of Medicine (HIM), Chinese Academy of Sciences Hangzhou Zhejiang 310000 China
- The Cancer Hospital of the University of Chinese Academy of Science (Zhejiang Cancer Hospital) Hangzhou Zhejiang 310022 China
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Razi N, Li W, Ignacio MA, Loube JM, Agostino EL, Zhu X, Scull MA, DeStefano JJ. Inhibition of SARS-CoV-2 infection in human airway epithelium with a xeno-nucleic acid aptamer. Respir Res 2023; 24:272. [PMID: 37932762 PMCID: PMC10629106 DOI: 10.1186/s12931-023-02590-4] [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: 09/29/2023] [Accepted: 10/30/2023] [Indexed: 11/08/2023] Open
Abstract
BACKGROUND SARS-CoV-2, the agent responsible for the COVID-19 pandemic, enters cells through viral spike glycoprotein binding to the cellular receptor, angiotensin-converting enzyme 2 (ACE2). Given the lack of effective antivirals targeting SARS-CoV-2, we previously utilized systematic evolution of ligands by exponential enrichment (SELEX) and selected fluoro-arabino nucleic acid (FANA) aptamer R8-9 that was able to block the interaction between the viral receptor-binding domain and ACE2. METHODS Here, we further assessed FANA-R8-9 as an entry inhibitor in contexts that recapitulate infection in vivo. RESULTS We demonstrate that FANA-R8-9 inhibits spike-bearing pseudovirus particle uptake in cell lines. Then, using an in-vitro model of human airway epithelium (HAE) and SARS-CoV-2 virus, we show that FANA-R8-9 significantly reduces viral infection when added either at the time of inoculation, or several hours later. These results were specific to the R8-9 sequence, not the xeno-nucleic acid utilized to make the aptamer. Importantly, we also show that FANA-R8-9 is stable in HAE culture secretions and has no overt cytotoxic effects. CONCLUSIONS Together, these results suggest that FANA-R8-9 effectively prevents infection by specific SARS-CoV-2 variants and indicate that aptamer technology could be utilized to target other clinically-relevant viruses in the respiratory mucosa.
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Affiliation(s)
- Niayesh Razi
- Department of Cell Biology and Molecular Genetics, Maryland Pathogen Research Institute (MPRI), University of Maryland, College Park, MD, 20742, USA
| | - Weizhong Li
- Division of Immunology, Virginia-Maryland College of Veterinary Medicine, University of Maryland, College Park, MD, 20742, USA
| | - Maxinne A Ignacio
- Department of Cell Biology and Molecular Genetics, Maryland Pathogen Research Institute (MPRI), University of Maryland, College Park, MD, 20742, USA
| | - Jeffrey M Loube
- Department of Cell Biology and Molecular Genetics, Maryland Pathogen Research Institute (MPRI), University of Maryland, College Park, MD, 20742, USA
| | - Eva L Agostino
- Department of Cell Biology and Molecular Genetics, Maryland Pathogen Research Institute (MPRI), University of Maryland, College Park, MD, 20742, USA
| | - Xiaoping Zhu
- Division of Immunology, Virginia-Maryland College of Veterinary Medicine, University of Maryland, College Park, MD, 20742, USA
| | - Margaret A Scull
- Department of Cell Biology and Molecular Genetics, Maryland Pathogen Research Institute (MPRI), University of Maryland, College Park, MD, 20742, USA.
| | - Jeffrey J DeStefano
- Department of Cell Biology and Molecular Genetics, Maryland Pathogen Research Institute (MPRI), University of Maryland, College Park, MD, 20742, USA.
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3
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Razi N, Li W, Ignacio MA, Loube JM, Agostino EL, Zhu X, Scull MA, DeStefano JJ. Inhibition of SARS-CoV-2 Infection in Human Airway Epithelium with a Xeno-Nucleic Acid Aptamer. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.09.27.559799. [PMID: 37808754 PMCID: PMC10557761 DOI: 10.1101/2023.09.27.559799] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/10/2023]
Abstract
Background SARS-CoV-2, the agent responsible for the COVID-19 pandemic, enters cells through viral spike glycoprotein binding to the cellular receptor, angiotensin-converting enzyme 2 (ACE2). Given the lack of effective antivirals targeting SARS-CoV-2, we previously utilized systematic evolution of ligands by exponential enrichment (SELEX) and selected fluoro-arabino nucleic acid (FANA) aptamer R8-9 that was able to block the interaction between the viral receptor-binding domain and ACE2. Methods Here, we further assessed FANA-R8-9 as an entry inhibitor in contexts that recapitulate infection in vivo. Results We demonstrate that FANA-R8-9 inhibits spike-bearing pseudovirus particle uptake in cell lines. Then, using an in-vitro model of human airway epithelium (HAE) and SARS-CoV-2 virus, we show that FANA-R8-9 significantly reduces viral infection when added either at the time of inoculation, or several hours later. These results were specific to the R8-9 sequence, not the xeno-nucleic acid utilized to make the aptamer. Importantly, we also show that FANA-R8-9 is stable in HAE culture secretions and has no overt cytotoxic effects. Conclusions Together, these results suggest that FANA-R8-9 effectively prevents infection by specific SARS-CoV-2 variants and indicate that aptamer technology could be utilized to target other clinically-relevant viruses in the respiratory mucosa.
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Affiliation(s)
- Niayesh Razi
- Department of Cell Biology and Molecular Genetics, and Maryland Pathogen Research Institute (MPRI), University of Maryland, College Park, MD, 20742
| | - Weizhong Li
- Division of Immunology, Virginia-Maryland College of Veterinary Medicine, University of Maryland, College Park, MD, 20742
| | - Maxinne A. Ignacio
- Department of Cell Biology and Molecular Genetics, and Maryland Pathogen Research Institute (MPRI), University of Maryland, College Park, MD, 20742
| | - Jeffrey M. Loube
- Department of Cell Biology and Molecular Genetics, and Maryland Pathogen Research Institute (MPRI), University of Maryland, College Park, MD, 20742
| | - Eva L. Agostino
- Department of Cell Biology and Molecular Genetics, and Maryland Pathogen Research Institute (MPRI), University of Maryland, College Park, MD, 20742
| | - Xiaoping Zhu
- Division of Immunology, Virginia-Maryland College of Veterinary Medicine, University of Maryland, College Park, MD, 20742
| | - Margaret A. Scull
- Department of Cell Biology and Molecular Genetics, and Maryland Pathogen Research Institute (MPRI), University of Maryland, College Park, MD, 20742
| | - Jeffrey J. DeStefano
- Department of Cell Biology and Molecular Genetics, and Maryland Pathogen Research Institute (MPRI), University of Maryland, College Park, MD, 20742
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4
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Chen MJ, Gatignol A, Scarborough RJ. The discovery and development of RNA-based therapies for treatment of HIV-1 infection. Expert Opin Drug Discov 2023; 18:163-179. [PMID: 36004505 DOI: 10.1080/17460441.2022.2117296] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
INTRODUCTION Long-term control of HIV-1 infection can potentially be achieved using autologous stem cell transplants with gene-modified cells. Non-coding RNAs represent a diverse class of therapeutic agents including ribozymes, RNA aptamers and decoys, small interfering RNAs, short hairpin RNAs, and U1 interference RNAs that can be designed to inhibit HIV-1 replication. They have been engineered for delivery as drugs to complement current HIV-1 therapies and as gene therapies for a potential HIV-1 functional cure. AREAS COVERED This review surveys the past three decades of development of these RNA technologies with a focus on their efficacy and safety for treating HIV-1 infections. We describe the mechanisms of each RNA-based agent, targets they have been developed against, efforts to enhance their stability and efficacy, and we evaluate their performance in past and ongoing preclinical and clinical trials. EXPERT OPINION RNA-based technologies are among the top candidates for gene therapies where they can be stably expressed for long-term suppression of HIV-1. Advances in both gene and drug delivery strategies and improvements to non-coding RNA stability and antiviral properties will cooperatively drive forward progress in improving drug therapy and engineering HIV-1 resistant cells.
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Affiliation(s)
- Michelle J Chen
- Lady Davis Institute for Medical Research, Montréal, Québec, Canada.,Department of Medicine, Division of Experimental Medicine, McGill University, Montréal, Québec, Canada
| | - Anne Gatignol
- Lady Davis Institute for Medical Research, Montréal, Québec, Canada.,Department of Medicine, Division of Experimental Medicine, McGill University, Montréal, Québec, Canada.,Department of Microbiology and Immunology, McGill University, Montréal, Québec, Canada
| | - Robert J Scarborough
- Lady Davis Institute for Medical Research, Montréal, Québec, Canada.,Department of Microbiology and Immunology, McGill University, Montréal, Québec, Canada
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5
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Chen Z, Luo H, Gubu A, Yu S, Zhang H, Dai H, Zhang Y, Zhang B, Ma Y, Lu A, Zhang G. Chemically modified aptamers for improving binding affinity to the target proteins via enhanced non-covalent bonding. Front Cell Dev Biol 2023; 11:1091809. [PMID: 36910146 PMCID: PMC9996316 DOI: 10.3389/fcell.2023.1091809] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Accepted: 02/15/2023] [Indexed: 02/25/2023] Open
Abstract
Nucleic acid aptamers are ssDNA or ssRNA fragments that specifically recognize targets. However, the pharmacodynamic properties of natural aptamers consisting of 4 naturally occurring nucleosides (A, G, C, T/U) are generally restricted for inferior binding affinity than the cognate antibodies. The development of high-affinity modification strategies has attracted extensive attention in aptamer applications. Chemically modified aptamers with stable three-dimensional shapes can tightly interact with the target proteins via enhanced non-covalent bonding, possibly resulting in hundreds of affinity enhancements. This review overviewed high-affinity modification strategies used in aptamers, including nucleobase modifications, fluorine modifications (2'-fluoro nucleic acid, 2'-fluoro arabino nucleic acid, 2',2'-difluoro nucleic acid), structural alteration modifications (locked nucleic acid, unlocked nucleic acid), phosphate modifications (phosphorothioates, phosphorodithioates), and extended alphabets. The review emphasized how these high-affinity modifications function in effect as the interactions with target proteins, thereby refining the pharmacodynamic properties of aptamers.
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Affiliation(s)
- Zefeng Chen
- Law Sau Fai Institute for Advancing Translational Medicine in Bone and Joint Diseases, School of Chinese Medicine, Hong Kong Baptist University, Kowloon, Hong Kong SAR, China.,Institute of Integrated Bioinfomedicine and Translational Science, School of Chinese Medicine, Hong Kong Baptist University, Kowloon, Hong Kong SAR, China
| | - Hang Luo
- Law Sau Fai Institute for Advancing Translational Medicine in Bone and Joint Diseases, School of Chinese Medicine, Hong Kong Baptist University, Kowloon, Hong Kong SAR, China.,Institute of Integrated Bioinfomedicine and Translational Science, School of Chinese Medicine, Hong Kong Baptist University, Kowloon, Hong Kong SAR, China
| | - Amu Gubu
- Law Sau Fai Institute for Advancing Translational Medicine in Bone and Joint Diseases, School of Chinese Medicine, Hong Kong Baptist University, Kowloon, Hong Kong SAR, China.,Aptacure Therapeutics Limited, Kowloon, Hong Kong SAR, China
| | - Sifan Yu
- School of Chinese Medicine, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong, Hong Kong SAR, China
| | - Huarui Zhang
- School of Chinese Medicine, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong, Hong Kong SAR, China
| | - Hong Dai
- Law Sau Fai Institute for Advancing Translational Medicine in Bone and Joint Diseases, School of Chinese Medicine, Hong Kong Baptist University, Kowloon, Hong Kong SAR, China.,Institute of Integrated Bioinfomedicine and Translational Science, School of Chinese Medicine, Hong Kong Baptist University, Kowloon, Hong Kong SAR, China
| | - Yihao Zhang
- Law Sau Fai Institute for Advancing Translational Medicine in Bone and Joint Diseases, School of Chinese Medicine, Hong Kong Baptist University, Kowloon, Hong Kong SAR, China
| | - Baoting Zhang
- School of Chinese Medicine, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong, Hong Kong SAR, China
| | - Yuan Ma
- Law Sau Fai Institute for Advancing Translational Medicine in Bone and Joint Diseases, School of Chinese Medicine, Hong Kong Baptist University, Kowloon, Hong Kong SAR, China.,Institute of Integrated Bioinfomedicine and Translational Science, School of Chinese Medicine, Hong Kong Baptist University, Kowloon, Hong Kong SAR, China.,Institute of Precision Medicine and Innovative Drug Discovery, HKBU Institute for Research and Continuing Education, Shenzhen, Hong Kong SAR, China
| | - Aiping Lu
- Law Sau Fai Institute for Advancing Translational Medicine in Bone and Joint Diseases, School of Chinese Medicine, Hong Kong Baptist University, Kowloon, Hong Kong SAR, China.,Institute of Integrated Bioinfomedicine and Translational Science, School of Chinese Medicine, Hong Kong Baptist University, Kowloon, Hong Kong SAR, China.,Institute of Precision Medicine and Innovative Drug Discovery, HKBU Institute for Research and Continuing Education, Shenzhen, Hong Kong SAR, China
| | - Ge Zhang
- Law Sau Fai Institute for Advancing Translational Medicine in Bone and Joint Diseases, School of Chinese Medicine, Hong Kong Baptist University, Kowloon, Hong Kong SAR, China.,Institute of Integrated Bioinfomedicine and Translational Science, School of Chinese Medicine, Hong Kong Baptist University, Kowloon, Hong Kong SAR, China.,Institute of Precision Medicine and Innovative Drug Discovery, HKBU Institute for Research and Continuing Education, Shenzhen, Hong Kong SAR, China
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6
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Wang G, Du Y, Ma X, Ye F, Qin Y, Wang Y, Xiang Y, Tao R, Chen T. Thermophilic Nucleic Acid Polymerases and Their Application in Xenobiology. Int J Mol Sci 2022; 23:ijms232314969. [PMID: 36499296 PMCID: PMC9738464 DOI: 10.3390/ijms232314969] [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: 10/27/2022] [Revised: 11/22/2022] [Accepted: 11/27/2022] [Indexed: 12/02/2022] Open
Abstract
Thermophilic nucleic acid polymerases, isolated from organisms that thrive in extremely hot environments, possess great DNA/RNA synthesis activities under high temperatures. These enzymes play indispensable roles in central life activities involved in DNA replication and repair, as well as RNA transcription, and have already been widely used in bioengineering, biotechnology, and biomedicine. Xeno nucleic acids (XNAs), which are analogs of DNA/RNA with unnatural moieties, have been developed as new carriers of genetic information in the past decades, which contributed to the fast development of a field called xenobiology. The broad application of these XNA molecules in the production of novel drugs, materials, and catalysts greatly relies on the capability of enzymatic synthesis, reverse transcription, and amplification of them, which have been partially achieved with natural or artificially tailored thermophilic nucleic acid polymerases. In this review, we first systematically summarize representative thermophilic and hyperthermophilic polymerases that have been extensively studied and utilized, followed by the introduction of methods and approaches in the engineering of these polymerases for the efficient synthesis, reverse transcription, and amplification of XNAs. The application of XNAs facilitated by these polymerases and their mutants is then discussed. In the end, a perspective for the future direction of further development and application of unnatural nucleic acid polymerases is provided.
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7
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Silwal AP, Thennakoon SKS, Arya SP, Postema RM, Jahan R, Phuoc CMT, Tan X. DNA aptamers inhibit SARS-CoV-2 spike-protein binding to hACE2 by an RBD- independent or dependent approach. Theranostics 2022; 12:5522-5536. [PMID: 35910791 PMCID: PMC9330529 DOI: 10.7150/thno.74428] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Accepted: 06/23/2022] [Indexed: 11/12/2022] Open
Abstract
Objective: Nobody knows when the COVID-19 pandemic will end or when and where the next coronavirus will outbreak. Therefore, it is still necessary to develop SARS-CoV-2 inhibitors for different variants or even the new coronavirus. Since SARS-CoV-2 uses its surface spike-protein to recognize hACE2, mediating its entry into cells, ligands that can specifically recognize the spike-protein have the potential to prevent infection. Methods: We have recently discovered DNA aptamers against the S2-domain of the WT spike-protein by exploiting the selection process called SELEX. After optimization, among all candidates, the aptamer S2A2C1 has the shortest sequence and the best binding affinity toward the S2-protein. More importantly, the S2A2C1 aptamer does not bind to the RBD of the spike-protein, but it efficiently blocks the spike-protein/hACE2 interaction, suggesting an RBD-independent inhibition approach. To further improve its performance, we conjugated the S2A2C1 aptamer with a reported anti-RBD aptamer, S1B6C3, using various linkers and constructed hetero-bivalent fusion aptamers. Binding affinities of mono and fusion aptamers against the spike-proteins were measured. The inhibition efficacies of mono and fusion aptamers to prevent the hACE2/spike-protein interaction were determined using ELISA. Results: Anti-spike-protein aptamers, including S2A2C1 and S1B6C3-A5-S2A2C1, maintained high binding affinity toward the WT, Delta, and Omicron spike-proteins and high inhibition efficacies to prevent them from binding to hACE2, rendering them well-suited as diagnostic and therapeutic molecular tools to target SARS-CoV-2 and its variants. Conclusions: Overall, we discovered the anti-S2 aptamer, S2A2C1, which inhibits the hACE2/spike-protein interaction via an RBD-independent approach. The anti-S2 and anti-RBD aptamers were conjugated to obtain the fusion aptamer, S1B6C3-A5-S2A2C1, which recognizes the spike-protein by an RBD-dependent approach. Our strategies, which discovered aptamer inhibitors targeting the highly conserved S2-protein, as well as the design of fusion aptamers, can be used to target new coronaviruses as they emerge.
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Affiliation(s)
| | | | | | | | | | | | - Xiaohong Tan
- Department of Chemistry and Center for Photochemical Sciences, Bowling Green State University, Bowling Green, Ohio 43403, United States
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8
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Wu KB, Skrodzki CJA, Su Q, Lin J, Niu J. "Click handle"-modified 2'-deoxy-2'-fluoroarabino nucleic acid as a synthetic genetic polymer capable of post-polymerization functionalization. Chem Sci 2022; 13:6873-6881. [PMID: 35774169 PMCID: PMC9200136 DOI: 10.1039/d2sc00679k] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Accepted: 05/16/2022] [Indexed: 01/01/2023] Open
Abstract
The functions of natural nucleic acids such as DNA and RNA have transcended genetic information carriers and now encompass affinity reagents, molecular catalysts, nanostructures, data storage, and many others. However, the vulnerability of natural nucleic acids to nuclease degradation and the lack of chemical functionality have imposed a significant constraint on their ever-expanding applications. Herein, we report the synthesis and polymerase recognition of a 5-(octa-1,7-diynyl)uracil 2′-deoxy-2′-fluoroarabinonucleic acid (FANA) triphosphate. The DNA-templated, polymerase-mediated primer extension using this “click handle”-modified FANA (cmFANA) triphosphate and other FANA nucleotide triphosphates consisting of canonical nucleobases efficiently generated full-length products. The resulting cmFANA polymers exhibited excellent nuclease resistance and the ability to undergo efficient click conjugation with azide-functionalized molecules, thereby becoming a promising platform for serving as a programmable and evolvable synthetic genetic polymer capable of post-polymerization functionalization. Polymerase-mediated incorporation of a “click handle”-modified fluoroarabinonucleic acid (cmFANA) triphosphate produces a new class of nuclease-resistant, evolvable genetic polymers that can be functionalized with azide-containing molecules.![]()
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Affiliation(s)
- Kevin B Wu
- Department of Chemistry, Boston College 2609 Beacon Street, Chestnut Hill MA 20467 USA
| | | | - Qiwen Su
- Department of Chemistry, Boston College 2609 Beacon Street, Chestnut Hill MA 20467 USA
| | - Jennifer Lin
- Department of Chemistry, Boston College 2609 Beacon Street, Chestnut Hill MA 20467 USA
| | - Jia Niu
- Department of Chemistry, Boston College 2609 Beacon Street, Chestnut Hill MA 20467 USA
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9
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Engelman AN, Kvaratskhelia M. Multimodal Functionalities of HIV-1 Integrase. Viruses 2022; 14:926. [PMID: 35632668 PMCID: PMC9144474 DOI: 10.3390/v14050926] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Revised: 04/20/2022] [Accepted: 04/26/2022] [Indexed: 01/11/2023] Open
Abstract
Integrase is the retroviral protein responsible for integrating reverse transcripts into cellular genomes. Co-packaged with viral RNA and reverse transcriptase into capsid-encased viral cores, human immunodeficiency virus 1 (HIV-1) integrase has long been implicated in reverse transcription and virion maturation. However, the underlying mechanisms of integrase in these non-catalytic-related viral replication steps have remained elusive. Recent results have shown that integrase binds genomic RNA in virions, and that mutational or pharmacological disruption of integrase-RNA binding yields eccentric virion particles with ribonucleoprotein complexes situated outside of the capsid shell. Such viruses are defective for reverse transcription due to preferential loss of integrase and viral RNA from infected target cells. Parallel research has revealed defective integrase-RNA binding and eccentric particle formation as common features of class II integrase mutant viruses, a phenotypic grouping of viruses that display defects at steps beyond integration. In light of these new findings, we propose three new subclasses of class II mutant viruses (a, b, and c), all of which are defective for integrase-RNA binding and particle morphogenesis, but differ based on distinct underlying mechanisms exhibited by the associated integrase mutant proteins. We also assess how these findings inform the role of integrase in HIV-1 particle maturation.
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Affiliation(s)
- Alan N. Engelman
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Boston, MA 02215, USA
- Department of Medicine, Harvard Medical School, Boston, MA 02115, USA
| | - Mamuka Kvaratskhelia
- Division of Infectious Diseases, Anschutz Medical Campus, University of Colorado School of Medicine, Aurora, CO 80045, USA
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10
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Li Q, Maola VA, Chim N, Hussain J, Lozoya-Colinas A, Chaput JC. Synthesis and Polymerase Recognition of Threose Nucleic Acid Triphosphates Equipped with Diverse Chemical Functionalities. J Am Chem Soc 2021; 143:17761-17768. [PMID: 34637287 DOI: 10.1021/jacs.1c08649] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Expanding the chemical space of evolvable non-natural genetic polymers (XNAs) to include functional groups that enhance protein target binding affinity offers a promising route to therapeutic aptamers with high biological stability. Here we describe the chemical synthesis and polymerase recognition of 10 chemically diverse functional groups introduced at the C-5 position of α-l-threofuranosyl uridine nucleoside triphosphate (tUTP). We show that the set of tUTP substrates is universally recognized by the laboratory-evolved polymerase Kod-RSGA. Insights into the mechanism of TNA synthesis were obtained from a high-resolution X-ray crystal structure of the postcatalytic complex bound to the primer-template duplex. A structural analysis reveals a large cavity in the enzyme active site that can accommodate the side chain of C-5-modified tUTP substrates. Our findings expand the chemical space of evolvable nucleic acid systems by providing a synthetic route to artificial genetic polymers that are uniformly modified with diversity-enhancing functional groups.
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11
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Xeno-Nucleic Acid (XNA) 2'-Fluoro-Arabino Nucleic Acid (FANA) Aptamers to the Receptor-Binding Domain of SARS-CoV-2 S Protein Block ACE2 Binding. Viruses 2021; 13:v13101983. [PMID: 34696413 PMCID: PMC8539646 DOI: 10.3390/v13101983] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2021] [Revised: 09/27/2021] [Accepted: 09/30/2021] [Indexed: 01/03/2023] Open
Abstract
The causative agent of COVID-19, SARS-CoV-2, gains access to cells through interactions of the receptor-binding domain (RBD) on the viral S protein with angiotensin-converting enzyme 2 (ACE2) on the surface of human host cells. Systematic evolution of ligands by exponential enrichment (SELEX) was used to generate aptamers (nucleic acids selected for high binding affinity to a target) to the RBD made from 2ʹ-fluoro-arabinonucleic acid (FANA). The best selected ~79 nucleotide aptamers bound the RBD (Arg319-Phe541) and the larger S1 domain (Val16-Arg685) of the 1272 amino acid S protein with equilibrium dissociation constants (KD,app) of ~10–20 nM, and binding half-life for the RBD, S1 domain, and full trimeric S protein of 53 ± 18, 76 ± 5, and 127 ± 7 min, respectively. Aptamers inhibited the binding of the RBD to ACE2 in an ELISA assay. Inhibition, on a per weight basis, was similar to neutralizing antibodies that were specific for RBD. Aptamers demonstrated high specificity, binding with about 10-fold lower affinity to the related S1 domain from the original SARS virus, which also binds to ACE2. Overall, FANA aptamers show affinities comparable to previous DNA aptamers to RBD and S1 protein and directly block receptor interactions while using an alternative Xeno-nucleic acid (XNA) platform.
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12
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Ferreira-Bravo IA, DeStefano JJ. Xeno-nucleic Acid (XNA) 2'-Fluoro-Arabino Nucleic Acid (FANA) Aptamers to the Receptor Binding Domain of SARS-CoV-2 S Protein Block ACE2 Binding. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2021. [PMID: 34282416 DOI: 10.1101/2021.07.13.452259] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The causative agent of COVID-19, SARS-CoV-2, gains access to cells through interactions of the receptor binding domain (RBD) on the viral S protein with angiotensin converting enzyme 2 (ACE2) on the surface of human host cells. Systematic Evolution of Ligands by Exponential Enrichment (SELEX) was used to generate aptamers (nucleic acids selected for high binding affinity to a target) to the RBD made from 2'-fluoroarabinonucleic acid (FANA). The best selected ~ 79 nucleotide aptamers bound the RBD (Arg319-Phe541) and the larger S1 domain (Val16-Arg685) of the 1272 amino acid S protein with equilibrium dissociation constants ( K D,app ) of ~ 10-20 nM and a binding half-life for the RBD of 53 ± 18 minutes. Aptamers inhibited the binding of the RBD to ACE2 in an ELISA assay. Inhibition, on a per weight basis, was similar to neutralizing antibodies that were specific for RBD. Aptamers demonstrated high specificity, binding with about 10-fold lower affinity to the related S1 domain from the original SARS virus, which also binds to ACE2. Overall, FANA aptamers show affinities comparable to previous DNA aptamers to RBD and S protein and directly block receptor interactions while using an alternative Xeno-nucleic acid (XNA) platform.
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Medina E, Yik EJ, Herdewijn P, Chaput JC. Functional Comparison of Laboratory-Evolved XNA Polymerases for Synthetic Biology. ACS Synth Biol 2021; 10:1429-1437. [PMID: 34029459 DOI: 10.1021/acssynbio.1c00048] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Artificial genetic polymers (XNAs) have enormous potential as new materials for synthetic biology, biotechnology, and molecular medicine; yet, very little is known about the biochemical properties of XNA polymerases that have been developed to synthesize and reverse-transcribe XNA polymers. Here, we compare the substrate specificity, thermal stability, reverse transcriptase activity, and fidelity of laboratory-evolved polymerases that were established to synthesize RNA, 2'-fluoroarabino nucleic acid (FANA), arabino nucleic acid (ANA), hexitol nucleic acid (HNA), threose nucleic acid (TNA), and phosphonomethylthreosyl nucleic acid (PMT). We find that the mutations acquired to facilitate XNA synthesis increase the tolerance of the enzymes for sugar-modified substrates with some sacrifice to protein-folding stability. Bst DNA polymerase was found to have weak reverse transcriptase activity on ANA and uncontrolled reverse transcriptase activity on HNA, differing from its known recognition of FANA and TNA templates. These data benchmark the activity of current XNA polymerases and provide opportunities for generating new polymerase variants that function with greater activity and substrate specificity.
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Affiliation(s)
| | | | - Piet Herdewijn
- KU Leuven, Rega Institute for Medical Research, Herestraat 49-bus 1041, 3000 Leuven, Belgium
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14
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El-Khoury R, Damha MJ. 2'-Fluoro-arabinonucleic Acid (FANA): A Versatile Tool for Probing Biomolecular Interactions. Acc Chem Res 2021; 54:2287-2297. [PMID: 33861067 DOI: 10.1021/acs.accounts.1c00125] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
This Account highlights the structural features that render 2'-deoxy-2'-fluoro-arabinonucleic acid (FANA) an ideal tool for mimicking DNA secondary structures and probing biomolecular interactions relevant to chemical biology.The high binding affinity of FANA to DNA and RNA has had implications in therapeutics. FANA can hybridize to complementary RNA, resulting in a predominant A-form helix stabilized by a network of 2'F-H8(purine) pseudohydrogen bonding interactions. We have shown that FANA/RNA hybrids are substrates of RNase H and Ago2, both implicated in the mechanism of action of antisense oligonucleotides (ASOs) and siRNA, respectvely. This knowledge has helped us study the conformational preferences of ASOs and siRNA as well as crRNA in CRISPR-associated Cas9, thereby revealing structural features crucial to biochemical activity.Additionally, FANA is of particular use in stabilizing noncanonical DNA structures. For instance, we have taken advantage of the anti N-glycosidic bond conformation of FANA monomers to induce a parallel topology in telomeric G-quadruplexes. Subsequent single-molecule FRET studies elucidated the mechanism by which these parallel G-quadruplexes are recognized and extended by telomerase. Similarly, we have utilized FANA to stabilize elusive telomeric i-motifs in the presence of concomitant parallel G-quadruplexes and under physiological conditions, thereby reinforcing their potential relevance to telomere biology. In another study, we adapted microarray technology and used FANA substitutions to enhance the binding affinity of the G-quadruplex thrombin-binding aptamer to its thrombin target.Finally, we discovered that DNA polymerases can synthesize FANA strands from DNA templates. On the basis of this property, other groups demonstrated that FANA, like DNA, can store hereditary information. They did so by engineering polymerases to efficiently transfer genetic information from DNA to FANA and retrieve it back into DNA. Subsequent studies showed that FANA could be evolved to acquire ribozyme-like endonuclease or ligase activity and to form high-affinity aptamers.Overall, the implications of these studies are remarkable because they promise a deeper understanding of human biochemistry for innovative therapeutic avenues. This Account summarizes past achievements and provides an outlook for inspiring the increased use of FANA in biological applications and fostering interdisciplinary collaborations.
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Affiliation(s)
- Roberto El-Khoury
- Department of Chemistry, McGill University, Montreal, Quebec H3A 0B8, Canada
| | - Masad J. Damha
- Department of Chemistry, McGill University, Montreal, Quebec H3A 0B8, Canada
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Yang C, Wu KB, Deng Y, Yuan J, Niu J. Geared Toward Applications: A Perspective on Functional Sequence-Controlled Polymers. ACS Macro Lett 2021; 10:243-257. [PMID: 34336395 PMCID: PMC8320758 DOI: 10.1021/acsmacrolett.0c00855] [Citation(s) in RCA: 42] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Sequence-controlled polymers are an emerging class of synthetic polymers with a regulated sequence of monomers. In the past decade, tremendous progress has been made in the synthesis of polymers with the sophisticated sequence control approaching the level manifested in biopolymers. In contrast, the exploration of novel functions that can be achieved by controlling synthetic polymer sequences represents an emerging focus in polymer science. This Viewpoint will survey recent advances in the functional applications of sequence-controlled polymers and provide a perspective on the challenges and outlook for pursuing future applications of this fascinating class of macromolecules.
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Affiliation(s)
- Cangjie Yang
- Department of Chemistry, Boston College, Chestnut Hill, Massachusetts 02467, United States
| | - Kevin B. Wu
- Department of Chemistry, Boston College, Chestnut Hill, Massachusetts 02467, United States
| | - Yu Deng
- Department of Chemistry, Boston College, Chestnut Hill, Massachusetts 02467, United States
| | - Jingsong Yuan
- Department of Chemistry, Boston College, Chestnut Hill, Massachusetts 02467, United States
| | - Jia Niu
- Department of Chemistry, Boston College, Chestnut Hill, Massachusetts 02467, United States
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16
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Gruenke PR, Alam KK, Singh K, Burke DH. 2'-fluoro-modified pyrimidines enhance affinity of RNA oligonucleotides to HIV-1 reverse transcriptase. RNA (NEW YORK, N.Y.) 2020; 26:1667-1679. [PMID: 32732393 PMCID: PMC7566575 DOI: 10.1261/rna.077008.120] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2020] [Accepted: 07/24/2020] [Indexed: 06/01/2023]
Abstract
Nucleic acid aptamers can be chemically modified to enhance function, but modifying previously selected aptamers can have nontrivial structural and functional consequences. We present a reselection strategy to evaluate the impact of several modifications on preexisting aptamer pools. RNA aptamer libraries with affinity to HIV-1 reverse transcriptase (RT) were retranscribed with 2'-F, 2'-OMe, or 2'-NH2 pyrimidines and subjected to three additional selection cycles. RT inhibition was observed for representative aptamers from several structural families identified by high-throughput sequencing when transcribed with their corresponding modifications. Thus, reselection identified specialized subsets of aptamers that tolerated chemical modifications from unmodified preenriched libraries. Inhibition was the strongest with the 2'-F-pyrimidine (2'-FY) RNAs, as compared to inhibition by the 2'-OMeY and 2'-NH2Y RNAs. Unexpectedly, a diverse panel of retroviral RTs were strongly inhibited by all 2'-FY-modified transcripts, including sequences that do not inhibit those RTs as unmodified RNA. The magnitude of promiscuous RT inhibition was proportional to mole fraction 2'-FY in the transcript. RT binding affinity by 2'-FY transcripts was more sensitive to salt concentration than binding by unmodified transcripts, indicating that interaction with retroviral RTs is more ionic in character for 2'-FY RNA than for unmodified 2'-OH RNA. These surprising features of 2'-FY-modified RNA may have general implications for applied aptamer technologies.
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Affiliation(s)
- Paige R Gruenke
- Department of Biochemistry, University of Missouri, Columbia, Missouri 65211, USA
- Bond Life Sciences Center, University of Missouri, Columbia, Missouri 65211, USA
| | - Khalid K Alam
- Department of Biochemistry, University of Missouri, Columbia, Missouri 65211, USA
- Bond Life Sciences Center, University of Missouri, Columbia, Missouri 65211, USA
| | - Kamal Singh
- Bond Life Sciences Center, University of Missouri, Columbia, Missouri 65211, USA
- Department of Veterinary Pathobiology, University of Missouri, Columbia, Missouri 65211, USA
| | - Donald H Burke
- Department of Biochemistry, University of Missouri, Columbia, Missouri 65211, USA
- Bond Life Sciences Center, University of Missouri, Columbia, Missouri 65211, USA
- Department of Molecular Microbiology and Immunology, University of Missouri, Columbia, Missouri 65211, USA
- Department of Biological Engineering, University of Missouri, Columbia, Missouri 65211, USA
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Nie P, Bai Y, Mei H. Synthetic Life with Alternative Nucleic Acids as Genetic Materials. Molecules 2020; 25:E3483. [PMID: 32751873 PMCID: PMC7435384 DOI: 10.3390/molecules25153483] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Revised: 07/29/2020] [Accepted: 07/29/2020] [Indexed: 12/20/2022] Open
Abstract
DNA, the fundamental genetic polymer of all living organisms on Earth, can be chemically modified to embrace novel functions that do not exist in nature. The key chemical and structural parameters for genetic information storage, heredity, and evolution have been elucidated, and many xenobiotic nucleic acids (XNAs) with non-canonical structures are developed as alternative genetic materials in vitro. However, it is still particularly challenging to replace DNAs with XNAs in living cells. This review outlines some recent studies in which the storage and propagation of genetic information are achieved in vivo by expanding genetic systems with XNAs.
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Affiliation(s)
| | | | - Hui Mei
- Shenzhen Key Laboratory of Synthetic Genomics, Guangdong Provincial Key Laboratory of Synthetic Genomics, CAS Key Laboratory of Quantitative Engineering Biology, Shenzhen Institute of Synthetic Biology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China; (P.N.); (Y.B.)
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Evolution of abiotic cubane chemistries in a nucleic acid aptamer allows selective recognition of a malaria biomarker. Proc Natl Acad Sci U S A 2020; 117:16790-16798. [PMID: 32631977 DOI: 10.1073/pnas.2003267117] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Nucleic acid aptamers selected through systematic evolution of ligands by exponential enrichment (SELEX) fold into exquisite globular structures in complex with protein targets with diverse translational applications. Varying the chemistry of nucleotides allows evolution of nonnatural nucleic acids, but the extent to which exotic chemistries can be integrated into a SELEX selection to evolve nonnatural macromolecular binding interfaces is unclear. Here, we report the identification of a cubane-modified aptamer (cubamer) against the malaria biomarker Plasmodium vivax lactate dehydrogenase (PvLDH). The crystal structure of the complex reveals an unprecedented binding mechanism involving a multicubane cluster within a hydrophobic pocket. The binding interaction is further stabilized through hydrogen bonding via cubyl hydrogens, previously unobserved in macromolecular binding interfaces. This binding mechanism allows discriminatory recognition of P. vivax over Plasmodium falciparum lactate dehydrogenase, thereby distinguishing these highly conserved malaria biomarkers for diagnostic applications. Together, our data demonstrate that SELEX can be used to evolve exotic nucleic acids bearing chemical functional groups which enable remarkable binding mechanisms which have never been observed in biology. Extending to other exotic chemistries will open a myriad of possibilities for functional nucleic acids.
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Chemical Modification of Aptamers for Increased Binding Affinity in Diagnostic Applications: Current Status and Future Prospects. Int J Mol Sci 2020; 21:ijms21124522. [PMID: 32630547 PMCID: PMC7350236 DOI: 10.3390/ijms21124522] [Citation(s) in RCA: 79] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Revised: 06/19/2020] [Accepted: 06/22/2020] [Indexed: 12/13/2022] Open
Abstract
Aptamers are short single stranded DNA or RNA oligonucleotides that can recognize analytes with extraordinary target selectivity and affinity. Despite their promising properties and diagnostic potential, the number of commercial applications remains scarce. In order to endow them with novel recognition motifs and enhanced properties, chemical modification of aptamers has been pursued. This review focuses on chemical modifications, aimed at increasing the binding affinity for the aptamer's target either in a non-covalent or covalent fashion, hereby improving their application potential in a diagnostic context. An overview of current methodologies will be given, thereby distinguishing between pre- and post-SELEX (Systematic Evolution of Ligands by Exponential Enrichment) modifications.
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Non-Invasive Delivery of Therapeutics into the Brain: The Potential of Aptamers for Targeted Delivery. Biomedicines 2020; 8:biomedicines8050120. [PMID: 32422973 PMCID: PMC7277349 DOI: 10.3390/biomedicines8050120] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Revised: 05/11/2020] [Accepted: 05/12/2020] [Indexed: 02/07/2023] Open
Abstract
The blood-brain barrier (BBB) is a highly specialised network of blood vessels that effectively separates the brain environment from the circulatory system. While there are benefits, in terms of keeping pathogens from entering the brain, the BBB also complicates treatments of brain pathologies by preventing efficient delivery of macromolecular drugs to diseased brain tissue. Although current non-invasive strategies of therapeutics delivery into the brain, such as focused ultrasound and nanoparticle-mediated delivery have shown various levels of successes, they still come with risks and limitations. This review discusses the current approaches of therapeutic delivery into the brain, with a specific focus on non-invasive methods. It also discusses the potential for aptamers as alternative delivery systems and several reported aptamers with promising preliminary results.
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