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Sethi S, Xu T, Sarkar A, Drees C, Jacob C, Walther A. Nuclease-Resistant L-DNA Tension Probes Enable Long-Term Force Mapping of Single Cells and Cell Consortia. Angew Chem Int Ed Engl 2024:e202413983. [PMID: 39212256 DOI: 10.1002/anie.202413983] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2024] [Revised: 08/26/2024] [Accepted: 08/29/2024] [Indexed: 09/04/2024]
Abstract
DNA-based tension probes with precisely programmable force responses provide important insights into cellular mechanosensing. However, their degradability in cell culture limits their use for long-term imaging, for instance, when cells migrate, divide, and differentiate. This is a critical limitation for providing insights into mechanobiology for these longer-term processes. Here, we present DNA-based tension probes that are entirely designed based on the stereoisomer of biological D-DNA, i.e., L-DNA. We demonstrate that L-DNA tension probes are essentially indestructible by nucleases and provide days-long imaging without significant loss in image quality. We also show their superiority already for short imaging times commonly used for classical D-DNA tension probes. We showcase the potential of these resilient probes to image minute movements, and for generating long term force maps of single cells and of collectively migrating cell populations.
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Affiliation(s)
- Soumya Sethi
- Life-like Materials and Systems, Department of Chemistry, University of Mainz, Duesbergweg 10-14, 55128, Mainz, Germany
| | - Tao Xu
- Life-like Materials and Systems, Department of Chemistry, University of Mainz, Duesbergweg 10-14, 55128, Mainz, Germany
| | - Aritra Sarkar
- Life-like Materials and Systems, Department of Chemistry, University of Mainz, Duesbergweg 10-14, 55128, Mainz, Germany
| | - Christoph Drees
- Life-like Materials and Systems, Department of Chemistry, University of Mainz, Duesbergweg 10-14, 55128, Mainz, Germany
| | - Claire Jacob
- Department of Biology, University of Mainz, Hanns-Dieter-Hüsch-Weg 15, 55128, Mainz, Germany
| | - Andreas Walther
- Life-like Materials and Systems, Department of Chemistry, University of Mainz, Duesbergweg 10-14, 55128, Mainz, Germany
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2
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Wang B, Kobeissy F, Golpich M, Cai G, Li X, Abedi R, Haskins W, Tan W, Benner SA, Wang KKW. Aptamer Technologies in Neuroscience, Neuro-Diagnostics and Neuro-Medicine Development. Molecules 2024; 29:1124. [PMID: 38474636 DOI: 10.3390/molecules29051124] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2024] [Revised: 02/15/2024] [Accepted: 02/27/2024] [Indexed: 03/14/2024] Open
Abstract
Aptamers developed using in vitro Systematic Evolution of Ligands by Exponential Enrichment (SELEX) technology are single-stranded nucleic acids 10-100 nucleotides in length. Their targets, often with specificity and high affinity, range from ions and small molecules to proteins and other biological molecules as well as larger systems, including cells, tissues, and animals. Aptamers often rival conventional antibodies with improved performance, due to aptamers' unique biophysical and biochemical properties, including small size, synthetic accessibility, facile modification, low production cost, and low immunogenicity. Therefore, there is sustained interest in engineering and adapting aptamers for many applications, including diagnostics and therapeutics. Recently, aptamers have shown promise as early diagnostic biomarkers and in precision medicine for neurodegenerative and neurological diseases. Here, we critically review neuro-targeting aptamers and their potential applications in neuroscience research, neuro-diagnostics, and neuro-medicine. We also discuss challenges that must be overcome, including delivery across the blood-brain barrier, increased affinity, and improved in vivo stability and in vivo pharmacokinetic properties.
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Affiliation(s)
- Bang Wang
- Department of Chemistry, University of Florida, Gainesville, FL 32611, USA
- The Foundation for Applied Molecular Evolution, 1501 NW 68th Terrace, Gainesville, FL 32605, USA
| | - Firas Kobeissy
- Center for Neurotrauma, MultiOmics and Biomarkers (CNMB), Department of Neurobiology, Neuroscience Institute, Morehouse School of Medicine, Atlanta, GA 30310, USA
- Department of Emergency Medicine, University of Florida, Gainesville, FL 32611, USA
- Brain Rehabilitation Research Center, Malcom Randall VA Medical Center, North Florida/South Georgia Veterans Health System, 1601 SW Archer Road, Gainesville, FL 32608, USA
- Center for Visual and Neurocognitive Rehabilitation (CVNR), Atlanta VA Health Care System, 1670 Clairmont Rd, Decatur, GA 30033, USA
| | - Mojtaba Golpich
- Center for Neurotrauma, MultiOmics and Biomarkers (CNMB), Department of Neurobiology, Neuroscience Institute, Morehouse School of Medicine, Atlanta, GA 30310, USA
| | - Guangzheng Cai
- Center for Neurotrauma, MultiOmics and Biomarkers (CNMB), Department of Neurobiology, Neuroscience Institute, Morehouse School of Medicine, Atlanta, GA 30310, USA
| | - Xiaowei Li
- Department of Chemistry, University of Florida, Gainesville, FL 32611, USA
| | - Reem Abedi
- Department of Biochemistry and Molecular Genetics, American University of Beirut, Beirut 1107-2020, Lebanon
| | - William Haskins
- Gryphon Bio, Inc., 611 Gateway Blvd. Suite 120 #253, South San Francisco, CA 94080, USA
| | - Weihong Tan
- Zhejiang Cancer Hospital, Hangzhou Institute of Medicine (HIM), The Chinese Academy of Sciences, Hangzhou 310022, China
| | - Steven A Benner
- The Foundation for Applied Molecular Evolution, 1501 NW 68th Terrace, Gainesville, FL 32605, USA
| | - Kevin K W Wang
- Center for Neurotrauma, MultiOmics and Biomarkers (CNMB), Department of Neurobiology, Neuroscience Institute, Morehouse School of Medicine, Atlanta, GA 30310, USA
- Department of Emergency Medicine, University of Florida, Gainesville, FL 32611, USA
- Brain Rehabilitation Research Center, Malcom Randall VA Medical Center, North Florida/South Georgia Veterans Health System, 1601 SW Archer Road, Gainesville, FL 32608, USA
- Center for Visual and Neurocognitive Rehabilitation (CVNR), Atlanta VA Health Care System, 1670 Clairmont Rd, Decatur, GA 30033, USA
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3
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Ji D, Feng H, Liew SW, Kwok CK. Modified nucleic acid aptamers: development, characterization, and biological applications. Trends Biotechnol 2023; 41:1360-1384. [PMID: 37302912 DOI: 10.1016/j.tibtech.2023.05.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2023] [Revised: 04/30/2023] [Accepted: 05/18/2023] [Indexed: 06/13/2023]
Abstract
Aptamers are single-stranded oligonucleotides that bind to their targets via specific structural interactions. To improve the properties and performance of aptamers, modified nucleotides are incorporated during or after a selection process such as systematic evolution of ligands by exponential enrichment (SELEX). We summarize the latest modified nucleotides and strategies used in modified (mod)-SELEX and post-SELEX to develop modified aptamers, highlight the methods used to characterize aptamer-target interactions, and present recent progress in modified aptamers that recognize different targets. We discuss the challenges and perspectives in further advancing the methodologies and toolsets to accelerate the discovery of modified aptamers, improve the throughput of aptamer-target characterization, and expand the functional diversity and complexity of modified aptamers.
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Affiliation(s)
- Danyang Ji
- Department of Chemistry and State Key Laboratory of Marine Pollution, City University of Hong Kong, Kowloon Tong, Hong Kong, SAR, China
| | - Hengxin Feng
- Department of Chemistry and State Key Laboratory of Marine Pollution, City University of Hong Kong, Kowloon Tong, Hong Kong, SAR, China
| | - Shiau Wei Liew
- Department of Chemistry and State Key Laboratory of Marine Pollution, City University of Hong Kong, Kowloon Tong, Hong Kong, SAR, China
| | - Chun Kit Kwok
- Department of Chemistry and State Key Laboratory of Marine Pollution, City University of Hong Kong, Kowloon Tong, Hong Kong, SAR, China; Shenzhen Research Institute of City University of Hong Kong, Shenzhen, China.
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4
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Qi S, Duan N, Khan IM, Dong X, Zhang Y, Wu S, Wang Z. Strategies to manipulate the performance of aptamers in SELEX, post-SELEX and microenvironment. Biotechnol Adv 2022; 55:107902. [DOI: 10.1016/j.biotechadv.2021.107902] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2021] [Revised: 12/21/2021] [Accepted: 12/30/2021] [Indexed: 02/07/2023]
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Recent Progress and Opportunities for Nucleic Acid Aptamers. Life (Basel) 2021; 11:life11030193. [PMID: 33671039 PMCID: PMC7997341 DOI: 10.3390/life11030193] [Citation(s) in RCA: 77] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Revised: 02/20/2021] [Accepted: 02/25/2021] [Indexed: 02/06/2023] Open
Abstract
Coined three decades ago, the term aptamer and directed evolution have now reached their maturity. The concept that nucleic acid could modulate the activity of target protein as ligand emerged from basic science studies of viruses. Aptamers are short nucleic acid sequences capable of specific, high-affinity molecular binding, which allow for therapeutic and diagnostic applications. Compared to traditional antibodies, aptamers have several advantages, including small size, flexible structure, good biocompatibility, and low immunogenicity. In vitro selection method is used to isolate aptamers that are specific for a desired target from a randomized oligonucleotide library. The first aptamer drug, Macugen, was approved by FDA in 2004, which was accompanied by many studies and clinical investigations on various targets and diseases. Despite much promise, most aptamers have failed to meet the requisite safety and efficacy standards in human clinical trials. Amid these setbacks, the emergence of novel technologies and recent advances in aptamer and systematic evolution of ligands by exponential enrichment (SELEX) design are fueling hope in this field. The unique properties of aptamer are gaining renewed interest in an era of COVID-19. The binding performance of an aptamer and reproducibility are still the key issues in tackling current hurdles in clinical translation. A thorough analysis of the aptamer binding under varying conditions and the conformational dynamics is warranted. Here, the challenges and opportunities of aptamers are reviewed with recent progress.
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6
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Liang Y, Yin W, Yin Y, Zhang W. Ghrelin Based Therapy of Metabolic Diseases. Curr Med Chem 2021; 28:2565-2576. [PMID: 32538716 PMCID: PMC11213490 DOI: 10.2174/0929867327666200615152804] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Revised: 05/04/2020] [Accepted: 05/18/2020] [Indexed: 11/22/2022]
Abstract
BACKGROUND Ghrelin, a unique 28 amino acid peptide hormone secreted by the gastric X/A like cells, is an endogenous ligand of the growth hormone secretagogue receptor (GHSR). Ghrelin-GHSR signaling has been found to exert various physiological functions, including stimulation of appetite, regulation of body weight, lipid and glucose metabolism, and increase of gut motility and secretion. This system is thus critical for energy homeostasis. OBJECTIVE The objective of this review is to highlight the strategies of ghrelin-GHSR based intervention for therapy of obesity and its related metabolic diseases. RESULTS Therapeutic strategies of metabolic disorders targeting the ghrelin-GHSR pathway involve neutralization of circulating ghrelin by antibodies and RNA spiegelmers, antagonism of ghrelin receptor by its antagonists and inverse agonists, inhibition of ghrelin O-acyltransferase (GOAT), as well as potential pharmacological approach to decrease ghrelin synthesis and secretion. CONCLUSION Various compounds targeting the ghrelin-GHSR system have shown promising efficacy for the intervention of obesity and relevant metabolic disorders in animals and in vitro. Further clinical trials to validate their efficacy in human beings are urgently needed.
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Affiliation(s)
- Yuan Liang
- Key Laboratory of Molecular Cardiovascular Science, Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing 100191, China
| | - Wenzhen Yin
- Key Laboratory of Molecular Cardiovascular Science, Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing 100191, China
| | - Yue Yin
- Key Laboratory of Molecular Cardiovascular Science, Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing 100191, China
| | - Weizhen Zhang
- Key Laboratory of Molecular Cardiovascular Science, Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing 100191, China
- Department of Surgery, University of Michigan Medical Center, Ann Arbor, MI 48109-0346, USA
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McKenzie LK, El-Khoury R, Thorpe JD, Damha MJ, Hollenstein M. Recent progress in non-native nucleic acid modifications. Chem Soc Rev 2021; 50:5126-5164. [DOI: 10.1039/d0cs01430c] [Citation(s) in RCA: 76] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
While Nature harnesses RNA and DNA to store, read and write genetic information, the inherent programmability, synthetic accessibility and wide functionality of these nucleic acids make them attractive tools for use in a vast array of applications.
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Affiliation(s)
- Luke K. McKenzie
- Institut Pasteur
- Department of Structural Biology and Chemistry
- Laboratory for Bioorganic Chemistry of Nucleic Acids
- CNRS UMR3523
- 75724 Paris Cedex 15
| | | | | | | | - Marcel Hollenstein
- Institut Pasteur
- Department of Structural Biology and Chemistry
- Laboratory for Bioorganic Chemistry of Nucleic Acids
- CNRS UMR3523
- 75724 Paris Cedex 15
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8
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Umar MI, Kwok CK. Specific suppression of D-RNA G-quadruplex-protein interaction with an L-RNA aptamer. Nucleic Acids Res 2020; 48:10125-10141. [PMID: 32976590 PMCID: PMC7544233 DOI: 10.1093/nar/gkaa759] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Revised: 08/28/2020] [Accepted: 09/04/2020] [Indexed: 02/06/2023] Open
Abstract
G-quadruplexes (G4s) are nucleic acid structure motifs that are of significance in chemistry and biology. The function of G4s is often governed by their interaction with G4-binding proteins. Few categories of G4-specific tools have been developed to inhibit G4-protein interactions; however, until now there is no aptamer tool being developed to do so. Herein, we present a novel L-RNA aptamer that can generally bind to D-RNA G-quadruplex (rG4) structure, and interfere with rG4-protein interaction. Using hTERC rG4 as the target for in vitro selection, we report the shortest L-aptamer being developed so far, with only 25 nucleotides. Notably, this new aptamer, L-Apt.4-1c, adopts a stem-loop structure with the loop folding into an rG4 motif with two G-quartet, demonstrates preferential binding toward rG4s over non-G4s and DNA G-quadruplexes (dG4s), and suppresses hTERC rG4-nucleolin interactions. We also show that inhibition of rG4-protein interaction using L-RNA aptamer L-Apt.4-1c is comparable to or better than G4-specific ligands such as carboxypyridostatin and QUMA-1 respectively, highlighting that our approach and findings expand the current G4 toolbox, and open a new avenue for diverse applications.
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Affiliation(s)
- Mubarak I Umar
- Department of Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong, Hong Kong SAR, China
| | - Chun Kit Kwok
- Department of Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong, Hong Kong SAR, China
- Shenzhen Research Institute of City University of Hong Kong, Shenzhen, China
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9
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Pegoraro S, Ros G, Sgubin M, Petrosino S, Zambelli A, Sgarra R, Manfioletti G. Targeting the intrinsically disordered architectural High Mobility Group A (HMGA) oncoproteins in breast cancer: learning from the past to design future strategies. Expert Opin Ther Targets 2020; 24:953-969. [PMID: 32970506 DOI: 10.1080/14728222.2020.1814738] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
INTRODUCTION Triple-negative breast cancer (TNBC) is the most difficult breast cancer subtype to treat because of its heterogeneity and lack of specific therapeutic targets. High Mobility Group A (HMGA) proteins are chromatin architectural factors that have multiple oncogenic functions in breast cancer, and they represent promising molecular therapeutic targets for this disease. AREAS COVERED We offer an overview of the strategies that have been exploited to counteract HMGA oncoprotein activities at the transcriptional and post-transcriptional levels. We also present the possibility of targeting cancer-associated factors that lie downstream of HMGA proteins and discuss the contribution of HMGA proteins to chemoresistance. EXPERT OPINION Different strategies have been exploited to counteract HMGA protein activities; these involve interfering with their nucleic acid binding properties and the blocking of HMGA expression. Some approaches have provided promising results. However, some unique characteristics of the HMGA proteins have not been exploited; these include their extensive protein-protein interaction network and their intrinsically disordered status that present the possibility that HMGA proteins could be involved in the formation of proteinaceous membrane-less organelles (PMLO) by liquid-liquid phase separation. These unexplored characteristics could open new pharmacological avenues to counteract the oncogenic contributions of HMGA proteins.
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Affiliation(s)
- Silvia Pegoraro
- Department of Life Sciences, University of Trieste , Trieste, Italy
| | - Gloria Ros
- Department of Life Sciences, University of Trieste , Trieste, Italy
| | - Michela Sgubin
- Department of Life Sciences, University of Trieste , Trieste, Italy
| | - Sara Petrosino
- Department of Life Sciences, University of Trieste , Trieste, Italy
| | | | - Riccardo Sgarra
- Department of Life Sciences, University of Trieste , Trieste, Italy
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10
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Tjhung KF, Sczepanski JT, Murtfeldt ER, Joyce GF. RNA-Catalyzed Cross-Chiral Polymerization of RNA. J Am Chem Soc 2020; 142:15331-15339. [PMID: 32805113 DOI: 10.1021/jacs.0c05635] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Biology relies almost exclusively on homochiral building blocks to drive the processes of life. Yet cross-chiral interactions can occur between macromolecules of the opposite handedness, including a previously described polymerase ribozyme that catalyzes the template-directed synthesis of enantio-RNA. The present study sought to optimize and generalize this activity, employing in vitro evolution to select cross-chiral polymerases that use either mono- or trinucleotide substrates that are activated as the 5'-triphosphate. There was only modest improvement of the former activity, but dramatic improvement of the latter, which enables the trinucleotide polymerase to react 102-103-fold faster than its ancestor and to accept substrates with all possible sequence combinations. The evolved ribozyme can assemble long RNAs from a mixture of trinucleotide building blocks, including a two-fragment form of the ancestral polymerase ribozyme. Further improvement of this activity could enable the generalized cross-chiral replication of RNA, which would establish a new paradigm for the chemical basis of Darwinian evolution.
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Affiliation(s)
- Katrina F Tjhung
- The Salk Institute, 10010 North Torrey Pines Road, La Jolla, California 92037, United States
| | - Jonathan T Sczepanski
- Department of Chemistry, Texas A&M University, P.O. Box 30012, College Station, Texas 77842, United States
| | - Eric R Murtfeldt
- The Salk Institute, 10010 North Torrey Pines Road, La Jolla, California 92037, United States
| | - Gerald F Joyce
- The Salk Institute, 10010 North Torrey Pines Road, La Jolla, California 92037, United States
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11
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Fu Z, Xiang J. Aptamers, the Nucleic Acid Antibodies, in Cancer Therapy. Int J Mol Sci 2020; 21:ijms21082793. [PMID: 32316469 PMCID: PMC7215806 DOI: 10.3390/ijms21082793] [Citation(s) in RCA: 81] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Revised: 04/09/2020] [Accepted: 04/15/2020] [Indexed: 02/06/2023] Open
Abstract
The arrival of the monoclonal antibody (mAb) technology in the 1970s brought with it the hope of conquering cancers to the medical community. However, mAbs, on the whole, did not achieve the expected wonder in cancer therapy although they do have demonstrated successfulness in the treatment of a few types of cancers. In 1990, another technology of making biomolecules capable of specific binding appeared. This technique, systematic evolution of ligands by exponential enrichment (SELEX), can make aptamers, single-stranded DNAs or RNAs that bind targets with high specificity and affinity. Aptamers have some advantages over mAbs in therapeutic uses particularly because they have little or no immunogenicity, which means the feasibility of repeated use and fewer side effects. In this review, the general properties of the aptamer, the advantages and limitations of aptamers, the principle and procedure of aptamer production with SELEX, particularly the undergoing studies in aptamers for cancer therapy, and selected anticancer aptamers that have entered clinical trials or are under active investigations are summarized.
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Affiliation(s)
- Zhaoying Fu
- Department of Biochemistry and Molecular Biology, College of Medicine, Yanan University, Yanan 716000, China
- Correspondence: (Z.F.); (J.X.)
| | - Jim Xiang
- Division of Oncology, University of Saskatchewan, Saskatoon, SA S7N 4H4, Canada
- Correspondence: (Z.F.); (J.X.)
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12
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Eiden LE, Goosens KA, Jacobson KA, Leggio L, Zhang L. Peptide-Liganded G Protein-Coupled Receptors as Neurotherapeutics. ACS Pharmacol Transl Sci 2020; 3:190-202. [PMID: 32296762 DOI: 10.1021/acsptsci.0c00017] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Indexed: 12/19/2022]
Abstract
Peptide-liganded G protein-coupled receptors (GPCRs) are a growing fraction of GPCR drug targets, concentrated in two of the five major GPCR structural classes. The basic physiology and pharmacology of some within the rhodopsin class, for example, the enkephalin (μ opioid receptor, MOR) and angiotensin (ATR) receptors, and most in class B, all the members of which are peptide receptors, are well-known, whereas others are less so. Furthermore, with the notable exception of opioid peptide receptors, the ability to translate from peptide to "drug-like" (i.e., low-molecular-weight nonpeptide) molecules, with desirable oral absorption, brain penetrance, and serum stability, has met with limited success. Yet, peripheral peptide administration in patients with metabolic disorders is clinically effective, suggesting that "drug-like" molecules for peptide receptor targets may not always be required for disease intervention. Here, we consider recent developments in GPCR structure analysis, intracellular signaling, and genetic analysis of peptide and peptide receptor knockout phenotypes in animal models. These lines of research converge on a better understanding of how peptides facilitate adaptive behaviors in mammals. They suggest pathways to translate this burgeoning information into identified drug targets for neurological and psychiatric illnesses such as obesity, addiction, anxiety disorders, and neurodegenerative diseases. Advances centered on the peptide ligands oxytocin, vasopressin, GLP-1, ghrelin, PACAP, NPY, and their GPCRs are considered here. These represent the spectrum of progress across the "virtual pipeline", of peptide receptors associated with many established drugs, those of long-standing interest for which clinical application is still under development, and those just coming into focus through basic research.
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Affiliation(s)
- Lee E Eiden
- Section on Molecular Neuroscience, National Institute of Mental Health, Bethesda, Maryland 20892, United States
| | - Ki Ann Goosens
- Icahn School of Medicine, Mt. Sinai Hospital, New York, New York 10029, United States
| | - Kenneth A Jacobson
- Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, Maryland 20892, United States
| | - Lorenzo Leggio
- Section on Clinical Psychoneuroendocrinology and Neuropsychopharmacology, National Institute on Alcohol Abuse and Alcoholism/National Institute on Drug Abuse, Bethesda, Maryland 20892, United States
| | - Limei Zhang
- Department of Physiology, Autonomous University of Mexico (UNAM), Mexico City 04510, Mexico
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13
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Schmidt C, Perbandt M, Klussmann S, Betzel C. Molecular characterization of a ghrelin-l-aptamer complex. J Mol Struct 2020. [DOI: 10.1016/j.molstruc.2019.127510] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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14
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Guan B, Zhang X. Aptamers as Versatile Ligands for Biomedical and Pharmaceutical Applications. Int J Nanomedicine 2020; 15:1059-1071. [PMID: 32110008 PMCID: PMC7035142 DOI: 10.2147/ijn.s237544] [Citation(s) in RCA: 66] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2019] [Accepted: 01/10/2020] [Indexed: 12/14/2022] Open
Abstract
Aptamers are a class of targeting ligands that bind exclusively to biomarkers of interest. Aptamers have been identified as candidates for the construction of various smart systems for therapy, diagnosis, bioimaging, and drug delivery due to their high target affinity and specificity. Aptamers are accounted as chemical antibodies that can be readily linked to drugs, sensors, signal enhancers, or nanocarriers for functionalization. Use of aptamer-guided medications, especially nanomedicines, has resulted in encouraging outcomes compared to those use of aptamer-free counterparts. This article reviews recent advances in the use of aptamers as targeting ligands for various biomedical and pharmaceutical purposes. Special interests focus on aptamer-based theranostics, biosensing, bioimaging, drug potentiation, and targeted drug delivery.
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Affiliation(s)
- Baozhang Guan
- Department of Nephrology, The First Affiliated Hospital of Jinan University, Guangzhou 510630, People's Republic of China
| | - Xingwang Zhang
- Department of Pharmaceutics, College of Pharmacy, Jinan University, Guangzhou 510632, People's Republic of China
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15
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Chan C, Kwok CK. Specific Binding of a
d
‐RNA G‐Quadruplex Structure with an
l
‐RNA Aptamer. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.201914955] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Affiliation(s)
- Chun‐Yin Chan
- Department of ChemistryCity University of Hong Kong Tat Chee Avenue Kowloon Tong, Hong Kong SAR China
| | - Chun Kit Kwok
- Department of ChemistryCity University of Hong Kong Tat Chee Avenue Kowloon Tong, Hong Kong SAR China
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16
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Chan CY, Kwok CK. Specific Binding of a d-RNA G-Quadruplex Structure with an l-RNA Aptamer. Angew Chem Int Ed Engl 2020; 59:5293-5297. [PMID: 31975549 DOI: 10.1002/anie.201914955] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2019] [Revised: 01/06/2020] [Indexed: 01/24/2023]
Abstract
G-quadruplex (G4) structures are of general importance in chemistry and biology, such as in biosensing, gene regulation, and cancers. Although a large repertoire of G4-binding tools has been developed, no aptamer has been developed to interact with G4. Moreover, the G4 selectivity of current toolkits is very limited. Herein, we report the first l-RNA aptamer that targets a d-RNA G-quadruplex (rG4). Using TERRA rG4 as an example, our results reveal that this l-RNA aptamer, Ap3-7, folds into a unique secondary structure, exhibits high G4 selectivity and effectively interferes with TERRA-rG4-RHAU53 binding. Our approach and findings open a new door in further developing G4-specific tools for diverse applications.
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Affiliation(s)
- Chun-Yin Chan
- Department of Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong, Hong Kong SAR, China
| | - Chun Kit Kwok
- Department of Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong, Hong Kong SAR, China
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17
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Citro A, Pellegrini S, Dugnani E, Eulberg D, Klussmann S, Piemonti L. CCL2/MCP-1 and CXCL12/SDF-1 blockade by L-aptamers improve pancreatic islet engraftment and survival in mouse. Am J Transplant 2019; 19:3131-3138. [PMID: 31267721 DOI: 10.1111/ajt.15518] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Revised: 06/06/2019] [Accepted: 06/24/2019] [Indexed: 01/25/2023]
Abstract
The blockade of pro-inflammatory mediators is a successful approach to improve the engraftment after islet transplantation. L-aptamers are chemically synthesized, nonimmunogenic bio-stable oligonucleotides that bind and inhibit target molecules conceptually similar to antibodies. We aimed to evaluate if blockade-aptamer-based inhibitors of C-C Motif Chemokine Ligand 2/monocyte chemoattractant protein-1 (CCL2/MCP-1) and C-X-C Motif Chemokine Ligand 12/stromal cell-derived factor-1 (CXCL12/SDF-1) are able to favor islet survival in mouse models for islet transplantation and for type 1 diabetes. We evaluated the efficacy of the CCL2-specific mNOX-E36 and the CXCL12-specific NOX-A12 on islet survival in a syngeneic mouse model of intraportal islet transplantation and in a multiple low doses of streptozotocin (MLD-STZ) diabetes induction model. Moreover, we characterized intrahepatic infiltrated leukocytes by flow cytometry before and 3 days after islet infusion in presence or absence of these inhibitors. The administration for 14 days of mNOX-E36 and NOX-A12 significantly improved islet engraftment, either compound alone or in combination. Intrahepatic islet transplantation recruited CD45+ leucocytes and more specifically CD45+/CD11b+ mono/macrophages; mNOX-E36 and NOX-A12 treatments significantly decreased the recruitment of inflammatory monocytes, CD11b+ /Ly6Chigh /CCR2+ and CD11b+ /Ly6Chigh /CXCR4+ cells, respectively. Additionally, both L-aptamers significantly attenuated diabetes progression in the MLD-STZ model. In conclusion, CCL2/MCP-1 and CXCL12/SDF-1 blockade by L-aptamers is an efficient strategy to improve islet engraftment and survival.
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Affiliation(s)
- Antonio Citro
- San Raffaele Diabetes Research Institute, IRCCS Ospedale San Raffaele, Milan, Italy
| | - Silvia Pellegrini
- San Raffaele Diabetes Research Institute, IRCCS Ospedale San Raffaele, Milan, Italy
| | - Erica Dugnani
- San Raffaele Diabetes Research Institute, IRCCS Ospedale San Raffaele, Milan, Italy
| | | | - Sven Klussmann
- NOXXON Pharma AG, Berlin, Germany.,Aptarion Biotech AG, Berlin, Germany
| | - Lorenzo Piemonti
- San Raffaele Diabetes Research Institute, IRCCS Ospedale San Raffaele, Milan, Italy.,Vita-Salute San Raffaele University, Milan, Italy
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18
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Wakui K, Abe A, Yoshitomi T, Furusho H, Yoshimoto K. High Enrichment of Nucleobase-modified Aptamers in Early Selection Rounds by Microbeads-assisted Capillary Electrophoresis SELEX. ANAL SCI 2019; 35:585-588. [PMID: 31080213 DOI: 10.2116/analsci.18sdn04] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Nucleobase-modified aptamers are attractive candidates for diagnostic and therapeutic agents due to the high affinity, stability and functionality. However, since even conventional SELEX requires many selection rounds, acquisition of modified aptamers is much more laborious. Herein, microbeads-assisted capillary electrophoresis (MACE)-SELEX was applied against thrombin using the indole-modified DNA library. After only three selection rounds, we successfully enriched the modified aptamers and they showed slower off-rate than reported aptamers, suggesting MACE-SELEX is a promising approach for rapid identification of modified aptamers.
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Affiliation(s)
- Koji Wakui
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo
| | - Akihito Abe
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo
| | - Toru Yoshitomi
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo
| | - Hitoshi Furusho
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo.,Chemical General Division, Nissan Chemical Industries, Ltd
| | - Keitaro Yoshimoto
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo.,JST, PRESTO, The University of Tokyo
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19
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Abstract
PURPOSE OF REVIEW Obesity is affecting over 600 million adults worldwide and has numerous negative effects on health. Since ghrelin positively regulates food intake and body weight, targeting its signaling to induce weight loss under conditions of obesity seems promising. Thus, the present work reviews and discusses different possibilities to alter ghrelin signaling. RECENT FINDINGS Ghrelin signaling can be altered by RNA Spiegelmers, GHSR/Fc, ghrelin-O-acyltransferase inhibitors as well as antagonists, and inverse agonists of the ghrelin receptor. PF-05190457 is the first inverse agonist of the ghrelin receptor tested in humans shown to inhibit growth hormone secretion, gastric emptying, and reduce postprandial glucose levels. Effects on body weight were not examined. Although various highly promising agents targeting ghrelin signaling exist, so far, they were mostly only tested in vitro or in animal models. Further research in humans is thus needed to further assess the effects of ghrelin antagonism on body weight especially under conditions of obesity.
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Affiliation(s)
- Martha A Schalla
- Charité Center for Internal Medicine and Dermatology, Charité Center for Internal Medicine and Dermatology, Department for Psychosomatic Medicine; Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Andreas Stengel
- Charité Center for Internal Medicine and Dermatology, Charité Center for Internal Medicine and Dermatology, Department for Psychosomatic Medicine; Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany.
- Department of Psychosomatic Medicine and Psychotherapy, Medical University Hospital Tübingen, Tübingen, Germany.
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20
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Mustafá ER, Cordisco Gonzalez S, Raingo J. Ghrelin Selectively Inhibits CaV3.3 Subtype of Low-Voltage-Gated Calcium Channels. Mol Neurobiol 2019; 57:722-735. [DOI: 10.1007/s12035-019-01738-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Accepted: 08/16/2019] [Indexed: 01/01/2023]
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21
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Young BE, Kundu N, Sczepanski JT. Mirror-Image Oligonucleotides: History and Emerging Applications. Chemistry 2019; 25:7981-7990. [PMID: 30913332 PMCID: PMC6615976 DOI: 10.1002/chem.201900149] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2019] [Indexed: 01/13/2023]
Abstract
As chiral molecules, naturally occurring d-oligonucleotides have enantiomers, l-DNA and l-RNA, which are comprised of l-(deoxy)ribose sugars. These mirror-image oligonucleotides have the same physical and chemical properties as that of their native d-counterparts, yet are highly orthogonal to the stereospecific environment of biology. Consequently, l-oligonucleotides are resistant to nuclease degradation and many of the off-target interactions that plague traditional d-oligonucleotide-based technologies; thus making them ideal for biomedical applications. Despite a flurry of interest during the early 1990s, the inability of d- and l-oligonucleotides to form contiguous Watson-Crick base pairs with each other has ultimately led to the perception that l-oligonucleotides have only limited utility. Recently, however, scientists have begun to uncover novel strategies to harness the bio-orthogonality of l-oligonucleotides, while overcoming (and even exploiting) their inability to Watson-Crick base pair with the natural polymer. Herein, a brief history of l-oligonucleotide research is presented and emerging l-oligonucleotide-based technologies, as well as their applications in research and therapy, are presented.
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Affiliation(s)
- Brian E. Young
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States
| | - Nandini Kundu
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States
| | - Jonathan T. Sczepanski
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States
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22
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Al-Massadi O, Müller T, Tschöp M, Diéguez C, Nogueiras R. Ghrelin and LEAP-2: Rivals in Energy Metabolism. Trends Pharmacol Sci 2018; 39:685-694. [DOI: 10.1016/j.tips.2018.06.004] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Revised: 06/04/2018] [Accepted: 06/04/2018] [Indexed: 01/13/2023]
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23
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Avci-Adali M. Selection and Application of Aptamers and Intramers. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 917:241-58. [PMID: 27236559 DOI: 10.1007/978-3-319-32805-8_11] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Aptamers are auspicious nucleic acid ligands for targeting different molecules, such as small molecules, peptides, proteins, or even whole living cells. They are short single-stranded DNA or RNA oligonucleotides, which can fold into complex three-dimensional structures and bind selectively their targets. Using the combinatorial chemistry process SELEX (Systematic Evolution of Ligands by EXponential Enrichment), target specific aptamers can be selected. These aptamers have a variety of application possibilities and can be used as sensors, diagnostic, imaging or therapeutic agents, and in the field of regenerative medicine for tissue engineering.
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Affiliation(s)
- Meltem Avci-Adali
- Department of Thoracic and Cardiovascular Surgery, University Hospital Tuebingen, Calwerstr. 7/1, 72076, Tuebingen, Germany.
- RiNA GmbH, Berlin, Germany.
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24
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QIN SY, CHEN ND, WANG Q, HUANG J, HE XX, LIU JB, GUO QP, YANG XH, WANG KM. Application of Nucleic Acid Aptamers in Polypeptides Researches. CHINESE JOURNAL OF ANALYTICAL CHEMISTRY 2017. [DOI: 10.1016/s1872-2040(17)61055-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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25
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Dudek M, Trylska J. Molecular Dynamics Simulations of l-RNA Involving Homo- and Heterochiral Complexes. J Chem Theory Comput 2017; 13:1244-1253. [DOI: 10.1021/acs.jctc.6b01075] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Affiliation(s)
- Marta Dudek
- Centre
of New Technologies, University of Warsaw, Banacha 2c, 02-097 Warsaw, Poland
- Institute
of Biochemistry and Biophysics, Polish Academy of Sciences, Pawińskiego
5a, 02-106 Warsaw, Poland
- Department
of Hematology, Oncology and Internal Diseases, Medical University of Warsaw, Al. Żwirki i Wigury 61, 02-091 Warsaw, Poland
| | - Joanna Trylska
- Centre
of New Technologies, University of Warsaw, Banacha 2c, 02-097 Warsaw, Poland
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26
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Lipi F, Chen S, Chakravarthy M, Rakesh S, Veedu RN. In vitro evolution of chemically-modified nucleic acid aptamers: Pros and cons, and comprehensive selection strategies. RNA Biol 2016; 13:1232-1245. [PMID: 27715478 PMCID: PMC5207382 DOI: 10.1080/15476286.2016.1236173] [Citation(s) in RCA: 81] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Nucleic acid aptamers are single-stranded DNA or RNA oligonucleotide sequences that bind to a specific target molecule with high affinity and specificity through their ability to adopt 3-dimensional structure in solution. Aptamers have huge potential as targeted therapeutics, diagnostics, delivery agents and as biosensors. However, aptamers composed of natural nucleotide monomers are quickly degraded in vivo and show poor pharmacodynamic properties. To overcome this, chemically-modified nucleic acid aptamers are developed by incorporating modified nucleotides after or during the selection process by Systematic Evolution of Ligands by EXponential enrichment (SELEX). This review will discuss the development of chemically-modified aptamers and provide the pros and cons, and new insights on in vitro aptamer selection strategies by using chemically-modified nucleic acid libraries.
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Affiliation(s)
- Farhana Lipi
- a Western Australian Neuroscience Research Institute , Perth , Australia
| | - Suxiang Chen
- a Western Australian Neuroscience Research Institute , Perth , Australia.,b Centre for Comparative Genomics, Murdoch University , Perth , Australia
| | - Madhuri Chakravarthy
- a Western Australian Neuroscience Research Institute , Perth , Australia.,b Centre for Comparative Genomics, Murdoch University , Perth , Australia
| | - Shilpa Rakesh
- a Western Australian Neuroscience Research Institute , Perth , Australia
| | - Rakesh N Veedu
- a Western Australian Neuroscience Research Institute , Perth , Australia.,b Centre for Comparative Genomics, Murdoch University , Perth , Australia
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27
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Liu A, Huang C, Xu J, Cai X. Lentivirus-mediated shRNA interference of ghrelin receptor blocks proliferation in the colorectal cancer cells. Cancer Med 2016; 5:2417-26. [PMID: 27464938 PMCID: PMC5055151 DOI: 10.1002/cam4.723] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2015] [Revised: 03/01/2016] [Accepted: 03/07/2016] [Indexed: 12/12/2022] Open
Abstract
Ghrelin, an orexigenic peptide, acts via the growth hormone secretagogue receptor (GHSR) to stimulate the release of growth hormone. Moreover, it has a range of biological actions, including the stimulation of food intake, modulation of insulin signaling and cardiovascular effects. Recently, it has been demonstrated that ghrelin has a proliferative and antiapoptotic effects in cancers, suggesting a potential role in promoting tumor growth. However, it remains unknown whether GHSR contributes to colorectal cancer proliferation. In this study, the therapeutic effect of lentivirus‐mediated short hairpin RNA (shRNA) targeting ghrelin receptor 1a (GHSR1a) was analyzed in colorectal cancer cell line SW480 both in vitro and in vivo. Our study demonstrated that ghrelin and GHSR1a are significantly upregulated in cancerous colorectal tissue samples and cell lines. In vitro, human colorectal cancer cell line SW480 with downregulation of GHSR1a by shRNA showed significant inhibition of cell viability compared with blank control (BC) or scrambled control (SC) regardless of the application of exogenous ghrelin. Furthermore, GHSR1a silencing by target specific shRNA was shown capable of increasing PTEN, inhibiting AKT phosphorylation and promoting the release of p53 in SW480 cells. In addition, the effects of GHSR1a knockdown were further explored in vivo using colorectal tumor xenograft mouse model. The tumor weights were decreased markedly in GHSR1α knockdown SW480 mouse xenograft tumors compared with blank control or negative control tumors. Our results suggested that the expression of GHSR1a is significantly correlated with the growth of colorectal cancer cells, and the GHSR1a knockdown approach may be a potential therapy for the treatment of colorectal cancer.
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Affiliation(s)
- An Liu
- Department of General Surgery, The First People Hospital of Yueyang, 39 Dong mao ling Road, Yueyang, Hunan, 325000, China.
| | - Chenggang Huang
- Department of General Surgery, The First People Hospital of Yueyang, 39 Dong mao ling Road, Yueyang, Hunan, 325000, China
| | - Jia Xu
- Department of General Surgery, The First People Hospital of Yueyang, 39 Dong mao ling Road, Yueyang, Hunan, 325000, China
| | - Xuehong Cai
- Department of General Surgery, The First People Hospital of Yueyang, 39 Dong mao ling Road, Yueyang, Hunan, 325000, China
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28
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Abstract
Aptamers are single strand DNA or RNA molecules, selected by an iterative process known as Systematic Evolution of Ligands by Exponential Enrichment (SELEX). Due to various advantages of aptamers such as high temperature stability, animal free, cost effective production and its high affinity and selectivity for its target make them attractive alternatives to monoclonal antibody for use in diagnostic and therapeutic purposes. Aptamer has been generated against vesicular endothelial growth factor 165 involved in age related macular degeneracy. Macugen was the first FDA approved aptamer based drug that was commercialized. Later other aptamers were also developed against blood clotting proteins, cancer proteins, antibody E, agents involved in diabetes nephropathy, autoantibodies involved in autoimmune disorders, etc. Aptamers have also been developed against viruses and could work with other antiviral agents in treating infections.
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Affiliation(s)
- Abhishek Parashar
- Research Scholar, Animal Biochemistry Division, National Dairy Research Institute , Karnal, India
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29
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Crivianu-Gaita V, Thompson M. Aptamers, antibody scFv, and antibody Fab' fragments: An overview and comparison of three of the most versatile biosensor biorecognition elements. Biosens Bioelectron 2016; 85:32-45. [PMID: 27155114 DOI: 10.1016/j.bios.2016.04.091] [Citation(s) in RCA: 177] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Revised: 04/11/2016] [Accepted: 04/26/2016] [Indexed: 01/14/2023]
Abstract
The choice of biosensing elements is crucial for the development of the optimal biosensor. Three of the most versatile biosensing elements are antibody single-chain Fv fragments (scFv), antibody fragment-antigen binding (Fab') units, and aptamers. This article provides an overview of these three biorecognition elements with respects to their synthesis/engineering, various immobilization techniques, and examples of their use in biosensors. Furthermore, the final section of the review compares and contrasts their characteristics (time/cost of development, ease and variability of immobilization, affinity, stability) illustrating their advantages and disadvantages. Overall, scFv fragments are found to display the highest customizability (i.e. addition of functional groups, immobilizing peptides, etc.) due to recombinant synthesis techniques. If time and cost are an issue in the development of the biosensor, Fab' fragments should be chosen as they are relatively cheap and can be developed quickly from whole antibodies (several days). However, if there are sufficient funds and time is not a factor, aptamers should be utilized as they display the greatest affinity towards their target analytes and are extremely stable (excellent biosensor regenerability).
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Affiliation(s)
| | - Michael Thompson
- Department of Chemistry, University of Toronto, Toronto, ON, M5S 3H6, Canada.
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30
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Chumakov AM, Yuhina ES, Frolova EI, Kravchenko JE, Chumakov SP. Expanding the application potential of DNA aptamers by their functionalization. RUSSIAN JOURNAL OF BIOORGANIC CHEMISTRY 2016. [DOI: 10.1134/s1068162016010027] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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31
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Ma H, Liu J, Ali MM, Mahmood MAI, Labanieh L, Lu M, Iqbal SM, Zhang Q, Zhao W, Wan Y. Nucleic acid aptamers in cancer research, diagnosis and therapy. Chem Soc Rev 2015; 44:1240-56. [PMID: 25561050 DOI: 10.1039/c4cs00357h] [Citation(s) in RCA: 167] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Aptamers are single-stranded DNA or RNA oligomers, identified from a random sequence pool, with the ability to form unique and versatile tertiary structures that bind to cognate molecules with superior specificity. Their small size, excellent chemical stability and low immunogenicity enable them to rival antibodies in cancer imaging and therapy applications. Their facile chemical synthesis, versatility in structural design and engineering, and the ability for site-specific modifications with functional moieties make aptamers excellent recognition motifs for cancer biomarker discovery and detection. Moreover, aptamers can be selected or engineered to regulate cancer protein functions, as well as to guide anti-cancer drug design or screening. This review summarizes their applications in cancer, including cancer biomarker discovery and detection, cancer imaging, cancer therapy, and anti-cancer drug discovery. Although relevant applications are relatively new, the significant progress achieved has demonstrated that aptamers can be promising players in cancer research.
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Affiliation(s)
- Haitao Ma
- The Department of Cardiothoracic Surgery, The First Affiliated Hospital of Soochow University, Soochow University, Suzhou, Jiangsu 215006, China
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32
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Steculorum SM, Collden G, Coupe B, Croizier S, Lockie S, Andrews ZB, Jarosch F, Klussmann S, Bouret SG. Neonatal ghrelin programs development of hypothalamic feeding circuits. J Clin Invest 2015; 125:846-58. [PMID: 25607843 DOI: 10.1172/jci73688] [Citation(s) in RCA: 113] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2013] [Accepted: 11/06/2014] [Indexed: 01/24/2023] Open
Abstract
A complex neural network regulates body weight and energy balance, and dysfunction in the communication between the gut and this neural network is associated with metabolic diseases, such as obesity. The stomach-derived hormone ghrelin stimulates appetite through interactions with neurons in the arcuate nucleus of the hypothalamus (ARH). Here, we evaluated the physiological and neurobiological contribution of ghrelin during development by specifically blocking ghrelin action during early postnatal development in mice. Ghrelin blockade in neonatal mice resulted in enhanced ARH neural projections and long-term metabolic effects, including increased body weight, visceral fat, and blood glucose levels and decreased leptin sensitivity. In addition, chronic administration of ghrelin during postnatal life impaired the normal development of ARH projections and caused metabolic dysfunction. Consistent with these observations, direct exposure of postnatal ARH neuronal explants to ghrelin blunted axonal growth and blocked the neurotrophic effect of the adipocyte-derived hormone leptin. Moreover, chronic ghrelin exposure in neonatal mice also attenuated leptin-induced STAT3 signaling in ARH neurons. Collectively, these data reveal that ghrelin plays an inhibitory role in the development of hypothalamic neural circuits and suggest that proper expression of ghrelin during neonatal life is pivotal for lifelong metabolic regulation.
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33
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Wellman MK, Patterson ZR, MacKay H, Darling JE, Mani BK, Zigman JM, Hougland JL, Abizaid A. Novel Regulator of Acylated Ghrelin, CF801, Reduces Weight Gain, Rebound Feeding after a Fast, and Adiposity in Mice. Front Endocrinol (Lausanne) 2015; 6:144. [PMID: 26441834 PMCID: PMC4585333 DOI: 10.3389/fendo.2015.00144] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/19/2015] [Accepted: 09/01/2015] [Indexed: 01/04/2023] Open
Abstract
Ghrelin is a 28 amino acid hormonal peptide that is intimately related to the regulation of food intake and body weight. Once secreted, ghrelin binds to the growth hormone secretagogue receptor-1a, the only known receptor for ghrelin and is capable of activating a number of signaling cascades, ultimately resulting in an increase in food intake and adiposity. Because ghrelin has been linked to overeating and the development of obesity, a number of pharmacological interventions have been generated in order to interfere with either the activation of ghrelin or interrupting ghrelin signaling as a means to reducing appetite and decrease weight gain. Here, we present a novel peptide, CF801, capable of reducing circulating acylated ghrelin levels and subsequent body weight gain and adiposity. To this end, we show that IP administration of CF801 is sufficient to reduce circulating plasma acylated ghrelin levels. Acutely, intraperitoneal injections of CF801 resulted in decreased rebound feeding after an overnight fast. When delivered chronically, they decreased weight gain and adiposity without affecting caloric intake. CF801, however, did cause a change in diet preference, decreasing preference for a high-fat diet and increasing preference for regular chow diet. Given the complexity of ghrelin receptor function, we propose that CF801, along with other compounds that regulate ghrelin secretion, may prove to be a beneficial tool in the study of the ghrelin system, and potential targets for ghrelin-based obesity treatments without altering the function of ghrelin receptors.
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Affiliation(s)
| | | | - Harry MacKay
- Department of Neuroscience, Carleton University, Ottawa, ON, Canada
| | | | - Bharath K. Mani
- Department of Internal Medicine, Division of Hypothalamic Research, The University of Texas Southwestern Medical Center, Dallas, TX, USA
- Department of Internal Medicine, Division of Endocrinology and Metabolism, The University of Texas Southwestern Medical Center, Dallas, TX, USA
- Department of Psychiatry, The University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Jeffrey M. Zigman
- Department of Internal Medicine, Division of Hypothalamic Research, The University of Texas Southwestern Medical Center, Dallas, TX, USA
- Department of Internal Medicine, Division of Endocrinology and Metabolism, The University of Texas Southwestern Medical Center, Dallas, TX, USA
- Department of Psychiatry, The University of Texas Southwestern Medical Center, Dallas, TX, USA
| | | | - Alfonso Abizaid
- Department of Neuroscience, Carleton University, Ottawa, ON, Canada
- *Correspondence: Alfonso Abizaid, Department of Neuroscience, Carleton University, 1125 Colonel By Drive, 329 Life Science Research Building, Ottawa, ON K1S 5B6, Canada,
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34
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Vater A, Klussmann S. Turning mirror-image oligonucleotides into drugs: the evolution of Spiegelmer(®) therapeutics. Drug Discov Today 2014; 20:147-55. [PMID: 25236655 DOI: 10.1016/j.drudis.2014.09.004] [Citation(s) in RCA: 173] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2014] [Revised: 08/11/2014] [Accepted: 09/08/2014] [Indexed: 12/22/2022]
Abstract
Spiegelmers are synthetic target-binding oligonucleotides built from non-natural l-nucleotides. Like aptamers, Spiegelmers fold into distinct shapes that bind the targets with high affinity and selectivity. Furthermore, the mirror-image configuration confers plasma stability and immunological passivity. Various Spiegelmers against pharmacologically attractive targets were shown to be efficacious in animal models. Three Spiegelmer candidates: emapticap pegol (NOX-E36; anti-CCL2), olaptesed pegol (NOX-A12; anti-CXCL12) and lexaptepid pegol (NOX-H94; anti-hepcidin), underwent regulatory safety studies, demonstrated good safety profiles in healthy volunteers and were taken into Phase IIa studies in patients. Proof-of-concept for emapticap pegol has recently been demonstrated in diabetic nephropathy patients. Furthermore, promising interim Phase IIa data of olaptesed pegol and lexapteptid pegol also suggest efficacy in the respective patient populations.
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Affiliation(s)
- Axel Vater
- NOXXON Pharma AG, Max-Dohrn-Strasse 8-10, 10589 Berlin, Germany.
| | - Sven Klussmann
- NOXXON Pharma AG, Max-Dohrn-Strasse 8-10, 10589 Berlin, Germany
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35
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Physiological roles of ghrelin on obesity. Obes Res Clin Pract 2014; 8:e405-13. [DOI: 10.1016/j.orcp.2013.10.002] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/04/2013] [Revised: 08/28/2013] [Accepted: 10/08/2013] [Indexed: 02/06/2023]
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36
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New Technologies Provide Quantum Changes in the Scale, Speed, and Success of SELEX Methods and Aptamer Characterization. MOLECULAR THERAPY. NUCLEIC ACIDS 2014; 3:e183. [PMID: 25093707 PMCID: PMC4221594 DOI: 10.1038/mtna.2014.34] [Citation(s) in RCA: 126] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/21/2014] [Accepted: 06/10/2014] [Indexed: 12/24/2022]
Abstract
Single-stranded oligonucleotide aptamers have attracted great attention in the past decade because of their diagnostic and therapeutic potential. These versatile, high affinity and specificity reagents are selected by an iterative in vitro process called SELEX, Systematic Evolution of Ligands by Exponential Enrichment. Numerous SELEX methods have been developed for aptamer selections; some that are simple and straightforward, and some that are specialized and complicated. The method of SELEX is crucial for selection of an aptamer with desired properties; however, success also depends on the starting aptamer library, the target molecule, aptamer enrichment monitoring assays, and finally, the analysis and characterization of selected aptamers. Here, we summarize key recent developments in aptamer selection methods, as well as other aspects of aptamer selection that have significant impact on the outcome. We discuss potential pitfalls and limitations in the selection process with an eye to aid researchers in the choice of a proper SELEX strategy, and we highlight areas where further developments and improvements are desired. We believe carefully designed multiplexed selection methods, when complemented with high-throughput downstream analysis and characterization assays, will yield numerous high-affinity aptamers to protein and small molecule targets, and thereby generate a vast array of reagents for probing basic biological mechanisms and implementing new diagnostic and therapeutic applications in the near future.
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Chlorin e6 Conjugated Interleukin-6 Receptor Aptamers Selectively Kill Target Cells Upon Irradiation. MOLECULAR THERAPY. NUCLEIC ACIDS 2014; 3:e143. [PMID: 24481022 PMCID: PMC3910004 DOI: 10.1038/mtna.2013.70] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/10/2013] [Accepted: 11/11/2013] [Indexed: 02/01/2023]
Abstract
Photodynamic therapy (PDT) uses the therapeutic properties of light in combination with certain chemicals, called photosensitizers, to successfully treat brain, breast, prostate, and skin cancers. To improve PDT, current research focuses on the development of photosensitizers to specifically target cancer cells. In the past few years, aptamers have been developed to directly deliver cargo molecules into target cells. We conjugated the photosensitizer chlorin e6 (ce6) with a human interleukin-6 receptor (IL-6R) binding RNA aptamer, AIR-3A yielding AIR-3A-ce6 for application in high efficient PDT. AIR-3A-ce6 was rapidly and specifically internalized by IL-6R presenting (IL-6R(+)) cells. Upon light irradiation, targeted cells were selectively killed, while free ce6 did not show any toxic effect. Cells lacking the IL-6R were also not affected by AIR-3A-ce6. With this approach, we improved the target specificity of ce6-mediated PDT. In the future, other tumor-specific aptamers might be used to selectively localize photosensitizers into cells of interest and improve the efficacy and specificity of PDT in cancer and other diseases.Molecular Therapy-Nucleic Acids (2014) 3, e143; doi:10.1038/mtna.2013.70; published online 21 January 2014.
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Abstract
BACKGROUND Recent advances in physiological understanding of obesity have provided a new perspective on its origins and potential treatments. SOURCES OF DATA This review is based on published literature in the fields of gut hormone physiology and the neuroendocrinology of obesity. AREAS OF AGREEMENT The gut releases several hormones in response to changes in nutritional status. Changes in plasma concentration of these hormones are responded to by central nervous system circuits controlling appetite and energy expenditure. Modified gut hormone secretion is responsible, at least in part, for weight loss after certain forms of bariatric surgery. AREAS OF CONTROVERSY The extent to which modified gut hormone secretion is also responsible for remission of diabetes after bariatric surgery is contested, as severe calorie restriction alone can restore insulin secretion. GROWING POINTS Many gut hormone-based drugs are being developed for obesity. AREAS TIMELY FOR DEVELOPING RESEARCH If suitable drugs receive marketing authorization, it will be important to discover whether their combined use, mimicking the hormonal milieu after bariatric surgery, can safely cause weight loss and metabolic benefits of similar magnitude to those resulting from bariatric surgery.
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Abstract
An L-RNA aptamer was developed that binds the natural D-form of the HIV-1 trans-activation responsive (TAR) RNA. The aptamer initially was obtained as a D-aptamer against L-TAR RNA through in vitro selection. Then the corresponding L-aptamer was prepared by chemical synthesis and used to bind the desired target. The L-aptamer binds D-TAR RNA with a Kd of 100 nM. It binds D-TAR exclusively at the six-nucleotide distal loop, but does so through tertiary interactions rather than simple Watson-Crick pairing. This complex is the first example of two nucleic acids molecules of opposing chirality that interact through a mode of binding other than primary structure. Binding of the L-aptamer to D-TAR RNA inhibits formation of the Tat-TAR ribonucleoprotein complex that is essential for TAR function. This suggests that L-aptamers, which are intrinsically resistant to degradation by ribonucleases, might be pursued as an alternative to antisense oligonucleotides to target structured RNAs of biological or therapeutic interest.
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Affiliation(s)
- Jonathan T. Sczepanski
- Departments of Chemistry and Molecular Biology and The Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, United States
| | - Gerald F. Joyce
- Departments of Chemistry and Molecular Biology and The Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, United States
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Fung JNT, Jeffery PL, Lee JD, Seim I, Roche D, Obermair A, Chopin LK, Chen C. Silencing of ghrelin receptor expression inhibits endometrial cancer cell growth in vitro and in vivo. Am J Physiol Endocrinol Metab 2013; 305:E305-13. [PMID: 23736537 DOI: 10.1152/ajpendo.00156.2013] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Ghrelin is a 28-amino acid peptide hormone produced predominantly in the stomach but also in a range of normal cell types and tumors, where it has endocrine, paracrine, and autocrine roles. Previously, we have demonstrated that ghrelin has proliferative and antiapoptotic effects in endometrial cancer cell lines, suggesting a potential role in promoting tumor growth. In the present study, we investigated the effect of ghrelin receptor, GHSR, and gene silencing in vitro and in vivo and characterized ghrelin and GHSR1a protein expression in human endometrial tumors. GHSR gene silencing was achieved in the Ishikawa and KLE endometrial cancer cell lines, using a lentiviral short-hairpin RNA targeting GHSR. The effects of GHSR1a knockdown were further analyzed in vivo using the Ishikawa cell line in a NOD/SCID xenograft model. Cell proliferation was reduced in cultured GHSR1a knockdown Ishikawa and KLE cells compared with scrambled controls in the absence of exogenously applied ghrelin and in response to exogenous ghrelin (1,000 nM). The tumor volumes were reduced significantly in GHSR1a knockdown Ishikawa mouse xenograft tumors compared with scrambled control tumours. Using immunohistochemistry, we demonstrated that ghrelin and GHSR1a are expressed in benign and cancerous glands in human endometrial tissue specimens, although there was no correlation between the intensity of staining and cancer grade. These data indicate that downregulation of GHSR expression significantly inhibits endometrial cancer cell line and mouse xenograft tumour growth. This is the first preclinical evidence that downregulation of GHSR may be therapeutic in endometrial cancer.
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Affiliation(s)
- Jenny N T Fung
- School of Biomedical Sciences, University of Queensland, St. Lucia, Queensland, Australia
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Teubner BJW, Bartness TJ. Anti-ghrelin Spiegelmer inhibits exogenous ghrelin-induced increases in food intake, hoarding, and neural activation, but not food deprivation-induced increases. Am J Physiol Regul Integr Comp Physiol 2013; 305:R323-33. [PMID: 23804279 DOI: 10.1152/ajpregu.00097.2013] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Circulating concentrations of the stomach-derived "hunger-peptide" ghrelin increase in direct proportion to the time since the last meal. Exogenous ghrelin also increases food intake in rodents and humans, suggesting ghrelin may increase post-fast ingestive behaviors. Food intake after food deprivation is increased by laboratory rats and mice, but not by humans (despite dogma to the contrary) or by Siberian hamsters; instead, humans and Siberian hamsters increase food hoarding, suggesting the latter as a model of fasting-induced changes in human ingestive behavior. Exogenous ghrelin markedly increases food hoarding by ad libitum-fed Siberian hamsters similarly to that after food deprivation, indicating sufficiency. Here, we tested the necessity of ghrelin to increase food foraging, food hoarding, and food intake, and neural activation [c-Fos immunoreactivity (c-Fos-ir)] using anti-ghrelin Spiegelmer NOX-B11-2 (SPM), an l-oligonucleotide that specifically binds active ghrelin, inhibiting peptide-receptor interaction. SPM blocked exogenous ghrelin-induced increases in food hoarding the first 2 days after injection, and foraging and food intake at 1-2 h and 2-4 h, respectively, and inhibited hypothalamic c-Fos-ir. SPM given every 24 h across 48-h food deprivation inconsistently inhibited food hoarding after refeeding and c-Fos-ir, similarly to inabilities to do so in laboratory rats and mice. These results suggest that ghrelin may not be necessary for food deprivation-induced foraging and hoarding and neural activation. A possible compensatory response, however, may underlie these findings because SPM treatment led to marked increases in circulating ghrelin concentrations. Collectively, these results show that SPM can block exogenous ghrelin-induced ingestive behaviors, but the necessity of ghrelin for food deprivation-induced ingestive behaviors remains unclear.
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Affiliation(s)
- Brett J W Teubner
- Department of Biology and Obesity Reversal Center, Georgia State University, Atlanta, Georgia
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Li Z, Li Y, Zhang W. Ghrelin receptor in energy homeostasis and obesity pathogenesis. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2013; 114:45-87. [PMID: 23317782 DOI: 10.1016/b978-0-12-386933-3.00002-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The ghrelin receptor, also known as growth hormone secretagogue receptor (GHS-R), was identified in porcine and rat anterior pituitary membranes, where the synthetic secretagogue MK-0677 causes amplified pulsatile growth hormone (GH) release. In addition to its function in the stimulation of GH secretion, ghrelin, the natural ligand of ghrelin receptor is now recognized as a peptide hormone with fundamental influence on energy homeostasis. Despite the potential existence of multiple subtypes of ghrelin receptor, the effects of ghrelin on energy metabolism, obesity, and diabetes are mediated by its classical receptor GHS-R1a, whose activation requires the n-octanoylation of ghrelin. Here we review the current understanding of the role of the ghrelin receptor in the regulation of energy homeostasis. An overview of the ghrelin receptor is presented first, followed by the discussion on its effects on food intake, glucose homeostasis, and lipid metabolism. Finally, potential strategies for treating obesity and diabetes via manipulation of the ghrelin/ghrelin receptor axis are explored.
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Affiliation(s)
- Ziru Li
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Peking University, Beijing, China
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Abstract
Ghrelin was discovered in 1999 as growth hormone secretagouge released from the gut. Soon after it was recognized that ghrelin is a fundamental driver of appetite in rodents and humans and that its mode of action requires alteration of hypothalamic circuit function. Here we review aspects of ghrelin's action that revolve around the central nervous system with the goal to highlight these pathways in integrative physiology of metabolism regulation including ghrelin's cross-talk with the action of the adipose hormone, leptin.
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Affiliation(s)
- Alfonso Abizaid
- Department of Neuroscience, Carlton University, Ottawa, ON, Canada
| | - Tamas L. Horvath
- Program in Integrative Cell Signaling and Neurobiology of Metabolism, Section of Comparative Medicine, Yale University School of Medicine, New Haven, CT, USA
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The receptive function of hypothalamic and brainstem centres to hormonal and nutrient signals affecting energy balance. Proc Nutr Soc 2012; 71:463-77. [PMID: 22931748 DOI: 10.1017/s0029665112000778] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The hypothalamic arcuate nucleus (ARC) and the area postrema (AP) represent targets for hormonal and metabolic signals involved in energy homoeostasis, e.g. glucose, amylin, insulin, leptin, peptide YY (PYY), glucagon-like peptide 1 (GLP-1) and ghrelin. Orexigenic neuropeptide Y expressing ARC neurons are activated by food deprivation and inhibited by feeding in a nutrient-dependent manner. PYY and leptin also reverse or prevent fasting-induced activation of the ARC. Interestingly, hypothalamic responses to fasting are blunted in different models of obesity (e.g. diet-induced obesity (DIO) or late-onset obesity). The AP also responds to feeding-related signals. The pancreatic hormone amylin acts via the AP to control energy intake. Amylin-sensitive AP neurons are also glucose-responsive. Furthermore, diet-derived protein attenuates amylin responsiveness suggesting a modulation of AP sensitivity by macronutrient supply. This review gives an overview of the receptive function of the ARC and the AP to hormonal and nutritional stimuli involved in the control of energy balance and the possible implications in the context of obesity. Collectively, there is consistency between the neurophysiological actions of these stimuli and their effects on energy homoeostasis under experimental conditions. However, surprisingly little progress has been made in the development of effective pharmacological approaches against obesity. A promising way to improve effectiveness involves combination treatments (e.g. amylin/leptin agonists). Hormonal alterations (e.g. GLP-1 and PYY) are also considered to mediate body weight loss observed in obese patients receiving bariatric surgery. The effects of hormonal and nutritional signals and their interactions might hold the potential to develop poly-mechanistic therapeutic strategies against obesity.
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Identification of spirocyclic piperidine-azetidine inverse agonists of the ghrelin receptor. Bioorg Med Chem Lett 2012; 22:4281-7. [DOI: 10.1016/j.bmcl.2012.05.024] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2012] [Revised: 05/04/2012] [Accepted: 05/08/2012] [Indexed: 12/27/2022]
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Olea C, Horning DP, Joyce GF. Ligand-dependent exponential amplification of a self-replicating L-RNA enzyme. J Am Chem Soc 2012; 134:8050-3. [PMID: 22551009 DOI: 10.1021/ja302197x] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A nuclease-resistant RNA enzyme, constructed entirely from L-ribonucleotides, was shown to undergo ligand-dependent, self-sustained replication with exponential growth. The catalytic motif is based on a previously described RNA ligase that can undergo either self- or cross-replication but had been limited in its application to ligand sensing due to its susceptibility to degradation by ribonucleases. The self-replicating RNA enzyme and its RNA substrates were prepared synthetically from either D- or L-nucleoside phosphoramidites. The D and L reaction systems undergo isothermal, ligand-dependent exponential amplification in the same manner, but only the l system is impervious to ribonucleases and can operate, for example, in the presence of human serum. This system has potential for the quantitative detection of various ligands that are present within biological or environmental samples. In addition, this work provides the first demonstration of the self-sustained exponential amplification of nonbiological molecules.
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Affiliation(s)
- Charles Olea
- Department of Chemistry, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, United States
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Cardona Cano S, Merkestein M, Skibicka KP, Dickson SL, Adan RAH. Role of ghrelin in the pathophysiology of eating disorders: implications for pharmacotherapy. CNS Drugs 2012; 26:281-96. [PMID: 22452525 DOI: 10.2165/11599890-000000000-00000] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Ghrelin is the only known circulating orexigenic hormone. It increases food intake by interacting with hypothalamic and brainstem circuits involved in energy balance, as well as reward-related brain areas. A heightened gut-brain ghrelin axis is an emerging feature of certain eating disorders such as anorexia nervosa and Prader-Willi syndrome. In common obesity, ghrelin levels are lowered, whereas post-meal ghrelin levels remain higher than in lean individuals. Agents that interfere with ghrelin signalling have therapeutic potential for eating disorders, including obesity. However, most of these drugs are only in the preclinical phase of development. Data obtained so far suggest that ghrelin agonists may have potential in the treatment of anorexia nervosa, while ghrelin antagonists seem promising for other eating disorders such as obesity and Prader-Willi syndrome. However, large clinical trials are needed to evaluate the efficacy and safety of these drugs.
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D'Alonzo D, Guaragna A, Palumbo G. Exploring the role of chirality in nucleic acid recognition. Chem Biodivers 2012; 8:373-413. [PMID: 21404424 DOI: 10.1002/cbdv.201000303] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The study of the base-pairing properties of nucleic acids with sugar moieties in the backbone belonging to the L-series (β-L-DNA, β-L-RNA, and their analogs) are reviewed. The major structural factors underlying the formation of stable heterochiral complexes obtained by incorporation of modified nucleotides into natural duplexes, or by hybridization between homochiral strands of opposite sense of chirality are highlighted. In addition, the perspective use of L-nucleic acids as candidates for various therapeutic applications, or as tools for both synthetic biology and etiology-oriented investigations on the structure and stereochemistry of natural nucleic acids is discussed.
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Affiliation(s)
- Daniele D'Alonzo
- Dipartimento di Chimica Organica e Biochimica, Università di Napoli Federico II, Complesso Universitario Monte Sant'Angelo, via Cinthia, 4, I-80126 Napoli.
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Meyer C, Eydeler K, Magbanua E, Zivkovic T, Piganeau N, Lorenzen I, Grötzinger J, Mayer G, Rose-John S, Hahn U. Interleukin-6 receptor specific RNA aptamers for cargo delivery into target cells. RNA Biol 2012; 9:67-80. [PMID: 22258147 PMCID: PMC3342945 DOI: 10.4161/rna.9.1.18062] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Aptamers represent an emerging strategy to deliver cargo molecules, including dyes, drugs, proteins or even genes, into specific target cells. Upon binding to specific cell surface receptors aptamers can be internalized, for example by macropinocytosis or receptor mediated endocytosis. Here we report the in vitro selection and characterization of RNA aptamers with high affinity (Kd = 20 nM) and specificity for the human IL-6 receptor (IL-6R). Importantly, these aptamers trigger uptake without compromising the interaction of IL-6R with its natural ligands the cytokine IL-6 and glycoprotein 130 (gp130). We further optimized the aptamers to obtain a shortened, only 19-nt RNA oligonucleotide retaining all necessary characteristics for high affinity and selective recognition of IL-6R on cell surfaces. Upon incubation with IL-6R presenting cells this aptamer was rapidly internalized. Importantly, we could use our aptamer, to deliver bulky cargos, exemplified by fluorescently labeled streptavidin, into IL-6R presenting cells, thereby setting the stage for an aptamer-mediated escort of drug molecules to diseased cell populations or tissues.
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Affiliation(s)
- Cindy Meyer
- Institute for Biochemistry and Molecular Biology; Chemistry Department; MIN-Faculty; Hamburg University; Hamburg, Germany
| | - Katja Eydeler
- Institute for Biochemistry and Molecular Biology; Chemistry Department; MIN-Faculty; Hamburg University; Hamburg, Germany
| | - Eileen Magbanua
- Institute for Biochemistry and Molecular Biology; Chemistry Department; MIN-Faculty; Hamburg University; Hamburg, Germany
| | - Tijana Zivkovic
- Institute for Biochemistry and Molecular Biology; Chemistry Department; MIN-Faculty; Hamburg University; Hamburg, Germany
| | - Nicolas Piganeau
- Institute for Biochemistry and Molecular Biology; Chemistry Department; MIN-Faculty; Hamburg University; Hamburg, Germany
| | - Inken Lorenzen
- Institute of Biochemistry; Medical Faculty; Christian-Albrechts-University; Kiel, Germany
| | - Joachim Grötzinger
- Institute of Biochemistry; Medical Faculty; Christian-Albrechts-University; Kiel, Germany
| | - Günter Mayer
- Life and Medical Sciences Institute; University of Bonn; Bonn, Germany
| | - Stefan Rose-John
- Institute of Biochemistry; Medical Faculty; Christian-Albrechts-University; Kiel, Germany
| | - Ulrich Hahn
- Institute for Biochemistry and Molecular Biology; Chemistry Department; MIN-Faculty; Hamburg University; Hamburg, Germany
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Abstract
Ghrelin is the only potent orexigenic peptide in circulation. It stimulates food intake and leads to positive energy balance, adipogenesis, and body weight gain. However, the physiological significance of ghrelin in the regulation of energy homeostasis is controversial, since loss of ghrelin function in rodents does not necessarily lead to anorexia and weight loss. In this chapter, we discuss the metabolic function of ghrelin and are highlighting recent findings including the discovery and function of ghrelin-acylating enzyme ghrelin O-acyltransferase (GOAT). Based on available published data, we conclude that ghrelin is a principally important endogenous regulator of energy balance, which however may affect both food intake and systemic metabolism via independent mechanisms. Importantly, ghrelin, when acylated by GOAT, might represent a key molecular link between the sensing of consumed calories and the neuroendocrine control of energy homeostasis. Thus, agents antagonizing the action of ghrelin may have therapeutic potential in the therapy of obesity.
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