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Li X, Lu H, Ji M, Sun K, Pu F, Ding Y, Hu A. Synthesis and biological properties of maleimide-based macrocyclic lactone enediynes. Org Biomol Chem 2022; 20:5481-5488. [PMID: 35775821 DOI: 10.1039/d2ob00571a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Natural enediyne antibiotics are powerful DNA-cleavage agents due to the presence of the highly reactive hex-3-ene-1,5-diyne units. However, the complicated chemical structure and thermal instability make their synthesis, derivatization, and storage challenging. Heterocycle-fused enediynes, which exhibit strong antineoplastic activity, are promising analogues of natural enediynes for medicinal applications. To this end, a series of maleimide-based enediynes with macrocyclic lactone moieties were synthesized through the Sonagashira coupling reaction. Differential scanning calorimetry and electron paramagnetic resonance results showed that these macrocyclic enediynes exhibited a rather low onset temperature and the ability to generate radicals at physiological temperature. In addition, the structure-activity relationship of enediynes was analyzed by changing the ring size and the substituents on the propargyl group. Cellular experiments indicated that the diradicals produced by these enediynes efficiently cleaved DNA and disrupted the cell cycle distribution, and consequently induced tumor cell death via an apoptosis pathway at low half inhibitory concentrations. Computational studies suggested that the maleimide moiety promoted the propargyl-allenyl rearrangement of the cyclic enediyne, enabling the generation of diradical species through the Myers-Saito cyclization, and then abstracted hydrogen atoms from the H-donors.
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Affiliation(s)
- Xiaoxuan Li
- Shanghai Key Laboratory of Advanced Polymeric Materials, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237, China.
| | - Haotian Lu
- Shanghai Key Laboratory of Advanced Polymeric Materials, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237, China.
| | - Mingming Ji
- Shanghai Key Laboratory of Advanced Polymeric Materials, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237, China.
| | - Ke Sun
- Shanghai Key Laboratory of Advanced Polymeric Materials, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237, China.
| | - Fangxu Pu
- Shanghai Key Laboratory of Advanced Polymeric Materials, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237, China.
| | - Yun Ding
- Shanghai Key Laboratory of Advanced Polymeric Materials, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237, China.
| | - Aiguo Hu
- Shanghai Key Laboratory of Advanced Polymeric Materials, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237, China.
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2
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Rosenblum SL, Garner AL. RiPCA: An Assay for the Detection of RNA-Protein Interactions in Live Cells. Curr Protoc 2022; 2:e358. [PMID: 35113480 PMCID: PMC8852372 DOI: 10.1002/cpz1.358] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Increasing interest in studying and modulating the interactions between RNAs and their RNA-binding proteins has indicated the need for enabling technologies. Existing means of detecting RNA-protein interactions (RPIs) are often limited to biochemical or post-lysis methods or cell-based methods that require the addition of an RNA-based affinity tag, such as the MS2 hairpin, precluding them from use in detecting small or highly processed RNAs. Taking advantage of bioorthogonal chemistry- and split-luciferase-based technologies, we developed an assay for the detection of RPIs in live cells. This article details the protocol and design considerations for RiPCA, or RNA interaction with Protein-mediated Complementation Assay. © 2022 Wiley Periodicals LLC.
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Affiliation(s)
| | - Amanda L. Garner
- Program in Chemical Biology, University of Michigan, Ann Arbor, MI,Department of Medicinal Chemistry, College of Pharmacy, University of Michigan, Ann Arbor, MI
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3
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Kallemeijn WW, Lanyon-Hogg T, Panyain N, Goya Grocin A, Ciepla P, Morales-Sanfrutos J, Tate EW. Proteome-wide analysis of protein lipidation using chemical probes: in-gel fluorescence visualization, identification and quantification of N-myristoylation, N- and S-acylation, O-cholesterylation, S-farnesylation and S-geranylgeranylation. Nat Protoc 2021; 16:5083-5122. [PMID: 34707257 DOI: 10.1038/s41596-021-00601-6] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Accepted: 07/05/2021] [Indexed: 02/08/2023]
Abstract
Protein lipidation is one of the most widespread post-translational modifications (PTMs) found in nature, regulating protein function, structure and subcellular localization. Lipid transferases and their substrate proteins are also attracting increasing interest as drug targets because of their dysregulation in many disease states. However, the inherent hydrophobicity and potential dynamic nature of lipid modifications makes them notoriously challenging to detect by many analytical methods. Chemical proteomics provides a powerful approach to identify and quantify these diverse protein modifications by combining bespoke chemical tools for lipidated protein enrichment with quantitative mass spectrometry-based proteomics. Here, we report a robust and proteome-wide approach for the exploration of five major classes of protein lipidation in living cells, through the use of specific chemical probes for each lipid PTM. In-cell labeling of lipidated proteins is achieved by the metabolic incorporation of a lipid probe that mimics the specific natural lipid, concomitantly wielding an alkyne as a bio-orthogonal labeling tag. After incorporation, the chemically tagged proteins can be coupled to multifunctional 'capture reagents' by using click chemistry, allowing in-gel fluorescence visualization or enrichment via affinity handles for quantitative chemical proteomics based on label-free quantification (LFQ) or tandem mass-tag (TMT) approaches. In this protocol, we describe the application of lipid probes for N-myristoylation, N- and S-acylation, O-cholesterylation, S-farnesylation and S-geranylgeranylation in multiple cell lines to illustrate both the workflow and data obtained in these experiments. We provide detailed workflows for method optimization, sample preparation for chemical proteomics and data processing. A properly trained researcher (e.g., technician, graduate student or postdoc) can complete all steps from optimizing metabolic labeling to data processing within 3 weeks. This protocol enables sensitive and quantitative analysis of lipidated proteins at a proteome-wide scale at native expression levels, which is critical to understanding the role of lipid PTMs in health and disease.
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Affiliation(s)
- Wouter W Kallemeijn
- Department of Chemistry, Imperial College London, Molecular Sciences Research Hub, London, UK
- The Francis Crick Institute, London, UK
| | - Thomas Lanyon-Hogg
- Department of Chemistry, Imperial College London, Molecular Sciences Research Hub, London, UK
- Department of Pharmacology, University of Oxford, Oxford, UK
| | - Nattawadee Panyain
- Department of Chemistry, Imperial College London, Molecular Sciences Research Hub, London, UK
- Global Health Institute, Faculty of Life Sciences, Swiss Federal Institute of Technology Lausanne (EPFL), Lausanne, Switzerland
| | - Andrea Goya Grocin
- Department of Chemistry, Imperial College London, Molecular Sciences Research Hub, London, UK
- The Francis Crick Institute, London, UK
| | - Paulina Ciepla
- Department of Chemistry, Imperial College London, Molecular Sciences Research Hub, London, UK
- Institute of Chemical Sciences and Engineering (ISIC), Swiss Federal Institute of Technology Lausanne (EPFL), Lausanne, Switzerland
| | - Julia Morales-Sanfrutos
- Department of Chemistry, Imperial College London, Molecular Sciences Research Hub, London, UK
- Proteomics Unit, Biotechnology Programme, Spanish National Cancer Research Centre (CNIO), Madrid, Spain
| | - Edward W Tate
- Department of Chemistry, Imperial College London, Molecular Sciences Research Hub, London, UK.
- The Francis Crick Institute, London, UK.
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4
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Davis TR, Pierce MR, Novak SX, Hougland JL. Ghrelin octanoylation by ghrelin O-acyltransferase: protein acylation impacting metabolic and neuroendocrine signalling. Open Biol 2021; 11:210080. [PMID: 34315274 PMCID: PMC8316800 DOI: 10.1098/rsob.210080] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The acylated peptide hormone ghrelin impacts a wide range of physiological processes but is most well known for controlling hunger and metabolic regulation. Ghrelin requires a unique posttranslational modification, serine octanoylation, to bind and activate signalling through its cognate GHS-R1a receptor. Ghrelin acylation is catalysed by ghrelin O-acyltransferase (GOAT), a member of the membrane-bound O-acyltransferase (MBOAT) enzyme family. The ghrelin/GOAT/GHS-R1a system is defined by multiple unique aspects within both protein biochemistry and endocrinology. Ghrelin serves as the only substrate for GOAT within the human proteome and, among the multiple hormones involved in energy homeostasis and metabolism such as insulin and leptin, acts as the only known hormone in circulation that directly stimulates appetite and hunger signalling. Advances in GOAT enzymology, structural modelling and inhibitor development have revolutionized our understanding of this enzyme and offered new tools for investigating ghrelin signalling at the molecular and organismal levels. In this review, we briefly summarize the current state of knowledge regarding ghrelin signalling and ghrelin/GOAT enzymology, discuss the GOAT structural model in the context of recently reported MBOAT enzyme superfamily member structures, and highlight the growing complement of GOAT inhibitors that offer options for both ghrelin signalling studies and therapeutic applications.
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Affiliation(s)
- Tasha R Davis
- Department of Chemistry, Syracuse University, Syracuse, NY 13244 USA
| | - Mariah R Pierce
- Department of Chemistry, Syracuse University, Syracuse, NY 13244 USA
| | - Sadie X Novak
- Department of Chemistry, Syracuse University, Syracuse, NY 13244 USA
| | - James L Hougland
- Department of Chemistry, Syracuse University, Syracuse, NY 13244 USA.,BioInspired Syracuse, Syracuse University, Syracuse, NY 13244 USA
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5
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Suazo KF, Park KY, Distefano MD. A Not-So-Ancient Grease History: Click Chemistry and Protein Lipid Modifications. Chem Rev 2021; 121:7178-7248. [PMID: 33821625 DOI: 10.1021/acs.chemrev.0c01108] [Citation(s) in RCA: 40] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Protein lipid modification involves the attachment of hydrophobic groups to proteins via ester, thioester, amide, or thioether linkages. In this review, the specific click chemical reactions that have been employed to study protein lipid modification and their use for specific labeling applications are first described. This is followed by an introduction to the different types of protein lipid modifications that occur in biology. Next, the roles of click chemistry in elucidating specific biological features including the identification of lipid-modified proteins, studies of their regulation, and their role in diseases are presented. A description of the use of protein-lipid modifying enzymes for specific labeling applications including protein immobilization, fluorescent labeling, nanostructure assembly, and the construction of protein-drug conjugates is presented next. Concluding remarks and future directions are presented in the final section.
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Affiliation(s)
- Kiall F Suazo
- Department of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Keun-Young Park
- Department of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Mark D Distefano
- Department of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455, United States
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6
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Ahmad A, Akram W, Bashir Z, Shahzadi I, Wang R, Abbas HMK, Hu D, Ahmed S, Xu X, Li G, Wu T. Functional and Structural Analysis of a Novel Acyltransferase from Pathogenic Phytophthora melonis. ACS OMEGA 2021; 6:1797-1808. [PMID: 33521421 PMCID: PMC7841795 DOI: 10.1021/acsomega.0c03186] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Accepted: 12/15/2020] [Indexed: 05/07/2023]
Abstract
This investigation characterizes an acyltransferase enzyme responsible for the pathogenicity of Phytophthora melonis. The protein was characterized in vitro for its physicochemical properties. The biochemical characterization, including thermal and pH stability, revealed the 35 °C temperature and 7.0 pH as the optimum conditions for the enzyme. Applying the Tween-80 solution enhanced the activity up to 124.9%. Comprehensive structural annotation revealed two domains, A (ranging from residues 260 to 620) and B (ranging from 141 to 219). Domain A had transglutaminase (T-Gase) elicitor properties, while B possessed antifreeze features. Rigorous sequence characterization of the acyltransferase tagged it as a low-temperature-resistant protein. Further, the taxonomic distribution analysis of the protein highlighted three genera in Oomycetes, i.e., Pythium, Phytophthora, and Plasmopara, bearing this protein. However, some taxonomic groups other than Oomycetes (i.e., archaea and bacteria) also contained the protein. Functional studies of structurally analogous proteins spanned 10 different taxonomic groups. These revealed TGase elicitors (10%), phytopathogen effector proteins RxLR (4%), transporter family proteins (3%), and endonucleases (1%). Other analogues having one percent of their individual share were HIV tat-specific factor 1, protocadherin fat 4, transcription factor 1, and 3-hydroxyisobutyrate dehydrogenase. Because the plant infection by P. melonis is a complex process regulated by a profusion of extracellular signals secreted by both host plants and the pathogen, this study will be of help in interpreting the cross-talk in the host-pathogen system.
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Affiliation(s)
- Aqeel Ahmad
- Vegetable
Research Institute, Guangdong Academy of Agricultural Sciences/Guangdong
Key Laboratory for New Technology Research of Vegetables, Guangzhou 510640, China
| | - Waheed Akram
- Vegetable
Research Institute, Guangdong Academy of Agricultural Sciences/Guangdong
Key Laboratory for New Technology Research of Vegetables, Guangzhou 510640, China
| | - Zoobia Bashir
- National
Laboratory of Solid State Microstructures, Department of Physics, Nanjing University, 22 Hankou Road, Nanjing, Jiangsu 210093, China
| | - Iqra Shahzadi
- School
of Resource and Environmental Science, Wuhan
University, Wuhan 430072, Hubei, China
| | - Rui Wang
- Vegetable
Research Institute, Guangdong Academy of Agricultural Sciences/Guangdong
Key Laboratory for New Technology Research of Vegetables, Guangzhou 510640, China
| | - Hafiz Muhammad Khalid Abbas
- Vegetable
Research Institute, Guangdong Academy of Agricultural Sciences/Guangdong
Key Laboratory for New Technology Research of Vegetables, Guangzhou 510640, China
| | - Du Hu
- Vegetable
Research Institute, Guangdong Academy of Agricultural Sciences/Guangdong
Key Laboratory for New Technology Research of Vegetables, Guangzhou 510640, China
| | - Shakeel Ahmed
- Instituto
de Farmacia, Facultad de Ciencias, Universidad
Austral de Chile, Campus
Isla Teja, Valdivia 5090000, Chile
| | - Xiaomei Xu
- Vegetable
Research Institute, Guangdong Academy of Agricultural Sciences/Guangdong
Key Laboratory for New Technology Research of Vegetables, Guangzhou 510640, China
| | - Guihua Li
- Vegetable
Research Institute, Guangdong Academy of Agricultural Sciences/Guangdong
Key Laboratory for New Technology Research of Vegetables, Guangzhou 510640, China
| | - Tingquan Wu
- Vegetable
Research Institute, Guangdong Academy of Agricultural Sciences/Guangdong
Key Laboratory for New Technology Research of Vegetables, Guangzhou 510640, China
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7
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Iyer MR, Wood CM, Kunos G. Recent progress in the discovery of ghrelin O-acyltransferase (GOAT) inhibitors. RSC Med Chem 2020; 11:1136-1144. [PMID: 33479618 PMCID: PMC7651998 DOI: 10.1039/d0md00210k] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Accepted: 08/03/2020] [Indexed: 12/29/2022] Open
Abstract
Ghrelin is a stomach-derived peptide hormone which stimulates appetite. For ghrelin to exert its orexigenic effect, octanoylation on the serine-3 residue of this gut-brain peptide is essential. The octanoylation of ghrelin is mediated by a unique acyltransferase enzyme known as ghrelin O-acyltransferase (GOAT). Thus modulating this enzyme offers viable approaches to alter feeding behaviors. Over the past decade, several small-molecule based approaches have appeared dealing with the discovery of compounds able to modulate this enzyme for the treatment of obesity and type 2 diabetes. Drug discovery efforts from academic groups and several pharmaceutical companies have fielded compounds having efficacy in altering acylated ghrelin levels in animal models but to date, compounds modulating the activity of the GOAT enzyme do not yet represent clinical options. This mini-review covers the drug discovery approaches of the last decade since the discovery of the GOAT enzyme.
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Affiliation(s)
- Malliga R Iyer
- Medicinal Chemistry Core and Laboratory of Physiologic Studies , National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health (NIAAA/NIH) , 5625 Fishers Lane , Rockville , MD 20852 , USA . ; Tel: +301 443 2807
| | - Casey M Wood
- Medicinal Chemistry Core and Laboratory of Physiologic Studies , National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health (NIAAA/NIH) , 5625 Fishers Lane , Rockville , MD 20852 , USA . ; Tel: +301 443 2807
| | - George Kunos
- Medicinal Chemistry Core and Laboratory of Physiologic Studies , National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health (NIAAA/NIH) , 5625 Fishers Lane , Rockville , MD 20852 , USA . ; Tel: +301 443 2807
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8
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Moose JE, Leets KA, Mate NA, Chisholm JD, Hougland JL. An overview of ghrelin O-acyltransferase inhibitors: a literature and patent review for 2010-2019. Expert Opin Ther Pat 2020; 30:581-593. [PMID: 32564644 DOI: 10.1080/13543776.2020.1776263] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
INTRODUCTION The peptide hormone ghrelin regulates physiological processes associated with energy homeostasis such as appetite, insulin signaling, glucose metabolism, and adiposity. Ghrelin has also been implicated in a growing number of neurological pathways involved in stress response and addiction behavior. For ghrelin to bind the growth hormone secretagogue receptor 1a (GHS-R1a) and activate signaling, the hormone must first be octanoylated on a specific serine side chain. This key transformation is performed by the enzyme ghrelin O-acyltransferase (GOAT), and therefore GOAT inhibitors may be useful in treating disorders related to ghrelin signaling such as diabetes, obesity, and related metabolic syndromes. AREAS COVERED This report covers ghrelin and GOAT as potential therapeutic targets and summarizes work on GOAT inhibitors through the end of 2019, highlighting recent successes with both peptidomimetics and small molecule GOAT inhibitors as potent modulators of GOAT-catalyzed ghrelin octanoylation. EXPERT OPINION A growing body of biochemical and structural knowledge regarding the ghrelin/GOAT system now enables multiple avenues for identifying and optimizing GOAT inhibitors. We are at the beginning of a new era with increased opportunities for leveraging ghrelin and GOAT in the understanding and treatment of multiple health conditions including diabetes, obesity, and addiction.
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Affiliation(s)
- Jacob E Moose
- Department of Chemistry and BioInspired Syracuse, Syracuse University , Syracuse, NY, USA
| | - Katelyn A Leets
- Department of Chemistry and BioInspired Syracuse, Syracuse University , Syracuse, NY, USA
| | - Nilamber A Mate
- Department of Chemistry and BioInspired Syracuse, Syracuse University , Syracuse, NY, USA
| | - John D Chisholm
- Department of Chemistry and BioInspired Syracuse, Syracuse University , Syracuse, NY, USA
| | - James L Hougland
- Department of Chemistry and BioInspired Syracuse, Syracuse University , Syracuse, NY, USA
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9
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Lanyon-Hogg T, Ritzefeld M, Sefer L, Bickel JK, Rudolf AF, Panyain N, Bineva-Todd G, Ocasio CA, O'Reilly N, Siebold C, Magee AI, Tate EW. Acylation-coupled lipophilic induction of polarisation (Acyl-cLIP): a universal assay for lipid transferase and hydrolase enzymes. Chem Sci 2019; 10:8995-9000. [PMID: 31762980 PMCID: PMC6855259 DOI: 10.1039/c9sc01785b] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2019] [Accepted: 06/16/2019] [Indexed: 12/12/2022] Open
Abstract
Posttranslational attachment of lipids to proteins is important for many cellular functions, and the enzymes responsible for these modifications are implicated in many diseases, from cancer to neurodegeneration. Lipid transferases and hydrolases are increasingly tractable therapeutic targets, but present unique challenges for high-throughput biochemical enzyme assays which hinder development of new inhibitors. We present Acylation-coupled Lipophilic Induction of Polarisation (Acyl-cLIP) as the first universally applicable biochemical lipidation assay, exploiting the hydrophobic nature of lipidated peptides to drive a polarised fluorescence readout. Acyl-cLIP allows sensitive, accurate, real-time measurement of S- or N-palmitoylation, N-myristoylation, S-farnesylation or S-geranylgeranylation. Furthermore, it is applicable to transfer and hydrolysis reactions, and we demonstrate its extension to a high-throughput screening format. We anticipate that Acyl-cLIP will greatly expedite future drug discovery efforts against these challenging targets.
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Affiliation(s)
- Thomas Lanyon-Hogg
- Department of Chemistry , Imperial College London , London , W12 0BZ , UK . ; ; Tel: +44 0207 5943752 ; Tel: +44 0207 5945821
| | - Markus Ritzefeld
- Department of Chemistry , Imperial College London , London , W12 0BZ , UK . ; ; Tel: +44 0207 5943752 ; Tel: +44 0207 5945821
| | - Lea Sefer
- Division of Structural Biology , Wellcome Centre for Human Genetics , University of Oxford , Oxford , OX3 7BN , UK
| | - Jasmine K Bickel
- Department of Chemistry , Imperial College London , London , W12 0BZ , UK . ; ; Tel: +44 0207 5943752 ; Tel: +44 0207 5945821
| | - Amalie F Rudolf
- Division of Structural Biology , Wellcome Centre for Human Genetics , University of Oxford , Oxford , OX3 7BN , UK
| | - Nattawadee Panyain
- Department of Chemistry , Imperial College London , London , W12 0BZ , UK . ; ; Tel: +44 0207 5943752 ; Tel: +44 0207 5945821
| | | | | | | | - Christian Siebold
- Division of Structural Biology , Wellcome Centre for Human Genetics , University of Oxford , Oxford , OX3 7BN , UK
| | - Anthony I Magee
- Molecular Medicine Section , National Heart & Lung Institute , Imperial College London , London , SW7 2AZ , UK
| | - Edward W Tate
- Department of Chemistry , Imperial College London , London , W12 0BZ , UK . ; ; Tel: +44 0207 5943752 ; Tel: +44 0207 5945821
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10
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Sherman EJ, Lorenz DA, Garner AL. Click Chemistry-Mediated Complementation Assay for RNA-Protein Interactions. ACS COMBINATORIAL SCIENCE 2019; 21:522-527. [PMID: 31181888 DOI: 10.1021/acscombsci.9b00071] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Click chemistry-based assays are a growing class of biochemical assay for facilitating the discovery of modulators of important biological processes. To date, most have relied on the use of immobilized biomolecules, which increases the cost of the assay and decreases throughput because of the necessary washing steps. To overcome these challenges, we have developed a click chemistry-mediated complementation assay that retains many of the advantages of the previous technology, including catalytic signal amplification for assay robustness and applicability to full-length biomolecules, but that can be performed in a homogeneous format. As demonstration of this methodology, we have developed a new high-throughput screening method for RNA-protein interactions using the interaction of Lin28 with the pre-microRNA, prelet-7, as a model.
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11
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Ghrelin octanoylation by ghrelin O-acyltransferase: Unique protein biochemistry underlying metabolic signaling. Biochem Soc Trans 2019; 47:169-178. [PMID: 30626708 DOI: 10.1042/bst20180436] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2018] [Revised: 11/26/2018] [Accepted: 11/28/2018] [Indexed: 02/08/2023]
Abstract
Ghrelin is a small peptide hormone that requires a unique post-translational modification, serine octanoylation, to bind and activate the GHS-R1a receptor. Ghrelin signaling is implicated in a variety of neurological and physiological processes, but is most well known for its roles in controlling hunger and metabolic regulation. Ghrelin octanoylation is catalyzed by ghrelin O-acyltransferase (GOAT), a member of the membrane-bound O-acyltransferase (MBOAT) enzyme family. From the status of ghrelin as the only substrate for GOAT in the human genome to the source and requirement for the octanoyl acyl donor, the ghrelin-GOAT system is defined by multiple unique aspects within both protein biochemistry and endocrinology. In this review, we examine recent advances in our understanding of the interactions and mechanisms leading to ghrelin modification by GOAT, discuss the potential sources for the octanoyl acyl donor required for ghrelin's activation, and summarize the current landscape of molecules targeting ghrelin octanoylation through GOAT inhibition.
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12
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Garner AL, Lorenz DA, Gallagher EE. A click chemistry assay to identify natural product ligands for pre-microRNAs. Methods Enzymol 2019; 623:85-99. [PMID: 31239059 PMCID: PMC6631307 DOI: 10.1016/bs.mie.2019.04.020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Despite the great diversity of structure and function and relevance to human health, RNA remains an underexploited area of drug discovery. A major bottleneck toward this goal has been the identification of probes and drug leads that are specific for select RNAs and methods that will facilitate such discovery efforts. Our laboratory has recently developed an innovative approach for assaying RNA-small molecule interactions, catalytic enzyme-linked click chemistry assay or cat-ELCCA, which is a functional assay that takes advantage of the power of catalytic signal amplification combined with the selectivity and bioorthogonality of click chemistry. Importantly, through application of this platform assay technology to the challenging problem of identifying selective inhibitors of pre-microRNA maturation, we identified natural products as a potential source of such compounds. Herein we describe this methodology in addition to the downstream pipeline toward the discovery of natural product ligands for pre-microRNAs. Through cat-ELCCA, our goal is to discover novel ligands to facilitate our investigation of RNA recognition by small molecules.
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Affiliation(s)
- Amanda L Garner
- Department of Medicinal Chemistry, College of Pharmacy, University of Michigan, Ann Arbor, MI, United States; Program in Chemical Biology, University of Michigan, Ann Arbor, MI, United States.
| | - Daniel A Lorenz
- Program in Chemical Biology, University of Michigan, Ann Arbor, MI, United States
| | - Erin E Gallagher
- Department of Medicinal Chemistry, College of Pharmacy, University of Michigan, Ann Arbor, MI, United States
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13
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Lemarié F, Beauchamp E, Drouin G, Legrand P, Rioux V. Dietary caprylic acid and ghrelin O-acyltransferase activity to modulate octanoylated ghrelin functions: What is new in this nutritional field? Prostaglandins Leukot Essent Fatty Acids 2018; 135:121-127. [PMID: 30103923 DOI: 10.1016/j.plefa.2018.07.009] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/07/2018] [Revised: 07/15/2018] [Accepted: 07/16/2018] [Indexed: 12/15/2022]
Abstract
Caprylic acid (octanoic acid, C8:0) belongs to the class of medium-chain saturated fatty acids (MCFAs). Dairy products and specific oils such as coconut oil are natural sources of dietary caprylic acid. MCFAs display distinct chemico-physical and metabolic properties from those of long-chain saturated fatty acids (LCFAs ≥ 12 carbons) and potential beneficial physiological effects of dietary C8:0 have been studied for many years. More recently, caprylic acid was shown to octanoylate ghrelin, the only known peptide hormone with an orexigenic effect. Through its covalent binding to the ghrelin peptide, caprylic acid exhibits an emerging and specific role in modulating physiological functions themselves regulated by octanoylated ghrelin. Dietary caprylic acid is therefore now suspected to provide the ghrelin O-acyltransferase (GOAT) enzyme with octanoyl-CoA co-substrates necessary for the acyl modification of ghrelin. Recent studies suggest that decreasing the circulating octanoylated ghrelin level through the inhibition of GOAT activity, or simply by modulating the availability of its C8:0 substrate, might constitute a therapeutic strategy against obesity. Both dietary caprylic acid availability and GOAT activity may indeed be important to modulate octanoylated ghrelin concentration and functions. This review highlights recent findings in the field of nutrition.
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Affiliation(s)
- Fanny Lemarié
- Laboratoire de Biochimie-Nutrition Humaine, Agrocampus Ouest, Rennes, France; Centre for Molecular Medicine and Therapeutics (CMMT), The University of British Columbia, BC Children's Hospital Research Institute, Vancouver, Canada
| | - Erwan Beauchamp
- Laboratoire de Biochimie-Nutrition Humaine, Agrocampus Ouest, Rennes, France
| | - Gaëtan Drouin
- Laboratoire de Biochimie-Nutrition Humaine, Agrocampus Ouest, Rennes, France
| | - Philippe Legrand
- Laboratoire de Biochimie-Nutrition Humaine, Agrocampus Ouest, Rennes, France
| | - Vincent Rioux
- Laboratoire de Biochimie-Nutrition Humaine, Agrocampus Ouest, Rennes, France.
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14
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Abstract
Click chemistry has emerged as a powerful tool in our arsenal for unlocking new biology. This includes its utility in both chemical biology and drug discovery. An emerging application of click chemistry is in the development of biochemical assays for high-throughput screening to identify new chemical probes and drug leads. This Feature Article will discuss the advancements in click chemistry that were necessary for the development of a new class of biochemical assay, catalytic enzyme-linked click chemistry assay or cat-ELCCA. Inspired by enzyme immunoassays, cat-ELCCA was designed as a click chemistry-based amplification assay where bioorthogonally-tagged analytes and enzymes are used in place of the enzyme-linked secondary antibodies used in immunoassays. The result is a robust assay format with demonstrated applicability in several important areas of biology and drug discovery, including post-translational modifications, pre-microRNA maturation, and protein-protein and RNA-protein interactions. Through the use of cat-ELCCA and other related click chemistry-based assays, new chemical probes for interrogating promising drug targets have been discovered. These examples will be discussed, in addition to a future outlook on the impact of this approach in probe and drug discovery.
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Affiliation(s)
- Amanda L Garner
- Department of Medicinal Chemistry, College of Pharmacy, University of Michigan, 1600 Huron Parkway, NCRC B520, Ann Arbor, Michigan 48109, USA.
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15
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Lorenz DA, Kaur T, Kerk SA, Gallagher EE, Sandoval J, Garner AL. Expansion of cat-ELCCA for the Discovery of Small Molecule Inhibitors of the Pre-let-7-Lin28 RNA-Protein Interaction. ACS Med Chem Lett 2018; 9:517-521. [PMID: 29937975 PMCID: PMC6004563 DOI: 10.1021/acsmedchemlett.8b00126] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2018] [Accepted: 05/16/2018] [Indexed: 12/15/2022] Open
Abstract
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Dysregulation of
microRNA (miRNA) expression has been linked to
many human diseases; however, because of the challenges associated
with RNA-targeted drug discovery, additional approaches are needed
for probing miRNA biology. The emerging regulatory role of miRNA-binding
proteins in miRNA maturation presents such an alternative strategy.
Exploiting our laboratory’s click chemistry-based high-throughput
screening (HTS) technology, catalytic enzyme-linked click chemistry
assay or cat-ELCCA, we have designed a modular method by which to
discover new chemical tools for manipulating pre-miRNA–miRNA–binding
protein interactions. Using the pre-let-7d–Lin28 interaction
as proof-of-concept, the results presented demonstrate how HTS using
cat-ELCCA can enable the discovery of small molecules targeting RNA–protein
interactions.
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16
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Gao X, Hannoush RN. A Decade of Click Chemistry in Protein Palmitoylation: Impact on Discovery and New Biology. Cell Chem Biol 2017; 25:236-246. [PMID: 29290622 DOI: 10.1016/j.chembiol.2017.12.002] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2017] [Revised: 11/10/2017] [Accepted: 11/30/2017] [Indexed: 12/17/2022]
Abstract
Protein palmitoylation plays diverse roles in regulating the trafficking, stability, and activity of cellular proteins. The advent of click chemistry has propelled the field of protein palmitoylation forward by providing specific, sensitive, rapid, and easy-to-handle methods for studying protein palmitoylation. This year marks the 10th anniversary since the first click chemistry-based fatty acid probes for detecting protein lipid modifications were reported. The goal of this review is to highlight key biological advancements in the field of protein palmitoylation during the past 10 years. In particular, we discuss the impact of click chemistry on enabling protein palmitoylation proteomics methods, uncovering novel lipid modifications on proteins and elucidating their functions, as well as the development of non-radioactive biochemical and enzymatic assays. In addition, this review provides context for building and exploring new research avenues in protein palmitoylation through the use of clickable fatty acid probes.
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Affiliation(s)
- Xinxin Gao
- Department of Early Discovery Biochemistry, Genentech, South San Francisco, CA, USA
| | - Rami N Hannoush
- Department of Early Discovery Biochemistry, Genentech, South San Francisco, CA, USA.
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17
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Song JM, Menon A, Mitchell DC, Johnson OT, Garner AL. High-Throughput Chemical Probing of Full-Length Protein-Protein Interactions. ACS COMBINATORIAL SCIENCE 2017; 19:763-769. [PMID: 29112379 PMCID: PMC5939945 DOI: 10.1021/acscombsci.7b00128] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Human biology is regulated by a complex network of protein-protein interactions (PPIs), and disruption of this network has been implicated in many diseases. However, the targeting of PPIs remains a challenging area for chemical probe and drug discovery. Although many methodologies have been put forth to facilitate these efforts, new technologies are still needed. Current biochemical assays for PPIs are typically limited to motif-domain and domain-domain interactions, and assays that will enable the screening of full-length protein systems, which are more biologically relevant, are sparse. To overcome this barrier, we have developed a new assay technology, "PPI catalytic enzyme-linked click chemistry assay" or PPI cat-ELCCA, which utilizes click chemistry to afford catalytic signal amplification. To validate this approach, we have applied PPI cat-ELCCA to the eIF4E-4E-BP1 and eIF4E-eIF4G PPIs, key regulators of cap-dependent mRNA translation. Using these examples, we have demonstrated that PPI cat-ELCCA is amenable to full-length proteins, large (>200 kDa) and small (∼12 kDa), and is readily adaptable to automated high-throughput screening. Thus, PPI cat-ELCCA represents a powerful new tool in the toolbox of assays available to scientists interested in the targeting of disease-relevant PPIs.
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Affiliation(s)
- James M. Song
- Program in Chemical Biology, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Arya Menon
- Department of Medicinal Chemistry, College of Pharmacy, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Dylan C. Mitchell
- Program in Chemical Biology, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Oleta T. Johnson
- Program in Chemical Biology, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Amanda L. Garner
- Program in Chemical Biology, University of Michigan, Ann Arbor, Michigan 48109, United States
- Department of Medicinal Chemistry, College of Pharmacy, University of Michigan, Ann Arbor, Michigan 48109, United States
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18
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Cleverdon ER, McGovern-Gooch KR, Hougland JL. The octanoylated energy regulating hormone ghrelin: An expanded view of ghrelin's biological interactions and avenues for controlling ghrelin signaling. Mol Membr Biol 2017; 33:111-124. [PMID: 29143554 DOI: 10.1080/09687688.2017.1388930] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Ghrelin is a small peptide hormone that requires a unique post-translational modification, serine octanoylation, to bind and activate the GHS-R1a receptor. Initially demonstrated to stimulate hunger and appetite, ghrelin-dependent signaling is implicated in a variety of neurological and physiological processes influencing diseases such as diabetes, obesity, and Prader-Willi syndrome. In addition to its cognate receptor, recent studies have revealed ghrelin interacts with a range of binding partners within the bloodstream. Defining the scope of ghrelin's interactions within the body, understanding how these interactions work in concert to modulate ghrelin signaling, and developing molecular tools for controlling ghrelin signaling are essential for exploiting ghrelin for therapeutic effect. In this review, we discuss recent findings regarding the biological effects of ghrelin signaling, outline binding partners that control ghrelin trafficking and stability in circulation, and summarize the current landscape of inhibitors targeting ghrelin octanoylation.
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Affiliation(s)
| | | | - James L Hougland
- a Department of Chemistry , Syracuse University , Syracuse , NY , USA
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19
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Lorenz DA, Vander Roest S, Larsen MJ, Garner AL. Development and Implementation of an HTS-Compatible Assay for the Discovery of Selective Small-Molecule Ligands for Pre-microRNAs. SLAS DISCOVERY 2017; 23:47-54. [PMID: 28686847 DOI: 10.1177/2472555217717944] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
microRNAs (miRNAs) are small gene regulatory RNAs, and their expression has been found to be dysregulated in a number of human diseases. To facilitate the discovery of small molecules capable of selectively modulating the activity of a specific miRNA, we have utilized new high-throughput screening technology targeting Dicer-mediated pre-miRNA maturation. Pilot screening of ~50,000 small molecules and ~33,000 natural product extract libraries against pre-miR-21 processing indicated the potential of our assay for this goal, yielding a campaign Z' factor of 0.52 and an average plate signal-to-background (S/B) ratio of 13. Using two-dimensional screening against a second pre-miRNA, pre-let-7d, we evaluated the selectivity of confirmed hits. The results presented demonstrate how high-throughput screening can be used to identify selective small molecules for a target RNA.
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Affiliation(s)
- Daniel A Lorenz
- 1 Program in Chemical Biology, University of Michigan, Ann Arbor, Michigan, USA
| | - Steve Vander Roest
- 3 Center for Chemical Genomics, Life Sciences Institute, University of Michigan, Ann Arbor, Michigan, USA
| | - Martha J Larsen
- 3 Center for Chemical Genomics, Life Sciences Institute, University of Michigan, Ann Arbor, Michigan, USA
| | - Amanda L Garner
- 1 Program in Chemical Biology, University of Michigan, Ann Arbor, Michigan, USA.,2 Department of Medicinal Chemistry, College of Pharmacy, University of Michigan, Ann Arbor, Michigan, USA
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20
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Lanyon-Hogg T, Patel NV, Ritzefeld M, Boxall KJ, Burke R, Blagg J, Magee AI, Tate EW. Microfluidic Mobility Shift Assay for Real-Time Analysis of Peptide N-Palmitoylation. SLAS DISCOVERY : ADVANCING LIFE SCIENCES R & D 2017; 22:418-424. [PMID: 28296537 PMCID: PMC5453399 DOI: 10.1177/2472555216689529] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/14/2016] [Revised: 12/24/2016] [Accepted: 12/27/2016] [Indexed: 02/06/2023]
Abstract
The Hedgehog pathway is a key developmental signaling pathway but is also implicated in many types of cancer. The extracellular signaling protein Sonic hedgehog (Shh) requires dual lipidation for functional signaling, whereby N-terminal palmitoylation is performed by the enzyme Hedgehog acyltransferase (Hhat). Hhat is an attractive target for small-molecule inhibition to arrest Hedgehog signaling, and methods for assaying Hhat activity are central to understanding its function. However, all existing assays to quantify lipidation of peptides suffer limitations, such as safety hazards, high costs, extensive manual handling, restriction to stopped-assay measurements, or indirect assessment of lipidation. To address these limitations, we developed a microfluidic mobility shift assay (MSA) to analyze Shh palmitoylation. MSA allowed separation of fluorescently labeled Shh amine-substrate and palmitoylated Shh amide-product peptides based on differences in charge and hydrodynamic radius, coupled with online fluorescence intensity measurements for quantification. The MSA format was employed to study Hhat-catalyzed reactions, investigate Hhat kinetics, and determine small-molecule inhibitor IC50 values. Both real-time and stopped assays were performed, with the latter achieved via addition of excess unlabeled Shh peptide. The MSA format therefore allows direct and real-time fluorescence-based measurement of acylation and represents a powerful alternative technique in the study of N-lipidation.
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Affiliation(s)
| | - Neki V. Patel
- Department of Chemistry, Imperial College London, London, UK
| | | | - Katherine J. Boxall
- Cancer Research UK Cancer Therapeutics Unit, The Institute of Cancer Research, London, UK
| | - Rosemary Burke
- Cancer Research UK Cancer Therapeutics Unit, The Institute of Cancer Research, London, UK
| | - Julian Blagg
- Cancer Research UK Cancer Therapeutics Unit, The Institute of Cancer Research, London, UK
| | - Anthony I. Magee
- Molecular Medicine Section, National Heart & Lung Institute, Imperial College London, London, UK
| | - Edward W. Tate
- Department of Chemistry, Imperial College London, London, UK
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21
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McGovern-Gooch KR, Mahajani NS, Garagozzo A, Schramm AJ, Hannah LG, Sieburg MA, Chisholm JD, Hougland JL. Synthetic Triterpenoid Inhibition of Human Ghrelin O-Acyltransferase: The Involvement of a Functionally Required Cysteine Provides Mechanistic Insight into Ghrelin Acylation. Biochemistry 2017; 56:919-931. [PMID: 28134508 DOI: 10.1021/acs.biochem.6b01008] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
The peptide hormone ghrelin plays a key role in regulating hunger and energy balance within the body. Ghrelin signaling presents a promising and unexploited target for development of small molecule therapeutics for treatment of obesity, diabetes, and other health conditions. Inhibition of ghrelin O-acyltransferase (GOAT), which catalyzes an essential octanoylation step in ghrelin maturation, offers a potential avenue for controlling ghrelin signaling. Through screening a small molecule library, we have identified a class of synthetic triterpenoids that efficiently inhibit ghrelin acylation by the human isoform of GOAT (hGOAT). These compounds function as covalent reversible inhibitors of hGOAT, providing the first evidence of the involvement of a nucleophilic cysteine residue in substrate acylation by a MBOAT family acyltransferase. Surprisingly, the mouse form of GOAT does not exhibit susceptibility to cysteine-modifying electrophiles, revealing an important distinction in the activity and behavior between these closely related GOAT isoforms. This study establishes these compounds as potent small molecule inhibitors of ghrelin acylation and provides a foundation for the development of novel hGOAT inhibitors as therapeutics targeting diabetes and obesity.
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Affiliation(s)
| | - Nivedita S Mahajani
- Department of Chemistry, Syracuse University , Syracuse, New York 13244, United States
| | - Ariana Garagozzo
- Department of Chemistry, Syracuse University , Syracuse, New York 13244, United States
| | - Anthony J Schramm
- Department of Chemistry, Syracuse University , Syracuse, New York 13244, United States
| | - Lauren G Hannah
- Department of Chemistry, Syracuse University , Syracuse, New York 13244, United States
| | - Michelle A Sieburg
- Department of Chemistry, Syracuse University , Syracuse, New York 13244, United States
| | - John D Chisholm
- Department of Chemistry, Syracuse University , Syracuse, New York 13244, United States
| | - James L Hougland
- Department of Chemistry, Syracuse University , Syracuse, New York 13244, United States
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22
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Approaches for the Discovery of Small Molecule Ligands Targeting microRNAs. TOPICS IN MEDICINAL CHEMISTRY 2017. [DOI: 10.1007/7355_2017_3] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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23
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McGovern-Gooch KR, Rodrigues T, Darling JE, Sieburg MA, Abizaid A, Hougland JL. Ghrelin Octanoylation Is Completely Stabilized in Biological Samples by Alkyl Fluorophosphonates. Endocrinology 2016; 157:4330-4338. [PMID: 27623288 DOI: 10.1210/en.2016-1657] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Ghrelin is a peptide hormone involved in multiple physiological processes related to energy homeostasis. This hormone features a unique posttranslational serine octanoylation modification catalyzed by the enzyme ghrelin O-acyltransferase, with serine octanoylation essential for ghrelin to bind and activate its cognate receptor. Ghrelin deacylation rapidly occurs in circulation, with both ghrelin and desacyl ghrelin playing important roles in biological signaling. Understanding the regulation and physiological impact of ghrelin signaling requires the ability to rapidly protect ghrelin from deacylation in biological samples such as blood serum or cell lysates to preserve the relative concentrations of ghrelin and desacyl ghrelin. In in vitro ghrelin O-acyltransferase activity assays using insect microsomal protein fractions and mammalian cell lysate and blood serum, we demonstrate that alkyl fluorophosphonate treatment provides rapid, complete, and long-lasting protection of ghrelin acylation against serine ester hydrolysis without interference in enzyme assay or ELISA analysis. Our results support alkyl fluorophosphonate treatment as a general tool for stabilizing ghrelin and improving measurement of ghrelin and desacyl ghrelin concentrations in biochemical and clinical investigations and suggest current estimates for active ghrelin concentration and the ghrelin to desacyl ghrelin ratio in circulation may underestimate in vivo conditions.
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Affiliation(s)
- Kayleigh R McGovern-Gooch
- Department of Chemistry (K.R.M.-G., J.E.D., M.A.S., J.L.H.), Syracuse University, Syracuse, New York 13244; and Department of Neuroscience (T.R., A.A.), Carleton University, Ottawa, Ontario, Canada K1S5B6
| | - Trevor Rodrigues
- Department of Chemistry (K.R.M.-G., J.E.D., M.A.S., J.L.H.), Syracuse University, Syracuse, New York 13244; and Department of Neuroscience (T.R., A.A.), Carleton University, Ottawa, Ontario, Canada K1S5B6
| | - Joseph E Darling
- Department of Chemistry (K.R.M.-G., J.E.D., M.A.S., J.L.H.), Syracuse University, Syracuse, New York 13244; and Department of Neuroscience (T.R., A.A.), Carleton University, Ottawa, Ontario, Canada K1S5B6
| | - Michelle A Sieburg
- Department of Chemistry (K.R.M.-G., J.E.D., M.A.S., J.L.H.), Syracuse University, Syracuse, New York 13244; and Department of Neuroscience (T.R., A.A.), Carleton University, Ottawa, Ontario, Canada K1S5B6
| | - Alfonso Abizaid
- Department of Chemistry (K.R.M.-G., J.E.D., M.A.S., J.L.H.), Syracuse University, Syracuse, New York 13244; and Department of Neuroscience (T.R., A.A.), Carleton University, Ottawa, Ontario, Canada K1S5B6
| | - James L Hougland
- Department of Chemistry (K.R.M.-G., J.E.D., M.A.S., J.L.H.), Syracuse University, Syracuse, New York 13244; and Department of Neuroscience (T.R., A.A.), Carleton University, Ottawa, Ontario, Canada K1S5B6
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24
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Lorenz DA, Garner AL. A click chemistry-based microRNA maturation assay optimized for high-throughput screening. Chem Commun (Camb) 2016; 52:8267-70. [PMID: 27284591 DOI: 10.1039/c6cc02894b] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Catalytic enzyme-linked click-chemistry assays (cat-ELCCA) are an emerging class of biochemical assay. Herein we report on expanding the toolkit of cat-ELCCA to include the kinetically superior inverse-electron demand Diels-Alder (IEDDA) reaction. The result is a technology with improved sensitivity and reproducibility, enabling automated high-throughput screening.
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Affiliation(s)
- Daniel A Lorenz
- Program in Chemical Biology, University of Michigan, 210 Washtenaw Avenue, Ann Arbor, Michigan 48109, USA
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25
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Bando M, Iwakura H, Koyama H, Hosoda H, Shigematsu Y, Ariyasu H, Akamizu T, Kangawa K, Nakao K. High incorporation of long-chain fatty acids contributes to the efficient production of acylated ghrelin in ghrelin-producing cells. FEBS Lett 2016; 590:992-1001. [PMID: 26991015 DOI: 10.1002/1873-3468.12132] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2015] [Revised: 03/08/2016] [Accepted: 03/08/2016] [Indexed: 02/03/2023]
Abstract
The mechanisms for supplying octanoic acid for ghrelin acylation in X/A-like cells are incompletely understood. We found that long-chain fatty acids were incorporated at a higher rate in the ghrelin-producing cell line MGN3-1 than in MIN6 cells, in part due to higher expression level of long-chain fatty acyl-CoA synthetase family member 1 (Acsl1). Inhibition of ACSLs by triacsin C profoundly suppressed acylated ghrelin production. These results suggest that high incorporation of long-chain fatty acids into the ghrelin-producing cells plays a role in the supply of octanoic acid for ghrelin acylation.
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Affiliation(s)
- Mika Bando
- Medical Innovation Center, Kyoto University Graduate School of Medicine, Japan
| | - Hiroshi Iwakura
- Medical Innovation Center, Kyoto University Graduate School of Medicine, Japan
| | - Hiroyuki Koyama
- Department of Diabetes, Endocrinology and Nutrition, Kyoto University Graduate School of Medicine, Japan
| | - Hiroshi Hosoda
- National Cerebral and Cardiovascular Center Research Institute, Osaka, Japan
| | - Yosuke Shigematsu
- Department of Health Science, Faculty of Medical Sciences, University of Fukui, Japan
| | - Hiroyuki Ariyasu
- The First Department of Medicine, Wakayama Medical University, Japan
| | - Takashi Akamizu
- The First Department of Medicine, Wakayama Medical University, Japan
| | - Kenji Kangawa
- Medical Innovation Center, Kyoto University Graduate School of Medicine, Japan.,National Cerebral and Cardiovascular Center Research Institute, Osaka, Japan
| | - Kazuwa Nakao
- Medical Innovation Center, Kyoto University Graduate School of Medicine, Japan
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26
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27
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Lanyon-Hogg T, Masumoto N, Bodakh G, Konitsiotis AD, Thinon E, Rodgers UR, Owens RJ, Magee AI, Tate EW. Click chemistry armed enzyme-linked immunosorbent assay to measure palmitoylation by hedgehog acyltransferase. Anal Biochem 2015; 490:66-72. [PMID: 26334609 PMCID: PMC4615133 DOI: 10.1016/j.ab.2015.08.025] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2015] [Revised: 08/20/2015] [Accepted: 08/21/2015] [Indexed: 12/30/2022]
Abstract
Hedgehog signaling is critical for correct embryogenesis and tissue development. However, on maturation, signaling is also found to be aberrantly activated in many cancers. Palmitoylation of the secreted signaling protein sonic hedgehog (Shh) by the enzyme hedgehog acyltransferase (Hhat) is required for functional signaling. To quantify this important posttranslational modification, many in vitro Shh palmitoylation assays employ radiolabeled fatty acids, which have limitations in terms of cost and safety. Here we present a click chemistry armed enzyme-linked immunosorbent assay (click-ELISA) for assessment of Hhat activity through acylation of biotinylated Shh peptide with an alkyne-tagged palmitoyl-CoA (coenzyme A) analogue. Click chemistry functionalization of the alkyne tag with azido-FLAG peptide allows analysis through an ELISA protocol and colorimetric readout. This assay format identified the detergent n-dodecyl β-d-maltopyranoside as an improved solubilizing agent for Hhat activity. Quantification of the potency of RU-SKI small molecule Hhat inhibitors by click-ELISA indicated IC50 values in the low- or sub-micromolar range. A stopped assay format was also employed that allows measurement of Hhat kinetic parameters where saturating substrate concentrations exceed the binding capacity of the streptavidin-coated plate. Therefore, click-ELISA represents a nonradioactive method for assessing protein palmitoylation in vitro that is readily expandable to other classes of protein lipidation.
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Affiliation(s)
- Thomas Lanyon-Hogg
- Institute of Chemical Biology, Department of Chemistry, Imperial College London, South Kensington SW7 2AZ, UK
| | - Naoko Masumoto
- Institute of Chemical Biology, Department of Chemistry, Imperial College London, South Kensington SW7 2AZ, UK
| | - George Bodakh
- Institute of Chemical Biology, Department of Chemistry, Imperial College London, South Kensington SW7 2AZ, UK
| | - Antonio D Konitsiotis
- Molecular Medicine Section, National Heart & Lung Institute, Imperial College London, South Kensington SW7 2AZ, UK
| | - Emmanuelle Thinon
- Institute of Chemical Biology, Department of Chemistry, Imperial College London, South Kensington SW7 2AZ, UK
| | - Ursula R Rodgers
- Molecular Medicine Section, National Heart & Lung Institute, Imperial College London, South Kensington SW7 2AZ, UK
| | - Raymond J Owens
- Division of Structural Biology, Henry Wellcome Building for Genomic Medicine, University of Oxford, Roosevelt Drive, Oxford, OX3 7BN, UK; OPPF-UK, The Research Complex at Harwell, Rutherford Appleton Laboratory, Harwell, Oxfordshire, OX11 0FA, UK
| | - Anthony I Magee
- Molecular Medicine Section, National Heart & Lung Institute, Imperial College London, South Kensington SW7 2AZ, UK.
| | - Edward W Tate
- Institute of Chemical Biology, Department of Chemistry, Imperial College London, South Kensington SW7 2AZ, UK.
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28
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Taylor MS, Dempsey DR, Hwang Y, Chen Z, Chu N, Boeke JD, Cole PA. Mechanistic analysis of ghrelin-O-acyltransferase using substrate analogs. Bioorg Chem 2015; 62:64-73. [PMID: 26246082 DOI: 10.1016/j.bioorg.2015.07.003] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2015] [Revised: 07/10/2015] [Accepted: 07/13/2015] [Indexed: 11/15/2022]
Abstract
Ghrelin-O-Acyltransferase (GOAT) is an 11-transmembrane integral membrane protein that octanoylates the metabolism-regulating peptide hormone ghrelin at Ser3 and may represent an attractive target for the treatment of type II diabetes and the metabolic syndrome. Protein octanoylation is unique to ghrelin in humans, and little is known about the mechanism of GOAT or of related protein-O-acyltransferases HHAT or PORC. In this study, we explored an in vitro microsomal ghrelin octanoylation assay to analyze its enzymologic features. Measurement of Km for 10-mer, 27-mer, and synthetic Tat-peptide-containing ghrelin substrates provided evidence for a role of charge interactions in substrate binding. Ghrelin substrates with amino-alanine in place of Ser3 demonstrated that GOAT can catalyze the formation of an octanoyl-amide bond at a similar rate compared with the natural reaction. A pH-rate comparison of these substrates revealed minimal differences in acyltransferase activity across pH 6.0-9.0, providing evidence that these reactions may be relatively insensitive to the basicity of the substrate nucleophile. The conserved His338 residue was required both for Ser3 and amino-Ala3 ghrelin substrates, suggesting that His338 may have a key catalytic role beyond that of a general base.
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Affiliation(s)
- Martin S Taylor
- Department of Pharmacology & Molecular Sciences, The Johns Hopkins University School of Medicine, Baltimore, MD, USA; Department of Molecular Biology & Genetics and High Throughput Biology Center, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Daniel R Dempsey
- Department of Pharmacology & Molecular Sciences, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Yousang Hwang
- Department of Pharmacology & Molecular Sciences, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Zan Chen
- Department of Pharmacology & Molecular Sciences, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Nam Chu
- Department of Pharmacology & Molecular Sciences, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Jef D Boeke
- Department of Molecular Biology & Genetics and High Throughput Biology Center, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Philip A Cole
- Department of Pharmacology & Molecular Sciences, The Johns Hopkins University School of Medicine, Baltimore, MD, USA.
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29
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A new class of ghrelin O-acyltransferase inhibitors incorporating triazole-linked lipid mimetic groups. Bioorg Med Chem Lett 2015; 25:2800-3. [PMID: 26009163 DOI: 10.1016/j.bmcl.2015.05.009] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2015] [Revised: 05/04/2015] [Accepted: 05/06/2015] [Indexed: 02/06/2023]
Abstract
Inhibitors of ghrelin O-acyltransferase (GOAT) have untapped potential as therapeutics targeting obesity and diabetes. We report the first examples of GOAT inhibitors incorporating a triazole linkage as a biostable isosteric replacement for the ester bond in ghrelin and amide bonds in previously reported GOAT inhibitors. These triazole-containing inhibitors exhibit sub-micromolar inhibition of the human isoform of GOAT (hGOAT), and provide a foundation for rapid future chemical diversification and optimization of hGOAT inhibitors.
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30
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Masumoto N, Lanyon-Hogg T, Rodgers UR, Konitsiotis AD, Magee AI, Tate EW. Membrane bound O-acyltransferases and their inhibitors. Biochem Soc Trans 2015; 43:246-52. [PMID: 25849925 DOI: 10.1042/bst20150018] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Since the identification of the membrane-bound O-acyltransferase (MBOATs) protein family in the early 2000s, three distinct members [porcupine (PORCN), hedgehog (Hh) acyltransferase (HHAT) and ghrelin O-acyltransferase (GOAT)] have been shown to acylate specific proteins or peptides. In this review, topology determination, development of assays to measure enzymatic activities and discovery of small molecule inhibitors are compared and discussed for each of these enzymes.
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Affiliation(s)
- Naoko Masumoto
- *Department of Chemistry, Imperial College London, South Kensington Campus, London, SW7 2AZ, U.K
| | - Thomas Lanyon-Hogg
- *Department of Chemistry, Imperial College London, South Kensington Campus, London, SW7 2AZ, U.K
| | - Ursula R Rodgers
- ‡Molecular Medicine Section, National Lung & Heart Institute, Sir Alexander Fleming Building, South Kensington Campus, Imperial College London, SW7 2AZ, U.K
| | - Antonios D Konitsiotis
- ‡Molecular Medicine Section, National Lung & Heart Institute, Sir Alexander Fleming Building, South Kensington Campus, Imperial College London, SW7 2AZ, U.K
| | - Anthony I Magee
- †Institute of Chemical Biology, Department of Chemistry, Imperial College London, SW7 2AZ, U.K
| | - Edward W Tate
- *Department of Chemistry, Imperial College London, South Kensington Campus, London, SW7 2AZ, U.K
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31
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Lorenz DA, Song JM, Garner AL. High-throughput platform assay technology for the discovery of pre-microrna-selective small molecule probes. Bioconjug Chem 2015; 26:19-23. [PMID: 25506628 DOI: 10.1021/bc500544v] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
MicroRNAs (miRNA) play critical roles in human development and disease. As such, the targeting of miRNAs is considered attractive as a novel therapeutic strategy. A major bottleneck toward this goal, however, has been the identification of small molecule probes that are specific for select RNAs and methods that will facilitate such discovery efforts. Using pre-microRNAs as proof-of-concept, herein we report a conceptually new and innovative approach for assaying RNA-small molecule interactions. Through this platform assay technology, which we term catalytic enzyme-linked click chemistry assay or cat-ELCCA, we have designed a method that can be implemented in high throughput, is virtually free of false readouts, and is general for all nucleic acids. Through cat-ELCCA, we envision the discovery of selective small molecule ligands for disease-relevant miRNAs to promote the field of RNA-targeted drug discovery and further our understanding of the role of miRNAs in cellular biology.
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Affiliation(s)
- Daniel A Lorenz
- Program in Chemical Biology and ‡Department of Medicinal Chemistry, College of Pharmacy, University of Michigan , Ann Arbor, Michigan 48109, United States
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32
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Darling JE, Zhao F, Loftus RJ, Patton LM, Gibbs RA, Hougland JL. Structure–Activity Analysis of Human Ghrelin O-Acyltransferase Reveals Chemical Determinants of Ghrelin Selectivity and Acyl Group Recognition. Biochemistry 2015; 54:1100-10. [DOI: 10.1021/bi5010359] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Joseph E. Darling
- Department
of Chemistry, Syracuse University, Syracuse, New York 13244, United States
| | - Feifei Zhao
- Department
of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, West Lafayette, Indiana 47907, United States
| | - Rosemary J. Loftus
- Department
of Chemistry, Syracuse University, Syracuse, New York 13244, United States
| | - Leslie M. Patton
- Department
of Chemistry, Syracuse University, Syracuse, New York 13244, United States
| | - Richard A. Gibbs
- Department
of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, West Lafayette, Indiana 47907, United States
| | - James L. Hougland
- Department
of Chemistry, Syracuse University, Syracuse, New York 13244, United States
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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: 0.9] [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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Xie L, Zheng H, Ye W, Qiu S, Lin Z, Guo L, Qiu B, Chen G. Novel colorimetric molecular switch based on copper(I)-catalyzed azide-alkyne cycloaddition reaction and its application for flumioxazin detection. Analyst 2014. [PMID: 23188065 DOI: 10.1039/c2an36023c] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
A novel colorimetric switch based on the copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC) reaction has been developed. G-quadruplex-hemin DNAzyme catalyzes the oxidation of 2,2'-azinobis(3-ethylbenzothiozoline)-6-sulfonic acid (ABTS) to form ABTS˙(+), the UV absorbance of the solution increased greatly and the color of the solution changed to dark green. However, in the presence of an azide complex, the absorbance signal decreased and the solution became light green since the catalytic ability of the hemin was inhibited by the azide groups. However, once propargylamine has been added into the above reaction system, which would react with azide groups through the CuAAC reaction, the solution becomes dark green again and the absorption intensity of the system is also increased. The proposed switch allows a good reversibility and can be identified clearly by the naked eye. In addition, the method has been applied to detect some pesticides, which have alkynyl groups (flumioxazin), with high sensitivity and selectivity, where the UV absorbance has a direct linear relationship with the logarithm of flumioxazin concentrations in the range of 0.14-14 nM, and the limit of detection was 0.056 nM (S/N = 3), which can meet the requirement of the maximum residue limits (MRLs) of United States of America (56 nM).
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Affiliation(s)
- Lidan Xie
- Ministry of Education Key Laboratory of Analysis and Detection for Food Safety, Fuzhou University, Fuzhou, Fujian 350002, China
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35
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A fluorescent peptide substrate facilitates investigation of ghrelin recognition and acylation by ghrelin O-acyltransferase. Anal Biochem 2013; 437:68-76. [DOI: 10.1016/j.ab.2013.02.013] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2012] [Revised: 02/12/2013] [Accepted: 02/16/2013] [Indexed: 01/24/2023]
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36
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Goebel-Stengel M, Hofmann T, Elbelt U, Teuffel P, Ahnis A, Kobelt P, Lambrecht NWG, Klapp BF, Stengel A. The ghrelin activating enzyme ghrelin-O-acyltransferase (GOAT) is present in human plasma and expressed dependent on body mass index. Peptides 2013; 43:13-9. [PMID: 23454172 DOI: 10.1016/j.peptides.2013.02.011] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/02/2013] [Revised: 02/13/2013] [Accepted: 02/18/2013] [Indexed: 01/16/2023]
Abstract
Ghrelin is the only known peripherally produced and centrally acting peptide hormone stimulating food intake. The acylation of ghrelin is essential for binding to its receptor. Recently, the ghrelin activating enzyme ghrelin-O-acyltransferase (GOAT) was identified in mice, rats and humans. In addition to gastric mucosal expression, GOAT was also detected in the circulation of rodents and its expression was dependent on metabolic status. We investigated whether GOAT is also present in human plasma and whether expression levels are affected under different conditions of body weight. Normal weight, anorexic and obese subjects with body mass index (BMI) 30-40, 40-50 and >50 were recruited (n=9/group). In overnight fasted subjects GOAT protein expression was assessed by Western blot and ghrelin measured by ELISA. GOAT protein was detectable in human plasma. Anorexic patients showed reduced GOAT protein levels (-42%, p<0.01) whereas obese patients with BMI>50 had increased concentrations (+34%) compared to normal weight controls. Ghrelin levels were higher in anorexic patients compared to all other groups (+62-78%, p<0.001). Plasma GOAT protein expression showed a positive correlation with BMI (r=0.71, p<0.001) and a negative correlation with ghrelin (r=-0.60, p<0.001). Summarized, GOAT is also present in human plasma and GOAT protein levels depend on the metabolic environment with decreased levels in anorexic and increased levels in morbidly obese patients. These data may indicate that GOAT counteracts the adaptive changes of ghrelin observed under these conditions and ultimately contributes to the development or maintenance of anorexia and obesity as it is the only enzyme acylating ghrelin.
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Affiliation(s)
- Miriam Goebel-Stengel
- Department of Internal Medicine, Institute of Neurogastroenterology and Motility, Martin-Luther Hospital, Academic Teaching Institution of Charité-Universitätsmedizin Berlin, Berlin, Germany
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37
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Qiu S, Miao M, Wang T, Lin Z, Guo L, Qiu B, Chen G. A fluorescent probe for detection of histidine in cellular homogenate and ovalbumin based on the strategy of clickchemistry. Biosens Bioelectron 2013. [DOI: 10.1016/j.bios.2012.10.039] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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38
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A novel fluorescent sensor for mutational p53 DNA sequence detection based on click chemistry. Biosens Bioelectron 2013; 41:403-8. [DOI: 10.1016/j.bios.2012.08.065] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2012] [Accepted: 08/31/2012] [Indexed: 11/22/2022]
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39
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Abstract
Ghrelin O-acyltransferase (GOAT) is responsible for catalyzing the attachment of the eight-carbon fatty acid octanoyl to the Ser3 side chain of the peptide ghrelin to generate the active form of this metabolic hormone. As such, GOAT is viewed as a potential therapeutic target for the treatment of obesity and diabetes mellitus. Here, we review recent progress in the development of cell and in vitro assays to measure GOAT action and the identification of several synthetic GOAT inhibitors. In particular, we discuss the design, synthesis, and characterization of the bisubstrate analog GO-CoA-Tat and its ability to modulate weight and blood glucose in mice. We also highlight current challenges and future research directions in our biomedical understanding of this fascinating ghrelin processing enzyme.
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Affiliation(s)
- Martin S Taylor
- Department of Pharmacology & Molecular Sciences, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
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40
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Stengel A, Wang L, Taché Y. Stress-related alterations of acyl and desacyl ghrelin circulating levels: mechanisms and functional implications. Peptides 2011; 32:2208-17. [PMID: 21782868 PMCID: PMC3220774 DOI: 10.1016/j.peptides.2011.07.002] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/20/2011] [Revised: 07/04/2011] [Accepted: 07/05/2011] [Indexed: 12/11/2022]
Abstract
Ghrelin is the only known peripherally produced and centrally acting peptide hormone that stimulates food intake and digestive functions. Ghrelin circulates as acylated and desacylated forms and recently the acylating enzyme, ghrelin-O-acyltransferase (GOAT) and the de-acylating enzyme, thioesterase 1/lysophospholipase 1 have been identified adding new layers of complexity to the regulation of ghrelin. Stress is known to alter gastrointestinal motility and food intake and was recently shown to modify circulating ghrelin and GOAT levels with differential responses related to the type of stressors including a reduction induced by physical stressors (abdominal surgery and immunological/endotoxin injection, exercise) and elevation by metabolic (cold exposure, acute fasting and caloric restriction) and psychological stressors. However, the pathways underlying the alterations of ghrelin under these various stress conditions are still largely to be defined and may relate to stress-associated autonomic changes. There is evidence that alterations of circulating ghrelin may contribute to the neuroendocrine and behavioral responses along with sustaining the energetic requirement needed upon repeated exposure to stressors. A better understanding of these mechanisms will allow targeting components of ghrelin signaling that may improve food intake and gastric motility alterations induced by stress.
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Affiliation(s)
- Andreas Stengel
- CURE: Digestive Diseases Research Center, David Geffen School of Medicine, University of California Los Angeles and Veterans Affairs Greater Los Angeles Healthcare System, Los Angeles, CA 90073, United States.
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41
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Stengel A, Goebel-Stengel M, Wang L, Shaikh A, Lambrecht NWG, Rivier J, Taché Y. Abdominal surgery inhibits circulating acyl ghrelin and ghrelin-O-acyltransferase levels in rats: role of the somatostatin receptor subtype 2. Am J Physiol Gastrointest Liver Physiol 2011; 301:G239-48. [PMID: 21636529 PMCID: PMC3154605 DOI: 10.1152/ajpgi.00018.2011] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Clinical studies are evaluating the efficacy of synthetic ghrelin agonists in postoperative ileus management. However, the control of ghrelin secretion under conditions of postoperative gastric ileus is largely unknown. Peripheral somatostatin inhibits ghrelin secretion in animals and humans. We investigated the time course of ghrelin changes postsurgery in fasted rats and whether somatostatin receptor subtype 2 (sst(2)) signaling is involved. Abdominal surgery (laparotomy and 1-min cecal palpation) induced a rapid and long-lasting decrease in plasma acyl ghrelin levels as shown by the 64, 67, and 59% reduction at 0.5, 2, and 5 h postsurgery, respectively, compared with sham (anesthesia alone for 10 min, P < 0.05). Levels were partly recovered at 7 h and fully restored at 24 h. The percentage of acyl ghrelin reduction was significantly higher than that of desacyl ghrelin at 2 h postsurgery and not at any other time point. This was associated with a 48 and 23% decrease in gastric and plasma ghrelin-O-acyltransferase protein concentrations, respectively (P < 0.001). Ghrelin-positive cells in the oxyntic mucosa expressed sst(2a) receptor and the sst(2) agonist S-346-011 inhibited fasting acyl ghrelin levels by 64 and 77% at 0.5 and 2 h, respectively. The sst(2) antagonist S-406-028 prevented the abdominal surgery-induced decreased circulating acyl ghrelin but not the delayed gastric emptying assessed 0.5 h postinjection. These data show that activation of sst(2) receptor located on gastric X/A-like cells plays a key role in the rapid inhibition of circulating acyl ghrelin induced by abdominal surgery while not being primarily involved in the early phase of postoperative gastric ileus.
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Affiliation(s)
- Andreas Stengel
- 1Department of Medicine, CURE Digestive Diseases Research Center, Center for Neurobiology of Stress, Digestive Diseases Division at University of California Los Angeles and Veterans Affairs Greater Los Angeles Healthcare System, Los Angeles;
| | - Miriam Goebel-Stengel
- 1Department of Medicine, CURE Digestive Diseases Research Center, Center for Neurobiology of Stress, Digestive Diseases Division at University of California Los Angeles and Veterans Affairs Greater Los Angeles Healthcare System, Los Angeles;
| | - Lixin Wang
- 1Department of Medicine, CURE Digestive Diseases Research Center, Center for Neurobiology of Stress, Digestive Diseases Division at University of California Los Angeles and Veterans Affairs Greater Los Angeles Healthcare System, Los Angeles;
| | - Almaas Shaikh
- 1Department of Medicine, CURE Digestive Diseases Research Center, Center for Neurobiology of Stress, Digestive Diseases Division at University of California Los Angeles and Veterans Affairs Greater Los Angeles Healthcare System, Los Angeles;
| | - Nils W. G. Lambrecht
- 2Gastrointestinal Endocrinology, Veterans Affairs Long Beach Healthcare System, Long Beach; and
| | - Jean Rivier
- 3Peptide Biology Laboratories, Salk Institute, La Jolla, California
| | - Yvette Taché
- 1Department of Medicine, CURE Digestive Diseases Research Center, Center for Neurobiology of Stress, Digestive Diseases Division at University of California Los Angeles and Veterans Affairs Greater Los Angeles Healthcare System, Los Angeles;
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42
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Ran Q, Peng R, Liang C, Ye S, Xian Y, Zhang W, Jin L. Direct electrochemistry of horseradish peroxidase immobilized on electrografted 4-ethynylphenyl film via click chemistry. Anal Chim Acta 2011; 697:27-31. [DOI: 10.1016/j.aca.2011.04.035] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2011] [Revised: 04/13/2011] [Accepted: 04/18/2011] [Indexed: 11/29/2022]
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43
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Garner AL, Janda KD. A small molecule antagonist of ghrelin O-acyltransferase (GOAT). Chem Commun (Camb) 2011; 47:7512-4. [PMID: 21594284 DOI: 10.1039/c1cc11817j] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Using our recently disclosed fluorescence-based assay to monitor acyltransferase activity, the first non-peptidic, small molecule antagonists of ghrelin O-acyltransferase (GOAT), a potential anti-obesity and anti-diabetes target, have been discovered. Each exhibits micromolar inhibition of the enzyme, and may be useful probes for future study of the ghrelin-GOAT system.
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Affiliation(s)
- Amanda L Garner
- Department of Chemistry, The Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
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44
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Garner AL, Janda KD. Shedding Light on the Ghrelin/GOAT Metabolism Saga. Chembiochem 2011; 12:523-5. [DOI: 10.1002/cbic.201000777] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2010] [Indexed: 12/22/2022]
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