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Nwamba OC. Membranes as the third genetic code. Mol Biol Rep 2020; 47:4093-4097. [PMID: 32279211 DOI: 10.1007/s11033-020-05437-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Accepted: 04/03/2020] [Indexed: 02/07/2023]
Abstract
Biological membranes and their compositions influence cellular function, age and disease states of organisms. They achieve this by effecting the outcome of bound enzymes/proteins and carbohydrate moieties. While the membrane-bound carbohydrates give rise to antigenicity, membranes impact the eventual outcome of protein structures that would function even outside their enclosure. This is achieved by membrane modulation of translational and post-translational protein folding. Thus, the eventual 3D structures and functions of proteins might not be solely dependent on their primary amino acid sequences and surrounding environments. The 3D protein structures would also depend on enclosing membrane properties such as fluidity, other intrinsic and extrinsic proteins and carbohydrate functionalities. Also, membranes moderate DNA activities with consequences on gene activation-inactivation mechanisms. Consequently, membranes are almost indispensable to the functioning of other cell compositions and serve to modulate these other components. Besides, membrane lipid compositions are also moderated by nutrition and diets and the converse is true. Thus, it could be argued that membranes are the third genetic codes. Suggestively, membranes are at the center of the interplay between nature and nurture in health and disease states.
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Mocking TAM, Buzink MCML, Leurs R, Vischer HF. Bioluminescence Resonance Energy Transfer Based G Protein-Activation Assay to Probe Duration of Antagonism at the Histamine H 3 Receptor. Int J Mol Sci 2019; 20:ijms20153724. [PMID: 31366084 PMCID: PMC6695674 DOI: 10.3390/ijms20153724] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2019] [Revised: 07/27/2019] [Accepted: 07/28/2019] [Indexed: 12/30/2022] Open
Abstract
Duration of receptor antagonism, measured as the recovery of agonist responsiveness, is gaining attention as a method to evaluate the 'effective' target-residence for antagonists. These functional assays might be a good alternative for kinetic binding assays in competition with radiolabeled or fluorescent ligands, as they are performed on intact cells and better reflect consequences of dynamic cellular processes on duration of receptor antagonism. Here, we used a bioluminescence resonance energy transfer (BRET)-based assay that monitors heterotrimeric G protein activation via scavenging of released Venus-Gβ1γ2 by NanoLuc (Nluc)-tagged membrane-associated-C-terminal fragment of G protein-coupled receptor kinase 3 (masGRK3ct-Nluc) as a tool to probe duration of G protein-coupled receptor (GPCR) antagonism. The Gαi-coupled histamine H3 receptor (H3R) was used in this study as prolonged antagonism is associated with adverse events (e.g., insomnia) and consequently, short-residence time ligands might be preferred. Due to its fast and prolonged response, this assay can be used to determine the duration of functional antagonism by measuring the recovery of agonist responsiveness upon washout of pre-bound antagonist, and to assess antagonist re-equilibration time via Schild-plot analysis. Re-equilibration of pre-incubated antagonist with agonist and receptor could be followed in time to monitor the transition from insurmountable to surmountable antagonism. The BRET-based G protein activation assay can detect differences in the recovery of H3R responsiveness and re-equilibration of pre-bound antagonists between the tested H3R antagonists. Fast dissociation kinetics were observed for marketed drug pitolisant (Wakix®) in this assay, which suggests that short residence time might be beneficial for therapeutic targeting of the H3R.
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Affiliation(s)
- Tamara A M Mocking
- Amsterdam Institute for Molecules, Medicines and Systems (AIMMS), Division of Medicinal Chemistry, Faculty of Science, Vrije Universiteit Amsterdam, De Boelelaan 1108, 1081 HZ Amsterdam, The Netherlands
| | - Maurice C M L Buzink
- Amsterdam Institute for Molecules, Medicines and Systems (AIMMS), Division of Medicinal Chemistry, Faculty of Science, Vrije Universiteit Amsterdam, De Boelelaan 1108, 1081 HZ Amsterdam, The Netherlands
| | - Rob Leurs
- Amsterdam Institute for Molecules, Medicines and Systems (AIMMS), Division of Medicinal Chemistry, Faculty of Science, Vrije Universiteit Amsterdam, De Boelelaan 1108, 1081 HZ Amsterdam, The Netherlands
| | - Henry F Vischer
- Amsterdam Institute for Molecules, Medicines and Systems (AIMMS), Division of Medicinal Chemistry, Faculty of Science, Vrije Universiteit Amsterdam, De Boelelaan 1108, 1081 HZ Amsterdam, The Netherlands.
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A live cell NanoBRET binding assay allows the study of ligand-binding kinetics to the adenosine A 3 receptor. Purinergic Signal 2019; 15:139-153. [PMID: 30919204 PMCID: PMC6635573 DOI: 10.1007/s11302-019-09650-9] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2018] [Accepted: 02/14/2019] [Indexed: 01/14/2023] Open
Abstract
There is a growing interest in understanding the binding kinetics of compounds that bind to G protein-coupled receptors prior to progressing a lead compound into clinical trials. The widely expressed adenosine A3 receptor (A3AR) has been implicated in a range of diseases including immune conditions, and compounds that aim to selectively target this receptor are currently under development for arthritis. Kinetic studies at the A3AR have been performed using a radiolabelled antagonist, but due to the kinetics of this probe, they have been carried out at 10 °C in membrane preparations. In this study, we have developed a live cell NanoBRET ligand binding assay using fluorescent A3AR antagonists to measure kinetic parameters of labelled and unlabelled compounds at the A3AR at physiological temperatures. The kinetic profiles of four fluorescent antagonists were determined in kinetic association assays, and it was found that XAC-ser-tyr-X-BY630 had the longest residence time (RT = 288 ± 62 min) at the A3AR. The association and dissociation rate constants of three antagonists PSB-11, compound 5, and LUF7565 were also determined using two fluorescent ligands (XAC-ser-tyr-X-BY630 or AV039, RT = 6.8 ± 0.8 min) as the labelled probe and compared to those obtained using a radiolabelled antagonist ([3H]PSB-11, RT = 44.6 ± 3.9 min). There was close agreement in the kinetic parameters measured with AV039 and [3H]PSB-11 but significant differences to those obtained using XAC-S-ser-S-tyr-X-BY630. These data indicate that selecting a probe with the appropriate kinetics is important to accurately determine the kinetics of unlabelled ligands with markedly different kinetic profiles.
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White CW, Johnstone EKM, See HB, Pfleger KDG. NanoBRET ligand binding at a GPCR under endogenous promotion facilitated by CRISPR/Cas9 genome editing. Cell Signal 2018; 54:27-34. [PMID: 30471466 DOI: 10.1016/j.cellsig.2018.11.018] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2018] [Revised: 11/10/2018] [Accepted: 11/20/2018] [Indexed: 01/14/2023]
Abstract
Bioluminescence resonance energy transfer (BRET) is a versatile tool used to investigate membrane receptor signalling and function. We have recently developed a homogenous NanoBRET ligand binding assay to monitor interactions between G protein-coupled receptors and fluorescent ligands. However, this assay requires the exogenous expression of a receptor fused to the nanoluciferase (Nluc) and is thus not applicable to natively-expressed receptors. To overcome this limitation in HEK293 cells, we have utilised CRISPR/Cas9 genome engineering to insert Nluc in-frame with the endogenous ADORA2B locus this resulted in HEK293 cells expressing adenosine A2B receptors under endogenous promotion tagged on their N-terminus with Nluc. As expected, we found relatively low levels of endogenous (gene-edited) Nluc/A2B receptor expression compared to cells transiently transfected with expression vectors coding for Nluc/A2B. However, in cells expressing gene-edited Nluc/A2B receptors we observed clear saturable ligand binding of a non-specific fluorescent adenosine receptor antagonist XAC-X-BY630 (Kd = 21.4 nM). Additionally, at gene-edited Nluc/A2B receptors we derived pharmacological parameters of ligand binding; Kd as well as Kon and Koff for binding of XAC-X-BY630 by NanoBRET association kinetic binding assays. Lastly, cells expressing gene-edited Nluc/A2B were used to determine the pKi of unlabelled adenosine receptor ligands in competition ligand binding assays. Utilising CRISPR/Cas9 genome engineering here we show that NanoBRET ligand binding assays can be performed at gene-edited receptors under endogenous promotion in live cells, therefore overcoming a fundamental limitation of NanoBRET ligand assays.
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Affiliation(s)
- Carl W White
- Molecular Endocrinology and Pharmacology, Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands, Western Australia 6009, Australia; Centre for Medical Research, The University of Western Australia, Crawley, Western Australia 6009, Australia; Australian Research Council Centre for Personalised Therapeutics Technologies, Australia.
| | - Elizabeth K M Johnstone
- Molecular Endocrinology and Pharmacology, Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands, Western Australia 6009, Australia; Centre for Medical Research, The University of Western Australia, Crawley, Western Australia 6009, Australia; Australian Research Council Centre for Personalised Therapeutics Technologies, Australia
| | - Heng B See
- Molecular Endocrinology and Pharmacology, Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands, Western Australia 6009, Australia; Centre for Medical Research, The University of Western Australia, Crawley, Western Australia 6009, Australia; Australian Research Council Centre for Personalised Therapeutics Technologies, Australia
| | - Kevin D G Pfleger
- Molecular Endocrinology and Pharmacology, Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands, Western Australia 6009, Australia; Centre for Medical Research, The University of Western Australia, Crawley, Western Australia 6009, Australia; Australian Research Council Centre for Personalised Therapeutics Technologies, Australia; Dimerix Limited, Nedlands, Western Australia 6009, Australia.
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Mocking TAM, Verweij EWE, Vischer HF, Leurs R. Homogeneous, Real-Time NanoBRET Binding Assays for the Histamine H 3 and H 4 Receptors on Living Cells. Mol Pharmacol 2018; 94:1371-1381. [PMID: 30249614 DOI: 10.1124/mol.118.113373] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2018] [Accepted: 09/19/2018] [Indexed: 11/22/2022] Open
Abstract
Receptor-binding affinity and ligand-receptor residence time are key parameters for the selection of drug candidates and are routinely determined using radioligand competition-binding assays. Recently, a novel bioluminescence resonance energy transfer (BRET) method utilizing a NanoLuc-fused receptor was introduced to detect fluorescent ligand binding. Moreover, this NanoBRET method gives the opportunity to follow fluorescent ligand binding on intact cells in real time, and therefore, results might better reflect in vivo conditions as compared with the routinely used cell homogenates or purified membrane fractions. In this study, a real-time NanoBRET-based binding assay was established and validated to detect binding of unlabeled ligands to the histamine H3 receptor (H3R) and histamine H4 receptor on intact cells. Obtained residence times of clinically tested H3R antagonists were reflected by their duration of H3R antagonism in a functional receptor recovery assay.
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Affiliation(s)
- Tamara A M Mocking
- Amsterdam Institute for Molecules, Medicines and Systems, Division of Medicinal Chemistry, Faculty of Science, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Eléonore W E Verweij
- Amsterdam Institute for Molecules, Medicines and Systems, Division of Medicinal Chemistry, Faculty of Science, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Henry F Vischer
- Amsterdam Institute for Molecules, Medicines and Systems, Division of Medicinal Chemistry, Faculty of Science, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Rob Leurs
- Amsterdam Institute for Molecules, Medicines and Systems, Division of Medicinal Chemistry, Faculty of Science, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
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Stoddart LA, Kilpatrick LE, Hill SJ. NanoBRET Approaches to Study Ligand Binding to GPCRs and RTKs. Trends Pharmacol Sci 2018; 39:136-147. [PMID: 29132917 DOI: 10.1016/j.tips.2017.10.006] [Citation(s) in RCA: 71] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2017] [Revised: 10/12/2017] [Accepted: 10/17/2017] [Indexed: 12/30/2022]
Abstract
Recent advances in the development of fluorescent ligands for G-protein-coupled receptors (GPCRs) and receptor tyrosine kinase receptors (RTKs) have facilitated the study of these receptors in living cells. A limitation of these ligands is potential uptake into cells and increased nonspecific binding. However, this can largely be overcome by using proximity approaches, such as bioluminescence resonance energy transfer (BRET), which localise the signal (within 10nm) to the specific receptor target. The recent engineering of NanoLuc has resulted in a luciferase variant that is smaller and significantly brighter (up to tenfold) than existing variants. Here, we review the use of BRET from N-terminal NanoLuc-tagged GPCRs or a RTK to a receptor-bound fluorescent ligand to provide quantitative pharmacology of ligand-receptor interactions in living cells in real time.
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Affiliation(s)
- Leigh A Stoddart
- Division of Physiology, Pharmacology and Neuroscience, School of Life Sciences, University of Nottingham, Nottingham, NG7 2UH, UK; Centre of Membrane Proteins and Receptors, University of Birmingham and University of Nottingham, The Midlands, UK; These authors contributed equally to this work
| | - Laura E Kilpatrick
- Division of Physiology, Pharmacology and Neuroscience, School of Life Sciences, University of Nottingham, Nottingham, NG7 2UH, UK; Centre of Membrane Proteins and Receptors, University of Birmingham and University of Nottingham, The Midlands, UK; These authors contributed equally to this work
| | - Stephen J Hill
- Division of Physiology, Pharmacology and Neuroscience, School of Life Sciences, University of Nottingham, Nottingham, NG7 2UH, UK; Centre of Membrane Proteins and Receptors, University of Birmingham and University of Nottingham, The Midlands, UK.
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Stoddart LA, Vernall AJ, Bouzo-Lorenzo M, Bosma R, Kooistra AJ, de Graaf C, Vischer HF, Leurs R, Briddon SJ, Kellam B, Hill SJ. Development of novel fluorescent histamine H 1-receptor antagonists to study ligand-binding kinetics in living cells. Sci Rep 2018; 8:1572. [PMID: 29371669 PMCID: PMC5785503 DOI: 10.1038/s41598-018-19714-2] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2017] [Accepted: 01/03/2018] [Indexed: 01/01/2023] Open
Abstract
The histamine H1-receptor (H1R) is an important mediator of allergy and inflammation. H1R antagonists have particular clinical utility in allergic rhinitis and urticaria. Here we have developed six novel fluorescent probes for this receptor that are very effective for high resolution confocal imaging, alongside bioluminescence resonance energy transfer approaches to monitor H1R ligand binding kinetics in living cells. The latter technology exploits the opportunities provided by the recently described bright bioluminescent protein NanoLuc when it is fused to the N-terminus of a receptor. Two different pharmacophores (mepyramine or the fragment VUF13816) were used to generate fluorescent H1R antagonists conjugated via peptide linkers to the fluorophore BODIPY630/650. Kinetic properties of the probes showed wide variation, with the VUF13816 analogues having much longer H1R residence times relative to their mepyramine-based counterparts. The kinetics of these fluorescent ligands could also be monitored in membrane preparations providing new opportunities for future drug discovery applications.
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Affiliation(s)
- Leigh A Stoddart
- Division of Pharmacology Physiology and Neuroscience, School of Life Sciences, University of Nottingham, Nottingham, NG7 2UH, UK
- Centre of Membrane Proteins and Receptors, University of Birmingham and University of Nottingham, Midlands, UK
| | - Andrea J Vernall
- School of Pharmacy, Division of Biomolecular Science and Medicinal Chemistry, Centre for Biomolecular Sciences, University of Nottingham, Nottingham, NG7 2RD, UK
| | - Monica Bouzo-Lorenzo
- Division of Pharmacology Physiology and Neuroscience, School of Life Sciences, University of Nottingham, Nottingham, NG7 2UH, UK
- Centre of Membrane Proteins and Receptors, University of Birmingham and University of Nottingham, Midlands, UK
| | - Reggie Bosma
- Department of Chemistry and Pharmaceutical Sciences, Division of Medicinal Chemistry, Amsterdam Institute for Molecules, Medicines and Systems (AIMMS), Vrije Universiteit, Amsterdam, PO Box 7161, Amsterdam, The Netherlands
| | - Albert J Kooistra
- Department of Chemistry and Pharmaceutical Sciences, Division of Medicinal Chemistry, Amsterdam Institute for Molecules, Medicines and Systems (AIMMS), Vrije Universiteit, Amsterdam, PO Box 7161, Amsterdam, The Netherlands
| | - Chris de Graaf
- Department of Chemistry and Pharmaceutical Sciences, Division of Medicinal Chemistry, Amsterdam Institute for Molecules, Medicines and Systems (AIMMS), Vrije Universiteit, Amsterdam, PO Box 7161, Amsterdam, The Netherlands
| | - Henry F Vischer
- Department of Chemistry and Pharmaceutical Sciences, Division of Medicinal Chemistry, Amsterdam Institute for Molecules, Medicines and Systems (AIMMS), Vrije Universiteit, Amsterdam, PO Box 7161, Amsterdam, The Netherlands
| | - Rob Leurs
- Department of Chemistry and Pharmaceutical Sciences, Division of Medicinal Chemistry, Amsterdam Institute for Molecules, Medicines and Systems (AIMMS), Vrije Universiteit, Amsterdam, PO Box 7161, Amsterdam, The Netherlands
| | - Stephen J Briddon
- Division of Pharmacology Physiology and Neuroscience, School of Life Sciences, University of Nottingham, Nottingham, NG7 2UH, UK
- Centre of Membrane Proteins and Receptors, University of Birmingham and University of Nottingham, Midlands, UK
| | - Barrie Kellam
- School of Pharmacy, Division of Biomolecular Science and Medicinal Chemistry, Centre for Biomolecular Sciences, University of Nottingham, Nottingham, NG7 2RD, UK.
- Centre of Membrane Proteins and Receptors, University of Birmingham and University of Nottingham, Midlands, UK.
| | - Stephen J Hill
- Division of Pharmacology Physiology and Neuroscience, School of Life Sciences, University of Nottingham, Nottingham, NG7 2UH, UK.
- Centre of Membrane Proteins and Receptors, University of Birmingham and University of Nottingham, Midlands, UK.
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