1
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Structure-guided optimization of light-activated chimeric G-protein-coupled receptors. Structure 2022; 30:1075-1087.e4. [PMID: 35588733 DOI: 10.1016/j.str.2022.04.012] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Revised: 03/22/2022] [Accepted: 04/22/2022] [Indexed: 01/11/2023]
Abstract
G-protein-coupled receptors (GPCRs) are the largest human receptor family and involved in virtually every physiological process. One hallmark of their function is specific coupling to selected signaling pathways. The ability to tune this coupling would make development of receptors with new capabilities possible. Complexes of GPCRs and G-proteins have recently been resolved at high resolution, but this information was in only few cases harnessed for rational receptor engineering. Here, we demonstrate structure-guided optimization of light-activated OptoXRs. Our hypothesis was that incorporation of GPCR-Gα contacts would lead to improved coupling. We first evaluated structure-based alignments for chimeric receptor fusion. We then show in a light-activated β2AR that including Gα contacts increased signaling 7- to 20-fold compared with other designs. In turn, contact elimination diminished function. Finally, this platform allowed optimization of a further OptoXR and spectral tuning. Our work exemplifies structure-based OptoXR development for targeted cell and network manipulation.
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2
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Merlin J, Park J, Vandekolk TH, Fabb SA, Allinne J, Summers RJ, Langmead CJ, Riddy DM. Multi-pathway in vitro pharmacological characterisation of specialised pro-resolving G protein-coupled receptors (SPM-GPCRs). Mol Pharmacol 2022; 101:246-256. [DOI: 10.1124/molpharm.121.000422] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2021] [Accepted: 01/25/2022] [Indexed: 11/22/2022] Open
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3
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Zhang X, Belousoff MJ, Zhao P, Kooistra AJ, Truong TT, Ang SY, Underwood CR, Egebjerg T, Šenel P, Stewart GD, Liang YL, Glukhova A, Venugopal H, Christopoulos A, Furness SGB, Miller LJ, Reedtz-Runge S, Langmead CJ, Gloriam DE, Danev R, Sexton PM, Wootten D. Differential GLP-1R Binding and Activation by Peptide and Non-peptide Agonists. Mol Cell 2020; 80:485-500.e7. [PMID: 33027691 DOI: 10.1016/j.molcel.2020.09.020] [Citation(s) in RCA: 91] [Impact Index Per Article: 22.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Revised: 09/04/2020] [Accepted: 09/14/2020] [Indexed: 12/15/2022]
Abstract
Peptide drugs targeting class B1 G-protein-coupled receptors (GPCRs) can treat multiple diseases; however, there remains substantial interest in the development of orally delivered non-peptide drugs. Here, we reveal unexpected overlap between signaling and regulation of the glucagon-like peptide-1 (GLP-1) receptor by the non-peptide agonist PF 06882961 and GLP-1 that was not observed for another compound, CHU-128. Compounds from these patent series, including PF 06882961, are currently in clinical trials for treatment of type 2 diabetes. High-resolution cryoelectron microscopy (cryo-EM) structures reveal that the binding sites for PF 06882961 and GLP-1 substantially overlap, whereas CHU-128 adopts a unique binding mode with a more open receptor conformation at the extracellular face. Structural differences involving extensive water-mediated hydrogen bond networks could be correlated to functional data to understand how PF 06882961, but not CHU-128, can closely mimic the pharmacological properties of GLP-1. These findings will facilitate rational structure-based discovery of non-peptide agonists targeting class B GPCRs.
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Affiliation(s)
- Xin Zhang
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC 3052, Australia
| | - Matthew J Belousoff
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC 3052, Australia
| | - Peishen Zhao
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC 3052, Australia
| | - Albert J Kooistra
- Department of Drug Design and Pharmacology, University of Copenhagen, Universitetsparken 2, 2100 Copenhagen, Denmark
| | - Tin T Truong
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC 3052, Australia
| | - Sheng Yu Ang
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC 3052, Australia
| | | | | | - Petr Šenel
- Apigenex, Poděbradská 173/5, Prague 9 190 00, Czech Republic
| | - Gregory D Stewart
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC 3052, Australia
| | - Yi-Lynn Liang
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC 3052, Australia
| | - Alisa Glukhova
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC 3052, Australia
| | - Hari Venugopal
- Ramaciotti Centre for Cryo-Electron Microscopy, Monash University, Clayton, VIC 3168, Australia
| | - Arthur Christopoulos
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC 3052, Australia
| | - Sebastian G B Furness
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC 3052, Australia
| | - Laurence J Miller
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Scottsdale, AZ 85259, USA
| | | | - Christopher J Langmead
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC 3052, Australia
| | - David E Gloriam
- Department of Drug Design and Pharmacology, University of Copenhagen, Universitetsparken 2, 2100 Copenhagen, Denmark
| | - Radostin Danev
- Graduate School of Medicine, University of Tokyo, N415, 7-3-1 Hongo, Bunkyo-ku, 113-0033 Tokyo, Japan.
| | - Patrick M Sexton
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC 3052, Australia.
| | - Denise Wootten
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC 3052, Australia.
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4
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Activation of the GLP-1 receptor by a non-peptidic agonist. Nature 2020; 577:432-436. [PMID: 31915381 DOI: 10.1038/s41586-019-1902-z] [Citation(s) in RCA: 98] [Impact Index Per Article: 24.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2019] [Accepted: 11/08/2019] [Indexed: 01/22/2023]
Abstract
Class B G-protein-coupled receptors are major targets for the treatment of chronic diseases, including diabetes and obesity1. Structures of active receptors reveal peptide agonists engage deep within the receptor core, leading to an outward movement of extracellular loop 3 and the tops of transmembrane helices 6 and 7, an inward movement of transmembrane helix 1, reorganization of extracellular loop 2 and outward movement of the intracellular side of transmembrane helix 6, resulting in G-protein interaction and activation2-6. Here we solved the structure of a non-peptide agonist, TT-OAD2, bound to the glucagon-like peptide-1 (GLP-1) receptor. Our structure identified an unpredicted non-peptide agonist-binding pocket in which reorganization of extracellular loop 3 and transmembrane helices 6 and 7 manifests independently of direct ligand interaction within the deep transmembrane domain pocket. TT-OAD2 exhibits biased agonism, and kinetics of G-protein activation and signalling that are distinct from peptide agonists. Within the structure, TT-OAD2 protrudes beyond the receptor core to interact with the lipid or detergent, providing an explanation for the distinct activation kinetics that may contribute to the clinical efficacy of this compound series. This work alters our understanding of the events that drive the activation of class B receptors.
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5
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Pham V, Zhu Y, Dal Maso E, Reynolds CA, Deganutti G, Atanasio S, Hick CA, Yang D, Christopoulos A, Hay DL, Furness SGB, Wang MW, Wootten D, Sexton PM. Deconvoluting the Molecular Control of Binding and Signaling at the Amylin 3 Receptor: RAMP3 Alters Signal Propagation through Extracellular Loops of the Calcitonin Receptor. ACS Pharmacol Transl Sci 2019; 2:183-197. [PMID: 32219220 PMCID: PMC7088965 DOI: 10.1021/acsptsci.9b00010] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2019] [Indexed: 12/18/2022]
Abstract
Amylin is coexpressed with insulin in pancreatic islet β-cells and has potent effects on gastric emptying and food intake. The effect of amylin on satiation has been postulated to involve AMY3 receptors (AMY3R) that are heteromers of the calcitonin receptor (CTR) and receptor activity-modifying protein 3 (RAMP3). Understanding the molecular control of signaling through the AMY3R is thus important for peptide drug targeting of this receptor. We have previously used alanine scanning mutagenesis to study the contribution of the extracellular surface of the CTR to binding and signaling initiated by calcitonin (CT) and related peptides (Dal Maso, E., et al. (2019) The molecular control of calcitonin receptor signaling. ACS Pharmacol. Transl. Sci. 2, 31-51). That work revealed ligand- and pathway-specific effects of mutation, with extracellular loops (ECLs) 2 and 3 particularly important in the distinct propagation of signaling mediated by individual peptides. In the current study, we have used equivalent alanine scanning of ECL2 and ECL3 of the CTR in the context of coexpression with RAMP3 to form AMY3Rs, to examine functional affinity and efficacy of peptides in cAMP accumulation and extracellular signal-regulated kinase (ERK) phosphorylation (pERK). The effect of mutation was determined on representatives of the three major distinct classes of CT peptide, salmon CT (sCT), human CT (hCT), and porcine CT (pCT), as well as rat amylin (rAmy) or human α-CGRP (calcitonin gene-related peptide, hCGRP) whose potency is enhanced by RAMP interaction. We demonstrate that the dynamic nature of CTR ECL2 and ECL3 in propagation of signaling is fundamentally altered when complexed with RAMP3 to form the AMY3R, despite only having predicted direct interactions with ECL2. Moreover, the work shows that the role of these loops in receptor signaling is highly peptide dependent, illustrating that even subtle changes to peptide sequence may change signaling output downstream of the receptor.
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Affiliation(s)
- Vi Pham
- Drug
Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville 3052, Victoria, Australia
| | - Yue Zhu
- The
National Center for Drug Screening and CAS Key Laboratory of Receptor
Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
- University
of Chinese Academy of Sciences, 19A Yuquan Road, Beijing 100049, China
| | - Emma Dal Maso
- Drug
Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville 3052, Victoria, Australia
| | | | - Giuseppe Deganutti
- School
of Biological Sciences, University of Essex, Wivenhoe Park, Colchester CO4 3SQ, U.K.
| | - Silvia Atanasio
- School
of Biological Sciences, University of Essex, Wivenhoe Park, Colchester CO4 3SQ, U.K.
| | - Caroline A. Hick
- Drug
Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville 3052, Victoria, Australia
| | - Dehua Yang
- The
National Center for Drug Screening and CAS Key Laboratory of Receptor
Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
| | - Arthur Christopoulos
- Drug
Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville 3052, Victoria, Australia
| | - Debbie L. Hay
- The
University of Auckland, School of Biological
Sciences, 3 Symonds Street, Auckland 1142, New Zealand
| | - Sebastian G. B. Furness
- Drug
Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville 3052, Victoria, Australia
| | - Ming-Wei Wang
- The
National Center for Drug Screening and CAS Key Laboratory of Receptor
Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
- University
of Chinese Academy of Sciences, 19A Yuquan Road, Beijing 100049, China
| | - Denise Wootten
- Drug
Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville 3052, Victoria, Australia
| | - Patrick M. Sexton
- Drug
Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville 3052, Victoria, Australia
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6
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Fletcher MM, Halls ML, Zhao P, Clydesdale L, Christopoulos A, Sexton PM, Wootten D. Glucagon-like peptide-1 receptor internalisation controls spatiotemporal signalling mediated by biased agonists. Biochem Pharmacol 2018; 156:406-419. [PMID: 30195733 DOI: 10.1016/j.bcp.2018.09.003] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2018] [Accepted: 09/05/2018] [Indexed: 12/29/2022]
Abstract
The glucagon-like peptide-1 receptor (GLP-1R) is a major therapeutic target in the treatment of type 2 diabetes due to its roles in regulating blood glucose and in promoting weight loss. Like many GPCRs, it is pleiotropically coupled, can be activated by multiple ligands and is subject to biased agonism. The GLP-1R undergoes agonist mediated receptor internalisation that may be associated with spatiotemporal control of signalling and biased agonism, although to date, this has not been extensively explored. Here, we investigate GLP-1R trafficking and its importance with regard to signalling, including the localisation of key signalling molecules, mediated by biased peptide agonists that are either endogenous GLP-1R ligands or are used clinically. Each of the agonists promoted receptor internalisation through a dynamin and caveolae dependent mechanism and traffic the receptor to both degradative and recycling pathways. This internalisation is important for signalling, with cAMP and ERK1/2 phoshorylation (pERK1/2) generated by both plasma membrane localised and internalised receptors. Further assessment of pERK1/2 revealed that all peptides induced nuclear ERK activity, but ligands, liraglutide and oxyntomodulin that are biased towards pERK1/2 relative to cAMP (when compared to GLP-1 and exendin-4), also stimulated pERK1/2 activity in the cytosol. This compartmentalisation of ERK1/2 signalling was reliant on receptor internalisation, with restriction of receptor localisation to the plasma membrane limiting ERK1/2 signalling to the cytosol. Thus, this study implicates a role of receptor internalisation in spatiotemporal control of ERK1/2 signalling that may contribute to GLP-1R biased agonism.
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Affiliation(s)
- Madeleine M Fletcher
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Faculty of Pharmacy and Pharmaceutical Sciences, Monash University, Parkville, Melbourne, Victoria 3052, Australia
| | - Michelle L Halls
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Faculty of Pharmacy and Pharmaceutical Sciences, Monash University, Parkville, Melbourne, Victoria 3052, Australia
| | - Peishen Zhao
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Faculty of Pharmacy and Pharmaceutical Sciences, Monash University, Parkville, Melbourne, Victoria 3052, Australia
| | - Lachlan Clydesdale
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Faculty of Pharmacy and Pharmaceutical Sciences, Monash University, Parkville, Melbourne, Victoria 3052, Australia
| | - Arthur Christopoulos
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Faculty of Pharmacy and Pharmaceutical Sciences, Monash University, Parkville, Melbourne, Victoria 3052, Australia
| | - Patrick M Sexton
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Faculty of Pharmacy and Pharmaceutical Sciences, Monash University, Parkville, Melbourne, Victoria 3052, Australia; School of Pharmacy, Fudan University, Shanghai 201203, China.
| | - Denise Wootten
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Faculty of Pharmacy and Pharmaceutical Sciences, Monash University, Parkville, Melbourne, Victoria 3052, Australia; School of Pharmacy, Fudan University, Shanghai 201203, China.
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7
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Liang YL, Khoshouei M, Glukhova A, Furness SGB, Zhao P, Clydesdale L, Koole C, Truong TT, Thal DM, Lei S, Radjainia M, Danev R, Baumeister W, Wang MW, Miller LJ, Christopoulos A, Sexton PM, Wootten D. Phase-plate cryo-EM structure of a biased agonist-bound human GLP-1 receptor-Gs complex. Nature 2018; 555:121-125. [PMID: 29466332 DOI: 10.1038/nature25773] [Citation(s) in RCA: 212] [Impact Index Per Article: 35.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2017] [Accepted: 01/17/2018] [Indexed: 12/20/2022]
Abstract
The class B glucagon-like peptide-1 (GLP-1) G protein-coupled receptor is a major target for the treatment of type 2 diabetes and obesity. Endogenous and mimetic GLP-1 peptides exhibit biased agonism-a difference in functional selectivity-that may provide improved therapeutic outcomes. Here we describe the structure of the human GLP-1 receptor in complex with the G protein-biased peptide exendin-P5 and a Gαs heterotrimer, determined at a global resolution of 3.3 Å. At the extracellular surface, the organization of extracellular loop 3 and proximal transmembrane segments differs between our exendin-P5-bound structure and previous GLP-1-bound GLP-1 receptor structure. At the intracellular face, there was a six-degree difference in the angle of the Gαs-α5 helix engagement between structures, which was propagated across the G protein heterotrimer. In addition, the structures differed in the rate and extent of conformational reorganization of the Gαs protein. Our structure provides insights into the molecular basis of biased agonism.
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Affiliation(s)
- Yi-Lynn Liang
- Drug Discovery Biology and Department of Pharmacology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville 3052, Victoria, Australia
| | - Maryam Khoshouei
- Department of Molecular Structural Biology, Max Planck Institute of Biochemistry, 82152 Martinsried, Germany
| | - Alisa Glukhova
- Drug Discovery Biology and Department of Pharmacology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville 3052, Victoria, Australia
| | - Sebastian G B Furness
- Drug Discovery Biology and Department of Pharmacology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville 3052, Victoria, Australia
| | - Peishen Zhao
- Drug Discovery Biology and Department of Pharmacology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville 3052, Victoria, Australia
| | - Lachlan Clydesdale
- Drug Discovery Biology and Department of Pharmacology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville 3052, Victoria, Australia
| | - Cassandra Koole
- Drug Discovery Biology and Department of Pharmacology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville 3052, Victoria, Australia
| | - Tin T Truong
- Drug Discovery Biology and Department of Pharmacology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville 3052, Victoria, Australia
| | - David M Thal
- Drug Discovery Biology and Department of Pharmacology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville 3052, Victoria, Australia
| | - Saifei Lei
- University of Chinese Academy of Sciences, 19A Yuquan Road, Beijing 100049, China.,The National Center for Drug Screening and CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
| | - Mazdak Radjainia
- Drug Discovery Biology and Department of Pharmacology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville 3052, Victoria, Australia.,FEI, 5651 GG Eindhoven, The Netherlands
| | - Radostin Danev
- Department of Molecular Structural Biology, Max Planck Institute of Biochemistry, 82152 Martinsried, Germany
| | - Wolfgang Baumeister
- Department of Molecular Structural Biology, Max Planck Institute of Biochemistry, 82152 Martinsried, Germany
| | - Ming-Wei Wang
- University of Chinese Academy of Sciences, 19A Yuquan Road, Beijing 100049, China.,The National Center for Drug Screening and CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China.,School of Pharmacy, Fudan University, Shanghai 201203, China
| | - Laurence J Miller
- Drug Discovery Biology and Department of Pharmacology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville 3052, Victoria, Australia.,Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Scottsdale, Arizona 85259, USA
| | - Arthur Christopoulos
- Drug Discovery Biology and Department of Pharmacology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville 3052, Victoria, Australia
| | - Patrick M Sexton
- Drug Discovery Biology and Department of Pharmacology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville 3052, Victoria, Australia.,School of Pharmacy, Fudan University, Shanghai 201203, China
| | - Denise Wootten
- Drug Discovery Biology and Department of Pharmacology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville 3052, Victoria, Australia
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8
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Mansouri M, Berger P. Multigene delivery in mammalian cells: Recent advances and applications. Biotechnol Adv 2018; 36:871-879. [PMID: 29374595 DOI: 10.1016/j.biotechadv.2018.01.012] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2017] [Revised: 01/19/2018] [Accepted: 01/20/2018] [Indexed: 12/27/2022]
Abstract
Systems for multigene delivery in mammalian cells, particularly in the context of genome engineering, have gained a lot of attention in biomolecular research and medicine. Initially these methods were based on RNA polymerase II promoters and were used for the production of protein complexes and for applications in cell biology such as reprogramming of somatic cells to stem cells. Emerging technologies such as CRISPR/Cas9-based genome engineering, which enable any alteration at the genomic level of an organism, require additional elements including U6-driven expression cassettes for RNA expression and homology constructs for designed genome modifications. For these applications, systems with high DNA capacity, flexibility and transfer rates are needed. In this article, we briefly give an update on some of recent strategies that facilitate multigene assembly and delivery into mammalian cells. Also, we review applications in various fields of biology that rely on multigene delivery systems.
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Affiliation(s)
- Maysam Mansouri
- Paul Scherrer Institute, Biomolecular Research, Applied Molecular Biology, CH-5232 Villigen, Switzerland
| | - Philipp Berger
- Paul Scherrer Institute, Biomolecular Research, Applied Molecular Biology, CH-5232 Villigen, Switzerland.
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9
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Characterization of signalling and regulation of common calcitonin receptor splice variants and polymorphisms. Biochem Pharmacol 2017; 148:111-129. [PMID: 29277692 DOI: 10.1016/j.bcp.2017.12.016] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Accepted: 12/19/2017] [Indexed: 01/27/2023]
Abstract
The calcitonin receptor (CTR) is a class B G protein-coupled receptor that is a therapeutic target for the treatment of hypercalcaemia of malignancy, Paget's disease and osteoporosis. In primates, the CTR is subject to alternative splicing, with a unique, primate-specific splice variant being preferentially expressed in reproductive organs, lung and kidney. In addition, humans possess a common non-synonymous single-nucleotide polymorphism (SNP) encoding a proline/leucine substitution in the C-terminal tail. In low power studies, the leucine polymorphism has been associated with increased risk of osteoporosis in East Asian populations and, independently, with increased risk of kidney stone disease in a central Asian population. The CTR is pleiotropically coupled, though the relative physiological importance of these pathways is poorly understood. Using both COS-7 and HEK293 cells recombinantly expressing human CTR, we have characterized both splice variant and polymorphism dependent response to CTs from several species in key signalling pathways and competition binding assays. These data indicate that the naturally occurring changes to the intracellular face of CTR alter ligand affinity and signalling, in a pathway and agonist dependent manner. These results further support the potential for these primate-specific CTR variants to engender different physiological responses. In addition, we report that the CTR exhibits constitutive internalization, independent of splice variant and polymorphism and this profile is unaltered by peptide binding.
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10
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NBPF7 promotes the proliferation of α-catenin-knockdown HaCaT cells via functional interaction with the NF-κB pathway. Oncotarget 2017; 8:65800-65808. [PMID: 29029473 PMCID: PMC5630373 DOI: 10.18632/oncotarget.19480] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2017] [Accepted: 06/29/2017] [Indexed: 12/24/2022] Open
Abstract
Loss of key components that form cell-cell adherens junctions, such as α-catenin, triggers severe epidermal hyperproliferation. However, the underlying molecular mechanisms remain largely unknown. We report here that neuroblastoma breakpoint family (NBPF) genes are upregulated and that NBPF7 specifically promotes cellular proliferation of α-catenin-silenced HaCaT cells through functional linkage with the NF-κB pathway. Genome-wide profiling of HaCaT cells shows that NBPF genes are upregulated following α-catenin knockdown. Data from western blot analyses are consistent with the activation of the NF-κB pathway as well as increased expression of NBPF7 by α-catenin knockdown. Co-immunoprecipitation assays indicate that NBPF7 could be detected in endogenous activated NF-κB immunoprecipitates. Immunoflurence analyses demonstrate that NBPF7 co-localizes with activated NF-κB in the nucleus after α-catenin silencing. Moreover, inhibition of NBPF7 decreases the proliferation of HaCaT cells and abolishes the enhanced proliferation associated with α-catenin knockdown in HaCaT cells. These results indicate that NBPF7 plays a key role in the α-catenin signaling pathway that regulates cell proliferation of keratinocytes. Our findings suggest that the classical NF-κB pathway plays a critical role in cellular proliferation and that NBPF7 is a functional mediator for α-catenin in the regulation of keratinocyte growth.
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11
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Using nanoBRET and CRISPR/Cas9 to monitor proximity to a genome-edited protein in real-time. Sci Rep 2017; 7:3187. [PMID: 28600500 PMCID: PMC5466623 DOI: 10.1038/s41598-017-03486-2] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2016] [Accepted: 04/28/2017] [Indexed: 12/15/2022] Open
Abstract
Bioluminescence resonance energy transfer (BRET) has been a vital tool for understanding G protein-coupled receptor (GPCR) function. It has been used to investigate GPCR-protein and/or -ligand interactions as well as GPCR oligomerisation. However the utility of BRET is limited by the requirement that the fusion proteins, and in particular the donor, need to be exogenously expressed. To address this, we have used CRISPR/Cas9-mediated homology-directed repair to generate protein-Nanoluciferase (Nluc) fusions under endogenous promotion, thus allowing investigation of proximity between the genome-edited protein and an exogenously expressed protein by BRET. Here we report BRET monitoring of GPCR-mediated β-arrestin2 recruitment and internalisation where the donor luciferase was under endogenous promotion, in live cells and in real time. We have investigated the utility of CRISPR/Cas9 genome editing to create genome-edited fusion proteins that can be used as BRET donors and propose that this strategy can be used to overcome the need for exogenous donor expression.
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12
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Characterization of signal bias at the GLP-1 receptor induced by backbone modification of GLP-1. Biochem Pharmacol 2017; 136:99-108. [PMID: 28363772 DOI: 10.1016/j.bcp.2017.03.018] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2017] [Accepted: 03/27/2017] [Indexed: 12/23/2022]
Abstract
The glucagon-like peptide-1 receptor (GLP-1R) is a class B G protein-coupled receptor that is a major therapeutic target for the treatment of type 2 diabetes. Activation of this receptor promotes insulin secretion and blood glucose regulation. The GLP-1R can initiate signaling through several intracellular pathways upon activation by GLP-1. GLP-1R ligands that preferentially stimulate subsets among the natural signaling pathways ("biased agonists") could be useful as tools for elucidating the consequences of specific pathways and might engender therapeutic agents with tailored effects. Using HEK-293 cells recombinantly expressing human GLP-1R, we have previously reported that backbone modification of GLP-1, via replacement of selected α-amino acid residues with β-amino acid residues, generates GLP-1 analogues with distinctive preferences for promoting G protein activation versus β-arrestin recruitment. Here, we have explored the influence of cell background across these two parameters and expanded our analysis to include affinity and other key signaling pathways (intracellular calcium mobilization and ERK phosphorylation) using recombinant human GLP-1R expressed in a CHO cell background, which has been used extensively to demonstrate biased agonism of GLP-1R ligands. The new data indicate that α/β-peptide analogues of GLP-1 exhibit a range of distinct bias profiles relative to GLP-1 and that broad assessment of signaling endpoints is required to reveal the spectrum of behavior of modified peptides. These results support the view that backbone modification via α→β amino acid replacement can enable rapid discovery of peptide hormone analogues that display substantial signal bias at a cognate GPCR.
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13
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Jensen DD, Godfrey CB, Niklas C, Canals M, Kocan M, Poole DP, Murphy JE, Alemi F, Cottrell GS, Korbmacher C, Lambert NA, Bunnett NW, Corvera CU. The bile acid receptor TGR5 does not interact with β-arrestins or traffic to endosomes but transmits sustained signals from plasma membrane rafts. J Biol Chem 2013; 288:22942-60. [PMID: 23818521 DOI: 10.1074/jbc.m113.455774] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
TGR5 is a G protein-coupled receptor that mediates bile acid (BA) effects on energy balance, inflammation, digestion, and sensation. The mechanisms and spatiotemporal control of TGR5 signaling are poorly understood. We investigated TGR5 signaling and trafficking in transfected HEK293 cells and colonocytes (NCM460) that endogenously express TGR5. BAs (deoxycholic acid (DCA), taurolithocholic acid) and the selective agonists oleanolic acid and 3-(2-chlorophenyl)-N-(4-chlorophenyl)-N, 5-dimethylisoxazole-4-carboxamide stimulated cAMP formation but did not induce TGR5 endocytosis or recruitment of β-arrestins, as assessed by confocal microscopy. DCA, taurolithocholic acid, and oleanolic acid did not stimulate TGR5 association with β-arrestin 1/2 or G protein-coupled receptor kinase (GRK) 2/5/6, as determined by bioluminescence resonance energy transfer. 3-(2-chlorophenyl)-N-(4-chlorophenyl)-N, 5-dimethylisoxazole-4-carboxamide stimulated a low level of TGR5 interaction with β-arrestin 2 and GRK2. DCA induced cAMP formation at the plasma membrane and cytosol, as determined using exchange factor directly regulated by cAMP (Epac2)-based reporters, but cAMP signals did not desensitize. AG1478, an inhibitor of epidermal growth factor receptor tyrosine kinase, the metalloprotease inhibitor batimastat, and methyl-β-cyclodextrin and filipin, which block lipid raft formation, prevented DCA stimulation of ERK1/2. Bioluminescence resonance energy transfer analysis revealed TGR5 and EGFR interactions that were blocked by disruption of lipid rafts. DCA stimulated TGR5 redistribution to plasma membrane microdomains, as localized by immunogold electron microscopy. Thus, TGR5 does not interact with β-arrestins, desensitize, or traffic to endosomes. TGR5 signals from plasma membrane rafts that facilitate EGFR interaction and transactivation. An understanding of the spatiotemporal control of TGR5 signaling provides insights into the actions of BAs and therapeutic TGR5 agonists/antagonists.
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Affiliation(s)
- Dane D Jensen
- Monash Institute of Pharmaceutical Sciences, 381 Royal Parade, Parkville, Victoria 3052, Australia
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