1
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Samuel CS, Li Y, Wang Y, Widdop RE. Functional crosstalk between angiotensin receptors (types 1 and 2) and relaxin family peptide receptor 1 (RXFP1): Implications for the therapeutic targeting of fibrosis. Br J Pharmacol 2024; 181:2302-2318. [PMID: 36560925 DOI: 10.1111/bph.16019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Revised: 12/15/2022] [Accepted: 12/20/2022] [Indexed: 12/24/2022] Open
Abstract
Class A, rhodopsin-like, G-protein-coupled receptors (GPCRs) are by far the largest class of GPCRs and are integral membrane proteins used by various cells to convert extracellular signals into intracellular responses. Initially, class A GPCRs were believed to function as monomers, but a growing body of evidence has emerged to suggest that these receptors can function as homodimers and heterodimers and can undergo functional crosstalk to influence the actions of agonists or antagonists acting at each receptor. This review will focus on the angiotensin type 1 (AT1) and type 2 (AT2) receptors, as well as the relaxin family peptide receptor 1 (RXFP1), each of which have their unique characteristics but have been demonstrated to undergo some level of interaction when appropriately co-expressed, which influences the function of each receptor. In particular, this receptor functional crosstalk will be discussed in the context of fibrosis, the tissue scarring that results from a failed wound-healing response to injury, and which is a hallmark of chronic disease and related organ dysfunction. LINKED ARTICLES: This article is part of a themed issue Therapeutic Targeting of G Protein-Coupled Receptors: hot topics from the Australasian Society of Clinical and Experimental Pharmacologists and Toxicologists 2021 Virtual Annual Scientific Meeting. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v181.14/issuetoc.
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Affiliation(s)
- Chrishan S Samuel
- Cardiovascular Disease Program, Monash Biomedicine Discovery Institute and Department of Pharmacology, Monash University, Clayton, Victoria, Australia
- Department of Biochemistry and Molecular Biology, The University of Melbourne, Parkville, Victoria, Australia
| | - Yifang Li
- Cardiovascular Disease Program, Monash Biomedicine Discovery Institute and Department of Pharmacology, Monash University, Clayton, Victoria, Australia
| | - Yan Wang
- Cardiovascular Disease Program, Monash Biomedicine Discovery Institute and Department of Pharmacology, Monash University, Clayton, Victoria, Australia
| | - Robert E Widdop
- Cardiovascular Disease Program, Monash Biomedicine Discovery Institute and Department of Pharmacology, Monash University, Clayton, Victoria, Australia
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2
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Bresinsky M, Shahraki A, Kolb P, Pockes S, Schihada H. Development of Fluorescent AF64394 Analogues Enables Real-Time Binding Studies for the Orphan Class A GPCR GPR3. J Med Chem 2023; 66:15025-15041. [PMID: 37907069 PMCID: PMC10641823 DOI: 10.1021/acs.jmedchem.3c01707] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2023] [Revised: 10/16/2023] [Accepted: 10/18/2023] [Indexed: 11/02/2023]
Abstract
The orphan G protein-coupled receptor (oGPCR) GPR3 represents a potential drug target for the treatment of Alzheimer's disease and metabolic disorders. However, the limited toolbox of pharmacological assays hampers the development of advanced ligands. Here, we developed a signaling pathway-independent readout of compound-GPR3 interaction. Starting from computational binding pose predictions of the most potent GPR3 ligand, we designed a series of fluorescent AF64394 analogues and assessed their suitability for BRET-based binding studies. The most potent ligand, 45 (UR-MB-355), bound to GPR3 and closely related receptors, GPR6 and GPR12, with similar submicromolar affinities. Furthermore, we found that 45 engages GPR3 in a distinct mode compared to AF64394, and coincubation studies with the GPR3 agonist diphenyleneiodonium chloride revealed allosteric modulation of 45 binding. These insights provide new cues for the pharmacological manipulation of GPR3 activity. This novel binding assay will foster the development of future drugs acting through these pharmacologically attractive oGPCRs.
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Affiliation(s)
- Merlin Bresinsky
- Institute
of Pharmacy, University of Regensburg, Universitätsstraße 31, 93053 Regensburg, Germany
| | - Aida Shahraki
- Department
of Pharmaceutical Chemistry, University
of Marburg, Marbacher Weg 8, 35032 Marburg, Germany
| | - Peter Kolb
- Department
of Pharmaceutical Chemistry, University
of Marburg, Marbacher Weg 8, 35032 Marburg, Germany
| | - Steffen Pockes
- Institute
of Pharmacy, University of Regensburg, Universitätsstraße 31, 93053 Regensburg, Germany
- Department
of Medicinal Chemistry, Institute for Therapeutics Discovery and Development, University of Minnesota, Minneapolis, Minnesota 55414, United States
| | - Hannes Schihada
- Department
of Pharmaceutical Chemistry, University
of Marburg, Marbacher Weg 8, 35032 Marburg, Germany
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3
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Babin KM, Karim JA, Gordon PH, Lennon J, Dickson A, Pioszak AA. Adrenomedullin 2/intermedin is a slow off-rate, long-acting endogenous agonist of the adrenomedullin 2 G protein-coupled receptor. J Biol Chem 2023:104785. [PMID: 37146967 DOI: 10.1016/j.jbc.2023.104785] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Revised: 04/20/2023] [Accepted: 05/01/2023] [Indexed: 05/07/2023] Open
Abstract
Adrenomedullin 2/intermedin (AM2/IMD), adrenomedullin (AM), and calcitonin gene-related peptide (CGRP) have signaling functions in the cardiovascular, lymphatic, and nervous systems by activating three heterodimeric receptors comprised of the class B GPCR CLR and a RAMP1, -2, or -3 modulatory subunit. CGRP and AM prefer the RAMP1 and RAMP2/3 complexes, respectively, whereas AM2/IMD is thought to be relatively non-selective. Accordingly, AM2/IMD exhibits overlapping actions with CGRP and AM, so the rationale for this third agonist for the CLR-RAMP complexes is unclear. Here, we report that AM2/IMD is kinetically selective for CLR-RAMP3, known as the AM2R, and we define the structural basis for its distinct kinetics. In live cell biosensor assays, AM2/IMD-AM2R elicited substantially longer duration cAMP signaling than the eight other peptide-receptor combinations. AM2/IMD and AM bound the AM2R with similar equilibrium affinities, but AM2/IMD had a much slower off-rate and longer receptor residence time, thus explaining its prolonged signaling capacity. Peptide and receptor chimeras and mutagenesis were used to map the regions responsible for the distinct binding and signaling kinetics to the AM2/IMD mid-region and the RAMP3 extracellular domain (ECD). Molecular dynamics simulations revealed how the former forms stable interactions at the CLR ECD-transmembrane domain interface and how the latter augments the CLR ECD binding pocket to anchor the AM2/IMD C-terminus. These two strong binding components only combine in the AM2R. Our findings uncover AM2/IMD-AM2R as a cognate pair with unique temporal features, reveal how AM2/IMD and RAMP3 collaborate to shape CLR signaling, and have significant implications for AM2/IMD biology.
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Affiliation(s)
- Katie M Babin
- Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104
| | - Jordan A Karim
- Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104
| | - Peyton H Gordon
- Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104
| | - James Lennon
- Departments of Biochemistry and Molecular Biology and Computational Mathematics, Science and Engineering, Michigan State University, East Lansing, MI 48824
| | - Alex Dickson
- Departments of Biochemistry and Molecular Biology and Computational Mathematics, Science and Engineering, Michigan State University, East Lansing, MI 48824.
| | - Augen A Pioszak
- Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104.
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4
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Babin KM, Karim JA, Gordon PH, Lennon J, Dickson A, Pioszak AA. Adrenomedullin 2/intermedin is a slow off-rate, long-acting endogenous agonist of the adrenomedullin 2 G protein-coupled receptor. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.13.523955. [PMID: 36711519 PMCID: PMC9882245 DOI: 10.1101/2023.01.13.523955] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
The signaling peptides adrenomedullin 2/intermedin (AM2/IMD), adrenomedullin (AM), and CGRP have overlapping and distinct functions in the cardiovascular, lymphatic, and nervous systems by activating three shared receptors comprised of the class B GPCR CLR in complex with a RAMP1, -2, or -3 modulatory subunit. Here, we report that AM2/IMD, which is thought to be a non-selective agonist, is kinetically selective for CLR-RAMP3, known as the AM 2 R. AM2/IMD-AM 2 R elicited substantially longer duration cAMP signaling than the eight other peptide-receptor combinations due to AM2/IMD slow off-rate binding kinetics. The regions responsible for the slow off-rate were mapped to the AM2/IMD mid-region and the RAMP3 extracellular domain. MD simulations revealed how these bestow enhanced stability to the complex. Our results uncover AM2/IMD-AM 2 R as a cognate pair with unique temporal features, define the mechanism of kinetic selectivity, and explain how AM2/IMD and RAMP3 collaborate to shape the signaling output of a clinically important GPCR.
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Affiliation(s)
- Katie M. Babin
- Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104
| | - Jordan A. Karim
- Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104
| | - Peyton H. Gordon
- Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104
| | - James Lennon
- Departments of Biochemistry and Molecular Biology and Computational Mathematics, Science and Engineering, Michigan State University, East Lansing, MI 48824
| | - Alex Dickson
- Departments of Biochemistry and Molecular Biology and Computational Mathematics, Science and Engineering, Michigan State University, East Lansing, MI 48824
| | - Augen A. Pioszak
- Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104
- Lead contact
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5
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Grätz L, Müller C, Pegoli A, Schindler L, Bernhardt G, Littmann T. Insertion of Nanoluc into the Extracellular Loops as a Complementary Method To Establish BRET-Based Binding Assays for GPCRs. ACS Pharmacol Transl Sci 2022; 5:1142-1155. [PMID: 36407949 PMCID: PMC9667534 DOI: 10.1021/acsptsci.2c00162] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2022] [Indexed: 11/13/2022]
Abstract
Luminescence-based techniques play an increasingly important role in all areas of biochemical research, including investigations on G protein-coupled receptors (GPCRs). One quite recent and popular addition has been made by introducing bioluminescence resonance energy transfer (BRET)-based binding assays for GPCRs, which are based on the fusion of nanoluciferase (Nluc) to the N-terminus of the receptor and the occurring energy transfer via BRET to a bound fluorescent ligand. However, being based on BRET, the technique is strongly dependent on the distance/orientation between the luciferase and the fluorescent ligand. Here we describe an alternative strategy to establish BRET-based binding assays for GPCRs, where the N-terminal fusion of Nluc did not result in functioning test systems with our fluorescent ligands (e.g., for the neuropeptide Y Y1 receptor (Y1R) and the neurotensin receptor type 1 (NTS1R)). Instead, we introduced Nluc into their second extracellular loop and we obtained binding data for the fluorescent ligands and reported standard ligands (in saturation and competition binding experiments, respectively) comparable to data from the literature. The strategy was transferred to the angiotensin II receptor type 1 (AT1R) and the M1 muscarinic acetylcholine receptor (M1R), which led to affinity estimates comparable to data from radioligand binding experiments. Additionally, an analysis of the binding kinetics of all fluorescent ligands at their respective target was performed using the newly described receptor/Nluc-constructs.
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Affiliation(s)
| | - Christoph Müller
- Institute of Pharmacy, Faculty of Chemistry and Pharmacy, University of Regensburg, Universitätsstrasse 31, D-93053 Regensburg, Germany
| | | | - Lisa Schindler
- Institute of Pharmacy, Faculty of Chemistry and Pharmacy, University of Regensburg, Universitätsstrasse 31, D-93053 Regensburg, Germany
| | - Günther Bernhardt
- Institute of Pharmacy, Faculty of Chemistry and Pharmacy, University of Regensburg, Universitätsstrasse 31, D-93053 Regensburg, Germany
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6
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Structural Insights into the Unique Modes of Relaxin-Binding and Tethered-Agonist Mediated Activation of RXFP1 and RXFP2. J Mol Biol 2021; 433:167217. [PMID: 34454945 DOI: 10.1016/j.jmb.2021.167217] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 08/09/2021] [Accepted: 08/19/2021] [Indexed: 01/01/2023]
Abstract
Our poor understanding of the mechanism by which the peptide-hormone H2 relaxin activates its G protein coupled receptor, RXFP1 and the related receptor RXFP2, has hindered progress in its therapeutic development. Both receptors possess large ectodomains, which bind H2 relaxin, and contain an N-terminal LDLa module that is essential for receptor signaling and postulated to be a tethered agonist. Here, we show that a conserved motif (GDxxGWxxxF), C-terminal to the LDLa module, is critical for receptor activity. Importantly, this motif adopts different structures in RXFP1 and RXFP2, suggesting distinct activation mechanisms. For RXFP1, the motif is flexible, weakly associates with the LDLa module, and requires H2 relaxin binding to stabilize an active conformation. Conversely, the GDxxGWxxxF motif in RXFP2 is more closely associated with the LDLa module, forming an essential binding interface for H2 relaxin. These differences in the activation mechanism will aid drug development targeting these receptors.
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7
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Veenstra JA. Ambulacrarian insulin-related peptides and their putative receptors suggest how insulin and similar peptides may have evolved from insulin-like growth factor. PeerJ 2021; 9:e11799. [PMID: 34316411 PMCID: PMC8286064 DOI: 10.7717/peerj.11799] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Accepted: 06/25/2021] [Indexed: 01/23/2023] Open
Abstract
Background Some insulin/IGF-related peptides (irps) stimulate a receptor tyrosine kinase (RTK) that transfers the extracellular hormonal signal into an intracellular response. Other irps, such as relaxin, do not use an RTK, but a G-protein coupled receptor (GPCR). This is unusual since evolutionarily related hormones typically either use the same or paralogous receptors. In arthropods three different irps, i.e. arthropod IGF, gonadulin and Drosophila insulin-like peptide 7 (dilp7), likely evolved from a gene triplication, as in several species genes encoding these three peptides are located next to one another on the same chromosomal fragment. These arthropod irps have homologs in vertebrates, suggesting that the initial gene triplication was perhaps already present in the last common ancestor of deuterostomes and protostomes. It would be interesting to know whether this is indeed so and how insulin might be related to this trio of irps. Methodology Genes encoding irps as well as their putative receptors were identified in genomes and transcriptomes from echinoderms and hemichordates. Results A similar triplet of genes coding for irps also occurs in some ambulacrarians. Two of these are orthologs of arthropod IGF and dilp7 and the third is likely a gonadulin ortholog. In echinoderms, two novel irps emerged, gonad stimulating substance (GSS) and multinsulin, likely from gene duplications of the IGF and dilp7-like genes respectively. The structures of GSS diverged considerably from IGF, which would suggest they use different receptors from IGF, but no novel irp receptors evolved. If IGF and GSS use different receptors, and the evolution of GSS from a gene duplication of IGF is not associated with the appearance of a novel receptor, while irps are known to use two different types of receptors, the ancestor of GSS and IGF might have acted on both types of receptors while one or both of its descendants act on only one. There are three ambulacrarian GPCRs that have amino acid sequences suggestive of being irp GPCRs, two of these are orthologs of the gonadulin and dilp7 receptors. This suggests that the third might be an IGF receptor, and that by deduction, GSS only acts on the RTK. The evolution of GSS from IGF may represent a pattern, where IGF gene duplications lead to novel genes coding for shorter peptides that activate an RTK. It is likely this is how insulin and the insect neuroendocrine irps evolved independently from IGF. Conclusion The local gene triplication described from arthropods that yielded three genes encoding irps was already present in the last common ancestor of protostomes and deuterostomes. It seems plausible that irps, such as those produced by neuroendocrine cells in the brain of insects and echinoderm GSS evolved independently from IGF and, thus, are not true orthologs, but the result of convergent evolution.
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Affiliation(s)
- Jan A Veenstra
- INCIA UMR 5287 CNRS, Université de Bordeaux, Pessac, Gironde, France
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8
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Chakraborty A, Pinar AA, Lam M, Bourke JE, Royce SG, Selomulya C, Samuel CS. Pulmonary myeloid cell uptake of biodegradable nanoparticles conjugated with an anti-fibrotic agent provides a novel strategy for treating chronic allergic airways disease. Biomaterials 2021; 273:120796. [PMID: 33894403 DOI: 10.1016/j.biomaterials.2021.120796] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Revised: 03/26/2021] [Accepted: 03/28/2021] [Indexed: 01/06/2023]
Abstract
Asthma (chronic allergic airways disease, AAD) is characterized by airway inflammation (AI), airway remodeling (AWR) and airway hyperresponsiveness (AHR). Current treatments for AAD mainly focus on targeting AI and its contribution AHR, with the use of corticosteroids. However, there are no therapies for the direct treatment of AWR, which can contribute to airway obstruction, AHR and corticosteroid resistance independently of AI. The acute heart failure drug, serelaxin (recombinant human gene-2 relaxin, RLX), has potential anti-remodeling and anti-fibrotic effects but only when continuously infused or injected to overcome its short half-life. To alleviate this limitation, we conjugated serelaxin to biodegradable and noninflammatory nanoparticles (NP-RLX) and evaluated their therapeutic potential on measures of AI, AWR and AHR, when intranasally delivered to a preclinical rodent model of chronic AAD and TGF-β1-stimulated collagen gel contraction from asthma patient-derived myofibroblasts. NP-RLX was preferentially taken-up by CD206+-infiltrating and CD68+-tissue resident alveolar macrophages. Furthermore, NP-RLX ameliorated the chronic AAD-induced AI, pro-inflammatory cytokines (IL-1β, IL-6, TNF-α), chemokines (CCL2, CCL11) and the pro-fibrotic TGF-β1/IL-1β axis on AWR and resulting AHR, as well as human myofibroblast-induced collagen gel contraction, to a similar extent as unconjugated RLX. Hence, NP-RLX represents a novel strategy for treating the central features of asthma.
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Affiliation(s)
- Amlan Chakraborty
- Monash Biomedicine Discovery Institute and Department of Pharmacology, Monash University, Clayton, Victoria, Australia; Department of Chemical Engineering, Monash University, Clayton, Victoria, Australia
| | - Anita A Pinar
- Monash Biomedicine Discovery Institute and Department of Pharmacology, Monash University, Clayton, Victoria, Australia
| | - Maggie Lam
- Monash Biomedicine Discovery Institute and Department of Pharmacology, Monash University, Clayton, Victoria, Australia
| | - Jane E Bourke
- Monash Biomedicine Discovery Institute and Department of Pharmacology, Monash University, Clayton, Victoria, Australia
| | - Simon G Royce
- Monash Biomedicine Discovery Institute and Department of Pharmacology, Monash University, Clayton, Victoria, Australia; Department of Clinical Pathology and Department of Paediatrics, The University of Melbourne, Parkville, Victoria, Australia
| | - Cordelia Selomulya
- School of Chemical Engineering, UNSW Sydney, New South Wales, Australia.
| | - Chrishan S Samuel
- Monash Biomedicine Discovery Institute and Department of Pharmacology, Monash University, Clayton, Victoria, Australia; Department of Biochemistry and Molecular Biology, The University of Melbourne, Parkville, Victoria, Australia.
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9
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Xie H, Zhang JF, Li Q. Identification and analysis of genes associated with lung adenocarcinoma by integrated bioinformatics methods. Ann Hum Genet 2021; 85:125-137. [PMID: 33847374 DOI: 10.1111/ahg.12418] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2020] [Revised: 02/14/2021] [Accepted: 03/08/2021] [Indexed: 01/21/2023]
Abstract
Lung adenocarcinoma (LUAD) is one of the most common forms of lung cancer, with a very high mortality rate. Although the treatments available for LUAD have become more effective in recent years, significant improvement is still needed. Advances in sequencing technologies and bioinformatics analysis have enabled new approaches to be developed for identifying drug targets. In this work we utilized data from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) databases to identify hub genes related to LUAD through Weighted Gene Correlation Network Analysis (WGCNA) and other bioinformatics methods, with the goal of identifying new drug targets for cancer treatment.
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Affiliation(s)
- Hui Xie
- Department of Radiation Oncology, Affiliated Hospital (Clinical College) of Xiangnan University, Chenzhou, 423000, P. R. China.,Key Laboratory of Medical Imaging and Artifical Intelligence of Hunan Province, Chenzhou, 423000, P. R. China
| | - Jian-Fang Zhang
- Department of Physical examination, Beihu Centers for Disease Control and Prevention, Chenzhou, 423000, P. R. China
| | - Qing Li
- Key Laboratory of Medical Imaging and Artifical Intelligence of Hunan Province, Chenzhou, 423000, P. R. China.,Department of Interventional vascular surgery, Affiliated Hospital (Clinical College) of Xiangnan University, Chenzhou, 423000, P. R. China
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10
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Syed AJ, Anderson JC. Applications of bioluminescence in biotechnology and beyond. Chem Soc Rev 2021; 50:5668-5705. [DOI: 10.1039/d0cs01492c] [Citation(s) in RCA: 51] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Bioluminescent probes have hugely benefited from the input of synthetic chemistry and protein engineering. Here we review the latest applications of these probes in biotechnology and beyond, with an eye on current limitations and future directions.
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Affiliation(s)
- Aisha J. Syed
- Department of Chemistry
- University College London
- London
- UK
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11
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BRET- and fluorescence anisotropy-based assays for real-time monitoring of ligand binding to M 2 muscarinic acetylcholine receptors. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2020; 1868:118930. [PMID: 33347921 DOI: 10.1016/j.bbamcr.2020.118930] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 09/08/2020] [Revised: 11/26/2020] [Accepted: 12/11/2020] [Indexed: 12/14/2022]
Abstract
BRET and fluorescence anisotropy (FA) are two fluorescence-based techniques used for the characterization of ligand binding to G protein-coupled receptors (GPCRs) and both allow monitoring of ligand binding in real time. In this study, we present the first direct comparison of BRET-based and FA-based binding assays using the human M2 muscarinic acetylcholine receptor (M2R) and two TAMRA (5-carboxytetramethylrhodamine)-labeled fluorescent ligands as a model system. The determined fluorescent ligand affinities from both assays were in good agreement with results obtained from radioligand competition binding experiments. The assays yielded real-time kinetic binding data revealing differences in the mechanism of binding for the investigated fluorescent probes. Furthermore, the investigation of various unlabeled M2R ligands yielded pharmacological profiles in accordance with earlier reported data. Taken together, this study showed that BRET- and FA-based binding assays represent valuable alternatives to radioactivity-based methods for screening purposes and for a precise characterization of binding kinetics supporting the exploration of binding mechanisms.
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12
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Grätz L, Tropmann K, Bresinsky M, Müller C, Bernhardt G, Pockes S. NanoBRET binding assay for histamine H 2 receptor ligands using live recombinant HEK293T cells. Sci Rep 2020; 10:13288. [PMID: 32764682 PMCID: PMC7414126 DOI: 10.1038/s41598-020-70332-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Accepted: 07/24/2020] [Indexed: 01/12/2023] Open
Abstract
Fluorescence/luminescence-based techniques play an increasingly important role in the development of test systems for the characterization of future drug candidates, especially in terms of receptor binding in the field of G protein-coupled receptors (GPCRs). In this article, we present the establishment of a homogeneous live cell-based BRET binding assay for the histamine H2 receptor with different fluorescently labeled squaramide-type compounds synthesized in the course of this study. Py-1-labeled ligand 8 (UR-KAT478) was found to be most suitable in BRET saturation binding experiments with respect to receptor affinity (pKd = 7.35) and signal intensity. Real-time kinetic experiments showed a full association of 8 within approximately 30 min and a slow dissociation of the ligand from the receptor. Investigation of reference compounds in BRET-based competition binding with 8 yielded pKi values in agreement with radioligand binding data. This study shows that the BRET binding assay is a versatile test system for the characterization of putative new ligands at the histamine H2 receptor and represents a valuable fluorescence-based alternative to canonical binding assays.
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Affiliation(s)
- Lukas Grätz
- Institute of Pharmacy, University of Regensburg, Universitätsstraße 31, 93053, Regensburg, Germany
| | - Katharina Tropmann
- Institute of Pharmacy, University of Regensburg, Universitätsstraße 31, 93053, Regensburg, Germany
| | - Merlin Bresinsky
- Institute of Pharmacy, University of Regensburg, Universitätsstraße 31, 93053, Regensburg, Germany
| | - Christoph Müller
- Institute of Pharmacy, University of Regensburg, Universitätsstraße 31, 93053, Regensburg, Germany
| | - Günther Bernhardt
- Institute of Pharmacy, University of Regensburg, Universitätsstraße 31, 93053, Regensburg, Germany
| | - Steffen Pockes
- Institute of Pharmacy, University of Regensburg, Universitätsstraße 31, 93053, Regensburg, Germany.
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13
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Chen TY, Li X, Hung CH, Bahudhanapati H, Tan J, Kass DJ, Zhang Y. The relaxin family peptide receptor 1 (RXFP1): An emerging player in human health and disease. Mol Genet Genomic Med 2020; 8:e1194. [PMID: 32100955 PMCID: PMC7196478 DOI: 10.1002/mgg3.1194] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Accepted: 02/11/2020] [Indexed: 12/14/2022] Open
Abstract
Background Relaxin/relaxin family peptide receptor 1 (RXFP1) signaling is important for both normal physiology and disease. Strong preclinical evidence supports relaxin as a potent antifibrotic molecule. However, relaxin‐based therapy failed in clinical trial in patients with systemic sclerosis. We and others have discovered that aberrant expression of RXFP1 may contribute to the abnormal relaxin/RXFP1 signaling in different diseases. Reduced RXFP1 expression and alternative splicing transcripts with potential functional consequences have been observed in fibrotic tissues. A relative decrease in RXFP1 expression in fibrotic tissues—specifically lung and skin—may explain a potential insensitivity to relaxin. In addition, receptor dimerization also plays important roles in relaxin/RXFP1 signaling. Methods This review describes the tissue specific expression, characteristics of the splicing variants, and homo/heterodimerization of RXFP1 in both normal physiological function and human diseases. We discuss the potential implications of these molecular features for developing therapeutics to restore relaxin/RXFP1 signaling and to harness relaxin's potential antifibrotic effects. Results Relaxin/RXFP1 signaling is important in both normal physiology and in human diseases. Reduced expression of RXFP1 in fibrotic lung and skin tissues surrenders both relaxin/RXFP1 signaling and their responsiveness to exogenous relaxin treatments. Alternative splicing and receptor dimerization are also important in regulating relaxin/RXFP1 signaling. Conclusions Understanding the molecular mechanisms that drive aberrant expression of RXFP1 in disease and the functional roles of alternative splicing and receptor dimerization will provide insight into therapeutic targets that may restore the relaxin responsiveness of fibrotic tissues.
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Affiliation(s)
- Ting-Yun Chen
- Division of Pulmonary, Allergy and Critical Care Medicine and the Dorothy P. and Richard P. Simmons Center for Interstitial Lung Disease, University of Pittsburgh, Pittsburgh, PA, USA.,Institute of Allied Health Sciences, National Cheng Kung University, Tainan, Taiwan
| | - Xiaoyun Li
- Division of Pulmonary, Allergy and Critical Care Medicine and the Dorothy P. and Richard P. Simmons Center for Interstitial Lung Disease, University of Pittsburgh, Pittsburgh, PA, USA
| | - Ching-Hsia Hung
- Institute of Allied Health Sciences, National Cheng Kung University, Tainan, Taiwan
| | - Harinath Bahudhanapati
- Division of Pulmonary, Allergy and Critical Care Medicine and the Dorothy P. and Richard P. Simmons Center for Interstitial Lung Disease, University of Pittsburgh, Pittsburgh, PA, USA
| | - Jiangning Tan
- Division of Pulmonary, Allergy and Critical Care Medicine and the Dorothy P. and Richard P. Simmons Center for Interstitial Lung Disease, University of Pittsburgh, Pittsburgh, PA, USA
| | - Daniel J Kass
- Division of Pulmonary, Allergy and Critical Care Medicine and the Dorothy P. and Richard P. Simmons Center for Interstitial Lung Disease, University of Pittsburgh, Pittsburgh, PA, USA
| | - Yingze Zhang
- Division of Pulmonary, Allergy and Critical Care Medicine and the Dorothy P. and Richard P. Simmons Center for Interstitial Lung Disease, University of Pittsburgh, Pittsburgh, PA, USA.,Department of Human Genetics, University of Pittsburgh, Pittsburgh, PA, USA
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14
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Soave M, Briddon SJ, Hill SJ, Stoddart LA. Fluorescent ligands: Bringing light to emerging GPCR paradigms. Br J Pharmacol 2020; 177:978-991. [PMID: 31877233 DOI: 10.1111/bph.14953] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2019] [Revised: 11/19/2019] [Accepted: 12/05/2019] [Indexed: 01/07/2023] Open
Abstract
In recent years, several novel aspects of GPCR pharmacology have been described, which are thought to play a role in determining the in vivo efficacy of a compound. Fluorescent ligands have been used to study many of these, which have also required the development of new experimental approaches. Fluorescent ligands offer the potential to use the same fluorescent probe to perform a broad range of experiments, from single-molecule microscopy to in vivo BRET. This review provides an overview of the in vitro use of fluorescent ligands in further understanding emerging pharmacological paradigms within the GPCR field, including ligand-binding kinetics, allosterism and intracellular signalling, along with the use of fluorescent ligands to study physiologically relevant therapeutic agents.
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Affiliation(s)
- Mark Soave
- Cell Signalling and Pharmacology Research Group, Division of Physiology, Pharmacology and Neuroscience, School of Life Sciences, University of Nottingham, Nottingham, UK.,Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham and University of Nottingham, Midlands, UK
| | - Stephen J Briddon
- Cell Signalling and Pharmacology Research Group, Division of Physiology, Pharmacology and Neuroscience, School of Life Sciences, University of Nottingham, Nottingham, UK.,Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham and University of Nottingham, Midlands, UK
| | - Stephen J Hill
- Cell Signalling and Pharmacology Research Group, Division of Physiology, Pharmacology and Neuroscience, School of Life Sciences, University of Nottingham, Nottingham, UK.,Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham and University of Nottingham, Midlands, UK
| | - Leigh A Stoddart
- Cell Signalling and Pharmacology Research Group, Division of Physiology, Pharmacology and Neuroscience, School of Life Sciences, University of Nottingham, Nottingham, UK.,Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham and University of Nottingham, Midlands, UK
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15
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Hoare BL, Kocan M, Bruell S, Scott DJ, Bathgate RAD. Using the novel HiBiT tag to label cell surface relaxin receptors for BRET proximity analysis. Pharmacol Res Perspect 2019; 7:e00513. [PMID: 31384473 PMCID: PMC6667744 DOI: 10.1002/prp2.513] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Revised: 07/11/2019] [Accepted: 07/16/2019] [Indexed: 12/04/2022] Open
Abstract
Relaxin family peptide 1 (RXFP1) is the receptor for relaxin a peptide hormone with important therapeutic potential. Like many G protein-coupled receptors (GPCRs), RXFP1 has been reported to form homodimers. Given the complex activation mechanism of RXFP1 by relaxin, we wondered whether homodimerization may be explicitly required for receptor activation, and therefore sought to determine if there is any relaxin-dependent change in RXFP1 proximity at the cell surface. Bioluminescence resonance energy transfer (BRET) between recombinantly tagged receptors is often used in GPCR proximity studies. RXFP1 targets poorly to the cell surface when overexpressed in cell lines, with the majority of the receptor proteins sequestered within the cell. Thus, any relaxin-induced changes in RXFP1 proximity at the cell surface may be obscured by BRET signal originating from intracellular compartments. We therefore, utilized the newly developed split luciferase system called HiBiT to specifically label the extracellular terminus of cell surface RXFP1 receptors in combination with mCitrine-tagged receptors, using the GABAB heterodimer as a positive control. This demonstrated that the BRET signal detected from RXFP1-RXFP1 proximity at the cell surface does not appear to be due to stable physical interactions. The fact that there is also no relaxin-mediated change in RXFP1-RXFP1 proximity at the cell surface further supports these conclusions. This work provides a basis by which cell surface GPCR proximity and expression levels can be specifically studied using a facile and homogeneous labeling technique such as HiBiT.
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Affiliation(s)
- Bradley L. Hoare
- Florey Institute of Neuroscience and Mental Health and Florey Department of Neuroscience and Mental HealthParkvilleVictoriaAustralia
| | - Martina Kocan
- Florey Institute of Neuroscience and Mental Health and Florey Department of Neuroscience and Mental HealthParkvilleVictoriaAustralia
| | - Shoni Bruell
- Florey Institute of Neuroscience and Mental Health and Florey Department of Neuroscience and Mental HealthParkvilleVictoriaAustralia
- Department of Biochemistry and Molecular BiologyThe University of MelbourneParkvilleVictoriaAustralia
| | - Daniel J. Scott
- Florey Institute of Neuroscience and Mental Health and Florey Department of Neuroscience and Mental HealthParkvilleVictoriaAustralia
- Department of Biochemistry and Molecular BiologyThe University of MelbourneParkvilleVictoriaAustralia
| | - Ross A. D. Bathgate
- Florey Institute of Neuroscience and Mental Health and Florey Department of Neuroscience and Mental HealthParkvilleVictoriaAustralia
- Department of Biochemistry and Molecular BiologyThe University of MelbourneParkvilleVictoriaAustralia
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16
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Red-shifted bioluminescence Resonance Energy Transfer: Improved tools and materials for analytical in vivo approaches. Trends Analyt Chem 2019. [DOI: 10.1016/j.trac.2019.04.011] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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17
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Dale NC, Johnstone EKM, White CW, Pfleger KDG. NanoBRET: The Bright Future of Proximity-Based Assays. Front Bioeng Biotechnol 2019; 7:56. [PMID: 30972335 PMCID: PMC6443706 DOI: 10.3389/fbioe.2019.00056] [Citation(s) in RCA: 97] [Impact Index Per Article: 19.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2019] [Accepted: 03/04/2019] [Indexed: 12/17/2022] Open
Abstract
Bioluminescence resonance energy transfer (BRET) is a biophysical technique used to monitor proximity within live cells. BRET exploits the naturally occurring phenomenon of dipole-dipole energy transfer from a donor enzyme (luciferase) to an acceptor fluorophore following enzyme-mediated oxidation of a substrate. This results in production of a quantifiable signal that denotes proximity between proteins and/or molecules tagged with complementary luciferase and fluorophore partners. BRET assays have been used to observe an array of biological functions including ligand binding, intracellular signaling, receptor-receptor proximity, and receptor trafficking, however, BRET assays can theoretically be used to monitor the proximity of any protein or molecule for which appropriate fusion constructs and/or fluorophore conjugates can be produced. Over the years, new luciferases and approaches have been developed that have increased the potential applications for BRET assays. In particular, the development of the small, bright and stable Nanoluciferase (NanoLuc; Nluc) and its use in NanoBRET has vastly broadened the potential applications of BRET assays. These advances have exciting potential to produce new experimental methods to monitor protein-protein interactions (PPIs), protein-ligand interactions, and/or molecular proximity. In addition to NanoBRET, Nluc has also been exploited to produce NanoBiT technology, which further broadens the scope of BRET to monitor biological function when NanoBiT is combined with an acceptor. BRET has proved to be a powerful tool for monitoring proximity and interaction, and these recent advances further strengthen its utility for a range of applications.
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Affiliation(s)
- Natasha C Dale
- Molecular Endocrinology and Pharmacology, Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands, WA, Australia.,Centre for Medical Research, The University of Western Australia, Crawley, WA, Australia.,Australian Research Council Centre for Personalised Therapeutics TechnologiesAustralia
| | - Elizabeth K M Johnstone
- Molecular Endocrinology and Pharmacology, Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands, WA, Australia.,Centre for Medical Research, The University of Western Australia, Crawley, WA, Australia.,Australian Research Council Centre for Personalised Therapeutics TechnologiesAustralia
| | - Carl W White
- Molecular Endocrinology and Pharmacology, Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands, WA, Australia.,Centre for Medical Research, The University of Western Australia, Crawley, WA, Australia.,Australian Research Council Centre for Personalised Therapeutics TechnologiesAustralia
| | - Kevin D G Pfleger
- Molecular Endocrinology and Pharmacology, Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands, WA, Australia.,Centre for Medical Research, The University of Western Australia, Crawley, WA, Australia.,Australian Research Council Centre for Personalised Therapeutics TechnologiesAustralia.,Dimerix Limited, Nedlands, WA, Australia
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