2
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Alexander TI, Tasma Z, Siow A, Rees TA, Brimble MA, Harris PWR, Hay DL, Walker CS. Novel Fluorescently Labeled PACAP and VIP Highlight Differences between Peptide Internalization and Receptor Pharmacology. ACS Pharmacol Transl Sci 2022; 6:52-64. [PMID: 36654758 PMCID: PMC9841777 DOI: 10.1021/acsptsci.2c00124] [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: 06/26/2022] [Indexed: 12/13/2022]
Abstract
The related peptides pituitary adenylate cyclase-activating polypeptide (PACAP) and vasoactive intestinal peptide (VIP) have diverse biological functions in peripheral tissues and the central nervous system. Therefore, these peptides and their three receptors represent potential drug targets for several conditions, including neurological and pain-related disorders. However, very little is known about how these peptides regulate their receptors through processes such as internalization. Therefore, we developed tools to study receptor regulation through the synthesis of fluorescently labeled analogues of PACAP-38, PACAP-27, and VIP using copper-mediated 1,3-dipolar cycloaddition of the Cy5 fluorophore. The functionality of Cy5-labeled peptides at their receptors was confirmed in cAMP accumulation assays. Internalization of the Cy5-labeled peptides was then examined and quantified at two distinct PAC1 receptor splice variants, VPAC1 and VPAC2 receptors in transfected cells. All labeled peptides were functional, exhibiting comparable cAMP pharmacology to their unlabeled counterparts and underwent internalization in a time-dependent manner. Temporal differences in the internalization profiles were observed between Cy5-labeled peptides at the PAC1n, PAC1s, VPAC1, and VPAC2 receptors. Interestingly, the pattern of Cy5-labeled peptide activity differed for cAMP accumulation and internalization, indicating that these peptides differentially stimulate cAMP accumulation and internalization and therefore display biased agonism. This novel insight into PACAP-responsive receptor signaling and internalization may provide a unique avenue for future therapeutic development. The fluorescently labeled PACAP and VIP peptides described herein, which we validated as tools to study receptor internalization, will have utility across a broad range of applications and provide greater insight into this receptor family.
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Affiliation(s)
- Tyla I. Alexander
- Department
of Pharmacology and Toxicology, The University
of Otago, Dunedin 9054, New Zealand,Maurice
Wilkins Centre for Molecular Biodiscovery, The University of Auckland, Auckland 1010, New Zealand
| | - Zoe Tasma
- Maurice
Wilkins Centre for Molecular Biodiscovery, The University of Auckland, Auckland 1010, New Zealand,School
of Biological Sciences, The University of
Auckland, Auckland 1010, New Zealand
| | - Andrew Siow
- School
of Chemical Sciences, The University of
Auckland, Auckland 1010, New Zealand
| | - Tayla A. Rees
- Maurice
Wilkins Centre for Molecular Biodiscovery, The University of Auckland, Auckland 1010, New Zealand,School
of Biological Sciences, The University of
Auckland, Auckland 1010, New Zealand
| | - Margaret A. Brimble
- Maurice
Wilkins Centre for Molecular Biodiscovery, The University of Auckland, Auckland 1010, New Zealand,School
of Chemical Sciences, The University of
Auckland, Auckland 1010, New Zealand
| | - Paul W. R. Harris
- Maurice
Wilkins Centre for Molecular Biodiscovery, The University of Auckland, Auckland 1010, New Zealand,School
of Chemical Sciences, The University of
Auckland, Auckland 1010, New Zealand
| | - Debbie L. Hay
- Department
of Pharmacology and Toxicology, The University
of Otago, Dunedin 9054, New Zealand,Maurice
Wilkins Centre for Molecular Biodiscovery, The University of Auckland, Auckland 1010, New Zealand
| | - Christopher S. Walker
- Maurice
Wilkins Centre for Molecular Biodiscovery, The University of Auckland, Auckland 1010, New Zealand,School
of Biological Sciences, The University of
Auckland, Auckland 1010, New Zealand,
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3
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Gbahou F, Levin S, Tikhonova IG, Somalo Barranco G, Izabelle C, Ohana RF, Jockers R. Luminogenic HiBiT Peptide-Based NanoBRET Ligand Binding Assays for Melatonin Receptors. ACS Pharmacol Transl Sci 2022; 5:668-678. [DOI: 10.1021/acsptsci.2c00096] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2022] [Indexed: 11/28/2022]
Affiliation(s)
- Florence Gbahou
- Université Paris Cité, Institut Cochin, INSERM, CNRS, 75014 Paris, France
| | - Sergiy Levin
- Promega Corporation, Fitchburg, Wisconsin 53711, United States
| | - Irina G. Tikhonova
- School of Pharmacy, Medical Biology Centre, Queen’s University Belfast, Belfast BT9 7BL, United Kingdom
| | | | - Charlotte Izabelle
- Université Paris Cité, Institut Cochin, INSERM, CNRS, 75014 Paris, France
| | | | - Ralf Jockers
- Université Paris Cité, Institut Cochin, INSERM, CNRS, 75014 Paris, France
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4
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The use of fluorescence correlation spectroscopy to characterise the molecular mobility of G protein-coupled receptors in membrane microdomains: an update. Biochem Soc Trans 2021; 49:1547-1554. [PMID: 34436556 DOI: 10.1042/bst20201001] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2021] [Revised: 07/26/2021] [Accepted: 07/28/2021] [Indexed: 12/24/2022]
Abstract
It has become increasingly apparent that some G protein-coupled receptors (GPCRs) are not homogeneously expressed within the plasma membrane but may instead be organised within distinct signalling microdomains. These microdomains localise GPCRs in close proximity with other membrane proteins and intracellular signalling partners and could have profound implications for the spatial and temporal control of downstream signalling. In order to probe the molecular mechanisms that govern GPCR pharmacology within these domains, fluorescence techniques with effective single receptor sensitivity are required. Of these, fluorescence correlation spectroscopy (FCS) is a technique that meets this sensitivity threshold. This short review will provide an update of the recent uses of FCS based techniques in conjunction with GPCR subtype selective fluorescent ligands to characterise dynamic ligand-receptor interactions in whole cells and using purified GPCRs.
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5
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Roberts MJ, May LT, Keen AC, Liu B, Lam T, Charlton SJ, Rosethorne EM, Halls ML. Inhibition of the Proliferation of Human Lung Fibroblasts by Prostacyclin Receptor Agonists is Linked to a Sustained cAMP Signal in the Nucleus. Front Pharmacol 2021; 12:669227. [PMID: 33995100 PMCID: PMC8116805 DOI: 10.3389/fphar.2021.669227] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Accepted: 04/16/2021] [Indexed: 12/21/2022] Open
Abstract
Idiopathic pulmonary fibrosis is a chronic and progressive fibrotic lung disease, and current treatments are limited by their side effects. Proliferation of human lung fibroblasts in the pulmonary interstitial tissue is a hallmark of this disease and is driven by prolonged ERK signalling in the nucleus in response to growth factors such as platelet-derived growth factor (PDGF). Agents that increase cAMP have been suggested as alternative therapies, as this second messenger can inhibit the ERK cascade. We previously examined a panel of eight Gαs-cAMP-coupled G protein-coupled receptors (GPCRs) endogenously expressed in human lung fibroblasts. Although the cAMP response was important for the anti-fibrotic effects of GPCR agonists, the magnitude of the acute cAMP response was not predictive of anti-fibrotic efficacy. Here we examined the reason for this apparent disconnect by stimulating the Gαs-coupled prostacyclin receptor and measuring downstream signalling at a sub-cellular level. MRE-269 and treprostinil caused sustained cAMP signalling in the nucleus and complete inhibition of PDGF-induced nuclear ERK and fibroblast proliferation. In contrast, iloprost caused a transient increase in nuclear cAMP, there was no effect of iloprost on PDGF-induced ERK in the nucleus, and this agonist was much less effective at reversing PDGF-induced proliferation. This suggests that sustained elevation of cAMP in the nucleus is necessary for efficient inhibition of PDGF-induced nuclear ERK and fibroblast proliferation. This is an important first step towards understanding of the signalling events that drive GPCR inhibition of fibrosis.
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Affiliation(s)
- Maxine J Roberts
- Cell Signalling Research Group, School of Life Sciences, University of Nottingham, Queen's Medical Centre, Nottingham, United Kingdom.,Drug Discovery Biology Theme, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Vic, Australia
| | - Lauren T May
- Drug Discovery Biology Theme, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Vic, Australia
| | - Alastair C Keen
- Drug Discovery Biology Theme, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Vic, Australia
| | - Bonan Liu
- Drug Discovery Biology Theme, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Vic, Australia
| | - Terrance Lam
- Drug Discovery Biology Theme, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Vic, Australia
| | - Steven J Charlton
- Cell Signalling Research Group, School of Life Sciences, University of Nottingham, Queen's Medical Centre, Nottingham, United Kingdom.,Excellerate Bioscience Ltd., BioCity, Nottingham, United Kingdom
| | - Elizabeth M Rosethorne
- Cell Signalling Research Group, School of Life Sciences, University of Nottingham, Queen's Medical Centre, Nottingham, United Kingdom
| | - Michelle L Halls
- Drug Discovery Biology Theme, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Vic, Australia
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