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Nguyen DM, Rath DH, Devost D, Pétrin D, Rizk R, Ji AX, Narayanan N, Yong D, Zhai A, Kuntz DA, Mian MUQ, Pomroy NC, Keszei AFA, Benlekbir S, Mazhab-Jafari MT, Rubinstein JL, Hébert TE, Privé GG. Structure and dynamics of a pentameric KCTD5/CUL3/Gβγ E3 ubiquitin ligase complex. Proc Natl Acad Sci U S A 2024; 121:e2315018121. [PMID: 38625940 PMCID: PMC11047111 DOI: 10.1073/pnas.2315018121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2023] [Accepted: 03/07/2024] [Indexed: 04/18/2024] Open
Abstract
Heterotrimeric G proteins can be regulated by posttranslational modifications, including ubiquitylation. KCTD5, a pentameric substrate receptor protein consisting of an N-terminal BTB domain and a C-terminal domain, engages CUL3 to form the central scaffold of a cullin-RING E3 ligase complex (CRL3KCTD5) that ubiquitylates Gβγ and reduces Gβγ protein levels in cells. The cryo-EM structure of a 5:5:5 KCTD5/CUL3NTD/Gβ1γ2 assembly reveals a highly dynamic complex with rotations of over 60° between the KCTD5BTB/CUL3NTD and KCTD5CTD/Gβγ moieties of the structure. CRL3KCTD5 engages the E3 ligase ARIH1 to ubiquitylate Gβγ in an E3-E3 superassembly, and extension of the structure to include full-length CUL3 with RBX1 and an ARIH1~ubiquitin conjugate reveals that some conformational states position the ARIH1~ubiquitin thioester bond to within 10 Å of lysine-23 of Gβ and likely represent priming complexes. Most previously described CRL/substrate structures have consisted of monovalent complexes and have involved flexible peptide substrates. The structure of the KCTD5/CUL3NTD/Gβγ complex shows that the oligomerization of a substrate receptor can generate a polyvalent E3 ligase complex and that the internal dynamics of the substrate receptor can position a structured target for ubiquitylation in a CRL3 complex.
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Affiliation(s)
- Duc Minh Nguyen
- Princess Margaret Cancer Centre, University Health Network, Toronto, ONM5G 1L7, Canada
- Department of Biochemistry, University of Toronto, Toronto, ONM5S 1A8, Canada
| | - Deanna H. Rath
- Princess Margaret Cancer Centre, University Health Network, Toronto, ONM5G 1L7, Canada
| | - Dominic Devost
- Department of Pharmacology and Therapeutics, McGill University, Montréal, QCH3G 1Y6, Canada
| | - Darlaine Pétrin
- Department of Pharmacology and Therapeutics, McGill University, Montréal, QCH3G 1Y6, Canada
| | - Robert Rizk
- Department of Pharmacology and Therapeutics, McGill University, Montréal, QCH3G 1Y6, Canada
| | - Alan X. Ji
- Princess Margaret Cancer Centre, University Health Network, Toronto, ONM5G 1L7, Canada
- Department of Biochemistry, University of Toronto, Toronto, ONM5S 1A8, Canada
| | - Naveen Narayanan
- Princess Margaret Cancer Centre, University Health Network, Toronto, ONM5G 1L7, Canada
| | - Darren Yong
- Princess Margaret Cancer Centre, University Health Network, Toronto, ONM5G 1L7, Canada
| | - Andrew Zhai
- Princess Margaret Cancer Centre, University Health Network, Toronto, ONM5G 1L7, Canada
| | - Douglas A. Kuntz
- Princess Margaret Cancer Centre, University Health Network, Toronto, ONM5G 1L7, Canada
| | - Maha U. Q. Mian
- Princess Margaret Cancer Centre, University Health Network, Toronto, ONM5G 1L7, Canada
| | - Neil C. Pomroy
- Princess Margaret Cancer Centre, University Health Network, Toronto, ONM5G 1L7, Canada
| | | | - Samir Benlekbir
- Molecular Medicine Program, The Hospital for Sick Children, Toronto, ONM5G 0A4, Canada
| | - Mohammad T. Mazhab-Jafari
- Princess Margaret Cancer Centre, University Health Network, Toronto, ONM5G 1L7, Canada
- Department of Medical Biophysics, University of Toronto, Toronto, ONM5G 2M9, Canada
| | - John L. Rubinstein
- Department of Biochemistry, University of Toronto, Toronto, ONM5S 1A8, Canada
- Molecular Medicine Program, The Hospital for Sick Children, Toronto, ONM5G 0A4, Canada
- Department of Medical Biophysics, University of Toronto, Toronto, ONM5G 2M9, Canada
| | - Terence E. Hébert
- Department of Pharmacology and Therapeutics, McGill University, Montréal, QCH3G 1Y6, Canada
| | - Gilbert G. Privé
- Princess Margaret Cancer Centre, University Health Network, Toronto, ONM5G 1L7, Canada
- Department of Biochemistry, University of Toronto, Toronto, ONM5S 1A8, Canada
- Department of Medical Biophysics, University of Toronto, Toronto, ONM5G 2M9, Canada
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Nassour H, Pétrin D, Devost D, Billard E, Sleno R, Hébert TE, Chatenet D. Evidence for heterodimerization and functional interaction of the urotensin II and the angiotensin II type 1 receptors. Cell Signal 2024; 116:111056. [PMID: 38262555 DOI: 10.1016/j.cellsig.2024.111056] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2024] [Accepted: 01/15/2024] [Indexed: 01/25/2024]
Abstract
Despite the observation of synergistic interactions between the urotensinergic and angiotensinergic systems, the interplay between the urotensin II receptor (hUT) and the angiotensin II type 1 receptor (hAT1R) in regulating cellular signaling remains incompletely understood. Notably, the putative interaction between hUT and hAT1R could engender reciprocal allosteric modulation of their signaling signatures, defining a unique role for these complexes in cardiovascular physiology and pathophysiology. Using a combination of co-immunoprecipitation, bioluminescence resonance energy transfer (BRET) and FlAsH BRET-based conformational biosensors, we first demonstrated the physical interaction between hUT and hAT1R. Next, to analyze how this functional interaction regulated proximal and distal hUT- and hAT1R-associated signaling pathways, we used BRET-based signaling biosensors and western blots to profile pathway-specific signaling in HEK 293 cells expressing hUT, hAT1R or both. We observed that hUT-hAT1R heterodimers triggered distinct signaling outcomes compared to their respective parent receptors alone. Notably, co-transfection of hUT and hAT1R has no impact on hUII-induced Gq activation but significantly reduced the potency and efficacy of Ang II to mediate Gq activation. Interestingly, URP, the second hUT endogenous ligand, produce a distinct signaling signature compared to hUII at hUT-hAT1R. Our results therefore suggest that assembly of hUT with hAT1R might be important for allosteric modulation of outcomes associated with specific hardwired signaling complexes in healthy and disease states. Altogether, our work, which potentially explains the interplay observed in native cells and tissues, validates such complexes as potential targets to promote the design of compounds that can modulate heterodimer function selectively.
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Affiliation(s)
- Hassan Nassour
- Institut National de la Recherche Scientifique, Centre Armand-Frappier Santé Biotechnologie, Université du Québec, Ville de Laval, QC, Canada
| | - Darlaine Pétrin
- Department of Pharmacology and Therapeutics, McGill University, Montréal, Canada
| | - Dominic Devost
- Department of Pharmacology and Therapeutics, McGill University, Montréal, Canada
| | - Etienne Billard
- Department of Pharmacology and Therapeutics, McGill University, Montréal, Canada
| | - Rory Sleno
- Department of Pharmacology and Therapeutics, McGill University, Montréal, Canada
| | - Terence E Hébert
- Department of Pharmacology and Therapeutics, McGill University, Montréal, Canada.
| | - David Chatenet
- Institut National de la Recherche Scientifique, Centre Armand-Frappier Santé Biotechnologie, Université du Québec, Ville de Laval, QC, Canada.
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Privé G, Nguyen DM, Ji A, Yong D, Zhai A, Pomroy N, Kuntz D, Petrain D, Devost D, Hebert T. Cryo-EM structure of a multivalent ubiquitin ligase complex. Acta Crystallogr A Found Adv 2022. [DOI: 10.1107/s2053273322098370] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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Toufaily C, Fortin J, Alonso CA, Lapointe E, Zhou X, Santiago-Andres Y, Lin YF, Cui Y, Wang Y, Devost D, Roelfsema F, Steyn F, Hanyaloglu AC, Hébert TE, Fiordelisio T, Boerboom D, Bernard DJ. Addition of a carboxy terminal tail to the normally tailless gonadotropin-releasing hormone receptor impairs fertility in female mice. eLife 2021; 10:72937. [PMID: 34939930 PMCID: PMC8741216 DOI: 10.7554/elife.72937] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Accepted: 12/06/2021] [Indexed: 11/13/2022] Open
Abstract
Gonadotropin-releasing hormone (GnRH) is the primary neuropeptide controlling reproduction in vertebrates. GnRH stimulates follicle-stimulating hormone (FSH) and luteinizing hormone (LH) synthesis via a G-protein-coupled receptor, GnRHR, in the pituitary gland. In mammals, GnRHR lacks a C-terminal cytosolic tail (Ctail) and does not exhibit homologous desensitization. This might be an evolutionary adaptation that enables LH surge generation and ovulation. To test this idea, we fused the chicken GnRHR Ctail to the endogenous murine GnRHR in a transgenic model. The LH surge was blunted, but not blocked in these mice. In contrast, they showed reductions in FSH production, ovarian follicle development, and fertility. Addition of the Ctail altered the nature of agonist-induced calcium signaling required for normal FSH production. The loss of the GnRHR Ctail during mammalian evolution is unlikely to have conferred a selective advantage by enabling the LH surge. The adaptive significance of this specialization remains to be determined.
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Affiliation(s)
- Chirine Toufaily
- Department of Pharmacology and Therapeutics, McGill University, Montreal, Canada
| | - Jérôme Fortin
- Department of Pharmacology and Therapeutics, McGill University, Montreal, Canada
| | - Carlos Ai Alonso
- Department of Pharmacology and Therapeutics, McGill University, Montreal, Canada
| | - Evelyne Lapointe
- Département de biomédecine vétérinaire, Universite de Montreal, Ste-Hyacinthe, Canada
| | - Xiang Zhou
- Department of Pharmacology and Therapeutics, McGill University, Montreal, Canada
| | - Yorgui Santiago-Andres
- Departamento de Ecología y Recursos Naturales, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Yeu-Farn Lin
- Department of Pharmacology and Therapeutics, McGill University, Montreal, Canada
| | - Yiming Cui
- Department of Pharmacology and Therapeutics, McGill University, Montreal, Canada
| | - Ying Wang
- Department of Pharmacology and Therapeutics, McGill University, Montreal, Canada
| | - Dominic Devost
- Department of Pharmacology and Therapeutics, McGill University, Montreal, Canada
| | - Ferdinand Roelfsema
- Department of Internal Medicine, Leiden University Medical Center, Leiden, Netherlands
| | - Frederik Steyn
- School of Biomedical Sciences, The University of Queensland, Brisbane, Australia
| | - Aylin C Hanyaloglu
- Department of Metabolism, Digestion and Reproduction, Imperial College London, London, United Kingdom
| | - Terence E Hébert
- Department of Pharmacology and Therapeutics, McGill University, Montreal, Canada
| | - Tatiana Fiordelisio
- 3epartamento de Ecología y Recursos Naturales, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Derek Boerboom
- Département de biomédecine vétérinaire, Universite de Montreal, Ste-Hyacinthe, Canada
| | - Daniel J Bernard
- Department of Pharmacology and Therapeutics, McGill University, Montreal, Canada
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Devost D, Zingg HH, Hébert TE. The MAP kinase ERK5/MAPK7 is a downstream effector of oxytocin signaling in myometrial cells. Cell Signal 2021; 90:110211. [PMID: 34902542 DOI: 10.1016/j.cellsig.2021.110211] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2021] [Revised: 12/02/2021] [Accepted: 12/04/2021] [Indexed: 12/14/2022]
Abstract
The hormone oxytocin (OT) has pleiotropic activities both in the central nervous system as well as in peripheral tissues, including uterotonic effects on the myometrium during parturition. OT effects are mediated by a single transmembrane receptor, belonging to the GPCR (G protein-coupled receptor) superfamily and coupled primarily to Gq- and Gi-containing heterotrimeric G proteins. Upon receptor stimulation, one well-studied downstream effect is activation of the ERK1/2 MAP (mitogen-activated protein) kinase, and studies have shown that induction of COX-2 by OT in the myometrium required ERK1/2 activity. Many studies investigating the role of ERK1/2 in myometrial tissue were based on the use of chemical inhibitors that, to varying degrees, also inhibited ERK5/MAPK7. Here we report that OT activates ERK5 in a human myometrial cell line in a dose- and time-dependent manner through the activation of Gi/o heterotrimers. Using complementary approaches, we demonstrate that OT-induced COX-2 induction and the concomitant release of PGF2α into the media are primarily ERK5-dependent and to a much lesser extent ERK1/2-dependent. Moreover, in contrast to ERK1/2 activation, ERK5 activation is downstream of Gi/o activation. Here, we also found that ERK5 impacted both basal and to a lesser extent, OT-mediated myometrial cell contraction in vitro. Finally, tracking both ERK1/2 and ERK5 activity during different stages of gestation in rat myometrium, we showed that they followed distinct patterns starting at the onset of labor corresponding to the highest COX-2 expression levels. Overall, our results reveal an important, hitherto unrecognized role for ERK5 in myometrial cell contraction involving induction of COX-2. This novel pathway is likely to play an important role in supporting uterine contractions during parturition.
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Affiliation(s)
- Dominic Devost
- Department of Pharmacology and Therapeutics, McGill University, Montreal, Québec H3G 1Y6, Canada.
| | - Hans H Zingg
- Department of Pharmacology and Therapeutics, McGill University, Montreal, Québec H3G 1Y6, Canada
| | - Terence E Hébert
- Department of Pharmacology and Therapeutics, McGill University, Montreal, Québec H3G 1Y6, Canada.
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O'Brien SL, Johnstone EKM, Devost D, Conroy J, Reichelt ME, Purdue BW, Ayoub MA, Kawai T, Inoue A, Eguchi S, Hébert TE, Pfleger KDG, Thomas WG. Corrigendum to "BRET-based assay to monitor EGFR transactivation by the AT1R reveals Gq/11 protein-independent activation and AT1R-EGFR complexes" [Biochem. Pharmacol. 158 (2108) 232-242]. Biochem Pharmacol 2021; 192:114756. [PMID: 34509100 DOI: 10.1016/j.bcp.2021.114756] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Shannon L O'Brien
- Receptor Biology Group, The School of Biomedical Sciences, Faculty of Medicine, The University of Queensland, St Lucia 4072, Queensland, Australia
| | - Elizabeth K M Johnstone
- Molecular Endocrinology and Pharmacology, Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands and Centre for Medical Research, The University of Western Australia, Crawley, Western Australia 6009, Australia
| | - Dominic Devost
- Department of Pharmacology and Therapeutics, McGill University, Montreal, QC, Canada
| | - Jacinta Conroy
- Receptor Biology Group, The School of Biomedical Sciences, Faculty of Medicine, The University of Queensland, St Lucia 4072, Queensland, Australia
| | - Melissa E Reichelt
- Receptor Biology Group, The School of Biomedical Sciences, Faculty of Medicine, The University of Queensland, St Lucia 4072, Queensland, Australia
| | - Brooke W Purdue
- Receptor Biology Group, The School of Biomedical Sciences, Faculty of Medicine, The University of Queensland, St Lucia 4072, Queensland, Australia
| | - Mohammed A Ayoub
- Molecular Endocrinology and Pharmacology, Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands and Centre for Medical Research, The University of Western Australia, Crawley, Western Australia 6009, Australia
| | - Tatsuo Kawai
- Cardiovascular Research Centre, Department of Physiology, Lewis Katz School of Medicine at Temple University, Philadelphia, PA, United States
| | - Asuka Inoue
- Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Miyagi 980-8578, Japan
| | - Satoru Eguchi
- Cardiovascular Research Centre, Department of Physiology, Lewis Katz School of Medicine at Temple University, Philadelphia, PA, United States
| | - Terence E Hébert
- Department of Pharmacology and Therapeutics, McGill University, Montreal, QC, Canada
| | - Kevin D G Pfleger
- Molecular Endocrinology and Pharmacology, Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands and Centre for Medical Research, The University of Western Australia, Crawley, Western Australia 6009, Australia; Dimerix Limited, Nedlands, Western Australia 6009, Australia
| | - Walter G Thomas
- Receptor Biology Group, The School of Biomedical Sciences, Faculty of Medicine, The University of Queensland, St Lucia 4072, Queensland, Australia; Centre for Cardiac and Vasculature Biology, The University of Queensland, St Lucia 4072, Queensland, Australia.
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Poujol de Molliens M, Jamadagni P, Létourneau M, Devost D, Hébert TE, Patten SA, Fournier A, Chatenet D. Design and biological assessment of membrane-tethering neuroprotective peptides derived from the pituitary adenylate cyclase-activating polypeptide type 1 receptor. Biochim Biophys Acta Gen Subj 2019; 1863:129398. [PMID: 31306709 DOI: 10.1016/j.bbagen.2019.07.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2019] [Revised: 07/03/2019] [Accepted: 07/10/2019] [Indexed: 12/13/2022]
Abstract
BACKGROUND The pituitary adenylate cyclase-activating polypeptide (PACAP) type 1 receptor (PAC1), a class B G protein-coupled receptor (GPCR), has emerged as a promising target for treating neurodegenerative conditions. Unfortunately, despite years of research, no PAC1-specific agonist has been discovered, as activity on two other GPCRs, VPAC1 and VPAC2, is retained with current analogs. Cell signaling is related to structural modifications in the intracellular loops (ICLs) of GPCRs. Thus, we hypothesized that peptides derived from the ICLs (called pepducins) of PAC1 might initiate, as allosteric ligands, signaling cascades after recognition of the parent receptor and modulation of its conformational landscape. METHODS Three pepducins were synthesized and evaluated for their ability to 1) promote cell survival; 2) stimulate various signaling pathways associated with PAC1 activation; 3) modulate selectively PAC1, VPAC1 or VPAC2 activation; and 4) sustain mobility and prevent death of dopaminergic neurons in a zebrafish model of neurodegeneration. RESULTS Assays demonstrated that these molecules promote SH-SY5Y cell survival, a human neuroblastoma cell line expressing PAC1, and activate signaling via Gαs and Gαq, with distinct potencies and efficacies. Also, PAC1-Pep1 and PAC1-Pep2 activated selectively PAC1-mediated Gαs stimulation. Finally, experiments, using a zebrafish neurodegeneration model, showed a neuroprotective action with all three pepducins and in particular, revealed the ability of PAC1-Pep1 and PAC1-Pep3 to preserve fish mobility and tyrosine hydroxylase expression in the brain. CONCLUSION We have developed the first neuroprotective pepducins derived from PAC1, a class B GPCR. GENERAL SIGNIFICANCE PAC1-derived pepducins represent attractive templates for the development of innovative neuroprotecting molecules.
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Affiliation(s)
- Mathilde Poujol de Molliens
- Institut National de la Recherche Scientifique, Centre Armand-Frappier, Groupe de Recherche en Ingénierie des Peptides et en Pharmacothérapie (GRIPP), Université du Québec, Ville de Laval, QC, Canada; Institut National de la Recherche Scientifique, Centre Armand-Frappier, Laboratoire d'études moléculaires et pharmacologiques des peptides (LEMPP), Université du Québec, Ville de Laval, QC, Canada
| | - Priyanka Jamadagni
- Institut National de la Recherche Scientifique, Centre Armand-Frappier, Université du Québec, Ville de Laval, QC, Canada
| | - Myriam Létourneau
- Institut National de la Recherche Scientifique, Centre Armand-Frappier, Groupe de Recherche en Ingénierie des Peptides et en Pharmacothérapie (GRIPP), Université du Québec, Ville de Laval, QC, Canada; Institut National de la Recherche Scientifique, Centre Armand-Frappier, Laboratoire d'études moléculaires et pharmacologiques des peptides (LEMPP), Université du Québec, Ville de Laval, QC, Canada
| | - Dominic Devost
- Department of Pharmacology and Therapeutics, McGill University, Montréal, QC, Canada
| | - Terence E Hébert
- Department of Pharmacology and Therapeutics, McGill University, Montréal, QC, Canada
| | - Shunmoogum A Patten
- Institut National de la Recherche Scientifique, Centre Armand-Frappier, Université du Québec, Ville de Laval, QC, Canada
| | - Alain Fournier
- Institut National de la Recherche Scientifique, Centre Armand-Frappier, Laboratoire d'études moléculaires et pharmacologiques des peptides (LEMPP), Université du Québec, Ville de Laval, QC, Canada
| | - David Chatenet
- Institut National de la Recherche Scientifique, Centre Armand-Frappier, Groupe de Recherche en Ingénierie des Peptides et en Pharmacothérapie (GRIPP), Université du Québec, Ville de Laval, QC, Canada.
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Bourque K, Devost D, Pétrin D, Hébert T. SAT-033 Studying Cell-Context Specific Effects on the Function of the AT1R in iPSCs and Their Differentiated Derivatives. J Endocr Soc 2019. [PMCID: PMC6552636 DOI: 10.1210/js.2019-sat-033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Cardiovascular homeostasis is tightly regulated by numerous neurohormonal mediators such as the renin-angiotensin system which plays an important role in the maintenance of blood pressure. Central to this system is the peptide hormone angiotensin II (Ang II) whose signals are transduced via the AT1 receptor (AT1R), an important member of the superfamily of G protein-coupled receptors (GPCRs). Ang II binding results in receptor activation characterized by structural re-arrangements within the receptor structure and the subsequent activation of its cognate G protein partners. GPCRs are allosteric in nature and their biological activity is highly dependent on the cell context in which they are expressed1. Changes in the cellular background such as the differential availability of G proteins and effector molecules including putative dimer partners can affect receptor conformation and function. As such, we are interested in understanding how AT1R conformation and signaling are modulated by the cell context in which it is expressed1. In the past, studies that aimed at understanding signaling downstream of GPCRs mostly relied on heterologous expression systems such as HEK 293 cells because of their ease of culture. Such studies led to a ‘one size fits all’ notion that our findings could be reasonably extrapolated to guide drug discovery platforms relevant for human disease. However, it is clear that with the high rate of drug attrition, we need more physiologically relevant cellular models for studies of molecular signal transduction events to be translatable. With this in mind, we are generating iPSCs that stably express a panel of conformation-sensitive biosensors that reliably report on the conformational changes in the AT1R1,2. Our biosensors use resonance energy transfer between a bioluminescent donor and a fluorescent acceptor (FlAsH) where agonist-mediated conformational changes can be recorded1. Here, we will investigate how the conformation of the AT1R changes when expressed in AT1R-relevant cell types such as iPSC-derived cardiomyocytes and vascular smooth muscle cells. We will investigate how our conformational profiles differ in different iPSC-derived cell types in response to AT1R-specific agonists. Our goal is to gain a better mechanistic understanding of how cells are differentially wired leading to cell-specific conformational and signaling responses. We hope our results can guide rational drug design to better target the AT1R and other GPCRs. 1Devost D., et al (2017). Journal of Biological Chemistry, jbc-M116. 2Pei Y., et al (2015). Scientific reports, 5, 9205.
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Affiliation(s)
| | | | | | - Terence Hébert
- Pharmacology and Therapeutics, McGill University, Montreal, QC, Canada
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Fillion D, Devost D, Sleno R, Inoue A, Hébert TE. Asymmetric Recruitment of β-Arrestin1/2 by the Angiotensin II Type I and Prostaglandin F2α Receptor Dimer. Front Endocrinol (Lausanne) 2019; 10:162. [PMID: 30936850 PMCID: PMC6431625 DOI: 10.3389/fendo.2019.00162] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Accepted: 02/26/2019] [Indexed: 12/11/2022] Open
Abstract
Initially identified as monomers, G protein-coupled receptors (GPCRs) can also form functional homo- and heterodimers that act as distinct signaling hubs for cellular signal integration. We previously found that the angiotensin II (Ang II) type 1 receptor (AT1R) and the prostaglandin F2α (PGF2α) receptor (FP), both important in the control of smooth muscle contractility, form such a functional heterodimeric complex in HEK 293 and vascular smooth muscle cells. Here, we hypothesize that both Ang II- and PGF2α-induced activation of the AT1R/FP dimer, or the parent receptors alone, differentially regulate signaling by distinct patterns of β-arrestin recruitment. Using BRET-based biosensors, we assessed the recruitment kinetics of β-arrestin1/2 to the AT1R/FP dimer, or the parent receptors alone, when stimulated by either Ang II or PGF2α. Using cell lines with CRISPR/Cas9-mediated gene deletion, we also examined the role of G proteins in such recruitment. We observed that Ang II induced a rapid, robust, and sustained recruitment of β-arrestin1/2 to AT1R and, to a lesser extent, the heterodimer, as expected, since AT1R is a strong recruiter of both β-arrestin subtypes. However, PGF2α did not induce such recruitment to FP alone, although it did when the AT1R is present as a heterodimer. β-arrestins were likely recruited to the AT1R partner of the dimer. Gαq, Gα11, Gα12, and Gα13 were all involved to some extent in PGF2α-induced β-arrestin1/2 recruitment to the dimer as their combined absence abrogated the response, and their separate re-expression was sufficient to partially restore it. Taken together, our data sheds light on a new mechanism whereby PGF2α specifically recruits and signals through β-arrestin but only in the context of the AT1R/FP dimer, suggesting that this may be a new allosteric signaling entity.
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Affiliation(s)
- Dany Fillion
- Department of Pharmacology and Therapeutics, McGill University, Montréal, QC, Canada
| | - Dominic Devost
- Department of Pharmacology and Therapeutics, McGill University, Montréal, QC, Canada
| | - Rory Sleno
- Department of Pharmacology and Therapeutics, McGill University, Montréal, QC, Canada
| | - Asuka Inoue
- Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Japan
- Japan Science and Technology Agency, Precursory Research for Embryonic Science and Technology, Kawaguchi, Japan
| | - Terence E. Hébert
- Department of Pharmacology and Therapeutics, McGill University, Montréal, QC, Canada
- *Correspondence: Terence E. Hébert
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Namkung Y, LeGouill C, Kumar S, Cao Y, Teixeira LB, Lukasheva V, Giubilaro J, Simões SC, Longpré JM, Devost D, Hébert TE, Piñeyro G, Leduc R, Costa-Neto CM, Bouvier M, Laporte SA. Functional selectivity profiling of the angiotensin II type 1 receptor using pathway-wide BRET signaling sensors. Sci Signal 2018; 11:11/559/eaat1631. [PMID: 30514808 DOI: 10.1126/scisignal.aat1631] [Citation(s) in RCA: 85] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
G protein-coupled receptors (GPCRs) are important therapeutic targets that exhibit functional selectivity (biased signaling), in which different ligands or receptor variants elicit distinct downstream signaling. Understanding all the signaling events and biases that contribute to both the beneficial and adverse effects of GPCR stimulation by given ligands is important for drug discovery. Here, we report the design, validation, and use of pathway-selective bioluminescence resonance energy transfer (BRET) biosensors that monitor the engagement and activation of signaling effectors downstream of G proteins, including protein kinase C (PKC), phospholipase C (PLC), p63RhoGEF, and Rho. Combined with G protein and β-arrestin BRET biosensors, our sensors enabled real-time monitoring of GPCR signaling at different levels in downstream pathways in both native and engineered cells. Profiling of the responses to 14 angiotensin II (AngII) type 1 receptor (AT1R) ligands enabled the clustering of compounds into different subfamilies of biased ligands and showed that, in addition to the previously reported functional selectivity between Gαq and β-arrestin, there are also biases among G protein subtypes. We also demonstrated that biases observed at the receptor and G protein levels propagated to downstream signaling pathways and that these biases could occur through the engagement of different G proteins to activate a common effector. We also used these tools to determine how naturally occurring AT1R variants affected signaling bias. This suite of BRET biosensors provides a useful resource for fingerprinting biased ligands and mutant receptors and for dissecting functional selectivity at various levels of GPCR signaling.
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Affiliation(s)
- Yoon Namkung
- Department of Medicine, Research Institute of the McGill University Health Center (RI-MUHC), McGill University, Montréal, QC H4A 3J1, Canada
| | - Christian LeGouill
- Department of Biochemistry and Molecular Medicine, Institute for Research in Immunology and Cancer (IRIC), Université de Montréal, Montréal, QC H3T 1J4, Canada
| | - Sahil Kumar
- Department of Medicine, Research Institute of the McGill University Health Center (RI-MUHC), McGill University, Montréal, QC H4A 3J1, Canada
| | - Yubo Cao
- Department of Pharmacology and Therapeutics, McGill University, Montréal, QC H3G 1Y6, Canada
| | - Larissa B Teixeira
- Department of Biochemistry and Molecular Medicine, Institute for Research in Immunology and Cancer (IRIC), Université de Montréal, Montréal, QC H3T 1J4, Canada.,Departamento de Bioquímica e Imunologia, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, São Paulo 14049-900, Brazil
| | - Viktoriya Lukasheva
- Department of Biochemistry and Molecular Medicine, Institute for Research in Immunology and Cancer (IRIC), Université de Montréal, Montréal, QC H3T 1J4, Canada
| | - Jenna Giubilaro
- Department of Pharmacology and Therapeutics, McGill University, Montréal, QC H3G 1Y6, Canada
| | - Sarah C Simões
- Departamento de Bioquímica e Imunologia, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, São Paulo 14049-900, Brazil
| | - Jean-Michel Longpré
- Institut de Pharmacologie de Sherbrooke and Department of Pharmacology-Physiology, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, QC J1H 5N4, Canada
| | - Dominic Devost
- Department of Pharmacology and Therapeutics, McGill University, Montréal, QC H3G 1Y6, Canada
| | - Terence E Hébert
- Department of Pharmacology and Therapeutics, McGill University, Montréal, QC H3G 1Y6, Canada
| | - Graciela Piñeyro
- Centre de Recherche de l'Hôpital Sainte-Justine, Montréal, QC H3T 1C5, Canada
| | - Richard Leduc
- Institut de Pharmacologie de Sherbrooke and Department of Pharmacology-Physiology, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, QC J1H 5N4, Canada
| | - Claudio M Costa-Neto
- Departamento de Bioquímica e Imunologia, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, São Paulo 14049-900, Brazil
| | - Michel Bouvier
- Department of Biochemistry and Molecular Medicine, Institute for Research in Immunology and Cancer (IRIC), Université de Montréal, Montréal, QC H3T 1J4, Canada.
| | - Stéphane A Laporte
- Department of Medicine, Research Institute of the McGill University Health Center (RI-MUHC), McGill University, Montréal, QC H4A 3J1, Canada. .,Department of Pharmacology and Therapeutics, McGill University, Montréal, QC H3G 1Y6, Canada.,Department of Anatomy and Cell Biology, McGill University, Montréal, QC H3A 0C7, Canada
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11
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O'Brien SL, Johnstone EKM, Devost D, Conroy J, Reichelt ME, Purdue BW, Ayoub MA, Kawai T, Inoue A, Eguchi S, Hébert TE, Pfleger KDG, Thomas WG. BRET-based assay to monitor EGFR transactivation by the AT 1R reveals G q/11 protein-independent activation and AT 1R-EGFR complexes. Biochem Pharmacol 2018; 158:232-242. [PMID: 30347205 DOI: 10.1016/j.bcp.2018.10.017] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Accepted: 10/17/2018] [Indexed: 01/09/2023]
Abstract
The type 1 angiotensin II (AngII) receptor (AT1R) transactivates the epidermal growth factor receptor (EGFR), which leads to pathological remodeling of heart, blood vessels and kidney. End-point assays are used as surrogates of EGFR activation, however these downstream readouts are not applicable to live cells, in real-time. Herein, we report the use of a bioluminescence resonance energy transfer (BRET)-based assay to assess recruitment of the EGFR adaptor protein, growth factor receptor-bound protein 2 (Grb2), to the EGFR. In a variety of cell lines, both epidermal growth factor (EGF) and AngII stimulated Grb2 recruitment to EGFR. The BRET assay was used to screen a panel of 9 G protein-coupled receptors (GPCRs) and further developed for other EGFR family members (HER2 and HER3); the AT1R was able to transactivate HER2, but not HER3. Mechanistically, AT1R-mediated ERK1/2 activation was dependent on Gq/11 and EGFR tyrosine kinase activity, whereas the recruitment of Grb2 to the EGFR was independent of Gq/11 and only partially dependent on EGFR tyrosine kinase activity. This Gq/11 independence of EGFR transactivation was confirmed using AT1R mutants and in CRISPR cell lines lacking Gq/11. EGFR transactivation was also apparently independent of β-arrestins. Finally, we used additional BRET-based assays and confocal microscopy to provide evidence that both AngII- and EGF-stimulation promoted AT1R-EGFR heteromerization. In summary, we report an alternative approach to monitoring AT1R-EGFR transactivation in live cells, which provides a more direct and proximal view of this process, including the potential for complexes between the AT1R and EGFR.
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Affiliation(s)
- Shannon L O'Brien
- Receptor Biology Group, The School of Biomedical Sciences, Faculty of Medicine, The University of Queensland, St Lucia 4072, Queensland, Australia
| | - Elizabeth K M Johnstone
- Molecular Endocrinology and Pharmacology, Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands and Centre for Medical Research, The University of Western Australia, Crawley, Western Australia 6009, Australia
| | - Dominic Devost
- Department of Pharmacology and Therapeutics, McGill University, Montreal, QC, Canada
| | - Jacinta Conroy
- Receptor Biology Group, The School of Biomedical Sciences, Faculty of Medicine, The University of Queensland, St Lucia 4072, Queensland, Australia
| | - Melissa E Reichelt
- Receptor Biology Group, The School of Biomedical Sciences, Faculty of Medicine, The University of Queensland, St Lucia 4072, Queensland, Australia
| | - Brooke W Purdue
- Receptor Biology Group, The School of Biomedical Sciences, Faculty of Medicine, The University of Queensland, St Lucia 4072, Queensland, Australia
| | - Mohammed A Ayoub
- Molecular Endocrinology and Pharmacology, Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands and Centre for Medical Research, The University of Western Australia, Crawley, Western Australia 6009, Australia
| | - Tatsuo Kawai
- Cardiovascular Research Centre, Department of Physiology, Lewis Katz School of Medicine at Temple University, Philadelphia, PA, United States
| | - Asuka Inoue
- Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Miyagi 980-8578, Japan
| | - Satoru Eguchi
- Cardiovascular Research Centre, Department of Physiology, Lewis Katz School of Medicine at Temple University, Philadelphia, PA, United States
| | - Terence E Hébert
- Department of Pharmacology and Therapeutics, McGill University, Montreal, QC, Canada
| | - Kevin D G Pfleger
- Molecular Endocrinology and Pharmacology, Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands and Centre for Medical Research, The University of Western Australia, Crawley, Western Australia 6009, Australia; Dimerix Limited, Nedlands, Western Australia 6009, Australia
| | - Walter G Thomas
- Receptor Biology Group, The School of Biomedical Sciences, Faculty of Medicine, The University of Queensland, St Lucia 4072, Queensland, Australia; Centre for Cardiac and Vasculature Biology, The University of Queensland, St Lucia 4072, Queensland, Australia.
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12
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Poujol de Molliens M, Létourneau M, Devost D, Hébert TE, Fournier A, Chatenet D. New insights about the peculiar role of the 28–38 C-terminal segment and some selected residues in PACAP for signaling and neuroprotection. Biochem Pharmacol 2018; 154:193-202. [DOI: 10.1016/j.bcp.2018.04.024] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2018] [Accepted: 04/24/2018] [Indexed: 12/20/2022]
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13
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Sleno R, Devost D, Pétrin D, Zhang A, Bourque K, Shinjo Y, Aoki J, Inoue A, Hébert TE. Conformational biosensors reveal allosteric interactions between heterodimeric AT1 angiotensin and prostaglandin F2α receptors. J Biol Chem 2017; 292:12139-12152. [PMID: 28584054 DOI: 10.1074/jbc.m117.793877] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Revised: 05/31/2017] [Indexed: 11/06/2022] Open
Abstract
G protein-coupled receptors (GPCRs) are conformationally dynamic proteins transmitting ligand-encoded signals in multiple ways. This transmission is highly complex and achieved through induction of distinct GPCR conformations, which preferentially drive specific receptor-mediated signaling events. This conformational capacity can be further enlarged via allosteric effects between dimers, warranting further study of these effects. Using GPCR conformation-sensitive biosensors, we investigated allosterically induced conformational changes in the recently reported F prostanoid (FP)/angiotensin II type 1 receptor (AT1R) heterodimer. Ligand occupancy of the AT1R induced distinct conformational changes in FP compared with those driven by PGF2α in bioluminescence resonance energy transfer (BRET)-based FP biosensors engineered with Renilla luciferase (RLuc) as an energy donor in the C-tail and fluorescein arsenical hairpin binder (FlAsH)-labeled acceptors at different positions in the intracellular loops. We also found that this allosteric communication is mediated through Gαq and may also involve proximal (phospholipase C) but not distal (protein kinase C) signaling partners. Interestingly, β-arrestin-biased AT1R agonists could also transmit a Gαq-dependent signal to FP without activation of downstream Gαq signaling. This transmission of information was specific to the AT1R/FP complex, as activation of Gαq by the oxytocin receptor did not recapitulate the same phenomenon. Finally, information flow was asymmetric in the sense that FP activation had negligible effects on AT1R-based conformational biosensors. The identification of partner-induced GPCR conformations may help identify novel allosteric effects when investigating multiprotein receptor signaling complexes.
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Affiliation(s)
- Rory Sleno
- Department of Pharmacology and Therapeutics, McGill University, Montréal, Québec H3G 1Y6, Canada
| | - Dominic Devost
- Department of Pharmacology and Therapeutics, McGill University, Montréal, Québec H3G 1Y6, Canada
| | - Darlaine Pétrin
- Department of Pharmacology and Therapeutics, McGill University, Montréal, Québec H3G 1Y6, Canada
| | - Alice Zhang
- Department of Pharmacology and Therapeutics, McGill University, Montréal, Québec H3G 1Y6, Canada
| | - Kyla Bourque
- Department of Pharmacology and Therapeutics, McGill University, Montréal, Québec H3G 1Y6, Canada
| | - Yuji Shinjo
- Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Miyagi 980-8578, Japan
| | - Junken Aoki
- Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Miyagi 980-8578, Japan; Japan Agency for Medical Research and Development, Core Research for Evolutional Science and Technology (AMED-CREST), Chiyoda-ku, Tokyo 100-0004, Japan
| | - Asuka Inoue
- Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Miyagi 980-8578, Japan; Japan Science and Technology Agency (JST), Precursory Research for Embryonic Science and Technology (PRESTO), Kawaguchi, Saitama 332-0012, Japan
| | - Terence E Hébert
- Department of Pharmacology and Therapeutics, McGill University, Montréal, Québec H3G 1Y6, Canada.
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14
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Devost D, Sleno R, Pétrin D, Zhang A, Shinjo Y, Okde R, Aoki J, Inoue A, Hébert TE. Conformational Profiling of the AT1 Angiotensin II Receptor Reflects Biased Agonism, G Protein Coupling, and Cellular Context. J Biol Chem 2017; 292:5443-5456. [PMID: 28213525 DOI: 10.1074/jbc.m116.763854] [Citation(s) in RCA: 61] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2016] [Revised: 02/03/2017] [Indexed: 12/16/2022] Open
Abstract
Here, we report the design and use of G protein-coupled receptor-based biosensors to monitor ligand-mediated conformational changes in receptors in intact cells. These biosensors use bioluminescence resonance energy transfer with Renilla luciferase (RlucII) as an energy donor, placed at the distal end of the receptor C-tail, and the small fluorescent molecule FlAsH as an energy acceptor, its binding site inserted at different positions throughout the intracellular loops and C-terminal tail of the angiotensin II type I receptor. We verified that the modifications did not compromise receptor localization or function before proceeding further. Our biosensors were able to capture effects of both canonical and biased ligands, even to the extent of discriminating between different biased ligands. Using a combination of G protein inhibitors and HEK 293 cell lines that were CRISPR/Cas9-engineered to delete Gαq, Gα11, Gα12, and Gα13 or β-arrestins, we showed that Gαq and Gα11 are required for functional responses in conformational sensors in ICL3 but not ICL2. Loss of β-arrestin did not alter biased ligand effects on ICL2P2. We also demonstrate that such biosensors are portable between different cell types and yield context-dependent readouts of G protein-coupled receptor conformation. Our study provides mechanistic insights into signaling events that depend on either G proteins or β-arrestin.
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Affiliation(s)
- Dominic Devost
- From the Department of Pharmacology and Therapeutics, McGill University, Montréal, Québec H3G 1Y6, Canada
| | - Rory Sleno
- From the Department of Pharmacology and Therapeutics, McGill University, Montréal, Québec H3G 1Y6, Canada
| | - Darlaine Pétrin
- From the Department of Pharmacology and Therapeutics, McGill University, Montréal, Québec H3G 1Y6, Canada
| | - Alice Zhang
- From the Department of Pharmacology and Therapeutics, McGill University, Montréal, Québec H3G 1Y6, Canada
| | - Yuji Shinjo
- the Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Miyagi 980-8578, Japan
| | - Rakan Okde
- From the Department of Pharmacology and Therapeutics, McGill University, Montréal, Québec H3G 1Y6, Canada
| | - Junken Aoki
- the Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Miyagi 980-8578, Japan.,the Japan Agency for Medical Research and Development-Core Research for Evolutional Science and Technology (AMED-CREST), Chiyoda-ku, Tokyo 100-0004, Japan, and
| | - Asuka Inoue
- the Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Miyagi 980-8578, Japan.,the Precursory Research for Embryonic Science and Technology (PRESTO), Japan Science and Technology Agency (JST), Kawaguchi, Saitama 332-0012, Japan
| | - Terence E Hébert
- From the Department of Pharmacology and Therapeutics, McGill University, Montréal, Québec H3G 1Y6, Canada,
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15
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Bourque K, Pétrin D, Sleno R, Devost D, Zhang A, Hébert TE. Distinct Conformational Dynamics of Three G Protein-Coupled Receptors Measured Using FlAsH-BRET Biosensors. Front Endocrinol (Lausanne) 2017; 8:61. [PMID: 28439254 PMCID: PMC5383666 DOI: 10.3389/fendo.2017.00061] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/20/2017] [Accepted: 03/21/2017] [Indexed: 12/30/2022] Open
Abstract
A number of studies have profiled G protein-coupled receptor (GPCR) conformation using fluorescent biaresenical hairpin binders (FlAsH) as acceptors for BRET or FRET. These conformation-sensitive biosensors allow reporting of movements occurring on the intracellular surface of a receptor to investigate mechanisms of receptor activation and function. Here, we generated eight FlAsH-BRET-based biosensors within the sequence of the β2-adrenergic receptor (β2AR) and compared agonist-induced responses to the angiotensin II receptor type I (AT1R) and the prostaglandin F2α receptor (FP). Although all three receptors had FlAsH-binding sequences engineered into the third intracellular loops and carboxyl-terminal domain, both the magnitude and kinetics of the BRET responses to ligand were receptor-specific. Biosensors in ICL3 of both the AT1R and FP responded robustly when stimulated with their respective full agonists as opposed to the β2AR where responses in the third intracellular loop were weak and transient when engaged by isoproterenol. C-tail sensors responses were more robust in the β2AR and AT1R but not in FP. Even though GPCRs share the heptahelical topology and are expressed in the same cellular background, different receptors have unique conformational fingerprints.
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Affiliation(s)
- Kyla Bourque
- Department of Pharmacology and Therapeutics, McGill University, Montreal, QC, Canada
| | - Darlaine Pétrin
- Department of Pharmacology and Therapeutics, McGill University, Montreal, QC, Canada
| | - Rory Sleno
- Department of Pharmacology and Therapeutics, McGill University, Montreal, QC, Canada
| | - Dominic Devost
- Department of Pharmacology and Therapeutics, McGill University, Montreal, QC, Canada
| | - Alice Zhang
- Department of Pharmacology and Therapeutics, McGill University, Montreal, QC, Canada
| | - Terence E. Hébert
- Department of Pharmacology and Therapeutics, McGill University, Montreal, QC, Canada
- *Correspondence: Terence E. Hébert,
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16
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Namkung Y, Radresa O, Armando S, Devost D, Beautrait A, Le Gouill C, Laporte SA. Quantifying biased signaling in GPCRs using BRET-based biosensors. Methods 2016; 92:5-10. [DOI: 10.1016/j.ymeth.2015.04.010] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2015] [Accepted: 04/11/2015] [Indexed: 01/14/2023] Open
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17
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Devost D, Audet N, Zhou C, Kobayashi H, Bonin H, Lukashova V, Le Gouill C, Bouvier M, Hébert TE. Cellular and subcellular context determine outputs from signaling biosensors. Methods Cell Biol 2016; 132:319-37. [DOI: 10.1016/bs.mcb.2015.11.010] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
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18
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Sleno R, Pétrin D, Devost D, Goupil E, Zhang A, Hébert TE. Designing BRET-based conformational biosensors for G protein-coupled receptors. Methods 2015; 92:11-8. [PMID: 25962643 DOI: 10.1016/j.ymeth.2015.05.003] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2015] [Revised: 04/30/2015] [Accepted: 05/02/2015] [Indexed: 12/16/2022] Open
Abstract
Ligand-biased signaling is starting to have significant impact on drug discovery programs in the pharmaceutical industry and has reinvigorated our understanding of pharmacological efficacy. As such, many investigators and screening campaigns are now being directed at a larger section of the signaling responses downstream of an individual G protein-coupled receptor. Many biosensor-based platforms have been developed to capture signaling signatures. Despite our growing ability to use such signaling signatures, we remain hampered by the fact that signaling signatures may be particular to an individual cell type and thus our platforms may not be portable from cell to cell, necessitating further cell-specific biosensor development. Here, we provide a complementary strategy based on capturing receptor-proximal conformational profiles using intra-molecular BRET-based sensors composed of a Renilla luciferase donor engineered into the carboxy-terminus and CCPGCC motifs which bind fluorescent hairpin arsenical dyes engineered into different positions in intracellular loop 3 of FP, the receptor for PGF2α. We discuss the design and optimization of such sensors for orthosteric and allosteric ligands.
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Affiliation(s)
- Rory Sleno
- Department of Pharmacology and Therapeutics, McGill University, Canada
| | - Darlaine Pétrin
- Department of Pharmacology and Therapeutics, McGill University, Canada
| | - Dominic Devost
- Department of Pharmacology and Therapeutics, McGill University, Canada
| | - Eugénie Goupil
- Department of Pharmacology and Therapeutics, McGill University, Canada
| | - Alice Zhang
- Department of Pharmacology and Therapeutics, McGill University, Canada
| | - Terence E Hébert
- Department of Pharmacology and Therapeutics, McGill University, Canada.
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19
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Goupil E, Fillion D, Clément S, Luo X, Devost D, Sleno R, Pétrin D, Saragovi HU, Thorin É, Laporte SA, Hébert TE. Angiotensin II type I and prostaglandin F2α receptors cooperatively modulate signaling in vascular smooth muscle cells. J Biol Chem 2014; 290:3137-48. [PMID: 25512374 DOI: 10.1074/jbc.m114.631119] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
The angiotensin II type I (AT1R) and the prostaglandin F2α (PGF2α) F prostanoid (FP) receptors are both potent regulators of blood pressure. Physiological interplay between AT1R and FP has been described. Abdominal aortic ring contraction experiments revealed that PGF2α-dependent activation of FP potentiated angiotensin II-induced contraction, whereas FP antagonists had the opposite effect. Similarly, PGF2α-mediated vasoconstriction was symmetrically regulated by co-treatment with AT1R agonist and antagonist. The underlying canonical Gαq signaling via production of inositol phosphates mediated by each receptor was also regulated by antagonists for the other receptor. However, binding to their respective agonists, regulation of receptor-mediated MAPK activation and vascular smooth muscle cell growth were differentially or asymmetrically regulated depending on how each of the two receptors were occupied by either agonist or antagonist. Physical interactions between these receptors have never been reported, and here we show that AT1R and FP form heterodimeric complexes in both HEK 293 and vascular smooth muscle cells. These findings imply that formation of the AT1R/FP dimer creates a novel allosteric signaling unit that shows symmetrical and asymmetrical signaling behavior, depending on the outcome measured. AT1R/FP dimers may thus be important in the regulation of blood pressure.
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Affiliation(s)
- Eugénie Goupil
- From the Department of Pharmacology and Therapeutics, McGill University, Montréal, Québec H3G 1Y6
| | - Dany Fillion
- From the Department of Pharmacology and Therapeutics, McGill University, Montréal, Québec H3G 1Y6
| | - Stéphanie Clément
- From the Department of Pharmacology and Therapeutics, McGill University, Montréal, Québec H3G 1Y6
| | - Xiaoyan Luo
- the Centre de Recherche, Institut de Cardiologie de Montréal, Montréal, Québec H1T 1C8, Canada
| | - Dominic Devost
- From the Department of Pharmacology and Therapeutics, McGill University, Montréal, Québec H3G 1Y6
| | - Rory Sleno
- From the Department of Pharmacology and Therapeutics, McGill University, Montréal, Québec H3G 1Y6
| | - Darlaine Pétrin
- From the Department of Pharmacology and Therapeutics, McGill University, Montréal, Québec H3G 1Y6
| | - H Uri Saragovi
- From the Department of Pharmacology and Therapeutics, McGill University, Montréal, Québec H3G 1Y6, the Lady Davis Institute, Montréal Jewish General Hospital, Montréal, Québec H3T 1E2, and
| | - Éric Thorin
- the Centre de Recherche, Institut de Cardiologie de Montréal, Montréal, Québec H1T 1C8, Canada
| | - Stéphane A Laporte
- From the Department of Pharmacology and Therapeutics, McGill University, Montréal, Québec H3G 1Y6, the Department of Medicine, McGill University Health Center Research Institute, Montréal, Québec H3A 2B2, the Department of Anatomy and Cell Biology, McGill University, Montréal, Québec H3A 0CT,
| | - Terence E Hébert
- From the Department of Pharmacology and Therapeutics, McGill University, Montréal, Québec H3G 1Y6,
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20
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Poursharifi P, Lapointe M, Pétrin D, Devost D, Gauvreau D, Hébert TE, Cianflone K. C5L2 and C5aR interaction in adipocytes and macrophages: insights into adipoimmunology. Cell Signal 2012; 25:910-8. [PMID: 23268185 DOI: 10.1016/j.cellsig.2012.12.010] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2012] [Revised: 11/29/2012] [Accepted: 12/12/2012] [Indexed: 11/18/2022]
Abstract
Obesity is associated with inflammation characterized by increased infiltration of macrophages into adipose tissue. C5aR-like receptor 2 (C5L2) has been identified as a receptor for acylation-stimulating protein (ASP) and the inflammatory factor C5a, which also binds C5aR. The present study examines the effects of ligands ASP and C5a on interactions between the receptors C5L2 and C5aR in 3T3-L1 adipocytes and J774 macrophages. BRET experiments indicate that C5L2 and C5aR form homo- and heterodimers in transfected HEK 293 cells, which were stable in the presence of ligand. Cell surface receptor levels of C5L2 and C5aR increased during 3T3-L1 adipocyte differentiation; both receptors are also highly expressed in J774 macrophages. Using confocal microscopy to evaluate endogenous receptors in adipocytes following stimulation with ASP or C5a, C5L2 is internalized with increasing perinuclear colocalization with C5aR. There is little C5a-dependent colocalization in macrophages. While adipocyte-conditioned medium (ACM) increased C5L2-C5aR colocalization in macrophages, this was blocked by C5a. ASP stimulation increased Akt (Ser(473)) phosphorylation in both cell types; C5a induced slight Akt phosphorylation in adipocytes with less effect in macrophages. ASP, but not C5a, increased fatty acid uptake/esterification in adipocytes. C5L2-C5aR homodimerization versus heterodimerization may thus contribute to differential responses obtained following ASP vs C5a stimulation of adipocytes and macrophages, providing new insights into the complex interaction between these two cell types within adipose tissue. Studying the mechanisms involved in the differential responses of C5L2-C5aR activation based on cell type will further our understanding of inflammatory processes in obesity.
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Affiliation(s)
- Pegah Poursharifi
- Centre de Recherche de Institut Universitaire de Cardiologie et de Pneumologie de Québec (CRIUCPQ), Québec, QC, Canada
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21
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Murat B, Devost D, Andrés M, Mion J, Boulay V, Corbani M, Zingg HH, Guillon G. V1b and CRHR1 receptor heterodimerization mediates synergistic biological actions of vasopressin and CRH. Mol Endocrinol 2012; 26:502-20. [PMID: 22301784 DOI: 10.1210/me.2011-1202] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Vasopressin (AVP) and CRH synergistically regulate adrenocorticotropin and insulin release at the level of the pituitary and pancreas, respectively. Here, we first extended these AVP and CRH coregulation processes to the adrenal medulla. We demonstrate that costimulation of chromaffin cells by AVP and CRH simultaneously induces a catecholamine secretion exceeding the one induced by each hormone alone, thus demonstrating a net potentiation. To further elucidate the molecular mechanisms underlying this synergism, we coexpressed human V1b and CRH receptor (CRHR)1 receptor in HEK293 cells. In this heterologous system, AVP also potentiated CRH-stimulated cAMP accumulation in a dose-dependent and saturable manner. This effect was only partially mimicked by phorbol ester or inhibited by a phospholipase C inhibitor respectively. This finding suggests the existence of an new molecular mechanism, independent from second messenger cross talk. Similarly, CRH potentiated the AVP-induced inositol phosphates production. Using bioluminescence resonance energy transfer, coimmunoprecipitation, and receptor rescue experiments, we demonstrate that V1b and CRHR1 receptors assemble as heterodimers. Moreover, new pharmacological properties emerged upon receptors cotransfection. Taken together, these data strongly suggest that direct molecular interactions between V1b and CRHR1 receptors play an important role in mediating the synergistic interactions between these two receptors.
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Affiliation(s)
- Brigitte Murat
- Institut de Génomique Fonctionnelle, 141 Rue de la Cardonille, Montpellier Cedex 05, France
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22
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Wrzal PK, Devost D, Pétrin D, Goupil E, Iorio-Morin C, Laporte SA, Zingg HH, Hébert TE. Allosteric interactions between the oxytocin receptor and the β2-adrenergic receptor in the modulation of ERK1/2 activation are mediated by heterodimerization. Cell Signal 2011; 24:342-50. [PMID: 21963428 DOI: 10.1016/j.cellsig.2011.09.020] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2011] [Revised: 09/09/2011] [Accepted: 09/11/2011] [Indexed: 12/22/2022]
Abstract
The oxytocin receptor (OTR) and the β(2)-adrenergic receptor (β(2)AR) are key regulators of uterine contraction. These two receptors are targets of tocolytic agents used to inhibit pre-term labor. Our recent study on the nature of OTR- and β(2)AR-mediated ERK1/2 activation in human hTERT-C3 myometrial cells suggested the presence of an OTR/β(2)AR hetero-oligomeric complex (see companion article). The goal of this study was to investigate potential allosteric interactions between OTR and β(2)AR and establish the nature of the interactions between these receptors in myometrial cells. We found that OTR-mediated ERK1/2 activation was attenuated significantly when cells were pretreated with the β(2)AR agonist isoproterenol or two antagonists, propranolol or timolol. In contrast, pretreatment of cells with a third β(2)AR antagonist, atenolol resulted in an increase in OTR-mediated ERK1/2 activation. Similarly, β(2)AR-mediated ERK1/2 activation was strongly attenuated by pretreatment with the OTR antagonists, atosiban and OTA. Physical interactions between OTR and β(2)AR were demonstrated using co-immunoprecipitation, bioluminescence resonance energy transfer (BRET) and protein-fragment complementation (PCA) assays in HEK 293 cells, the latter experiments indicating the interactions between the two receptors were direct. Our analyses suggest physical interactions between OTR and β(2)AR in the context of a new heterodimer pair lie at the heart of the allosteric effects.
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Affiliation(s)
- Paulina K Wrzal
- Department of Pharmacology and Therapeutics, McGill University, Montréal, Québec, Canada
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23
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Goupil E, Tassy D, Bourguet C, Quiniou C, Wisehart V, Pétrin D, Le Gouill C, Devost D, Zingg HH, Bouvier M, Saragovi HU, Chemtob S, Lubell WD, Claing A, Hébert TE, Laporte SA. A novel biased allosteric compound inhibitor of parturition selectively impedes the prostaglandin F2alpha-mediated Rho/ROCK signaling pathway. J Biol Chem 2010; 285:25624-36. [PMID: 20551320 DOI: 10.1074/jbc.m110.115196] [Citation(s) in RCA: 78] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The prostaglandin F2alpha (PGF2alpha) receptor (FP) is a key regulator of parturition and a target for pharmacological management of preterm labor. However, an incomplete understanding of signaling pathways regulating myometrial contraction hinders the development of improved therapeutics. Here we used a peptidomimetic inhibitor of parturition in mice, PDC113.824, whose structure was based on the NH(2)-terminal region of the second extracellular loop of FP receptor, to gain mechanistic insight underlying FP receptor-mediated cell responses in the context of parturition. We show that PDC113.824 not only delayed normal parturition in mice but also that it inhibited both PGF2alpha- and lipopolysaccharide-induced preterm labor. PDC113.824 inhibited PGF2alpha-mediated, G(alpha)(12)-dependent activation of the Rho/ROCK signaling pathways, actin remodeling, and contraction of human myometrial cells likely by acting as a non-competitive, allosteric modulator of PGF2alpha binding. In contrast to its negative allosteric modulating effects on Rho/ROCK signaling, PDC113.824 acted as a positive allosteric modulator on PGF2alpha-mediated protein kinase C and ERK1/2 signaling. This bias in receptor-dependent signaling was explained by an increase in FP receptor coupling to G(alpha)(q), at the expense of coupling to G(alpha)(12). Our findings regarding the allosteric and biased nature of PDC113.824 offer new mechanistic insights into FP receptor signaling relevant to parturition and suggest novel therapeutic opportunities for the development of new tocolytic drugs.
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Affiliation(s)
- Eugénie Goupil
- Department of Medicine, McGill University Health Center Research Institute, Montréal H3A 1A1, Canada
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24
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Abstract
The nonapeptide oxytocin (OT) mediates a wide spectrum of biological action, many of them related to reproduction. Recently, we have shown that OT exerts a trophic effect on uterine smooth muscle cells and induces dephosphorylation, and thus activation, of the translation elongation factor eukaryotic elongation factor 2 (eEF2). The present study was designed to elucidate the mechanisms underlying this novel action of OT in the well-characterized human myometrial cell line hTERT-C3. Pathways known to induce eEF2 dephosphorylation are mammalian target of rapamycin (mTOR), and the MAPKs ERK1/2 and p38. Using a panel of chemical inhibitors of specific signaling pathways, we determined that none of these pathways played a role in OT-mediated eEF2 dephosphorylation. Because the OT receptor is a G protein-coupled receptor linked to Galphaq, we tested the possibility that this OT action was mediated via protein kinase C (PKC). PKC activity was blocked by application of the general PKC chemical inhibitor Go6983 or by incubation with the cell-permeable PKC inhibitor peptide myr-psi PKC. With either approach, the effect of OT on eEF2 dephosphorylation was suppressed, indicating that the PKC pathway is essential for this OT action. Consistent with this idea, we also found that direct stimulation of PKC with the phorbol ester phorbol 12-myristate 13-acetate induced eEF2 dephosphorylation. Moreover, we observed that the stimulatory effect of OT on [(35)S]methionine incorporation into nascent proteins was blocked by PKC inhibition. Overall, these results define a novel hormonal signaling pathway that leads to eEF2 dephosphorylation and activation of protein synthesis.
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Affiliation(s)
- Dominic Devost
- Department of Pharmacology & Therapeutics, McGill University, 3655 Promenade Sir-William-Osler, Montreal, Quebec, Canada H3G 1Y6
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25
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Chevillard G, Derjuga A, Devost D, Zingg HH, Blank V. Identification of interleukin-1β regulated genes in uterine smooth muscle cells. Reproduction 2007; 134:811-22. [DOI: 10.1530/rep-07-0289] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
We analyzed the response of uterine smooth muscle cells to interleukin-1β (IL-1β). We first showed that PHM1-31 myometrial cells, our cellular model, are contractile. To determine the molecular mechanisms of uterine smooth muscle cell activation by proinflammatory cytokines, we performed genechip expression array profiling studies of PHM1-31 cells in the absence and the presence of IL-1β. In total, we identified 198 known genes whose mRNA levels are significantly modulated (> 2.0-fold change) following IL-1β exposure. We confirmed the expression changes for selected genes by independent mRNA and protein analysis. The group of genes induced by IL-1β includes transcription factors and inflammatory response genes such as nuclear factor of κ light polypeptide gene enhancer in B-cells (NFκB), pentraxin-related gene (PTX3), and tumor necrosis factor α-induced protein 3/A20 (TNFAIP3/A20). We also found up-regulation of chemokines like C-X-C motif ligand 3 (CXCL3) and extracellular matrix remodeling signaling molecules like tenascin C (TNC). Our data suggest that IL-1β elicits the rapid activation of a cellular network of genes particularly implicated in inflammatory response that may create a cellular environment favorable for myometrial cell contraction. Our results provide novel insights into the mechanisms of uterine smooth muscle cell regulation and possibly infection-induced preterm labor.
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26
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Gassanov N, Devost D, Danalache B, Noiseux N, Jankowski M, Zingg HH, Gutkowska J. Functional activity of the carboxyl-terminally extended oxytocin precursor Peptide during cardiac differentiation of embryonic stem cells. Stem Cells 2007; 26:45-54. [PMID: 17951221 DOI: 10.1634/stemcells.2007-0289] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The hypothalamic post-translational processing of oxytocin (OT)-neurophysin precursor involves the formation of C-terminally extended OT forms (OT-X) that serve as intermediate prohormones. Despite abundant expression of the entire functional OT system in the developing heart, the biosynthesis and implication of OT prohormones in cardiomyogenesis remain unknown. In the present work, we investigated the involvement of OT-X in cardiac differentiation of embryonic stem (ES) cells. Functional studies revealed the OT receptor-mediated cardiomyogenic action of OT-Gly-Lys-Arg (OT-GKR). To obtain further insight into the mechanisms of OT-GKR-induced cardiac effects, we generated ES cell lines overexpressing the OT-GKR gene and enhanced green fluorescent protein (EGFP). The functionality of the OT-GKR/EGFP construct was assessed by fluorescence microscopy and flow cytometry, with further confirmation by radioimmunoassay and immunostaining. Increased spontaneously beating activity of OT-GKR/EGFP-expressing embryoid bodies and elevated expression of GATA-4 and myosin light chain 2v cardiac genes indicated an inductive effect of endogenous OT-GKR on ES cell-derived cardiomyogenesis. Furthermore, patch-clamp experiments demonstrated induction of ventricular phenotypes in OT-GKR/EGFP-transfected and in OT-GKR-treated cardiomyocytes. Increased connexin 43 protein in OT-GKR/EGFP-expressing cells further substantiated the evidence that OT-GKR modifies cardiac differentiation toward the ventricular sublineage. In conclusion, this report provides new evidence of the biological activity of OT-X, notably OT-GKR, during cardiomyogenic differentiation.
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Affiliation(s)
- Natig Gassanov
- Department of Internal Medicine III, University of Cologne, Cologne, Germany
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27
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Abstract
One of the classical biological actions mediated by the posterior pituitary hormone oxytocin (OT) is contraction of the uterus at parturition. Moreover, premature activation of the OT system is thought to contribute to preterm labor, a major clinical problem in obstetrical practice. However, the molecular mechanisms linking activation of the OT receptor (OTR) to myometrial contractions are not fully understood. Here, we describe an in vitro system that should serve as a useful tool to study this question at a cellular level. The system consists of a collagen lattice contraction assay and two different human myometrial cell lines: a cell clone from a telomerase-immortalized human myometrial cell population (hTERT-C3) as well as a cell line derived from a primary culture of human myometrial cells (M11). Using this approach, we observed that 1 nM OT promoted an almost maximal effect on cell contraction in both cell lines tested. Furthermore, this dose-dependent, OT-induced contraction was antagonized by the specific OTR antagonist d(CH(2))(5)[Tyr(Me)(2),Thr(4),Tyr-NH(2)(9)]OVT as well as the clinically used antagonist atosiban. This cell line-based contraction assay enables the application of molecular tools aimed at suppressing or overexpressing specific genes. It is also amenable to high-throughput testing approaches. Therefore, this system represents a powerful and improved experimental model that should facilitate the study of the molecular signal transduction pathways involved in the uterotonic actions of OT.
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Affiliation(s)
- Dominic Devost
- Dept. of Pharmacology and Therapeutics, McGill University, 3655 Promenade Sir-William-Osler, Montreal, QC, H3G 1Y6, Canada
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28
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Abstract
The oxytocin (OT) receptor (OTR) mediates a wide spectrum of biological actions and is expressed in a large number of different tissues, including uterine, breast, and lung tumors. To define more completely the intracellular signaling mechanisms linked to OTR activation, we have used a phosphoproteomics approach and have characterized changes in the phosphorylation states of intracellular proteins in response to OTR activation in OTR-expressing cell lines. Using a specific antiphosphothreonine antibody, we observed several distinct changes in the threonine phosphorylation patterns. The most prominent change involved dephosphorylation of a 95-kDa moiety. Purification by ion exchange chromatography combined with one- and two-dimensional polyacrylamide gel electrophoresis followed by N-terminal micro-sequence analysis revealed that the 95-kDa moiety corresponded to eukaryotic elongation factor 2. This protein is a key regulator of cellular protein synthesis and mediates, upon dephosphorylation, the translocation step of peptide chain elongation. Dose-response curves in myometrial cells expressing the endogenous OTR indicated a significant effect of OT on eukaryotic elongation factor 2 dephosphorylation at 1 nM, a concentration close to the dissociation constant (K(d)) of OT. Time course analysis indicates that the effect is rapid with a significant effect occurring at 5 min. To determine directly the effect of OT on protein synthesis, the incorporation of [35S]Met into total protein was assessed. In myometrial cells, OTR activation led to significant 29% increase in total protein synthesis over a 2-h period. These findings establish a novel link between OTR activation and cellular protein synthesis and thus define a mechanism by which OT assumes a so far unrecognized, physiologically relevant trophic function.
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Affiliation(s)
- Dominic Devost
- Department of Medicine, McGill University, Montreal, Quebec, Canada H3A 1A1
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29
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Raccurt M, Smallwood S, Mertani HC, Devost D, Abbaci K, Boutin JM, Morel G. Cloning, expression and regulation of chicken ovalbumin upstream promoter transcription factors (COUP-TFII and EAR-2) in the rat anterior pituitary gland. Neuroendocrinology 2005; 82:233-44. [PMID: 16721029 DOI: 10.1159/000092752] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/13/2005] [Accepted: 02/14/2006] [Indexed: 11/19/2022]
Abstract
Chicken ovalbumin upstream promoter transcription factors (COUP-TF)-II (NR2F2) and EAR-2 (NR2F6) are structurally related orphan members of the nuclear receptors superfamily. There are growing evidences that these factors play important roles during processes of differentiation and proliferation of several tissues. To better understand their role in the differentiated adult rat pituitary gland, we cloned COUP-TFII and EAR-2 cDNAs from an anterior pituitary cDNA library. Subsequently, we raised and characterized specific antibodies to the N-terminal domain of both nuclear receptors. We next examined their cellular and subcellular distribution in the pituitary gland and determined their regulation during pregnancy. COUP-TFII and EAR-2 pituitary genes display, respectively, 90 and 100% homologies with their human and mouse homologues. Cellular expression of both nuclear receptors was mainly detected in the lactotropes of male and female rats, with a prominent distribution in the nuclear compartment for EAR-2, and interestingly both proteins were significantly upregulated in pituitaries of pregnant vs. cycling female rats. Thus, our results have characterized cloning of rat pituitary COUP-TFII and EAR-2 genes, demonstrated that they are both specifically expressed in lactotropes, and strongly suggested that they may play an important role in modulating prolactin (PRL) gene expression during pregnancy.
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MESH Headings
- Amino Acid Sequence
- Animals
- Blotting, Western
- COUP Transcription Factor II/analysis
- COUP Transcription Factor II/genetics
- COUP Transcription Factor II/immunology
- COUP Transcription Factor II/physiology
- Cell Differentiation/physiology
- Cell Proliferation
- Cloning, Molecular
- DNA, Complementary/analysis
- DNA, Complementary/genetics
- Electrophoresis, Polyacrylamide Gel
- Female
- Gene Expression Regulation/physiology
- Immunohistochemistry
- Male
- Molecular Sequence Data
- Pituitary Gland, Anterior/chemistry
- Pituitary Gland, Anterior/cytology
- Pituitary Gland, Anterior/metabolism
- Pituitary Gland, Anterior/physiology
- Pregnancy
- Pregnancy, Animal/genetics
- Pregnancy, Animal/physiology
- Prolactin/analysis
- Prolactin/genetics
- Prolactin/physiology
- Rats
- Rats, Wistar
- Receptors, Steroid/analysis
- Receptors, Steroid/genetics
- Receptors, Steroid/immunology
- Receptors, Steroid/physiology
- Transcription Factors/analysis
- Transcription Factors/genetics
- Transcription Factors/immunology
- Transcription Factors/physiology
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Affiliation(s)
- Mireille Raccurt
- UMR 5123 CNRS Université Claude Bernard Lyon I, Physiologie Intégrative Cellulaire et Moléculaire, Villeurbanne, France
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30
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Hasbi A, Devost D, Laporte SA, Zingg HH. Real-Time Detection of Interactions between the Human Oxytocin Receptor and G Protein-Coupled Receptor Kinase-2. Mol Endocrinol 2004; 18:1277-86. [PMID: 14976224 DOI: 10.1210/me.2003-0440] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
AbstractAlthough the oxytocin receptor (OTR) mediates many important functions including uterine contractions, milk ejection, and maternal behavior, the mechanisms controlling agonist-induced OTR desensitization have remained unclear, and attempts to demonstrate involvement of a G protein-coupled receptor kinase (GRK) have so far failed. Using the OTR as a model, we demonstrate here directly for the first time the dynamics of agonist-induced interactions of a GRK with a G protein-coupled receptor in real time, using time-resolved bioluminescence resonance energy transfer. GRK2/receptor interactions started within 4 sec, peaked at 10 sec, and decreased to less than 40% within 8 min. By contrast, β-arrestin/OTR interactions initiated only at 10 sec, reached plateau levels at 120 sec, but remained stable with little decrease thereafter. Physical GRK2/OTR association was further demonstrated by coimmunoprecipitation of endogenous GRK2 with activated OTR. In COS-7 cells, which express low levels of GRK2 and β-arrestin, overexpression of GRK2 and β-arrestin increased receptor phosphorylation, desensitization, and internalization to the high levels observed in human embryonic kidney 293 cells. By contrast, specific inhibition of endogenous GRK2 by dominant-negative mutants robustly inhibited OTR phosphorylation and internalization as well as arrestin/OTR interactions. These data characterize the temporal and causal relationship of GRK-2/OTR and β-arrestin/OTR interactions and establish GRK/OTR interaction as a prerequisite for β-arrestin-mediated OTR desensitization.
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Affiliation(s)
- Ahmed Hasbi
- Laboratory of Molecular Endocrinology, Royal Victoria Hospital, 687 Pine Avenue West, Montreal, Quebec, Canada H3A 1A1
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31
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Hum D, Besnard S, Sanchez R, Devost D, Gossard F, Hamet P, Tremblay J. Characterization of a cGMP-response element in the guanylyl cyclase/natriuretic peptide receptor A gene promoter. Hypertension 2004; 43:1270-8. [PMID: 15096467 DOI: 10.1161/01.hyp.0000126920.93207.53] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Previous studies have shown that atrial natriuretic peptide (ANP) can inhibit transcription of its receptor, guanylyl cyclase A, by a mechanism dependent on cGMP and have suggested the presence of a putative cGMP-response element (cGMP-RE) in the Npr1 gene promoter. To localize and characterize the putative cis-acting element, we have subcloned a 1520-bp fragment of the rat Npr1 promoter in an expression vector containing the luciferase reporter gene. Several fragments, generated by exonuclease III-directed deletions, were transiently transfected into cells to measure their promoter activity. Deletion from -1520 to -1396 of a 1520-bp-long Npr1 promoter led to a 5-fold increase in luciferase activity. Subsequent deletion to the position -1307 resulted in a decrease of luciferase activity by 90%. Preincubation of cells with 100 nM of ANP or 100 microM 8-bromo-cGMP inhibited luciferase activity of the 1520-bp and 1396-bp-long fragments, but not the activity of the 1307-bp fragment, suggesting that the cGMP-RE is localized between positions -1396 and -1307. The cGMP regulatory region was narrowed by gel shift assays and footprinting to position -1372 to -1354 from the transcription start site of Npr1 and indicated its interaction with transcriptional factor(s). Cross-competition experiments with mutated oligonucleotides led to the definition of a consensus sequence (-1372 AaAtRKaNTTCaAcAKTY -1354) for the novel cGMP-RE, which is conserved in the human (75% identity) and mouse (95% identity) Npr1 promoters.
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Affiliation(s)
- David Hum
- Centre de recherche, Centre hospitalier de l'Université de Montréal-Hôtel-Dieu, Montréal, Québec, Canada
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32
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Abstract
Using two different coimmunoprecipitation strategies as well as bioluminescence resonance energy transfer (BRET) techniques, we determined that the human oxytocin receptor forms dimeric and oligomeric complexes in vivo in intact living cells, and that these complexes exist at the cell surface level. Using a BRET-based assay, we found that oligomers can form between oxytocin receptors themselves (homo-oligomers) as well as, with a reduced affinity, between the oxytocin receptor and related members of the vasopressin receptor family (V1a and V2 receptors), but not with the more remotely related bradykinin receptor. The existence of oxytocin receptor oligomers at the level of the cell surface was demonstrated by a coimmunoprecipitation approach involving direct antibody exposure of intact living cells. Furthermore, this approach demonstrated that cell surface oxytocin receptor oligomerization is ligand independent. However, agonist addition led to an apparent rapid decrease in receptor oligomerization, as assessed by the coimmunoprecipitation approach, indicating that agonist exposure may modulate the oligomerization status. It remains to be determined to what extent oxytocin receptor oligomerization impacts on signal transduction.
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Affiliation(s)
- D Devost
- Department of Medicine, McGill University, Montreal, Quebec, Canada
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33
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Lacerte A, Lee EH, Reynaud R, Canaff L, De Guise C, Devost D, Ali S, Hendy GN, Lebrun JJ. Activin inhibits pituitary prolactin expression and cell growth through Smads, Pit-1 and menin. Mol Endocrinol 2004; 18:1558-69. [PMID: 15031321 DOI: 10.1210/me.2003-0470] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Activin, a member of the TGFbeta superfamily, is a negative regulator of cell growth and prolactin (PRL) production in pituitary lactotrope cells. However, the mechanisms by which this growth factor exerts its growth-inhibitory and -repressive effect on PRL remain unclear. In this study, we show that activin negatively regulates PRL expression at the transcriptional level through the Smad pathway and the multiple endocrine neoplasia type 1 gene product, menin. Our results also demonstrate that the tumor suppressor menin is required for activin-induced growth arrest of somatolactotrope cells. Moreover, we show that activin represses transcription and expression of Pit-1, a pituitary transcription factor that is essential for maintenance and development of lactotrope cells. We defined two Pit-1 DNA-binding sites in the proximal region of the PRL promoter as critical for the activin-mediated inhibition. Together, our results highlight the Smad pathway and the tumor suppressor menin as key regulators of activin effects on PRL and Pit-1 expression, as well as on cell growth inhibition, and emphasize the critical role of activin in the regulation of pituitary function.
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MESH Headings
- Activins/metabolism
- Animals
- Blotting, Northern
- Blotting, Western
- CHO Cells
- Cell Line, Tumor
- Cell Proliferation
- Cell Survival
- Coloring Agents/pharmacology
- Cricetinae
- DNA-Binding Proteins/metabolism
- Down-Regulation
- Gene Expression Regulation
- Genes, Reporter
- Humans
- Mutagenesis
- Oligonucleotides, Antisense/pharmacology
- Pituitary Gland/metabolism
- Prolactin/biosynthesis
- Promoter Regions, Genetic
- Protein Structure, Tertiary
- Proto-Oncogene Proteins/metabolism
- RNA, Messenger/metabolism
- RNA, Small Interfering/metabolism
- Rats
- Smad Proteins
- Tetrazolium Salts/pharmacology
- Thiazoles/pharmacology
- Time Factors
- Trans-Activators/metabolism
- Transcription Factor Pit-1
- Transcription Factors/metabolism
- Transcription, Genetic
- Transfection
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Affiliation(s)
- Annie Lacerte
- Department of Medicine, Royal Victoria Hospital, Montreal, Quebec, H3A 1A1, Canada
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34
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Devost D, Zingg HH. Identification of dimeric and oligomeric complexes of the human oxytocin receptor by co-immunoprecipitation and bioluminescence resonance energy transfer. J Mol Endocrinol 2003; 31:461-71. [PMID: 14664707 DOI: 10.1677/jme.0.0310461] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The nonapeptide hormone oxytocin exerts many important biological functions, including uterine contractions during parturition and milk ejection during lactation. The manifold effects of oxytocin are mediated by a single oxytocin receptor (OTR) type, a member of the super-family of G-protein-coupled receptors. There is accumulating recent evidence that certain G-protein-coupled receptors exist in the form of oligomeric complexes. Here we demonstrate, using two different co-immunoprecipitation strategies as well as bioluminescence resonance energy transfer techniques, that the OTR is capable of forming oligomeric complexes in vivo and that these complexes exist at the cell surface membrane. The human OTR was N-terminally tagged with either a Myc or Flag epitope and transiently expressed in COS-7 cells. Cell lysates were immunoprecipitated using an anti-Flag antibody and analyzed by SDS-PAGE and Western blotting using an anti-Myc antibody, or vice versa. Either strategy provided evidence for the co-precipitation of Myc- or Flag-tagged OTR respectively. Biochemical characterization of OTR dimers showed that homodimer formation is not dependent on the establishment of disulfide bonds. The existence of OTR dimers and oligomers at the level of the cell surface was demonstrated by exposing intact living cells to an anti-Flag antibody and analyzing the immunoprecipitate by Western blotting with an anti-Myc antibody. This approach demonstrated furthermore that the presence of receptor oligomers at the cell surface is modulated by ligand in a time-dependent fashion. Finally, we obtained evidence that the OTR is forming oligomeric structures in intact living cells by observing the occurrence of bioluminescence resonance energy transfer in cells co-transfected with OTR constructs bearing at their C-terminus either a Renilla luciferase or the yellow fluorescent protein. Taken together, these data show that the OTR can form homodimers and oligomers in the cell model used and that these oligomers are present at the cell surface.
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Affiliation(s)
- D Devost
- Laboratory of Molecular Endocrinology, McGill University Health Center, Montreal, Quebec, Canada H3A 1A1
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Guimond J, Devost D, Brodeur H, Mader S, Bhat PV. Characterization of the rat RALDH1 promoter. A functional CCAAT and octamer motif are critical for basal promoter activity. Biochim Biophys Acta 2002; 1579:81-91. [PMID: 12427543 DOI: 10.1016/s0167-4781(02)00510-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Retinal dehydrogenase type 1 (RALDH1) catalyzes the oxidation of retinal to retinoic acid (RA), a metabolite of vitamin A important for embryogenesis and tissue differentiation. Rat RALDH1 is expressed to high levels in developing kidney, and in stomach, intestine epithelia. To understand the mechanisms of the transcriptional regulation of rat RALDH1, we cloned a 1360-base pair (bp) 5'-flanking region of RALDH1 gene. Using luciferase reporter constructs transfected into HEK 293 and LLCPK (kidney-derived) cells, basal promoter activity was associated with sequences between -80 and +43. In this minimal promoter region, TATA and CCAAT cis-acting elements as well as SP1, AP1 and octamer (Oct)-binding sites were present. The CCAAT box and Oct-binding site, located between positions -72 and -68 and -56 and -49, respectively, were shown by deletion analysis and site-directed mutation to be critical for promoter activity. Nuclear extracts from kidney cells contain proteins specifically binding the Oct and CCAAT sequences, resulting in the formation of six complexes, while different patterns of complexes were observed with non-kidney cell extracts. Gel shift assays using either single or double mutations of the Oct and CCAAT sequences as well as super shift assays demonstrated single and double occupancy of these two sites by Oct-1 and CBF-A. In addition, unidentified proteins also bound the Oct motif specifically in the absence of CBF-A binding. These results demonstrate specific involvement of Oct and CCAAT-binding proteins in the regulation of RALDH1 gene.
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Affiliation(s)
- Julie Guimond
- Laboratory of Nutrition and Cancer, Centre Hospitalier de l'Universite de Montreal-Hotel-Dieu, Montreal, Quebec, Canada
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Abstract
BACKGROUND An increasing rate of highly-active antiretroviral therapy (HAART)-associated metabolic and morphological abnormalities has been reported in HIV-infected persons. Some of them resemble retinoid-related adverse events, indicating alteration(s) of retinol metabolism or of retinoic acid-mediated signalling. OBJECTIVE To evaluate retinol levels in patients with or without HAART and to assess the effect of antiretroviral agents on retinal dehydrogenase (RALDH), a key enzyme involved in retinoic acid synthesis. DESIGN Plasma retinol levels, measured in six patients receiving HAART and in five others with no antiretroviral therapy, were correlated with levels of serum retinol-binding proteins. We then studied the effects of seven antiretroviral agents on RALDH activity and gene expression in a kidney-derived cell line (LLCPK). RESULTS Plasma retinol levels in patients receiving HAART were decreased in comparison with those not receiving antiretroviral drugs (51 +/- 5 versus 66 +/- 11 microg/dl; P = 0.03), whereas retinol-binding protein levels were increased (68 +/- 18 versus 45 +/- 10 mg/l; P = 0.04). RALDH activity was heightened by ritonavir (24%), indinavir (17%), saquinavir (17%), zalcitabine (14%), delavirdine (12%) and nelfinavir (10%) and decreased (22%) by DMP-450. RALDH gene expression was induced only by indinavir. CONCLUSIONS These data indicate that certain retinoid-like adverse effects in HAART-receiving patients are not due to higher retinol levels. Enhanced RALDH activity or/and gene expression by some protease inhibitors could increase retinoic acid concentrations. Elevated retinoic acid levels might be responsible for retinoid-like or other adverse effects due to alterations in the expression of retinoic acid-responsive genes.
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Affiliation(s)
- E Toma
- Department of Microbiology & Infectious Diseases, Centre hospitalier de l'Université de Montréal, Hôtel-Dieu, Montreal, Quebec, Canada
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Abstract
The autoregulation of prolactin (PRL) secretion in the rat has been demonstrated at both the hypothalamus and the pituitary levels. Studies on the direct negative feedback effect of PRL in the lactotrophs have concentrated on the acute effect on PRL secretion which does not involve change in PRL synthesis. In this study, we have developed a cotransfection assay in somatolactotrophs where we examine the effect of PRL on the transcription of its own gene. We found that oPRL, at physiological concentrations, exerts a strong and specific inhibition of the rPRL gene transcription in PRL-deficient GC cells. This effect is mediated by both the intermediate and the long forms of PRL receptor. The inhibition was also reproduced in GH3 cells, which secretes PRL, by adding exogenous oPRL in the presence of anti-rat PRL antiserum to neutralize endogenous rPRL. Cellular specificity was demonstrated by testing this regulation in non-pituitary cell types where no modulation of the PRL promoter reporter gene could be elicited by PRL, even with cotransfection with the Pit-1 expression vector. Finally, deletions of the rPRL promoter indicate that the full inhibitory effect of PRL requires the same regulatory domains (proximal and distal) that have been described for the other PRL gene regulators. These results strongly suggest the existence of the extra-short loop regulation of the rat PRL at the transcriptional level.
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Affiliation(s)
- D Devost
- Laboratory of Molecular Endocrinology, Centre de Recherche, Hôtel-Dieu du CHUM, University of Montreal, Québec, Canada
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