1
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Reid HM, Maginn M, Perkins CM, Mulvaney EP, Boyce M, Yamamoto T, Kinsella BT. Evaluation of NTP42, a novel thromboxane receptor antagonist, in a first-in-human phase I clinical trial. Front Pharmacol 2023; 14:1296188. [PMID: 38178863 PMCID: PMC10764490 DOI: 10.3389/fphar.2023.1296188] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2023] [Accepted: 12/04/2023] [Indexed: 01/06/2024] Open
Abstract
Background: The thromboxane receptor (TP) antagonist NTP42 is in clinical development for treatment of cardiopulmonary diseases, such as pulmonary arterial hypertension. In this randomized, placebo-controlled Phase I clinical trial, NTP42, administered as the oral formulation NTP42:KVA4, was evaluated for safety, tolerability, pharmacokinetics (PK), and pharmacodynamics (PD) in healthy males. Methods: The first-in-human trial had three Parts: A, single ascending dose (SAD) study with seven groups given 0.25-243 mg NTP42:KVA4 or placebo; B, food effect study where one SAD group (9 mg) was also given NTP42:KVA4 or placebo after a high-fat breakfast; C, multiple ascending dose study with three groups given 15-135 mg NTP42:KVA4 or placebo once-daily for 7 days. Results: Seventy-nine volunteers participated. No serious adverse events occurred, where any drug- or placebo-related adverse events were mild to moderate, with no correlation to NTP42:KVA4 dose. NTP42 was rapidly absorbed, yielding dose proportional increases in exposure after single and repeat dosing. PK confirmed that, with a clearance (T1/2) of 18.7 h, NTP42:KVA4 is suited to once-daily dosing, can be taken with or without food, and does not accumulate on repeat dosing. At doses ≥1 mg, NTP42 led to complete and sustained inhibition of thromboxane-, but not ADP-, induced platelet aggregation ex vivo, with direct correlation between NTP42 exposure and duration of PD effects. Conclusion: Orally administered NTP42:KVA4 was well tolerated, with favorable PK/PD profiles and evidence of specific TP target engagement. These findings support continued clinical development of NTP42:KVA4 for cardiopulmonary or other relevant diseases with unmet needs. Clinical Trial Registration: clinicaltrials.gov, identifier NCT04919863.
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Affiliation(s)
- Helen M. Reid
- ATXA Therapeutics Limited, UCD Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin, Ireland
| | - Mark Maginn
- ATXA Therapeutics Limited, UCD Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin, Ireland
| | - C. Michael Perkins
- ATXA Therapeutics Limited, UCD Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin, Ireland
| | - Eamon P. Mulvaney
- ATXA Therapeutics Limited, UCD Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin, Ireland
| | - Malcolm Boyce
- Hammersmith Medicines Research, London, United Kingdom
| | | | - B. Therese Kinsella
- ATXA Therapeutics Limited, UCD Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin, Ireland
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2
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Ashton AW. Preparing to strike: Acute events in signaling by the serpentine receptor for thromboxane A 2. Pharmacol Ther 2023:108478. [PMID: 37321373 DOI: 10.1016/j.pharmthera.2023.108478] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Revised: 05/31/2023] [Accepted: 06/07/2023] [Indexed: 06/17/2023]
Abstract
Over the last two decades, awareness of the (patho)physiological roles of thromboxane A2 signaling has been greatly extended. From humble beginnings as a short-lived stimulus that activates platelets and causes vasoconstriction to a dichotomous receptor system involving multiple endogenous ligands capable of modifying tissue homeostasis and disease generation in almost every tissue of the body. Thromboxane A2 receptor (TP) signal transduction is associated with the pathogenesis of cancer, atherosclerosis, heart disease, asthma, and host response to parasitic infection amongst others. The two receptors mediating these cellular responses (TPα and TPβ) are derived from a single gene (TBXA2R) through alternative splicing. Recently, knowledge about the mechanism(s) of signal propagation by the two receptors has undergone a revolution in understanding. Not only have the structural relationships associated with G-protein coupling been established but the modulation of that signaling by post-translational modification to the receptor has come sharply into focus. Moreover, the signaling of the receptor unrelated to G-protein coupling has become a burgeoning field of endeavor with over 70 interacting proteins currently identified. These data are reshaping the concept of TP signaling from a mere guanine nucleotide exchange factors for Gα activation to a nexus for the convergence of diverse and poorly characterized signaling pathways. This review summarizes the advances in understanding in TP signaling, and the potential for new growth in a field that after almost 50 years is finally coming of age.
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Affiliation(s)
- Anthony W Ashton
- Division of Cardiovascular Medicine, Lankenau Institute for Medical Research, Rm 128, 100 E Lancaster Ave, Wynnewood, PA 19096, USA; Division of Perinatal Research, Kolling Institute of Medical Research, Faculty of Medicine and Health, University of Sydney, St Leonards, NSW 2065, Australia.
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3
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Biringer RG. A Review of Prostanoid Receptors: Expression, Characterization, Regulation, and Mechanism of Action. J Cell Commun Signal 2021; 15:155-184. [PMID: 32970276 PMCID: PMC7991060 DOI: 10.1007/s12079-020-00585-0] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2020] [Accepted: 09/15/2020] [Indexed: 12/22/2022] Open
Abstract
Prostaglandin signaling controls a wide range of biological processes from blood pressure homeostasis to inflammation and resolution thereof to the perception of pain to cell survival. Disruption of normal prostanoid signaling is implicated in numerous disease states. Prostaglandin signaling is facilitated by G-protein-coupled, prostanoid-specific receptors and the array of associated G-proteins. This review focuses on the expression, characterization, regulation, and mechanism of action of prostanoid receptors with particular emphasis on human isoforms.
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Affiliation(s)
- Roger G Biringer
- College of Osteopathic Medicine, Lake Erie College of Osteopathic Medicine, 5000 Lakewood Ranch Blvd, Bradenton, FL, 34211, USA.
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4
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Putman AK, Contreras GA, Sordillo LM. Isoprostanes in Veterinary Medicine: Beyond a Biomarker. Antioxidants (Basel) 2021; 10:antiox10020145. [PMID: 33498324 PMCID: PMC7909258 DOI: 10.3390/antiox10020145] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Revised: 01/16/2021] [Accepted: 01/18/2021] [Indexed: 11/21/2022] Open
Abstract
Oxidative stress has been associated with many pathologies, in both human and animal medicine. Damage to tissue components such as lipids is a defining feature of oxidative stress and can lead to the generation of many oxidized products, including isoprostanes (IsoP). First recognized in the early 1990s, IsoP are formed in numerous biological fluids and tissues, chemically stable, and easily measured by noninvasive means. Additionally, IsoP are highly specific indicators of lipid peroxidation and thereby are regarded as excellent biomarkers of oxidative stress. Although there have been many advancements in the detection and use of IsoP as a biomarker, there is still a paucity of knowledge regarding the biological activity of these molecules and their potential roles in pathology of oxidative stress. Furthermore, the use of IsoP has been limited in veterinary species thus far and represents an avenue of opportunity for clinical applications in veterinary practice. Examples of clinical applications of IsoP in veterinary medicine include use as a novel biomarker to guide treatment recommendations or as a target to mitigate inflammatory processes. This review will discuss the history, biosynthesis, measurement, use as a biomarker, and biological action of IsoP, particularly in the context of veterinary medicine.
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5
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Lismont E, Verbakel L, Vogel E, Corbisier J, Degroot GN, Verdonck R, Verlinden H, Marchal E, Springael JY, Vanden Broeck J. Can BRET-based biosensors be used to characterize G-protein mediated signaling pathways of an insect GPCR, the Schistocerca gregaria CRF-related diuretic hormone receptor? INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2020; 122:103392. [PMID: 32387240 DOI: 10.1016/j.ibmb.2020.103392] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Revised: 04/01/2020] [Accepted: 04/19/2020] [Indexed: 05/26/2023]
Abstract
G protein-coupled receptors (GPCRs) are membrane-bound receptors that are considered prime candidates for the development of novel insect pest management strategies. However, the molecular signaling properties of insect GPCRs remain poorly understood. In fact, most studies on insect GPCR signaling are limited to analysis of fluctuations in the secondary messenger molecules calcium (Ca2+) and/or cyclic adenosine monophosphate (cAMP). In the current study, we characterized a corticotropin-releasing factor-related diuretic hormone (CRF-DH) receptor of the desert locust, Schistocerca gregaria. This Schgr-CRF-DHR is mainly expressed in the nervous system and in brain-associated endocrine organs. The neuropeptide Schgr-CRF-DH induced Ca2+-dependent aequorin-based bioluminescent responses in CHO cells co-expressing this receptor with the promiscuous Gα16 protein. Furthermore, when co-expressed with the cAMP-dependent bioluminescence resonance energy transfer (BRET)-based CAMYEL biosensor in HEK293T cells, this receptor elicited dose-dependent agonist-induced responses with an EC50 in the nanomolar range (4.02 nM). In addition, we tested if vertebrate BRET-based G protein biosensors, can also be used to detect direct Gα protein subunit activation by an insect GPCR. Therefore, we analyzed ten different human BRET-based G protein biosensors, representing members of all four Gα protein subfamilies; Gαs, Gαi/o, Gαq/11 and Gα12/13. Our data demonstrate that stimulation of Schgr-CRF-DHR by Schgr-CRF-DH can dose-dependently activate Gαi/o and Gαs biosensors, while no significant effects were observed with the Gαq/11 and Gα12/13 biosensors. Our study paves the way for future biosensor-based studies to analyze the signaling properties of insect GPCRs in both fundamental science and applied research contexts.
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Affiliation(s)
- Els Lismont
- Molecular Developmental Physiology and Signal Transduction, KU Leuven, Naamsestraat 59, P.O. Box 02465, B-3000, Leuven, Belgium
| | - Lina Verbakel
- Molecular Developmental Physiology and Signal Transduction, KU Leuven, Naamsestraat 59, P.O. Box 02465, B-3000, Leuven, Belgium.
| | - Elise Vogel
- Molecular Developmental Physiology and Signal Transduction, KU Leuven, Naamsestraat 59, P.O. Box 02465, B-3000, Leuven, Belgium
| | | | | | - Rik Verdonck
- Molecular Developmental Physiology and Signal Transduction, KU Leuven, Naamsestraat 59, P.O. Box 02465, B-3000, Leuven, Belgium
| | - Heleen Verlinden
- Molecular Developmental Physiology and Signal Transduction, KU Leuven, Naamsestraat 59, P.O. Box 02465, B-3000, Leuven, Belgium
| | - Elisabeth Marchal
- Molecular Developmental Physiology and Signal Transduction, KU Leuven, Naamsestraat 59, P.O. Box 02465, B-3000, Leuven, Belgium; Imec, Kapeldreef 75, B-3001, Leuven, Belgium
| | - Jean-Yves Springael
- Institut de Recherche Interdisciplinaire en Biologie Humaine et Moléculaire (IRIBHM) Université Libre de Bruxelles (ULB), Campus Erasme, 808 Route de Lennik, B-1070, Brussels, Belgium
| | - Jozef Vanden Broeck
- Molecular Developmental Physiology and Signal Transduction, KU Leuven, Naamsestraat 59, P.O. Box 02465, B-3000, Leuven, Belgium
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6
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Mulvaney EP, Reid HM, Bialesova L, Bouchard A, Salvail D, Kinsella BT. NTP42, a novel antagonist of the thromboxane receptor, attenuates experimentally induced pulmonary arterial hypertension. BMC Pulm Med 2020; 20:85. [PMID: 32252727 PMCID: PMC7132963 DOI: 10.1186/s12890-020-1113-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2019] [Accepted: 03/12/2020] [Indexed: 02/25/2023] Open
Abstract
BACKGROUND NTP42 is a novel antagonist of the thromboxane prostanoid receptor (TP), currently in development for the treatment of pulmonary arterial hypertension (PAH). PAH is a devastating disease with multiple pathophysiological hallmarks including excessive pulmonary vasoconstriction, vascular remodelling, inflammation, fibrosis, in situ thrombosis and right ventricular hypertrophy. Signalling through the TP, thromboxane (TX) A2 is a potent vasoconstrictor and mediator of platelet aggregation. It is also a pro-mitogenic, pro-inflammatory and pro-fibrotic agent. Moreover, the TP also mediates the adverse actions of the isoprostane 8-iso-prostaglandin F2α, a free-radical-derived product of arachidonic acid produced in abundance during oxidative injury. Mechanistically, TP antagonists should treat most of the hallmarks of PAH, including inhibiting the excessive vasoconstriction and pulmonary artery remodelling, in situ thrombosis, inflammation and fibrosis. This study aimed to investigate the efficacy of NTP42 in the monocrotaline (MCT)-induced PAH rat model, alongside current standard-of-care drugs. METHODS PAH was induced by subcutaneous injection of 60 mg/kg MCT in male Wistar-Kyoto rats. Animals were assigned into groups: 1. 'No MCT'; 2. 'MCT Only'; 3. MCT + NTP42 (0.25 mg/kg BID); 4. MCT + Sildenafil (50 mg/kg BID), and 5. MCT + Selexipag (1 mg/kg BID), where 28-day drug treatment was initiated within 24 h post-MCT. RESULTS From haemodynamic assessments, NTP42 reduced the MCT-induced PAH, including mean pulmonary arterial pressure (mPAP) and right systolic ventricular pressure (RSVP), being at least comparable to the standard-of-care drugs Sildenafil or Selexipag in bringing about these effects. Moreover, NTP42 was superior to Sildenafil and Selexipag in significantly reducing pulmonary vascular remodelling, inflammatory mast cell infiltration and fibrosis in MCT-treated animals. CONCLUSIONS These findings suggest that NTP42 and antagonism of the TP signalling pathway have a relevant role in alleviating the pathophysiology of PAH, representing a novel therapeutic target with marked benefits over existing standard-of-care therapies.
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Affiliation(s)
- Eamon P Mulvaney
- ATXA Therapeutics Limited, UCD Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin 4, Ireland
| | - Helen M Reid
- ATXA Therapeutics Limited, UCD Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin 4, Ireland.,UCD School of Biomolecular and Biomedical Sciences, UCD Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin 4, Ireland
| | - Lucia Bialesova
- ATXA Therapeutics Limited, UCD Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin 4, Ireland
| | - Annie Bouchard
- IPS Therapeutique Inc., 3035 Boulevard Industriel, Sherbrooke, QC, J1L 2T9, Canada
| | - Dany Salvail
- IPS Therapeutique Inc., 3035 Boulevard Industriel, Sherbrooke, QC, J1L 2T9, Canada
| | - B Therese Kinsella
- ATXA Therapeutics Limited, UCD Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin 4, Ireland. .,UCD School of Biomolecular and Biomedical Sciences, UCD Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin 4, Ireland.
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7
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Yan H, Zhang MZ, Wong G, Liu L, Kwok YSS, Kuang SJ, Yang H, Rao F, Li X, Mai LP, Lin QX, Yang M, Zhang QH, Deng CY. Mechanisms of U46619-induced contraction in mouse intrarenal artery. Clin Exp Pharmacol Physiol 2019; 46:643-651. [PMID: 30907443 DOI: 10.1111/1440-1681.13087] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2018] [Revised: 03/15/2019] [Accepted: 03/19/2019] [Indexed: 11/27/2022]
Abstract
Thromboxane A2 (TXA2 ) has been implicated in the pathogenesis of vascular complications, but the underlying mechanism remains unclear. The contraction of renal arterial rings in mice was measured by a Multi Myograph System. The intracellular calcium concentration ([Ca2+ ]i ) in vascular smooth muscle cells (VSMCs) was obtained by using a fluo-4/AM dye and a confocal laser scanning microscopy. The results show that the U46619-induced vasoconstriction of renal artery was completely blocked by a TXA2 receptor antagonist GR32191, significantly inhibited by a selective phospholipase C (PI-PLC) inhibitor U73122 at 10 μmol/L and partially inhibited by a Phosphatidylcholine - specific phospholipase C (PC-PLC) inhibitor D609 at 50 μmol/L. Moreover, the U46619-induced vasoconstriction was inhibited by a general protein kinase C (PKC) inhibitor chelerythrine at 10 μmol/L, and a selective PKCδ inhibitor rottlerin at 10 μmol/L. In addition, the PKC-induced vasoconstriction was partially inhibited by a Rho-kinase inhibitor Y-27632 at 10 μmol/L and was further completely inhibited together with a putative IP3 receptor antagonist and store-operated Ca2+ (SOC) entry inhibitor 2-APB at 100 μmol/L. On the other hand, U46619-induced vasoconstriction was partially inhibited by L-type calcium channel (Cav1.2) inhibitor nifedipine at 1 μmol/L and 2-APB at 50 and 100 μmol/L. Last, U46619-induced vasoconstriction was partially inhibited by a cell membrane Ca2+ activated C1- channel blocker 5-Nitro-2-(3-phenylpropylamino) benzoic acid (NPPB) at 50 and 100 μmol/L. Our results suggest that the U46619-induced contraction of mouse intrarenal arteries is mediated by Cav1.2 and SOC channel, through the activation of thromboxane-prostanoid receptors and its downstream signaling pathway.
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Affiliation(s)
- Hong Yan
- Department of Cardiology, Guangdong Cardiovascular Institute, Guangzhou, China.,Guangdong Academy of Medical Sciences, Guangdong Provincial People's Hospital, Guangzhou, China
| | - Meng-Zhen Zhang
- Department of Cardiology, Guangdong Cardiovascular Institute, Guangzhou, China.,Guangdong Academy of Medical Sciences, Guangdong Provincial People's Hospital, Guangzhou, China.,Guangdong Provincial Key Laboratory of Clinical Pharmacology, Guangdong Academy of Medical Sciences, Guangdong Provincial People's Hospital, Guangzhou, China
| | - Gordon Wong
- Department of Cardiology, Guangdong Cardiovascular Institute, Guangzhou, China.,Guangdong Academy of Medical Sciences, Guangdong Provincial People's Hospital, Guangzhou, China.,Guangdong Provincial Key Laboratory of Clinical Pharmacology, Guangdong Academy of Medical Sciences, Guangdong Provincial People's Hospital, Guangzhou, China
| | - Lin Liu
- Department of Cardiology, Guangdong Cardiovascular Institute, Guangzhou, China.,Guangdong Academy of Medical Sciences, Guangdong Provincial People's Hospital, Guangzhou, China.,Guangdong Provincial Key Laboratory of Clinical Pharmacology, Guangdong Academy of Medical Sciences, Guangdong Provincial People's Hospital, Guangzhou, China
| | - Yat Sze Shelia Kwok
- Department of Cardiology, Guangdong Cardiovascular Institute, Guangzhou, China.,Guangdong Academy of Medical Sciences, Guangdong Provincial People's Hospital, Guangzhou, China.,Guangdong Provincial Key Laboratory of Clinical Pharmacology, Guangdong Academy of Medical Sciences, Guangdong Provincial People's Hospital, Guangzhou, China
| | - Su-Juan Kuang
- Department of Cardiology, Guangdong Cardiovascular Institute, Guangzhou, China.,Guangdong Academy of Medical Sciences, Guangdong Provincial People's Hospital, Guangzhou, China.,Guangdong Provincial Key Laboratory of Clinical Pharmacology, Guangdong Academy of Medical Sciences, Guangdong Provincial People's Hospital, Guangzhou, China
| | - Hui Yang
- Department of Cardiology, Guangdong Cardiovascular Institute, Guangzhou, China.,Guangdong Academy of Medical Sciences, Guangdong Provincial People's Hospital, Guangzhou, China.,Guangdong Provincial Key Laboratory of Clinical Pharmacology, Guangdong Academy of Medical Sciences, Guangdong Provincial People's Hospital, Guangzhou, China
| | - Fang Rao
- Department of Cardiology, Guangdong Cardiovascular Institute, Guangzhou, China.,Guangdong Academy of Medical Sciences, Guangdong Provincial People's Hospital, Guangzhou, China.,Guangdong Provincial Key Laboratory of Clinical Pharmacology, Guangdong Academy of Medical Sciences, Guangdong Provincial People's Hospital, Guangzhou, China
| | - Xin Li
- Department of Cardiology, Guangdong Cardiovascular Institute, Guangzhou, China.,Guangdong Academy of Medical Sciences, Guangdong Provincial People's Hospital, Guangzhou, China.,Guangdong Provincial Key Laboratory of Clinical Pharmacology, Guangdong Academy of Medical Sciences, Guangdong Provincial People's Hospital, Guangzhou, China
| | - Li-Ping Mai
- Department of Cardiology, Guangdong Cardiovascular Institute, Guangzhou, China.,Guangdong Academy of Medical Sciences, Guangdong Provincial People's Hospital, Guangzhou, China.,Guangdong Provincial Key Laboratory of Clinical Pharmacology, Guangdong Academy of Medical Sciences, Guangdong Provincial People's Hospital, Guangzhou, China
| | - Qiu-Xiong Lin
- Department of Cardiology, Guangdong Cardiovascular Institute, Guangzhou, China.,Guangdong Academy of Medical Sciences, Guangdong Provincial People's Hospital, Guangzhou, China.,Guangdong Provincial Key Laboratory of Clinical Pharmacology, Guangdong Academy of Medical Sciences, Guangdong Provincial People's Hospital, Guangzhou, China
| | - Min Yang
- Department of Cardiology, Guangdong Cardiovascular Institute, Guangzhou, China.,Guangdong Academy of Medical Sciences, Guangdong Provincial People's Hospital, Guangzhou, China.,Guangdong Provincial Key Laboratory of Clinical Pharmacology, Guangdong Academy of Medical Sciences, Guangdong Provincial People's Hospital, Guangzhou, China
| | - Qian-Huan Zhang
- Department of Cardiology, Guangdong Cardiovascular Institute, Guangzhou, China.,Guangdong Academy of Medical Sciences, Guangdong Provincial People's Hospital, Guangzhou, China.,Guangdong Provincial Key Laboratory of Clinical Pharmacology, Guangdong Academy of Medical Sciences, Guangdong Provincial People's Hospital, Guangzhou, China
| | - Chun-Yu Deng
- Department of Cardiology, Guangdong Cardiovascular Institute, Guangzhou, China.,Guangdong Academy of Medical Sciences, Guangdong Provincial People's Hospital, Guangzhou, China.,Guangdong Provincial Key Laboratory of Clinical Pharmacology, Guangdong Academy of Medical Sciences, Guangdong Provincial People's Hospital, Guangzhou, China
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8
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Rovati GE, Capra V, Shaw VS, Malik RU, Sivaramakrishnan S, Neubig RR. The DRY motif and the four corners of the cubic ternary complex model. Cell Signal 2017; 35:16-23. [PMID: 28347873 DOI: 10.1016/j.cellsig.2017.03.020] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2017] [Accepted: 03/24/2017] [Indexed: 12/14/2022]
Abstract
Recent structural data on GPCRs using a variety of spectroscopic approaches suggest that GPCRs adopt a dynamic conformational landscape, with ligands stabilizing subsets of these states to activate one or more downstream signaling effectors. A key outstanding question posed by this emerging dynamic structural model of GPCRs is what states, active, inactive, or intermediate are captured by the numerous crystal structures of GPCRs complexed with a variety of agonists, partial agonists, and antagonists. In the early nineties the discovery of inverse agonists and constitutive activity led to the idea that the active receptor state (R⁎) is an intrinsic property of the receptor itself rather than of the RG complex, eventually leading to the formulation of the cubic ternary complex model (CTC). Here, by a careful analysis of a series of data obtained with a number of mutants of the highly conserved E/DRY motif, we show evidences for the existence of all the receptor states theorized by the CTC, four 'uncoupled (R, R⁎ and HR and HR⁎), and, consequently four 'coupled' (RG, R⁎G, HRG and HR⁎G). The E/DRY motif located at the cytosolic end of transmembrane helix III of Class A GPCRs has been widely studied and analyzed because it forms a network of interactions believed to lock receptors in the inactive conformation (R), and, thus, to play a key role in receptor activation. Our conclusions are supported by recent crystal and NMR spectra, as well as by results obtained with two prototypical GPCRs using a new FRET technology that de-couples G protein binding to the receptor from signal transduction. Thus, despite its complexity and limitations, we propose that the CTC is a useful framework to reconcile pharmacological, biochemical and structural data.
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Affiliation(s)
- G Enrico Rovati
- Department of Pharmacological and Biomolecular Sciences, University of Milan, Milano, Italy.
| | - Valérie Capra
- Department of Pharmacological and Biomolecular Sciences, University of Milan, Milano, Italy; Department of Health Science, University of Milan, Milano, Italy.
| | - Vincent S Shaw
- Department of Pharmacology & Toxicology, Michigan State University, East Lansing, MI, USA.
| | - Rabia U Malik
- Department of Genetics, Cell Biology & Development, College of Biological Sciences, University of Minnesota Twin Cities, Minneapolis, MN, USA.
| | - Sivaraj Sivaramakrishnan
- Department of Genetics, Cell Biology & Development, College of Biological Sciences, University of Minnesota Twin Cities, Minneapolis, MN, USA.
| | - Richard R Neubig
- Department of Pharmacology & Toxicology, Michigan State University, East Lansing, MI, USA.
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9
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Capra V, Mauri M, Guzzi F, Busnelli M, Accomazzo MR, Gaussem P, Nisar SP, Mundell SJ, Parenti M, Rovati GE. Impaired thromboxane receptor dimerization reduces signaling efficiency: A potential mechanism for reduced platelet function in vivo. Biochem Pharmacol 2016; 124:43-56. [PMID: 27845050 DOI: 10.1016/j.bcp.2016.11.010] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Accepted: 11/10/2016] [Indexed: 12/16/2022]
Abstract
Thromboxane A2 is a potent mediator of inflammation and platelet aggregation exerting its effects through the activation of a G protein-coupled receptor (GPCR), termed TP. Although the existence of dimers/oligomers in Class A GPCRs is widely accepted, their functional significance still remains controversial. Recently, we have shown that TPα and TPβ homo-/hetero-dimers interact through an interface of residues in transmembrane domain 1 (TM1) whose disruption impairs dimer formation. Here, biochemical and pharmacological characterization of this dimer deficient mutant (DDM) in living cells indicates a significant impairment in its response to agonists. Interestingly, two single loss-of-function TPα variants, namely W29C and N42S recently identified in two heterozygous patients affected by bleeding disorders, match some of the residues mutated in our DDM. These two naturally occurring variants display a reduced potency to TP agonists and are characterized by impaired dimer formation in transfected HEK-293T cells. These findings provide proofs that lack of homo-dimer formation is a crucial process for reduced TPα function in vivo, and might represent one molecular mechanism through which platelet TPα receptor dysfunction affects the patient(s) carrying these mutations.
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Key Words
- (Z)-7-[(1R,2R,3R,4S)-3-[[2-(phenylcarbamoyl)hydrazinyl]methyl]-7-oxabicyclo[2.2.1]heptan-2-yl]hept-5-enoic acid
- (Z)-7-[(1S,2S,3R,4R)-3-[(E,3S)-3-hydroxyoct-1-enyl]-5-oxabicyclo[2.2.1]heptan-2-yl]hept-5-enoic acid
- (Z)-7-[(1S,2S,3S,4R)-3-[(E,3R)-3-hydroxy-4-(4-iodophenoxy)but-1-enyl]-7-oxabicyclo[2.2.1]heptan-2-yl]hept-5-enoic acid
- (Z)-7-[(1S,3R,4R,5S)-3-[(E,3R)-3-hydroxyoct-1-enyl]-6,6-dimethyl-4-bicyclo[3.1.1]heptanyl]hept-5-enoic acid
- 3-[(3R)-3-[(4-fluorophenyl)sulfonylamino]-1,2,3,4-tetrahydrocarbazol-9-yl]propanoic acid
- Eicosanoids
- G protein coupled receptors
- I-BOP (PubChem CID: 51015454)
- Pinane Thromboxane A2 (PTA2) (PubChem CID: 25834471)
- Platelets
- Ramatroban (PubChem CID: 123879)
- Receptor dimer
- SQ29,548 (PubChem CID: 6437074)
- Signal transduction
- Thromboxane A(2)
- U46619 (PubChem CID: 5311493)
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Affiliation(s)
- Valérie Capra
- Department of Pharmacological and Biomolecular Sciences, University of Milan, Milano, Italy; Department of Health Science, University of Milan, Milano, Italy.
| | - Mario Mauri
- Department of Medicine and Surgery, University of Milano-Bicocca, Monza, Italy.
| | - Francesca Guzzi
- Department of Medicine and Surgery, University of Milano-Bicocca, Monza, Italy.
| | - Marta Busnelli
- CNR, Institute of Neuroscience, University of Milan, Milan, Italy; Department of Medical Biotechnology and Translational Medicine, University of Milan, Milan, Italy.
| | - Maria Rosa Accomazzo
- Department of Pharmacological and Biomolecular Sciences, University of Milan, Milano, Italy.
| | - Pascale Gaussem
- Inserm UMR-S1140, Faculte' de Pharmacie, Université Paris Descartes, Sorbonne Paris Cité, Paris and AP-HP, Hopital Européen Georges Pompidou, Service d'Hématologie Biologique, Paris, France.
| | - Shaista P Nisar
- School of Physiology and Pharmacology, University of Bristol, Bristol BS8 1TD, UK.
| | - Stuart J Mundell
- School of Physiology and Pharmacology, University of Bristol, Bristol BS8 1TD, UK.
| | - Marco Parenti
- Department of Medicine and Surgery, University of Milano-Bicocca, Monza, Italy.
| | - G Enrico Rovati
- Department of Pharmacological and Biomolecular Sciences, University of Milan, Milano, Italy.
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Hoxha M, Buccellati C, Capra V, Garella D, Cena C, Rolando B, Fruttero R, Carnevali S, Sala A, Rovati G, Bertinaria M. In vitro pharmacological evaluation of multitarget agents for thromboxane prostanoid receptor antagonism and COX-2 inhibition. Pharmacol Res 2016; 103:132-43. [DOI: 10.1016/j.phrs.2015.11.012] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/30/2015] [Accepted: 11/15/2015] [Indexed: 11/29/2022]
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12
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Rovati GE, Capra V. The DRY motif at work: the P2Y12 receptor case. J Thromb Haemost 2014; 12:713-5. [PMID: 24589132 DOI: 10.1111/jth.12543] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2014] [Accepted: 02/14/2014] [Indexed: 10/25/2022]
Affiliation(s)
- G E Rovati
- Department of Pharmacological and Biomolecular Sciences, Laboratory of Molecular Pharmacology, Milan, Italy
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