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Vandenberghe LTM, Heindryckx B, Smits K, Popovic M, Szymanska K, Bonte D, Peelman L, Deforce D, De Sutter P, Van Soom A, De Schauwer C. Intracellular localisation of platelet-activating factor during mammalian embryo development in vitro: a comparison of cattle, mouse and human. Reprod Fertil Dev 2018; 31:658-670. [PMID: 30458920 DOI: 10.1071/rd18146] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2018] [Accepted: 10/05/2018] [Indexed: 11/23/2022] Open
Abstract
Platelet-activating factor (PAF) is a well-known marker for embryo quality and viability. For the first time, we describe an intracellular localisation of PAF in oocytes and embryos of cattle, mice and humans. We showed that PAF is represented in the nucleus, a signal that was lost upon nuclear envelope breakdown. This process was confirmed by treating the embryos with nocodazole, a spindle-disrupting agent that, as such, arrests the embryo in mitosis, and by microinjecting a PAF-specific antibody in bovine MII oocytes. The latter resulted in the absence of nuclear PAF in the pronuclei of the zygote and reduced further developmental potential. Previous research indicates that PAF is released and taken up from the culture medium by preimplantation embryos invitro, in which bovine serum albumin (BSA) serves as a crucial carrier molecule. In the present study we demonstrated that nuclear PAF does not originate from an extracellular source because embryos cultured in polyvinylpyrrolidone or BSA showed similar levels of PAF in their nuclei. Instead, our experiments indicate that cytosolic phospholipase A2 (cPLA2) is likely to be involved in the intracellular production of PAF, because treatment with arachidonyl trifluoromethyl ketone (AACOCF3), a specific cPLA2 inhibitor, clearly lowered PAF levels in the nuclei of bovine embryos.
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Affiliation(s)
- L T M Vandenberghe
- Department of Reproduction, Obstetrics and Herd Health, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, 9820 Merelbeke, Belgium
| | - B Heindryckx
- Ghent-Fertility and Stem cell Team (G-FaST), Department for Reproductive Medicine, Ghent University Hospital, De Pintelaan 185, 9000 Ghent, Belgium
| | - K Smits
- Department of Reproduction, Obstetrics and Herd Health, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, 9820 Merelbeke, Belgium
| | - M Popovic
- Ghent-Fertility and Stem cell Team (G-FaST), Department for Reproductive Medicine, Ghent University Hospital, De Pintelaan 185, 9000 Ghent, Belgium
| | - K Szymanska
- Physiology Group, Department of Basic Medical Sciences, Ghent University, De Pintelaan 185, 9000 Ghent, Belgium
| | - D Bonte
- Ghent-Fertility and Stem cell Team (G-FaST), Department for Reproductive Medicine, Ghent University Hospital, De Pintelaan 185, 9000 Ghent, Belgium
| | - L Peelman
- Department of Nutrition, Genetics and Ethology, Faculty of Veterinary Medicine, Ghent University, Heidestraat 19, 9820 Merelbeke, Belgium
| | - D Deforce
- Laboratory of Pharmaceutical Biotechnology, Ghent University, Harelbekestraat 72, 9000 Ghent, Belgium
| | - P De Sutter
- Ghent-Fertility and Stem cell Team (G-FaST), Department for Reproductive Medicine, Ghent University Hospital, De Pintelaan 185, 9000 Ghent, Belgium
| | - A Van Soom
- Department of Reproduction, Obstetrics and Herd Health, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, 9820 Merelbeke, Belgium
| | - C De Schauwer
- Department of Reproduction, Obstetrics and Herd Health, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, 9820 Merelbeke, Belgium
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Barton M, Filardo EJ, Lolait SJ, Thomas P, Maggiolini M, Prossnitz ER. Twenty years of the G protein-coupled estrogen receptor GPER: Historical and personal perspectives. J Steroid Biochem Mol Biol 2018; 176:4-15. [PMID: 28347854 PMCID: PMC5716468 DOI: 10.1016/j.jsbmb.2017.03.021] [Citation(s) in RCA: 148] [Impact Index Per Article: 24.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/30/2017] [Revised: 03/22/2017] [Accepted: 03/23/2017] [Indexed: 12/24/2022]
Abstract
Estrogens play a critical role in many aspects of physiology, particularly female reproductive function, but also in pathophysiology, and are associated with protection from numerous diseases in premenopausal women. Steroids and the effects of estrogen have been known for ∼90 years, with the first evidence for a receptor for estrogen presented ∼50 years ago. The original ancestral steroid receptor, extending back into evolution more than 500 million years, was likely an estrogen receptor, whereas G protein-coupled receptors (GPCRs) trace their origins back into history more than one billion years. The classical estrogen receptors (ERα and ERβ) are ligand-activated transcription factors that confer estrogen sensitivity upon many genes. It was soon apparent that these, or novel receptors may also be responsible for the "rapid"/"non-genomic" membrane-associated effects of estrogen. The identification of an orphan GPCR (GPR30, published in 1996) opened a new field of research with the description in 2000 that GPR30 expression is required for rapid estrogen signaling. In 2005-2006, the field was greatly stimulated by two studies that described the binding of estrogen to GPR30-expressing cell membranes, followed by the identification of a GPR30-selective agonist (that lacked binding and activity towards ERα and ERβ). Renamed GPER (G protein-coupled estrogen receptor) by IUPHAR in 2007, the total number of articles in PubMed related to this receptor recently surpassed 1000. In this article, the authors present personal perspectives on how they became involved in the discovery and/or advancement of GPER research. These areas include non-genomic effects on vascular tone, receptor cloning, molecular and cellular biology, signal transduction mechanisms and pharmacology of GPER, highlighting the roles of GPER and GPER-selective compounds in diseases such as obesity, diabetes, and cancer and the obligatory role of GPER in propagating cardiovascular aging, arterial hypertension and heart failure through the stimulation of Nox expression.
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Affiliation(s)
- Matthias Barton
- Molecular Internal Medicine, University of Zürich, 8057 Zürich, Switzerland.
| | - Edward J Filardo
- Rhode Island Hospital, Brown University, Providence, RI 02903, USA
| | - Stephen J Lolait
- Henry Wellcome Laboratories for Integrative Neuroscience and Endocrinology, School of Clinical Sciences, University of Bristol, Bristol, UK
| | - Peter Thomas
- Marine Science Institute, University of Texas at Austin, Port Aransas, TX 78373, USA
| | - Marcello Maggiolini
- Department of Pharmacy, Health and Nutritional Sciences, University of Calabria, Rende, Italy
| | - Eric R Prossnitz
- Department of Internal Medicine, University of New Mexico Health Sciences Center and University of New Mexico Comprehensive Cancer Center, Albuquerque, NM 87131, USA.
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Joyal JS, Gantner ML, Smith LEH. Retinal energy demands control vascular supply of the retina in development and disease: The role of neuronal lipid and glucose metabolism. Prog Retin Eye Res 2017; 64:131-156. [PMID: 29175509 DOI: 10.1016/j.preteyeres.2017.11.002] [Citation(s) in RCA: 91] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2017] [Revised: 11/11/2017] [Accepted: 11/15/2017] [Indexed: 12/15/2022]
Affiliation(s)
- Jean-Sébastien Joyal
- Department of Pediatrics, Pharmacology and Ophthalmology, CHU Sainte-Justine Research Center, Université de Montréal, Montreal, Qc, Canada; Department of Pharmacology and Therapeutics, McGill University, Montreal, Qc, Canada.
| | - Marin L Gantner
- The Lowy Medical Research Institute, La Jolla, United States
| | - Lois E H Smith
- Department of Ophthalmology, Harvard Medical School, Boston Children's Hospital, 300 Longwood Avenue, Boston MA 02115, United States.
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A Review on Platelet Activating Factor Inhibitors: Could a New Class of Potent Metal-Based Anti-Inflammatory Drugs Induce Anticancer Properties? Bioinorg Chem Appl 2017; 2017:6947034. [PMID: 28458618 PMCID: PMC5387815 DOI: 10.1155/2017/6947034] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2016] [Accepted: 02/27/2017] [Indexed: 12/12/2022] Open
Abstract
In this minireview, we refer to recent results as far as the Platelet Activating Factor (PAF) inhibitors are concerned. At first, results of organic compounds (natural and synthetic ones and specific and nonspecific) as inhibitors of PAF are reported. Emphasis is given on recent results about a new class of the so-called metal-based inhibitors of PAF. A small library of 30 metal complexes has been thus created; their anti-inflammatory activity has been further evaluated owing to their inhibitory effect against PAF in washed rabbit platelets (WRPs). In addition, emphasis has also been placed on the identification of preliminary structure-activity relationships for the different classes of metal-based inhibitors.
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Cattaneo F, Parisi M, Fioretti T, Sarnataro D, Esposito G, Ammendola R. Nuclear localization of Formyl-Peptide Receptor 2 in human cancer cells. Arch Biochem Biophys 2016; 603:10-9. [PMID: 27177968 DOI: 10.1016/j.abb.2016.05.006] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2016] [Revised: 05/06/2016] [Accepted: 05/06/2016] [Indexed: 12/20/2022]
Abstract
Current models of G protein-coupled receptors (GPCRs) signaling describe binding of external agonists to cell surface receptors which, in turn, trigger several biological responses. New paradigms indicate that GPCRs localize to and signal at the nucleus, thus regulating distinct signaling cascades. The formyl-peptide receptor FPR2 belongs to the GPCR super-family and is coupled to PTX-sensitive Gi proteins. We show by western blot analysis, immunofluorescence experiments and radioligand binding assays that FPR2 is expressed at nuclear level in CaLu-6 and AGS cells. Nuclear FPR2 is a functional receptor, since it participates in intra-nuclear signaling, as assessed by decreased G protein-FPR2 association and enhanced ERK2, c-Jun and c-Myc phosphorylation upon stimulation of intact nuclei with the FPR2 agonist, WKYMVm. We analyzed FPR2 sequence for the search of a nuclear localization sequence (NLS) and we found a stretch of basic aminoacids (227-KIHKK-231) in the third cytoplasmic loop of the receptor. We performed single (K230A) and multiple (H229A/K230A/K231A) mutagenesis of NLS. The constructs were individually overexpressed in HEK293 cells and immunofluorescence and western blot analysis showed that nuclear localization or translocation of FPR2 depends on the integrity of the H(229) and K(231) residues within the NLS.
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Affiliation(s)
- Fabio Cattaneo
- Department of Molecular Medicine and Medical Biotechnology, School of Medicine, University of Naples Federico II, Via S. Pansini 5, Naples 80131, Italy
| | - Melania Parisi
- Department of Molecular Medicine and Medical Biotechnology, School of Medicine, University of Naples Federico II, Via S. Pansini 5, Naples 80131, Italy
| | - Tiziana Fioretti
- Department of Molecular Medicine and Medical Biotechnology, School of Medicine, University of Naples Federico II, Via S. Pansini 5, Naples 80131, Italy; IRCCS SDN, Via E. Gianturco 113, Naples 80143, Italy
| | - Daniela Sarnataro
- Department of Molecular Medicine and Medical Biotechnology, School of Medicine, University of Naples Federico II, Via S. Pansini 5, Naples 80131, Italy; CEINGE-Biotecnologie Avanzate s.c.a.r.l., Via G. Salvatore 486, Naples 80145, Italy
| | - Gabriella Esposito
- Department of Molecular Medicine and Medical Biotechnology, School of Medicine, University of Naples Federico II, Via S. Pansini 5, Naples 80131, Italy; CEINGE-Biotecnologie Avanzate s.c.a.r.l., Via G. Salvatore 486, Naples 80145, Italy
| | - Rosario Ammendola
- Department of Molecular Medicine and Medical Biotechnology, School of Medicine, University of Naples Federico II, Via S. Pansini 5, Naples 80131, Italy.
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Pupo M, Vivacqua A, Perrotta I, Pisano A, Aquila S, Abonante S, Gasperi-Campani A, Pezzi V, Maggiolini M. The nuclear localization signal is required for nuclear GPER translocation and function in breast Cancer-Associated Fibroblasts (CAFs). Mol Cell Endocrinol 2013; 376:23-32. [PMID: 23748028 DOI: 10.1016/j.mce.2013.05.023] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/09/2013] [Revised: 04/02/2013] [Accepted: 05/30/2013] [Indexed: 12/26/2022]
Abstract
Cancer associated fibroblasts (CAFs) actively contribute to the growth and invasion of cancer cells. In recent years, the G protein estrogen receptor (GPER) has been largely involved in the estrogenic signals in diverse types of normal and tumor cells. In CAFs, GPER was localized into the nucleus, however the molecular mechanisms which regulate its nuclear shuttle remain to be clarified. In the present study, we demonstrate that in breast CAFs GPER translocates into the nucleus through an importin-dependent mechanism. Moreover, we show that a nuclear localization signal is involved in the nuclear import of GPER, in the up-regulation of its target genes c-fos and CTGF and in the migration of CAFs induced by estrogens. Our data provide novel insights into the nuclear localization and function of GPER in CAFs toward a better understanding of the estrogen action elicited through these key players of the tumor microenvironment.
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Affiliation(s)
- Marco Pupo
- Department of Pharmacy, Health and Nutritional Sciences, University of Calabria, Rende, Italy
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Prossnitz ER, Arterburn JB, Edwards BS, Sklar LA, Oprea TI. Steroid-binding G-protein-coupled receptors: new drug discovery targets for old ligands. Expert Opin Drug Discov 2013; 1:137-50. [PMID: 23495797 DOI: 10.1517/17460441.1.2.137] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Steroid-binding receptors have long been a successful target class for the pharmaceutical industry. Clinical applications for steroids range from contraception and hormone replacement therapy to immune regulation and cancer therapy. With the recent demonstration that the orphan GPCR, GPR30 binds and is activated by estrogen, as well as the identification of a GPR30-selective agonist, it is likely that GPR30 represents a novel drug target with many potential clinical applications. This review discusses the role of GPR30 in mediating the effects of estrogen, as well as recent efforts to isolate GPR30-specific ligands using a combination of virtual and biomolecular screening. Finally, comments are made on the future directions regarding GPCRs, steroids and drug discovery.
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Affiliation(s)
- Eric R Prossnitz
- Department of Cell Biology & Physiology, MSC08-4750 University of New Mexico, Albuquerque, NM 87131, USA.
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Tucker SC, Honn KV. Emerging targets in lipid-based therapy. Biochem Pharmacol 2013; 85:673-688. [PMID: 23261527 PMCID: PMC4106802 DOI: 10.1016/j.bcp.2012.11.028] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2012] [Revised: 11/29/2012] [Accepted: 11/30/2012] [Indexed: 02/07/2023]
Abstract
The use of prostaglandins and NSAIDS in the clinic has proven that lipid mediators and their associated pathways make attractive therapeutic targets. When contemplating therapies involving lipid pathways, several basic agents come to mind. There are the enzymes and accessory proteins that lead to the metabolism of lipid substrates, provided through diet or through actions of lipases, the subsequent lipid products, and finally the lipid sensors or receptors. There is abundant evidence that molecules along this lipid continuum can serve as prognostic and diagnostic indicators and are in fact viable therapeutic targets. Furthermore, lipids themselves can be used as therapeutics. Despite this, the vernacular dialog pertaining to "biomarkers" does not routinely include mention of lipids, though this is rapidly changing. Collectively these agents are becoming more appreciated for their respective roles in diverse disease processes from cancer to preterm labor and are receiving their due appreciation after decades of ground work in the lipid field. By relating examples of disease processes that result from dysfunction along the lipid continuum, as well as examples of lipid therapies and emerging technologies, this review is meant to inspire further reading and discovery.
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Affiliation(s)
- Stephanie C Tucker
- Department of Pathology, Wayne State University School of Medicine, and Karmanos Cancer Institute, Detroit, MI 48202, USA.
| | - Kenneth V Honn
- Department of Pathology, Wayne State University School of Medicine, and Karmanos Cancer Institute, Detroit, MI 48202, USA; Department of Chemistry, Wayne State University School of Medicine, and Karmanos Cancer Institute, Detroit, MI 48202, USA.
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Bäck M, Dahlén SE, Drazen JM, Evans JF, Serhan CN, Shimizu T, Yokomizo T, Rovati GE. International Union of Basic and Clinical Pharmacology. LXXXIV: Leukotriene Receptor Nomenclature, Distribution, and Pathophysiological Functions. Pharmacol Rev 2011; 63:539-84. [DOI: 10.1124/pr.110.004184] [Citation(s) in RCA: 117] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
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Affiliation(s)
- Motonao Nakamura
- Department of Biochemistry and Molecular Biology, Faculty of Medicine, The University of Tokyo, Hongo, Tokyo, Japan.
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Penna C, Bassino E, Alloatti G. Platelet activating factor: the good and the bad in the ischemic/reperfused heart. Exp Biol Med (Maywood) 2011; 236:390-401. [PMID: 21378031 DOI: 10.1258/ebm.2011.010316] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
The present review is focused on the dual role played by platelet-activating factor (PAF) in ischemia and reperfusion (I/R) injury of the heart. Although the involvement of PAF in the pathogenesis of myocardial reperfusion injury is well established, in the last few years it has emerged that very low concentrations of PAF exert cardioprotective effects, comparable to that afforded by ischemic preconditioning (IP). PAF is a potent phosphoglyceride involved in different pathophysiological conditions affecting the cardiovascular system, including the development of myocardial I/R injury. PAF is released from the I/R myocardium in concentrations (1-10 nmol/L) high enough to negatively modulate coronary circulation as well as electrical and contractile activities. PAF may act either directly, via generation of secondary mediators, or through the activation of inflammatory cells like platelets and polymorphonuclear neutrophils, which exacerbate postischemic myocardial injury. The effects of PAF are mediated through specific receptors (PAFRs) that belong to the superfamily of G protein-coupled receptors. Since cardiomyocytes not only produce PAF but also possess PAFRs, it is likely that PAF acts as an autocrine/paracrine mediator. Although the negative effects exerted by high concentrations of PAF are well established, several recent findings from our and other laboratories have demonstrated that very low concentrations (pmol/L) of PAF infused before ischemia induce cardioprotective effects similar to those afforded by IP, and that endogenous PAF production participates in the induction of IP itself. The IP-like action exerted by low concentrations of PAF is due to the activation/phosphorylation of kinases included in the reperfusion injury salvage kinase (RISK) pathway, such as protein kinase C, Akt/PkB and nitric oxide synthase. Together with the activation of mitochondrial K(ATP) channels, these events may allow prevention of mitochondrial permeability transition pores opening at reperfusion. Moreover, the nitric oxide-dependent S-nitrosylation of L-type Ca(2+) channels induced by PAF reduces intracellular Ca(2+) overload.
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Affiliation(s)
- Claudia Penna
- Dipartimento di Scienze Cliniche e Biologiche, ASO San Luigi, 10043 Orbassano (TO), Italy
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Liu J, Chen R, Marathe GK, Febbraio M, Zou W, McIntyre TM. Circulating platelet-activating factor is primarily cleared by transport, not intravascular hydrolysis by lipoprotein-associated phospholipase A2/ PAF acetylhydrolase. Circ Res 2010; 108:469-77. [PMID: 21183738 DOI: 10.1161/circresaha.110.228742] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
RATIONALE The phospholipid platelet-activating factor (PAF) stimulates all cells of the innate immune system and numerous cardiovascular cells. A single enzyme (plasma PAF acetylhydrolase [PAF-AH] or lipoprotein-associated phospholipase [Lp-PL]A(2)) in plasma hydrolyzes PAF, but significant controversy exists whether its action is pro- or antiinflammatory and accordingly whether its inhibition will slow cardiovascular disease. OBJECTIVE We sought to define how PAF and related short-chain oxidized phospholipids turnover in vivo and the role of PAF acetylhydrolase/Lp-PLA(2) in this process. METHODS AND RESULTS [(3)H-acetyl]PAF was hydrolyzed by murine or human plasma (t(1/2), 3 and 7 minutes, respectively), but injected [(3)H-acetyl]PAF disappeared from murine circulation more quickly (t(1/2), <30 seconds). [(3)H]PAF clearance was unchanged in PAF receptor(-/-) animals, or over the first 2 half-lives in PAF-AH(-/-) animals. [(3)H]PAF turnover was reduced by coinjecting excess unlabeled PAF or an oxidatively truncated phospholipid, and [(3)H]PAF clearance was slowed in hyperlipidemic apolipoprotein (apo)E(-/-) mice with excess circulating oxidatively truncated phospholipids. [(3)H]PAF, fluorescent NBD-PAF, or fluorescent oxidatively truncated phospholipid were primarily accumulated by liver and lung, and were transported into endothelium as intact phospholipids through a common mechanism involving TMEM30a. CONCLUSIONS Circulating PAF and oxidized phospholipids are continually and rapidly cleared, and hence continually and rapidly produced. Saturable PAF receptor-independent transport, rather than just intravascular hydrolysis, controls circulating inflammatory and proapoptotic oxidized phospholipid mediators. Intravascular PAF has access to intracellular compartments. Inflammatory and proapoptotic phospholipids may accumulate in the circulation as transport is overwhelmed by substrates in hyperlipidemia.
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Affiliation(s)
- Jinbo Liu
- Department of Cell Biology, NE10, Lerner Research Institute, Cleveland Clinic Lerner College of Medicine, Cleveland, OH 44195, USA
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Arterburn JB, Oprea TI, Prossnitz ER, Edwards BS, Sklar LA. Discovery of selective probes and antagonists for G-protein-coupled receptors FPR/FPRL1 and GPR30. Curr Top Med Chem 2010; 9:1227-36. [PMID: 19807662 DOI: 10.2174/156802609789753608] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2009] [Accepted: 07/29/2009] [Indexed: 01/04/2023]
Abstract
Recent technological advances in flow cytometry provide a versatile platform for high throughput screening of compound libraries coupled with high-content biological testing and drug discovery. The G protein-coupled receptors (GPCRs) constitute the largest class of signaling molecules in the human genome with frequent roles in disease pathogenesis, yet many examples of orphan receptors with unknown ligands remain. The complex biology and potential for drug discovery within this class provide strong incentives for chemical biology approaches seeking to develop small molecule probes to facilitate elucidation of mechanistic pathways and enable specific manipulation of the activity of individual receptors. We have initiated small molecule probe development projects targeting two distinct families of GPCRs: the formylpeptide receptors (FPR/FPRL1) and G protein-coupled estrogen receptor (GPR30). In each case the assay for compound screening involved the development of an appropriate small molecule fluorescent probe, and the flow cytometry platform provided inherently biological rich assays that enhanced the process of identification and optimization of novel antagonists. The contributions of cheminformatics analysis tools, virtual screening, and synthetic chemistry in synergy with the biomolecular screening program have yielded valuable new chemical probes with high binding affinity, selectivity for the targeted receptor, and potent antagonist activity. This review describes the discovery of novel small molecule antagonists of FPR and FPRL1, and GPR30, and the associated characterization process involving secondary assays, cell based and in vivo studies to define the selectivity and activity of the resulting chemical probes.
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Affiliation(s)
- Jeffrey B Arterburn
- Department of Chemistry and Biochemistry, New Mexico State University, Las Cruces, NM 88003, USA.
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Komarova Y, Malik AB. Regulation of endothelial permeability via paracellular and transcellular transport pathways. Annu Rev Physiol 2010; 72:463-93. [PMID: 20148685 DOI: 10.1146/annurev-physiol-021909-135833] [Citation(s) in RCA: 468] [Impact Index Per Article: 33.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The endothelium functions as a semipermeable barrier regulating tissue fluid homeostasis and transmigration of leukocytes and providing essential nutrients across the vessel wall. Transport of plasma proteins and solutes across the endothelium involves two different routes: one transcellular, via caveolae-mediated vesicular transport, and the other paracellular, through interendothelial junctions. The permeability of the endothelial barrier is an exquisitely regulated process in the resting state and in response to extracellular stimuli and mediators. The focus of this review is to provide a comprehensive overview of molecular and signaling mechanisms regulating endothelial barrier permeability with emphasis on the cross-talk between paracellular and transcellular transport pathways.
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Affiliation(s)
- Yulia Komarova
- Department of Pharmacology and Center for Lung and Vascular Biology, University of Illinois College of Medicine, Chicago, IL 60612, USA
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15
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He YG, Wang H, Zhao B, Hsu M, Liao D, Owens J, Johnston J. Functional analysis of platelet-activating factor in the retinal pigment epithelial cells and choroidal endothelial cells. Curr Eye Res 2010; 34:957-65. [PMID: 19958112 DOI: 10.3109/02713680903231135] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
PURPOSE To investigate the function of platelet-activating factor (PAF) in cultured retinal pigment epithelial (RPE) and choroidal endothelial (CE) cells. METHODS The in vitro and in vivo expression of PAF-receptors (PAF-R) on both these cells was determined. The production of PAF by RPE cells was also determined. The effect of PAF on the proliferation, migration, permeability, and apoptosis of CE cells was examined, and the modulation of PAF on the VEGF level in RPE cells was assessed. RESULTS PAF-R was present in both types of cells in vitro, as well as in RPE and choroid in vivo. Cultured RPE cells synthesized PAF. PAF stimulated CE cell migration and permeability but not the proliferation. PAF also increased the VEGF level in RPE cells. CONCLUSIONS Similar to VEGF, PAF stimulates CE cell migration and permeability. It also up-regulates VEGF level in RPE cells. PAF may be involved in the pathogenesis of choroidal neovascularization.
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Affiliation(s)
- Yu-Guang He
- Department of Ophthalmology, UT Southwestern Medical Center at Dallas, Dallas, Texas 75390-9057, USA.
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Lee M, Choi S, Halldén G, Yo SJ, Schichnes D, Aponte GW. P2Y5 is a G(alpha)i, G(alpha)12/13 G protein-coupled receptor activated by lysophosphatidic acid that reduces intestinal cell adhesion. Am J Physiol Gastrointest Liver Physiol 2009; 297:G641-54. [PMID: 19679818 PMCID: PMC2763810 DOI: 10.1152/ajpgi.00191.2009] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
P2Y5 is a G protein-coupled receptor that binds and is activated by lysophosphatidic acid (LPA). We determined that P2Y5 transcript is expressed along the intestinal mucosa and investigated the intracellular pathways induced by P2Y5 activation, which could contribute to LPA effects on intestinal cell adhesion. P2Y5 heterologously expressed in CHO and small intestinal hBRIE 380i cells was activated by LPA resulting in an increase in intracellular calcium ([Ca(2+)](i)) when the cells concurrently expressed G(alpha)(Delta6qi5myr). P2Y5 activation also increased the phosphorylation of ERK1/2 that was sensitive to pertussis toxin. Together these indicate that P2Y5 activation by LPA induces an increase in [Ca(2+)](i) and ERK1/2 phosphorylation through G(alpha)(i). We discovered that P2Y5 was activated by farnesyl pyrophosphate (FPP) without a detectable change in [Ca(2+)](i). The activation of P2Y5 by LPA or FPP induced the activity of a serum response element (SRE)-linked luciferase reporter that was inhibited by the RGS domain of p115RhoGEF, C3 exotoxin, and Y-27632, suggesting the involvement of G(alpha)(12/13), Rho GTPase, and ROCK, respectively. However, only LPA-mediated induction of SRE reporter activity was sensitive to inhibitors targeting p38 MAPK, PI3K, PLC, and PKC. In addition, only LPA transactivated the epidermal growth factor receptor, leading to an induction of ERK1/2 phosphorylation. These observations correlate with our subsequent finding that P2Y5 activation by LPA, and not FPP, reduced intestinal cell adhesion. This study elucidates a mechanism whereby LPA can act as a luminal and/or serosal cue to alter mucosal integrity.
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Affiliation(s)
- Mike Lee
- 1Department of Nutritional Science and Toxicology, University of California at Berkeley, Berkeley, California; and
| | - Sungwon Choi
- 1Department of Nutritional Science and Toxicology, University of California at Berkeley, Berkeley, California; and
| | - Gunnel Halldén
- 1Department of Nutritional Science and Toxicology, University of California at Berkeley, Berkeley, California; and
| | - Sek Jin Yo
- 1Department of Nutritional Science and Toxicology, University of California at Berkeley, Berkeley, California; and
| | - Denise Schichnes
- 2College of Natural Resources Biological Imaging Facility, University of California at Berkeley, Berkeley, California
| | - Gregory W. Aponte
- 1Department of Nutritional Science and Toxicology, University of California at Berkeley, Berkeley, California; and
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17
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Favre N, Camps M, Arod C, Chabert C, Rommel C, Pasquali C. Chemokine receptor CCR2 undergoes transportin1-dependent nuclear translocation. Proteomics 2008; 8:4560-76. [PMID: 18846510 DOI: 10.1002/pmic.200800211] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Chemokines (CCs) are small chemoattractant cytokines involved in a wide variety of biological and pathological processes. Released by cells in the milieu, and extracellular matrix and activating signalling cascades upon binding to specific G protein-coupled receptors (GPCRs), they trigger many cellular events. In various pathologies, CCs are directly responsible for excessive recruitment of leukocytes to inflammatory sites and recent studies using chemokine receptor (CCR) antagonists permitted these molecules to reach the market for medical use. While interaction of CCs with their receptors has been extensively documented, downstream GPCR signalling cascades triggered by CC are less well understood. Given the pivotal role of chemokine receptor 2 (CCR2) in monocyte recruitment, activation and differentiation and its implication in several autoimmune-inflammatory pathologies, we searched for potential new CCR2-interacting proteins by engineering a modified CCR2 that we used as bait. Herein, we show the direct interaction of CCR2 with transportin1 (TRN1), which we demonstrate is followed by CCR2 receptor internalization. Further characterization of this novel interaction revealed that TRN1-binding to CCR2 increased upon time in agonist treated cells and promotes its nuclear translocation in a TRN1-dependent manner. Finally, we provide evidence that following translocation, the receptor localizes at the outer edge of the nuclear envelope where it is finally released from TRN1.
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18
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Estrada R, Wang L, Jala VR, Lee JF, Lin CY, Gray RD, Haribabu B, Lee MJ. Ligand-induced nuclear translocation of S1P(1) receptors mediates Cyr61 and CTGF transcription in endothelial cells. Histochem Cell Biol 2008; 131:239-49. [PMID: 18936953 DOI: 10.1007/s00418-008-0521-9] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/24/2008] [Indexed: 01/26/2023]
Abstract
Sphingosine-1-phosphate (S1P) receptor subtype 1 (S1P(1)), a G-protein coupled receptor (GPCR), regulates many biological activities of endothelial cells (ECs). In this report, we show that S1P(1) receptors are present in the nuclei of ECs by using various biochemical and microscopic techniques such as cellular fractionation, immunogold labeling, and confocal microscopic analysis. Live cell imaging showed that plasma membrane S1P(1) receptors are rapidly internalized and subsequently translocated to nuclear compartment upon S1P stimulation. Utilizing membrane biotinylation technique further supports the notion that nuclear S1P(1) receptors were internalized from plasma membrane S1P(1) after ligand treatment. Moreover, nuclear S1P(1) is able to regulate the transcription of Cyr61 and CTGF, two growth factors functionally important in the regulation of vasculature. Collectively, these data suggest a novel S1P-S1P(1) signaling axis present in the nuclear compartment of endothelial cells, which may regulate biological responses of endothelium.
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Affiliation(s)
- Rosendo Estrada
- Department of Microbiology and Immunology, Gheens Center on Aging, University of Louisville Health Sciences Center, Louisville, KY 40202, USA
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19
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Nuclear localisation of the endocannabinoid metabolizing enzyme fatty acid amide hydrolase (FAAH) in invasive trophoblasts and an association with recurrent miscarriage. Placenta 2008; 29:970-5. [PMID: 18805581 DOI: 10.1016/j.placenta.2008.08.003] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/24/2008] [Revised: 08/06/2008] [Accepted: 08/06/2008] [Indexed: 11/22/2022]
Abstract
Endocannabinoids are lipid signalling molecules that are related to the major psychoactive component in marijuana, delta-9-tetrahydrocannabinol and are increasingly recognized as being important in implantation and development of early embryos. The endocannabinoid anandamide, is metabolized by the enzyme fatty acid amide hydrolase (FAAH), and insufficient levels of this enzyme have been implicated in spontaneous miscarriage in women and implantation failure in mice. We screened placental bed biopsies and placental tissue from 45 women with recurrent miscarriage and 17 gestation-matched women with normal pregnancies for the expression of FAAH by immunohistochemistry. Unexpectedly, the enzyme appeared to be localised to the nucleus of trophoblasts and this was confirmed by western blotting of sub-cellular fractions and confocal microscopy. FAAH was expressed in the cytoplasm of large decidual stromal cells and significantly more women with recurrent miscarriage (73%) expressed FAAH in these cells than women with normal pregnancy (31%). FAAH was also expressed in the nucleus of extravillous trophoblasts that had invaded the decidua from 67% of women with recurrent miscarriage but was not expressed by these cells in any women with normal pregnancies. In contrast, FAAH was expressed in extravillous trophoblasts that had migrated out of the villi but that had not yet invaded the decidua in both normal pregnancies and in cases of recurrent miscarriage. FAAH was also present in the nucleus of a small number of villous trophoblasts in some specimens. FAAH appears to be over expressed in trophoblasts that have invaded the decidua, as well as in large decidual stromal cells in many cases of recurrent miscarriage. This may reflect inadequate control of the cannabinoid system in the uterus of women who experience recurrent miscarriages. The functional significance of the unexpected nuclear localisation of FAAH in trophoblasts is not yet clear.
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20
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Hooks SB, Cummings BS. Role of Ca2+-independent phospholipase A2 in cell growth and signaling. Biochem Pharmacol 2008; 76:1059-67. [PMID: 18775417 DOI: 10.1016/j.bcp.2008.07.044] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2008] [Revised: 07/15/2008] [Accepted: 07/15/2008] [Indexed: 01/25/2023]
Abstract
Phospholipase A(2) (PLA(2)) are esterases that cleave glycerophospholipids to release fatty acids and lysophospholipids. Several studies demonstrate that PLA(2) regulate growth and signaling in several cell types. However, few of these studies have focused on Ca2+-independent phospholipase A(2) (iPLA(2) or Group VI PLA(2)). This class of PLA(2) was originally suggested to mediate phospholipid remodeling in several cell types including macrophages. As such, it was labeled as a housekeeping protein and thought not to play as significant of roles in cell growth as its older counterparts cytosolic PLA(2) (cPLA(2) or Group IV PLA(2)) and secretory PLA(2) (sPLA(2) or Groups I-III, V and IX-XIV PLA(2)). However, several recent studies demonstrate that iPLA(2) mediate cell growth, and do so by participating in signal transduction pathways that include epidermal growth factor receptors (EGFR), mitogen activated protein kinases (MAPK), mdm2, and even the tumor suppressor protein p53 and the cell cycle regulator p21. The exact mechanism by which iPLA(2) mediates these pathways are not known, but likely involve the generation of lipid signals such as arachidonic acid, lysophosphatidic acid (LPA) and lysophosphocholines (LPC). This review discusses the role of iPLA(2) in cell growth with special emphasis placed on their role in cell signaling. The putative lipid signals involved are also discussed.
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Affiliation(s)
- Shelley B Hooks
- Department of Pharmaceutical and Biomedical Sciences, College of Pharmacy, University of Georgia, Athens, GA 30602, USA
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21
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Albanito L, Sisci D, Aquila S, Brunelli E, Vivacqua A, Madeo A, Lappano R, Pandey DP, Picard D, Mauro L, Andò S, Maggiolini M. Epidermal growth factor induces G protein-coupled receptor 30 expression in estrogen receptor-negative breast cancer cells. Endocrinology 2008; 149:3799-808. [PMID: 18467441 PMCID: PMC2488235 DOI: 10.1210/en.2008-0117] [Citation(s) in RCA: 107] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Different cellular receptors mediate the biological effects induced by estrogens. In addition to the classical nuclear estrogen receptors (ERs)-alpha and -beta, estrogen also signals through the seven-transmembrane G-protein-coupled receptor (GPR)-30. Using as a model system SkBr3 and BT20 breast cancer cells lacking the classical ER, the regulation of GPR30 expression by 17beta-estradiol, the selective GPR30 ligand G-1, IGF-I, and epidermal growth factor (EGF) was evaluated. Transient transfections with an expression plasmid encoding a short 5'-flanking sequence of the GPR30 gene revealed that an activator protein-1 site located within this region is required for the activating potential exhibited only by EGF. Accordingly, EGF up-regulated GPR30 protein levels, which accumulated predominantly in the intracellular compartment. The stimulatory role elicited by EGF on GPR30 expression was triggered through rapid ERK phosphorylation and c-fos induction, which was strongly recruited to the activator protein-1 site found in the short 5'-flanking sequence of the GPR30 gene. Of note, EGF activating the EGF receptor-MAPK transduction pathway stimulated a regulatory loop that subsequently engaged estrogen through GPR30 to boost the proliferation of SkBr3 and BT20 breast tumor cells. The up-regulation of GPR30 by ligand-activated EGF receptor-MAPK signaling provides new insight into the well-known estrogen and EGF cross talk, which, as largely reported, contributes to breast cancer progression. On the basis of our results, the action of EGF may include the up-regulation of GPR30 in facilitating a stimulatory role of estrogen, even in ER-negative breast tumor cells.
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Affiliation(s)
- Lidia Albanito
- Department Pharmaco-Biology, University of Calabria, 87030 Rende (Cosenze), Italy
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22
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Rozenfeld R, Devi LA. Regulation of CB1 cannabinoid receptor trafficking by the adaptor protein AP-3. FASEB J 2008; 22:2311-22. [PMID: 18267983 DOI: 10.1096/fj.07-102731] [Citation(s) in RCA: 122] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Cannabinoid receptor 1 (CB(1)) is an abundant G protein-coupled receptor, involved in a number of physiological processes. This receptor is localized at the plasma membrane, as well as in intracellular vesicles. The trafficking events leading to this intracellular localization remain controversial. In this study, we examine the differential trafficking of CB(1) receptors and its implication on signaling. We find that the transfected tagged receptors are predominantly at the plasma membrane, whereas endogenous receptors exhibit an intracellular localization. We also find that intracellular endogenous CB(1) receptors do not have an endocytic origin. Instead, these receptors associate with the adaptor protein AP-3 and traffic to the lysosomes. siRNA-mediated AP-3delta knockdown leads to enhanced cell surface localization of CB(1) receptors. Finally, we show that CB(1) receptors in the late endosomal/lysosomal compartment are associated with heterotrimeric G proteins and mediate signal transduction. These results suggest that intracellular CB(1) receptors are functional and that their spatial segregation is likely to significantly affect receptor function.
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Affiliation(s)
- Raphael Rozenfeld
- Department of Pharmacology and Systems Therapeutics, Mount Sinai School of Medicine, One Gustave L. Levy Place, New York, NY 10029, USA
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23
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Gater DL, Seddon JM, Law RV. Formation of the liquid-ordered phase in fully hydrated mixtures of and. SOFT MATTER 2008; 4:263-267. [PMID: 32907239 DOI: 10.1039/b710726a] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The role of cholesterol (Chol) in promoting lamellar phase formation in mixtures with 1-palmitoyl-2-hydroxy-sn-glycero-3-phosphocholine (Lyso-PPC) in excess water was investigated using multinuclear solid-state NMR and X-ray scattering. It was found that mixtures containing Chol and Lyso-PPC form a liquid-ordered (Lo) lamellar phase over a range of temperatures and concentrations, as previously observed in mixtures of Chol with various diacylphospholipids. The maximum quadrupolar splitting of the 2H-NMR powder patterns for samples containing per-deuterated Lyso-PPC were 40-50 kHz which is strongly indicative of an Lo phase. This evidence was supported by wide angle X-ray scattering data which showed a characteristic diffuse peak centred at 4.2 Å. The Lo phase coexists with an isotropic Lyso-PPC phase at Chol concentrations up to 70 mol% Chol, and with Chol crystals at Chol concentrations above this value. Below 70 mol% Chol, an increase in the concentration of Chol in the system caused a corresponding increase in the proportion of the Lo phase present compared with the amount of isotropic Lyso-PPC. The chemical-shift anisotropy (CSA) of the static 31P-NMR spectra of the Lo phase showed the symmetry of a lamellar phase, but the linewidth, Δσ, was much narrower than CSA powder patterns obtained for diacylphospholipids in similar conditions, being ∼20 ppm as opposed to ∼40 ppm, respectively.
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Affiliation(s)
- Deborah L Gater
- Department of Chemistry, Imperial College, South Kensington Campus, London, UKSW7 2AZ.
| | - John M Seddon
- Department of Chemistry, Imperial College, South Kensington Campus, London, UKSW7 2AZ.
| | - Robert V Law
- Department of Chemistry, Imperial College, South Kensington Campus, London, UKSW7 2AZ.
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24
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Avendaño-Vázquez SE, Cabrera-Wrooman A, Colín-Santana CC, García-Sáinz JA. Lysophosphatidic acid LPA1 receptor close-up. ACTA ACUST UNITED AC 2007. [DOI: 10.1002/sita.200700138] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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25
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Lyssand JS, Bajjalieh SM. The heterotrimeric [corrected] G protein subunit G alpha i is present on mitochondria. FEBS Lett 2007; 581:5765-8. [PMID: 18037379 DOI: 10.1016/j.febslet.2007.11.044] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2007] [Revised: 11/07/2007] [Accepted: 11/12/2007] [Indexed: 01/20/2023]
Abstract
Receptors that signal through heterotrimeric [corrected] GTP binding (G) proteins mediate the majority of intercellular communication. Recent evidence suggests that receptors acting through G proteins also transfer signals across the nuclear membrane. Here we present cell fractionation and immunolabeling data showing that the heterotrimeric [corrected] G protein subunit Galphai is associated with mitochondria. This finding suggests that G protein receptor signaling may be a feature common to all membranes.
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Affiliation(s)
- John S Lyssand
- Department of Pharmacology, University of Washington Seattle, Box 357750, WA, USA
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26
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Capra V, Thompson MD, Sala A, Cole DE, Folco G, Rovati GE. Cysteinyl-leukotrienes and their receptors in asthma and other inflammatory diseases: critical update and emerging trends. Med Res Rev 2007; 27:469-527. [PMID: 16894531 DOI: 10.1002/med.20071] [Citation(s) in RCA: 133] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Cysteinyl-leukotrienes (cysteinyl-LTs), that is, LTC4, LTD4, and LTE4, trigger contractile and inflammatory responses through the specific interaction with G protein-coupled receptors (GPCRs) belonging to the purine receptor cluster of the rhodopsin family, and identified as CysLT receptors (CysLTRs). Cysteinyl-LTs have a clear role in pathophysiological conditions such as asthma and allergic rhinitis (AR), and have been implicated in other inflammatory conditions including cardiovascular diseases, cancer, atopic dermatitis, and urticaria. Molecular cloning of human CysLT1R and CysLT2R subtypes has confirmed most of the previous pharmacological characterization and identified distinct expression patterns only partially overlapping. Interestingly, recent data provide evidence for the immunomodulation of CysLTR expression, the existence of additional receptor subtypes, and of an intracellular pool of CysLTRs that may have roles different from those of plasma membrane receptors. Furthermore, genetic variants have been identified for the CysLTRs that may interact to confer risk for atopy. Finally, a crosstalk between the cysteinyl-LT and the purine systems is being delineated. This review will summarize and attempt to integrate recent data derived from studies on the molecular pharmacology and pharmacogenetics of CysLTRs, and will consider the therapeutic opportunities arising from the new roles suggested for cysteinyl-LTs and their receptors.
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MESH Headings
- Adult
- Animals
- Asthma/drug therapy
- Asthma/physiopathology
- Cardiovascular Diseases/physiopathology
- Child
- Child, Preschool
- Dermatitis, Atopic/drug therapy
- Dermatitis, Atopic/etiology
- Female
- Humans
- Hydroxyurea/adverse effects
- Hydroxyurea/analogs & derivatives
- Leukotriene Antagonists/adverse effects
- Leukotriene Antagonists/therapeutic use
- Leukotriene C4/physiology
- Leukotriene D4/physiology
- Leukotriene E4/physiology
- Membrane Proteins/drug effects
- Membrane Proteins/genetics
- Membrane Proteins/physiology
- Pharmacogenetics
- Receptors, Leukotriene/drug effects
- Receptors, Leukotriene/genetics
- Receptors, Leukotriene/physiology
- Receptors, Purinergic/physiology
- Recombinant Proteins/pharmacology
- Rhinitis, Allergic, Seasonal/drug therapy
- Rhinitis, Allergic, Seasonal/physiopathology
- SRS-A/biosynthesis
- Tissue Distribution
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Affiliation(s)
- Valérie Capra
- Department of Pharmacological Sciences, University of Milan, Via Balzaretti 9, 20133 Milan, Italy.
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27
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Revankar CM, Mitchell HD, Field AS, Burai R, Corona C, Ramesh C, Sklar LA, Arterburn JB, Prossnitz ER. Synthetic estrogen derivatives demonstrate the functionality of intracellular GPR30. ACS Chem Biol 2007; 2:536-44. [PMID: 17655271 DOI: 10.1021/cb700072n] [Citation(s) in RCA: 124] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Estrogen mediates its effects through multiple cellular receptors. In addition to the classical nuclear estrogen receptors (ERalpha and ERbeta), estrogen also signals through the seven-transmembrane G-protein-coupled receptor (GPCR) GPR30. Although estrogen is a cell-permeable ligand, it is often assumed that all GPCRs function solely as cell surface receptors. Our previous results showed that GPR30 appeared to be expressed predominantly in the endoplasmic reticulum. A critical question that arises is whether this localization represents the site of functional receptor. To address this question, we synthesized a collection of cell-permeable and cell-impermeable estrogen derivatives. We hypothesized that if functional GPR30 were expressed at the cell surface, both permeable and impermeable derivatives would show activity. However, if functional GPR30 were predominantly intracellular, like ERalpha, only the permeable ligands should show activity. Cell permeability was assessed using cells expressing ERalpha as a model intracellular estrogen-binding receptor. Our results reveal that despite exhibiting similar binding affinities for GPR30, only the cell-permeable ligands are capable of stimulating rapid calcium mobilization and phosphoinositide 3-kinase (PI3K) activation. We conclude that GPR30 expressed intracellularly is capable of initiating cellular signaling and that there is insufficient GPR30 expressed on the cell surface to initiate signaling in response to impermeable ligands in the cell lines examined. To our knowledge, this is the first definitive demonstration of a functional intracellular transmembrane estrogen receptor.
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Affiliation(s)
- Chetana M Revankar
- Cancer Research and Treatment Center, University of New Mexico Health Sciences Center, Albuquerque, New Mexico 87131, USA
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28
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Ferreira MAND, Barcelos LS, Teixeira MM, Bakhle YS, Andrade SP. Tumor growth, angiogenesis and inflammation in mice lacking receptors for platelet activating factor (PAF). Life Sci 2007; 81:210-7. [PMID: 17588613 DOI: 10.1016/j.lfs.2007.05.003] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2007] [Revised: 04/24/2007] [Accepted: 05/02/2007] [Indexed: 11/28/2022]
Abstract
Tumor growth is associated with angiogenesis and inflammation and the endogenous lipid, platelet activating factor (PAF), is a pro-inflammatory and pro-angiogenic mediator. We therefore measured tumor growth, angiogenesis and inflammation in normal (WT) mice and those lacking the receptor for PAF, through gene deletion (PAFR-KO). Growth of solid tumors derived from colon 26 cells was not altered but that from Ehrlich cells was markedly (5-fold) increased in the PAFR-KO mice, relative to the WT strain. Angiogenesis, as tumor content of VEGF or hemoglobin, was increased in both tumors from the mutant strain. Inflammation, as neutrophil and macrophage accumulation and chemokine (CXCL2 and CCL2) content of tumors, was decreased or unchanged in the tumors implying an overall decrease in the inflammatory response in the PAFR-KO strain. We also assessed growth of the Ehrlich tumor in its ascites form, after i.p. injection. Here growth (ascites volume) was inhibited by about 30%, but neutrophil and macrophage numbers were increased in the ascites fluid from the PAFR-KO mice. Angiogenesis in the peritoneal wall, which is not invaded by the tumor cells, was increased but leukocyte infiltration decreased in the mutant strain. Our results show, unexpectedly, that tumor-induced angiogenesis was increased in mice lacking response to PAF, from which we infer that in normal (WT) mice, PAF is anti-angiogenic. Further, although growth was still associated with angiogenesis in PAFR-KO mice, growth was not correlated with inflammation (leukocyte accumulation).
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Affiliation(s)
- M A N D Ferreira
- Department of Physiology , General Pathology, Institute of Biological Sciences, Federal University of Minas Gerais, Av. Antonio Carlos 6627, Cx Post 468, Campus Pampulha, CEP 31270-901, Belo Horizonte/MG, Brazil
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29
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Ramamurthy S, Mir F, Gould RM, Le Breton GC. Characterization of thromboxane A2 receptor signaling in developing rat oligodendrocytes: nuclear receptor localization and stimulation of myelin basic protein expression. J Neurosci Res 2007; 84:1402-14. [PMID: 16998891 DOI: 10.1002/jnr.21061] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
The present work investigates the role of thromboxane A(2) (TXA(2)) receptors in the development of oligodendrocytes (OLGs). The results demonstrate that the proteins of the TXA(2) signaling pathway, i.e., cyclooxygenase (COX-1), TXA(2) synthase (TS), and TXA(2) receptor (TPR) are expressed in the developing rat brain during myelination. Furthermore, culture of OLG progenitor cells (OPCs) revealed that the expression levels of these proteins as well as TXA(2) synthesis increase during OLG maturation. Separate studies established that activation of TPRs by the agonist U46619 increases intracellular calcium in both OPCs and OLGs as visualized by digital fluorescence imaging. Immunocytochemical staining demonstrated that TPRs are localized in the plasma membrane and perinuclear compartments in OPCs. However, during OLG differentiation, TPRs shift their localization pattern and also become associated with the nuclear compartment. This shift to nuclear localization was confirmed by biochemical analysis in cultured cells and by immunocytochemical analysis in developing rat brain. Finally, it was found that U46619 activation of TPRs in maturing OLGs resulted in enhanced myelin basic protein (MBP) expression. Alternatively, inhibition of endogenous TPR signaling led to reduced MBP expression. Furthermore, TPR-mediated MBP expression was found to be associated with increased transcription from the MBP promoter using a MBP-luciferase reporter. Collectively, these findings suggest a novel TPR signaling pathway in OLGs and a potential role for this signaling during OLG maturation and myelin production.
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MESH Headings
- 15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid/pharmacology
- Age Factors
- Animals
- Animals, Newborn
- Blotting, Western/methods
- Brain/cytology
- Calcium/metabolism
- Cell Differentiation/drug effects
- Cell Differentiation/physiology
- Cells, Cultured
- Cyclic AMP/metabolism
- Enzyme Inhibitors/pharmacology
- Gangliosides/metabolism
- Gene Expression Regulation, Developmental/drug effects
- Gene Expression Regulation, Developmental/physiology
- Myelin Basic Protein/metabolism
- Oligodendroglia/drug effects
- Oligodendroglia/metabolism
- Rats
- Rats, Sprague-Dawley
- Receptors, Cytoplasmic and Nuclear/drug effects
- Receptors, Cytoplasmic and Nuclear/metabolism
- Receptors, Thromboxane A2, Prostaglandin H2/physiology
- Signal Transduction/drug effects
- Signal Transduction/physiology
- Stem Cells/drug effects
- Stem Cells/physiology
- Thromboxane B2/metabolism
- Time Factors
- Transfection/methods
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Affiliation(s)
- Santosh Ramamurthy
- Department of Cellular and Molecular Pharmacology, University of Illinois at Chicago College of Medicine, Chicago, IL 60612-7343, USA
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30
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Fillon S, Soulis K, Rajasekaran S, Benedict-Hamilton H, Radin JN, Orihuela CJ, El Kasmi KC, Murti G, Kaushal D, Gaber MW, Weber JR, Murray PJ, Tuomanen EI. Platelet-activating factor receptor and innate immunity: uptake of gram-positive bacterial cell wall into host cells and cell-specific pathophysiology. THE JOURNAL OF IMMUNOLOGY 2006; 177:6182-91. [PMID: 17056547 DOI: 10.4049/jimmunol.177.9.6182] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The current model of innate immune recognition of Gram-positive bacteria suggests that the bacterial cell wall interacts with host recognition proteins such as TLRs and Nod proteins. We describe an additional recognition system mediated by the platelet-activating factor receptor (PAFr) and directed to the pathogen-associated molecular pattern phosphorylcholine that results in the uptake of bacterial components into host cells. Intravascular choline-containing cell walls bound to endothelial cells and caused rapid lethality in wild-type, Tlr2(-/-), and Nod2(-/-) mice but not in Pafr(-/-) mice. The cell wall exited the vasculature into the heart and brain, accumulating within endothelial cells, cardiomyocytes, and neurons in a PAFr-dependent way. Physiological consequences of the cell wall/PAFr interaction were cell specific, being noninflammatory in endothelial cells and neurons but causing a rapid loss of cardiomyocyte contractility that contributed to death. Thus, PAFr shepherds phosphorylcholine-containing bacterial components such as the cell wall into host cells from where the response ranges from quiescence to severe pathophysiology.
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Affiliation(s)
- Sophie Fillon
- Department of Infectious Diseases, St. Jude Children's Research Hospital, 332 North Lauderdale Street, Memphis, TN 38105, USA
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31
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Higa R, González E, Pustovrh MC, White V, Capobianco E, Martínez N, Jawerbaum A. PPARδ and its activator PGI2 are reduced in diabetic embryopathy: involvement of PPARδ activation in lipid metabolic and signalling pathways in rat embryo early organogenesis. ACTA ACUST UNITED AC 2006; 13:103-10. [PMID: 17148578 DOI: 10.1093/molehr/gal104] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Maternal diabetes significantly increases the risk of congenital malformations, and the mechanisms involved are not yet clarified. This study was designed to address peroxisome proliferator-activated receptor delta (PPARdelta) involvement in diabetic embryopathy. We investigated the concentrations of PPARdelta and its endogenous agonist prostaglandin (PG)I(2), as well as the effect of PPARdelta activation on lipid metabolism and PGE(2) concentrations in embryos from control and streptozotocin-induced diabetic rats during early organogenesis. Embryos from diabetic rats showed decreased concentrations of PPARdelta and its endogenous agonist PGI(2) when compared with controls. In embryos from control rats, the addition of the PPARdelta activators (cPGI(2) and PGA(1)) increased embryonic phospholipid levels and de novo phospholipid synthesis studied using (14)C-acetate as a tracer. PGE(2) formed from arachidonate released from phospholipid stores was also up-regulated by PPARdelta activators. In embryos from diabetic rats, reduced phospholipid synthesis and PGE(2) content were observed, and clearly up-regulated by cPGI(2) additions to values similar to those found in control embryos. These data suggest that PPARdelta may play an important role in lipid metabolic and signalling pathways during embryo organogenesis, developmental pathways that are altered in embryos from diabetic rats, possibly as a result of a reduction in levels of PPARdelta and its endogenous activator PGI(2).
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Affiliation(s)
- R Higa
- Laboratory of Reproduction and Metabolism, CEFYBO-CONICET, School of Medicine, University of Buenos Aires, Buenos Aires, Argentina
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Das S, Skomorovska-Prokvolit Y, Wang FZ, Pellett PE. Infection-dependent nuclear localization of US17, a member of the US12 family of human cytomegalovirus-encoded seven-transmembrane proteins. J Virol 2006; 80:1191-203. [PMID: 16414996 PMCID: PMC1346967 DOI: 10.1128/jvi.80.3.1191-1203.2006] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The human cytomegalovirus (HCMV) US12 gene family is a group of predicted seven-transmembrane, G-protein-coupled receptor-related proteins, about which little is known. Specific rabbit polyclonal antibodies detected US17 and US18 beginning 54 and 36 h after infection, respectively, with expression of both proteins dependent on viral DNA synthesis. While US14 and US18 are expressed exclusively in the cytoplasm, we unexpectedly found abundant expression of US17 in both the cytoplasm and nucleoplasm. N- and C-terminally tagged versions of US17 were readily detected in the cytoplasm of transfected mammalian cells, but not in nuclei, suggesting that nuclear localization involves other viral proteins or an infection-triggered cellular process. There was no specific colocalization between US17 and other nuclear expressed HCMV-encoded proteins (IE-2, DNA polymerase processivity factor, and pp28/UL99). To determine whether the observed nuclear localization might be the product of a process by which a soluble C-terminal segment of the full-length protein is expressed, we constructed a recombinant virus that incorporates a synthetic epitope at its N terminus, which in conjunction with the antipeptide antibody that targets its predicted cytoplasmic C-terminal segment, enables simultaneous independent detection of both termini. In cells infected with the recombinant, the US17 N and C termini had limited colocalization, with the N-terminal segment not detected in nuclei, supporting the segmentation hypothesis. Consistent with this, a fragment with an apparent molecular size of 10 kDa was detected by immunoblotting. We have identified the first viral example of a seven-transmembrane protein that is either segmented or expressed in nuclei. Further study will be required to learn the mechanism by which this occurs and the function of the nuclear localizing segment. This likely represents yet another mechanism by which a virus has hijacked or modified cellular regulatory pathways for its benefit.
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Affiliation(s)
- Subhendu Das
- Lerner Research Institute, Cleveland Clinic Foundation, 9500 Euclid Avenue NN10, Cleveland, OH 44195, USA
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