scholarly journals Inhibition of Ebola and Marburg Virus Entry by G Protein-Coupled Receptor Antagonists

2015 ◽  
Vol 89 (19) ◽  
pp. 9932-9938 ◽  
Author(s):  
Han Cheng ◽  
Calli M. Lear-Rooney ◽  
Lisa Johansen ◽  
Elizabeth Varhegyi ◽  
Zheng W. Chen ◽  
...  
Keyword(s):  
Antiviral Activity ◽  
G Protein ◽  
High Mortality ◽  
Ebola Virus ◽  
Critical Role ◽  
Marburg Virus ◽  
Severe Illness ◽  
G Protein Coupled Receptor ◽  
Chemical Library ◽  
G Protein Coupled

ABSTRACTFiloviruses, consisting of Ebola virus (EBOV) and Marburg virus (MARV), are among the most lethal infectious threats to mankind. Infections by these viruses can cause severe hemorrhagic fevers in humans and nonhuman primates with high mortality rates. Since there is currently no vaccine or antiviral therapy approved for humans, there is an urgent need to develop prophylactic and therapeutic options for use during filoviral outbreaks and bioterrorist attacks. One of the ideal targets against filoviral infection and diseases is at the entry step, which is mediated by the filoviral glycoprotein (GP). In this report, we screened a chemical library of small molecules and identified numerous inhibitors, which are known G protein-coupled receptor (GPCR) antagonists targeting different GPCRs, including histamine receptors, 5-HT (serotonin) receptors, muscarinic acetylcholine receptor, and adrenergic receptor. These inhibitors can effectively block replication of both infectious EBOV and MARV, indicating a broad antiviral activity of the GPCR antagonists. The time-of-addition experiment and microscopic studies suggest that GPCR antagonists block filoviral entry at a step following the initial attachment but prior to viral/cell membrane fusion. These results strongly suggest that GPCRs play a critical role in filoviral entry and GPCR antagonists can be developed as an effective anti-EBOV/MARV therapy.IMPORTANCEInfection of Ebola virus and Marburg virus can cause severe illness in humans with a high mortality rate, and currently there is no FDA-approved vaccine or therapeutic treatment available. The 2013-2015 epidemic in West Africa underscores a lack of our understanding in the infection and pathogenesis of these viruses and the urgency of drug discovery and development. In this study, we have identified numerous inhibitors that are known G protein-coupled receptor (GPCR) antagonists targeting different GPCRs. These inhibitors can effectively block replication of both infectious EBOV and MARV, indicating a broad antiviral activity of the GPCR antagonists. Our results strongly suggest that GPCRs play a critical role in filoviral entry and GPCR antagonists can be developed as an effective anti-EBOV/MARV therapy.

scholarly journals Acute loss of Cell–Cell Communication Caused by G Protein–coupled Receptors: A Critical Role for c-Src

1998 ◽  
Vol 140 (5) ◽  
pp. 1199-1209 ◽  
Author(s):  
Friso R. Postma ◽  
Trudi Hengeveld ◽  
Jacqueline Alblas ◽  
Ben N.G. Giepmans ◽  
Gerben C.M. Zondag ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Gap Junction ◽  
G Protein ◽  
Critical Role ◽  
Cell Communication ◽  
G Protein Coupled Receptors ◽  
G Protein Coupled Receptor ◽  
Junction Protein ◽  
G Protein Coupled ◽  
Cell Cell

Gap junctions mediate cell–cell communication in almost all tissues, but little is known about their regulation by physiological stimuli. Using a novel single-electrode technique, together with dye coupling studies, we show that in cells expressing gap junction protein connexin43, cell–cell communication is rapidly disrupted by G protein–coupled receptor agonists, notably lysophosphatidic acid, thrombin, and neuropeptides. In the continuous presence of agonist, junctional communication fully recovers within 1–2 h of receptor stimulation. In contrast, a desensitization-defective G protein–coupled receptor mediates prolonged uncoupling, indicating that recovery of communication is controlled, at least in part, by receptor desensitization. Agonist-induced gap junction closure consistently follows inositol lipid breakdown and membrane depolarization and coincides with Rho-mediated cytoskeletal remodeling. However, we find that gap junction closure is independent of Ca2+, protein kinase C, mitogen-activated protein kinase, or membrane potential, and requires neither Rho nor Ras activation. Gap junction closure is prevented by tyrphostins, by dominant-negative c-Src, and in Src-deficient cells. Thus, G protein–coupled receptors use a Src tyrosine kinase pathway to transiently inhibit connexin43-based cell–cell communication.

scholarly journals Identification of Physiologically Active Substances as Novel Ligands for MRGPRD

2012 ◽  
Vol 2012 ◽  
pp. 1-9 ◽  
Author(s):  
Makiko Uno ◽  
Satoko Nishimura ◽  
Keisuke Fukuchi ◽  
Yasuyuki Kaneta ◽  
Yoko Oda ◽  
...  
Keyword(s):  
G Protein ◽  
Anticancer Agent ◽  
The Novel ◽  
G Protein Coupled Receptor ◽  
Chemical Library ◽  
Beta Alanine ◽  
Physiologically Active Substances ◽  
Small Molecule Compound ◽  
G Protein Coupled ◽  
Active Substances

Mas-related G-protein coupled receptor member D (MRGPRD) is a G protein-coupled receptor (GPCR) which belongs to the Mas-related GPCRs expressed in the dorsal root ganglia (DRG). In this study, we investigated two novel ligands in addition to beta-alanine: (1) beta-aminoisobutyric acid, a physiologically active substance, with which possible relation to tumors has been seen together with beta-alanine; (2) diethylstilbestrol, a synthetic estrogen hormone. In addition to the novel ligands, we found that transfection of MRGPRD leads fibroblast cells to form spheroids, which would be related to oncogenicity. To understand the MRGPRD novel character, oncogenicity, a large chemical library was screened in order to obtain MRGPRD antagonists to utilize in exploring the character. The antagonist in turn inhibited the spheroid proliferation that is dependent on MRGPRD signaling as well as MRGPRD signals activated by beta-alanine. The antagonist, a small-molecule compound we found in this study, is a potential anticancer agent.

scholarly journals Critical Role for the Second Extracellular Loop in the Binding of Both Orthosteric and Allosteric G Protein-coupled Receptor Ligands

2007 ◽  
Vol 282 (35) ◽  
pp. 25677-25686 ◽  
Author(s):  
Vimesh A. Avlani ◽  
Karen J. Gregory ◽  
Craig J. Morton ◽  
Michael W. Parker ◽  
Patrick M. Sexton ◽  
...  
Keyword(s):  
G Protein ◽  
Critical Role ◽  
Extracellular Loop ◽  
Receptor Ligands ◽  
G Protein Coupled Receptor ◽  
G Protein Coupled

scholarly journals Estrogen Signaling Characteristics of Atlantic Croaker G Protein-Coupled Receptor 30 (GPR30) and Evidence It Is Involved in Maintenance of Oocyte Meiotic Arrest

Endocrinology ◽  
2008 ◽  
Vol 149 (7) ◽  
pp. 3410-3426 ◽  
Author(s):  
Yefei Pang ◽  
Jing Dong ◽  
Peter Thomas
Keyword(s):  
G Protein ◽  
Plasma Membranes ◽  
Critical Role ◽  
Hek293 Cells ◽  
Atlantic Croaker ◽  
Estrogen Signaling ◽  
G Protein Coupled Receptor ◽  
Meiotic Arrest ◽  
Transfected Cells ◽  
G Protein Coupled

Human G protein-coupled receptor 30 (GPR30) mediates estradiol-17β (E2) activation of adenylyl cyclase in breast cancer cells and displays E2 binding typical of membrane estrogen receptors (mERs). We identified a mER in Atlantic croaker ovaries with characteristics similar to those of human GPR30. To confirm the proposed role of GPR30 as a mER in this distantly related vertebrate group, we cloned GPR30 from croaker ovaries and examined its distribution, steroid binding, and signaling characteristics. Western blot analysis showed the GPR30 protein (∼40 kDa) is expressed on the plasma membranes of croaker oocytes and HEK293 cells stably transfected with GPR30 cDNA. Plasma membranes prepared from croaker GPR30-transfected cells displayed high-affinity, limited-capacity, and displaceable binding specific for estrogens, characteristic of mERs. Consistent with previous findings with human GPR30, estrogen treatment of plasma membranes from both croaker ovaries and GPR30-transfected cells caused activation of a stimulatory G protein (Gs) resulting in increased cAMP production. Treatment with E2 as well as G-1, a specific GPR30 ligand, significantly reduced both spontaneous and progestin-induced maturation of both croaker and zebrafish oocytes in vitro, suggesting a possible involvement of GPR30 in maintaining oocyte meiotic arrest in these species. Injection of antisense oligonucleotides to GPR30 into zebrafish oocytes blocked the inhibitory effects of estrogen on oocyte maturation, confirming a role for GPR30 in the control of meiotic arrest. These findings further support our previous suggestion that GPR30 is a vertebrate mER. In addition, the results suggest GRP30 may play a critical role in regulating reentry into the meiotic cell cycle in fish oocytes.

scholarly journals Cutting Edge: A Critical Role for the G Protein-Coupled Receptor mFPR2 in Airway Inflammation and Immune Responses

2010 ◽  
Vol 184 (7) ◽  
pp. 3331-3335 ◽  
Author(s):  
Keqiang Chen ◽  
Yingying Le ◽  
Ying Liu ◽  
Wanghua Gong ◽  
Guoguang Ying ◽  
...  
Keyword(s):  
Immune Responses ◽  
Airway Inflammation ◽  
G Protein ◽  
Critical Role ◽  
Cutting Edge ◽  
G Protein Coupled Receptor ◽  
G Protein Coupled

scholarly journals Role of EXT1 and Glycosaminoglycans in the Early Stage of Filovirus Entry

2015 ◽  
Vol 89 (10) ◽  
pp. 5441-5449 ◽  
Author(s):  
Aileen O'Hearn ◽  
Minxiu Wang ◽  
Han Cheng ◽  
Calli M. Lear-Rooney ◽  
Katie Koning ◽  
...  
Keyword(s):  
Mortality Rate ◽  
Heparan Sulfate ◽  
High Mortality ◽  
Ebola Virus ◽  
Cultured Cells ◽  
Therapeutic Potential ◽  
Therapeutic Option ◽  
Marburg Virus ◽  
Severe Illness ◽  
Initial Attachment

ABSTRACTFiloviruses, including both Ebola virus (EBOV) and Marburg virus (MARV), can infect humans and other animals, causing hemorrhagic fever with a high mortality rate. Entry of these viruses into the host is mediated by a single filoviral glycoprotein (GP). GP is composed of two subunits: GP1, which is responsible for attachment and binding to receptor(s) on susceptible cells, and GP2, which mediates viral and cell membrane fusion. Although numerous host factors have been implicated in the entry process, the initial attachment receptor(s) has not been well defined. In this report, we demonstrate that exostosin 1 (EXT1), which is involved in biosynthesis of heparan sulfate (HS), plays a role in filovirus entry. Expression knockdown of EXT1 by small interfering RNAs (siRNAs) impairs GP-mediated pseudoviral entry and that of infectious EBOV and MARV in tissue cultured cells. Furthermore, HS, heparin, and other related glycosaminoglycans (GAGs), to different extents, can bind to and block GP-mediated viral entry and that of infectious filoviruses. These results strongly suggest that HS and other related GAGs are attachment receptors that are utilized by filoviruses for entry and infection. These GAGs may have therapeutic potential in treating EBOV- and MARV-infected patients.IMPORTANCEInfection by Ebola virus and Marburg virus can cause severe illness in humans, with a high mortality rate, and currently there is no FDA-approved vaccine or therapeutic treatment available. The ongoing 2014 outbreak in West Africa underscores a lack of our understanding in the infection and pathogenesis of these viruses and the urgency of drug discovery and development. In this study, we provide several pieces of evidence that demonstrate that heparan sulfate and other closely related glycosaminoglycans are the molecules that are used by filoviruses for initial attachment. Furthermore, we demonstrate that these glycosaminoglycans can block entry of and infection by filoviruses. Thus, this work provides mechanistic insights on the early step of filoviral infection and suggests a possible therapeutic option for diseases caused by filovirus infection.

scholarly journals Structure and dynamics of G protein-coupled receptor–bound ghrelin reveal the critical role of the octanoyl chain

2019 ◽  
Vol 116 (35) ◽  
pp. 17525-17530 ◽  
Author(s):  
Guillaume Ferré ◽  
Maxime Louet ◽  
Oliver Saurel ◽  
Bartholomé Delort ◽  
Georges Czaplicki ◽  
...  
Keyword(s):  
G Protein ◽  
Critical Role ◽  
Conformational Space ◽  
Coarse Grained ◽  
Hydrophobic Core ◽  
G Protein Coupled Receptor ◽  
Growth Hormone Secretagogue Receptor ◽  
Growth Hormone Secretagogue ◽  
Structure And Dynamics ◽  
G Protein Coupled

Ghrelin plays a central role in controlling major biological processes. As for other G protein-coupled receptor (GPCR) peptide agonists, the structure and dynamics of ghrelin bound to its receptor remain obscure. Using a combination of solution-state NMR and molecular modeling, we demonstrate that binding to the growth hormone secretagogue receptor is accompanied by a conformational change in ghrelin that structures its central region, involving the formation of a well-defined hydrophobic core. By comparing its acylated and nonacylated forms, we conclude that the ghrelin octanoyl chain is essential to form the hydrophobic core and promote access of ghrelin to the receptor ligand-binding pocket. The combination of coarse-grained molecular dynamics studies and NMR should prove useful in improving our mechanistic understanding of the complex conformational space explored by a natural peptide agonist when binding to its GPCR. Such information should also facilitate the design of new ghrelin receptor-selective drugs.

scholarly journals G-protein-coupled receptor kinase-2 is a critical regulator of TNFα signaling in colon epithelial cells

2017 ◽  
Vol 474 (14) ◽  
pp. 2301-2313 ◽  
Author(s):  
Michael D. Steury ◽  
Peter C. Lucas ◽  
Laura R. McCabe ◽  
Narayanan Parameswaran
Keyword(s):  
Wound Healing ◽  
Epithelial Cell ◽  
Epithelial Cells ◽  
G Protein ◽  
Critical Role ◽  
Receptor Kinase ◽  
G Protein Coupled Receptor ◽  
G Protein Coupled

G-protein-coupled receptor kinase-2 (GRK2) belongs to the GRK family of serine/threonine protein kinases critical in the regulation of G-protein-coupled receptors. Apart from this canonical role, GRK2 is also involved in several signaling pathways via distinct intracellular interactomes. In the present study, we examined the role of GRK2 in TNFα signaling in colon epithelial cell–biological processes including wound healing, proliferation, apoptosis, and gene expression. Knockdown of GRK2 in the SW480 human colonic cells significantly enhanced TNFα-induced epithelial cell wound healing without any effect on apoptosis/proliferation. Consistent with wound-healing effects, GRK2 knockdown augmented TNFα-induced matrix metalloproteinases (MMPs) 7 and 9, as well as urokinase plasminogen activator (uPA; factors involved in cell migration and wound healing). To assess the mechanism by which GRK2 affects these physiological processes, we examined the role of GRK2 in TNFα-induced MAPK and NF-κB pathways. Our results demonstrate that while GRK2 knockdown inhibited TNFα-induced IκBα phosphorylation, activation of ERK was significantly enhanced in GRK2 knockdown cells. Our results further demonstrate that GRK2 inhibits TNFα-induced ERK activation by inhibiting generation of reactive oxygen species (ROS). Together, these data suggest that GRK2 plays a critical role in TNFα-induced wound healing by modulating MMP7 and 9 and uPA levels via the ROS–ERK pathway. Consistent with in vitro findings, GRK2 heterozygous mice exhibited enhanced intestinal wound healing. Together, our results identify a novel role for GRK2 in TNFα signaling in intestinal epithelial cells.

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