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Alexander EK. Novel Genomic Roadmaps and Their Clinical Translation Ahead. J Clin Endocrinol Metab 2022; 107:e886-e887. [PMID: 34131747 PMCID: PMC8764213 DOI: 10.1210/clinem/dgab423] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Indexed: 11/22/2022]
Affiliation(s)
- Erik K Alexander
- Chief, Thyroid Section, Brigham & Women’s Hospital; Professor of Medicine, Harvard Medical School, Boston, MA 02115, USA
- Correspondence: Erik K. Alexander, MD, Brigham and Women’s Hospital and Harvard Medical School, Boston, MA, USA.
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2
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Abstract
Constitutive receptor activity/inverse agonism and functional selectivity/biased agonism are 2 concepts in contemporary pharmacology that have major implications for the use of drugs in medicine and research as well as for the processes of new drug development. Traditional receptor theory postulated that receptors in a population are quiescent unless activated by a ligand. Within this framework ligands could act as agonists with various degrees of intrinsic efficacy, or as antagonists with zero intrinsic efficacy. We now know that receptors can be active without an activating ligand and thus display "constitutive" activity. As a result, a new class of ligand was discovered that can reduce the constitutive activity of a receptor. These ligands produce the opposite effect of an agonist and are called inverse agonists. The second topic discussed is functional selectivity, also commonly referred to as biased agonism. Traditional receptor theory also posited that intrinsic efficacy is a single drug property independent of the system in which the drug acts. However, we now know that a drug, acting at a single receptor subtype, can have multiple intrinsic efficacies that differ depending on which of the multiple responses coupled to a receptor is measured. Thus, a drug can be simultaneously an agonist, an antagonist, and an inverse agonist acting at the same receptor. This means that drugs have an additional level of selectivity (signaling selectivity or "functional selectivity") beyond the traditional receptor selectivity. Both inverse agonism and functional selectivity need to be considered when drugs are used as medicines or as research tools.
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Affiliation(s)
- Kelly A Berg
- Department of Pharmacology, University of Texas Health, San Antonio, Texas
| | - William P Clarke
- Department of Pharmacology, University of Texas Health, San Antonio, Texas,Correspondence: William P. Clarke, PhD, Department of Pharmacology, Mail Stop 7764, UT Health at San Antonio, 7703 Floyd Curl Drive, San Antonio, TX 78229 ()
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3
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Kuzel AR, Lodhi MU, Rahim M. Classic and Non-Classic Features in Pseudohypoparathyroidism: Case Study and Brief Literature Review. Cureus 2017; 9:e1878. [PMID: 29387507 PMCID: PMC5786345 DOI: 10.7759/cureus.1878] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2017] [Accepted: 11/26/2017] [Indexed: 11/05/2022] Open
Abstract
Pseudohypoparathyroidism is a rare condition that is due to a defect in the stimulatory G-protein coupled receptor, resulting in end-organ resistance to parathyroid hormone. Hereditary forms of pseudohypoparathyroidism present with certain classic features such as obesity, short stature, brachydactyly, and intellectual disability. Constellation of these physical features is known as Albright's hereditary osteodystrophy. In this case, 41-year-old male presented with the classic features of pseudohypoparathyroidism and with 59 lbs weight gain over six months. It was determined that the cause of the patient's weight gain was due to concomitant hypothyroidism, which is a common association. There are several non-classic features and associated pathologies associated with pseudohypoparathyroidism. These conditions should be regularly screened for and assessed when a patient presents with pseudohypoparathyroidism.
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Affiliation(s)
- Aaron R Kuzel
- Department of Emergency Medicine, Lincoln Memorial University-Debusk College of Osteopathic Medicine
| | | | - Mustafa Rahim
- Assistant Clinical Professor of Internal Medicine, West Virginia University School of Medicine
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4
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O'Neill J, McMahon SB, Undem BJ. Chronic cough and pain: Janus faces in sensory neurobiology? Pulm Pharmacol Ther 2013; 26:476-85. [PMID: 23831712 DOI: 10.1016/j.pupt.2013.06.010] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/21/2013] [Revised: 06/20/2013] [Accepted: 06/26/2013] [Indexed: 10/26/2022]
Abstract
Both chronic cough and chronic pain are critical clinical issues in which a large number of patients remain unsatisfied with available treatments. These conditions have considerable effects on sufferers' quality of life, who often show co-morbidities such as anxiety and depression. There is therefore a pressing need to find new effective therapies. The basic neurobiological mechanisms and pathologies of these two conditions show substantial homologies. However, whilst chronic pain has received a great deal of attention over the last few decades, the same cannot be said for the neurological underpinnings of chronic cough. There is a substantial literature around mechanisms of chronic pain which is likely to be useful in advancing knowledge about the pathologies of chronic cough. Here we compare the basic pain and cough pathways, in addition to the clinical features and possible pathophysiologies of each; including mechanisms of peripheral and central sensitisation which may underlie symptoms such as hyperalgesia and allodynia, and hypertussitvity and allotussivity. Due to the substantial overlap that emerges, it is likely that therapies may be effective over both areas.
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Affiliation(s)
- Jessica O'Neill
- Neuroscience, Physiology and Pharmacology, University College London, UK. Jessica.o'
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Mahavadi S, Bhattacharya S, Kim J, Fayed S, Al-Shboul O, Grider JR, Murthy KS. Caveolae-dependent internalization and homologous desensitization of VIP/PACAP receptor, VPAC₂, in gastrointestinal smooth muscle. Peptides 2013; 43:137-45. [PMID: 23499767 PMCID: PMC4026926 DOI: 10.1016/j.peptides.2013.03.008] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/12/2012] [Revised: 03/06/2013] [Accepted: 03/07/2013] [Indexed: 12/18/2022]
Abstract
The main membrane proteins of caveolae (caveolin-1, -2 and -3) oligomerize within lipid rich domains to form regular invaginations of smooth muscle plasma membrane and participate in receptor internalization and desensitization independent of clathrin-coated vesicle endocytosis. We have previously shown that Gs-coupled VIP/PACAP receptors, VPAC2, predominantly expressed in smooth muscle cells of the gut, are exclusively phosphorylated by GRK2 leading to receptor internalization and desensitization. Herein, we characterized the role of caveolin-1 in VPAC2 receptor internalization and desensitization in gastric smooth muscle using three approaches: (i) methyl β-cyclodextrin (MβCD) to deplete cholesterol and disrupt caveolae in dispersed muscle cells, (ii) caveolin-1 siRNA to suppress caveolin-1 expression in cultured muscle cells, and (iii) caveolin-1 knockout mice (caveolin-1(-/-)). Pretreatment of gastric muscle cells with VIP stimulated tyrosine phosphorylation of caveolin-1, and induced VPAC2 receptor internalization (measured as decrease in (125)I-VIP binding after pretreatment) and desensitization (measured as decrease in VIP-induced cAMP formation after pretreatment). Caveolin-1 phosphorylation, and VPAC2 receptor internalization and desensitization were blocked by disruption of caveolae with MβCD, suppression of caveolin-1 with caveolin-1 siRNA or inhibition of Src kinase activity by PP2. Pretreatment with VIP significantly inhibited adenylyl cyclase activity and muscle relaxation in response to subsequent addition of VIP in freshly dispersed muscle cells and in muscle strips isolated from wild type and caveolin-1(-/-) mice; however, the inhibition was significantly attenuated in caveolin-1(-/-) mice. These results suggest that caveolin-1 plays an important role in VPAC2 receptor internalization and desensitization.
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Affiliation(s)
| | | | | | | | | | | | - Karnam S. Murthy
- Corresponding author at: Department of Physiology, Virginia Commonwealth University, Richmond, VA 23298-0551, United States. Tel.: +1 804 828 0029; fax: +1 804 827 0947. (K.S. Murthy)
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6
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Whistler JL. Examining the role of mu opioid receptor endocytosis in the beneficial and side-effects of prolonged opioid use: from a symposium on new concepts in mu-opioid pharmacology. Drug Alcohol Depend 2012; 121:189-204. [PMID: 22226706 PMCID: PMC4224378 DOI: 10.1016/j.drugalcdep.2011.10.031] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/04/2011] [Revised: 10/20/2011] [Accepted: 10/22/2011] [Indexed: 12/31/2022]
Abstract
Opioid drugs remain the gold standard for the treatment of severe pain, both acute/post-surgical and chronic. However, the utility of opioid drugs for the treatment of chronic pain is compromised by the development of analgesic tolerance which, in turn, leads to dose-escalation and increased likelihood of dangerous side effects, including dependence. Consequently, there remains resistance among clinicians and the general population to using opiates for pain management because of risk of "addiction." These fears are not unwarranted. More than 2.5 million people begin abusing opioid painkillers each year, and prescription opioid abuse is now the second most common type of illegal drug use after marijuana. Some abusers become dependent due to recreational use of prescription painkillers. However, many abusers are among the 40 million people suffering from chronic pain, and developed dependence while using the drugs for legitimate purposes. Both of these trends highlight the need to develop opioid therapeutics with a reduced liability to cause tolerance, dependence and addiction. Identifying the ideal properties of opioid drugs that would retain analgesia but reduce these side-effects has been a goal of my laboratory for more than a decade. During this time, we have proposed the novel hypothesis that opioid drugs that promote desensitization, endocytosis and recycling of the mu-opioid-receptor (MOR) will retain analgesic efficacy, but will have a reduced liability to cause tolerance, dependence and addiction. We have generated substantial data, both pharmacological and genetic to suggest that our hypothesis is a valid one. These data are summarized in this review.
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Affiliation(s)
- Jennifer L. Whistler
- Department of Neurology, Ernest Gallo Clinic and Research Center, University of California, San Francisco, 5858 Horton St. Suite 200, Emeryville, CA 94608, tel: 510 985-3127, fax: 510 985-3101,
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Stockton SD, Devi LA. Functional relevance of μ-δ opioid receptor heteromerization: a role in novel signaling and implications for the treatment of addiction disorders: from a symposium on new concepts in mu-opioid pharmacology. Drug Alcohol Depend 2012; 121:167-72. [PMID: 22115888 PMCID: PMC3288266 DOI: 10.1016/j.drugalcdep.2011.10.025] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/03/2011] [Revised: 07/20/2011] [Accepted: 10/22/2011] [Indexed: 11/28/2022]
Abstract
Morphine and other opiates are among the most widely prescribed and clinically useful medications for the treatment of chronic pain. However, the applicability of these compounds has been severely hampered by the rapid development of tolerance and physical dependence that typically accompanies their repeated use. A growing body of evidence has implicated the regulated functioning of μ-δ opioid receptor heteromers in both the modulation of morphine-mediated antinociception, and in the limitation of undesirable side effects resulting from chronic opiate exposure. Moreover, μ-δ heteromers exhibit unique ligand binding characteristics and signaling properties, indicating that pharmacological targeting of the μ-δ heteromer may represent a novel therapeutic approach for the management of chronic pain and addiction disorders. Therefore, the present review will attempt to summarize the latest relevant findings regarding the regulation and functional characteristics of the μ-δ heteromer both in vitro and in vivo.
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Affiliation(s)
| | - Lakshmi A. Devi
- Corresponding author: , Phone: (212) 241-8345; Fax: (212) 996-7214
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Studer E, Zhou X, Zhao R, Wang Y, Takabe K, Nagahashi M, Pandak WM, Dent P, Spiegel S, Shi R, Xu W, Liu X, Bohdan P, Zhang L, Zhou H, Hylemon PB. Conjugated bile acids activate the sphingosine-1-phosphate receptor 2 in primary rodent hepatocytes. Hepatology 2012; 55:267-76. [PMID: 21932398 PMCID: PMC3245352 DOI: 10.1002/hep.24681] [Citation(s) in RCA: 215] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/26/2011] [Accepted: 08/29/2011] [Indexed: 12/15/2022]
Abstract
Bile acids have been shown to be important regulatory molecules for cells in the liver and gastrointestinal tract. They can activate various cell signaling pathways including extracellular regulated kinase (ERK)1/2 and protein kinase B (AKT) as well as the G-protein-coupled receptor (GPCR) membrane-type bile acid receptor (TGR5/M-BAR). Activation of the ERK1/2 and AKT signaling pathways by conjugated bile acids has been reported to be sensitive to pertussis toxin (PTX) and dominant-negative Gα(i) in primary rodent hepatocytes. However, the GPCRs responsible for activation of these pathways have not been identified. Screening GPCRs in the lipid-activated phylogenetic family (expressed in HEK293 cells) identified sphingosine-1-phosphate receptor 2 (S1P(2) ) as being activated by taurocholate (TCA). TCA, taurodeoxycholic acid (TDCA), tauroursodeoxycholic acid (TUDCA), glycocholic acid (GCA), glycodeoxycholic acid (GDCA), and S1P-induced activation of ERK1/2 and AKT were significantly inhibited by JTE-013, a S1P(2) antagonist, in primary rat hepatocytes. JTE-013 significantly inhibited hepatic ERK1/2 and AKT activation as well as short heterodimeric partner (SHP) mRNA induction by TCA in the chronic bile fistula rat. Knockdown of the expression of S1P(2) by a recombinant lentivirus encoding S1P(2) shRNA markedly inhibited the activation of ERK1/2 and AKT by TCA and S1P in rat primary hepatocytes. Primary hepatocytes prepared from S1P(2) knock out (S1P(2) (-/-) ) mice were significantly blunted in the activation of the ERK1/2 and AKT pathways by TCA. Structural modeling of the S1P receptors indicated that only S1P(2) can accommodate TCA binding. In summary, all these data support the hypothesis that conjugated bile acids activate the ERK1/2 and AKT signaling pathways primarily through S1P(2) in primary rodent hepatocytes.
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Affiliation(s)
- Elaine Studer
- Department of Microbiology and Immunology, Medical College of Virginia Campus, Virginia Commonwealth University, Richmond, Virginia 23298
| | - Xiqiao Zhou
- Department of Microbiology and Immunology, Medical College of Virginia Campus, Virginia Commonwealth University, Richmond, Virginia 23298,Department of Gastroenterology, The First Affiliated Hospital of Nanjing Medical University, Jiangsu, China
| | - Renping Zhao
- Department of Microbiology and Immunology, Medical College of Virginia Campus, Virginia Commonwealth University, Richmond, Virginia 23298,China Pharmaceutical University, Nanjing, China
| | - Yun Wang
- Department of Microbiology and Immunology, Medical College of Virginia Campus, Virginia Commonwealth University, Richmond, Virginia 23298,China Pharmaceutical University, Nanjing, China
| | - Kazuaki Takabe
- Department of Surgery, Medical College of Virginia Campus, Virginia Commonwealth University, Richmond, Virginia 23298
| | - Masayuki Nagahashi
- Department of Surgery, Medical College of Virginia Campus, Virginia Commonwealth University, Richmond, Virginia 23298
| | - William M. Pandak
- McGuire Veterans Affairs Medical Center, Medical College of Virginia Campus, Virginia Commonwealth University, Richmond, Virginia 23298
| | - Paul Dent
- Department of Neurosurgery, Medical College of Virginia Campus, Virginia Commonwealth University, Richmond, Virginia 23298
| | - Sarah Spiegel
- Department of Biochemistry and Molecular Biology, Medical College of Virginia Campus, Virginia Commonwealth University, Richmond, Virginia 23298
| | - Ruihua Shi
- Department of Gastroenterology, The First Affiliated Hospital of Nanjing Medical University, Jiangsu, China
| | - Weiren Xu
- Tianjin Key Laboratory of Molecular Design and Drug Discovery, Tianjin Institute of Pharmaceutical Research, Tianjin China
| | - Xuyuan Liu
- Tianjin Key Laboratory of Molecular Design and Drug Discovery, Tianjin Institute of Pharmaceutical Research, Tianjin China
| | - Pat Bohdan
- Department of Microbiology and Immunology, Medical College of Virginia Campus, Virginia Commonwealth University, Richmond, Virginia 23298
| | | | - Huiping Zhou
- Department of Microbiology and Immunology, Medical College of Virginia Campus, Virginia Commonwealth University, Richmond, Virginia 23298,McGuire Veterans Affairs Medical Center, Medical College of Virginia Campus, Virginia Commonwealth University, Richmond, Virginia 23298,Address: To whom correspondence should be addressed: Phillip B. Hylemon, Ph.D., Department of Microbiology and Immunology, Medical College of Virginia Campus-VCU, PO Box 908678, Richmond, VA 23298-0678, Tel. (804) 347-1752; Fax. (804) 828-0676, Or Huiping Zhou, Ph.D, Department of Microbiology and Immunology, Medical College of Virginia Campus-VCU, PO Box 908678, Richmond, VA 23298-0678, Tel. (804)828-6817; Fax. (804) 828-0676,
| | - Phillip B. Hylemon
- Department of Microbiology and Immunology, Medical College of Virginia Campus, Virginia Commonwealth University, Richmond, Virginia 23298,McGuire Veterans Affairs Medical Center, Medical College of Virginia Campus, Virginia Commonwealth University, Richmond, Virginia 23298,Address: To whom correspondence should be addressed: Phillip B. Hylemon, Ph.D., Department of Microbiology and Immunology, Medical College of Virginia Campus-VCU, PO Box 908678, Richmond, VA 23298-0678, Tel. (804) 347-1752; Fax. (804) 828-0676, Or Huiping Zhou, Ph.D, Department of Microbiology and Immunology, Medical College of Virginia Campus-VCU, PO Box 908678, Richmond, VA 23298-0678, Tel. (804)828-6817; Fax. (804) 828-0676,
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Thaker TM, Kaya AI, Preininger AM, Hamm HE, Iverson TM. Allosteric mechanisms of G protein-Coupled Receptor signaling: a structural perspective. Methods Mol Biol 2012; 796:133-74. [PMID: 22052489 DOI: 10.1007/978-1-61779-334-9_8] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/10/2023]
Abstract
G protein-Coupled Receptors (GPCRs) use a complex series of intramolecular conformational changes to couple agonist binding to the binding and activation of cognate heterotrimeric G protein (Gαβγ). The mechanisms underlying this long-range activation have been identified using a variety of biochemical and structural approaches and have primarily used visual signal transduction via the GPCR rhodopsin and cognate heterotrimeric G protein transducin (G(t)) as a model system. In this chapter, we review the methods that have revealed allosteric signaling through rhodopsin and transducin. These methods can be applied to a variety of GPCR-mediated signaling pathways.
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Janovick JA, Brothers SP, Cornea A, Bush E, Goulet MT, Ashton WT, Sauer DR, Haviv F, Greer J, Conn PM. Refolding of misfolded mutant GPCR: post-translational pharmacoperone action in vitro. Mol Cell Endocrinol 2007; 272:77-85. [PMID: 17555869 PMCID: PMC2169380 DOI: 10.1016/j.mce.2007.04.012] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/10/2006] [Revised: 04/19/2007] [Accepted: 04/21/2007] [Indexed: 01/01/2023]
Abstract
All reported GnRH receptor mutants (causing human hypogonadotropic hypogonadism) are misfolded proteins that cannot traffic to the plasma membrane. Pharmacoperones correct misfolding and rescue mutants, routing them to the plasma membrane where they regain function. Because pharmacoperones are often peptidomimetic antagonists, these must be removed for receptor function after rescue; in vivo this necessitates pulsatile pharmacoperone administration. As an antecedent to in vivo studies, we determined whether pharmacoperones need to be present at the time of synthesis or whether previously misfolded proteins could be refolded and rescued. Accordingly, we blocked either protein synthesis or intra-cellular transport. Biochemical and morphological studies using 12 mutants and 10 pharmacoperones representing three different chemical classes show that previously synthesized mutant proteins, retained by the quality control system (QCS), are rescued by pharmacoperones, showing that pharmacoperone administration in vivo likely need not consider whether the target protein is being synthesized at the time of drug administration.
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Affiliation(s)
- Jo Ann Janovick
- Divisions of Neuroscience and Reproductive Sciences, Oregon National Primate Research Center, Beaverton OR 97006
| | - Shaun P. Brothers
- Divisions of Neuroscience and Reproductive Sciences, Oregon National Primate Research Center, Beaverton OR 97006
- Department of Physiology and Pharmacology, Oregon Health and Science University, Portland OR 97239
| | - Anda Cornea
- Divisions of Neuroscience and Reproductive Sciences, Oregon National Primate Research Center, Beaverton OR 97006
| | | | | | | | | | | | | | - P. Michael Conn
- Divisions of Neuroscience and Reproductive Sciences, Oregon National Primate Research Center, Beaverton OR 97006
- Department of Physiology and Pharmacology, Oregon Health and Science University, Portland OR 97239
- Department of Cell and Developmental Biology, Oregon Health and Science University, Portland OR 97239
- Corresponding Author: Dr. P. M. Conn, ONPRC/OHSU, 505 NW 185 Avenue, Beaverton, OR 97006, Phone: 503-690-5297, FAX: 503-690-5569,
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Mills JS. Peptides derived from HIV-1, HIV-2, Ebola virus, SARS coronavirus and coronavirus 229E exhibit high affinity binding to the formyl peptide receptor. Biochim Biophys Acta Mol Basis Dis 2006; 1762:693-703. [PMID: 16842982 PMCID: PMC2075610 DOI: 10.1016/j.bbadis.2006.05.008] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2006] [Revised: 05/25/2006] [Accepted: 05/26/2006] [Indexed: 11/16/2022]
Abstract
Peptides derived from the membrane proximal region of fusion proteins of human immunodeficiency viruses 1 and 2, Coronavirus 229 E, severe acute respiratory syndrome coronavirus and Ebola virus were all potent antagonists of the formyl peptide receptor expressed in Chinese hamster ovary cells. Binding of viral peptides was affected by the naturally occurring polymorphisms at residues 190 and 192, which are located at second extracellular loop-transmembrane helix 5 interface. Substitution of R190 with W190 enhanced the affinity for a severe acute respiratory syndrome coronavirus peptide 6 fold but reduced the affinity for N-formyl-Nle-Leu-Phe by 2.5 fold. A 12 mer peptide derived from coronavirus 229E (ETYIKPWWVWL) was the most potent antagonist of the formyl peptide receptor W190 with a K(i) of 230 nM. Fluorescently labeled ETYIKPWWVWL was effectively internalized by all three variants with EC(50) of approximately 25 nM. An HKU-1 coronavirus peptide, MYVKWPWYVWL, was a potent antagonist but N-formyl-MYVKWPWYVWL was a potent agonist. ETYIKPWWVWL did not stimulate GTPgammaS binding but inhibited the stimulation by formyl-NleLeuPhe. It also blocked beta arrestin translocation and receptor downregulation induced by formyl-Nle-Leu-Phe. This indicates that formyl peptide receptor may be important in viral infections and that variations in its sequence among individuals may affect their likelihood of viral and bacterial infections.
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Key Words
- fpr, formyl peptide receptor
- cho s, chinese hamster ovary cells designed for suspension culture
- hrsv, human respiratory syncytial virus
- fiv, feline immunodeficiency virus
- fmlf, n-formyl-methionyl-leucyl-phenylalanine
- aids, acquired immunodeficiency syndrome
- siv, simian immunodeficiency virus
- hiv, human immunodeficiency virus
- sars, severe acute respiratory syndrome
- gp-41, 41 kilodalton glycoprotein
- hr, heptade repeat
- fitc, fluorescein isothiocyanate
- formyl-nle–leu–phe–nle–tyr–lys–fitc, formyl-nle–leu–phe–nle–tyr–lys labeled at the lys residue with fluorescein isothiocyanate
- formyl-nle–leu–phe–nle–tyr–lys–alexa fluor, formyl-nle–leu–phe–nle–tyr–lys labeled at the lys residue with alexa fluor n-hydroxy-succinimide
- etyik-(alexa fluor)wpwwvwl, etyikwpwwvwl labeled with alexa fluor 488 n-hydroxy-succinimide
- gtpγs, guanosine 5′-3-o-(thio)triphosphate
- tmh, transmembrane helix
- fprl1, formyl peptide like receptor 1
- fprl2, formyl peptide receptor like 2
- virus
- signal transduction
- g protein coupled receptor
- polymorphism
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Affiliation(s)
- John S Mills
- 109 Lewis Hall, Montana State University, Bozeman, MT 59717-3520, USA.
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Abstract
1. Prostaglandins play a major role in maintaining ductal patency in utero. Ductal tone is regulated by both locally released and circulating vasodilatory prostaglandins. In infants with ductus arteriosus-dependent congenital heart disease, ductal patency is maintained by intravenous administration of prostaglandin (PG) E(1). Little information is available regarding the expression of prostaglandin receptors in man. 2. By means of RT-PCR and immunohistochemistry we studied the expression of the PGI(2) receptor (IP), the four different PGE(2) receptors (EP1, EP2, EP3 and EP4), and the receptors for thromboxane (Tx) A(2) (TP), PGD(2) (DP) and PGF(2alpha) (FP) in the ductus arteriosus of three newborn infants with ductus arteriosus-dependent congenital heart disease and intravenous infusion of PGE(1) and of one 8 month old child with a patent ductus arteriosus. 3. The EP3, EP4, FP, IP and TP receptor were markedly expressed at the mRNA and protein level, whereas the EP2 receptor was weakly expressed and the EP1 receptor was detected in two out of four tissue specimens only. The DP receptor was not detected in any of the samples. The most pronounced expression, which was located in the media of the ductus arteriosus, was observed for the EP4 and TP receptors followed by IP and FP receptor protein. 4. These data indicate that ductal patency during the infusion of PGE(1) in infants with ductus arteriosus-dependent congenital heart disease might be mediated by the EP4 and IP receptor. The data further suggest that a heterogeneous population of prostanoid receptors may contribute to the regulation of ductus arteriosus tone in humans.
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Affiliation(s)
- Andreas Leonhardt
- Department of Pediatrics, Philipp's University, 35033 Marburg, Germany
| | - Alexander Glaser
- Department of Pediatrics, Philipp's University, 35033 Marburg, Germany
| | - Markus Wegmann
- Department of Pediatrics, Philipp's University, 35033 Marburg, Germany
| | - Dietmar Schranz
- Department of Pediatrics, Philipp's University, 35033 Marburg, Germany
| | | | - Rolf Nüsing
- Department of Pediatrics, Philipp's University, 35033 Marburg, Germany
- Author for correspondence:
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Abstract
The gene encoding the human muscarinic receptor, type 1 (CHRM1), was genotyped from 245 samples of the Coriell Collection (Coriell Institute for Medical Research, Camden, NJ). Fifteen single nucleotide polymorphisms (SNPs) were discovered, 9 of which are located in the coding region of the receptor. Of these, 8 represent synonymous SNPs, indicating that CHRM1 is highly conserved in humans. Only a single allele was found to contain a nonsynonymous SNP, which encodes an amino acid change of Cys to Arg at position 417. This may have functional consequences because a C417S point mutation in rat M1 was previously shown to affect receptor binding and coupling. Furthermore, 0 of 4 SNPs within CHRM1 previously deduced from sequencing of the human genome were found in this study despite a prediction that a majority of such inferred SNPs are accurate. The consensus sequence of CHRM1 obtained in our study differs from the deposited reference sequence (AC NM_000738) in 2 adjacent nucleotides, leading to a V173M change, suggesting a sequencing error in the reference sequence. The extraordinary sequence conservation of the CHRM1 gene-coding region was unexpected as M1-knockout mice show only minimal functional impairments.
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Affiliation(s)
- Julie L. Lucas
- Department of Biopharmaceutical Sciences, University of California San Francisco, 94143-0446 San Francisco, CA
- Department of Pharmaceutical Chemistry, University of California San Francisco, 94143-0446 San Francisco, CA
| | - Wolfgang Sadee
- Department of Biopharmaceutical Sciences, University of California San Francisco, 94143-0446 San Francisco, CA
- Department of Pharmaceutical Chemistry, University of California San Francisco, 94143-0446 San Francisco, CA
| | - Joseph A. DeYoung
- Genomics Core Facility, Program in Human Genetics, Department of Biochemistry and Biophysics, University of California San Francisco, 94143-0984 San Francisco, CA
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Green A, Walls S, Wise A, Green RH, Martin AK, Marshall FH. Characterization of [(3)H]-CGP54626A binding to heterodimeric GABA(B) receptors stably expressed in mammalian cells. Br J Pharmacol 2000; 131:1766-74. [PMID: 11139457 PMCID: PMC1572513 DOI: 10.1038/sj.bjp.0703755] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Functional human GABA(B(1a,2)) and GABA(B(1b,2)) receptors have been stably expressed in mammalian CHO K1 cells. Detailed characterization of GABA(B) ligand binding at each of the receptors has been compared using [(3)H]-CGP54626A. In cell membranes fractions, [(3)H]-CGP54626A bound to a single site with a K(D) of 1. 51+/-1.12 nM, B(max) of 2.02+/-0.17 pmoles mg protein(-1) and 0. 86+/-0.20 nM, B(max) of 5.19+/-0.57 pmoles mg protein(-1) for GABA(B(1a,2)) and GABA(B(1b,2)) respectively. In competition binding assays the rank order was identical for both GABA(B) receptors. For known GABA(B) agonists the rank order was CGP27492>SKF97541=CGP46381>GABA>Baclofen and for GABA(B) antagonists the rank order was CGP54262A>CGP55845>CGP52432>SCH 50911>CGP51176>CGP36742=CGP35348 > or =2-OH Saclofen > or =ABPA. The allosteric effect of calcium cations was also investigated. The effect of removal of CaCl(2) from the binding assay conditions was ligand dependent to either cause a decrease in ligand affinity or to have no significant effect. However, these effects were similar for both GABA(B) receptors. A whole cell, scintillation proximity binding assay was used to determine agonist affinity at exclusively heterodimeric GABA(B) receptors. In competition assays, the rank order was the same for both GABA(B(1a,2)) and GABA(B(1b,2)) and consistent with that seen with cell membrane fractions. These data suggest that, in terms of ligand binding, the currently identified isoforms of the GABA(B) receptor are pharmacologically indistinguishable.
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Affiliation(s)
- A Green
- Receptor Systems Unit, Glaxo Wellcome Research and Development, Medicines Research Centre, Gunnels Wood Road, Stevenage, Hertfordshire, SG1 2NY.
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