1
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Gumpper RH, Roth BL. Psychedelics: preclinical insights provide directions for future research. Neuropsychopharmacology 2024; 49:119-127. [PMID: 36932180 PMCID: PMC10700551 DOI: 10.1038/s41386-023-01567-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/26/2022] [Revised: 01/30/2023] [Accepted: 02/28/2023] [Indexed: 03/19/2023]
Abstract
Recently, psychedelics have emerged as promising therapeutics for numerous neuropsychiatric disorders. While their potential in the clinic has yet to be fully elucidated, understanding their molecular and biological mechanisms is imperative as these compounds are becoming widely used both in therapeutic and recreational contexts. This review examines the current understanding of basic biology, pharmacology, and structural biology in an attempt to reveal both the knowns and unknowns within the field.
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Affiliation(s)
- Ryan H Gumpper
- Department of Pharmacology, UNC School of Medicine, Chapel Hill, NC, 27514, USA
| | - Bryan L Roth
- Department of Pharmacology, UNC School of Medicine, Chapel Hill, NC, 27514, USA.
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2
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Banushi B, Polito V. A Comprehensive Review of the Current Status of the Cellular Neurobiology of Psychedelics. BIOLOGY 2023; 12:1380. [PMID: 37997979 PMCID: PMC10669348 DOI: 10.3390/biology12111380] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2023] [Revised: 10/26/2023] [Accepted: 10/26/2023] [Indexed: 11/25/2023]
Abstract
Psychedelic substances have gained significant attention in recent years for their potential therapeutic effects on various psychiatric disorders. This review delves into the intricate cellular neurobiology of psychedelics, emphasizing their potential therapeutic applications in addressing the global burden of mental illness. It focuses on contemporary research into the pharmacological and molecular mechanisms underlying these substances, particularly the role of 5-HT2A receptor signaling and the promotion of plasticity through the TrkB-BDNF pathway. The review also discusses how psychedelics affect various receptors and pathways and explores their potential as anti-inflammatory agents. Overall, this research represents a significant development in biomedical sciences with the potential to transform mental health treatments.
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Affiliation(s)
- Blerida Banushi
- Genetics and Genomic Medicine Department, Great Ormond Street Institute of Child Health, University College London, London WC1N 1EH, UK
| | - Vince Polito
- School of Psychological Sciences, Macquarie University, Sydney, NSW 2109, Australia;
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3
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Chiu YT, Deutch AY, Wang W, Schmitz GP, Huang KL, Kocak DD, Llorach P, Bowyer K, Liu B, Sciaky N, Hua K, Chen C, Mott SE, Niehaus J, DiBerto JF, English J, Walsh JJ, Scherrer G, Herman MA, Wu Z, Wetsel WC, Roth BL. A suite of engineered mice for interrogating psychedelic drug actions. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.09.25.559347. [PMID: 37808655 PMCID: PMC10557740 DOI: 10.1101/2023.09.25.559347] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/10/2023]
Abstract
Psychedelic drugs like lysergic acid diethylamide (LSD) and psilocybin have emerged as potentially transformative therapeutics for many neuropsychiatric diseases, including depression, anxiety, post-traumatic stress disorder, migraine, and cluster headaches. LSD and psilocybin exert their psychedelic effects via activation of the 5-hydroxytryptamine 2A receptor (HTR2A). Here we provide a suite of engineered mice useful for clarifying the role of HTR2A and HTR2A-expressing neurons in psychedelic drug actions. We first generated Htr2a-EGFP-CT-IRES-CreERT2 mice (CT:C-terminus) to independently identify both HTR2A-EGFP-CT receptors and HTR2A-containing cells thereby providing a detailed anatomical map of HTR2A and identifying cell types that express HTR2A. We also generated a humanized Htr2a mouse line and an additional constitutive Htr2A-Cre mouse line. Psychedelics induced a variety of known behavioral changes in our mice validating their utility for behavioral studies. Finally, electrophysiology studies revealed that extracellular 5-HT elicited a HTR2A-mediated robust increase in firing of genetically-identified pyramidal neurons--consistent with a plasma membrane localization and mode of action. These mouse lines represent invaluable tools for elucidating the molecular, cellular, pharmacological, physiological, behavioral, and other actions of psychedelic drugs in vivo.
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Affiliation(s)
- Yi-Ting Chiu
- Department of Pharmacology, University of North Carolina at Chapel Hill, NC 27599, USA
| | - Ariel Y. Deutch
- Department of Psychiatry and Behavioral Sciences, Vanderbilt University Medical Center, Nashville, TN, USA
- Department of Pharmacology, Vanderbilt University, Nashville, TN, USA
| | - Wei Wang
- Appel Alzheimer’s Disease Research Institute, Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, New York, 10021, USA
| | - Gavin P Schmitz
- Department of Pharmacology, University of North Carolina at Chapel Hill, NC 27599, USA
| | - Karen Lu Huang
- Department of Pharmacology, University of North Carolina at Chapel Hill, NC 27599, USA
- Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- UNC Neuroscience Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - D. Dewran Kocak
- Department of Pharmacology, University of North Carolina at Chapel Hill, NC 27599, USA
| | - Pierre Llorach
- Department of Pharmacology, University of North Carolina at Chapel Hill, NC 27599, USA
- UNC Neuroscience Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Kasey Bowyer
- Appel Alzheimer’s Disease Research Institute, Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, New York, 10021, USA
| | - Bei Liu
- Department of Pharmacology, University of North Carolina at Chapel Hill, NC 27599, USA
| | - Noah Sciaky
- Department of Pharmacology, University of North Carolina at Chapel Hill, NC 27599, USA
| | - Kunjie Hua
- Department of Pharmacology, University of North Carolina at Chapel Hill, NC 27599, USA
| | - Chongguang Chen
- Center for Substance Abuse Research, Lewis Katz School of Medicine, Temple University, Philadelphia, PA 19140, USA
| | - Sarah E. Mott
- Department of Pharmacology, University of North Carolina at Chapel Hill, NC 27599, USA
| | - Jesse Niehaus
- Department of Pharmacology, University of North Carolina at Chapel Hill, NC 27599, USA
- Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- UNC Neuroscience Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Jeffrey F. DiBerto
- Department of Pharmacology, University of North Carolina at Chapel Hill, NC 27599, USA
| | - Justin English
- Department of Pharmacology, University of North Carolina at Chapel Hill, NC 27599, USA
| | - Jessica J. Walsh
- Department of Pharmacology, University of North Carolina at Chapel Hill, NC 27599, USA
- UNC Neuroscience Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Grégory Scherrer
- Department of Pharmacology, University of North Carolina at Chapel Hill, NC 27599, USA
- Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- UNC Neuroscience Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- New York Stem Cell Foundation ‒ Robertson Investigator, Chapel Hill, NC 27599, USA
| | - Melissa A Herman
- Department of Pharmacology, University of North Carolina at Chapel Hill, NC 27599, USA
- Bowles Center for Alcohol Studies, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
| | - Zhuhao Wu
- Appel Alzheimer’s Disease Research Institute, Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, New York, 10021, USA
| | - William C Wetsel
- Departments of Psychiatry and Behavioral Sciences, Cell Biology, and Neurobiology, Duke University Medical Center, Durham, NC 27710, USA
- Mouse Behavioral and Neuroendocrine Analysis Core Facility, Duke University Medical Center, Durham, NC 27710, USA
| | - Bryan L Roth
- Department of Pharmacology, University of North Carolina at Chapel Hill, NC 27599, USA
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4
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Schmitz GP, Roth BL. G protein-coupled receptors as targets for transformative neuropsychiatric therapeutics. Am J Physiol Cell Physiol 2023; 325:C17-C28. [PMID: 37067459 PMCID: PMC10281788 DOI: 10.1152/ajpcell.00397.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Revised: 03/28/2023] [Accepted: 04/06/2023] [Indexed: 04/18/2023]
Abstract
G protein-coupled receptors (GPCRs) constitute the largest family of druggable genes in the human genome. Even though perhaps 30% of approved medications target GPCRs, they interact with only a small number of them. Here, we consider whether there might be new opportunities for transformative therapeutics for neuropsychiatric disorders by specifically targeting both known and understudied GPCRs. Using psychedelic drugs that target serotonin receptors as an example, we show how recent insights into the structure, function, signaling, and cell biology of these receptors have led to potentially novel therapeutics. We next focus on the possibility that nonpsychedelic 5-HT2A receptor agonists might prove to be safe and rapidly acting antidepressants. Finally, we examine understudied and orphan GPCRs using the MRGPR family of receptors as an example.
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Affiliation(s)
- Gavin P Schmitz
- Department of Pharmacology, UNC Chapel Hill Medical School, Chapel Hill, North Carolina, United States
| | - Bryan L Roth
- Department of Pharmacology, UNC Chapel Hill Medical School, Chapel Hill, North Carolina, United States
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5
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Abstract
Over the past decade, psychedelic compounds have emerged as potentially transformative therapeutics for a variety of intractable neuropsychiatric conditions. However, historically most of the basic science has utilized these compounds as probes to interrogate various endogenous neurotransmitter systems-mainly the serotonin 5-HT2A receptor. With the renewed interest in utilizing these compounds as therapeutics and the explosion in clinical trials, psychedelics have been purported to treat many neuropsychiatric disorders, including depression, cluster headaches, migraines, anxiety, and obsessive-compulsive disorder. It is therefore imperative to understand the biology and pharmacology behind their therapeutic mechanisms as well as expose any potential pitfalls in their widespread use as treatments. This review covers the latest advances in understanding the biological mechanisms, the newest efforts in drug discovery, and potential pitfalls when it comes to utilizing this class of compounds as emerging therapeutics.
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Affiliation(s)
- Bryan L Roth
- Department of Pharmacology, University of North Carolina School of Medicine, Chapel Hill
| | - Ryan H Gumpper
- Department of Pharmacology, University of North Carolina School of Medicine, Chapel Hill
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6
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Kwan AC, Olson DE, Preller KH, Roth BL. The neural basis of psychedelic action. Nat Neurosci 2022; 25:1407-1419. [PMID: 36280799 PMCID: PMC9641582 DOI: 10.1038/s41593-022-01177-4] [Citation(s) in RCA: 81] [Impact Index Per Article: 40.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Accepted: 09/06/2022] [Indexed: 01/13/2023]
Abstract
Psychedelics are serotonin 2A receptor agonists that can lead to profound changes in perception, cognition and mood. In this review, we focus on the basic neurobiology underlying the action of psychedelic drugs. We first discuss chemistry, highlighting the diversity of psychoactive molecules and the principles that govern their potency and pharmacokinetics. We describe the roles of serotonin receptors and their downstream molecular signaling pathways, emphasizing key elements for drug discovery. We consider the impact of psychedelics on neuronal spiking dynamics in several cortical and subcortical regions, along with transcriptional changes and sustained effects on structural plasticity. Finally, we summarize neuroimaging results that pinpoint effects on association cortices and thalamocortical functional connectivity, which inform current theories of psychedelic action. By synthesizing knowledge across the chemical, molecular, neuronal, and network levels, we hope to provide an integrative perspective on the neural mechanisms responsible for the acute and enduring effects of psychedelics on behavior.
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Affiliation(s)
- Alex C. Kwan
- Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY, USA,Department of Psychiatry, Yale University School of Medicine, New Haven, CT, USA,Department of Neuroscience, Yale University School of Medicine, New Haven, CT, USA,Correspondence: ; ; ;
| | - David E. Olson
- Department of Chemistry, University of California, Davis, Davis, CA, USA,Department of Biochemistry & Molecular Medicine, School of Medicine, University of California, Davis, Sacramento, CA, USA,Center for Neuroscience, University of California, Davis, Davis, CA, USA,Correspondence: ; ; ;
| | - Katrin H. Preller
- Department of Psychiatry, Psychotherapy and Psychosomatics, Psychiatric University Hospital, University of Zurich, Zurich, Switzerland.,Correspondence: ; ; ;
| | - Bryan L. Roth
- Department of Pharmacology, School of Medicine, University of North Carolina, Chapel Hill, NC, USA.,Division of Chemical Biology and Medicinal Chemistry, Eshelman School of Pharmacy, University of North Carolina, Chapel Hill, NC, USA.,Psychoactive Drug Screening Program, National Institute of Mental Health, School of Medicine, University of North Carolina, Chapel Hill, NC, USA.,Correspondence: ; ; ;
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7
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Schmitz GP, Jain MK, Slocum ST, Roth BL. 5-HT 2A SNPs Alter the Pharmacological Signaling of Potentially Therapeutic Psychedelics. ACS Chem Neurosci 2022; 13:2386-2398. [PMID: 35894503 DOI: 10.1021/acschemneuro.1c00815] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Serotonin (5-hydroxytryptamine; 5-HT) 2A receptor (5-HT2AR) signaling is essential for the actions of classical psychedelic drugs. In this study, we examined whether sequence variations in the 5-HT2AR gene affect the signaling of four commonly used psychedelic drugs. We examined the in vitro pharmacology of seven non-synonymous single-nucleotide polymorphisms (SNPs), which give rise to Ser12Asn, Thr25Asn, Asp48Asn, Ile197Val4.47, Ala230Thr, Ala447Val, and His452Tyr variant 5-HT2A serotonin receptors. We found that these non-synonymous SNPs exert statistically significant, although modest, effects on the efficacy and potency of four therapeutically relevant psychedelics. Significantly, the in vitro pharmacological effects of the SNP drug actions at 5-HT2AR are drug specific.
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Affiliation(s)
- Gavin P Schmitz
- Department of Pharmacology, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, North Carolina 27599-7365, United States
| | - Manish K Jain
- Department of Pharmacology, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, North Carolina 27599-7365, United States
| | - Samuel T Slocum
- Department of Pharmacology, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, North Carolina 27599-7365, United States
| | - Bryan L Roth
- Department of Pharmacology, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, North Carolina 27599-7365, United States
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8
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McClure-Begley TD, Roth BL. The promises and perils of psychedelic pharmacology for psychiatry. Nat Rev Drug Discov 2022; 21:463-473. [PMID: 35301459 DOI: 10.1038/s41573-022-00421-7] [Citation(s) in RCA: 67] [Impact Index Per Article: 33.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/04/2022] [Indexed: 11/09/2022]
Abstract
Psychedelic drugs including psilocybin, N,N'-dimethyltryptamine (DMT) and lysergic acid diethylamide (LSD) are undergoing a renaissance as potentially useful drugs for various neuropsychiatric diseases, with a rapid onset of therapeutic activity. Notably, phase II trials have shown that psilocybin can produce statistically significant clinical effects following one or two administrations in depression and anxiety. These findings have inspired a 'gold rush' of commercial interest, with nearly 60 companies already formed to explore opportunities for psychedelics in treating diverse diseases. Additionally, these remarkable phenomenological and clinical observations are informing hypotheses about potential molecular mechanisms of action that need elucidation to realize the full potential of this investigative space. In particular, despite compelling evidence that the 5-HT2A receptor is a critical mediator of the behavioural effects of psychedelic drugs, uncertainty remains about which aspects of 5-HT2A receptor activity in the central nervous system are responsible for therapeutic effects and to what degree they can be isolated by developing novel chemical probes with differing specificity and selectivity profiles. Here, we discuss this emerging area of therapeutics, covering both controversies and areas of consensus related to the opportunities and perils of psychedelic and psychedelic-inspired therapeutics. We highlight how basic science breakthroughs can guide the discovery and development of psychedelic-inspired medications with the potential for improved efficacy without hallucinogenic or rewarding actions.
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Affiliation(s)
| | - Bryan L Roth
- Department of Pharmacology, University of North Carolina Chapel Hill School of Medicine, Chapel Hill, NC, USA.
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9
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Abstract
In addition to producing profound subjective effects following acute administration, psychedelic compounds can induce beneficial behavioral changes relevant to the treatment of neuropsychiatric disorders that last long after the compounds have been cleared from the body. One hypothesis with the potential to explain the remarkable enduring effects of psychedelics is related to their abilities to promote structural and functional neuroplasticity in the prefrontal cortex (PFC). A hallmark of many stress-related neuropsychiatric diseases, including depression, post-traumatic stress disorder (PTSD), and addiction, is the atrophy of neurons in the PFC. Psychedelics appear to be particularly effective catalysts for the growth of these key neurons, ultimately leading to restoration of synaptic connectivity in this critical brain region. Furthermore, evidence suggests that the hallucinogenic effects of psychedelics are not directly linked to their ability to promote structural and functional neuroplasticity. If we are to develop improved alternatives to psychedelics for treating neuropsychiatric diseases, we must fully characterize the molecular mechanisms that give rise to psychedelic-induced neuroplasticity. Here, I review our current understanding of the biochemical signaling pathways activated by psychedelics and related neuroplasticity-promoting molecules, with an emphasis on key unanswered questions.
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Affiliation(s)
- David E. Olson
- Department of Chemistry, University of California, Davis, One Shields Avenue, Davis, CA 95616, USA,Department of Biochemistry & Molecular Medicine, School of Medicine, University of California, Davis, 2700 Stockton Blvd, Suite 2102, Sacramento, CA 95817, USA,Center for Neuroscience, University of California, Davis, 1544 Newton Ct, Davis, CA 95618, USA,Corresponding Author: David E. Olson,
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10
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Pottie E, Stove CP. In vitro assays for the functional characterization of (psychedelic) substances at the serotonin receptor 5-HT 2A R. J Neurochem 2022; 162:39-59. [PMID: 34978711 DOI: 10.1111/jnc.15570] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2021] [Revised: 12/24/2021] [Accepted: 12/29/2021] [Indexed: 12/20/2022]
Abstract
Serotonergic psychedelics are substances that induce alterations in mood, perception, and thought, and have the activation of serotonin (5-HT) 2A receptors (5-HT2A Rs) as a main pharmacological mechanism. Besides their appearance on the (illicit) drug market, e.g. as new psychoactive substances, their potential therapeutic application is increasingly explored. This group of substances demonstrates a broad structural variety, leading to insufficiently described structure-activity relationships, hence illustrating the need for better functional characterization. This review therefore elaborates on the in vitro molecular techniques that have been used the most abundantly for the characterization of (psychedelic) 5-HT2A R agonists. More specifically, this review covers assays to monitor the canonical G protein signaling pathway (e.g. measuring G protein recruitment/activation, inositol phosphate accumulation, or Ca2+ mobilization), assays to monitor non-canonical G protein signaling (such as arachidonic acid release), assays to monitor β-arrestin recruitment or signaling, and assays to monitor receptor conformational changes. In particular, focus lies on the mechanism behind the techniques, and the specific advantages and challenges that are associated with these. Additionally, several variables are discussed that one should consider when attempting to compare functional outcomes from different studies, both linked to the specific assay mechanism and linked to its specific execution, as these may heavily impact the assay outcome.
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Affiliation(s)
- Eline Pottie
- Laboratory of Toxicology, Faculty of Pharmaceutical Sciences, Department of Bioanalysis, Ghent University, Ghent, Belgium
| | - Christophe P Stove
- Laboratory of Toxicology, Faculty of Pharmaceutical Sciences, Department of Bioanalysis, Ghent University, Ghent, Belgium
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11
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Slocum ST, DiBerto JF, Roth BL. Molecular insights into psychedelic drug action. J Neurochem 2021; 162:24-38. [PMID: 34797943 DOI: 10.1111/jnc.15540] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Revised: 11/11/2021] [Accepted: 11/11/2021] [Indexed: 12/14/2022]
Abstract
A confluence of factors has renewed interest in the scientific understanding and translational potential of psychedelic drugs such as lysergic acid diethylamide (LSD), mescaline, and psilocybin: the desire for additional approaches to mental health care, incremental progress in basic and clinical research, and the reconsideration and relaxation of existing drug policies. With the United States Food and Drug Administration's designation of psilocybin as a "Breakthrough Therapy" for treatment-resistant depression, a new path has been forged for the conveyance of psychedelics to the clinic. Essential to the further development of such applications, however, is a clearer understanding of how these drugs exert their effects at the molecular level. Here we review the current knowledge regarding the molecular details of psychedelic drug actions and suggest that these discoveries can facilitate new insights into their hallucinogenic and therapeutic mechanisms.
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Affiliation(s)
- Samuel T Slocum
- Department of Pharmacology, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, North Carolina, USA
| | - Jeffrey F DiBerto
- Department of Pharmacology, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, North Carolina, USA
| | - Bryan L Roth
- Department of Pharmacology, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, North Carolina, USA
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12
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De Deurwaerdère P, Bharatiya R, Chagraoui A, Di Giovanni G. Constitutive activity of 5-HT receptors: Factual analysis. Neuropharmacology 2020; 168:107967. [DOI: 10.1016/j.neuropharm.2020.107967] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Revised: 12/26/2019] [Accepted: 01/12/2020] [Indexed: 12/16/2022]
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13
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JC Polyomavirus Entry by Clathrin-Mediated Endocytosis Is Driven by β-Arrestin. J Virol 2019; 93:JVI.01948-18. [PMID: 30700597 DOI: 10.1128/jvi.01948-18] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2018] [Accepted: 01/22/2019] [Indexed: 01/09/2023] Open
Abstract
JC polyomavirus (JCPyV) establishes a persistent, lifelong, asymptomatic infection within the kidney of the majority of the human population. Under conditions of severe immunosuppression or immune modulation, JCPyV can reactivate in the central nervous system (CNS) and cause progressive multifocal leukoencephalopathy (PML), a fatal demyelinating disease. Initiation of infection is mediated through viral attachment to α2,6-sialic acid-containing lactoseries tetrasaccharide c (LSTc) on the surface of host cells. JCPyV internalization is dependent on serotonin 5-hydroxytryptamine subfamily 2 receptors (5-HT2Rs), and entry is thought to occur by clathrin-mediated endocytosis (CME). However, the JCPyV entry process and the cellular factors involved in viral internalization remain poorly understood. Treatment of cells with small-molecule chemical inhibitors and RNA interference of 5-HT2R endocytic machinery, including β-arrestin, clathrin, AP2, and dynamin, significantly reduced JCPyV infection. However, infectivity of the polyomavirus simian virus 40 (SV40) was not affected by CME-specific treatments. Inhibition of clathrin or β-arrestin specifically reduced JCPyV internalization but did not affect viral attachment. Furthermore, mutagenesis of a β-arrestin binding domain (Ala-Ser-Lys) within the intracellular C terminus of 5-HT2AR severely diminished internalization and infection, suggesting that β-arrestin interactions with 5-HT2AR are critical for JCPyV infection and entry. These conclusions illuminate key host factors that regulate clathrin-mediated endocytosis of JCPyV, which is necessary for viral internalization and productive infection.IMPORTANCE Viruses usurp cellular factors to invade host cells. Activation and utilization of these proteins upon initiation of viral infection are therefore required for productive infection and resultant viral disease. The majority of healthy individuals are asymptomatically infected by JC polyomavirus (JCPyV), but if the host immune system is compromised, JCPyV can cause progressive multifocal leukoencephalopathy (PML), a rare, fatal, demyelinating disease. Individuals infected with HIV or taking prolonged immunomodulatory therapies have a heightened risk for developing PML. The cellular proteins and pathways utilized by JCPyV to mediate viral entry are poorly understood. Our findings further characterize how JCPyV utilizes the clathrin-mediated endocytosis pathway to invade host cells. We have identified specific components of this pathway that are necessary for the viral entry process and infection. Collectively, the conclusions increase our understanding of JCPyV infection and pathogenesis and may contribute to the future development of novel therapeutic strategies for PML.
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Chao PK, Chang HF, Ou LC, Chuang JY, Lee PT, Chang WT, Chen SC, Ueng SH, Hsu JTA, Tao PL, Law PY, Loh HH, Yeh SH. Convallatoxin enhance the ligand-induced mu-opioid receptor endocytosis and attenuate morphine antinociceptive tolerance in mice. Sci Rep 2019; 9:2405. [PMID: 30787373 PMCID: PMC6382827 DOI: 10.1038/s41598-019-39555-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2018] [Accepted: 01/07/2019] [Indexed: 11/29/2022] Open
Abstract
Morphine is a unique opioid analgesic that activates the mu-opioid receptor (MOR) without efficiently promoting its endocytosis that may underlie side effects. Our objective was to discover a novel enhancer of ligand-induced MOR endocytosis and determine its effects on analgesia, tolerance and dependence. We used high-throughput screening to identify convallatoxin as an enhancer of ligand-induced MOR endocytosis with high potency and efficacy. Treatment of cells with convallatoxin enhanced morphine-induced MOR endocytosis through an adaptor protein 2 (AP2)/clathrin-dependent mechanism, attenuated morphine-induced phosphorylation of MOR, and diminished desensitization of membrane hyperpolarization. Furthermore, co-treatment with chronic convallatoxin reduced morphine tolerance in animal models of acute thermal pain and chronic inflammatory pain. Acute convallatoxin administration reversed morphine tolerance and dependence in morphine-tolerant mice. These findings suggest convallatoxin are potentially therapeutic for morphine side effects and open a new avenue to study MOR trafficking.
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Affiliation(s)
- Po-Kuan Chao
- Institute of Biotechnology and Pharmaceutical Research, National Health Research Institutes, Zhunan, 35053, Taiwan
| | - Hsiao-Fu Chang
- Institute of Biotechnology and Pharmaceutical Research, National Health Research Institutes, Zhunan, 35053, Taiwan
| | - Li-Chin Ou
- Institute of Biotechnology and Pharmaceutical Research, National Health Research Institutes, Zhunan, 35053, Taiwan
| | - Jian-Ying Chuang
- The PhD Program for Neural Regenerative Medicine, Taipei Medical University, Taipei, 110, Taiwan
| | - Pin-Tse Lee
- Cellular Pathobiology Section, Intramural Research Program, National Institute on Drug Abuse, NIH/DHHS, Baltimore, MD, 21224, USA
| | - Wan-Ting Chang
- Institute of Biotechnology and Pharmaceutical Research, National Health Research Institutes, Zhunan, 35053, Taiwan
| | - Shu-Chun Chen
- Institute of Biotechnology and Pharmaceutical Research, National Health Research Institutes, Zhunan, 35053, Taiwan
| | - Shau-Hua Ueng
- Institute of Biotechnology and Pharmaceutical Research, National Health Research Institutes, Zhunan, 35053, Taiwan
| | - John Tsu-An Hsu
- Institute of Biotechnology and Pharmaceutical Research, National Health Research Institutes, Zhunan, 35053, Taiwan
| | - Pao-Luh Tao
- Center for Neuropsychiatric Research, National Heath Research Institutes, Zhunan, 35053, Taiwan
| | - Ping-Yee Law
- Department of Pharmacology, Medical School University of Minnesota, Minneapolis, MN, 55455-0217, USA
| | - Horace H Loh
- Department of Pharmacology, Medical School University of Minnesota, Minneapolis, MN, 55455-0217, USA
| | - Shiu-Hwa Yeh
- Institute of Biotechnology and Pharmaceutical Research, National Health Research Institutes, Zhunan, 35053, Taiwan.
- The PhD Program for Neural Regenerative Medicine, Taipei Medical University, Taipei, 110, Taiwan.
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Liebick M, Henze S, Vogt V, Oppermann M. Functional consequences of chemically-induced β-arrestin binding to chemokine receptors CXCR4 and CCR5 in the absence of ligand stimulation. Cell Signal 2017; 38:201-211. [PMID: 28733085 DOI: 10.1016/j.cellsig.2017.07.010] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2017] [Revised: 06/26/2017] [Accepted: 07/15/2017] [Indexed: 01/14/2023]
Abstract
Chemokine receptor signaling is a tightly regulated process which was for a long time exclusively attributed to heterotrimeric G proteins. β-Arrestins constitute a separable signaling arm from classical heterotrimeric G proteins, in addition to their well-established roles in receptor desensitization and endocytosis. In order to clearly dissect β-arrestin- from G protein-dependent effects we forced the recruitment of β-arrestin to CXCR4 and CCR5 independently of agonist-promoted receptor activation through chemically-induced dimerization. Targeting β-arrestins to receptors at the plasma membrane prior to chemokine stimulation attenuated G protein-mediated calcium release. Association of β-arrestins to the receptors was sufficient to induce their internalization in the absence of ligand and this effect could be further enhanced by translocation of a constitutively active β-arrestin 1 variant. CXCR4 and CCR5 were targeted to different intracellular compartments upon chemical-induced dimerization with β-arrestins and reproduced the intracellular distribution of receptors after activation with their respective ligands. Our data further provide evidence for direct β-arrestin-mediated signaling via MAP kinases ERK 1/2. These results provide clear evidence that CXCR4- or CCR5-β-arrestin complexes induce receptor endocytosis and signaling in the absence of G protein coupling and ligand-induced conformational changes of the receptor.
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Affiliation(s)
- Marcel Liebick
- Department of Cellular and Molecular Immunology, University of Göttingen, Göttingen, Niedersachsen, Germany.
| | - Sarah Henze
- Department of Cellular and Molecular Immunology, University of Göttingen, Göttingen, Niedersachsen, Germany
| | - Viola Vogt
- Department of Cellular and Molecular Immunology, University of Göttingen, Göttingen, Niedersachsen, Germany
| | - Martin Oppermann
- Department of Cellular and Molecular Immunology, University of Göttingen, Göttingen, Niedersachsen, Germany
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16
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Yang KC, Stepanov V, Martinsson S, Ettrup A, Takano A, Knudsen GM, Halldin C, Farde L, Finnema SJ. Fenfluramine Reduces [11C]Cimbi-36 Binding to the 5-HT2A Receptor in the Nonhuman Primate Brain. Int J Neuropsychopharmacol 2017; 20:683-691. [PMID: 28911007 PMCID: PMC5581490 DOI: 10.1093/ijnp/pyx051] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/25/2017] [Accepted: 06/18/2017] [Indexed: 12/24/2022] Open
Abstract
BACKGROUND [11C]Cimbi-36 is a serotonin 2A receptor agonist positron emission tomography radioligand that has recently been examined in humans. The binding of agonist radioligand is expected to be more sensitive to endogenous neurotransmitter concentrations than antagonist radioligands. In the current study, we compared the effect of serotonin releaser fenfluramine on the binding of [11C]Cimbi-36, [11C]MDL 100907 (a serotonin 2A receptor antagonist radioligand), and [11C]AZ10419369 (a serotonin 1B receptor partial agonist radioligand with established serotonin sensitivity) in the monkey brain. METHODS Eighteen positron emission tomography measurements, 6 for each radioligand, were performed in 3 rhesus monkeys before or after administration of 5.0 mg/kg fenfluramine. Binding potential values were determined with the simplified reference tissue model using cerebellum as the reference region. RESULTS Fenfluramine significantly decreased [11C]Cimbi-36 (26-62%) and [11C]AZ10419369 (35-58%) binding potential values in most regions (P < 0.05). Fenfluramine-induced decreases in [11C]MDL 100907 binding potential were 8% to 30% and statistically significant in 3 regions. Decreases in [11C]Cimbi-36 binding potential were larger than for [11C]AZ10419369 in neocortical and limbic regions (~35%) but smaller in striatum and thalamus (~40%). Decreases in [11C]Cimbi-36 binding potential were 0.9 to 2.8 times larger than for [11C]MDL 100907, and the fraction of serotonin 2A receptor in the high-affinity state was estimated as 54% in the neocortex. CONCLUSIONS The serotonin sensitivity of serotonin 2A receptor agonist radioligand [11C]Cimbi-36 was higher than for antagonist radioligand [11C]MDL 100907. The serotonin sensitivity of [11C]Cimbi-36 was similar to [11C]AZ10419369, which is one of the most sensitive radioligands. [11C]Cimbi-36 is a promising radioligand to examine serotonin release in the primate brain.
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Affiliation(s)
- Kai-Chun Yang
- Karolinska Institutet and Stockholm County Council, Department of Clinical Neuroscience, Center for Psychiatric Research, Stockholm, Sweden (Drs Yang and Stepanov, Mr Martinsson, and Drs Takano, Halldin, Farde, and Finnema); Rigshospitalet, Center for Integrated Molecular Brain Imaging, Copenhagen, Denmark and University of Copenhagen, Faculty of Health and Medicine Sciences, Copenhagen, Denmark (Drs Ettrup and Knudsen); AstraZeneca, PET Science Center at Karolinska Institutet, Personalized Health Care and Biomarkers, Stockholm, Sweden (Dr Farde).,Correspondence: Kai-Chun Yang, MD, Karolinska Institutet and Stockholm County Council, Department of Clinical Neuroscience, Center for Psychiatric Research, Karolinska University Hospital, Building R5:02, SE-171 76 Stockholm, Sweden ()
| | - Vladimir Stepanov
- Karolinska Institutet and Stockholm County Council, Department of Clinical Neuroscience, Center for Psychiatric Research, Stockholm, Sweden (Drs Yang and Stepanov, Mr Martinsson, and Drs Takano, Halldin, Farde, and Finnema); Rigshospitalet, Center for Integrated Molecular Brain Imaging, Copenhagen, Denmark and University of Copenhagen, Faculty of Health and Medicine Sciences, Copenhagen, Denmark (Drs Ettrup and Knudsen); AstraZeneca, PET Science Center at Karolinska Institutet, Personalized Health Care and Biomarkers, Stockholm, Sweden (Dr Farde)
| | - Stefan Martinsson
- Karolinska Institutet and Stockholm County Council, Department of Clinical Neuroscience, Center for Psychiatric Research, Stockholm, Sweden (Drs Yang and Stepanov, Mr Martinsson, and Drs Takano, Halldin, Farde, and Finnema); Rigshospitalet, Center for Integrated Molecular Brain Imaging, Copenhagen, Denmark and University of Copenhagen, Faculty of Health and Medicine Sciences, Copenhagen, Denmark (Drs Ettrup and Knudsen); AstraZeneca, PET Science Center at Karolinska Institutet, Personalized Health Care and Biomarkers, Stockholm, Sweden (Dr Farde)
| | - Anders Ettrup
- Karolinska Institutet and Stockholm County Council, Department of Clinical Neuroscience, Center for Psychiatric Research, Stockholm, Sweden (Drs Yang and Stepanov, Mr Martinsson, and Drs Takano, Halldin, Farde, and Finnema); Rigshospitalet, Center for Integrated Molecular Brain Imaging, Copenhagen, Denmark and University of Copenhagen, Faculty of Health and Medicine Sciences, Copenhagen, Denmark (Drs Ettrup and Knudsen); AstraZeneca, PET Science Center at Karolinska Institutet, Personalized Health Care and Biomarkers, Stockholm, Sweden (Dr Farde)
| | - Akihiro Takano
- Karolinska Institutet and Stockholm County Council, Department of Clinical Neuroscience, Center for Psychiatric Research, Stockholm, Sweden (Drs Yang and Stepanov, Mr Martinsson, and Drs Takano, Halldin, Farde, and Finnema); Rigshospitalet, Center for Integrated Molecular Brain Imaging, Copenhagen, Denmark and University of Copenhagen, Faculty of Health and Medicine Sciences, Copenhagen, Denmark (Drs Ettrup and Knudsen); AstraZeneca, PET Science Center at Karolinska Institutet, Personalized Health Care and Biomarkers, Stockholm, Sweden (Dr Farde)
| | - Gitte M Knudsen
- Karolinska Institutet and Stockholm County Council, Department of Clinical Neuroscience, Center for Psychiatric Research, Stockholm, Sweden (Drs Yang and Stepanov, Mr Martinsson, and Drs Takano, Halldin, Farde, and Finnema); Rigshospitalet, Center for Integrated Molecular Brain Imaging, Copenhagen, Denmark and University of Copenhagen, Faculty of Health and Medicine Sciences, Copenhagen, Denmark (Drs Ettrup and Knudsen); AstraZeneca, PET Science Center at Karolinska Institutet, Personalized Health Care and Biomarkers, Stockholm, Sweden (Dr Farde)
| | - Christer Halldin
- Karolinska Institutet and Stockholm County Council, Department of Clinical Neuroscience, Center for Psychiatric Research, Stockholm, Sweden (Drs Yang and Stepanov, Mr Martinsson, and Drs Takano, Halldin, Farde, and Finnema); Rigshospitalet, Center for Integrated Molecular Brain Imaging, Copenhagen, Denmark and University of Copenhagen, Faculty of Health and Medicine Sciences, Copenhagen, Denmark (Drs Ettrup and Knudsen); AstraZeneca, PET Science Center at Karolinska Institutet, Personalized Health Care and Biomarkers, Stockholm, Sweden (Dr Farde)
| | - Lars Farde
- Karolinska Institutet and Stockholm County Council, Department of Clinical Neuroscience, Center for Psychiatric Research, Stockholm, Sweden (Drs Yang and Stepanov, Mr Martinsson, and Drs Takano, Halldin, Farde, and Finnema); Rigshospitalet, Center for Integrated Molecular Brain Imaging, Copenhagen, Denmark and University of Copenhagen, Faculty of Health and Medicine Sciences, Copenhagen, Denmark (Drs Ettrup and Knudsen); AstraZeneca, PET Science Center at Karolinska Institutet, Personalized Health Care and Biomarkers, Stockholm, Sweden (Dr Farde)
| | - Sjoerd J Finnema
- Karolinska Institutet and Stockholm County Council, Department of Clinical Neuroscience, Center for Psychiatric Research, Stockholm, Sweden (Drs Yang and Stepanov, Mr Martinsson, and Drs Takano, Halldin, Farde, and Finnema); Rigshospitalet, Center for Integrated Molecular Brain Imaging, Copenhagen, Denmark and University of Copenhagen, Faculty of Health and Medicine Sciences, Copenhagen, Denmark (Drs Ettrup and Knudsen); AstraZeneca, PET Science Center at Karolinska Institutet, Personalized Health Care and Biomarkers, Stockholm, Sweden (Dr Farde)
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Passoni I, Leonzino M, Gigliucci V, Chini B, Busnelli M. Carbetocin is a Functional Selective Gq Agonist That Does Not Promote Oxytocin Receptor Recycling After Inducing β-Arrestin-Independent Internalisation. J Neuroendocrinol 2016; 28. [PMID: 26751410 PMCID: PMC5021139 DOI: 10.1111/jne.12363] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/06/2015] [Revised: 12/30/2015] [Accepted: 01/07/2016] [Indexed: 01/08/2023]
Abstract
Carbetocin, a long-acting oxytocin analogue, has been reported to elicit interesting and peculiar behavioural effects. The present study investigated the molecular pharmacology of carbetocin, aiming to better understand the molecular basis of its action in the brain. Using bioluminescence resonance energy transfer biosensors, we characterised the effects of carbetocin on the three human oxytocin/vasopressin receptors expressed in the nervous system: the oxytocin receptor (OXTR) and the vasopressin V1a (V1aR) and V1b (V1bR) receptors. Our results indicate that (i) carbetocin activates the OXTR but not the V1aR and V1bR at which it may act as an antagonist; (ii) carbetocin selectively activates only the OXTR/Gq pathway displaying a strong functional selectivity; (iii) carbetocin is a partial agonist at the OXTR/Gq coupling; (iv) carbetocin promotes OXTR internalisation via a previously unreported β-arrestin-independent pathway; and (v) carbetocin does not induce OXTR recycling to the plasma membrane. Altogether, these molecular pharmacology features identify carbetocin as a substantially different analogue compared to the endogenous oxytocin and, consequently, carbetocin is not expected to mimic oxytocin in the brain. Whether these unique features of carbetocin could be exploited therapeutically remains to be established.
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Affiliation(s)
- I Passoni
- Department of Medical Biotechnology and Translational Medicine, Università degli Studi di Milano, Milan, Italy
| | - M Leonzino
- CNR, Institute of Neuroscience, Milan, Italy
| | - V Gigliucci
- CNR, Institute of Neuroscience, Milan, Italy
| | - B Chini
- CNR, Institute of Neuroscience, Milan, Italy
- Humanitas Clinical and Research Institute, Rozzano, Italy
| | - M Busnelli
- Department of Medical Biotechnology and Translational Medicine, Università degli Studi di Milano, Milan, Italy
- CNR, Institute of Neuroscience, Milan, Italy
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18
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Zhang G, Stackman RW. The role of serotonin 5-HT2A receptors in memory and cognition. Front Pharmacol 2015; 6:225. [PMID: 26500553 PMCID: PMC4594018 DOI: 10.3389/fphar.2015.00225] [Citation(s) in RCA: 178] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2015] [Accepted: 09/22/2015] [Indexed: 01/31/2023] Open
Abstract
Serotonin 5-HT2A receptors (5-HT2ARs) are widely distributed in the central nervous system, especially in brain region essential for learning and cognition. In addition to endogenous 5-HT, several hallucinogens, antipsychotics, and antidepressants function by targeting 5-HT2ARs. Preclinical studies show that 5-HT2AR antagonists have antipsychotic and antidepressant properties, whereas agonist ligands possess cognition-enhancing and hallucinogenic properties. Abnormal 5-HT2AR activity is associated with a number of psychiatric disorders and conditions, including depression, schizophrenia, and drug addiction. In addition to its traditional activity as a G protein-coupled receptor (GPCR), recent studies have defined novel operations of 5-HT2ARs. Here we review progress in the (1) receptor anatomy and biology: distribution, signaling, polymerization and allosteric modulation; and (2) receptor functions: learning and memory, hallucination and spatial cognition, and mental disorders. Based on the recent progress in basic research on the 5-HT2AR, it appears that post-training 5-HT2AR activation enhances non-spatial memory consolidation, while pre-training 5-HT2AR activation facilitates fear extinction. Further, the potential influence that 5-HT2AR-elicited visual hallucinations may have on visual cue (i.e., landmark) guided spatial cognition is discussed. We conclude that the development of selective 5-HT2AR modulators to target distinct signaling pathways and neural circuits represents a new possibility for treating emotional, neuropsychiatric, and neurodegenerative disorders.
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Affiliation(s)
- Gongliang Zhang
- College of Basic Medicine, Anhui Medical University Hefei, China ; Department of Biology, Charles E. Schmidt College of Science, Florida Atlantic University, Jupiter FL, USA ; Jupiter Life Science Initiative, Florida Atlantic University, Jupiter FL, USA
| | - Robert W Stackman
- Jupiter Life Science Initiative, Florida Atlantic University, Jupiter FL, USA ; Department of Psychology, Charles E. Schmidt College of Science, Florida Atlantic University, Jupiter FL, USA
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19
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White KL, Scopton AP, Rives ML, Bikbulatov RV, Polepally PR, Brown PJ, Kenakin T, Javitch JA, Zjawiony JK, Roth BL. Identification of novel functionally selective κ-opioid receptor scaffolds. Mol Pharmacol 2014; 85:83-90. [PMID: 24113749 PMCID: PMC3868907 DOI: 10.1124/mol.113.089649] [Citation(s) in RCA: 102] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2013] [Accepted: 10/10/2013] [Indexed: 11/22/2022] Open
Abstract
The κ-opioid receptor (KOR)-dynorphin system has been implicated in the control of affect, cognition, and motivation, and is thought to be dysregulated in mood and psychotic disorders, as well as in various phases of opioid dependence. KOR agonists exhibit analgesic effects, although the adverse effects produced by some KOR agonists, including sedation, dysphoria, and hallucinations, have limited their clinical use. Interestingly, KOR-mediated dysphoria, assessed in rodents as aversion, has recently been attributed to the activation of the p38 mitogen-activated protein kinase pathway following arrestin recruitment to the activated KOR. Therefore, KOR-selective G protein-biased agonists, which do not recruit arrestin, have been proposed to be more effective analgesics, without the adverse effects triggered by the arrestin pathway. As an initial step toward identifying novel biased KOR agonists, we applied a multifaceted screening strategy utilizing both in silico and parallel screening approaches. We identified several KOR-selective ligand scaffolds with a range of signaling bias in vitro. The arylacetamide-based scaffold includes both G protein- and β-arrestin-biased ligands, while the endogenous peptides and the diterpene scaffolds are G protein biased. Interestingly, we found scaffold screening to be more successful than library screening in identifying biased ligands. Many of the identified functionally selective ligands are potent selective KOR agonists that are reported to be active in the central nervous system. They therefore represent excellent candidates for in vivo studies aiming at determining the behavioral effects mediated by specific KOR-mediated signaling cascades.
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Affiliation(s)
- Kate L White
- Department of Pharmacology (K.L.W., T.K., B.L.R.) and National Institute of Mental Health Psychoactive Drug Screening Program (B.L.R.), University of North Carolina, Chapel Hill, North Carolina; Departments of Psychiatry (M.-L.R, J.A.J.) and Pharmacology (J.A.J.), Columbia University, College of Physicians and Surgeons, New York, New York; New York Division of Molecular Therapeutics, New York State Psychiatric Institute, New York, New York (M.-L.R., J.A.J.); Department of Pharmacognosy, University of Mississippi, University, Mississippi (R.V.B., P.R.P., J.K.Z.); and Structural Genomics Consortium, University of Toronto, Toronto, Ontario, Canada (A.P.S., P.J.B.)
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20
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Li RWS, Yang C, Kwan YW, Chan SW, Lee SMY, Leung GPH. Involvement of organic cation transporter-3 and plasma membrane monoamine transporter in serotonin uptake in human brain vascular smooth muscle cells. Front Pharmacol 2013; 4:14. [PMID: 23407616 PMCID: PMC3569667 DOI: 10.3389/fphar.2013.00014] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2012] [Accepted: 01/25/2013] [Indexed: 02/01/2023] Open
Abstract
The serotonin (5-HT) uptake system is supposed to play a crucial part in vascular functions by “fine-tuning” the local concentration of 5-HT in the vicinity of 5-HT2 receptors in vascular smooth muscle cells. In this study, the mechanism of 5-HT uptake in human brain vascular smooth muscle cells (HBVSMCs) was investigated. [3H]5-HT uptake in HBVSMCs was Na+-independent. Kinetic analyses of [3H]5-HT uptake in HBVSMCs revealed a Km of 50.36 ± 10.2 mM and a Vmax of 1033.61 ± 98.86 pmol/mg protein/min. The specific serotonin re-uptake transporter (SERT) inhibitor citalopram, the specific norepinephrine transporter (NET) inhibitor desipramine, and the dopamine transporter (DAT) inhibitor GBR12935 inhibited 5-HT uptake in HBVSMCs with IC50 values of 97.03 ± 40.10, 10.49 ± 5.98, and 2.80 ± 1.04 μM, respectively. These IC50 values were 100-fold higher than data reported by other authors, suggesting that those inhibitors were not blocking their corresponding transporters. Reverse transcription-polymerase chain reaction results demonstrated the presence of mRNA for organic cation transporter (OCT)-3 and plasma membrane monoamine transporter (PMAT), but the absence of OCT-1, OCT-2, SERT, NET, and DAT. siRNA knockdown of OCT-3 and PMAT specifically attenuated 5-HT uptake in HBVSMCs. It is concluded that 5-HT uptake in HBVSMCs was mediated predominantly by a low-affinity and Na+-independent mechanism. The most probable candidates are OCT-3 and PMAT, but not the SERT.
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Affiliation(s)
- Rachel W S Li
- Department of Pharmacology and Pharmacy, The University of Hong Kong Pokfulam, Hong Kong
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21
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Gupta K, Subramanian H, Klos A, Ali H. Phosphorylation of C3a receptor at multiple sites mediates desensitization, β-arrestin-2 recruitment and inhibition of NF-κB activity in mast cells. PLoS One 2012; 7:e46369. [PMID: 23077507 PMCID: PMC3471852 DOI: 10.1371/journal.pone.0046369] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2012] [Accepted: 08/29/2012] [Indexed: 01/21/2023] Open
Abstract
Background Phosphorylation of G protein coupled receptors (GPCRs) by G protein coupled receptor kinases (GRKs) and the subsequent recruitment of β-arrestins are important for their desensitization. Using shRNA-mediated gene silencing strategy, we have recently shown that GRK2, GRK3 and β-arrestin-2 promote C3a receptor (C3aR) desensitization in human mast cells. We also demonstrated that β-arrestin-2 provides an inhibitory signal for NF-κB activation. C3aR possesses ten potential phosphorylation sites within its carboxyl terminus but their role on desensitization, β-arrestin recruitment and NF-κB activation has not been determined. Methodology/Principal Findings We utilized a site directed mutagenesis approach in transfected HEK293 cells to determine the role of receptor phosphorylation on β-arrestin-2 recruitment and RBL-2H3 cells for functional studies. We found that although Ala substitution of Ser475/479, Thr480/481 residues resulted in 58±3.8% decrease in agonist-induced C3aR phosphorylation there was no change in β-arrestin-2 binding or receptor desensitization. By contrast, Ala substitution of Thr463, Ser465, Thr466 and Ser470 led to 40±1.3% decrease in agonist-induced receptor phosphorylation but this was associated with 74±2.4% decreases in β-arrestin-2 binding, significantly reduced desensitization and enhanced NF-κB activation. Combined mutation of these Ser/Thr residues along with Ser459 (mutant MT7), resulted in complete loss of receptor phosphorylation and β-arrestin-2 binding. RBL-2H3 cells expressing MT7 responded to C3a for greater Ca2+ mobilization, degranulation and NF-κB activation when compared to the wild-type receptor. Interestingly, co-expression of MT7 with a constitutively active mutant of β-arrestin (R169E) inhibited C3a-induced degranulation by 28±2.4% and blocked NF-κB activation by 80±2.4%. Conclusion/Significance This study demonstrates that although C3a causes phosphorylation of its receptor at multiple sites, Ser459, Thr463, Ser465, Thr466 and Ser470 participate in C3aR desensitization, β-arrestin-2 recruitment and inhibition of NF-κB activity. Furthermore, β-arrestin-2 inhibits C3a-induced NF-κB activation via receptor desensitization-dependent and independent pathways.
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Affiliation(s)
- Kshitij Gupta
- Department of Pathology, School of Dental Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Hariharan Subramanian
- Department of Pathology, School of Dental Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Andreas Klos
- Institute of Medical Microbiology and Hospital Epidemiology, Medical School Hannover, Hannover, Germany
| | - Hydar Ali
- Department of Pathology, School of Dental Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
- * E-mail:
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22
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Talbot PS, Slifstein M, Hwang DR, Huang Y, Scher E, Abi-Dargham A, Laruelle M. Extended characterisation of the serotonin 2A (5-HT2A) receptor-selective PET radiotracer 11C-MDL100907 in humans: quantitative analysis, test-retest reproducibility, and vulnerability to endogenous 5-HT tone. Neuroimage 2011; 59:271-85. [PMID: 21782029 DOI: 10.1016/j.neuroimage.2011.07.001] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2011] [Revised: 06/29/2011] [Accepted: 07/01/2011] [Indexed: 11/17/2022] Open
Abstract
INTRODUCTION Scanning properties and analytic methodology of the 5-HT2A receptor-selective positron emission tomography (PET) tracer 11C-MDL100907 have been partially characterised in previous reports. We present an extended characterisation in healthy human subjects. METHODS 64 11C-MDL100907 PET scans with metabolite-corrected arterial input function were performed in 39 healthy adults (18-55 years). 12 subjects were scanned twice (duration 150 min) to provide data on plasma analysis, model order estimation, and stability and test-retest characteristics of outcome measures. All other scans were 90 min duration. 3 subjects completed scanning at baseline and following 5-HT2A receptor antagonist medication (risperidone or ciproheptadine) to provide definitive data on the suitability of the cerebellum as reference region. 10 subjects were scanned under reduced 5-HT and control conditions using rapid tryptophan depletion to investigate vulnerability to competition with endogenous 5-HT. 13 subjects were scanned as controls in clinical protocols. Pooled data were used to analyse the relationship between tracer injected mass and receptor occupancy, and age-related decline in 5-HT2A receptors. RESULTS Optimum analytic method was a 2-tissue compartment model with arterial input function. However, basis function implementation of SRTM may be suitable for measuring between-group differences non-invasively and warrants further investigation. Scan duration of 90 min achieved stable outcome measures in all cortical regions except orbitofrontal which required 120 min. Binding potential (BPP and BPND) test-retest variability was very good (7-11%) in neocortical regions other than orbitofrontal, and moderately good (14-20%) in orbitofrontal cortex and medial temporal lobe. Saturation occupancy of 5-HT2A receptors by risperidone validates the use of the cerebellum as a region devoid of specific binding for the purposes of PET. We advocate a mass limit of 4.6 μg to remain below 5% receptor occupancy. 11C-MDL100907 specific binding is not vulnerable to competition with endogenous 5-HT in humans. Paradoxical decreases in BPND were found in right prefrontal cortex following reduced 5-HT, possibly representing receptor internalisation. Mean age-related decline in brain 5-HT2A receptors was 14.0±5.0% per decade, and higher in prefrontal regions. CONCLUSIONS Our data confirm and extend support for 11C-MDL100907 as a PET tracer with very favourable properties for quantifying 5-HT2A receptors in the human brain.
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Affiliation(s)
- Peter S Talbot
- Department of Psychiatry, Columbia University College of Physicians and Surgeons and the New York State Psychiatric Institute, New York, NY 10032, USA.
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Björk K, Svenningsson P. Modulation of monoamine receptors by adaptor proteins and lipid rafts: role in some effects of centrally acting drugs and therapeutic agents. Annu Rev Pharmacol Toxicol 2011; 51:211-42. [PMID: 20887195 DOI: 10.1146/annurev-pharmtox-010510-100520] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The monoamines and their cognate receptors are widespread in the central nervous system and are vital for normal brain function. Dysfunction in these systems underlies several psychiatric and neurological disease states, and consequently monoamines are targets of a host of pharmacotherapies. This review provides an overview on how monoamine receptors are regulated by adaptor proteins and lipid rafts with emphasis on interactions in nerve cells. Monoamine receptors have prominent intracellular loops that provide binding sites for adaptor proteins. Receptor function is further modulated by cholesterol and submembranous microdomains termed lipid rafts. These interactions determine several facets of G protein-coupled receptor (GPCR) function including trafficking, localization, and signaling. Possible roles of adaptor proteins and lipid rafts in disease states and in mediating actions of drugs and therapeutic agents are also discussed.
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Affiliation(s)
- Karl Björk
- Center for Molecular Medicine, Karolinska Institutet, Stockholm, Sweden
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24
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Baldys A, Raymond JR. Role of c-Cbl carboxyl terminus in serotonin 5-HT2A receptor recycling and resensitization. J Biol Chem 2011; 286:24656-65. [PMID: 21464131 DOI: 10.1074/jbc.m110.119891] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
The 5-hydroxytryptamine 2A receptor (5-HT(2A)R) undergoes constitutive and agonist-dependent internalization. Despite many advances in our understanding of G protein-coupled receptor trafficking, the exact mechanism of endocytic sorting of G protein-coupled receptors remains obscure. Recently, we have reported a novel finding documenting a global role for the ubiquitin ligase c-Cbl in regulating vesicular sorting of epidermal growth factor receptor (Baldys, A., Göoz, M., Morinelli, T. A., Lee, M. H., Raymond, J. R., Jr., Luttrell, L. M., and Raymond, J. R., Sr. (2009) Biochemistry 48, 1462-1473). Thus, we tested the hypothesis that c-Cbl might play a role in 5-HT(2A)R recycling. In this study, we demonstrated an association of 5-HT(2A)R with c-Cbl. Furthermore, down-regulation of c-Cbl by RNA interference blocked efficient recycling of 5-HT(2A)R to the plasma membrane. Immunofluorescence microscopy revealed that 5-HT(2A) receptors were trapped in early endosome antigen 1- and Rab11-positive sorting endosomes in cells overexpressing c-Cbl mutants lacking carboxyl termini. This inhibitory effect was associated with a relative decrease in association of c-Cbl truncation proteins with the 5-HT(2A)R, compared with that observed for the full-length c-Cbl fusion protein. Consistent with the delayed recycling, 5-HT(2A)R resensitization was greatly attenuated in the presence of c-Cbl mutants lacking carboxyl termini, as detected by changes in the cytosolic calcium. Taken together, these studies have led to the discovery that the C-terminal region of c-Cbl plays a crucial role in the temporal and spatial control of 5-HT(2A)R recycling.
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Affiliation(s)
- Aleksander Baldys
- Nephrology Division, Department of Medicine, Medical University of South Carolina, Ralph H. Johnson Veterans Affairs Medical Center, Charleston, South Carolina 29425, USA
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25
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Dalrymple MB, Jaeger WC, Eidne KA, Pfleger KDG. Temporal profiling of orexin receptor-arrestin-ubiquitin complexes reveals differences between receptor subtypes. J Biol Chem 2011; 286:16726-33. [PMID: 21378163 PMCID: PMC3089514 DOI: 10.1074/jbc.m111.223537] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Orexin G protein-coupled receptors (OxRs) and their cognate agonists have been implicated in a number of disorders since their recent discovery, ranging from narcolepsy to formation of addictive behavior. Bioluminescence resonance energy transfer assays of agonist-occupied OxRs provided evidence for a strong dose-dependent interaction with both trafficking proteins β-arrestin 1 and 2 that required unusually high agonist concentrations compared with inositol phosphate signaling. This appears to be reflected in functional differences in potency with respect to orexin A (OxA) and OxR2-dependent ERK1/2 phosphorylation after 90 min compared with 2 min, potentially consistent with β-arrestin-mediated versus G protein-mediated signaling, respectively. Furthermore, extended bioluminescence resonance energy transfer kinetic data monitoring OxA-dependent receptor-β-arrestin and β-arrestin-ubiquitin proximity suggested subtype-specific differences in receptor trafficking, with OxR2 activation resulting in more sustained receptor-β-arrestin-ubiquitin complex formation than elicited by OxR1 activation. Enzyme-linked immunosorbent assay (ELISA) data also revealed that OxR1 underwent significantly more rapid recycling compared with OxR2. Finally, we have observed sustained OxA-dependent ERK1/2 phosphorylation in the presence of OxR2 compared with OxR1. Although both OxR subtypes could be classified as class B receptors for β-arrestin usage based on the initial strength of interaction with both β-arrestins, our temporal profiling revealed tangible differences between OxR subtypes. Consequently, OxR1 appears to fit uneasily into the commonly used β-arrestin classification scheme. More importantly, it is hoped that this improved profiling capability, enabling the subtleties of protein complex formation, stability, and duration to be assessed in live cells, will help unlock the therapeutic potential of targeting these receptors.
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Affiliation(s)
- Matthew B Dalrymple
- Laboratory for Molecular Endocrinology-G Protein-Coupled Receptors, Western Australian Institute for Medical Research and Centre for Medical Research, University of Western Australia, Nedlands, Perth, Western Australia 6009, Australia
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26
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Kim SK, Li Y, Abrol R, Heo J, Goddard WA. Predicted structures and dynamics for agonists and antagonists bound to serotonin 5-HT2B and 5-HT2C receptors. J Chem Inf Model 2011; 51:420-33. [PMID: 21299232 DOI: 10.1021/ci100375b] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Subtype 2 serotonin (5-hydroxytryptamine, 5-HT) receptors are major drug targets for schizophrenia, feeding disorders, perception, depression, migraines, hypertension, anxiety, hallucinogens, and gastrointestinal dysfunctions. (1) We report here the predicted structure of 5-HT2B and 5-HT2C receptors bound to highly potent and selective 5-HT2B antagonist PRX-08066 3, (pKi: 30 nM), including the key binding residues [V103 (2.53), L132 (3.29), V190 (4.60), and L347 (6.58)] determining the selectivity of binding to 5-HT2B over 5-HT2A. We also report structures of the endogenous agonist (5-HT) and a HT2B selective antagonist 2 (1-methyl-1-1,6,7,8-tetrahydro-pyrrolo[2,3-g]quinoline-5-carboxylic acid pyridine-3-ylamide). We examine the dynamics for the agonist- and antagonist-bound HT2B receptors in explicit membrane and water finding dramatically different patterns of water migration into the NPxxY motif and the binding site that correlates with the stability of ionic locks in the D(E)RY region.
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Affiliation(s)
- Soo-Kyung Kim
- Materials and Process Simulation Center, California Institute of Technology, Pasadena, California 91125, USA
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27
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Roth BL. Irving Page Lecture: 5-HT(2A) serotonin receptor biology: interacting proteins, kinases and paradoxical regulation. Neuropharmacology 2011; 61:348-54. [PMID: 21288474 DOI: 10.1016/j.neuropharm.2011.01.012] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2010] [Revised: 11/28/2010] [Accepted: 01/10/2011] [Indexed: 01/04/2023]
Abstract
5-Hydroxytryptamine(2A) (5-HT(2A)) serotonin receptors are important pharmacological targets for a large number of central nervous system and peripheral serotonergic medications. In this review article I summarize work mainly from my lab regarding serotonin receptor anatomy, pharmacology, signaling and regulation. I highlight the role of serotonin receptor interacting proteins and the emerging paradigm of G-protein coupled receptor functional selectivity.
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Affiliation(s)
- Bryan L Roth
- Department of Pharmacology, Program in Neurosciences, Lineberger Cancer Center, NIMH Psychoactive Drug Screening Program, and Division of Medicinal Chemistry and Natural Products, Room 4072, Genetic Medicine Building, University of North Carolina Chapel Hill Medical School, Chapel Hill, NC 27514, USA.
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28
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Bohn LM, Schmid CL. Serotonin receptor signaling and regulation via β-arrestins. Crit Rev Biochem Mol Biol 2010; 45:555-66. [PMID: 20925600 DOI: 10.3109/10409238.2010.516741] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Serotonin receptors are the product of 15 distinct genes, 14 of which are G protein-coupled receptors. These receptors are expressed in a wide range of cell types, including distinct neuronal populations, and promote diverse functional responses in multiple organ systems. These receptors are important for mediating the in vivo effects of their cognate neurotransmitter, serotonin, as well as the endogenous tryptamines. In addition, the actions of many drugs are mediated, either directly or indirectly, through serotonin receptors, including antidepressants, antipsychotics, anxiolytics, sleep aids, migraine therapies, gastrointestinal therapeutics and hallucinogenic drugs. It is becoming increasingly evident that serotonin receptors can engage in differential signaling that is determined by the chemical nature of the ligand and that ligands that demonstrate a predilection for inducing a particular signaling cascade are considered to have "functional selectivity". The elucidation of the cellular signaling pathways that mediate the physiological responses to serotonin and other agonists is an active area of investigation and will be an onward-looking focal point for determining how to effectively and selectively promote beneficial serotonergic mimicry while avoiding unwanted clinical side effects. This review highlights the modulation of serotonin 2A, 2C, and four receptors by β-arrestins, which may represent a fulcrum for biasing receptor responsiveness in vivo.
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Affiliation(s)
- Laura M Bohn
- The Scripps Research Institute, Molecular Therapeutics & Neuroscience, Jupiter, FL, USA.
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29
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Bhattacharya A, Sankar S, Panicker MM. Differences in the C-terminus contribute to variations in trafficking between rat and human 5-HT2Areceptor isoforms: identification of a primate-specific tripeptide ASK motif that confers GRK-2 and β arrestin-2 interactions. J Neurochem 2010; 112:723-32. [DOI: 10.1111/j.1471-4159.2009.06493.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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30
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31
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Allen JA, Yadav PN, Roth BL. Insights into the regulation of 5-HT2A serotonin receptors by scaffolding proteins and kinases. Neuropharmacology 2008; 55:961-8. [PMID: 18640136 DOI: 10.1016/j.neuropharm.2008.06.048] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2008] [Revised: 06/19/2008] [Accepted: 06/20/2008] [Indexed: 11/29/2022]
Abstract
5-HT(2A) serotonin receptors are essential molecular targets for the actions of LSD-like hallucinogens and atypical antipsychotic drugs. 5-HT(2A) serotonin receptors also mediate a variety of physiological processes in peripheral and central nervous systems including platelet aggregation, smooth muscle contraction, and the modulation of mood and perception. Scaffolding proteins have emerged as important regulators of 5-HT(2A) receptors and our recent studies suggest multiple scaffolds exist for 5-HT(2A) receptors including PSD95, arrestin, and caveolin. In addition, a novel interaction has emerged between p90 ribosomal S6 kinase and 5-HT(2A) receptors which attenuates receptor signaling. This article reviews our recent studies and emphasizes the role of scaffolding proteins and kinases in the regulation of 5-HT(2A) trafficking, targeting and signaling.
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Affiliation(s)
- John A Allen
- Department of Pharmacology, University of North Carolina, School of Medicine, 8032 Burnett-Womack, CB #7365, Chapel Hill, NC 27599-7365, USA
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32
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Agonist-directed signaling of the serotonin 2A receptor depends on beta-arrestin-2 interactions in vivo. Proc Natl Acad Sci U S A 2008; 105:1079-84. [PMID: 18195357 DOI: 10.1073/pnas.0708862105] [Citation(s) in RCA: 164] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Visual and auditory hallucinations accompany certain neuropsychiatric disorders, such as schizophrenia, and they also can be induced by the use or abuse of certain drugs. The heptahelical serotonin 2A receptors (5-HT2ARs) are molecular targets for drug-induced hallucinations. However, the cellular mechanisms by which the 5-HT2AR mediates these effects are not well understood. Drugs acting at the 5-HT2AR can trigger diverse signaling pathways that may be directed by the chemical properties of the drug. beta-arrestins are intracellular proteins that bind to heptahelical receptors and represent a point where such divergences in ligand-directed functional signaling could occur. Here we compare the endogenous agonist, serotonin, to a synthetic 5-HT2AR hallucinogenic agonist, 2,5-dimethoxy-4-iodoamphetamine (DOI), in mice lacking beta-arrestin-2, as well as in cells lacking beta-arrestins. In mice, we find that serotonin induces a head twitch response by a beta-arrestin-2-dependent mechanism. However, DOI invokes the behavior independent of beta-arrestin-2. The two structurally distinct agonists elicit different signal transduction and trafficking patterns upon activation of 5-HT2AR, which hinge on the presence of beta-arrestins. Our study suggests that the 5-HT2AR-beta-arrestin interaction may be particularly important in receptor function in response to endogenous serotonin levels, which could have major implications in drug development for treating neuropsychiatric disorders such as depression and schizophrenia.
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33
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Janoshazi A, Deraet M, Callebert J, Setola V, Guenther S, Saubamea B, Manivet P, Launay JM, Maroteaux L. Modified Receptor Internalization upon Coexpression of 5-HT1BReceptor and 5-HT2BReceptors. Mol Pharmacol 2007; 71:1463-74. [PMID: 17325130 DOI: 10.1124/mol.106.032656] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Serotonin 5-HT(2B) receptors are often coexpressed with 5-HT(1B) receptors, and cross-talk between the two receptors has been reported in various cell types. However, many mechanistic details underlying 5-HT(1B) and 5-HT(2B) receptor cross-talk have not been elucidated. We hypothesized that 5-HT(2B) and 5-HT(1B) receptors each affect the others' signaling by modulating the others' trafficking. We thus examined the agonist stimulated internalization kinetics of fluorescent protein-tagged 5-HT(2B) and 5-HT(1B) receptors when expressed alone and upon coexpression in LMTK(-) murine fibroblasts. Time-lapse confocal microscopy and whole-cell radioligand binding analyses revealed that, when expressed alone, 5-HT(2B) and 5-HT(1B) receptors displayed distinct half-lives. Upon coexpression, serotonin-induced internalization of 5-HT(2B) receptors was accelerated 5-fold and was insensitive to a 5-HT(2B) receptor antagonist. In this context, 5-HT(2B) receptors did internalize in response to a 5-HT(1B) receptor agonist. In contrast, co-expression did not render 5-HT(1B) receptor internalization sensitive to a 5-HT(2B) receptor agonist. The altered internalization kinetics of both receptors upon coexpression was probably not due to direct interaction because only low levels of colocalization were observed. Antibody knockdown experiments revealed that internalization of 5-HT(1B) receptors (expressed alone) was entirely clathrin-independent and Caveolin1-dependent, whereas that of 5-HT(2B) receptors (expressed alone) was Caveolin1-independent and clathrin-dependent. Upon coexpression, serotonin-induced 5-HT(2B) receptor internalization became partially Caveolin1-dependent, and serotonin-induced 5-HT(1B) receptor internalization became entirely Caveolin1-independent in a protein kinase Cepsilon-dependent fashion. In conclusion, these data demonstrate that coexpression of 5-HT(1B) and 5-HT(2B) receptors influences the internalization pathways and kinetics of both receptors.
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Affiliation(s)
- Agnes Janoshazi
- Centre National de la Recherche Scientifique UMR7104, Illkirch, France
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34
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Gurevich VV, Gurevich EV. The structural basis of arrestin-mediated regulation of G-protein-coupled receptors. Pharmacol Ther 2006; 110:465-502. [PMID: 16460808 PMCID: PMC2562282 DOI: 10.1016/j.pharmthera.2005.09.008] [Citation(s) in RCA: 294] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2005] [Accepted: 09/22/2005] [Indexed: 12/23/2022]
Abstract
The 4 mammalian arrestins serve as almost universal regulators of the largest known family of signaling proteins, G-protein-coupled receptors (GPCRs). Arrestins terminate receptor interactions with G proteins, redirect the signaling to a variety of alternative pathways, and orchestrate receptor internalization and subsequent intracellular trafficking. The elucidation of the structural basis and fine molecular mechanisms of the arrestin-receptor interaction paved the way to the targeted manipulation of this interaction from both sides to produce very stable or extremely transient complexes that helped to understand the regulation of many biologically important processes initiated by active GPCRs. The elucidation of the structural basis of arrestin interactions with numerous non-receptor-binding partners is long overdue. It will allow the construction of fully functional arrestins in which the ability to interact with individual partners is specifically disrupted or enhanced by targeted mutagenesis. These "custom-designed" arrestin mutants will be valuable tools in defining the role of various interactions in the intricate interplay of multiple signaling pathways in the living cell. The identification of arrestin-binding sites for various signaling molecules will also set the stage for designing molecular tools for therapeutic intervention that may prove useful in numerous disorders associated with congenital or acquired disregulation of GPCR signaling.
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Affiliation(s)
- Vsevolod V Gurevich
- Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN 37232, USA.
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35
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Buznikov GA, Peterson RE, Nikitina LA, Bezuglov VV, Lauder JM. The Pre-nervous Serotonergic System of Developing Sea Urchin Embryos and Larvae: Pharmacologic and Immunocytochemical Evidence. Neurochem Res 2005; 30:825-37. [PMID: 16187217 DOI: 10.1007/s11064-005-6876-6] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/16/2005] [Indexed: 10/25/2022]
Abstract
Forty serotonin-related neurochemicals were tested on embryos and larvae of Lytechinus variegatus and other sea urchin species. Some of these substances (agonists of 5-HT1 receptors, antagonists of 5-HT2, 5-HT3 or 5-HT4 receptors, and inhibitors of the serotonin transporter, SERT) perturbed post-blastulation development, eliciting changes in embryonic/larval phenotypes typical for each class of receptor ligand. These developmental malformations were prevented completely or partially by serotonin (5-HT) or 5-HT analogs (5-HTQ, AA-5-HT), providing evidence for the putative localization of cellular targets. Immunoreactive 5-HT, 5-HT receptors and SERT were found in pre-nervous embryos and larvae of both L. variegatus and Strongylocentrotus droebachiensis. During gastrulation, these components of the serotonergic system were localized to the archenteron (primary gut), mesenchyme-like cells, and often the apical ectoderm. These results provide evidence that pre-nervous 5-HT may regulate early events of sea urchin embryogenesis, mediated by 5-HT receptors or the 5-HT transporter.
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Affiliation(s)
- Gennady A Buznikov
- Department of Cell and Developmental Biology, University of North Carolina School of Medicine, Chapel Hill, NC 27599-7090, USA.
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36
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Key TA, Vines CM, Wagener BM, Gurevich VV, Sklar LA, Prossnitz ER. Inhibition of chemoattractant N-formyl peptide receptor trafficking by active arrestins. Traffic 2005; 6:87-99. [PMID: 15634210 DOI: 10.1111/j.1600-0854.2004.00248.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Recent studies have highlighted the emergence of a class of G protein-coupled receptors that are internalized in an arrestin-independent manner. In addition to demonstrating that the N-formyl peptide receptor belongs in this family, we have recently shown that recycling of the receptor requires the presence of arrestins. To further elucidate mechanisms of arrestin-dependent regulation of G protein-coupled receptor processing, we examined the effects of altering the receptor-arrestin complex on ternary complex formation and cellular trafficking of the N-formyl peptide receptor by studying two active arrestin-2 mutants (truncated arrestin-2 [1-382], and arrestin-2 I386A, V387A, F388A). Complexes between the N-formyl peptide receptor and active arrestins exhibited higher affinity in vitro than the complex between the N-formyl peptide receptor and wild-type arrestin and furthermore were observed in vivo by colocalization studies using confocal microscopy. To assess the effects of these altered interactions on receptor trafficking, we demonstrated that active, but not wild-type, arrestin expression retards N-formyl peptide receptor internalization. Furthermore, expression of arrestin-2 I386A/V387A/F388A but not arrestin-2 [1-382] inhibited recycling of the N-formyl peptide receptor, reflecting an expanded role for arrestins in G protein-coupled receptor processing and trafficking. Whereas the extent of N-formyl peptide receptor phosphorylation had no effect on the inhibition of internalization, N-formyl peptide receptor recycling was restored when the receptor was only partially phosphorylated. These results indicate not only that a functional interaction between receptor and arrestin is required for recycling of certain G protein-coupled receptors, such as the N-formyl peptide receptor, but that the pattern of receptor phosphorylation further regulates this process.
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Affiliation(s)
- T Alexander Key
- Department of Cell Biology and Physiology, University of New Mexico Health Sciences Center, Albuquerque, NM 87131, USA
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37
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Barthet G, Gaven F, Framery B, Shinjo K, Nakamura T, Claeysen S, Bockaert J, Dumuis A. Uncoupling and endocytosis of 5-hydroxytryptamine 4 receptors. Distinct molecular events with different GRK2 requirements. J Biol Chem 2005; 280:27924-34. [PMID: 15919661 DOI: 10.1074/jbc.m502272200] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
The 5-hydroxytryptamine type 4 receptors (5-HT4Rs) are involved in memory, cognition, feeding, respiratory control, and gastrointestinal motility through activation of a G(s)/cAMP pathway. We have shown that 5-HT4R undergoes rapid and profound homologous uncoupling in neurons. However, no significant uncoupling was observed in COS-7 or HEK293 cells, which expressed either no or a weak concentration of GRK2, respectively. High expression of GRK2 in neurons is likely to be the reason for this difference because overexpression of GRK2 in COS-7 and HEK293 cells reproduced rapid and profound uncoupling of 5-HT4R. We have also shown, for the first time, that GRK2 requirements for uncoupling and endocytosis were very different. Indeed, beta-arrestin/dynamin-dependent endocytosis was observed in HEK293 cells without any need of GRK2 overexpression. In addition to this difference, uncoupling and beta-arrestin/dynamin-dependent endocytosis were mediated through distinct mechanisms. Neither uncoupling nor beta-arrestin/dynamin-dependent endocytosis required the serine and threonine residues localized within the specific C-terminal domains of the 5-HT4R splice variants. In contrast, a cluster of serines and threonines, common to all variants, was an absolute requirement for beta-arrestin/dynamin-dependent receptor endocytosis, but not for receptor uncoupling. Furthermore, beta-arrestin/dynamin-dependent endocytosis and uncoupling were dependent on and independent of GRK2 kinase activity, respectively. These results clearly demonstrate that the uncoupling and endocytosis of 5-HT4R require different GRK2 concentrations and involve distinct molecular events.
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MESH Headings
- Alternative Splicing
- Amino Acid Sequence
- Animals
- Arrestins/metabolism
- COS Cells
- Cell Line
- Culture Media, Serum-Free/pharmacology
- Cyclic AMP/metabolism
- Cyclic AMP-Dependent Protein Kinases/chemistry
- Cyclic AMP-Dependent Protein Kinases/physiology
- DNA, Complementary/metabolism
- Dose-Response Relationship, Drug
- Dynamins/metabolism
- Endocytosis
- Enzyme-Linked Immunosorbent Assay
- Genes, Dominant
- Humans
- Immunoblotting
- Mice
- Microscopy, Confocal
- Microscopy, Fluorescence
- Molecular Sequence Data
- Neurons/metabolism
- Plasmids/metabolism
- Protein Binding
- Protein Conformation
- Protein Structure, Tertiary
- RNA/chemistry
- RNA/metabolism
- RNA, Messenger/metabolism
- Receptors, Serotonin, 5-HT4/chemistry
- Reverse Transcriptase Polymerase Chain Reaction
- Serine/chemistry
- Threonine/chemistry
- Time Factors
- Transfection
- beta-Adrenergic Receptor Kinases
- beta-Arrestins
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38
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van Koppen CJ, Jakobs KH. Arrestin-Independent Internalization of G Protein-Coupled Receptors:
Fig. 1. Mol Pharmacol 2004; 66:365-7. [PMID: 15322226 DOI: 10.1124/mol.104.003822] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Affiliation(s)
- Chris J van Koppen
- Department of Molecular Pharmacology, N.V. Organon, PO Box 20, 5340 BH Oss, The Netherlands.
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39
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Bhatnagar A, Sheffler DJ, Kroeze WK, Compton-Toth B, Roth BL. Caveolin-1 Interacts with 5-HT2A Serotonin Receptors and Profoundly Modulates the Signaling of Selected Gαq-coupled Protein Receptors. J Biol Chem 2004; 279:34614-23. [PMID: 15190056 DOI: 10.1074/jbc.m404673200] [Citation(s) in RCA: 136] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
5-Hydroxytryptamine 2A (5-HT(2A)) serotonin receptors are important for a variety of functions including vascular smooth muscle contraction, platelet aggregation, and the modulation of perception, cognition, and emotion. In a search for 5-HT(2A) receptor-interacting proteins, we discovered that caveolin-1 (Cav-1), a scaffolding protein enriched in caveolae, complexes with 5-HT(2A) receptors in a number of cell types including C6 glioma cells, transfected HEK-293 cells, and rat brain synaptic membrane preparations. To address the functional significance of this interaction, we performed RNA interference-mediated knockdown of Cav-1 in C6 glioma cells, a cell type that endogenously expresses both 5-HT(2A) receptors and Cav-1. We discovered that the in vitro knockdown of Cav-1 in C6 glioma cells nearly abolished 5-HT(2A) receptor-mediated signal transduction as measured by calcium flux assays. RNA interference-mediated knockdown of Cav-1 also greatly attenuated endogenous Galpha(q)-coupled P2Y purinergic receptor-mediated signaling without altering the signaling of PAR-1 thrombin receptors. Cav-1 appeared to modulate 5-HT(2A) signaling by facilitating the interaction of 5-HT(2A) receptors with Galpha(q). These studies provide compelling evidence for a prominent role of Cav-1 in regulating the functional activity of not only 5-HT(2A) serotonin receptors but also selected Galpha(q)-coupled receptors.
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Affiliation(s)
- Anushree Bhatnagar
- Department of Biochemistry, Case Western Reserve University School of Medicine, 2109 Adelbert Road, Cleveland, OH 44106, USA
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40
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Affiliation(s)
- Wesley K Kroeze
- Departments of Biochemistry, Neurosciences and Psychiatry, NIMH Psychoactive Drug Screening Program, Case Western Reserve University, School of Medicine, Cleveland, OH 44106, USA
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41
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Chen CH, Paing MM, Trejo J. Termination of protease-activated receptor-1 signaling by beta-arrestins is independent of receptor phosphorylation. J Biol Chem 2003; 279:10020-31. [PMID: 14699102 DOI: 10.1074/jbc.m310590200] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Protease-activated receptor 1 (PAR1), a G protein-coupled receptor (GPCR) for thrombin, is the prototypic member of a family of protease-activated receptors. PAR1 is irreversibly proteolytically activated; thus, the magnitude and duration of thrombin cellular responses are determined primarily by mechanisms responsible for termination of receptor signaling. Both phosphorylation and beta-arrestins contribute to rapid desensitization of PAR1 signaling. However, the relative contribution of each of these pathways to the termination of PAR1 signaling is not known. Co-expression of PAR1 with beta-arrestin 1 (betaarr1) in COS-7 cells resulted in a marked inhibition of PAR1 signaling, whereas beta-arrestin 2 (betaarr2) was essentially inactive. Strikingly, signaling by a PAR1 cytoplasmic tail mutant defective in agonist-induced phosphorylation was also attenuated more effectively by betaarr1 compared with betaarr2. In contrast, both beta-arrestin isoforms were equally effective at desensitizing the substance P receptor, a classic reversibly activated GPCR. PAR1 coimmunoprecipitated betaarr1 in an agonist-dependent manner, whereas betaarr2 association was virtually undetectable. Remarkably, betaarr1 also interacted with phosphorylation defective PAR1 mutant, whereas betaarr2 did not. Moreover, constitutively active beta-arrestin mutants, betaarr1 R169E and betaarr2 R170E, that bind to activated receptor independent of phosphorylation failed to enhance either wild type or mutant PAR1 desensitization compared with normal versions of these proteins. In contrast, beta-arrestin mutants displayed enhanced activity at desensitizing the serotonin 5-hydroxytryptamine(2A) receptor. Taken together, these results suggest that, in addition to PAR1 cytoplasmic tail phosphorylation itself, beta-arrestin binding independent of phosphorylation promotes desensitization of PAR1 signaling. These findings reveal a new level of complexity in the regulation of protease-activated GPCR signaling.
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Affiliation(s)
- Chii-Heui Chen
- Department of Pharmacology, Cardiovascular Biology Center, Lineberger Comprehensive Cancer Center, School of Medicine, University of North Carolina, Chapel Hill 27599-7365, USA
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42
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Xia Z, Gray JA, Compton-Toth BA, Roth BL. A direct interaction of PSD-95 with 5-HT2A serotonin receptors regulates receptor trafficking and signal transduction. J Biol Chem 2003; 278:21901-8. [PMID: 12682061 DOI: 10.1074/jbc.m301905200] [Citation(s) in RCA: 130] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The serotonin (5-hydroxytryptamine) 2A receptor (5-HT2A) is an important G protein-coupled receptor (GPCR) that mediates the effects of hallucinogens and is the target of a number of commonly prescribed medications including atypical antipsychotics, antidepressants, and anxiolytics. The 5-HT2A receptor possesses a canonical Type I PDZ-binding domain (X-Ser/Thr-X-Phi) at the carboxyl terminus and has been predicted, but never demonstrated, to interact with PDZ domain-containing proteins. We discovered that PSD-95, a prototypic PDZ domain-containing protein, directly associates with the 5-HT2A receptor and regulates 5-HT2A receptor-mediated signaling and trafficking in HEK-293 cells. Co-immunoprecipitation studies revealed that the native 5-HT2A receptor, but not a mutant lacking the PDZ-binding domain, interacted directly with PSD-95. The association with PSD-95 enhanced 5-HT2A receptor-mediated signal transduction, a novel action of PSD-95 on GPCRs. The augmentation of 5-HT2A receptor signaling by PSD-95 was not accompanied by alteration in the kinetics of 5-HT2A receptor desensitization but was associated with the inhibition of agonist-induced 5-HT2A receptor internalization. Additional studies demonstrated that 5-HT2A receptor and PSD-95 were co-localized in clusters on the cell surface of HEK-293 cells. Taken together, the present work elucidates novel roles for PSD-95 in regulating the functional activity and intracellular trafficking of 5-HT2A receptors and possibly other GPCRs.
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Affiliation(s)
- Zongqi Xia
- Department of Biochemistry, Case Western Reserve University School of Medicine, 10900 Euclid Avenue, Cleveland, OH 44106, USA
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