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Abstract
The Sterling Research Group identified pravadoline as an aminoalkylindole (AAI) non-steroidal anti-inflammatory pain reliever. As drug design progressed, the ability of AAI analogs to block prostaglandin synthesis diminished, and antinociceptive activity was found to result from action at the CB1 cannabinoid receptor, a G-protein-coupled receptor (GPCR) abundant in the brain. Several laboratories applied computational chemistry methods to ultimately conclude that AAI and cannabinoid ligands could overlap within a common binding pocket but that WIN55212-2 primarily utilized steric interactions via aromatic stacking, whereas cannabinoid ligands required some electrostatic interactions, particularly involving the CB1 helix-3 lysine. The Huffman laboratory identified strategies to establish CB2 receptor selectivity among cannabimimetic indoles to avoid their CB1-related adverse effects, thereby stimulating preclinical studies to explore their use as anti-hyperalgesic and anti-allodynic pharmacotherapies. Some AAI analogs activate novel GPCRs referred to as "Alkyl Indole" receptors, and some AAI analogs act at the colchicine-binding site on microtubules. The AAI compounds having the greatest potency to interact with the CB1 receptor have found their way into the market as "Spice" or "K2". The sale of these alleged "herbal products" evades FDA consumer protections for proper labeling and safety as a medicine, as well as DEA scheduling as compounds having no currently accepted medical use and a high potential for abuse. The distribution to the public of potent alkyl indole synthetic cannabimimetic chemicals without regard for consumer safety contrasts with the adherence to regulatory requirements for demonstration of safety that are routinely observed by ethical pharmaceutical companies that market medicines.
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Affiliation(s)
- Allyn C. Howlett
- Department of Physiology and Pharmacology, Wake Forest School of Medicine, Winston-Salem, NC 27157, USA
| | - Brian F. Thomas
- Department of Analytical Sciences, The Cronos Group, Toronto, ON M5V 2H1, Canada;
| | - John W. Huffman
- Department of Chemistry, Clemson University, Clemson, SC 29634, USA;
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2
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Abstract
The CB1 cannabinoid receptor is a G-protein coupled receptor highly expressed throughout the central nervous system that is a promising target for the treatment of various disorders, including anxiety, pain, and neurodegeneration. Despite the wide therapeutic potential of CB1, the development of drug candidates is hindered by adverse effects, rapid tolerance development, and abuse potential. Ligands that produce biased signaling—the preferential activation of a signaling transducer in detriment of another—have been proposed as a strategy to dissociate therapeutic and adverse effects for a variety of G-protein coupled receptors. However, biased signaling at the CB1 receptor is poorly understood due to a lack of strongly biased agonists. Here, we review studies that have investigated the biased signaling profile of classical cannabinoid agonists and allosteric ligands, searching for a potential therapeutic advantage of CB1 biased signaling in different pathological states. Agonist and antagonist bound structures of CB1 and proposed mechanisms of action of biased allosteric modulators are used to discuss a putative molecular mechanism for CB1 receptor activation and biased signaling. Current studies suggest that allosteric binding sites on CB1 can be explored to yield biased ligands that favor or hinder conformational changes important for biased signaling.
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3
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Shim JY. Prediction of essential binding domains for the endocannabinoid N-arachidonoylethanolamine (AEA) in the brain cannabinoid CB1 receptor. PLoS One 2021; 16:e0229879. [PMID: 34181638 PMCID: PMC8238219 DOI: 10.1371/journal.pone.0229879] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2020] [Accepted: 05/28/2021] [Indexed: 11/18/2022] Open
Abstract
Δ9-tetrahydrocannabinol (Δ9-THC), the main active ingredient of Cannabis sativa (marijuana), interacts with the human brain cannabinoid (CB1) receptor and mimics pharmacological effects of endocannabinoids (eCBs) like N-arachidonylethanolamide (AEA). Due to its flexible nature of AEA structure with more than 15 rotatable bonds, establishing its binding mode to the CB1 receptor is elusive. The aim of the present study was to explore possible binding conformations of AEA within the binding pocket of the CB1 receptor confirmed in the recently available X-ray crystal structures of the CB1 receptor and predict essential AEA binding domains. We performed long time molecular dynamics (MD) simulations of plausible AEA docking poses until its receptor binding interactions became optimally established. Our simulation results revealed that AEA favors to bind to the hydrophobic channel (HC) of the CB1 receptor, suggesting that HC holds essential significance in AEA binding to the CB1 receptor. Our results also suggest that the Helix 2 (H2)/H3 region of the CB1 receptor is an AEA binding subsite privileged over the H7 region.
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Affiliation(s)
- Joong-Youn Shim
- Department of Physical Sciences, School of Arts and Sciences, Dalton State College, Dalton, Georgia, United States of America
- * E-mail:
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4
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Garai S, Leo LM, Szczesniak AM, Hurst DP, Schaffer PC, Zagzoog A, Black T, Deschamps JR, Miess E, Schulz S, Janero DR, Straiker A, Pertwee RG, Abood ME, Kelly MEM, Reggio PH, Laprairie RB, Thakur GA. Discovery of a Biased Allosteric Modulator for Cannabinoid 1 Receptor: Preclinical Anti-Glaucoma Efficacy. J Med Chem 2021; 64:8104-8126. [PMID: 33826336 DOI: 10.1021/acs.jmedchem.1c00040] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
We apply the magic methyl effect to improve the potency/efficacy of GAT211, the prototypic 2-phenylindole-based cannabinoid type-1 receptor (CB1R) agonist-positive allosteric modulator (ago-PAM). Introducing a methyl group at the α-position of nitro group generated two diastereomers, the greater potency and efficacy of erythro, (±)-9 vs threo, (±)-10 constitutes the first demonstration of diastereoselective CB1R-allosteric modulator interaction. Of the (±)-9 enantiomers, (-)-(S,R)-13 evidenced improved potency over GAT211 as a CB1R ago-PAM, whereas (+)-(R,S)-14 was a CB1R allosteric agonist biased toward G protein- vs β-arrestin1/2-dependent signaling. (-)-(S,R)-13 and (+)-(R,S)-14 were devoid of undesirable side effects (triad test), and (+)-(R,S)-14 reduced intraocular pressure with an unprecedentedly long duration of action in a murine glaucoma model. (-)-(S,R)-13 docked into both a CB1R extracellular PAM and intracellular allosteric-agonist site(s), whereas (+)-(R,S)-14 preferentially engaged only the latter. Exploiting G-protein biased CB1R-allosteric modulation can offer safer therapeutic candidates for glaucoma and, potentially, other diseases.
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Affiliation(s)
- Sumanta Garai
- Department of Pharmaceutical Sciences, Bouvé College of Health Sciences, Northeastern University, Boston, Massachusetts 02115, United States
| | - Luciana M Leo
- Center for Substance Abuse Research, Lewis Katz School of Medicine, Temple University, Philadelphia, Pennsylvania 19140, United States
| | - Anna-Maria Szczesniak
- Department of Pharmacology and Department of Ophthalmology and Visual Sciences, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada
| | - Dow P Hurst
- Center for Drug Discovery, University of North Carolina Greensboro, Greensboro, North Carolina 27402, United States
| | - Peter C Schaffer
- Department of Pharmaceutical Sciences, Bouvé College of Health Sciences, Northeastern University, Boston, Massachusetts 02115, United States
| | - Ayat Zagzoog
- College of Pharmacy and Nutrition, University of Saskatchewan, 104 Clinic Pl, Saskatoon, Saskatchewan S7N2Z4, Canada
| | - Tallan Black
- College of Pharmacy and Nutrition, University of Saskatchewan, 104 Clinic Pl, Saskatoon, Saskatchewan S7N2Z4, Canada
| | - Jeffrey R Deschamps
- Naval Research Laboratory, Code 6930, 4555 Overlook Avenue, Washington, District of Columbia 20375, United States
| | - Elke Miess
- Department of Pharmacology and Toxicology, Jena University Hospital-Friedrich Schiller University Jena, D-07747 Jena, Germany
| | - Stefan Schulz
- Department of Pharmacology and Toxicology, Jena University Hospital-Friedrich Schiller University Jena, D-07747 Jena, Germany
| | - David R Janero
- Department of Pharmaceutical Sciences, Bouvé College of Health Sciences, Northeastern University, Boston, Massachusetts 02115, United States
| | - Alex Straiker
- The Gill Center and the Department of Psychological & Brain Sciences, Indiana University, 1101 E. 10th St, Bloomington, Indiana 47405, United States
| | - Roger G Pertwee
- School of Medicine, Medical Sciences and Nutrition, Institute of Medical Sciences, University of Aberdeen, Aberdeen AB25 2ZD, Scotland, U.K
| | - Mary E Abood
- Center for Substance Abuse Research, Lewis Katz School of Medicine, Temple University, Philadelphia, Pennsylvania 19140, United States
| | - Melanie E M Kelly
- Department of Pharmacology and Department of Ophthalmology and Visual Sciences, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada
| | - Patricia H Reggio
- Center for Drug Discovery, University of North Carolina Greensboro, Greensboro, North Carolina 27402, United States
| | - Robert B Laprairie
- College of Pharmacy and Nutrition, University of Saskatchewan, 104 Clinic Pl, Saskatoon, Saskatchewan S7N2Z4, Canada
- Department of Pharmacology and Department of Ophthalmology and Visual Sciences, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada
| | - Ganesh A Thakur
- Department of Pharmaceutical Sciences, Bouvé College of Health Sciences, Northeastern University, Boston, Massachusetts 02115, United States
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5
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Martin LJ, Banister SD, Bowen MT. Understanding the complex pharmacology of cannabidiol: Mounting evidence suggests a common binding site with cholesterol. Pharmacol Res 2021; 166:105508. [PMID: 33610721 DOI: 10.1016/j.phrs.2021.105508] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/11/2020] [Revised: 01/28/2021] [Accepted: 02/16/2021] [Indexed: 12/19/2022]
Abstract
Cannabidiol is claimed to bind to a large number of protein targets based on in vitro assays. This suggests opportunities for a wide range of therapeutic applications. On the other hand, the existence of phytochemical 'nuisance compounds' suggests some measure of caution - these compounds are capable of altering membrane biophysical properties and changing protein function without directly contacting a binding site. Like cannabidiol, cholesterol alters membrane properties, but it also binds directly to membrane proteins through abundant cholesterol recognition sites. We present the evidence that cannabidiol and cholesterol may bind to the same site on some proteins. As a starting point for further research, we also used blind docking to show that cannabidiol binds to a cholesterol binding site on the CB1 receptor. Elucidation of the mechanism(s) of action of cannabidiol will assist the prioritisation of in vitro hits across targets, improve the success rate of medicinal chemistry campaigns, and ultimately benefit patient populations by focusing resources on programs with the most translational potential.
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Affiliation(s)
- Lewis J Martin
- The University of Sydney, Brain and Mind Centre, The Lambert Initiative for Cannabinoid Therapeutics, Sydney, NSW, Australia; The University of Sydney, Brain and Mind Centre, Sydney, NSW, Australia; The University of Sydney, Faculty of Science, School of Psychology, NSW, Australia
| | - Samuel D Banister
- The University of Sydney, Brain and Mind Centre, The Lambert Initiative for Cannabinoid Therapeutics, Sydney, NSW, Australia; The University of Sydney, Brain and Mind Centre, Sydney, NSW, Australia
| | - Michael T Bowen
- The University of Sydney, Brain and Mind Centre, The Lambert Initiative for Cannabinoid Therapeutics, Sydney, NSW, Australia; The University of Sydney, Brain and Mind Centre, Sydney, NSW, Australia; The University of Sydney, Faculty of Science, School of Psychology, NSW, Australia.
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6
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Walsh KB, Andersen HK. Molecular Pharmacology of Synthetic Cannabinoids: Delineating CB1 Receptor-Mediated Cell Signaling. Int J Mol Sci 2020; 21:E6115. [PMID: 32854313 PMCID: PMC7503917 DOI: 10.3390/ijms21176115] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Revised: 08/12/2020] [Accepted: 08/14/2020] [Indexed: 12/17/2022] Open
Abstract
Synthetic cannabinoids (SCs) are a class of new psychoactive substances (NPSs) that exhibit high affinity binding to the cannabinoid CB1 and CB2 receptors and display a pharmacological profile similar to the phytocannabinoid (-)-trans-Δ9-tetrahydrocannabinol (THC). SCs are marketed under brand names such as K2 and Spice and are popular drugs of abuse among male teenagers and young adults. Since their introduction in the early 2000s, SCs have grown in number and evolved in structural diversity to evade forensic detection and drug scheduling. In addition to their desirable euphoric and antinociceptive effects, SCs can cause severe toxicity including seizures, respiratory depression, cardiac arrhythmias, stroke and psychosis. Binding of SCs to the CB1 receptor, expressed in the central and peripheral nervous systems, stimulates pertussis toxin-sensitive G proteins (Gi/Go) resulting in the inhibition of adenylyl cyclase, a decreased opening of N-type Ca2+ channels and the activation of G protein-gated inward rectifier (GIRK) channels. This combination of signaling effects dampens neuronal activity in both CNS excitatory and inhibitory pathways by decreasing action potential formation and neurotransmitter release. Despite this knowledge, the relationship between the chemical structure of the SCs and their CB1 receptor-mediated molecular actions is not well understood. In addition, the potency and efficacy of newer SC structural groups has not been determined. To address these limitations, various cell-based assay technologies are being utilized to develop structure versus activity relationships (SAR) for the SCs and to explore the effects of these compounds on noncannabinoid receptor targets. This review focuses on describing and evaluating these assays and summarizes our current knowledge of SC molecular pharmacology.
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Affiliation(s)
- Kenneth B. Walsh
- Department of Pharmacology, Physiology & Neuroscience, University of South Carolina, School of Medicine, Columbia, SC 29208, USA;
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7
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Linciano P, Citti C, Luongo L, Belardo C, Maione S, Vandelli MA, Forni F, Gigli G, Laganà A, Montone CM, Cannazza G. Isolation of a High-Affinity Cannabinoid for the Human CB1 Receptor from a Medicinal Cannabis sativa Variety: Δ 9-Tetrahydrocannabutol, the Butyl Homologue of Δ 9-Tetrahydrocannabinol. J Nat Prod 2020; 83:88-98. [PMID: 31891265 DOI: 10.1021/acs.jnatprod.9b00876] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The butyl homologues of Δ9-tetrahydrocannabinol, Δ9-tetrahydrocannabutol (Δ9-THCB), and cannabidiol, cannabidibutol (CBDB), were isolated from a medicinal Cannabis sativa variety (FM2) inflorescence. Appropriate spectroscopic and spectrometric characterization, including NMR, UV, IR, ECD, and HRMS, was carried out on both cannabinoids. The chemical structures and absolute configurations of the isolated cannabinoids were confirmed by comparison with the spectroscopic data of the respective compounds obtained by stereoselective synthesis. The butyl homologue of Δ9-THC, Δ9-THCB, showed an affinity for the human CB1 (Ki = 15 nM) and CB2 receptors (Ki = 51 nM) comparable to that of (-)-trans-Δ9-THC. Docking studies suggested the key bonds responsible for THC-like binding affinity for the CB1 receptor. The formalin test in vivo was performed on Δ9-THCB in order to reveal possible analgesic and anti-inflammatory properties. The tetrad test in mice showed a partial agonistic activity of Δ9-THCB toward the CB1 receptor.
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MESH Headings
- Analgesics/pharmacology
- Animals
- Cannabidiol/chemistry
- Cannabinoids/chemistry
- Cannabinoids/isolation & purification
- Cannabis/chemistry
- Dronabinol/chemistry
- Dronabinol/isolation & purification
- Humans
- Medical Marijuana
- Mice
- Molecular Structure
- Receptor, Cannabinoid, CB1/chemistry
- Receptor, Cannabinoid, CB1/isolation & purification
- Receptor, Cannabinoid, CB1/metabolism
- Receptor, Cannabinoid, CB2/chemistry
- Receptor, Cannabinoid, CB2/metabolism
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Affiliation(s)
- Pasquale Linciano
- Department of Life Sciences , University of Modena and Reggio Emilia , Via Campi 103 , 41125 Modena , Italy
| | - Cinzia Citti
- Department of Life Sciences , University of Modena and Reggio Emilia , Via Campi 103 , 41125 Modena , Italy
- Mediteknology s.r.l. , Via Arnesano , 73100 Lecce , Italy
- CNR NANOTEC , Campus Ecotekne, Via Monteroni , 73100 Lecce , Italy
| | - Livio Luongo
- Department of Experimental Medicine, Division of Pharmacology , Università della Campania "L. Vanvitelli" , Via Santa Maria di Costantinopoli 16 , 80138 Naples , Italy
| | - Carmela Belardo
- Department of Experimental Medicine, Division of Pharmacology , Università della Campania "L. Vanvitelli" , Via Santa Maria di Costantinopoli 16 , 80138 Naples , Italy
| | - Sabatino Maione
- Department of Experimental Medicine, Division of Pharmacology , Università della Campania "L. Vanvitelli" , Via Santa Maria di Costantinopoli 16 , 80138 Naples , Italy
| | - Maria Angela Vandelli
- Department of Life Sciences , University of Modena and Reggio Emilia , Via Campi 103 , 41125 Modena , Italy
| | - Flavio Forni
- Department of Life Sciences , University of Modena and Reggio Emilia , Via Campi 103 , 41125 Modena , Italy
| | - Giuseppe Gigli
- CNR NANOTEC , Campus Ecotekne, Via Monteroni , 73100 Lecce , Italy
| | - Aldo Laganà
- CNR NANOTEC , Campus Ecotekne, Via Monteroni , 73100 Lecce , Italy
- Department of Chemistry , Sapienza University of Rome , Piazzale Aldo Moro 5 , 00185 Rome , Italy
| | - Carmela Maria Montone
- Department of Chemistry , Sapienza University of Rome , Piazzale Aldo Moro 5 , 00185 Rome , Italy
| | - Giuseppe Cannazza
- Department of Life Sciences , University of Modena and Reggio Emilia , Via Campi 103 , 41125 Modena , Italy
- CNR NANOTEC , Campus Ecotekne, Via Monteroni , 73100 Lecce , Italy
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8
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Thapa D, Cairns EA, Szczesniak AM, Kulkarni PM, Straiker AJ, Thakur GA, Kelly MEM. Allosteric Cannabinoid Receptor 1 (CB1) Ligands Reduce Ocular Pain and Inflammation. Molecules 2020; 25:E417. [PMID: 31968549 PMCID: PMC7024337 DOI: 10.3390/molecules25020417] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2019] [Accepted: 01/16/2020] [Indexed: 01/08/2023] Open
Abstract
Cannabinoid receptor 1 (CB1) activation has been reported to reduce transient receptor potential cation channel subfamily V member 1 (TRPV1)-induced inflammatory responses and is anti-nociceptive and anti-inflammatory in corneal injury. We examined whether allosteric ligands, can modulate CB1 signaling to reduce pain and inflammation in corneal hyperalgesia. Corneal hyperalgesia was generated by chemical cauterization of cornea in wildtype and CB2 knockout (CB2-/-) mice. The novel racemic CB1 allosteric ligand GAT211 and its enantiomers GAT228 and GAT229 were examined alone or in combination with the orthosteric CB1 agonist Δ8-tetrahydrocannabinol (Δ8-THC). Pain responses were assessed following capsaicin (1 µM) stimulation of injured corneas at 6 h post-cauterization. Corneal neutrophil infiltration was also analyzed. GAT228, but not GAT229 or GAT211, reduced pain scores in response to capsaicin stimulation. Combination treatments of 0.5% GAT229 or 1% GAT211 with subthreshold Δ8-THC (0.4%) significantly reduced pain scores following capsaicin stimulation. The anti-nociceptive effects of both GAT229 and GAT228 were blocked with CB1 antagonist AM251, but remained unaffected in CB2-/- mice. Two percent GAT228, or the combination of 0.2% Δ8-THC with 0.5% GAT229 also significantly reduced corneal inflammation. CB1 allosteric ligands could offer a novel approach for treating corneal pain and inflammation.
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Affiliation(s)
- Dinesh Thapa
- Department of Pharmacology, Dalhousie University, Halifax, NS B3H 4R2, Canada
| | - Elizabeth A. Cairns
- Department of Pharmacology, Dalhousie University, Halifax, NS B3H 4R2, Canada
| | | | - Pushkar M. Kulkarni
- Department of Pharmaceutical Sciences, Northeastern University, Boston, MA 02115, USA
| | - Alex J. Straiker
- Department of Psychological and Brain Sciences, Indiana University, Bloomington, IN 47405, USA
| | - Ganesh A. Thakur
- Department of Pharmaceutical Sciences, Northeastern University, Boston, MA 02115, USA
| | - Melanie E. M. Kelly
- Department of Pharmacology, Dalhousie University, Halifax, NS B3H 4R2, Canada
- Department of Anesthesia, Pain Management & Perioperative Medicine, Dalhousie University, Halifax, NS B3H 4R2, Canada
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9
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Citti C, Linciano P, Russo F, Luongo L, Iannotta M, Maione S, Laganà A, Capriotti AL, Forni F, Vandelli MA, Gigli G, Cannazza G. A novel phytocannabinoid isolated from Cannabis sativa L. with an in vivo cannabimimetic activity higher than Δ 9-tetrahydrocannabinol: Δ 9-Tetrahydrocannabiphorol. Sci Rep 2019; 9:20335. [PMID: 31889124 PMCID: PMC6937300 DOI: 10.1038/s41598-019-56785-1] [Citation(s) in RCA: 102] [Impact Index Per Article: 20.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2019] [Accepted: 11/29/2019] [Indexed: 12/14/2022] Open
Abstract
(-)-Trans-Δ9-tetrahydrocannabinol (Δ9-THC) is the main compound responsible for the intoxicant activity of Cannabis sativa L. The length of the side alkyl chain influences the biological activity of this cannabinoid. In particular, synthetic analogues of Δ9-THC with a longer side chain have shown cannabimimetic properties far higher than Δ9-THC itself. In the attempt to define the phytocannabinoids profile that characterizes a medicinal cannabis variety, a new phytocannabinoid with the same structure of Δ9-THC but with a seven-term alkyl side chain was identified. The natural compound was isolated and fully characterized and its stereochemical configuration was assigned by match with the same compound obtained by a stereoselective synthesis. This new phytocannabinoid has been called (-)-trans-Δ9-tetrahydrocannabiphorol (Δ9-THCP). Along with Δ9-THCP, the corresponding cannabidiol (CBD) homolog with seven-term side alkyl chain (CBDP) was also isolated and unambiguously identified by match with its synthetic counterpart. The binding activity of Δ9-THCP against human CB1 receptor in vitro (Ki = 1.2 nM) resulted similar to that of CP55940 (Ki = 0.9 nM), a potent full CB1 agonist. In the cannabinoid tetrad pharmacological test, Δ9-THCP induced hypomotility, analgesia, catalepsy and decreased rectal temperature indicating a THC-like cannabimimetic activity. The presence of this new phytocannabinoid could account for the pharmacological properties of some cannabis varieties difficult to explain by the presence of the sole Δ9-THC.
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Affiliation(s)
- Cinzia Citti
- Mediteknology spin-off company of the National Council of Research (CNR), Via Arnesano, 73100, Lecce, Italy
- Institute of Nanotechnology of the National Council of Research (CNR NANOTEC), Via Monteroni, 73100, Lecce, Italy
- Department of Life Sciences, University of Modena and Reggio Emilia, Via Campi 103, 41125, Modena, Italy
| | - Pasquale Linciano
- Department of Life Sciences, University of Modena and Reggio Emilia, Via Campi 103, 41125, Modena, Italy
| | - Fabiana Russo
- Department of Life Sciences, University of Modena and Reggio Emilia, Via Campi 103, 41125, Modena, Italy
| | - Livio Luongo
- Department of Experimental Medicine, Division of Pharmacology, Università della Campania "L. Vanvitelli", Via Santa Maria di Costantinopoli 16, 80138, Naples, Italy
| | - Monica Iannotta
- Department of Experimental Medicine, Division of Pharmacology, Università della Campania "L. Vanvitelli", Via Santa Maria di Costantinopoli 16, 80138, Naples, Italy
| | - Sabatino Maione
- Department of Experimental Medicine, Division of Pharmacology, Università della Campania "L. Vanvitelli", Via Santa Maria di Costantinopoli 16, 80138, Naples, Italy
| | - Aldo Laganà
- Institute of Nanotechnology of the National Council of Research (CNR NANOTEC), Via Monteroni, 73100, Lecce, Italy
- Department of Chemistry, Sapienza University of Rome, Piazzale Aldo Moro 5, 00185, Rome, Italy
| | - Anna Laura Capriotti
- Department of Chemistry, Sapienza University of Rome, Piazzale Aldo Moro 5, 00185, Rome, Italy
| | - Flavio Forni
- Department of Life Sciences, University of Modena and Reggio Emilia, Via Campi 103, 41125, Modena, Italy
| | - Maria Angela Vandelli
- Department of Life Sciences, University of Modena and Reggio Emilia, Via Campi 103, 41125, Modena, Italy
| | - Giuseppe Gigli
- Institute of Nanotechnology of the National Council of Research (CNR NANOTEC), Via Monteroni, 73100, Lecce, Italy
| | - Giuseppe Cannazza
- Institute of Nanotechnology of the National Council of Research (CNR NANOTEC), Via Monteroni, 73100, Lecce, Italy.
- Department of Life Sciences, University of Modena and Reggio Emilia, Via Campi 103, 41125, Modena, Italy.
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10
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Alapafuja SO, Nikas SP, Ho TC, Tong F, Benchama O, Makriyannis A. Chain Substituted Cannabilactones with Selectivity for the CB2 Cannabinoid Receptor. Molecules 2019; 24:E3559. [PMID: 31581433 PMCID: PMC6804212 DOI: 10.3390/molecules24193559] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2019] [Revised: 09/25/2019] [Accepted: 09/27/2019] [Indexed: 11/21/2022] Open
Abstract
In earlier work, we reported a novel class of CB2 selective ligands namely cannabilactones. These compounds carry a dimethylheptyl substituent at C3, which is typical for synthetic cannabinoids. In the current study with the focus on the pharmacophoric side chain at C3 we explored the effect of replacing the C1'-gem-dimethyl group with the bulkier cyclopentyl ring, and, we also probed the chain's length and terminal carbon substitution with bromo or cyano groups. One of the analogs synthesized namely 6-[1-(1,9-dihydroxy-6-oxo-6H-benzo[c]chromen-3-yl) cyclopentyl] hexanenitrile (AM4346) has very high affinity (Ki = 4.9 nM) for the mouse CB2 receptor (mCB2) and 131-fold selectivity for that target over the rat CB1 (rCB1). The species difference in the affinities of AM4346 between the mouse (m) and the human (h) CB2 receptors is reduced when compared to our first-generation cannabilactones. In the cyclase assay, our lead compound was found to be a highly potent and efficacious hCB2 receptor agonist (EC50 = 3.7 ± 1.5 nM, E(max) = 89%). We have also extended our structure-activity relationship (SAR) studies to include biphenyl synthetic intermediates that mimic the structure of the phytocannabinoid cannabinodiol.
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Affiliation(s)
- Shakiru O Alapafuja
- Center for Drug Discovery and Department of Pharmaceutical Sciences, Northeastern University, Boston, MA 02115, USA.
| | - Spyros P Nikas
- Center for Drug Discovery and Department of Pharmaceutical Sciences, Northeastern University, Boston, MA 02115, USA.
| | - Thanh C Ho
- Center for Drug Discovery and Department of Pharmaceutical Sciences, Northeastern University, Boston, MA 02115, USA.
| | - Fei Tong
- Center for Drug Discovery and Department of Pharmaceutical Sciences, Northeastern University, Boston, MA 02115, USA.
| | - Othman Benchama
- Center for Drug Discovery and Department of Pharmaceutical Sciences, Northeastern University, Boston, MA 02115, USA.
| | - Alexandros Makriyannis
- Center for Drug Discovery and Department of Pharmaceutical Sciences, Northeastern University, Boston, MA 02115, USA.
- Department of Chemistry & Chemical Biology, Northeastern University, Boston, MA 02115, USA.
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11
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Abstract
The endocannabinoid system has emerged as a promising target for the treatment of numerous diseases, including cancer, neurodegenerative disorders, and metabolic syndromes. Thus far, two cannabinoid receptors, CB1 and CB2, have been discovered, which are found predominantly in the central nervous system (CB1) or the immune system (CB2), among other organs and tissues. CB1 receptor ligands have been shown to induce a complex pattern of intracellular effects. The binding of a ligand induces distinct conformational changes in the receptor, which will eventually translate into distinct intracellular signaling pathways through coupling to specific intracellular effector proteins. These proteins can mediate receptor desensitization, trafficking, or signaling. Ligand specificity and selectivity, complex cellular components, and the concomitant expression of other proteins (which either regulate the CB1 receptor or are regulated by the CB1 receptor) will affect the therapeutic outcome of its targeting. With an increased interest in G protein-coupled receptors (GPCR) research, in-depth studies using mutations, biological assays, and spectroscopic techniques (such as NMR, EPR, MS, FRET, and X-ray crystallography), as well as computational modelling, have begun to reveal a set of concerted structural features in Class A GPCRs which relate to signaling pathways and the mechanisms of ligand-induced activation, deactivation, or activity modulation. This review will focus on the structural features of the CB1 receptor, mutations known to bias its signaling, and reported studies of CB1 receptor ligands to control its specific signaling.
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Affiliation(s)
- Rufaida Al-Zoubi
- Department of Medicinal Chemistry and Pharmacognosy, Faculty of Pharmacy, Jordan University of Science & Technology, P.O.BOX 3030, Irbid 22110, Jordan.
| | - Paula Morales
- Departamento de Química-Física Biológica, Instituto de Química Física Rocasolano (IQFR-CSIC), Serrano 119, 28006 Madrid, Spain.
| | - Patricia H Reggio
- Chemistry and Biochemistry Department, UNC Greensboro, Greensboro, NC 27412, USA.
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12
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Floresta G, Apirakkan O, Rescifina A, Abbate V. Discovery of High-Affinity Cannabinoid Receptors Ligands through a 3D-QSAR Ushered by Scaffold-Hopping Analysis. Molecules 2018; 23:molecules23092183. [PMID: 30200181 PMCID: PMC6225167 DOI: 10.3390/molecules23092183] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2018] [Revised: 08/26/2018] [Accepted: 08/28/2018] [Indexed: 01/08/2023] Open
Abstract
Two 3D quantitative structure–activity relationships (3D-QSAR) models for predicting Cannabinoid receptor 1 and 2 (CB1 and CB2) ligands have been produced by way of creating a practical tool for the drug-design and optimization of CB1 and CB2 ligands. A set of 312 molecules have been used to build the model for the CB1 receptor, and a set of 187 molecules for the CB2 receptor. All of the molecules were recovered from the literature among those possessing measured Ki values, and Forge was used as software. The present model shows high and robust predictive potential, confirmed by the quality of the statistical analysis, and an adequate descriptive capability. A visual understanding of the hydrophobic, electrostatic, and shaping features highlighting the principal interactions for the CB1 and CB2 ligands was achieved with the construction of 3D maps. The predictive capabilities of the model were then used for a scaffold-hopping study of two selected compounds, with the generation of a library of new compounds with high affinity for the two receptors. Herein, we report two new 3D-QSAR models that comprehend a large number of chemically different CB1 and CB2 ligands and well account for the individual ligand affinities. These features will facilitate the recognition of new potent and selective molecules for CB1 and CB2 receptors.
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MESH Headings
- Cannabinoid Receptor Agonists/chemistry
- Cannabinoid Receptor Agonists/metabolism
- Cannabinoid Receptor Antagonists/chemistry
- Cannabinoid Receptor Antagonists/metabolism
- Drug Design
- Hydrophobic and Hydrophilic Interactions
- Ligands
- Models, Molecular
- Molecular Conformation
- Molecular Docking Simulation
- Molecular Dynamics Simulation
- Molecular Structure
- Protein Binding
- Quantitative Structure-Activity Relationship
- Receptor, Cannabinoid, CB1/chemistry
- Receptor, Cannabinoid, CB1/metabolism
- Receptor, Cannabinoid, CB2/chemistry
- Receptor, Cannabinoid, CB2/metabolism
- Receptors, Cannabinoid/chemistry
- Receptors, Cannabinoid/metabolism
- Software
- Static Electricity
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Affiliation(s)
- Giuseppe Floresta
- Department of Drug Sciences, University of Catania, V.le A. Doria, 95125 Catania, Italy.
- Department of Chemical Sciences, University of Catania, V.le A. Doria, 95125 Catania, Italy.
- Institute of Pharmaceutical Science, King's College London, Stamford Street, London SE1 9NH, UK.
| | - Orapan Apirakkan
- King's Forensics, School of Population Health & Environmental Sciences, King's College London, Franklin-Wilkins Building, 150 Stamford Street, London SE1 9NH, UK.
| | - Antonio Rescifina
- Department of Drug Sciences, University of Catania, V.le A. Doria, 95125 Catania, Italy.
| | - Vincenzo Abbate
- King's Forensics, School of Population Health & Environmental Sciences, King's College London, Franklin-Wilkins Building, 150 Stamford Street, London SE1 9NH, UK.
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13
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Liu Y, Chen LY, Zeng H, Ward R, Wu N, Ma L, Mu X, Li QL, Yang Y, An S, Guo XX, Hao Q, Xu TR. Assessing the real-time activation of the cannabinoid CB1 receptor and the associated structural changes using a FRET biosensor. Int J Biochem Cell Biol 2018; 99:114-124. [PMID: 29626639 DOI: 10.1016/j.biocel.2018.04.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Revised: 03/25/2018] [Accepted: 04/04/2018] [Indexed: 11/18/2022]
Abstract
The cannabinoid receptor 1 (CB1) is mainly expressed in the nervous system and regulates learning, memory processes, pain and energy metabolism. However, there is no way to directly measure its activation. In this study, we constructed a CB1 intramolecular fluorescence resonance energy transfer (FRET) sensor, which could measure CB1 activation by monitoring structural changes between the third intracellular loop and the C-terminal tail. CB1 agonists induced a time- and concentration-dependent increase in the FRET signal, corresponding to a reduction in the distance between the third intracellular loop and the C-terminal tail. This, in turn, mobilized intracellular Ca2+, inhibited cAMP accumulation, and increased phosphorylation of the ERK1/2 MAP kinases. The activation kinetics detected using this method were consistent with those from previous reports. Moreover, the increased FRET signal was markedly inhibited by the CB1 antagonist rimonabant, which also reduced phosphorylation of the ERK1/2 MAP kinases. We mutated a single cysteine residue in the sensor (at position 257 or 264) to alanine. Both mutation reduced the agonist-induced increase in FRET signal and structural changes in the CB1 receptor, which attenuated phosphorylation of the ERK1/2 MAP kinases. In summary, our sensor directly assesses the kinetics of CB1 activation in real-time and can be used to monitor CB1 structure and function.
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Affiliation(s)
- Ying Liu
- Faculty of Life Science and Technology, Kunming University of Science and Technology, Kunming, Yunnan, 650500, China
| | - Lu-Yao Chen
- Faculty of Life Science and Technology, Kunming University of Science and Technology, Kunming, Yunnan, 650500, China
| | - Hong Zeng
- Faculty of Life Science and Technology, Kunming University of Science and Technology, Kunming, Yunnan, 650500, China
| | - Richard Ward
- Center for Translational Pharmacology, Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8QQ, Scotland, United Kingdom
| | - Nan Wu
- Faculty of Life Science and Technology, Kunming University of Science and Technology, Kunming, Yunnan, 650500, China
| | - Li Ma
- Faculty of Life Science and Technology, Kunming University of Science and Technology, Kunming, Yunnan, 650500, China
| | - Xi Mu
- Faculty of Life Science and Technology, Kunming University of Science and Technology, Kunming, Yunnan, 650500, China
| | - Qiu-Lan Li
- Faculty of Life Science and Technology, Kunming University of Science and Technology, Kunming, Yunnan, 650500, China
| | - Yang Yang
- Faculty of Life Science and Technology, Kunming University of Science and Technology, Kunming, Yunnan, 650500, China
| | - Su An
- Faculty of Life Science and Technology, Kunming University of Science and Technology, Kunming, Yunnan, 650500, China
| | - Xiao-Xi Guo
- Faculty of Life Science and Technology, Kunming University of Science and Technology, Kunming, Yunnan, 650500, China
| | - Qian Hao
- Faculty of Life Science and Technology, Kunming University of Science and Technology, Kunming, Yunnan, 650500, China
| | - Tian-Rui Xu
- Faculty of Life Science and Technology, Kunming University of Science and Technology, Kunming, Yunnan, 650500, China.
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14
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Abstract
The cannabinoid receptor 1 (CB1) is a G protein-coupled receptor (GPCR) that is located primarily in the central nervous system. CB1 is a therapeutic target which may impact pathways to mediate pain, neurodegenerative disorders, hunger, and drug-seeking behavior. Despite these benefits, development of orthosteric therapeutic compounds, which target the endogenous ligand-binding site of CB1, has been challenging due to detrimental side effects including psychoactivity, depression, and suicidal thoughts. However, CB1 also has an allosteric binding site(s), which is topographically distinct from the orthosteric site. Allosteric modulation of CB1 has a number of potential advantages including providing a mechanism for more precise control of downstream pathways and circumventing these side effects. In this review, we summarize the concept of allosteric modulation and focus on the structure-activity relationship studies of the well-characterized allosteric modulators, ORG27569 and PSNCBAM-1 and their derivatives, and a few other recent modulators. We review studies on the properties of these modulators on CB1 signaling in cells and their effects in vivo. While many current allosteric modulators also produce complex outcomes, they provide new advances for the design of CB1 centered therapeutics.
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Affiliation(s)
- Rachel Dopart
- a Department of Pharmaceutical Sciences , University of Connecticut , Storrs , CT , USA
| | - Dai Lu
- b Rangel College of Pharmacy , Health Science Center, Texas A&M University , Kingsville , TX , USA
| | - Aron H Lichtman
- c Department of Pharmacology and Toxicology , Virginia Commonwealth University , Richmond , VA , USA
| | - Debra A Kendall
- a Department of Pharmaceutical Sciences , University of Connecticut , Storrs , CT , USA
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15
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Singh P, Ganjiwale A, Howlett AC, Cowsik SM. In silico interaction analysis of cannabinoid receptor interacting protein 1b (CRIP1b) - CB1 cannabinoid receptor. J Mol Graph Model 2017; 77:311-321. [PMID: 28918320 PMCID: PMC5816684 DOI: 10.1016/j.jmgm.2017.09.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2017] [Revised: 09/01/2017] [Accepted: 09/02/2017] [Indexed: 01/16/2023]
Abstract
Cannabinoid Receptor Interacting Protein isoform 1b (CRIP1b) is known to interact with the CB1 receptor. Alternative splicing of the CNRIP1 gene produces CRIP1a and CRIP1b with a difference in the third exon only. Exons 1 and 2 encode for a functional domain in both proteins. CRIP1a is involved in regulating CB1 receptor internalization, but the function of CRIP1b is not very well characterized. Since there are significant identities in functional domains of these proteins, CRIP1b is a potential target for drug discovery. We report here predicted structure of CRIP1b followed by its interaction analysis with CB1 receptor by in-silico methods A number of complementary computational techniques, including, homology modeling, ab-initio and protein threading, were applied to generate three-dimensional molecular models for CRIP1b. The computed model of CRIP1b was refined, followed by docking with C terminus of CB1 receptor to generate a model for the CRIP1b- CB1 receptor interaction. The structure of CRIP1b obtained by homology modelling using RHO_GDI-2 as template is a sandwich fold structure having beta sheets connected by loops, similar to predicted CRIP1a structure. The best scoring refined model of CRIP1b in complex with the CB1 receptor C terminus peptide showed favourable polar interactions. The overall binding pocket of CRIP1b was found to be overlapping to that of CRIP1a. The Arg82 and Cys126 of CRIP1b are involved in the majority of hydrogen bond interactions with the CB1 receptor and are possible key residues required for interactions between the CB1 receptor and CRIP1b.
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Affiliation(s)
- Pratishtha Singh
- School of Life Sciences, Jawaharlal Nehru University, New Delhi 110067, India
| | - Anjali Ganjiwale
- Department of Life Sciences, Bangalore University, Bangalore 560056, India
| | - Allyn C Howlett
- Department of Physiology and Pharmacology, Wake Forest School of Medicine, Winston-Salem, NC 27157, USA
| | - Sudha M Cowsik
- School of Life Sciences, Jawaharlal Nehru University, New Delhi 110067, India.
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16
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Cocci P, Mozzicafreddo M, Angeletti M, Mosconi G, Palermo FA. Differential tissue regulation of peroxisome proliferator-activated receptor α (PPARα) and cannabinoid receptor 1 (CB1) gene transcription pathways by diethylene glycol dibenzoate (DEGB): preliminary observations in a seabream (Sparus aurata) in vivo model. Environ Toxicol Pharmacol 2017; 55:87-93. [PMID: 28843100 DOI: 10.1016/j.etap.2017.08.015] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2017] [Accepted: 08/14/2017] [Indexed: 06/07/2023]
Abstract
Today a variety of endocrine disrupting chemicals (EDCs) are recognized in the group of metabolic disruptors, a wide range of environmental contaminants that alter energy balance regulation by affecting the peroxisome proliferator-activated receptor (PPAR)/retinoid X receptor (RXR) pathway. Herein, we investigated the effect of diethylene glycol dibenzoate (DEGB), a dibenzoate-based plasticizer used as alternative to phthalates, on the expression of key genes involved in lipid metabolism and energy balance by using Sparus aurata juveniles as models. We also evaluated the correlation between cannabinoid receptor 1 (CB1) and PPARα transcriptional patterns in both liver and brain tissues. Exposure to the highest DEGB concentration differentially modulated PPARα/CB1 transcriptional pathways in liver/brain tissues of seabream. We hypothesize that, at peripheral level (i.e. liver), DEGB acts as PPARα agonist resulting in a potential stimulation of key lipolytic genes and a concomitant down-regulation of endocannabinoid metabolic enzyme genes.
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Affiliation(s)
- Paolo Cocci
- School of Biosciences and Veterinary Medicine, University of Camerino, Via Gentile III Da Varano, I-62032 Camerino, MC, Italy
| | - Matteo Mozzicafreddo
- School of Biosciences and Veterinary Medicine, University of Camerino, Via Gentile III Da Varano, I-62032 Camerino, MC, Italy
| | - Mauro Angeletti
- School of Biosciences and Veterinary Medicine, University of Camerino, Via Gentile III Da Varano, I-62032 Camerino, MC, Italy
| | - Gilberto Mosconi
- School of Biosciences and Veterinary Medicine, University of Camerino, Via Gentile III Da Varano, I-62032 Camerino, MC, Italy
| | - Francesco Alessandro Palermo
- School of Biosciences and Veterinary Medicine, University of Camerino, Via Gentile III Da Varano, I-62032 Camerino, MC, Italy.
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17
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Hua T, Vemuri K, Nikas SP, Laprairie RB, Wu Y, Qu L, Pu M, Korde A, Jiang S, Ho JH, Han GW, Ding K, Li X, Liu H, Hanson MA, Zhao S, Bohn LM, Makriyannis A, Stevens RC, Liu ZJ. Crystal structures of agonist-bound human cannabinoid receptor CB 1. Nature 2017; 547:468-471. [PMID: 28678776 PMCID: PMC5793864 DOI: 10.1038/nature23272] [Citation(s) in RCA: 315] [Impact Index Per Article: 45.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2017] [Accepted: 06/15/2017] [Indexed: 12/22/2022]
Abstract
The cannabinoid receptor 1 (CB1) is the principal target of the psychoactive constituent of marijuana, the partial agonist Δ9-tetrahydrocannabinol (Δ9-THC). Here we report two agonist-bound crystal structures of human CB1 in complex with a tetrahydrocannabinol (AM11542) and a hexahydrocannabinol (AM841) at 2.80 Å and 2.95 Å resolution, respectively. The two CB1-agonist complexes reveal important conformational changes in the overall structure, relative to the antagonist-bound state, including a 53% reduction in the volume of the ligand-binding pocket and an increase in the surface area of the G-protein-binding region. In addition, a 'twin toggle switch' of Phe2003.36 and Trp3566.48 (superscripts denote Ballesteros-Weinstein numbering) is experimentally observed and appears to be essential for receptor activation. The structures reveal important insights into the activation mechanism of CB1 and provide a molecular basis for predicting the binding modes of Δ9-THC, and endogenous and synthetic cannabinoids. The plasticity of the binding pocket of CB1 seems to be a common feature among certain class A G-protein-coupled receptors. These findings should inspire the design of chemically diverse ligands with distinct pharmacological properties.
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Affiliation(s)
- Tian Hua
- iHuman Institute, ShanghaiTech University, Shanghai 201210, China
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Kiran Vemuri
- Center for Drug Discovery, Department of Pharmaceutical Sciences; Department of Chemistry and Chemical Biology, Northeastern University, Boston, Massachusetts 02115, USA
| | - Spyros P Nikas
- Center for Drug Discovery, Department of Pharmaceutical Sciences; Department of Chemistry and Chemical Biology, Northeastern University, Boston, Massachusetts 02115, USA
| | - Robert B Laprairie
- Departments of Molecular Medicine and Neuroscience, The Scripps Research Institute, Jupiter, Florida 33458, USA
| | - Yiran Wu
- iHuman Institute, ShanghaiTech University, Shanghai 201210, China
| | - Lu Qu
- iHuman Institute, ShanghaiTech University, Shanghai 201210, China
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Mengchen Pu
- iHuman Institute, ShanghaiTech University, Shanghai 201210, China
| | - Anisha Korde
- Center for Drug Discovery, Department of Pharmaceutical Sciences; Department of Chemistry and Chemical Biology, Northeastern University, Boston, Massachusetts 02115, USA
| | - Shan Jiang
- Center for Drug Discovery, Department of Pharmaceutical Sciences; Department of Chemistry and Chemical Biology, Northeastern University, Boston, Massachusetts 02115, USA
| | - Jo-Hao Ho
- Departments of Molecular Medicine and Neuroscience, The Scripps Research Institute, Jupiter, Florida 33458, USA
| | - Gye Won Han
- Departments of Biological Sciences and Chemistry, Bridge Institute, University of Southern California, Los Angeles, California 90089, USA
| | - Kang Ding
- iHuman Institute, ShanghaiTech University, Shanghai 201210, China
- University of Chinese Academy of Sciences, Beijing 100049, China
- School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Xuanxuan Li
- Complex Systems Division, Beijing Computational Science Research Center, Beijing 100193, China
| | - Haiguang Liu
- Complex Systems Division, Beijing Computational Science Research Center, Beijing 100193, China
| | | | - Suwen Zhao
- iHuman Institute, ShanghaiTech University, Shanghai 201210, China
- School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Laura M Bohn
- Departments of Molecular Medicine and Neuroscience, The Scripps Research Institute, Jupiter, Florida 33458, USA
| | - Alexandros Makriyannis
- Center for Drug Discovery, Department of Pharmaceutical Sciences; Department of Chemistry and Chemical Biology, Northeastern University, Boston, Massachusetts 02115, USA
| | - Raymond C Stevens
- iHuman Institute, ShanghaiTech University, Shanghai 201210, China
- Departments of Biological Sciences and Chemistry, Bridge Institute, University of Southern California, Los Angeles, California 90089, USA
- School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Zhi-Jie Liu
- iHuman Institute, ShanghaiTech University, Shanghai 201210, China
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
- School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
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18
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Eldeeb K, Leone-Kabler S, Howlett AC. Mouse Neuroblastoma CB 1 Cannabinoid Receptor-Stimulated [ 35S]GTPɣS Binding: Total and Antibody-Targeted Gα Protein-Specific Scintillation Proximity Assays. Methods Enzymol 2017; 593:1-21. [PMID: 28750799 PMCID: PMC6535336 DOI: 10.1016/bs.mie.2017.06.028] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
G protein-coupled receptors (GPCRs) are important regulators of cellular signaling functions and therefore are a major target for drug discovery. The CB1 cannabinoid receptor is among the most highly expressed GPCRs in neurons, where it regulates many differentiated neuronal functions. One model system for studying the biochemistry of neuronal responses is the use of neuroblastoma cells originating from the C1300 tumor in the A/J mouse, including cloned cell lines NS20, N2A, N18TG2, N4TG1, and N1E-115, and various immortalized hybrids of neurons with N18TG2 cells. GPCR signal transduction is mediated through interaction with multiple types and subtypes of G proteins that transduce the receptor stimulus to effectors. The [35S]GTPɣS assay provides a valuable pharmacological method to evaluate efficacy and potency in the first step in GPCR signaling. Here, we present detailed protocols for the [35S]GTPɣS-binding assay to measure the total G protein binding and the antibody-targeted scintillation proximity assay to measure specific Gα proteins in neuroblastoma cell membrane preparations. This chapter presents step-by-step methods from cell culture, membrane preparation, assay procedures, and data analysis.
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Affiliation(s)
- Khalil Eldeeb
- Wake Forest School of Medicine, Winston-Salem, NC, United States; Campbell University School of Osteopathic Medicine, Lillington, NC, United States; AL-Azhar Faculty of Medicine, New Damietta, Egypt.
| | | | - Allyn C Howlett
- Wake Forest School of Medicine, Winston-Salem, NC, United States.
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19
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Abstract
The cannabinoid CB1 receptor is abundant in the central nervous system and regulates neuronal transmission and other key physiological processes including those leading to pain, inflammation, memory, and feeding behavior. CB1 is activated by the endogenous ligands, arachidonoyl ethanolamine and 2-arachidonoyl glycerol, by various synthetic ligands (e.g., CP55940), and by Δ9-tetrahydrocannabinol, the psychoactive component of Cannabis sativa. These CB1 ligands are orthosteric and transduce downstream signals by binding CB1 and primarily inducing Gi coupling, but Gs and β-arrestin coupling are also possible. Recently, allosteric modulators for CB1 were discovered that bind to topographically distinct sites and can noncompetitively impact the potency and efficacy of orthosteric compounds. These offer the exciting potential for mechanistic analyses and for developing therapeutics. Yet, it is critical to elucidate whether a compound is a positive allosteric modulator or a negative allosteric modulator of orthosteric ligand-induced CB1 profiles to understand pathway specificity and ameliorate diseases. In this chapter, we present equilibrium and kinetic binding analysis to reveal the impact of allosteric modulators on CB1. Also described are activities consistent with CB1 activation (or inactivation) and include cellular internalization of CB1 and downstream signaling patterns. Since many CB1 allosteric modulators do not enhance G protein coupling, it is critical to distinguish CB1 activation and biased signaling patterns via β-arrestin from CB1 inactivation. These strategies can illuminate pathway specificity and are valuable for the fine-tuning of CB1 function.
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20
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Scott C, Ahn KH, Graf ST, Goddard WA, Kendall DA, Abrol R. Computational Prediction and Biochemical Analyses of New Inverse Agonists for the CB1 Receptor. J Chem Inf Model 2016; 56:201-12. [PMID: 26633590 PMCID: PMC4863456 DOI: 10.1021/acs.jcim.5b00581] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2015] [Indexed: 11/28/2022]
Abstract
Human cannabinoid type 1 (CB1) G-protein coupled receptor is a potential therapeutic target for obesity. The previously predicted and experimentally validated ensemble of ligand-free conformations of CB1 [Scott, C. E. et al. Protein Sci. 2013 , 22 , 101 - 113 ; Ahn, K. H. et al. Proteins 2013 , 81 , 1304 - 1317] are used here to predict the binding sites for known CB1-selective inverse agonists including rimonabant and its seven known derivatives. This binding pocket, which differs significantly from previously published models, is used to identify 16 novel compounds expected to be CB1 inverse agonists by exploiting potential new interactions. We show experimentally that two of these compounds exhibit inverse agonist properties including inhibition of basal and agonist-induced G-protein coupling activity, as well as an enhanced level of CB1 cell surface localization. This demonstrates the utility of using the predicted binding sites for an ensemble of CB1 receptor structures for designing new CB1 inverse agonists.
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Affiliation(s)
- Caitlin
E. Scott
- Materials
and Process Simulation Center, Division of Chemistry and Chemical
Engineering, California Institute of Technology, Pasadena, California 91125, United States
| | - Kwang H. Ahn
- Department
of Pharmaceutical Sciences, University of
Connecticut, Storrs, Connecticut 06269, United States
| | - Steven T. Graf
- Department
of Pharmaceutical Sciences, University of
Connecticut, Storrs, Connecticut 06269, United States
| | - William A. Goddard
- Materials
and Process Simulation Center, Division of Chemistry and Chemical
Engineering, California Institute of Technology, Pasadena, California 91125, United States
| | - Debra A. Kendall
- Department
of Pharmaceutical Sciences, University of
Connecticut, Storrs, Connecticut 06269, United States
| | - Ravinder Abrol
- Materials
and Process Simulation Center, Division of Chemistry and Chemical
Engineering, California Institute of Technology, Pasadena, California 91125, United States
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21
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German N, Decker AM, Gilmour BP, Gay EA, Wiley JL, Thomas BF, Zhang Y. Diarylureas as allosteric modulators of the cannabinoid CB1 receptor: structure-activity relationship studies on 1-(4-chlorophenyl)-3-{3-[6-(pyrrolidin-1-yl)pyridin-2-yl]phenyl}urea (PSNCBAM-1). J Med Chem 2014; 57:7758-69. [PMID: 25162172 PMCID: PMC4175001 DOI: 10.1021/jm501042u] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2014] [Indexed: 12/22/2022]
Abstract
The recent discovery of allosteric modulators of the CB1 receptor including PSNCBAM-1 (4) has generated significant interest in CB1 receptor allosteric modulation. Here in the first SAR study on 4, we have designed and synthesized a series of analogs focusing on modifications at two positions. Pharmacological evaluation in calcium mobilization and binding assays revealed the importance of alkyl substitution at the 2-aminopyridine moiety and electron deficient aromatic groups at the 4-chlorophenyl position for activity at the CB1 receptor, resulting in several analogs with comparable potency to 4. These compounds increased the specific binding of [(3)H]CP55,940, in agreement with previous reports. Importantly, 4 and two analogs dose-dependently reduced the Emax of the agonist curve in the CB1 calcium mobilization assays, confirming their negative allosteric modulator characteristics. Given the side effects associated with CB1 receptor orthosteric antagonists, negative allosteric modulators provide an alternative approach to modulate the pharmacologically important CB1 receptor.
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Affiliation(s)
- Nadezhda German
- Research Triangle Institute, Research
Triangle Park, North Carolina 27709, United States
| | - Ann M. Decker
- Research Triangle Institute, Research
Triangle Park, North Carolina 27709, United States
| | - Brian P. Gilmour
- Research Triangle Institute, Research
Triangle Park, North Carolina 27709, United States
| | - Elaine A. Gay
- Research Triangle Institute, Research
Triangle Park, North Carolina 27709, United States
| | - Jenny L. Wiley
- Research Triangle Institute, Research
Triangle Park, North Carolina 27709, United States
| | - Brian F. Thomas
- Research Triangle Institute, Research
Triangle Park, North Carolina 27709, United States
| | - Yanan Zhang
- Research Triangle Institute, Research
Triangle Park, North Carolina 27709, United States
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22
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Ahmed MH, Kellogg GE, Selley DE, Safo MK, Zhang Y. Predicting the molecular interactions of CRIP1a-cannabinoid 1 receptor with integrated molecular modeling approaches. Bioorg Med Chem Lett 2014; 24:1158-65. [PMID: 24461351 PMCID: PMC4353595 DOI: 10.1016/j.bmcl.2013.12.119] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2013] [Revised: 12/26/2013] [Accepted: 12/29/2013] [Indexed: 12/14/2022]
Abstract
Cannabinoid receptors are a family of G-protein coupled receptors that are involved in a wide variety of physiological processes and diseases. One of the key regulators that are unique to cannabinoid receptors is the cannabinoid receptor interacting proteins (CRIPs). Among them CRIP1a was found to decrease the constitutive activity of the cannabinoid type-1 receptor (CB1R). The aim of this study is to gain an understanding of the interaction between CRIP1a and CB1R through using different computational techniques. The generated model demonstrated several key putative interactions between CRIP1a and CB1R, including the critical involvement of Lys130 in CRIP1a.
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Affiliation(s)
- Mostafa H Ahmed
- Department of Medicinal Chemistry, Virginia Commonwealth University, Richmond, VA 23298, USA; Institute for Structural Biology and Drug Discovery, Virginia Commonwealth University, Richmond, VA 23298, USA
| | - Glen E Kellogg
- Department of Medicinal Chemistry, Virginia Commonwealth University, Richmond, VA 23298, USA; Institute for Structural Biology and Drug Discovery, Virginia Commonwealth University, Richmond, VA 23298, USA; Center for the Study of Biological Complexity, Virginia Commonwealth University, Richmond, VA 23298, USA
| | - Dana E Selley
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, VA 23298, USA
| | - Martin K Safo
- Department of Medicinal Chemistry, Virginia Commonwealth University, Richmond, VA 23298, USA; Institute for Structural Biology and Drug Discovery, Virginia Commonwealth University, Richmond, VA 23298, USA
| | - Yan Zhang
- Department of Medicinal Chemistry, Virginia Commonwealth University, Richmond, VA 23298, USA.
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23
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Jäntti MH, Mandrika I, Kukkonen JP. Human orexin/hypocretin receptors form constitutive homo- and heteromeric complexes with each other and with human CB1 cannabinoid receptors. Biochem Biophys Res Commun 2014; 445:486-90. [PMID: 24530395 DOI: 10.1016/j.bbrc.2014.02.026] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2014] [Accepted: 02/06/2014] [Indexed: 12/17/2022]
Abstract
Human OX1 orexin receptors have been shown to homodimerize and they have also been suggested to heterodimerize with CB1 cannabinoid receptors. The latter has been suggested to be important for orexin receptor responses and trafficking. In this study, we wanted to assess the ability of the other combinations of receptors to also form similar complexes. Vectors for expression of human OX1, OX2 and CB1 receptors, C-terminally fused with either Renilla luciferase or GFP(2) green fluorescent protein variant, were generated. The constructs were transiently expressed in Chinese hamster ovary cells, and constitutive dimerization between the receptors was assessed by bioluminescence energy transfer (BRET). Orexin receptor subtypes readily formed homo- and hetero(di)mers, as suggested by significant BRET signals. CB1 receptors formed homodimers, and they also heterodimerized with both orexin receptors. Interestingly, BRET efficiency was higher for homodimers than for almost all heterodimers. This is likely to be due to the geometry of the interaction; the putatively symmetric dimers may place the C-termini in a more suitable orientation in homomers. Fusion of luciferase to an orexin receptor and GFP(2) to CB1 produced more effective BRET than the opposite fusions, also suggesting differences in geometry. Similar was seen for the OX1-OX2 interaction. In conclusion, orexin receptors have a significant propensity to make homo- and heterodi-/oligomeric complexes. However, it is unclear whether this affects their signaling. As orexin receptors efficiently signal via endocannabinoid production to CB1 receptors, dimerization could be an effective way of forming signal complexes with optimal cannabinoid concentrations available for cannabinoid receptors.
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Affiliation(s)
- Maria H Jäntti
- Department of Veterinary Biosciences, POB 66, FIN-00014 University of Helsinki, Finland.
| | - Ilona Mandrika
- Latvian Biomedical Research and Study Centre, Ratsupites Str. 1, Riga LV 1067, Latvia.
| | - Jyrki P Kukkonen
- Department of Veterinary Biosciences, POB 66, FIN-00014 University of Helsinki, Finland.
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24
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Zheng C, Chen L, Chen X, He X, Yang J, Shi Y, Zhou N. The second intracellular loop of the human cannabinoid CB2 receptor governs G protein coupling in coordination with the carboxyl terminal domain. PLoS One 2013; 8:e63262. [PMID: 23667597 PMCID: PMC3646771 DOI: 10.1371/journal.pone.0063262] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2012] [Accepted: 04/01/2013] [Indexed: 11/18/2022] Open
Abstract
The major effects of cannabinoids and endocannabinoids are mediated via two G protein-coupled receptors, CB1 and CB2, elucidation of the mechanism and structural determinants of the CB2 receptor coupling with G proteins will have a significant impact on drug discovery. In the present study, we systematically investigated the role of the intracellular loops in the interaction of the CB2 receptor with G proteins using chimeric receptors alongside the characterization of cAMP accumulation and ERK1/2 phosphorylation. We provided evidence that ICL2 was significantly involved in G protein coupling in coordination with the C-terminal end. Moreover, a single alanine substitution of the Pro-139 in the CB2 receptor that corresponds to Leu-222 in the CB1 receptor resulted in a moderate impairment in the inhibition of cAMP accumulation, whereas mutants P139F, P139M and P139L were able to couple to the Gs protein in a CRE-driven luciferase assay. With the ERK activation experiments, we further found that P139L has the ability to activate ERK through both Gi- and Gs-mediated pathways. Our findings defined an essential role of the second intracellular loop of the CB2 receptor in coordination with the C-terminal tail in G protein coupling and receptor activation.
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MESH Headings
- Adenylyl Cyclase Inhibitors
- Adenylyl Cyclases/metabolism
- Amino Acid Sequence
- Cell Membrane/drug effects
- Cell Membrane/metabolism
- Cyclic AMP-Dependent Protein Kinases/antagonists & inhibitors
- Cyclic AMP-Dependent Protein Kinases/metabolism
- Enzyme Activation/drug effects
- Extracellular Signal-Regulated MAP Kinases/metabolism
- GTP-Binding Proteins/metabolism
- HEK293 Cells
- Humans
- Molecular Sequence Data
- Mutant Proteins/chemistry
- Mutant Proteins/metabolism
- Proline/metabolism
- Protein Binding/drug effects
- Protein Kinase Inhibitors/pharmacology
- Protein Structure, Secondary
- Protein Structure, Tertiary
- Receptor, Cannabinoid, CB1/chemistry
- Receptor, Cannabinoid, CB1/metabolism
- Receptor, Cannabinoid, CB2/agonists
- Receptor, Cannabinoid, CB2/chemistry
- Receptor, Cannabinoid, CB2/metabolism
- Recombinant Proteins/metabolism
- Signal Transduction/drug effects
- Structure-Activity Relationship
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Affiliation(s)
- Congxia Zheng
- Institute of Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, China
- School of Art, Zhejiang International Studies University, Hangzhou, Zhejiang, China
| | - Linjie Chen
- Institute of Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, China
| | - Xiaopan Chen
- Institute of Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, China
| | - Xiaobai He
- Institute of Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, China
| | - Jingwen Yang
- Institute of Sericulture and Apiculture, College of Animal Sciences, Zhejiang University, Hangzhou, Zhejiang, China
| | - Ying Shi
- Institute of Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, China
| | - Naiming Zhou
- Institute of Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, China
- * E-mail:
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25
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Kusakabe KI, Iso Y, Tada Y, Sakagami M, Morioka Y, Chomei N, Shinonome S, Kawamoto K, Takenaka H, Yasui K, Hamana H, Hanasaki K. Selective CB2 agonists with anti-pruritic activity: discovery of potent and orally available bicyclic 2-pyridones. Bioorg Med Chem 2013; 21:3154-63. [PMID: 23623258 DOI: 10.1016/j.bmc.2013.03.030] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2013] [Revised: 03/15/2013] [Accepted: 03/16/2013] [Indexed: 01/24/2023]
Abstract
The CB2 receptor has emerged as a potential target for the treatment of pruritus as well as pain without CB1-mediated side effects. We previously identified 2-pyridone derivatives 1 and 2 as potent CB2 agonists; however, this series of compounds was found to have unacceptable pharmacokinetic profiles with no significant effect in vivo. To improve these profiles, we performed further structural optimization of 1 and 2, which led to the discovery of bicyclic 2-pyridone 18e with improved CB2 affinity and selectivity over CB1. In a mouse pruritus model, 18e inhibited compound 48/80 induced scratching behavior at a dose of 100 mg/kg. In addition, the docking model of 18e with an active-state CB2 homology model indicated the structural basis of its high affinity and selectivity over CB1.
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MESH Headings
- Administration, Oral
- Animals
- Antipruritics/chemical synthesis
- Antipruritics/pharmacokinetics
- Antipruritics/pharmacology
- Behavior, Animal/drug effects
- Bridged Bicyclo Compounds/chemical synthesis
- Bridged Bicyclo Compounds/pharmacokinetics
- Bridged Bicyclo Compounds/pharmacology
- CHO Cells
- Cricetulus
- Disease Models, Animal
- Drug Discovery
- Mice
- Mice, Inbred ICR
- Molecular Docking Simulation
- Pruritus/drug therapy
- Pruritus/metabolism
- Pruritus/physiopathology
- Pyridones/chemical synthesis
- Pyridones/pharmacokinetics
- Pyridones/pharmacology
- Receptor, Cannabinoid, CB1/chemistry
- Receptor, Cannabinoid, CB2/agonists
- Receptor, Cannabinoid, CB2/chemistry
- Receptor, Cannabinoid, CB2/metabolism
- Structure-Activity Relationship
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Affiliation(s)
- Ken-ichi Kusakabe
- Medicinal Research Laboratories, Shionogi Pharmaceutical Research Center, 11-1 Futaba-cho 3-chome, Toyonaka, Osaka 561-0825, Japan.
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26
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Kargl J, Balenga N, Parzmair GP, Brown AJ, Heinemann A, Waldhoer M. The cannabinoid receptor CB1 modulates the signaling properties of the lysophosphatidylinositol receptor GPR55. J Biol Chem 2012; 287:44234-48. [PMID: 23161546 PMCID: PMC3531739 DOI: 10.1074/jbc.m112.364109] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2012] [Revised: 11/15/2012] [Indexed: 11/06/2022] Open
Abstract
The G protein-coupled receptor (GPCR) 55 (GPR55) and the cannabinoid receptor 1 (CB1R) are co-expressed in many tissues, predominantly in the central nervous system. Seven transmembrane spanning (7TM) receptors/GPCRs can form homo- and heteromers and initiate distinct signaling pathways. Recently, several synthetic CB1 receptor inverse agonists/antagonists, such as SR141716A, AM251, and AM281, were reported to activate GPR55. Of these, SR141716A was marketed as a promising anti-obesity drug, but was withdrawn from the market because of severe side effects. Here, we tested whether GPR55 and CB1 receptors are capable of (i) forming heteromers and (ii) whether such heteromers could exhibit novel signaling patterns. We show that GPR55 and CB1 receptors alter each others signaling properties in human embryonic kidney (HEK293) cells. We demonstrate that the co-expression of FLAG-CB1 receptors in cells stably expressing HA-GPR55 specifically inhibits GPR55-mediated transcription factor activation, such as nuclear factor of activated T-cells and serum response element, as well as extracellular signal-regulated kinases (ERK1/2) activation. GPR55 and CB1 receptors can form heteromers, but the internalization of both receptors is not affected. In addition, we observe that the presence of GPR55 enhances CB1R-mediated ERK1/2 and nuclear factor of activated T-cell activation. Our data provide the first evidence that GPR55 can form heteromers with another 7TM/GPCR and that this interaction with the CB1 receptor has functional consequences in vitro. The GPR55-CB1R heteromer may play an important physiological and/or pathophysiological role in tissues endogenously co-expressing both receptors.
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MESH Headings
- Cannabinoids/metabolism
- Dimerization
- Extracellular Signal-Regulated MAP Kinases/genetics
- Extracellular Signal-Regulated MAP Kinases/metabolism
- HEK293 Cells
- Humans
- Lysophospholipids/metabolism
- Protein Binding
- Receptor, Cannabinoid, CB1/chemistry
- Receptor, Cannabinoid, CB1/genetics
- Receptor, Cannabinoid, CB1/metabolism
- Receptors, Cannabinoid
- Receptors, G-Protein-Coupled/chemistry
- Receptors, G-Protein-Coupled/genetics
- Receptors, G-Protein-Coupled/metabolism
- Signal Transduction
- Transcriptional Activation
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Affiliation(s)
- Julia Kargl
- From the Institute for Experimental and Clinical Pharmacology, Medical University of Graz, 8010 Graz, Austria
| | - Nariman Balenga
- From the Institute for Experimental and Clinical Pharmacology, Medical University of Graz, 8010 Graz, Austria
- the Molecular Signal Transduction Section, Laboratory of Allergic Diseases, NIAID, National Institutes of Health, Bethesda, Maryland 20892-1889
| | - Gerald P. Parzmair
- From the Institute for Experimental and Clinical Pharmacology, Medical University of Graz, 8010 Graz, Austria
| | - Andrew J. Brown
- the Department of Screening and Compound Profiling, GlaxoSmithKline, Medicines Research Centre, Gunnels Wood Road, Stevenage SG1 2NY, United Kingdom, and
| | - Akos Heinemann
- From the Institute for Experimental and Clinical Pharmacology, Medical University of Graz, 8010 Graz, Austria
| | - Maria Waldhoer
- From the Institute for Experimental and Clinical Pharmacology, Medical University of Graz, 8010 Graz, Austria
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27
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Oddi S, Dainese E, Sandiford S, Fezza F, Lanuti M, Chiurchiù V, Totaro A, Catanzaro G, Barcaroli D, De Laurenzi V, Centonze D, Mukhopadhyay S, Selent J, Howlett AC, Maccarrone M. Effects of palmitoylation of Cys(415) in helix 8 of the CB(1) cannabinoid receptor on membrane localization and signalling. Br J Pharmacol 2012; 165:2635-51. [PMID: 21895628 PMCID: PMC3423250 DOI: 10.1111/j.1476-5381.2011.01658.x] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2010] [Revised: 07/15/2011] [Accepted: 08/05/2011] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND AND PURPOSE The CB(1) cannabinoid receptor is regulated by its association with membrane microdomains such as lipid rafts. Here, we investigated the role of palmitoylation of the CB(1) receptor by analysing the functional consequences of site-specific mutation of Cys(415) , the likely site of palmitoylation at the end of helix 8, in terms of membrane association, raft targeting and signalling. EXPERIMENTAL APPROACH The palmitoylation state of CB(1) receptors in rat forebrain was assessed by depalmitoylation/repalmitoylation experiments. Cys(415) was replaced with alanine by site-directed mutagenesis. Green fluorescence protein chimeras of both wild-type and mutant receptors were transiently expressed and functionally characterized in SH-SY5Y cells and HEK-293 cells by means of confocal microscopy, cytofluorimetry and competitive binding assays. Confocal fluorescence recovery after photobleaching was used to assess receptor membrane dynamics, whereas signalling activity was assessed by [(35) S]GTPγS, cAMP and co-immunoprecipitation assays. KEY RESULTS Endogenous CB(1) receptors in rat brain were palmitoylated. Mutation of Cys(415) prevented the palmitoylation of the receptor in transfected cells and reduced its recruitment to plasma membrane and lipid rafts; it also increased protein diffusional mobility. The same mutation markedly reduced the functional coupling of CB(1) receptors with G-proteins and adenylyl cyclase, whereas depalmitoylation abolished receptor association with a specific subset of G-proteins. CONCLUSIONS AND IMPLICATIONS CB(1) receptors were post-translationally modified by palmitoylation. Mutation of Cys(415) provides a receptor that is functionally impaired in terms of membrane targeting and signalling. LINKED ARTICLES This article is part of a themed section on Cannabinoids in Biology and Medicine. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2012.165.issue-8. To view Part I of Cannabinoids in Biology and Medicine visit http://dx.doi.org/10.1111/bph.2011.163.issue-7.
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Affiliation(s)
- Sergio Oddi
- Department of Biomedical Sciences, University of TeramoTeramo, Italy
- European Center for Brain Research (CERC)/Santa Lucia Foundation I.R.C.C.S.Rome, Italy
| | - Enrico Dainese
- Department of Biomedical Sciences, University of TeramoTeramo, Italy
- European Center for Brain Research (CERC)/Santa Lucia Foundation I.R.C.C.S.Rome, Italy
| | - Simone Sandiford
- Neuroscience/Drug Abuse Research Program, Biomedical Biotechnology Research Institute, North Carolina Central UniversityDurham, NC, USA
| | - Filomena Fezza
- European Center for Brain Research (CERC)/Santa Lucia Foundation I.R.C.C.S.Rome, Italy
- Department of Experimental Medicine and Biochemical Sciences, University of Rome ‘Tor Vergata’Rome, Italy
| | - Mirko Lanuti
- Department of Biomedical Sciences, University of TeramoTeramo, Italy
- European Center for Brain Research (CERC)/Santa Lucia Foundation I.R.C.C.S.Rome, Italy
| | - Valerio Chiurchiù
- European Center for Brain Research (CERC)/Santa Lucia Foundation I.R.C.C.S.Rome, Italy
| | - Antonio Totaro
- European Center for Brain Research (CERC)/Santa Lucia Foundation I.R.C.C.S.Rome, Italy
| | - Giuseppina Catanzaro
- Department of Biomedical Sciences, University of TeramoTeramo, Italy
- European Center for Brain Research (CERC)/Santa Lucia Foundation I.R.C.C.S.Rome, Italy
| | - Daniela Barcaroli
- Department of Biomedical Sciences, University of Chieti-Pescara ‘G. d'Annunzio’Chieti, Italy
| | - Vincenzo De Laurenzi
- Department of Biomedical Sciences, University of Chieti-Pescara ‘G. d'Annunzio’Chieti, Italy
| | - Diego Centonze
- European Center for Brain Research (CERC)/Santa Lucia Foundation I.R.C.C.S.Rome, Italy
- Department of Neurosciences, University of Rome ‘Tor Vergata’Rome, Italy
| | - Somnath Mukhopadhyay
- Neuroscience/Drug Abuse Research Program, Biomedical Biotechnology Research Institute, North Carolina Central UniversityDurham, NC, USA
| | - Jana Selent
- Research Group of biomedical Informatics (GRIB-IMIM), University of Pompeu Fabra, Barcelona Biomedical Research Park (PRBB)Barcelona, Spain
| | - Allyn C Howlett
- Department of Physiology and Pharmacology, Wake Forest University Health SciencesWinston-Salem, NC, USA
| | - Mauro Maccarrone
- Department of Biomedical Sciences, University of TeramoTeramo, Italy
- European Center for Brain Research (CERC)/Santa Lucia Foundation I.R.C.C.S.Rome, Italy
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28
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Rozenfeld R, Bushlin I, Gomes I, Tzavaras N, Gupta A, Neves S, Battini L, Gusella GL, Lachmann A, Ma'ayan A, Blitzer RD, Devi LA. Receptor heteromerization expands the repertoire of cannabinoid signaling in rodent neurons. PLoS One 2012; 7:e29239. [PMID: 22235275 PMCID: PMC3250422 DOI: 10.1371/journal.pone.0029239] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2011] [Accepted: 11/23/2011] [Indexed: 11/18/2022] Open
Abstract
A fundamental question in G protein coupled receptor biology is how a single ligand acting at a specific receptor is able to induce a range of signaling that results in a variety of physiological responses. We focused on Type 1 cannabinoid receptor (CB1R) as a model GPCR involved in a variety of processes spanning from analgesia and euphoria to neuronal development, survival and differentiation. We examined receptor dimerization as a possible mechanism underlying expanded signaling responses by a single ligand and focused on interactions between CB1R and delta opioid receptor (DOR). Using co-immunoprecipitation assays as well as analysis of changes in receptor subcellular localization upon co-expression, we show that CB1R and DOR form receptor heteromers. We find that heteromerization affects receptor signaling since the potency of the CB1R ligand to stimulate G-protein activity is increased in the absence of DOR, suggesting that the decrease in CB1R activity in the presence of DOR could, at least in part, be due to heteromerization. We also find that the decrease in activity is associated with enhanced PLC-dependent recruitment of arrestin3 to the CB1R-DOR complex, suggesting that interaction with DOR enhances arrestin-mediated CB1R desensitization. Additionally, presence of DOR facilitates signaling via a new CB1R-mediated anti-apoptotic pathway leading to enhanced neuronal survival. Taken together, these results support a role for CB1R-DOR heteromerization in diversification of endocannabinoid signaling and highlight the importance of heteromer-directed signal trafficking in enhancing the repertoire of GPCR signaling.
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Affiliation(s)
- Raphael Rozenfeld
- Department of Pharmacology and Systems Therapeutics, Mount Sinai School of Medicine, New York, New York, United States of America
| | - Ittai Bushlin
- Department of Pharmacology and Systems Therapeutics, Mount Sinai School of Medicine, New York, New York, United States of America
- Department of Neuroscience and The Friedman Brain Institute, Mount Sinai School of Medicine, New York, New York, United States of America
| | - Ivone Gomes
- Department of Pharmacology and Systems Therapeutics, Mount Sinai School of Medicine, New York, New York, United States of America
| | - Nikos Tzavaras
- Department of Pharmacology and Systems Therapeutics, Mount Sinai School of Medicine, New York, New York, United States of America
| | - Achla Gupta
- Department of Pharmacology and Systems Therapeutics, Mount Sinai School of Medicine, New York, New York, United States of America
| | - Susana Neves
- Department of Pharmacology and Systems Therapeutics, Mount Sinai School of Medicine, New York, New York, United States of America
- Systems Biology Center of New York, Mount Sinai School of Medicine, New York, New York, United States of America
| | - Lorenzo Battini
- Department of Medicine, Mount Sinai School of Medicine, New York, New York, United States of America
| | - G. Luca Gusella
- Department of Medicine, Mount Sinai School of Medicine, New York, New York, United States of America
| | - Alexander Lachmann
- Department of Pharmacology and Systems Therapeutics, Mount Sinai School of Medicine, New York, New York, United States of America
- Systems Biology Center of New York, Mount Sinai School of Medicine, New York, New York, United States of America
| | - Avi Ma'ayan
- Department of Pharmacology and Systems Therapeutics, Mount Sinai School of Medicine, New York, New York, United States of America
- Systems Biology Center of New York, Mount Sinai School of Medicine, New York, New York, United States of America
| | - Robert D. Blitzer
- Department of Pharmacology and Systems Therapeutics, Mount Sinai School of Medicine, New York, New York, United States of America
- Systems Biology Center of New York, Mount Sinai School of Medicine, New York, New York, United States of America
| | - Lakshmi A. Devi
- Department of Pharmacology and Systems Therapeutics, Mount Sinai School of Medicine, New York, New York, United States of America
- Department of Neuroscience and The Friedman Brain Institute, Mount Sinai School of Medicine, New York, New York, United States of America
- Systems Biology Center of New York, Mount Sinai School of Medicine, New York, New York, United States of America
- * E-mail:
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29
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Abstract
Cannabinoids represent a promising class of compounds for developing novel therapeutic agents. Since the isolation and identification of the major psychoactive component Δ(9)-THC in Cannabis sativa in the 1960s, numerous analogues of the classical plant cannabinoids have been synthesized and tested for their biological activity. These compounds primarily target the cannabinoid receptors 1 (CB1) and Cannabinoid receptors 2 (CB2). This chapter focuses on CB1. Despite the lack of crystal structures for CB1, protein-based homology modeling approaches and molecular docking methods can be used in the design and discovery of cannabinoid analogues. Efficient synthetic approaches for therapeutically interesting cannabinoid analogues have been developed to further facilitate the drug discovery process.
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Affiliation(s)
- Chia-En A Chang
- Department of Chemistry, University of California, Riverside, CA, USA.
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30
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Shim JY, Bertalovitz AC, Kendall DA. Identification of essential cannabinoid-binding domains: structural insights into early dynamic events in receptor activation. J Biol Chem 2011; 286:33422-35. [PMID: 21795705 PMCID: PMC3190901 DOI: 10.1074/jbc.m111.261651] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2011] [Revised: 07/20/2011] [Indexed: 12/16/2022] Open
Abstract
The classical cannabinoid agonist HU210, a structural analog of (-)-Δ(9)-tetrahydrocannabinol, binds to brain cannabinoid (CB1) receptors and activates signal transduction pathways. To date, an exact molecular description of the CB1 receptor is not yet available. Utilizing the minor binding pocket of the CB1 receptor as the primary ligand interaction site, we explored HU210 binding using lipid bilayer molecular dynamics (MD) simulations. Among the potential ligand contact residues, we identified residues Phe-174(2.61), Phe-177(2.64), Leu-193(3.29), and Met-363(6.55) as being critical for HU210 binding by mutational analysis. Using these residues to guide the simulations, we determined essential cannabinoid-binding domains in the CB1 receptor, including the highly sought after hydrophobic pocket important for the binding of the C3 alkyl chain of classical and nonclassical cannabinoids. Analyzing the simulations of the HU210-CB1 receptor complex, the CP55940-CB1 receptor complex, and the (-)-Δ(9)-tetrahydrocannabinol-CB1 receptor complex, we found that the positioning of the C3 alkyl chain and the aromatic stacking between Trp-356(6.48) and Trp-279(5.43) is crucial for the Trp-356(6.48) rotamer change toward receptor activation through the rigid-body movement of H6. The functional data for the mutant receptors demonstrated reductions in potency for G protein activation similar to the reductions seen in ligand binding affinity for HU210.
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Affiliation(s)
- Joong-Youn Shim
- JL Chambers Biomedical/Biotechnology Research Institute, North Carolina Central University, Durham, North Carolina 27707, USA.
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31
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Iliff HA, Lynch DL, Kotsikorou E, Reggio PH. Parameterization of Org27569: an allosteric modulator of the cannabinoid CB1 G protein-coupled receptor. J Comput Chem 2011; 32:2119-26. [PMID: 21523790 PMCID: PMC3145811 DOI: 10.1002/jcc.21794] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2011] [Accepted: 02/27/2011] [Indexed: 01/26/2023]
Abstract
The cannabinoid CB1 receptor is a class A G protein-coupled receptor (GPCR) that is the most widely expressed GPCR in the brain. Many GPCRs contain allosteric binding sites for endogenous and/or synthetic ligands, which are topographically distinct from the agonist-binding site that is known as the orthosteric site. While both endogenous and synthetic ligands that act at the CB1 orthosteric site have been known for some time, compounds that act at a CB1 allosteric site have only recently been discovered. The most studied of these is 5-chloro-3-ethyl-1H-indole-2-carboxylic acid [2-(4-piperidin-1-ylphenyl)ethyl]amide (Org27569). Because allosteric ligands are thought to act through conformational changes in the receptor that are transmitted from the allosteric to the orthosteric site, computational studies of the structural and dynamic interactions of Org27569 with the CB1 receptor are crucial to achieve a molecular level understanding of the basis of action of this important new class of compounds. To date, such computational studies have not been possible due to the lack of a complete set of molecular mechanics force field parameters for Org27569. Here, we present the development of missing CHARMM force field parameters for Org27569 using previously published methods and the validation and application of these new parameters using normal mode analysis and molecular dynamics simulations combined with experimental infrared measurements.
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Affiliation(s)
- Hadley A. Iliff
- Center for Drug Discovery, Department of Chemistry and Biochemistry, University of North Carolina at Greensboro, Greensboro, NC 27402
| | - Diane L. Lynch
- Center for Drug Discovery, Department of Chemistry and Biochemistry, University of North Carolina at Greensboro, Greensboro, NC 27402
| | - Evangelia Kotsikorou
- Center for Drug Discovery, Department of Chemistry and Biochemistry, University of North Carolina at Greensboro, Greensboro, NC 27402
| | - Patricia H. Reggio
- Center for Drug Discovery, Department of Chemistry and Biochemistry, University of North Carolina at Greensboro, Greensboro, NC 27402
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32
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Shim JY, Rudd J, Ding TT. Distinct second extracellular loop structures of the brain cannabinoid CB(1) receptor: implication in ligand binding and receptor function. Proteins 2011; 79:581-97. [PMID: 21120862 DOI: 10.1002/prot.22907] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The G-protein-coupled receptor (GPCR) second extracellular loop (E2) is known to play an important role in receptor structure and function. The brain cannabinoid (CB(1)) receptor is unique in that it lacks the interloop E2 disulfide linkage to the transmembrane (TM) helical bundle, a characteristic of many GPCRs. Recent mutation studies of the CB(1) receptor, however, suggest the presence of an alternative intraloop disulfide bond between two E2 Cys residues. Considering the oxidation state of these Cys residues, we determine the molecular structures of the 17-residue E2 in the dithiol form (E2(dithiol)) and in the disulfide form (E2(disulfide)) of the CB(1) receptor in a fully hydrated 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine bilayer, using a combination of simulated annealing and molecular dynamics simulation approaches. We characterize the CB(1) receptor models with these two E2 forms, CB(1)(E2(dithiol)) and CB(1)(E2(disulfide)), by analyzing interaction energy, contact number, core crevice, and cross correlation. The results show that the distinct E2 structures interact differently with the TM helical bundle and uniquely modify the TM helical topology, suggesting that E2 of the CB(1) receptor plays a critical role in stabilizing receptor structure, regulating ligand binding, and ultimately modulating receptor activation. Further studies on the role of E2 of the CB(1) receptor are warranted, particularly comparisons of the ligand-bound form with the present ligand-free form.
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Affiliation(s)
- Joong-Youn Shim
- JL Chambers Biomedical/Biotechnology Research Institute, North Carolina Central University, Durham, North Carolina 27707, USA.
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33
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Moaddel R, Rosenberg A, Spelman K, Frazier J, Frazier C, Nocerino S, Brizzi A, Mugnaini C, Wainer IW. Development and characterization of immobilized cannabinoid receptor (CB1/CB2) open tubular column for on-line screening. Anal Biochem 2011; 412:85-91. [PMID: 21215722 PMCID: PMC3053438 DOI: 10.1016/j.ab.2010.12.034] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2010] [Revised: 12/20/2010] [Accepted: 12/28/2010] [Indexed: 01/23/2023]
Abstract
Cannabinoid receptors, CB1 and CB2, are therapeutic targets in the treatment of anxiety, obesity, movement disorders, glaucoma, and pain. We have developed an on-line screening method for CB1 and CB2 ligands, where cellular membrane fragments of a chronic myelogenous leukemia cell line, KU-812, were immobilized onto the surface of an open tubular (OT) capillary to create a CB1/CB2-OT column. The binding activities of the immobilized CB1/CB2 receptors were established using frontal affinity chromatographic techniques. This is the first report that confirms the presence of functional CB1 and CB2 receptors on KU-812 cells. The data from this study confirm that the CB1/CB2-OT column can be used to determine the binding affinities (K(i) values) for a single compound and to screen individual compounds or a mixture of multiple compounds. The CB1/CB2-OT column was also used to screen a botanical matrix, Zanthoxylum clava-herculis, where preliminary results suggest the presence of a high-affinity phytocannabinoid.
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MESH Headings
- Cannabinoids/chemistry
- Cell Line, Tumor
- Chromatography, Affinity/methods
- Humans
- Immobilized Proteins/chemistry
- Plant Roots/chemistry
- Protein Binding
- Receptor, Cannabinoid, CB1/agonists
- Receptor, Cannabinoid, CB1/chemistry
- Receptor, Cannabinoid, CB2/agonists
- Receptor, Cannabinoid, CB2/chemistry
- Zanthoxylum/chemistry
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Affiliation(s)
- R Moaddel
- Gerontology Research Center, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, USA.
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34
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Ward RJ, Pediani JD, Milligan G. Ligand-induced internalization of the orexin OX(1) and cannabinoid CB(1) receptors assessed via N-terminal SNAP and CLIP-tagging. Br J Pharmacol 2011; 162:1439-52. [PMID: 21175569 PMCID: PMC3058174 DOI: 10.1111/j.1476-5381.2010.01156.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2010] [Revised: 10/26/2010] [Accepted: 11/22/2010] [Indexed: 01/05/2023] Open
Abstract
BACKGROUND AND PURPOSE Many G protein-coupled receptors internalize following agonist binding. The studies were designed to identify novel means to effectively quantify this process using the orexin OX(1) receptor and the cannabinoid CB(1) receptor as exemplars. EXPERIMENTAL APPROACH The human OX(1) and CB(1) receptors were modified to incorporate both epitope tags and variants (SNAP and CLIP) of the enzyme O(6)-alkylguanine-DNA-alkyltransferase within their extracellular, N-terminal domain. Cells able to regulate expression of differing amounts of these constructs upon addition of an antibiotic were developed and analysed. KEY RESULTS Cell surface forms of each receptor construct were detected by both antibody recognition of the epitope tags and covalent binding of fluorophores to the O(6)-alkylguanine-DNA-alkyltransferase variants. Receptor internalization in response to agonists but not antagonists could be monitored by each approach but sensitivity was up to six- to 10-fold greater than other approaches when employing a novel, time-resolved fluorescence probe for the SNAP tag. Sensitivity was not enhanced, however, for the CLIP tag, possibly due to higher levels of nonspecific binding. CONCLUSIONS AND IMPLICATIONS These studies demonstrate that highly sensitive and quantitative assays that monitor cell surface CB(1) and OX(1) receptors and their internalization by agonists can be developed based on introduction of variants of O(6)-alkylguanine-DNA-alkyltransferase into the N-terminal domain of the receptor. This should be equally suitable for other G protein-coupled receptors.
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MESH Headings
- Alkyl and Aryl Transferases/chemistry
- Alkyl and Aryl Transferases/metabolism
- Benzoxazoles/metabolism
- Benzoxazoles/pharmacology
- Cell Line
- Cell Membrane/drug effects
- Cloning, Molecular
- Cyclohexanols/metabolism
- Cyclohexanols/pharmacology
- Extracellular Signal-Regulated MAP Kinases/metabolism
- Humans
- Intracellular Signaling Peptides and Proteins/metabolism
- Intracellular Signaling Peptides and Proteins/pharmacology
- Ligands
- Naphthyridines
- Neuropeptides/metabolism
- Neuropeptides/pharmacology
- Orexin Receptors
- Orexins
- Phenylurea Compounds/metabolism
- Phenylurea Compounds/pharmacology
- Phosphorylation/drug effects
- Piperidines/metabolism
- Piperidines/pharmacology
- Plasmids
- Pyrazoles/metabolism
- Pyrazoles/pharmacology
- Pyrrolidines/metabolism
- Pyrrolidines/pharmacology
- Receptor, Cannabinoid, CB1/agonists
- Receptor, Cannabinoid, CB1/antagonists & inhibitors
- Receptor, Cannabinoid, CB1/chemistry
- Receptor, Cannabinoid, CB1/metabolism
- Receptors, G-Protein-Coupled/agonists
- Receptors, G-Protein-Coupled/antagonists & inhibitors
- Receptors, G-Protein-Coupled/chemistry
- Receptors, G-Protein-Coupled/metabolism
- Receptors, Neuropeptide/agonists
- Receptors, Neuropeptide/antagonists & inhibitors
- Receptors, Neuropeptide/chemistry
- Receptors, Neuropeptide/metabolism
- Rimonabant
- Thiazoles/metabolism
- Thiazoles/pharmacology
- Urea/analogs & derivatives
- Urea/metabolism
- Urea/pharmacology
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Affiliation(s)
- Richard J Ward
- Molecular Pharmacology Group, Neuroscience and Molecular Pharmacology, Faculty of Biomedical and Life Sciences, University of Glasgow, Glasgow G12 8QQ, Scotland, UK
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35
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Hart T, Macias AT, Benwell K, Brooks T, D'Alessandro J, Dokurno P, Francis G, Gibbons B, Haymes T, Kennett G, Lightowler S, Mansell H, Matassova N, Misra A, Padfield A, Parsons R, Pratt R, Robertson A, Walls S, Wong M, Roughley S. Fatty acid amide hydrolase inhibitors. Surprising selectivity of chiral azetidine ureas. Bioorg Med Chem Lett 2009; 19:4241-4. [PMID: 19515560 DOI: 10.1016/j.bmcl.2009.05.097] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2009] [Revised: 05/22/2009] [Accepted: 05/23/2009] [Indexed: 11/20/2022]
Abstract
We report the discovery of a novel, chiral azetidine urea inhibitor of Fatty Acid Amide Hydrolase (FAAH,) and describe the surprising species selectivity of VER-156084 versus rat and human FAAH and also hCB1.
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Affiliation(s)
- Terance Hart
- Vernalis (R&D) Ltd, Granta Park, Cambridge CB21 6GB, UK.
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36
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Tiburu EK, Bowman AL, Struppe JO, Janero DR, Avraham HK, Makriyannis A. Solid-state NMR and molecular dynamics characterization of cannabinoid receptor-1 (CB1) helix 7 conformational plasticity in model membranes. Biochim Biophys Acta 2009; 1788:1159-67. [PMID: 19366584 PMCID: PMC3712639 DOI: 10.1016/j.bbamem.2009.02.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2008] [Revised: 01/30/2009] [Accepted: 02/02/2009] [Indexed: 11/30/2022]
Abstract
Little direct information is available regarding the influence of membrane environment on transmembrane (TM) G-protein-coupled receptor (GPCR) conformation and dynamics. The human CB1 cannabinoid receptor (hCB1) is a prominent GPCR pharmacotherapeutic target in which helix 7 appears critical to ligand recognition. We have chemically synthesized a hCB1 peptide corresponding to a segment of TM helix 7 and the entire contiguous helix 8 domain (fourth cytoplasmic loop) and reconstituted it in defined phospholipid-bilayer model membranes. Using an NMR-based strategy combined with molecular dynamics simulations, we provide the first direct experimental description of the orientation of hCB1 helix 7 in phospholipid membranes of varying thickness and the mechanism by which helix-7 conformation adjusts to avoid hydrophobic mismatch. Solid-state (15)N NMR data show that hCB1 helices 7 and 8 reconstituted into phospholipid bilayers are oriented in a TM and in-plane (i.e., parallel to the phospholipid membrane surface) fashion, respectively. TM helix orientation is influenced by the thickness of the hydrophobic membrane bilayer as well as the interaction of helix 8 with phospholipid polar headgroups. Molecular dynamics simulations show that a decrease in phospholipid chain-length induces a kink at P394 in TM helix 7 to avoid hydrophobic mismatch. Thus, the NP(X)nY motif found in hCB1 and highly conserved throughout the GPCR superfamily is important for flexing helix 7 to accommodate bilayer thickness. Dynamic modulation of hCB1-receptor TM helix conformation by its membrane environment may have general relevance to GPCR structure and function.
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Affiliation(s)
- Elvis K. Tiburu
- Center for Drug Discovery, Northeastern University, Boston, MA 02115, USA
| | - Anna L. Bowman
- Center for Drug Discovery, Northeastern University, Boston, MA 02115, USA
| | | | - David R. Janero
- Center for Drug Discovery, Northeastern University, Boston, MA 02115, USA
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37
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Rediger A, Tarnow P, Bickenbach A, Schaefer M, Krude H, Gruters A, Biebermann H. Heterodimerization of hypothalamic G-protein-coupled receptors involved in weight regulation. Obes Facts 2009; 2:80-6. [PMID: 20054210 PMCID: PMC6444828 DOI: 10.1159/000209862] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
BACKGROUND Melanocortin 3 and 4 receptors (MC3R and MC4R) are known to play an essential role in hypothalamic weight regulation. In addition to these two G-protein-coupled receptors (GPCRs), a huge number of other GPCRs are expressed in hypothalamic regions, and some of them are involved in weight regulation. So far, homodimerization was shown for a few of these receptors. Heterodimerization of unrelated receptors may have profound functional consequence but heterodimerization of GPCRs involved in weight regulation was not reported yet. METHODS A selective number of hypothalamically expressed GPCRs were cloned into a eukaryotic expression vector. Cell surface expression was demonstrated by an ELISA approach. Subcellular distribution was investigated by confocal laser microscopy. A sandwich ELISA and fluorescence resonance energy transfer (FRET) were used to determine protein-protein interaction. RESULTS Via sandwich ELISA and FRET approach we could demonstrate a robust interaction of the MC4R with GPR7, both of which are expressed in the hypothalamic nucleus paraventricularis. Moreover, we determined a strong interaction of MC3R with the growth hormone secretagogue receptor expressed in the nucleus arcuatus. CONCLUSION Identification GPCR heterodimerization adds to the understanding of the complexity of weight regulation and may provide important information to develop therapeutic strategies to treat obesity.
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MESH Headings
- Animals
- Arcuate Nucleus of Hypothalamus/metabolism
- Body Weight/physiology
- COS Cells
- Chlorocebus aethiops
- Dimerization
- Enzyme-Linked Immunosorbent Assay
- Fluorescence Resonance Energy Transfer
- Gene Expression/physiology
- Humans
- Kidney/cytology
- Obesity/genetics
- Obesity/metabolism
- Obesity/physiopathology
- Paraventricular Hypothalamic Nucleus/metabolism
- Receptor, Cannabinoid, CB1/chemistry
- Receptor, Cannabinoid, CB1/genetics
- Receptor, Cannabinoid, CB1/metabolism
- Receptor, Melanocortin, Type 3/chemistry
- Receptor, Melanocortin, Type 3/genetics
- Receptor, Melanocortin, Type 3/metabolism
- Receptor, Melanocortin, Type 4/chemistry
- Receptor, Melanocortin, Type 4/genetics
- Receptor, Melanocortin, Type 4/metabolism
- Receptor, Serotonin, 5-HT1B/chemistry
- Receptor, Serotonin, 5-HT1B/genetics
- Receptor, Serotonin, 5-HT1B/metabolism
- Receptors, Cell Surface/chemistry
- Receptors, Cell Surface/genetics
- Receptors, Cell Surface/metabolism
- Receptors, G-Protein-Coupled/chemistry
- Receptors, G-Protein-Coupled/genetics
- Receptors, G-Protein-Coupled/metabolism
- Receptors, Neuropeptide/chemistry
- Receptors, Neuropeptide/genetics
- Receptors, Neuropeptide/metabolism
- Receptors, Neuropeptide Y/chemistry
- Receptors, Neuropeptide Y/genetics
- Receptors, Neuropeptide Y/metabolism
- Receptors, Opioid, mu/chemistry
- Receptors, Opioid, mu/genetics
- Receptors, Opioid, mu/metabolism
- Receptors, Peptide/chemistry
- Receptors, Peptide/genetics
- Receptors, Peptide/metabolism
- Transfection
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Affiliation(s)
- Anne Rediger
- Institute of Experimental Pediatric Endocrinology, Charité - Universitatsmedizin Berlin, Germany
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38
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Abstract
The human cannabinoid receptor 1 (CB1), a G protein-coupled receptor (GPCR), translocates its long amino-terminal (N-terminal) domain across the endoplasmic reticulum (ER) membrane in a C-to-N terminal direction. Using the Semliki Forest virus (SFV) expression system, CB1 was expressed in baby hamster kidney (BHK) cells. It was found that a large fraction of the CB1 molecules were N-terminally truncated prior to ER translocation. Truncation was fast and independent of the proteasome. It is concluded that the truncation process might be a way to create a novel type of CB1.
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Affiliation(s)
- Rickard Nordström
- Department of Biosciences and Nutrition at Novum, Karolinska Institute, Huddinge, Sweden
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39
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Link AJ, Skretas G, Strauch EM, Chari NS, Georgiou G. Efficient production of membrane-integrated and detergent-soluble G protein-coupled receptors in Escherichia coli. Protein Sci 2008; 17:1857-63. [PMID: 18593817 PMCID: PMC2548370 DOI: 10.1110/ps.035980.108] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2008] [Revised: 06/19/2008] [Accepted: 06/20/2008] [Indexed: 10/21/2022]
Abstract
G protein-coupled receptors (GPCRs) are notoriously difficult to express, particularly in microbial systems. Using GPCR fusions with the green fluorescent protein (GFP), we conducted studies to identify bacterial host effector genes that result in a general and significant enhancement in the amount of membrane-integrated human GPCRs that can be produced in Escherichia coli. We show that coexpression of the membrane-bound AAA+ protease FtsH greatly enhances the expression yield of four different class I GPCRs, irrespective of the presence of GFP. Using this new expression system, we produced 0.5 and 2 mg/L of detergent-solubilized and purified full-length central cannabinoid receptor (CB1) and bradykinin receptor 2 (BR2) in shake flask cultures, respectively, two proteins that had previously eluded expression in microbial systems.
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MESH Headings
- ATP-Dependent Proteases/biosynthesis
- ATP-Dependent Proteases/genetics
- Cell Membrane/chemistry
- Cell Membrane/metabolism
- Detergents/chemistry
- Escherichia coli/genetics
- Escherichia coli/metabolism
- Escherichia coli Proteins/biosynthesis
- Escherichia coli Proteins/genetics
- Green Fluorescent Proteins/biosynthesis
- Humans
- Protein Engineering
- Receptor, Bradykinin B2/biosynthesis
- Receptor, Bradykinin B2/chemistry
- Receptor, Bradykinin B2/isolation & purification
- Receptor, Cannabinoid, CB1/biosynthesis
- Receptor, Cannabinoid, CB1/chemistry
- Receptor, Cannabinoid, CB1/isolation & purification
- Receptors, G-Protein-Coupled/biosynthesis
- Receptors, G-Protein-Coupled/chemistry
- Receptors, G-Protein-Coupled/isolation & purification
- Recombinant Fusion Proteins/biosynthesis
- Recombinant Fusion Proteins/chemistry
- Recombinant Fusion Proteins/isolation & purification
- Solubility
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Affiliation(s)
- A James Link
- Department of Chemical Engineering, The University of Texas at Austin, Austin, Texas 78712, USA
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40
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Palermo FA, Ruggeri B, Mosconi G, Virgili M, Polzonetti-Magni AM. Partial cloning of CB1 cDNA and CB1 mRNA changes in stress responses in the Solea solea. Mol Cell Endocrinol 2008; 286:S52-9. [PMID: 18336994 DOI: 10.1016/j.mce.2008.01.019] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/14/2007] [Revised: 01/22/2008] [Accepted: 01/23/2008] [Indexed: 11/24/2022]
Abstract
Endogenous cannabinoids, through the CB1 receptor, are involved in the control of several functions including stress responses. The aim of this study was to investigate the presence of cannabinoid receptor CB1 in the sole ovary by partial cloning of brain CB1 cDNA; in a stress paradigm of disturbance by handling, which consisted in catching, netting and hand-sorting, changes of CB1 mRNA were related with those of proopiomelanocortin (POMC) mRNA; the trend and timing of stress responses and adaptation were monitored by measuring plasma cortisol levels. We characterized two forms of CB1-like receptor, termed CB1A and CB1B. The two sole CB1 (both 799bp) share 76% identity in their cDNAs, and the deduced amino acid sequences are 80% identical. The handling stress induced a sustained increase in plasma cortisol levels 1h after the handling began and decreased to low levels 12h after initiation of handling, showing the same trend of ovarian POMC mRNA expression. In addition, while CB1A mRNA did not show any significant changes during handling stress, significantly lower levels of CB1B mRNA were found in stressed fish 1h after the beginning of handling, with CB1 expression increased 24h after stress induction, both in the ovary and brain. It can be concluded that endocannabinoid system is involved in the modulation of adaptive responses to environmental conditions.
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MESH Headings
- Amino Acid Sequence
- Animals
- Base Sequence
- Cloning, Molecular
- DNA, Complementary/genetics
- Female
- Flatfishes/genetics
- Gene Expression Regulation
- Hydrocortisone/blood
- Molecular Sequence Data
- Ovary/metabolism
- Pro-Opiomelanocortin/genetics
- Pro-Opiomelanocortin/metabolism
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- Receptor, Cannabinoid, CB1/chemistry
- Receptor, Cannabinoid, CB1/genetics
- Receptor, Cannabinoid, CB1/metabolism
- Sequence Analysis, DNA
- Sequence Homology, Amino Acid
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Affiliation(s)
- F A Palermo
- Dipartimento di Scienze Morfologiche e Biochimiche Comparate, Università degli Studi di Camerino, via Gentile III da Varano, 62032 Camerino (MC), Italy
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41
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Chianese R, Cobellis G, Pierantoni R, Fasano S, Meccariello R. Non-mammalian vertebrate models and the endocannabinoid system: relationships with gonadotropin-releasing hormone. Mol Cell Endocrinol 2008; 286:S46-51. [PMID: 18325658 DOI: 10.1016/j.mce.2008.01.009] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/14/2007] [Revised: 01/18/2008] [Accepted: 01/18/2008] [Indexed: 11/18/2022]
Abstract
Endocannabinoids, via cannabinoid receptors (CB1 and CB2), affect reproductive functions at both local and central level. Due to the high complexity of the endocannabinoid system, to the widespread distribution outside the nervous system and to the high degree of evolutionary conservation, a deep CB1 molecular characterization among species may be useful to elucidate the activity of endocannabinoids at multiple levels. In this review we report CB1 characterization in non-mammalian animal models and, in particular, in the anuran amphibian, the frog, Rana esculenta; we also describe its expression during the annual sexual cycle. Moreover, since reproductive functions are under control of gonadotropin releasing hormone (GnRH), cb1 mRNA and protein expression profile in the forebrain has been compared to those of GnRH-I, the mammalian form primarily involved in gonadotropin release.
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Affiliation(s)
- Rosanna Chianese
- Dipartimento di Medicina Sperimentale, Sez. "F. Bottazzi", II Università di Napoli, Naples, Italy
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42
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Moloney GP, Angus JA, Robertson AD, Stoermer MJ, Robinson M, Wright CE, McRae K, Christopoulos A. Synthesis and cannabinoid activity of 1-substituted-indole-3-oxadiazole derivatives: Novel agonists for the CB1 receptor. Eur J Med Chem 2008; 43:513-39. [PMID: 17582659 DOI: 10.1016/j.ejmech.2007.04.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2006] [Revised: 04/06/2007] [Accepted: 04/12/2007] [Indexed: 10/23/2022]
Abstract
An exploratory chemical effort has been undertaken to develop a novel series of compounds as selective CB(1) agonists. It is hoped that compounds of this type will have clinical utility in pain control, and cerebral ischaemia following stroke or traumatic head injury. We report here medicinal chemistry studies directed towards the investigation of a series of 1-substituted-indole-3-oxadiazoles as potential CB(1) agonists.
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Affiliation(s)
- Gerard P Moloney
- Department of Medicinal Chemistry, Victorian College of Pharmacy (Monash University), 381 Royal Parade Parkville, Victoria, 3052, Australia.
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43
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Bakshi K, Mercier RW, Pavlopoulos S. Interaction of a fragment of the cannabinoid CB1 receptor C-terminus with arrestin-2. FEBS Lett 2007; 581:5009-16. [PMID: 17910957 PMCID: PMC2151313 DOI: 10.1016/j.febslet.2007.09.030] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2007] [Revised: 09/13/2007] [Accepted: 09/14/2007] [Indexed: 11/21/2022]
Abstract
Desensitization of the cannabinoid CB1 receptor is mediated by the interaction with arrestin. In this study, we report the structural changes of a synthetic diphosphorylated peptide corresponding to residues 419-439 of the CB1 C-terminus upon binding to arrestin-2. This segment is pivotal to the desensitization of CB1. Using high-resolution proton NMR, we observe two helical segments in the bound peptide that are separated by the presence a glycine residue. The binding we observe is with a diphoshorylated peptide, whereas a previous study reported binding of a highly phosphorylated rhodopsin fragment to visual arrestin. The arrestin bound conformations of the peptides are compared.
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Affiliation(s)
- Kunal Bakshi
- Department of Pharmaceutical Sciences, University of Connecticut, 69 North Eagleville Road, U-3092, Storrs, CT 06269 USA
| | - Richard W. Mercier
- Center for Drug Discovery, Department of Pharmaceutical Sciences, University of Connecticut, 69 North Eagleville Road, U-3092, Storrs, CT 06269 USA
| | - Spiro Pavlopoulos
- Department of Pharmaceutical Sciences, University of Connecticut, 69 North Eagleville Road, U-3092, Storrs, CT 06269 USA
- * Corresponding Author Dr. Spiro Pavlopoulos, University of Connecticut, School of Pharmacy, Department of Pharmaceutical Sciences, 69 North Eagleville Road, U-3092, Storrs, CT 06269 USA, Ph: 860 486 5413, Fax: 860 486 6857,
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44
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Anavi-Goffer S, Fleischer D, Hurst DP, Lynch DL, Barnett-Norris J, Shi S, Lewis DL, Mukhopadhyay S, Howlett AC, Reggio PH, Abood ME. Helix 8 Leu in the CB1 cannabinoid receptor contributes to selective signal transduction mechanisms. J Biol Chem 2007; 282:25100-13. [PMID: 17595161 DOI: 10.1074/jbc.m703388200] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The intracellular C-terminal helix 8 (H8) of the CB(1) cannabinoid receptor deviates from the highly conserved NPXXY(X)(5,6)F G-protein-coupled receptor motif, possessing a Leu instead of a Phe. We compared the signal transduction capabilities of CB(1) with those of an L7.60F mutation and an L7.60I mutation that mimics the CB(2) sequence. The two mutant receptors differed from wild type (WT) in their ability to regulate G-proteins in the [(35)S]guanosine 5'-3-O-(thio)triphosphate binding assay. The L7.60F receptor exhibited attenuated stimulation by agonists WIN-55,212-2 and CP-55,940 but not HU-210, whereas the L7.60I receptor exhibited impaired stimulation by all agonists tested as well as by the inverse agonist rimonabant. The mutants internalized more rapidly than WT receptors but could equally sequester G-proteins from the somatostatin receptor. Both the time course and maximal N-type Ca(2+) current inhibition by WIN-55,212-2 were reduced in the mutants. Reconstitution experiments with pertussis toxin-insensitive G-proteins revealed loss of coupling to Galpha(i3) but not Galpha(0A) in the L7.60I mutant, whereas the reduction in the time course for the L7.60F mutant was governed by Galpha(i3). Furthermore, Galpha(i3) but not Galpha(0A) enhanced basal facilitation ratio, suggesting that Galpha(i3) is responsible for CB(1) tonic activity. Co-immunoprecipitation studies revealed that both mutant receptors were associated with Galpha(i1) or Galpha(i2) but not with Galpha(i3). Molecular dynamics simulations of WT CB(1) receptor and each mutant in a 1-palmitoyl-2-oleoylphosphatidylcholine bilayer suggested that the packing of H8 is different in each. The hydrogen bonding patterns along the helix backbones of each H8 also are different, as are the geometries of the elbow region of H8 (R7.56(400)-K7.58(402)). This study demonstrates that the evolutionary modification to NPXXY(X)(5,6)L contributes to maximal activity of the CB(1) receptor and provides a molecular basis for the differential coupling observed with chemically different agonists.
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Affiliation(s)
- Sharon Anavi-Goffer
- California Pacific Medical Center Research Institute, San Francisco, California 94107, USA
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45
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Durdagi S, Kapou A, Kourouli T, Andreou T, Nikas SP, Nahmias VR, Papahatjis DP, Papadopoulos MG, Mavromoustakos T. The Application of 3D-QSAR Studies for Novel Cannabinoid Ligands Substituted at the C1‘ Position of the Alkyl Side Chain on the Structural Requirements for Binding to Cannabinoid Receptors CB1 and CB2. J Med Chem 2007; 50:2875-85. [PMID: 17521177 DOI: 10.1021/jm0610705] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A set of 30 novel Delta8-tetrahydrocannabinol and cannabidiol analogues were subjected to three-dimensional quantitative structure-activity relationship studies using the comparative molecular field analysis (CoMFA) and comparative molecular similarity indices analysis (CoMSIA) approaches. Using a combination of molecular modeling techniques and NMR spectroscopy, the putative bioactive conformation of the most potent cannabinoid (CB) ligand in the training set was determined. This conformer was used as the template and CB1 and CB2 pharmacophore models were developed. These models were fitted with experimental binding data and gave high correlation coefficients. Contour maps of the CB1 and CB2 models of CoMFA and CoMSIA approaches show that steric effects dominantly determine the binding affinities. The CoMFA and CoMSIA analyses based on the binding affinity data of CB ligands at the CB1 and CB2 receptors allowed us to deduce the possible optimal binding positions. This information can be used for the design of new CB analogues with enhanced activity and other tailored properties.
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Affiliation(s)
- Serdar Durdagi
- Institute of Organic and Pharmaceutical Chemistry, The National Hellenic Research Foundation, 48 Vas. Constantinou Avenue, 11635 Athens, Greece
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46
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Grace CRR, Cowsik SM, Shim JY, Welsh WJ, Howlett AC. Unique helical conformation of the fourth cytoplasmic loop of the CB1 cannabinoid receptor in a negatively charged environment. J Struct Biol 2007; 159:359-68. [PMID: 17524664 PMCID: PMC2042966 DOI: 10.1016/j.jsb.2007.04.004] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2006] [Revised: 11/27/2006] [Accepted: 04/04/2007] [Indexed: 11/19/2022]
Abstract
The proximal portion of the C-terminus of the CB(1) cannabinoid receptor is a primary determinant for G-protein activation. A 17 residue proximal C-terminal peptide (rodent CB1 401-417), the intracellular loop 4 (IL4) peptide, mimicked the receptor's G-protein activation domain. Because of the importance of the cationic amino acids to G-protein activation, the three-dimensional structure of the IL4 peptide in a negatively charged sodium dodecyl sulfate (SDS) micellar environment has been studied by two-dimensional proton nuclear magnetic resonance (2D (1)H NMR) spectroscopy and distance geometry calculations. Unambiguous proton NMR assignments were carried out with the aid of correlation spectroscopy (DQF-COSY and TOCSY) and nuclear Overhauser effect spectroscopy (NOESY and ROESY) experiments. The distance constraints were used in torsion angle dynamics algorithm for NMR applications (DYANA) to generate a family of structures which were refined using restrained energy minimization and dynamics. In water, the IL4 peptide prefers an extended conformation, whereas in SDS micelles, 3(10)-helical conformation is induced. The predominance of 3(10)-helical domain structure in SDS represents a unique difference compared with structure in alternative environments, which can significantly impact global electrostatic surface potential on the cytoplasmic surface of the CB(1) receptor and might influence the signal to the G-proteins.
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Affiliation(s)
- Christy R. R. Grace
- Post-Graduate Department of Physics, Christ College, Bangalore - 560 029, India
| | - Sudha M. Cowsik
- School of Life Sciences, Jawaharlal Nehru University, New Delhi - 110 067, India
- CORRESPONDING AUTHORS: *Sudha M. Cowsik, Dept. Biochemistry & Mol. Biophysics, Washington University, St. Louis, MO 63110; Phone 314-362-3342; email , *Allyn C. Howlett, Dept. Physiology and Pharmacology, Wake Forest University, Winston-Salem, NC 27157; Phone 336-716-8545; FAX 336-716-8501, email
| | - Joong-Youn Shim
- Neuroscience of Drug Abuse Research Program, Julius L. Chambers Biomedical/Biotechnology Research Institute, North Carolina Central University, Durham, NC 27707
| | - William J. Welsh
- Department of Pharmacology, Univ. Medicine & Dentistry of New Jersey (UMDNJ), Robert Wood Johnson Medical School, and the Informatics Institute of UMDNJ, Piscataway, NJ 08854
| | - Allyn C. Howlett
- Neuroscience of Drug Abuse Research Program, Julius L. Chambers Biomedical/Biotechnology Research Institute, North Carolina Central University, Durham, NC 27707
- CORRESPONDING AUTHORS: *Sudha M. Cowsik, Dept. Biochemistry & Mol. Biophysics, Washington University, St. Louis, MO 63110; Phone 314-362-3342; email , *Allyn C. Howlett, Dept. Physiology and Pharmacology, Wake Forest University, Winston-Salem, NC 27157; Phone 336-716-8545; FAX 336-716-8501, email
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Kapur A, Hurst DP, Fleischer D, Whitnell R, Thakur GA, Makriyannis A, Reggio PH, Abood ME. Mutation studies of Ser7.39 and Ser2.60 in the human CB1 cannabinoid receptor: evidence for a serine-induced bend in CB1 transmembrane helix 7. Mol Pharmacol 2007; 71:1512-24. [PMID: 17384224 DOI: 10.1124/mol.107.034645] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Ligands of structurally diverse natures are able to bind at the CB(1) cannabinoid receptor, suggesting the existence of multiple binding sites on the receptor. Modeling studies have implicated Ser2.60(173) and Ser7.39(383) as possible interaction site(s) for CB(1) agonists. To test the importance of these residues for receptor recognition, recombinant human CB(1) receptors, stably expressed in human embryonic kidney 293 cells, were used to investigate the consequences of mutating Ser2.60 (to S2.60A) or Ser7.39 (to S7.39A) in radioligand binding and guanosine 5'-3-O-(thio)triphosphate functional assays. The S7.39A mutant resulted in a total ablation of [(3)H](-)-3-[2-hydroxyl-4-(1,1-dimethylheptyl)phenyl]-4-[3-hydroxylpropyl] cyclohexan-1-ol (CP55,940) high-affinity binding. However, [(3)H](R)-(+)-[2,3-dihydro-5-methyl-3-[(4-morpholinyl)methyl]-pyrrolo[1,2,3-de]-1,4-benzoxazin-6-yl](1-naphthalenyl)methanone (WIN55,212-2) binding properties at S7.39A were comparable with those of the wild-type (WT) receptor. The binding affinity of (-)-11beta-hydroxy-3-(1',1'-dimethylheptyl)hexahydrocannabinol (AM4056) and (-)-11-hydroxydimethylheptyl-Delta(8)-tetrahydrocannabinol (HU210) were drastically reduced (50- to 100-fold) at the S7.39A mutant. Likewise, the EC(50) for HU210 and AM4056-mediated activation of the S7.39A receptor was increased by >200-fold. In contrast, the binding affinity and potency of WIN55,212-2, CP55,940, HU210, and AM4056 were unaltered at the S2.60A mutant compared with WT human CB(1) receptors. These results clearly suggest that Ser7.39, but not Ser2.60, plays a crucial role in mediating ligand specific interactions for CP55,940, HU210, and AM4056 at the human CB(1) receptor. Our modeling studies predict that Ser7.39 in a g-chi1 conformation may induce a helix bend in TMH7 that provides docking space for CP55,940 binding; the S7.39A mutation may alter this binding space, precluding CP55,940 binding.
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Affiliation(s)
- Ankur Kapur
- California Pacific Medical Center Research Institute, San Francisco, CA 94107, USA
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48
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MESH Headings
- Humans
- Ligands
- Peptide Mapping
- Receptor, Cannabinoid, CB1/chemistry
- Receptor, Cannabinoid, CB1/metabolism
- Receptor, Cannabinoid, CB1/physiology
- Receptor, Cannabinoid, CB2/chemistry
- Receptor, Cannabinoid, CB2/metabolism
- Receptor, Cannabinoid, CB2/physiology
- Receptors, G-Protein-Coupled/chemistry
- Receptors, G-Protein-Coupled/metabolism
- Receptors, G-Protein-Coupled/physiology
- Sequence Homology, Amino Acid
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49
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McDonald NA, Henstridge CM, Connolly CN, Irving AJ. Generation and functional characterization of fluorescent, N-terminally tagged CB1 receptor chimeras for live-cell imaging. Mol Cell Neurosci 2007; 35:237-48. [PMID: 17467290 DOI: 10.1016/j.mcn.2007.02.016] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2006] [Revised: 02/17/2007] [Accepted: 02/23/2007] [Indexed: 11/25/2022] Open
Abstract
N-terminally tagged CB1 receptor fusion proteins, incorporating enhanced green fluorescent protein (GFP) or super-ecliptic pHluorin (SEP), were generated to study CB1 receptor trafficking and cell surface receptor expression in live COS7 and HEK293 cells and hippocampal neurons. An artificial signal sequence (SS) was required for efficient surface expression of CB1 receptor chimeras, which behaved like wild-type CB1 receptors in functional assays. Treatment with cannabinoid ligands led to a rapid down-regulation of SS-GFP-CB1 from the plasma membrane in COS7 and HEK293 cells, associated with trafficking into cytosolic vesicles. Activation of CB1 receptors was also linked with a time-dependent reduction in cell surface SEP-CB1 fluorescence and incorporation of the construct into acidic endosomes, revealed following exposure to NH4Cl. In live hippocampal neurons, SEP-CB1 fluorescence was largely restricted to the axon, consistent with its polarised surface expression. Thus, these new molecular tools are well suited for studying CB1 receptor trafficking and a new generation of GPCR chimeras incorporating SEP at the N-terminus will be especially useful for monitoring dynamic changes in cell surface receptor expression in living cells.
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Affiliation(s)
- Neil A McDonald
- Neurosciences Institute, Division of Pathology and Neuroscience, Ninewells Hospital and Medical School, University of Dundee, Dundee, DD1 9SY, UK
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50
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Lynch DL, Reggio PH. Cannabinoid CB1 receptor recognition of endocannabinoids via the lipid bilayer: molecular dynamics simulations of CB1 transmembrane helix 6 and anandamide in a phospholipid bilayer. J Comput Aided Mol Des 2006; 20:495-509. [PMID: 17106765 DOI: 10.1007/s10822-006-9068-9] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2006] [Accepted: 08/15/2006] [Indexed: 11/30/2022]
Abstract
The phospholipid bilayer plays a central role in the lifecycle of the endogenous cannabinoid, N-arachidonoylethanolamine (anandamide, AEA). Therefore, the orientation and location of AEA in the phospholipid bilayer with respect to key membrane associated proteins, is a central issue in understanding the mechanism of endocannabinoid signaling. In this paper, we report a test of the hypothesis that a betaXXbeta motif (formed by beta branching amino acids, V6.43 and I6.46) on the lipid face of the cannabinoid CB1 receptor in its inactive state may serve as an initial CB1 interaction site for AEA. Eight 6 ns NAMD2 molecular dynamics simulations of AEA were conducted in a model system composed of CB1 transmembrane helix 6 (TMH6) in a 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) bilayer. In addition, eight 6 ns NAMD2 molecular dynamics simulations of a low CB1 affinity (20:2, n-6) analog of AEA were conducted in the same model system. AEA was found to exhibit a higher incidence of V6.43/I6.46 groove insertion than did the (20:2, n-6) analog. In certain cases, AEA established a high energy of interaction with TMH6 by first associating with the V6.43/I6.46 groove and then molding itself to the lipid face of TMH6 to establish a hydrogen bonding interaction with the exposed backbone carbonyl of P6.50. Based upon these results, we propose that the formation of this hydrogen bonded AEA/TMH6 complex may be the initial step in CB1 recognition of AEA in the lipid bilayer.
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Affiliation(s)
- Diane L Lynch
- Center for Drug Design, Department of Chemistry and Biochemistry, University of North Carolina Greensboro, 435 New Science Building, P.O. Box 26170, Greensboro, NC 27402-6170, USA
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