1
|
Brust CA, Swanson MA, Bohn LM. Structural and functional insights into the G protein-coupled receptors: CB1 and CB2. Biochem Soc Trans 2023; 51:1533-1543. [PMID: 37646476 PMCID: PMC10586759 DOI: 10.1042/bst20221316] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Revised: 07/31/2023] [Accepted: 08/01/2023] [Indexed: 09/01/2023]
Abstract
The cannabinoid receptors CB1 and CB2 mediate a variety of physiological processes and continue to be explored as desirable drug targets. Both receptors are activated by the endogenous endocannabinoids and the psychoactive components of marijuana. Over the years, many efforts have been made to make selective ligands; however, the high degree of homology between cannabinoid receptor subtypes introduces challenges in studying either receptor in isolation. Recent advancements in structure biology have resulted in a surge of high-resolution structures, enriching our knowledge and understanding of receptor structure and function. In this review, of recent cannabinoid receptor structures, key features of the inactive and active state CB1 and CB2 are presented. These structures will provide additional insight into the modulation and signaling mechanism of cannabinoid receptors CB1 and CB2 and aid in the development of future therapeutics.
Collapse
Affiliation(s)
- Christina A. Brust
- Department of Molecular Medicine, The Herbert Wertheim UF Scripps Institute for Biomedical Innovation and Technology, Jupiter, FL 33458, U.S.A
- The Skaggs Graduate School of Chemical and Biological Sciences at Scripps Research, La Jolla, CA 92037, U.S.A
| | - Matthew A. Swanson
- Department of Molecular Medicine, The Herbert Wertheim UF Scripps Institute for Biomedical Innovation and Technology, Jupiter, FL 33458, U.S.A
- The Skaggs Graduate School of Chemical and Biological Sciences at Scripps Research, La Jolla, CA 92037, U.S.A
| | - Laura M. Bohn
- Department of Molecular Medicine, The Herbert Wertheim UF Scripps Institute for Biomedical Innovation and Technology, Jupiter, FL 33458, U.S.A
- The Skaggs Graduate School of Chemical and Biological Sciences at Scripps Research, La Jolla, CA 92037, U.S.A
| |
Collapse
|
2
|
Gado F, Ferrisi R, Polini B, Mohamed KA, Ricardi C, Lucarini E, Carpi S, Domenichini F, Stevenson LA, Rapposelli S, Saccomanni G, Nieri P, Ortore G, Pertwee RG, Ghelardini C, Di Cesare Mannelli L, Chiellini G, Laprairie RB, Manera C. Design, Synthesis, and Biological Activity of New CB2 Receptor Ligands: from Orthosteric and Allosteric Modulators to Dualsteric/Bitopic Ligands. J Med Chem 2022; 65:9918-9938. [PMID: 35849804 PMCID: PMC10168668 DOI: 10.1021/acs.jmedchem.2c00582] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The design of dualsteric/bitopic agents as single chemical entities able to simultaneously interact with both the orthosteric and an allosteric binding site represents a novel approach in medicinal chemistry. Biased dualsteric/bitopic agents could enhance certain signaling pathways while diminishing the others that cause unwanted side effects. We have designed, synthesized, and functionally characterized the first CB2R heterobivalent bitopic ligands. In contrast to the parent orthosteric compound, our bitopic ligands selectively target CB2R versus CB1R and show a functional selectivity for the cAMP signaling pathway versus βarrestin2 recruitment. Moreover, the most promising bitopic ligand FD-22a displayed anti-inflammatory activity in a human microglial cell inflammatory model and antinociceptive activity in vivo in an experimental mouse model of neuropathic pain. Finally, computational studies clarified the binding mode of these compounds inside the CB2R, further confirming their bitopic nature.
Collapse
Affiliation(s)
- Francesca Gado
- Department of Pharmacy, University of Pisa, Pisa 56126, Italy
| | - Rebecca Ferrisi
- Department of Pharmacy, University of Pisa, Pisa 56126, Italy
| | - Beatrice Polini
- Department of Pharmacy, University of Pisa, Pisa 56126, Italy.,Department of Pathology, University of Pisa, Pisa 56126, Italy
| | - Kawthar A Mohamed
- College of Pharmacy and Nutrition, University of Saskatchewan, Saskatoon SK S7N 5E5, Canada
| | | | - Elena Lucarini
- Department of Neuroscience, Psychology, Drug Research and Child Health, Section of Pharmacology and Toxicology, University of Florence, Florence 50139, Italy
| | - Sara Carpi
- Department of Pharmacy, University of Pisa, Pisa 56126, Italy.,NEST, Istituto Nanoscienze-CNR and Scuola Normale Superiore, Piazza San Silvestro, Pisa 56126, Italy
| | | | - Lesley A Stevenson
- Institute of Medical Sciences, University of Aberdeen, Aberdeen AB25 2ZD, Scotland, U.K
| | - Simona Rapposelli
- Department of Pharmacy, University of Pisa, Pisa 56126, Italy.,CISUP, Centre for Instrumentation Sharing Pisa University, Lungarno Pacinotti 43, Pisa 56126, Italy
| | | | - Paola Nieri
- Department of Pharmacy, University of Pisa, Pisa 56126, Italy
| | | | - Roger G Pertwee
- Institute of Medical Sciences, University of Aberdeen, Aberdeen AB25 2ZD, Scotland, U.K
| | - Carla Ghelardini
- Department of Neuroscience, Psychology, Drug Research and Child Health, Section of Pharmacology and Toxicology, University of Florence, Florence 50139, Italy
| | - Lorenzo Di Cesare Mannelli
- Department of Neuroscience, Psychology, Drug Research and Child Health, Section of Pharmacology and Toxicology, University of Florence, Florence 50139, Italy
| | - Grazia Chiellini
- Department of Pathology, University of Pisa, Pisa 56126, Italy.,CISUP, Centre for Instrumentation Sharing Pisa University, Lungarno Pacinotti 43, Pisa 56126, Italy
| | - Robert B Laprairie
- College of Pharmacy and Nutrition, University of Saskatchewan, Saskatoon SK S7N 5E5, Canada.,Department of Pharmacology, College of Medicine, Dalhousie University, Halifax B3H 4R2, Nova Scotia, Canada
| | - Clementina Manera
- Department of Pharmacy, University of Pisa, Pisa 56126, Italy.,CISUP, Centre for Instrumentation Sharing Pisa University, Lungarno Pacinotti 43, Pisa 56126, Italy
| |
Collapse
|
3
|
Silva AR, Grosso C, Delerue-Matos C, Rocha JM. Comprehensive review on the interaction between natural compounds and brain receptors: Benefits and toxicity. Eur J Med Chem 2019; 174:87-115. [PMID: 31029947 DOI: 10.1016/j.ejmech.2019.04.028] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2018] [Revised: 04/10/2019] [Accepted: 04/11/2019] [Indexed: 02/06/2023]
Abstract
Given their therapeutic activity, natural products have been used in traditional medicines throughout the centuries. The growing interest of the scientific community in phytopharmaceuticals, and more recently in marine products, has resulted in a significant number of research efforts towards understanding their effect in the treatment of neurodegenerative diseases, such as Alzheimer's (AD), Parkinson (PD) and Huntington (HD). Several studies have shown that many of the primary and secondary metabolites of plants, marine organisms and others, have high affinities for various brain receptors and may play a crucial role in the treatment of diseases affecting the central nervous system (CNS) in mammalians. Actually, such compounds may act on the brain receptors either by agonism, antagonism, allosteric modulation or other type of activity aimed at enhancing a certain effect. The current manuscript comprehensively reviews the state of the art on the interactions between natural compounds and brain receptors. This information is of foremost importance when it is intended to investigate and develop cutting-edge drugs, more effective and with alternative mechanisms of action to the conventional drugs presently used for the treatment of neurodegenerative diseases. Thus, we reviewed the effect of 173 natural products on neurotransmitter receptors, diabetes related receptors, neurotrophic factor related receptors, immune system related receptors, oxidative stress related receptors, transcription factors regulating gene expression related receptors and blood-brain barrier receptors.
Collapse
Affiliation(s)
- Ana R Silva
- Centre of Molecular and Environmental Biology (CBMA), Department of Biology (DB), University of Minho (UM), Campus Gualtar, P-4710-057, Braga, Portugal
| | - Clara Grosso
- REQUIMTE/LAQV, Instituto Superior de Engenharia do Instituto Politécnico do Porto, Rua Dr. António Bernardino de Almeida, 431, P-4249-015, Porto, Portugal.
| | - Cristina Delerue-Matos
- REQUIMTE/LAQV, Instituto Superior de Engenharia do Instituto Politécnico do Porto, Rua Dr. António Bernardino de Almeida, 431, P-4249-015, Porto, Portugal
| | - João M Rocha
- Centre of Molecular and Environmental Biology (CBMA), Department of Biology (DB), University of Minho (UM), Campus Gualtar, P-4710-057, Braga, Portugal; REQUIMTE/LAQV, Grupo de investigação de Química Orgânica Aplicada (QUINOA), Laboratório de polifenóis alimentares, Departamento de Química e Bioquímica (DQB), Faculdade de Ciências da Universidade do Porto (FCUP), Rua do Campo Alegre, s/n, P-4169-007, Porto, Portugal
| |
Collapse
|
4
|
Zhou H, Peng Y, Halikhedkar A, Fan P, Janero DR, Thakur GA, Mercier RW, Sun X, Ma X, Makriyannis A. Human Cannabinoid Receptor 2 Ligand-Interaction Motif: Transmembrane Helix 2 Cysteine, C2.59(89), as Determinant of Classical Cannabinoid Agonist Activity and Binding Pose. ACS Chem Neurosci 2017; 8:1338-1347. [PMID: 28220706 DOI: 10.1021/acschemneuro.7b00003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Cannabinoid receptor 2 (CB2R)-dependent signaling is implicated in neuronal physiology and immune surveillance by brain microglia. Selective CB2R agonists hold therapeutic promise for inflammatory and other neurological disorders. Information on human CB2R (hCB2R) ligand-binding and functional domains is needed to inform the rational design and optimization of candidate druglike hCB2R agonists. Prior demonstration that hCB2R transmembrane helix 2 (TMH2) cysteine C2.59(89) reacts with small-molecule methanethiosulfonates showed that this cysteine residue is accessible to sulfhydryl derivatization reagents. We now report the design and application of two novel, pharmacologically active, high-affinity molecular probes, AM4073 and AM4099, as chemical reporters to interrogate directly the interaction of classical cannabinoid agonists with hCB2R cysteine residues. AM4073 has one electrophilic isothiocyanate (NCS) functionality at the C9 position of its cyclohexenyl C-ring, whereas AM4099 has NCS groups at that position and at the terminus of its aromatic A-ring C3 side chain. Pretreatment of wild-type hCB2R with either probe reduced subsequent [3H]CP55,940 specific binding by ∼60%. Conservative serine substitution of any hCB2R TMH cysteine residue except C2.59(89) did not affect the reduction of [3H]CP55,940 specific binding by either probe, suggesting that AM4073 and AM4099 interact irreversibly with this TMH2 cysteine. In contrast, AM841, an exceptionally potent hCB2R megagonist and direct AM4073/4099 congener bearing a single electrophilic NCS group at the terminus of its C3 side chain, had been demonstrated to bind covalently to TMH6 cysteine C6.47(257) and not C2.59(89). Molecular modeling indicates that the AM4073-hCB2R* interaction at C2.59(89) orients this classical cannabinoid away from TMH6 and toward the TMH2-TMH3 interface in the receptor's hydrophobic binding pocket, whereas the AM841-hCB2R* interaction at C6.47(257) favors agonist orientation toward TMH6/7. These data constitute initial evidence that TMH2 cysteine C2.59(89) is a component of the hCB2R binding pocket for classical cannabinoids. The results further demonstrate how interactions between classical cannabinoids and specific amino acids within the hCB2R* ligand-binding domain act as determinants of agonist pharmacological properties and the architecture of the agonist-hCB2R* conformational ensemble, allowing the receptor to adopt distinct activity states, such that interaction of classical cannabinoids with TMH6 cysteine C6.47(257) favors a binding pose more advantageous for agonist potency than does their interaction with TMH2 cysteine C2.59(89).
Collapse
Affiliation(s)
- Han Zhou
- Center for Drug Discovery and Departments of Chemistry and Chemical Biology, Pharmaceutical Sciences, and Bioengineering; College of Science, Bouvé College of Health Sciences, and College of Engineering, Northeastern University, Boston, Massachusetts 02115-5000, United States
| | - Yan Peng
- Center for Drug Discovery and Departments of Chemistry and Chemical Biology, Pharmaceutical Sciences, and Bioengineering; College of Science, Bouvé College of Health Sciences, and College of Engineering, Northeastern University, Boston, Massachusetts 02115-5000, United States
| | - Aneetha Halikhedkar
- Center for Drug Discovery and Departments of Chemistry and Chemical Biology, Pharmaceutical Sciences, and Bioengineering; College of Science, Bouvé College of Health Sciences, and College of Engineering, Northeastern University, Boston, Massachusetts 02115-5000, United States
| | - Pusheng Fan
- Center for Drug Discovery and Departments of Chemistry and Chemical Biology, Pharmaceutical Sciences, and Bioengineering; College of Science, Bouvé College of Health Sciences, and College of Engineering, Northeastern University, Boston, Massachusetts 02115-5000, United States
| | - David R. Janero
- Center for Drug Discovery and Departments of Chemistry and Chemical Biology, Pharmaceutical Sciences, and Bioengineering; College of Science, Bouvé College of Health Sciences, and College of Engineering, Northeastern University, Boston, Massachusetts 02115-5000, United States
| | - Ganesh A. Thakur
- Center for Drug Discovery and Departments of Chemistry and Chemical Biology, Pharmaceutical Sciences, and Bioengineering; College of Science, Bouvé College of Health Sciences, and College of Engineering, Northeastern University, Boston, Massachusetts 02115-5000, United States
| | - Richard W. Mercier
- Center for Drug Discovery and Departments of Chemistry and Chemical Biology, Pharmaceutical Sciences, and Bioengineering; College of Science, Bouvé College of Health Sciences, and College of Engineering, Northeastern University, Boston, Massachusetts 02115-5000, United States
| | - Xin Sun
- Center for Drug Discovery and Departments of Chemistry and Chemical Biology, Pharmaceutical Sciences, and Bioengineering; College of Science, Bouvé College of Health Sciences, and College of Engineering, Northeastern University, Boston, Massachusetts 02115-5000, United States
| | - Xiaoyu Ma
- Center for Drug Discovery and Departments of Chemistry and Chemical Biology, Pharmaceutical Sciences, and Bioengineering; College of Science, Bouvé College of Health Sciences, and College of Engineering, Northeastern University, Boston, Massachusetts 02115-5000, United States
| | - Alexandros Makriyannis
- Center for Drug Discovery and Departments of Chemistry and Chemical Biology, Pharmaceutical Sciences, and Bioengineering; College of Science, Bouvé College of Health Sciences, and College of Engineering, Northeastern University, Boston, Massachusetts 02115-5000, United States
| |
Collapse
|
5
|
Ragusa G, Gómez-Cañas M, Morales P, Rodríguez-Cueto C, Pazos MR, Asproni B, Cichero E, Fossa P, Pinna GA, Jagerovic N, Fernández-Ruiz J, Murineddu G. New pyridazinone-4-carboxamides as new cannabinoid receptor type-2 inverse agonists: Synthesis, pharmacological data and molecular docking. Eur J Med Chem 2017; 127:398-412. [PMID: 28088085 DOI: 10.1016/j.ejmech.2017.01.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2016] [Revised: 12/04/2016] [Accepted: 01/01/2017] [Indexed: 01/09/2023]
Abstract
In the last few years, cannabinoid type-2 receptor (CB2R) selective ligands have shown a great potential as novel therapeutic drugs in several diseases. With the aim of discovering new selective cannabinoid ligands, a series of pyridazinone-4-carboxamides was designed and synthesized, and the new derivatives tested for their affinity toward the hCB1R and hCB2R. The 6-(4-chloro-3-methylphenyl)-2-(4-fluorobenzyl)-N-(cis-4-methylcyclohexyl)-3-oxo-2,3-dihydropyridazine-4-carboxamide (9) displayed high CB2-affinity (KiCB2 = 2.0 ± 0.81 nM) and a notable selectivity (KiCB1/KiCB2 > 2000). In addition, 9 and other active new synthesized entities have demonstrated to behave as CB2R inverse agonists in [35S]-GTPγS binding assay. ADME predictions of the newly synthesized CB2R ligands suggest a favourable pharmacokinetic profile. Docking studies disclosed the specific pattern of interactions of these derivatives. Our results support that pyridazinone-4-carboxamides represent a new promising scaffold for the development of potent and selective CB2R ligands.
Collapse
Affiliation(s)
- Giulio Ragusa
- Department of Chemistry and Pharmacy, University of Sassari, via F. Muroni 23/A, 07100, Sassari, Italy
| | - María Gómez-Cañas
- Instituto Universitario de Investigación en Neuroquímica, Departamento de Bioquímica y Biología Molecular, Facultad de Medicina, Universidad Complutense, 28040, Madrid, Spain; Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain; Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS), Madrid, Spain
| | - Paula Morales
- Instituto de Química Médica, CSIC, Calle Juan de la Cierva, 3, 28006, Madrid, Spain
| | - Carmen Rodríguez-Cueto
- Instituto Universitario de Investigación en Neuroquímica, Departamento de Bioquímica y Biología Molecular, Facultad de Medicina, Universidad Complutense, 28040, Madrid, Spain; Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain; Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS), Madrid, Spain
| | - María R Pazos
- Instituto Universitario de Investigación en Neuroquímica, Departamento de Bioquímica y Biología Molecular, Facultad de Medicina, Universidad Complutense, 28040, Madrid, Spain; Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain; Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS), Madrid, Spain
| | - Battistina Asproni
- Department of Chemistry and Pharmacy, University of Sassari, via F. Muroni 23/A, 07100, Sassari, Italy
| | - Elena Cichero
- Department of Pharmacy, University of Genoa, Viale Benedetto XV n. 3, 16132, Genoa, Italy
| | - Paola Fossa
- Department of Pharmacy, University of Genoa, Viale Benedetto XV n. 3, 16132, Genoa, Italy
| | - Gerard A Pinna
- Department of Chemistry and Pharmacy, University of Sassari, via F. Muroni 23/A, 07100, Sassari, Italy
| | - Nadine Jagerovic
- Instituto de Química Médica, CSIC, Calle Juan de la Cierva, 3, 28006, Madrid, Spain
| | - Javier Fernández-Ruiz
- Instituto Universitario de Investigación en Neuroquímica, Departamento de Bioquímica y Biología Molecular, Facultad de Medicina, Universidad Complutense, 28040, Madrid, Spain; Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain; Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS), Madrid, Spain
| | - Gabriele Murineddu
- Department of Chemistry and Pharmacy, University of Sassari, via F. Muroni 23/A, 07100, Sassari, Italy.
| |
Collapse
|
6
|
Dore A, Asproni B, Scampuddu A, Gessi S, Murineddu G, Cichero E, Fossa P, Merighi S, Bencivenni S, Pinna GA. Synthesis, molecular modeling and SAR study of novel pyrazolo[5,1-f][1,6]naphthyridines as CB 2 receptor antagonists/inverse agonists. Bioorg Med Chem 2016; 24:5291-5301. [PMID: 27624523 DOI: 10.1016/j.bmc.2016.08.055] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2016] [Revised: 08/05/2016] [Accepted: 08/27/2016] [Indexed: 01/03/2023]
Abstract
Pyrazolo[5,1-f][1,6]naphthyridine-carboxamide derivatives were synthesized and evaluated for the affinity at CB1 and CB2 receptors. Based on the AgOTf and proline-cocatalyzed multicomponent methodology, the ethyl 5-(p-tolyl)pyrazolo[5,1-f][1,6]naphthyridine-2-carboxylate (12) and ethyl 5-(2,4-dichlorophenyl)pyrazolo[5,1-f][1,6]naphthyridine-2-carboxylate (13) intermediates were synthesized from the appropriate o-alkynylaldehydes, p-toluenesulfonyl hydrazide and ethyl pyruvate. Most of the novel compounds feature a p-tolyl (8a-i) or a 2,4-dichlorophenyl (8j) motif at the C5-position of the tricyclic pyrazolo[5,1-f][1,6]naphthyridine scaffold. Structural variation on the carboxamide moiety at the C2-position includes basic monocyclic, terpenoid and adamantine-based amines. Among these derivatives, compound 8h (N-adamant-1-yl-5-(p-tolyl)pyrazolo[5,1-f][1,6]naphthyridine-2-carboxamide) exhibited the highest CB2 receptor affinity (Ki=33nM) and a high degree of selectivity (KiCB1/KiCB2=173:1), whereas a similar trend in the near nM range was seen for the bornyl analogue (compound 8f, Ki=53nM) and the myrtanyl derivative 8j (Ki=67nM). Effects of 8h, 8f and 8j on forskolin-stimulated cAMP levels were determined, showing antagonist/inverse agonist properties for such compounds. Docking studies conducted for these derivatives and the reference antagonist/inverse agonist compound 4 (SR144528) disclosed the specific pattern of interactions probably related to the pyrazolo[5,1-f][1,6]naphthyridine scaffold as CB2 inverse agonists.
Collapse
Affiliation(s)
- Antonio Dore
- Dipartimento di Chimica e Farmacia, Università degli Studi di Sassari, Via F. Muroni 23/a, 07100 Sassari, Italy
| | - Battistina Asproni
- Dipartimento di Chimica e Farmacia, Università degli Studi di Sassari, Via F. Muroni 23/a, 07100 Sassari, Italy.
| | - Alessia Scampuddu
- Dipartimento di Chimica e Farmacia, Università degli Studi di Sassari, Via F. Muroni 23/a, 07100 Sassari, Italy
| | - Stefania Gessi
- Dipartimento di Scienze Mediche, Sezione di Farmacologia, Università di Ferrara, Via Fossato di Mortara, 17-19, 44121 Ferrara, Italy.
| | - Gabriele Murineddu
- Dipartimento di Chimica e Farmacia, Università degli Studi di Sassari, Via F. Muroni 23/a, 07100 Sassari, Italy
| | - Elena Cichero
- Dipartimento di Farmacia, Università di Genova, Viale Benedetto XV n. 3, 16132 Genova, Italy
| | - Paola Fossa
- Dipartimento di Farmacia, Università di Genova, Viale Benedetto XV n. 3, 16132 Genova, Italy
| | - Stefania Merighi
- Dipartimento di Scienze Mediche, Sezione di Farmacologia, Università di Ferrara, Via Fossato di Mortara, 17-19, 44121 Ferrara, Italy
| | - Serena Bencivenni
- Dipartimento di Scienze Mediche, Sezione di Farmacologia, Università di Ferrara, Via Fossato di Mortara, 17-19, 44121 Ferrara, Italy
| | - Gérard A Pinna
- Dipartimento di Chimica e Farmacia, Università degli Studi di Sassari, Via F. Muroni 23/a, 07100 Sassari, Italy
| |
Collapse
|
7
|
Hu J, Feng Z, Ma S, Zhang Y, Tong Q, Alqarni MH, Gou X, Xie XQ. Difference and Influence of Inactive and Active States of Cannabinoid Receptor Subtype CB2: From Conformation to Drug Discovery. J Chem Inf Model 2016; 56:1152-63. [PMID: 27186994 PMCID: PMC5395206 DOI: 10.1021/acs.jcim.5b00739] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Cannabinoid receptor 2 (CB2), a G protein-coupled receptor (GPCR), is a promising target for the treatment of neuropathic pain, osteoporosis, immune system, cancer, and drug abuse. The lack of an experimental three-dimensional CB2 structure has hindered not only the development of studies of conformational differences between the inactive and active CB2 but also the rational discovery of novel functional compounds targeting CB2. In this work, we constructed models of both inactive and active CB2 by homology modeling. Then we conducted two comparative 100 ns molecular dynamics (MD) simulations on the two systems-the active CB2 bound with both the agonist and G protein and the inactive CB2 bound with inverse agonist-to analyze the conformational difference of CB2 proteins and the key residues involved in molecular recognition. Our results showed that the inactive CB2 and the inverse agonist remained stable during the MD simulation. However, during the MD simulations, we observed dynamical details about the breakdown of the "ionic lock" between R131(3.50) and D240(6.30) as well as the outward/inward movements of transmembrane domains of the active CB2 that bind with G proteins and agonist (TM5, TM6, and TM7). All of these results are congruent with the experimental data and recent reports. Moreover, our results indicate that W258(6.48) in TM6 and residues in TM4 (V164(4.56)-L169(4.61)) contribute greatly to the binding of the agonist on the basis of the binding energy decomposition, while residues S180-F183 in extracellular loop 2 (ECL2) may be of importance in recognition of the inverse agonist. Furthermore, pharmacophore modeling and virtual screening were carried out for the inactive and active CB2 models in parallel. Among all 10 hits, two compounds exhibited novel scaffolds and can be used as novel chemical probes for future studies of CB2. Importantly, our studies show that the hits obtained from the inactive CB2 model mainly act as inverse agonist(s) or neutral antagonist(s) at low concentration. Moreover, the hit from the active CB2 model also behaves as a neutral antagonist at low concentration. Our studies provide new insight leading to a better understanding of the structural and conformational differences between two states of CB2 and illuminate the effects of structure on virtual screening and drug design.
Collapse
Affiliation(s)
- Jianping Hu
- Department of Pharmaceutical Sciences and Computational Chemical Genomics Screening Center, School of Pharmacy, NIH National Center of Excellence for Computational Drug Abuse Research, Drug Discovery Institute, and Department of Computational Biology and Structural Biology, School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
- College of Chemistry, Leshan Normal University, Leshan, Sichuan 614004, China
- School of Pharmacy and Bioengineering; Key Laboratory of Medicinal and Edible Plants Resources Development, Chengdu University, Chengdu, Sichuan 610106, China
| | - Zhiwei Feng
- Department of Pharmaceutical Sciences and Computational Chemical Genomics Screening Center, School of Pharmacy, NIH National Center of Excellence for Computational Drug Abuse Research, Drug Discovery Institute, and Department of Computational Biology and Structural Biology, School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
| | - Shifan Ma
- Department of Pharmaceutical Sciences and Computational Chemical Genomics Screening Center, School of Pharmacy, NIH National Center of Excellence for Computational Drug Abuse Research, Drug Discovery Institute, and Department of Computational Biology and Structural Biology, School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
| | - Yu Zhang
- Department of Pharmaceutical Sciences and Computational Chemical Genomics Screening Center, School of Pharmacy, NIH National Center of Excellence for Computational Drug Abuse Research, Drug Discovery Institute, and Department of Computational Biology and Structural Biology, School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
| | - Qin Tong
- Department of Pharmaceutical Sciences and Computational Chemical Genomics Screening Center, School of Pharmacy, NIH National Center of Excellence for Computational Drug Abuse Research, Drug Discovery Institute, and Department of Computational Biology and Structural Biology, School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
| | - Mohammed Hamed Alqarni
- Department of Pharmaceutical Sciences and Computational Chemical Genomics Screening Center, School of Pharmacy, NIH National Center of Excellence for Computational Drug Abuse Research, Drug Discovery Institute, and Department of Computational Biology and Structural Biology, School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
| | - Xiaojun Gou
- School of Pharmacy and Bioengineering; Key Laboratory of Medicinal and Edible Plants Resources Development, Chengdu University, Chengdu, Sichuan 610106, China
| | - Xiang-Qun Xie
- Department of Pharmaceutical Sciences and Computational Chemical Genomics Screening Center, School of Pharmacy, NIH National Center of Excellence for Computational Drug Abuse Research, Drug Discovery Institute, and Department of Computational Biology and Structural Biology, School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
| |
Collapse
|
8
|
Deiana V, Gómez-Cañas M, Pazos MR, Fernández-Ruiz J, Asproni B, Cichero E, Fossa P, Muñoz E, Deligia F, Murineddu G, García-Arencibia M, Pinna GA. Tricyclic pyrazoles. Part 8. Synthesis, biological evaluation and modelling of tricyclic pyrazole carboxamides as potential CB2 receptor ligands with antagonist/inverse agonist properties. Eur J Med Chem 2016; 112:66-80. [PMID: 26890113 DOI: 10.1016/j.ejmech.2016.02.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2015] [Revised: 02/02/2016] [Accepted: 02/03/2016] [Indexed: 10/22/2022]
Abstract
Previous studies have investigated the relevance and structure-activity relationships (SARs) of pyrazole derivatives in relation with cannabinoid receptors, and the series of tricyclic 1,4-dihydroindeno[1,2-c]pyrazoles emerged as potent CB2 receptor ligands. In the present study, novel 1,4-dihydroindeno[1,2-c]pyrazole and 1H-benzo[g]indazole carboxamides containing a cyclopropyl or a cyclohexyl substituent were designed and synthesized to evaluate the influence of these structural modifications towards CB1 and CB2 receptor affinities. Among these derivatives, compound 15 (6-cyclopropyl-1-(2,4-dichlorophenyl)-N-(adamantan-1-yl)-1,4-dihydroindeno[1,2-c]pyrazole-3-carboxamide) showed the highest CB2 receptor affinity (Ki = 4 nM) and remarkable selectivity (KiCB1/KiCB2 = 2232), whereas a similar affinity, within the nM range, was seen for the fenchyl derivative (compound 10: Ki = 6 nM), for the bornyl analogue (compound 14: Ki = 38 nM) and, to a lesser extent, for the aminopiperidine derivative (compound 6: Ki = 69 nM). Compounds 10 and 14 were also highly selective for the CB2 receptor (KiCB1/KiCB2 > 1000), whereas compound 6 was relatively selective (KiCB1/KiCB2 = 27). The four compounds were also subjected to GTPγS binding analysis showing antagonist/inverse agonist properties (IC50 for compound 14 = 27 nM, for 15 = 51 nM, for 10 = 80 nM and for 6 = 294 nM), and this activity was confirmed for the three more active compounds in a CB2 receptor-specific in vitro bioassay consisting in the quantification of prostaglandin E2 release by LPS-stimulated BV2 cells, in the presence and absence of WIN55,212-2 and/or the investigated compounds. Modelling studies were also conducted with the four compounds, which conformed with the structural requirements stated for the binding of antagonist compounds to the human CB2 receptor.
Collapse
Affiliation(s)
- Valeria Deiana
- Dipartimento di Chimica e Farmacia, Università degli Studi di Sassari, via F. Muroni 23/A, 07100 Sassari, Italy
| | - María Gómez-Cañas
- Departamento de Bioquímica y Biología Molecular, Instituto Universitario de Investigación en Neuroquímica, Facultad de Medicina, Universidad Complutense, 28040 Madrid, Spain; Campus de Excelencia Internacional (CEI-Moncloa), Madrid, Spain; Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain; Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS), Madrid, Spain
| | - M Ruth Pazos
- Departamento de Bioquímica y Biología Molecular, Instituto Universitario de Investigación en Neuroquímica, Facultad de Medicina, Universidad Complutense, 28040 Madrid, Spain; Campus de Excelencia Internacional (CEI-Moncloa), Madrid, Spain; Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain; Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS), Madrid, Spain
| | - Javier Fernández-Ruiz
- Departamento de Bioquímica y Biología Molecular, Instituto Universitario de Investigación en Neuroquímica, Facultad de Medicina, Universidad Complutense, 28040 Madrid, Spain; Campus de Excelencia Internacional (CEI-Moncloa), Madrid, Spain; Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain; Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS), Madrid, Spain
| | - Battistina Asproni
- Dipartimento di Chimica e Farmacia, Università degli Studi di Sassari, via F. Muroni 23/A, 07100 Sassari, Italy
| | - Elena Cichero
- Dipartmento di Farmacia, Sezione Chimica del Farmaco e del Prodotto Cosmetico, Università degli Studi di Genova, Viale Benedetto XV, 3, 16132 Genova, Italy
| | - Paola Fossa
- Dipartmento di Farmacia, Sezione Chimica del Farmaco e del Prodotto Cosmetico, Università degli Studi di Genova, Viale Benedetto XV, 3, 16132 Genova, Italy
| | - Eduardo Muñoz
- Maimonides Biomedical Research Institute of Córdoba, Reina Sofía University Hospital, Dept of Cell Biology, Physiology and Immunology, University of Córdoba, Avda Menéndez Pidal s/n, 14004 Córdoba, Spain
| | - Francesco Deligia
- Dipartimento di Chimica e Farmacia, Università degli Studi di Sassari, via F. Muroni 23/A, 07100 Sassari, Italy
| | - Gabriele Murineddu
- Dipartimento di Chimica e Farmacia, Università degli Studi di Sassari, via F. Muroni 23/A, 07100 Sassari, Italy.
| | - Moisés García-Arencibia
- Departamento de Bioquímica y Biología Molecular, Instituto Universitario de Investigación en Neuroquímica, Facultad de Medicina, Universidad Complutense, 28040 Madrid, Spain; Campus de Excelencia Internacional (CEI-Moncloa), Madrid, Spain; Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain; Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS), Madrid, Spain; Grupo de Investigación en Medio Ambiente y Salud, Instituto Universitario de Investigaciones Biomédicas y Sanitarias, Universidad de Las Palmas de Gran Canaria, Spain
| | - Gerard A Pinna
- Dipartimento di Chimica e Farmacia, Università degli Studi di Sassari, via F. Muroni 23/A, 07100 Sassari, Italy
| |
Collapse
|
9
|
Selective CB2 receptor agonists. Part 2: Structure–activity relationship studies and optimization of proline-based compounds. Bioorg Med Chem Lett 2015; 25:581-6. [DOI: 10.1016/j.bmcl.2014.12.019] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2014] [Revised: 12/04/2014] [Accepted: 12/08/2014] [Indexed: 11/17/2022]
|
10
|
Cichero E, Menozzi G, Guariento S, Fossa P. Ligand-based homology modelling of the human CB2 receptor SR144528 antagonist binding site: a computational approach to explore the 1,5-diaryl pyrazole scaffold. MEDCHEMCOMM 2015. [DOI: 10.1039/c5md00333d] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
SR144528 docking mode into the LBHM of the human CB2 receptor antagonist binding site.
Collapse
Affiliation(s)
- Elena Cichero
- Department of Pharmacy
- University of Genoa
- 3 - 16132 Genoa
- Italy
| | - Giulia Menozzi
- Department of Pharmacy
- University of Genoa
- 3 - 16132 Genoa
- Italy
| | - Sara Guariento
- Department of Pharmacy
- University of Genoa
- 3 - 16132 Genoa
- Italy
| | - Paola Fossa
- Department of Pharmacy
- University of Genoa
- 3 - 16132 Genoa
- Italy
| |
Collapse
|
11
|
Feng Z, Alqarni MH, Yang P, Tong Q, Chowdhury A, Wang L, Xie XQ. Modeling, molecular dynamics simulation, and mutation validation for structure of cannabinoid receptor 2 based on known crystal structures of GPCRs. J Chem Inf Model 2014; 54:2483-99. [PMID: 25141027 PMCID: PMC4170816 DOI: 10.1021/ci5002718] [Citation(s) in RCA: 76] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2014] [Indexed: 12/29/2022]
Abstract
The cannabinoid receptor 2 (CB2) plays an important role in the immune system. Although a few of GPCRs crystallographic structures have been reported, it is still challenging to obtain functional transmembrane proteins and high resolution X-ray crystal structures, such as for the CB2 receptor. In the present work, we used 10 reported crystal structures of GPCRs which had high sequence identities with CB2 to construct homology-based comparative CB2 models. We applied these 10 models to perform a prescreen by using a training set consisting of 20 CB2 active compounds and 980 compounds randomly selected from the National Cancer Institute (NCI) database. We then utilized the known 170 cannabinoid receptor 1 (CB1) or CB2 selective compounds for further validation. Based on the docking results, we selected one CB2 model (constructed by β1AR) that was most consistent with the known experimental data, revealing that the defined binding pocket in our CB2 model was well-correlated with the training and testing data studies. Importantly, we identified a potential allosteric binding pocket adjacent to the orthosteric ligand-binding site, which is similar to the reported allosteric pocket for sodium ion Na(+) in the A2AAR and the δ-opioid receptor. Our studies in correlation of our data with others suggested that sodium may reduce the binding affinities of endogenous agonists or its analogs to CB2. We performed a series of docking studies to compare the important residues in the binding pockets of CB2 with CB1, including antagonist, agonist, and our CB2 neutral compound (neutral antagonist) XIE35-1001. Then, we carried out 50 ns molecular dynamics (MD) simulations for the CB2 docked with SR144528 and CP55940, respectively. We found that the conformational changes of CB2 upon antagonist/agonist binding were congruent with recent reports of those for other GPCRs. Based on these results, we further examined one known residue, Val113(3.32), and predicted two new residues, Phe183 in ECL2 and Phe281(7.35), that were important for SR144528 and CP55940 binding to CB2. We then performed site-directed mutation experimental study for these residues and validated the predictions by radiometric binding affinity assay.
Collapse
Affiliation(s)
- Zhiwei Feng
- Department
of Pharmaceutical Sciences and Computational Chemical
Genomics Screening Center, School of Pharmacy, Computational Drug Abuse Research
Center, Drug Discovery Institute, and Department of Computational Biology and Department
of Structural Biology, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, United States
| | - Mohammed Hamed Alqarni
- Department
of Pharmaceutical Sciences and Computational Chemical
Genomics Screening Center, School of Pharmacy, Computational Drug Abuse Research
Center, Drug Discovery Institute, and Department of Computational Biology and Department
of Structural Biology, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, United States
| | - Peng Yang
- Department
of Pharmaceutical Sciences and Computational Chemical
Genomics Screening Center, School of Pharmacy, Computational Drug Abuse Research
Center, Drug Discovery Institute, and Department of Computational Biology and Department
of Structural Biology, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, United States
| | - Qin Tong
- Department
of Pharmaceutical Sciences and Computational Chemical
Genomics Screening Center, School of Pharmacy, Computational Drug Abuse Research
Center, Drug Discovery Institute, and Department of Computational Biology and Department
of Structural Biology, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, United States
| | - Ananda Chowdhury
- Department
of Pharmaceutical Sciences and Computational Chemical
Genomics Screening Center, School of Pharmacy, Computational Drug Abuse Research
Center, Drug Discovery Institute, and Department of Computational Biology and Department
of Structural Biology, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, United States
| | - Lirong Wang
- Department
of Pharmaceutical Sciences and Computational Chemical
Genomics Screening Center, School of Pharmacy, Computational Drug Abuse Research
Center, Drug Discovery Institute, and Department of Computational Biology and Department
of Structural Biology, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, United States
| | - Xiang-Qun Xie
- Department
of Pharmaceutical Sciences and Computational Chemical
Genomics Screening Center, School of Pharmacy, Computational Drug Abuse Research
Center, Drug Discovery Institute, and Department of Computational Biology and Department
of Structural Biology, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, United States
| |
Collapse
|
12
|
Alqarni M, Myint KZ, Tong Q, Yang P, Bartlow P, Wang L, Feng R, Xie XQ. Examining the critical roles of human CB2 receptor residues Valine 3.32 (113) and Leucine 5.41 (192) in ligand recognition and downstream signaling activities. Biochem Biophys Res Commun 2014; 452:334-9. [PMID: 25148941 DOI: 10.1016/j.bbrc.2014.08.048] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2014] [Accepted: 08/11/2014] [Indexed: 11/19/2022]
Abstract
We performed molecular modeling and docking to predict a putative binding pocket and associated ligand-receptor interactions for human cannabinoid receptor 2 (CB2). Our data showed that two hydrophobic residues came in close contact with three structurally distinct CB2 ligands: CP-55,940, SR144528 and XIE95-26. Site-directed mutagenesis experiments and subsequent functional assays implicated the roles of Valine residue at position 3.32 (V113) and Leucine residue at position 5.41 (L192) in the ligand binding function and downstream signaling activities of the CB2 receptor. Four different point mutations were introduced to the wild type CB2 receptor: V113E, V113L, L192S and L192A. Our results showed that mutation of Val113 with a Glutamic acid and Leu192 with a Serine led to the complete loss of CB2 ligand binding as well as downstream signaling activities. Substitution of these residues with those that have similar hydrophobic side chains such as Leucine (V113L) and Alanine (L192A), however, allowed CB2 to retain both its ligand binding and signaling functions. Our modeling results validated by competition binding and site-directed mutagenesis experiments suggest that residues V113 and L192 play important roles in ligand binding and downstream signaling transduction of the CB2 receptor.
Collapse
Affiliation(s)
- Mohammed Alqarni
- Department of Pharmaceutical Sciences and Computational Chemical Genomics Screening Center, School of Pharmacy, Pittsburgh, PA 15260, USA
| | - Kyaw Zeyar Myint
- Department of Pharmaceutical Sciences and Computational Chemical Genomics Screening Center, School of Pharmacy, Pittsburgh, PA 15260, USA; Joint Carnegie Mellon University-University of Pittsburgh Ph.D. Program, Department of Computational Biology and Structural Biology, School of Medicine, Pittsburgh, PA 15260, USA
| | - Qin Tong
- Department of Pharmaceutical Sciences and Computational Chemical Genomics Screening Center, School of Pharmacy, Pittsburgh, PA 15260, USA
| | - Peng Yang
- Department of Pharmaceutical Sciences and Computational Chemical Genomics Screening Center, School of Pharmacy, Pittsburgh, PA 15260, USA
| | - Patrick Bartlow
- Department of Pharmaceutical Sciences and Computational Chemical Genomics Screening Center, School of Pharmacy, Pittsburgh, PA 15260, USA
| | - Lirong Wang
- Department of Pharmaceutical Sciences and Computational Chemical Genomics Screening Center, School of Pharmacy, Pittsburgh, PA 15260, USA
| | - Rentian Feng
- Department of Pharmaceutical Sciences and Computational Chemical Genomics Screening Center, School of Pharmacy, Pittsburgh, PA 15260, USA
| | - Xiang-Qun Xie
- Department of Pharmaceutical Sciences and Computational Chemical Genomics Screening Center, School of Pharmacy, Pittsburgh, PA 15260, USA; Joint Carnegie Mellon University-University of Pittsburgh Ph.D. Program, Department of Computational Biology and Structural Biology, School of Medicine, Pittsburgh, PA 15260, USA; Drug Discovery Institute, University of Pittsburgh, Pittsburgh, PA 15260, USA.
| |
Collapse
|
13
|
Mastering tricyclic ring systems for desirable functional cannabinoid activity. Eur J Med Chem 2013; 69:881-907. [PMID: 24125850 DOI: 10.1016/j.ejmech.2013.09.038] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2013] [Revised: 09/16/2013] [Accepted: 09/19/2013] [Indexed: 11/23/2022]
Abstract
There is growing interest in using cannabinoid receptor 2 (CB2) agonists for the treatment of neuropathic pain and other indications. In continuation of our ongoing program aiming for the development of new small molecule cannabinoid ligands, we have synthesized a novel series of carbazole and γ-carboline derivatives. The affinities of the newly synthesized compounds were determined by a competitive radioligand displacement assay for human CB2 cannabinoid receptor and rat CB1 cannabinoid receptor. Functional activity and selectivity at human CB1 and CB2 receptors were characterized using receptor internalization and [(35)S]GTP-γ-S assays. The structure-activity relationship and optimization studies of the carbazole series have led to the discovery of a non-selective CB1 and CB2 agonist, compound 4. Our subsequent research efforts to increase CB2 selectivity of this lead compound have led to the discovery of CB2 selective compound 64, which robustly internalized CB2 receptors. Compound 64 had potent inhibitory effects on pain hypersensitivity in a rat model of neuropathic pain. Other potent and CB2 receptor-selective compounds, including compounds 63 and 68, and a selective CB1 agonist, compound 74 were also discovered. In addition, we identified the CB2 ligand 35 which failed to promote CB2 receptor internalization and inhibited compound CP55,940-induced CB2 internalization despite a high CB2 receptor affinity. The present study provides novel tricyclic series as a starting point for further investigations of CB2 pharmacology and pain treatment.
Collapse
|
14
|
Kotsikorou E, Navas F, Roche MJ, Gilliam AF, Thomas B, Seltzman HH, Kumar P, Song ZH, Hurst DP, Lynch DL, Reggio PH. The importance of hydrogen bonding and aromatic stacking to the affinity and efficacy of cannabinoid receptor CB2 antagonist, 5-(4-chloro-3-methylphenyl)-1-[(4-methylphenyl)methyl]-N-[(1S,2S,4R)-1,3,3-trimethylbicyclo[2.2.1]hept-2-yl]-1H-pyrazole-3-carboxamide (SR144528). J Med Chem 2013; 56:6593-612. [PMID: 23855811 PMCID: PMC3804063 DOI: 10.1021/jm400070u] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Despite the therapeutic promise of the subnanomolar affinity cannabinoid CB2 antagonist, 5-(4-chloro-3-methylphenyl)-1-[(4-methylphenyl)methyl]-N-[(1S,2S,4R)-1,3,3-trimethylbicyclo[2.2.1]hept-2-yl]-1H-pyrazole-3-carboxamide (SR144528, 1), little is known about its binding site interactions and no primary interaction site for 1 at CB2 has been identified. We report here the results of Glide docking studies in our cannabinoid CB2 inactive state model that were then tested via compound synthesis, binding, and functional assays. Our results show that the amide functional group of 1 is critical to its CB2 affinity and efficacy and that aromatic stacking interactions in the TMH5/6 aromatic cluster of CB2 are also important. Molecular modifications that increased the positive electrostatic potential in the region between the fenchyl and aromatic rings led to more efficacious compounds. This result is consistent with the EC-3 loop negatively charged amino acid, D275 (identified via Glide docking studies) acting as the primary interaction site for 1 and its analogues.
Collapse
Affiliation(s)
| | - Frank Navas
- Research Triangle Institute, Research Triangle Park, NC 27609
| | | | - Anne F. Gilliam
- Research Triangle Institute, Research Triangle Park, NC 27609
| | - Brian Thomas
- Research Triangle Institute, Research Triangle Park, NC 27609
| | | | - Pritesh Kumar
- Department of Pharmacology and Toxicology, University of Louisville, University of Louisville School of Medicine, Louisville, KY 40292
| | - Zhao-Hui Song
- Department of Pharmacology and Toxicology, University of Louisville, University of Louisville School of Medicine, Louisville, KY 40292
| | - Dow P. Hurst
- 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
| | - Patricia H. Reggio
- Center for Drug Discovery, Department of Chemistry and Biochemistry, University of North Carolina at Greensboro, Greensboro, NC 27402
| |
Collapse
|
15
|
Yang P, Myint KZ, Tong Q, Feng R, Cao H, Almehizia AA, Alqarni MH, Wang L, Bartlow P, Gao Y, Gertsch J, Teramachi J, Kurihara N, Roodman GD, Cheng T, Xie XQ. Lead discovery, chemistry optimization, and biological evaluation studies of novel biamide derivatives as CB2 receptor inverse agonists and osteoclast inhibitors. J Med Chem 2012; 55:9973-87. [PMID: 23072339 DOI: 10.1021/jm301212u] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
N,N'-((4-(Dimethylamino)phenyl)methylene)bis(2-phenylacetamide) was discovered by using 3D pharmacophore database searches and was biologically confirmed as a new class of CB(2) inverse agonists. Subsequently, 52 derivatives were designed and synthesized through lead chemistry optimization by modifying the rings A-C and the core structure in further SAR studies. Five compounds were developed and also confirmed as CB(2) inverse agonists with the highest CB(2) binding affinity (CB(2)K(i) of 22-85 nM, EC(50) of 4-28 nM) and best selectivity (CB(1)/CB(2) of 235- to 909-fold). Furthermore, osteoclastogenesis bioassay indicated that PAM compounds showed great inhibition of osteoclast formation. Especially, compound 26 showed 72% inhibition activity even at the low concentration of 0.1 μM. The cytotoxicity assay suggested that the inhibition of PAM compounds on osteoclastogenesis did not result from its cytotoxicity. Therefore, these PAM derivatives could be used as potential leads for the development of a new type of antiosteoporosis agent.
Collapse
Affiliation(s)
- Peng Yang
- Department of Pharmaceutical Sciences and Computational Chemical Genomics Screening Center, School of Pharmacy, University of Pittsburgh , Pittsburgh, Pennsylvania 15260, USA
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
16
|
Shim JY. Understanding functional residues of the cannabinoid CB1. Curr Top Med Chem 2011; 10:779-98. [PMID: 20370713 DOI: 10.2174/156802610791164210] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2009] [Accepted: 10/27/2009] [Indexed: 02/07/2023]
Abstract
The brain cannabinoid (CB(1)) receptor that mediates numerous physiological processes in response to marijuana and other psychoactive compounds is a G protein coupled receptor (GPCR) and shares common structural features with many rhodopsin class GPCRs. For the rational development of therapeutic agents targeting the CB(1) receptor, understanding of the ligand-specific CB(1) receptor interactions responsible for unique G protein signals is crucial. For a more than a decade, a combination of mutagenesis and computational modeling approaches has been successfully employed to study the ligand-specific CB(1) receptor interactions. In this review, after a brief discussion about recent advances in understanding of some structural and functional features of GPCRs commonly applicable to the CB(1) receptor, the CB(1) receptor functional residues reported from mutational studies are divided into three different types, ligand binding (B), receptor stabilization (S) and receptor activation (A) residues, to delineate the nature of the binding pockets of anandamide, CP55940, WIN55212-2 and SR141716A and to describe the molecular events of the ligand-specific CB(1) receptor activation from ligand binding to G protein signaling. Taken these CB(1) receptor functional residues, some of which are unique to the CB(1) receptor, together with the biophysical knowledge accumulated for the GPCR active state, it is possible to propose the early stages of the CB(1) receptor activation process that not only provide some insights into understanding molecular mechanisms of receptor activation but also are applicable for identifying new therapeutic agents by applying the validated structure-based approaches, such as virtual high throughput screening (HTS) and fragment-based approach (FBA).
Collapse
Affiliation(s)
- Joong-Youn Shim
- J.L. Chambers Biomedical/Biotechnology Research Institute, North Carolina Central University, 700 George Street, Durham, NC 27707, USA.
| |
Collapse
|
17
|
Zhang Y, Xie Z, Wang L, Schreiter B, Lazo JS, Gertsch J, Xie XQ. Mutagenesis and computer modeling studies of a GPCR conserved residue W5.43(194) in ligand recognition and signal transduction for CB2 receptor. Int Immunopharmacol 2011; 11:1303-10. [PMID: 21539938 DOI: 10.1016/j.intimp.2011.04.013] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2010] [Revised: 04/15/2011] [Accepted: 04/18/2011] [Indexed: 10/18/2022]
Abstract
W5.43(194), a conserved tryptophan residue among G-protein coupled receptors (GPCRs) and cannabinoid receptors (CB), was examined in the present report for its significance in CB2 receptor ligand binding and adenylyl cyclase (AC) activity. Computer modeling postulates that this site in CB2 may be involved in the affinity of WIN55212-2 and SR144528 through aromatic contacts. In the present study, we reported that a CB2 receptor mutant, W5.43(194)Y, which had a tyrosine (Y) substitution for tryptophan (W), retained the binding affinity for CB agonist CP55940, but reduced binding affinity for CB2 agonist WIN55212-2 and inverse agonist SR144528 by 8-fold and 5-fold, respectively; the CB2 W5.43(194)F and W5.43(194)A mutations significantly affect the binding activities of CP55940, WIN55212-2 and SR144528. Furthermore, we found that agonist-mediated inhibition of the forskolin-induced cAMP production was dramatically diminished in the CB2 mutant W5.43(194)Y, whereas W5.43(194)F and W5.43(194)A mutants resulted in complete elimination of downstream signaling, suggesting that W5.43(194) was essential for the full activation of CB2. These results indicate that both aromatic interaction and hydrogen bonding are involved in ligand binding for the residue W5.43(194), and the mutations of this tryptophan site may affect the conformation of the ligand binding pocket and therefore control the active conformation of the wild type CB2 receptor. W5.43(194)Y/F/A mutations also displayed noticeable enhancement of the constitutive activation probably attributed to the receptor conformational changes resulted from the mutations.
Collapse
Affiliation(s)
- Yuxun Zhang
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | | | | | | | | | | | | |
Collapse
|
18
|
Fan Y, Hooker BA, Garrison TR, El-Kouhen OF, Idler KB, Holley-Shanks RR, Meyer MD, Yao BB. Pharmacological and molecular characterization of a dorsal root ganglion cell line expressing cannabinoid CB(1) and CB(2) receptors. Eur J Pharmacol 2011; 659:161-8. [PMID: 21458448 DOI: 10.1016/j.ejphar.2011.03.020] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2010] [Revised: 01/19/2011] [Accepted: 03/08/2011] [Indexed: 10/18/2022]
Abstract
The behavioral effects evoked by cannabinoids are primarily mediated by the CB(1) and CB(2) cannabinoid receptor subtypes. In vitro pharmacology of cannabinoid receptors has been elucidated using recombinant expression systems expressing either CB(1) or CB(2) receptors, with limited characterization in native cell lines endogenously expressing both CB(1) and CB(2) receptors. In the current study, we report the molecular and pharmacological characterization of the F-11 cell line, a hybridoma of rat dorsal root ganglion neurons and mouse neuroblastoma (N18TG2) cells, reported to endogenously express both cannabinoid receptors. The present study revealed that both receptors are of mouse origin in F-11 cells, and describes the relative gene expression levels between the two receptors. Pharmacological characterization of the F-11 cell line using cannabinoid agonists and antagonists indicated that the functional responses to these cannabinoid ligands are mainly mediated by CB(1) receptors. The non-selective cannabinoid ligands CP 55,940 and WIN 55212-2 are potent agonists and their efficacies in adenylate cyclase and MAPK assays are inhibited by the CB(1) selective antagonist SR141716A (SR1), but not by the CB(2) selective antagonist SR144528 (SR2). The endocannabinoid ligand 2AG, although not active in adenylate cyclase assays, was a potent activator of MAPK signaling in F-11 cells. The analysis of CB(1) and CB(2) receptor gene expression and the characterization of cannabinoid receptor pharmacology in the F-11 cell line demonstrate that it can be used as a tool for interrogating the endogenous signal transduction of cannabinoid receptor subtypes.
Collapse
Affiliation(s)
- Yihong Fan
- Neurological Diseases Research, Global Pharmaceutical Research & Development, Abbott Laboratories, R47W, AP9A, 100 Abbott Park Road, Abbott Park, IL 60064, USA.
| | | | | | | | | | | | | | | |
Collapse
|
19
|
Modeling of ligand binding to G protein coupled receptors: cannabinoid CB1, CB2 and adrenergic β 2 AR. J Mol Model 2011; 17:2353-66. [PMID: 21365223 DOI: 10.1007/s00894-011-0986-7] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2010] [Accepted: 01/24/2011] [Indexed: 10/18/2022]
Abstract
Cannabinoid and adrenergic receptors belong to the class A (similar to rhodopsin) G protein coupled receptors. Docking of agonists and antagonists to CB(1) and CB(2) cannabinoid receptors revealed the importance of a centrally located rotamer toggle switch and its possible participation in the mechanism of agonist/antagonist recognition. The switch is composed of two residues, F3.36 and W6.48, located on opposite transmembrane helices TM3 and TM6 in the central part of the membranous domain of cannabinoid receptors. The CB(1) and CB(2) receptor models were constructed based on the adenosine A(2A) receptor template. The two best scored conformations of each receptor were used for the docking procedure. In all poses (ligand-receptor conformations) characterized by the lowest ligand-receptor intermolecular energy and free energy of binding the ligand type matched the state of the rotamer toggle switch: antagonists maintained an inactive state of the switch, whereas agonists changed it. In case of agonists of β(2)AR, the (R,R) and (S,S) stereoisomers of fenoterol, the molecular dynamics simulations provided evidence of different binding modes while preserving the same average position of ligands in the binding site. The (S,S) isomer was much more labile in the binding site and only one stable hydrogen bond was created. Such dynamical binding modes may also be valid for ligands of cannabinoid receptors because of the hydrophobic nature of their ligand-receptor interactions. However, only very long molecular dynamics simulations could verify the validity of such binding modes and how they affect the process of activation.
Collapse
|
20
|
Mercier RW, Pei Y, Pandarinathan L, Janero DR, Zhang J, Makriyannis A. hCB2 ligand-interaction landscape: cysteine residues critical to biarylpyrazole antagonist binding motif and receptor modulation. ACTA ACUST UNITED AC 2011; 17:1132-42. [PMID: 21035736 DOI: 10.1016/j.chembiol.2010.08.010] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2010] [Revised: 08/09/2010] [Accepted: 08/12/2010] [Indexed: 11/19/2022]
Abstract
The human cannabinoid 2 GPCR (hCB2) is a prime therapeutic target. To define potential cysteine-related binding motifs critical to hCB2-ligand interaction, a library of hCB2 cysteine-substitution mutants and a novel, high-affinity biarylpyrazole hCB2 antagonist/inverse agonist (AM1336) functionalized to serve as a covalent affinity probe to target cysteine residues within (or in the microenvironment of) its hCB2 binding pocket were generated. The data provide direct experimental demonstration that both hCB2 TMH7 cysteines [i.e., C7.38(284) and C7.42(288)] are critical to optimal hCB2-AM1336 binding interaction and AM1336 pharmacological activity in a cell-based functional assay (cAMP formation). Elongating the AM1336 aliphatic side chain generated another novel hCB2 inverse agonist that binds covalently and selectively to C7.42(288) only. Identification of specific cysteine residues critical to hCB2 ligand interaction and function informs the structure-based design of hCB2-targeted medicines.
Collapse
Affiliation(s)
- Richard W Mercier
- School of Pharmacy, University of Connecticut, Storrs, CT 06269, USA
| | | | | | | | | | | |
Collapse
|
21
|
El Bakali J, Muccioli GG, Renault N, Pradal D, Body-Malapel M, Djouina M, Hamtiaux L, Andrzejak V, Desreumaux P, Chavatte P, Lambert DM, Millet R. 4-Oxo-1,4-dihydropyridines as selective CB2 cannabinoid receptor ligands: structural insights into the design of a novel inverse agonist series. J Med Chem 2010; 53:7918-31. [PMID: 20979417 DOI: 10.1021/jm100286k] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Growing evidence shows that CB(2) receptor is an attractive therapeutic target. Starting from a series of 4-oxo-1,4-dihydroquinoline-3-carboxamide as selective CB(2) agonists, we describe here the medicinal chemistry approach leading to the development of CB(2) receptor inverse agonists with a 4-oxo-1,4-dihydropyridine scaffold. The compounds reported here show high affinity and potency at the CB(2) receptor while showing only modest affinity for the centrally expressed CB(1) cannabinoid receptor. Further, we found that the functionality of this series is controlled by its C-6 substituent because agonists bear a methyl or a tert-butyl group and inverse agonists, a phenyl or 4-chlorophenyl group, respectively. Finally, in silico studies suggest that the C-6 substituent could modulate the conformation of W6.48 known to be critical in GPCR activation.
Collapse
Affiliation(s)
- Jamal El Bakali
- Université Lille-Nord de France, Institut de Chimie Pharmaceutique Albert Lespagnol, EA 2692, IFR 114, 3 Rue du Professeur Laguesse, BP 83, 59006 Lille Cedex, France
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
22
|
Diaz P, Phatak SS, Xu J, Fronczek FR, Astruc-Diaz F, Thompson CM, Cavasotto CN, Naguib M. 2,3-Dihydro-1-benzofuran derivatives as a series of potent selective cannabinoid receptor 2 agonists: design, synthesis, and binding mode prediction through ligand-steered modeling. ChemMedChem 2009; 4:1615-29. [PMID: 19637157 DOI: 10.1002/cmdc.200900226] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
We recently discovered and reported a series of N-alkyl-isatin acylhydrazone derivatives that are potent cannabinoid receptor 2 (CB(2)) agonists. In an effort to improve the druglike properties of these compounds and to better understand and improve the treatment of neuropathic pain, we designed and synthesized a new series of 2,3-dihydro-1-benzofuran derivatives bearing an asymmetric carbon atom that behave as potent selective CB(2) agonists. We used a multidisciplinary medicinal chemistry approach with binding mode prediction through ligand-steered modeling. Enantiomer separation and configuration assignment were carried out for the racemic mixture for the most selective compound, MDA7 (compound 18). It appeared that the S enantiomer, compound MDA104 (compound 33), was the active enantiomer. Compounds MDA42 (compound 19) and MDA39 (compound 30) were the most potent at CB(2). MDA42 was tested in a model of neuropathic pain and exhibited activity in the same range as that of MDA7. Preliminary ADMET studies for MDA7 were performed and did not reveal any problems.
Collapse
Affiliation(s)
- Philippe Diaz
- Core Laboratory for Neuromolecular Production, Department of Biomedical and Pharmaceutical Sciences, The University of Montana, 32 Campus Drive, Missoula, MT 59812 (USA)
| | | | | | | | | | | | | | | |
Collapse
|
23
|
Pei Y, Mercier RW, Anday JK, Thakur GA, Zvonok AM, Hurst D, Reggio PH, Janero DR, Makriyannis A. Ligand-binding architecture of human CB2 cannabinoid receptor: evidence for receptor subtype-specific binding motif and modeling GPCR activation. ACTA ACUST UNITED AC 2009; 15:1207-19. [PMID: 19022181 DOI: 10.1016/j.chembiol.2008.10.011] [Citation(s) in RCA: 78] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2008] [Revised: 09/17/2008] [Accepted: 10/02/2008] [Indexed: 11/26/2022]
Abstract
The extensive physiological influence of transmission through the CB2 cannabinoid receptor makes this G protein-coupled receptor (GPCR) a promising therapeutic target for treating neuropathic pain, inflammation, and immune disorders. However, there is little direct structural information pertaining to either GPCR or CB2-receptor ligand recognition and activation. The present work helps characterize experimentally the ligand-binding interactions of the human CB2 (hCB2) receptor. This study illustrates how our overall experimental approach, "ligand-assisted protein structure" (LAPS), affords direct determination of the requirements for ligand binding to the hCB2 receptor and discrimination among the binding motifs for ligands that activate therapeutically relevant GPCRs.
Collapse
Affiliation(s)
- Ying Pei
- School of Pharmacy, University of Connecticut, Storrs, CT 06269, USA
| | | | | | | | | | | | | | | | | |
Collapse
|
24
|
Nebane NM, Hurst DP, Carrasquer CA, Qiao Z, Reggio PH, Song ZH. Residues accessible in the binding-site crevice of transmembrane helix 6 of the CB2 cannabinoid receptor. Biochemistry 2009; 47:13811-21. [PMID: 19053233 DOI: 10.1021/bi8007802] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
We have used the substituted-cysteine accessibility method (SCAM) to map the residues in the sixth membrane-spanning segment of the CB2 cannabinoid receptor that contribute to the surface of the water-accessible binding-site crevice. Using a background of the mutant C2.59S which is relatively insensitive to the methanethiosulfonate (MTS) reagents, we mutated to cysteine, one at a time, 34 consecutive residues in TMH6 of the CB2 receptor. These mutant receptors were then expressed in HEK293 cells. By incubating HEK293 cells stably transfected with CB2 receptors with the small, charged, hydrophilic, thiol-specific reagent methanethiosulfonate ethylammonium (MTSEA), [(3)H]CP55940 binding was significantly inhibited for six mutant receptors. All six of the mutants that reacted with MTSEA were protected from the reaction when pretreated with the cannabinoid agonist WIN55212-2, suggesting that MTSEA modification occurred within the binding crevice. Therefore, the side chains of the residues at these reactive loci (V6.51, L6.52, L6.54, M6.55, L6.59, and T6.62) are on the water-accessible surface of the binding-site crevice. These residues are extracellular to the TMH6 CWXP hinge motif. The pattern of accessibility is consistent with a alpha-helical conformation for this segment of TMH6. Molecular modeling studies performed in the context of the CB2 model show that V6.51, L6.52, L6.54, M6.55, L6.59, and T6.62 face into the CB2 binding pocket, further confirming our SCAM results. These results are similar to the accessibility patterns determined by SCAM studies of TMH6 in the opioid and dopamine D2 receptors.
Collapse
Affiliation(s)
- Ntsang M Nebane
- Department of Pharmacology and Toxicology, University of Louisville School of Medicine, Louisville, Kentucky 40292, USA
| | | | | | | | | | | |
Collapse
|
25
|
Diaz P, Phatak SS, Xu J, Astruc-Diaz F, Cavasotto CN, Naguib M. 6-Methoxy-N-alkyl Isatin Acylhydrazone Derivatives as a Novel Series of Potent Selective Cannabinoid Receptor 2 Inverse Agonists: Design, Synthesis, and Binding Mode Prediction. J Med Chem 2008; 52:433-44. [DOI: 10.1021/jm801353p] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Affiliation(s)
- Philippe Diaz
- Department of Anesthesiology and Pain Medicine, Unit 409, The University of Texas M. D. Anderson Cancer Center, 1400 Holcombe Boulevard, Houston, Texas 77030, School of Health Information Sciences, The University of Texas Health Science Center at Houston, 7000 Fannin, Suite 860B, Houston, Texas 77030
| | - Sharangdhar S. Phatak
- Department of Anesthesiology and Pain Medicine, Unit 409, The University of Texas M. D. Anderson Cancer Center, 1400 Holcombe Boulevard, Houston, Texas 77030, School of Health Information Sciences, The University of Texas Health Science Center at Houston, 7000 Fannin, Suite 860B, Houston, Texas 77030
| | - Jijun Xu
- Department of Anesthesiology and Pain Medicine, Unit 409, The University of Texas M. D. Anderson Cancer Center, 1400 Holcombe Boulevard, Houston, Texas 77030, School of Health Information Sciences, The University of Texas Health Science Center at Houston, 7000 Fannin, Suite 860B, Houston, Texas 77030
| | - Fanny Astruc-Diaz
- Department of Anesthesiology and Pain Medicine, Unit 409, The University of Texas M. D. Anderson Cancer Center, 1400 Holcombe Boulevard, Houston, Texas 77030, School of Health Information Sciences, The University of Texas Health Science Center at Houston, 7000 Fannin, Suite 860B, Houston, Texas 77030
| | - Claudio N. Cavasotto
- Department of Anesthesiology and Pain Medicine, Unit 409, The University of Texas M. D. Anderson Cancer Center, 1400 Holcombe Boulevard, Houston, Texas 77030, School of Health Information Sciences, The University of Texas Health Science Center at Houston, 7000 Fannin, Suite 860B, Houston, Texas 77030
| | - Mohamed Naguib
- Department of Anesthesiology and Pain Medicine, Unit 409, The University of Texas M. D. Anderson Cancer Center, 1400 Holcombe Boulevard, Houston, Texas 77030, School of Health Information Sciences, The University of Texas Health Science Center at Houston, 7000 Fannin, Suite 860B, Houston, Texas 77030
| |
Collapse
|
26
|
Zhang Y, Burgess JP, Brackeen M, Gilliam A, Mascarella SW, Page K, Seltzman HH, Thomas BF. Conformationally constrained analogues of N-(piperidinyl)-5-(4-chlorophenyl)-1-(2,4- dichlorophenyl)-4-methyl-1H-pyrazole-3-carboxamide (SR141716): design, synthesis, computational analysis, and biological evaluations. J Med Chem 2008; 51:3526-39. [PMID: 18512901 DOI: 10.1021/jm8000778] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Structure-activity relationships (SARs) of 1 (SR141716) have been extensively documented, however, the conformational properties of this class have received less attention. In an attempt to better understand ligand conformations optimal for receptor recognition, we have designed and synthesized a number of derivatives of 1, including a four-carbon-bridged molecule (11), to constrain rotation of the diaryl rings. Computational analysis of 11 indicates approximately 20 kcal/mol energy barrier for rotation of the two aryl rings. NMR studies have determined the energy barrier to be approximately 18 kcal/mol and suggested atropisomers could exist. Receptor binding and functional studies with these compounds displayed reduced affinity and potency when compared to 1. This indicates that our structural modifications either constrain the ring systems in a suboptimal orientation for receptor interaction or the introduction of steric bulk leads to disfavored steric interactions with the receptor, and/or the relatively modest alterations in the molecular electrostatic potentials results in disfavored Coulombic interactions.
Collapse
Affiliation(s)
- Yanan Zhang
- Chemistry and Life Sciences, Research Triangle Institute, Research Triangle Park, NC 27709, USA.
| | | | | | | | | | | | | | | |
Collapse
|
27
|
Padgett LW, Howlett AC, Shim JY. Binding mode prediction of conformationally restricted anandamide analogs within the CB1 receptor. J Mol Signal 2008; 3:5. [PMID: 18302793 PMCID: PMC2289822 DOI: 10.1186/1750-2187-3-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2007] [Accepted: 02/26/2008] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND CB1 cannabinoid receptors are G-protein coupled receptors for endocannabinoids including anandamide and 2-arachidonoylglycerol. Because these arachidonic acid metabolites possess a 20-carbon polyene chain as the alkyl terminal moiety, they are highly flexible with the potential to adopt multiple biologically relevant conformations, particularly those in a bent form. To better understand the molecular interactions associated with binding and steric trigger mechanisms of receptor activation, a series of conformationally-restricted anandamide analogs having a wide range of affinity and efficacy were evaluated. RESULTS A CB1 receptor model was constructed to include the extracellular loops, particularly extracellular loop 2 which possesses an internal disulfide linkage. Using both Glide (Schrödinger) and Affinity (Accelrys) docking programs, binding conformations of six anandamide analogs were identified that conform to rules applicable to the potent, efficacious and stereoselective non-classical cannabinoid CP55244. Calculated binding energies of the optimum structures from both procedures correlated well with the reported binding affinity values. The most potent and efficacious of the ligands adopted conformations characterized by interactions with both the helix-3 lysine and hydrophobic residues that interact with CP55244. The other five compounds formed fewer or less energetically favorable interactions with these critical residues. The flexibility of the tested anandamide analogs, measured by torsion angles around the benzene as well as the stretch between side chain moieties, could contribute to the differences in ability to interact with the CB1 receptor. CONCLUSION Analyses of multiple poses of conformationally-restricted anandamide analogs permitted identification of favored amino acid interactions within the CB1 receptor binding pocket. A ligand possessing both high affinity and cannabinoid agonist efficacy was able to interact with both polar and hydrophobic interaction sites utilized by the potent and efficacious non-classical cannabinoid CP55940. In contrast, other analogs characterized by reduced affinity or efficacy exhibited less favorable interactions with those key residues.
Collapse
Affiliation(s)
- Lea W Padgett
- Neuroscience of Drug Abuse Research Program, Julius L, Chambers Biomedical/Biotechnology Research Institute, North Carolina Central University, Durham, NC 27707, USA.
| | | | | |
Collapse
|
28
|
Targeting the cannabinoid CB2 receptor: modelling and structural determinants of CB2 selective ligands. Br J Pharmacol 2007; 153:335-46. [PMID: 17982473 DOI: 10.1038/sj.bjp.0707567] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Recent developments indicate that CB2 receptor ligands have the potential to become therapeutically important. To explore this potential, it is necessary to develop compounds with high affinity for the CB2 receptor and little affinity for the CB1 receptor. This review will discuss structure-activity relations at both receptors for classical cannabinoids and cannabimimetic indoles. Examples of CB2 selective ligands from both classes of compounds are presented and the structural features leading to selectivity are described. Two approaches, receptor mutations and molecular modelling, have been employed to investigate the interaction of ligands with both cannabinoid receptors. These results obtained from these techniques are discussed.
Collapse
|
29
|
Chen JZ, Wang J, Xie XQ. GPCR structure-based virtual screening approach for CB2 antagonist search. J Chem Inf Model 2007; 47:1626-37. [PMID: 17580929 DOI: 10.1021/ci7000814] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The potential for therapeutic specificity in regulating diseases has made cannabinoid (CB) receptors one of the most important G-protein-coupled receptor (GPCR) targets in search for new drugs. Considering the lack of related 3D experimental structures, we have established a structure-based virtual screening protocol to search for CB2 bioactive antagonists based on the 3D CB2 homology structure model. However, the existing homology-predicted 3D models often deviate from the native structure and therefore may incorrectly bias the in silico design. To overcome this problem, we have developed a 3D testing database query algorithm to examine the constructed 3D CB2 receptor structure model as well as the predicted binding pocket. In the present study, an antagonist-bound CB2 receptor complex model was initially generated using flexible docking simulation and then further optimized by molecular dynamic and mechanical (MD/MM) calculations. The refined 3D structural model of the CB2-ligand complex was then inspected by exploring the interactions between the receptor and ligands in order to predict the potential CB2 binding pocket for its antagonist. The ligand-receptor complex model and the predicted antagonist binding pockets were further processed and validated by FlexX-Pharm docking against a testing compound database that contains known antagonists. Furthermore, a consensus scoring (CScore) function algorithm was established to rank the binding interaction modes of a ligand on the CB2 receptor. Our results indicated that the known antagonists seeded in the testing database can be distinguished from a significant amount of randomly chosen molecules. Our studies demonstrated that the established GPCR structure-based virtual screening approach provided a new strategy with a high potential for in silico identifying novel CB2 antagonist leads based on the homology-generated 3D CB2 structure model.
Collapse
Affiliation(s)
- Jian-Zhong Chen
- Department of Pharmaceutical Sciences, School of Pharmacy, Pittsburgh Molecular Library Screening Center, Drug Discovery Institute, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, USA
| | | | | |
Collapse
|
30
|
Petitet F, Donlan M, Michel A. GPR55 as a new cannabinoid receptor: still a long way to prove it. Chem Biol Drug Des 2007; 67:252-3. [PMID: 16611220 DOI: 10.1111/j.1747-0285.2006.00370.x] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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
Collapse
|
31
|
Surgand JS, Rodrigo J, Kellenberger E, Rognan D. A chemogenomic analysis of the transmembrane binding cavity of human G-protein-coupled receptors. Proteins 2006; 62:509-38. [PMID: 16294340 DOI: 10.1002/prot.20768] [Citation(s) in RCA: 189] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
The amino acid sequences of 369 human nonolfactory G-protein-coupled receptors (GPCRs) have been aligned at the seven transmembrane domain (TM) and used to extract the nature of 30 critical residues supposed--from the X-ray structure of bovine rhodopsin bound to retinal--to line the TM binding cavity of ground-state receptors. Interestingly, the clustering of human GPCRs from these 30 residues mirrors the recently described phylogenetic tree of full-sequence human GPCRs (Fredriksson et al., Mol Pharmacol 2003;63:1256-1272) with few exceptions. A TM cavity could be found for all investigated GPCRs with physicochemical properties matching that of their cognate ligands. The current approach allows a very fast comparison of most human GPCRs from the focused perspective of the predicted TM cavity and permits to easily detect key residues that drive ligand selectivity or promiscuity.
Collapse
|
32
|
Tuccinardi T, Ferrarini PL, Manera C, Ortore G, Saccomanni G, Martinelli A. Cannabinoid CB2/CB1 selectivity. Receptor modeling and automated docking analysis. J Med Chem 2006; 49:984-94. [PMID: 16451064 DOI: 10.1021/jm050875u] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Three-dimensional models of the CB1 and CB2 cannabinoid receptors were constructed by means of a molecular modeling procedure, using the X-ray structure of bovine rhodopsin as the initial template, and taking into account the available site-directed mutagenesis data. The cannabinoid system was studied by means of docking techniques. An analysis of the interaction of WIN55212-2 with both receptors showed that CB2/CB1 selectivity is mainly determined by the interaction in the CB2 with the nonconserved residues S3.31 and F5.46, whose importance was suggested by site-directed mutagenesis data. We also carried out an automated docking of several ligands into the CB2 model, using the AUTODOCK 3.0 program; the good correlation obtained between the estimated free energy binding and the experimental binding data confirmed our binding hypothesis and the reliability of the model.
Collapse
Affiliation(s)
- Tiziano Tuccinardi
- Dipartimento di Scienze Farmaceutiche, Università di Pisa, via Bonanno 6, 56126 Pisa, Italy
| | | | | | | | | | | |
Collapse
|
33
|
Raduner S, Majewska A, Chen JZ, Xie XQ, Hamon J, Faller B, Altmann KH, Gertsch J. Alkylamides from Echinacea are a new class of cannabinomimetics. Cannabinoid type 2 receptor-dependent and -independent immunomodulatory effects. J Biol Chem 2006; 281:14192-206. [PMID: 16547349 DOI: 10.1074/jbc.m601074200] [Citation(s) in RCA: 183] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Alkylamides (alkamides) from Echinacea modulate tumor necrosis factor alpha mRNA expression in human monocytes/macrophages via the cannabinoid type 2 (CB2) receptor (Gertsch, J., Schoop, R., Kuenzle, U., and Suter, A. (2004) FEBS Lett. 577, 563-569). Here we show that the alkylamides dodeca-2E,4E,8Z,10Z-tetraenoic acid isobutylamide (A1) and dodeca-2E,4E-dienoic acid isobutylamide (A2) bind to the CB2 receptor more strongly than the endogenous cannabinoids. The Ki values of A1 and A2 (CB2 approximately 60 nM; CB1 >1500 nM) were determined by displacement of the synthetic high affinity cannabinoid ligand [3H]CP-55,940. Molecular modeling suggests that alkylamides bind in the solvent-accessible cavity in CB2, directed by H-bonding and pi-pi interactions. In a screen with 49 other pharmacologically relevant receptors, it could be shown that A1 and A2 specifically bind to CB2 and CB1. A1 and A2 elevated total intracellular Ca2+ in CB2-positive but not in CB2-negative promyelocytic HL60 cells, an effect that was inhibited by the CB2 antagonist SR144528. At 50 nM, A1, A2, and the endogenous cannabinoid anandamide (CB2 Ki >200 nM) up-regulated constitutive interleukin (IL)-6 expression in human whole blood in a seemingly CB2-dependent manner. A1, A2, anandamide, the CB2 antagonist SR144528 (Ki <10 nM), and also the non-CB2-binding alkylamide undeca-2E-ene,8,10-diynoic acid isobutylamide all significantly inhibited lipopolysaccharide-induced tumor necrosis factor alpha, IL-1beta, and IL-12p70 expression (5-500 nM) in a CB2-independent manner. Alkylamides and anandamide also showed weak differential effects on anti-CD3-versus anti-CD28-stimulated cytokine expression in human whole blood. Overall, alkylamides, anandamide, and SR144528 potently inhibited lipopolysaccharide-induced inflammation in human whole blood and exerted modulatory effects on cytokine expression, but these effects are not exclusively related to CB2 binding.
Collapse
Affiliation(s)
- Stefan Raduner
- Department of Chemistry and Applied Biosciences, ETH Zurich, Wolfgang-Pauli-Strasse 10, CH-8093 Zürich, Switzerland
| | | | | | | | | | | | | | | |
Collapse
|
34
|
Chen JZ, Han XW, Liu Q, Makriyannis A, Wang J, Xie XQ. 3D-QSAR Studies of Arylpyrazole Antagonists of Cannabinoid Receptor Subtypes CB1 and CB2. A Combined NMR and CoMFA Approach. J Med Chem 2005; 49:625-36. [PMID: 16420048 DOI: 10.1021/jm050655g] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The present work focuses on the study of the three-dimensional (3D) structural requirements for selective antagonist activity of arylpyrazole compounds at the cannabinoid CB1 and CB2 receptors. Initially, a combined high-resolution two-dimensional (2D) NMR and computer modeling approach was carried out to study the solution structure of the key pyrazole derivative N-(piperidin-1-yl)-5-phenyl-1-(n-pentyl)-4-methyl-1H-pyrazole-3-carboxamide (AM263). By using the NMR-determined molecular conformers as templates, the 3D quantitative structure-activity relationship (QSAR) studies were performed with the comparative molecular field analysis (CoMFA) approach on a set of arylpyrazole cannabinoid receptor antagonists. Molecular alignments suitable for deriving valuable pharmacophoric features for this series of compounds were determined. Such systematic 3D-QSAR/CoMFA analyses of 29 molecules and their receptor affinities gave guidance for understanding the binding affinities of arylpyrazoles at the CB1 and CB2 binding sites, respectively. Comparison of CoMFA steric and potential contour maps for affinity at the two cannabinoid receptor subtypes helps to differentiate structural requirements for each subtype and serves as a basis for the design of later-generation analogues.
Collapse
Affiliation(s)
- Jian-Zhong Chen
- Department of Pharmaceutical & Pharmacological Sciences, College of Pharmacy, University of Houston, Texas 77204-5037, USA
| | | | | | | | | | | |
Collapse
|
35
|
Abstract
To date, two cannabinoid receptors have been isolated by molecular cloning. The CB1 and CB2 cannabinoid receptors are members of the G protein-coupled receptor family. There is also evidence for additional cannabinoid receptor subtypes. The CB1 and CB2 receptors recognize endogenous and exogenous cannabinoid compounds, which fall into five structurally diverse classes. Mutagenesis and molecular modeling studies have identified several key amino acid residues involved in the selective recognition of these ligands. Numerous residues involved in receptor activation have been elucidated. Regions of the CB1 receptor mediating desensitization and internalization have also been discovered. The known genetic structures of the CB1 and CB2 receptors indicate polymorphisms and multiple exons that maybe involved in tissue and species-specific regulation of these genes. The cannabinoid receptors are regulated during chronic agonist exposure, and gene expression is altered in disease states. There is a complex molecular architecture of the cannabinoid receptors that allows a single receptor to recognize multiple classes of compounds and produce an array of distinct downstream effects.
Collapse
MESH Headings
- Amino Acid Sequence
- Animals
- Binding Sites
- Drug Tolerance
- Humans
- Molecular Sequence Data
- Polymorphism, Genetic
- Protein Conformation
- Receptor, Cannabinoid, CB1/chemistry
- Receptor, Cannabinoid, CB1/genetics
- Receptor, Cannabinoid, CB1/physiology
- Receptor, Cannabinoid, CB2/chemistry
- Receptor, Cannabinoid, CB2/genetics
- Receptor, Cannabinoid, CB2/physiology
Collapse
Affiliation(s)
- M E Abood
- Forbes Norris MDA/ALS Research, California Pacific Medical Center, 2351 Clay St 416, San Francisco, CA 94115, USA.
| |
Collapse
|
36
|
Yates AS, Doughty SW, Kendall DA, Kellam B. Chemical modification of the naphthoyl 3-position of JWH-015: in search of a fluorescent probe to the cannabinoid CB2 receptor. Bioorg Med Chem Lett 2005; 15:3758-62. [PMID: 15993070 DOI: 10.1016/j.bmcl.2005.05.049] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2005] [Revised: 05/12/2005] [Accepted: 05/17/2005] [Indexed: 11/29/2022]
Abstract
In silico modelling was used to guide the positioning of the fluorescent dye NBD-F on the cannabinoid CB2 receptor agonist JWH-015. While the ultimate fluorescent conjugate lost extensive binding affinity to the cannabinoid CB2 receptor, affinity and efficacy studies on the naphthoyl 3-position modified precursor molecules have provided new insight into structure-activity relationships associated with this position.
Collapse
Affiliation(s)
- Andrew S Yates
- School of Pharmacy, Centre for Biomolecular Sciences, University of Nottingham, University Park, Nottingham NG7 2RD, UK
| | | | | | | |
Collapse
|
37
|
Fay JF, Dunham TD, Farrens DL. Cysteine residues in the human cannabinoid receptor: only C257 and C264 are required for a functional receptor, and steric bulk at C386 impairs antagonist SR141716A binding. Biochemistry 2005; 44:8757-69. [PMID: 15952782 DOI: 10.1021/bi0472651] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The human neuronal cannabinoid receptor (CB1) is a G-protein-coupled receptor (GPCR) triggered by the psychoactive ingredients in marijuana, as well as endogenous cannabinoids produced in the brain. As with most GPCRs, the mechanism of CB1 activation is poorly understood. In this work, we have assessed the role of cysteine residues in CB1 ligand binding and activation, and demonstrate a method for mapping key determinants in CB1 structure and function. Through mutational analysis, we find that only two cysteines, C257 and C264, are required for high-level expression and receptor function. In addition, through cysteine reactivity studies, we find that a cysteine in transmembrane helix seven, C386 (C7.42), is reactive toward methanethiosulfonate (MTS) sulfhydryl labeling agents, and is thus solvent accessible. Interestingly, steric bulk introduced at this site, either through MTS labeling or by mutation, inhibits binding of the antagonist drug SR141716A (also known as Rimonabant or Accomplia), but does not affect the binding of the agonist CP55940. Our subsequent modeling studies suggest this effect is caused by steric clash of the modified C386 residue with the piperidine ring of SR141716A and/or disruption of an aromatic microdomain in the binding pocket. On the basis of these results, we hypothesize that bound SR141716A inhibits the ability of transmembrane helix 6 to move during formation of the functionally active receptor state.
Collapse
Affiliation(s)
- Jonathan F Fay
- Department of Biochemistry and Molecular Biology, Oregon Health and Science University, Portland, Oregon 97239-3098, USA
| | | | | |
Collapse
|
38
|
Zhang R, Hurst DP, Barnett-Norris J, Reggio PH, Song ZH. Cysteine 2.59(89) in the Second Transmembrane Domain of Human CB2 Receptor Is Accessible within the Ligand Binding Crevice: Evidence for Possible CB2 Deviation from a Rhodopsin Template. Mol Pharmacol 2005; 68:69-83. [PMID: 15840841 DOI: 10.1124/mol.104.007823] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
In this study, the sensitivity of the CB2 receptor to methanethiosulfonate (MTS) derivatives was tested, and a native cysteine residue conferring the sensitivity was identified. By incubating human embryonic kidney 293 cells stably transfected with CB2 receptors and MTS derivatives such as MTS ethylammonium (MTSEA), [(3)H]HU-243 binding was inhibited. Pretreatment of the CB2 receptor with cannabinoid ligands prevented this inhibition, suggesting that MTSEA modification occurred within the binding crevice. To identify the cysteine(s) responsible for the MTSEA sensitivity, 10 CB2 mutants were prepared in which the eight cysteines in transmembrane domains or extracellular loop 2 were mutated to serine or alanine, one at a time or in combination. Five mutants exhibited specific [(3)H]HU-243 binding, with K(d) and B(max) values similar to those of wild-type CB2. However, five other mutants had no detectable ligand binding and were not detected on cell membranes by Western blot analysis. Among the five mutants with normal binding, only the sensitivity to MTSEA of the C2.59(89)S mutant was reduced significantly. These data demonstrate that C2.59(89) is the residue that mainly confers the inhibitory effect of MTSEA on ligand binding. Furthermore, the magnitude of the second-order rate constant (1.14 +/- 0.28 M(-1)s(-1)) for the MTSEA reaction with wild-type CB2 suggests that C2.59(89) resides at the margin of the CB2 binding site crevice. The accessibility of C2.59(89) to MTSEA provides experimental evidence for a possible conformational difference between TMH2 of CB2 versus Rho. Modeling studies undertaken to explore the origin of such differences suggest it is possibly caused by the conformational influence of S2.54(84).
Collapse
Affiliation(s)
- Rundong Zhang
- Department of Pharmacology and Toxicology, University of Louisville School of Medicine, Louisville, KY 40292, USA
| | | | | | | | | |
Collapse
|
39
|
Montero C, Campillo NE, Goya P, Páez JA. Homology models of the cannabinoid CB1 and CB2 receptors. A docking analysis study. Eur J Med Chem 2005; 40:75-83. [PMID: 15642412 DOI: 10.1016/j.ejmech.2004.10.002] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2003] [Revised: 07/15/2004] [Accepted: 10/05/2004] [Indexed: 11/25/2022]
Abstract
The 3D models of both CB1 and CB2 human receptors have been established by homology modeling using as template the X-ray structure of bovine Rhodopsin (code pdb: 1F88) a G-protein-coupled receptor (GPCR). A recursive approach comprising sequence alignment and model building was used to build both models, followed by the refinement of non-conserved regions. The cannabinoid system has been studied by means of docking techniques, using the 3D models of both CB1 and CB2 and well known reference inverse agonist/antagonist compounds. An approach based on the flexibility of the structures has been used to model the receptor-ligand complexes. The structural effects of ligand binding were studied and analyzed on the basis of hydrogen bond interactions, and binding energy calculations. Potential interaction sites of the receptor were determined from analysis of the difference accessible surface area (DASA) study of the protein with and without ligand.
Collapse
MESH Headings
- Computer Simulation
- Hydrogen Bonding
- Ligands
- Models, Molecular
- Protein Binding
- Protein Conformation/drug effects
- Receptor, Cannabinoid, CB1/antagonists & inhibitors
- Receptor, Cannabinoid, CB1/chemistry
- Receptor, Cannabinoid, CB2/antagonists & inhibitors
- Receptor, Cannabinoid, CB2/chemistry
- Sequence Alignment
- Sequence Homology, Amino Acid
Collapse
Affiliation(s)
- Cristina Montero
- Instituto de Química Médica (CSIC), Juan de la Cierva 3, 28006 Madrid, Spain
| | | | | | | |
Collapse
|
40
|
Xie XQ, Chen JZ. NMR structural comparison of the cytoplasmic juxtamembrane domains of G-protein-coupled CB1 and CB2 receptors in membrane mimetic dodecylphosphocholine micelles. J Biol Chem 2004; 280:3605-12. [PMID: 15550382 DOI: 10.1074/jbc.m410294200] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The fourth cytoplasmic domain, the so-called C-terminal juxtamembrane segment or helix VIII, has been identified in numerous G-protein-coupled receptors and exhibits unique functional characteristics. Efforts have been devoted to studying the juxtamembrane segment in order to understand the biological importance of the segment in G-protein activation of the cannabinoid CB1 and CB2 receptors. Recent biochemical data revealed that the CB1 C-terminal juxtamembrane peptide fragment CB1-(401-417) can directly activate the G-protein and also showed that the specificity of the signal transduction activation by the C-terminal juxtamembrane region is unique to the CB1 receptor but not to the CB2 receptor (Mukhopadhyay, S., and Howlett, A. C. (2001) Eur. J. Biochem. 268, 499-505). However, there is experimental work, not yet reported, on the conformational analyses and structural comparison between the respective helix VIII segments of the two receptors. In the present study, we have examined the conformational specificities of the cytoplasmic helical domains for both cannabinoid receptors. Three-dimensional structural features of two synthetic CB1 and CB2 peptides, CB1I397-G418 and CB2I298-K319, respectively, in membrane mimetic DPC micelles were studied using a combined high resolution NMR and computer modeling approach. Comparisons of the NMR-determined structures of the two peptides as well as their correspondent mutant peptides revealed their conformational properties and salt bridge dissimilarity, which might help us to understand the different structural roles of the fourth cytoplasmic helices in the function and regulation of CB1 and CB2 receptors.
Collapse
Affiliation(s)
- Xiang-Qun Xie
- Department of Pharmacological and Pharmaceutical Sciences, College of Pharmacy, University of Houston, Houston, Texas 77204-5037, USA.
| | | |
Collapse
|
41
|
Salo OMH, Lahtela-Kakkonen M, Gynther J, Järvinen T, Poso A. Development of a 3D model for the human cannabinoid CB1 receptor. J Med Chem 2004; 47:3048-57. [PMID: 15163186 DOI: 10.1021/jm031052c] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A novel comparison model of the human cannabinoid CB1 receptor has been constructed using the bovine rhodopsin X-ray structure as a template. The model was subjected to a 500-ps molecular dynamics simulation, and thereafter new conformers of the receptor model were produced in a simulated annealing procedure. Using an automated docking procedure, well-known cannabimimetic ligands were docked into six different model conformers, of which one was chosen for a detailed study of receptor-ligand interactions. The docking results confirm, for example, the importance of lysine K3.28(192) in the binding of these ligands. Also, other experimental data are fairly consistent with the present model, though there are some differences when compared to other recent CB1 comparison models. The present model will serve as a tool to investigate the receptor-ligand interactions and facilitate the design of novel cannabimimetic drugs.
Collapse
Affiliation(s)
- Outi M H Salo
- Department of Pharmaceutical Chemistry, University of Kuopio, P.O. Box 1627, FIN-70211 Kuopio, Finland.
| | | | | | | | | |
Collapse
|
42
|
McPartland JM. Phylogenomic and chemotaxonomic analysis of the endocannabinoid system. ACTA ACUST UNITED AC 2004; 45:18-29. [PMID: 15063097 DOI: 10.1016/j.brainresrev.2003.11.005] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/04/2003] [Indexed: 11/25/2022]
Abstract
The endocannabinoid system consists of two cannabinoid (CB) receptors, seven ligands, and ligand-catabolizing enzymes such as fatty acid amid hydrolase (FAAH) and monoglyceride lipase (MGL). The system's phylogenetic distribution is poorly known. The ligands cannot be molecularly investigated because they are not polypeptides and their specific synthetic enzymes have not been identified, so no sequences are available. Ligand phylogenetics can be inferred, nonetheless, by their presence in a range of extant organisms. Thus a meta-analysis of ligand extraction studies was performed (chemotaxonomy), and compared to a molecular search for homologs of CB receptors, vanilloid receptors (VR1), FAAH, and MGL in the genomes of sequenced organisms (phylogenomics). Putative homologs underwent functional mapping to ascertain the presence of critical amino acid motifs known to impart protein functionality. From an evolutionary perspective it appears that (1) endocannabinoid ligands evolved before CB receptors; (2) the ligands evolved independently multiple times; (3) CB receptors evolved prior to the metazoan-bilaterian divergence (ie, between extant Hydra and leech), but were secondarily lost in the Ecdysozoa; (4) VR1 may predate CB receptors but its affinity for endocannabinoids is a recent acquisition, appearing after the lower vertebrate-mammal divergence; (5) MGL may be as old as the ligands, whereas FAAH evolved recently, after the appearance of vertebrates. FAAH's emergence correlates with VR1's newly-found affinity for anandamide; this overlap in evolutionary time is recapitulated by complementary distribution patterns of FAAH, VR1, and anandamide in the brain. Linking FAAH, VR1, and anandamide implies a coupling among the remaining "older" parts of the endocannabinoid system, MGL, CB receptors, and 2-AG.
Collapse
Affiliation(s)
- John M McPartland
- GW Pharmaceuticals Ltd., Porton Down Science Park, Salisbury, Wiltshire SP4 0JQ, UK.
| |
Collapse
|
43
|
Xie XQ, Chen JZ, Billings EM. 3D structural model of the G-protein-coupled cannabinoid CB2 receptor. Proteins 2003; 53:307-19. [PMID: 14517981 DOI: 10.1002/prot.10511] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The potential for therapeutic specificity in regulating diseases and for reduced side effects has made cannabinoid (CB) receptors one of the most important G-protein-coupled receptor (GPCR) targets for drug discovery. The cannabinoid (CB) receptor subtype CB2 is of particular interest due to its involvement in signal transduction in the immune system and its increased characterization by mutational and other studies. However, our understanding of their mode of action has been limited by the absence of an experimental receptor structure. In this study, we have developed a 3D model of the CB2 receptor based on the recent crystal structure of a related GPCR, bovine rhodopsin. The model was developed using multiple sequence alignment of homologous receptor sub-types in humans and mammals, and compared with other GPCRs. Alignments were analyzed with mutation scores, pairwise hydrophobicity profiles and Kyte-Doolittle plots. The 3D model of the transmembrane segment was generated by mapping the CB2 sequence onto the homologous residues of the rhodopsin structure. The extra- and intracellular loop regions of the CB2 were generated by searching for homologous C(alpha) backbone sequences in published structures in the Brookhaven Protein Databank (PDB). Residue side chains were positioned through a combination of rotamer library searches, simulated annealing and minimization. Intermediate models of the 7TM helix bundles were analyzed in terms of helix tilt angles, hydrogen-bond networks, conserved residues and motifs, possible disulfide bonds. The amphipathic cytoplasmic helix domain was also correlated with biological and site-directed mutagenesis data. Finally, the model receptor-binding cavity was characterized using solvent-accessible surface approach.
Collapse
Affiliation(s)
- Xiang-Qun Xie
- Institute of Materials Science, and Department of Pharmaceutical Science, School of Pharmacy, University of Connecticut, Storrs, Connecticut 06269-3136, USA
| | | | | |
Collapse
|
44
|
McPartland JM, Glass M. Functional mapping of cannabinoid receptor homologs in mammals, other vertebrates, and invertebrates. Gene 2003; 312:297-303. [PMID: 12909367 DOI: 10.1016/s0378-1119(03)00638-3] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Over the past decade, several putative homologs of cannabinoid receptors (CBRs) have been identified by homology screening. Homology screening utilizes sequence alignment search engines to recognize homologs. We investigated these putative CBR homologs further by 'functional mapping' of their deduced amino acid sequences. The entire pharmacophore of a CBR has not yet been elucidated, but point-mutation studies have identified over 20 amino acid residues that impart CBR specificity for ligand recognition and/or signal transduction. Twenty point-mutation studies were used to construct a CBR functionality matrix. Sixteen putative CBR homologs were then mapped over the matrix. Several putative homologs did not hold up to this analysis: human GPR3, GPR6, GPR12, and Caenorhabditis elegans C02H7.2 expressed a series of crippling substitutions in the matrix, strongly suggesting they do not encode functional CBRs. Mapping the contested leech (Hirudo medicinalis) CBR sequence suggests that it encodes a functional CB1; it expresses fewer substitutions than the sea squirt (Ciona intestinalis) CB1 sequence. Mapping a putative CB2 ortholog in the puffer fish (Fugu rubripes T012234) suggests it may encode a CBR other than CB2. These findings are consistent with the lack of experimental data proving these putative CBRs have affinity for cannabinoid ligands. Matrix analysis also reveals that SR144528, a 'CB2-specific' synthetic antagonist, has affinity for non-mammalian CB1 receptors, and that L3.45 appears to be CB2-specific, its cognate in CB1 receptors is F3.45. In conclusion, functional mapping, utilizing point-mutation studies, may improve the specificity of homology screening performed by sequence alignment search engines.
Collapse
Affiliation(s)
- John M McPartland
- GW Pharmaceuticals, Porton Down Science Park, Salisbury, Wiltshire SP4 0JQ, UK.
| | | |
Collapse
|
45
|
Murphy JW, Kendall DA. Integrity of extracellular loop 1 of the human cannabinoid receptor 1 is critical for high-affinity binding of the ligand CP 55,940 but not SR 141716A. Biochem Pharmacol 2003; 65:1623-31. [PMID: 12754098 DOI: 10.1016/s0006-2952(03)00155-2] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Like other G-protein coupled receptors with hydrophobic ligands, the human cannabinoid receptor 1 (CB1) is thought to bind its ligands within the transmembrane region of the receptor. However, for some of these receptors the extracellular loops (ECs) have also been shown to play a role in ligand recognition and selectivity. We have taken a mutagenesis approach to examine the role of the amino terminus, EC1, and EC3 of CB1 in ligand binding. Eight mutant receptors, each with a dipeptide insertion, were constructed, expressed, and evaluated for binding to the cannabinoid ligands (-)-cis-3[2-hydroxy-4-(1',1'-dimethylheptyl)phenyl]-trans-4-(3-hydroxypropyl)cyclohexanol (CP 55,940) and N-(piperidin-1-yl)-5-(4-chlorophenyl)-1-(2,4-dichlorophenyl)-4-methyl-1H-pyrazole-3-carboxamide hydrochloride (SR 141716A). Mutants with insertions in the membrane distal region of the amino terminus or EC3 maintained affinity for both ligands. Those with insertions in the membrane proximal region of the amino terminus or EC1 exhibited a loss of affinity for CP 55,940 while retaining wild-type affinity for SR 141716A. Representative mutants were analyzed for agonist-induced inhibition of cyclic AMP accumulation, and the results indicated that G-protein coupling remained intact. Alanine substitution mutants were made to address whether it was the perturbation of the overall structure of the region or the displacement of particular side chains that was responsible for the loss of CP 55,940 binding. We conclude that a structurally intact EC1, but not the comparably short EC3, is essential for high-affinity CP 55,940 binding.
Collapse
Affiliation(s)
- James W Murphy
- Department of Molecular and Cell Biology, University of Connecticut, 75 N. Eagleville Road, Storrs, CT 06269-3044, USA
| | | |
Collapse
|
46
|
McAllister SD, Tao Q, Barnett-Norris J, Buehner K, Hurst DP, Guarnieri F, Reggio PH, Nowell Harmon KW, Cabral GA, Abood ME. A critical role for a tyrosine residue in the cannabinoid receptors for ligand recognition. Biochem Pharmacol 2002; 63:2121-36. [PMID: 12110371 DOI: 10.1016/s0006-2952(02)01031-6] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Previous mutation and modeling studies have identified an aromatic cluster in the transmembrane helix (TMH) 3-4-5 region as important for ligand binding at the CB(1) and CB(2) cannabinoid receptors. Through novel mixed mode Monte Carlo/Stochastic Dynamics (MC/SD) calculations, we tested the importance of aromaticity at position 5.39(275) in CB(1). MC/SD calculations were performed on wild-type (WT) CB(1) and two mutants, Y5.39(275)F and Y5.39(275)I. Results indicated that while the CB(1) Y5.39(275)F mutant is very similar to WT, the Y5.39(275)I mutant shows pronounced topology changes in the TMH 3-4-5 region. Site-directed mutagenesis studies of tyrosine 5.39 to phenylalanine (Y-->F) or isoleucine (Y-->I) in both CB(1) and CB(2) were performed to determine the functional role of this amino acid in each receptor subtype. HEK 293 cells transfected with mutant receptor cDNAs were evaluated in radioligand binding and cyclic AMP assays. The CB(1) mutant and WT receptors were also co-expressed with G-protein-coupled inwardly rectifying channels (GIRK1 and GIRK4) in Xenopus oocytes to assess functional coupling. The Y-->F mutation resulted in cannnabinoid receptors with subtle differences in WT binding and signal transduction. In contrast, the Y-->I mutations produced receptors that could not produce signal transduction or bind to multiple cannabinoid compounds. However, immunofluorescence data indicate that the Y-->I mutation was compartmentalized and expressed at a level similar to that of the WT cannabinoid receptor. These results underscore the importance of aromaticity at position CB(1) 5.39(275) and CB(2) 5.39(191) for ligand recognition in the cannabinoid receptors.
Collapse
Affiliation(s)
- Sean D McAllister
- Forbes Norris ALS/MDA Research Center, California Pacific Medical Center, San Francisco, CA 94115, USA
| | | | | | | | | | | | | | | | | | | |
Collapse
|
47
|
Abstract
During the last decade, research on the molecular biology and genetics of cannabinoid receptors has led to a remarkable progress in understanding of the endogenous cannabinoid system, which functions in a plethora of physiological processes in the animal. At present, two types of cannabinoid receptors have been cloned from many vertebrates, and three endogenous ligands (the endocannabinoids arachidonoyl ethanolamide, 2-arachidonoyl glycerol and 2-arachidonoyl-glycerol ether) have been characterized. Cannabinoid receptor type 1 (CB(1)) is expressed predominantly in the central and peripheral nervous system, while cannabinoid receptor type 2 (CB(2)) is present almost exclusively in immune cells. Cannabinoid receptors have not yet been cloned from invertebrates, but binding proteins for endocannabinoids, endocannabinoids and metabolic enzyme activity have been described in a variety of invertebrates except for molting invertebrates such as Caenorhabditis elegans and Drosophila. In the central nervous system of mammals, there is strong evidence emerging that the CB(1) and its ligands comprise a neuromodulatory system functionally interacting with other neurotransmitter systems. Furthermore, the presynaptic localization of CB(1) together with the results obtained from electrophysiological experiments strengthen the notion that in cerebellum and hippocampus and possibly in other regions of the central nervous system, endocannabinoids may act as retrograde messengers to suppress neurotransmitter release at the presynaptic site. Many recent studies using genetically modified mouse lines which lack CB(1) and/or CB(2) finally could show the importance of cannabinoid receptors in animal physiology and will contribute to unravel the full complexity of the cannabinoid system.
Collapse
Affiliation(s)
- Beat Lutz
- Group Molecular Genetics of Behavior, Max-Planck-Institute of Psychiatry, Kraepelinstrasse 2-10, D-80804 Munich, Germany.
| |
Collapse
|