1
|
Inserra A, Giorgini G, Lacroix S, Bertazzo A, Choo J, Markopolous A, Grant E, Abolghasemi A, De Gregorio D, Flamand N, Rogers G, Comai S, Silvestri C, Gobbi G, Di Marzo V. Effects of repeated lysergic acid diethylamide (LSD) on the mouse brain endocannabinoidome and gut microbiome. Br J Pharmacol 2023; 180:721-739. [PMID: 36316276 DOI: 10.1111/bph.15977] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2022] [Revised: 10/06/2022] [Accepted: 10/07/2022] [Indexed: 11/05/2022] Open
Abstract
BACKGROUND AND PURPOSE Psychedelics elicit prosocial, antidepressant and anxiolytic effects via neuroplasticity, neurotransmission and neuro-immunomodulatory mechanisms. Whether psychedelics affect the brain endocannabinoid system and its extended version, the endocannabinoidome (eCBome) or the gut microbiome, remains unknown. EXPERIMENTAL APPROACH Adult C57BL/6N male mice were administered lysergic acid diethylamide (LSD) or saline for 7 days. Sociability was assessed in the direct social interaction and three chambers tests. Prefrontal cortex and hippocampal endocannabinoids, endocannabinoid-like mediators and metabolites were quantified via high-pressure liquid chromatography with tandem mass spectrometry (HPLC-MS/MS). Neurotransmitter levels were assessed via HPLC-UV/fluorescence. Gut microbiome changes were investigated by 16S ribosomal DNA sequencing. KEY RESULTS LSD increased social preference and novelty and decreased hippocampal levels of the N-acylethanolamines N-linoleoylethanolamine (LEA), anandamide (N-arachidonoylethanolamine) and N-docosahexaenoylethanolamine (DHEA); the monoacylglycerol 1/2-docosahexaenoylglycerol (1/2-DHG); the prostaglandins D2 (PGD2 ) and F2α (PGF2α ); thromboxane 2 and kynurenine. Prefrontal eCBome mediator and metabolite levels were less affected by the treatment. LSD decreased Shannon alpha diversity of the gut microbiota, prevented the decrease in the Firmicutes:Bacteroidetes ratio observed in saline-treated mice and altered the relative abundance of the bacterial taxa Bifidobacterium, Ileibacterium, Dubosiella and Rikenellaceae RC9. CONCLUSIONS AND IMPLICATIONS The prosocial effects elicited by repeated LSD administration are accompanied by alterations of hippocampal eCBome and kynurenine levels, and the composition of the gut microbiota. Modulation of the hippocampal eCBome and kynurenine pathway might represent a mechanism by which psychedelic compounds elicit prosocial effects and affect the gut microbiome.
Collapse
Affiliation(s)
- Antonio Inserra
- Neurobiological Psychiatry Unit, Department of Psychiatry, McGill University, Montreal, Canada
| | - Giada Giorgini
- Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie de Québec (CRIUCPQ), Québec, Canada.,Département de Médecine, Faculté de Médecine, Université Laval, Québec, Canada.,Joint International Unit between the National Research Council (CNR) of Italy and Université Laval on Chemical and Biomolecular Research on the Microbiome and its Impact on Metabolic Health and Nutrition (UMI-MicroMeNu), Institute of Biomolecular Chemistry, CNR, Pozzuoli, Italy.,Canada Research Excellence Chair on the Microbiome-Endocannabinoidome Axis in Metabolic Health (CERC-MEND), Université Laval, Québec, Canada
| | - Sebastien Lacroix
- Institut sur la Nutrition et les Aliments Fonctionnels (INAF), Québec, Canada
| | - Antonella Bertazzo
- Department of Pharmaceutical and Pharmacological Sciences, University of Padua, Padua, Italy
| | - Jocelyn Choo
- Microbiome and Host Health, South Australian Health and Medical Research Institute, Adelaide, South Australia, Australia.,Infection and Immunity, Flinders Health and Medical Research Institute, College of Medicine and Public Health, Flinders University, Bedford Park, South Australia, Australia
| | - Athanasios Markopolous
- Neurobiological Psychiatry Unit, Department of Psychiatry, McGill University, Montreal, Canada
| | - Emily Grant
- Neurobiological Psychiatry Unit, Department of Psychiatry, McGill University, Montreal, Canada
| | - Armita Abolghasemi
- Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie de Québec (CRIUCPQ), Québec, Canada.,Département de Médecine, Faculté de Médecine, Université Laval, Québec, Canada
| | - Danilo De Gregorio
- Neurobiological Psychiatry Unit, Department of Psychiatry, McGill University, Montreal, Canada.,Division of Neuroscience, Vita-Salute San Raffaele University, Milan, Italy
| | - Nicolas Flamand
- Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie de Québec (CRIUCPQ), Québec, Canada.,Département de Médecine, Faculté de Médecine, Université Laval, Québec, Canada.,Canada Research Excellence Chair on the Microbiome-Endocannabinoidome Axis in Metabolic Health (CERC-MEND), Université Laval, Québec, Canada
| | - Geraint Rogers
- Microbiome and Host Health, South Australian Health and Medical Research Institute, Adelaide, South Australia, Australia.,Infection and Immunity, Flinders Health and Medical Research Institute, College of Medicine and Public Health, Flinders University, Bedford Park, South Australia, Australia
| | - Stefano Comai
- Neurobiological Psychiatry Unit, Department of Psychiatry, McGill University, Montreal, Canada.,Department of Pharmaceutical and Pharmacological Sciences, University of Padua, Padua, Italy.,Department of Biomedical Sciences, University of Padua, Padua, Italy
| | - Cristoforo Silvestri
- Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie de Québec (CRIUCPQ), Québec, Canada.,Département de Médecine, Faculté de Médecine, Université Laval, Québec, Canada.,Canada Research Excellence Chair on the Microbiome-Endocannabinoidome Axis in Metabolic Health (CERC-MEND), Université Laval, Québec, Canada.,Institut sur la Nutrition et les Aliments Fonctionnels (INAF), Québec, Canada.,Centre NUTRISS, École de Nutrition, Faculté des Sciences de l'Agriculture et de l'Alimentation (FSAA), Université Laval, Québec, Canada
| | - Gabriella Gobbi
- Neurobiological Psychiatry Unit, Department of Psychiatry, McGill University, Montreal, Canada
| | - Vincenzo Di Marzo
- Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie de Québec (CRIUCPQ), Québec, Canada.,Département de Médecine, Faculté de Médecine, Université Laval, Québec, Canada.,Joint International Unit between the National Research Council (CNR) of Italy and Université Laval on Chemical and Biomolecular Research on the Microbiome and its Impact on Metabolic Health and Nutrition (UMI-MicroMeNu), Institute of Biomolecular Chemistry, CNR, Pozzuoli, Italy.,Canada Research Excellence Chair on the Microbiome-Endocannabinoidome Axis in Metabolic Health (CERC-MEND), Université Laval, Québec, Canada.,Institut sur la Nutrition et les Aliments Fonctionnels (INAF), Québec, Canada.,Centre NUTRISS, École de Nutrition, Faculté des Sciences de l'Agriculture et de l'Alimentation (FSAA), Université Laval, Québec, Canada
| |
Collapse
|
2
|
Wang M, Liu H, Ma Z. Roles of the Cannabinoid System in the Basal Ganglia in Parkinson’s Disease. Front Cell Neurosci 2022; 16:832854. [PMID: 35264932 PMCID: PMC8900732 DOI: 10.3389/fncel.2022.832854] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Accepted: 01/31/2022] [Indexed: 12/26/2022] Open
Abstract
Parkinson’s disease (PD) is a neurodegenerative disease usually caused by neuroinflammation, oxidative stress and other etiologies. Recent studies have found that the cannabinoid system present in the basal ganglia has a strong influence on the progression of PD. Altering the cannabinoid receptor activation status by modulating endogenous cannabinoid (eCB) levels can exert an anti-movement disorder effect. Therefore, the development of drugs that modulate the endocannabinoid system may be a novel strategy for the treatment of PD. However, eCB regulation is complex, with diverse cannabinoid receptor functions and the presence of dopaminergic, glutamatergic, and γ-aminobutyric signals interacting with cannabinoid signaling in the basal ganglia region. Therefore, the study of eCB is challenging. Here, we have described the function of the cannabinoid system in the basal ganglia and its association with PD in three parts (eCBs, cannabinoid receptors, and factors regulating the cannabinoid metabolism) and summarized the mechanisms of action related to the cannabinoid analogs currently aimed at treating PD. The shortcomings identified from previous studies and the directions that should be explored in the future will provide insights into new approaches and ideas for the future development of cannabinoid-based drugs and the treatment of PD.
Collapse
Affiliation(s)
- Mengya Wang
- Department of Physiology, School of Basic Medicine, Institute of Brain Science and Disorders, Qingdao University, Qingdao, China
| | - Huayuan Liu
- Department of Hepatobiliary Surgery, The Affiliated Qingdao Municipal Hospital of Qingdao University, Qingdao, China
| | - Zegang Ma
- Department of Physiology, School of Basic Medicine, Institute of Brain Science and Disorders, Qingdao University, Qingdao, China
- *Correspondence: Zegang Ma,
| |
Collapse
|
3
|
Haroutounian S, Arendt-Nielsen L, Belton J, Blyth FM, Degenhardt L, Forti MD, Eccleston C, Finn DP, Finnerup NB, Fisher E, Fogarty AE, Gilron I, Hohmann AG, Kalso E, Krane E, Mohiuddin M, Moore RA, Rowbotham M, Soliman N, Wallace M, Zinboonyahgoon N, Rice ASC. International Association for the Study of Pain Presidential Task Force on Cannabis and Cannabinoid Analgesia: research agenda on the use of cannabinoids, cannabis, and cannabis-based medicines for pain management. Pain 2021; 162:S117-S124. [PMID: 34138827 PMCID: PMC8855877 DOI: 10.1097/j.pain.0000000000002266] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Accepted: 03/10/2021] [Indexed: 01/08/2023]
Abstract
ABSTRACT The President of the International Association for the Study of Pain established a task force on cannabis and cannabinoid analgesia to systematically examine the evidence on (1) analgesic pharmacology of cannabinoids and preclinical evidence on their efficacy in animal models of injury-related or pathological persistent pain; (2) the clinical efficacy of cannabis, cannabinoids, and cannabis-based medicines for pain; (3) harms related to long-term use of cannabinoids; as well as (4) societal issues and policy implications related to the use of these compounds for pain management. Here, we summarize key knowledge gaps identified in the task force outputs and propose a research agenda for generating high-quality evidence on the topic. The systematic assessment of preclinical and clinical literature identified gaps in rigor of study design and reporting across the translational spectrum. We provide recommendations to improve the quality, rigor, transparency, and reproducibility of preclinical and clinical research on cannabis and cannabinoids for pain, as well as for the conduct of systematic reviews on the topic. Gaps related to comprehensive understanding of the endocannabinoid system and cannabinoid pharmacology, including pharmacokinetics and drug formulation aspects, are discussed. We outline key areas where high-quality clinical trials with cannabinoids are needed. Remaining important questions about long-term and short-term safety of cannabis and cannabinoids are emphasized. Finally, regulatory, societal, and policy challenges associated with medicinal and nonmedicinal use of cannabis are highlighted, with recommendations for improving patient safety and reducing societal harms in the context of pain management.
Collapse
Affiliation(s)
- Simon Haroutounian
- Division of Clinical and Translational Research and Washington University Pain Center. Department of Anesthesiology, Washington University School of Medicine. St Louis, MO, USA
| | - Lars Arendt-Nielsen
- Center for Neuroplasticity and Pain (CNAP) and Center for Sensory-Motor Interaction (SMI), Department of Health Science and Technology, School of Medicine, Aalborg University, Aalborg, Denmark
| | - Joletta Belton
- Endless Possibilities Initiative, Fraser, CO, USA; Global Alliance of Pain Patient Advocates (GAPPA) Presidential Task Force
| | - Fiona M. Blyth
- Sydney School of Public Health, Faculty of Medicine and Health, University of Sydney, Camperdown, NSW 2006, Australia
| | - Louisa Degenhardt
- National Drug and Alcohol Research Centre, University of New South Wales, Sydney, NSW 2052, Australia
| | - Marta Di Forti
- Social, Genetic and Developmental Psychiatry Centre, Institute of Psychiatry, Psychology and Neuroscience, King’s College London, London SE5 8AF, UK. National Institute for Health Research (NIHR) Mental Health Biomedical Research Centre at South London and Maudsley NHS Foundation Trust and King’s College London, UK. South London and Maudsley NHS Mental Health Foundation Trust, London, UK
| | - Christopher Eccleston
- Centre for Pain Research. The University of Bath, Bath, UK, & Department of Clinical and Health Psychology, The University of Ghent, Belgium
| | - David P. Finn
- Pharmacology and Therapeutics, School of Medicine, Galway Neuroscience Centre and Centre for Pain Research, Human Biology Building, National University of Ireland Galway, University Road, Galway, Ireland
| | - Nanna B Finnerup
- Danish Pain Research Center, Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - Emma Fisher
- Centre for Pain Research. The University of Bath, Bath, UK
| | - Alexandra E. Fogarty
- Department of Neurology, Division of Physical Medicine & Rehabilitation, Washington University School of Medicine. St Louis, MO, USA
| | - Ian Gilron
- Departments of Anesthesiology & Perioperative Medicine and Biomedical & Molecular Sciences, Kingston Health Sciences Centre and Queen’s University; Centre for Neuroscience Studies, Queen’s University; School of Policy Studies, Queen’s University, Kingston, Canada
| | - Andrea G. Hohmann
- Department of Psychological and Brain Sciences, Program in Neuroscience, Gill Center for Biomolecular Science, Indiana University, Bloomington, IN, USA
| | - Eija Kalso
- Department of Pharmacology and SleepWell Research Programme, University of Helsinki; Department of Anaesthesiology, Intensive Care and Pain Medicine, Helsinki University Hospital
| | - Elliot Krane
- Departments of Anesthesiology, Perioperative, and Pain Medicine, & Pediatrics, Stanford University School of Medicine, Stanford, California, USA
| | - Mohammed Mohiuddin
- Department of Anesthesiology & Perioperative Medicine and, Queen’s University, Kingston, Canada
| | | | - Michael Rowbotham
- Department of Anesthesia, University of California, San Francisco, California, USA
| | - Nadia Soliman
- Pain Research, Department of Surgery & Cancer, Faculty of Medicine, Imperial College London, UK
| | - Mark Wallace
- Division of Pain Medicine, Department of Anesthesiology, University of California San Diego
| | | | - Andrew SC Rice
- Pain Research, Department of Surgery & Cancer, Faculty of Medicine, Imperial College London, UK
| |
Collapse
|
4
|
Abstract
![]()
Developing
drugs for the central nervous system (CNS) requires
fine chemical modifications, as a strict balance between size and
lipophilicity is necessary to improve the permeability through the
blood-brain barrier (BBB).
In this context, morpholine and its analogues represent valuable heterocycles,
due to their conformational and physicochemical properties. In fact,
the presence of a weak basic nitrogen atom and of an oxygen atom at
the opposite position provides a peculiar pKa value and a flexible conformation to the ring, thus allowing
it to take part in several lipophilic–hydrophilic interactions,
and to improve blood solubility and brain permeability of the overall
structure. In CNS-active compounds, morpholines are used (1) to enhance
the potency through molecular interactions, (2) to act as a scaffold
directing the appendages in the correct position, and (3) to modulate
pharmacokinetic/pharmacodynamic (PK/PD) properties. In this perspective,
selected morpholine-containing CNS drug candidates are discussed to
reveal the active pharmacophores accountable for the (1) modulation
of receptors involved in mood disorders and pain, (2) bioactivity
toward enzymes and receptors responsible for neurodegenerative diseases,
and (3) inhibition of enzymes involved in the pathology of CNS tumors.
The medicinal chemistry/pharmacological activity of morpholine derivatives
is discussed, in the effort to highlight the importance of morpholine
ring interactions in the active site of different targets, particularly
reporting binding features retrieved from PDB data, when available.
Collapse
Affiliation(s)
- Elena Lenci
- Department of Chemistry “Ugo Schiff”, University of Florence, via della Lastruccia 13, 50019 Sesto Fiorentino, Florence, Italy
| | - Lorenzo Calugi
- Department of Chemistry “Ugo Schiff”, University of Florence, via della Lastruccia 13, 50019 Sesto Fiorentino, Florence, Italy
| | - Andrea Trabocchi
- Department of Chemistry “Ugo Schiff”, University of Florence, via della Lastruccia 13, 50019 Sesto Fiorentino, Florence, Italy
| |
Collapse
|
5
|
Canseco-Alba A, Rodríguez-Manzo G. Endocannabinoids Interact With the Dopaminergic System to Increase Sexual Motivation: Lessons From the Sexual Satiety Phenomenon. Front Behav Neurosci 2019; 13:184. [PMID: 31474840 PMCID: PMC6702338 DOI: 10.3389/fnbeh.2019.00184] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2019] [Accepted: 07/29/2019] [Indexed: 12/15/2022] Open
Abstract
In male rats, copulation to satiety induces a long-lasting sexual inhibitory state, considered to rely on a decreased sexual motivation. Dopaminergic transmission at the mesolimbic system plays a central role in the regulation of male sexual motivation. Endocannabinoids (eCBs) modulate the activity of the mesolimbic system and both dopamine (DA) and cannabinoid receptor activation reverses the sexual inhibition that characterizes sexually satiated rats. The eCB anandamide reverses sexual satiety when systemically administered or infused into the ventral tegmental area (VTA), the region where the activity of mesolimbic dopaminergic neurons is regulated. Thus, it could be thought that sexual motivation is diminished during the long-lasting sexual inhibition of sexually satiated rats and that eCBs reverse that inhibition through the modulation of the dopaminergic system. To test this hypothesis, we assessed the motivational state of sexually satiated male rats and determined if 2-arachidonoylglycerol (2-AG), the most abundant eCB and a full cannabinoid receptor agonist, also reversed the sexual inhibitory state. To establish the possible interaction between 2-AG and anandamide with the dopaminergic system for the reversal of sexual satiety, we analyzed the effects of the co-administration of each eCB and DA receptor agonists or antagonists. Results showed that 24-h after copulation to satiety, when the sexual inhibition is well established, the males’ sexual motivation is diminished as measured in the sexual incentive motivation test. 2-AG, similarly to anandamide, reverses sexual satiety through the activation of CB1 receptors and both eCBs interact with the dopaminergic system to reverse the sexual inhibitory state. 2-AG effects are mediated by the modulation of the D2-like DA receptor family, whereas anandamide’s effects are clearly mediated by the modulation of the D1-like DA receptor family and the activation of D2-like DA receptors. Present results evidence that a reduced sexual motivation underlies the sexual inhibitory state of sexually satiated rats and support the notion that eCBs reverse sexual satiety by modulating dopaminergic transmission, presumably at the mesolimbic system. Anandamide and 2-AG have a different interaction with D1-like and D2-like DA receptor families. Altogether present data endorse the association of the eCB system with the regulation of the motivational tone at the mesolimbic system.
Collapse
Affiliation(s)
- Ana Canseco-Alba
- Departamento de Farmacobiología, Centro de Investigación y de Estudios Avanzados (Cinvestav-Sede Sur), Ciudad de México, México
| | - Gabriela Rodríguez-Manzo
- Departamento de Farmacobiología, Centro de Investigación y de Estudios Avanzados (Cinvestav-Sede Sur), Ciudad de México, México
| |
Collapse
|
6
|
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
|
7
|
Schindler CW, Scherma M, Redhi GH, Vadivel SK, Makriyannis A, Goldberg SR, Justinova Z. Self-administration of the anandamide transport inhibitor AM404 by squirrel monkeys. Psychopharmacology (Berl) 2016; 233:1867-77. [PMID: 26803499 PMCID: PMC4846479 DOI: 10.1007/s00213-016-4211-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/11/2015] [Accepted: 01/06/2016] [Indexed: 11/30/2022]
Abstract
RATIONALE N-(4-hydroxyphenyl)-arachidonamide (AM404) is an anandamide transport inhibitor shown to reduce rewarding and relapse-inducing effects of nicotine in several animal models of tobacco dependence. However, the reinforcing/rewarding effects of AM404 are not clear. OBJECTIVES We investigated whether AM404 maintains self-administration behavior or reinstates extinguished drug seeking in squirrel monkeys. METHODS AND RESULTS In monkeys with a history of anandamide or cocaine self-administration, we substituted injections of AM404 (1-100 μg/kg/injection). Using a 10-response, fixed-ratio schedule, self-administration behavior was maintained by AM404. Dose-response curves had inverted U shapes, with peak response rates occurring at a dose of 10 μg/kg/injection. In anandamide-experienced monkeys, we also demonstrated self-administration of another anandamide transport inhibitor VDM11. In addition to supporting self-administration, priming injections of AM404 (0.03-0.3 mg/kg) reinstated drug-seeking behavior previously reinforced by cannabinoids (∆(9)-tetrahydrocannabinol (THC) or anandamide) or cocaine. Both AM404 self-administration behavior and reinstatement of drug seeking by AM404 were reduced by treatment with the cannabinoid CB1 receptor antagonist/inverse agonist rimonabant (0.3 mg/kg). Moreover, the reinforcing effects of AM404 were potentiated by the treatment with the fatty acid amide hydrolase (FAAH) inhibitor URB597 (0.3 mg/kg) suggesting a major role of anandamide in these effects. Finally, AM404 (0.3 mg/kg) potentiated the reinforcing effects of anandamide but not those of cocaine. CONCLUSIONS In non-human primates, AM404 effectively reinforced self-administration behavior and induced reinstatement of drug-seeking behavior in abstinent monkeys. These effects appeared to be mediated by cannabinoid CB1 receptors. Therefore, compounds that promote actions of endocannabinoids throughout the brain by inhibiting their membrane transport may have a potential for abuse.
Collapse
Affiliation(s)
- Charles W. Schindler
- Preclinical Pharmacology Section, Behavioral Neuroscience Research Branch, Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health, Department of Health and Human Services, Baltimore, Maryland, USA,Corresponding author: Preclinical Pharmacology Section, National Institute on Drug Abuse, NIH, Biomedical Research Center, 251 Bayview Boulevard, Baltimore, MD 21224;
| | - Maria Scherma
- Department of Biomedical Sciences, Section of Neuroscience and Clinical Pharmacology, University of Cagliari, Monserrato, Italy
| | - Godfrey H. Redhi
- Preclinical Pharmacology Section, Behavioral Neuroscience Research Branch, Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health, Department of Health and Human Services, Baltimore, Maryland, USA
| | - Subramanian K. Vadivel
- Center for Drug Discovery, Department of Pharmaceutical Sciences, Northeastern University, Boston, Massachusetts, USA
| | - Alexandros Makriyannis
- Center for Drug Discovery, Departments of Pharmaceutical Sciences and Chemistry and Chemical Biology, Northeastern University, Boston, Massachusetts, USA
| | - Steven R. Goldberg
- Preclinical Pharmacology Section, Behavioral Neuroscience Research Branch, Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health, Department of Health and Human Services, Baltimore, Maryland, USA
| | - Zuzana Justinova
- Preclinical Pharmacology Section, Behavioral Neuroscience Research Branch, Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health, Department of Health and Human Services, Baltimore, Maryland, USA
| |
Collapse
|
8
|
Tyukhtenko S, Karageorgos I, Rajarshi G, Zvonok N, Pavlopoulos S, Janero DR, Makriyannis A. Specific Inter-residue Interactions as Determinants of Human Monoacylglycerol Lipase Catalytic Competency: A ROLE FOR GLOBAL CONFORMATIONAL CHANGES. J Biol Chem 2015; 291:2556-65. [PMID: 26555264 DOI: 10.1074/jbc.m115.670257] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2015] [Indexed: 11/06/2022] Open
Abstract
The serine hydrolase monoacylglycerol lipase (MGL) functions as the main metabolizing enzyme of 2-arachidonoyl glycerol, an endocannabinoid signaling lipid whose elevation through genetic or pharmacological MGL ablation exerts therapeutic effects in various preclinical disease models. To inform structure-based MGL inhibitor design, we report the direct NMR detection of a reversible equilibrium between active and inactive states of human MGL (hMGL) that is slow on the NMR time scale and can be modulated in a controlled manner by pH, temperature, and select point mutations. Kinetic measurements revealed that hMGL substrate turnover is rate-limited across this equilibrium. We identify a network of aromatic interactions and hydrogen bonds that regulates hMGL active-inactive state interconversion. The data highlight specific inter-residue interactions within hMGL modulating the enzymes function and implicate transitions between active (open) and inactive (closed) states of the hMGL lid domain in controlling substrate access to the enzymes active site.
Collapse
Affiliation(s)
- Sergiy Tyukhtenko
- From the Center for Drug Discovery and Departments of Pharmaceutical Sciences and Chemistry and Chemical Biology, Northeastern University, Boston, Massachusetts 02115-5000 and
| | - Ioannis Karageorgos
- From the Center for Drug Discovery and Departments of Pharmaceutical Sciences and Chemistry and Chemical Biology, Northeastern University, Boston, Massachusetts 02115-5000 and
| | - Girija Rajarshi
- From the Center for Drug Discovery and Departments of Pharmaceutical Sciences and Chemistry and Chemical Biology, Northeastern University, Boston, Massachusetts 02115-5000 and
| | - Nikolai Zvonok
- From the Center for Drug Discovery and Departments of Pharmaceutical Sciences and Chemistry and Chemical Biology, Northeastern University, Boston, Massachusetts 02115-5000 and
| | - Spiro Pavlopoulos
- From the Center for Drug Discovery and Departments of Pharmaceutical Sciences and Chemistry and Chemical Biology, Northeastern University, Boston, Massachusetts 02115-5000 and
| | - David R Janero
- From the Center for Drug Discovery and Departments of Pharmaceutical Sciences and Chemistry and Chemical Biology, Northeastern University, Boston, Massachusetts 02115-5000 and
| | - Alexandros Makriyannis
- From the Center for Drug Discovery and Departments of Pharmaceutical Sciences and Chemistry and Chemical Biology, Northeastern University, Boston, Massachusetts 02115-5000 and King Abdulaziz University, Jeddah, 22254, Saudi Arabia
| |
Collapse
|
9
|
Promising cannabinoid-based therapies for Parkinson's disease: motor symptoms to neuroprotection. Mol Neurodegener 2015; 10:17. [PMID: 25888232 PMCID: PMC4404240 DOI: 10.1186/s13024-015-0012-0] [Citation(s) in RCA: 86] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2015] [Accepted: 03/23/2015] [Indexed: 11/27/2022] Open
Abstract
Parkinson’s disease (PD) is a slow insidious neurological disorder characterized by a loss of dopaminergic neurons in the midbrain. Although several recent preclinical advances have proposed to treat PD, there is hardly any clinically proved new therapeutic for its cure. Increasing evidence suggests a prominent modulatory function of the cannabinoid signaling system in the basal ganglia. Hence, use of cannabinoids as a new therapeutic target has been recommended as a promising therapy for PD. The elements of the endocannabinoid system are highly expressed in the neural circuit of basal ganglia wherein they bidirectionally interact with dopaminergic, glutamatergic, and GABAergic signaling systems. As the cannabinoid signaling system undergoes a biphasic pattern of change during progression of PD, it explains the motor inhibition typically observed in patients with PD. Cannabinoid agonists such as WIN-55,212-2 have been demonstrated experimentally as neuroprotective agents in PD, with respect to their ability to suppress excitotoxicity, glial activation, and oxidative injury that causes degeneration of dopaminergic neurons. Additional benefits provided by cannabinoid related compounds including CE-178253, oleoylethanolamide, nabilone and HU-210 have been reported to possess efficacy against bradykinesia and levodopa-induced dyskinesia in PD. Despite promising preclinical studies for PD, use of cannabinoids has not been studied extensively at the clinical level. In this review, we reassess the existing evidence suggesting involvement of the endocannabinoid system in the cause, symptomatology, and treatment of PD. We will try to identify future threads of research that will help in the understanding of the potential therapeutic benefits of the cannabinoid system for treating PD.
Collapse
|
10
|
Nasr ML, Shi X, Bowman AL, Johnson M, Zvonok N, Janero DR, Vemuri VK, Wales TE, Engen JR, Makriyannis A. Membrane phospholipid bilayer as a determinant of monoacylglycerol lipase kinetic profile and conformational repertoire. Protein Sci 2013; 22:774-87. [PMID: 23553709 DOI: 10.1002/pro.2257] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2013] [Revised: 03/07/2013] [Accepted: 03/19/2013] [Indexed: 11/10/2022]
Abstract
The membrane-associated serine hydrolase, monoacylglycerol lipase (MGL), is a well-recognized therapeutic target that regulates endocannabinoid signaling. Crystallographic studies, while providing structural information about static MGL states, offer no direct experimental insight into the impact of MGL's membrane association upon its structure-function landscape. We report application of phospholipid bilayer nanodiscs as biomembrane models with which to evaluate the effect of a membrane system on the catalytic properties and conformational dynamics of human MGL (hMGL). Anionic and charge-neutral phospholipid bilayer nanodiscs enhanced hMGL's kinetic properties [apparent maximum velocity (Vmax) and substrate affinity (Km)]. Hydrogen exchange mass spectrometry (HX MS) was used as a conformational analysis method to profile experimentally the extent of hMGL-nanodisc interaction and its impact upon hMGL structure. We provide evidence that significant regions of hMGL lid-domain helix α4 and neighboring helix α6 interact with the nanodisc phospholipid bilayer, anchoring hMGL in a more open conformation to facilitate ligand access to the enzyme's substrate-binding channel. Covalent modification of membrane-associated hMGL by the irreversible carbamate inhibitor, AM6580, shielded the active site region, but did not increase solvent exposure of the lid domain, suggesting that the inactive, carbamylated enzyme remains intact and membrane associated. Molecular dynamics simulations generated conformational models congruent with the open, membrane-associated topology of active and inhibited, covalently-modified hMGL. Our data indicate that hMGL interaction with a phospholipid membrane bilayer induces regional changes in the enzyme's conformation that favor its recruiting lipophilic substrate/inhibitor from membrane stores to the active site via the lid, resulting in enhanced hMGL catalytic activity and substrate affinity.
Collapse
Affiliation(s)
- Mahmoud L Nasr
- Center for Drug Discovery and Department of Chemistry, Northeastern University, Boston, Massachusetts 02115-5000, USA
| | | | | | | | | | | | | | | | | | | |
Collapse
|
11
|
Zogopoulos P, Vasileiou I, Patsouris E, Theocharis S. The neuroprotective role of endocannabinoids against chemical-induced injury and other adverse effects. J Appl Toxicol 2013; 33:246-64. [DOI: 10.1002/jat.2828] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2012] [Revised: 08/31/2012] [Accepted: 09/01/2012] [Indexed: 12/21/2022]
Affiliation(s)
- Panagiotis Zogopoulos
- 1st Department of Pathology, Medical School; National and Kapodistrian University of Athens; Athens; Greece
| | - Ioanna Vasileiou
- 1st Department of Pathology, Medical School; National and Kapodistrian University of Athens; Athens; Greece
| | - Efstratios Patsouris
- 1st Department of Pathology, Medical School; National and Kapodistrian University of Athens; Athens; Greece
| | - Stamatios Theocharis
- 1st Department of Pathology, Medical School; National and Kapodistrian University of Athens; Athens; Greece
| |
Collapse
|
12
|
Zogopoulos P, Vasileiou I, Patsouris E, Theocharis SE. The role of endocannabinoids in pain modulation. Fundam Clin Pharmacol 2013; 27:64-80. [PMID: 23278562 DOI: 10.1111/fcp.12008] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2011] [Revised: 09/03/2012] [Accepted: 09/21/2012] [Indexed: 12/16/2022]
Abstract
The endocannabinoid system (ES) is comprised of cannabinoid (CB) receptors, their endogenous ligands (endocannabinoids), and proteins responsible for their metabolism. Endocannabinoids serve as retrograde signaling messengers in GABAergic and glutamatergic synapses, as well as modulators of postsynaptic transmission, that interact with other neurotransmitters. Physiological stimuli and pathological conditions lead to differential increases in brain endocannabinoids that regulate distinct biological functions. Furthermore, endocannabinoids modulate neuronal, glial, and endothelial cell function and exert neuromodulatory, anti-excitotoxic, anti-inflammatory, and vasodilatory effects. Analgesia is one of the principal therapeutic targets of cannabinoids. Cannabinoid analgesia is based on the suppression of spinal and thalamic nociceptive neurons, but peripheral sites of action have also been identified. The chronic pain that occasionally follows peripheral nerve injury differs fundamentally from inflammatory pain and is an area of considerable unmet therapeutic need. Over the last years, considerable progress has been made in understanding the role of the ES in the modulation of pain. Endocannabinoids have been shown to behave as analgesics in models of both acute nociception and clinical pain such as inflammation and painful neuropathy. The framework for such analgesic effects exists in the CB receptors, which are found in areas of the nervous system important for pain processing and in immune cells that regulate the neuro-immune interactions that mediate the inflammatory hyperalgesia. The purpose of this review is to present the available research and clinical data, up to date, regarding the ES and its role in pain modulation, as well as its possible therapeutic perspectives.
Collapse
Affiliation(s)
- Panagiotis Zogopoulos
- First Department of Pathology, Medical School, University of Athens, Goudi, Athens, Greece
| | | | | | | |
Collapse
|
13
|
Naidoo V, Karanian DA, Vadivel SK, Locklear JR, Wood JT, Nasr M, Quizon PMP, Graves EE, Shukla V, Makriyannis A, Bahr BA. Equipotent inhibition of fatty acid amide hydrolase and monoacylglycerol lipase - dual targets of the endocannabinoid system to protect against seizure pathology. Neurotherapeutics 2012; 9:801-13. [PMID: 22270809 PMCID: PMC3480564 DOI: 10.1007/s13311-011-0100-y] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Advances in the understanding of the endogenous cannabinoid system have led to several therapeutic indications for new classes of compounds that enhance cannabinergic responses. Endocannabinoid levels are elevated during pathogenic conditions, and inhibitors of endocannabinoid inactivation promote such on-demand responses. The endocannabinoids anandamide and 2-arachidonoyl glycerol have been implicated in protective signaling against excitotoxic episodes, including seizures. To better understand modulatory pathways that can exploit such responses, we used the new generation compound AM6701 that blocks both the anandamide-deactivating enzyme fatty acid amide hydrolase (FAAH) and the 2-arachidonoyl glycerol-deactivating enzyme monoacylglycerol lipase (MAGL) with equal potency. Also studied was the structural isomer AM6702 which is 44-fold more potent for inhibiting FAAH versus MAGL. When applied before and during kainic acid (KA) exposure to cultured hippocampal slices, AM6701 protected against the resulting excitotoxic events of calpain-mediated cytoskeletal damage, loss of presynaptic and postsynaptic proteins, and pyknotic changes in neurons. The equipotent inhibitor was more effective than its close relative AM6702 at protecting against the neurodegenerative cascade assessed in the slice model. In vivo, AM6701 was also the more effective compound for reducing the severity of KA-induced seizures and protecting against behavioral deficits linked to seizure damage. Corresponding with the behavioral improvements, cytoskeletal and synaptic protection was elicited by AM6701, as found in the KA-treated hippocampal slice model. It is proposed that the influence of AM6701 on FAAH and MAGL exerts a synergistic action on the endocannabinoid system, thereby promoting the protective nature of cannabinergic signaling to offset excitotoxic brain injury.
Collapse
Affiliation(s)
- Vinogran Naidoo
- Biotechnology Research and Training Center, William C. Friday Laboratory, University of North Carolina Pembroke, Pembroke, North Carolina 28372 USA
- Department of Biology, University of North Carolina Pembroke, Pembroke, North Carolina USA
| | - David A. Karanian
- Department of Pharmaceutical Sciences and the Neurosciences Program, University of Connecticut, Storrs, Connecticut USA
- Center for Drug Discovery, Northeastern University, Boston, Massachusetts USA
| | | | - Johnathan R. Locklear
- Biotechnology Research and Training Center, William C. Friday Laboratory, University of North Carolina Pembroke, Pembroke, North Carolina 28372 USA
| | - JodiAnne T. Wood
- Center for Drug Discovery, Northeastern University, Boston, Massachusetts USA
| | - Mahmoud Nasr
- Center for Drug Discovery, Northeastern University, Boston, Massachusetts USA
| | - Pamela Marie P. Quizon
- Biotechnology Research and Training Center, William C. Friday Laboratory, University of North Carolina Pembroke, Pembroke, North Carolina 28372 USA
| | - Emily E. Graves
- Biotechnology Research and Training Center, William C. Friday Laboratory, University of North Carolina Pembroke, Pembroke, North Carolina 28372 USA
| | - Vidyanand Shukla
- Center for Drug Discovery, Northeastern University, Boston, Massachusetts USA
| | | | - Ben A. Bahr
- Biotechnology Research and Training Center, William C. Friday Laboratory, University of North Carolina Pembroke, Pembroke, North Carolina 28372 USA
- Department of Biology, University of North Carolina Pembroke, Pembroke, North Carolina USA
- Department of Pharmaceutical Sciences and the Neurosciences Program, University of Connecticut, Storrs, Connecticut USA
| |
Collapse
|
14
|
Campolongo P, Ratano P, Manduca A, Scattoni ML, Palmery M, Trezza V, Cuomo V. The endocannabinoid transport inhibitor AM404 differentially modulates recognition memory in rats depending on environmental aversiveness. Front Behav Neurosci 2012; 6:11. [PMID: 22454620 PMCID: PMC3308193 DOI: 10.3389/fnbeh.2012.00011] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2012] [Accepted: 03/01/2012] [Indexed: 12/12/2022] Open
Abstract
Cannabinoid compounds may influence both emotional and cognitive processes depending on the level of environmental aversiveness at the time of drug administration. However, the mechanisms responsible for these responses remain to be elucidated. The present experiments investigated the effects induced by the endocannabinoid transport inhibitor AM404 (0.5-5 mg/kg, i.p.) on both emotional and cognitive performances of rats tested in a Spatial Open Field task and subjected to different experimental settings, named High Arousal (HA) and Low Arousal (LA) conditions. The two different experimental conditions influenced emotional reactivity independently of drug administration. Indeed, vehicle-treated rats exposed to the LA condition spent more time in the center of the arena than vehicle-treated rats exposed to the HA context. Conversely, the different arousal conditions did not affect the cognitive performances of vehicle-treated animals such as the capability to discriminate a spatial displacement of the objects or an object substitution. AM404 administration did not alter locomotor activity or emotional behavior of animals exposed to both environmental conditions. Interestingly, AM404 administration influenced the cognitive parameters depending on the level of emotional arousal: it impaired the capability of rats exposed to the HA condition to recognize a novel object while it did not induce any impairing effect in rats exposed to the LA condition. These findings suggest that drugs enhancing endocannabinoid signaling induce different effects on recognition memory performance depending on the level of emotional arousal induced by the environmental conditions.
Collapse
Affiliation(s)
- Patrizia Campolongo
- Department of Physiology and Pharmacology, Sapienza University of Rome Rome, Italy
| | | | | | | | | | | | | |
Collapse
|
15
|
Szymanski DW, Papanastasiou M, Melchior K, Zvonok N, Mercier RW, Janero DR, Thakur GA, Cha S, Wu B, Karger B, Makriyannis A. Mass spectrometry-based proteomics of human cannabinoid receptor 2: covalent cysteine 6.47(257)-ligand interaction affording megagonist receptor activation. J Proteome Res 2011; 10:4789-98. [PMID: 21861534 DOI: 10.1021/pr2005583] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The lack of experimental characterization of the structures and ligand-binding motifs of therapeutic G-protein coupled receptors (GPCRs) hampers rational drug discovery. The human cannabinoid receptor 2 (hCB2R) is a class-A GPCR and promising therapeutic target for small-molecule cannabinergic agonists as medicines. Prior mutational and modeling data constitute provisional evidence that AM-841, a high-affinity classical cannabinoid, interacts with cysteine C6.47(257) in hCB2R transmembrane helix 6 (TMH6) to afford improved hCB2R selectivity and unprecedented agonist potency. We now apply bottom-up mass spectrometry (MS)-based proteomics to define directly the hCB2R-AM-841 interaction at the amino-acid level. Recombinant hCB2R, overexpressed as an N-terminal FLAG-tagged/C-terminal 6His-tagged protein (FLAG-hCB2R-6His) with a baculovirus system, was solubilized and purified by immunochromatography as functional receptor. A multiplex multiple reaction monitoring (MRM)-MS method was developed that allowed us to observe unambiguously all seven discrete TMH peptides in the tryptic digest of purified FLAG-hCB2R-6His and demonstrate that AM-841 modifies hCB2R TMH6 exclusively. High-resolution mass spectra of the TMH6 tryptic peptide obtained by Q-TOF MS/MS analysis demonstrated that AM-841 covalently and selectively modifies hCB2R at TMH6 cysteine C6.47(257). These data demonstrate how integration of MS-based proteomics into a ligand-assisted protein structure (LAPS) experimental paradigm can offer guidance to structure-enabled GPCR agonist design.
Collapse
Affiliation(s)
- Dennis W Szymanski
- Center for Drug Discovery, Department of Chemistry and Chemical Biology, College of Science, Northeastern University , Boston, Massachusetts 02115-5000, United States
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
16
|
Järbe TUC, LeMay BJ, Vemuri VK, Vadivel SK, Zvonok A, Makriyannis A. Central mediation and differential blockade by cannabinergics of the discriminative stimulus effects of the cannabinoid CB1 receptor antagonist rimonabant in rats. Psychopharmacology (Berl) 2011; 216:355-65. [PMID: 21369753 PMCID: PMC3727221 DOI: 10.1007/s00213-011-2226-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/22/2010] [Accepted: 02/06/2011] [Indexed: 10/18/2022]
Abstract
RATIONALE Discovery of an endocannabinoid signaling system launched the development of the blocker rimonabant, a cannabinoid CB1 receptor (CB(1)R) antagonist/inverse agonist. Due to untoward effects, this medication was withdrawn and efforts have been directed towards discovering chemicals with more benign profiles. OBJECTIVE This study aims to comparatively evaluate new ligands using a rimonabant discriminated drinking aversion procedure. METHODS Rats discriminated between rimonabant (5.6 mg/kg) and vehicle. The 30 min saccharin (0.1%) drinking after rimonabant pretreatment was followed by injection of lithium chloride (120 mg/kg) in the experimental animals. After vehicle pretreatment, experimental animals were given i.p. NaCl (10 ml/kg). Postdrinking treatment for controls was NaCl, irrespective of pretreatment condition (rimonabant or vehicle). RESULTS The centrally acting neutral CB(1)R antagonist AM4113, but not the limited brain penetrating CB(1)R neutral antagonist AM6545, substituted for rimonabant. The CB(1)R agonists THC (1-10 mg/kg), AM1346 (1-10 mg/kg) did not substitute. The rimonabant-induced conditioned suppression of saccharin drinking was attenuated when CB(1)R agonists AM5983 (0.01-1 mg/kg) and THC (10 mg/kg), but not the CB(1)R agonist AM1346 (0.1-18 mg/kg), were combined with rimonabant (5.6 mg/kg). By varying the injection-to-test interval, we gauged the relative duration of the cueing effects of rimonabant, and the in vivo functional half-life was estimated to be approximately 1.5 h. CONCLUSION A neutral CB(1)R antagonist (AM4113) produced cueing effects similar to those of rimonabant and generalization likely was centrally mediated. The functional cueing effects of rimonabant are relatively short-acting, pharmacologically selective, and differentially blocked by cannabinergics.
Collapse
|
17
|
Howes MJR, Perry E. The Role of Phytochemicals in the Treatment and Prevention of Dementia. Drugs Aging 2011; 28:439-68. [DOI: 10.2165/11591310-000000000-00000] [Citation(s) in RCA: 118] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
|
18
|
Godlewski G, Alapafuja SO, Bátkai S, Nikas SP, Cinar R, Offertáler L, Osei-Hyiaman D, Liu J, Mukhopadhyay B, Harvey-White J, Tam J, Pacak K, Blankman JL, Cravatt BF, Makriyannis A, Kunos G. Inhibitor of fatty acid amide hydrolase normalizes cardiovascular function in hypertension without adverse metabolic effects. ACTA ACUST UNITED AC 2011; 17:1256-66. [PMID: 21095576 DOI: 10.1016/j.chembiol.2010.08.013] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2010] [Revised: 08/03/2010] [Accepted: 08/30/2010] [Indexed: 02/07/2023]
Abstract
The enzyme fatty acid amide hydrolase (FAAH) catalyzes the in vivo degradation of the endocannabinoid anandamide, thus controlling its action at receptors. A novel FAAH inhibitor, AM3506, normalizes the elevated blood pressure and cardiac contractility of spontaneously hypertensive rats (SHR) without affecting these parameters in normotensive rats. These effects are due to blockade of FAAH and a corresponding rise in brain anandamide levels, resulting in CB₁ receptor-mediated decrease in sympathetic tone. The supersensitivity of SHR to CB₁ receptor-mediated cardiovascular depression is related to increased G protein coupling of CB₁ receptors. Importantly, AM3506 does not elicit hyperglycemia and insulin resistance seen with other FAAH inhibitors or in FAAH⁻/⁻ mice, which is related to its inability to inhibit FAAH in the liver due to rapid hepatic uptake and metabolism. This unique activity profile offers improved therapeutic value in hypertension.
Collapse
Affiliation(s)
- Grzegorz Godlewski
- Laboratory of Physiologic Studies, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, 5625 Fishers Lane, Rockville, MD 20852, USA
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
19
|
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
|
20
|
Tiburu EK, Tyukhtenko S, Zhou H, Janero DR, Struppe J, Makriyannis A. Human cannabinoid 1 GPCR C-terminal domain interacts with bilayer phospholipids to modulate the structure of its membrane environment. AAPS JOURNAL 2011; 13:92-8. [PMID: 21234731 DOI: 10.1208/s12248-010-9244-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2010] [Accepted: 11/21/2010] [Indexed: 02/08/2023]
Abstract
G protein-coupled receptors (GPCRs) play critical physiological and therapeutic roles. The human cannabinoid 1 GPCR (hCB1) is a prime pharmacotherapeutic target for addiction and cardiometabolic disease. Our prior biophysical studies on the structural biology of a synthetic peptide representing the functionally significant hCB1 transmembrane helix 7 (TMH7) and its cytoplasmic extension, helix 8 (H8), [hCB1(TMH7/H8)] demonstrated that the helices are oriented virtually perpendicular to each other in membrane-mimetic environments. We identified several hCB1(TMH7/H8) structure-function determinants, including multiple electrostatic amino-acid interactions and a proline kink involving the highly conserved NPXXY motif. In phospholipid bicelles, TMH7 structure, orientation, and topology relative to H8 are dynamically modulated by the surrounding membrane phospholipid bilayer. These data provide a contextual basis for the present solid-state NMR study to investigate whether intermolecular interactions between hCB1(TMH7/H8) and its phospholipid environment may affect membrane-bilayer structure. For this purpose, we measured (1)H-(13)C heteronuclear dipolar couplings for the choline, glycerol, and acyl-chain regions of dimyristoylphosphocholine in a magnetically aligned hCB1(TMH7/H8) bicelle sample. The results identify discrete regional interactions between hCB1(TMH7/H8) and membrane lipid molecules that increase phospholipid motion and decrease phospholipid order, indicating that the peptide's partial traversal of the bilayer alters membrane structure. These data offer new insight into hCB1(TMH7/H8) properties and support the concept that the membrane bilayer itself may serve as a mechanochemical mediator of hCB1/GPCR signal transduction. Since interaction with its membrane environment has been implicated in hCB1 function and its modulation by small-molecule therapeutics, our work should help inform hCB1 pharmacology and the design of hCB1-targeted drugs.
Collapse
Affiliation(s)
- Elvis K Tiburu
- Center for Drug Discovery and Department of Chemistry and Chemical Biology, Northeastern University, 360 Huntington Avenue, 116 Mugar Hall, Boston, Massachusetts 02115-5000, United States of America
| | | | | | | | | | | |
Collapse
|
21
|
Naidoo V, Nikas SP, Karanian DA, Hwang J, Zhao J, Wood JT, Alapafuja SO, Vadivel SK, Butler D, Makriyannis A, Bahr BA. A new generation fatty acid amide hydrolase inhibitor protects against kainate-induced excitotoxicity. J Mol Neurosci 2010; 43:493-502. [PMID: 21069475 DOI: 10.1007/s12031-010-9472-4] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2010] [Accepted: 10/28/2010] [Indexed: 02/02/2023]
Abstract
Endocannabinoids, including anandamide (AEA), have been implicated in neuroprotective on-demand responses. Related to such a response to injury, an excitotoxic kainic acid (KA) injection (i.p.) was found to increase AEA levels in the brain. To modulate the endocannabinoid response during events of excitotoxicity in vitro and in vivo, we utilized a new generation compound (AM5206) that selectively inhibits the AEA deactivating enzyme fatty acid amide hydrolase (FAAH). KA caused calpain-mediated spectrin breakdown, declines in synaptic markers, and disruption of neuronal integrity in cultured hippocampal slices. FAAH inhibition with AM5206 protected against the neurodegenerative cascade assessed in the slice model 24 h postinsult. In vivo, KA administration induced seizures and the same neurodegenerative events exhibited in vitro. When AM5206 was injected immediately after KA in rats, the seizure scores were markedly reduced as were levels of cytoskeletal damage and synaptic protein decline. The pre- and postsynaptic proteins were protected by the FAAH inhibitor to levels comparable to those found in healthy control brains. These data support the idea that endocannabinoids are released and converge on pro-survival pathways that prevent excitotoxic progression.
Collapse
Affiliation(s)
- Vinogran Naidoo
- Biotechnology Research and Training Center, University of North Carolina Pembroke, 115 Livermore Drive, Pembroke, NC 28372-1510, USA
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
22
|
Karageorgos I, Tyukhtenko S, Zvonok N, Janero DR, Sallum C, Makriyannis A. Identification by nuclear magnetic resonance spectroscopy of an active-site hydrogen-bond network in human monoacylglycerol lipase (hMGL): implications for hMGL dynamics, pharmacological inhibition, and catalytic mechanism. MOLECULAR BIOSYSTEMS 2010; 6:1381-8. [PMID: 20464001 PMCID: PMC3697746 DOI: 10.1039/c004515b] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Intramolecular hydrogen bonding is an important determinant of enzyme structure, catalysis, and inhibitor action. Monoacylglycerol lipase (MGL) modulates cannabinergic signaling as the main enzyme responsible for deactivating 2-arachidonoylglycerol (2-AG), a primary endocannabinoid lipid messenger. By enhancing tissue-protective 2-AG tone, targeted MGL inhibitors hold therapeutic promise for managing pain and treating inflammatory and neurodegenerative diseases. We report study of purified, solubilized human MGL (hMGL) to explore the details of hMGL catalysis by using two known covalent hMGL inhibitors, the carbamoyl tetrazole AM6701 and N-arachidonoylmaleimide (NAM), that act through distinct mechanisms. Using proton nuclear magnetic resonance spectroscopy (NMR) with purified wild-type and mutant hMGLs, we have directly observed a strong hydrogen-bond network involving Asp239 and His269 of the catalytic triad and neighboring Leu241 and Cys242 residues. hMGL inhibition by AM6701 alters this hydrogen-bonding pattern through subtle active-site structural rearrangements without influencing hydrogen-bond occupancies. Rapid carbamoylation of hMGL Ser122 by AM6701 and elimination of the leaving group is followed by a slow hydrolysis of the carbamate group, ultimately regenerating catalytically competent hMGL. In contrast, hMGL titration with NAM, which leads to cysteine alkylation, stoichiometrically decreases the population of the active-site hydrogen bonds. NAM prevents reformation of this network, and in this manner inhibits hMGL irreversibly. These data provide detailed molecular insight into the distinctive mechanisms of two covalent hMGL inhibitors and implicate a hydrogen-bond network as a structural feature of hMGL catalytic function.
Collapse
Affiliation(s)
- Ioannis Karageorgos
- Center for Drug Discovery, Northeastern University, 360 Huntington Avenue, 116 Mugar Hall, Boston, MA 02115-5000, USA 617-373-2208. Fax: +1 617-373-7493
| | - Sergiy Tyukhtenko
- Center for Drug Discovery, Northeastern University, 360 Huntington Avenue, 116 Mugar Hall, Boston, MA 02115-5000, USA 617-373-2208. Fax: +1 617-373-7493
| | - Nikolai Zvonok
- Center for Drug Discovery, Northeastern University, 360 Huntington Avenue, 116 Mugar Hall, Boston, MA 02115-5000, USA 617-373-2208. Fax: +1 617-373-7493
| | - David R. Janero
- Center for Drug Discovery, Northeastern University, 360 Huntington Avenue, 116 Mugar Hall, Boston, MA 02115-5000, USA 617-373-2208. Fax: +1 617-373-7493
| | - Christine Sallum
- Center for Drug Discovery, Northeastern University, 360 Huntington Avenue, 116 Mugar Hall, Boston, MA 02115-5000, USA 617-373-2208. Fax: +1 617-373-7493
| | - Alexandros Makriyannis
- Center for Drug Discovery, Northeastern University, 360 Huntington Avenue, 116 Mugar Hall, Boston, MA 02115-5000, USA 617-373-2208. Fax: +1 617-373-7493
| |
Collapse
|
23
|
Budney AJ, Vandrey RG, Stanger C. Intervenções farmacológica e psicossocial para os distúrbios por uso da cannabis. BRAZILIAN JOURNAL OF PSYCHIATRY 2010. [DOI: 10.1590/s1516-44462010000500008] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
OBJETIVO: A cannabis continua sendo a substância ilegal mais amplamente utilizada na maioria dos países desenvolvidos. Seu potencial aditivo foi estabelecido e a necessidade de intervenções em problemas relacionados à cannabis se tornou clara. Este artigo faz uma revisão sobre as pesquisas que avaliam os tratamentos potenciais para transtornos por uso de cannabis. MÉTODO: Uma busca nos bancos de dados de publicações identificou os estudos e revisões na literatura científica sobre as intervenções psicossociais e farmacológicas nos transtornos por uso de cannabis. RESULTADOS: Para adultos, as intervenções com base comportamental geram efeitos positivos significativos na abstinência e nas reduções no uso de cannabis. Em adolescentes, tratamentos similares e intervenções com base na família demonstraram eficácia. Entre os estudos, os índices de resposta parecem ser modestos mesmo com os mais potentes tratamentos psicossociais. As avaliações das abordagens farmacológicas para os transtornos por uso de cannabis têm ainda que fornecer dados sobre a eficácia clínica de qualquer medicação específica. Enfoques baseados em agonistas e antagonistas parecem ser os mais promissores. Os avanços na compreensão da neurobiologia do sistema canabinoide são fonte de otimismo no sentido de que a síntese de compostos que alteram o funcionamento do sítio receptor CB1 possa produzir medicações promissoras. CONCLUSÃO: As pesquisas clínicas identificaram tratamentos psicossociais eficazes, mas ainda não produziram farmacoterapias eficazes. Muitos estudos ainda têm que ser feitos para aumentar a potência e o acesso às intervenções para aqueles que buscam o tratamento para transtornos por uso de cannabis.
Collapse
|
24
|
Budney AJ, Vandrey RG, Stanger C. [Pharmacological and psychosocial interventions for cannabis use disorders]. REVISTA BRASILEIRA DE PSIQUIATRIA (SAO PAULO, BRAZIL : 1999) 2010; 32 Suppl 1:S46-55. [PMID: 20512270 PMCID: PMC3690346] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
OBJECTIVE Cannabis remains the most widely used illicit substance in most developed countries. Its addictive potential has been established and the need for interventions for cannabis-related problems has become apparent. This article provides a review of the research evaluating potential treatments for cannabis use disorders. METHOD A search of publication databases identified research studies and reviews of the scientific literature on psychosocial and pharmacological interventions for cannabis use disorders. RESULTS For adults, behaviorally-based interventions engender significant positive effects on abstinence and reductions in cannabis use. With adolescents, similar treatments and family-based interventions have demonstrated efficacy. Across studies, response rates appear modest even with the most potent psychosocial treatments. Evaluations of pharmacological approaches to cannabis use disorders have yet to provide clinical efficacy data for any specific medication. Agonist and antagonist approaches appear to offer the most promise. Advances in understanding of the neurobiology of the cannabinoid system provide optimism that the synthesis of compounds that alter CB(1) receptor site functioning may produce promising medications. CONCLUSION Clinical research has identified effective psychosocial treatments, but has yet to yield effective pharmacotherapies. Much work remains to enhance the potency of and access to interventions for those seeking treatment for cannabis use disorders.
Collapse
Affiliation(s)
- Alan J Budney
- Department of Psychiatry and Behavioral Sciences, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205, USA.
| | | | | |
Collapse
|
25
|
Hwang J, Adamson C, Butler D, Janero DR, Makriyannis A, Bahr BA. Enhancement of endocannabinoid signaling by fatty acid amide hydrolase inhibition: a neuroprotective therapeutic modality. Life Sci 2009; 86:615-23. [PMID: 19527737 DOI: 10.1016/j.lfs.2009.06.003] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2009] [Revised: 05/28/2009] [Accepted: 06/03/2009] [Indexed: 12/31/2022]
Abstract
AIMS This review posits that fatty acid amide hydrolase (FAAH) inhibition has therapeutic potential against neuropathological states including traumatic brain injury; Alzheimer's, Huntington's, and Parkinson's diseases; and stroke. MAIN METHODS This proposition is supported by data from numerous in vitro and in vivo experiments establishing metabolic and pharmacological contexts for the neuroprotective role of the endogenous cannabinoid ("endocannabinoid") system and selective FAAH inhibitors. KEY FINDINGS The systems biology of endocannabinoid signaling involves two main cannabinoid receptors, the principal endocannabinoid lipid mediators N-arachidonoylethanolamine ("anandamide") (AEA) and 2-arachidonoyl glycerol (2-AG), related metabolites, and the proteins involved in endocannabinoid biosynthesis, biotransformation, and transit. The endocannabinoid system is capable of activating distinct signaling pathways on-demand in response to pathogenic events or stimuli, thereby enhancing cell survival and promoting tissue repair. Accumulating data suggest that endocannabinoid system modulation at discrete targets is a promising pharmacotherapeutic strategy for treating various medical conditions. In particular, neuronal injury activates cannabinoid signaling in the central nervous system as an intrinsic neuroprotective response. Indirect potentiation of this salutary response through pharmacological inhibition of FAAH, an endocannabinoid-deactivating enzyme, and consequent activation of signaling pathways downstream from cannabinoid receptors have been shown to promote neuronal maintenance and function. SIGNIFICANCE This therapeutic modality has the potential to offer site- and event-specific neuroprotection under conditions where endocannabinoids are being produced as part of a physiological protective mechanism. In contrast, direct application of cannabinoid receptor agonists to the central nervous system may activate CB receptors indiscriminately and invite unwanted psychotrophic effects.
Collapse
Affiliation(s)
- Jeannie Hwang
- Department of Pharmaceutical Sciences and the Neurosciences Program, University of Connecticut, Storrs, Connecticut, USA
| | | | | | | | | | | |
Collapse
|
26
|
Tiburu EK, Tyukhtenko S, Deshmukh L, Vinogradova O, Janero DR, Makriyannis A. Structural biology of human cannabinoid receptor-2 helix 6 in membrane-mimetic environments. Biochem Biophys Res Commun 2009; 384:243-8. [PMID: 19397896 DOI: 10.1016/j.bbrc.2009.04.099] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2009] [Accepted: 04/19/2009] [Indexed: 10/20/2022]
Abstract
We detail the structure and dynamics of a synthetic peptide corresponding to transmembrane helix 6 (TMH6) of human cannabinoid receptor-2 (hCB2) in biomembrane-mimetic environments. The peptide's NMR structural biology is characterized by two alpha-helical domains bridged by a flexible, nonhelical hinge region containing a highly-conserved CWFP motif with an environmentally sensitive, Pro-based conformational switch. Buried within the peptide's flexible region, W(258) may hydrogen-bond with L(255) to help stabilize the Pro-kinked hCB2 TMH6 structure and position C(257) advantageously for interaction with agonist ligands. These characteristics of hCB2 TMH6 are potential structural features of ligand-induced hCB2 activation in vivo.
Collapse
Affiliation(s)
- Elvis K Tiburu
- Center for Drug Discovery and Department of Chemistry and Chemical Biology, Northeastern University, Boston, MA 02115-5000, USA
| | | | | | | | | | | |
Collapse
|