Cannabinoid CB1 and CB2 Receptor Signaling and Bias.
Ontology highlight
ABSTRACT:
SUBMITTER: Ibsen MS
PROVIDER: S-EPMC5436336 | biostudies-literature | 2017
REPOSITORIES: biostudies-literature
Publications
Cannabinoid CB<sub>1</sub> and CB<sub>2</sub> Receptor Signaling and Bias.
Ibsen Mikkel Søes MS Connor Mark M Glass Michelle M
Cannabis and cannabinoid research 20170301 1
An agonist that acts through a single receptor can activate numerous signaling pathways. Recent studies have suggested that different ligands can differentially activate these pathways by stabilizing a limited range of receptor conformations, which in turn preferentially drive different downstream signaling cascades. This concept, termed "biased signaling" represents an exciting therapeutic opportunity to target specific pathways that elicit only desired effects, while avoiding undesired effects ...[more]
Similar Datasets
Project description:Signaling through integral membrane G protein-coupled receptors (GPCRs) is influenced by lipid composition of cell membranes. By using novel high affinity ligands of human cannabinoid receptor CB2, we demonstrate that cholesterol increases basal activation levels of the receptor and alters the pharmacological categorization of these ligands. Our results revealed that (2-(6-chloro-2-((2,2,3,3-tetramethylcyclopropane-1-carbonyl)imino)benzo[d]thiazol-3(2H)-yl)ethyl acetate ligand (MRI-2646) acts as a partial agonist of CB2 in membranes devoid of cholesterol and as a neutral antagonist or a partial inverse agonist in cholesterol-containing membranes. The differential effects of a specific ligand on activation of CB2 in different types of membranes may have implications for screening of drug candidates in a search of modulators of GPCR activity. MD simulation suggests that cholesterol exerts an allosteric effect on the intracellular regions of the receptor that interact with the G-protein complex thereby altering the recruitment of G protein.
| S-EPMC7881127 | biostudies-literature
Project description:Background and purposeBiased agonism describes the ability of ligands to differentially regulate multiple signalling pathways when coupled to a single receptor. Signalling is affected by rapid agonist-induced receptor internalisation. Hence, the conventional use of equilibrium models may not be optimal, because (i) receptor numbers vary with time and, in addition, (ii) some pathways may show non-monotonic profiles over time.Experimental approachData were available from internalisation, cAMP inhibition and phosphorylation of ERK (pERK) of the cannabinoid-1 (CB1 ) receptor using a concentration series of six CB1 ligands (CP55,940, WIN55,212-2, anandamide, 2-arachidonylglycerol, Δ9 -tetrahydrocannabinol and BAY59,3074). The joint kinetic model of CB1 signalling was developed to simultaneously describe the time-dependent activities in three signalling pathways. Based on the insights from the kinetic model, fingerprint profiles of CB1 ligand bias were constructed and visualised.Key resultsA joint kinetic model was able to capture the signalling profiles across all pathways for the CB1 receptor simultaneously for a system that was not at equilibrium. WIN55,212-2 had a similar pattern as 2-arachidonylglycerol (reference). The other agonists displayed bias towards internalisation compared to cAMP inhibition. However, only Δ9 -tetrahydrocannabinol and BAY59,3074 demonstrated bias in the pERK-cAMP pathway comparison. Furthermore, all the agonists exhibited little preference between internalisation and pERK.Conclusion and implicationsThis is the first joint kinetic assessment of biased agonism at a GPCR (e.g. CB1 receptor) under non-equilibrium conditions. Kinetic modelling is a natural method to handle time-varying data when traditional equilibria are not present and enables quantification of ligand bias.
| S-EPMC7369624 | biostudies-literature
Project description:Blockade of cannabinoid type 1 (CB1)-receptor signaling decreases the rewarding properties of many drugs of abuse and has been proposed as an anti-addiction strategy. However, psychiatric side-effects limit the clinical potential of orthosteric CB1 antagonists. Negative allosteric modulators (NAMs) represent a novel and indirect approach to attenuate CB1 signaling by decreasing affinity and/or efficacy of CB1 ligands. We hypothesized that a CB1-NAM would block opioid reward while avoiding the unwanted effects of orthosteric CB1 antagonists. GAT358, a CB1-NAM, failed to elicit cardinal signs of direct CB1 activation or inactivation when administered by itself. GAT358 decreased catalepsy and hypothermia but not antinociception produced by the orthosteric CB1 agonist CP55,940, suggesting that a CB1-NAM blocked cardinal signs of CB1 activation. Next, GAT358 was evaluated using in vivo assays of opioid-induced dopamine release and reward in male rodents. In the nucleus accumbens shell, a key component of the mesocorticolimbic reward pathway, morphine increased electrically-evoked dopamine efflux and this effect was blocked by a dose of GAT358 that lacked intrinsic effects on evoked dopamine efflux. Moreover, GAT358 blocked morphine-induced reward in a conditioned place preference (CPP) assay without producing reward or aversion alone. GAT358-induced blockade of morphine CPP was also occluded by GAT229, a CB1 positive allosteric modulator (CB1-PAM), and absent in CB1-knockout mice. Finally, GAT358 also reduced oral oxycodone (but not water) consumption in a two-bottle choice paradigm. Our results support the therapeutic potential of CB1-NAMs as novel drug candidates aimed at preventing opioid reward and treating opioid abuse while avoiding unwanted side-effects.
| S-EPMC9948526 | biostudies-literature
Project description:Background and purposeCannabichromene (CBC) is one of the most abundant phytocannabinoids in Cannabis spp. It has modest antinociceptive and anti-inflammatory effects and potentiates some effects of Δ9 -tetrahydrocannabinol in vivo. How CBC exerts these effects is poorly defined and there is little information about its efficacy at cannabinoid receptors. We sought to determine the functional activity of CBC at cannabinoid CB1 and CB2 receptors.Experimental approachAtT20 cells stably expressing haemagglutinin-tagged human CB1 and CB2 receptors were used. Assays of cellular membrane potential and loss of cell surface receptors were performed.Key resultsCBC activated CB2 but not CB1 receptors to produce hyperpolarization of AtT20 cells. This activation was inhibited by a CB2 receptor antagonist AM630, and sensitive to Pertussis toxin. Application of CBC reduced activation of CB2 , but not CB1 , receptors by subsequent co-application of CP55,940, an efficacious CB1 and CB2 receptor agonist. Continuous CBC application induced loss of cell surface CB2 receptors and desensitization of the CB2 receptor-induced hyperpolarization.Conclusions and implicationsCBC is a selective CB2 receptor agonist displaying higher efficacy than tetrahydrocannabinol in hyperpolarizing AtT20 cells. CBC can also recruit CB2 receptor regulatory mechanisms. CBC may contribute to the potential therapeutic effectiveness of some cannabis preparations, potentially through CB2 receptor-mediated modulation of inflammation.
| S-EPMC6932936 | biostudies-literature
Project description:Background: The endocannabinoid system is present in multiple organ systems and is involved in smooth muscle regulation, immune function, neuroendocrine modulation, and metabolism of tissues. Limited data are available regarding the presence and role of this system in reproductive tissues. Components of the endocannabinoid system have been identified in myometrial and placental tissues. However, no study has investigated differential expression of the endocannabinoid system in labor. Objectives: The purpose of this study was to identify and quantify two components of the endocannabinoid system, the CB1 cannabinoid receptor and cannabinoid receptor interacting protein 1a (CRIP1a) in uterine and placental tissues, and to determine if there is differential expression in tissues exposed to labor. We hypothesized that CB1 cannabinoid receptor concentration would be altered in uterine and placental tissue exposed to labor compared with tissues not exposed to labor. Study Design: Uterine and placental tissue samples were collected in nine laboring and 11 nonlaboring women undergoing cesarean delivery. CB1 cannabinoid receptor and CRIP1a presence and quantification were evaluated using western blot, immunohistochemistry, and real-time quantitative polymerase chain reaction. Statistical comparisons of laboring and nonlaboring subjects were made for uterine and placental tissue using a Mann-Whitney test. Results: Immunohistochemistry demonstrated positive staining for CB1 cannabinoid receptors and CRIP1a in uterine tissue. The protein abundance of CB1 cannabinoid receptor in uterine tissue was significantly lower in tissues exposed to labor (p=0.01). The protein abundance of CRIP1a was lower in uterine tissue exposed to labor but did not reach statistical significance (p=0.06). mRNA expression of CB1 cannabinoid receptor (p=0.20) and CRIP1a (p=0.63) did not differ in labored compared with nonlabored uterine tissues. Conclusions: Our findings of diminished protein density of CB1 cannabinoid receptor in uterine tissue exposed to labor support the hypothesis that the endocannabinoid system plays a role in parturition. Our data add to the growing body of evidence indicating the endocannabinoid system is of importance for successful reproduction and support the need for additional research investigating this complex system as it pertains to labor. ClinicalTrials.gov ID: NCT03752021.
| S-EPMC9225407 | biostudies-literature
Project description:Cannabinoid CB2 receptor (CB2R) agonists are investigated as therapeutic agents in the clinic. However, their molecular mode-of-action is not fully understood. Here, we report the discovery of LEI-102, a CB2R agonist, used in conjunction with three other CBR ligands (APD371, HU308, and CP55,940) to investigate the selective CB2R activation by binding kinetics, site-directed mutagenesis, and cryo-EM studies. We identify key residues for CB2R activation. Highly lipophilic HU308 and the endocannabinoids, but not the more polar LEI-102, APD371, and CP55,940, reach the binding pocket through a membrane channel in TM1-TM7. Favorable physico-chemical properties of LEI-102 enable oral efficacy in a chemotherapy-induced nephropathy model. This study delineates the molecular mechanism of CB2R activation by selective agonists and highlights the role of lipophilicity in CB2R engagement. This may have implications for GPCR drug design and sheds light on their activation by endogenous ligands.
| S-EPMC10017709 | biostudies-literature
Project description:Introduction: Overdose fatalities associated with the opioid epidemic are predictably attributable to drug-induced respiratory depression. In terms of illicit opioid abuse, fentanyl is the synthetic opioid responsible for the largest number of overdose deaths. There is, therefore, an urgent need to identify safe and effective therapeutics that can attenuate fentanyl-induced respiratory depression. Identification of effective alternate analgesic strategies that lessen the respiratory depression associated with narcotics would also help improve current strategies for pain management. Our laboratory recently reported that the G protein-biased CB2 cannabinoid receptor agonist LY2828360 suppressed chemotherapy-induced neuropathic nociception and attenuated both morphine tolerance and physical dependence in paclitaxel-treated mice. However, the impact of LY2828360 on other undesirable side effects of opioids, such as opioid-induced respiratory depression, remains unknown. Materials and Methods: We used whole-body plethysmography to assess the impact of the CB2 cannabinoid agonist LY2828360 on fentanyl-induced respiratory depression using wild-type (WT) and CB2 knockout (CB2KO) mice. Results: Fentanyl reduced minute ventilation and respiratory frequency without altering tidal volume in both WT and CB2KO mice. In WT mice, the high dose of fentanyl (0.2 mg/kg intraperitoneal [i.p.]) produced a greater suppression of respiratory parameters compared with the low dose of fentanyl (0.1 mg/kg i.p.). Coadministration of a behaviorally active dose of LY2828360 (3 mg/kg i.p.) with fentanyl (0.2 mg/kg i.p.) attenuated fentanyl-induced respiratory depression in WT mice. Notably, LY2828360 (3 mg/kg i.p.) did not attenuate fentanyl-induced respiratory depression in CB2KO mice, consistent with mediation by CB2 receptors. Moreover, LY2828360 (3 mg/kg i.p.) alone lacked intrinsic effects on respiratory parameters in either WT or CB2KO mice. Conclusion: The combination of a CB2 agonist with fentanyl may represent a safer adjunctive therapeutic strategy compared with a narcotic analgesic alone by attenuating the development of opioid-induced respiratory depression. Moreover, the CB2 agonist, administered alone, did not alter respiration. Our findings suggest that the CB2 cannabinoid agonist LY2828360 may provide CB2-mediated protection against fentanyl-induced respiratory depression, a detrimental and unwanted side effect of opioid use and abuse.
| S-EPMC8612411 | biostudies-literature
Project description:The cannabinoid receptor 1 (CB1) is the principal target of the psychoactive constituent of marijuana, the partial agonist Δ9-tetrahydrocannabinol (Δ9-THC). Here we report two agonist-bound crystal structures of human CB1 in complex with a tetrahydrocannabinol (AM11542) and a hexahydrocannabinol (AM841) at 2.80 Å and 2.95 Å resolution, respectively. The two CB1-agonist complexes reveal important conformational changes in the overall structure, relative to the antagonist-bound state, including a 53% reduction in the volume of the ligand-binding pocket and an increase in the surface area of the G-protein-binding region. In addition, a 'twin toggle switch' of Phe2003.36 and Trp3566.48 (superscripts denote Ballesteros-Weinstein numbering) is experimentally observed and appears to be essential for receptor activation. The structures reveal important insights into the activation mechanism of CB1 and provide a molecular basis for predicting the binding modes of Δ9-THC, and endogenous and synthetic cannabinoids. The plasticity of the binding pocket of CB1 seems to be a common feature among certain class A G-protein-coupled receptors. These findings should inspire the design of chemically diverse ligands with distinct pharmacological properties.
| S-EPMC5793864 | biostudies-literature
Project description:Single chemical entities with potential to simultaneously interact with two binding sites are emerging strategies in medicinal chemistry. We have designed, synthesized and functionally characterized the first bitopic ligands for the CB2 receptor. These compounds selectively target CB2 versus CB1 receptors. Their binding mode was studied by molecular dynamic simulations and site-directed mutagenesis.
| S-EPMC7756656 | biostudies-literature
Project description:Background and purposeArrestin or G protein bias may be desirable for novel cannabinoid therapeutics. Arrestin-2 and arrestin-3 translocation to CB1 receptor have been suggested to mediate different functions that may be exploited with biased ligands. Here, the requirement of a recently described phosphorylation motif 'pxxp' (where 'p' denotes phosphorylatable serine or threonine and 'x' denotes any other amino acid) within the CB1 receptor C-terminus for interaction with different arrestin subtypes was examined.Experimental approachSite-directed mutagenesis was conducted to generate nine different phosphorylation-impaired CB1 receptor C-terminal mutants. Bioluminescence resonance energy transfer (BRET) was employed to measure arrestin-2/3 translocation and G protein dissociation of a high efficacy agonist for each mutant. Immunocytochemistry was used to quantify receptor expression.Key resultsThe effects of each mutation were shared for arrestin-2 and arrestin-3 translocation to CB1 receptor pxxp motifs are partially required for arrestin-2/3 translocation, but translocation was not completely inhibited until all phosphorylation sites were mutated. The rate of arrestin translocation was reduced with simultaneous mutation of S425 and S429. Desensitisation of G protein dissociation was inhibited in different mutants proportional to the extent of their respective loss of arrestin translocation.Conclusions and implicationsThese data do not support the existence of an 'essential' pxxp motif for arrestin translocation to CB1 receptor. These data also identify that arrestin-2 and arrestin-3 have equivalent phosphorylation requirements within the CB1 receptor C-terminus, suggesting arrestin subtype-selective biased ligands may not be viable and that different regions of the C-terminus contribute differently to arrestin translocation.
| S-EPMC10100024 | biostudies-literature