Regulation of Cell Surface CB2 Receptor during Human B Cell Activation and Differentiation

Castaneda, Julie Theresa; Harui, Airi; Roth, Michael D.

doi:10.1007/s11481-017-9744-7

Cited by 20 publications

(12 citation statements)

References 35 publications

(56 reference statements)

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“…In addition, polar ligands may have reduced access to intracellular receptor populations due to a reduced propensity to cross the plasma membrane in comparison with more lipophilic ligands ( Liu et al, 2011 ). Indeed, CB 2 has been reported to be expressed both at the cell surface and intracellularly ( Kleyer et al, 2012 ; Brailoiu et al, 2014 ; Castaneda et al, 2017 ), and intracellular CB 2 may be able to activate distinct signalling responses from surface CB 2 ( Brailoiu et al, 2014 ). Thus ligands that differentiate between these populations would have the potential to induce differential signalling patterns in comparison with lipophilic ligands that can interact with both surface and intracellular receptors.…”

Section: Introductionmentioning

confidence: 99%

Cannabinoid Receptor 2 Signalling Bias Elicited by 2,4,6-Trisubstituted 1,3,5-Triazines

et al. 2018

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Cannabinoid receptor 2 (CB2) is predominantly distributed in immune tissues and cells and is a promising therapeutic target for modulating inflammation. In this study we designed and synthesised a series of 2,4,6-trisubstituted 1,3,5-triazines with piperazinylalkyl or 1,2-diethoxyethane (PEG2) chains as CB2 agonists, all of which were predicted to be considerably more polar than typical cannabinoid ligands. In this series, we found that triazines containing an adamantanyl group were conducive to CB2 binding whereas those with a cyclopentyl group were not. Although the covalent attachment of a PEG2 linker to the adamantyl triazines resulted in a decrease in binding affinity, some of the ligands produced very interesting hCB2 signalling profiles. Six compounds with notable hCB2 orthosteric binding were functionally characterised in three pathways; internalisation, cyclic adenosine monophosphate (cAMP) and ERK phosphorylation (pERK). These were predominantly confirmed to be hCB2 agonists, and upon comparison to a reference ligand (CP 55,940), four compounds exhibited signalling bias. Triazines 14 (UOSD017) and 15 were biased towards internalisation over cAMP and pERK, and 7 was biased away from pERK activation relative to cAMP and internalisation. Intriguingly, the triazine with an amino-PEG2-piperazinyl linker (13 [UOSD008]) was identified to be a mixed agonist/inverse agonist, exhibiting apparent neutral antagonism in the internalisation pathway, transient inverse agonism in the cAMP pathway and weak partial agonism in the pERK pathway. Both the cAMP and pERK signalling were pertussis toxin (PTX) sensitive, implying that 13 is acting as both a weak agonist and inverse agonist at CB2 via Gαi/o. Compound 10 (UOSD015) acted as a balanced high intrinsic efficacy agonist with the potential to produce greater hCB2-mediated efficacy than reference ligand CP 55,940. As 10 includes a Boc-protected PEG2 moiety it is also a promising candidate for further modification, for example with a secondary reporter or fluorophore. The highest affinity compound in this set of relatively polar hCB2 ligands was compound 16, which acted as a slightly partial balanced agonist in comparison with CP 55,940. The ligands characterised here may therefore exhibit unique functional properties in vivo and have the potential to be valuable in the future development of CB2-directed therapeutics.

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Section: Introductionmentioning

confidence: 99%

Cannabinoid Receptor 2 Signalling Bias Elicited by 2,4,6-Trisubstituted 1,3,5-Triazines

et al. 2018

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“…In line with the cannabinoids’ effects on T cell function and development, Yuan et al demonstrated that Δ 9 -THC regulates Th1/Th2 cytokine balance in activated human T cells [ 211 ]. B cells are another immune cell population whose differentiation depends on ECS components such as CB 2 receptors [ 177 , 178 ].…”

Section: The “Immune Endocannabinoid System” In Adaptive and Innatmentioning

confidence: 99%

The Immune Endocannabinoid System of the Tumor Microenvironment

Kienzl

Kargl

Schicho

2020

IJMS

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Leukocytes are part of the tumor microenvironment (TME) and are critical determinants of tumor progression. Because of the immunoregulatory properties of cannabinoids, the endocannabinoid system (ECS) may have an important role in shaping the TME. Members of the ECS, an entity that consists of cannabinoid receptors, endocannabinoids and their synthesizing/degrading enzymes, have been associated with both tumor growth and rejection. Immune cells express cannabinoid receptors and produce endocannabinoids, thereby forming an “immune endocannabinoid system”. Although in vitro effects of exogenous cannabinoids on immune cells are well described, the role of the ECS in the TME, and hence in tumor development and immunotherapy, is still elusive. This review/opinion discusses the possibility that the “immune endocannabinoid system” can fundamentally influence tumor progression. The widespread influence of cannabinoids on immune cell functions makes the members of the ECS an interesting target that could support immunotherapy.

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“…There are also various explanations for potential dual coupling within the same cell. Signalsome subcellular compartmentalization and/or sequestration of signaling components is one example reviewed in 60 ; indeed subcellular distribution of CB2 can influence CB2 signaling patterns 6 , and CB2 seems to have a particularly unique distribution in immune cells [61][62][63] . Homologous signaling feedback upon CB2 activation which results in rapid desensitization of Gαs coupling with little or slower influence on Gαi coupling such as via differential phosphorylation by G Protein-Coupled Receptor Kinases or PKA 64-66 might assist in explaining the observed cAMP signaling profile.…”

Section: Discussionmentioning

confidence: 99%

Cannabinoid Receptor 2 (CB₂) Signals via G-alpha-s and Induces IL-6 and IL-10 Cytokine Secretion in Human Primary Leukocytes

Saroz

Kho

Glass

et al. 2019

Preprint

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Cannabinoid receptor 2 (CB2) is a promising therapeutic target for immunological modulation.There is, however, a deficit of knowledge regarding CB2 signaling and function in human primary immunocompetent cells. We applied an experimental paradigm which closely models the in situ state of human primary leukocytes (PBMC; peripheral blood mononuclear cells) to characterize activation of a number of signaling pathways in response to a CB2-selective ligand (HU308). We observed a "lag" phase of unchanged cAMP concentration prior to development of classically-expected Gαi-mediated inhibition of cAMP synthesis. Application of G protein inhibitors revealed that this apparent lag was a result of counteraction of Gαi effects by concurrent Gαs activation. Monitoring downstream signaling events, activation of p38 was mediated by Gαi whereas ERK1/2 and Akt phosphorylation were mediated by Gαi-coupled βγ.Activation of CREB integrated multiple components; Gαs and βγ mediated ~85% of the response, while ~15% was attributed to Gαi. Responses to HU308 had an important functional outcome -secretion of interleukins 6 (IL-6) and 10 (IL-10). IL-2, IL-4, IL-12, IL-13, IL-17A, MIP-1α, and TNF-α were unaffected. IL-6/IL-10 induction had a similar G protein coupling profile to CREB activation. All response potencies were consistent with that expected for HU308 acting via CB2. Additionally, signaling and functional effects were completely blocked by a CB2selective inverse agonist, giving additional evidence for CB2 involvement. This work expands the current paradigm regarding cannabinoid immunomodulation and reinforces the potential utility of CB2 ligands as immunomodulatory therapeutics.Keywords: cannabinoid receptor 2 (CB2), G protein-coupled receptor (GPCR), signaling, leukocytes, interleukin 6, interleukin 10 Significance statementCannabinoid receptor 2 (CB2) is a G protein-coupled receptor which plays a complex role in immunomodulation and is a promising target in a range of disorders with immune system involvement. However, to date the majority of the studies in this field have been performed on cell lines, rodent models, or stimulated primary cells. Here we provide a detailed account of CB2-mediated signaling in primary human immune cells under conditions which closely mimic their in vivo state. We reveal a complex signaling system involving an unprecedented CB2 signaling pathway and leading to immunomodulatory functional outcomes. This work provides not only a critical foundation impacting CB2-targeted drug discovery, but reveals important wider considerations for GPCR signaling studies and model validity.

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Regulation of Cell Surface CB2 Receptor during Human B Cell Activation and Differentiation

Cited by 20 publications

References 35 publications

Cannabinoid Receptor 2 Signalling Bias Elicited by 2,4,6-Trisubstituted 1,3,5-Triazines

Cannabinoid Receptor 2 Signalling Bias Elicited by 2,4,6-Trisubstituted 1,3,5-Triazines

The Immune Endocannabinoid System of the Tumor Microenvironment

Cannabinoid Receptor 2 (CB₂) Signals via G-alpha-s and Induces IL-6 and IL-10 Cytokine Secretion in Human Primary Leukocytes

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Regulation of Cell Surface CB2 Receptor during Human B Cell Activation and Differentiation

Cited by 20 publications

References 35 publications

Cannabinoid Receptor 2 Signalling Bias Elicited by 2,4,6-Trisubstituted 1,3,5-Triazines

Cannabinoid Receptor 2 Signalling Bias Elicited by 2,4,6-Trisubstituted 1,3,5-Triazines

The Immune Endocannabinoid System of the Tumor Microenvironment

Cannabinoid Receptor 2 (CB2) Signals via G-alpha-s and Induces IL-6 and IL-10 Cytokine Secretion in Human Primary Leukocytes

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Product

Resources

About

Cannabinoid Receptor 2 (CB₂) Signals via G-alpha-s and Induces IL-6 and IL-10 Cytokine Secretion in Human Primary Leukocytes