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2-arachnadoyl glycerol (2-AG) is one of the most common endocannabinoid molecules with anti-proliferative, cytotoxic, and pro-proliferative effects on different types of tumors. Typically, it induces cell death via cannabinoid receptor 1/2 (CB1/CB2)-linked ceramide production. In breast cancer, ceramide is counterbalanced by the sphingosine-1-phosphate, and thus the mechanisms of 2-AG influence on proliferation are poorly understood. We evaluated the mechanism of the anti-proliferative action by 2-AG and the influence of lysophaosphatidylinositol (LPI) on it in six human breast cancer cell lines of different tumor degree (MCF-10A, MCF-7, BT-474, BT-20, SK-BR-3, and MDA-MB-231) using resazurin test, inhibitor, blocker, and anti-oxidant analysis, and siRNA interference. To avoid acyl migration in 2-AG, we replaced it with the analog 2-arachidonoyl-1,3-difluoropropanol (2-ADFP) newly synthesized by us. Using a molecular docking approach, we showed that at the CB2 receptor, 2-ADFP and 2-AG were very close to each other. However, 2-ADFP demonstrated a stronger affinity towards CB1 in the antagonist-bound conformation. 2-ADFP was anti-proliferative in all the cell lines tested. The toxicity of 2-ADFP was enhanced by LPI. 2-ADFP activity was reduced or prevented by the CB2 and vanilloid receptor 1 (TRPV1) blockers, inositol triphosphate receptor, CREB, and cyclooxygenase 2 inhibitor, and by anti-oxidant addition. Together with the literature data, these results indicate CB2- and TRPV1-dependent COX-2 induction with concomitant cell death induction by the oxidized molecule's metabolites.

Aims: Renal fibrosis is a common feature in various chronic kidney diseases (CKD). Tubular cell damage is a main characterization which results from dysregulated fatty acid oxidation (FAO) and lipid accumulation. Cannabinoid Receptor 2 (CB2) contributes to renal fibrosis, however, its role in FAO dysregulation in tubular cells is not clarified. In this study, we found CB2 plays a detrimental role in lipid metabolism in tubular cells., Methods: CB2 knockout mice were adopted to establish a folic acid-induced nephropathy (FAN) model. CB2-induced FAO dysfunction, lipid deposition, and fibrogenesis were assessed in vivo and vitro. To explore molecular mechanisms, β-catenin inhibitors and peroxisome proliferator-activated receptor alpha (PPARα) activators were also used in CB2-overexpressed cells. The mediative role of β-catenin in CB2-inhibited PPARα and peroxisome proliferator-activated receptor gamma coactivator-1 alpha (PGC-1α) activation was analyzed., Results: CB2 activates β-catenin signaling, resulting in the suppression of PPARα/PGC-1α axis. This decreased FAO functions and led to lipid droplet formation in tubular cells. CB2 gene ablation effectively mitigated FAO dysfunction, lipid deposition and uremic toxins accumulation in FAN mice, consequently retarding renal fibrosis. Additionally, inhibition to β-catenin or PPARα activation could greatly inhibit lipid accumulation and fibrogenesis induced by CB2., Conclusions: This study highlights CB2 disrupts FAO in tubular cells through β-catenin activation and subsequent inhibition on PPARα/PGC-1α activity. Targeted inhibition on CB2 offers a perspective therapeutic strategy to fight against renal fibrosis., Competing Interests: Declaration of competing interest The authors have no conflict of interests in this paper., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Introduction: Cannabichromene (CBC) is a minor constituent of cannabis that is a selective cannabinoid CB2 receptor agonist and activator of TRPA1. To date, it has not been shown whether (-)-CBC, (+)-CBC, or both can mediate these effects. In this study, we investigate the activity of the CBC enantiomers at CB1, CB2, and Transient receptor potential ankyrin 1 (TRPA1) receptors in vitro . Materials and Methods: CBC enantiomers were purified from synthetic CBC by chiral chromatography, and their optical activity was confirmed by spectroscopy. Human CB1 and CB2 receptor activity was measured using a fluorescent assay of membrane potential in stably transfected AtT20 cells. TRPA1 activation was measured using a fluorescent assay of intracellular calcium in stably transfected HEK293 cells. Results: The (-)-CBC activated CB2 with an EC 50 of 1.5 µM, to a maximum of 60% of (-)CP55940. (+)-CBC did not activate CB2 at concentrations up to 30 µM. Only 30 µM (-)-CBC produced detectable activation of CB1, (+)-CBC was inactive. Both (-)-CBC and (+)-CBC activated TRPA1; at 30 µM (-)-CBC produced an activation 50% of that of the reference agonist cinnamaldehyde (300 µM), 30 µM (+)-CBC activated TRPA1 to 38% of the cinnamaldehyde maximum. Discussion: It is unclear whether (-)-CBC is the sole or even the predominant enantiomer of CBC enzymatically synthesized in cannabis. This study shows that (-)-CBC is the active isomer at CB2 receptors, while both isomers activate TRPA1. The results suggest that medicinal preparations of CBC that target cannabinoid receptors would be most effective when (-)-CBC is the dominant isomer.

Development of type 2 diabetes mellitus (T2DM) is associated with low-grade chronic type 2 inflammation and disturbance of glucose homeostasis. Group 2 innate lymphoid cells (ILC2s) play a critical role in maintaining adipose homeostasis via the production of type 2 cytokines. Here, we demonstrate that CB 2 , a G-protein-coupled receptor (GPCR) and member of the endocannabinoid system, is expressed on both visceral adipose tissue (VAT)-derived murine and human ILC2s. Moreover, we utilize a combination of ex vivo and in vivo approaches to explore the functional and therapeutic impacts of CB 2 engagement on VAT ILC2s in a T2DM model. Our results show that CB 2 stimulation of ILC2s protects against insulin-resistance onset, ameliorates glucose tolerance, and reverses established insulin resistance. Our mechanistic studies reveal that the therapeutic effects of CB 2 are mediated through activation of the AKT, ERK1/2, and CREB pathways on ILC2s. The results reveal that the CB 2 agonist can serve as a candidate for the prevention and treatment of T2DM., Competing Interests: Declaration of interests The authors declare no competing interests., (Copyright © 2024 The Author(s). Published by Elsevier Inc. All rights reserved.)

Background and Purpose: Receptor activity-modifying proteins (RAMPs) and melanocortin receptor accessory proteins (MRAPs) modulate expression and signalling of calcitonin and melanocortin GPCRs. Interactions with other GPCRs have also been reported. The cannabinoid receptors, CB 1 and CB 2 , and two putative cannabinoid receptors, GPR18 and GPR55, exhibit substantial intracellular expression and there are discrepancies in ligand responsiveness between studies. We investigated whether interactions with RAMPs or MRAPs could explain these phenomena., Experimental Approach: Receptors and accessory proteins were co-expressed in HEK-293 cells. Selected receptors were studied at basal expression levels and also with enhanced expression produced by incorporation of a preprolactin signal sequence/peptide (pplss). Cell surface and total expression of receptors and accessory proteins were quantified using immunocytochemistry. Signalling was measured using cAMP (CAMYEL) and G protein dissociation (TRUPATH Gα 13 ) biosensors., Key Results: MRAP2 enhanced surface and total expression of GPR18. Pplss-GPR18 increased detection of cell surface MRAP2. MRAP1α and MRAP2 reduced GPR55 surface and total expression, correlating with reduced constitutive, but not agonist-induced, signalling. GPR55, pplss-CB 1 and CB 2 reduced detection of MRAP1α at the cell surface. Pplss-CB 1 agonist potency was reduced by MRAP2 in Gα 13 but not cAMP assays, consistent with MRAP2 reducing pplss-CB 1 expression. Some cannabinoid receptors increased RAMP2 or RAMP3 total expression without influencing surface expression., Conclusions and Implications: Mutual influences on expression and/or function for specific accessory protein-receptor pairings raises the strong potential for physiological and disease-relevant consequences. Sequestration and/or hetero-oligomerisation of cannabinoid receptors with accessory proteins is a possible novel mechanism for receptor crosstalk., Linked Articles: This article is part of a themed issue Therapeutic Targeting of G Protein-Coupled Receptors: hot topics from the Australasian Society of Clinical and Experimental Pharmacologists and Toxicologists 2021 Virtual Annual Scientific Meeting. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v181.14/issuetoc., (© 2023 The Authors. British Journal of Pharmacology published by John Wiley & Sons Ltd on behalf of British Pharmacological Society.)

Cannabinoid CB 2 agonists show therapeutic efficacy without unwanted CB 1 -mediated side effects. The G protein-biased CB 2 receptor agonist LY2828360 attenuates the maintenance of chemotherapy-induced neuropathic nociception in male mice and blocks development of morphine tolerance in this model. However, the cell types involved in this phenomenon are unknown and whether this therapeutic profile is observed in female mice has never been investigated. We used conditional deletion of CB 2 receptors to determine the cell population(s) mediating the anti-allodynic and morphine-sparing effects of CB 2 agonists. Anti-allodynic effects of structurally distinct CB 2 agonists (LY2828360 and AM1710) were present in paclitaxel-treated CB 2 f/f mice and in mice lacking CB 2 receptors in CX3CR1 expressing microglia/macrophages (CX3CR1 CRE/+ ; CB 2 f/f ), but were absent in mice lacking CB 2 receptors in peripheral sensory neurons (Advillin CRE/+ ; CB 2 f/f ). The morphine-sparing effect of LY28282360 occurred in a sexually-dimorphic manner, being present in male, but not female, mice. LY2828360 treatment (3 mg/kg per day i.p. x 12 days) blocked the development of morphine tolerance in male CB 2 f/f and CX3CR1 CRE/+ ; CB 2 f/f mice with established paclitaxel-induced neuropathy but was absent in male (or female) Advillin CRE/+ ; CB 2 f/f mice. Co-administration of morphine with a low dose of LY2828360 (0.1 mg/kg per day i.p. x 6 days) reversed morphine tolerance in paclitaxel-treated male CB 2 f/f mice, but not Advillin CRE/+ ; CB 2 f/f mice of either sex. LY2828360 (3 mg/kg per day i.p. x 8 days) delayed, but did not prevent, the development of paclitaxel-induced mechanical or cold allodynia in either CB 2 f/f or CX3CR1 CRE/+ ; CB 2 f/f mice of either sex. Our findings have potential clinical implications., Competing Interests: Declaration of Competing Interest The authors have no financial/personal interest or belief that could affect the objectivity of this manuscript. Dr. Hohmann is a consultant for Anagin Inc., (Copyright © 2024 The Authors. Published by Elsevier Masson SAS.. All rights reserved.)

We tested the efficacy of 4'-fluorocannabidiol (4'-F-CBD), a semisynthetic cannabidiol derivative, and HU-910, a cannabinoid receptor 2 (CB2) agonist in resolving l-DOPA-induced dyskinesia (LID). Specifically, we were interested in studying whether these compounds could restrain striatal inflammatory responses and rescue glutamatergic disturbances characteristic of the dyskinetic state. C57BL/6 mice were rendered hemiparkinsonian by unilateral striatal lesioning with 6-OHDA. Abnormal involuntary movements were then induced by repeated i.p. injections of l-DOPA + benserazide. After LID was installed, the effects of a 3-day treatment with 4'-F-CBD or HU-910 in combination or not with the TRPV1 antagonist capsazepine (CPZ) or CB2 agonists HU-308 and JWH015 were assessed. Immunostaining was conducted to investigate the impacts of 4'-F-CBD and HU-910 (with CPZ) on inflammation and glutamatergic synapses. Our results showed that the combination of 4'-F-CBD + CPZ, but not when administered alone, decreased LID. Neither HU-910 alone nor HU-910+CPZ were effective. The CB2 agonists HU-308 and JWH015 were also ineffective in decreasing LID. Both combination treatments efficiently reduced microglial and astrocyte activation in the dorsal striatum of dyskinetic mice. However, only 4'-F-CBD + CPZ normalized the density of glutamate vesicular transporter-1 (vGluT1) puncta colocalized with the postsynaptic density marker PSD95. These findings suggest that 4'-F-CBD + CPZ normalizes dysregulated cortico-striatal glutamatergic inputs, which could be involved in their anti-dyskinetic effects. Although it is not possible to rule out the involvement of anti-inflammatory mechanisms, the decrease in striatal neuroinflammation markers by 4'-F-CBD and HU-910 without an associated reduction in LID indicates that they are insufficient per se to prevent LID manifestations., Competing Interests: Declaration of competing interest Francisco S. Guimarães is a co-inventor of the patent “Fluorinated CBD compounds, compositions and uses thereof. Pub. No.: WO/2014/108899. International Application No.: PCT/IL 2014/050023″ Def. US no. Reg. 62193296; July 29, 2015; INPI on August 19, 2015 (BR1120150164927). The University of São Paulo has licensed the patent to Phytecs Pharm (USP Resolution No. 15.1.130002.1.1). The University of São Paulo has an agreement with Prati-Donaduzzi (Toledo, Brazil) to “develop a pharmaceutical product containing synthetic cannabidiol and prove its safety and therapeutic efficacy in the treatment of epilepsy, schizophrenia, Parkinson's disease, and anxiety disorders.” The other authors declare no competing interests., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Taking into account homeostatic disorders resulting from arterial hypertension and the key importance of CacyBP/SIP, β-catenin and endocannabinoids in the functioning of many organs, it was decided to assess the presence and distribution of CacyBP/SIP, β-catenin, CB1 and CB2 in the adrenal glands of hypertensive rats of various aetiology. The study was conducted on the adrenal glands of rats with spontaneous and renovascular hypertension. The expression of CacyBP/SIP, β-catenin, CB1 and CB2 was detected by immunohistochemistry and real-time PCR method. The results of the present study revealed both lower gene expression and immunoreactivity of CacyBP/SIP in the adrenal glands of all hypertensive groups compared to the normotensive rats. This study demonstrated a reduction in the immunoreactivity and expression of the β-catenin, CB1 and CB2 genes in the adrenals of 2K1C rats. While in SHR, the reaction showing β-catenin and CB1 was very weak or negative, and the expression of CB2 in the adrenal glands of these rats increased. The results of this study show, for the first time, marked differences in the expression of CacyBP/SIP, β-catenin and CB1 and CB2 cannabinoid receptors in the adrenal glands of rats with primary (SHR) and secondary hypertension (2K1C)., (© 2024 The Authors. Journal of Cellular and Molecular Medicine published by Foundation for Cellular and Molecular Medicine and John Wiley & Sons Ltd.)

Early adversity, the loss of the inhibitory GABAergic interneuron parvalbumin, and elevated neuroinflammation are associated with depression. Individuals with a maltreatment history initiate medicinal cannabis use earlier in life than non-maltreated individuals, suggesting self-medication. Female rats underwent maternal separation (MS) between 2 and 20 days of age to model early adversity or served as colony controls. The prelimbic cortex and behavior were examined to determine whether MS alters the cannabinoid receptor 2 (CB2), which has anti-inflammatory properties. A reduction in the CB2-associated regulatory enzyme MARCH7 leading to increased NLRP3 was observed with Western immunoblots in MS females. Immunohistochemistry with stereology quantified numbers of parvalbumin-immunoreactive cells and CB2 at 25, 40, and 100 days of age, revealing that the CB2 receptor associated with PV neurons initially increases at P25 and subsequently decreases by P40 in MS animals, with no change in controls. Confocal and triple-label microscopy suggest colocalization of these CB2 receptors to microglia wrapped around the parvalbumin neuron. Depressive-like behavior in MS animals was elevated at P40 and reduced with the CB2 agonist HU-308 or a CB2-overexpressing lentivirus microinjected into the prelimbic cortex. These results suggest that increasing CB2 expression by P40 in the prelimbic cortex prevents depressive behavior in MS female rats.

To test the hypothesis that genetic and pharmacological modulation of the classical cannabinoid type 1 (CB 1 ) and 2 (CB 2 ) receptors attenuate cancer-induced bone pain, we searched Medline, Web of Science and Scopus for relevant skeletal and non-skeletal cancer studies from inception to July 28, 2022. We identified 29 animal and 35 human studies. In mice, a meta-analysis of pooled studies showed that treatment of osteolysis-bearing males with the endocannabinoids AEA and 2-AG (mean difference [MD] - 24.83, 95% confidence interval [ 95% CI] - 34.89, - 14.76, p < 0.00001) or the synthetic cannabinoid (CB) agonists ACPA, WIN55,212-2, CP55,940 (CB 1/2 -non-selective) and AM1241 (CB 2 -selective) (MD - 28.73, 95% CI - 45.43, - 12.02, p = 0.0008) are associated with significant reduction in paw withdrawal frequency. Consistently, the synthetic agonists AM1241 and JWH015 (CB 2 -selective) increased paw withdrawal threshold (MD 0.89, 95% CI 0.79, 0.99, p < 0.00001), and ACEA (CB 1 -selective), AM1241 and JWH015 (CB 2 -selective) reduced spontaneous flinches (MD - 4.85, 95% CI - 6.74, - 2.96, p < 0. 00001) in osteolysis-bearing male mice. In rats, significant increase in paw withdrawal threshold is associated with the administration of ACEA and WIN55,212-2 (CB 1/2 -non-selective), JWH015 and AM1241 (CB 2 -selective) in osteolysis-bearing females (MD 8.18, 95% CI 6.14, 10.21, p < 0.00001), and treatment with AM1241 (CB 2 -selective) increased paw withdrawal thermal latency in males (mean difference [MD]: 3.94, 95% CI 2.13, 5.75, p < 0.0001), confirming the analgesic capabilities of CB 1/2 ligands in rodents. In human, treatment of cancer patients with medical cannabis (standardized MD - 0.19, 95% CI - 0.35, - 0.02, p = 0.03) and the plant-derived delta-9-THC (20 mg) (MD 3.29, CI 2.24, 4.33, p < 0.00001) or its synthetic derivative NIB (4 mg) (MD 2.55, 95% CI 1.58, 3.51, p < 0.00001) are associated with reduction in pain intensity. Bioinformatics validation of KEGG, GO and MPO pathway, function and process enrichment analysis of mouse, rat and human data revealed that CB 1 and CB 2 receptors are enriched in a cocktail of nociceptive and sensory perception, inflammatory, immune-modulatory, and cancer pathways. Thus, we cautiously conclude that pharmacological modulators of CB 1/2 receptors show promise in the treatment of cancer-induced bone pain, however further assessment of their effects on bone pain in genetically engineered animal models and cancer patients is warranted., (© 2024. The Author(s).)

Endocannabinoid anandamide (AEA) and paracannabinoid lysophosphatidylinositol (LPI) play a significant role in cancer cell proliferation regulation. While anandamide inhibits the proliferation of cancer cells, LPI is known as a cancer stimulant. Despite the known endocannabinoid receptor crosstalk and simultaneous presence in the cancer microenvironment of both molecules, their combined activity has never been studied. We evaluated the effect of LPI on the AEA activity in six human breast cancer cell lines of different carcinogenicity (MCF-10A, MCF-7, BT-474, BT-20, SK-BR-3, MDA-MB-231) using resazurin and LDH tests after a 72 h incubation. AEA exerted both anti-proliferative and cytotoxic activity with EC 50 in the range from 31 to 80 µM. LPI did not significantly affect the cell viability. Depending on the cell line, the response to the LPI-AEA combination varied from a decrease in AEA cytotoxicity to an increase in it. Based on the inhibitor analysis of the endocannabinoid receptor panel, we showed that for the former effect, an active GPR18 receptor was required and for the latter, an active CB2 receptor. The data obtained for the first time are important for the understanding the manner by which endocannabinoid receptor ligands acting simultaneously can modulate cancer growth at different stages.

Background: Preclinical and clinical evidence suggests that cannabis has potential analgesic properties. However, cannabinoid receptor expression and localization within spinal cord pain processing circuits remain to be characterized across sex and species., Aims: We aimed to investigate the differential expression of the cannabinoid type 1 (CB1) receptor across dorsal horn laminae and cell populations in male and female adult rats and humans., Methods: To investigate and quantify CB1 receptor expression in the spinal dorsal horn across species, we refined immunohistochemical procedures for successful rat and human fixed tissue staining and confocal imaging. Immunohistochemical results were complemented with analysis of CB1 gene ( CNR1 ) expression within rodent and human dorsal horn using single-cell/nuclei RNA sequencing data sets., Results: We found that CB1 was preferentially localized to the neuropil within the superficial dorsal horn of both rats and humans, with CB1 somatic staining across dorsal horn laminae. CB1 receptor immunoreactivity was significantly higher in the superficial dorsal horn compared to the deeper dorsal horn laminae for both rats and humans, which was conserved across sex. Interestingly, we found that CB1 immunoreactivity was not primarily localized to peptidergic afferents in rats and humans and that CNR1 (CB1) but not CNR2 (CB2) was robustly expressed in dorsal horn neuron subpopulations of both rodents and humans., Conclusions: The conserved preferential expression of CB1 receptors in the superficial dorsal horn in male and female rodents and humans has significant implications for understanding the roles of this cannabinoid receptor in spinal mechanisms of nociception and analgesia., Competing Interests: Michael Hildebrand has received consulting/speaker fees and/or arms research funding from AnaBios Incorporated, Eli Lilly, Grunenthal, and Vertex Pharmaceuticals but with no direct relationship or conflict of interest relating to the present published research article. All other authors have no conflicts of interest to report., (© 2023 The Author(s). Published with license by Taylor & Francis Group, LLC.)

Endometriosis, a chronic condition affecting around 10-14% of women, is challenging to manage, due to its complex pathogenesis and limited treatment options. Research has suggested a potential role of the gut microbiota and the endocannabinoid system in the development and progression of endometriosis. This narrative review aims to explore the role of, and any potential interactions between, the endocannabinoid system (ECS) and the gut microbiota in endometriosis. This review found that both the ECS and microbiota influence endometriosis, with the former regulating inflammation and pain perception and the latter influencing immune responses and hormonal balance. There is evidence that a dysregulation of the endocannabinoid system and the gut microbiota influence endometriosis symptoms and progression via changes in CB1 receptor expression and increased circulating levels of endocannabinoids. Microbial imbalances in the gut, such as increases in Prevotella , have been directly correlated to increased bloating, a common endometriosis symptom, while increases in E. coli have supported the bacterial contamination hypothesis as a potential pathway for endometriosis pathogenesis. These microbial imbalances have been correlated with increases in inflammatory markers such as TNF-α and IL-6, both often raised in those with endometriosis. Protective effects of the ECS on the gut were observed by increases in endocannabinoids, including 2-AG, resulting in decreased inflammation and improved gut permeability. Given these findings, both the ECS and the gut microbiota may be targets for therapeutic interventions for endometriosis; however, clinical studies are required to determine effectiveness.

Sleep is an essential biological phase of our daily life cycle and is necessary for maintaining homeostasis, alertness, metabolism, cognition, and other key functions across the animal kingdom. Dysfunctional sleep leads to deleterious effects on health, mood, and cognition, including memory deficits and an increased risk of diabetes, stroke, and neurological disorders. Sleep is regulated by several brain neuronal circuits, neuromodulators, and neurotransmitters, where cannabinoids have been increasingly found to play a part in its modulation. Cannabinoids, a group of lipid metabolites, are regulatory molecules that bind mainly to cannabinoid receptors (CB 1 and CB 2 ). Much evidence supports the role of cannabinoid receptors in the modulation of sleep, where their alteration exhibits sleep-promoting effects, including an increase in non-rapid-eye movement sleep and a reduction in sleep latency. However, the pharmacological alteration of CB 1 receptors is associated with adverse psychotropic effects, which are not exhibited in CB 2 receptor alteration. Hence, selective alteration of CB 2 receptors is also of clinical importance, where it could potentially be used in treating sleep disorders. Thus, it is crucial to understand the neurobiological basis of cannabinoids in sleep physiology. In this review article, the alteration of the endocannabinoid system by various cannabinoids and their respective effects on the sleep-wake cycle are discussed based on recent findings. The mechanisms of the cannabinoid receptors on sleep and wakefulness are also explored for their clinical implications and potential therapeutic use on sleep disorders., Competing Interests: Declaration of Competing Interest The authors declare that there are no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 The Authors. Published by Elsevier Masson SAS.. All rights reserved.)

Partial agonists of peripheral cannabinoid receptors (CBRs) have potential therapeutic applications in several medical conditions. However, (-)-trans-Δ 9 -tetrahydrocannabinol (THC), the principal active component of marijuana, which is a partial agonist of CB1 and CB2 penetrates the central nervous system (CNS) and produces adverse effects. Peripherally restricted partial agonists of CBRs, particularly of CB1, can be used to treat illnesses safely and effectively with a better therapeutic index. Here, we report on our efforts to synthesize pyrazole partial CBR agonists with peripheral selectivity, resulting in lead compound 40. This compound is a potent partial agonist of CB1 with ∼ 5-fold higher plasma biodistribution over brain and represents an early lead for optimization., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Introduction: The cannabinoid receptor 2 (CB2) is mainly involved in the immune system. However, although CB2 has been reported to play an anti-tumor function in breast cancer (BC), its specific mechanism in BC remains unclear., Methods: We examined the expression and prognostic significance of CB2 in BC tissues by qPCR, second-generation sequencing, western blot, and immunohistochemistry. We assessed the impacts of overexpression and a specific agonist of CB2 on the growth, proliferation, apoptosis, and drug resistance of BC cells in vitro and in vivo using CCK-8, flow cytometry, TUNEL staining, immunofluorescence, tumor xenografts, western blot, and colony formation assays., Results: CB2 expression was significantly lower in BC compared with paracancerous tissues. It was also highly expressed in benign tumors and ductal carcinoma in situ, and its expression was correlated with prognosis in BC patients. CB2 overexpression and treatment of BC cells with a CB2 agonist inhibited proliferation and promoted apoptosis, and these actions were achieved by suppressing the PI3K/Akt/mTOR signaling pathway. Moreover, CB2 expression was increased in MDA-MB-231 cell treated with cisplatin, doxorubicin, and docetaxel, and sensitivity to these anti-tumor drugs was increased in BC cells overexpressing CB2., Conclusions: These findings reveal that CB2 mediates BC via the PI3K/Akt/mTOR signaling pathway. CB2 could be a novel target for the diagnosis and treatment of BC., (© 2023 The Authors. Cancer Medicine published by John Wiley & Sons Ltd.)

Background: The endocannabinoid system (ECS) and associated lipid transmitter-based signaling systems play an important role in modulating brain neuroinflammation. ECS is affected in neurodegenerative disorders, such as Alzheimer's disease (AD). Here we have evaluated the non-psychotropic endocannabinoid receptor type 2 (CB2) and lysophosphatidylinositol G-protein-coupled receptor 55 (GPR55) localization and expression during Aβ-pathology progression., Methods: Hippocampal gene expression of CB2 and GPR55 was explored by qPCR analysis, and brain distribution was evaluated by immunofluorescence in the wild type (WT) and APP knock-in App NL-G-F AD mouse model. Furthermore, the effects of Aβ42 on CB2 and GPR55 expression were assessed in primary cell cultures., Results: CB2 and GPR55 mRNA levels were significantly upregulated in App NL-G-F mice at 6 and 12 months of age, compared to WT. CB2 was highly expressed in the microglia and astrocytes surrounding the Aβ plaques. Differently, GPR55 staining was mainly detected in neurons and microglia but not in astrocytes. In vitro, Aβ42 treatment enhanced CB2 receptor expression mainly in astrocytes and microglia cells, whereas GPR55 expression was enhanced primarily in neurons., Conclusions: These data show that Aβ pathology progression, particularly Aβ42, plays a crucial role in increasing the expression of CB2 and GPR55 receptors, supporting CB2 and GPR55 implications in AD., Competing Interests: The authors declare no conflict of interest.

Machaeriols and machaeridiols are unique hexahydrodibenzopyran-type aralkyl phytocannabinoids isolated from Machaerium Pers. Earlier studies of machaeriol A ( 1 ) and B ( 2 ) did not show any affinity for cannabinoid receptor 1 (CB1 or CNR1), although they are structural analogs of psychoactive hexahydrocannabinol. This study comprehensively reports on the affinities of isolated Machaerium Pers. compounds, namely machaeriol A-D ( 1 - 4 ) and machaeridiol A-C ( 5 - 7 ), against cannabinoid (CB1 and CB2) and opioid ( κ , δ and µ ) receptors. Among the isolated compounds, machaeriol D ( 4 ) and machaeridiol A-C ( 5 - 7 ) showed some selective binding affinity for the CB2 receptor, using a radioligand binding assay, with K i values of >1.3, >1.77, >2.18 and >1.1 μM, respectively. On the other hand, none of the compounds showed any binding to the CB1 receptor. Due to recent reports on the anticancer potential of the endocannabinoid system, compounds 1 - 7 were tested against a battery of luciferase reporter gene vectors that assess the activity of many cancer-related signaling pathways, including Stat3, Smad2/3, AP-1, NF-κB, E2F, Myc, Ets, Notch, FoxO, Wnt, Hedgehog and pTK in HeLa and T98G glioblastoma cells. Complete dose-response curves have been determined for each compound in both of these cell lines, which revealed that machaeridiol 6 displayed activities (IC 50 in µM in HeLa and T98G cells) towards Stat3 (4.7, 1.4), Smad2/3 (1.2, 3.0), AP-1 (5.9, 4.2), NF-κB (0.5, 4.0), E2F (5.7, 0.7), Myc (5.3, 2.0), ETS (inactive, 5.9), Notch (5.3, 4.6), Wnt (4.2, inactive) and Hedgehog (inactive, 5.0). Furthermore, a combination study between machaeriol C ( 3 ) and machaeridiol B ( 6 ) displayed additive effects for E2F, ETS, Wnt and Hedgehog pathways, where these compounds individually were either minimally active or inactive. None of the compounds inhibited luciferase expression driven by the minimal thymidine kinase promoter (pTK), indicating the lack of general cytotoxicity for luciferase enzyme inhibition at the 50 µM concentration in both of these cell lines. The significance of the inhibition of these signaling pathways via machaeridiol 5 - 7 and their cross-talk potential has been discussed.

Objective: The aim of the present study was to assess if the endocannabinoid system is involved differently in patients with recurrent and non-recurrent periodontal disease and if in sites that have a predisposition for reactivation, levels of anandamide (AEA) change after periodontal therapy., Background: Periodontal disease (PD) may be due to a dysregulation of the endocannabinoid system., Methods: Periodontal patients were recruited, treated for PD and monitored. Gingival samples from these patients with recurrent (n = 10) and non-recurrent (n = 10) periodontal disease were harvested before and after treatment and compared to those of periodontally healthy (n = 10) subjects. Levels of CB1 and CB2, AEA and CBs receptor activation were assessed in healthy and inflamed samples using immunohistochemistry, chromatography and autoradiography. In healed sites, AEA levels were also assessed., Results: The number of CBs in inflamed sites of recurrent patients was significantly higher than in those with non-recurrent disease and also higher than those in healthy subjects. Inflamed sites of recurrent patients had significantly lower CBs receptor activation than those of healthy subjects. Levels of AEA in inflamed sites of non-recurrent patients were significantly higher than those found both in inflamed recurrent sites and in healthy sites. Otherwise, the amount of AEA in healthy subjects and recurrent inflamed sites was similar. After periodontal therapy, levels of AEA were significantly lower in both periodontal groups. In recurrent sites, they resulted significantly lower than in non-recurrent and even in healthy subjects., Conclusions: The endocannabinoid system seems involved differently in subjects with recurrent and non-recurrent periodontal disease., (© 2023 The Authors. Journal of Periodontal Research published by John Wiley & Sons Ltd.)

Cannabinoid Receptor 2 (CB2) is a promising target for treating inflammatory diseases. We designed derivatives of 3-carbamoyl-2-pyridone and 1,8-naphthyridin-2(1H)-one-3-carboxamide CB2-selective agonists with reduced lipophilicity. The new compounds were measured for their affinity (radioligand binding) and ability to elicit cyclic adenosine monophosphate (cAMP) signalling and β-arrestin-2 translocation with temporal resolution (BRET-based biosensors). For the 3-carbamoyl-2-pyridone derivatives, we found that modifying the previously reported compound UOSS77 (also known as S-777469) by appending a PEG2-alcohol via a 3-carbomylcyclohexyl carboxamide (UOSS75) lowered lipophilicity, and preserved binding affinity and signalling profile. The 1,8-naphthyridin-2(1H)-one-3-carboxamide UOMM18, containing a cis configuration at the 3-carboxamide cyclohexyl and with an alcohol on the 4-position of the cyclohexyl, had lower lipophilicity but similar CB2 affinity and biological activity to previously reported compounds of this class. Relative to CP55,940, the new compounds acted as partial agonists and did not exhibit signalling bias. Interestingly, while all compounds shared similar temporal trajectories for maximal efficacy, differing temporal trajectories for potency were observed. Consequently, when applied at sub-maximal concentrations, CP55,940 tended to elicit sustained (cAMP) or increasing (arrestin) responses, whereas responses to the new compounds tended to be transient (cAMP) or sustained (arrestin). In future studies, the compounds characterised here may be useful in elucidating the consequences of differential temporal signalling profiles on CB2-mediated physiological responses.

Mast cells (MCs) are the main participants in the control of immune reactions associated with inflammation, allergies, defense against pathogens, and tumor growth. Bioactive lipids are lipophilic compounds able to modulate MC activation. Here, we explored some of the effects of the bioactive lipid lysophosphatidylinositol (LPI) on MCs. Utilizing murine bone marrow-derived mast cells (BMMCs), we found that LPI did not cause degranulation, but slightly increased FcεRI-dependent β-hexosaminidase release. However, LPI induced strong chemotaxis together with changes in LIM kinase (LIMK) and cofilin phosphorylation. LPI also promoted modifications to actin cytoskeleton dynamics that were detected by an increase in cell size and interruptions in the continuity of the cortical actin ring. The chemotaxis and cortical actin ring changes were dependent on GPR55 receptor activation, since the specific agonist O1602 mimicked the effects of LPI and the selective antagonist ML193 prevented them. The LPI and O1602-dependent stimulation of BMMC also led to VEGF, TNF, IL-1α, and IL-1β mRNA accumulation, but, in contrast with chemotaxis-related processes, the effects on cytokine transcription were dependent on GPR55 and cannabinoid (CB) 2 receptors, since they were sensitive to ML193 and to the specific CB2 receptor antagonist AM630. Remarkably, GPR55-dependent BMMC chemotaxis was observed towards conditioned media from distinct mouse and human cancer cells. Our data suggest that LPI induces the chemotaxis of MCs and leads to cytokine production in MC in vitro with the differential participation of GPR55 and CB2 receptors. These effects could play a significant role in the recruitment of MCs to tumors and the production of MC-derived pro-angiogenic factors in the tumor microenvironment.

GPR55 is a non-canonical cannabinoid receptor, important for cancer proliferation. Depending on the ligand, it induces either cell proliferation or death. The objective of the study was to establish the mechanisms of this multidirectional signaling. Using the CRISPR-Cas9 system, the GPR55, CB1, CB2, and GPR18 receptor knockouts of the MDA-MB-231 line were obtained. After the CB2 receptor knockout, the pro-apoptotic activity of the pro-apoptotic ligand docosahexaenoyl dopamine (DHA-DA) slightly increased, while the pro-proliferative activity of the most active synthetic ligand of the GPR55 receptor (ML-184) completely disappeared. On the original cell line, the stimulatory effect of ML-184 was removed by the CB2 receptor blocker and by GPR55 receptor knockout. Thus, it can be confidently assumed that when proliferation is stimulated with the participation of the GPR55 receptor, a signal is transmitted from the CB2 receptor to the GPR55 receptor due to the formation of a heterodimer. GPR18 was additionally involved in the implementation of the pro-apoptotic effect of DHA-DA, while the CB1 receptor is not involved. In the implementation of the pro-apoptotic action of DHA-DA, the elimination of Gα 13 led to a decrease in cytotoxicity. The obtained data provide novel details to the mechanism of the pro-proliferative action of GPR55.

The endocannabinoid system (ECS) is involved in various processes, including brain plasticity, learning and memory, neuronal development, nociception, inflammation, appetite regulation, digestion, metabolism, energy balance, motility, and regulation of stress and emotions. Physical exercise (PE) is considered a valuable non-pharmacological therapy that is an immediately available and cost-effective method with a lot of health benefits, one of them being the activation of the endogenous cannabinoids. Endocannabinoids (eCBs) are generated as a response to high-intensity activities and can act as short-term circuit breakers, generating antinociceptive responses for a short and variable period of time. A runner's high is an ephemeral feeling some sport practitioners experience during endurance activities, such as running. The release of eCBs during sustained physical exercise appears to be involved in triggering this phenomenon. The last decades have been characterized by an increased interest in this emotional state induced by exercise, as it is believed to alleviate pain, induce mild sedation, increase euphoric levels, and have anxiolytic effects. This review provides information about the current state of knowledge about endocannabinoids and physical effort and also an overview of the studies published in the specialized literature about this subject.

Cannabinoid (CB) receptors (CB 1 and CB 2 ) are expressed on cancer cells and their expression influences carcinogenesis in various tumor entities. Cells of the tumor microenvironment (TME) also express CB receptors, however, their role in tumor development is still unclear. We, therefore, investigated the role of TME-derived CB 1 and CB 2 receptors in a model of non-small cell lung cancer (NSCLC). Leukocytes in the TME of mouse and human NSCLC express CB receptors, with CB 2 showing higher expression than CB 1 . In the tumor model, using CB 1 - (CB 1 -/- ) and CB 2 -knockout (CB 2 -/- ) mice, only deficiency of CB 2 , but not of CB 1 , resulted in reduction of tumor burden vs. wild type (WT) littermates. This was accompanied by increased accumulation and tumoricidal activity of CD8 + T and natural killer cells, as well as increased expression of programmed death-1 (PD-1) and its ligand on lymphoid and myeloid cells, respectively. CB 2 -/- mice responded significantly better to anti-PD-1 therapy than WT mice. The treatment further increased infiltration of cytotoxic lymphocytes into the TME of CB 2 -/- mice. Our findings demonstrate that TME-derived CB 2 dictates the immune cell recruitment into tumors and the responsiveness to anti-PD-1 therapy in a model of NSCLC. CB 2 could serve as an adjuvant target for immunotherapy., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Sarsembayeva, Kienzl, Gruden, Ristic, Maitz, Valadez-Cosmes, Santiso, Hasenoehrl, Brcic, Lindenmann, Kargl and Schicho.)

The discovery of cannabinoid receptors as the primary molecular targets of psychotropic cannabinoid Δ 9 -tetrahydrocannabinol (Δ 9 -THC) in late 1980s paved the way for investigations on the effects of cannabis-based therapeutics in brain pathology. Ever since, a wealth of results obtained from studies on human tissue samples and animal models have highlighted a promising therapeutic potential of cannabinoids and endocannabinoids in a variety of neurological disorders. However, clinical success has been limited and major questions concerning endocannabinoid signaling need to be satisfactorily addressed, particularly with regard to their role as modulators of glial cells in neurodegenerative diseases. Indeed, recent studies have brought into the limelight diverse, often unexpected functions of astrocytes, oligodendrocytes, and microglia in brain injury and disease, thus providing scientific basis for targeting glial cells to treat brain disorders. This Review summarizes the current knowledge on the molecular and cellular hallmarks of endocannabinoid signaling in glial cells and its clinical relevance in neurodegenerative and chronic inflammatory disorders., (© 2022 The Authors. GLIA published by Wiley Periodicals LLC.)

Cannabinoid receptors, as part of the family of the G protein-coupled receptors (GPCRs), are involved in various physiological functions. Its subtype cannabinoid receptor subtype 2 (CB2), mainly distributed in the periphery, is a crucial therapeutic target for anti-epileptic, anti-inflammation, anti-fibrosis, and bone metabolism regulation, and it regulates these physiological functions without psychiatric side effects. Recently machine learning methods for predicting biophysics properties have attracted much attention. Successful application of machine learning usually highly depends on the appropriate representation of the compounds. In this study, we comprehensively evaluate the performance of the descriptor-based models (including XGBoost, Random Forest, and KNN) and two graph-based models (D-MPNN, MolMap) for the prediction of the CB2 regulators, and found that XGBoost offers outstanding performance for both regression tasks and classification tasks. 13 different molecular fingerprints and 12 descriptors, as well as their combination were further screened; AvalonFP + AtomPairFP + RDkitFP + MorganFP and AtomPairFP + MorganFP + AvalonFP were the optimum combinations for regression task (R 2 increase to 0.667) and classification task (AUC-ROC increase to 0.933), respectively. Specifically, the best XGBoost regression model with optimum features achieves better performance than Mizera's QSAR model on the same dataset developed by Mizera (R 2 0.664 versus 0.62). It also achieves optimal performance with an AUC-ROC of 0.917 on the external validation set. By comparison, MolMap and D-MPNN only provide 0.912 and 0.898. The Shapley additive explanation method was used to interpret the models, and features importance were shown for both regression and classification task. The XGBoost model equipped with essential molecular fingerprints combination in this paper may provide valuable clues to designing novel CB2 ligands and developing models for other properties prediction., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Painful peripheral neuropathy is a common neurological complication associated with human immunodeficiency virus (HIV) infection and anti-retroviral therapy. We characterized the impact of two CB2 cannabinoid agonists (AM1710 and LY2828360 - ligands differing in signaling bias and CNS penetration) on neuropathic nociception induced by the antiretroviral agent Zalcitabine (2',3'-dideoxycytidine; ddC). We also used a conditional knockout approach to identify cell types mediating CB2 agonist-induced antinociceptive efficacy and sparing of morphine tolerance. AM1710 and LY2828360 alleviated ddC-induced neuropathic nociception in mice of both sexes. These benefits were absent in global CB2 knockout mice, which exhibited robust morphine antinociception. Like morphine, AM1710 blunted ddC-induced increases in proinflammatory cytokine (IL-1β, TNF-α) and chemokine (CCL2) mRNA expression levels. We generated advillin Cre/+ ;CB2 f/f conditional knockout mice to ascertain the role of CB2 localized to primary sensory neurons in CB2-mediated therapeutic effects. Antinociceptive efficacy of both AM1710 and LY2828360, but not reference analgesics, were absent in advillin Cre/+ ;CB2 f/f mice, which exhibited robust ddC-induced neuropathy. In ddC-treated CB2 f/f mice, LY2828360 suppressed development of morphine tolerance and reversed established morphine tolerance, albeit with greater efficacy in male compared to female mice. LY2828360 failed to block or reverse morphine tolerance in advillin Cre/+ ;CB2 f/f mice. The present studies indicate that CB2 activation may alleviate HIV-associated antiretroviral neuropathy and identify a previously unreported mechanism through which CB2 activation produces antinociceptive efficacy. Our results also provide the first evidence that a CB2 agonist can reverse established morphine tolerance and demonstrate that CB2 localized to peripheral sensory neurons mediates the opioid tolerance sparing efficacy of CB2 agonists., Competing Interests: Conflict of interest statement The authors have no conflicts of interest, financial or otherwise, to declare., (Copyright © 2022 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Background: Alcohol use disorder (AUD) commonly occurs in patients with chronic pain, and a major barrier to achieving abstinence and preventing relapse is the emergence of hyperalgesia during alcohol withdrawal. Elucidating novel therapeutic approaches to target hyperalgesia associated with alcohol withdrawal could have important implications for treating AUD. Here, we examined the role of 2-arachidonoylglycerol (2-AG)-mediated endocannabinoid (eCB) signaling in the regulation of hyperalgesia associated with alcohol withdrawal in mice. We tested the hypothesis that pharmacological augmentation of 2-AG signaling could reduce hyperalgesia during withdrawal., Methods: Male and female C57BL/6J mice were tested during withdrawal from a continuous access two-bottle choice (2BC) paradigm to investigate how eCB signaling modulates mechanical and thermal sensitivity during withdrawal. Mice were pretreated with the monoacylglycerol lipase (MAGL) inhibitor JZL184 to elevate levels of 2-AG. Rimonabant or AM630 were given to block CB 1 and CB 2 receptor activity, respectively. DO34 was given to reduce 2-AG by inhibiting the 2-AG synthetic enzyme diacylglycerol lipase (DAGL)., Results: After 72 h of withdrawal, male and female mice exhibited increased mechanical, but not thermal, hypersensitivity, which normalized by 7 days. This effect was reversed by pretreatment with JZL184. The effects of JZL184 were prevented by coadministration of either the CB 1 or the CB 2 antagonist. DO34, Rimonabant, and AM630 exacerbated mechanical hypersensitivity during alcohol withdrawal, causing an earlier onset and persistent hypersensitivity even 1 week into withdrawal., Conclusions: Our findings demonstrate the critical role of 2-AG signaling in the bidirectional regulation of mechanical sensitivity during alcohol withdrawal, with enhancement of 2-AG levels reducing sensitivity, and inhibition of 2-AG signaling exacerbating sensitivity. These data suggest that 2-AG augmentation represents a novel approach to the treatment of alcohol withdrawal-associated hyperalgesia and AUD in patients with comorbid pain disorders., (© 2022 The Authors. Alcoholism: Clinical & Experimental Research published by Wiley Periodicals LLC on behalf of Research Society on Alcoholism.)

Background: As effective immune modulators, Endocannabinoids may suppress the inflammatory responses in periodontitis. This study assessed the expression of cannabinoid receptors in gingiva and the impact on periodontitis., Methods: A cross-sectional study on 20 patients with more than stage II and Grade A periodontitis and a control group consisting of 19 healthy individuals was performed. The gingival biopsies were assessed for the expression of CB1 and CB2 using the quantitative reverse transcription polymerase chain reaction, TaqMan method., Results: The study sample consisted of 39 subjects, 31 females (79.5%) and 8 males (20.5%), including 20 periodontitis subjects (80% female and 20% male), and control groups (78.9% female and 21.1% male). The mean ages of cases and controls were 33.3 ± 4.7 and 35.7 ± 5.1 years, respectively. The gene expression of CB2 in periodontitis was 27.62 ± 7.96 and in healthy subjects was 78.15 ± 23.07. The CB2 was significantly lower than the control group (p = .008). In comparison, the gene expression index of CB1 in the periodontal group (9.42 ± 3.03) was higher than the control group (6.62 ± 1.13) but did not meet a significant value (p = .671)., Conclusion: The lower expression of CB2 receptors in the periodontitis group may be due to the reduced protective effect of anti-inflammatory agents. These elements include cannabinoids and the imbalance leading to the predominance of pro-inflammatory effects. Therefore, the local effects of cannabinoids as an immunomodulator could be useful for oral inflammatory diseases such as periodontitis., (© 2022 The Authors. Clinical and Experimental Dental Research published by John Wiley & Sons Ltd.)

Cannabinoid signaling, mainly via CB1 and CB2 receptors, plays an essential role in oligodendrocyte health and functions. However, the specific molecular signals associated with the activation or blockade of CB1 and CB2 receptors in this glial cell have yet to be elucidated. Mass spectrometry-based shotgun proteomics and in silico biology tools were used to determine which signaling pathways and molecular mechanisms are triggered in a human oligodendrocytic cell line (MO3.13) by several pharmacological stimuli: the phytocannabinoid cannabidiol (CBD); CB1 and CB2 agonists ACEA, HU308, and WIN55, 212-2; CB1 and CB2 antagonists AM251 and AM630; and endocannabinoids anandamide (AEA) and 2-arachidonoylglycerol (2-AG). The modulation of cannabinoid signaling in MO3.13 was found to affect pathways linked to cell proliferation, migration, and differentiation of oligodendrocyte progenitor cells. Additionally, we found that carbohydrate and lipid metabolism, as well as mitochondrial function, were modulated by these compounds. Comparing the proteome changes and upstream regulators among treatments, the highest overlap was between the CB1 and CB2 antagonists, followed by overlaps between AEA and 2-AG. Our study opens new windows of opportunities, suggesting that cannabinoid signaling in oligodendrocytes might be relevant in the context of demyelinating and neurodegenerative diseases. Proteomics data are available at ProteomeXchange (PXD031923)., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany.)

Selective modulation of peripheral cannabinoid receptors (CBRs) has potential therapeutic applications in medical conditions, including obesity, diabetes, liver diseases, GI disorders and pain. While there have been considerable efforts to produce selective antagonists or full agonists of CBRs, there has been limited reports on the development of partial agonists. Partial agonists targeting peripheral CBRs may have desirable pharmacological profiles while not producing centrally mediated dissociative effects. Bayer reported that BAY 59-3074 is a CNS penetrant partial agonist of both CB1 and CB2 receptors with efficacy in rat models of neuropathic and inflammatory pain. In this report, we demonstrate our efforts to synthesize analogs that would favor peripheral selectivity, while maintaining partial agonism of CB1. Our efforts led to the identification of a novel compound, which is a partial agonist of the human CB1 (hCB1) receptor with vastly diminished brain exposure compared to BAY 59-3074., Competing Interests: The authors do not have known conflict of interest.

Cannabinoid Receptor 2 (CB2) is a G protein-coupled receptor (GPCR) with considerable, though as yet unrealised, therapeutic potential. Promising preclinical data supports the applicability of CB2 activation in autoimmune and inflammatory diseases, pain, neurodegeneration, and osteoporosis. A diverse pharmacopoeia of cannabinoid ligands is available, which has led to considerable advancements in the understanding of CB2 function and extensive preclinical evaluation. However, until recently, most CB2 ligands were highly lipophilic and as such not optimal for clinical application due to unfavourable physicochemical properties. A number of strategies have been applied to develop CB2 ligands to achieve closer to 'drug-like' properties and a few such compounds have now undergone clinical trial. We review the current state of CB2 ligand development and progress in optimising physicochemical properties, understanding advanced molecular pharmacology such as functional selectivity, and clinical evaluation of CB2-targeting compounds., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Background: The reduction of bone mineral density and osteoporosis have high impacts on the health of patients with inflammatory bowel diseases (IBD). We have previously shown that a dysregulated iron metabolism occurs in IBD and leads to a decrease in circulating iron concentration and excessive intracellular sequestration of iron. Studies suggest that iron overload significantly affects the bone, accelerating osteoclast (OC) differentiation and activation, promoting bone resorption. Moreover, we demonstrated that iron overload causes OC overactivity. The cannabinoid receptor type 2 (CB2) and the transient receptor potential vanilloid type-1 (TRPV1) are potential therapeutic targets for bone diseases. The aim of this study was to evaluate the roles of CB2 and TRPV1 receptors and of iron in the development of osteoporosis in pediatric IBD., Methods: We differentiated OCs from peripheral blood mononuclear cells of patients with IBD and healthy donors and evaluated CB2 and TRPV1 receptor expression; OC activity, and iron metabolism by Western blot, TRAP assays, bone resorption assays, and iron assays. Moreover, we analyzed the effects of the pharmacological modulation of CB2 and TRPV1 receptors on OC activity and on the iron metabolism., Results: We confirmed the well-known roles of CB2 and TRPV1 receptors in bone metabolism and suggested that their stimulation can reduce the OC overactivity induced by iron, providing new insights into the pathogenesis of pediatric IBD-related bone resorption., Conclusions: Stimulation of CB2 and TRPV1 could reduce IBD-related osteoporosis due to their direct effects on OC activity and to modulating the iron metabolism., (© 2022 Crohn’s & Colitis Foundation. Published by Oxford University Press on behalf of Crohn’s & Colitis Foundation.)

NMDA receptor blockade in rodents is commonly used to induce schizophrenia-like behavioral abnormalities, including cognitive deficits and social dysfunction. Aberrant glutamate and GABA transmission, particularly in adolescence, is implicated in these behavioral abnormalities. The endocannabinoid system modulates glutamate and GABA transmission, but the impact of endocannabinoid modulation on cognitive and social dysfunction is unclear. Here, we asked whether late-adolescence administration of the anandamide hydrolysis inhibitor URB597 can reverse behavioral deficits induced by early-adolescence administration of the NMDA receptor blocker MK-801. In parallel, we assessed the impact of MK-801 and URB597 on mRNA expression of glutamate and GABA markers. We found that URB597 prevented MK-801-induced novel object recognition deficits and social interaction abnormalities in adult rats, and reversed glutamate and GABA aberrations in the prelimbic PFC. URB597-mediated reversal of MK-801-induced social interaction deficits was mediated by the CB1 receptor, whereas the reversal of cognitive deficits was mediated by the CB2 receptor. This was paralleled by the reversal of CB1 and CB2 receptor expression abnormalities in the basolateral amygdala and prelimbic PFC, respectively. Together, our findings show that interfering with NMDA receptor function in early adolescence has a lasting impact on phenotypes resembling the negative symptoms and cognitive deficits of schizophrenia and on glutamate and GABA marker expression in the PFC. Prevention of behavioral and molecular abnormalities by late-adolescence URB597 via CB1 and CB2 receptors suggests that endocannabinoid stimulation may have therapeutic potential in addressing treatment-resistant symptoms., (© The Author(s) 2022. Published by Oxford University Press on behalf of the Maryland Psychiatric Research Center. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

Background: Neuropathic pain is a condition caused by a lesion or disease of the somatosensory nervous system. It may present as debilitating pain with a sensation of burning and electric-like symptoms and is often difficult to manage effectively. Although pharmacological medications are the first line of treatment, multidisciplinary teams are sometimes required to provide appropriate treatment to improve quality of life and overall wellbeing., Aim: The aim of this study is to present a case of post herpetic neuralgia relieved successfully by the compound palmitoylethanolamide (PEA) - a natural alternative to pharmacological pain relief., Methods: We present the case of a 67 year-old male with ongoing post-herpetic neuralgia, over a 3-year period, as a result of complications from shingles (herpes zoster). Previous studies on the relationship between PEA and neuropathy were reviewed, with an attempt to discuss the possible underlying mechanism of PEA on neuropathic pain., Results: PEA demonstrated effective pain relief within 48 hours at an administered daily dose of 900 mg (10 mg/kg)., Conclusions: PEA may offer a valid nutraceutical treatment for practitioners.

Childhood absence epilepsy (CAE) is characterized by absence seizures, which are episodes of lack of consciousness accompanied by electrographic spike-wave discharges. About 60% of children and adolescents with absence seizures are affected by major neuropsychological comorbidities, including anxiety. Endocannabinoids and monoamines are likely involved in the pathophysiology of these CAE psychiatric comorbidities. Here, we show that the synthetic cannabinoid receptor type 1/2 (CB1/2R) agonist WIN 55,212-2 (2 mg/kg) has a strain-dependent effect on anxiety-like and motor behavior when assess in the hole board test and cerebral monoaminergic levels in Genetic Absence Epilepsy Rats from Strasbourg (GAERS) and their non-epileptic control (NEC) rat strain. Using quantitative and Temporal pattern (T-pattern) analyses, we found that WIN 55,212-2 did not affect the emotional status of GAERS, but it was anxiolytic in NEC. Conversely, WIN 55,212-2 had a sedative effect in GAERS but was ineffective in NEC. Moreover, vehicle-treated GAERS more motivated to explore by implementing more complex and articulated strategies. These behavioral changes correlate with the reduction of 5-HT in the hippocampus and substantia nigra (SN) and noradrenaline (NA) in the entopeduncular nucleus (EPN) in vehicle-treated GAERS compared to NEC rats, which could contribute to their low anxiety status and hypermotility, respectively. On the other hand, the increased level of NA in the EPN and 5-HT in the SN is consistent with an activation of the basal ganglia output-mediated motor suppression observed in WIN 55,212-2-treated GAERS rats. These data support the view of a strain-dependent alteration of the endocannabinoid system in absence epilepsy by adding evidence of a lower emotional responsiveness and a basal ganglia hypersensitivity to cannabinoids in GAERS compared to NEC rats., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 De Deurwaerdère, Casarrubea, Cassar, Radic, Puginier, Chagraoui, Crescimanno, Crunelli and Di Giovanni.)

The endocannabinoid system consists mainly of 2-arachidonoylglycerol and anandamide, as well as cannabinoid receptor type 1 and type 2 (CB2). Based on previous studies, we hypothesized that a circulating peptide previously identified as osteogenic growth peptide (OGP) maintains a bone-protective CB2 tone. We tested OGP activity in mouse models and cells, and in human osteoblasts. We show that the OGP effects on osteoblast proliferation, osteoclastogenesis, and macrophage inflammation in vitro, as well as rescue of ovariectomy-induced bone loss and prevention of ear edema in vivo are all abrogated by genetic or pharmacological ablation of CB2. We also demonstrate that OGP binds at CB2 and may act as both an agonist and positive allosteric modulator in the presence of other lipophilic agonists. In premenopausal women, OGP circulating levels significantly decline with age. In adult mice, exogenous administration of OGP completely prevented age-related bone loss. Our findings suggest that OGP attenuates age-related bone loss by maintaining a skeletal CB2 tone. Importantly, they also indicate the occurrence of an endogenous peptide that signals via CB2 receptor in health and disease., Competing Interests: BR, MA, MC, MC, AS, JT, MN, NR, ZV, AS, RP, AZ, NK, IB, YG No competing interests declared, (© 2022, Raphael-Mizrahi et al.)

The endocannabinoid system is involved in the nociceptive and anti-inflammatory pathways, and a lowered expression of CB2 receptors has been associated with inflammatory conditions, such as osteoarthritis (OA). This suggests that CB2 modulators could be novel therapeutic tools to treat OA. In the present study, the involvement of Harpagophytum procumbens root extract, a common ingredient of nutraceuticals used to treat joint disorders, in CB2 modulation has been evaluated. Moreover, to clarify the effects of the pure single components, the bioactive constituent, harpagoside, and the main volatile compounds were studied alone or in a reconstituted mixture. Human fibroblast-like synoviocytes, extracted by joints of patients, who underwent a total knee replacement, were treated with an H. procumbens root extract dissolved in DMSO (HPE DMSO ). The effectiveness of HPE DMSO to affect CB2 pathways was studied by analyzing the modulation of cAMP, the activation of PKA and ERK MAP kinase, and the modulation of MMP-13 production. HPE DMSO was able to inhibit the cAMP production and MAP kinase activation and to down-regulate the MMP-13 production. Pure compounds were less effective than the whole phytocomplex, thus suggesting the involvement of synergistic interactions. Present findings encourage further mechanistic studies and support the scientific basis of the use of H. procumbens in joint disorders.

Several studies have shown that the G-protein coupled cannabinoid receptor CB2 and its interaction partner p62 are molecularly involved in bone remodeling processes. Pharmacological activation of the CB2 receptor enhanced bone volume in postmenopausal osteoporosis and arthritis models in rodents, whereas knockout or mutation of the p62 protein in aged mice led to Paget's disease of bone-like conditions. Studies of pharmacological CB2 agonist effects on bone metabolism in p62 KO mice have not been performed to date. Here, we assessed the effect of the CB2-specific agonist JWH133 after a short-term (5 days in 3-month-old mice) or long-term (4 weeks in 6-month-old mice) treatment on structural, dynamic, and cellular bone morphometry obtained by μCT of the femur and histomorphometry of the vertebral bodies in p62 KO mice and their WT littermates in vivo . A genotype-independent stimulatory effect of CB2 on bone formation, trabecular number, and trabecular thickness after short-term treatment and on tissue mineral density after long-term treatment was detected, indicating a weak osteoanabolic function of this CB2 agonist. Moreover, after short-term systemic CB2 receptor activation, we found significant differences at the cellular level in the number of osteoblasts and osteoclasts only in p62 KO mice, together with a weak increase in trabecular number and a decrease in trabecular separation. Long-term treatment showed an opposite JWH133 effect on osteoclasts in WT versus p62 KO animals and decreased cortical thickness only in treated p62 KO mice. Our results provide new insights into CB2 receptor signaling in vivo and suggest that CB2 agonist activity may be regulated by the presence of its macromolecular binding partner p62., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Keller, Yorgan, Rading, Schinke and Karsak.)

Both metabotropic (CBRs) and ionotropic cannabinoid receptors (ICRs) have implications in a range of neurological disorders. The metabotropic canonical CBRs CB1 and CB2 are highly implicated in these pathological events. However, selective targeting at CB2 versus CB1 offers optimized pharmacology due to the absence of psychoactive outcomes. The ICR transient receptor potential vanilloid type 1 (TRPV1) has also been reported to play a role in CNS disorders. Thus, activation of both targets, CB2 and TRPV1, offers a promising polypharmacological strategy for the treatment of neurological events including analgesia and neuroprotection. This brief research report aims to identify chemotypes with a potential dual CB2/TRPV1 profile. For this purpose, we have rationalized key structural features for activation and performed virtual screening at both targets using curated chemical libraries., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Morales, Muller, Jagerovic and Reggio.)

Zebrafish is considered an unprecedented animal model in drug discovery. A review of the literature presents highlights and elucidates the biological effects of chemical components found in Cannabis sativa. Particular attention is paid to endocannabinoid system (eCB) and its main receptors (CB1 and CB2). The zebrafish model is a promising one for the study of cannabinoids because of the many similarities to the human system. Despite the recent advances on the eCB system, there is still the need to elucidate some of the interactions and, thus, the zebrafish model can be used for that purpose as it respects the 3Rs concept and reduced time and costs. In view of the relevance of cannabinoids in the treatment and prevention of diseases, as well as the importance of the zebrafish animal model in elucidating the biological effects of new drugs, the aim of this study was to bring to light information on the use of the zebrafish animal model in testing C. sativa-based medicines., (© 2022. The Author(s).)

The classical terms agonists and antagonists for G protein coupled receptors (GPCRs) have often become misleading. Even the biased agonism concept does not describe all the possibilities already demonstrated for GPCRs. The cannabinoid CB 2 receptor (CB 2 R) emerged as a promising target for a variety of diseases. Reasons for such huge potential are centered around the way drugs sit in the orthosteric and/or exosites of the receptor. On the one hand, a given drug in a specific CB 2 R conformation leads to a signaling cascade that differs qualitatively and/or quantitatively from that triggered by another drug. On the other hand, a given drug may lead to different signaling outputs in two different tissues (or cell contexts) in which the conformation of the receptor is affected by allosteric effects derived from interactions with other proteins or with membrane lipids. This highlights the pharmacological complexity of this receptor and the need to further unravel the binding mode of CB 2 R ligands in order to fine-tune signaling effects and therapeutic propositions., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Franco, Morales, Navarro, Jagerovic and Reyes-Resina.)

Osteoarthritis (OA) is a chronic joint disease in which cartilage degeneration leads to chronic pain. The endocannabinoid system has attracted attention as an emerging drug target for OA. However, the therapeutic potential of cannabinoids is limited by psychoactive side-effects related to CB1 activation and tolerance development for analgesic effects. β-Caryophyllene (BCP) is a low-efficacy natural agonist of CB2 and a common constituent of human diet with well-established anti-inflammatory properties. The results presented herein show the anti-nociceptive and chondroprotective potential of BCP in an animal model of OA induced by intra-articular injection of monoiodoacetate (MIA). Behavioural assessment included pressure application measurement and kinetic weight bearing tests. Histological assessment of cartilage degeneration was quantified using OARSI scoring. Experiments established the dose-response effects of BCP and pharmacological mechanisms of the antinociceptive action dependent on CB2 and opioid receptors. Chronic BCP treatment was able to hamper cartilage degeneration without producing tolerance for the analgesic effects. The data presented herein show that BCP is able to produce both acute and prolonged antinociceptive and chondroprotective effects. Together with the safety profile and legal status of BCP, these results indicate a novel and promising disease-modifying strategy for treating OA., (Copyright © 2021 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Background: The morbidity and mortality of cancer are significantly impacted by the invasive and metastatic potential of particular subgroups of malignant cells within a tumor. The particular pre-metastatic properties of cancerous cells are thus a critical target for novel therapeutics in the oncology field. Cannabinoid molecules have been investigated in recent years in the context of invasion and metastasis of various malignancies, with varying effects reported in the literature., Recent Findings: There was substantial variability in the findings reported by the literature of the effects of cannabinoid molecules on cancer cell invasion and metastasis. These effects varied depending on which ligand and which of the CB1, CB2, or GPR55 receptors were investigated. These findings suggest a role for the phenomenon of biased signaling in explaining the diversity of effects of cannabinoid molecules on cancer cell invasion., Conclusion: While substantially more investigation is required into the effects of cannabinoid molecules on cancer cell invasion and metastasis, we describe in this review the significant diversity in the responses of cancer cells to cannabinoid molecules in terms of their invasive and metastatic capacities., (© 2021 The Authors. Cancer Reports published by Wiley Periodicals LLC.)

Previous studies showed that cannabinoid 2 (CB2) receptor is involved in skin inflammation, fibrogenesis and re-epithelialization in mice, indicating that this receptor may be implicated in wound healing. Thus, topical use of cannabinoids may have a role in local fibrotic and wound healing diseases such as scars or keloids. We investigate the effect of the CB2 selective receptor agonist (6aR,10aR)-3-(1,1-Dimethylbutyl)-6a,7,10,10a-tetrahydro-6,6,9-trimethyl-6H-dibenzo[b,d]pyran (JWH133) and the CB2 selective receptor antagonist (6-Iodo-2-methyl-1-[2-(4-morpholinyl)ethyl]-1H-indol-3-yl)(4-methoxyphenyl)-methanone (AM630), on primary cultures of human fibroblasts. Primary cultures of adult human fibroblasts were obtained from abdominal human skin samples. Fibroblasts pretreated with JWH133 and/or AM630 were stimulated with TGF-β (10 ng/ml). Fibroblast activation into myofibroblasts was quantified by the expression of alpha-smooth muscle actin (α-SMA) using Immunocytochemistry and Western Blot assays. Collagen content was quantified with the Sirius red staining assay. Upon human fibroblasts stimulation with TGF-β, a significant increase on α-SMA and CB2 receptor expression was observed. In these cells, JWH133 decreased α-SMA expression and collagen content. However, this effect was not observed in resting human fibroblasts. AM630 decreased α-SMA expression and collagen content in both resting and activated fibroblasts. This effect was time- and concentration-dependent with an IC 50 value of 11 μM. The CB2 receptor appears to be involved in fibroblast repair during skin wound healing in humans, as TGF-β increases CB2 receptor expression and JWH133 produces an anti-fibrotic effect in human fibroblasts. AM630 also showed an anti-fibrotic effect hypothesizing that other cannabinoid receptors, such as TRPV, may be involved in this response., (© 2021 Société Française de Pharmacologie et de Thérapeutique.)

Research on endocannabinoid signaling has greatly advanced our understanding of how the excitability of neural circuits is controlled in health and disease. In general, endocannabinoid signaling at excitatory synapses suppresses excitability by inhibiting glutamate release, while that at inhibitory synapses promotes excitability by inhibiting GABA release, although there are some exceptions in genetically epileptic animal models. In the epileptic brain, the physiological distributions of endocannabinoid signaling molecules are disrupted during epileptogenesis, contributing to the occurrence of spontaneous seizures. However, it is still unknown how endocannabinoid signaling changes during seizures and how the redistribution of endocannabinoid signaling molecules proceeds during epileptogenesis. Recent development of cannabinoid sensors has enabled us to investigate endocannabinoid signaling in much greater spatial and temporal details than before. Application of cannabinoid sensors to epilepsy research has elucidated activity-dependent changes in endocannabinoid signaling during seizures. Furthermore, recent endocannabinoid research has paved the way for the clinical use of cannabidiol for the treatment of refractory epilepsy, such as Dravet syndrome, Lennox-Gastaut syndrome and tuberous sclerosis complex. Cannabidiol significantly reduces seizures and is considered to have comparable tolerability to conventional antiepileptic drugs. In this article, we introduce recent advances in research on the roles of endocannabinoid signaling in epileptic seizures and discuss future directions., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Sugaya and Kano.)

The global pandemic caused by the SARS-CoV-2 virus began in early 2020 and is still present. The respiratory symptoms caused by COVID-19 are well established. However, neurological manifestations that may result from direct or indirect neurological damage after SARS-CoV-2 infection have been reported frequently. The main proposed pathophysiological processes leading to neurological damage in COVID-19 are cerebrovascular disease and indirect inflammatory/ autoimmune origin mechanisms. A growing number of studies confirm that neuroprotective measures should be maintained in COVID-19 patients. On the other hand, cannabinoids have been the subject of various studies that propose them as potentially promising drugs in chronic neurodegenerative diseases due to their powerful neuroprotective potential. In this review, we addresses the possible mechanism of action of cannabinoids as a neuroprotective treatment in patients infected by SARS-CoV-2. The endocannabinoid system is found in multiple systems within the body, including the immune system. Its activation can lead to beneficial results, such as a decrease in viral entry, a reduction of viral replication, and a reduction of pro-inflammatory cytokines such as IL-2, IL-4, IL-6, IL-12, TNF-α, or IFN-c through CB2R expression induced during inflammation by SARS-CoV-2 infection in the central nervous system., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)

Cannabis legalization continues to progress in many US states and other countries. Δ 9 -tetrahydrocannabinol (Δ 9 -THC) is the major psychoactive constituent in cannabis underlying both its abuse potential and the majority of therapeutic applications. However, the neural mechanisms underlying cannabis action are not fully understood. In this chapter, we first review recent progress in cannabinoid receptor research, and then examine the acute CNS effects of Δ 9 -THC or other cannabinoids (WIN55212-2) with a focus on their receptor mechanisms. In experimental animals, Δ 9 -THC or WIN55212-2 produces classical pharmacological effects (analgesia, catalepsy, hypothermia, hypolocomotion), biphasic changes in affect (reward vs. aversion, anxiety vs. anxiety relief), and cognitive deficits (spatial learning and memory, short-term memory). Accumulating evidence indicates that activation of CB 1 Rs underlies the majority of Δ 9 -THC or WIN55121-2's pharmacological and behavioral effects. Unexpectedly, glutamatergic CB 1 Rs preferentially underlie cannabis action relative to GABAergic CB 1 Rs. Functional roles for CB 1 Rs expressed on astrocytes and mitochondria have also been uncovered. In addition, Δ 9 -THC or WIN55212-2 is an agonist at CB 2 R, GPR55 and PPARγ receptors and recent studies implicate these receptors in a number of their CNS effects. Other receptors (such as serotonin, opioid, and adenosine receptors) also modulate Δ 9 -THC's actions and their contributions are detailed. This chapter describes the neural mechanisms underlying cannabis action, which may lead to new discoveries in cannabis-based medication development for the treatment of cannabis use disorder and other human diseases., Competing Interests: Conflict of interest The authors have no conflicts of interest to declare., (Copyright © 2022 Elsevier Inc. All rights reserved.)

To address the inconsistent findings from studies that used different models to explore the role of classical cannabinoid type 1 (CB1) and 2 (CB2) receptors in skeletal remodelling, we searched Medline, Web of Science and Embase for relevant studies from inception to June 23, 2020. We identified 38 in vitro, 34 in vivo and 9 human studies. A meta-analysis of in vitro studies showed that exposure to the inverse-agonists AM251 (mean difference [MD]:-26.75, 95% confidence interval [CI]:-45.36,-8.14, p = 0.005), AM630 (standardised[std.] MD:-3.11, CI:-5.26,-0.97, p = 0.004; SR144528, std.MD:-4.88, CI -7.58,-2.18, p = 0.0004) and CBD (std.MD:-1.39, CI -2.64,-0.14, p = 0.03) is associated with reduced osteoclastogenesis, whereas the endocannabinoid 2-AG (std.MD:2.00, CI:0.11-3.89, p = 0.04) and CB2-selective agonist HU308 (MD:19.38, CI:11.75-27.01, p < 0.00001) were stimulatory. HU308 also enhanced osteoblast differentiation (std.MD:2.22, CI:0.95-3.50, p = 0.0006) and activity (std.MD:2.97, CI:1.22-4.71, p = 0.0008). In models of bone loss, CB1/2 deficiency enhanced peak bone volume (std.MD:3.70, CI:1.77-5.63, p = 0.0002) but reduced bone formation (std.MD:-0.54, CI:-0.90,-0.17, p = 0.004) in female mice. In male rats, CB1/2 deficiency (std.MD:2.31, CI:0.30-4.33, p = 0.02) and AM251 or CBD treatments (std.MD:2.19, CI:0.46-3.93, p = 0.01) enhanced bone volume. CB1/2 deficiency (std.MD:9.78, CI:4.96-14.61, p < 0.0001) and AM251 or AM630 treatments (std.MD:28.19, CI:19.13-37.25, p < 0.0001) were associated with osteoprotection. The CB2-selective agonists JWH133 and 4Q3C enhanced bone volume in arthritic rodents (std.MD:14.45, CI:2.08-26.81, p = 0.02). In human, CB2 SNPs (AA:rs2501431, MD:-0.28, CI:-0.55,-0.01, p = 0.04; CC:rs2501432, MD:-0.29, CI:-0.56,-0.02, p = 0.03) were associated with reduced bone mineral density, however the association of Marijuana use remains unclear. Thus, CB1/2 modulation is associated with altered bone metabolism, however findings are confounded by low study number and heterogenicity of models., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Background/aim: The cannabinoid 2 (CB2) receptor is an important regulator of immunoinflammatory responses. Crude drugs commonly used in Japanese traditional Kampo medicine have displayed anti-inflammatory effects; however, few studies have reported that these effects are mediated via CB2 receptor signaling. Therefore, this study aimed to elucidate CB2 receptor-related anti-inflammatory regulation in crude drugs., Materials and Methods: The ethanol extracts of 34 crude drugs listed in the Japanese Pharmacopeia were tested, and the inhibitory effects on lipopolysaccharide (LPS)-induced nitric oxide (NO) production were evaluated in murine macrophage RAW 264 cells., Results: The extracts of Curcumae Longae Rhizoma (dried rhizome of Curcuma longa) and Saussureae Radix (dried root of Saussurea lappa) significantly inhibited NO production and attenuated the LPS-induced decrease in CB2 receptor mRNA expression., Conclusion: Curcumae Longae Rhizoma and Saussureae Radix can modulate the CB2-receptor-related anti-inflammatory regulation in macrophages., (Copyright © 2022 International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.)