New Insights in Cannabinoid Receptor Structure and Signaling

Medical Misinformation and Quality of Public Video Content on Cannabis for Chronic Pain Management: A Cross-Sectional Analysis of the YouTube Platform

Background

As cannabis legalization expands nationally and globally, its use for chronic pain increases, prompting people to seek information on social media platforms like YouTube. This study evaluates the accuracy and quality of information of popular YouTube videos on cannabis for chronic pain.

Methods

Using search terms related to cannabis for pain, the top 66 videos by view count were selected. Each video was classified as useful, misleading, or neither. The quality and reliability of each video were assessed using the modified DISCERN, mDISCERN, score and the Global Quality Scale, GQS. The video characteristics, usefulness classification, mDISCERN scores, and GQS scores were summarized. Continuous and categorical outcomes were compared using t-test and chi-square, respectively.

Results

Of the 66 videos, 22.73% (n=15) were classified as useful, and 77.27% (n=51) were classified as neither. Of useful videos, 40.00% (n=6) were uploaded by physicians, 40.00% (n=6) were uploaded by corporations, and 6.67% (n=1) were uploaded by an independent user. Of videos classified as neither useful nor misleading, news sources uploaded 27.45% (n=14) of these videos (P=0.02). Physicians uploaded 37.50% (n = 18) of videos with a GQS score ≥3 (P=0.04), while independent users uploaded significantly more videos with a mDISCERN score <3 (22.20%, P=0.02). Useful videos had a mean GQS of 4.00 ± 0.65 compared to a mean GQS of 2.76 ± 0.86 for videos deemed neither (P<0.0001).

Conclusion

This study suggests a moderate quality of YouTube content on cannabis use for chronic pain. Given cannabis's growing popularity and potential for misinformation on popular social media platforms, healthcare professionals and organizations should consider uploading educational videos on this topic on YouTube.

Exploring Endocannabinoid System: Unveiling New Roles in Modulating ER Stress

The endoplasmic reticulum (ER) is the organelle mainly involved in maintaining cellular homeostasis and driving correct protein folding. ER-dependent defects or dysfunctions are associated with the genesis/progression of several pathological conditions, including cancer, inflammation, and neurodegenerative disorders, that are directly or indirectly correlated to a wide set of events collectively named under the term "ER stress". Despite the recent increase in interest concerning ER activity, further research studies are needed to highlight all the mechanisms responsible for ER failure. In this field, recent discoveries paved the way for the comprehension of the strong interaction between ER stress development and the endocannabinoid system. The activity of the endocannabinoid system is mediated by the activation of cannabinoid receptors (CB), G protein-coupled receptors that induce a decrease in cAMP levels, with downstream anti-inflammatory effects. CB activation drives, in most cases, the recovery of ER homeostasis through the regulation of ER stress hallmarks PERK, ATF6, and IRE1. In this review, we focus on the CB role in modulating ER stress, with particular attention to the cellular processes leading to UPR activation and oxidative stress response extinguishment, and to the mechanisms underlying natural cannabinoids' modulation of this complex cellular machine.

Divergent input patterns to the central lateral amygdala play a duet in fear memory formation

Somatostatin (SOM)-expressing neurons in the central lateral amygdala (CeL) are responsible for fear memory learning, but the circuit and molecular mechanisms underlying this biology remain elusive. Here, we found that glutamatergic neurons in the lateral parabrachial nucleus (LPB) directly dominated the activity of CeLSOM neurons, and that selectively inhibiting the LPBGlu→CeLSOM pathway suppressed fear memory acquisition. By contrast, inhibiting CeL-projecting glutamatergic neurons in the paraventricular thalamic nucleus (PVT) interfered with consolidation-related processes. Notably, CeLSOM-innervating neurons in the LPB were modulated by presynaptic cannabinoid receptor 1 (CB1R), and knock down of CB1Rs in LPB glutamatergic neurons enhanced excitatory transmission to the CeL and partially rescued the impairment in fear memory induced by CB1R activation in the CeL. Overall, our study reveals the mechanisms by which CeLSOM neurons mediate the formation of fear memories during fear conditioning in mice, which may provide a new direction for the clinical research of fear-related disorders.

Exploring the evolutionary trajectory and functional landscape of cannabinoid receptors: A comprehensive bioinformatic analysis

The bioinformatic analysis of cannabinoid receptors (CBRs) CB1 and CB2 reveals a detailed picture of their structure, evolution, and physiological significance within the endocannabinoid system (ECS). The study highlights the evolutionary conservation of these receptors evidenced by sequence alignments across diverse species including humans, amphibians, and fish. Both CBRs share a structural hallmark of seven transmembrane (TM) helices, characteristic of class A G-protein-coupled receptors (GPCRs), which are critical for their signalling functions. The study reports a similarity of 44.58 % between both CBR sequences, which suggests that while their evolutionary paths and physiological roles may differ, there is considerable conservation in their structures. Pathway databases like KEGG, Reactome, and WikiPathways were employed to determine the involvement of the receptors in various signalling pathways. The pathway analyses integrated within this study offer a detailed view of the CBRs interactions within a complex network of cannabinoid-related signalling pathways. High-resolution crystal structures (PDB ID: 5U09 for CB1 and 5ZTY for CB2) provided accurate structural information, showing the binding pocket volume and surface area of the receptors, essential for ligand interaction. The comparison between these receptors' natural sequences and their engineered pseudo-CBRs (p-CBRs) showed a high degree of sequence identity, confirming the validity of using p-CBRs in receptor-ligand interaction studies. This comprehensive analysis enhances the understanding of the structural and functional dynamics of cannabinoid receptors, highlighting their physiological roles and their potential as therapeutic targets within the ECS.

Effects of Cannabidiol (CBD) on Doxorubicin-Induced Anxiety and Depression-like Behaviors and mRNA Expression of Inflammatory Markers in Rats

Background: Post-treatment side effects of chemotherapy can include cognitive deficits commonly known as Chemo-brain. The treatment of patients with Doxorubicin (DOX), one of the most widely used chemotherapeutic drugs in the treatment of cancer, can induce depression, anxiety, and impaired cognitive function. Cannabidiol (CBD) is a non-psychoactive component of Cannabis sativa that has been identified as a possible therapeutic agent against many neurodegenerative disorders, including traumatic brain injury, spinal cord injury, Tau-protein-induced neurodegeneration, and neuropathic pain. Therefore, this study aimed to assess whether oral CBD administration could reduce DOX-induced anxiety and depression-like behaviors and alter the expression of mRNA associated with neuroinflammation. Methods: Female Long Evans Hooded rats received intraperitoneal injections of DOX (6 mg/kg) or the vehicle (0.9% saline) once a week for four weeks, followed by oral administration of CBD (10 mg/kg) three times a week for the same period. Results: CBD was significantly protective against DOX-induced anxiety and depression-like behaviors, as measured by several behavioral tests. Furthermore, CBD improved DOX-induced alterations in the gene expression of biomarkers of neuroinflammation in the hippocampus and prefrontal cortex. Conclusions: This provides insights into future studies on possible mechanisms by which DOX-induced cognitive dysfunction could be alleviated by CBD.

Evidence for enduring cardiac and multiorgan toxicity after repeated exposure to the synthetic cannabinoid JWH-018 in male rats

The use of synthetic cannabinoid receptor agonists (SCRAs) represents a public health concern. Besides abuse liability and cognitive impairments, SCRAs consumption is associated with serious medical consequences in humans, including cardiotoxicity. The precise mechanisms underlying cardiac or other toxicities induced by SCRAs are not well understood. Here, we used in silico, in vivo, and ex vivo approaches to investigate the toxicological consequences induced by exposure to the SCRA JWH-018. Along with in silico predictive toxicological screening of 36 SCRAs by MC4PC software, adult male Sprague-Dawley rats were repeatedly exposed to JWH-018 (0.25 mg/kg ip) for 14 consecutive days, with body temperature and cardiovascular parameters measured over the course of treatment. At 1 and 7 days after JWH-018 discontinuation, multiorgan tissue pathologies and heart mitochondria bioenergetics were assessed. The in silico findings predicted risk of cardiac adverse effects specifically for JWH-018 and other aminoalkylindole SCRAs (i.e., electrocardiogram abnormality and QT prolongation). The results from rats revealed that repeated, but not single, JWH-018 exposure induced hypothermia and cardiovascular stimulation (e.g., increased blood pressure and heart rate) which persisted throughout treatment. Post-mortem findings demonstrated cardiac lesions (i.e., vacuolization, waving, edema) 1 day after JWH-018 discontinuation, which may contribute to lung, kidney, and liver tissue degeneration observed 7 days later. Importantly, repeated JWH-018 exposure induced mitochondrial dysfunction in cardiomyocytes, i.e., defective lipid OXPHOS, which may represent one mechanism of JWH-018-induced toxicity. Our results demonstrate that repeated administration of even a relatively low dose of JWH-018 is sufficient to affect cardiovascular function and induce enduring toxicological consequences, pointing to risks associated with SCRA consumption.

Medical cannabis for refractory cancer-related pain in a specialised clinical service: a cross-sectional study

BACKGROUND AND OBJECTIVES

Cancer-related pain management in advanced stages presents a significant challenge that often requires a multidisciplinary approach. Although advancements in pharmacological and interventional therapies, a considerable number of patients still suffer from refractory pain, leading to unmet clinical needs. This study shares our experience with medical cannabis (MC) as a potential therapy for this specific population of patients with cancer-related refractory pain.

METHODS

In a cross-sectional study, 252 consecutive refractory cancer-related pain patients (mean age=61.71, SD=14.02, 47.6% males) filled out detailed self-report questionnaires. Of these, 126 patients (55%) were treated with MC and 105 patients (45%) were not.

RESULTS

Most patients received pain management from their oncologist, not a pain specialist. MC was mainly started for pain relief, sleep difficulties and anorexia. About 70% of patients reported subjective improvement from MC, with almost 40% reporting a significant improvement in coping with their illness. Side effects were generally mild, with fatigue and dizziness being the most common (21.78% and 23.46%, respectively). No patient required dedicated medical care for side effects. Of non-users, 65% had tried MC before and stopped due to lack of effectiveness or side effects (39.7% and 34.6%, respectively).

CONCLUSION

Refractory cancer pain necessitates innovative approaches. This registry highlights that MC can effectively improve symptoms in non-responsive patients, with favourable safety profiles for this vulnerable population.

Cannabinoids and triple-negative breast cancer treatment

Triple-negative breast cancer (TNBC) accounts for about 10-20% of all breast cancer cases and is associated with an unfavorable prognosis. Until recently, treatment options for TNBC were limited to chemotherapy. A new successful systemic treatment is immunotherapy with immune checkpoint inhibitors, but new tumor-specific biomarkers are needed to improve patient outcomes. Cannabinoids show antitumor activity in most preclinical studies in TNBC models and do not appear to have adverse effects on chemotherapy. Clinical data are needed to evaluate efficacy and safety in humans. Importantly, the endocannabinoid system is linked to the immune system and immunosuppression. Therefore, cannabinoid receptors could be a potential biomarker for immune checkpoint inhibitor therapy or a novel mechanism to reverse resistance to immunotherapy. In this article, we provide an overview of the currently available information on how cannabinoids may influence standard therapy in TNBC.

Cannabidiol (CBD) Inhibits Foam Cell Formation via Regulating Cholesterol Homeostasis and Lipid Metabolism

SCOPE

The cannabidiol (CBD) in hemp oil has important pharmacological activities. Accumulating evidence suggests that CBD is beneficial in the cardiovascular system and has been applied as a health supplement for atherosclerosis. However, the mechanism remains unclear.

METHODS AND RESULTS

This study investigates the impact of CBD on foam cell formation, cholesterol homeostasis, and lipid metabolism in macrophages. CBD elevates the levels of peroxisome proliferator-activated receptor gamma (PPARγ) and its associated targets, such as ATP binding transporter A1/G1 (ABCA1/ABCG1), thus reducing foam cell formation, and increasing cholesterol efflux within macrophages. Notably, the upregulation of ABCA1 and ABCG1 expression induced by CBD is found to be attenuated by both a PPARγ inhibitor and PPARγ small interfering RNA (siRNA). Moreover, transfection of PPARγ siRNA results in a decrease in the inhibitory effect of CBD on foam cell formation and promotion of cholesterol efflux. Through lipidomics analysis, the study finds that CBD significantly reverses the enhancement of ceramide (Cer). Correlation analysis indicates a negative association between Cer level and the expression of ABCA1/ABCG1.

CONCLUSION

This study confirms that CBD can be an effective therapeutic candidate for atherosclerosis treatment by activating PPARγ, up-regulating ABCA1/ABCG1 expression, and down-regulating Cer level.

Melanoma and cannabinoids: A possible chance for cancer treatment

The endocannabinoid system is composed by a complex and ubiquitous network of endogenous lipid ligands, enzymes for their synthesis and degradation, and receptors, which can also be stimulated by exogenous compounds, such as those derived from the Cannabis sativa. Cannabis and its bioactive compounds, including cannabinoids and non-cannabinoids, have been extensively studied in different conditions. Recent data have shown that the endocannabinoid system is responsible for maintaining the homeostasis of various skin functions such as proliferation, differentiation and release of inflammatory mediators. Because of their role in regulating these key processes, cannabinoids have been studied for the treatment of skin cancers and melanoma; their anti-tumour effects regulate skin cancer progression and are mainly related to the inhibition of tumour growth, proliferation, invasion and angiogenesis, through apoptosis and autophagy induction. This review aims at summarising the current field of research on the potential uses of cannabinoids in the melanoma field.

Cannabinoids: Potential for Modulation and Enhancement When Combined with Vitamin B12 in Case of Neurodegenerative Disorders

The enduring relationship between humanity and the cannabis plant has witnessed significant transformations, particularly with the widespread legalization of medical cannabis. This has led to the recognition of diverse pharmacological formulations of medical cannabis, containing 545 identified natural compounds, including 144 phytocannabinoids like Δ9-THC and CBD. Cannabinoids exert distinct regulatory effects on physiological processes, prompting their investigation in neurodegenerative diseases. Recent research highlights their potential in modulating protein aggregation and mitochondrial dysfunction, crucial factors in conditions such as Alzheimer's Disease, multiple sclerosis, or Parkinson's disease. The discussion emphasizes the importance of maintaining homeodynamics in neurodegenerative disorders and explores innovative therapeutic approaches such as nanoparticles and RNA aptamers. Moreover, cannabinoids, particularly CBD, demonstrate anti-inflammatory effects through the modulation of microglial activity, offering multifaceted neuroprotection including mitigating aggregation. Additionally, the potential integration of cannabinoids with vitamin B12 presents a holistic framework for addressing neurodegeneration, considering their roles in homeodynamics and nervous system functioning including the hippocampal neurogenesis. The potential synergistic therapeutic benefits of combining CBD with vitamin B12 underscore a promising avenue for advancing treatment strategies in neurodegenerative diseases. However, further research is imperative to fully elucidate their effects and potential applications, emphasizing the dynamic nature of this field and its potential to reshape neurodegenerative disease treatment paradigms.

Endocannabinoid System Changes throughout Life: Implications and Therapeutic Potential for Autism, ADHD, and Alzheimer's Disease

The endocannabinoid system has been linked to various physiological and pathological processes, because it plays a neuromodulator role in the central nervous system. In this sense, cannabinoids have been used off-label for neurodevelopmental disorders, such as autism spectrum disorder (ASD) and attention-deficit/hyperactivity disorder (ADHA), as well as in Alzheimer's disease (AD), a more prevalent neurodegenerative disease. Thus, this study aims, through a comprehensive literature review, to arrive at a better understanding of the impact of cannabinoids in the therapeutic treatment of patients with ASD, ADHD, and Alzheimer's disease (AD). Overall, cannabis products rich in CBD displayed a higher therapeutic potential for ASD children, while cannabis products rich in THC have been tested more for AD therapy. For ADHD, the clinical studies are incipient and inconclusive, but promising. In general, the main limitations of the clinical studies are the lack of standardization of the cannabis-based products consumed by the participants, a lack of scientific rigor, and the small number of participants.

In silico exploration of CB2 receptor agonist in the management of neuroinflammatory conditions by pharmacophore modeling

Endocannabinoid system plays a pivotal role in controlling neuroinflammation, and modulating this system may not only aid in managing symptoms of neurodegenerative diseases such as Alzheimer's disease, Parkinson's disease, Multiple sclerosis, Epilepsy, Central and Peripheral neuropathic pain, but also, have the potential to target these diseases at an early-stage. In the present study, six different pharmacophore hypotheses were generated from Cannabidiol (CBD)-Cannabinoid Receptor subtype-2 (CB2) and then Zinc database was screened for identification of hit molecules. Identified 215 hit molecules were subjected to preliminary screening with ADMET and drug likeness properties, and about 48 molecules were found with no violations and toxicity properties. In molecular docking studies, six compounds showed better binding energy than CBD and β-caryophyllene (known inhibitor of CB2). These six molecules were designated as leads and subjected to re-docking with glide tool and Lead1 (ZINC000078815430) showed docking score of -9.877 kcal/mol, whereas CBD and β-caryophyllene showed score of -9.664 and -8.499 kcal/mol, respectively. Lead1 and CBD were evaluated for stability studies with Desmond tool by molecular dynamic simulation studies. Lead1 showed better stability than CBD in all studied parameters such as RMSD, RMSF, SSE, Rg, SASA, etc. In MM-GBSA free energy calculations, ΔGbinding energy of CB2-CBD complex and CB2-Lead1 were found to be -103.13±11.19 and -107.94±5.42 kcal/mol, respectively. Six lead molecules stated in the study hold promise with respect to CBD agonistic activity for treating and/or managing chronic conditions and can be explored as an alternative for early-stage cure, which has not yet been experimentally explored.

Multi-Omics Reveals the Effects of Cannabidiol on Gut Microbiota and Metabolic Phenotypes

Introduction: Cannabidiol (CBD) has important pharmacological activity, which includes antispasmodic, antioxidant, antithrombotic, and antianxiety properties. CBD has been applied as a health supplement to atherosclerosis. However, CBDs effect on gut microbiota and metabolic phenotype is unclear. Materials and Methods: We constructed a high production of cardiovascular risk factors, such as trimethylamine-N-oxide (TMAO) and phenylacetylglutamine (PAGln), in a mouse model using Clostridium sporogenes colonization. We used 16S ribosomal RNA (rRNA) gene sequencing and ultra-high performance liquid chromatography-quadrupole time-of flight mass spectrometry-based metabolomics to evaluate the effect of CBD on gut microbiota and plasma metabolites. Results: CBD decreased the levels of creatine kinase (CK), alanine transaminase (ALT), and low-density lipoprotein cholesterol and markedly increased high-density lipoprotein cholesterol. Furthermore, CBD treatment increased the abundance of beneficial bacteria, which include Lachnospiraceae_NK4A136 and Blautia in the gut, but it decreased the levels of TMAO and PAGln in the plasma. Conclusion: CBD might have beneficial effects for cardiovascular protection.

Cannabinoid and Orexigenic Systems Interplay as a New Focus of Research in Alzheimer's Disease

Alzheimer's disease (AD) remains a significant health challenge, with an increasing prevalence globally. Recent research has aimed to deepen the understanding of the disease pathophysiology and to find potential therapeutic interventions. In this regard, G protein-coupled receptors (GPCRs) have emerged as novel potential therapeutic targets to palliate the progression of neurodegenerative diseases such as AD. Orexin and cannabinoid receptors are GPCRs capable of forming heteromeric complexes with a relevant role in the development of this disease. On the one hand, the hyperactivation of the orexins system has been associated with sleep-wake cycle disruption and Aβ peptide accumulation. On the other hand, cannabinoid receptor overexpression takes place in a neuroinflammatory environment, favoring neuroprotective effects. Considering the high number of interactions between cannabinoid and orexin systems that have been described, regulation of this interplay emerges as a new focus of research. In fact, in microglial primary cultures of APPSw/Ind mice model of AD there is an important increase in CB2R-OX1R complex expression, while OX1R antagonism potentiates the neuroprotective effects of CB2R. Specifically, pretreatment with the OX1R antagonist has been shown to strongly potentiate CB2R signaling in the cAMP pathway. Furthermore, the blockade of OX1R can also abolish the detrimental effects of OX1R overactivation in AD. In this sense, CB2R-OX1R becomes a new potential therapeutic target to combat AD.

Synthesis of novel indol-3-acetamido analogues as potent anticancer agents, biological evaluation and molecular modeling studies

Cannabinoids bind to cannabinoid receptors CB1 and CB2 and their antitumoral activity has been reported against some various cancer cell lines. Some synthetic cannabinoids possessing indole rings such as JWH-015 and JWH-133 particularly bind to the cannabinoid CB2 receptor and it was reported that they inhibit the proliferation and growth of various cancer cells without their psychoactive effects. However, the pharmacological action mechanisms of the cannabinoids are completely unknown. In this study, we report the synthesis of some new cannabinoidic novel indoles and evaluate their anticancer activity on various cancerous and normal cell lines (U87, RPMI 8226, HL60 and L929) using several cellular and molecular assays including MTT assay, real-time q-PCR, scratch assay, DAPI assay, Annexin V-PE/7AAD staining, caspase3/7 activity tests. Our findings indicated that compounds 7, 10, 13, 16, and 17 could reduce cell viability effectively. Compound 17 markedly increased proapoptotic genes (BAX, BAD, and BIM), tumor suppressor gene (p53) expression levels as well as the BAX/BCL-2 ratio in U87 cells. In addition, 17 inhibited cell migration. Based on these results, 17 was chosen for determining the mechanism of cell death in U87 cells. DAPI and Annexin V-7AAD staining results showed that 17 induced apoptosis, moreover activated caspase 3/7 significantly. Hence, compound 17, was selected as a lead compound for further pharmacomodulation. To rationalize the observed biological activities of 17, our study also included a comprehensive analysis using molecular docking and MD simulations. This integrative approach revealed that 17 fits tightly into the active site of the CB2 receptor and is involved in key interactions that may be responsible for its anti-proliferative effects.

Beyond prediction: unveiling the prognostic power of μ-opioid and cannabinoid receptors, alongside immune mediators, in assessing the severity of SARS-CoV-2 infection

BACKGROUND

This study aims to explore the potential of utilizing the expression levels of cannabinoid receptor 2 (CB2), μ-opioid receptor (MOR), MCP-1, IL-17, IFN-γ, and osteopontin as predictors for the severity of SARS-CoV-2 infection. The overarching goal is to delineate the pathogenic mechanisms associated with SARS-CoV-2.

METHODS

Using quantitative Real-time PCR, we analyzed the gene expression levels of CB2 and MOR in nasopharynx specimens obtained from patients diagnosed with SARS-CoV-2 infection, with 46 individuals classified as having severe symptoms and 46 as non-severe. Additionally, we measured the circulating levels of MCP-1, IL-17, IFN-γ, and osteopontin using an ELISA assay. We examined the predictive capabilities of these variables and explored their correlations across all patient groups.

RESULTS

Our results demonstrated a significant increase in MOR gene expression in the epithelium of patients with severe infection. The expression of CB2 receptor was also elevated in both male and female patients with severe symptoms. Furthermore, we observed concurrent rises in MCP-1, IL-17, IFN-γ, and osteopontin levels in patients, which were linked to disease severity. CB2, MOR, MCP-1, IL-17, IFN-γ, and osteopontin showed strong predictive abilities in distinguishing between patients with varying degrees of SARS-CoV-2 severity. Moreover, we identified a significant correlation between CB2 expression and the levels of MOR, MCP-1, osteopontin, and IFN-γ.

CONCLUSIONS

These results underline the interconnected nature of molecular mediators in a sequential manner, suggesting that their overexpression may play a role in the development of SARS-CoV-2 infections.

Natural Products Derived from Cannabis sativa for Pain Management

Cannabis sativa is one of the oldest medicinal plants in human history. Even ancient physicians from hundreds of years ago used Cannabis sativa to treat several conditions like pain. In the modern era, the research community, including health-care providers, have witnessed wide-scale changes in cannabis policy, legislation, and marketing, with a parallel increase in patient interest. A simple search in PubMed using "cannabis and pain" as keywords provides more than 2,400 articles, about 80% of which were published in the last 8-10 years. Several advancements have been achieved in understanding the complex chemistry of cannabis along with its multiple pharmacological activities. Preclinical data have demonstrated evidence for the promising potential of cannabis for pain management, and the continuous rise in the prevalence of pain increases the urgency to translate this into clinical practice. Despite the large body of cannabis literature, researchers still need to find rigorous answers for the questions about the efficacy and safety of cannabis in treatment of certain disorders such as pain. In the current chapter, we seek to present a critical overview about the current knowledge on cannabis with special emphasis on pain-related disorders.

Cardiotoxic effects of common and emerging drugs: role of cannabinoid receptors

Drug-induced cardiotoxicity has become one of the most common and detrimental health concerns, which causes significant loss to public health and drug resources. Cannabinoid receptors (CBRs) have recently achieved great attention for their vital roles in the regulation of heart health and disease, with mounting evidence linking CBRs with the pathogenesis and progression of drug-induced cardiotoxicity. This review aims to summarize fundamental characteristics of two well-documented CBRs (CB1R and CB2R) from aspects of molecular structure, signaling and their functions in cardiovascular physiology and pathophysiology. Moreover, we describe the roles of CB1R and CB2R in the occurrence of cardiotoxicity induced by common drugs such as antipsychotics, anti-cancer drugs, marijuana, and some emerging synthetic cannabinoids. We highlight the 'yin-yang' relationship between CB1R and CB2R in drug-induced cardiotoxicity and propose future perspectives for CBR-based translational medicine toward cardiotoxicity curation and clinical monitoring.

Role of Cannabinoids in Oral Cancer

Cannabinoids have incited scientific interest in different conditions, including malignancy, due to increased exposure to cannabis. Furthermore, cannabinoids are increasingly used to alleviate cancer-related symptoms. This review paper aims to clarify the recent findings on the relationship between cannabinoids and oral cancer, focusing on the molecular mechanisms that could link cannabinoids with oral cancer pathogenesis. In addition, we provide an overview of the current and future perspectives on the management of oral cancer patients using cannabinoid compounds. Epidemiological data on cannabis use and oral cancer development are conflicting. However, in vitro studies assessing the effects of cannabinoids on oral cancer cells have unveiled promising anti-cancer features, including apoptosis and inhibition of cell proliferation. Downregulation of various signaling pathways with anti-cancer effects has been identified in experimental models of oral cancer cells exposed to cannabinoids. Furthermore, in some countries, several synthetic or phytocannabinoids have been approved as medical adjuvants for the management of cancer patients undergoing chemoradiotherapy. Cannabinoids may improve overall well-being by relieving anxiety, depression, pain, and nausea. In conclusion, the link between cannabinoid compounds and oral cancer is complex, and further research is necessary to elucidate the potential risks or their protective impact on oral cancer.

Involvement of Cannabinoid Receptors and Adenosine A2B Receptor in Enhanced Migration of Lung Cancer A549 Cells Induced by γ-Ray Irradiation

Residual cancer cells after radiation therapy may acquire malignant phenotypes such as enhanced motility and migration ability, and therefore it is important to identify targets for preventing radiation-induced malignancy in order to increase the effectiveness of radiotherapy. G-Protein-coupled receptors (GPCRs) such as adenosine A2B receptor and cannabinoid receptors (CB1, CB2, and GPR55) may be involved, as they are known to have roles in proliferation, invasion, migration and tumor growth. In this study, we investigated the involvement of A2B and cannabinoid receptors in γ-radiation-induced enhancement of cell migration and actin remodeling, as well as the involvement of cannabinoid receptors in cell migration enhancement via activation of A2B receptor in human lung cancer A549 cells. Antagonists or knockdown of A2B, CB1, CB2, or GPR55 receptor suppressed γ-radiation-induced cell migration and actin remodeling. Furthermore, BAY60-6583 (an A2B receptor-specific agonist) enhanced cell migration and actin remodeling in A549 cells, and this enhancement was suppressed by antagonists or knockdown of CB2 or GPR55, though not CB1 receptor. Our results indicate that A2B receptors and cannabinoid CB1, CB2, and GPR55 receptors all contribute to γ-radiation-induced acquisition of malignant phenotypes, and in particular that interactions of A2B receptor and cannabinoid CB2 and GPR55 receptors play a role in promoting cell migration and actin remodeling. A2B receptor-cannabinoid receptor pathways may be promising targets for blocking the appearance of malignant phenotypes during radiotherapy of lung cancer.

Allosteric crosstalk in modular proteins: Function fine-tuning and drug design

Modular proteins are regulatory proteins that carry out more than one function. These proteins upregulate or downregulate a biochemical cascade to establish homeostasis in cells. To switch the function or alter the efficiency (based on cellular needs), these proteins require different facilitators that bind to a site different from the catalytic (active/orthosteric) site, aka 'allosteric site', and fine-tune their function. These facilitators (or effectors) are allosteric modulators. In this Review, we have discussed the allostery, characterized them based on their mechanisms, and discussed how allostery plays an important role in the activity modulation and function fine-tuning of proteins. Recently there is an emergence in the discovery of allosteric drugs. We have also emphasized the role, significance, and future of allostery in therapeutic applications.

Supraphysiologic doses of 17β-estradiol aggravate depression-like behaviors in ovariectomized mice possibly via regulating microglial responses and brain glycerophospholipid metabolism

BACKGROUND

17β-Estradiol (E2) is generally considered neuroprotective in humans. However, the current clinical use of estrogen replacement therapy (ERT) is based on the physiological dose of E2 to treat menopausal syndrome and has limited therapeutic efficacy. The efficacy and potential toxicity of superphysiological doses of ERT for menopausal neurodegeneration are unknown.

METHODS

In this study, we investigated the effect of E2 with a supraphysiologic dose (0.5 mg/kg, sE2) on the treatment of menopausal mouse models established by ovariectomy. We performed the open field, Y-maze spontaneous alternation, forced swim tests, and sucrose preference test to investigate behavioral alterations. Subsequently, the status of microglia and neurons was detected by immunohistochemistry, HE staining, and Nissl staining, respectively. Real-time PCR was used to detect neuroinflammatory cytokines in the hippocampus and cerebral cortex. Using mass spectrometry proteomics platform and LC-MS/ MS-based metabolomics platform, proteins and metabolites in brain tissues were extracted and analyzed. BV2 and HT22 cell lines and primary neurons and microglia were used to explore the underlying molecular mechanisms in vitro.

RESULTS

sE2 aggravated depression-like behavior in ovariectomized mice, caused microglia response, and increased proinflammatory cytokines in the cerebral cortex and hippocampus, as well as neuronal damage and glycerophospholipid metabolism imbalance. Subsequently, we demonstrated that sE2 induced the pro-inflammatory phenotype of microglia through ERα/NF-κB signaling pathway and downregulated the expression of cannabinoid receptor 1 in neuronal cells, which were important in the pathogenesis of depression.

CONCLUSION

These data suggest that sE2 may be nonhelpful or even detrimental to menopause-related depression, at least partly, by regulating microglial responses and glycerophospholipid metabolism.

Opportunities and challenges in drug discovery targeting the orphan receptor GPR12

G-protein-coupled receptor 12 (GPR12) is a brain-specific expression orphan G-protein-coupled receptor (oGPCR) that regulates various physiological processes. It is an emerging therapeutic target for central nervous system (CNS) disorders, including Alzheimer's disease (AD), Parkinson's disease (PD), Huntington's disease (HD), attention deficit hyperactivity disorder (ADHD), and schizophrenia, as well as other human diseases, such as cancer, obesity, and metabolic disorders. GPR12 remains a less extensively investigated oGPCR, particularly in terms of its biological functions, signaling pathways, and ligand discovery. The discovery of drug-like small-molecule modulators to probe the brain functions of GPR12 or to act as a potential drug candidates, as well as the identification of reliable biomarkers, are vital to elucidate the roles of this receptor in various human diseases and develop novel target-based therapeutics.

Roadmap For The Expression Of Canonical and Extended Endocannabinoid System Receptors and Proteins in Peripheral Organs of Preclinical Animal Models

The endocannabinoid system is widely expressed throughout the body and is comprised of receptors, ligands, and enzymes that maintain metabolic, immune, and reproductive homeostasis. Increasing interest in the endocannabinoid system has arisen due to these physiologic roles, policy changes leading to more widespread recreational use, and the therapeutic potential of Cannabis and phytocannabinoids. Rodents have been the primary preclinical model of focus due to their relative low cost, short gestational period, genetic manipulation strategies, and gold-standard behavioral tests. However, the potential for lack of clinical translation to non-human primates and humans is high as cross-species comparisons of the endocannabinoid system has not been evaluated. To bridge this gap in knowledge, we evaluate the relative gene expression of 14 canonical and extended endocannabinoid receptors in seven peripheral organs of C57/BL6 mice, Sprague-Dawley rats, and non-human primate rhesus macaques. Notably, we identify species- and organ-specific heterogeneity in endocannabinoid receptor distribution where there is surprisingly limited overlap among the preclinical models. Importantly, we determined there were only five receptors (CB2, GPR18, GPR55, TRPV2, and FAAH) that had identical expression patterns in mice, rats, and rhesus macaques. Our findings demonstrate a critical, yet previously unappreciated, contributor to challenges of rigor and reproducibility in the cannabinoid field, which has profound implications in hampering progress in understanding the complexity of the endocannabinoid system and development of cannabinoid-based therapies.

Cannabis-based medicines and medical cannabis for adults with cancer pain

BACKGROUND

Pain is a common symptom in people with cancer; 30% to 50% of people with cancer will experience moderate-to-severe pain. This can have a major negative impact on their quality of life. Opioid (morphine-like) medications are commonly used to treat moderate or severe cancer pain, and are recommended for this purpose in the World Health Organization (WHO) pain treatment ladder. Pain is not sufficiently relieved by opioid medications in 10% to 15% of people with cancer. In people with insufficient relief of cancer pain, new analgesics are needed to effectively and safely supplement or replace opioids.

OBJECTIVES

To evaluate the benefits and harms of cannabis-based medicines, including medical cannabis, for treating pain and other symptoms in adults with cancer compared to placebo or any other established analgesic for cancer pain.

SEARCH METHODS

We used standard, extensive Cochrane search methods. The latest search date was 26 January 2023.

SELECTION CRITERIA

We selected double-blind randomised, controlled trials (RCT) of medical cannabis, plant-derived and synthetic cannabis-based medicines against placebo or any other active treatment for cancer pain in adults, with any treatment duration and at least 10 participants per treatment arm.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methods. The primary outcomes were 1. proportions of participants reporting no worse than mild pain; 2. Patient Global Impression of Change (PGIC) of much improved or very much improved and 3. withdrawals due to adverse events. Secondary outcomes were 4. number of participants who reported pain relief of 30% or greater and overall opioid use reduced or stable; 5. number of participants who reported pain relief of 30% or greater, or 50% or greater; 6. pain intensity; 7. sleep problems; 8. depression and anxiety; 9. daily maintenance and breakthrough opioid dosage; 10. dropouts due to lack of efficacy; 11. all central nervous system adverse events. We used GRADE to assess certainty of evidence for each outcome.

MAIN RESULTS

We identified 14 studies involving 1823 participants. No study assessed the proportions of participants reporting no worse than mild pain on treatment by 14 days after start of treatment. We found five RCTs assessing oromucosal nabiximols (tetrahydrocannabinol (THC) and cannabidiol (CBD)) or THC alone involving 1539 participants with moderate or severe pain despite opioid therapy. The double-blind periods of the RCTs ranged between two and five weeks. Four studies with a parallel design and 1333 participants were available for meta-analysis. There was moderate-certainty evidence that there was no clinically relevant benefit for proportions of PGIC much or very much improved (risk difference (RD) 0.06, 95% confidence interval (CI) 0.01 to 0.12; number needed to treat for an additional beneficial outcome (NNTB) 16, 95% CI 8 to 100). There was moderate-certainty evidence for no clinically relevant difference in the proportion of withdrawals due to adverse events (RD 0.04, 95% CI 0 to 0.08; number needed to treat for an additional harmful outcome (NNTH) 25, 95% CI 16 to endless). There was moderate-certainty evidence for no difference between nabiximols or THC and placebo in the frequency of serious adverse events (RD 0.02, 95% CI -0.03 to 0.07). There was moderate-certainty evidence that nabiximols and THC used as add-on treatment for opioid-refractory cancer pain did not differ from placebo in reducing mean pain intensity (standardised mean difference (SMD) -0.19, 95% CI -0.40 to 0.02). There was low-certainty evidence that a synthetic THC analogue (nabilone) delivered over eight weeks was not superior to placebo in reducing pain associated with chemotherapy or radiochemotherapy in people with head and neck cancer and non-small cell lung cancer (2 studies, 89 participants, qualitative analysis). Analyses of tolerability and safety were not possible for these studies. There was low-certainty evidence that synthetic THC analogues were superior to placebo (SMD -0.98, 95% CI -1.36 to -0.60), but not superior to low-dose codeine (SMD 0.03, 95% CI -0.25 to 0.32; 5 single-dose trials; 126 participants) in reducing moderate-to-severe cancer pain after cessation of previous analgesic treatment for three to four and a half hours (2 single-dose trials; 66 participants). Analyses of tolerability and safety were not possible for these studies. There was low-certainty evidence that CBD oil did not add value to specialist palliative care alone in the reduction of pain intensity in people with advanced cancer. There was no difference in the number of dropouts due to adverse events and serious adverse events (1 study, 144 participants, qualitative analysis). We found no studies using herbal cannabis.

AUTHORS' CONCLUSIONS

There is moderate-certainty evidence that oromucosal nabiximols and THC are ineffective in relieving moderate-to-severe opioid-refractory cancer pain. There is low-certainty evidence that nabilone is ineffective in reducing pain associated with (radio-) chemotherapy in people with head and neck cancer and non-small cell lung cancer. There is low-certainty evidence that a single dose of synthetic THC analogues is not superior to a single low-dose morphine equivalent in reducing moderate-to-severe cancer pain. There is low-certainty evidence that CBD does not add value to specialist palliative care alone in the reduction of pain in people with advanced cancer.

Novel GPR18 Ligands in Rodent Pharmacological Tests: Effects on Mood, Pain, and Eating Disorders

The lack of selective pharmacological tools has limited the full unraveling of G protein-coupled receptor 18 (GPR18) functions. The present study was aimed at discovering the activities of three novel preferential or selective GPR18 ligands, one agonist (PSB-KK-1415) and two antagonists (PSB-CB-5 and PSB-CB-27). We investigated these ligands in several screening tests, considering the relationship between GPR18 and the cannabinoid (CB) receptor system, and the control of endoCB signaling over emotions, food intake, pain sensation, and thermoregulation. We also assessed whether the novel compounds could modulate the subjective effects evoked by Δ⁹-tetrahydrocannabinol (THC). Male mice or rats were pretreated with the GPR18 ligands, and locomotor activity, depression- and anxiety-like symptoms, pain threshold, core temperature, food intake, and THC-vehicle discrimination were measured. Our screening analyses indicated that GPR18 activation partly results in effects that are similar to those of CB receptor activation, considering the impact on emotional behavior, food intake, and pain activity. Thus, the orphan GPR18 may provide a novel therapeutic target for mood, pain, and/or eating disorders, and further investigation is warranted to better discern its function.

Development of Yin-Yang ligand for cannabinoid receptors

Cannabinoid receptors (CBs), including CB1 and CB2, are the key components of a lipid signaling endocannabinoid system (ECS). Development of synthetic cannabinoids has been attractive to modulate ECS functions. CB1 and CB2 are structurally closely related subtypes but with distinct functions. While most efforts focus on the development of selective ligands for single subtype to circumvent the undesired off-target effect, Yin-Yang ligands with opposite pharmacological activities simultaneously on two subtypes, offer unique therapeutic potential. Herein we report the development of a new Yin-Yang ligand which functions as an antagonist for CB1 and concurrently an agonist for CB2. We found that in the pyrazole-cored scaffold, the arm of N1-phenyl group could be a switch, modification of which yielded various ligands with distinct activities. As such, the ortho-morpholine substitution exerted the desired Yin-Yang bifunctionality which, based on the docking study and molecular dynamic simulation, was proposed to be resulted from the hydrogen bonding with S173 and S285 in CB1 and CB2, respectively. Our results demonstrated the feasibility of structure guided ligand evolution for challenging Yin-Yang ligand.

Cannabis sativa: A look at protozoa, helminths, insect vectors, and pests

Active principles extracted from plants, such as essential oils, have been commonly described in the literature as therapeutic targets for numerous pathological conditions. Cannabis sativa, which has an ancient and peculiar history, has been used for various purposes, from recreational to compounds of pharmacotherapeutic and industrial importance, such as pesticides based on this plant. It is a plant that contains approximately 500 described cannabinoid compounds and is the target of in vitro and in vivo studies at different locations. This review clarifies the role of cannabinoid compounds in parasitic infections caused by helminths and protozoa. In addition, this study briefly presented the use of C. sativa constituents in the formulation of pesticides for vector control, as the latter topic is justified by the economic burden faced by several regions where vector-borne diseases are a troubling reality. Studies involving cannabis compounds with pesticidal potential should be encouraged, especially those that evaluate their effectiveness against the different life cycles of insects, seeking to interrupt vector proliferation after egg laying. Actions aimed at the management and cultivation of plant species with ecologically correct pharmacotherapeutic and pesticide potentials are becoming urgent.

Endocannabinoid System: Chemical Characteristics and Biological Activity

The endocannabinoid system (eCB) has been studied to identify the molecular structures present in Cannabis sativa. eCB consists of cannabinoid receptors, endogenous ligands, and the associated enzymatic apparatus responsible for maintaining energy homeostasis and cognitive processes. Several physiological effects of cannabinoids are exerted through interactions with various receptors, such as CB1 and CB2 receptors, vanilloid receptors, and the recently discovered G-protein-coupled receptors (GPR55, GPR3, GPR6, GPR12, and GPR19). Anandamide (AEA) and 2-arachidoylglycerol (2-AG), two small lipids derived from arachidonic acid, showed high-affinity binding to both CB1 and CB2 receptors. eCB plays a critical role in chronic pain and mood disorders and has been extensively studied because of its wide therapeutic potential and because it is a promising target for the development of new drugs. Phytocannabinoids and synthetic cannabinoids have shown varied affinities for eCB and are relevant to the treatment of several neurological diseases. This review provides a description of eCB components and discusses how phytocannabinoids and other exogenous compounds may regulate the eCB balance. Furthermore, we show the hypo- or hyperfunctionality of eCB in the body and how eCB is related to chronic pain and mood disorders, even with integrative and complementary health practices (ICHP) harmonizing the eCB.

The endocannabinoid system and breathing

Recent changes in cannabis accessibility have provided adjunct therapies for patients across numerous disease states and highlights the urgency in understanding how cannabinoids and the endocannabinoid (EC) system interact with other physiological structures. The EC system plays a critical and modulatory role in respiratory homeostasis and pulmonary functionality. Respiratory control begins in the brainstem without peripheral input, and coordinates the preBötzinger complex, a component of the ventral respiratory group that interacts with the dorsal respiratory group to synchronize burstlet activity and drive inspiration. An additional rhythm generator: the retrotrapezoid nucleus/parafacial respiratory group drives active expiration during conditions of exercise or high CO₂. Combined with the feedback information from the periphery: through chemo- and baroreceptors including the carotid bodies, the cranial nerves, stretch of the diaphragm and intercostal muscles, lung tissue, and immune cells, and the cranial nerves, our respiratory system can fine tune motor outputs that ensure we have the oxygen necessary to survive and can expel the CO₂ waste we produce, and every aspect of this process can be influenced by the EC system. The expansion in cannabis access and potential therapeutic benefits, it is essential that investigations continue to uncover the underpinnings and mechanistic workings of the EC system. It is imperative to understand the impact cannabis, and exogenous cannabinoids have on these physiological systems, and how some of these compounds can mitigate respiratory depression when combined with opioids or other medicinal therapies. This review highlights the respiratory system from the perspective of central versus peripheral respiratory functionality and how these behaviors can be influenced by the EC system. This review will summarize the literature available on organic and synthetic cannabinoids in breathing and how that has shaped our understanding of the role of the EC system in respiratory homeostasis. Finally, we look at some potential future therapeutic applications the EC system has to offer for the treatment of respiratory diseases and a possible role in expanding the safety profile of opioid therapies while preventing future opioid overdose fatalities that result from respiratory arrest or persistent apnea.

Endocannabinoid-Binding Receptors as Drug Targets

Cannabis plant has been used from ancient times with therapeutic purposes for treating human pathologies, but the identification of the cellular and molecular mechanisms underlying the therapeutic properties of the phytocannabinoids, the active compounds in this plant, occurred in the last years of the past century. In the late 1980s and early 1990s, seminal studies demonstrated the existence of cannabinoid receptors and other elements of the so-called endocannabinoid system. These G protein-coupled receptors (GPCRs) are a key element in the functions assigned to endocannabinoids and appear to serve as promising pharmacological targets. They include CB₁, CB₂, and GPR55, but also non-GPCRs can be activated by endocannabinoids, like ionotropic receptor TRPV₁ and even nuclear receptors of the PPAR family. Their activation, inhibition, or simply modulation have been associated with numerous physiological effects at both central and peripheral levels, which may have therapeutic value in different human pathologies, then providing a solid experimental explanation for both the ancient medicinal uses of Cannabis plant and the recent advances in the development of cannabinoid-based specific therapies. This chapter will review the scientific knowledge generated in the last years around the research on the different endocannabinoid-binding receptors and their signaling mechanisms. Our intention is that this knowledge may help readers to understand the relevance of these receptors in health and disease conditions, as well as it may serve as the theoretical basis for the different experimental protocols to investigate these receptors and their signaling mechanisms that will be described in the following chapters.

Identification of a potential structure-based GPCR drug for interstitial cystitis/bladder pain syndrome: in silico protein structure analysis and molecular docking

INTRODUCTION AND HYPOTHESIS

There is currently no effective treatment for interstitial cystitis / bladder pain syndrome (IC/BPS) and thus seriously reduces the quality of life of patients. The purpose of this study is to analyze the structure and function of G protein coupled receptors related to IC/BPS by integrating bioinformatics and provide basis for the development of new drugs for IC/BPS.

METHODS

We used ProtParam and DNAMAN to analyze the physical and chemical properties of GPR18 and GPR183 proteins. The secondary and tertiary structure, conservative domain, phosphorylation site of both proteins were predicted by ProtScale, PredictProtein, SWISS-MODEL and GPS5.0 respectively. Multiple sequence alignment of the proteins were carried out by DNAMAN and the phylogenetic tree was constructed by MEGA. Further, the molecular docking verification of cannabidiol and both proteins were carried out by using AutoDock Vin.

RESULTS

GPR18 and GPR183 proteins were composed of 331 and 361 amino acids respectively. α-helix is the highest in the secondary structure of the two proteins. Both proteins contain seven transmembrane domains specific to G protein coupled receptors. And homology analysis showed that the two proteins had high homology. In terms of molecular docking, cannabidiol, a non psychoactive component extracted from the cannabis, can form effective molecular binding with GPR18 and GPR183 proteins.

CONCLUSIONS

We identified the structures of GPR18 and GPR183 proteins and their highly homologous evolutionary properties. Furthermore, both proteins can form effective binding with cannabidiol which provides new insights for the development of IC/BPS drugs by targeting G protein coupled receptors.

Cannabinoids as Immune System Modulators: Cannabidiol Potential Therapeutic Approaches and Limitations

Introduction: Cannabidiol (CBD) is the second most abundant Phytocannabinoid in Cannabis extracts. CBD has a binding affinity for several cannabinoid and cannabinoid-associated receptors. Epidiolex (oral CBD solution) has been lately licensed by the Food and Drug Administration (FDA) for the treatment of pediatric epileptic seizures. Methods: In this review, we discussed the most promising applications of CBD for chronic inflammatory conditions, namely CBD's anti-inflammatory effects during inflammatory bowel disease, coronavirus disease (antiviral effect), brain pathologies (neuroprotective and anti-inflammatory properties), as well as CBD immunomodulatory and antitumoral activities in the tumor microenvironment. Special focus was shed on the main therapeutic mechanisms of action of CBD, particularly in the control of the immune system and the endocannabinoid system. Results: Findings suggest that CBD is a potent immunomodulatory drug as it has manifested immunosuppressive properties in the context of sterile inflammation (e.g., inflammatory bowel disease, rheumatoid arthritis, and neurodegenerative diseases), and immunoprotective effects during viral infections (e.g. COVID-19) Similarly, CBD has exhibited a selective response toward cancer types by engaging different targets and signaling pathways. These results are in favor of the primary function of the endocannabinoid system which is homeostatic maintenance. Conclusion: The presented evidence suggests that the endocannabinoid system is a prominent target for the treatment of inflammatory and autoimmune diseases, rheumatoid diseases, viral infections, neurological and psychological pathologies, and cancer. Moreover, the antitumoral activities of CBD have been suggested to be potentially used in combination with chemo- or immunotherapy during cancer. However, clinical results are still lacking, which raises a challenge to apply translational cannabis research to the human immune system.

Examining the role of cannabinoids on osteoporosis: a review

PURPOSE

Prior research studies have shown that the endocannabinoid system, influenced by CBD and THC, plays a role in bone remodeling. As both the research on cannabis and use of cannabis continue to grow, novel medicinal uses of both its constituents as well as the whole plant are being discovered. This review examines the role of cannabinoids on osteoporosis, more specifically, the endocannabinoid system and its role in bone remodeling and the involvement of the cannabinoid receptors 1 and 2 in bone health, as well as the effects of Δ9-tetrahydrocannabinol (THC), cannabidiol (CBD), and synthetic cannabinoids on bone.

METHODS

A comprehensive literature search of online databases including PUBMED was utilized.

RESULTS

A total of 29 studies investigating the effects of cannabis and/or its constituents as well as the activation or inactivation of cannabinoid receptors 1 and 2 were included and discussed.

CONCLUSION

While many of the mechanisms are still not yet fully understood, both preclinical and clinical studies show that the effects of cannabis mediated through the endocannabinoid system may prove to be an effective treatment option for individuals with osteoporosis.

Recent Advances in Endocannabinoid System Targeting for Improved Specificity: Strategic Approaches to Targeted Drug Delivery

Opportunities for developing innovative and intelligent drug delivery technologies by targeting the endocannabinoid system are becoming more apparent. This review provides an overview of strategies to develop targeted drug delivery using the endocannabinoid system (ECS). Recent advances in endocannabinoid system targeting showcase enhanced pharmaceutical therapy specificity while minimizing undesirable side effects and overcoming formulation challenges associated with cannabinoids. This review identifies advances in targeted drug delivery technologies that may permit access to the full pharmacotherapeutic potential of the ECS. The design of optimized nanocarriers that target specific tissues can be improved by understanding the nature of the signaling pathways, distribution in the mammalian body, receptor structure, and enzymatic degradation of the ECS. A closer look at ligand-receptor complexes, endocannabinoid tone, tissue distribution, and G-protein activity leads to a better understanding of the potential of the ECS toolkit for therapeutics. The signal transduction pathways examine the modulation of downstream effector proteins, desensitization, signaling cascades, and biased signaling. An in-depth and overall view of the targeted system is achieved through homology modeling where mutagenesis and ligand binding examine the binding site and allow sequence analysis and the formation of libraries for molecular docking and molecular dynamic simulations. Internalization routes exploring receptor-mediated endocytosis and lipid rafts are also considered for explicit signaling. Furthermore, the review highlights nanotechnology and surface modification aspects as a possible future approach for specific targeting.

Immune challenges upregulate the expression of cannabinoid receptors in cultured human odontoblasts and gingival fibroblasts

Odontoblasts and gingival fibroblasts play essential roles in the physiological and pathological processes of dental tissue. Cannabinoid receptors (CB1 and CB2) are involved in analgesia by modulating the función of calcium channels that inhibit the synthesis of some neurotransmitters. A better understanding of the physiology of these receptors would provide the possibility of using them as therapeutic targets in controlling dental pain. The aim of this study was to evaluate the presence and activity of cannabinoid receptors in human odontoblast-like cells (OLC) and human gingival fibroblasts (HGF). CB1 and CB2 transcription was analyzed by real-time PCR, proteins were detected by immunofluorescence, and functional cannabinoid receptors were evaluated by measuring intracellular calcium concentration after stimulation with cannabidiol (CBD) and pre-treatment with a CB1 antagonist, a CB2 inverse agonist and a TRPV1 antagonist. Transcripts for CB1 and CB2 were found in both odontoblasts and gingival fibroblasts. Cannabidiol induced an increase in [Ca2+]i in both cells types, but surprisingly, pre-treatment with selective cannabinoid antagonists attenuated this effect, suggesting a functional communication between specific cannabinoid receptors and other CBD target receptors. In conclusion, human odontoblasts and gingival fibroblasts express functional CB1 and CB2 cannabinoid receptors, which could be modulated to improve the treatment of pain or dental sensitivity.

WIN55212-2 Modulates Intracellular Calcium via CB1 Receptor-Dependent and Independent Mechanisms in Neuroblastoma Cells

The CB1 cannabinoid receptor (CB1R) and extracellular calcium (eCa2+)-stimulated Calcium Sensing receptor (CaSR) can exert cellular signaling by modulating levels of intracellular calcium ([Ca2+]i). We investigated the mechanisms involved in the ([Ca2+]i) increase in N18TG2 neuroblastoma cells, which endogenously express both receptors. Changes in [Ca2+]i were measured in cells exposed to 0.25 or 2.5 mM eCa2+ by a ratiometric method (Fura-2 fluorescence) and expressed as the difference between baseline and peak responses (ΔF340/380). The increased ([Ca2+]i) in cells exposed to 2.5 mM eCa2+ was blocked by the CaSR antagonist, NPS2143, this inhibition was abrogated upon stimulation with WIN55212-2. WIN55212-2 increased [Ca2+]i at 0.25 and 2.5 mM eCa2+ by 700% and 350%, respectively, but this increase was not replicated by CP55940 or methyl-anandamide. The store-operated calcium entry (SOCE) blocker, MRS1845, attenuated the WIN55212-2-stimulated increase in [Ca2+]i at both levels of eCa2+. Simultaneous perfusion with the CB1 antagonist, SR141716 or NPS2143 decreased the response to WIN55212-2 at 0.25 mM but not 2.5 mM eCa2+. Co-perfusion with the non-CB1/CB2 antagonist O-1918 attenuated the WIN55212-2-stimulated [Ca2+]i increase at both eCa2+ levels. These results are consistent with WIN55212-2-mediated intracellular Ca2+ mobilization from store-operated calcium channel-filled sources that could occur via either the CB1R or an O-1918-sensitive non-CB1R in coordination with the CaSR. Intracellular pathway crosstalk or signaling protein complexes may explain the observed effects.

Practical Considerations for the Use of Cannabis in Cancer Pain Management—What a Medical Oncologist Should Know

Pain is a highly debilitating emotional and sensory experience that significantly affects quality of life (QoL). Numerous chronic conditions, including cancer, are associated with chronic pain. In the setting of malignancy, pain can be a consequence of the tumor itself or of life-saving interventions, including surgery, chemotherapy, and radiotherapy. Despite significant pharmacological advances and awareness campaigns, pain remains undertreated in one-third of patients. To date, opioids have been the mainstay of cancer pain management. The problematic side effects and unsatisfactory pain relief of opioids have revived patients’ and physicians’ interest in finding new solutions, including cannabis and cannabinoids. The medical use of cannabis has been prohibited for decades, and it remains in Schedule 1 of the Misuse of Drugs Regulations. Currently, the legal context for its usage has become more permissive. Various preclinical and observational studies have aimed to prove that cannabinoids could be effective in cancer pain management. However, their clinical utility must be further supported by high-quality clinical trials.

Cannabinoids and PPAR Ligands: The Future in Treatment of Polycystic Ovary Syndrome Women with Obesity and Reduced Fertility

Cannabinoids (CBs) are used to treat chronic pain, chemotherapy-induced nausea and vomiting, and multiple sclerosis spasticity. Recently, the medicinal use of CBs has attracted increasing interest as a new therapeutic in many diseases. Data indicate a correlation between CBs and PPARs via diverse mechanisms. Both the endocannabinoid system (ECS) and peroxisome proliferator-activated receptors (PPARs) may play a significant role in PCOS and PCOS related disorders, especially in disturbances of glucose-lipid metabolism as well as in obesity and fertility. Taking into consideration the ubiquity of PCOS in the human population, it seems indispensable to search for new potential therapeutic targets for this condition. The aim of this review is to examine the relationship between metabolic disturbances and obesity in PCOS pathology. We discuss current and future therapeutic interventions for PCOS and related disorders, with emphasis on the metabolic pathways related to PCOS pathophysiology. The link between the ECS and PPARs is a promising new target for PCOS, and we examine this relationship in depth.

Review of delta-8-tetrahydrocannabinol (Δ8 -THC): Comparative pharmacology with Δ9 -THC

The use of the intoxicating cannabinoid delta-8-tetrahydrocannabinol (Δ⁸ -THC) has grown rapidly over the last several years. There have been dozens of Δ⁸ -THC studies dating back over many decades, yet no review articles have comprehensively covered these findings. In this review, we summarize the pharmacological studies of Δ⁸ -THC, including receptor binding, cell signalling, in vivo cannabimimetic activity, clinical activity and pharmacokinetics. We give special focus to studies that directly compared Δ⁸ -THC to its more commonly studied isomer, Δ⁹ -THC. Overall, the pharmacokinetics and pharmacodynamics of Δ⁸ -THC and Δ⁹ -THC are very similar. Δ⁸ -THC is a partial agonist of the cannabinoid CB₁ receptor and has cannabimimetic activity in both animals and humans. The reduced potency of Δ⁸ -THC in clinical studies compared with Δ⁹ -THC can be explained by weaker cannabinoid CB₁ receptor affinity, although there are other plausible mechanisms that may contribute. We highlight the gaps in our knowledge of Δ⁸ -THC pharmacology where further studies are needed, particularly in humans.

Curcumin, Resveratrol and Cannabidiol as Natural Key Prototypes in Drug Design for Neuroprotective Agents

Nowadays, neurodegenerative diseases (NDs), such as Parkinson's disease (PD), Alzheimer's disease (AD), Huntington's disease (HD), and amyotrophic lateral sclerosis (ALS), represent a great challenge in different scientific fields, such as neuropharmacology, medicinal chemistry, molecular biology and medicine, as all these pathologies remain incurable, with high socioeconomic impacts and high costs for governmental health services. Due to their severity and multifactorial pathophysiological complexity, the available approved drugs for clinic have not yet shown adequate effectiveness and exhibited very restricted options in the therapeutic arsenal; this highlights the need for continued drug discovery efforts in the academia and industry. In this context, natural products, such as curcumin (1), resveratrol (2) and cannabidiol (CBD, 3) have been recognized as important sources, with promising chemical entities, prototype models and starting materials for medicinal organic chemistry, as their molecular architecture, multifunctional properties and single chemical diversity could facilitate the discovery, optimization and development of innovative drug candidates with improved pharmacodynamics and pharmacokinetics compared to the known drugs and, perhaps, provide a chance for discovering novel effective drugs to combat NDs. In this review, we report the most recent efforts of medicinal chemists worldwide devoted to the exploration of curcumin (1), resveratrol (2) and cannabidiol (CBD, 3) as starting materials or privileged scaffolds in the design of multi-target directed ligands (MTDLs) with potential therapeutic properties against NDs, which have been published in the scientific literature during the last 10 years of research and are available in PubMed, SCOPUS and Web of Science databases.

Comparative Analysis of Fat Composition in Marrow, Serum, and Muscle from Aging C57BL6 mice

Osteosarcopenia is an age-related condition characterized by fragile bone and low muscle mass and function. Fat infiltration concomitantly contributes to age-related bone and muscle decline. Fat-secreted factors could be locally secreted in the muscle and bone marrow milieu affecting cell function and survival. However, the specific fat-related secretory factors that may simultaneously affect those tissues remain unknown. Using targeted-lipidomics approach, we comprehensively quantified fat composition (lipid mediators [LMs]) in bone marrow flush, gastrocnemius and serum obtained from 6-, 24- and 42-week-old C57BL6 mice. Compared to young mice (6wks), all tissues in older mice showed significantly higher levels of arachidonic acid (AA) and AA-derived eicosanoids, PGA 2, TXB 2, and 11,12-EET, which are known to affect muscle and bone function. Moreover, Lipoxin B4, another AA product and an enhancer of bone turnover and negative regulator for muscle, showed significantly lower values in older mice compared to young mice in both genders. Furthermore, eicosapentaenoic acid and docosahexaenoic acid autoxidation products (20-HDoHE, 11-HDoHE, 7-HDoHE and 4-HDoHE), and omega-3 fatty acids that negatively regulate bone and muscle health, were significantly higher in older mice. In conclusion, these results suggest that LMs could play a role in modulating musculoskeletal function during aging.

An innovative electrochemical immuno-platform towards ultra-sensitive monitoring of 2-arachidonoyl glycerol in samples from rats with sleep deprivation: bioanalysis of endogenous cannabinoids using biosensor technology

The endocannabinoid system (ECS) is a complex of neurotransmitters in the central nervous system and plays a key role in regulating cognitive and physiological processes. 2-Arachidonoylglycerol (2-AG) is one of the imperative endocannabinoids that play key roles in the central nervous system. It acts as a signaling lipid and activates the cannabinoid CB1 receptor. In addition, 2-AG is involved in a variety of physiological functions such as energy balance, emotion, pain sensation, cognition, and neuroinflammation. So, rapid and specific diagnosis of 2-AG is of great importance in medical neuroscience. The development of new methods in this area has been one of the most important research areas in recent years. Herein, an innovative immunosensor is developed for quantification of 2-AG. For this means, gold nanostars (GNS) were synthesized and conjugated with a specific biotinylated antibody against 2-AG. The resultant bioconjugate, a bioreceptor with GNS, was immobilized on the surface of a gold electrode and used for the detection of the antigen based on the immunocomplex formation followed by analysis using different electrochemical techniques. For the first time, 2-AG protein was measured with an excellent linear range of 0.48–1 ng mL⁻¹ and lower limit of quantification of 0.48 ng L⁻¹ by the electroanalysis method. The engineered immunosensor showed high sensitivity and specificity in the presence of interfering antigens, proving its utility in neurological disorder detection. This immunosensor is the first sandwich type immunoassay for the detection of 2-AG in real samples and the first innovation of designing a novel sandwich type immunosensor for this analyte. Also, excellent analytical results are other advantages of this biosensor for the detection of 2-AG in human plasma samples and serum samples of rats under sleep deprivation. So, this is the first report of an immunosensor of 2-AG using a sandwich type immunosensor.

A novel electrochemical immunosensor based gold nanoparticles for the sensitive recognition of 2-AG was introduced.

Chronic Pain and the Endocannabinoid System: Smart Lipids - A Novel Therapeutic Option?

The development of a high-end cannabinoid-based therapy is the result of intense translational research, aiming to convert recent discoveries in the laboratory into better treatments for patients. Novel compounds and new regimes for drug treatment are emerging. Given that previously unreported signaling mechanisms for cannabinoids have been uncovered, clinical studies detailing their high therapeutic potential are mandatory. The advent of novel genomic, optogenetic, and viral tracing and imaging techniques will help to further detail therapeutically relevant functional and structural features. An evolutionarily highly conserved group of neuromodulatory lipids, their receptors, and anabolic and catabolic enzymes are involved in a remarkable variety of physiological and pathological processes and has been termed the endocannabinoid system (ECS). A large body of data has emerged in recent years, pointing to a crucial role of this system in the regulation of the behavioral domains of acquired fear, anxiety, and stress-coping. Besides neurons, also glia cells and components of the immune system can differentially fine-tune patterns of neuronal activity. Dysregulation of ECS signaling can lead to a lowering of stress resilience and increased incidence of psychiatric disorders. Chronic pain may be understood as a disease process evoked by fear-conditioned nociceptive input and appears as the dark side of neuronal plasticity. By taking a toll on every part of your life, this abnormal persistent memory of an aversive state can be more damaging than its initial experience. All strategies for the treatment of chronic pain conditions must consider stress-related comorbid conditions since cognitive factors such as beliefs, expectations, and prior experience (memory of pain) are key modulators of the perception of pain. The anxiolytic and anti-stress effects of medical cannabinoids can substantially modulate the efficacy and tolerability of therapeutic interventions and will help to pave the way to a successful multimodal therapy. Why some individuals are more susceptible to the effects of stress remains to be uncovered. The development of personalized prevention or treatment strategies for anxiety and depression related to chronic pain must also consider gender differences. An emotional basis of chronic pain opens a new horizon of opportunities for developing treatment strategies beyond the repeated sole use of acutely acting analgesics. A phase I trial to determine the pharmacokinetics, psychotropic effects, and safety profile of a novel nanoparticle-based cannabinoid spray for oromucosal delivery highlights a remarkable innovation in galenic technology and urges clinical studies further detailing the huge therapeutic potential of medical cannabis (Lorenzl et al.; this issue).

Cannabidiol and periodontal inflammatory disease: A critical assessment

Cannabidiol (CBD), a non-psychotropic cannabinoid produced by the genus Cannabis, is a phytoceutical that activates the endocannabinoid system (ECS) through binding to CB1 and CB2 receptors. The ECS is involved in cellular homeostasis and regulates metabolic processes in virtually all mammalian tissues. Published studies on CBD focus, inter alia, on its use in prophylaxis and as an anti-inflammatory agent. Here the authors present a critical assessment of the effects of CBD on inflammatory periodontal diseases caused by bacterial virulence factors, and evaluate critically the possible benefits and drawbacks of CBD use in dentistry. Particular attention is paid to the interaction of CBD with microbially colonized oral tissues, the inflammatory response in relation to the immune response, and the destruction/regeneration of hard and soft tissues of the periodontium.

Activity-Dependent Modulation of Tonic GABA Currents by Endocannabinoids in Hirudo verbana

Endocannabinoids are lipid neuromodulators that are synthesized on demand and primarily signal in a retrograde manner to elicit depression of excitatory and inhibitory synapses. Despite the considerable interest in their potential analgesic effects, there is evidence that endocannabinoids can have both pro-nociceptive and anti-nociceptive effects. The mechanisms contributing to the opposing effects of endocannabinoids in nociception need to be better understood before cannabinoid-based therapies can be effectively utilized to treat pain. Using the medicinal leech, Hirudo verbana, this work investigates whether endocannabinoids modulate tonic inhibition onto non-nociceptive afferents. In voltage clamp recordings, we analyzed changes in the tonic inhibition in pressure-sensitive (P) cells following pre-treatment with endocannabinoids, 2-arachidonoylglycerol (2-AG) or anandamide (AEA). We also tested whether high frequency stimulation (HFS) of nociceptive (N) cells could also modulate tonic inhibition. Both endocannabinoid application and N cell HFS depressed tonic inhibition in the P cell. Depression of tonic inhibition by N cell HFS was blocked by SB 366791 (a TRPV1 inhibitor). SB 366791 also prevented 2-AG-and AEA-induced depression of tonic inhibition. HFS-induced depression was not blocked by tetrahydrolipstatin (THL), which prevents 2-AG synthesis, nor AM 251 (a CB1 receptor inverse agonist). These results illustrate a novel activity-dependent modulation of tonic GABA currents that is mediated by endocannabinoid signaling and is likely to play an important role in sensitization of non-nociceptive afferent pathways.

New perspectives on the role of the neurosteroid pregnenolone as an endogenous regulator of type-1 cannabinoid receptor (CB1R) activity and function

Pregnenolone is a steroid with specific characteristics, being the first steroid to be synthesised from cholesterol at all sites of steroidogenesis, including the brain. For many years, pregnenolone was defined as an inactive precursor of all steroids because no specific target had been discovered. However, over the last decade, it has become a steroid of interest because it has been recognised as being a biomarker for brain-related disorders through the development of metabolomic approaches and advanced analytical methods. In addition, physiological roles for pregnenolone emerged when specific targets were discovered. In this review, we highlight the discovery of the selective interaction of pregnenolone with the type-1 cannabinoid receptor (CB1R). After describing the specific characteristic of CB1Rs, we discuss the newly discovered mechanisms of their regulation by pregnenolone. In particular, we describe the action of pregnenolone as a negative allosteric modulator and a specific signalling inhibitor of the CB1R. These particular characteristics of pregnenolone provide a great strategic opportunity for therapeutic development in CB1-related disorders. Finally, we outline new perspectives using innovative genetic tools for the discovery of original regulatory mechanisms of pregnenolone on CB1-related functions.

The cannabinoid receptor I (CB1) enhanced the osteogenic differentiation of BMSCs by rescue impaired mitochondrial metabolism function under inflammatory condition

Background

Periodontitis is a chronic infectious disease leading to bone resorption and periodontal tissue disruption under inflammatory stimulation. The osteogenic differentiation ability of mesenchymal stem cells (MSCs) is impaired under the inflammatory environment, which limits the effect of treatment. The cannabinoid receptor I (CB1) is the main effector of the endogenous cannabinoid system (ECS), and our previous study verified that CB1 could enhance the osteo/dentinogenic differentiation of dental MSCs, which might be a target for alveolar bone regeneration. However, the effect of CB1 on the osteogenic differentiation of MSCs derived from bone remains unknown. In present study, we investigated the role and mechanism of CB1 on mitochondrial function and osteogenic differentiation of human bone marrow mesenchymal stem cells (hBMSCs) under inflammatory environment.

Methods

Alkaline phosphatase (ALP) activity, alizarin red staining, quantitative calcium analysis, and osteogenic markers were used to detect the osteogenic differentiation ability of BMSCs. Real-time RT-PCR and Western blot were used to detect the gene expression. Seahorse Cell Mito Stress Test was used to detect the oxygen consumption rate (OCR). JC-10 assay was used to determine the mitochondrial membrane potential (MMP).

Results

CB1 increased osteogenic differentiation potential and mitochondrial energy metabolism, including the OCR, MMP, and enhanced the expressions of Nrf1 and Nrf2 in hBMSCs without or with TNF-α or INF-γ stimulation. Then, the inhibitor of mitochondrial electron transport chain (ETC), rotenone (ROT), inhibited the osteogenic differentiation in hBMSCs, and CB1 could rescue ROT impaired osteogenic differentiation potentials of hBMSCs without or with TNF-α or INF-γ stimulation. Activation of ETC by Coenzyme Q10 (CoQ10) could restore the impaired osteogenic differentiation of hBMSCs by depletion of CB1 without or with TNF-α or INF-γ stimulation. Mechanismly, CB1 could activate the JNK signaling pathway, p38 MAPK signaling pathway, and inhibit the Erk1/2 signaling pathway.

Conclusions

The activating of CB1 enhanced the osteogenic differentiation by rescuing the mitochondrial metabolism function in hBMSCs under the inflammatory environment, suggesting that CB1 is a potential target for enhancing bone regeneration under the inflammatory environment.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13287-022-02702-9.