Rimonabant inhibits TNF-α-induced endothelial IL-6 secretion via CB1 receptor and cAMP-dependent protein kinase pathway

Renal Outcomes and Other Adverse Effects of Cannabinoid Supplementation

This narrative review explores the benefits and risks of cannabinoids in kidney health, particularly in individuals with pre-existing renal conditions. It discusses the roles of cannabinoid receptor ligands (phytocannabinoids, synthetic cannabinoids, and endocannabinoids) in kidney physiology. The metabolism and excretion of these substances are also highlighted, with partial elimination occurring via the kidneys. The effects of cannabinoids on kidney function are examined, emphasizing both their potential to offer nephroprotection and the risks they may pose, such as cannabinoid hyperemesis syndrome and ischemia-reperfusion injury. These complexities underscore the intricate interactions between cannabinoids and renal health. Furthermore, this review highlights the association between chronic synthetic cannabinoid use and acute kidney injury, stressing the need for further research into their mechanisms and risks. This article also highlights the growing prevalence of edible cannabis and hemp seed consumption, emphasizing their nutritional benefits, legal regulations, and challenges such as inconsistent labeling, potential health risks, and implications for kidney health. The review delves into the roles of CB1 and CB2 receptors in diabetic nephropathy, chronic kidney disease, and obesity-related kidney dysfunction, discussing the therapeutic potential of CB2 agonists and CB1 antagonists. Additionally, it examines the potential diuretic and anti-inflammatory effects of cannabinoids in preventing kidney stones, suggesting that cannabinoids could reduce crystal retention and lower the risk of stone formation. Cannabinoids' effects on kidneys depend heavily on the characteristics of individual substances, as synthetic cannabinoids pose a major threat to the health of users. Cannabinoids offer therapeutic potential but require more research to confirm their benefits. Distinguishing between therapeutic cannabinoids and harmful synthetic variants is crucial for safe clinical application.

Potential Implications of Rimonabant on Age-Related Oxidative Stress and Inflammation

Over the last decades, growing interest has turned to preventive and therapeutic approaches for achieving successful aging. Oxidative stress and inflammation are fundamental features of cardiovascular diseases; therefore, potential targets of them can improve cardiac outcomes. Our study aimed to examine the involvement of the endocannabinoid system, especially the CB1 receptor blockade, on inflammatory and oxidant/antioxidant processes. Twenty-month-old female and male Wistar rats were divided into rimonabant-treated and aging control (untreated) groups. Rimonabant, a selective CB1 receptor antagonist, was administered at the dose of 1 mg/kg/day intraperitoneally for 2 weeks. Cardiac amounts of ROS, the antioxidant glutathione and superoxide dismutase (SOD), and the activity and concentration of the heme oxygenase (HO) enzyme were detected. Among inflammatory parameters, nuclear factor-kappa B (NF-κB), tumor necrosis factor-alpha (TNF-α), and myeloperoxidase (MPO) enzyme activity were measured. Two weeks of low dose rimonabant treatment significantly reduced the cardiac ROS via boosting of the antioxidant defense mechanisms as regards the HO system, and the SOD and glutathione content. Consistently, the age-related inflammatory response was alleviated. Rimonabant-treated animals showed significantly decreased NF-κB, TNF-α, and MPO levels. Our findings prove the beneficial involvement of CB1 receptor blocker rimonabant on inflammatory and oxidative damages to the aging heart.

The fundamental role of the endocannabinoid system in endometrium and placenta: implications in pathophysiological aspects of uterine and pregnancy disorders

BACKGROUND

The endocannabinoid system (ECS) consists of the cannabinoid receptors CB1 and CB2, the main endocannabinoids anandamide (AEA) and 2-arachidonoylglycerol (2-AG) and their metabolic enzymes N-acylphosphatidylethanolamine-specific phospholipase D, fatty acid amide hydrolase, diacylglycerol lipase and monoacylglycerol lipase. This system is involved in the modulation of essential physiological processes. Its role in the reproductive system has become significantly important in recent years, given its major role in events such as gametogenesis, decidualisation, implantation and placentation.

OBJECTIVE AND RATIONALE

In this paper, we review the literature and summarize the role of the ECS elements in reproduction and their potential as early markers for diagnosis of reproductive disorders or as pharmacological targets for treatment.

SEARCH METHODS

Original research and review papers published from 1964 to June 2019 were selected in terms of relevance, reliability and quality by searching PubMed, MEDLINE and Web of Science, using the following search terms: endocannabinoid system and endometriosis; endocannabinoid system and ectopic pregnancy; endocannabinoid system and miscarriage; endocannabinoid system and pre-eclampsia; endocannabinoid system and endometrial cancer; endocannabinoid system and reproduction; endocannabinoid, endometrium; placenta; N-acylethanolamines; anandamide; 2-arachidonoylglycerol; and cannabinoids.

OUTCOMES

This review demonstrates relevant information concerning ECS alterations in endometriosis, ectopic pregnancy, miscarriage, pre-eclampsia and endometrial cancer. We highlight the importance of the endocannabinoids in endometrial and placental physiology and pathophysiology, from studies in vitro and in vivo and in clinical observations. The most studied of the endogenous cannabinoids is AEA. The levels of AEA were increased in plasma of patients with endometriosis and miscarriage, as well as in the fallopian tube of women with ectopic pregnancy and in endometrial biopsies of endometrial cancer. Changes in the pattern of expression of the cannabinoid receptor CB1 were also observed in endometrial biopsies of endometriosis, fallopian tube and decidua of patients with ectopic pregnancy and pre-eclamptic placenta. Moreover, alterations in CB2 expression have been reported in association with endometrial cancer. In general, studies on the cannabinoid signalling through CB2 and on the biological activities of the other major endocannabinoid, namely 2-AG, as well as its metabolic enzymes are scarce and avidly required.

WIDER IMPLICATIONS

The pathophysiological mechanisms involved in the described endometrial and placental pathologies are still unclear and lack the means for an early diagnosis. Based on current evidence, though alterations in ECS are demonstrated at tissue level, it is difficult to associate plasmatic changes in AEA with specific endometrial and placental diseases. Thus, pairing alterations in AEA levels with 2-AG and/or other endocannabinoid-like molecules may provide more accurate and early diagnoses. In addition, patients may benefit from new therapies that target the ECS and endocannabinoid signalling.

Age-dependent Alteration in Mitochondrial Dynamics and Autophagy in Hippocampal Neuron of Cannabinoid CB1 Receptor-deficient Mice

Endocannabinoid system activity contributes to the homeostatic defense against aging and thus may counteract the progression of brain aging. The cannabinoid type 1 (CB1) receptor activity declines with aging in the brain, which impairs neuronal network integrity and cognitive functions. However, the underlying mechanisms that link CB1 activity and memory decline remain unknown. Mitochondrial activity profoundly influences neuronal function, and age-dependent mitochondrial activity change is one of the known hallmarks of brain aging. As CB1 receptor is expressed on mitochondria and may regulate neuronal energy metabolism in hippocampus, we hypothesized that CB1 receptors might influence mitochondria in hippocampal neurons. Here, we found that CB1 receptor significantly affected mitochondrial autophagy (mitophagy) and morphology in an age-dependent manner. Serine 65-phosphorylated ubiquitin, a key marker for mitophagy, was reduced in adult CB1-deficient mice (CB1-KO) compared to those in wild type controls, particularly in CA1 pyramidal cell layer. Transmission electron microscopy (TEM) analysis showed reduced mitophagy-like events in hippocampus of adult CB1-KO. TEM analysis also showed that mitochondrial morphology in adult CB1-KO mice was altered shown by an increase in thin and elongated mitochondria in hippocampal neurons. 3D reconstruction of mitochondrial morphology after scanning electron microscopy additionally revealed an enhanced density of interconnected mitochondria. Altogether, these findings suggest that reduced CB1 signaling in CB1-KO mice leads to reduced mitophagy and abnormal mitochondrial morphology in hippocampal neurons during aging. These mitochondrial changes might be due to the impairments in mitochondrial quality control system, which links age-related decline in CB1 activity and impaired memory.

2-(5-(4-Chlorophenyl)-1-(2,4-dichlorophenyl)-4-methyl-1H-pyrazol-3-yl)-N-(2-hydroxyethyl)-2-oxoacetamide (CDMPO) has anti-inflammatory properties in microglial cells and prevents neuronal and behavioral deficits in MPTP mouse model of Parkinson's disease

Parkinson's disease (PD) is characterized by the selective loss of nigrostriatal dopamine neurons associated with microglial activation. Inhibition of the inflammatory response elicited by activated microglia could be an effective strategy to alleviate the progression of PD. Here, we synthesized 2-(5-(4-chlorophenyl)-1-(2,4-dichlorophenyl)-4-methyl-1H-pyrazol-3-yl)-N-(2-hydroxyethyl)-2-oxoacetamide (CDMPO) and studied its protective anti-inflammatory mechanisms following lipopolysaccharide (LPS)-induced neuroinflammation in vitro and 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced neurotoxicity in vivo. CDMPO and its parent compound, rimonabant, significantly attenuated nitric oxide (NO) production in LPS-stimulated primary microglia and BV2 cells. Furthermore, CDMPO significantly inhibited the release of proinflammatory cytokines and prostaglandin E2 (PGE₂) by activated BV2 cells, also suppressed expression of inducible nitric oxide synthase (iNOS), and cyclooxygenase-2 (COX-2). Mechanistically, CDMPO attenuated LPS-induced activation of nuclear factor-kappa B (NF-κB), inhibitor of kappa B alpha (IκBα), and p38 phosphorylation in BV2 cells. MPTP intoxication of mice results in glial activation, tyrosine hydroxylase (TH) depletion, and significant behavioral deficits. Prophylactic treatment with CDMPO decreased proinflammatory molecules via NF-κB and p38 mitogen-activated protein kinase signaling, resulting in protection of dopaminergic neurons and improved behavioral impairments. These results suggest that CDMPO is a promising neuroprotective agent for the prevention and treatment of microglia-mediated neuroinflammatory conditions and may be useful for behavioral improvement in PD phenotype.

The endocannabinoid system: 'NO' longer anonymous in the control of nitrergic signalling?

The endocannabinoid system (ECS) is a key cellular signalling system that has been implicated in the regulation of diverse cellular functions. Importantly, growing evidence suggests that the biological actions of the ECS may, in part, be mediated through its ability to regulate the production and/or release of nitric oxide, a ubiquitous bioactive molecule, which functions as a versatile signalling intermediate. Herein, we review and discuss evidence pertaining to ECS-mediated regulation of nitric oxide production, as well as the involvement of reactive nitrogen species in regulating ECS-induced signal transduction by highlighting emerging work supporting nitrergic modulation of ECS function. Importantly, the studies outlined reveal that interactions between the ECS and nitrergic signalling systems can be both stimulatory and inhibitory in nature, depending on cellular context. Moreover, such crosstalk may act to maintain proper cell function, whereas abnormalities in either system can undermine cellular homoeostasis and contribute to various pathologies associated with their dysregulation. Consequently, future studies targeting these signalling systems may provide new insights into the potential role of the ECS–nitric oxide signalling axis in disease development and/or lead to the identification of novel therapeutic targets for the treatment of nitrosative stress-related neurological, cardiovascular, and metabolic disorders.

Modulation of cellular redox homeostasis by the endocannabinoid system

The endocannabinoid system (ECS) and reactive oxygen species (ROS) constitute two key cellular signalling systems that participate in the modulation of diverse cellular functions. Importantly, growing evidence suggests that cross-talk between these two prominent signalling systems acts to modulate functionality of the ECS as well as redox homeostasis in different cell types. Herein, we review and discuss evidence pertaining to ECS-induced regulation of ROS generating and scavenging mechanisms, as well as highlighting emerging work that supports redox modulation of ECS function. Functionally, the studies outlined reveal that interactions between the ECS and ROS signalling systems can be both stimulatory and inhibitory in nature, depending on cell stimulus, the source of ROS species and cell context. Importantly, such cross-talk may act to maintain cell function, whereas abnormalities in either system may propagate and undermine the stability of both systems, thereby contributing to various pathologies associated with their dysregulation.

Mitochondria: a possible nexus for the regulation of energy homeostasis by the endocannabinoid system?

The endocannabinoid system (ECS) regulates numerous cellular and physiological processes through the activation of receptors targeted by endogenously produced ligands called endocannabinoids. Importantly, this signaling system is known to play an important role in modulating energy balance and glucose homeostasis. For example, current evidence indicates that the ECS becomes overactive during obesity whereby its central and peripheral stimulation drives metabolic processes that mimic the metabolic syndrome. Herein, we examine the role of the ECS in modulating the function of mitochondria, which play a pivotal role in maintaining cellular and systemic energy homeostasis, in large part due to their ability to tightly coordinate glucose and lipid utilization. Because of this, mitochondrial dysfunction is often associated with peripheral insulin resistance and glucose intolerance as well as the manifestation of excess lipid accumulation in the obese state. This review aims to highlight the different ways through which the ECS may impact upon mitochondrial abundance and/or oxidative capacity and, where possible, relate these findings to obesity-induced perturbations in metabolic function. Furthermore, we explore the potential implications of these findings in terms of the pathogenesis of metabolic disorders and how these may be used to strategically develop therapies targeting the ECS.

The endocannabinoid/endovanilloid N-arachidonoyl dopamine (NADA) and synthetic cannabinoid WIN55,212-2 abate the inflammatory activation of human endothelial cells

Although cannabinoids, such as Δ(9)-tetrahydrocannabinol, have been studied extensively for their psychoactive effects, it has become apparent that certain cannabinoids possess immunomodulatory activity. Endothelial cells (ECs) are centrally involved in the pathogenesis of organ injury in acute inflammatory disorders, such as sepsis, because they express cytokines and chemokines, which facilitate the trafficking of leukocytes to organs, and they modulate vascular barrier function. In this study, we find that primary human ECs from multiple organs express the cannabinoid receptors CB1R, GPR18, and GPR55, as well as the ion channel transient receptor potential cation channel vanilloid type 1. In contrast to leukocytes, CB2R is only minimally expressed in some EC populations. Furthermore, we show that ECs express all of the known endocannabinoid (eCB) metabolic enzymes. Examining a panel of cannabinoids, we demonstrate that the synthetic cannabinoid WIN55,212-2 and the eCB N-arachidonoyl dopamine (NADA), but neither anandamide nor 2-arachidonoylglycerol, reduce EC inflammatory responses induced by bacterial lipopeptide, LPS, and TNFα. We find that endothelial CB1R/CB2R are necessary for the effects of NADA, but not those of WIN55,212-2. Furthermore, transient receptor potential cation channel vanilloid type 1 appears to counter the anti-inflammatory properties of WIN55,212-2 and NADA, but conversely, in the absence of these cannabinoids, its inhibition exacerbates the inflammatory response in ECs activated with LPS. These data indicate that the eCB system can modulate inflammatory activation of the endothelium and may have important implications for a variety of acute inflammatory disorders that are characterized by EC activation.

Differential migratory properties of monocytes isolated from human subjects naïve and non-naïve to Cannabis

This study evaluates the migratory potential of monocytes isolated from two groups of human subjects: naïve and non-naïve to Cannabis. Phytocannabinoids (pCB), the bioactive agents produced by the plant Cannabis, regulate the phenotype and function of immune cells by interacting with CB1 and CB2 receptors. It has been shown that agents influencing the phenotype of circulating monocytes influence the phenotype of macrophages and the outcome of immune responses. To date, nothing is known about the acute and long-term effects of pCB on human circulating monocytes. Healthy subjects were recruited for a single blood draw. Monocytes were isolated, fluorescently labeled and their migration quantified using a validated assay that employs near infrared fluorescence and modified Boyden chambers. CB1 and CB2 receptor mRNA expression was quantified by qPCR. Monocytes from all subjects (n = 10) responded to chemokine (c-c motif) ligand 2 (CCL2) and human serum stimuli. Acute application of pCB significantly inhibited both the basal and CCL2-stimulated migration of monocytes, but only in subjects non-naïve to Cannabis. qPCR analysis indicates that monocytes from subjects non-naïve to Cannabis express significantly more CB1 mRNA. The phenotype of monocytes isolated from subjects non-naïve to Cannabis is significantly different from monocytes isolated from subjects naïve to Cannabis. Only monocytes from subjects non-naïve to Cannabis respond to acute exposure to pCB by reducing their overall migratory capacity. Our study suggests that chronic exposure to Cannabis affects the phenotype of circulating monocytes and accordingly could influence outcome of inflammatory responses occurring in injured tissues.

Rimonabant, a cannabinoid receptor type 1 inverse agonist, inhibits hepatocyte lipogenesis by activating liver kinase B1 and AMP-activated protein kinase axis downstream of Gα i/o inhibition

Liver X receptor-α (LXRα) and its target sterol regulatory element-binding protein-1c (SREBP-1c) play key roles in hepatic lipogenesis. Rimonabant, an inverse agonist of cannabinoid receptor type 1 (CB1), has been studied as an antiobesity drug. In view of the link between CB1 and energy metabolism, this study investigated the effect of rimonabant on LXRα-mediated lipogenesis in hepatocytes and the underlying basis. Rimonabant treatment inhibited CYP7A1-LXRα response element gene transactivation and an increase in LXRα mRNA level by the LXRα agonist N-(2,2,2-trifluoroethyl)-N-[4-[2,2,2-trifluoro-1-hydroxy-1-(trifluoromethyl)ethyl]phenyl]-benzenesulfonamide (T0901317) in HepG2 cells. Rimonabant consistently attenuated the activation of SREBP-1c and its target gene induction. The reversal by CB1 agonists on rimonabant's repression of SREBP-1c supported the role of CB1 in this effect. Rimonabant inhibited the activation of SREBP-1c presumably via Gα(i/o) inhibition, as did pertussis toxin. Adenylyl cyclase activator forskolin or 8-bromo-cAMP treatment mimicked the action of rimonabant, suggesting that Gα(i/o) inhibition causes repression of SREBP-1c by increasing the cAMP level. Knockdown or chemical inhibition of protein kinase A (PKA) prevented the inhibition of LXRα by rimonabant, supporting the fact that an increase in cAMP content and PKA activation, which catalyzes LXRα inhibitory phosphorylation, might be responsible for the antilipogenic effect. In addition, rimonabant activated liver kinase B1 (LKB1), resulting in the activation of AMP-activated protein kinase responsible for LXRα repression. Moreover, PKA inhibition prevented the activation of LKB1, supporting the fact that PKA regulates LKB1. In conclusion, rimonabant has an antilipogenic effect in hepatocytes by inhibiting LXRα-dependent SREBP-1c induction, as mediated by an increase in PKA activity and PKA-mediated LKB1 activation downstream of CB1-coupled Gα(i/o) inhibition.