Cannabidiol attenuates delayed-type hypersensitivity reactions via suppressing T-cell and macrophage reactivity

Immunomodulatory effects of Ulva-derived polysaccharides, oligosaccharides, and residues in a murine model of delayed-type hypersensitivity

Ulva, an edible green alga, contains sulfated polysaccharides and oligosaccharides that possess immunomodulatory and anti-inflammatory properties. The objective of this study was to investigate the anti-allergic effects of Ulva-derived samples of polysaccharides (UP), oligosaccharides (UO), and residues (UR) on delayed-type hypersensitivity (DTH) in mice. Oral treatment of mice with UP, UO, and UR (250 mg/kg body weight) daily noticeably improved the DTH reaction as evidenced by attenuation of footpad swelling and cell infiltration at the allergen-challenge site. Although the Ulva samples had limited impacts on the production of serum total IgG, decreased concentrations of allergen-specific IgG and IgG2a and an increased concentration of IgG1 were observed in the treated mice. Moreover, treatment with them suppressed allergen-induced IFN-γ and TNF-α secretion and elevated IL-4 secretion. However, none of the Ulva sample treatments could modulate the production of IL-10. Concordantly, the in situ data reveal that the Ulva sample treatments suppressed IFN-γ and TNF-α expression at the allergen-injection site. These findings collectively suggest the potential of UP, UO, and UR as functional food candidates for the management of delayed-type hypersensitivity.

Fufang Shengdi mixture alleviates psoriasis-like skin inflammation via promoting Annexin-A proteins expression

ETHNOPHARMACOLOGICAL RELEVANCE

Traditional Chinese medicine believes that "blood fever" is an important cause of psoriasis. Fufang Shengdi mixture (FFSD), based on the Hongban Decoction, is composed of Rehmannia glutinosa (Gaertn.) DC., Raw gypsum (Chinese: Sheng Shi Gao), and Lonicera japonica Thunb (Caprifoliaceae). FFSD has effects on nourishing Yin, clearing heat, connecting collaterals, and cooling blood. In modern medical explanation, FFSD has the effects of anti-inflammatory and immunosuppression. Our study proved that FFSD can suppress immunity and ameliorate the symptoms of imiquimod-induced psoriasis in mice.

AIM OF THE STUDY

This study evaluated the efficacy and possible mechanism of FFSD in psoriasis mice.

METHODS AND MATERIALS

First, the main components of FFSD were analyzed using high-performance liquid chromatography-tandem high-resolution mass spectrometry (HPLC-HRMS). An imiquimod (IMQ)-induced psoriasis mouse model was used to evaluate the efficacy of FFSD orally. Psoriasis area and severity index (PASI) scores were recorded throughout the course of the mice to reflect the severity of psoriasis. Hematoxylin-eosin staining was used to observe the pathological changes in skin lesions. Enzyme-linked immunosorbent assay (ELISA) was performed to test the level of IFN-γ and TNF-α in plasma. To further investigate the immunopharmacological effect of FFSD, we used chicken ovalbumin (OVA) to induce immunoreaction in mice. ELISA was used to detect the levels of anti-OVA antibody, IFN-γ and TNF-α in mice. Flow cytometry was performed to quantify the ratio of cell types in peripheral blood mononuclear cells (PBMCs) to evaluate the effect of FFSD on immunosuppression. Proteomics and bioinformatics analyzes were performed to find the regulation pathway of the immunosuppressive effect of FFSD. Finally, quantitative PCR (qPCR) and immunohistochemistry were used to measure the upregulation of Annexin-A proteins (ANXAs) in the skin lesion tissue of IMQ-induced mouse.

RESULTS

On the basis of knowing the composition of FFSD, we first proved the efficacy of FFSD in alleviating IMQ-induced psoriasis in mice. Second, we further clarified the pharmacological effect of FFSD on immunosuppression via OVA-induced mice. Subsequently, it was found that the significant up-regulation of ANXAs was caused by FFSD through proteomics analysis, and the finding was proved in the IMQ-induced psoriasis mouse model.

CONCLUSIONS

This study elucidates the immunosuppressive pharmacological effect of FFSD on improving psoriasis through up-regulating ANXAs.

A novel mechanism of cannabidiol in suppressing ovarian cancer through LAIR-1 mediated mitochondrial dysfunction and apoptosis

Cannabidiol (CBD) is a nonpsychoactive cannabinoid compound. It has been shown that CBD can inhibit the proliferation of ovarian cancer cells, but the underlying specific mechanism is unclear. We previously presented the first evidence for the expression of leukocyte-associated immunoglobulin-like receptor 1 (LAIR-1), a member of the immunosuppressive receptor family, in ovarian cancer cells. In the present study, we investigated the mechanism by which CBD inhibits the growth of SKOV3 and CAOV3 ovarian cancer cells, and we sought to understand the concurrent role of LAIR-1. In addition to inducing ovarian cancer cell cycle arrest and promoting cell apoptosis, CBD treatment significantly affected the expression of LAIR-1 and inhibited the PI3K/AKT/mTOR signaling axis and mitochondrial respiration in ovarian cancer cells. These changes were accompanied by an increase in ROS, loss of mitochondrial membrane potential, and suppression of mitochondrial respiration and aerobic glycolysis, thereby inducing abnormal or disturbed metabolism and reducing ATP production. A combined treatment with N-acetyl-l-cysteine and CBD indicated that a reduction in ROS production would restore PI3K/AKT/mTOR pathway signaling and ovarian cancer cell proliferation. We subsequently confirmed that the inhibitory effect of CBD on the PI3K/AKT/mTOR signal axis and mitochondrial bioenergy metabolism was attenuated by knockdown of LAIR-1. Our animal studies further support the in vivo anti-tumor activity of CBD and suggest its mechanism of action. In summary, the present findings confirm that CBD inhibits ovarian cancer cell growth by disrupting the LAIR-1-mediated interference with mitochondrial bioenergy metabolism and the PI3K/AKT/mTOR pathway. These results provide a new experimental basis for research into ovarian cancer treatment based on targeting LAIR-1 with CBD.

The NLRP3 Inflammasome in Stress Response: Another Target for the Promiscuous Cannabidiol

Many psychiatric patients do not respond to conventional therapy. There is a vast effort to investigate possible mechanisms involved in treatment resistance, trying to provide better treatment options, and several data points toward a possible involvement of inflammatory mechanisms. Microglia, glial, and resident immune cells are involved in complex responses in the brain, orchestrating homeostatic functions, such as synaptic pruning and maintaining neuronal activity. In contrast, microglia play a major role in neuroinflammation, neurodegeneration, and cell death. Increasing evidence implicate microglia dysfunction in neuropsychiatric disorders. The mechanisms are still unclear, but one pathway in microglia has received increased attention in the last 8 years, i.e., the NLRP3 inflammasome pathway. Stress response and inflammation, including microglia activation, can be attenuated by Cannabidiol (CBD). CBD has antidepressant, anti-stress, antipsychotic, anti-inflammatory, and other properties. CBD effects are mediated by direct or indirect modulation of many receptors, enzymes, and other targets. This review will highlight some findings for neuroinflammation and microglia involvement in stress-related psychiatric disorders, particularly addressing the NLRP3 inflammasome pathway. Moreover, we will discuss evidence and mechanisms for CBD effects in psychiatric disorders and animal models and address its potential effects on stress response via neuroinflammation and NLRP3 inflammasome modulation.

Cannabidiol on the Path from the Lab to the Cancer Patient: Opportunities and Challenges

Cannabidiol (CBD), a major non-psychotropic component of cannabis, is receiving growing attention as a potential anticancer agent. CBD suppresses the development of cancer in both in vitro (cancer cell culture) and in vivo (xenografts in immunodeficient mice) models. For critical evaluation of the advances of CBD on its path from laboratory research to practical application, in this review, we wish to call the attention of scientists and clinicians to the following issues: (a) the biological effects of CBD in cancer and healthy cells; (b) the anticancer effects of CBD in animal models and clinical case reports; (c) CBD’s interaction with conventional anticancer drugs; (d) CBD’s potential in palliative care for cancer patients; (e) CBD’s tolerability and reported side effects; (f) CBD delivery for anticancer treatment.

Cannabidiol-Driven Alterations to Inflammatory Protein Landscape of Lipopolysaccharide-Activated Macrophages In Vitro May Be Mediated by Autophagy and Oxidative Stress

Background: The nonpsychotropic phytocannabinoid cannabidiol (CBD) presents itself as a potentially safe and effective anti-inflammatory treatment relative to clinical standards. In this present study, we compare the capacity of CBD to the corticosteroid dexamethasone (Dex) in altering the secreted protein landscape of activated macrophages and speculate upon the mechanism underpinning these alterations. Materials and Methods: Human THP-1 monocytes were differentiated into macrophages (THP-1 derived macrophages [tMACs]), activated with lipopolysaccharide (LPS), and then treated with 5, 10, 25, 50, or 100 μM CBD or 10 μM Dex for 24 h. Following treatment, cytotoxicity of CBD and protein expression levels from culture supernatants and from whole cell lysates were assessed for secreted and intracellular proteins, respectively. Results: High concentration (50 and 100 μM) CBD treatments exhibit a cytotoxic effect on LPS-activated tMACs following the 24-h treatment. Relative to the LPS-activated and untreated control (M[LPS]), both 25 μM CBD and 10 μM Dex reduced expression of pro-inflammatory markers-tumor necrosis factor alpha, interleukin 1 beta, and regulated on activation, normal T cell expressed and secreted (RANTES)-as well as the pleiotropic marker interleukin-6 (IL-6). A similar trend was observed for anti-inflammatory markers interleukin-10 and vascular endothelial growth factor (VEGF). Dex further reduced secreted levels of monocyte chemoattractant protein-1 in addition to suppressing IL-6 and VEGF beyond treatments with CBD. The anti-inflammatory capacity of 25 μM CBD was concurrent with reduction in levels of phosphorylated mammalian target of rapamycin Ser 2448, endothelial nitric oxide synthase, and induction of cyclooxygenase 2 relative to M(LPS). This could suggest that the observed effects on macrophage immune profile may be conferred through inhibition of mammalian target of rapamycin complex 1 and ensuing induction of autophagy. Conclusion: Cumulatively, these data demonstrate cytotoxicity of high concentration CBD treatment. The data reported herein largely agree with other literature demonstrating the anti-inflammatory effects of CBD. However, there is discrepancy within literature surrounding efficacious concentrations and effects of CBD on specific secreted proteins. These data expand upon previous work investigating the effects of CBD on inflammatory protein expression in macrophages, as well as provide insight into the mechanism by which these effects are conferred.

Can Cannabidiol Affect the Efficacy of Chemotherapy and Epigenetic Treatments in Cancer?

The success of cannabinoids with chronic neuropathic pain and anxiety has been demonstrated in a multitude of studies. With the high availability of a non-intoxicating compound, cannabidiol (CBD), an over-the-counter medication, has generated heightened interest in its use in the field of oncology. This review focuses on the widespread therapeutic potential of CBD with regard to enhanced wound healing, lowered toxicity profiles of chemotherapeutics, and augmented antitumorigenic effects. The current literature is sparse with regard to determining the clinically relevant concentrations of CBD given the biphasic nature of the compound’s response. Therefore, there is an imminent need for further dose-finding studies in order to determine the optimal dose of CBD for both intermittent and regular users. We address the potential influence of regular or occasional CBD usage on therapeutic outcomes in ovarian cancer patients. Additionally, as the development of chemoresistance in ovarian cancer results in treatment failure, the potential for CBD to augment the efficacy of conventional chemotherapeutic and epigenetic drugs is a topic of significant importance. Our review is focused on the widespread therapeutic potential of CBD and whether or not a synergistic role exists in combination with epigenetic and classic chemotherapy medications.

Studies of involvement of G-protein coupled receptor-3 in cannabidiol effects on inflammatory responses of mouse primary astrocytes and microglia

Cannabidiol (CBD) exhibits anti-inflammatory and neuroprotective properties and is suggested to be effective in the pre-clinical and clinical treatment of illnesses of the central nervous system (CNS). Two major types of CNS glial cells, astrocytes and microglia, play critical roles in the development and pathogenesis of CNS diseases. However, the mechanisms by which CBD plays an anti-inflammatory and neuroprotective role for these glial cells have not been fully elucidated. In this study, we examined the effects of CBD on the inflammatory response of mouse primary astrocytes and microglia. We also investigated whether the effect of CBD on cytokine release is mediated by the G protein coupled receptor 3 (GPR3), which was recently identified as a novel receptor for CBD. Our results showed that CBD inhibited inflammatory responses of astrocytes and microglia stimulated with lipopolysaccharide (LPS), a Toll-like receptor 4 (TLR4) ligand in vitro and in vivo. In addition, CBD reduced the phosphorylation of STAT3 and NF-κB signaling pathways in LPS-stimulated astrocytes. However, the inhibitory effect of CBD on pro-inflammatory cytokine production was independent of GPR3 expression in both types of glial cells. Thus, although CBD is effective in ameliorating the activation of astrocytes and microglia, its mechanism of action still requires further study. Our data support the concept that CBD may have therapeutic potential for neurological disorders that involve neuroinflammation.

Repurposing Cannabidiol as a Potential Drug Candidate for Anti-Tumor Therapies

In recent years, evidence has accumulated that cannabinoids-especially the non-psychoactive compound, cannabidiol (CBD)-possess promising medical and pharmacological activities that might qualify them as potential anti-tumor drugs. This review is based on multiple studies summarizing different mechanisms for how CBD can target tumor cells including cannabinoid receptors or other constituents of the endocannabinoid system, and their complex activation of biological systems that results in the inhibition of tumor growth. CBD also participates in anti-inflammatory activities which are related to tumor progression, as demonstrated in preclinical models. Although the numbers of clinical trials and tested tumor entities are limited, there is clear evidence that CBD has anti-tumor efficacy and is well tolerated in human cancer patients. In summary, it appears that CBD has potential as a neoadjuvant and/or adjuvant drug in therapy for cancer.

A randomized, double-blind, placebo-controlled study of daily cannabidiol for the treatment of canine osteoarthritis pain

ABSTRACT

Over the last 2 decades, affirmative diagnoses of osteoarthritis (OA) in the United States have tripled due to increasing rates of obesity and an aging population. Hemp-derived cannabidiol (CBD) is the major nontetrahydrocannabinol component of cannabis and has been promoted as a potential treatment for a wide variety of disparate inflammatory conditions. Here, we evaluated CBD for its ability to modulate the production of proinflammatory cytokines in vitro and in murine models of induced inflammation and further validated the ability of a liposomal formulation to increase bioavailability in mice and in humans. Subsequently, the therapeutic potential of both naked and liposomally encapsulated CBD was explored in a 4-week, randomized placebo-controlled, double-blinded study in a spontaneous canine model of OA. In vitro and in mouse models, CBD significantly attenuated the production of proinflammatory cytokines IL-6 and TNF-α while elevating levels of anti-inflammatory IL-10. In the veterinary study, CBD significantly decreased pain and increased mobility in a dose-dependent fashion among animals with an affirmative diagnosis of OA. Liposomal CBD (20 mg/day) was as effective as the highest dose of nonliposomal CBD (50 mg/day) in improving clinical outcomes. Hematocrit, comprehensive metabolic profile, and clinical chemistry indicated no significant detrimental impact of CBD administration over the 4-week analysis period. This study supports the safety and therapeutic potential of hemp-derived CBD for relieving arthritic pain and suggests follow-up investigations in humans are warranted.

Immune Responses Regulated by Cannabidiol

Introduction: Cannabidiol (CBD) as Epidiolex^® (GW Pharmaceuticals) was recently approved by the U.S. Food and Drug Administration (FDA) to treat rare forms of epilepsy in patients 2 years of age and older. Together with the increased societal acceptance of recreational cannabis and CBD oil for putative medical use in many states, the exposure to CBD is increasing, even though all of its biological effects are not understood. Once such example is the ability of CBD to be anti-inflammatory and immune suppressive, so the purpose of this review is to summarize effects and mechanisms of CBD in the immune system. It includes a consideration of reports identifying receptors through which CBD acts, since the “CBD receptor,” if a single one exists, has not been definitively identified for the myriad immune system effects. The review then provides a summary of in vivo and in vitro effects in the immune system, in autoimmune models, with a focus on experimental autoimmune encephalomyelitis, and ends with identification of knowledge gaps.

Conclusion: Overall, the data overwhelmingly support the notion that CBD is immune suppressive and that the mechanisms involve direct suppression of activation of various immune cell types, induction of apoptosis, and promotion of regulatory cells, which, in turn, control other immune cell targets.

Cannabidiol-from Plant to Human Body: A Promising Bioactive Molecule with Multi-Target Effects in Cancer

Cannabis sativa L. is a plant long used for its textile fibers, seed oil, and oleoresin with medicinal and psychoactive properties. It is the main source of phytocannabinoids, with over 100 compounds detected so far. In recent years, a lot of attention has been given to the main phytochemicals present in Cannabis sativa L., namely, cannabidiol (CBD) and Δ9-tetrahydrocannabinol (THC). Compared to THC, CBD has non-psychoactive effects, an advantage for clinical applications of anti-tumor benefits. The review is designed to provide an update regarding the multi-target effects of CBD in different types of cancer. The main focus is on the latest in vitro and in vivo studies that present data regarding the anti-proliferative, pro-apoptotic, cytotoxic, anti-invasive, anti-antiangiogenic, anti-inflammatory, and immunomodulatory properties of CBD together with their mechanisms of action. The latest clinical evidence of the anticancer effects of CBD is also outlined. Moreover, the main aspects of the pharmacological and toxicological profiles are given.

DMH-CBD, a cannabidiol analog with reduced cytotoxicity, inhibits TNF production by targeting NF-kB activity dependent on A2A receptor

Cannabidiol (CBD) is a natural compound with psychoactive therapeutic properties well described. Conversely, the immunological effects of CBD are still poorly explored. In this study, the potential anti-inflammatory effects and underlying mechanisms of CBD and its analog Dimethyl-Heptyl-Cannabidiol (DMH-CBD) were investigated using RAW 264.7 macrophages. CBD and DMH-CBD suppressed LPS-induced TNF production and NF-kB activity in a concentration-dependent manner. Both compounds reduced the NF-kB activity in a μM concentration range: CBD (IC₅₀ = 15 μM) and DMH-CBD (IC₅₀ = 38 μM). However, the concentrations of CBD that mediated NF-kB inhibition were similar to those that cause cytotoxicity (LC₅₀ = 58 μM). Differently, DMH-CBD inhibited the NF-kB activation without cytotoxic effects at the same concentrations, although it provokes cytotoxicity at long-term exposure. The inhibitory action of the DMH-CBD on NF-kB activity was not related to the reduction in IkBα degradation or either p65 (NF-kB) translocation to the nucleus, although it decreased p38 MAP kinase phosphorylation. Additionally, 8-(3-Chlorostyryl) caffeine (CSC), an A_2A antagonist, reversed the effect of DMH-CBD on NF-kB activity in a concentration-dependent manner. Collectively, our results demonstrated that CBD reduces NF-kB activity at concentrations intimately associated with those that cause cell death, whereas DMH-CBD decreases NF-kB activity at non-toxic concentrations in an A_2A receptor dependent-manner.

Cannabidiol induced apoptosis in human monocytes through mitochondrial permeability transition pore-mediated ROS production

Cannabidiol (CBD) has been reported to induce apoptosis in immune cells through oxidative stress-related mechanisms. The objective of the present study was to investigate the cellular mechanisms for CBD-induced apoptosis and oxidative stress in human monocytes. Exposure of freshly isolated human monocytes to CBD induced apoptosis in a time- and concentration-dependent manner. Time-course analyses revealed the induction of intracellular reactive oxygen species (ROS) at 1-2 h post CBD (16 μM) exposure. By comparison, the CBD treatment rapidly elicited the depolarization of mitochondrial membrane potential (MMP) within 5 min, and the oxidation of cardiolipin, a major lipid component of the mitochondrial inner membrane, within 15 min. Moreover, CBD induced the release of cytochrome c (Cyt c) from mitochondria. Mechanistic studies revealed that CBD-induced ROS production and apoptosis were not associated with the alteration of mitochondrial superoxide dismutase activity, the electron leakage through mitochondrial respiratory chain, and Fe²⁺- and Ca²⁺-mediated mechanisms. In contrast, CBD-induced apoptosis and MMP depolarization were markedly attenuated by the mitochondrial permeability transition pore (MPTP) inhibitor cyclosporin A (CsA), but not the calcineurin inhibitor FK506. Furthermore, CsA prevented cardiolipin oxidation and the MPTP opening induced by CBD. The present study suggests that CBD acts on the mitochondria to elicit ROS generation and apoptosis through MPTP opening and provides critical insights into the cellular mechanisms for CBD-induced oxidative stress in apoptotic monocytes.

Cannabidiol: State of the art and new challenges for therapeutic applications

Over the past years, several lines of evidence support a therapeutic potential of Cannabis derivatives and in particular phytocannabinoids. Δ⁹-THC and cannabidiol (CBD) are the most abundant phytocannabinoids in Cannabis plants and therapeutic application for both compounds have been suggested. However, CBD is recently emerging as a therapeutic agent in numerous pathological conditions since devoid of the psychoactive side effects exhibited instead by Δ⁹-THC. In this review, we highlight the pharmacological activities of CBD, its cannabinoid receptor-dependent and -independent action, its biological effects focusing on immunomodulation, angiogenetic properties, and modulation of neuronal and cardiovascular function. Furthermore, the therapeutic potential of cannabidiol is also highlighted, in particular in nuerological diseases and cancer.

Anandamide attenuates Th-17 cell-mediated delayed-type hypersensitivity response by triggering IL-10 production and consequent microRNA induction

Endogenous cannabinoids [endocannabinoids] are lipid signaling molecules that have been shown to modulate immune functions. However, their role in the regulation of Th17 cells has not been studied previously. In the current study, we used methylated Bovine Serum Albumin [mBSA]-induced delayed type hypersensitivity [DTH] response in C57BL/6 mice, mediated by Th17 cells, as a model to test the anti-inflammatory effects of endocannabinoids. Administration of anandamide [AEA], a member of the endocannabinoid family, into mice resulted in significant mitigation of mBSA-induced inflammation, including foot pad swelling, cell infiltration, and cell proliferation in the draining lymph nodes [LN]. AEA treatment significantly reduced IL-17 and IFN-γ production, as well as decreased RORγt expression while causing significant induction of IL-10 in the draining LNs. IL-10 was critical for the AEA-induced mitigation of DTH response inasmuch as neutralization of IL-10 reversed the effects of AEA. We next analyzed miRNA from the LN cells and found that 100 out of 609 miRNA species were differentially regulated in AEA-treated mice when compared to controls. Several of these miRNAs targeted proinflammatory mediators. Interestingly, many of these miRNA were also upregulated upon in vitro treatment of LN cells with IL-10. Together, the current study demonstrates that AEA may suppress Th-17 cell–mediated DTH response by inducing IL-10 which in turn triggers miRNA that target proinflammatory pathways.

Bioactive lipid mediators in skin inflammation and immunity

The skin is the primary barrier from the outside environment, protecting the host from injury, infectious pathogens, water loss and solar ultraviolet radiation. In this role, it is supported by a highly organized system comprising elements of innate and adaptive immunity, responsive to inflammatory stimuli. The cutaneous immune system is regulated by mediators such as cytokines and bioactive lipids that can initiate rapid immune responses with controlled inflammation, followed by efficient resolution. However, when immune responses are inadequate or mounted against non-infectious agents, these mediators contribute to skin pathologies involving unresolved or chronic inflammation. Skin is characterized by active lipid metabolism and fatty acids play crucial roles both in terms of structural integrity and functionality, in particular when transformed to bioactive mediators. Eicosanoids, endocannabinoids and sphingolipids are such key bioactive lipids, intimately involved in skin biology, inflammation and immunity. We discuss their origins, role and influence over various cells of the epidermis, dermis and cutaneous immune system and examine their function in examples of inflammatory skin conditions. We focus on psoriasis, atopic and contact dermatitis, acne vulgaris, wound healing and photodermatology that demonstrate dysregulation of bioactive lipid metabolism and examine ways of using this insight to inform novel therapeutics.

The non-psychoactive plant cannabinoid, cannabidiol affects cholesterol metabolism-related genes in microglial cells

Cannabidiol (CBD) is a non-psychoactive plant cannabinoid that is clinically used in a 1:1 mixture with the psychoactive cannabinoid Δ(9)-tetrahydrocannabinol (THC) for the treatment of neuropathic pain and spasticity in multiple sclerosis. Our group previously reported that CBD exerts anti-inflammatory effects on microglial cells. In addition, we found that CBD treatment increases the accumulation of the endocannabinoid N-arachidonoyl ethanolamine (AEA), thus enhancing endocannabinoid signaling. Here we proceeded to investigate the effects of CBD on the modulation of lipid-related genes in microglial cells. Cell viability was tested using FACS analysis, AEA levels were measured using LC/MS/MS, gene array analysis was validated with real-time qPCR, and cytokine release was measured using ELISA. We report that CBD significantly upregulated the mRNAs of the enzymes sterol-O-acyl transferase (Soat2), which synthesizes cholesteryl esters, and of sterol 27-hydroxylase (Cyp27a1). In addition, CBD increased the mRNA of the lipid droplet-associated protein, perilipin2 (Plin2). Moreover, we found that pretreatment of the cells with the cholesterol chelating agent, methyl-β-cyclodextrin (MBCD), reversed the CBD-induced increase in Soat2 mRNA but not in Plin2 mRNA. Incubation with AEA increased the level of Plin2, but not of Soat2 mRNA. Furthermore, MBCD treatment did not affect the reduction by CBD of the LPS-induced release of the proinflammatory cytokine IL-1β. CBD treatment modulates cholesterol homeostasis in microglial cells, and pretreatment with MBCD reverses this effect without interfering with CBD's anti-inflammatory effects. The effects of the CBD-induced increase in AEA accumulation on lipid-gene expression are discussed.