In Vitro Studies on Therapeutic Effects of Cannabidiol in Neural Cells: Neurons, Glia, and Neural Stem Cells

Impact of cannabidiol on brain glucose metabolism of C57Bl/6 male mice previously exposed to cocaine

Despite evidence of the beneficial effects of cannabidiol (CBD) in animal models of cocaine use disorder (CUD), CBD neuronal mechanisms remain poorly understood. This study investigated the effects of CBD treatment on brain glucose metabolism, in a CUD animal model, using [18F]FDG positron emission tomography (PET). Male C57Bl/6 mice were injected with cocaine (20 mg/kg, i.p.) every other day for 9 days, followed by 8 days of CBD administration (30 mg/kg, i.p.). After 48 h, animals were challenged with cocaine. Control animals received saline/vehicle. [18F]FDG PET was performed at four time points: baseline, last day of sensitization, last day of withdrawal/CBD treatment, and challenge. Subsequently, the animals were euthanized and immunohistochemistry was performed on the hippocampus and amygdala to assess the CB1 receptors, neuronal nuclear protein, microglia (Iba1), and astrocytes (GFAP). Results showed that cocaine administration increased [18F]FDG uptake following sensitization. CBD treatment also increased [18F]FDG uptake in both saline and cocaine groups. However, animals that were sensitized and challenged with cocaine, and those receiving only an acute cocaine injection during the challenge phase, did not exhibit increased [18F]FDG uptake when treated with CBD. Furthermore, CBD induced modifications in the integrated density of NeuN, Iba, GFAP, and CB1R in the hippocampus and amygdala. This is the first study addressing the impact of CBD on brain glucose metabolism in a preclinical model of CUD using PET. Our findings suggest that CBD disrupts cocaine-induced changes in brain energy consumption and activity, which might be correlated with alterations in neuronal and glial function.

High Concentrations of Cannabidiol Induce Neurotoxicity in Neurosphere Culture System

Recent studies have demonstrated that cannabinoids are potentially effective in the treatment of various neurological conditions, and cannabidiol (CBD), one of the most studied compounds, has been proposed as a non-toxic option. However, the adverse effects of CBD on neurodevelopmental processes have rarely been studied in cell culture systems. To better understand CBD's influence on neurodevelopment, we exposed neural progenitor cells (NPCs) to different concentrations of CBD (1 µM, 5 µM, and 10 µM). We assessed the morphology, migration, differentiation, cell death, and gene expression in 2D and 3D bioprinted models to stimulate physiological conditions more effectively. Our results showed that CBD was more toxic at higher concentrations (5 µM and 10 µM) and affected the viability of NPCs than at lower concentrations (1 µM), in both 2D and 3D models. Moreover, our study revealed that higher concentrations of CBD drastically reduced the size of neurospheres and the number of NPCs within neurospheres, impaired the morphology and mobility of neurons and astrocytes after differentiation, and reduced neurite sprouting. Interestingly, we also found that CBD alters cellular metabolism by influencing the expression of glycolytic and β-oxidative enzymes in the early and late stages of metabolic pathways. Therefore, our study demonstrated that higher concentrations of CBD promote important changes in cellular functions that are crucial during CNS development.

Effect of Cannabidiol in LPS-Induced Toxicity in Astrocytes: Possible Role for Cannabinoid Type-1 Receptors

Cerebral metabolic abnormalities are common in neurodegenerative diseases. Previous studies have shown that mitochondrial damage alters ATP production and increases reactive oxygen species (ROS) release which may contribute to neurodegeneration. In the present study, we investigated the neuroprotective effects of cannabidiol (CBD), a non-psychoactive component derived from marijuana (Cannabis sativa L.), on astrocytic bioenergetic balance in a primary cell culture model of lipopolysaccharide (LPS)-induced neurotoxicity. Astrocytic metabolic profiling using an extracellular flux analyzer demonstrated that CBD decreases mitochondrial proton leak, increased spare respiratory capacity and coupling efficiency in LPS-stimulated astrocytes. Simultaneously, CBD increased astrocytic glycolytic capacity and glycolysis reserve in a cannabinoid receptor type 1 (CB1)-dependent manner. CBD-restored metabolic changes were correlated with a significant decrease in the pro-inflammatory cytokines tumor necrosis factor α (TNFα) and interleukin-6 (IL-6) concentration and reduction of ROS production in LPS-stimulated astrocytes. These results suggest that CBD may inhibit LPS-induced metabolic impairments and inflammation by enhancing astrocytic metabolic glycolysis versus oxidative phosphorylation through its action on CB1 receptors. The present findings suggest CBD as a potential anti-inflammatory treatment in metabolic pathologies and highlight a possible role for the cannabinoidergic system in the modulation of mitochondrial oxidative stress. CBD enhances mitochondrial bioenergetic profile, attenuates proinflammatory cytokines release, and ROS overproduction of astrocytes stimulated by LPS. These effects are not mediated directly by CB1 receptors, while these receptors seem to have a key role in the anti-inflammatory response of the endocannabinoid system on astrocytes, as their specific inhibition by SR141716A led to increased pro-inflammatory cytokines release and ROS production. The graphical abstract is created with BioRender.com.

Neutralization of Cannabidiol Neurotoxicity in Neuron-Astrocyte Sandwich Coculture

Cannabidiol (CBD), a main nonpsychoactive phytocannabinoid in the Cannabis genus, has been in the limelight for its potential health benefits in various neurological diseases. However, the safety issue of CBD in the nervous system has not been settled fully, while CBD has been reported to have mild side effects including dizziness and somnolence. In this work, a platform of neuron-astrocyte sandwich coculture to investigate the neurotoxicity of CBD, as well as the neuronal responses to CBD, in a more in vivo relevant mode is constructed. CBD (15 and 30 µm) causes the viability decrease, along with morphological damage, in the neuron-alone culture, whereas its neurotoxic effects are significantly attenuated by the supports of astrocytes in the neuron-astrocyte coculture. In addition, it is found that CBD-induced increase of intracellular Ca2+ concentration and depolarization of mitochondrial membrane potential, via activation of transient receptor potential vanilloid 1, are noticeably ameliorated by coculturing neurons with astrocytes. This work provides crucial information in the development of CBD as therapeutics for neurological disorders, as well as in a fundamental understanding of how CBD works in the nervous system.

Anti-oxidant effects of cannabidiol relevant to intracerebral hemorrhage

Intracerebral hemorrhage (ICH) is a subtype of stroke with a high mortality rate. Oxidative stress cascades play an important role in brain injury after ICH. Cannabidiol, a major non-psychotropic phytocannabinoids, has drawn increasing interest in recent years as a potential therapeutic intervention for various neuropsychiatric disorders. Here we provide a comprehensive review of the potential therapeutic effects of cannabidiol in countering oxidative stress resulting from ICH. The review elaborates on the various sources of oxidative stress post-ICH, including mitochondrial dysfunction, excitotoxicity, iron toxicity, inflammation, and also highlights cannabidiol's ability to inhibit ROS/RNS generation from these sources. The article also delves into cannabidiol's role in promoting ROS/RNS scavenging through the Nrf2/ARE pathway, detailing both extranuclear and intranuclear regulatory mechanisms. Overall, the review underscores cannabidiol's promising antioxidant effects in the context of ICH and suggests its potential as a therapeutic option.

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.

Cannabidiol-Loaded Nanocarriers and Their Therapeutic Applications

Cannabidiol (CBD), one of the most promising constituents isolated from Cannabis sativa, exhibits diverse pharmacological actions. However, the applications of CBD are restricted mainly due to its poor oral bioavailability. Therefore, researchers are focusing on the development of novel strategies for the effective delivery of CBD with improved oral bioavailability. In this context, researchers have designed nanocarriers to overcome limitations associated with CBD. The CBD-loaded nanocarriers assist in improving the therapeutic efficacy, targetability, and controlled biodistribution of CBD with negligible toxicity for treating various disease conditions. In this review, we have summarized and discussed various molecular targets, targeting mechanisms and types of nanocarrier-based delivery systems associated with CBD for the effective management of various disease conditions. This strategic information will help researchers in the establishment of novel nanotechnology interventions for targeting CBD.

Effects of Cannabidiol on Locomotor Activity

Cannabidiol (CBD) is the second cannabinoid, in order of importance after Δ9-tetrahydrocannabinol (THC), from Cannabis sativa. Unlike THC, CBD does not cause psychotomimetic effects, and although these compounds have the same chemical formula, their pharmacological characteristics are not equivalent. Preclinical studies suggest that CBD has anti-inflammatory, analgesic, anxiolytic, antiemetic, anticonvulsant, and antipsychotic properties and influences the sleep–wake cycle. The evaluation of effects on spontaneous motor activity is crucial in experimental pharmacology, and the careful measurement of laboratory animal movement is an established method to recognize the effects of stimulant and depressant drugs. The potential influence of CBD on locomotor activity has been investigated through numerous in vivo experiments. However, there is no clear picture of the impact of CBD on these issues, even though it is administered alone for medical uses and sold with THC as a drug for pain caused by muscle spasms in multiple sclerosis, and it was recently licensed as a drug for severe forms of infantile epilepsy. On this basis, with the aim of developing deeper knowledge of this issue, scientific data on CBD’s influence on locomotor activity are discussed here. We conducted research using PubMed, Scopus, Google Scholar, and a search engine for literature between January 2009 and December 2021 on life sciences and biomedical topics using the keywords “motor activity”, “locomotor activity”, and “locomotion” in combination with “cannabidiol”. In this article, we discuss findings describing the effects on locomotor activity of the CBD precursor cannabidiolic acid and of CBD alone or in combination with THC, together with the effects of CBD on locomotor modifications induced by diseases and on locomotor changes induced by other substances.

Cannabis sativa and Cannabidiol: A Therapeutic Strategy for the Treatment of Neurodegenerative Diseases?

This work is a literature review, presenting the current state of the use of cannabinoids on neurodegenerative diseases. The emphasis is on Parkinson's (PD) and Alzheimer's (AD) diseases, the two most prevalent neurological diseases. The review goes from Cannabis sativa and its hundreds of bioactive compounds to Δ9-tetrahydrocannabinol (THC) and mainly cannabidiol (CBD) and their interactions with the endocannabinoid receptors (CB1 and CB2). CBD molecular targets were also focused on to explain its neuroprotective action mechanism on neurodegenerative diseases. Although THC is the main psychoactive component of C. sativa, and it may induce transient psychosis-like symptoms, growing evidence suggests that CBD may have protective effects against the psychotomimetic effects of THC and therapeutic properties. Furthermore, a great number of recent works on the neuroprotective and anti-inflammatory CBD effects and its molecular targets are also reviewed. We analyzed CBD actions in preclinical and in clinical trials, conducted with PD and AD patients. Although the data on preclinical assays are more convincing, the same is not true with the clinical data. Despite the consensus among researchers on the potential of CBD as a neuroprotective agent, larger and well-designed randomized clinical trials will be necessary to gather conclusive results concerning the use of CBD as a therapeutic strategy for the treatment of diseases such as PD and AD.