Activation of Cannabinoid CB2 Receptor–Mediated AMPK/CREB Pathway Reduces Cerebral Ischemic Injury

β-Caryophyllene (CB2 agonist) mitigates rotenone-induced neurotoxicity and apoptosis in SH-SY5Y neuroblastoma cells via modulation of GSK-3β/NRF2/HO-1 axis

Rotenone-induced neurotoxicity in SH-SY5Y cells is an essential hallmark of neurodegenerative diseases like Alzheimer's disease (AD) and Parkinson's disease (PD). β-Caryophyllene (BCP), a cannabinoid receptor 2 (CB2) agonist, has anti-inflammatory, antioxidant, and cytoprotective efficacy. The involvement of the GSK-3β/NRF2/HO-1 axis in neuroprotection has garnered attention as a possible mechanism for BCP to exhibit multitargeted neuroprotective effects. Hence, this study investigates the effects of BCP against rotenone-induced neurotoxicity and apoptosis in SH-SY5Y cells, focusing on the involvement of the GSK-3β/NRF2/HO-1 signaling pathway. Initially, we performed the in silico molecular docking of BCP with GSK-3β, NRF2, and HO-1 proteins to ensure the degree of binding affinities. The in vitro MTT assay was performed to evaluate cell viability, followed by the assessment of biomarkers such as LDH leakage, oxidative stress, reactive species, caspase 3 activity, pro-inflammatory markers, and GSK-3β, NRF2, and HO-1 proteins in BCP, as well as specific receptor modulators (chir98023 and quercetin) against the rotenone pre-treated cells. In silico molecular docking studies revealed that BCP exhibits a strong binding affinity for GSK-3β, NRF2, and HO-1 proteins. Also, in vitro studies revealed that BCP (100 µg/ml), as compared to the rotenone-treated group, significantly restored cell viability (72%). Moreover, BCP significantly modulates cell cytotoxicity (LDH leakage), pro-apoptotic, pro-inflammatory, reactive species, and oxidative stress markers. Molecular docking established robust binding affinities of BCP with GSK-3β, NRF2, and HO-1 proteins. Furthermore, protein estimation by ELISA confirmed the BCP-mediated modulation of these pathways. These findings suggest that BCP protects SH-SY5Y cells from rotenone-induced neurotoxicity, offering a potential therapeutic candidate for neurodegenerative diseases like AD.

Cannabinoid Receptor 2 (CB2R) as potential target for the pharmacological treatment of neurodegenerative diseases

The endocannabinoid system (ECS) is a ubiquitous physiological system that plays a crucial role in maintaining CNS homeostasis and regulating its functions. It includes cannabinoid receptors (CBRs), endogenous cannabinoids (eCBs), and the enzymes responsible for their synthesis and degradation. In recent years, growing evidence has highlighted the therapeutic potential of the ECS and CBRs, in a wide range of severe diseases and pathological conditions, including Alzheimer's and Parkinson's diseases, Amyotrophic Lateral Sclerosis, Multiple Sclerosis, Huntington's Disease, HIV-1 associated neurocognitive disorders, neuropathic pain and migraine. Targeting the cannabinoid type 2 receptor (CB2R) has gained attention due to its ability to (i) mitigate neuroinflammatory responses, (ii) regulate mitochondrial function and (iii) provide trophic support, all without eliciting the psychotropic actions associated with CB1R activation. This review aims to explore the potential of CB2R modulation as a strategy for the prevention and treatment of neurologic disorders, exploring both preclinical and clinical findings.

A comprehensive review of the multifaceted role of cannabinoid receptor type 2 in neurodegenerative and neuropsychiatric disorders

Research carried out during the last 30 years since the first identification of CB2r in 1993 has changed the landscape of this receptor's role and therapeutic utility. Initially, studies focused on elucidating the role of CB2r at the periphery since it was first characterized in spleen and lymphocytes. Later, CB2r was found in the brain not only under pathological conditions but also under basal conditions. It is now known that this receptor is expressed in different brain regions and different cell types, including neurons and microglia. Experimental studies have provided robust evidence that CB2r is involved in the modulation of the immune system, neuroinflammation, oxidative stress and neuroprotection. Besides, CB2r mediated the response to stress, anxiety, and depression. Also, CB2r plays a relevant role in modulating the reinforcing properties of different drugs of abuse, including alcohol, nicotine and cocaine. In this review, we summarize the cumulative knowledge regarding the immunomodulatory, anti-inflammatory, antioxidant, and neuroprotective properties of CB2r against the development of neurodegenerative diseases. Indeed, we cover the anxiolytic and antidepressant potential of CB2r, which raises the therapeutic interest of this receptor in different psychiatric diseases associated with anxiety and depression. Finally, we discuss the involvement of CB2r in the regulation of drug addiction. A better understanding of the properties of CB2r is essential for the pharmacological development of this receptor in different neurodegenerative, psychiatric, and addictive disorders.

The Effects of Cannabinoids on Ischemic Stroke-Associated Neuroinflammation: A Systematic Review

Stroke represents a significant burden on global health and the economy, with high mortality rates, disability, and recurrence. Ischemic stroke is a serious condition that occurs when a blood vessel in the brain is interrupted, reducing the blood supply to the affected area. Inflammation is a significant component in stroke pathophysiology. Neuroinflammation is triggered following the acute ischemic ictus, where the blood-brain barrier (BBB) breaks down, causing damage to the endothelial cells. The damage will eventually generate oxidative stress, activate the pathological phenotypes of astrocytes and microglia, and lead to neuronal death in the neurovascular unit. As a result, the brain unleashes a robust neuroinflammatory response, which can further worsen the neurological outcomes. Neuroinflammation is a complex pathological process involved in ischemic damage and repair. Finding new neuroinflammation molecular targets is essential to develop effective and safe novel treatment approaches against ischemic stroke. Accumulating studies have investigated the pharmacological properties of cannabinoids (CBs) for many years, and recent research has shown their potential therapeutic use in treating ischemic stroke in rodent models. These findings revealed promising impacts of CBs in reducing neuroinflammation and cellular death and ameliorating neurological deficits. In this review, we explore the possibility of the therapeutic administration of CBs in mitigating neuroinflammation caused by a stroke. We summarize the results from several preclinical studies evaluating the efficacy of CBs anti-inflammatory interventions in ischemic stroke. Although convincing preclinical evidence implies that CBs targeting neuroinflammation are promising for ischemic stroke, translating these findings into the clinical setting has proven to be challenging. The translation hurdle is due to the essence of the CBs ability to cause anxiety, cognitive deficit, and psychosis. Future studies are warranted to address the dose-beneficial effect of CBs in clinical trials of ischemic stroke-related neuroinflammation treatment.

Exploring β-caryophyllene: a non-psychotropic cannabinoid's potential in mitigating cognitive impairment induced by sleep deprivation

Sleep deprivation or sleep loss, a prevalent issue in modern society, is linked to cognitive impairment, leading to heightened risks of errors and accidents. Chronic sleep deprivation affects various cognitive functions, including memory, attention, and decision-making, and is associated with an increased risk of neurodegenerative diseases, cardiovascular issues, and metabolic disorders. This review examines the potential of β-caryophyllene, a dietary non-psychotropic cannabinoid, and FDA-approved flavoring agent, as a therapeutic solution for sleep loss-induced cognitive impairment. It highlights β-caryophyllene's ability to mitigate key contributors to sleep loss-induced cognitive impairment, such as inflammation, oxidative stress, neuronal death, and reduced neuroplasticity, by modulating various signaling pathways, including TLR4/NF-κB/NLRP3, MAPK, Nrf2/HO-1, PI3K/Akt, and cAMP/PKA/CREB. As a naturally occurring, non-psychotropic compound with low toxicity, β-caryophyllene emerges as a promising candidate for further investigation. The review underscores the therapeutic potential of β-caryophyllene for sleep loss-induced cognitive impairment and provides mechanistic insights into its action on crucial pathways, suggesting that β-caryophyllene could be a valuable addition to strategies aimed at combating cognitive impairment and other health issues due to sleep loss.

Electroacupuncture ameliorates inflammatory pain through CB2 receptor-dependent activation of the AMPK signaling pathway

BACKGROUND

Chronic inflammatory pain is a pervasive condition, and electroacupuncture (EA) is an effective treatment, but its mechanisms are not fully understood. AMP-activated protein kinase (AMPK), a key energy sensor, is involved in pain relief and EA's effects. EA may work by increasing endocannabinoids, upregulating CB2 receptors (CB2R), and stimulating β-endorphin (β-END). This study tests if EA activates AMPK via CB2R to modulate β-END and reduce pain.

METHODS

The inflammatory pain model was established with Complete Freund's adjuvant (CFA), and EA was administered daily for six consecutive days, targeting the acupoints "Zusanli" (ST36) and "Shangjuxu" (ST37). Pain sensitivity was evaluated using Von Frey filaments for mechanical thresholds and a hot plate for thermal thresholds. Ultra-high Performance Liquid Chromatography Tandem Mass Spectrometry (UPLC-MS/MS) was used to quantitatively determine the levels of endocannabinoids 2-arachidonoylglycerol (2-AG) and anandamide (AEA). The expression levels of the CB2R and β-END were measured by Western blotting, along with the activation of AMPK. Immunofluorescence double-labeling was applied to visualize AMPK activation and β-END expression within CD68-positive macrophages. The study encompassed both wild-type and CB2R gene knockout mice, elucidating the role of CB2R in EA-induced AMPK activation.

RESULTS

CFA-induced inflammatory pain model mice exhibited mechanical allodynia and thermal hyperalgesia. EA activated AMPK in the inflamed skin tissue when it exerted analgesic effect on the inflammatory pain. Pre-administration of the AMPK inhibitor Compound C significantly inhibited the effect of EA on pain relief. EA elevated β-END expression in inflamed skin tissue, which was reversed by Compound C, indicating that AMPK has a regulatory role in EA inducing β-END expression. In addition, EA significantly upregulated the levels of 2-AG, AEA and the expression of CB2Rs in the inflamed skin tissue compared with the CFA group. In wild-type mice, EA activates AMPK in macrophages, while CB2 knockout reduced EA's ability to activate AMPK in these cells.

CONCLUSION

EA activates AMPK through CB2R, enhancing β-END expression in inflamed skin to alleviate inflammatory pain. This study reveals a new link between endocannabinoids, endorphins, and AMPK in analgesic effects of EA, highlighting the CB2R-AMPK-β-END pathway.

Celastrol ameliorates hypoxic-ischemic brain injury in neonatal rats by reducing oxidative stress and inflammation

BACKGROUND

Hypoxic-ischemic encephalopathy (HIE) is caused by perinatal hypoxia and subsequent reductions in cerebral blood flow and is one of the leading causes of severe disability or death in newborns. Despite its prevalence, we currently lack an effective drug therapy to combat HIE. Celastrol (Cel) is a pentacyclic triterpene extracted from Tripterygium Wilfordi that can protect against oxidative stress, inflammation, and cancer. However, whether Cel can alleviate neonatal hypoxic-ischemic (HI) brain damage remains unclear.

METHODS

Here, we established both in vitro and in vivo models of HI brain damage using CoCl2-treated PC12 cells and neonatal rats, respectively, and explored the neuroprotective effects of Cel in these models.

RESULTS

Analyses revealed that Cel administration reduced brain infarction size, microglia activation, levels of inflammation factors, and levels of oxidative stress markers by upregulating levels of p-AMPKα, Nrf2, HO-1, and by downregulating levels of TXNIP and NLRP3. Conversely, these beneficial effects of Cel on HI brain damage were largely inhibited by AMPKα inhibitor Compound C and its siRNA.

CONCLUSIONS

We present compelling evidence that Cel decreases inflammation and oxidative stress through the AMPKα/Nrf2/TXNIP signaling pathway, thereby alleviating neonatal HI brain injury. Cel therefore represents a promising therapeutic agent for treating HIE.

IMPACT

We firstly report that celastrol can ameliorate neonatal hypoxic-ischemic brain injury both in in vivo and in vitro, which represents a promising therapeutic agent for treating related brain injuries. Celastrol activates the AMPKα/Nrf2/TXNIP signaling pathway to relieve oxidative stress and inflammation and thereby alleviates neonatal hypoxic-ischemic brain injury.

Cannabinoid receptor 2 agonist AM1241 alleviates epileptic seizures and epilepsy-associated depression via inhibiting neuroinflammation in a pilocarpine-induced chronic epilepsy mouse model

Increasing evidence suggests that cannabinoid receptor 2 (CB2R) serves as a promising anti-inflammatory target. While inflammation is known to play crucial roles in the pathogenesis of epilepsy, the involvement of CB2R in epilepsy remains unclear. This study aimed to investigate the effects of a CB2R agonist, AM1241, on epileptic seizures and depressive-like behaviors in a mouse model of chronic epilepsy induced by pilocarpine. A chronic epilepsy mouse model was established by intraperitoneal administration of pilocarpine. The endogenous cannabinoid system (eCBs) in the hippocampus was examined after status epilepticus (SE). Animals were then treated with AM1241 and compared with a vehicle-treated control group. Additionally, the role of the AMPK/NLRP3 signaling pathway was explored using the selective AMPK inhibitor dorsomorphin. Following SE, CB2R expression increased significantly in hippocampal microglia. Administration of AM1241 significantly reduced seizure frequency, immobility time in the tail suspension test, and neuronal loss in the hippocampus. In addition, AM1241 treatment attenuated microglial activation, inhibited pro-inflammatory polarization of microglia, and suppressed NLRP3 inflammasome activation in the hippocampus after SE. Further, the therapeutic effects of AM1241 were abolished by the AMPK inhibitor dorsomorphin. Our findings suggest that CB2R agonist AM1241 may alleviate epileptic seizures and its associated depression by inhibiting neuroinflammation through the AMPK/NLRP3 signaling pathway. These results provide insight into a novel therapeutic approach for epilepsy.

Beta-caryophyllene in psychiatric and neurological diseases: Role of blood-brain barrier

Beta-caryophyllene is an abundant terpene in cannabis, cinnamon, black pepper, cloves, and citrus fruit, delivering a striking, woody-spicy, like cloves and a sweet fruity aroma. Beta-caryophyllene is a Food and Drug Administration-approved food additive with Generally Recognized as Safe status. Interestingly, several biologic activities have been described for beta-caryophyllene, including anti-inflammatory and analgesic effects, neuroprotection against cerebral ischemia and neuronal injury, protection of neurovascular unit against oxidative damage, glial activation and neuroinflammation and anticonvulsant effects. In this chapter, we intend to review the beneficial effects of beta-caryophyllene in the context of psychiatric and neurological diseases. Also, we will analyze the possibility that the blood-brain-barrier may be a central target underlying the beneficial actions of beta-caryophyllene.

Exploring the therapeutic potential of natural compounds modulating the endocannabinoid system in various diseases and disorders: review

Cannabinoid receptors, endogenous cannabinoids (endocannabinoids), and the enzymes involved in the biosynthesis and degradation of the endocannabinoids make up the endocannabinoid system (ECS). The components of the ECS are proven to modulate a vast bulk of various physiological and pathological processes due to their abundance throughout the human body. Such discoveries have attracted the researchers' attention and emerged as a potential therapeutical target for the treatment of various diseases. In the present article, we reviewed the discoveries of natural compounds, herbs, herbs formula, and their therapeutic properties in various diseases and disorders by modulating the ECS. We also summarize the molecular mechanisms through which these compounds elicit their properties by interacting with the ECS based on the existing findings. Our study provides the insight into the use of natural compounds that modulate ECS in various diseases and disorders, which in turn may facilitate future studies exploiting natural lead compounds as novel frameworks for designing more effective and safer therapeutics.

Cannabinoids: Emerging sleep modulator

Sleep is an essential biological phase of our daily life cycle and is necessary for maintaining homeostasis, alertness, metabolism, cognition, and other key functions across the animal kingdom. Dysfunctional sleep leads to deleterious effects on health, mood, and cognition, including memory deficits and an increased risk of diabetes, stroke, and neurological disorders. Sleep is regulated by several brain neuronal circuits, neuromodulators, and neurotransmitters, where cannabinoids have been increasingly found to play a part in its modulation. Cannabinoids, a group of lipid metabolites, are regulatory molecules that bind mainly to cannabinoid receptors (CB1 and CB2). Much evidence supports the role of cannabinoid receptors in the modulation of sleep, where their alteration exhibits sleep-promoting effects, including an increase in non-rapid-eye movement sleep and a reduction in sleep latency. However, the pharmacological alteration of CB1 receptors is associated with adverse psychotropic effects, which are not exhibited in CB2 receptor alteration. Hence, selective alteration of CB2 receptors is also of clinical importance, where it could potentially be used in treating sleep disorders. Thus, it is crucial to understand the neurobiological basis of cannabinoids in sleep physiology. In this review article, the alteration of the endocannabinoid system by various cannabinoids and their respective effects on the sleep-wake cycle are discussed based on recent findings. The mechanisms of the cannabinoid receptors on sleep and wakefulness are also explored for their clinical implications and potential therapeutic use on sleep disorders.

Cannabinoid Receptor Type II Ligands from Sandalwood Oil and Synthetic α-Santalol Derivatives

Bioassay-guided fractionation of the essential oil of Santalum album led to the identification of α-santalol (1) and β-santalol (2) as new chemotypes of cannabinoid receptor type II (CB2) ligands with Ki values of 10.49 and 8.19 μM, respectively. Nine structurally new α-santalol derivatives (4a-4h and 5) were synthesized to identify more selective and potent CB2 ligands. Compound 4e with a piperazine structural moiety demonstrated a Ki value of 0.99 μM against CB2 receptor and did not show binding activity against cannabinoid receptor type I (CB1) at 10 μM. Compounds 1, 2, and 4e increased intracellular calcium influx in SH-SY5Y human neuroblastoma cells that were attenuated by CB2 antagonism or inverse agonism, supporting the results that these compounds are CB2 agonists. Molecular docking showed that 1 and 4e had similar binding poses, exhibiting a unique interaction with Thr114 within the CB2 receptor, and that the piperazine structural moiety is required for the binding affinity of 4e. A 200 ns molecular dynamics simulation of CB2 complexed with 4e confirmed the stability of the complex. This structural insight lays a foundation to further design and synthesize more potent and selective α-santalol-based CB2 ligands for drug discovery.

HU308 Mitigates Osteoarthritis by Stimulating Sox9-Related Networks of Carbohydrate Metabolism

Osteoarthritis (OA) is characterized by progressive, irreversible erosion of articular cartilage accompanied by severe pain and immobility. This study aimed to assess the effect and mechanism of action of HU308, a selective cannabinoid receptor type 2 (CB2) agonist, in preventing OA-related joint damage. To test the assumption that HU308 could prevent OA-related joint damage, Cnr2 null mice and wild type (WT) mice were aged to reach 20 months and analyzed for joint structural features. OA was induced in WT mice via a post-traumatic procedure or aging, followed by HU308 local (intra-articular) or systemic (intraperitoneal) administration, respectively. Additional analyses of time and dose courses for HU308 were carried out in human primary chondrocytes, analyzed by RNA sequencing, RT-PCR, chromatin immunoprecipitation, and immunoblotting. Our results showed that Cnr2 null mice exhibited enhanced age-related OA severity and synovitis compared to age-matched WT mice. Systemic administration of HU308 to 16-month-old mice improved pain sensitivity and maintained joint integrity, which was consistent with the intra-articular administration of HU308 in post-traumatic OA mice. When assessing human chondrocytes treated with HU308, we uncovered a dose- and time-related increase in ACAN and COL2A1 expression, which was preceded by increased SOX9 expression due to pCREB transcriptional activity. Finally, transcriptomic analysis of patient-derived human chondrocytes identified patient subpopulations exhibiting HU308-responsive trends as judged by enhanced SOX9 expression, accompanied by enriched gene networks related to carbohydrate metabolism. Collectively, the results showed that HU308 reduced trauma and age-induced OA via CB2-pCREB dependent activation of SOX9, contributing to augmented gene networks related to carbohydrate metabolism. © 2022 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).

Cannabinoid receptor-2 attenuates neuroinflammation by promoting autophagy-mediated degradation of the NLRP3 inflammasome post spinal cord injury

Background

Neuroinflammation following spinal cord injury (SCI) results in prolonged neurological damage and locomotor dysfunction. Polarization of microglia is vital to regulation of neuroinflammation, although the underlying mechanisms have not yet been elucidated. Endocannabinoid receptor subtype 2 (CB2R) is reported to ameliorate neurodegeneration via immunomodulation activities. However, the underlying machinery in the context of SCI remains unclear.

Methods

A lipopolysaccharide-induced microglia inflammation model and a mouse model of SCI were employed to investigate the regulatory role of CB2R in the polarization of microglia in response to excess neuroinflammation. Markers of inflammation and autophagy were measured by Western blot analysis, immunofluorescence, flow cytometry, and enzyme-linked immunosorbent assays. Histological staining with hematoxylin and eosin, Nissl, and Luxol^® fast blue was conducted using commercial kits. The locomotor function of the hindlimbs of the experimental mice was evaluated with the Basso Mouse Scale, Louisville Swim Scale, and footprint assay.

Results

The results showed that CB2R promoted M2 differentiation, increased interleukin (IL)-10 expression, and inhibited M1 differentiation with decreased expression of IL-1β and IL-6. CB2R activation also increased ubiquitination of the NLRP3 inflammasome and interacted with the autophagy-related proteins p62 and microtubule-associated proteins 1B light chain 3. Treatment with the CB2R activator JWH-133 reduced loss of myelin, apoptosis of neurons, and glial scarring, leading to improved functional recovery of the hindlimbs, while the CB2R antagonist AM630 produced opposite results.

Conclusion

Taken together, these results suggested that CB2R activation attenuated neuroinflammation targeting microglial polarization by promoting NLRP3 clearance, thereby facilitating functional recovery post-SCI.

Cannabinoid Effect and Safety in Spasticity Following Stroke: A Double-Blind Randomized Placebo-Controlled Study

Background

Nabiximols is a cannabis-based drug to treat spasticity-associated symptoms currently approved for patients with multiple sclerosis only. Cannabinoids are useful in an increasing number of medical conditions but may bear an increased risk for cardiovascular events. SativexStroke is a double-blind randomized placebo-controlled crossover monocentric clinical trial investigating the efficacy and safety of nabiximols in patients with spasticity following stroke.

Methods

Patients were treated with nabiximols oromucosal spray or placebo and assessed before and after two phases of 1-month duration each. Cardiovascular safety was assessed before and during the trial. Primary endpoints were changes in spasticity numeric rating scale scores and electromyographic recording of the stretch reflex in affected wrist flexors. Secondary outcome measures were numeric rating scale scores for pain, sleep and bladder function, the number of daily spasms and clinical assessment of spasticity with the modified Ashworth scale. The study was registered with the EudraCT number 2016-001034-10.

Results

Between May 2, 2018, and February 20, 2020, 41 patients entered the study. Seven patients did not complete the study, so 34 were included in the analysis. Two serious adverse events occurred, but none related to cardiovascular function. Primary and secondary efficacy outcome measures did not change from baseline during nabiximols treatment relative to placebo.

Conclusion

This study suggests that nabiximols use is probably safe in stroke patients, therefore cannabinoid usefulness may be further investigated. The lack of nabiximols effect could be related to low pain levels in recruited patients or different spasticity mechanisms between post-stroke and multiple sclerosis patients. Similarly, a beneficial effect of nabiximols could have emerged if more patients with a higher level of spasticity at baseline were recruited.

Clinical Trial Registration

https://www.clinicaltrialsregister.eu/ctr-search/trial/2016-001034-10/IT.

Cannabinoid receptor 2 engagement promotes group 2 innate lymphoid cell expansion and enhances airway hyperreactivity

BACKGROUND

Cannabinoids modulate the activation of immune cells and physiologic processes in the lungs. Group 2 innate lymphoid cells (ILC2s) are central players in type 2 asthma, but how cannabinoids modulate ILC2 activation remains to be elucidated.

OBJECTIVE

Our goal was to investigate the effects of cannabinoids on ILC2s and their role in asthma.

METHODS

A combination of cannabinoid receptor (CB)2 knockout (KO) mice, CB2 antagonist and agonist were used in the mouse models of IL-33, IL-25, and Alternaria alternata ILC2-dependent airway inflammation. RNA sequencing was performed to assess transcriptomic changes in ILC2s, and humanized mice were used to assess the role of CB2 signaling in human ILC2s.

RESULTS

We provide evidence that CB2 signaling in ILC2s is important for the development of ILC2-driven airway inflammation in both mice and human. We showed that both naive and activated murine pulmonary ILC2s express CB2. CB2 signaling did not affect ILC2 homeostasis at steady state, but strikingly it stimulated ILC2 proliferation and function upon activation. As a result, ILC2s lacking CB2 induced lower lung inflammation, as we made similar observations using a CB2 antagonist. Conversely, CB2 agonism remarkably exacerbated ILC2-driven airway hyperreactivity and lung inflammation. Mechanistically, transcriptomic and protein analysis revealed that CB2 signaling induced cyclic adenosine monophosphate-response element binding protein (CREB) phosphorylation in ILC2s. Human ILC2s expressed CB2, as CB2 antagonism and agonism showed opposing effects on ILC2 effector function and development of airway hyperreactivity in humanized mice.

CONCLUSION

Collectively, our results define CB2 signaling in ILC2s as an important modulator of airway inflammation.

Improved cognition impairment by activating cannabinoid receptor type 2: Modulating CREB/BDNF expression and impeding TLR-4/NFκBp65/M1 microglia signaling pathway in D-galactose-injected ovariectomized rats

Alzheimer's disease (AD) is characterized by an active inflammatory response induced by the brain's deposition and accumulation of amyloid-beta (Aβ). Cannabinoid receptor type 2 (CB2R) is expressed in specific brain areas, modulating functions, and pathophysiologies in CNS. Herein, we aimed to evaluate whether activation of CB2R can improve the cognitive impairment in the experimental AD-like model and determine the involved intracellular signaling pathway. Injection of D-galactose (150 mg/kg, i.p.) was performed to urge AD-like features in bilaterally ovariectomized female rats (OVC/D-gal rats) for 8-weeks. Then, AM1241, a CB2R-agonist (3 and 6 mg/kg), was injected intraperitoneally starting from the 6th week. Treatment with AM1241, significantly down-regulated; Toll-like receptor4 (TLR4), Myd88 (TLR4-adaptor protein) genes expression, and the pro-inflammatory cytokines (NFκB p65, TNF-α, IL-6, and IL-12). In contrast, it enhanced BDNF (the brain-derived neurotrophic factor) and CREB (the cyclic AMP response element-binding protein) as well as the immune-modulatory cytokines (IL-4 and IL-10) levels. Moreover, AM1241 lessened the immune-expression of GFAP, CD68, caspase-3, and NFκB p65 markers and mended the histopathological damage observed in OVC/D-gal rats by decreasing the deposition of amyloid plaques and degenerative neuronal lesions, as well as improving their recognition and learning memory in both novel object recognition and Morris water maze tests. In conclusion, activating CB2R by the selective agonist AM1241 can overrun cognitive deficits in OVC/D-gal rats through modulation of TLR4/ NFκB p65 signaling, mediated by modulating CREB/BDNF pathway, thereby can be applied as a potential therapeutic strategy in AD treatment.

Anti-Inflammatory Effect of Beta-Caryophyllene Mediated by the Involvement of TRPV1, BDNF and trkB in the Rat Cerebral Cortex after Hypoperfusion/Reperfusion

We have previously shown that bilateral common carotid artery occlusion followed by reperfusion (BCCAO/R) is a model to study early hypoperfusion/reperfusion-induced changes in biomarkers of the tissue physiological response to oxidative stress and inflammation. Thus in this study, we investigate with immunochemical assays if a single dose of beta-caryophyllene (BCP), administered before the BCCAO/R, can modulate the TRPV1, BDNF, and trkB receptor in the brain cortex; the glial markers GFAP and Iba1 were also examined. Frontal and temporal-occipital cortical regions were analyzed in two groups of male rats, sham-operated and submitted to BCCAO/R. Six hours before surgery, one group was gavage fed a dose of BCP (40 mg/per rat in 300 μL of sunflower oil), the other was pre-treated with the vehicle alone. Western blot analysis showed that, in the frontal cortex of vehicle-treated rats, the BCCAO/R caused a TRPV1 decrease, an increment of trkB and GFAP, no change in BDNF and Iba1. The BCP treatment caused a decrease of BDNF and an increase of trkB levels in both sham and BCCAO/R conditions while inducing opposite changes in the case of TRPV1, whose levels became higher in BCCAO/R and lower in sham conditions. Present results highlight the role of BCP in modulating early events of the cerebral inflammation triggered by the BCCAO/R through the regulation of TRPV1 and the BDNF-trkB system.

Beta-caryophyllene attenuates short-term recurrent seizure activity and blood-brain-barrier breakdown after pilocarpine-induced status epilepticus in rats

BACKGROUND

Status epilepticus (SE) is a neurological life-threatening condition, resulting from the failure of the mechanisms responsible for seizure termination. SE is often pharmacoresistant and associated with significant morbidity and mortality. Hence, ceasing or attenuating SE and its consequences is of fundamental importance. Beta-caryophyllene is a functional CB2 receptor agonist and exhibit a good safety profile. Besides, it displays beneficial effects in several experimental conditions, including neuroprotective activity. In the present study we aimed to investigate the effects of beta-caryophyllene on pilocarpine-induced SE.

METHODS

Wistar rats were submitted to pilocarpine-induced SE and monitored for 24 hours by video and EEG for short-term recurrence of seizure activity (i.e. seizures occurring within 24 hours after termination of SE). Rats received beta-caryophyllene (100 mg/kg, ip) at 1, 8- and 16-hours after SE. Twenty-four hours after SE we evaluated sensorimotor response, neuronal damage (fluoro jade C staining) and serum albumin infiltration into brain parenchyma.

RESULTS

Beta-caryophyllene-treated animals presented fewer short-term recurrent seizures than vehicle-treated counterparts, suggesting an anticonvulsant effect after SE. Behavioral recovery from SE and the number of fluoro jade C positive cells in the hippocampus and thalamus were not modified by beta-caryophyllene. Treatment with beta-caryophyllene attenuated the SE-induced increase of albumin immunoreactivity in the hippocampus, indicating a protective effect against blood-brain-barrier breakdown.

CONCLUSIONS

Given the inherent difficulties in the treatment of SE and its consequences, present results suggest that beta-caryophyllene deserve further investigation as an adjuvant therapeutic strategy for SE.

Intertwined associations between oxidative and nitrosative stress and endocannabinoid system pathways: Relevance for neuropsychiatric disorders

The endocannabinoid system (ECS) appears to regulate metabolic, cardiovascular, immune, gastrointestinal, lung, and reproductive system functions, as well as the central nervous system. There is also evidence that neuropsychiatric disorders are associated with ECS abnormalities as well as oxidative and nitrosative stress pathways. The goal of this mechanistic review is to investigate the mechanisms underlying the ECS's regulation of redox signalling, as well as the mechanisms by which activated oxidative and nitrosative stress pathways may impair ECS-mediated signalling. Cannabinoid receptor (CB)1 activation and upregulation of brain CB2 receptors reduce oxidative stress in the brain, resulting in less tissue damage and less neuroinflammation. Chronically high levels of oxidative stress may impair CB1 and CB2 receptor activity. CB1 activation in peripheral cells increases nitrosative stress and inducible nitric oxide (iNOS) activity, reducing mitochondrial activity. Upregulation of CB2 in the peripheral and central nervous systems may reduce iNOS, nitrosative stress, and neuroinflammation. Nitrosative stress may have an impact on CB1 and CB2-mediated signalling. Peripheral immune activation, which frequently occurs in response to nitro-oxidative stress, may result in increased expression of CB2 receptors on T and B lymphocytes, dendritic cells, and macrophages, reducing the production of inflammatory products and limiting the duration and intensity of the immune and oxidative stress response. In conclusion, high levels of oxidative and nitrosative stress may compromise or even abolish ECS-mediated redox pathway regulation. Future research in neuropsychiatric disorders like mood disorders and deficit schizophrenia should explore abnormalities in these intertwined signalling pathways.

LncRNA CEBPA-AS1 knockdown prevents neuronal apoptosis against oxygen glucose deprivation/reoxygenation by regulating the miR-455/GPER1 axis

Ischemic stroke (IS) is a common nervous system disease, which is a major cause of disability and death in the world. In present study, we demonstrated a regulatory mechanism of CCAAT/enhancer binding protein-alpha antisense 1 (CEBPA-AS1) in oxygen glucose deprivation/reoxygenation (OGD/R)-induced SH-SY5Y cells, with a focus on neuronal apoptosis. CEBPA-AS1, miR-455, and GPER1 expressions were evaluated by using qRT-PCR and Western blotting. The binding relationship among CEBPA-AS1, miR-455, and GPER1 was determined by a dual luciferase reporter assay. Neuronal viability and apoptosis were examined using MTT and flow cytometry assays, followed by determination of apoptosis-related factors (caspase 3, caspase 8, caspase 9, Bax, and Bcl-2). CEBPA-AS1 and GPER1 levels were upregulated, and miR-455 level was downregulated in the cell model of OGD/R induced. CEBPA-AS1 knockdown increased SH-SY5Y viability and reduced OGD/R-induced apoptosis. CEBPA-AS1 could act as a sponge of miR-455, and CEBPA-AS1 knockdown was found to elevate miR-455 expression. miR-455 overexpression also promoted SH-SY5Y cell viability and rescued them from OGD/R-induced apoptosis by binding to GPER1. GPER1 overexpression or miR-455 inhibition reversed the anti-apoptotic effect of CEBPA-AS1 knockdown. These findings suggest a regulatory network of CEBPA-AS1/miR-455/GPER1 that mediates neuronal cell apoptosis in the OGD model, providing a better understanding of pathogenic mechanisms after IS.

Sult2b1 deficiency exacerbates ischemic stroke by promoting pro-inflammatory macrophage polarization in mice

Rationale: Stroke is a leading causes of human death worldwide. Ischemic damage induces the sterile neuroinflammation, which directly determines the recovery of patients. Lipids, a major component of the brain, significantly altered after stroke. Cholesterol sulfate, a naturally occurring analog of cholesterol, can directly regulate immune cell activation, indicating the possible involvement of cholesterol metabolites in neuroinflammation. Sulfotransferase family 2b member 1 (Sult2b1) is the key enzyme that catalyzes the synthesis of cholesterol sulfate. This study aimed to investigate the function of Sult2b1 and cholesterol sulfate in the neuroinflammation after ischemic stroke.

Methods and Results: Sult2b1^-/- and wild-type mice were subjected to transient middle cerebral artery occlusion. Our data showed that Sult2b1^-/- mice had larger infarction and worse neurological scores. To determine whether immune cells were involved in the worsening stroke outcome in Sult2b1^-/- mice, bone marrow transplantation, immune cell depletion, and adoptive monocyte transfer were performed. Combined with CyTOF and immunofluorescence techniques, we demonstrated that after stroke, the peripheral monocyte-derived macrophages were the dominant cell type promoting the pro-inflammatory status in Sult2b1^-/-mice. Using primary bone marrow-derived macrophages, we showed that cholesterol sulfate could attenuate the pro-inflammatory polarization of macrophages under both normal and oxygen-glucose deprivation conditions by regulating the levels of nicotinamide adenine dinucleotide phosphate (NADPH), reactive oxygen species (ROS), and activating the AMP-activated protein kinase (AMPK) - cAMP responsive element-binding protein (CREB) signaling pathway.

Conclusions:Sult2b1^-/- promoted the polarization of macrophages into pro-inflammatory status. This trend could be attenuated by adding cholesterol sulfate, which promotes the polarization of macrophages into anti-inflammatory status by metabolic regulation. In this study, we established an inflammation-metabolism axis during the macrophage polarization after ischemic stroke.

Quality of Life and a Surveillant Endocannabinoid System

The endocannabinoid system (ECS) is an important brain modulatory network. ECS regulates brain homeostasis throughout development, from progenitor fate decision to neuro- and gliogenesis, synaptogenesis, brain plasticity and circuit repair, up to learning, memory, fear, protection, and death. It is a major player in the hypothalamic-peripheral system-adipose tissue in the regulation of food intake, energy storage, nutritional status, and adipose tissue mass, consequently affecting obesity. Loss of ECS control might affect mood disorders (anxiety, hyperactivity, psychosis, and depression), lead to drug abuse, and impact neurodegenerative (Alzheimer's, Parkinson, Huntington, Multiple, and Amyotrophic Lateral Sclerosis) and neurodevelopmental (autism spectrum) disorders. Practice of regular physical and/or mind-body mindfulness and meditative activities have been shown to modulate endocannabinoid (eCB) levels, in addition to other players as brain-derived neurotrophic factor (BDNF). ECS is involved in pain, inflammation, metabolic and cardiovascular dysfunctions, general immune responses (asthma, allergy, and arthritis) and tumor expansion, both/either in the brain and/or in the periphery. The reason for such a vast impact is the fact that arachidonic acid, a precursor of eCBs, is present in every membrane cell of the body and on demand eCBs synthesis is regulated by electrical activity and calcium shifts. Novel lipid (lipoxins and resolvins) or peptide (hemopressin) players of the ECS also operate as regulators of physiological allostasis. Indeed, the presence of cannabinoid receptors in intracellular organelles as mitochondria or lysosomes, or in nuclear targets as PPARγ might impact energy consumption, metabolism and cell death. To live a better life implies in a vigilant ECS, through healthy diet selection (based on a balanced omega-3 and -6 polyunsaturated fatty acids), weekly exercises and meditation therapy, all of which regulating eCBs levels, surrounded by a constructive social network. Cannabidiol, a diet supplement has been a major player with anti-inflammatory, anxiolytic, antidepressant, and antioxidant activities. Cognitive challenges and emotional intelligence might strengthen the ECS, which is built on a variety of synapses that modify human behavior. As therapeutically concerned, the ECS is essential for maintaining homeostasis and cannabinoids are promising tools to control innumerous targets.

Microglia and BDNF at the crossroads of stressor related disorders: Towards a unique trophic phenotype

Stressors ranging from psychogenic/social to neurogenic/injury to systemic/microbial can impact microglial inflammatory processes, but less is known regarding their effects on trophic properties of microglia. Recent studies do suggest that microglia can modulate neuronal plasticity, possibly through brain derived neurotrophic factor (BDNF). This is particularly important given the link between BDNF and neuropsychiatric and neurodegenerative pathology. We posit that certain activated states of microglia play a role in maintaining the delicate balance of BDNF release onto neuronal synapses. This focused review will address how different "activators" influence the expression and release of microglial BDNF and address the question of tropomyosin receptor kinase B (TrkB) expression on microglia. We will then assess sex-based differences in microglial function and BDNF expression, and how microglia are involved in the stress response and related disorders such as depression. Drawing on research from a variety of other disorders, we will highlight challenges and opportunities for modulators that can shift microglia to a "trophic" phenotype with a view to potential therapeutics relevant for stressor-related disorders.

Evaluation of the effects of metformin as adenosine monophosphate-activated protein kinase activator on spatial learning and memory in a rat model of multiple sclerosis disease

In patients with multiple sclerosis (MS) disease, cognitive deficits have been detected because of destruction of hippocampus. Cognitive impairment is one of the common signs in MS. Recent studies showed that metformin (Met) has wide-ranging effects in the treatment of diseases. Here, we have tried to study the preservative effects of Met as adenosine monophosphate-activated protein kinase (AMPK) activator on the hippocampus dentate gyrus (DG) neuronal firing pattern, motor coordination, and learning & memory loss following MS induction. The MS induction was done by local ethidium bromide (EB) injection into the rat hippocampus. Then, rats were treated with Met (200 mg/kg) for two weeks. Spatial memory and learning status were assessed using Morris water maze. A neuronal single-unit recording was measured from hippocampus DG. After decapitation, the bilateral hippocampi separated to measure malondialdehyde (MDA). Treatment with Met ameliorated latency times and path lengths (P < 0.05, P < 0.01, P < 0.001 in 1th, 2th, 3th and 4th days) in the Met + MS group respectively. The percent of total time spent in goal quarter and the average number of spikes/bin were decreased significantly in MS rats compared with the sham group (p < 0.001) but significantly increased in the metformin-treated MS group (Met + MS), (p < 0.01, p < 0.001). Met treatment in rats with MS significantly reduced the concentration of MDA, which is an indicator of lipid peroxidation compared to untreated groups. These observations show that increase of neuronal activity, sensory-motor coordination, and improvement of spatial memory in MS rats treated with Met appears via an increment of AMPK.

Pharmacological potential of JWH133, a cannabinoid type 2 receptor agonist in neurodegenerative, neurodevelopmental and neuropsychiatric diseases

The pharmacological activation of cannabinoid type 2 receptors (CB2R) gained attention due to its ability to mitigate neuroinflammatory events without eliciting psychotropic actions, a limiting factor for the drugs targeting cannabinoid type 1 receptors (CB1R). Therefore, ligands activating CB2R are receiving enormous importance for therapeutic targeting in numerous neurological diseases including neurodegenerative, neuropsychiatric and neurodevelopmental disorders as well as traumatic injuries and neuropathic pain where neuroinflammation is a common accompaniment. Since the characterization of CB2R, many CB2R selective synthetic ligands have been developed with high selectivity and functional activity. Among numerous ligands, JWH133 has been found one of the compounds with high selectivity for CB2R. JWH133 has been reported to exhibit numerous pharmacological activities including antioxidant, anti-inflammatory, anticancer, cardioprotective, hepatoprotective, gastroprotective, nephroprotective, and immunomodulatory. Recent studies have shown that JWH133 possesses potent neuroprotective properties in several neurological disorders, including neuropathic pain, anxiety, epilepsy, depression, alcoholism, psychosis, stroke, and neurodegeneration. Additionally, JWH133 showed to protect neurons from oxidative damage and inflammation, promote neuronal survival and neurogenesis, and serve as an immunomodulatory agent. The present review comprehensively examined neuropharmacological activities of JWH133 in neurological disorders including neurodegenerative, neurodevelopmental and neuropsychiatric using synoptic tables and elucidated pharmacological mechanisms based on reported observations. Considering the cumulative data, JWH133 appears to be a promising CB2R agonist molecule for further evaluation and it can be a prototype agent in drug discovery and development for a unique class of agents in neurotherapeutics. Further, regulatory toxicology and pharmacokinetic studies are required to determine safety and proceed for clinical evaluation.

G-Protein-Coupled Receptors and Ischemic Stroke: a Focus on Molecular Function and Therapeutic Potential

In ischemic stroke, there is only one approved drug, tissue plasminogen activator, to be used in clinical conditions for thrombolysis. New neuroprotective therapies for ischemic stroke are desperately needed. Several targets and pathways have been shown to confer neuroprotective effects in ischemic stroke. G-protein-coupled receptors (GPCRs) are one of the most frequently targeted receptors for developing novel therapeutics for central nervous system disorders. GPCRs are a large family of cell surface receptors that response to a wide variety of extracellular stimuli. GPCRs are involved in a wide range of physiological and pathological processes. More than 90% of the identified non-sensory GPCRs are expressed in the brain, where they play important roles in regulating mood, pain, vision, immune responses, cognition, and synaptic transmission. There is also good evidence that GPCRs are implicated in the pathogenesis of stroke. This review narrates the pathophysiological role and possible targeted therapy of GPCRs in ischemic stroke.

The endocannabinoidome in neuropsychiatry: Opportunities and potential risks

The endocannabinoid system (ECS) comprises two cognate endocannabinoid receptors referred to as CB1R and CB2R_. ECS dysregulation is apparent in neurodegenerative/neuro-psychiatric disorders including but not limited to schizophrenia, major depressive disorder and potentially bipolar disorder. The aim of this paper is to review mechanisms whereby both receptors may interact with neuro-immune and neuro-oxidative pathways, which play a pathophysiological role in these disorders. CB1R is located in the presynaptic terminals of GABAergic, glutamatergic, cholinergic, noradrenergic and serotonergic neurons where it regulates the retrograde suppression of neurotransmission. CB1R plays a key role in long-term depression, and, to a lesser extent, long-term potentiation, thereby modulating synaptic transmission and mediating learning and memory. Optimal CB1R activity plays an essential neuroprotective role by providing a defense against the development of glutamate-mediated excitotoxicity, which is achieved, at least in part, by impeding AMPA-mediated increase in intracellular calcium overload and oxidative stress. Moreover, CB1R activity enables optimal neuron-glial communication and the function of the neurovascular unit. CB2R receptors are detected in peripheral immune cells and also in central nervous system regions including the striatum, basal ganglia, frontal cortex, hippocampus, amygdala as well as the ventral tegmental area. CB2R upregulation inhibits the presynaptic release of glutamate in several brain regions. CB2R activation also decreases neuroinflammation partly by mediating the transition from a predominantly neurotoxic "M1" microglial phenotype to a more neuroprotective "M2" phenotype. CB1R and CB2R are thus novel drug targets for the treatment of neuro-immune and neuro-oxidative disorders including schizophrenia and affective disorders.

A focused review on CB2 receptor-selective pharmacological properties and therapeutic potential of β-caryophyllene, a dietary cannabinoid

The endocannabinoid system (ECS), a conserved physiological system emerged as a novel pharmacological target for its significant role and potential therapeutic benefits ranging from neurological diseases to cancer. Among both, CB1 and CB2R types, CB2R have received attention for its pharmacological effects as antioxidant, anti-inflammatory, immunomodulatory and antiapoptotic that can be achieved without causing psychotropic adverse effects through CB1R. The ligands activate CB2R are of endogenous, synthetic and plant origin. In recent years, β-caryophyllene (BCP), a natural bicyclic sesquiterpene in cannabis as well as non-cannabis plants, has received attention due to its selective agonist property on CB2R. BCP has been well studied in a variety of pathological conditions mediating CB2R selective agonist property. The focus of the present manuscript is to represent the CB2R selective agonist mediated pharmacological mechanisms and therapeutic potential of BCP. The present narrative review summarizes insights into the CB2R-selective pharmacological properties and therapeutic potential of BCP such as cardioprotective, hepatoprotective, neuroprotective, nephroprotective, gastroprotective, chemopreventive, antioxidant, anti-inflammatory, and immunomodulator. The available evidences suggest that BCP, can be an important candidate of plant origin endowed with CB2R selective properties that may provide a pharmacological rationale for its pharmacotherapeutic application and pharmaceutical development like a drug. Additionally, given the wide availability in edible plants and dietary use, with safety, and no toxicity, BCP can be promoted as a nutraceutical and functional food for general health and well-being. Further, studies are needed to explore pharmacological and pharmaceutical opportunities for therapeutic and preventive applications of use of BCP in human diseases.

Mediterranean Diet and Neurodegenerative Diseases: The Neglected Role of Nutrition in the Modulation of the Endocannabinoid System

Neurodegenerative disorders are a widespread cause of morbidity and mortality worldwide, characterized by neuroinflammation, oxidative stress and neuronal depletion. The broad-spectrum neuroprotective activity of the Mediterranean diet is widely documented, but it is not yet known whether its nutritional and caloric balance can induce a modulation of the endocannabinoid system. In recent decades, many studies have shown how endocannabinoid tone enhancement may be a promising new therapeutic strategy to counteract the main hallmarks of neurodegeneration. From a phylogenetic point of view, the human co-evolution between the endocannabinoid system and dietary habits could play a key role in the pro-homeostatic activity of the Mediterranean lifestyle: this adaptive balance among our ancestors has been compromised by the modern Western diet, resulting in a “clinical endocannabinoid deficiency syndrome”. This review aims to evaluate the evidence accumulated in the literature on the neuroprotective, immunomodulatory and antioxidant properties of the Mediterranean diet related to the modulation of the endocannabinoid system, suggesting new prospects for research and clinical interventions against neurodegenerative diseases in light of a nutraceutical paradigm.

β-Caryophyllene, A Natural Dietary CB2 Receptor Selective Cannabinoid can be a Candidate to Target the Trinity of Infection, Immunity, and Inflammation in COVID-19

Coronavirus disease (COVID-19), caused by novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is an ongoing pandemic and presents a public health emergency. It has affected millions of people and continues to affect more, despite tremendous social preventive measures. Identifying candidate drugs for the prevention and treatment of COVID-19 is crucial. The pathogenesis and the complications with advanced infection mainly involve an immune-inflammatory cascade. Therefore, therapeutic strategy relies on suppressing infectivity and inflammation, along with immune modulation. One of the most promising therapeutic targets for the modulation of immune-inflammatory responses is the endocannabinoid system, particularly the activation of cannabinoid type 2 receptors (CB2R), a G-protein coupled receptor which mediates the anti-inflammatory properties by modulating numerous signaling pathways. To pharmacologically activate the CB2 receptors, a naturally occurring cannabinoid ligand, beta-caryophyllene (BCP), received attention due to its potent anti-inflammatory, antiviral, and immunomodulatory properties. BCP is recognized as a full selective functional agonist on CB2 receptors and produces therapeutic effects by activating CB2 and the nuclear receptors, peroxisome proliferator-activated receptors (PPARs). BCP is regarded as the first dietary cannabinoid with abundant presence across cannabis and non-cannabis plants, including spices and other edible plants. BCP showed tissue protective properties and favorably modulates numerous signaling pathways and inhibits inflammatory mediators, including cytokines, chemokines, adhesion molecules, prostanoids, and eicosanoids. Based on its pharmacological properties, molecular mechanisms, and the therapeutic potential of BCP as an immunomodulator, anti-inflammatory, organ-protective, and antiviral, we hypothesize that BCP could be a promising therapeutic and/or preventive candidate to target the triad of infection, immunity, and inflammation in COVID-19. In line with numerous studies that proposed the potential of cannabinoids in COVID-19, BCP may be a novel candidate compound for pharmaceutical and nutraceutical development due to its unique functional receptor selectivity, wide availability and accessibility, dietary bioavailability, nonpsychoactivity, and negligible toxicity along with druggable properties, including favorable pharmacokinetic and physicochemical properties. Based on reasonable pharmacological mechanisms and therapeutic properties, we speculate that BCP has potential to be investigated against COVID-19 and will inspire further preclinical and clinical studies.

Circular RNA circ_HECTD1 regulates cell injury after cerebral infarction by miR-27a-3p/FSTL1 axis

Cerebral infarction is a common cerebrovascular disease caused by neural cell injury, with high mortality worldwide. Circular RNAs HECT domain E3 ubiquitin-protein ligase 1 (circ_HECTD1) has been reported to be related to the oxygen-glucose deprivation/reperfusion (OGD/R)-caused neuronal damage in cerebral ischemia. This study is designed to explore the role and mechanism of circ_HECTD1 in OGD/R-induced cell injury in cerebral ischemia. Circ_HECTD1, microRNA-27a-3p (miR-27a-3p), and Follistatin-like 1 (FSTL1) level were detected by real-time quantitative polymerase chain reaction (RT-qPCR). The localization of circ_HECTD1 was analyzed by subcellular fractionation assay. Cell proliferative ability and apoptosis were assessed by 5-ethynyl-2'-deoxyuridine (EdU), 3-(4, 5-dimethyl-2-thiazolyl)-2, 5-diphenyl-2-H-tetrazolium bromide (MTT), and flow cytometry assays. The protein levels of proliferating cell nuclear antigen (PCNA), B-cell lymphoma-2 (Bcl-2), Bcl-2 related X protein (Bax), Cleaved poly-ADP-ribose polymerase (PARP), and FSTL1 were examined by western blot assay. The binding relationship between miR-27a-3p and circ_HECTD1 or FSTL1 was predicted by starbase 3.0 then verified by a dual-luciferase reporter assay. Circ_HECTD1 and FSTL1 were highly expressed, and miR-27a-3p was decreased in OGD/R-treated HT22 cells. Moreover, circ_HECTD1 knockdown could boost cell proliferative ability and repress apoptosis in OGD/R-triggered HT22 cells in vitro. Mechanical analysis discovered that circ_HECTD1 could regulate FSTL1 expression by sponging miR-27a-3p. Circ_HECTD1 deficiency could mitigate OGD/R-induced HT22 cell damage by modulating the miR-27a-3p/FSTL1 axis, providing a promising therapeutic target for cerebral infarction treatment.

Metformin prevents stroke damage in non-diabetic female mice with chronic kidney disease

Chronic kidney disease (CKD) worsens ischemic stroke severity in both patients and animals. In mice, these poorer functional outcomes are associated with decreased brain activity of AMP-activated protein kinase (AMPK), a molecule that recently emerged as a potential therapeutic target for ischemic stroke. The antidiabetic drug metformin, a well-known activator of AMPK, has improved stroke outcomes in diabetic patients with normal renal function. We investigated whether chronic metformin pre-conditioning can rescue AMPK activity and prevent stroke damage in non-diabetic mice with CKD. Eight-week-old female C57BL/6J mice were assigned to CKD or SHAM groups. CKD was induced through right kidney cortical electrocautery, followed by left total nephrectomy. Mice were then allocated to receive metformin (200 mg/kg/day) or vehicle for 5 weeks until stroke induction by transient middle cerebral artery occlusion (tMCAO). The infarct volumes were lower in CKD mice exposed to metformin than in vehicle-treated CKD mice 24 h after tMCAO. Metformin pre-conditioning of CKD mice improved their neurological score, grip strength, and prehensile abilities. It also enhanced AMPK activation, reduced apoptosis, increased neuron survival and decreased microglia/macrophage M1 signature gene expression as well as CKD-induced activation of the canonical NF-κB pathway in the ischemic lesions of CKD mice.

Plant-Derived Trans-β-Caryophyllene Boosts Glucose Metabolism and ATP Synthesis in Skeletal Muscle Cells through Cannabinoid Type 2 Receptor Stimulation

Skeletal muscle plays a pivotal role in whole-body glucose metabolism, accounting for the highest percentage of glucose uptake and utilization in healthy subjects. Impairment of these key functions occurs in several conditions including sedentary lifestyle and aging, driving toward hyperglycemia and metabolic chronic diseases. Therefore, strategies pointed to improve metabolic health by targeting skeletal muscle biochemical pathways are extremely attractive. Among them, we focused on the natural sesquiterpene and cannabinoid type 2 (CB2) receptor agonist Trans-β-caryophyllene (BCP) by analyzing its role in enhancing glucose metabolism in skeletal muscle cells. Experiments were performed on C2C12 myotubes. CB2 receptor membrane localization in myotubes was assessed by immunofluorescence. Within glucose metabolism, we evaluated glucose uptake (by the fluorescent glucose analog 2-NBDG), key enzymes of both glycolytic and oxidative pathways (by spectrophotometric assays and metabolic radiolabeling) and ATP production (by chemiluminescence-based assays). In all experiments, CB2 receptor involvement was tested with the CB2 antagonists AM630 and SR144528. Our results show that in myotubes, BCP significantly enhances glucose uptake, glycolytic and oxidative pathways, and ATP synthesis through a CB2-dependent mechanism. Giving these outcomes, CB2 receptor stimulation by BCP could represent an appealing tool to improve skeletal muscle glucose metabolism, both in physiological and pathological conditions.

Cannabinoid Receptors in Metabolic Regulation and Diabetes

There is an urgent need for developing effective drugs to combat the obesity and Type 2 diabetes mellitus epidemics. The endocannabinoid system plays a major role in energy homeostasis. It comprises the cannabinoid receptors 1 and 2 (CB₁ and CB₂), endogenous ligands called endocannabinoids and their metabolizing enzymes. Because the CB₁ receptor is overactivated in metabolic alterations, pharmacological blockade of the CB₁ receptor arose as a promising candidate to treat obesity. However, because of the wide distribution of CB₁ receptors in the central nervous system, their negative central effects halted further therapeutic use. Although the CB₂ receptor is mostly peripherally expressed, its role in metabolic homeostasis remains unclear. This review discusses the potential of CB₁ and CB₂ receptors at the peripheral level to be therapeutic targets in metabolic diseases. We focus on the impact of pharmacological intervention and/or silencing on peripheral cannabinoid receptors in organs/tissues relevant for energy homeostasis. Moreover, we provide a perspective on novel therapeutic strategies modulating these receptors. Targeting CB₁ with peripherally restricted antagonists, neutral antagonists, inverse agonists, or monoclonal antibodies could represent successful strategies. CB₂ agonism has shown promising results at preclinical level. Beyond classic antagonism and agonism targeting orthosteric sites, the recently described crystal structures of CB₁ and CB₂ open new possibilities for therapeutic interventions with negative and positive allosteric modulators. The challenge of simultaneously targeting CB₁ and CB₂ might be possible by developing dual-steric ligands. The future will tell whether these promising strategies result in a renaissance of the cannabinoid receptors as therapeutic targets in metabolic diseases.

Circular RNA circPHC3 Promotes Cell Death and Apoptosis in Human BMECs After Oxygen Glucose Deprivation via miR-455-5p/TRAF3 Axis in vitro

OBJECTIVE

Brain microvascular endothelial cells (BMECs) are involved in brain vascular dysfunction in ischemic stroke. Abnormal expression of circular RNAs regulate physiological and pathophysiological processes in the central nervous system. The aim of the present study was to investigate profile circRNAs in human BMECs after oxygen glucose deprivation (OGD), which was an in vitro model of ischemic stroke, and find promising biomarkers in ischemic stroke.

METHODS

RNA sequencing (RNA-seq) technology was conducted to analyze the differential expression of circRNAs between BMECs after OGD and non-OGD treated BMECs. RT-qPCR, cell proliferation, cell apoptosis and dual-luciferase assay, and so on, were used to investigate the functions and molecular mechanisms of hsa_circ_0001360 (named circPHC3 in this study) in ischemic stroke.

RESULTS

CircPHC3 was highly expressed in human BMECs after OGD. Knockdown of circPHC3 inhibited cell death and apoptosis in human BMECs treated with OGD. Mechanistically, circPHC3 acted as miR-455-5p sponge to activate TRAF3 to promote cell death and apoptosis in human BMECs after OGD.

CONCLUSION

In short, circPHC3 promotes cell death and apoptosis in ischemic stroke in vitro model, which might be a novel molecular target for acute cerebrovascular protection.

PKA-Dependent Membrane Surface Recruitment of CI-AMPARs Is Crucial for BCP-Mediated Protection Against Post-acute Ischemic Stroke Cognitive Impairment

Post-acute ischemic stroke cognitive impairment frequently occurs and seriously affects patients daily activities. Recruitment of GluA2-containing Ca²⁺-impermeable AMPA receptors (CI-AMPARs) to hippocampal synaptic membrane surfaces was shown to trigger synaptic plasticity. Currently, the effect of CI-AMPAR trafficking on acute ischemic stroke remains poorly understood. β-Caryophyllene (BCP) has been shown to ameliorate cognitive impairment. However, the mechanism has not been characterized. In this study, a 60-min temporary middle cerebral artery occlusion (MCAO) model was established to simulate the pathology of acute ischemic stroke. BCP reduced neurologic deficits, cerebral infarct volume, and pathological damage in MCAO mice and caused CI-AMPARs to translocate to synaptic membranes in the hippocampus; surface expression of CI-AMPARs was also decreased in MCAO mice. Furthermore, this study also showed that BCP treatment significantly activated the cAMP/PKA pathway, which is consistent with the synaptic membrane expression of CI-AMPARs. To better understand the underlying mechanisms, the PKA inhibitor H-89 was used to study the role of BCP in MCAO mice. Interestingly, H-89 treatment significantly disrupted the BCP-mediated facilitation of CI-AMPAR translocation to the synaptic membrane surface and substantially attenuated BCP-induced protection against acute ischemic stroke. Additionally, inhibition the cAMP/PKA pathway not only reduced BCP-induced inhibition of AMPAR-mediated excitatory postsynaptic currents in the hippocampal CA1 region but also decreased the effect of BCP-mediated protection against post-acute ischemic stroke cognitive impairment. Taken together, these data indicate that PKA-dependent synaptic membrane surface recruitment of CI-AMPARs is crucial for the neuroprotective effect of BCP against acute ischemic stroke and protection against post-acute ischemic stroke cognitive impairment.

The impact of cannabinoid type 2 receptors (CB2Rs) in neuroprotection against neurological disorders

Cannabinoids have long been used for their psychotropic and possible medical properties of symptom relief. In the past few years, a vast literature shows that cannabinoids are neuroprotective under different pathological situations. Most of the effects of cannabinoids are mediated by the well-characterized cannabinoid receptors, the cannabinoid type 1 receptor (CB1R) and cannabinoid type 2 receptor (CB2R). Even though CB1Rs are highly expressed in the central nervous system (CNS), the adverse central side effects and the development of tolerance resulting from CB1R activation may ultimately limit the clinical utility of CB1R agonists. In contrast to the ubiquitous presence of CB1Rs, CB2Rs are less commonly expressed in the healthy CNS but highly upregulated in glial cells under neuropathological conditions. Experimental studies have provided robust evidence that CB2Rs seem to be involved in the modulation of different neurological disorders. In this paper, we summarize the current knowledge regarding the protective effects of CB2R activation against the development of neurological diseases and provide a perspective on the future of this field. A better understanding of the fundamental pharmacology of CB2R activation is essential for the development of clinical applications and the design of novel therapeutic strategies.

Downregulation of circular RNA HECTD1 induces neuroprotection against ischemic stroke through the microRNA-133b/TRAF3 pathway

AIMS

Circular RNAs (circRNAs) have been shown to play crucial roles in various biological processes and human diseases. However, their exact functions in ischemic stroke remain largely unknown. In this study, we explored the functional role of circRNA HECTD1 (circ-HECTD1) and its underlying mechanism in cerebral ischemia/reperfusion injury.

METHODS

Mouse middle cerebral artery occlusion (MCAO) model and oxygen-glucose deprivation (OGD) model in HT22 cells were used to mimic the cerebral ischemia/reperfusion injury. Brain infarct volume, flow cytometry, caspase 3 activity, NF-κB activity, and TUNEL staining were performed to evaluate the function of circ-HECTD1. Luciferase report assay was used to explore the regulatory mechanism.

FINDINGS

The results showed that the expression of circ-HECTD1 and tumor necrosis factor receptor-associated factor 3 (TRAF3) was remarkably up-regulated, while miR-133b was down-regulated in oxygen-glucose deprivation (OGD)-induced HT22 cells and mouse middle cerebral artery occlusion (MCAO) model. circ-HECTD1 knockdown relieved OGD-caused neuronal cell death in vitro. Simultaneously, circ-HECTD1 knockdown improved cerebral infarction volume and neuronal apoptosis in MCAO mice. circ-HECTD1 was able to negatively regulate the expression of miR-133b, and TRAF3 is one of the targets of miR-133b. Upregulation of miR-133b inhibited the expression of TRAF3 in OGD-stimulated cells, whereas circ-HECTD1 upregulation reversed this effect. Furthermore, upregulation of miR-133 was able to inhibit OGD-caused cell apoptosis and NF-κB activation, whereas upregulation of circ-HECTD1 attenuated these effects of miR-133b mimics.

SIGNIFICANCE

Taken together, circ-HECTD1 knockdown inhibited the expression of TRAF3 by targeting miR-133b, thereby attenuating neuronal injury caused by cerebral ischemia.

β-Caryophyllene Liposomes Attenuate Neurovascular Unit Damage After Subarachnoid Hemorrhage in Rats

This study was conducted to prepare β-caryophyllene loaded liposomes (BCP-LP) and investigated their effects on neurovascular unit (NVU) damage after subarachnoid hemorrhage (SAH) in rats. A blood injection into the pre-chiasmatic cistern was used to achieve SAH. BCP-LP were prepared, characterized and administrated to rats with SAH. The prepared BCP-LP were spherical with a size distribution of approximately 189.3 nm and Zeta potential of - 13.9 mV. Neurological scoring, the balance beam test, cerebral blood flow monitoring, brain edema and biochemical analyses were applied to evaluate the effects of BCP-LP on rat NVU damage after SAH. The results demonstrated that BCP-LP treatment improved neurological function disorder, balance ability and cerebral blood perfusion in rats. Brain edema detection and blood-brain barrier permeability detection revealed that BCP-LP could reduce brain edema and promote repairment of blood-brain barrier after SAH. Using the western blot experiments, we demonstrated that BCP-LP attenuated the loss of tight junction proteins Occludin and Zonula occludens-1, inhibit the high expression of VEGFR-2 and GFAP, and promote the repair of laminin. These results demonstrate the protective effect BCP-LP exert in the NVU after SAH in rats, and supports the use of BCP-LP for future study and therapy of SAH.

Effect of palmitoylethanolamide on inner retinal function in glaucoma: a randomized, single blind, crossover, clinical trial by pattern-electroretinogram

Glaucoma is a neurodegenerative disease, our study aimed to evaluate the potential effects of Palmitoylethanolamide (PEA) supplementation on RGCs function by PERG examination, and to record effects on intraocular pressure, visual field and quality of life. It was a single centre, randomized, prospective, single blind, two treatment, two period crossover study on stable glaucoma patients on topical monotherapy comparing current topical therapy alone or additioned with PEA 600 mg one tablet a day. At baseline, at 4 and at 8 months, all patients underwent to complete ophthalmic examination, pattern electroretinogram, visual field, and quality of life evaluation. 40 patients completed the study: mean age 66.6 ± 7.6 years; 21 (52.5%) male; 35 POAG (87.5%). At baseline, most patients had an early visual field defect, the IOP was well controlled. At the end of the PEA 600 mg supplementation, a significantly higher (mean 0.56 μV, 95% CI 0.30-0.73, p < 0.001) in the P50-wave amplitude was observed; in the PEA period a significantly lower IOP (- 1.6 mmHg, 95% CI - 2 to 1.2, p < 0.001) and higher quality of life scores (+ 6.7, 95% CI 4-9.9, p < 0.001) were observed. Our study is the first to show promising effects of PEA on PERG and on quality of life in glaucoma patients.

Cannabinoid type-2 receptor agonist, inverse agonist, and anandamide regulation of inflammatory responses in IL-1β stimulated primary human periodontal ligament fibroblasts

OBJECTIVE

The aim of this study is to understand the role of cannabinoid type 2 receptor (CB2R) during periodontal inflammation and to identify anti-inflammatory agents for the development of drugs to treat periodontitis (PD).

BACKGROUND

Cannabinoid type 2 receptor is found in periodontal tissue at sites of inflammation/infection. Our previous study demonstrated anti-inflammatory responses in human periodontal ligament fibroblasts (hPDLFs) via CB2R ligands.

METHODS

Anandamide (AEA), HU-308 (agonist), and SMM-189 (inverse agonist) were tested for effects on IL-1β-stimulated cytokines, chemokines, and angiogenic and vascular markers expressed by hPDLFs using Mesoscale Discovery V-Plex Kits. Signal transduction pathways (p-c-Jun, p-ERK, p-p-38, p-JNK, p-CREB, and p-NF-kB) were investigated using Cisbio HTRF kits. ACTOne and Tango™ -BLA functional assays were used to measure cyclic AMP (cAMP) and β-arrestin activity.

RESULTS

IL-1β stimulated hPDLF production of 18/39 analytes, which were downregulated by the CB2R agonist and the inverse agonist. AEA exhibited pro-inflammatory and anti-inflammatory effects. IL-1β increased phosphoproteins within the first hour except p-JNK. CB2R ligands attenuated p-p38 and p-NFĸB, but a late rise in p-38 was seen with HU-308. As p-ERK levels declined, a significant increase in p-ERK was observed later in the time course by synthetic CB2R ligands. P-JNK was significantly affected by SMM-189 only, while p-CREB was elevated significantly by CB2R ligands at 180 minutes. HU-308 affected both cAMP and β-arrestin pathway. SMM-189 only stimulated cAMP.

CONCLUSION

The findings that CB2R agonist and inverse agonist may potentially regulate inflammation suggest that development of CB2R therapeutics could improve on current treatments for PD and other oral inflammatory pathologies.

[Role of mitochondrial fusion and fission in protective effects of dexmedetomidine against cerebral ischemia/reperfusion injury in mice]

OBJECTIVE

To investigate the protective effects of dexmedetomidine (DEX) against cerebral ischemia/reperfusion (I/R) injury in mice and its relation with mitochondrial fusion and fission.

METHODS

Male ICR mice were randomly divided into sham-operated group, I/R group, I/R+DEX group and I/R+DEX+dorsomorphin group. Mouse models of cerebral I/R injury were established by modified thread occlusion of the middle cerebral artery. DEX (50 μg/kg) was injected intraperitoneally at 30 min before cerebral ischemia, which lasted for 1 h followed by reperfusion for 24 h. The neurobehavioral deficits of the mice were evaluated based on Longa's scores. The volume of cerebral infarction was detected by TTC staining. The changes in mitochondrial morphology of the brain cells were observed with transmission electron microscopy. Western blotting was performed to detect the expressions of phosphorylated AMP-activated protein kinase (p-AMPK), mitochondrial fusion protein (Mfn2) and mitochondrial fission protein (p-Drp1) in the brain tissues.

RESULTS

DEX pretreatment significantly reduced the neurobehavioral score and the percent volume of cerebral infarction in mice with cerebral I/R injury. Treatment with dorsomorphin (an AMPK inhibitor) in addition to DEX significantly increased the neurobehavioral score and the percent volume of cerebral infarction in the mouse models. Transmission electron microscopy showed that DEX obviously reduced mitochondrial damage caused by cerebral I/R injury and restored mitochondrial morphology of the brain cells, and such effects were abolished by dorsomorphin treatment. Western blotting showed that DEX pretreatment significantly increased the expressions of p-AMPK and Mfn2 protein and decreased the expression of p-Drp1 protein in the brain tissue of the mice, and these changes were also reversed by dorsomorphin treatment.

CONCLUSIONS

Preconditioning with DEX produces protective effects against cerebral I/R injury in mice possibly by activating AMPK signaling to regulate mitochondrial fusion and fission in the brain cells.

Interaction of Cannabis Use and Aging: From Molecule to Mind

Given the aging Baby Boomer generation, changes in cannabis legislation, and the growing acknowledgment of cannabis for its therapeutic potential, it is predicted that cannabis use in the older population will escalate. It is, therefore, important to determine the interaction between the effects of cannabis and aging. The aim of this report is to describe the link between cannabis use and the aging brain. Our review of the literature found few and inconsistent empirical studies that directly address the impact of cannabis use on the aging brain. However, research focused on long-term cannabis use points toward cumulative effects on multimodal systems in the brain that are similarly affected during aging. Specifically, the effects of cannabis and aging converge on overlapping networks in the endocannabinoid, opioid, and dopamine systems that may affect functional decline particularly in the hippocampus and prefrontal cortex, which are critical areas for memory and executive functioning. To conclude, despite the limited current knowledge on the potential interactive effects between cannabis and aging, evidence from the literature suggests that cannabis and aging effects are concurrently present across several neurotransmitter systems. There is a great need for future research to directly test the interactions between cannabis and aging.

Anti-inflammatory Property of AMP-activated Protein Kinase

BACKGROUND

One of the many debated topics in inflammation research is whether this scenario is really an accelerated form of human wound healing and immunityboosting or a push towards autoimmune diseases. The answer requires a better understanding of the normal inflammatory process, including the molecular pathology underlying the possible outcomes. Exciting recent investigations regarding severe human inflammatory disorders and autoimmune conditions have implicated molecular changes that are also linked to normal immunity, such as triggering factors, switching on and off, the influence of other diseases and faulty stem cell homeostasis, in disease progression and development.

METHODS

We gathered around and collected recent online researches on immunity, inflammation, inflammatory disorders and AMPK. We basically searched PubMed, Scopus and Google Scholar to assemble the studies which were published since 2010.

RESULTS

Our findings suggested that inflammation and related disorders are on the verge and interfere in the treatment of other diseases. AMPK serves as a key component that prevents various kinds of inflammatory signaling. In addition, our table and hypothetical figures may open a new door in inflammation research, which could be a greater therapeutic target for controlling diabetes, obesity, insulin resistance and preventing autoimmune diseases.

CONCLUSION

The relationship between immunity and inflammation becomes easily apparent. Yet, the essence of inflammation turns out to be so startling that the theory may not be instantly established and many possible arguments are raised for its clearance. However, this study might be able to reveal some possible approaches where AMPK can reduce or prevent inflammatory disorders.

CB2R orchestrates neuronal autophagy through regulation of the mTOR signaling pathway in the hippocampus of developing rats with status epilepticus

Neuronal loss and gliosis are the major pathological changes after status epilepticus (SE). The authors' previous study revealed the time-dependent changes of cannabinoid receptor type 2 (CB2R) in hippocampal neurons of developing rats after SE, which were accompanied by a decrease in the number of neurons. Meanwhile, growing evidence indicates that CB2R stimulation exerts anti-convulsant properties in seizure models. However, the activation of CB2R in neuronal repair in response to the damage after SE is still unclear. In this experiment, a highly-selective CB2R agonist JWH133 and antagonist AM630 were administered to determine the activity of CB2R in neuronal autophagy and apoptosis of the post-SE repair in developing rats. The present results revealed that activation of CB2R by JWH133, not only obviously lowered the success rate, 24-h death rate and the Racine stage in the model, but also extended the latency period to SE. In addition, compared with the vehicle control group, CB2R activation increased neuronal autophagy and the expression of phosphorylated-mammalian target of rapamycin (p-mTOR)/mTOR, Beclin-1, and LC3II/LC3I while decreasing the expression of p-Unc-51-like autophagy-activating kinase 1 (ULK-1)/ULK1, p62, and cleaved caspase-3. These results were dose-dependent and were especially evident in the high-dose group, and interestingly the opposite results were obtained in the AM630 group. Thus, CB2R orchestrates neuronal autophagy through regulation of the mTOR signaling pathway in the hippocampus of developing rats with SE. These findings might provide an important basis for further investigation of the therapeutic role of CB2R in ameliorating epilepsy-related neuronal damage.