Tag Archives: cannabinoid receptors

Cannabinoid receptor 2 augments eosinophil responsiveness and aggravates allergen-induced pulmonary inflammation in mice.

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“Accumulation of activated eosinophils in tissue is a hallmark of allergic inflammation.

The endocannabinoid 2-arachidonoylglycerol (2-AG) has been proposed to elicit eosinophil migration in a CB2 receptor/Gi/o -dependent manner.

Here we explored the direct contribution of specific CB2 receptor activation to human and mouse eosinophil effector function in vitro and in vivo.

Our data indicate that CB2 may directly contribute to the pathogenesis of eosinophil-driven diseases. Moreover, we provide new insights into the molecular mechanisms underlying the CB2 -mediated priming of eosinophils. Hence, antagonism of CB2 receptors may represent a novel pharmacological approach for the treatment of allergic inflammation and other eosinophilic disorders.”

http://www.ncbi.nlm.nih.gov/pubmed/26850094

A systematic review of plant-derived natural compounds for anxiety disorders.

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“Anxiety disorders are the most common mental illnesses affecting human beings. They range from panic to generalized anxiety disorders upsetting the well-being and psychosocial performance of patients. Several conventional anxiolytic drugs are being used which in turn result in several adverse effects. Therefore, studies to find suitable safe medicines from natural sources are being conducted by researchers.

The aim of the present study is to comprehensively review phytochemical compounds with well-established anxiolytic activities and their structure-activity relationships as well as neuropsychopharmacological aspects. Results showed that phytochemicals like; alkaloids, flavonoids, phenolic acids, lignans, cinnamates, terpenes and saponins possess anxiolytic effects in a wide range of animal models of anxiety.

The involved mechanisms include interaction with γ-aminobutyric acid (GABA)A receptors at benzodiazepine (BZD) and non-BZD sites with various affinity to different subunits, serotonergic 5-hydrodytryptamine (5-HT)1A and 5-HT2A/C receptors, noradrenergic and dopaminergic systems, glycine and glutamate receptors, and κ-opioid receptor as well as cannabinoid (CB)1 and CB2 receptors.

Phytochemicals also modulate the hypothalamo-pituitary-adrenal (HPA) axis, the levels of pro-inflammatory cytokines like interleukin (IL)-2, IL-6, IL-1β and tumor necrosis factor (TNF)-α, and improve brain derived neurotrophic factor (BDNF) levels. Transient receptor potential cation channel subfamily V (TRPV)3, nitric oxide cyclic guanosine monophosphate (NO-cGMP) pathway and monoamine oxidase enzymes are other targets of phytochemicals with anxiolytic activity.

Taking together, these phytochemicals may be considered as supplements to conventional anxiolytic therapies in order to improve efficacy and reduce adverse effects.

Further preclinical and clinical studies are still needed in order to recognize the structure-activity relationships, metabolism, absorption, and neuropsychopharmacological mechanisms of plant-derived natural agents.”

http://www.ncbi.nlm.nih.gov/pubmed/26845556

The Cannabinoid CB1/CB2 Agonist WIN55212.2 Promotes Oligodendrocyte Differentiation In Vitro and Neuroprotection During the Cuprizone-Induced Central Nervous System Demyelination.

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“Different types of insults to the CNS lead to axon demyelination. Remyelination occurs when the CNS attempts to recover from myelin loss and requires the activation of oligodendrocyte precursor cells.

With the rationale that CB1 receptor is expressed in oligodendrocytes and marijuana consumption alters CNS myelination, we study the effects of the cannabinoid agonist WIN55212.2 in (1) an in vitro model of oligodendrocyte differentiation and (2) the cuprizone model for demyelination.

The cannabinoid agonist WIN55212.2 promotes oligodendrocyte differentiation in vitro.

Moreover, 0.5 mg/kg of the drug confers neuroprotection during cuprizone-induced demyelination, while 1 mg/kg aggravates the demyelination process.”

http://www.ncbi.nlm.nih.gov/pubmed/26842941

JWH-133, a Selective Cannabinoid CB2 Receptor Agonist, Exerts Toxic Effects on Neuroblastoma SH-SY5Y Cells.

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“Endocannabinoid system plays an important role in the regulation of diverse physiological functions.

Although cannabinoid type 2 receptors (CB2) are involved in the modulation of immune system in peripheral tissues, recent findings demonstrated that they are also expressed in the central nervous system and could constitute a new target for the treatment of neurodegenerative disorders.”

http://www.ncbi.nlm.nih.gov/pubmed/26842917

Simultaneous Activation of Induced Heterodimerization between CXCR4 Chemokine Receptor and Cannabinoid Receptor 2 (CB2) Reveal a Mechanism for Regulation of Tumor Progression.

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“The G-protein-coupled chemokine receptor, CXCR4, generates signals that lead to cell migration, cell proliferation, and other survival mechanisms which result in the metastatic spread of primary tumor cells to distal organs.

Numerous studies have demonstrated that CXCR4 can form homodimers, or can heterodimerize with other GPCRs to form receptor complexes that can amplify or decrease the signaling capacity of each individual receptor.

Using biophysical and biochemical approaches, we found that CXCR4 can form an induced heterodimer with cannabinoid receptor 2 (CB2) in human breast and prostate cancer cells.

Simultaneous, agonist-dependent activation of CXCR4 and CB2 resulted in reduced CXCR4-mediated expression of phosphorylated ERK1/2, and ultimately, reduced cancer cell functions such as calcium mobilization and cellular chemotaxis.

Given that treatment with cannabinoids has been shown to reduce invasiveness of cancer cells, as well as CXCR4-mediated migration of immune cells, it is therefore plausible that CXCR4 signaling can be silenced through a physical heterodimeric association with CB2, thereby inhibiting subsequent functions of CXCR4.

Taken together, the data illustrates a mechanism by which the cannabinoid system can negatively modulate CXCR4 receptor function, and perhaps, tumor progression.”

http://www.ncbi.nlm.nih.gov/pubmed/26841863

Expression and Function of the Endocannabinoid System in the Retina and the Visual Brain.

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“Endocannabinoids are important retrograde modulators of synaptic transmission throughout the nervous system.

Cannabinoid receptors are seven transmembrane G-protein coupled receptors favoring Gi/o protein. They are known to play an important role in various processes, including metabolic regulation, craving, pain, anxiety, and immune function.

In the last decade, there has been a growing interest for endocannabinoids in the retina and their role in visual processing.

The purpose of this review is to characterize the expression and physiological functions of the endocannabinoid system in the visual system, from the retina to the primary visual cortex, with a main interest regarding the retina, which is the best-described area in this system so far.

It will show that the endocannabinoid system is widely present in the retina, mostly in the through pathway where it can modulate neurotransmitter release and ion channel activity, although some evidence also indicates possible mechanisms via amacrine, horizontal, and Müller cells.

The presence of multiple endocannabinoid ligands, synthesizing and catabolizing enzymes, and receptors highlights various pharmacological targets for novel therapeutic application to retinal diseases.”

http://www.ncbi.nlm.nih.gov/pubmed/26839718

The molecular mechanism and effect of cannabinoid-2 receptor agonist on the blood-spinal cord barrier permeability induced by ischemia-reperfusion injury.

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“Previous studies have shown that modulation of the receptor-mediated endocannabinoid system during ischemia injury can induce potent neuroprotective effects.

However, little is known about whether cannabinoid-2 (CB2) receptor agonist would produce a protective effect on blood-spinal cord barrier (BSCB) during ischemia.

Taken together, all of these results suggested that JWH-015 might regulate the BSCB permeability and this effect could be related to paracellular and transcellular pathway.

And pharmacological CB2R ligands offer a new strategy for BSCB protection during ischemic injury.”

http://www.ncbi.nlm.nih.gov/pubmed/26835555

Regulation of Stem Cells by the Endocannabinoid System

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“The endocannabinoids, endogenous lipid mediators of related chemical structure to the prototype exogenous cannabinoid Δ9-THC found in marijuana, have emerged as important mediators that regulate central and peripheral neural functions as well as immune responses.

Endogenous and exogenous cannabinoid ligands bind to cannabinoid receptors: the predominant central cannabinoid receptor type 1 (CB1) and the peripheral cannabinoid receptor type 2 (CB2). CB1 and CB2 are members of the G-protein coupled receptor family.

Cannabinoids were shown to modulate the immune system and to affect the migration of blood cells, such as T-cells, monocytes and myeloid leukemia cells, through CB receptors.

Recent data indicate the potential role of cannabinoid ligands and receptors in the regulation of hematopoiesis and hematopoietic stem cell (HSC) migration and trafficking.

These studies may lead to clinical applications of cannabinoid-based compounds as new HSC-mobilizer agents for therapeutic intervention in bone marrow failure.”

http://link.springer.com/chapter/10.1007/978-94-007-2993-3_30

Cannabinoid receptor signaling in progenitor/stem cell proliferation and differentiation.

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“Cannabinoids, the active components of cannabis (Cannabis sativa) extracts, have attracted the attention of human civilizations for centuries, much earlier than the discovery and characterization of their substrate of action, the endocannabinoid system (ECS).

The latter is an ensemble of endogenous lipids, their receptors [in particular type-1 (CB1) and type-2 (CB2) cannabinoid receptors] and metabolic enzymes.

Cannabinoid signaling regulates cell proliferation, differentiation and survival, with different outcomes depending on the molecular targets and cellular context involved.

Cannabinoid receptors are expressed and functional from the very early developmental stages, when they regulate embryonic and trophoblast stem cell survival and differentiation, and thus may affect the formation of manifold adult specialized tissues derived from the three different germ layers (ectoderm, mesoderm and endoderm).

In the ectoderm-derived nervous system, both CB1 and CB2 receptors are present in neural progenitor/stem cells and control their self-renewal, proliferation and differentiation. CB1 and CB2 show opposite patterns of expression, the former increasing and the latter decreasing along neuronal differentiation.

Recently, endocannabinoid (eCB) signaling has also been shown to regulate proliferation and differentiation of mesoderm-derived hematopoietic and mesenchymal stem cells, with a key role in determining the formation of several cell types in peripheral tissues, including blood cells, adipocytes, osteoblasts/osteoclasts and epithelial cells.

Here, we will review these new findings, which unveil the involvement of eCB signaling in the regulation of progenitor/stem cell fate in the nervous system and in the periphery.

The developmental regulation of cannabinoid receptor expression and cellular/subcellular localization, together with their role in progenitor/stem cell biology, may have important implications in human health and disease.”

http://www.ncbi.nlm.nih.gov/pubmed/24076098

CB2 cannabinoid receptors promote mouse neural stem cell proliferation.

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“Neurospheres are clonal cellular aggregates of neural stem/precursor cells that grow in culture as free-floating clusters. Activation of CB1 cannabinoid receptors, which are expressed by these cells, promotes proliferation.

In the present study we investigated the expression of CB2 cannabinoid receptors and the effect of exogenous cannabinoids on neural stem/precursor cell proliferation.

Neurospheres containing nestin-positive and sn-1 diacylglycerol lipase alpha-positive cells expressed both CB1 and CB2 receptors, which were maintained through several passages…

Together, our results suggest that cannabinoids stimulate proliferation of neural stem/precursor cells acting on both CB1 and CB2 cannabinoid receptors through a phosphoinositide-3 kinase/Akt pathway.”

http://www.ncbi.nlm.nih.gov/pubmed/17328768