Tag Archives: CB(1) and CB(2) receptors

Long-term cannabinoid type 2 receptor agonist therapy decreases Bacterial Translocation In Rats with cirrhosis and ascites.

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“Intestinal hyper-permeability, impaired peritoneal macrophages (PMs) phagocytosis, and, bacterial translocation (BT) resulting in increased systemic and local infection/inflammation such as spontaneous bacterial peritonitis (SBP), together with increased tumor necrosis factor-α (TNFα) levels, are all implicated in the pathogenesis of cirrhosis-related complications.

Manipulation of cannabinoid receptors (CB1R and CB2R), which are expressed on the gut mucosa and PMs, has been reported to modulate intestinal inflammation and systemic inflammatory cytokines release. Our study aims to explore the effects of chronic CB1R/CB2R agonist/antagonist treatments on relevant abnormalities in cirrhotic ascitic rats…

CONCLUSIONS:

Our study suggests that CB2R agonist have the potential to treat BT and various relevant abnormalities through the inhibition of systemic/intestinal oxidative stress, inflammatory cytokines and TNFα releases in cirrhosis. Overall, chronic CB2R agonist treatment affects multiple approach mechanisms, and the direct effect on hyperdynamic circulation is only minor.”

http://www.ncbi.nlm.nih.gov/pubmed/24953022

Role of Endocannabinoid Activation of Peripheral CB1 Receptors in the Regulation of Autoimmune Disease.

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“The impact of the endogenous cannabinoids (AEA, 2-AG, PEA, and virodamine) on the immune cell expressed cannabinoid receptors (CB1, CB2, TRPV-1, and GPR55) and consequent regulation of immune function is an exciting area of research with potential implications in the prevention and treatment of inflammatory and autoimmune diseases.

Despite significant advances in understanding the mechanisms through which cannabinoids regulate immune functions, not much is known about the role of endocannabinoids in the pathogenesis or prevention of autoimmune diseases.

Inasmuch as CB2 expression on immune cells and its role has been widely reported, the importance of CB1 in immunological disorders has often been overlooked especially because it is not highly expressed on naive immune cells.

Therefore, the current review aims at delineating the effect of endocannabinoids on CB1 receptors in T cell driven autoimmune diseases. This review will also highlight some autoimmune diseases in which there is evidence indicating a role for endocannabinoids in the regulation of autoimmune pathogenesis.

Overall, based on the evidence presented using the endocannabinoids, specifically AEA, we propose that the peripheral CB1 receptor is involved in the regulation and amelioration of inflammation associated with autoimmune diseases.”

http://www.ncbi.nlm.nih.gov/pubmed/24911431

Cannabinoid receptor 2: potential role in immunomodulation and neuroinflammation.

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Figure 2

“The cannabinoids are a group of terpenophenolic compounds present in the marijuana plant, Cannabis sativa. At present, three general types of cannabinoids have been identified: phytocannabinoids present uniquely in the cannabis plant, endogenous cannabinoids produced in humans and animals, and synthetic cannabinoids generated in a laboratory. It is worth noting that Cannabis sativa produces over 80 cannabinoids…

An accumulating body of evidence suggests that endocannabinoids and cannabinoid receptors type 1 and 2 (CB(1), CB(2)) play a significant role in physiologic and pathologic processes, including cognitive and immune functions.

…there is growing appreciation of the therapeutic potential of cannabinoids in multiple pathologic conditions involving chronic inflammation (inflammatory bowel disease, arthritis, autoimmune disorders, multiple sclerosis, HIV-1 infection, stroke, Alzheimer’sdisease to name a few), mainly mediated by CB(2) activation.

This review attempts to summarize recent advances in studies of CB(2) activation in the setting of neuroinflammation, immunomodulation and HIV-1 infection.

The full potential of CB2 agonists as therapeutic agents remains to be realized.

Despite some inadequacies of preclinical models to predict clinical efficacy in humans and differences between the signaling of human and rodent CB2 receptors, the development of selective CB2 agonists may open new avenues in therapeutic intervention.

Such interventions would aim at reducing the release of pro-inflammatory mediators particularly in chronic neuropathologic conditions such as HAND or MS.”

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3663904/

 

Cannabinoid Receptor Type 1- and 2-mediated Increase in Cyclic AMP Inhibits T Cell Receptor-triggered Signaling

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FIGURE 1.

“The aim of this study was to characterize inhibitory mechanisms on T cell receptor signaling mediated by the cannabinoid receptors CB1 and CB2. Both receptors are coupled to G(i/o) proteins, which are associated with inhibition of cyclic AMP formation…

These findings help to better understand the immunosuppressive effects of cannabinoids and explain the beneficial effects of these drugs in the treatment of T cell-mediated autoimmune disorders like multiple sclerosis.

To sum up, our results help to explain immunosuppressive effect of cannabinoid drugs, which may be important for the pharmacological evaluation of these drugs, e.g. with respect to their use in neuroinflammatory diseases and T cell-mediated autoimmune disorders like multiple sclerosis.”

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2790974/#!po=45.6522

Activation through cannabinoid receptors 1 and 2 on dendritic cells triggers NF-kappaB-dependent apoptosis: novel role for endogenous and exogenous cannabinoids in immunoregulation.

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<br /> FIGURE 1.<br />

“Cannabinoids are compounds derived from the Cannabis sativa (marijuana) plant, as well as produced endogenously in the brain and by immune cells. Cannabinoids mediate their effect through cannabinoid receptors (CB), designated CB1 and CB2, which belong to a superfamily of G-protein-coupled receptors.

CB1 receptors are expressed at high levels in CNS, where they regulate psychoactivity. CB1 receptors are also expressed on immune cells. In contrast, the CB2 receptors are primarily expressed on immune cells and do not contribute to the psychoactivity. The presence of endogenous CB-ligand systems in immune cells suggests that they may play a critical physiological role, the precise nature of which remains to be characterized.

Cannabinoids can decrease the immune response… Cannabinoids have also been widely used in the treatment of pain and inflammation.

Moreover, preliminary studies have shown the possible use of cannabinoids in the treatment of autoimmune diseases such as multiple sclerosis.

Recent studies from our lab demonstrated that Δ9-tetrahydrocannabinol (THC) can trigger apoptosis in vivo in thymocytes and splenocytes, which may account for immunosuppression.

 We demonstrate for the first time that THC and endocannabinoids such as anandamide can induce apoptosis in DCs through activation of CB1 and CB2 receptors.

These studies provide the basis for understanding the mechanism by which THC triggers immunosuppression and mediates anti-inflammatory properties.

Many studies have suggested the use of THC or related cannabinoids in the treatment of autoimmune diseases.”

http://www.jimmunol.org/content/173/4/2373.long

CB2 cannabinoid receptor agonist, JWH-015, triggers apoptosis in immune cells: potential role for CB2-selective ligands as immunosuppressive agents.

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“Marijuana has been used for recreational and medicinal purposes for centuries. Its medicinal use can be traced back to ancient Chinese and Egyptian civilizations…

Cannabinoids are known to interact with CB1 and CB2 receptors expressed in the nervous and immune system, respectively, and mediate a wide range of effects, including anti-inflammatory properties…

The current study suggests that targeting CB2 receptors may constitute a unique treatment modality against inflammatory diseases…

Together, this study suggests that CB2-selective agonists, devoid of psychotropic effect, may serve as novel anti-inflammatory/immunosuppressive agents.”

 http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1864948/

Cannabinoid-induced apoptosis in immune cells as a pathway to immunosuppression.

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Fig. 1

“Cannabinoids are a group of compounds found in the marijuana plant (Cannabis sativaL.). Marijuana has been used both for recreational and medicinal purposes for several centuries.

Cannabinoids have been shown to be effective in the treatment of nausea and vomiting associated with cancer chemotherapy, anorexia and cachexia seen in HIV/AIDS patients, as well as neuropathic pain, and spasticity in multiple sclerosis.

More recently, the anti-inflammatory properties of cannabinoids are drawing significant attention. In the last 15 years, studies with marijuana cannabinoids led to the discovery of cannabinoid receptors (CB1 and CB2) and their endogenous ligands, which make up what is known as the endocannabinoid system.

Cannabinoids are a group of compounds present in Cannabis plant (Cannabis sativa L.). They mediate their physiological and behavioral effects by activating specific cannabinoid receptors. With the recent discovery of the cannabinoid receptors (CB1 and CB2) and the endocannabinoid system, research in this field has expanded exponentially.

Cannabinoids have been shown to act as potent immunosuppressive and anti-inflammatory agents and have been shown to mediate beneficial effects in a wide range of immune-mediated diseases such as multiple sclerosis, diabetes, septic shock, rheumatoid arthritis, and allergic asthma.

Cannabinoid receptor 1 (CB1) is mainly expressed on the cells of the central nervous system as well as in the periphery. In contrast, cannabinoid receptor 2 (CB2) is predominantly expressed on immune cells. The precise mechanisms through which cannabinoids mediate immunosuppression is only now beginning to be understood…

In this review, we will focus on apoptotic mechanisms of immunosuppression mediated by cannabinoids on different immune cell populations and discuss how activation of CB2 provides a novel therapeutic modality against inflammatory and autoimmune diseases as well as malignancies of the immune system, without exerting the untoward psychotropic effects…

…cannabinoids do induce apoptosis in immune cells, alleviating inflammatory responses and protecting the host from acute and chronic inflammation.

The cumulative effect of cannabinoids on all cell populations of the immune system can be beneficial, when there is a need for immune suppression.

For example, in patients with autoimmune diseases such as multiple sclerosis, arthritis and lupus, or in those with septic shock, where the disease is caused by activated immune cells, targeting the immune cells via CB2 agonists may trigger apoptosis and act as anti-inflammatory therapy.

CB2 select agonists are not psychoactive and because CB2 is expressed primarily in immune cells, use of CB2 agonists could provide a novel therapeutic modality against autoimmune and inflammatory diseases.

In addition to the use of exogenous cannabinoids, in vivo manipulation of endocannabinoids may also offer novel treatment opportunities against cancer and autoimmune diseases.”

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3005548/

Direct suppression of CNS autoimmune inflammation via the cannabinoid receptor CB1 on neurons and CB2 on autoreactive T cells.

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“The cannabinoid system is immunomodulatory and has been targeted as a treatment for the central nervous system (CNS) autoimmune disease multiple sclerosis.

Using an animal model of multiple sclerosis, experimental autoimmune encephalomyelitis (EAE), we investigated the role of the CB(1) and CB(2) cannabinoid receptors in regulating CNS autoimmunity…

Together, our results demonstrate that the cannabinoid system within the CNS plays a critical role in regulating autoimmune inflammation, with the CNS directly suppressing T-cell effector function via the CB(2) receptor.”

http://www.ncbi.nlm.nih.gov/pubmed/17401376

CB2 cannabinoid receptors as an emerging target for demyelinating diseases: from neuroimmune interactions to cell replacement strategies

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Figure 2

“Amongst the various demyelinating diseases that affect the central nervous system, those induced by an inflammatory response stand out because of their epidemiological relevance. The best known inflammatory-induced demyelinating disease is multiple sclerosis, but the immune response is a common pathogenic mechanism in many other less common pathologies (e.g., acute disseminated encephalomyelitis and acute necrotizing haemorrhagic encephalomyelitis).

In all such cases, modulation of the immune response seems to be a logical therapeutic approach.

Cannabinoids are well known immunomodulatory molecules that act through CB1 and CB2 receptors. While activation of CB1 receptors has a psychotropic effect, activation of CB2 receptors alone does not. Therefore, to bypass the ethical problems that could result from the treatment of inflammation with psychotropic molecules, considerable effort is being made to study the potential therapeutic value of activating CB2 receptors.

In this review we examine the current knowledge and understanding of the utility of cannabinoids as therapeutic molecules for inflammatory-mediated demyelinating pathologies. Moreover, we discuss how CB2 receptor activation is related to the modulation of immunopathogenic states.

The activation of CB2receptors results in the modulation of the inflammatory response, restraining one of the agents responsible for the progress of demyelination and neuronal death, the ultimate causes of the symptoms in pathologies such as MS and EAE.

The modulation of inflammatory molecules through CB2 receptors could also enhance remyelination, stimulating the survival of oligodendrocyte precursors and neural stem/precursor cells, and their development into mature oligodendrocytes.

…this raises the possibility that CB2 agonists could have the potential to promote brain repair.”

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2219542/#!po=48.0769

Common polymorphism in the cannabinoid type 1 receptor gene (CNR1) is associated with microvascular complications in type 2 diabetes.

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“Endocannabinoids exert their biological effects via interaction with G-protein coupled cannabinoid receptors CB1 and CB2. Polymorphisms in the CNR1 gene (encoding CB1 receptor) were previously found to be associated with dyslipidemia and cardiovascular diseases. We investigated a role of the polymorphism in CNR1 gene in type 2 diabetes and its complications…

The novel finding of our study is the association of the G1359A polymorphism with diabetic nephropathy and diabetic retinopathy in patients with T2DM. This polymorphism was also associated with cardiovascular disease in the patient group.”

http://www.ncbi.nlm.nih.gov/pubmed/24075694