Cannabinoid receptor 2: potential role in immunomodulation and neuroinflammation.

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/

 

Tumor Necrosis Factor activation of vagal afferent terminal calcium is blocked by cannabinoids

Figure 4

“The early proinflammatory cytokine tumor necrosis factor (TNF) is released in significant quantities by the activated immune system in response to infection, leukemia, autoimmune disorders, and radiation sickness. Nausea, emesis, and anorexia are common features of these disorders. TNF action on vagal afferent terminals in the brainstem is a likely cause of the malaise associated with these disorders.

For millennia, cannabinoids(CB) have been used to combat the visceral malaise associated with chronic disease…

These results help to explain the effectiveness of cannabinoids in blocking the malaise generated by TNF-releasing disease processes by opposing effects on ryanodine channels.

We believe that this is the first demonstration of the likely intracellular mechanism used by CB1 analogs to block the effects of TNF on neurotransmitter mechanisms that cause pain and visceral malaise.

These results may explain how cannabinoids can be effective in the treatment of the allodynia and visceral malaise of chronic disease.”

 http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3342927/

Attenuation of experimental autoimmune hepatitis by exogenous and endogenous cannabinoids: involvement of regulatory T cells.

Fig. 1

“Immune-mediated liver diseases including autoimmune and viral hepatitis are a major health problem worldwide. Natural cannabinoids such as Delta(9)-tetrahydrocannabinol (THC) effectively modulate immune cell function, and they have shown therapeutic potential in treating inflammatory diseases.

We investigated the effects of THC in a murine model of concanavalin A (ConA)-induced hepatitis…

Our data demonstrate that targeting cannabinoid receptors using exogenous or endogenous cannabinoids and use of FAAH inhibitors may constitute novel therapeutic modalities to treat immune-mediated liver inflammation.

δ-9-Tetrahydrocannabinol (THC), the major psychoactive component of marijuana (Cannabis sativa), has wide-ranging pharmacological properties. The cannabinoid compounds possess significant immunosuppressive and anti-inflammatory properties. THC and cannabinoid receptor agonists have shown promise in several models of inflammation.”

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2828293/

Role of Myeloid-Derived Suppressor Cells in Amelioration of Experimental Autoimmune Hepatitis Following Activation of TRPV1 Receptors by Cannabidiol

Figure 1

“Myeloid-derived suppressor cells (MDSCs) are getting increased attention as one of the main regulatory cells of the immune system. They are induced at sites of inflammation and can potently suppress T cell functions. In the current study, we demonstrate how activation of TRPV1 vanilloid receptors can trigger MDSCs, which in turn, can inhibit inflammation and hepatitis…

This study demonstrates for the first time that MDSCs play a critical role in attenuating acute inflammation in the liver, and that agents such as CBD, which trigger MDSCs through activation of TRPV1 vanilloid receptors may constitute a novel therapeutic modality to treat inflammatory diseases.

Cannabidiol (CBD) is a major non-psychoactive cannabinoid component of marijuana.

Together, these studies not only demonstrate that CBD can protect the host from acute liver injury but also provide evidence for the first time that MDSCs may play a critical role in protecting the liver from acute inflammation.

Non-psychoactive cannabinoids such as CBD possess great therapeutic potential in treating various inflammatory liver diseases, including autoimmune hepatitis.”

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3069975/

Targeting the cannabinoid pathway limits the development of fibrosis and autoimmunity in a mouse model of systemic sclerosis.

Figure 1

“Our aim was to evaluate the roles of the cannabinoid pathway in the induction and propagation of systemic sclerosis (SSc) in a mouse model…

Experiments performed in CB2-deficient mice confirmed the influence of CB2 in the development of systemic fibrosis and autoimmunity. Therefore, we demonstrate that the CB2 receptor is a potential target for the treatment of SSc because it controls both skin fibroblast proliferation and the autoimmune reaction.

In this report, we demonstrate for the first time the highly protective role of cannabinoid agonists in SSc. Because these agonists are available and well-tolerated under clinical conditions, our data offer a new therapeutic opportunity in this life-threatening disease.

In conclusion, modulation of the endocannabinoid system is a novel approach for the treatment of various inflammatory diseases.”

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2893662/

Immunoactive effects of cannabinoids: considerations for the therapeutic use of cannabinoid receptor agonists and antagonists

Figure 1

“The active constituents of Cannabis sativa have been used for centuries as recreational drugs and medicinal agents. Today, marijuana is the most prevalent drug of abuse in the United States and, conversely, therapeutic use of marijuana constituents are gaining mainstream clinical and political acceptance.

Given the documented contributions of endocannabinoid signaling to a range of physiological systems, including cognitive function, and the control of eating behaviors, it is unsurprising that cannabinoid receptor agonists and antagonists are showing significant clinical potential.

In addition to the neuroactive effects of cannabinoids, an emerging body of data suggests that both endogenous and exogenous cannabinoids are potently immunoactive.

The central premise of this review article is that the immunological effects of cannabinoids should be considered in the context of each prescribing decision.

We present evidence that the immunological effects of cannabinoid receptor agonists and antagonists are highly relevant to the spectrum of disorders for which cannabinoid therapeutics are currently offered.

Therapeutically relevant cannabinoid receptor ligands include tetra-hydrocannabinol itself, its synthetic forms, and its closely related compounds.

As a final point, the application of CB1 antagonists may be immunostimulative…”

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3804300/

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

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

Targeting the CB2 receptor for immune modulation.

“Early work on the biology of the components of Cannabis sativa showed evidence for a potential influence on immune regulation.

With the discovery of a peripheral cannabinoid receptor associated with immune cells, many laboratories have sought to link the immunoregulatory activities of cannabinoid compounds with this receptor, hoping that such compounds would lack the psychoactive effects of marijuana and other nonspecific cannabinoid agonists.

In this report, the authors investigate the role of the cannabinoid CB2 receptor in immune regulation, with particular emphasis on compounds shown to regulate immune cell recruitment.

The authors conclude by using the immune cell recruitment model to rationalise cannabinoidCB2 receptor-specific effects in modulating immune disease, particularly the increasing evidence for its role in experimental autoimmuneencephalomyelitis and in influencing bone density.”

http://www.ncbi.nlm.nih.gov/pubmed/16981823

Updating the chemistry and biology of cannabinoid CB2 receptor-specific inverse agonists.

“The cannabinoid CB(2) receptor continues to be an intriguing target for the potential therapeutic benefit of cannabinoids. Because this receptor is significantly found outside the brain, compounds specific for the CB(2) receptor may be free of the side effects that have plagued cannabinoid CB(1) receptor-based therapeutics.

In this review, we will discuss a class of compounds which modulate the constitutive activity of the cannabinoid CB(2) receptor, the inverse agonists. We will discuss recent chemical advances that provide new compounds to investigate the biology based on this pharmacology. We will then discuss new biology associated with the cannabinoid CB(2) receptor for hints of how these compounds can best be utilized in vivo.”

http://www.ncbi.nlm.nih.gov/pubmed/20370714

Biology and therapeutic potential of cannabinoid CB2 receptor inverse agonists

Figure 2

“Evidence has emerged suggesting a role for the cannabinoid CB2 receptor in immune cell motility. This provides a rationale for a novel and generalized immunoregulatory role for cannabinoid CB2 receptor-specific compounds…

An ability to control the migration of inflammatory cells to the site of insult is a powerful strategy for the development of immunomodulators. Our work on triaryl bis-sulphones suggest that the cannabinoid CB2 receptor-specific inverse agonists may serve as such immune modulators…

Further studies, using these and other CB2 receptor-specific compounds, will be required to resolve the complex pharmacology of cannabinoids and the cannabinoid CB2 receptor, and to determine the most effective pharmacology to exploit this therapeutic target.”

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2219522/