The endocannabinoid system modulates stress, emotionality, and inflammation.

“The physiological and behavioral effects of stress are well characterized.

Endocannabinoids are produced on demand and function to attenuate many of the physiological effects of the stress response.

The endocannabinoid system is made up of cannabinoid receptors, the fatty acid signaling molecules that bind to and activate these receptors, and the enzymes that synthesize and catabolize these endocannabinoid signaling molecules.

Cannabinoid research has recently grown substantially, due in no small part to the development of genetic research models as well as highly selective pharmaceutical tools.

The purpose of this minireview is to discuss a subset of the many parallels between cannabinoid and behavioral neuroimmunology research, with specific discussion of interactions between the endocannabinoid system and psychological stress, emotionality, and inflammation.”

http://www.ncbi.nlm.nih.gov/pubmed/24953427

Role of ionotropic cannabinoid receptors in peripheral antinociception and antihyperalgesia

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“Although cannabinoids have been used for millennia for treating pain and other symptoms, their mechanisms of action remain obscure.

With the heralded identification of multiple G-protein-coupled receptors (GPCRs) mediating cannabinoid effects nearly two decades ago, the mystery of cannabinoid pharmacology was thought to be solved…

Despite the wealth of information on cannabinoid-induced peripheral antihyperalgesic and antinociceptive effects in many pain models, the molecular mechanism(s) for these actions remains unknown.

Although metabotropic cannabinoid receptors have important roles in many pharmacological actions of cannabinoids, recent studies have led to the recognition of a family of at least five ionotropic cannabinoid receptors (ICRs). The known ICRs are members of the family of transient receptor potential (TRP) channels and include TRPV1, TRPV2, TRPV4, TRPM8 and TRPA1.

Cannabinoid activation of ICRs can result in desensitization of the TRPA1 and TRPV1 channel activities, inhibition of nociceptors and antihyperalgesia and antinociception in certain pain models.

Thus, cannabinoids activate both metabotropic and ionotropic mechanisms to produce peripheral analgesic effects.”

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2863326/

TRP Channel Cannabinoid Receptors in Skin Sensation, Homeostasis, and Inflammation.

“In the skin, cannabinoid lipids, whether of endogenous or exogenous origin, are capable of regulating numerous sensory, homeostatic and inflammatory events.

Although many of these effects are mediated by metabotropic CB receptors, a growing body of evidence has revealed that multiple members of the transient receptor potential (TRP) ion channel family can act as “ionotropic cannabinoid receptors”.

Furthermore, many of these same TRP channels are intimately involved in cutaneous processes that include the initiation of pain, temperature, and itch perception, the maintenance of epidermal homeostasis, the regulation of hair follicles and sebaceous glands, and the modulation of dermatitis.

Ionotropic cannabinoid receptors therefore represent potentially attractive targets for the therapeutic use of cannabinoids to treat sensory and dermatological diseases.

Furthermore, the interactions between neurons and other cell types that are mediated by cutaneous ionotropic cannabinoid receptors are likely to be recapitulated during physiological and pathophysiological processes in the central nervous system and elsewhere, making the skin an ideal setting in which to dissect general complexities of cannabinoid signaling.”

http://www.ncbi.nlm.nih.gov/pubmed/24915599

Reduced endocannabinoid immune modulation by a common cannabinoid 2 (CB2) receptor gene polymorphism: possible risk for autoimmune disorders.

Publication cover image

“Immune system responsiveness results from numerous factors, including endogenous cannabinoid signaling in immunocytes termed the “immunocannabinoid” system. This system can be an important signaling pathway for immune modulation.

To assess the immunomodulating role of the cannabinoid 2 (CB2) receptor, we sought polymorphisms in the human gene, identified a common dinucleotide polymorphism, and investigated its effect on endocannabinoid-induced inhibition of T lymphocyte proliferation.

Collectively, these results demonstrate reduced endogenous fatty acid amide immunomodulatory responses in individuals with the CB2 188-189 GG/GG genotype and suggest that this CB2 gene variation may be a risk factor for autoimmunity.

The results also support the proposition that the CB2 receptor may represent a novel pharmacological target for selective agonists designed to suppress autoreactive immune responses”

https://jlb.onlinelibrary.wiley.com/doi/full/10.1189/jlb.0205111

https://www.ncbi.nlm.nih.gov/pubmed/15845647

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

“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

Signaling through cannabinoid receptor 2 suppresses murine dendritic cell migration by inhibiting matrix metalloproteinase 9 expression

“The cannabinoid system consists of cannabinoid receptors and their ligands, including endocannabinoids, synthetic cannabinoid receptor agonists and antagonists, and phytocannabinoids.

Administration of cannabinoid receptor 2 (CB2R) agonists in inflammatory and autoimmune disease and CNS injury models results in significant attenuation of clinical disease, and reduction of inflammatory mediators.

…cannabinoids contribute to resolve acute inflammation and to reestablish homeostasis.

Selective CB2R agonists might be valuable future therapeutic agents for the treatment of chronic inflammatory conditions by targeting activated immune cells, including DCs.

Because of their anti-inflammatory functions targeting various immune cells, CB2R agonists could represent valuable therapeutic agents for the treatment of chronic inflammatory conditions.”

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3488886/

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

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“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/

Cannabinoid Modulation of Neuroinflammatory Disorders

Table 1.

Cannabis sativa is a herb belonging to the Cannabaceae family, characterized by palmate leaves and numerous fibers. Its first record as a medicine dates back to 5000 years ago and it was found in China, where cannabis was used for a myriad of purposes and diseases, including malaria, neuropathic pain, nausea, sexual dysfunction and constipation.

The use of cannabis spread from Central Asia and deeply influenced Indian folk medicine. However, sedative and psychotropic effects of cannabis turned it into a recreational drug. This fact resulted in discrimination against the consumption of the cannabis plant and its derivatives, which delayed the scientific findings in this field…

In recent years, a growing interest has been dedicated to the study of the endocannabinoid system. The isolation of Cannabis sativa main psychotropic compound, Δ(9)-tetrahydrocannabinol (THC), has led to the discovery of an atypical neurotransmission system that modulates the release of other neurotransmitters and participates in many biological processes, including the cascade of inflammatory responses.

In this context, cannabinoids have been studied for their possible therapeutic properties in neuroinflammatory diseases. In this review, historic and biochemical aspects of cannabinoids are discussed, as well as their function as modulators of inflammatory processes and therapeutic perspectives for neurodegenerative disorders, particularly, multiple sclerosis.

Cannabinoid compounds may be extracted from the plant (phytocannabinoids) or be artificially obtained (synthetic cannabinoids)…

To date, it is still impossible to prove or rule out all benefits of cannabis described empirically by ancient herbal practitioners. For now, science aims to understand how cannabinoid compounds are associated with neuroinflammation and how cannabis-based medicine can help millions of patients worldwide.”

 http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3386505/

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

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“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 autoreactive lymphocytes in the central nervous system via the CB2 receptor.

The cannabinoid system is evolutionally conserved and is present in invertebrates and vertebrates. One of the best-studied cannabinoids is Δ9-tetrahydrocannabinol (THC), the predominant active component of Cannabis sativa or marijuana.

The marijuana plant has been exploited by humans since their early history and was used for centuries in Asian medicine to reduce the severity of pain, inflammation and asthma. However, only recently have the mechanisms of the medicinal properties of THC begun to be understood. This understanding is largely due to the identification and cloning of two cannabinoid receptors.

The cannabinoid system is now recognized as a regulator of both the nervous and immune systems.

Although marijuana has been used for centuries for the treatment of a variety of disorders, its therapeutic mechanisms are only now being understood.

The best-studied plant cannabinoid, delta9-tetrahydrocannabinol (THC), produced by Cannabis sativa and found in marijuana, has shown evidence of being immunosuppressive in both in vivo and in vitro.

These studies are theoretically in agreement with the suggestions of others that cannabinoid receptor agonists would be beneficial for the treatment of MS in humans.”

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2219523/