Crosstalk between endocannabinoid and immune systems: a potential dysregulation in depression?

“The endocannabinoid (eCB) system, an endogenous lipid signaling system, appears to be dysregulated in depression. The role of endocannabinoids (eCBs) as potent immunomodulators, together with the accumulating support for a chronic low-grade inflammatory profile in depression, suggests a compelling hypothesis for a fundamental impairment in their intercommunication, in depression.


We aim to review previous literature on individual associations between the immune and eCB systems and depression. It will focus on peripheral and central mechanisms of crosstalk between the eCB and immune systems. A potential dysregulation in this crosstalk will be discussed in the context of depression.


Investigations largely report a hypoactivity of the eCB system and increased inflammatory markers in individuals with depression. Findings depict a multifaceted communication whereby immunocompetent and eCB-related cells can both influence the suppression and enhancement of the other’s activity in both the periphery and central nervous system. A dysregulation of the eCB system, as seen in depression, appears to be associated with central and peripheral concentrations of inflammatory agents implicated in the pathophysiology of this illness.


The eCB and immune systems have been individually associated with and implicated in pathogenic mechanisms of depression. Both systems tightly regulate the other’s activity. As such, a dysregulation in this crosstalk has potential to influence the onset and maintenance of this neuropsychiatric illness. However, few studies have investigated both systems and depression conjointly. This review highlights the demand to consider joint eCB-immune interactions in the pathoetiology of depression.”

The prescription of medical cannabis by a transitional pain service to wean a patient with complex pain from opioid use following liver transplantation: a case report.

Canadian Journal of Anesthesia/Journal canadien d'anesthésie

“The purpose of this case report is to describe a patient with a preoperative complex pain syndrome who underwent liver transplantation and was able to reduce his opioid consumption significantly following the initiation of treatment with medical cannabis.


A 57-yr-old male with a history of hepatitis C cirrhosis underwent liver transplantation. Preoperatively, he was taking hydromorphone 2-8 mg⋅day-1 for chronic abdominal pain. Postoperatively, he was given intravenous patient-controlled analgesia through which he received hydromorphone 30 mg⋅day-1. Our multidisciplinary Transitional Pain Service was involved with managing his moderate to severe acute postsurgical pain in hospital and continued with weaning him from opioid medications after discharge. It was difficult to wean the patient from opioids, and he was subsequently given medical cannabis at six weeks postoperatively with remarkable effect. By the fifth postoperative month, his use of opioids had tapered to 6 mg⋅day-1 of hydromorphone, and his functional status was excellent on this regimen.


Reductions in opioid consumption were achieved with the administration of medical cannabis in a patient with acute postoperative pain superimposed on a chronic pain syndrome and receiving high doses of opioids. Concurrent benefits of initiating medical cannabis may include improvements in pain profile and functional status along with reductions in opioid-related side effects. This highlights the potential for medical cannabis as an adjunct medication for weaning patients from opioid use.”

Endocannabinoid signaling mediates oxytocin-driven social reward.

Image result for Proc Natl Acad Sci U S A.

“Marijuana exerts profound effects on human social behavior, but the neural substrates underlying such effects are unknown. Here we report that social contact increases, whereas isolation decreases, the mobilization of the endogenous marijuana-like neurotransmitter, anandamide, in the mouse nucleus accumbens (NAc), a brain structure that regulates motivated behavior. The results indicate that anandamide-mediated signaling at CB1 receptors, driven by oxytocin, controls social reward. Deficits in this signaling mechanism may contribute to social impairment in autism spectrum disorders and might offer an avenue to treat these conditions.”

“In conclusion, our results illuminate a mechanism underlying the prosocial actions of oxytocin, and provide unexpected insights on possible neural substrates involved in the social facilitation caused by marijuana. Pharmacological modulation of oxytocin-driven anandamide signaling (by using, for example, FAAH inhibitors) might open new avenues to treat social impairment in autism spectrum disorders.”

Inhibiting Heat Shock Proteins Can Potentiate the Cytotoxic Effect of Cannabidiol in Human Glioma Cells.

“Cannabinoids possess a number of characteristics that make them putative anticancer drugs, and their value as such is currently being explored in a number of clinical studies.

To further understand the roles that cannabinoids may have, we performed gene expression profiling in glioma cell lines cultured with cannabidiol (CBD) and/or Δ9-tetrahydrocannabinol (THC), and pursued targets identified by this screening.

Results showed that a large number of genes belonging to the heat shock protein (HSP) super-family were up-regulated following treatment, specifically with CBD. Increases were observed both at the gene and protein levels and arose as a consequence of increased generation of ROS by CBD, and correlated with an increase in a number of HSP client proteins. Furthermore, increases impeded the cytotoxic effect of CBD; an effect that was improved by co-culture with pharmacalogical inhibitors of HSPs. Similarly, culturing glioma cells with CBD and HSP inhibitors increased radiosensitivity when compared to CBD-alone.

Taken together, these data indicate that the cytotoxic effects of CBD can be diminished by HSPs that indirectly rise as a result of CBD use, and that the inclusion of HSP inhibitors in CBD treatment regimens can enhance the overall effect.”

Cannabidiol protects an in vitro model of the blood brain barrier (BBB) from oxygen-glucose deprivation via PPARγ and 5-HT1A.

“In vivo and in vitro studies have demonstrated a protective effect of cannabidiol (CBD) in reducing infarct size in stroke models, and against epithelial barrier damage in numerous disease models.

We aimed to investigate whether CBD also affects blood-brain barrier (BBB) permeability following ischaemia.

These data suggest that activity at the BBB could represent an as yet unrecognised mechanism of CBD-induced neuroprotection in ischaemic stroke, mediated by PPARγ and 5-HT1A .”

Addressing the stimulant treatment gap: A call to investigate the therapeutic benefits potential of cannabinoids for crack-cocaine use.

“Crack-cocaine use is prevalent in numerous countries, yet concentrated primarily – largely within urban contexts – in the Northern and Southern regions of the Americas. It is associated with a variety of behavioral, physical and mental health and social problems which gravely affect users and their environments. Few evidence-based treatments for crack-cocaine use exist and are available to users in the reality of street drug use. Numerous pharmacological treatments have been investigated but with largely disappointing results.

An important therapeutic potential for crack-cocaine use may rest in cannabinoids, which have recently seen a general resurgence for varied possible therapeutic usages for different neurological diseases.

Distinct potential therapeutic benefits for crack-cocaine use and common related adverse symptoms may come specifically from cannabidiol (CBD) – one of the numerous cannabinoid components found in cannabis – with its demonstrated anxiolytic, anti-psychotic, anti-convulsant effects and potential benefits for sleep and appetite problems.

The possible therapeutic prospects of cannabinoids are corroborated by observational studies from different contexts documenting crack-cocaine users’ ‘self-medication’ efforts towards coping with crack-cocaine-related problems, including withdrawal and craving, impulsivity and paranoia. 

Cannabinoid therapeutics offer further benefits of being available in multiple formulations, are low in adverse risk potential, and may easily be offered in community-based settings which may add to their feasibility as interventions for – predominantly marginalized – crack-cocaine user populations.

Supported by the dearth of current therapeutic options for crack-cocaine use, we are advocating for the implementation of a rigorous research program investigating the potential therapeutic benefits of cannabinoids for crack-cocaine use.

Given the high prevalence of this grave substance use problem in the Americas, opportunities for such research should urgently be created and facilitated there.”

Cannabinoid WIN55, 212-2 induces cell cycle arrest and inhibits the proliferation and migration of human BEL7402 hepatocellular carcinoma cells.

“Hepatocellular carcinoma (HCC) is the leading cause of cancer-associated mortality worldwide; however, only limited therapeutic treatments are currently available.

The present study aimed to investigate the effects of cannabinoids as novel therapeutic targets in HCC…

These results suggested that cannabinoid receptor agonists, including WIN, may be considered as novel therapeutics for the treatment of HCC.”

Controlled downregulation of the cannabinoid CB1 receptor provides a promising approach for the treatment of obesity and obesity-derived type 2 diabetes.

“Increased activity of the endocannabinoid system has emerged as a pathogenic factor in visceral obesity, which is a risk factor for type 2 diabetes mellitus (T2DM).

The endocannabinoid system is composed of at least two G-protein-coupled receptors (GPCRs), the cannabinoid receptor type 1 (CB1), and the cannabinoid receptor type 2 (CB2).

Downregulation of CB1 activity in rodents and humans has proven efficacious to reduce food intake, abdominal adiposity, fasting glucose levels, and cardiometabolic risk factors.

Unfortunately, downregulation of CB1 activity by universally active CB1 inverse agonists has been found to elicit psychiatric side effects, which led to the termination of using globally active CB1 inverse agonists to treat diet-induced obesity.

Interestingly, preclinical studies have shown that downregulation of CB1 activity by CB1 neutral antagonists or peripherally restricted CB1 inverse agonists provided similar anorectic effects and metabolic benefits without psychiatric side effects seen in globally active CB1 inverse agonists.

Furthermore, downregulation of CB1 activity may ease endoplasmic reticulum and mitochondrial stress which are contributors to obesity-induced insulin resistance and type 2 diabetes.

This suggests new approaches for cannabinoid-based therapy in the management of obesity and obesity-related metabolic disorders including type 2 diabetes.”

Peripherally Restricted Cannabinoids for the Treatment of Pain.

“The use of cannabinoids for the treatment of chronic diseases has increased in the United States, with 23 states having legalized the use of marijuana.

Although currently available cannabinoid compounds have shown effectiveness in relieving symptoms associated with numerous diseases, the use of cannabis or cannabinoids is still controversial mostly due to their psychotropic effects (e.g., euphoria, laughter) or central nervous system (CNS)-related undesired effects (e.g., tolerance, dependence).

A potential strategy to use cannabinoids for medical conditions without inducing psychotropic or CNS-related undesired effects is to avoid their actions in the CNS.

This approach could be beneficial for conditions with prominent peripheral pathophysiologic mechanisms (e.g., painful diabetic neuropathy, chemotherapy-induced neuropathy).

In this article, we discuss the scientific evidence to target the peripheral cannabinoid system as an alternative to cannabis use for medical purposes, and we review the available literature to determine the pros and cons of potential strategies that can be used to this end.”

The Cannabinoid Receptor CB1 Interacts with the WAVE1 Complex and Plays a Role in Actin Dynamics and Structural Plasticity in Neurons.

“The molecular composition of the cannabinoid type 1 (CB1) receptor complex beyond the classical G-protein signaling components is not known.

Using proteomics on mouse cortex in vivo, we pulled down proteins interacting with CB1 in neurons and show that the CB1 receptor assembles with multiple members of the WAVE1 complex and the RhoGTPase Rac1 and modulates their activity…

This study reports novel signaling mechanisms for cannabinoidergic modulation of the nervous system and demonstrates a previously unreported role for the WAVE1 complex in therapeutic applications of cannabinoids.”