Tag Archives: cannabinoid receptors

The endocannabinoid system of the skin. A potential approach for the treatment of skin disorders.

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Biochemical Pharmacology

“The skin is the largest organ of the body and has a complex and very active structure that contributes to homeostasis and provides the first line defense against injury and infection.

In the past few years it has become evident that the endocannabinoid system (ECS) plays a relevant role in healthy and diseased skin.

Specifically, we review how the dysregulation of ECS has been associated to dermatological disorders such as atopic dermatitis, psoriasis, scleroderma and skin cancer. Therefore, the druggability of the ECS could open new research avenues for the treatment of the pathologies mentioned.

Numerous studies have reported that phytocannabinoids and their biological analogues modulate a complex network pharmacology involved in the modulation of ECS, focusing on classical cannabinoid receptors, transient receptor potential channels (TRPs), and peroxisome proliferator-activated receptors (PPARs).

The combined targeting of several end-points seems critical to provide better chances of therapeutically success, in sharp contrast to the one-disease-one-target dogma that permeates current drug discovery campaigns.”

https://www.ncbi.nlm.nih.gov/pubmed/30138623

https://www.sciencedirect.com/science/article/abs/pii/S0006295218303484

Cannabinoids and reduced risk of hepatic steatosis in HIV-HCV co-infection: paving the way for future clinical research

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“Whether or not cannabis itself or cannabinoids contained in it may help to reduce hepatic steatosis in HIV-HCV coinfected patients remains an open question. The existing body of knowledge on the interactions between cannabis and the liver suggest a protective effect of cannabinoids on insulin resistance, diabetes, and NAFLD in the general population. Clinical research with randomized study designs is needed to evaluate the efficacy and safety of cannabis-based pharmacotherapies in HIV-HCV coinfected patients. Targeting the endocannabinoid system seems essential to differently manage several pathological conditions such as intestinal inflammation, obesity, diabetes and fatty liver disease. However, to date, few drugs have been tested in clinical trials. CB1-antagonists and CB2 agonists appear to be viable therapeutic options that need to be explored for the management of liver diseases. As HCV cure rates are coming close to 100% in the era of direct-acting antivirals, it is especially important to be able to identify modifiable risk factors of complications and death in HIV-HCV coinfected patients, as well as possible levers for intervention. Given the persistence of metabolic risk factors after HCV eradication, cannabis-based therapies need to be evaluated both as preventive and therapeutic tools in patients living with or at risk of liver steatosis, possibly in combination with existing conventional approaches.”

https://www.tandfonline.com/doi/full/10.1080/14787210.2018.1473764

Cannabinoid pharmacology/therapeutics in chronic degenerative disorders affecting the central nervous system.

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 Biochemical Pharmacology “The endocannabinoid system (ECS) exerts a modulatory effect of important functions such as neurotransmission, glial activation, oxidative stress, or protein homeostasis.

Dysregulation of these cellular processes is a common neuropathological hallmark in aging and in neurodegenerative diseases of the central nervous system (CNS). The broad spectrum of actions of cannabinoids allows targeting different aspects of these multifactorial diseases.

In this review, we examine the therapeutic potential of the ECS for the treatment of chronic neurodegenerative diseases of the CNS focusing on Alzheimer’s disease, Parkinson’s disease, Huntington’s disease, and amyotrophic lateral sclerosis.

First, we describe the localization of the molecular components of the ECS and how they are altered under neurodegenerative conditions, either contributing to or protecting cells from degeneration.

Second, we address recent advances in the modulation of the ECS using experimental models through different strategies including the direct targeting of cannabinoid receptors with agonists or antagonists, increasing the endocannabinoid tone by the inhibition of endocannabinoid hydrolysis, and activation of cannabinoid receptor-independent effects.

Preclinical evidence indicates that cannabinoid pharmacology is complex but supports the therapeutic potential of targeting the ECS.

Third, we review the clinical evidence and discuss the future perspectives on how to bridge human and animal studies to develop cannabinoid-based therapies for each neurodegenerative disorder.

Finally, we summarize the most relevant opportunities of cannabinoid pharmacology related to each disease and the multiple unexplored pathways in cannabinoid pharmacology that could be useful for the treatment of neurodegenerative diseases.”

https://www.ncbi.nlm.nih.gov/pubmed/30121249

https://www.sciencedirect.com/science/article/abs/pii/S000629521830337X

Revisiting cannabinoid receptor 2 expression and function in murine retina.

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 Neuropharmacology

“The cannabinoid receptor CB2 plays a significant role in the regulation of immune function whereas neuronal expression remains a subject of contention. Multiple studies have described CB2 in retina and a recent study showed that CB2 deletion altered retinal visual processing. We revisited CB2 expression using immunohistochemistry and a recently developed CB2-eGFP reporter mouse. We examined the consequence of acute vs. prolonged CB2 deactivation on the electroretinogram (ERG) responses. We also examined lipidomics in CB2 knockout mice and potential changes in microglia using Scholl analysis. Consistent with a published report, in CB2 receptor knockout mice see an increased ERG scotopic a-wave, as well as stronger responses in dark adapted cone-driven ON bipolar cells and, to a lesser extent cone-driven ON bipolar cells early in light adaptation. Significantly, however, acute block with CB2 antagonist, AM630, did not mimic the results observed in the CB2 knockout mice whereas chronic (7 days) block did. Immunohistochemical studies show no CB2 in retina under non-pathological conditions, even with published antibodies. Retinal CB2-eGFP reporter signal is minimal under baseline conditions but upregulated by intraocular injection of either LPS or carrageenan. CB2 knockout mice see modest declines in a broad spectrum of cannabinoid-related lipids. The numbers and morphology of microglia were unaltered. In summary minimal CB2 expression is seen in healthy retina. CB2 appears to be upregulated under pathological conditions. Previously reported functional consequences of CB2 deletion are an adaptive response to prolonged blockade of these receptors. CB2 therefore impacts retinal signaling but perhaps in an indirect, potentially extra-ocular fashion.”

https://www.ncbi.nlm.nih.gov/pubmed/30121200

https://www.sciencedirect.com/science/article/pii/S0028390818304775?via%3Dihub

The novel peripherally active cannabinoid type 1 and serotonin type 3 receptor agonist AM9405 inhibits gastrointestinal motility and reduces abdominal pain in mouse models mimicking irritable bowel syndrome.

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European Journal of Pharmacology

“The endocannabinoid system (ECS) plays a crucial role in numerous physiological processes in the central and peripheral nervous systems. In the gastrointestinal (GI) tract, selective cannabinoid (CB) receptor agonists exert potent inhibitory actions on motility and pain signalling. In the present study, we used mouse models of diarrhea, hypermotility, and abdominal pain to examine whether a novel synthetic CB1 receptor agonist AM9405 [(2-(2,6-dihydroxy-4-(2-methyloctan-2-yl)phenyl)-1,3-dimethyl-1H-benzo[d]imidazol-3-ium bromide); also known as GAT379] exhibits effects of potential therapeutic relevance. AM9405 significantly slowed mouse intestinal motility in physiological conditions. Moreover, AM9405 reversed hypermotility and reduced pain in mouse models mimicking symptoms of functional GI disorders, such as stress-induced diarrhoea and writhing test. Interestingly, some of the effects of AM9405 were blocked by a 5-HT3 antagonist suggesting interaction with 5-HT3 receptors. In our study we show that combining CB1 agonism with 5-HT3 agonism may alter physiological functions and experimental pathophysiologies in a manner that make such compounds promising drugs for the future treatment of functional GI disorders.”

https://www.ncbi.nlm.nih.gov/pubmed/30121173

https://www.sciencedirect.com/science/article/pii/S0014299918304734?via%3Dihub

New approaches and challenges to targeting the endocannabinoid system.

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“The endocannabinoid signalling system was discovered because receptors in this system are the targets of compounds present in psychotropic preparations of Cannabis sativa. The search for new therapeutics that target endocannabinoid signalling is both challenging and potentially rewarding, as endocannabinoids are implicated in numerous physiological and pathological processes. Hundreds of mediators chemically related to the endocannabinoids, often with similar metabolic pathways but different targets, have complicated the development of inhibitors of endocannabinoid metabolic enzymes but have also stimulated the rational design of multi-target drugs. Meanwhile, drugs based on botanical cannabinoids have come to the clinical forefront, synthetic agonists designed to bind cannabinoid receptor 1 with very high affinity have become a societal threat and the gut microbiome has been found to signal in part through the endocannabinoid network. The current development of drugs that alter endocannabinoid signalling and how this complex system could be pharmacologically manipulated in the future are described in this Opinion article.”

https://www.ncbi.nlm.nih.gov/pubmed/30116049
https://www.nature.com/articles/nrd.2018.115

Cannabinoid signalling in the immature brain: encephalopathies and neurodevelopmental disorders.

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Biochemical Pharmacology

“The endocannabinoid system exerts a crucial neuromodulatory role in many brain areas that is essential for proper regulation of neuronal activity. The role of cannabinoid signalling controlling neuronal activity in the adult brain is also evident when considering its contribution to adult brain insults or neurodegenerative diseases.

In the context of brain genetic or acquired encephalopathies administration of cannabinoid-based molecules has demonstrated to exert symptomatic relief and hence, they are proposed as new potential therapeutic compounds.

This review article summarizes the main evidences indicating the beneficial action of cannabinoid-derived molecules in preclinical models of neonatal hypoxia/ischemic damage. In a second part, we discuss the available evidences of therapeutic actions of cannabidiol in children with refractory epilepsy syndromes. Finally, we discuss the current view of cannabinoid signalling mechanisms active in the immature brain that affect in neural cell fate and can contribute to long-term neural cell plasticity.”

https://www.ncbi.nlm.nih.gov/pubmed/30118663

https://www.sciencedirect.com/science/article/abs/pii/S0006295218303344

Acute inflammation: endogenous cannabinoids mellow the harsh proinflammatory environment.

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“Under normal conditions, there is a paucity of neutrophils within the intestinal mucosa; however, these innate immune cells rapidly infiltrate the mucosa in response to infection and are critical for pathogen control. Unfortunately, these cells can cause extensive damage to the intestine if the initial inflammatory influx is not resolved. Factors that promote resolution of inflammation are of great interest, as they have therapeutic potential for limiting uncontrolled inflammatory damage. In this issue of the JCI, Szabady et al. demonstrate that the multidrug resistance transporter P-glycoprotein (P-gp) secretes endocannabinoids into the intestinal lumen that counteract the proinflammatory actions of the eicosanoid hepoxilin A3, which is secreted into the lumen by the efflux pump MRP2 and serves as a potent neutrophil chemoattractant. Moreover, the antiinflammatory actions of P-gp-secreted endocannabinoids were mediated by peripheral cannabinoid receptor CB2 on neutrophils. Together, the results of this study identify an important mechanism by which endogenous endocannabinoids facilitate the resolution of inflammation; this mechanism has potential to be therapeutically exploited.”

 https://www.ncbi.nlm.nih.gov/pubmed/30102253
https://www.jci.org/articles/view/122885
“Cannabinoids as novel anti-inflammatory drugs” http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2828614/

Glial Endocannabinoid System in Pain Modulation.

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“Pain is affecting the human for centuries and there still is no satisfactory strategy for patients suffering pain particularly chronic pain although intensive studies about its mechanism have been performed in order to improve the treatment of pain.

Cannabinoid is a group of chemicals extracted from plants and has a long history in treating pain through the endogenous cannabinoid receptor in the body, however, its application in pain treatment is limited due to its inverse effects.

Recent studies have indicated that glial cells play critical role in mediating pain processing through multiple pathway, including excitatory and inhibitory neurotransmission in different levels of the nervous system.

Furthermore, the glial cells are found to express cannabinoid receptors.

This review summarized the recent studies about the cannabinoid system in glial cells, which may provide some insight for the studying of pain.”

https://www.ncbi.nlm.nih.gov/pubmed/30084280

https://www.tandfonline.com/doi/abs/10.1080/00207454.2018.1503178

Targeted inhibition of the type 2 cannabinoid receptor is a novel approach to reduce renal fibrosis.

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Kidney International Home

“The cannabinoid receptor type 2 (CB2) is a G protein-coupled seven transmembrane receptor that transmits endogenous cannabinoid signaling. The role of CB2 in the pathogenesis of kidney injury and fibrosis remains poorly understood.

Here we demonstrate that CB2 was induced, predominantly in kidney tubular epithelium, in various models of kidney disease induced by unilateral ureteral obstruction, adriamycin or ischemia/reperfusion injury.

By using in silico screening and medicinal chemistry modifications, we discovered a novel compound, XL-001, that bound to CB2 with high affinity and selectivity and acted as an inverse agonist. Delayed administration of XL-001 was also effective in ameliorating kidney fibrosis and inflammation.

Thus, CB2 is a pathogenic mediator in kidney fibrosis and targeted inhibition with the novel inverse agonist XL-001 may provide a strategy in the fight against fibrotic kidney diseases.”

 https://www.ncbi.nlm.nih.gov/pubmed/30093080
https://www.kidney-international.org/article/S0085-2538(18)30397-1/fulltext