Category Archives: Endocannabinoid System

Peripherally selective cannabinoid 1 receptor (CB1R) agonists for the treatment of neuropathic pain

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 Journal of Medicinal Chemistry

“Alleviation of neuropathic pain by cannabinoids is limited by their central nervous system (CNS) side effects. Indole and indene compounds were engineered for high hCB1R affinity, peripheral selectivity, metabolic stability, and in vivo efficacy. An epithelial cell line assay identified candidates with <1% blood-brain barrier penetration for testing in a rat neuropathy induced by unilateral sciatic nerve entrapment (SNE). The SNE-induced mechanical allodynia was reversibly suppressed, partially or completely, after intraperitoneal or oral administration of several indenes. At doses that relieve neuropathy symptoms, the indenes completely lacked, while the brain-permeant CB1R agonist HU-210 (1) exhibited strong CNS side effects, in catalepsy, hypothermia, and motor incoordination assays. Pharmacokinetic findings of ~0.001 cerebrospinal fluid:plasma ratio further supported limited CNS penetration. Pretreatment with selective CB1R or CB2R blockers suggested mainly CB1R contribution to an indene’s anti-allodynic effects. Therefore, this class of CB1R agonists holds promise as a viable treatment for neuropathic pain.”

http://pubs.acs.org/doi/abs/10.1021/acs.jmedchem.6b00516

Expression of Cannabinoid Receptors in Human Osteoarthritic Cartilage: Implications for Future Therapies

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“Cannabinoids have shown to reduce joint damage in animal models of arthritis and reduce matrix metalloproteinase expression in primary human osteoarthritic (OA) chondrocytes.

Chondrocytes from OA joints were shown to express a wide range of cannabinoid receptors even in degenerate tissues, demonstrating that these cells could respond to cannabinoids.

Cannabinoids designed to bind to receptors inhibiting the catabolic and pain pathways within the arthritic joint, while avoiding psychoactive effects, could provide potential arthritis therapies.

Cannabinoids were originally derived from the cannabis plant, Cannabis sativa, which has been used medicinally and recreationally for many years because of its anti-inflammatory, analgesic, and psychoactive properties.”

http://online.liebertpub.com/doi/full/10.1089/can.2015.0001

Endocannabinoids: new targets for drug development.

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“The possible therapeutic use of marijuana s active principles, the cannabinoids, is currently being debated.

It is now known that these substances exert several of their pharmacological actions by activating specific cell membrane receptors, the CB1 and CB2 cannabinoid receptor subtypes.

This knowledge led to the design of synthetic cannabinoid agonists and antagonists with high therapeutic potential.

The recent discovery of the endocannabinoids, i.e. endogenous metabolites capable of activating the cannabinoid receptors, and the understanding of the molecular mechanisms leading to their biosynthesis and inactivation, opened a new era in research on the pharmaceutical applications of cannabinoids.

Ongoing studies on the pathological and physiological conditions regulating the tissue levels of endocannabinoids, and on the pharmacological activity of these compounds and their derivatives, may provide a lead for the development of new drugs for the treatment of nervous and immune disorders, cardiovascular diseases, pain, inflammation and cancer.

These studies are reviewed in this article with special emphasis on the chemical features that determine the interaction of endocannabinoids with the proteins mediating their activity and degradation.”

http://www.ncbi.nlm.nih.gov/pubmed/10903398

Cannabinoids biology: the search for new therapeutic targets.

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“Cannabinoids, in the form of marijuana plant extracts, have been used for thousands of years for a wide variety of medical conditions, ranging from general malaise and mood disorders to more specific ailments, such as pain, nausea, and muscle spasms.

The discovery of tetrahydrocannabinol, the active principal in marijuana, and the identification and cloning of two cannabinoid receptors (i.e., CB1 and CB2) has subsequently led to biomedical appreciation for a family of endocannabinoid lipid transmitters.

The biosynthesis and catabolism of the endocannabinoids and growing knowledge of their broad physiological roles are providing insight into potentially novel therapeutic targets.

Compounds directed at one or more of these targets may allow for cannabinoid-based therapeutics with limited side effects and abuse liability.”

http://www.ncbi.nlm.nih.gov/pubmed/16809476

Cannabinoid system in the skin – a possible target for future therapies in dermatology.

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“Cannabinoids and their derivatives are group of more than 60 biologically active chemical agents, which have been used in natural medicine for centuries.

The major agent of exogenous cannabinoids is Delta(9)-tetrahydrocannabinol (Delta(9)-THC), natural psychoactive ingredient of marijuana.

Recent discoveries of endogenous cannabinoids (e.g. arachidonoylethanolamide, 2-arachidonoylglycerol or palmithyloethanolamide) and their receptors initiated discussion on the role of cannabinoid system in physiological conditions as well as in various diseases.

Based on the current knowledge, it could be stated that cannabinoids are important mediators in the skin, however their role have not been well elucidated yet.

In our review, we summarized the current knowledge about the significant role of the cannabinoid system in the cutaneous physiology and pathology, pointing out possible future therapeutic targets.”

http://www.ncbi.nlm.nih.gov/pubmed/19664006

Characterization of delta9-tetrahydrocannabinol and anandamide antinociception in nonarthritic and arthritic rats.

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“The hypothesis was tested that THC and anandamide elicit antinociception in the paw pressure test, and that arthritic rats would exhibit a different response.

THC and anandamide appear to release an as yet unknown endogenous opioid, because naloxone significantly blocked their effects.

This study indicates that anandamide and THC may act at different receptor sites to modulate endogenous opioid levels in mechanical nociception.”

http://www.ncbi.nlm.nih.gov/pubmed/9610941

Effects of cannabinoids on nitric oxide production by chondrocytes and proteoglycan degradation in cartilage.

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“Cannabinoids have been reported to have anti-inflammatory effects and reduce joint damage in animal models of arthritis.

This suggests a potential therapeutic role in arthritis of this group of compounds.

Cannabinoids were studied to determine whether they have direct effects on chondrocyte metabolism resulting in cartilage protection.

Synthetic cannabinoids, R-(+)-Win-55,212 (Win-2) and S-(-)-Win-55,212 (Win-3) and the endocannabinoid, anandamide, were investigated on unstimulated or IL-1-stimulated nitric oxide (NO) production in bovine articular chondrocytes as well as on cartilage proteoglycan breakdown in bovine nasal cartilage explants.

Win-2 significantly inhibited (P < 0.05) NO production in chondrocytes at 1-10 microM concentrations. The combined CB(1) and CB(2) cannabinoid receptor antagonists, AM281 and AM630, respectively, at 100 microM did not block this effect, but instead they potentiated it. Anandamide and Win-2 (5-50 microM) also inhibited the release of sulphated glycosaminoglycans in bovine cartilage explants.

The results suggest that some cannabinoids may prevent cartilage resorption, in part, by inhibiting cytokine-induced NO production by chondrocytes and also by inhibiting proteoglycan degradation.”

http://www.ncbi.nlm.nih.gov/pubmed/15670582

Effect of anandamide in Plasmodium Berghei-infected mice.

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“Eryptosis, the suicidal death of erythrocytes, is characterized by exposure of phosphatidylserine at the erythrocyte surface and cell shrinkage.

Triggers of eryptosis include anandamide.

Enhanced eryptosis of infected human erythrocytes is expected to delay the development of parasitaemia during infection with Plasmodium, the parasite causing malaria.

The present experiments aimed to test, whether anandamide influences eryptosis, parasite growth and/or host survival during in vitro or in vivo infection with Plasmodia.

In vivo administration of anandamide blunted the parasitaemia and significantly enhanced the survival of P. berghei-infected mice.

In conclusion, anandamide stimulated eryptosis of infected erythrocytes thus counteracting parasitaemia and a lethal course of the disease.”

http://www.ncbi.nlm.nih.gov/pubmed/20798520

Cannabinoid receptor 2 modulates susceptibility to experimental cerebral malaria through a CCL17-dependent mechanism.

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“Cerebral malaria (CM) is a severe and often fatal complication of Plasmodium falciparum infection. It is characterized by parasite sequestration, a breakdown of the blood-brain-barrier and a strong inflammation in the brain.

We investigated the role of the cannabinoid receptor 2 (CB2), an important modulator of neuroinflammatory responses, in experimental cerebral malaria (ECM).

Strikingly, mice with a deletion of the CB2-encoding gene (Cnr2-/-) mice inoculated with Plasmodium berghei ANKA-erythrocytes exhibited enhanced survival and a diminished blood-brain-barrier disruption.

Therapeutic application of a specific CB2 antagonist also conferred increased ECM resistance in wild type mice.

Hematopoietic-derived immune cells were responsible for the enhanced protection in bone-marrow-chimeric (BM)-Cnr2-/- mice. Mixed BM-chimeras further revealed that CB2-expressing cells contributed to ECM development. A heterogeneous CD11b+ cell population, containing macrophages and neutrophils, expanded in the Cnr2-/- spleen after infection and expressed macrophage mannose receptors, arginase-1 activity and IL-10.

Also in the Cnr2-/-brain CD11b+ cells that expressed selected anti-inflammatory markers accumulated and expression of inflammatory mediators IFN-γ and TNF-α was reduced.

Finally, the M2-macrophage chemokine CCL17 was identified as essential factor for enhanced survival in the absence of CB2, since CCL17 x Cnr2 double-deficient mice were fully susceptible to ECM.

Thus, targeting CB2 may be promising for the development of alternative treatment regimes of ECM.”

http://www.ncbi.nlm.nih.gov/pubmed/27474745

Selective activation of CB2 receptor improves efferocytosis in cultured macrophages.

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“Recent evidence indicates that the defective ability to clear apoptotic cells by macrophages (efferocytosis) and the resultant apoptotic cells accumulation in atherosclerotic plaques play an important role during the progression of unstable plaques.

The cannabinoid type 2 receptor (CB2), has recently been emerging as a new target to reduce vulnerability and promote stability of plaques, however, the underlying mechanisms have not been studied in detail. In the present study, we investigated whether selective activation of CB2 improves efferocytosis of macrophages.

SIGNIFICANCE:

The selective activation of CB2 improves efferosytosis of normal-cultured and OxLDL-loaded macrophages, which might provide a novel mechanism on how CB2 activation reduces vulnerability and promotes stability of atherosclerotic plaques.”

http://www.ncbi.nlm.nih.gov/pubmed/27474129