Endogenous and synthetic cannabinoids induce the downregulation of cannabinoid CB1 receptor in retina.

Experimental Eye Research

“Endogenous and synthetic cannabinoids have been shown to provide neuroprotection to retinal neurons in acute animal models of retinopathy.

Chronic exposure to cannabinoid receptor (CB1R) agonists has been reported to induce downregulation of the CB1R in brain and behavioral tolerance.

The aim of this study was to investigate the effect of subchronic/chronic cannabinoid administration on CB1R downregulation in normal rat retina, its downstream prosurvival signaling and subsequent effect on retinal neuroprotection against AMPA excitotoxicity.

This study provides novel information regarding agonist-induced CB1R downregulation in rat retina after subchronic/chronic cannabinoid treatment, and its effect on downstream prosurvival signaling and neuroprotection.”

https://www.ncbi.nlm.nih.gov/pubmed/31199905

https://www.sciencedirect.com/science/article/pii/S0014483519301216?via%3Dihub

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Selective modulation of the cannabinoid type 1 (CB1) receptor as an emerging platform for the treatment of neuropathic pain.

“Neuropathic pain is caused by a lesion or dysfunction in the nervous system, and it may arise from illness, be drug-induced or caused by toxin exposure. Since the discovery of two G-protein-coupled cannabinoid receptors (CB1 and CB2) nearly three decades ago, there has been a rapid expansion in our understanding of cannabinoid pharmacology. This is currently one of the most active fields of neuropharmacology, and interest has emerged in developing cannabinoids and other small molecule modulators of CB1 and CB2 as therapeutics for neuropathic pain. This short review article provides an overview of the chemotypes currently under investigation for the development of novel neuropathic pain treatments targeting CB1 receptors.”

Graphical abstract: Selective modulation of the cannabinoid type 1 (CB1) receptor as an emerging platform for the treatment of neuropathic pain
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Novel CB1-ligands maintain homeostasis of the endocannabinoid-system in ω3- and ω6-long chain-PUFA deficiency.

The Journal of Lipid Research“Mammalian ω3- and ω6-PUFAs are synthesized from essential fatty acids (EFAs) or supplied by the diet. PUFAs are constitutive elements of membrane-architecture and precursors of lipid signaling molecules. EFAs and long chain PUFAs are precursors in the synthesis of endocannabinoid-ligands of the Gi/o-protein coupled cannabinoid receptors 1 and 2 in the endocannabinoid-system, which critically regulates energy homeostasis, as metabolic signaling system in hypothalamic neuronal circuits, and behavioral parameters. We utilized the auxotrophic fatty acid desaturase 2 deficient (fads2-/-) mouse, deficient in long chain PUFA-synthesis, to follow the age dependent dynamics of the PUFA pattern in the CNS-phospholipidome in unbiased dietary studies of three cohorts on sustained long chain PUFA-free, ω6-arachidonic and ω3-docosahexaenoic acid supplemented diets and their impact on the precursor pool of CB1 ligands. We discovered the transformation of eicosa-all cis-5,11,14-trienoic acid, uncommon in mammalian lipidomes, into two novel endocannabinoids, 20:35,11,14-ethanolamide and 2-20:35,11,14-glycerol, acting as ligands of CB1 in HEK293-cells. Labeling experiments excluded a Δ8-desaturase activity and proved the position-specificity of FADS2. The fads2 -/- mutant might serve as an unbiased model in vivo in the development of novel CB1-agonists and antagonists.”

https://www.ncbi.nlm.nih.gov/pubmed/31167809

http://www.jlr.org/content/early/2019/06/05/jlr.M094664

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Countering the Modern Metabolic Disease Rampage With Ancestral Endocannabinoid System Alignment.

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“When primitive vertebrates evolved from ancestral members of the animal kingdom and acquired complex locomotive and neurological toolsets, a constant supply of energy became necessary for their continued survival. To help fulfill this need, the endocannabinoid (eCB) system transformed drastically with the addition of the cannabinoid-1 receptor (CB1R) to its gene repertoire. This established an eCB/CB1R signaling mechanism responsible for governing the whole organism’s energy balance, with its activation triggering a shift toward energy intake and storage in the brain and the peripheral organs (i.e., liver and adipose).

Although this function was of primal importance for humans during their pre-historic existence as hunter-gatherers, it became expendable following the successive lifestyle shifts of the Agricultural and Industrial Revolutions. Modernization of the world has further increased food availability and decreased energy expenditure, thus shifting the eCB/CB1R system into a state of hyperactive deregulated signaling that contributes to the 21st century metabolic disease pandemic.

Studies from the literature supporting this perspective come from a variety of disciplines, including biochemistry, human medicine, evolutionary/comparative biology, anthropology, and developmental biology. Consideration of both biological and cultural evolution justifies the design of improved pharmacological treatments for obesity and Type 2 diabetes (T2D) that focus on peripheral CB1R antagonism. Blockade of peripheral CB1Rs, which universally promote energy conservation across the vertebrate lineage, represents an evolutionary medicine strategy for clinical management of present-day metabolic disorders.”

https://www.ncbi.nlm.nih.gov/pubmed/31156558

https://www.frontiersin.org/articles/10.3389/fendo.2019.00311/full

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Cannabinoid Receptor 1 Blockade Attenuates Obesity and Adipose Tissue Type 1 Inflammation Through miR-30e-5p Regulation of Delta-Like-4 in Macrophages and Consequently Downregulation of Th1 Cells.

 Image result for frontier in immunology“Obesity is characterized by chronic low-grade inflammation that contributes to development of cardiometabolic disorders. Cannabinoid receptor 1 (CB1) antagonists attenuate diet-induced obesity (DIO) and related inflammation, although the precise anti-inflammatory mechanisms involved have not been fully explored. In the current study we used a mouse model of DIO intervention to determine the microRNA (miRNA, miR)-mediated anti-obesity and anti-inflammatory effects of the CB1 antagonist, AM251. DIO mice that were fed high-fat diet (HFD) for 12 weeks were treated with AM251 (10 mg/kg) for an additional 4 weeks. HFD + AM251 mice experienced rapid and prolonged weight loss and reduced inflammatory M1 adipose tissue macrophage (ATM) infiltration. To investigate miRNA-mediated regulation of ATMs, F4/80+ cells from stromal vascular fractions (SVF) of epididymal fat were subjected to miR microarray analysis. Several miRs were differentially expressed in AM251-treated mice that were independent of calorie restriction. Prominently, miR-30e-5p was upregulated in ATMs from HFD + AM251 mice while the miR-30e-5p target, DLL4, was downregulated. Consistent with a decrease in DLL4-Notch signaling, fat storage and pro-inflammatory cytokine/chemokine expression was reduced following AM251 treatment. Furthermore, we found that AM251-treated macrophages can suppress DLL4-mediated Th1 polarization in CD4+ T cells. Together these data demonstrate that blocking CB1 receptors leads to upregulation of miR-30e-5p and down regulation of DLL4 in ATMs, which in turn suppress DLL4-Notch signaling-induced polarization of inflammatory Th1 cells and adipocyte energy storage. This combined effect of ATMs and T cells leads to an anti-inflammatory state and attenuation of DIO. These data support therapeutic potential of miR-30 in the treatment of cardiometabolic disorders.”

https://www.ncbi.nlm.nih.gov/pubmed/31134094

https://www.frontiersin.org/articles/10.3389/fimmu.2019.01049/full

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Retrograde activation of CB1R by muscarinic receptors protects against central organophosphorus toxicity.

Neuropharmacology“The acute toxicity of organophosphorus-based compounds is primarily a result of acetylcholinesterase inhibition in the central and peripheral nervous systems. The resulting cholinergic crisis manifests as seizure, paralysis, respiratory failure and neurotoxicity. Though overstimulation of muscarinic receptors is the mechanistic basis of central organophosphorus (OP) toxicities, short-term changes in synapse physiology that precede OP-induced seizures have not been investigated in detail. To study acute effects of OP exposure on synaptic function, field excitatory postsynaptic potentials (fEPSPs) were recorded from Schaffer collateral synapses in the mouse hippocampus CA1 stratum radiatum during perfusion with various OP compounds. Administration of the OPs paraoxon, soman or VX rapidly and stably depressed fEPSPs via a presynaptic mechanism, while the non-OP proconvulsant tetramethylenedisulfotetramine had no effect on fEPSP amplitudes. OP-induced presynaptic long-term depression manifested prior to interictal spiking, occurred independent of recurrent firing, and did not require NMDA receptor currents, suggesting that it was not mediated by activity-dependent calcium uptake. Pharmacological dissection revealed that the presynaptic endocannabinoid type 1 receptor (CB1R) as well as postsynaptic M1 and M3 muscarinic acetylcholine receptors were necessary for OP-LTD. Administration of CB1R antagonists significantly reduced survival in mice after a soman challenge, revealing an acute protective role for endogenous CB1R signaling during OP exposure. Collectively these data demonstrate that the endocannabinoid system alters glutamatergic synaptic function during the acute response to OP acetylcholinesterase inhibitors.”

https://www.ncbi.nlm.nih.gov/pubmed/31132436

“CB1R activation represents a novel therapy to mitigate acute OP toxicity”

https://www.sciencedirect.com/science/article/pii/S002839081930190X?via%3Dihub

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5-Chlorobenzofuran-2-carboxamides: From allosteric CB1 modulators to potential apoptotic antitumor agents.

European Journal of Medicinal Chemistry“Cannabinoids as THC and the CB1 allosteric modulator CBD were reported to have antiproliferative activities with no reports for other CB1 allosteric modulators as the 5-chloroindole-2-carboxamide derivatives and their furan congeners. Based on the antiproliferative activity of two 5-chlorobenzofuran-2-carboxamide allosteric CB1 modulators, a series of novel derivatives was designed and synthesized. The synthesized compounds were tested in a cell viability assay using human mammary gland epithelial cell line (MCF-10A) where all the compounds exhibited no cytotoxic effects and more than 85% cell viability at a concentration of 50 μM. Some derivatives showed good antiproliferative activities against tumor cells as compounds 8, 15, 21 and 22. The most active compound 15 showed equipotent activity to doxorubicin. Compounds 7, 9, 15, 16, 21 and 22 increased the level of active caspase 3 by 4-8 folds, compared to the control cells in MCF-7 cell line and doxorubicin as a reference drug. Compounds 15 and 21, the most activecaspase-3 inducers, increase the levels of caspase 8 and 9 indicating activation of both intrinsic and extrinsic pathways and showed potent induction of Bax, down-regulation of Bcl-2 protein levels and over-expression of Cytochrome C levels in MCF-7 cell lines. Compound 15 exhibited cell cycle arrest at the Pre-G1 and G2/M phases in the cell cycle analysis of MCF-7 cell line. The drug Likeness profile of the synthesized compounds showed that all the compounds were predicted to have high oral absorption complying with different pharmacokinetics filters.”

https://www.ncbi.nlm.nih.gov/pubmed/31128433

https://www.sciencedirect.com/science/article/pii/S0223523419304507?via%3Dihub

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Down-Regulation of Cannabinoid Type 1 (CB1) Receptor and its Downstream Signaling Pathways in Metastatic Colorectal Cancer.

 cancers-logo“Changes in the regulation of endocannabinoid production, together with an altered expression of their receptors are hallmarks of cancer, including colorectal cancer (CRC). Although several studies have been conducted to understand the biological role of the CB1 receptor in cancer, little is known about its involvement in the metastatic process of CRC. The aim of this study was to investigate the possible link between CB1 receptor expression and the presence of metastasis in patients with CRC, investigating the main signaling pathways elicited downstream of CB1 receptor in colon cancer. Fifty-nine consecutive patients, with histologically proven colorectal cancer, were enrolled in the study, of which 30 patients with synchronous metastasis, at first diagnosis and 29 without metastasis. A low expression of CB1 receptor were detected in primary tumor tissue of CRC patients with metastasis and consequently, we observed an alteration of CB1 receptor downstream signaling. These signaling routes were also altered in intestinal normal mucosa, suggesting that, normal mucosa surrounding the tumor provides a realistic picture of the molecules involved in tissue malignant transformation. These observations contribute to the idea that drugs able to induce CB1 receptor expression can be helpful in order to set new anticancer therapeutic strategies.”

https://www.ncbi.nlm.nih.gov/pubmed/31121931

https://www.mdpi.com/2072-6694/11/5/708

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Targeting Peripheral CB1 Receptors Reduces Ethanol Intake via a Gut-Brain Axis.

Cell Metabolism

“Endocannabinoids acting on the cannabinoid-1 receptor (CB1R) or ghrelin acting on its receptor (GHS-R1A) both promote alcohol-seeking behavior, but an interaction between the two signaling systems has not been explored. Here, we report that the peripheral CB1R inverse agonist JD5037 reduces ethanol drinking in wild-type mice but not in mice lacking CB1R, ghrelin peptide or GHS-R1A. JD5037 treatment of alcohol-drinking mice inhibits the formation of biologically active octanoyl-ghrelin without affecting its inactive precursor desacyl-ghrelin. In ghrelin-producing stomach cells, JD5037 reduced the level of the substrate octanoyl-carnitine generated from palmitoyl-carnitine by increasing fatty acid β-oxidation. Blocking gastric vagal afferents abrogated the ability of either CB1R or GHS-R1A blockade to reduce ethanol drinking. We conclude that blocking CB1R in ghrelin-producing cells reduces alcohol drinking by inhibiting the formation of active ghrelin and its signaling via gastric vagal afferents. Thus, peripheral CB1R blockade may have therapeutic potential in the treatment of alcoholism.”

https://www.ncbi.nlm.nih.gov/pubmed/31105045

https://www.sciencedirect.com/science/article/pii/S1550413119301962?via%3Dihub

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Role of the endocannabinoid and endovanilloid systems in an animal model of schizophrenia-related emotional processing/cognitive deficit.

Neuropharmacology

“Studies suggest that the endocannabinoid and endovanilloid systems are implicated in the pathophysiology of schizophrenia.

The Spontaneously Hypertensive Rats (SHR) strain displays impaired contextual fear conditioning (CFC) attenuated by antipsychotic drugs and worsened by pro-psychotic manipulations. Therefore, SHR strain is used to study emotional processing/associative learning impairments associated with schizophrenia and effects of potential antipsychotic drugs.

Here, we evaluated the expression of CB1 and TRPV1 receptors in some brain regions related to the pathophysiology of schizophrenia. We also assessed the effects of drugs that act on the endocannabinoid/endovanilloid systems on the CFC task in SHRs and control animals (Wistar rats – WRs).

These results reinforce the involvement of the endocannabinoid/endovanilloid systems in the SHRs CFC deficit and point to these systems as targets to treat the emotional processing/cognitive symptoms of schizophrenia.”

https://www.ncbi.nlm.nih.gov/pubmed/31103618

https://www.sciencedirect.com/science/article/pii/S0028390819301649?via%3Dihub

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