Tag Archives: G-Protein coupled receptors

Cellular localization and regulation of receptors and enzymes of the endocannabinoid system in intestinal and systemic inflammation.

Posted on by
Reply

“Surveys suggest that Cannabis provides benefit for people with inflammatory bowel disease.

However, mechanisms underlying beneficial effects are not clear. We performed in situ hybridization RNAscope® combined with immunohistochemistry to show cell-specific distribution and regulation of cannabinoid receptor 1 and 2 (CB1, CB2), G protein-coupled receptor 55 (GPR55), and monoacylglycerol lipase (MGL) mRNA in immune cells using murine models of intestinal and systemic inflammation.

In summary, our study reveals changes in gene expression of members of the endocannabinoid system in situ attesting particularly GPR55 and MGL a distinct cellular role in the regulation of the immune response to intestinal and systemic inflammation.”

https://www.ncbi.nlm.nih.gov/pubmed/30196316

https://link.springer.com/article/10.1007%2Fs00418-018-1719-0

Δ9-tetrahydrocannabivarin impairs epithelial calcium transport through inhibition of TRPV5 and TRPV6.

Posted on by
Reply

 Pharmacological Research

“Compounds extracted from the cannabis plant, including the psychoactive Δ9-tetrahydrocannabinol (THC) and related phytocannabinoids, evoke multiple diverse biological actions as ligands of the G protein-coupled cannabinoid receptors CB1 and CB2. In addition, there is increasing evidence that phytocannabinoids also have non-CB targets, including several ion channels of the transient receptor potential superfamily.

We investigated the effects of six non-THC phytocannabinoids on the epithelial calcium channels TRPV5 and TRPV6, and found that one of them, Δ9-tetrahydrocannabivarin (THCV), exerted a strong and concentration-dependent inhibitory effect on mammalian TRPV5 and TRPV6 and on the single zebrafish orthologue drTRPV5/6. Moreover, THCV attenuated the drTRPV5/6-dependent ossification in zebrafish embryos in vivo. Oppositely, 11-hydroxy-THCV (THCV-OH), a product of THCV metabolism in mammals, stimulated drTRPV5/6-mediated Ca2+ uptake and ossification.

These results identify the epithelial calcium channels TRPV5 and TRPV6 as novel targets of phytocannabinoids, and suggest that THCV-containing products may modulate TRPV5- and TRPV6-dependent epithelial calcium transport.”

https://www.ncbi.nlm.nih.gov/pubmed/30170189

https://linkinghub.elsevier.com/retrieve/pii/S1043661818311095

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

Posted on by
Reply

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

GPR55 signalling promotes proliferation of pancreatic cancer cells and tumour growth in mice, and its inhibition increases effects of gemcitabine

Posted on by
Reply

Image result for oncogene

“The life expectancy for pancreatic cancer patients has seen no substantial changes in the last 40 years as very few and mostly just palliative treatments are available. As the five years survival rate remains around 5%, the identification of novel pharmacological targets and development of new therapeutic strategies are urgently needed.

Here we demonstrate that inhibition of the G protein-coupled receptor GPR55, using genetic and pharmacological approaches, reduces pancreatic cancer cell growth in vitro and in vivo and we propose that this may represent a novel strategy to inhibit pancreatic ductal adenocarcinoma (PDAC) progression.

Specifically, we show that genetic ablation of Gpr55 in the KRASWT/G12D/TP53WT/R172H/Pdx1-Cre+/+ (KPC) mouse model of PDAC significantly prolonged survival.

Importantly, KPC mice treated with a combination of the GPR55 antagonist Cannabidiol (CBD) and gemcitabine (GEM, one of the most used drugs to treat PDAC), survived nearly three times longer compared to mice treated with vehicle or GEM alone.

Mechanistically, knockdown or pharmacologic inhibition of GPR55 reduced anchorage-dependent and independent growth, cell cycle progression, activation of mitogen-activated protein kinase (MAPK) signalling and protein levels of ribonucleotide reductases in PDAC cells. Consistent with this, genetic ablation of Gpr55 reduced proliferation of tumour cells, MAPK signalling and ribonucleotide reductase M1 levels in KPC mice.

Combination of CBD and GEM inhibited tumour cell proliferation in KPC mice and it opposed mechanisms involved in development of resistance to GEM in vitro and in vivo. Finally, we demonstrate that the tumour suppressor p53 regulates GPR55 protein expression through modulation of the microRNA miR34b-3p.

Our results demonstrate the important role played by GPR55 downstream of p53 in PDAC progression. Moreover our data indicate that combination of CBD and GEM, both currently approved for medical use, might be tested in clinical trials as a novel promising treatment to improve PDAC patients’ outcome.”

https://www.nature.com/articles/s41388-018-0390-1

“Cannabinoid improves survival rates of mice with pancreatic cancer”  https://medicalxpress.com/news/2018-07-cannabinoid-survival-mice-pancreatic-cancer.html

“Study: CBD From Marijuana Plus Chemotherapy Tripled Cancer Survival Rates In Mice” https://www.forbes.com/sites/daviddisalvo/2018/07/31/study-cbd-from-marijuana-plus-chemotherapy-triples-cancer-survival-rates-in-mice/#491942d44630

“Cannabis drug may help pancreatic-cancer patients live almost THREE TIMES longer, study finds” http://www.dailymail.co.uk/health/article-6007275/Cannabis-drug-help-pancreatic-cancer-patients-live-THREE-TIMES-longer-study-finds.html

“Substance in cannabis ‘could boost pancreatic cancer treatments’. Scientists say cannabidiol could extend patients’ lives by a matter of years”  https://www.theguardian.com/science/2018/jul/30/substance-in-cannabis-could-boost-pancreatic-cancer-treatments

“Cannabinoid mice trial holds hope for pancreatic cancer patients”  https://www.smh.com.au/national/cannabinoid-mice-trial-holds-hope-for-pancreatic-cancer-patients-20180731-p4zuls.html

“Medical cannabis extract could help pancreatic cancer patients live longer, early study suggests” https://www.independent.co.uk/news/health/pancreatic-cancer-medical-cannabis-cbd-oil-cannabidiol-chemotherapy-a8470406.html

“Cancer ‘remarkable’ treatment – cannabis CBD could improve survival rate by THREE times. CANCER symptoms could be prevented with a “remarkable” new treatment, which includes cannabis CBD, scientists have revealed. Pancreatic cancer survival rates could be improved by three times, by adding CBD into chemotherapy treatments, they said.” https://www.express.co.uk/life-style/health/996657/cancer-treatment-pancreatic-symptoms-cannabis-cbd

“Compound in cannabis could help pancreatic cancer patients live significantly longer” https://www.deccanchronicle.com/lifestyle/health-and-wellbeing/310718/compound-in-cannabis-could-help-pancreatic-cancer-patients-live-signif.html

Chronic treatment with the phytocannabinoid Cannabidivarin (CBDV) rescues behavioural alterations and brain atrophy in a mouse model of Rett syndrome.

Posted on by
Reply

Neuropharmacology

“Rett syndrome (RTT) is a rare neurodevelopmental disorder, characterized by severe behavioural and physiological symptoms. RTT is caused by mutations in the MECP2 gene in about 95% of cases and to date no cure is available.

The endocannabinoid system modulates several physiological processes and behavioural responses that are impaired in RTT and its deregulation has been associated with neuropsychiatric disorders which have symptoms in common with RTT.

The present study evaluated the potential therapeutic efficacy for RTT of cannabidivarin (CBDV), a non-psychotropic phytocannabinoid from Cannabis sativa that presents antagonistic properties on the G protein-coupled receptor 55 (GPR55), the most recently identified cannabinoid receptor.

Present results demonstrate that systemic treatment with CBDV (2, 20, 100 mg/Kg ip for 14 days) rescues behavioural and brain alterations in MeCP2-308 male mice, a validated RTT model. The CBDV treatment restored the compromised general health status, the sociability and the brain weight in RTT mice. A partial restoration of motor coordination was also observed. Moreover, increased levels of GPR55 were found in RTT mouse hippocampus, suggesting this G protein-coupled receptor as new potential target for the treatment of this disorder.

Present findings highlight for the first time for RTT the translational relevance of CBDV, an innovative therapeutic agent that is under active investigation in the clinical setting.”

 https://www.ncbi.nlm.nih.gov/pubmed/30056123
https://www.sciencedirect.com/science/article/pii/S0028390818304131?via%3Dihub

[Should ophtalmologists recommend medical cannabis to patients with glaucoma?]

Posted on by
Reply

 Image result for ugeskr laeger

“Cannabis has been widely used for various medical purposes since before year 2000 BC. Its effects are mediated by cannabinoids and stimulation of mainly G-protein coupled cannabinoid receptors.

In 1971, subjects who smoked marihuana, showed a decrease in the intraocular pressure.

Later investigations additionally revealed a neuroprotective effect of both ∆-9-tetrahydrocannabinol and cannabidiol (CBD).

Furthermore, CBD was found to promote neurogenesis. The aim of this review is to provide an overview of the potential use of cannabinoids in the treatment of glaucoma.”

https://www.ncbi.nlm.nih.gov/pubmed/30020072

GPR3, GPR6, and GPR12 as novel molecular targets: their biological functions and interaction with cannabidiol.

Posted on by
Reply

Image result for APS journal

“The G protein-coupled receptors 3, 6, and 12 (GPR3, GPR6, and GPR12) comprise a family of closely related orphan receptors with no confirmed endogenous ligands. These receptors are constitutively active and capable of signaling through G protein-mediated and non-G protein-mediated mechanisms. These orphan receptors have previously been reported to play important roles in many normal physiological functions and to be involved in a variety of pathological conditions.

Although they are orphans, GPR3, GPR6, and GPR12 are phylogenetically most closely related to the cannabinoid receptors. Using β-arrestin2 recruitment and cAMP accumulation assays, we recently found that the nonpsychoactive phytocannabinoid cannabidiol (CBD) is an inverse agonist for GPR3, GPR6, and GPR12.

This discovery highlights these orphan receptors as potential new molecular targets for CBD, provides novel mechanisms of action, and suggests new therapeutic uses of CBD for illnesses such as Alzheimer’s disease, Parkinson’s disease, cancer, and infertility. Furthermore, identification of CBD as a new inverse agonist for GPR3, GPR6, and GPR12 provides the initial chemical scaffolds upon which potent and efficacious agents acting on these receptors can be developed, with the goal of developing chemical tools for studying these orphan receptors and ultimately new therapeutic agents.”

https://www.ncbi.nlm.nih.gov/pubmed/29941868

https://www.nature.com/articles/s41401-018-0031-9

Activation of GPR55 increases neural stem cell proliferation and promotes early adult hippocampal neurogenesis

Posted on by
Reply

British Journal of Pharmacology banner

“The cannabinoid system exerts functional regulation of neural stem cell (NSC) proliferation and adult neurogenesis, yet not all effects of cannabinoid-like compounds seen can be attributed to the cannabinoid 1 receptor (CB1 R) or cannabinoid 2 receptor (CB2 R).

The recently de-orphaned GPR55 has been shown to be activated by numerous cannabinoid ligands suggesting that GPR55 is a third cannabinoid receptor.

Here we examined the role of GPR55 activation in NSC proliferation and early adult neurogenesis.

CONCLUSIONS AND IMPLICATIONS:

Together, these findings suggest GPR55 activation as a novel target and strategy to regulate NSC proliferation and adult neurogenesis.”

https://www.ncbi.nlm.nih.gov/pubmed/29888782

https://bpspubs.onlinelibrary.wiley.com/doi/abs/10.1111/bph.14387

“The orphan receptor GPR55 is a novel cannabinoid receptor”  https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2095107/

Localization of cannabinoid receptors CB1, CB2, GPR55, and PPARα in the canine gastrointestinal tract.

Posted on by
Reply

Histochemistry and Cell Biology

“The endocannabinoid system (ECS) is composed of cannabinoid receptors, their endogenous ligands, and the enzymes involved in endocannabinoid turnover.

Modulating the activity of the ECS may influence a variety of physiological and pathophysiological processes.

A growing body of evidence indicates that activation of cannabinoid receptors by endogenous, plant-derived, or synthetic cannabinoids may exert beneficial effects on gastrointestinal inflammation and visceral pain.

The present ex vivo study aimed to investigate immunohistochemically the distribution of cannabinoid receptors CB1, CB2, G protein-coupled receptor 55 (GPR55), and peroxisome proliferation activation receptor alpha (PPARα) in the canine gastrointestinal tract.

Cannabinoid receptors showed a wide distribution in the gastrointestinal tract of the dog.

Since cannabinoid receptors have a protective role in inflammatory bowel disease, the present research provides an anatomical basis supporting the therapeutic use of cannabinoid receptor agonists in relieving motility disorders and visceral hypersensitivity in canine acute or chronic enteropathies.”

https://www.ncbi.nlm.nih.gov/pubmed/29882158

https://link.springer.com/article/10.1007%2Fs00418-018-1684-7

Methods to Quantify Cell Signaling and GPCR Receptor Ligand Bias: Characterization of Drugs that Target the Endocannabinoid Receptors in Huntington’s Disease.

Posted on by
Reply

Huntington’s Disease

“G protein-coupled receptors (GPCRs) interact with multiple intracellular effector proteins such that different ligands may preferentially activate one signal pathway over others, a phenomenon known as signaling bias. Signaling bias can be quantified to optimize drug selection for preclinical research.

Here, we describe moderate-throughput methods to quantify signaling bias of known and novel compounds. In the example provided, we describe a method to define cannabinoid-signaling bias in a cell culture model of Huntington’s disease (HD).

Decreasing type 1 cannabinoid receptor (CB1) levels is correlated with chorea and cognitive deficits in HD. There is evidence that elevating CB1 levels and/or signaling may be beneficial for HD patients while decreasing CB1 levels and/or signaling may be detrimental.

Recent studies have found that Gαi/o-biased CB1 agonists activate extracellular signal-regulated kinase (ERK), increase CB1 protein levels, and improve viability of cells expressing mutant huntingtin. In contrast, CB1 agonists that are β-arrestin1-biased were found to reduce CB1 protein levels and cell viability.

Measuring agonist bias of known and novel CB1 agonists will provide important data that predict CB1-specific agonists that might be beneficial in animal models of HD and, following animal testing, in HD patients. This method can also be applied to study signaling bias for other GPCRs.”

https://www.ncbi.nlm.nih.gov/pubmed/29856035

https://link.springer.com/protocol/10.1007%2F978-1-4939-7825-0_25