Category Archives: Obesity

Modulation of L-α-lysophosphatidylinositol/GPR55 mitogen-activated protein kinase (MAPK) signaling by cannabinoids.

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“This study has implications for developing new therapeutics for the treatment of cancer, pain, and metabolic disorders.

GPR55 is activated by l-α-lysophosphatidylinositol (LPI) but also by certain cannabinoids.

In this study, we investigated the GPR55 pharmacology of various cannabinoids, including analogues of the CB1 receptor antagonist Rimonabant®, CB2 receptor agonists, and Cannabis sativa constituents.

Here, we show that CB1 receptor antagonists can act both as agonists alone and as inhibitors of LPI signaling under the same assay conditions. This study clarifies the controversy surrounding the GPR55-mediated actions of SR141716A; some reports indicate the compound to be an agonist and some report antagonism. In contrast, we report that the CB2 ligand GW405833 behaves as a partial agonist of GPR55 alone and enhances LPI signaling. GPR55 has been implicated in pain transmission, and thus our results suggest that this receptor may be responsible for some of the antinociceptive actions of certain CB2 receptor ligands.

Here, we report that the little investigated cannabis constituents CBDV, CBGA, and CBGV are potent inhibitors of LPI-induced GPR55 signaling.

The phytocannabinoids Δ9-tetrahydrocannabivarin, cannabidivarin, and cannabigerovarin are also potent inhibitors of LPI.

Our findings also suggest that GPR55 may be a new pharmacological target for the following C. sativa constituents: Δ9-THCV, CBDV, CBGA, and CBGV.

These Cannabis sativa constituents may represent novel therapeutics targeting GPR55.”  http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3249141/

“Lysophosphatidylinositol (LPI) is a bioactive lipid generated by phospholipase A2 which is believed to play an important role in several diseases.”  http://www.ncbi.nlm.nih.gov/pubmed/22285325

 “The putative cannabinoid receptor GPR55 promotes cancer cell proliferation.  In this issue of Oncogene, two groups demonstrated that GPR55 is expressed in various cancer types in an aggressiveness-related manner, suggesting a novel cancer biomarker and a potential therapeutic target.” http://www.ncbi.nlm.nih.gov/pubmed/21057532
“The orphan G protein-coupled receptor GPR55 promotes cancer cell proliferation via ERK. These findings reveal the importance of GPR55 in human cancer, and suggest that it could constitute a new biomarker and therapeutic target in oncology.” http://www.ncbi.nlm.nih.gov/pubmed/20818416
“The putative cannabinoid receptor GPR55 defines a novel autocrine loop in cancer cell proliferation. These findings may have important implications for LPI as a novel cancer biomarker and for its receptor GPR55 as a potential therapeutic target.”  http://www.ncbi.nlm.nih.gov/pubmed/20838378
“L-α-lysophosphatidylinositol meets GPR55: a deadly relationship. Evidence points to a role of L-α-lysophosphatidylinositol (LPI) in cancer.”  http://www.ncbi.nlm.nih.gov/pubmed/21367464

Association between cerebral cannabinoid 1 receptor availability and body mass index in patients with food intake disorders and healthy subjects: a [18F]MK-9470 PET study.

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“Although of great public health relevance, the mechanisms underlying disordered eating behavior and body weight regulation remain insufficiently understood.

Compelling preclinical evidence corroborates a critical role of the endocannabinoid system (ECS) in the central regulation of appetite and food intake.  However, in vivo human evidence on ECS functioning in brain circuits involved in food intake regulation as well as its relationship with body weight is lacking, both in health and disease.

Here, we measured cannabinoid 1 receptor (CB1R) availability using positron emission tomography (PET) with [18F]MK-9470 in 54 patients with food intake disorders (FID) covering a wide body mass index (BMI) range (anorexia nervosa, bulimia nervosa, functional dyspepsia with weight loss and obesity; BMI range=12.5-40.6 kg/m2) and 26 age-, gender- and average BMI-matched healthy subjects (BMI range=18.5-26.6 kg/m2).

The association between regional CB1R availability and BMI was assessed within predefined homeostatic and reward-related regions of interest using voxel-based linear regression analyses. CB1R availability was inversely associated with BMI in homeostatic brain regions such as the hypothalamus and brainstem areas in both patients with FID and healthy subjects. However, in FID patients, CB1R availability was also negatively correlated with BMI throughout the mesolimbic reward system (midbrain, striatum, insula, amygdala and orbitofrontal cortex), which constitutes the key circuit implicated in processing appetitive motivation and hedonic value of perceived food rewards.

Our results indicate that the cerebral homeostatic CB1R system is inextricably linked to BMI, with additional involvement of reward areas under conditions of disordered body weight.”

http://www.ncbi.nlm.nih.gov/pubmed/27404285

Cannabinoid receptor 2 as anti-obesity target: inflammation, fat storage and browning modulation.

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“Obesity is associated with a low-grade inflammatory state, and adipocyte hyperplasia/hypertrophy.

Obesity inhibits the “browning” of white adipose tissue.

Cannabinoid receptor 2 (CB2) agonists reduce food intake and induce anti-obesity effect in mice.

CB2 receptor is a novel pharmacological target that should be considered for obesity.”

http://www.ncbi.nlm.nih.gov/pubmed/27294325

http://www.thctotalhealthcare.com/category/obesity-2/

Modulation of cellular redox homeostasis by the endocannabinoid system

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“The endocannabinoid system (ECS) and reactive oxygen species (ROS) constitute two key cellular signalling systems that participate in the modulation of diverse cellular functions.

Importantly, growing evidence suggests that cross-talk between these two prominent signalling systems acts to modulate functionality of the ECS as well as redox homeostasis in different cell types…

To conclude, there is growing appreciation that the ECS may play an important role in the regulation of cellular redox homeostasis…

Indeed, the studies highlighted in this review show that ECS function can impact upon free radical production in a number of different ways.

Crucially, given the importance of redox status in the development of numerous pathologies, these findings identify ECS components as potential therapeutic targets for the treatment of oxidative stress-related neurological, cardiovascular and metabolic disorders.”

http://rsob.royalsocietypublishing.org/content/6/4/150276

ENDOCANNABINOID SYSTEM: A multi-facet therapeutic target.

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“Cannabis sativa is also popularly known as marijuana. It is being cultivated and used by man for recreational and medicinal purposes from many centuries.

Study of cannabinoids was at bay for very long time and its therapeutic value could not be adequately harnessed due to its legal status as proscribed drug in most of the countries.

The research of drugs acting on endocannabinoid system has seen many ups and down in recent past. Presently, it is known that endocannabinoids has role in pathology of many disorders and they also serve “protective role” in many medical conditions.

Several diseases like emesis, pain, inflammation, multiple sclerosis, anorexia, epilepsy, glaucoma, schizophrenia, cardiovascular disorders, cancer, obesity, metabolic syndrome related diseases, Parkinson’s disease, Huntington’s disease, Alzheimer’s disease and Tourette’s syndrome could possibly be treated by drugs modulating endocannabinoid system.

Presently, cannabinoid receptor agonists like nabilone and dronabinol are used for reducing the chemotherapy induced vomiting. Sativex (cannabidiol and THC combination) is approved in the UK, Spain and New Zealand to treat spasticity due to multiple sclerosis. In US it is under investigation for cancer pain, another drug Epidiolex (cannabidiol) is also under investigation in US for childhood seizures. Rimonabant, CB1 receptor antagonist appeared as a promising anti-obesity drug during clinical trials but it also exhibited remarkable psychiatric side effect profile. Due to which the US Food and Drug Administration did not approve Rimonabant in US. It sale was also suspended across the EU in 2008.

Recent discontinuation of clinical trial related to FAAH inhibitor due to occurrence of serious adverse events in the participating subjects could be discouraging for the research fraternity. Despite of some mishaps in clinical trials related to drugs acting on endocannabinoid system, still lot of research is being carried out to explore and establish the therapeutic targets for both cannabinoid receptor agonists and antagonists.

One challenge is to develop drugs that target only cannabinoid receptors in a particular tissue and another is to invent drugs that acts selectively on cannabinoid receptors located outside the blood brain barrier. Besides this, development of the suitable dosage forms with maximum efficacy and minimum adverse effects is also warranted.

Another angle to be introspected for therapeutic abilities of this group of drugs is non-CB1 and non-CB2 receptor targets for cannabinoids.

In order to successfully exploit the therapeutic potential of endocannabinoid system, it is imperative to further characterize the endocannabinoid system in terms of identification of the exact cellular location of cannabinoid receptors and their role as “protective” and “disease inducing substance”, time-dependent changes in the expression of cannabinoid receptors.”

http://www.ncbi.nlm.nih.gov/pubmed/27086601

Cannabidiol promotes browning in 3T3-L1 adipocytes.

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“Recruitment of the brown-like phenotype in white adipocytes (browning) and activation of existing brown adipocytes are currently being investigated as a means to combat obesity.

The present study was designed to investigate the effects of cannabidiol (CBD), a major nonpsychotropic phytocannabinoid of Cannabis sativa, on induction of browning in 3T3-L1 adipocytes.

These data suggest possible roles for CBD in browning of white adipocytes, augmentation of lipolysis, thermogenesis, and reduction of lipogenesis.

In conclusion, the current data suggest that CBD plays dual modulatory roles in the form of inducing the brown-like phenotype as well as promoting lipid metabolism.

Thus, CBD may be explored as a potentially promising therapeutic agent for the prevention of obesity.”

http://www.ncbi.nlm.nih.gov/pubmed/27067870

http://www.thctotalhealthcare.com/category/obesity-2/

Orexin-A represses satiety-inducing POMC neurons and contributes to obesity via stimulation of endocannabinoid signaling.

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“In the hypothalamic arcuate nucleus (ARC), proopiomelanocortin (POMC) neurons and the POMC-derived peptide α-melanocyte-stimulating hormone (α-MSH) promote satiety. POMC neurons receive orexin-A (OX-A)-expressing inputs and express both OX-A receptor type 1 (OX-1R) and cannabinoid receptor type 1 (CB1R) on the plasma membrane.

OX-A is crucial for the control of wakefulness and energy homeostasis and promotes, in OX-1R-expressing cells, the biosynthesis of the endogenous counterpart of marijuana’s psychotropic and appetite-inducing component Δ9-tetrahydrocannabinol, i.e., the endocannabinoid 2-arachidonoylglycerol (2-AG), which acts at CB1R.

We report that OX-A/OX-1R signaling at POMC neurons promotes 2-AG biosynthesis, hyperphagia, and weight gain by blunting α-MSH production via CB1R-induced and extracellular-signal-regulated kinase 1/2 activation- and STAT3 inhibition-mediated suppression ofPomcgene transcription. Because the systemic pharmacological blockade of OX-1R by SB334867 caused anorectic effects by reducing food intake and body weight, our results unravel a previously unsuspected role for OX-A in endocannabinoid-mediated promotion of appetite by combining OX-induced alertness with food seeking. Notably, increased OX-A trafficking was found in the fibers projecting to the ARC of obese mice (ob/oband high-fat diet fed) concurrently with elevation of OX-A release in the cerebrospinal fluid and blood of mice.

Furthermore, a negative correlation between OX-A and α-MSH serum levels was found in obese mice as well as in human obese subjects (body mass index > 40), in combination with elevation of alanine aminotransferase and γ-glutamyl transferase, two markers of fatty liver disease.

These alterations were counteracted by antagonism of OX-1R, thus providing the basis for a therapeutic treatment of these diseases.”

http://www.ncbi.nlm.nih.gov/pubmed/27071101

An Increase in the Omega-6/Omega-3 Fatty Acid Ratio Increases the Risk for Obesity.

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“In the past three decades, total fat and saturated fat intake as a percentage of total calories has continuously decreased in Western diets, while the intake of omega-6 fatty acid increased and the omega-3 fatty acid decreased, resulting in a large increase in the omega-6/omega-3 ratio from 1:1 during evolution to 20:1 today or even higher.

This change in the composition of fatty acids parallels a significant increase in the prevalence of overweight and obesity.

Experimental studies have suggested that omega-6 and omega-3 fatty acids elicit divergent effects on body fat gain through mechanisms of adipogenesis, browning of adipose tissue, lipid homeostasis, brain-gut-adipose tissue axis, and most importantly systemic inflammation.

Prospective studies clearly show an increase in the risk of obesity as the level of omega-6 fatty acids and the omega-6/omega-3 ratio increase in red blood cell (RBC) membrane phospholipids, whereas high omega-3 RBC membrane phospholipids decrease the risk of obesity.

Recent studies in humans show that in addition to absolute amounts of omega-6 and omega-3 fatty acid intake, the omega-6/omega-3 ratio plays an important role in increasing the development of obesity via both AA eicosanoid metabolites and hyperactivity of the cannabinoid system, which can be reversed with increased intake of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA).

A balanced omega-6/omega-3 ratio is important for health and in the prevention and management of obesity.”

http://www.ncbi.nlm.nih.gov/pubmed/26950145

The endocannabinoid system: novel pathway for cardiometabolic Risk-factor reduction.

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“Although rimonabant has been approved for use in several countries, the Food and Drug Administration has expressed concern about the potential for adverse neurologic and psychiatric effects, considering the widespread distribution of CB1 receptors in the brain. While more research is clearly needed, the clinical evidence shows that CB1-receptor blockade with rimonabant improves multiple cardiovascular and metabolic variables, including body weight and waist circumference, HDL-C, triglycerides, and glucose metabolism. Furthermore, these effects, which are probably mediated by both peripheral and central actions in the ECS, appear to be greater than the improvements that would be expected from weight loss alone. There are multiple ongoing and planned studies with rimonabant as well as several other CB-receptor blockers (e.g., taranabant, CP-945,598). While diet and exercise are the cornerstones of cardiometabolic risk-factor reduction, improved pharmacotherapies are urgently needed. The ECS has provided us with new insights and a promising new avenue for the management of obesity and its associated cardiometabolic risk factors.”

http://www.ncbi.nlm.nih.gov/pubmed/18047036

The endocannabinoid system: potential for reducing cardiometabolic risk.

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“The endocannabinoid system (ECS) affects multiple metabolic pathways in the brain and other organs. The transmembrane CB receptors were cloned in the early 1990s, followed shortly thereafter by the discovery of endogenous ligands, now known as endocannabinoids.

Three general types of cannabimimetic compounds have been described: herbal CBs, which occur uniquely in the cannabis plant (Cannabis sativa); endogenous CBs (or endocannabinoids), which are produced in the brain and peripheral tissues; and synthetic CBs, which are functionally similar compounds synthesized in the laboratory.

Obesity is associated with increased risk for insulin resistance, type 2 diabetes, nonalcoholic fatty liver disease, atherogenic dyslipidemia, and cardiovascular disease. Recent studies indicate that the body protects itself from weight loss by lowering energy expenditure. Both energy consumption and energy expenditure are regulated by hormones from a number of organs that act on the brain, as well as neural signals emanating from the brain itself.

Lifestyle modification is the initial intervention for obesity, with emphasis on reducing calorie intake and increasing physical activity; pharmacotherapy may be indicated for certain cardiovascular and metabolic risk factors.

This review focuses on the link between the biology of the cannabinoid receptor type 1 (CB1 receptor) system and body-weight regulation, as well as clinical data from studies of the first CB1 receptor antagonist…”

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2905146/