Novel selective antagonist of the cannabinoid CB1 receptor, MJ15, with prominent anti-obesity effect in rodent models (original) (raw)
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Acta Pharmacologica Sinica, 2011
Aim: To characterize the biological profiles of MJ08, a novel selective CB 1 receptor antagonist. Methods: Radioligand binding assays were performed using rat brain and spleen membrane preparations. CB 1 and CB 2 receptor redistribution and intracellular Ca 2+ ([Ca 2+ ] i) assays were performed with IN CELL Analyzer. Inverse agonism was studied using intracellular cAMP assays, and in guinea-pig ileum and mouse vas deferens smooth muscle preparations. In vivo pharmacologic profile was assessed in diet-induced obesity (DIO) mice. Results: In radioligand binding assay, MJ08 selectively antagonized CB 1 receptor (IC 50 =99.9 nmol/L). In EGFP-CB 1 _U2OS cells, its IC 50 value against CB 1 receptor activation was 30.23 nmol/L (SR141716A: 32.16 nmol/L). WIN 55,212-2 (1 μmol/L) increased [Ca 2+ ] i in the primary cultured hippocampal neuronal cells and decreased cAMP accumulation in CHO-hCB 1 cells. MJ08 (10 nmol/L-10 μmol/L) blocked both the WIN 55,212-2-induced effects. Furthermore, MJ08 reversed the inhibition of electrically evoked twitches of mouse vas deferens by WIN 55,212-2 (pA 2 =10.29±1.05). MJ08 and SR141716A both showed an inverse agonism activity by markedly promoting the contraction force and frequency of guinea pig ileum muscle. MJ08 significantly increased the cAMP level in CHO-hCB 1 cells with an EC 50 value of 78.6 nmol/L, which was lower than the EC 50 value for SR141716A (159.2 nmol/L). Besides the more potent pharmacological effects of cannabinoid CB 1 receptor antagonism in DIO mice, such as reducing food intake, decreasing body weight, and ameliorating dyslipidemia, MJ08 (10 mg/kg) unexpectedly raised the fasted blood glucose in vivo. Conclusion: MJ08 is a novel, potent and selective CB 1 receptor antagonist/inverse agonist with potent bioactive responses in vitro and in vivo that may be useful for disclosure the versatile nature of CB 1 receptors.
CANNABINOID RECEPTORS AS THERAPEUTIC TARGETS
Annual Review of Pharmacology and Toxicology, 2006
One of the most interesting pharmacological targets proposed in the past ten years for fighting obesity and related metabolic disorders is the endocannabinoid system. The role of the endocannabinoid system is crucial in regulating the rewarding properties of food, in controlling energy balance by acting at the hypothalamic circuitries involved in food intake, and in peripheral metabolism by influencing adipocytes, hepatocytes, myocytes and pancreatic endocrine cells. Obesity seems to be a condition associated with a pathological overactivation of the endocannabinoid system; therefore, restoring a normal endocannabinoid tone by antagonizing the cannabinoid receptor type 1 (CB 1 ) could help arrest both the development and the maintenance of obesity.
European Journal of Medicinal Chemistry, 2014
Presently, obesity is one of the major health problems in the developed as well as developing countries due to lack of physical work and increasing sedentary life style. Endocannabinoid system (ECS) and especially cannabinoid 1 (CB1) receptor play a key role in energy homeostasis. Food intake and energy storage is enhanced due to the stimulation of ECS hence, inhibition of ECS by blocking CB1 receptors could be a promising approach in the treatment of obesity. Rimonabant, a diaryl pyrazole was the first potent and selective CB1 receptor antagonist that was introduced into the market in 2006 but was withdrawn in 2008 due to its psychiatric side effects. Researchers all over the world are interested to develop peripherally acting potent and selective CB1 receptor antagonists having a better pharmacokinetic profile and therapeutic index. In this development process, pyrazole ring of rimonabant has been replaced by different bioisosteric scaffolds like pyrrole, imidazole, triazole, pyrazoline, pyridine etc. Variations in substituents around the pyrazole ring have also been done. New strategies were also employed for minimizing the psychiatric side effects by making more polar and less lipophilic antagonists/inverse agonists along with neutral antagonists acting peripherally. It has been observed that some of the peripherally acting compounds do not show adverse effects and could be used as potential leads for the further design of selective CB1 receptor antagonists. Chemical modification strategies used for the development of selective CB1 receptor antagonists are discussed here in this review.
Biochemical and Biophysical Research Communications, 2010
Cannabinoid CB 1 receptor antagonists exhibit pharmacologic properties favorable for the treatment of metabolic disease. 598 (1-[9-(4-chlorophenyl)-8-(2-chlorophenyl)-9H-purin-6-yl]-4-ethylamino piperidine-4-carboxylic acid amide hydrochloride) is a recently discovered selective, high affinity, competitive CB 1 receptor antagonist that inhibits both basal and cannabinoid agonist-mediated CB 1 receptor signaling in vitro and in vivo. CP-945,598 exhibits sub-nanomolar potency at human CB 1 receptors in both binding (K i = 0.7 nM) and functional assays (K i = 0.2 nM). The compound has low affinity (K i = 7600 nM) for human CB 2 receptors. In vivo, CP-945,598 reverses four cannabinoid agonist-mediated CNS-driven responses (hypo-locomotion, hypothermia, analgesia, and catalepsy) to a synthetic cannabinoid receptor agonist. CP-945,598 exhibits dose and concentration-dependent anorectic activity in two models of acute food intake in rodents, fast-induced re-feeding and spontaneous, nocturnal feeding. CP-945,598 also acutely stimulates energy expenditure in rats and decreases the respiratory quotient indicating a metabolic switch to increased fat oxidation. CP-945,598 at 10 mg/kg promoted a 9%, vehicle adjusted weight loss in a 10 day weight loss study in diet-induced obese mice. Concentration/effect relationships combined with ex vivo brain CB 1 receptor occupancy data were used to evaluate efficacy in behavioral, food intake, and energy expenditure studies. Together, these in vitro, ex vivo, and in vivo data indicate that CP-945,598 is a novel CB 1 receptor competitive antagonist that may further our understanding of the endocannabinoid system.
Journal of Clinical Investigation, 2010
Obesity and its metabolic consequences are a major public health concern worldwide. Obesity is associated with overactivity of the endocannabinoid system, which is involved in the regulation of appetite, lipogenesis, and insulin resistance. Cannabinoid-1 receptor (CB 1 R) antagonists reduce body weight and improve cardiometabolic abnormalities in experimental and human obesity, but their therapeutic potential is limited by neuropsychiatric side effects. Here we have demonstrated that a CB 1 R neutral antagonist largely restricted to the periphery does not affect behavioral responses mediated by CB 1 R in the brains of mice with genetic or diet-induced obesity, but it does cause weight-independent improvements in glucose homeostasis, fatty liver, and plasma lipid profile. These effects were due to blockade of CB 1 R in peripheral tissues, including the liver, as verified through the use of CB 1 R-deficient mice with or without transgenic expression of CB 1 R in the liver. These results suggest that targeting peripheral CB 1 R has therapeutic potential for alleviating cardiometabolic risk in obese patients.
Cannabinoid receptors as therapeutic targets for obesity and metabolic diseases
Current opinion in pharmacology, 2006
One of the most interesting pharmacological targets proposed in the past ten years for fighting obesity and related metabolic disorders is the endocannabinoid system. The role of the endocannabinoid system is crucial in regulating the rewarding properties of food, in controlling energy balance by acting at the hypothalamic circuitries involved in food intake, and in peripheral metabolism by influencing adipocytes, hepatocytes, myocytes and pancreatic endocrine cells. Obesity seems to be a condition associated with a pathological overactivation of the endocannabinoid system; therefore, restoring a normal endocannabinoid tone by antagonizing the cannabinoid receptor type 1 (CB(1)) could help arrest both the development and the maintenance of obesity.
Journal of Neuroendocrinology, 2008
The endogenous cannabinoid system plays an important modulatory role in feeding behaviour and metabolism, acting at both central and peripheral levels. Chronic administration of cannabinoid CB1 receptor antagonists has been found to be effective in experimental obesity. However, clinically available cannabinoid receptor antagonists are inverse agonists that can target CB1 receptors located in both central circuits regulating appetite and motivation and in peripheral organs regulating metabolism and energy expenditure. This profile complicates understanding of cannabinoid CB1 receptor blockade as a therapeutic strategy in obesity and metabolic disorders. This review aims to explore the relevance of both inverse agonism and peripheral cannabinoid receptor blockade on the beneficial actions of chronic cannabinoid receptor blockade, by comparing the actions of the reference antagonist/inverse agonist rimonabant and the newly designed drug LH-21. LH-21 is a triazol derivative and a neutral cannabinoid receptor antagonist; it has a poor penetration rate into the central nervous system. When given acutely it decreases food intake and enhances the anorectic actions of oleoylethanolamide, a feeding suppressant lipid that acts on peripheral sensory terminals in a similar way as rimonabant. Unlike rimonabant, chronic administration of LH-21 (3 mg/kg) reduces feeding but does not improve hypertriglyceridaemia or hypercholesterolaemia; nor does it reduce liver fat deposits in Zucker rats. These results suggest that the inverse agonism and/or the antagonism of central cannabinoid CB1 receptors are necessary for the metabolic benefits of cannabinoid CB1 receptor blockade, but not for the appetite reduction.
Current Psychiatry Reports, 2007
The endogenous endocannabinoid system encompasses a family of natural signaling lipids ("endocannabinoids") functionally related to Δ 9-tetrahydrocannabinol, the psychoactive ingredient of marijuana (cannabis), along with proteins that modulate the endocannabinoids, including enzymes, transporters, and receptors. The endocannabinoid system's ubiquitous regulatory actions in health and disease underscore its importance to mammalian (patho)physiology and suggest discrete targets through which it may be modulated for therapeutic gain. Medications based on the endocannabinoid system are an important focus of contemporary translational research, particularly with respect to substance abuse and obesity, two prevalent disorders with a pathogenic component of endocannabinoid system hyperactivity. Pressing health care needs have made the rational design of targeted CB1 cannabinoid-receptor modulators a promising route to future medications with significant therapeutic impact against psychobehavioral and metabolic disturbances having a reward-supported appetitive component.
Physiology & Behavior, 2008
Endogenous signaling lipids ("endocannabinoids") functionally related to Δ 9tetrahydrocannabinol, the psychoactive ingredient of marijuana (Cannabis), are important biomediators and metabolic regulators critical to mammalian (patho)physiology. The growing family of endocannabinoids, along with endocannabinoid biosynthetic and inactivating enzymes, transporters, and at least two membrane-bound, G-protein coupled receptors, comprise collectively the mammalian endocannabinoid signaling system. The ubiquitous and diverse regulatory actions of the endocannabinoid system in health and disease have supported the regulatory approval of natural products and synthetic agents as drugs that alter endocannabinoid-system activity. More recent data support the concept that the endocananbinoid system may be modulated for therapeutic gain at discrete pharmacological targets with safety and efficacy. Potential medications based on the endocannabinoid system have thus become a central focus of contemporary translational research for varied indications with important unmet medical needs. One such indication, obesity, is a global pandemic whose etiology has a pathogenic component of endocannabinoid-system hyperactivity and for which current pharmacological treatment is severely limited. Application of high-affinity, selective CB1 cannabinoid receptor ligands to attenuate endocannabinoid signaling represents a state-of-the-art approach for improving obesity pharmacotherapy. To this intent, several selective CB1 receptor antagonists with varied chemical structures are currently in advanced preclinical or clinical trials, and one (rimonabant) has been approved as a weightmanagement drug in some markets. Emerging preclinical data suggest that CB1 receptor neutral antagonists may represent breakthrough medications superior to antagonists/inverse agonists such as rimonabant for therapeutic attenuation of CB1 receptor transmission. Since obesity is a predisposing condition for the cluster of cardiovascular and metabolic derangements collectively known as the metabolic syndrome, effective endocannabinoid-modulatory anti-obesity therapeutics would also help redress other major health problems including type-2 diabetes, atherothrombosis, inflammation, and immune disorders. Pressing worldwide healthcare needs and increasing appreciation of endocannabinoid biology make the rational design and refinement of targeted CB1 receptor modulators a promising route to future medications with significant therapeutic impact against overweight, obesity, obesity-related cardiometabolic dysregulation, and, more generally, maladies having a reward-supported appetitive component.
Obesity and the Endocannabinoid System: Is There Still a Future for CB1 Antagonists in Obesity?
Current Obesity Reports, 2012
The current epidemic of obesity in western countries is being worsened by the lack of effective pharmacotherapies. The apparent success of a central nervous systemacting cannabinoid CB 1 receptor antagonist-based treatment for obesity was hampered by the appearance of psychiatric side effects in certain patients. These adverse effects forced its withdrawal from the market. However, the discovery that the main beneficial metabolic effects of cannabinoid CB 1 receptor antagonists were derived of its activity in peripheral tissues, including the adipose tissue, opened the possibility of rescuing this type of therapy. This goal might be achieved by differential medicinal chemistry approaches. The present review examines these options that include peripheral-restricted cannabinoid CB 1 receptor antagonists, dual ligands and combinatorial therapies using sub-effective doses of CB 1 receptor antagonists that might be devoid of side effects.