Publications by authors named "Resat Cinar"

60 Publications

Effects of a Peripherally Restricted Hybrid Inhibitor of CB1 Receptors and iNOS on Alcohol Drinking Behavior and Alcohol-Induced Endotoxemia.

Molecules 2021 Aug 22;26(16). Epub 2021 Aug 22.

Laboratory of Physiologic Studies, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD 20892, USA.

Alcohol consumption is associated with gut dysbiosis, increased intestinal permeability, endotoxemia, and a cascade that leads to persistent systemic inflammation, alcoholic liver disease, and other ailments. Craving for alcohol and its consequences depends, among other things, on the endocannabinoid system. We have analyzed the relative role of central vs. peripheral cannabinoid CB1 receptors (CB1R) using a "two-bottle" as well as a "drinking in the dark" paradigm in mice. The globally acting CB1R antagonist rimonabant and the non-brain penetrant CB1R antagonist JD5037 inhibited voluntary alcohol intake upon systemic but not upon intracerebroventricular administration in doses that elicited anxiogenic-like behavior and blocked CB1R-induced hypothermia and catalepsy. The peripherally restricted hybrid CB1R antagonist/iNOS inhibitor -MRI-1867 was also effective in reducing alcohol consumption after oral gavage, while its enantiomer (CB1R inactive/iNOS inhibitor) was not. The two MRI-1867 enantiomers were equally effective in inhibiting an alcohol-induced increase in portal blood endotoxin concentration that was caused by increased gut permeability. We conclude that (i) activation of peripheral CB1R plays a dominant role in promoting alcohol intake and (ii) the iNOS inhibitory function of MRI-1867 helps in mitigating the alcohol-induced increase in endotoxemia.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3390/molecules26165089DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8399901PMC
August 2021

CB R and iNOS are distinct players promoting pulmonary fibrosis in Hermansky-Pudlak syndrome.

Clin Transl Med 2021 Jul;11(7):e471

Section of Human Biochemical Genetics, Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland, USA.

Hermansky-Pudlak syndrome (HPS) is a rare genetic disorder which, in its most common and severe form, HPS-1, leads to fatal adult-onset pulmonary fibrosis (PF) with no effective treatment. We evaluated the role of the endocannabinoid/CB R system and inducible nitric oxide synthase (iNOS) for dual-target therapeutic strategy using human bronchoalveolar lavage fluid (BALF), lung samples from patients with HPS and controls, HPS-PF patient-derived lung fibroblasts, and bleomycin-induced PF in pale ear mice (HPS1 ). We found overexpression of CB R and iNOS in fibrotic lungs of HPSPF patients and bleomycin-infused pale ear mice. The endocannabinoid anandamide was elevated in BALF and negatively correlated with pulmonary function parameters in HPSPF patients and pale ear mice with bleomycin-induced PF. Simultaneous targeting of CB R and iNOS by MRI-1867 yielded greater antifibrotic efficacy than inhibiting either target alone by attenuating critical pathologic pathways. Moreover, MRI-1867 treatment abrogated bleomycin-induced increases in lung levels of the profibrotic interleukin-11 via iNOS inhibition and reversed mitochondrial dysfunction via CB R inhibition. Dual inhibition of CB R and iNOS is an effective antifibrotic strategy for HPSPF.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/ctm2.471DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8255071PMC
July 2021

National Institutes of Health Consensus Development Project on Criteria for Clinical Trials in Chronic Graft-versus-Host Disease: IV. The 2020 Highly morbid forms report.

Transplant Cell Ther 2021 Jun 10. Epub 2021 Jun 10.

Clinical Research Division, Fred Hutchinson Cancer Research Center, Seattle, Washington; Department of Medicine, University of Washington, Seattle, Washington.

Chronic graft-versus-host disease (GVHD) can be associated with significant morbidity, in part because of nonreversible fibrosis, which impacts physical functioning (eye, skin, lung manifestations) and mortality (lung, gastrointestinal manifestations). Progress in preventing severe morbidity and mortality associated with chronic GVHD is limited by a complex and incompletely understood disease biology and a lack of prognostic biomarkers. Likewise, treatment advances for highly morbid manifestations remain hindered by the absence of effective organ-specific approaches targeting "irreversible" fibrotic sequelae and difficulties in conducting clinical trials in a heterogeneous disease with small patient numbers. The purpose of this document is to identify current gaps, to outline a roadmap of research goals for highly morbid forms of chronic GVHD including advanced skin sclerosis, fasciitis, lung, ocular and gastrointestinal involvement, and to propose strategies for effective trial design. The working group made the following recommendations: (1) Phenotype chronic GVHD clinically and biologically in future cohorts, to describe the incidence, prognostic factors, mechanisms of organ damage, and clinical evolution of highly morbid conditions including long-term effects in children; (2) Conduct longitudinal multicenter studies with common definitions and research sample collections; (3) Develop new approaches for early identification and treatment of highly morbid forms of chronic GVHD, especially biologically targeted treatments, with a special focus on fibrotic changes; and (4) Establish primary endpoints for clinical trials addressing each highly morbid manifestation in relationship to the time point of intervention (early versus late). Alternative endpoints, such as lack of progression and improvement in physical functioning or quality of life, may be suitable for clinical trials in patients with highly morbid manifestations. Finally, new approaches for objective response assessment and exploration of novel trial designs for small populations are required.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.jtct.2021.06.001DOI Listing
June 2021

Functional Selectivity of a Biased Cannabinoid-1 Receptor (CBR) Antagonist.

ACS Pharmacol Transl Sci 2021 Jun 8;4(3):1175-1187. Epub 2021 Apr 8.

Laboratory of Physiologic Studies and Section on Cellular Biophotonics, National Institute on Alcohol Abuse and Alcoholism, Bethesda, Maryland 20892-9304, United States.

Seven-transmembrane receptors signal via G-protein- and β-arrestin-dependent pathways. We describe a peripheral CBR antagonist (MRI-1891) highly biased toward inhibiting CBR-induced β-arrestin-2 (βArr2) recruitment over G-protein activation. In obese wild-type and βArr2-knockout (KO) mice, MRI-1891 treatment reduces food intake and body weight without eliciting anxiety even at a high dose causing partial brain CBR occupancy. By contrast, the unbiased global CBR antagonist rimonabant elicits anxiety in both strains, indicating no βArr2 involvement. Interestingly, obesity-induced muscle insulin resistance is improved by MRI-1891 in wild-type but not in βArr2-KO mice. In C2C12 myoblasts, CBR activation suppresses insulin-induced akt-2 phosphorylation, preventable by MRI-1891, βArr2 knockdown or overexpression of CBR-interacting protein. MRI-1891, but not rimonabant, interacts with nonpolar residues on the N-terminal loop, including F108, and on transmembrane helix-1, including S123, a combination that facilitates βArr2 bias. Thus, CBR promotes muscle insulin resistance via βArr2 signaling, selectively mitigated by a biased CBR antagonist at reduced risk of central nervous system (CNS) side effects.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acsptsci.1c00048DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8204328PMC
June 2021

Spinal astrocyte aldehyde dehydrogenase-2 mediates ethanol metabolism and analgesia in mice.

Br J Anaesth 2021 08 29;127(2):296-309. Epub 2021 Apr 29.

Laboratory for Integrative Neuroscience, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD, USA. Electronic address:

Background: Little is known about the targets in the CNS that mediate ethanol analgesia. This study explores the role of spinal astrocyte aldehyde dehydrogenase-2 (ALDH2), a key ethanol-metabolising enzyme, in the analgesic effects of ethanol in mice.

Methods: Astrocyte and hepatocyte ALHD2-deficient mice were generated and tested in acute and chronic pain models. Cell-type-specific distribution of ALDH2 was analysed by RNA in situ hybridisation in spinal slices from astrocytic ALDH2-deficient mice and their wild-type littermates. Spinal ethanol metabolites and γ-aminobutyric acid (GABA) content were measured using gas chromatography/mass spectrometry and liquid chromatography/mass spectrometry.

Results: ALDH2 mRNA was expressed in both astrocytes and neurones in spinal cord slices. Astrocyte ALDH2-deficient mice had decreased expression of ALDH2 mRNA in astrocytes, but not in neurones. Astrocyte ALDH2 deficiency inhibited ethanol-derived acetate, but not acetaldehyde content in spinal cord tissues. Depletion of spinal astrocyte ALDH2 selectively inhibited ethanol-induced anti-nociceptive effect, but not the effect of ethanol, on motor function. Astrocyte ALDH2 deficiency abolished ethanol-induced GABA elevation. The ethanol metabolite acetate produced anti-nociception and increased GABA synthesis in a manner similar to ethanol. I.T. delivery of either GABA or GABA receptor antagonists prevented ethanol and acetate-induced analgesia.

Conclusions: These findings provide evidence that ALDH2 in spinal astrocytes mediates spinal ethanol metabolism and ethanol-induced analgesic effects by promoting GABA synthesis and GABAergic transmission in spinal cord.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.bja.2021.02.035DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8362281PMC
August 2021

Dual inhibition of CB receptors and iNOS, as a potential novel approach to the pharmacological management of acute and long COVID-19.

Br J Pharmacol 2021 Mar 26. Epub 2021 Mar 26.

Laboratory of Physiologic Studies, National Institute on Alcohol Abuse and Alcoholism (NIAAA), National Institutes of Health (NIH), Bethesda, Maryland, USA.

COVID-19 (SARS-CoV-2) causes multiple inflammatory complications, resulting not only in severe lung inflammation but also harm to other organs. Although the current focus is on the management of acute COVID-19, there is growing concern about long-term effects of COVID-19 (Long Covid), such as fibroproliferative changes in the lung, heart and kidney. Therefore, the identification of therapeutic targets not only for the management of acute COVID-19 but also for preventing Long Covid are needed, and would mitigate against long-lasting health burden and economic costs, in addition to saving lives. COVID-19 induces pathological changes via multiple pathways, which could be targeted simultaneously for optimal effect. We discuss the potential pathologic function of increased activity of the endocannabinoid/CB receptor system and inducible NO synthase (iNOS). We advocate a polypharmacology approach, wherein a single chemical entity simultaneously interacts with CB receptors and iNOS causing inhibition, as a potential therapeutic strategy for COVID-19-related health complications.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/bph.15461DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8251289PMC
March 2021

Brain ethanol metabolism by astrocytic ALDH2 drives the behavioural effects of ethanol intoxication.

Nat Metab 2021 03 22;3(3):337-351. Epub 2021 Mar 22.

Laboratory for Integrative Neuroscience, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD, USA.

Alcohol is among the most widely used psychoactive substances worldwide. Ethanol metabolites such as acetate, thought to be primarily the result of ethanol breakdown by hepatic aldehyde dehydrogenase 2 (ALDH2), contribute to alcohol's behavioural effects and alcoholism. Here, we show that ALDH2 is expressed in astrocytes in the mouse cerebellum and that ethanol metabolism by astrocytic ALDH2 mediates behavioural effects associated with ethanol intoxication. We show that ALDH2 is expressed in astrocytes in specific brain regions and that astrocytic, but not hepatocytic, ALDH2 is required to produce ethanol-derived acetate in the mouse cerebellum. Cerebellar astrocytic ALDH2 mediates low-dose ethanol-induced elevation of GABA levels, enhancement of tonic inhibition and impairment of balance and coordination skills. Thus, astrocytic ALDH2 controls the production, cellular and behavioural effects of alcohol metabolites in a brain-region-specific manner. Our data indicate that astrocytic ALDH2 is an important, but previously under-recognized, target in the brain to alter alcohol pharmacokinetics and potentially treat alcohol use disorder.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s42255-021-00357-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8294184PMC
March 2021

Cholesterol as a modulator of cannabinoid receptor CB signaling.

Sci Rep 2021 Feb 12;11(1):3706. Epub 2021 Feb 12.

National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD, 20852, USA.

Signaling through integral membrane G protein-coupled receptors (GPCRs) is influenced by lipid composition of cell membranes. By using novel high affinity ligands of human cannabinoid receptor CB, we demonstrate that cholesterol increases basal activation levels of the receptor and alters the pharmacological categorization of these ligands. Our results revealed that (2-(6-chloro-2-((2,2,3,3-tetramethylcyclopropane-1-carbonyl)imino)benzo[d]thiazol-3(2H)-yl)ethyl acetate ligand (MRI-2646) acts as a partial agonist of CB in membranes devoid of cholesterol and as a neutral antagonist or a partial inverse agonist in cholesterol-containing membranes. The differential effects of a specific ligand on activation of CB in different types of membranes may have implications for screening of drug candidates in a search of modulators of GPCR activity. MD simulation suggests that cholesterol exerts an allosteric effect on the intracellular regions of the receptor that interact with the G-protein complex thereby altering the recruitment of G protein.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41598-021-83245-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7881127PMC
February 2021

Synthetic cannabinoids induce acute lung inflammation cannabinoid receptor 1 activation.

ERJ Open Res 2020 Jul 17;6(3). Epub 2020 Aug 17.

Laboratory of Physiologic Studies, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Rockville, MD, USA.

https://bit.ly/31bWw4Q.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1183/23120541.00121-2020DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7430153PMC
July 2020

Simultaneous Inhibition of Peripheral CB1R and iNOS Mitigates Obesity-Related Dyslipidemia Through Distinct Mechanisms.

Diabetes 2020 10 17;69(10):2120-2132. Epub 2020 Jul 17.

INSERM Lipids, Nutrition, Cancer (LNC) UMR1231, Team PADYS, University of Burgundy and Franche-Comté, Dijon, France

Diabetic dyslipidemia, characterized by increased plasma triglycerides and decreased HDL cholesterol levels, is a major factor contributing to nonalcoholic steatohepatitis and cardiovascular risk in type 2 diabetes. Activation of the cannabinoid-1 receptor (CB1R) and activation of inducible nitric oxide synthase (iNOS) are associated with nonalcoholic steatohepatitis progression. Here, we tested whether dual-targeting inhibition of hepatic CB1R and iNOS improves diabetic dyslipidemia in mice with diet-induced obesity (DIO mice). DIO mice were treated for 14 days with -MRI-1867, a peripherally restricted hybrid inhibitor of CB1R and iNOS. -MRI-1867, the CB1R-inactive stereoisomer that retains iNOS inhibitory activity, and JD-5037, a peripherally restricted CB1R antagonist, were used to assess the relative contribution of the two targets to the effects of -MRI-1867. -MRI-1867 reduced hepatic steatosis and the rate of hepatic VLDL secretion, upregulated hepatic LDLR expression, and reduced the circulating levels of proprotein convertase subtilisin/kexin type 9 (PCSK9). The decrease in VLDL secretion could be attributed to CB1R blockade, while the reduction of PCSK9 levels and the related increase in LDLR resulted from iNOS inhibition via an mTOR complex 1-dependent mechanism. In conclusion, this approach based on the concomitant inhibition of CB1R and iNOS represents a promising therapeutic strategy for the treatment of dyslipidemia.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.2337/db20-0078DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7506827PMC
October 2020

Endocannabinoid System and Cannabinoid 1 Receptors in Patients With Pharmacoresistant Temporal Lobe Epilepsy and Comorbid Mood Disorders.

Front Behav Neurosci 2020 6;14:52. Epub 2020 May 6.

Department of Pharmacobiology, Center of Research and Advanced Studies, Mexico City, Mexico.

Experimental evidence points out that the activation of the endocannabinoid system induces neuroprotective effects and reduces mood disorders. In the hippocampus of patients with mesial temporal lobe epilepsy (MTLE), studies indicated augmented cannabinoid 1 receptor (CBR) binding, in spite of its low mRNA and protein expressions. Although this situation suggests an enhanced CBR-induced neurotransmission in patients with MTLE, especially those with pharmacoresistant seizures, which present important neuronal damage and high comorbid mood disorders. The present study focused to investigate the status of CBR and the endocannabinoid system by obtaining CBR-induced G-protein signaling efficacy and measuring the tissue levels of endocannabinoids in the hippocampus and the temporal neocortex of patients with pharmacoresistant MTLE. Furthermore, the obtained results were correlated with comorbid anxiety and depression. The experiments revealed that patients with MTLE present increased CBR-induced G-protein signaling efficacy (Emax) as well as an augmented tissue content of anandamide and oleoylethanolamine and low 2-arachidonoylglycerol. Some of these changes were more evident in patients with MTLE without mood disorders. The current findings indicate that pharmacoresistant MTLE is associated with increased CBR-induced transductional mechanisms as well as augmented tissue content of specific endocannabinoids in the hippocampus and the temporal neocortex. The enhanced endocannabinoid neurotransmission may be involved in the absence of comorbid mood disorders in some patients with MTLE.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3389/fnbeh.2020.00052DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7218130PMC
May 2020

Discovery of a NAPE-PLD inhibitor that modulates emotional behavior in mice.

Nat Chem Biol 2020 06 11;16(6):667-675. Epub 2020 May 11.

Roche Innovation Center Basel, F. Hoffman-La Roche Ltd, Basel, Switzerland.

N-acylethanolamines (NAEs), which include the endocannabinoid anandamide, represent an important family of signaling lipids in the brain. The lack of chemical probes that modulate NAE biosynthesis in living systems hamper the understanding of the biological role of these lipids. Using a high-throughput screen, chemical proteomics and targeted lipidomics, we report here the discovery and characterization of LEI-401 as a CNS-active N-acylphosphatidylethanolamine phospholipase D (NAPE-PLD) inhibitor. LEI-401 reduced NAE levels in neuroblastoma cells and in the brain of freely moving mice, but not in NAPE-PLD KO cells and mice, respectively. LEI-401 activated the hypothalamus-pituitary-adrenal axis and impaired fear extinction, thereby emulating the effect of a cannabinoid CB receptor antagonist, which could be reversed by a fatty acid amide hydrolase inhibitor. Our findings highlight the distinctive role of NAPE-PLD in NAE biosynthesis in the brain and suggest the presence of an endogenous NAE tone controlling emotional behavior.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41589-020-0528-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7468568PMC
June 2020

The therapeutic potential of second and third generation CBR antagonists.

Pharmacol Ther 2020 04 9;208:107477. Epub 2020 Jan 9.

Laboratory of Physiologic Studies, National Institute on Alcohol Abuse and Alcoholism (NIAAA), National Institutes of Health (NIH), Bethesda, MD 20892, USA.

Endocannabinoids acting via CB receptors (CBR) play a critical role in regulating energy homeostasis, which was the rationale for the pharmaceutical development of CBR antagonists for the treatment of obesity. Although the first-in-class CBR antagonist rimonabant proved to be effective in mitigating obesity and its multiple cardiometabolic complications, it was withdrawn from clinical use due to CNS-mediated neuropsychiatric side effects, which halted the further therapeutic development of the whole class of these compounds. Compared to the brain, CBRs are expressed at low yet functional levels in peripheral organs involved in regulating energy homeostasis, including liver, skeletal muscle, adipose tissue and endocrine pancreas. In recent preclinical studies, selective targeting of these receptors by 'second generation' peripherally restricted CBR antagonists replicated the metabolic benefits of rimonabant in rodent models of obesity and diabetes without causing CNS-mediated side effects. Increased CBR activity also contributes to complex, multifactorial disorders such as various forms of tissue fibrosis, treatment of which may benefit from simultaneous engagement of more than one therapeutic target. Accordingly, novel 'third generation' hybrid inhibitors of peripheral CBR and inducible NO synthase were tested in mouse models of liver and pulmonary fibrosis where their antifibrotic efficacy was found to exceed the efficacy of drugs that inhibit only one of these targets. In this review, we will discuss the challenges and opportunities offered by second and third generation CBR antagonists and their potential therapeutic uses.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.pharmthera.2020.107477DOI Listing
April 2020

Alcohol Binge-Induced Cardiovascular Dysfunction Involves Endocannabinoid-CB1-R Signaling.

JACC Basic Transl Sci 2019 Sep 23;4(5):625-637. Epub 2019 Sep 23.

Laboratory of Cardiovascular Physiology and Tissue Injury, National Institutes of Health/National Institute on Alcohol Abuse and Alcoholism (NIAAA), Bethesda, Maryland.

Excessive binge alcohol drinking may adversely affect cardiovascular function. In this study we characterize the detailed hemodynamic effects of an acute alcohol binge in mice using multiple approaches and investigate the role of the endocannabinoid-cannabinoid 1 receptor (CB1-R) signaling in these effects. Acute alcohol binge was associated with elevated levels of cardiac endocannabinoid anandamide and profound cardiovascular dysfunction lasting for several hours and redistribution of circulation. These changes were attenuated by CB1-R antagonist or in CB1-R knockout mice. Our results suggest that a single alcohol binge has profound effects on the cardiovascular system, which involve endocannabinoid-CB1-R signaling.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.jacbts.2019.05.007DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6872859PMC
September 2019

Preclinical toxicity evaluation of JD5037, a peripherally restricted CB receptor inverse agonist, in rats and dogs for treatment of nonalcoholic steatohepatitis.

Regul Toxicol Pharmacol 2019 Dec 30;109:104483. Epub 2019 Sep 30.

National Center for Advancing Translational Sciences, National Institute of Health, Bethesda, MD, USA. Electronic address:

JD5037 is a novel peripherally restricted CB receptor (CBR) inverse agonist being developed for the treatment of visceral obesity and its metabolic complications, including nonalcoholic fatty liver disease and dyslipidemia. JD5037 was administered by oral gavage at 10, 40, and 150 mg/kg/day dose levels for up to 34 days to Sprague Dawley rats, and at 5, 20, and 75 mg/kg/day dose levels for 28 consecutive days to Beagle dogs. In rats, higher incidences of stereotypic behaviors were observed in 10 mg/kg females and 40 mg/kg males, and slower responses for reflex and sensory tests were observed only in males at 10 and 40 mg/kg during neurobehavioral testing. Sporadic minimal incidences of decreased activity (males) and seizures (both sexes) were observed in rats during daily clinical observations, without any clear dose-relationship. Male dogs at 75 mg/kg during treatment period, but not recovery period, had an increased incidence of gut associated lymphoid tissue hyperplasia and inflammation in the intestine. In both species, highest dose resulted in lower AUCs indicative of non-linear kinetics. Free access to food increased the plasma AUC by ~4.5-fold at 20 mg/kg in dogs, suggesting presence of food may help in systemic absorption of JD5037 in dogs. Based on the study results, 150 mg/kg/day in rats, and 20 and 75 mg/kg/day doses in male and female dogs, respectively, were determined to be the no-observed-adverse-effect-levels (NOAELs).
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.yrtph.2019.104483DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7017916PMC
December 2019

Glutamate Signaling in Hepatic Stellate Cells Drives Alcoholic Steatosis.

Cell Metab 2019 11 29;30(5):877-889.e7. Epub 2019 Aug 29.

Laboratory of Liver Research, Graduate School of Medical Science and Engineering, KAIST, Daejeon 34141, Republic of Korea. Electronic address:

Activation of hepatocyte cannabinoid receptor-1 (CBR) by hepatic stellate cell (HSC)-derived 2-arachidonoylglycerol (2-AG) drives de novo lipogenesis in alcoholic liver disease (ALD). How alcohol stimulates 2-AG production in HSCs is unknown. Here, we report that chronic alcohol consumption induced hepatic cysteine deficiency and subsequent glutathione depletion by impaired transsulfuration pathway. A compensatory increase in hepatic cystine-glutamate anti-porter xCT boosted extracellular glutamate levels coupled to cystine uptake both in mice and in patients with ALD. Alcohol also induced the selective expression of metabotropic glutamate receptor-5 (mGluR5) in HSCs where mGluR5 activation stimulated 2-AG production. Consistently, genetic or pharmacologic inhibition of mGluR5 or xCT attenuated alcoholic steatosis in mice via the suppression of 2-AG production and subsequent CBR-mediated de novo lipogenesis. We conclude that a bidirectional signaling operates at a metabolic synapse between hepatocytes and HSCs through xCT-mediated glutamate-mGluR5 signaling to produce 2-AG, which induces CBR-mediated alcoholic steatosis.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.cmet.2019.08.001DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6834910PMC
November 2019

Interplay of Liver-Heart Inflammatory Axis and Cannabinoid 2 Receptor Signaling in an Experimental Model of Hepatic Cardiomyopathy.

Hepatology 2020 04 24;71(4):1391-1407. Epub 2020 Jan 24.

Laboratory of Cardiovascular Physiology and Tissue Injury, National Institutes of Health, National Institute on Alcohol Abuse and Alcoholism, Bethesda, MD.

Background And Aims: Hepatic cardiomyopathy, a special type of heart failure, develops in up to 50% of patients with cirrhosis and is a major determinant of survival. However, there is no reliable model of hepatic cardiomyopathy in mice. We aimed to characterize the detailed hemodynamics of mice with bile duct ligation (BDL)-induced liver fibrosis, by monitoring echocardiography and intracardiac pressure-volume relationships and myocardial structural alterations. Treatment of mice with a selective cannabinoid-2 receptor (CB -R) agonist, known to attenuate inflammation and fibrosis, was used to explore the impact of liver inflammation and fibrosis on cardiac function.

Approach And Results: BDL induced massive inflammation (increased leukocyte infiltration, inflammatory cytokines, and chemokines), oxidative stress, microvascular dysfunction, and fibrosis in the liver. These pathological changes were accompanied by impaired diastolic, systolic, and macrovascular functions; cardiac inflammation (increased macrophage inflammatory protein 1, interleukin-1, P-selectin, cluster of differentiation 45-positive cells); and oxidative stress (increased malondialdehyde, 3-nitrotyrosine, and nicotinamide adenine dinucleotide phosphate oxidases). CB -R up-regulation was observed in both livers and hearts of mice exposed to BDL. CB -R activation markedly improved hepatic inflammation, impaired microcirculation, and fibrosis. CB -R activation also decreased serum tumor necrosis factor-alpha levels and improved cardiac dysfunction, myocardial inflammation, and oxidative stress, underlining the importance of inflammatory mediators in the pathology of hepatic cardiomyopathy.

Conclusions: We propose BDL-induced cardiomyopathy in mice as a model for hepatic/cirrhotic cardiomyopathy. This cardiomyopathy, similar to cirrhotic cardiomyopathy in humans, is characterized by systemic hypotension and impaired macrovascular and microvascular function accompanied by both systolic and diastolic dysfunction. Our results indicate that the liver-heart inflammatory axis has a pivotal pathophysiological role in the development of hepatic cardiomyopathy. Thus, controlling liver and/or myocardial inflammation (e.g., with selective CB -R agonists) may delay or prevent the development of cardiomyopathy in severe liver disease.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/hep.30916DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7048661PMC
April 2020

Dual inhibition of cannabinoid CB receptor and inducible NOS attenuates obesity-induced chronic kidney disease.

Br J Pharmacol 2020 01 27;177(1):110-127. Epub 2019 Dec 27.

Obesity and Metabolism Laboratory, Institute for Drug Research, School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel.

Background And Purpose: Obesity, an important risk factor for developing chronic kidney disease (CKD), affects the kidneys by two main molecular signalling pathways: the endocannabinoid/CB receptor system, whose activation in obesity promotes renal inflammation, fibrosis, and injury, and the inducible NOS (iNOS), which generates ROS resulting in oxidative stress. Hence, a compound that inhibits both peripheral CB receptors and iNOS may serve as an effective therapeutic agent against obesity-induced CKD.

Experimental Approach: Here, we describe the effect of a novel peripherally restricted, orally bioavailable dual CB receptor/iNOS antagonist, MRI-1867 (3 mg·kg ), in ameliorating obesity-induced CKD, and compared its metabolic and renal efficacies to a stand-alone peripheral CB receptor antagonist (JD5037; 3 mg·kg ), iNOS antagonist (1400W; 10 mg·kg ), and pair feeding. Mice with high-fat diet-induced obesity were treated orally with these compounds or vehicle (Veh) for 28 days. Standard diet-fed mice treated with Veh served as controls.

Key Results: Enhanced expression of CB receptors and iNOS in renal tubules was found in human kidney patients with obesity and other CKDs. The hybrid inhibitor ameliorated obesity-induced kidney morphological and functional changes via decreasing kidney inflammation, fibrosis, oxidative stress, and renal injury. Some of these features were independent of the improved metabolic profile mediated via inhibition of CB receptors. An additional interesting finding is that these beneficial effects on the kidney were partially associated with modulating renal adiponectin signalling.

Conclusions And Implications: Collectively, our results highlight the therapeutic relevance of blocking CB receptors and iNOS in ameliorating obesity-induced CKD.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/bph.14849DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6976880PMC
January 2020

Bleomycin Induces Drug Efflux in Lungs. A Pitfall for Pharmacological Studies of Pulmonary Fibrosis.

Am J Respir Cell Mol Biol 2020 02;62(2):178-190

Laboratory of Physiologic Studies, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Rockville, Maryland; and.

ATP-binding cassette (ABC) transporters are evolutionarily conserved membrane proteins that pump a variety of endogenous substrates across cell membranes. Certain subfamilies are known to interact with pharmaceutical compounds, potentially influencing drug delivery and treatment efficacy. However, the role of drug resistance-associated ABC transporters has not been examined in idiopathic pulmonary fibrosis (IPF) or its animal model: the bleomycin (BLM)-induced murine model. Here, we investigate the expression of two ABC transporters, P-gp (permeability glycoprotein) and BCRP (breast cancer resistance protein), in human IPF lung tissue and two different BLM-induced mouse models of pulmonary fibrosis. We obtained human IPF specimens from patients during lung transplantation and administered BLM to male C57BL/6J mice either by oropharyngeal aspiration (1 U/kg) or subcutaneous osmotic infusion (100 U/kg over 7 d). We report that P-gp and BCRP expression in lungs of patients with IPF was comparable to controls. However, murine lungs expressed increased levels of P-gp and BCRP after oropharyngeal and subcutaneous BLM administration. We localized this upregulation to multiple pulmonary cell types, including alveolar fibroblasts, endothelial cells, and type 2 epithelial cells. Functionally, this effect reduced murine lung exposure to nintedanib, a U.S. Food and Drug Administration-approved IPF therapy known to be a P-gp substrate. The study reveals a discrepancy between IPF pathophysiology and the common animal model of lung fibrosis. BLM-induced drug efflux in the murine lungs may present an uncontrolled confounding variable in the preclinical study of IPF drug candidates, and these findings will facilitate disease model validation and enhance new drug discoveries that will ultimately improve patient outcomes.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1165/rcmb.2018-0147OCDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6993545PMC
February 2020

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

Cell Metab 2019 06 16;29(6):1320-1333.e8. Epub 2019 May 16.

Laboratory of Physiologic Studies, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD 20892, USA. Electronic address:

Endocannabinoids acting on the cannabinoid-1 receptor (CBR) or ghrelin acting on its receptor (GHS-R) both promote alcohol-seeking behavior, but an interaction between the two signaling systems has not been explored. Here, we report that the peripheral CBR inverse agonist JD5037 reduces ethanol drinking in wild-type mice but not in mice lacking CBR, ghrelin peptide or GHS-R. 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 CBR or GHS-R blockade to reduce ethanol drinking. We conclude that blocking CBR in ghrelin-producing cells reduces alcohol drinking by inhibiting the formation of active ghrelin and its signaling via gastric vagal afferents. Thus, peripheral CBR blockade may have therapeutic potential in the treatment of alcoholism.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.cmet.2019.04.012DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6551287PMC
June 2019

Crystal Structure of the Human Cannabinoid Receptor CB2.

Cell 2019 01 10;176(3):459-467.e13. Epub 2019 Jan 10.

iHuman Institute, ShanghaiTech University, Shanghai 201210, China; School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China. Electronic address:

The cannabinoid receptor CB2 is predominately expressed in the immune system, and selective modulation of CB2 without the psychoactivity of CB1 has therapeutic potential in inflammatory, fibrotic, and neurodegenerative diseases. Here, we report the crystal structure of human CB2 in complex with a rationally designed antagonist, AM10257, at 2.8 Å resolution. The CB2-AM10257 structure reveals a distinctly different binding pose compared with CB1. However, the extracellular portion of the antagonist-bound CB2 shares a high degree of conformational similarity with the agonist-bound CB1, which led to the discovery of AM10257's unexpected opposing functional profile of CB2 antagonism versus CB1 agonism. Further structural analysis using mutagenesis studies and molecular docking revealed the molecular basis of their function and selectivity for CB2 and CB1. Additional analyses of our designed antagonist and agonist pairs provide important insight into the activation mechanism of CB2. The present findings should facilitate rational drug design toward precise modulation of the endocannabinoid system.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.cell.2018.12.011DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6713262PMC
January 2019

Characterization of heterogeneous redox responses in hepatocellular carcinoma patients using network analysis.

EBioMedicine 2019 Feb 31;40:471-487. Epub 2018 Dec 31.

Science for Life Laboratory, KTH - Royal Institute of Technology, SE-171 21 Stockholm, Sweden; Department of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden; Centre for Host-Microbiome Interactions, Dental Institute, King's College London, London, UK. Electronic address:

Background: Redox metabolism is often considered a potential target for cancer treatment, but a systematic examination of redox responses in hepatocellular carcinoma (HCC) is missing.

Methods: Here, we employed systems biology and biological network analyses to reveal key roles of genes associated with redox metabolism in HCC by integrating multi-omics data.

Findings: We found that several redox genes, including 25 novel potential prognostic genes, are significantly co-expressed with liver-specific genes and genes associated with immunity and inflammation. Based on an integrative analysis, we found that HCC tumors display antagonistic behaviors in redox responses. The two HCC groups are associated with altered fatty acid, amino acid, drug and hormone metabolism, differentiation, proliferation, and NADPH-independent vs -dependent antioxidant defenses. Redox behavior varies with known tumor subtypes and progression, affecting patient survival. These antagonistic responses are also displayed at the protein and metabolite level and were validated in several independent cohorts. We finally showed the differential redox behavior using mice transcriptomics in HCC and noncancerous tissues and associated with hypoxic features of the two redox gene groups.

Interpretation: Our integrative approaches highlighted mechanistic differences among tumors and allowed the identification of a survival signature and several potential therapeutic targets for the treatment of HCC.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.ebiom.2018.12.057DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6412169PMC
February 2019

Cannabinoid-1 Receptor Antagonism Improves Glycemic Control and Increases Energy Expenditure Through Sirtuin-1/Mechanistic Target of Rapamycin Complex 2 and 5'Adenosine Monophosphate-Activated Protein Kinase Signaling.

Hepatology 2019 04 6;69(4):1535-1548. Epub 2019 Mar 6.

Laboratory of Physiologic Studies, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD.

Endocannabinoids promote energy conservation in obesity, whereas cannabinoid-1 receptor (CB R) blockade reverses body weight gain and insulin resistance and increases energy expenditure. Here we investigated the molecular mechanisms of the catabolic effects of CB R blockade in the liver. Exposure of primary mouse hepatocytes and HepG2 cells to the CB R agonist arachidonyl-2'-chloroethylamide inhibited the expression of Sirtuin-1 (Sirt1) and Rictor, a component of mechanistic target of rapamycin complex 2 (mTORC2) and suppressed insulin-induced Akt phosphorylation at serine 473. These effects were reversed by peripheral CB R antagonist JD5037 in control hepatocytes but not in hepatocytes deficient in Sirt1 and/or Rictor, indicating that these two proteins are required for the CB R-mediated inhibition of insulin signaling. Feeding C57BL/6J mice a high-fat diet (HFD) inhibited hepatic Sirt1/mTORC2/Akt signaling, and the inhibition was reversed by rimonabant or JD5037 in wild-type but not liver-specific Sirt1 (Sirt1-LKO) mice, to levels observed in hepatocyte-specific CB R mice. A similar attenuation of hyperglycemia and hyperinsulinemia in wild-type mice with obesity but not in Sirt1-LKO mice could be attributed to insufficient reversal of HFD-induced mitochondrial reactive oxygen species generation in peripheral tissues in the latter. In contrast, JD5037 treatment was equally effective in HFD-fed wild-type and Sirt1-LKO mice in reducing hepatic steatosis, increasing fatty acid β-oxidation, and activating 5'adenosine monophosphate-activated protein kinase (AMPK) through liver kinase B1 (LKB1), resulting in a similar increase in total energy expenditure in the two strains. Conclusion: Peripheral CB R blockade in mice with obesity improves glycemic control through the hepatic Sirt1/mTORC2/Akt pathway, whereas it increases fatty acid oxidation through LKB1/AMPK signaling.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/hep.30364DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6438767PMC
April 2019

Synthesis of C -labeled, dual-target inhibitor of cannabinoid-1 receptor (CB R) and inducible nitric oxide synthase (iNOS).

J Labelled Comp Radiopharm 2018 May 23. Epub 2018 May 23.

Laboratory of Physiologic Studies and National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Rockville, Maryland, USA.

Cannabinoid-1 receptor (CB R) antagonists/inverse agonists have great potential in the treatment of metabolic disorders like dyslipidemia, type 2 diabetes, and nonalcoholic steatohepatitis. Cannabinoid-1 receptor inverse agonists have also been reported to be effective in mitigating fibrotic disorders in murine models. Inducible nitric oxide synthase is another promising target implicated in fibrotic and inflammatory disorders. We have disclosed MRI-1867 as a potent and selective, peripherally acting dual-target inhibitor of the CB R and inducible nitric oxide synthase (iNOS). Herein, we report the synthesis of [ C ]-MRI-1867 as a racemate from commercially available chlorobenzene- C as the starting, stable-isotope label reagent. The racemic [ C ]-MRI-1867 was further processed to the stable-isotope-labeled enantiopure compounds using chiral chromatography. Both racemic [ C ]-MRI-1867 and S- C -MRI-1867 will be used to quantitate unlabeled S-MRI-1867 during clinical drug metabolism and pharmacokinetics studies and will be used as a liquid chromatography-tandem mass spectrometry bioanalytical standard.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/jlcr.3639DOI Listing
May 2018

Disruption of Renal Arginine Metabolism Promotes Kidney Injury in Hepatorenal Syndrome in Mice.

Hepatology 2018 10;68(4):1519-1533

Laboratory of Cardiovascular Physiology and Tissue Injury, National Institutes of Health/NIAAA, Bethesda, MD.

Tubular dysfunction is an important feature of renal injury in hepatorenal syndrome (HRS) in patients with end-stage liver disease. The pathogenesis of kidney injury in HRS is elusive, and there are no clinically relevant rodent models of HRS. We investigated the renal consequences of bile duct ligation (BDL)-induced hepatic and renal injury in mice in vivo by using biochemical assays, real-time polymerase chain reaction (PCR), Western blot, mass spectrometry, histology, and electron microscopy. BDL resulted in time-dependent hepatic injury and hyperammonemia which were paralleled by tubular dilation and tubulointerstitial nephritis with marked upregulation of lipocalin-2, kidney injury molecule 1 (KIM-1) and osteopontin. Renal injury was associated with dramatically impaired microvascular flow and decreased endothelial nitric oxide synthase (eNOS) activity. Gene expression analyses signified proximal tubular epithelial injury, tissue hypoxia, inflammation, and activation of the fibrotic gene program. Marked changes in renal arginine metabolism (upregulation of arginase-2 and downregulation of argininosuccinate synthase 1), resulted in decreased circulating arginine levels. Arginase-2 knockout mice were partially protected from BDL-induced renal injury and had less impairment in microvascular function. In human-cultured proximal tubular epithelial cells hyperammonemia per se induced upregulation of arginase-2 and markers of tubular cell injury.

Conclusion: We propose that hyperammonemia may contribute to impaired renal arginine metabolism, leading to decreased eNOS activity, impaired microcirculation, tubular cell death, tubulointerstitial nephritis and fibrosis. Genetic deletion of arginase-2 partially restores microcirculation and thereby alleviates tubular injury. We also demonstrate that BDL in mice is an excellent, clinically relevant model to study the renal consequences of HRS. (Hepatology 2018; 00:000-000).
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/hep.29915DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6173643PMC
October 2018

Feasibility Evaluation of Myocardial Cannabinoid Type 1 Receptor Imaging in Obesity: A Translational Approach.

JACC Cardiovasc Imaging 2018 02;11(2 Pt 2):320-332

Department of Radiology, Division of Nuclear Medicine, Nuclear Cardiovascular Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland. Electronic address:

Objectives: The aim of this study was to evaluate the feasibility of targeted imaging of myocardial cannabinoid type 1 receptor (CB1-R) and its potential up-regulation in obese mice with translation to humans using [C]-OMAR and positron emission tomography (PET)/computed tomography (CT).

Background: Activation of myocardial CB1-R by endocannabinoids has been implicated in cardiac dysfunction in diabetic mice. Obesity may lead to an up-regulation of myocardial CB1-R, potentially providing a mechanistic link between obesity and the initiation and/or progression of cardiomyopathy.

Methods: Binding specificity of [C]-OMAR to CB1-R was investigated by blocking studies with rimonabant in mice. The heart was harvested from each mouse, and its radioactivity was determined by γ-counter. Furthermore, [C]-OMAR dynamic micro-PET/CT was carried out in obese and normal-weight mice. Ex vivo validation was performed by droplet digital polymerase chain reaction (absolute quantification) and RNAscope Technology (an in situ ribonucleic acid analysis platform). Subsequently, myocardial CB1-R expression was probed noninvasively with intravenous injection of CB1-R ligand [C]-OMAR and PET/CT in humans with advanced obesity and normal-weight human control subjects, respectively.

Results: Rimonabant significantly blocked OMAR uptake in the heart muscle compared with vehicle, signifying specific binding of OMAR to the CB1-R in the myocardium. The myocardial OMAR retention quantified by micro-PET/CT in mice was significantly higher in obese compared with normal-weight mice. Absolute quantification of CB1-R gene expression with droplet digital polymerase chain reaction and in situ hybridization confirmed CB1-R up-regulation in all major myocardial cell types (e.g., cardiomyocytes, endothelium, vascular smooth muscle cells, and fibroblasts) of obese mice. Obese mice also had elevated myocardial levels of endocannabinoids anandamide and 2-arachidonoylglycerol compared with lean mice. Translation to humans revealed higher myocardial OMAR retention in advanced obesity compared with normal-weight subjects.

Conclusions: Noninvasive imaging of cardiac CB1-R expression in obesity is feasible applying [C]-OMAR and PET/CT. These results may provide a rationale for further clinical testing of CB1-R-targeted molecular imaging in cardiometabolic diseases.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.jcmg.2017.11.019DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6178217PMC
February 2018

Decreasing CB receptor signaling in Kupffer cells improves insulin sensitivity in obese mice.

Mol Metab 2017 11 1;6(11):1517-1528. Epub 2017 Sep 1.

Laboratory of Physiologic Studies, National Institute on Alcohol Abuse and Alcoholism (NIAAA), National Institutes of Health (NIH), Bethesda, MD 20852, USA. Electronic address:

Objective: Obesity-induced accumulation of ectopic fat in the liver is thought to contribute to the development of insulin resistance, and increased activity of hepatic CBR has been shown to promote both processes. However, lipid accumulation in liver can be experimentally dissociated from insulin resistance under certain conditions, suggesting the involvement of additional mechanisms. Obesity is also associated with pro-inflammatory changes which, in turn, can promote insulin resistance. Kupffer cells (KCs), the liver's resident macrophages, are the major source of pro-inflammatory cytokines in the liver, such as TNF-α, which has been shown to inhibit insulin signaling in multiple cell types, including hepatocytes. Here, we sought to identify the role of CBR in KCs in obesity-induced hepatic insulin resistance.

Methods: We used intravenously administered β-D-glucan-encapsulated siRNA to knock-down CBR gene expression selectively in KCs.

Results: We demonstrate that a robust knock-down of the expression of Cnr1, the gene encoding CBR, results in improved glucose tolerance and insulin sensitivity in diet-induced obese mice, without affecting hepatic lipid content or body weight. Moreover, Cnr1 knock-down in KCs was associated with a shift from pro-inflammatory M1 to anti-inflammatory M2 cytokine profile and improved insulin signaling as reflected by increased insulin-induced Akt phosphorylation.

Conclusion: These findings suggest that CBR expressed in KCs plays a critical role in obesity-related hepatic insulin resistance via a pro-inflammatory mechanism.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.molmet.2017.08.011DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5681272PMC
November 2017

Cannabinoid-1 receptor deletion in podocytes mitigates both glomerular and tubular dysfunction in a mouse model of diabetic nephropathy.

Diabetes Obes Metab 2018 03 3;20(3):698-708. Epub 2017 Dec 3.

Laboratory of Physiologic Studies, National Institute on Alcohol Abuse and Alcoholism (NIAAA), National Institutes of Health (NIH), Bethesda, Maryland.

Aims: To determine the specific role of podocyte-expressed cannabinoid-1 receptor (CB R) in the development of diabetic nephropathy (DN), relative to CB R in other renal cell types.

Material And Methods: We developed a mouse model with a podocyte-specific deletion of CB R (pCB1Rko) and challenged this model with streptozotocin (STZ)-induced type-1 DN. We also assessed the podocyte response to high glucose in vitro and its effects on CB R activation.

Results: High glucose exposure for 48 hours led to an increase in CB R gene expression (CNR1) and endocannabinoid production in cultured human podocytes. This was associated with podocyte injury, reflected by decreased podocin and nephrin expression. These changes could be prevented by Cnr1-silencing, thus identifying CB1R as a key player in podocyte injury. After 12 weeks of chronic hyperglycaemia, STZ-treated pCB1Rko mice showed elevated blood glucose similar to that of their wild-type littermates. However, they displayed less albuminuria and less podocyte loss than STZ-treated wild-type mice. Unexpectedly, pCB1Rko mice also have milder tubular dysfunction, fibrosis and reduction of cortical microcirculation compared to wild-type controls, which is mediated, in part, by podocyte-derived endocannabinoids acting via CB R on proximal tubular cells.

Conclusions: Activation of CB R in podocytes contributes to both glomerular and tubular dysfunction in type-1 DN, which highlights the therapeutic potential of peripheral CB R blockade.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/dom.13150DOI Listing
March 2018

Peripheral cannabinoid-1 receptor blockade restores hypothalamic leptin signaling.

Mol Metab 2017 10 24;6(10):1113-1125. Epub 2017 Jun 24.

Laboratory of Physiologic Studies, National Institute on Alcohol Abuse and Alcoholism, USA. Electronic address:

Objective: In visceral obesity, an overactive endocannabinoid/CB receptor (CBR) system promotes increased caloric intake and decreases energy expenditure, which are mitigated by global or peripheral CBR blockade. In mice with diet-induced obesity (DIO), inhibition of food intake by the peripherally restricted CBR antagonist JD5037 could be attributed to endogenous leptin due to the rapid reversal of hyperleptinemia that maintains leptin resistance, but the signaling pathway engaged by leptin has remained to be determined.

Methods: We analyzed the hypothalamic circuitry targeted by leptin following chronic treatment of DIO mice with JD5037.

Results: Leptin treatment or an increase in endogenous leptin following fasting/refeeding induced STAT3 phosphorylation in neurons in the arcuate nucleus (ARC) in lean and JD5037-treated DIO mice, but not in vehicle-treated DIO animals. Co-localization of pSTAT3 in leptin-treated mice was significantly less common with NPY than with POMC ARC neurons. The hypophagic effect of JD5037 was absent in melanocortin-4 receptor (MC4R) deficient obese mice or DIO mice treated with a MC4R antagonist, but was maintained in NPY mice kept on a high-fat diet.

Conclusions: Peripheral CBR blockade in DIO restores sensitivity to endogenous leptin, which elicits hypophagia via the re-activation of melanocortin signaling in the ARC.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.molmet.2017.06.010DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5641628PMC
October 2017

Proximal Tubular Cannabinoid-1 Receptor Regulates Obesity-Induced CKD.

J Am Soc Nephrol 2017 Dec 31;28(12):3518-3532. Epub 2017 Aug 31.

Obesity and Metabolism Laboratory, Institute for Drug Research, School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel;

Obesity-related structural and functional changes in the kidney develop early in the course of obesity and occur independently of hypertension, diabetes, and dyslipidemia. Activating the renal cannabinoid-1 receptor (CBR) induces nephropathy, whereas CBR blockade improves kidney function. Whether these effects are mediated a specific cell type within the kidney remains unknown. Here, we show that specific deletion of CBR in the renal proximal tubule cells did not protect the mice from obesity, but markedly attenuated the obesity-induced lipid accumulation in the kidney and renal dysfunction, injury, inflammation, and fibrosis. These effects associated with increased activation of liver kinase B1 and the energy sensor AMP-activated protein kinase, as well as enhanced fatty acid -oxidation. Collectively, these findings indicate that renal proximal tubule cell CBR contributes to the pathogenesis of obesity-induced renal lipotoxicity and nephropathy by regulating the liver kinase B1/AMP-activated protein kinase signaling pathway.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1681/ASN.2016101085DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5698062PMC
December 2017
-->