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PhD à l'Institut Max-Planck de Munich (1997-2001)
Post-Doc, Institut Max-Planck, Munich (2001-2004)
CR1 Neurocentre Magendie, Bordeaux (2007)

156 publication(s) since Mai 1996:

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The indicated IF have been collected by the Web of Sciences in

2009 | Curr Top Behav Neurosci   IF 2.7
Roles of the endocannabinoid system in learning and memory.
Marsicano G, Lafenetre P

The endocannabinoid system (ECS) plays a central role in the regulation of learning and memory processes. The fine-tuned regulation of neural transmission by the system is likely to be the mechanism underlying this important function. In this chapter, we review the data in the literature showing the direct involvement of the physiological activation of cannabinoid receptors in the modulation of different forms of learning and memory. When possible, we also address the likely mechanisms of this involvement. Finally, given the apparent special role of the ECS in the extinction of fear, we propose a reasonable model to assess how neuronal networks could be influenced by the endocannabinoids in these processes. Overall, the data reviewed indicate that, despite the enormous progress of recent years, much is still to be done to fully elucidate the mechanisms of the ECS influence on learning and memory processes.

09/2008 | J Clin Invest   IF 12.3
Hepatic CB1 receptor is required for development of diet-induced steatosis, dyslipidemia, and insulin and leptin resistance in mice
Osei-Hyiaman D, Liu J, Zhou L, Godlewski G, Harvey-White J, Jeong W I, Batkai S, Marsicano G, Lutz B, Buettner C, Kunos G

Diet-induced obesity is associated with fatty liver, insulin resistance, leptin resistance, and changes in plasma lipid profile. Endocannabinoids have been implicated in the development of these associated phenotypes, because mice deficient for the cannabinoid receptor CB1 (CB1-/-) do not display these changes in association with diet-induced obesity. The target tissues that mediate these effects, however, remain unknown. We therefore investigated the relative role of hepatic versus extrahepatic CB1 receptors in the metabolic consequences of a high-fat diet, using liver-specific CB1 knockout (LCB1-/-) mice. LCB1(-/-) mice fed a high-fat diet developed a similar degree of obesity as that of wild-type mice, but, similar to CB1(-/-) mice, had less steatosis, hyperglycemia, dyslipidemia, and insulin and leptin resistance than did wild-type mice fed a high-fat diet. CB1 agonist-induced increase in de novo hepatic lipogenesis and decrease in the activity of carnitine palmitoyltransferase-1 and total energy expenditure were absent in both CB1(-/-) and LCB1(-/-) mice. We conclude that endocannabinoid activation of hepatic CB1 receptors contributes to the diet-induced steatosis and associated hormonal and metabolic changes, but not to the increase in adiposity, observed with high-fat diet feeding. Theses studies suggest that peripheral CB1 receptors could be selectively targeted for the treatment of fatty liver, impaired glucose homeostasis, and dyslipidemia in order to minimize the neuropsychiatric side effects of nonselective CB1 blockade during treatment of obesity-associated conditions.

The complete genetic loss or pharmacological blockade of cannabinoid receptor type 1 (CB1) in mice results in both altered behavioral performance and increased stress hormone secretion in response to stressful encounters such as forced swim test (FST) exposure. CB1 is expressed on nerve terminals belonging to different neurotransmitter systems, including the glutamatergic and GABAergic system, where it is able to suppress excitatory and inhibitory neurotransmission, respectively. In the current study, we used the conditional mutagenesis approach in mice to investigate the neurotransmitter systems involved in these behavioral and neuroendocrine phenotypes in regard to CB1 signaling. Mice lacking CB1 in cortical glutamatergic neurons (Glu-CB1(-/-)) showed decreased passive stress coping (decreased immobility) in the FST, whereas mice lacking CB1 in principal forebrain neurons (CaMK-CB1(-/-)) and GABAergic neurons (GABA-CB1(-/-)), respectively, behaved as littermate controls. However, we found increased FST-induced corticosterone secretion only in CaMK-CB1(-/-) mice, whereas Glu-CB1(-/-) and GABA-CB1(-/-) mice exhibited normal corticosterone release as compared to controls. Thus, behavioral and neuroendocrine acute stress coping in response to the FST is mainly influenced by CB1 signaling on different glutamatergic neuronal subpopulations, but not by CB1 on GABAergic neurons.

08/2008 | Diabetes   IF 7.2
Cannabinoid type 1 receptor blockade promotes mitochondrial biogenesis through endothelial nitric oxide synthase expression in white adipocytes
Tedesco L, Valerio A, Cervino C, Cardile A, Pagano C, Vettor R, Pasquali R, Carruba M O, Marsicano G, Lutz B, Pagotto U, Nisoli E

OBJECTIVE: Cannabinoid type 1 (CB1) receptor blockade decreases body weight and adiposity in obese subjects; however, the underlying mechanism is not yet fully understood. Nitric oxide (NO) produced by endothelial NO synthase (eNOS) induces mitochondrial biogenesis and function in adipocytes. This study was undertaken to test whether CB1 receptor blockade increases the espression of eNOS and mitochondrial biogenesis in white adipocytes. RESEARCH DESIGN AND METHODS: We examined the effects on eNOS and mitochondrial biogenesis of selective pharmacological blockade of CB1 receptors by SR141716 (rimonabant) in mouse primary white adipocytes. We also examined eNOS expression and mitochondrial biogenesis in white adipose tissue (WAT) and isolated mature white adipocytes of CB1 receptor-deficient (CB1(-/-)) and chronically SR141716-treated mice on either a standard or high-fat diet. RESULTS: SR141716 treatment increased eNOS expression in cultured white adipocytes. Moreover, SR141716 increased mitochondrial DNA amount, mRNA levels of genes involved in mitochondrial biogenesis, and mitochondrial mass and function through eNOS induction, as demonstrated by reversal of SR141716 effects by small interfering RNA-mediated decrease in eNOS. While high-fat diet-fed wild-type mice showed reduced eNOS expression and mitochondrial biogenesis in WAT and isolated mature white adipocytes, genetic CB1 receptor deletion or chronic treatment with SR141716 restored these parameters to the levels observed in wild-type mice on the standard diet, an effect linked to the prevention of adiposity and body weight increase. CONCLUSIONS: CB1 receptor blockade increases mitochondrial biogenesis in white adipocytes by inducing the expression of eNOS. This is linked to the prevention of high-fat diet-induced fat accumulation, without concomitant changes in food intake.

07/2008 | Ann Neurol   IF 9.5
Cannabinoids enhance susceptibility of immature brain to ethanol neurotoxicity
Hansen H H, Krutz B, Sifringer M, Stefovska V, Bittigau P, Pragst F, Marsicano G, Lutz B, Ikonomidou C

OBJECTIVE: Marijuana and alcohol are most widely abused drugs among women of reproductive age. Neurocognitive deficits have been reported in children whose mothers used marijuana during pregnancy. Maternal consumption of ethanol is known to cause serious developmental deficits METHODS: Infant rats and mice received systemic injections of Delta(9)-tetrahydrocannabinol (THC; 1-10mg/kg) or the synthetic cannabinoid WIN 55,212-2 (1-10mg/kg), alone or in combination with subtoxic and toxic ethanol doses, and apoptotic neurodegeneration was studied in the brains RESULTS: Acute administration of THC (1-10mg/kg), the principal psychoactive cannabinoid of marijuana, markedly enhanced proapoptotic properties of ethanol in the neonatal rat brain. THC did not induce neurodegeneration when administered alone. Neuronal degeneration became disseminated and severe when THC was combined with a mildly intoxicating ethanol dose (3gm/kg), with the effect of this drug combination resembling the massive apoptotic death observed when administering ethanol alone at much higher doses. The detrimental effect of THC was mimicked by the synthetic cannabinoid WIN 55,212-2 (1-10mg/kg) and counteracted by the CB(1) receptor antagonist SR141716A (0.4mg/kg). THC enhanced the proapoptotic effect of the GABA(A) agonist phenobarbital and the N-methyl-D-aspartate receptor antagonist dizocilpine. Interestingly, infant CB(1) receptor knock-out mice were less susceptible to the neurotoxic effect of ethanol. Furthermore, the CB(1) receptor antagonist SR141716A ameliorated neurotoxicity of ethanol INTERPRETATION: These observations indicate that CB(1) receptor activation modulates GABAergic and glutamatergic neurotransmission and primes the developing brain to suffer apoptotic neuronal death.

24/06/2008 | Proc Natl Acad Sci U S A   IF 9.6
Endocannabinoid signaling controls pyramidal cell specification and long-range axon patterning
Mulder J, Aguado T, Keimpema E, Barabas K, Ballester Rosado C J, Nguyen L, Monory K, Marsicano G, Di Marzo V, Hurd Y L, Guillemot F, Mackie K, Lutz B, Guzman M, Lu H C, Galve-Roperh I, Harkany T

Endocannabinoids (eCBs) have recently been identified as axon guidance cues shaping the connectivity of local GABAergic interneurons in the developing cerebrum. However, eCB functions during pyramidal cell specification and establishment of long-range axonal connections are unknown. Here, we show that eCB signaling is operational in subcortical proliferative zones from embryonic day 12 in the mouse telencephalon and controls the proliferation of pyramidal cell progenitors and radial migration of immature pyramidal cells. When layer patterning is accomplished, developing pyramidal cells rely on eCB signaling to initiate the elongation and fasciculation of their long-range axons. Accordingly, CB(1) cannabinoid receptor (CB(1)R) null and pyramidal cell-specific conditional mutant (CB(1)R(f/f,NEX-Cre)) mice develop deficits in neuronal progenitor proliferation and axon fasciculation. Likewise, axonal pathfinding becomes impaired after in utero pharmacological blockade of CB(1)Rs. Overall, eCBs are fundamental developmental cues controlling pyramidal cell development during corticogenesis.

06/2008 | Pharmacogenomics J   IF 3.5
Impaired cannabinoid receptor type 1 signaling interferes with stress-coping behavior in mice
Steiner M A, Wanisch K, Monory K, Marsicano G, Borroni E, Bachli H, Holsboer F, Lutz B, Wotjak C T

Dysregulation of the endocannabinoid system is known to interfere with emotional processing of stressful events. Here, we studied the role of cannabinoid receptor type 1 (CB1) signaling in stress-coping behaviors using the forced swim test (FST) with repeated exposures. We compared effects of genetic inactivation with pharmacological blockade of CB1 receptors both in male and female mice. In addition, we investigated potential interactions of the endocannabinoid system with monoaminergic and neurotrophin systems of the brain. Naive CB1 receptor-deficient mice (CB1-/-) showed increased passive stress-coping behaviors as compared to wild-type littermates (CB1+/+) in the FST, independent of sex. These findings were partially reproduced in C57BL/6N animals and fully reproduced in female CB1+/+ mice by pharmacological blockade of CB1 receptors with the CB1 receptor antagonist SR141716. The specificity of SR141716 was confirmed in female CB1-/- mice, where it failed to affect behavioral performance. Sensitivity to the antidepressants desipramine and paroxetine was preserved, but slightly altered in female CB1-/- mice. There were no genotype differences between CB1+/+ and CB1-/- mice in monoamine oxidase A and B activities under basal conditions, nor in monoamine content of hippocampal tissue after FST exposure. mRNA expression of vesicular glutamate transporter type 1 was unaffected in CB1-/- mice, but mRNA expression of brain-derived neurotrophic factor (BDNF) was reduced in the hippocampus. Our results suggest that impaired CB1 receptor function promotes passive stress-coping behavior, which, at least in part, might relate to alterations in BDNF function.

03/2008 | Cell Metab   IF 22.4
Paracrine activation of hepatic CB1 receptors by stellate cell-derived endocannabinoids mediates alcoholic fatty liver
Jeong W I, Osei-Hyiaman D, Park O, Liu J, Batkai S, Mukhopadhyay P, Horiguchi N, Harvey-White J, Marsicano G, Lutz B, Gao B, Kunos G

Alcohol-induced fatty liver, a major cause of morbidity, has been attributed to enhanced hepatic lipogenesis and decreased fat clearance of unknown mechanism. Here we report that the steatosis induced in mice by a low-fat, liquid ethanol diet is attenuated by concurrent blockade of cannabinoid CB1 receptors. Global or hepatocyte-specific CB1 knockout mice are resistant to ethanol-induced steatosis and increases in lipogenic gene expression and have increased carnitine palmitoyltransferase 1 activity, which, unlike in controls, is not reduced by ethanol treatment. Ethanol feeding increases the hepatic expression of CB1 receptors and upregulates the endocannabinoid 2-arachidonoylglycerol (2-AG) and its biosynthetic enzyme diacylglycerol lipase beta selectively in hepatic stellate cells. In control but not CB1 receptor-deficient hepatocytes, coculture with stellate cells from ethanol-fed mice results in upregulation of CB1 receptors and lipogenic gene expression. We conclude that paracrine activation of hepatic CB1 receptors by stellate cell-derived 2-AG mediates ethanol-induced steatosis through increasing lipogenesis and decreasing fatty acid oxidation.

03/2008 | Learn Mem   IF 2.4
Activation of CB1 specifically located on GABAergic interneurons inhibits LTD in the lateral amygdala
Azad S C, Kurz J, Marsicano G, Lutz B, Zieglgansberger W, Rammes G

Previously, we found that in the lateral amygdala (LA) of the mouse, WIN55,212-2 decreases both glutamatergic and GABAergic synaptic transmission via activation of the cannabinoid receptor type 1 (CB1), yet produces an overall reduction of neuronal excitability. This suggests that the effects on excitatory transmission override those on inhibitory transmission. Here we show that CB1 activation by WIN55,212-2 and Delta(9)-THC inhibits long-term depression (LTD) of basal synaptic transmission in the LA, induced by low-frequency stimulation (LFS; 900 pulses/1 Hz). The CB1 agonist WIN55,212-2 blocked LTD via G(i/o) proteins, activation of inwardly rectifying K+ channels (K(ir)s), inhibition of the adenylate cyclase-protein kinase A (PKA) pathway, and PKA-dependent inhibition of voltage-gated N-type Ca2+ channels (N-type VGCCs). Interestingly, WIN55,212-2 effects on LTD were abolished in CB1 knock-out mice (CB1-KO), and in conditional mutants lacking CB1 expression only in GABAergic interneurons, but were still present in mutants lacking CB1 in principal forebrain neurons. LTD induction per se was unaffected by the CB1 antagonist SR141716A and was normally expressed in CB1-KO as well as in both conditional CB1 mutants. Our data demonstrate that activation of CB1 specifically located on GABAergic interneurons inhibits LTD in the LA. These findings suggest that CB1 expressed on either glutamatergic or GABAergic neurons play a differential role in the control of synaptic transmission and plasticity.

01/2008 | J Mol Med   IF 4.7
Increased endocannabinoid levels reduce the development of precancerous lesions in the mouse colon
Izzo A A, Aviello G, Petrosino S, Orlando P, Marsicano G, Lutz B, Borrelli F, Capasso R, Nigam S, Capasso F, Di Marzo V

Colorectal cancer is an increasingly important cause of death in Western countries. Endocannabinoids inhibit colorectal carcinoma cell proliferation in vitro. In this paper, we investigated the involvement of endocannabinoids on the formation of aberrant crypt foci (ACF, earliest preneoplastic lesions) in the colon mouse in vivo. ACF were induced by azoxymethane (AOM); fatty acid amide hydrolase (FAAH) and cannabinoid receptor messenger ribonucleic acid (mRNA) levels were analyzed by the quantitative reverse transcription polymerase chain reaction (RT-PCR); endocannabinoid levels were measured by liquid chromatography-mass spectrometry; caspase-3 and caspase-9 expressions were measured by Western blot analysis. Colonic ACF formation after AOM administration was associated with increased levels of 2-arachidonoylglycerol (with no changes in FAAH and cannabinoid receptor mRNA levels) and reduction in cleaved caspase-3 and caspase-9 expression. The FAAH inhibitor N-arachidonoylserotonin increased colon endocannabinoid levels, reduced ACF formation, and partially normalized cleaved caspase-3 (but not caspase-9) expression. Notably, N-arachidonoylserotonin completely prevented the formation of ACF with four or more crypts, which have been show to be best correlated with final tumor incidence. The effect of N-arachidonoylserotonin on ACF formation was mimicked by the cannabinoid receptor agonist HU-210. No differences in ACF formation were observed between CB(1) receptor-deficient and wild-type mice. It is concluded that pharmacological enhancement of endocannabinoid levels (through inhibition of endocannabinoid hydrolysis) reduces the development of precancerous lesions in the mouse colon. The protective effect appears to involve caspase-3 (but not caspase-9) activation.