Cannabinoids, eating behaviour, and energy homeostasis

Soon after the discovery of cannabis by western societies, its psychotropic effects overshadowed its medical benefits. How-ever, investigation into the molecular action of the main constituents of cannabis has led to the discovery of an intercellularsignalling system, called the endocannabinoid system (ECS). The ECS comprises a set of molecular components, including en-zymes, signalling lipids and G-protein coupled receptors, which has an outstanding role in modulating eating behaviour andenergy homeostasis. Interestingly, evidence has shown that the ECS is present at the central and peripheral nervous system,modulating the function of the hypothalamus, the brain reward system and the brainstem, and coordinating the crosstalk be-tween these brain structures and peripheral organs. Indeed, the ECS is present and functional in metabolically relevant periph-eral tissues, directly modulating their physiology. In the context of a global obesity pandemic, these discoveries are highlysuggestive in order to design novel pharmaceutical tools to fight obesity and related morbidities. In fact, a cannabinoid-based first generation of drugs was developed and marketed. Their failure, due to central side-effects, is leading to a secondgeneration of these drugs unable to cross the blood–brain barrier, as well as other ECS-focused strategies that are still in thepipeline. In the next few years we will hopefully know whether such an important player in energy homeostasis can be suc-cessfully targeted without significantly affecting other vital processes related to mood and sense of well-being

The role of the endocannabinoid system in eating disorders: pharmacological implications

The endocannabinoid (eCB) system is a widespread intercellular signalling mechanism that plays a critical role in body homoeostasis. It is located in key points involved in food intake and energy expenditure, coordinating all the players involved in energy balance. As such, it has come to be seen as an interesting target for the management of diseases characterized by an imbalanced energy homoeostasis, such as obesity and eating disorders. The aetiology of eating disorders and the molecular systems involved are still largely a mystery. Research has focused on brain circuits where the eCB system plays an important role, such as those related to feeding behaviour and the rewarding properties of food. Accordingly, recent findings have suggested a deregulation of the eCB system in eating disorders. At present, cannabinoid agonists are safe and effective tools in the management of diseases in which weight gain is needed, for example cachexia in AIDS patients. However, studies on the potential therapeutic validity of cannabinoids in eating disorders are scarce and inconclusive. Taken together, all these considerations warrant more preclinical and clinical investigations in the role of the eCB system in eating disorders. Eventually, they may provide novel pharmacological approaches for the treatment of these diseases

Enhanced markers of oxidative stress, altered antioxidants and NADPH-oxidase activation in brains from Fragile X mental retardation 1-deficient mice, a pathological model for Fragile X syndrome.

Política de acceso abierto tomada de: https://v2.sherpa.ac.uk/id/publication/6992Fragile X syndrome is the most common form of inherited mental retardation in humans. It originates from the loss of expression ofthe Fragile X mental retardation 1 (FMR1) gene, which results in the absence of the Fragile X mental retardation protein. However,the biochemical mechanisms involved in the pathological phenotype are mostly unknown. The availability of the FMR1-knockoutmouse model offers an excellent model system in which to study the biochemical alterations related to brain abnormalities in thesyndrome. We show for the first time that brains from Fmr1-knockout mice, a validated model for the syndrome, display higher levelsof reactive oxygen species, nicotinamide adenine dinucleotide phosphate (NADPH)-oxidase activation, lipid peroxidation and proteinoxidation than brains from wild-type mice. Furthermore, the antioxidant system is deficient in Fmr1-knockout mice, as shown byaltered levels of components of the glutathione system. FMR1-knockout mice lacking Fragile X mental retardation protein werecompared with congenic FVB129 wild-type controls. Our results support the hypothesis that the lack of Fragile X mental retardationprotein function leads to a moderate increase of the oxidative stress status in the brain that may contribute to the pathophysiology ofthe Fragile X syndrome

Alpha-tocopherol protects against oxidative stress in the fragile X knockout mouse: an experimental therapeutic approach for the Fmr1 deficiency.

Política de acceso abierto tomada de: https://v2.sherpa.ac.uk/id/publication/4027Fragile X syndrome is the most common genetic cause of mental disability. The mechanisms underlying the pathogenesis remain unclear and specific treatments are still under development. Previous studies have proposed an abnormal hypothalamic–pituitary–adrenal axis and high cortisol levels are demonstrated in the fragile X patients. Additionally, we have previously described that NADPH-oxidase activation leads to oxidative stress in the brain, representing a pathological mechanism in the fragile X mouse model. Fmr1-knockout mice develop an altered free radical production, abnormal glutathione homeostasis, high lipid and protein oxidation, accompanied by stress-dependent behavioral abnormalities and pathological changes in the first months of postnatal life. Chronic pharmacological treatment with α-tocopherol reversed pathophysiological hallmarks including free radical overproduction, oxidative stress, Rac1 and α-PKC activation, macroorchidism, and also behavior and learning deficits. The restoration of the oxidative status in the fragile X mouse emerges as a new and promising approach for further therapeutic research in fragile X syndrome

Early maternal deprivation induces gender-dependent changes on the expression of hippocampal CB(1) and CB(2) cannabinoid receptors of neonatal rats.

Política de acceso abierto tomada de: https://v2.sherpa.ac.uk/id/publication/13858Early maternal deprivation (MD) in rats (24 h, postnatal day 9–10) is a model for neurodevelopmental stress. There are some data proving that MD affects the endocannabinoid system (ECS) in a gender-dependent manner, and that these changes may account for the proposed schizophrenia-like phenotype of MD rats. The impact of MD on cannabinoid receptor distribution in the hippocampus is unknown. The aim of this study is to evaluate the expression of CB1 and CB2 receptors in diverse relevant subregions (DG, CA1, and CA3) of the hippocampus in 13-day-old rats by immunohistochemistry and densitometry. MD induced a significant decrease in CB1 immunoreactivity (more marked in males than in females), which was mainly associated with fibers in the strata pyramidale and radiatum of CA1 and in the strata oriens, pyramidale, and radiatum of CA3. In contrast, MD males and females showed a significant increase in CB2 immunoreactivity in the three hippocampal areas analyzed that was detected in neuropil and puncta in the stratum oriens of CA1 and CA3, and in the polymorphic cell layer of the dentate gyrus. A marked sex dimorphism was observed in CA3, with females exhibiting higher CB1 immunoreactivity than males, and in dentate gyrus, with females exhibiting lower CB2 immunoreactivity than males. These results point to a clear association between developmental stress and dysregulation of the ECS. The present MD procedure may provide an interesting experimental model to further address the role of the ECS in neurodevelopmental mental illnesses such as schizophrenia. © 2008 Wiley-Liss, Inc.Consejería de Salud. Grant Number: PI-0220 Consejería de Innovación, Ciencia y Empresa. Grant Number: P05-CV1-1038 (Junta de Andalucía) Ministerio de Sanidad y Consumo. Grant Numbers: 2006/142, FIS 07/1226 Ministerio de Educación y Ciencia. Grant Number: SAF2006-07523 Red de trastornos adictivos. Grant Number: RD06/0001 Plan Nacional sobre Droga

New molecular mechanisms to explain the neuroprotective effects of insulin-like growth factor II in a cellular model of Parkinson's disease

Introduction: One of the hallmarks of Parkinsońs Disease (PD) is oxidative distress, leading to mitochondrial dysfunction and neurodegeneration. Insulin-like growth factor II (IGF-II) has been proven to have antioxidant and neuroprotective effects in some neurodegenerative diseases, including PD. Consequently, there isgrowing interest in understanding the different mechanisms involved in the neuroprotective effect of this hormone. Objectives: To clarify the mechanism of action of IGF-II involved in the protective effect of this hormone. Methods: The present study was carried out on a cellular model PD based on the incubation of dopaminergic cells (SN4741) in a culture with the toxic 1-methyl-4-phenylpyridinium (MPP+), in the presence of IGF-II. This model undertakes proteomic analyses in order to understand which molecular cell pathways might be involved in the neuroprotective effect of IGF-II. The most important proteins found in the proteomic study were tested by Western blot, colorimetric enzymatic activity assay and immunocytochemistry. Along with the proteomic study, mitochondrial morphology and function were also studied by transmission electron microscopy and oxygen consumption rate. The cell cycle was also analysed using 7AAd/BrdU staining, and flow cytometry. Results: The results obtained indicate that MPP+, MPP++IGF-II treatment and IGF-II, when compared to control, modified the expression of 197, 246 proteins and 207 respectively. Some of these proteins were found to be involved in mitochondrial structure and function, and cell cycle regulation. Including IGF-II in the incubation medium prevents the cell damage induced by MPP+, recovering mitochondrial function and cell cycle dysregulation, and thereby decreasing apoptosis. Conclusion: IGF-II improves mitochondrial dynamics by promoting the association of Mitofilin with mitochondria, regaining function and redox homeostasis. It also rebalances the cell cycle, reducing the amount of apoptosis and cell death by the regulation of transcription factors, such as Checkpoint kinase 1

Overexpression of Cannabinoid CB2 Receptor in the Brain Induces Hyperglycaemia and a Lean Phenotype in Adult Mice

t is well known that the endocannabinoid system, through cannabinoid CB1 receptor activation,has an important role in the main aspects of energy balance (i.e. food intake, energy expenditureand glucose and fat metabolism), orchestrating all the machinery involved in body weight con-trol and energy homeostasis. A number of studies have revealed a crucial role of brain CB1receptors in these processes. However, functional cannabinoid CB2 receptors have also beendescribed in the brain, with no studies addressing their putative role in body weight control andglucose homeostasis. We have tested this hypothesis by analysing fasting-induced feeding, bodyweight, some hypothalamic neuropeptides, glucose tolerance and plasma hormones in an animalmodel specifically overexpressing CB2 receptors in the central nervous system. We found thatspecific overexpression of CB2 receptors in the brain promoted higher basal glucose levels,decreased fasting-induced feeding and, eventually, led to a lean phenotype and glucose intoler-ance. These findings could not be attributed to decreased locomotor activity, increased anxietyor depressive-like behaviours. The expression of relevant neuropeptides such as pro-opiomelano-cortin and galanin in the arcuate nucleus of the hypothalamus was altered but not those of theCB1 receptor. Indeed, no changes in CB1 expression were found in the liver, skeletal muscle andadipose tissue. However, cannabinoid CB1 and CB2 receptor expression in the endocrine pan-creas and glucagon plasma levels were decreased. No changes in plasma adiponectin, leptin,insulin and somatostatin were found. Taken together, these results suggest a role for centralcannabinoid CB2 receptors in body weight control and glucose homeostasis

Cocaine detrimentally affects mitochondrial functionality and cell viability in dopaminergic neurons.

An elevated consumption of cocaine (benzoylmethylecgonine), which causes anesthetic and stimulant effects on the central nervous system, may be associated with several neurodegenerative conditions affecting dopaminergic neurons, such as Parkinson's disease (PD). To investigate the impact of cocaine on cell viability and morphology, dopaminergic neurons from the substantia nigra (SN4741) were cultured. Analysis involved assessing cell death (LDH levels) and cell morphology (GIEMSA staining) after a 24-hour treatment period. Additionally, the effects on reactive oxygen species (ROS) generation (DH2), membrane potential (JC-1), oxygen consumption rate (OCR), and mitochondrial stress (Seahorse) were evaluated after a 6-hour treatment. The optimal concentration of cocaine for experimental use (2 mM) was identified, inducing a substantial 39.75% neuronal death. Examination of neuronal death (LDH) revealed a remarkable 280% increase following cocaine treatment. Optical analysis demonstrated heightened mortality and detrimental changes in neuronal morphology post-cocaine treatment, including a globose shape, loss of synapses, extremely thin membrane, and cell aggregation. In the "short time" experiments, mitochondrial oxidative damage was evident in SN cells treated with cocaine, leading to the demise of 75% of the cells. Furthermore, a significant 173.6% increase in reactive oxygen species (ROS) production and a 20% reduction in mitochondrial membrane potential (JC-1 assay) were observed. Cocaine treatment also resulted in a notable 60% decrease in mitochondrial oxygen consumption. In summary, a concentration of 2 mM cocaine induces a considerable rise in mitochondrial oxidative damage, subsequently causing morphological alterations and progressive death of dopaminergic neurons due to the accumulation of reactive oxygen species (ROS).Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Antioxidant and neuroprotective actions of IGF-II against glucocorticoid-induced toxicity in dopaminergic neurons.

The neurodegenerative Parkinson’s disease (PD) affects 1–3% of the population aged over 65. A wide range of pathways and mechanisms are involved in its pathogenesis, such as oxidative stress, mitochondrial dysfunction, inflammation and neuronal glucocorticoid-induced toxicity, which ultimately produce a progressive loss of nigral dopamine neurons. Insulin-like growth factor II (IGF-II) has shown antioxidant and neuroprotective effects in some neurodegenerative disorders. Therefore, our aim was to study IGF-II protective effects against oxidative damage on a cellular combined model of PD and mild to moderate stress, based on corticosterone (CORT), an endocrine response marker to stress, and the dopaminergic neurotoxin 1-methyl-4-phenylpyridinium (MPP+). The dopaminergic neuronal cell line SN4741 (RRID:CVCL_S466) derived from mouse substantia nigra were exposed to 200 μM MPP+, 0.5 μM CORT or both, with or without 25 ng/mL IGF-II, for 2.5 or 6 h. Cell viability, oxidative stress parameters, mitochondrial and dopamine markers and intracellular signaling pathways were evaluated. The administration of MPP+ or CORT individually led to cell damage compared to control situations, whereas the combination of both drugs produced very considerable toxic synergistic effect. IGF-II counteracts the mitochondrial-oxidative damage, protecting dopaminergic neurons from death and neurodegeneration. IGF-II maintained the tyrosine hydroxylase expression and promotes nuclear factor (erythroid-derived 2)-like 2 antioxidant response in a glucocorticoid receptor-dependent pathway, preventing oxidative cell damage and maintaining mitochondrial function. This work revealed the potential neuroprotective role of IGF-II to protect nigral dopamine neurons against mitochondrial-oxidative damage induced by CORT and MPP+ was demonstrated. Thus, IGF-II is a potential therapeutic tool for prevention and treatment of PD patients suffering mild to moderate emotional stress.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

RPL13A and EEF1A1 Are Suitable Reference Genes for qPCR during Adipocyte Differentiation of Vascular Stromal Cells from Patients with Different BMI and HOMA-IR

Real-time or quantitative PCR (qPCR) is a useful technique that requires reliable reference genes for data normalization in gene expression analysis. Adipogenesis is among the biological processes suitable for this technique. The selection of adequate reference genes is essential for qPCR gene expression analysis of human Vascular Stromal Cells (hVSCs) during their differentiation into adipocytes. To the best of our knowledge, there are no studies validating reference genes for the analyses of visceral and subcutaneous adipose tissue hVSCs from subjects with different Body Mass Index (BMI) and Homeostatic Model Assessment of Insulin Resistance (HOMA-IR) index. The present study was undertaken to analyze this question. We first analyzed the stability of expression of five potential reference genes: CYC, GAPDH, RPL13A, EEF1A1, and 18S ribosomal RNA, during in vitro adipogenic differentiation, in samples from these types of patients. The expression of RPL13A and EEF1A1 was not affected by differentiation, thus being these genes the most stable candidates, while CYC, GAPDH, and 18S were not suitable for this sort of analysis. This work highlights that RPL13A and EEF1A1 are good candidates as reference genes for qPCR analysis of hVSCs differentiation into adipocytes from subjects with different BMI and HOMA-IR.Instituto de Salud Carlos III (PI10/01947, PI13/02628) with Fondos FEDER and the Consejería de Economía e Innovación, Ciencia y Empleo, Junta de Andalucía (CTS-7895) with Fondos FEDER. R. El Bekay is under a contract Miguel Servet type II (CPII13/00041) from the Instituto de Salud Carlos III. F-JB-S is a recipient of a "Miguel Servet II" research contract (CPII13/00042) and also belongs to the regional "Nicolás Monardes" research program of the Consejería de Salud (C-0070-2012; Junta de Andalucía, Spain). This work was supported by the FIS-Thematic Networks and Co-Operative Research Centres RIRAAF (RD07-0064). JM is under the Programa de Intensificación de la Actividad Investigadora del Sistema Nacional de Salud. AV-R is under a contract Proyectos de I+D+i para jóvenes investigadores from the Ministerio de Economía y Competitividad (SAF2014-60649-JIN). S-YR-Z is recipient of a post-doctoral contract from Consejería de Salud de la Junta de Andalucía (RH-0070-2013)