Involvement of the endogenous opioid and cannabinoid systems in addictive like behaviours

Grau académico estrangeiro - BiomedicinaABSTRACT: The increase incidence of obesity and eating disorders represents a major health problem in developed countries. The low rate of success of treatments to prevent or reverse obesity, and overeating that causes it, highlights the important behavioural alterations that are associated to this disease. These alterations seem to be mediated by modifications in the reward circuits that mimic changes occurring during addictive behaviour. Moreover, like drugs of abuse, obesity is associated with abnormal intake habits when maintaining diet that can endure vulnerability to relapse. In the present thesis, we have first investigated the involvement of the endogenous opioid system in the neurobiological mechanism underlying drug and food reinstatement, as a potential therapeutic target in these behavioural disorders. Moreover, we have investigated the relationships between overeating and behavioural addiction. Indeed, we have demonstrated that repeated operant training with palatable food promotes behavioural alterations, as well as epigenetic, proteomic and structural plasticity changes in the reward circuit reminiscent to those observed with drugs of abuse. Finally, we identified the cannabinoid receptor 1 and the delta opioid receptor as common neurobiological substrates underlying these alterations.RESUMEN: El aumento de la incidencia de la obesidad y de los trastornos de la alimentación representa un importante problema de salud en los países desarrollados. La baja tasa de éxito de los tratamientos disponibles para prevenir o revertir la obesidad y el fácil acceso a la comida obesogenica que lo causa, destacan la necesidad de encentrar dianas terapéuticas eficaces. Las importantes alteraciones conductuales que se asocian a esta enfermedad parecen estar mediadas por modificaciones en los circuitos de recompensa que imitan los cambios que ocurren durante el comportamiento adictivo. Por otra parte, al igual que las drogas de abuso, la obesidad se asocia con hábitos de ingesta anormales que pueden incrementar la vulnerabilidad a la recaída de búsqueda de comida. En la presente tesis, hemos investigado primero la implicación del sistema opioide endógeno en el mecanismo neurobiológico que subyace a la recaída del comportamiento de búsqueda de drogas y comida como una posible diana terapéutica en estos trastornos del comportamiento. En segundo lugar, hemos investigado las relaciones entre la sobre ingesta de comida palatable y la adicción conductual. De hecho, hemos demostrado que el entrenamiento operante repetido con comida palatable promueve alteraciones de la conducta, así como cambios epigenéticos, proteómicos y de plasticidad estructural en el circuito de la recompensa que recuerdan a los observados con las drogas de abuso. Es destacable señalar que hemos identificado el receptor cannabinoide 1 y el receptor delta opioide como sustratos neurobiológicos comunes que subyacen a estas alteraciones

Imprinting fidelity in mouse iPSCs depends on sex of donor cell and medium formulation

Funding Information: We would like to thank Sérgio de Almeida, Miguel Casanova and Inês Milagre for critical reading of the manuscript, and the members of the S.T.d.R.’s team for helpful discussions. We also thank Tânia Carvalho and Pedro Ruivo for their help in histological analysis; Judith Webster at Babraham Institute for LC-MS measurements; Bethan Hussey at Sanger Sequencing and Kristina Tabbada at Babraham Institute for assistance with high-throughput sequencing; and the Bioimaging unit as well as Andreia Santos, Rute Gonçalves and Mariana Fernandes of the Flow Cytometry Facility of Instituto de Medicina Molecular João Lobo Antunes for their services and assistance. Work in S.T.d.R.’s team was supported by Fundação para a Ciência e Tecnologia (FCT) Ministério da Ciência, Tecnologia e Ensino Superior (MCTES), Portugal [IC&DT projects PTDC/BEX-BCM/2612/2014 and PTDC/BIA-MOL/29320/2017 as well as projects UIDB/04565/2020 and UIDP/04565/2020 of the Research Unit Institute from Bioengineering and Biosciences – iBB and LA/P/0140/2020 of the Associate Laboratory Institute for Health and Bioeconomy – i4HB]; S.T.d.R. and A.-V.G. are supported by assistant research contracts from FCT/MCTES (CEECIND/01234/2017 and CEECIND/02085/2018, respectively); M.A and A.C.R. are supported, respectively, by SFRH/BD/151251/2021 and SFRH/BD/137099/2018 PhD fellowships from FCT/MCTES. J.V.G.L is supported by COVID/BD/152624/2022 from FCT/MCTES. MAE-M was supported by a BBSRC Discovery Fellowship (BB/T009713/1) and is now supported by a Snow Medical Fellowship. F.K. is supported by the Babraham Institute Strategic Core Funding and A.M. by BBSRC BBS/E/B/000C0421. B.B.J. work was funded by Fundação para a Ciência e Tecnologia (FCT), and FEDER, LISBOA-01-0145-FEDER-028534, project co-funded by FEDER, through POR Lisboa 2020—Programa Operacional Regional de Lisboa. T.K. is supported by Janko Jamnik Doctoral Scholarship from National Institute of Chemistry. Funding Information: We would like to thank Sérgio de Almeida, Miguel Casanova and Inês Milagre for critical reading of the manuscript, and the members of the S.T.d.R.’s team for helpful discussions. We also thank Tânia Carvalho and Pedro Ruivo for their help in histological analysis; Judith Webster at Babraham Institute for LC-MS measurements; Bethan Hussey at Sanger Sequencing and Kristina Tabbada at Babraham Institute for assistance with high-throughput sequencing; and the Bioimaging unit as well as Andreia Santos, Rute Gonçalves and Mariana Fernandes of the Flow Cytometry Facility of Instituto de Medicina Molecular João Lobo Antunes for their services and assistance. Work in S.T.d.R.’s team was supported by Fundação para a Ciência e Tecnologia (FCT) Ministério da Ciência, Tecnologia e Ensino Superior (MCTES), Portugal [IC&DT projects PTDC/BEX-BCM/2612/2014 and PTDC/BIA-MOL/29320/2017 as well as projects UIDB/04565/2020 and UIDP/04565/2020 of the Research Unit Institute from Bioengineering and Biosciences – iBB and LA/P/0140/2020 of the Associate Laboratory Institute for Health and Bioeconomy – i4HB]; S.T.d.R. and A.-V.G. are supported by assistant research contracts from FCT/MCTES (CEECIND/01234/2017 and CEECIND/02085/2018, respectively); M.A and A.C.R. are supported, respectively, by SFRH/BD/151251/2021 and SFRH/BD/137099/2018 PhD fellowships from FCT/MCTES. J.V.G.L is supported by COVID/BD/152624/2022 from FCT/MCTES. MAE-M was supported by a BBSRC Discovery Fellowship (BB/T009713/1) and is now supported by a Snow Medical Fellowship. F.K. is supported by the Babraham Institute Strategic Core Funding and A.M. by BBSRC BBS/E/B/000C0421. B.B.J. work was funded by Fundação para a Ciência e Tecnologia (FCT), and FEDER, LISBOA-01-0145-FEDER-028534, project co-funded by FEDER, through POR Lisboa 2020—Programa Operacional Regional de Lisboa. T.K. is supported by Janko Jamnik Doctoral Scholarship from National Institute of Chemistry. Publisher Copyright: © 2022, The Author(s).Reprogramming of somatic cells into induced Pluripotent Stem Cells (iPSCs) is a major leap towards personalised approaches to disease modelling and cell-replacement therapies. However, we still lack the ability to fully control the epigenetic status of iPSCs, which is a major hurdle for their downstream applications. Epigenetic fidelity can be tracked by genomic imprinting, a phenomenon dependent on DNA methylation, which is frequently perturbed in iPSCs by yet unknown reasons. To try to understand the causes underlying these defects, we conducted a thorough imprinting analysis using IMPLICON, a high-throughput method measuring DNA methylation levels, in multiple female and male murine iPSC lines generated under different experimental conditions. Our results show that imprinting defects are remarkably common in iPSCs, but their nature depends on the sex of donor cells and their response to culture conditions. Imprints in female iPSCs resist the initial genome-wide DNA demethylation wave during reprogramming, but ultimately cells accumulate hypomethylation defects irrespective of culture medium formulations. In contrast, imprinting defects on male iPSCs depends on the experimental conditions and arise during reprogramming, being mitigated by the addition of vitamin C (VitC). Our findings are fundamental to further optimise reprogramming strategies and generate iPSCs with a stable epigenome.publishersversionpublishe

Role of DOR in neuronal plasticity changes promoted by food-seeking behaviour

Several lines of evidence support that food overconsumption may be related to the role of the endogenous opioid system in the control of food palatability. The opioid system, and particularly the delta opioid receptor (DOR), plays a crucial role in the regulation of food rewarding properties. In our study, we used operant conditioning maintained by chocolate-flavoured pellets to investigate the role of DOR in the motivation for palatable food and the structural plasticity changes promoted by this behaviour. For this purpose, we evaluated the specific role of this receptor in the behavioural and neuroplastic changes induced by palatable food in the prefrontal cortex (PFC), hippocampus (HCP) and nucleus accumbens (NAc) in constitutive knockout (KO) mice deficient in DOR. Mutant mice and their wild-type littermates were trained to obtain chocolate-flavoured pellets on fixed ratio 1 (FR1), FR5 and progressive ratio (PR) schedule of reinforcement. No significant differences between genotypes were revealed on operant behaviour acquisition in FR1. DOR knockout mice displayed lower number of active lever-presses than wild-type mice on FR5, and a similar decrease was revealed in DOR KO mice in the breaking point during the PR. This operant training to obtain palatable food increased dendritic spine density in the PFC, HCP and NAc shell of wild-type, but these plasticity changes were abolished in DOR KO mice. Our results support the hypothesis that DOR regulates the reinforcing effects and motivation for palatable food through neuroplastic changes in specific brain reward areas.This work was supported by the DG Research of the European Commission FP7 (#HEALTH-F2 2013-602891), the Spanish ‘RETICS-Instituto de Salud Carlos III’ (#RD12/0028/0023), the Spanish ‘Ministerio de Ciencia e Innovación’ (#SAF2011-29864), the Spanish ‘Ministerio de Economia y Competitividad’ (#SAF-2014-59648P), the ‘Plan nacional sobre drogas’ (#PNSD-2013-5068) and the Catalan Government ‘AGAUR-Generalitat de Catalunya’ (#2009SGR00731 and #2014-SGR-1547). The FEDER funds support is also acknowledged. S.M. was supported by FI predoctoral fellowship of the Catalan Government; S.M-N. was supported by CAPES fellowship of the Brazilian Government (Programa Ciência Sem Froteiras). We thank Elysia James for invaluable technical assistance in the structural plasticity stud

A specific prelimbic-nucleus accumbens pathway controls resilience versus vulnerability to food addiction

Food addiction is linked to obesity and eating disorders and is characterized by a loss of behavioral control and compulsive food intake. Here, using a food addiction mouse model, we report that the lack of cannabinoid type-1 receptor in dorsal telencephalic glutamatergic neurons prevents the development of food addiction-like behavior, which is associated with enhanced synaptic excitatory transmission in the medial prefrontal cortex (mPFC) and in the nucleus accumbens (NAc). In contrast, chemogenetic inhibition of neuronal activity in the mPFC-NAc pathway induces compulsive food seeking. Transcriptomic analysis and genetic manipulation identified that increased dopamine D2 receptor expression in the mPFC-NAc pathway promotes the addiction-like phenotype. Our study unravels a new neurobiological mechanism underlying resilience and vulnerability to the development of food addiction, which could pave the way towards novel and efficient interventions for this disorder.This work was supported by the Spanish Ministerio de Economía y Competitividad-MINECO (#SAF2017-84060-R-AEI/FEDER-UE), the Spanish Instituto de Salud Carlos III, RETICS-RTA (#RD12/0028/0023), the Generalitat de Catalunya, AGAUR (#2017 SGR-669), ICREA-Acadèmia (#2015) and the Spanish Ministerio de Sanidad, Servicios Sociales e Igualdad, Plan Nacional Sobre Drogas (#PNSD-2017I068) to R.M., Fundació La Marató-TV3 (#2016/20-30) to E.M-G., the German Research Foundation (#CRC1193 “Neurobiology of Resilience”, TP A05 and B04) to B.L. and S.G., and the Boehringer Ingelheim Foundation to B.L., S.G. and I.R.A. The work of M.N.A was supported by the Emergent AI Center funded by the Carl-Zeiss-Stiftung. NARSAD Young Investigator Award (#22434), MINECO Ramón y Cajal (#RYC- 2014-15784) and (#SAF2016-76565-R) and Fondo Europeo de Desarrollo Regional (FEDER) to R.A. DIUE Generalitat de Catalunya (#2017 SGR 595), MINECO (#SAF2016-79956-R), EU (#Era Net Neuron PCIN-2013-060), Fundació La Marató-TV3 (#2016/20-31), CRG acknowledges support of the Spanish Ministry of Economy, Industry and Competitiveness (MEIC) to the EMBL partnership, the Center of Excellence Severo Ochoa (#SEV-2012-0208), the CERCA Programme/Generalitat de Catalunya, the CIBER of Rare Diseases of the ISCIII to M.D. MINECO Ramón y Cajal (#RYC-2016-20414), AGAUR (#2017 SGR 926), (#RTI2018-094887-B-I00) and Fondo Europeo de Desarrollo Regional (FEDER) to M.N

Epigenetic and proteomic expression changes promoted by eating addictive-like behavior

An increasing perspective conceptualizes obesity and overeating as disorders related to addictive-like processes that could share common neurobiological mechanisms. In the present study, we aimed at validating an animal model of eating addictive-like behavior in mice, based on the DSM-5 substance use disorder criteria, using operant conditioning maintained by highly palatable chocolate-flavored pellets. For this purpose, we evaluated persistence of food-seeking during a period of non-availability of food, motivation for food, and perseverance of responding when the reward was associated with a punishment. This model has allowed identifying extreme subpopulations of mice related to addictive-like behavior. We investigated in these subpopulations the epigenetic and proteomic changes. A significant decrease in DNA methylation of CNR1 gene promoter was revealed in the prefrontal cortex of addict-like mice, which was associated with an upregulation of CB1 protein expression in the same brain area. The pharmacological blockade (rimonabant 3 mg/kg; i.p.) of CB1 receptor during the late training period reduced the percentage of mice that accomplished addiction criteria, which is in agreement with the reduced performance of CB1 knockout mice in this operant training. Proteomic studies have identified proteins differentially expressed in mice vulnerable or not to addictive-like behavior in the hippocampus, striatum, and prefrontal cortex. These changes included proteins involved in impulsivity-like behavior, synaptic plasticity, and cannabinoid signaling modulation, such as alpha-synuclein, phosphatase 1-alpha, doublecortin-like kinase 2, and diacylglycerol kinase zeta, and were validated by immunoblotting. This model provides an excellent tool to investigate the neurobiological substrate underlying the vulnerability to develop eating addictive-like behavior.This work was supported by the DG Research of the European Commission FP7 (No. HEALTH-F2 2013-602891), the Spanish ‘RETICS-Instituto de Salud Carlos III’ (No. RD12/0028/0023), the Spanish ‘Ministerio de Ciencia e Innovación’ (No. SAF2011-29864), and the Catalan Government ‘AGAUR-Generalitat de Catalunya’ (Nos. 2009SGR00731 and 2014-SGR-1547). The FEDER funds support is also acknowledged. SM and AB were supported by FI predoctoral fellowships of the Catalan Government, and JG-C was supported by a ‘Juan de la Cierva’ postdoctoral fellowship from the Spanish ‘Ministerio de Ciencia e Innovación’. Also support by the Italian Ministry of University and Research under grants FIRB-RBFR12DELS to CDA and PRIN2010-11 to MM is gratefully acknowledged. The authors declare no conflict of interest

Effects on the incidence of cardiovascular events of the addition of pioglitazone versus sulfonylureas in patients with type 2 diabetes inadequately controlled with metformin (TOSCA.IT): a randomised, multicentre trial

Background The best treatment option for patients with type 2 diabetes in whom treatment with metformin alone fails to achieve adequate glycaemic control is debated. We aimed to compare the long-term effects of pioglitazone versus sulfonylureas, given in addition to metformin, on cardiovascular events in patients with type 2 diabetes. Methods TOSCA.IT was a multicentre, randomised, pragmatic clinical trial, in which patients aged 50\ue2\u80\u9375 years with type 2 diabetes inadequately controlled with metformin monotherapy (2\ue2\u80\u933 g per day) were recruited from 57 diabetes clinics in Italy. Patients were randomly assigned (1:1), by permuted blocks randomisation (block size 10), stratified by site and previous cardiovascular events, to add-on pioglitazone (15\ue2\u80\u9345 mg) or a sulfonylurea (5\ue2\u80\u9315 mg glibenclamide, 2\ue2\u80\u936 mg glimepiride, or 30\ue2\u80\u93120 mg gliclazide, in accordance with local practice). The trial was unblinded, but event adjudicators were unaware of treatment assignment. The primary outcome, assessed with a Cox proportional-hazards model, was a composite of first occurrence of all-cause death, non-fatal myocardial infarction, non-fatal stroke, or urgent coronary revascularisation, assessed in the modified intention-to-treat population (all randomly assigned participants with baseline data available and without any protocol violations in relation to inclusion or exclusion criteria). This study is registered with ClinicalTrials.gov, number NCT00700856. Findings Between Sept 18, 2008, and Jan 15, 2014, 3028 patients were randomly assigned and included in the analyses. 1535 were assigned to pioglitazone and 1493 to sulfonylureas (glibenclamide 24 [2%], glimepiride 723 [48%], gliclazide 745 [50%]). At baseline, 335 (11%) participants had a previous cardiovascular event. The study was stopped early on the basis of a futility analysis after a median follow-up of 57\uc2\ub73 months. The primary outcome occurred in 105 patients (1\uc2\ub75 per 100 person-years) who were given pioglitazone and 108 (1\uc2\ub75 per 100 person-years) who were given sulfonylureas (hazard ratio 0\uc2\ub796, 95% CI 0\uc2\ub774\ue2\u80\u931\uc2\ub726, p=0\uc2\ub779). Fewer patients had hypoglycaemias in the pioglitazone group than in the sulfonylureas group (148 [10%] vs 508 [34%], p<0\uc2\ub70001). Moderate weight gain (less than 2 kg, on average) occurred in both groups. Rates of heart failure, bladder cancer, and fractures were not significantly different between treatment groups. Interpretation In this long-term, pragmatic trial, incidence of cardiovascular events was similar with sulfonylureas (mostly glimepiride and gliclazide) and pioglitazone as add-on treatments to metformin. Both of these widely available and affordable treatments are suitable options with respect to efficacy and adverse events, although pioglitazone was associated with fewer hypoglycaemia events. Funding Italian Medicines Agency, Diabete Ricerca, and Italian Diabetes Society