Microglia regulate learning and memory through NF-κB

Resumen del póster presentado al 19th Meeting Spanish Society of Neuroscience, celebrado en Lleida del 3 al 5 de noviembre de 2021.Microglia, the resident immune cells of the CNS, have been implicated in brain plasticity and function. However, the mechanisms remain largely unknown. Here, we show that Cre-dependent removal of the RelA subunit of the NF-κB transcription factor from adult microglia results in impaired learning and long-term potentiation. Depletion of RelA elicits changes in chromatin accessibility and transcriptome landscapes of microglia associated with specific gene regulatory programs driving the activation of specific microglia phenotypes. Our findings suggest that NF-κB gene products drive specific microglia phenotypes modulating neuronal circuits for learning and memory.Peer reviewe

Cell-specific vulnerability to metabolic failure: the crucial role of parvalbumin expressing neurons in creatine transporter deficiency

Mutations in the solute carrier family 6-member 8 (Slc6a8) gene, encoding the protein responsible for cellular creatine (Cr) uptake, cause Creatine Transporter Deficiency (CTD), an X-linked neurometabolic disorder presenting with intellectual disability, autistic-like features, and epilepsy. The pathological determinants of CTD are still poorly understood, hindering the development of therapies. In this study, we generated an extensive transcriptomic profile of CTD showing that Cr deficiency causes perturbations of gene expression in excitatory neurons, inhibitory cells, and oligodendrocytes which result in remodeling of circuit excitability and synaptic wiring. We also identified specific alterations of parvalbumin-expressing (PV+) interneurons, exhibiting a reduction in cellular and synaptic density, and a hypofunctional electrophysiological phenotype. Mice lacking Slc6a8 only in PV+ interneurons recapitulated numerous CTD features, including cognitive deterioration, impaired cortical processing and hyperexcitability of brain circuits, demonstrating that Cr deficit in PV+ interneurons is sufficient to determine the neurological phenotype of CTD. Moreover, a pharmacological treatment targeted to restore the efficiency of PV+ synapses significantly improved cortical activity in Slc6a8 knock-out animals. Altogether, these data demonstrate that Slc6a8 is critical for the normal function of PV+ interneurons and that impairment of these cells is central in the disease pathogenesis, suggesting a novel therapeutic venue for CTD.This work has been supported by grant GR-2017–02364378 funded by the Italian Ministry of Health and by Telethon grant GGP19177 to LB; Italian Ministry of Health, RC 2021; grant from Fondazione Cassa di Risparmio di Firenze “Human Brain Optical Mapping” to TP; grants from the Spanish Ministry of Science and Innovation (MICINN) co-financed by ERDF (grant no. RTI2018-102260-B-I00; Generalitat Valenciana, project no. PROMETEO/2020/007; and CSIC Interdisciplinary Thematic Platform (PTI +) NEURO-AGINGl + (PTI-NEURO-AGING +). C.M.N-I. was the recipient of a FPI fellowship from the MICINN. The Instituto de Neurociencias (UMH-CSIC) is a “Centre of Excellence Severo Ochoa” (grant no. SEV-2017–0723).Peer reviewe

Sublayer- and cell-type-specific neurodegenerative transcriptional trajectories in hippocampal sclerosis

Hippocampal sclerosis, the major neuropathological hallmark of temporal lobe epilepsy, is characterized by different patterns of neuronal loss. The mechanisms of cell-type-specific vulnerability and their progression and histopathological classification remain controversial. Using single-cell electrophysiology in vivo and immediate-early gene expression, we reveal that superficial CA1 pyramidal neurons are overactive in epileptic rodents. Bulk tissue and single-nucleus expression profiling disclose sublayer-specific transcriptomic signatures and robust microglial pro-inflammatory responses. Transcripts regulating neuronal processes such as voltage channels, synaptic signaling, and cell adhesion are deregulated differently by epilepsy across sublayers, whereas neurodegenerative signatures primarily involve superficial cells. Pseudotime analysis of gene expression in single nuclei and in situ validation reveal separated trajectories from health to epilepsy across cell types and identify a subset of superficial cells undergoing a later stage in neurodegeneration. Our findings indicate that sublayer- and cell-type-specific changes associated with selective CA1 neuronal damage contribute to progression of hippocampal sclerosis.This work was supported by grants from MICINN (RTI2018-098581-B-I00 to L.M.P.), Fundación Tatiana Pérez de Guzman el Bueno, and the SynCogDis Network (SAF2014-52624-REDT and SAF2017- 90664-REDT to L.M.P. and A. Bayes). Collaboration between L.M.d.l.P. and Y.H. was supported by Human Frontiers Science Program (HFSP) grant RGP0022/2013. J.P.L.-A. was supported by grants from MICIU co-financed by ERDF (RYC-2015-18056 and RTI2018-102260-B-I00) and Severo Ochoa grant SEV-2017-0723. R.R.-V. and A. Bayes were supported by MINECO BFU2015-69717-P and RTI2018-097037-B-100 and a Marie Curie career integration grant (ref. 304111). A.V.M. was supported by MICINN (SAF2017- 85717-R) and Fundación Alicia Koplowitz. A. Barco was supported by grants SAF2017-87928-R from MICINN co-financed by ERDF and RGP0039/2017 from the Human Frontiers Science Program Organization. The Instituto de Neurociencias is a ‘‘Centre of Excellence Severo Ochoa.’’ D.G.-D. and C.M.N. hold PhD fellowships from MICINN (BES-2013-064171 and BES2016-076281, respectively).Peer reviewe

Cannabidiol does not display drug abuse potential in mice behavior

Recent evidence suggests that cannabidiol (CBD) may be useful for the treatment of different neuropsychiatric disorders. However, some controversy regarding its profile as a drug of abuse hampers the further development of basic and clinical studies. In this study, the behavioral profile of CBD as a potential drug of abuse was evaluated in C57BL/6J mice. Reinforcing properties of CBD (15, 30, and 60 mg/kg; i.p.) were assessed using the conditioned place preference (CPP) paradigm. Spontaneous withdrawal symptoms and motor activity in the open field were examined 12 h after the last CBD administration (30 mg/kg/12 h, i.p., 6 days). CBD plasma concentrations were measured at 2, 4, 8, 12, and 24 h after the administration of CBD (30 mg/kg, i.p.). Furthermore, an oral CBD self-administration paradigm (50 mg/kg; CBD water-soluble 1.2 mg/mL) was performed to evaluate whether this drug produced any effects on motivation compared with a non-reinforcing substance (water). We found that CBD failed to induce CPP, withdrawal symptoms, or altered motor behavior 12 h after its administration. At that time, only traces of CBD were detected, ensuring that the lack of alterations in somatic signs and locomotor activity was not due to residual drug in plasma. Interestingly, mice displayed similar motivation and consumption of CBD and water. Taken together, these results show that CBD lacks activity as a drug of abuse and should stimulate the development of the basic and clinical studies needed to elucidate its potential therapeutic use for the treatment of neuropsychiatric and drug use disorders.This work was supported by the “Instituto de Salud Carlos III” (RETICS, RD12/0028/0019), “Plan Nacional Sobre Drogas” (PNSD 2016/016), and “Ministerio de Economía y Competitividad” (FIS, PI14/00438) to JM. AVM is a predoctoral fellow supported by “Plan Nacional Sobre Drogas” (PNSD 2016/016).Peer reviewe

Cannabidiol reduces ethanol consumption, motivation and relapse in mice

This study evaluated the effects of cannabidiol (CBD) on ethanol reinforcement, motivation and relapse in C57BL/6 J mice. The effects of CBD (60 mg/kg, i.p.) on blood ethanol concentration, hypothermia and handling-induced convulsions associated to acute ethanol administration were evaluated. The two-bottle choice paradigm was performed to assess the effects of CBD (30, 60 and 120 mg/kg/day, i.p.) on ethanol intake and preference. In addition, an oral ethanol self-administration experiment was carried out to evaluate the effects of CBD [a single s.c. administration of a microparticle formulation providing CBD continuous controlled release (30 mg/kg/day)] on the reinforcement and motivation for ethanol. The effects of CBD (60 and 120 mg/kg/day, i.p.) on ethanol-induced relapse were also evaluated. Gene expression analyses of tyrosine hydroxylase in ventral tegmental area and μ-opioid (Oprm1), cannabinoid (CB1 r and CB2 r) and GPR55 receptors in nucleus accumbens (NAcc) were carried out by real-time polymerase chain reaction. Cannabidiol reduced the ethanol-induced hypothermia and handling-induced convulsion but failed to modify blood ethanol concentration. CBD reduced ethanol consumption and preference in the two-bottle choice, significantly decreased ethanol intake and the number of effective responses in the oral ethanol self-administration, and reduced ethanol-induced relapse. Furthermore, the administration of CBD significantly reduced relative gene expression of tyrosine hydroxylase in the ventral tegmental area, Oprm1, CB1 r and GPR55 in the NAcc and significantly increased CB2 r in the NAcc. Taken together, these results reveal that the administration of CBD reduced the reinforcing properties, motivation and relapse for ethanol. These findings strongly suggest that CBD may result useful for the treatment of alcohol use disorders.This research was supported by ‘Instituto de Salud Carlos III’ (RETICS, RD12/0028/0019), ‘Plan Nacional Sobre Drogas’ (PNSD 2016/016) and ‘Ministerio de Economía y Competitividad’ (FIS, PI14/00438). Adrián Viudez-Martínez is a predoctoral fellow supported by ‘Plan Nacional Sobre Drogas’ (PNSD 2016/016).Peer reviewe

KAT3-dependent acetylation of cell type-specific genes maintains neuronal identity in the adult mouse brain

The lysine acetyltransferases type 3 (KAT3) family members CBP and p300 are important transcriptional co-activators, but their specific functions in adult post-mitotic neurons remain unclear. Here, we show that the combined elimination of both proteins in forebrain excitatory neurons of adult mice resulted in a rapidly progressing neurological phenotype associated with severe ataxia, dendritic retraction and reduced electrical activity. At the molecular level, we observed the downregulation of neuronal genes, as well as decreased H3K27 acetylation and pro-neural transcription factor binding at the promoters and enhancers of canonical neuronal genes. The combined deletion of CBP and p300 in hippocampal neurons resulted in the rapid loss of neuronal molecular identity without de- or transdifferentiation. Restoring CBP expression or lysine acetylation rescued neuronal-specific transcription in cultured neurons. Together, these experiments show that KAT3 proteins maintain the excitatory neuron identity through the regulation of histone acetylation at cell type-specific promoter and enhancer regions.M.L. is recipient of a Santiago Grisolia fellowship given by the Generalitat Valenciana, J.M.C. is recipient of a fellowship from the Spanish Ministry of Education, Culture and Sport (MECD), J.F.-A. and C.M.N. are recipients of fellowships from the Spanish Ministry of Science and Innovation (MICINN). The ultrastructure research was supported by the Polish National Science Center Grant UMO-2014/15/N/NZ3/04468 and by the European Regional Development Fund POIG 01.01.02-00-008/08. J.P.L.-A. research is supported by Grants RYC-2015-18056 and RTI2018-102260-B-I00 from MICINN co-financed by ERDF. A.B. research is supported by Grants SAF2017-87928-R, PCIN-2015-192-C02-01, and SEV-2017-0723 from MICINN co-financed by ERDF, PROMETEO/2016/026 from the Generalitat Valenciana, and RGP0039/2017 from the Human Frontiers Science Program Organization (HFSPO). The Instituto de Neurociencias is a “Centre of Excellence Severo Ochoa”.Peer reviewe

Sublayer- and cell-type-specific neurodegenerative transcriptional trajectories in hippocampal sclerosis

Hippocampal sclerosis, the major neuropathological hallmark of temporal lobe epilepsy, is characterized by different patterns of neuronal loss. The mechanisms of cell-type-specific vulnerability and their progression and histopathological classification remain controversial. Using single-cell electrophysiology in vivo and immediate-early gene expression, we reveal that superficial CA1 pyramidal neurons are overactive in epileptic rodents. Bulk tissue and single-nucleus expression profiling disclose sublayer-specific transcriptomic signatures and robust microglial pro-inflammatory responses. Transcripts regulating neuronal processes such as voltage channels, synaptic signaling, and cell adhesion are deregulated differently by epilepsy across sublayers, whereas neurodegenerative signatures primarily involve superficial cells. Pseudotime analysis of gene expression in single nuclei and in situ validation reveal separated trajectories from health to epilepsy across cell types and identify a subset of superficial cells undergoing a later stage in neurodegeneration. Our findings indicate that sublayer- and cell-type-specific changes associated with selective CA1 neuronal damage contribute to progression of hippocampal sclerosis.Sin financiación9.423 JCR (2020) Q1, 33/195 Cell Biology6.264 SJR (2020) Q1, 7/253 Biochemistry, Genetics and Molecular Biology (miscellaneous)No data IDR 2019UE