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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).

Synapses are centrally involved in many brain disorders, particularly in psychiatric and neurodevelopmental ones. However, our current understanding of the proteomic alterations affecting synaptic performance in the majority of mental illnesses is limited. As a result, novel pharmacotherapies with improved neurological efficacy have been scarce over the past decades. The main goal of synaptic proteomics in the context of mental illnesses is to identify dysregulated molecular mechanisms underlying these conditions. Here we reviewed and performed a meta-analysis of previous neuroproteomic research to identify proteins that may be consistently dysregulated in one or several mental disorders. Notably, we found very few proteins reproducibly altered among independent experiments for any given condition or between conditions, indicating that we are still far from identifying key pathophysiological mechanisms of mental illness. We suggest that future research in the field will require higher levels of standardization and larger-scale experiments to address the challenge posed by biological and methodological variability. We strongly believe that more resources should be placed in this field as the need to identify the molecular roots of mental illnesses is highly pressing.

© 2019 Elsevier Inc. Synapses are fundamental information-processing units of the brain, and synaptic dysregulation is central to many brain disorders (“synaptopathies”). However, systematic annotation of synaptic genes and ontology of synaptic processes are currently lacking. We established SynGO, an interactive knowledge base that accumulates available research about synapse biology using Gene Ontology (GO) annotations to novel ontology terms: 87 synaptic locations and 179 synaptic processes. SynGO annotations are exclusively based on published, expert-curated evidence. Using 2,922 annotations for 1,112 genes, we show that synaptic genes are exceptionally well conserved and less tolerant to mutations than other genes. Many SynGO terms are significantly overrepresented among gene variations associated with intelligence, educational attainment, ADHD, autism, and bipolar disorder and among de novo variants associated with neurodevelopmental disorders, including schizophrenia. SynGO is a public, universal reference for synapse research and an online analysis platform for interpretation of large-scale -omics data (https://syngoportal.org and http://geneontology.org). The SynGO consortium presents a framework to annotate synaptic protein locations and functions and annotations for 1,112 synaptic genes based on published experimental evidence. SynGO reports exceptional features and disease associations for synaptic genes and provides an online data analysis platform.

The SynGAP protein is a major regulator of synapse biology and neural circuit function. Genetic variants linked to epilepsy and intellectual disability disrupt synaptic function and neural excitability. SynGAP has been involved in multiple signaling pathways and can regulate small GTPases with very different roles. Yet, the molecular bases behind this pleiotropy are poorly understood. We hypothesize that different SynGAP isoforms will mediate different sets of functions and that deciphering their spatio‐temporal expression and subcellular localization will accelerate understanding their multiple functions. Using isoform‐specific antibodies recognizing SynGAP in mouse and human samples we found distinctive developmental expression patterns for all SynGAP isoforms in five mouse brain areas. Particularly noticeable was the delayed expression of SynGAP‐α1 isoforms, which directly bind to postsynaptic density‐95, in cortex and hippocampus during the first 2 weeks of postnatal development. Suggesting that during this period other isoforms would have a more prominent role. Furthermore, we observed subcellular localization differences between isoforms, particularly throughout postnatal development. Consistent with previous reports, SynGAP was enriched in the postsynaptic density in the mature forebrain. However, SynGAP was predominantly found in non‐synaptic locations in a period of early postnatal development highly sensitive to SynGAP levels. While, α1 isoforms were always found enriched in the postsynaptic density, α2 isoforms changed from a non‐synaptic to a mostly postsynaptic density localization with age and β isoforms were always found enriched in non‐synaptic locations. The differential expression and subcellular distribution of SynGAP isoforms may contribute to isoform‐specific regulation of small GTPases, explaining SynGAP pleiotropy., Syngap1 gene encodes for different synaptic Ras/Rap GTPase‐activating (SynGAP) isoforms which are key for brain function. SynGAP C‐termini splice variants show different spatio‐temporal expression and subcellular localization in the developing mouse brain. This study reveals a non‐synaptic and heterogenous role of SynGAP spliced variants. Depicted abundance differences only allow relative comparison within a given tissue (top panel), postnatal age (PND, middle panel), or subcellular distribution (bottom panel). Ctx, cortex; Hip, hippocampus; Str, striatum; OB, Olfactory Bulb; Crb, cerebellum and tSynGAP, total SynGAP.

Cannabis is the most consumed illicit drug worldwide. Its principal psychoactive component, Δ9-tetrahydrocannabinol (THC), affects multiple brain functions, including cognitive performance, by modulating cannabinoid type-1 (CB1) receptors. These receptors are strongly enriched in presynaptic terminals, where they modulate neurotransmitter release. We analyzed, through a proteomic screening of hippocampal synaptosomal fractions, those proteins and pathways modulated 3 h after a single administration of an amnesic dose of THC (10 mg/kg, i.p.). Using an isobaric labeling approach, we identified 2040 proteins, 1911 of them previously reported in synaptic proteomes, confirming the synaptic content enrichment of the samples. Initial analysis revealed a significant alteration of 122 proteins, where 42 increased and 80 decreased their expression. Gene set enrichment analysis indicated an over-representation of mitochondrial associated functions and cellular metabolic processes. A second analysis focusing on extreme changes revealed 28 proteins with altered expression after THC treatment, 15 of them up-regulated and 13 down-regulated. Using a network topology-based scoring algorithm we identified those proteins in the mouse proteome with the greatest association to the 28 modulated proteins. This analysis pinpointed a significant alteration of the proteasome function, since top scoring proteins were related to the proteasome system (PS), a protein complex involved in ATP-dependent protein degradation. In this regard, we observed that THC decreases 20S proteasome chymotrypsin-like protease activity in the hippocampus. Our data describe for the first time the modulation of the PS in the hippocampus following THC administration under amnesic conditions that may contribute to an aberrant plasticity at synapses. This study was supported by Grants from the Ministerio de Economía, Innovación y Competitividad (MINECO) (#BFU2015-68568-P (MINECO/FEDER, UE) to A.O., #BFU2015-69717-P (MINECO/FEDER, UE) to RRV and AB, #RYC-2011-08391 to AB, #SAF2017-90664-REDT to RRV and AB, #SAF2014-59648-P and #SAF2017-84060-R to R.M.; a grant from the Instituto de Salud Carlos III (#RD16/0017/0020) to R.M.; Generalitat de Catalunya (2017SGR-669 to R.M. and 2017SGR1776 to RRV and AB) and ICREA (Institució Catalana de Recerca i Estudis Avançats) Academia to A.O. and R.M. Mass spectrometric analyses were performed at the CRG/UPF Proteomics Unit which is part of the of Proteored, PRB3 and is supported by grant PT17/0019, of the PE I + D + i 2013-2016, funded by ISCIII and ERDF. Grant “Unidad de Excelencia María de Maeztu”, funded by the MINECO (#MDM-2014-0370); PLAN E (Plan Español para el Estímulo de la Economía y el Empleo); FEDER funding is also acknowledged

The role of telomere shortening to explain the occurrence of Robertsonian (Rb) fusions, as well as the importance of the average telomere length vs. the proportion of short telomeres, especially in nature populations, is largely unexplored. In this study, we have analysed telomere shortening in nine wild house mice from the Barcelona Rb system with diploid numbers ranging from 29 to 40 chromosomes. We also included two standard (2n=40) laboratory mice for comparison. Our data showed that the average telomere length (considering all chromosomal arms) is influenced by both the diploid number and the origin of the mice (wild vs. laboratory). In detail, we detected that wild mice from the Rb Barcelona system (fused and standard) present shorter telomeres than standard laboratory mice. However, only wild mice with Rb fusions showed a high proportion of short telomeres (only in p-arms), thus revealing the importance of telomere shortening in the origin of the Rb fusions in the Barcelona system. Overall, our study confirms that the number of critically short telomeres, and not a simple reduction in the average telomere length, is more likely to lead to the origin of Rb fusions in the Barcelona system and ultimately in nature.

IntroductionThe methodological guides for the assessment of new/emerging non-pharmacological technologies differ from the traditional health technology assessment (HTA) guidelines developed by the Spanish Network of Agencies for Assessing National Health System Technologies and Performance (RedETS). The aim of this study is to identify the special features and challenges of carrying out HTA on new/emergent non-pharmacological technologies.MethodsThe application of traditional and new/emergent HTA guidelines is compared along the consecutive evaluation phases in four practical cases carried out at the Agency for Health Quality and Assessment of Catalonia (AQuAS) in 2017-2018.ResultsMain learning and outstanding challenges: (i) Instead of following a defined protocol, the evaluations are carried out from a preliminary short report which generates a lack of justification and delimitation of its scope. (ii) References’ identification and data extraction are often limited due to lack of studies, and sometimes require the use of grey literature or other sources less informative, for example, trial registries. It can be challenging to exclude references related to other indications. (iii) The assessment of resource use and costs of running the technology is complicated due to the lack of public prices information and specific impacts of use. (iv) The evidence considered during the assessment usually does not meet high quality requirements (risk of bias) because of indirect evidence, lack of comparator or no having clearly defined outcomes, among others. (v) It's difficult to draw conclusions and, consequently, recommendations due to abovementioned aspects and especially for the usual evidence gap that faces this type of technology in early stages of diffusion and/or in a competition situation of manufacturer companies.ConclusionsThe most recent innovation in non-pharmacological technologies merits a differentiated assessment approach. However, there is need to reconsider the methodology applied in order to overcome the challenges and limitations identified.

The proteome of human brain synapses is highly complex and is mutated in over 130 diseases. This complexity arose from two whole-genome duplications early in the vertebrate lineage. Zebrafish are used in modelling human diseases; however, its synapse proteome is uncharacterized, and whether the teleost-specific genome duplication (TSGD) influenced complexity is unknown. We report the characterization of the proteomes and ultrastructure of central synapses in zebrafish and analyse the importance of the TSGD. While the TSGD increases overall synapse proteome complexity, the postsynaptic density (PSD) proteome of zebrafish has lower complexity than mammals. A highly conserved set of ∼1,000 proteins is shared across vertebrates. PSD ultrastructural features are also conserved. Lineage-specific proteome differences indicate that vertebrate species evolved distinct synapse types and functions. The data sets are a resource for a wide range of studies and have important implications for the use of zebrafish in modelling human synaptic diseases., Systematic analysis of the zebrafish synapse proteome has been lacking. Here the authors characterize the ultrastructure of zebrafish synapse and compare the proteomes of postsynaptic density in zebrafish and mice, offering a resource for future studies using zebrafish to model diseases.

Telomeres protect against genome instability and participate in chromosomal movements during gametogenesis, especially in meiosis. Thus, maintaining telomere structure and telomeric length is essential to both cell integrity and the production of germ cells. As a result, alteration of telomere homeostasis in the germ line may result in the generation of aneuploid gametes or gametogenesis disruption, triggering fertility problems. In this work, we provide an overview on fundamental aspects of the literature regarding the organization of telomeres in mammalian germ cells, paying special attention to telomere structure and function, as well as the maintenance of telomeric length during gametogenesis. Moreover, we discuss the different roles recently described for telomerase and TERRA in maintaining telomere functionality. Finally, we review how new findings in the field of reproductive biology underscore the role of telomere homeostasis as a potential biomarker for infertility. Overall, we anticipate that the study of telomere stability and equilibrium will contribute to improve diagnoses of patients; assess the risk of infertility in the offspring; and in turn, find new treatments.

Telomeres are ribonucleoprotein structures at the end of chromosomes composed of telomeric DNA, specific-binding proteins, and noncoding RNA (TERRA). Despite their importance in preventing chromosome instability, little is known about the cross talk between these three elements during the formation of the germ line. Here, we provide evidence that both TERRA and the telomerase enzymatic subunit (TERT) are components of telomeres in mammalian germ cells. We found that TERRA colocalizes with telomeres during mammalian meiosis and that its expression progressively increases during spermatogenesis until the beginning of spermiogenesis. While both TERRA levels and distribution would be regulated in a gender-specific manner, telomere-TERT colocalization appears to be regulated based on species-specific characteristics of the telomeric structure. Moreover, we found that TERT localization at telomeres is maintained throughout spermatogenesis as a structural component without affecting telomere elongation. Our results represent the first evidence of colocalization between telomerase and telomeres during mammalian gametogenesis.

What is the distribution of telomeric repeat-containing RNA (TERRA) and of telomerase in human fetal oocytes?TERRA forms discrete foci at telomeres of human fetal oocytes and it co-localizes with both the shelterin component telomeric repeat-binding factor 2 (TRF2) and the catalytic subunit of human telomerase at the telomeres of meiotic chromosomes.TERRA is a structural element of the telomeric chromatin that has been described in somatic cells of many different eukaryote species. The telomerase enzyme is inactive in adult somatic cells but is active in germ cells, stem cells and in the majority of tumors; however, its distribution in oocytes is still unknown.For this study, ovarian samples from four euploid fetuses of 22 gestational weeks were used. These samples were obtained with the consent of the parents and of the Ethics Committee of Hospital de la Vall d'Hebron.We analyzed the distribution of TERRA and telomerase in cells derived from human fetal ovaries. The co-localization of TERRA, telomerase and telomeres was performed by optimizing a combination of immunofluorescence (IF) and RNA-fluorescent in situ hybridization (RNA-FISH) techniques. The synaptonemal complex protein 3 (SYCP3), TRF2 and protein component of telomerase [telomerase reverse transcriptase (TERT)] were detected by IF, whereas TERRA was revealed by RNA-FISH using a (CCCTAA)(3) oligonucleotide. SYCP3 signals allowed us to identify oocytes that had entered meiosis and classify them into the different stages of prophase I, whereas TRF2 indicated the telomeric regions of chromosomes.We show for the first time the presence of TERRA and the intracellular distribution of telomerase in human fetal ovarian cells. TERRA is present, forming discrete foci, in 75% of the ovarian tissue cells and most of TERRA molecules (≈ 83%) are at telomeres (TRF2 co-localization). TERRA levels are higher in oocytes than in ovarian tissue cells (P = 0.00), and do not change along the progression of the prophase I stage (P = 0.37). TERRA is present on ≈ 23% of the telomeres in all cell types derived from human fetal ovaries. Moreover, ≈ 22% of TERRA foci co-localize with the protein component of telomerase (TERT).We present a descriptive/qualitative study of TERRA in human fetal ovarian tissue. Given the difficult access and manipulation of fetal samples, the number of fetal ovaries used in this study was limited.This is the first report on TERRA expression in oocytes from human fetal ovaries. The presence of TERRA at the telomeres of oocytes from the leptotene to pachytene stages and its co-localization with the telomerase protein component suggests that this RNA might participate in the maintenance of the telomere structure, at least through the processes that take place during the female meiotic prophase I. Since telomeres in oocytes have been mainly studied regarding the bouquet structure, our results introduce a new viewpoint of the telomeric structure during meiosis.

Bisphenol A (BPA) is a 'weak' endocrine disruptor. The effect of BPA on human reproduction is controversial but has been related to meiotic anomalies, recurrent spontaneous abortion, abnormal karyotypes, the diminishing of oocyte survival, delay in meiotic pro- gression and an elevated rate of MLH1 foci in vitro. The aim of this study is to characterize the gene expression of human fetal oocytes in culture as well as to evaluate the effect of BPA in cultured human oocytes. To accomplish our objective, 12 ovaries from 6 euploid fetuses were used. The ovarian fetal tissue was cultivated in two groups: control group and BPA group (BPA30 mM). The cultures were analyzed at T0 and after 7 (T7), 14 (T14) and 21 (T21) days of culture. Evaluation of gene expression was performed by real-time PCR (RT -PCR), with the evaluated genes being: Smc1b, Sycp1 (pairing-synapsis), Spo11, Rpa, H2ax, Mlh1 and Blm (double-strand break (DSBs) generation, sig- naling and repair), Era, Erb and Errg (estrogen receptors), Stra8 and Nalp5 (markers of meiotic progression). Oocytes from ovaries cultured and treated with BPA show changes in the expression of Spo11, H2ax and Blm genes, with a significant increase from 3- to 5-fold (P ≤ 0.05). Finally, Rpa, showed a 100-fold increment (P ≤ 0.01). Era, Erb and Errg genes showed a BPA up-regulation of 2 -4-fold in all of the culture times (P ≤ 0.05). Oocytes exposed to BPA showed an up-regulation of genes involved in DSB generation, signaling and repair except by Mlh1. Thus, BPA can modify the gene expression pattern, which may explain the effects of BPA on female germ cells.

Objective To study whether the telomere structure of germ cells from idiopathic infertile men is altered and if this impairment is influenced by meiotic recombination and telomere length. Design We performed a detailed analysis of both telomeric repeat-containing RNA (TERRA) and telomerase distribution in testis cell spreads by combining immunofluorescence and RNA fluorescent in situ hybridization. In addition we analyzed meiotic recombination between homologous chromosomes by immunofluorescence and telomere length by quantitative fluorescent in situ hybridization. Setting University. Patient(s) Men consulting for fertility problems. Intervention(s) Unilateral testicular biopsies. Main Outcome Measure(s) We observed that TERRA levels and its nuclear distribution were compromised in infertile patients. In addition, the presence of the protein component of telomerase at telomeres decreased in the affected patients. However, neither telomerase-TERRA association nor telomere length was altered in spermatocytes I of infertile samples compared with control individuals. In addition, we observed that meiotic recombination was reduced in infertile individuals. Result(s) Telomere homeostasis is impaired in infertile patients, and this was translated into a decrease in TERRA levels together with an alteration of the TERRA-protein component of telomerase telomeric association in primary spermatocytes. Conclusion(s) This study demonstrates for the first time that telomere structure and homeostasis in germ cells is compromised in infertile individuals. In the light of our results we propose that the analysis of telomeric structure (i.e., TERRA levels and telomere association with TERRA and telomerase) would provide new tools for our understanding of the origin of human infertility.