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1.
Nat Commun ; 11(1): 4901, 2020 09 29.
Artigo em Inglês | MEDLINE | ID: mdl-32994410

RESUMO

Myelin, rather than being a static insulator of axons, is emerging as an active participant in circuit plasticity. This requires precise regulation of oligodendrocyte numbers and myelination patterns. Here, by devising a laser ablation approach of single oligodendrocytes, followed by in vivo imaging and correlated ultrastructural reconstructions, we report that in mouse cortex demyelination as subtle as the loss of a single oligodendrocyte can trigger robust cell replacement and remyelination timed by myelin breakdown. This results in reliable reestablishment of the original myelin pattern along continuously myelinated axons, while in parallel, patchy isolated internodes emerge on previously unmyelinated axons. Therefore, in mammalian cortex, internodes along partially myelinated cortical axons are typically not reestablished, suggesting that the cues that guide patchy myelination are not preserved through cycles of de- and remyelination. In contrast, myelin sheaths forming continuous patterns show remarkable homeostatic resilience and remyelinate with single axon precision.


Assuntos
Córtex Cerebral/metabolismo , Bainha de Mielina/metabolismo , Oligodendroglia/metabolismo , Animais , Axônios/metabolismo , Córtex Cerebral/citologia , Feminino , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Oligodendroglia/citologia , Remielinização
2.
PLoS One ; 15(9): e0238037, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32886703

RESUMO

Spectral Counts approaches (SpCs) are largely employed for the comparison of protein expression profiles in label-free (LF) differential proteomics applications. Similarly, to other comparative methods, also SpCs based approaches require a normalization procedure before Fold Changes (FC) calculation. Here, we propose new Complexity Based Normalization (CBN) methods that introduced a variable adjustment factor (f), related to the complexity of the sample, both in terms of total number of identified proteins (CBN(P)) and as total number of spectral counts (CBN(S)). Both these new methods were compared with the Normalized Spectral Abundance Factor (NSAF) and the Spectral Counts log Ratio (Rsc), by using standard protein mixtures. Finally, to test the robustness and the effectiveness of the CBNs methods, they were employed for the comparative analysis of cortical protein extract from zQ175 mouse brains, model of Huntington Disease (HD), and control animals (raw data available via ProteomeXchange with identifier PXD017471). LF data were also validated by western blot and MRM based experiments. On standard mixtures, both CBN methods showed an excellent behavior in terms of reproducibility and coefficients of variation (CVs) in comparison to the other SpCs approaches. Overall, the CBN(P) method was demonstrated to be the most reliable and sensitive in detecting small differences in protein amounts when applied to biological samples.


Assuntos
Biomarcadores/metabolismo , Córtex Cerebral/metabolismo , Modelos Animais de Doenças , Doença de Huntington/metabolismo , Proteoma/análise , Animais , Biomarcadores/análise , Córtex Cerebral/patologia , Proteínas de Escherichia coli/metabolismo , Doença de Huntington/patologia , Camundongos , Camundongos Endogâmicos C57BL , Modelos Teóricos , Padrões de Referência , Reprodutibilidade dos Testes , Espectrometria de Massas em Tandem
3.
Adv Exp Med Biol ; 1255: 231-247, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32949404

RESUMO

The single-cell RNA sequencing (scRNA-seq) is a powerful tool for exploring the complexity, clusters, and specific functions of the brain cells. Using scRNA-seq, the heterogeneity and changes in transcriptomic profiles of a single neuron were defined during dynamic development and differentiation of cells in cerebral cortex regions, and in the pathogenesis of neurological diseases. One of the great challenges is that the brain sample is susceptible to interference and confounding. More advanced methodologies of computational systems biology need to be developed to overcome the inherent interference and technical differences in the detection of single-cell signals. It is expected that scRNA-seq will be extended to metabolic profiles of the single neuron cell on basis of transcriptional profiles and regulatory networks. It is also expected if the transcriptional profiles can be integrated with molecular and functional phenomes in a single neuron and with disease-specific phenomes to understand molecular mechanisms of brain development and disease occurrence. scRNA-seq will provide the new emerging neurological disciple of the artificial intelligent single neuron for deep understanding of brain diseases.


Assuntos
Córtex Cerebral/embriologia , Córtex Cerebral/metabolismo , RNA-Seq , Análise de Célula Única , Encefalopatias/genética , Encefalopatias/metabolismo , Encefalopatias/patologia , Córtex Cerebral/citologia , Humanos , Transcriptoma
4.
PLoS One ; 15(8): e0237066, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32780740

RESUMO

TLR4 is a member of the toll-like receptors (TLR) immune family, which are activated by lipopolysaccharide, ethanol or damaged tissue, among others, by triggering proinflammatory cytokines release and inflammation. Lack of TLR4 protects against inflammatory processes and neuroinflammation linked with several neuropathologies. By considering that miRNAs are key post-transcriptional regulators of the proteins involved in distinct cellular processes, including inflammation, this study aimed to assess the impact of the miRNAs profile in mice cortices lacking the TLR4 response. Using mice cerebral cortices and next-generation sequencing (NGS), the findings showed that lack of TLR4 significantly reduced the quantity and diversity of the miRNAs expressed in WT mice cortices. The results also revealed a significant down-regulation of the miR-200 family, while cluster miR-99b/let-7e/miR-125a was up-regulated in TLR4-KO vs. WT. The bioinformatics and functional analyses demonstrated that TLR4-KO presented the systematic depletion of many pathways closely related to the immune system response, such as cytokine and interleukin signaling, MAPK and ion Channels routes, MyD88 pathways, NF-κß and TLR7/8 pathways. Our results provide new insights into the molecular and biological processes associated with the protective effects of TLR-KO against inflammatory damage and neuroinflammation, and reveal the relevance of the TLR4 receptors response in many neuropathologies.


Assuntos
Córtex Cerebral/metabolismo , MicroRNAs/genética , Receptor 4 Toll-Like/genética , Animais , Citocinas/metabolismo , Feminino , Regulação da Expressão Gênica/genética , Inflamação/genética , Inflamação/metabolismo , Lipopolissacarídeos , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Transdução de Sinais , Receptor 4 Toll-Like/metabolismo , Transcriptoma/genética
5.
Mol Cell ; 79(3): 443-458.e7, 2020 08 06.
Artigo em Inglês | MEDLINE | ID: mdl-32649883

RESUMO

Despite the prominent role of TDP-43 in neurodegeneration, its physiological and pathological functions are not fully understood. Here, we report an unexpected role of TDP-43 in the formation of dynamic, reversible, liquid droplet-like nuclear bodies (NBs) in response to stress. Formation of NBs alleviates TDP-43-mediated cytotoxicity in mammalian cells and fly neurons. Super-resolution microscopy reveals distinct functions of the two RRMs in TDP-43 NB formation. TDP-43 NBs are partially colocalized with nuclear paraspeckles, whose scaffolding lncRNA NEAT1 is dramatically upregulated in stressed neurons. Moreover, increase of NEAT1 promotes TDP-43 liquid-liquid phase separation (LLPS) in vitro. Finally, we discover that the ALS-associated mutation D169G impairs the NEAT1-mediated TDP-43 LLPS and NB assembly, causing excessive cytoplasmic translocation of TDP-43 to form stress granules, which become phosphorylated TDP-43 cytoplasmic foci upon prolonged stress. Together, our findings suggest a stress-mitigating role and mechanism of TDP-43 NBs, whose dysfunction may be involved in ALS pathogenesis.


Assuntos
Esclerose Amiotrófica Lateral/genética , Proteínas de Ligação a DNA/genética , Corpos de Inclusão Intranuclear/metabolismo , Neurônios/metabolismo , RNA Longo não Codificante/genética , Esclerose Amiotrófica Lateral/metabolismo , Esclerose Amiotrófica Lateral/patologia , Animais , Animais Geneticamente Modificados , Arsenitos/farmacologia , Córtex Cerebral/efeitos dos fármacos , Córtex Cerebral/metabolismo , Córtex Cerebral/ultraestrutura , Grânulos Citoplasmáticos/efeitos dos fármacos , Grânulos Citoplasmáticos/metabolismo , Grânulos Citoplasmáticos/ultraestrutura , Proteínas de Ligação a DNA/metabolismo , Modelos Animais de Doenças , Drosophila melanogaster , Regulação da Expressão Gênica , Células HEK293 , Células HeLa , Humanos , Corpos de Inclusão Intranuclear/efeitos dos fármacos , Corpos de Inclusão Intranuclear/ultraestrutura , Camundongos , Mutação , Neurônios/efeitos dos fármacos , Neurônios/ultraestrutura , Cultura Primária de Células , Transporte Proteico/efeitos dos fármacos , RNA Longo não Codificante/metabolismo , Transdução de Sinais , Estresse Fisiológico
6.
PLoS Comput Biol ; 16(7): e1008099, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32706788

RESUMO

Next-generation sequencing (NGS) technology has become a powerful tool for dissecting the molecular and pathological signatures of a variety of human diseases. However, the limited availability of biological samples from different disease stages is a major hurdle in studying disease progressions and identifying early pathological changes. Deep learning techniques have recently begun to be applied to analyze NGS data and thereby predict the progression of biological processes. In this study, we applied a deep learning technique called generative adversarial networks (GANs) to predict the molecular progress of Alzheimer's disease (AD). We successfully applied GANs to analyze RNA-seq data from a 5xFAD mouse model of AD, which recapitulates major AD features of massive amyloid-ß (Aß) accumulation in the brain. We examined how the generator is featured to have specific-sample generation and biological gene association. Based on the above observations, we suggested virtual disease progress by latent space interpolation to yield the transition curves of various genes with pathological changes from normal to AD state. By performing pathway analysis based on the transition curve patterns, we identified several pathological processes with progressive changes, such as inflammatory systems and synapse functions, which have previously been demonstrated to be involved in the pathogenesis of AD. Interestingly, our analysis indicates that alteration of cholesterol biosynthesis begins at a very early stage of AD, suggesting that it is the first effect to mediate the cholesterol metabolism of AD downstream of Aß accumulation. Here, we suggest that GANs are a useful tool to study disease progression, leading to the identification of early pathological signatures.


Assuntos
Doença de Alzheimer/fisiopatologia , RNA-Seq , Algoritmos , Doença de Alzheimer/genética , Precursor de Proteína beta-Amiloide/genética , Animais , Encéfalo/metabolismo , Córtex Cerebral/metabolismo , Colesterol/metabolismo , Análise por Conglomerados , Aprendizado Profundo , Modelos Animais de Doenças , Progressão da Doença , Humanos , Inflamação , Camundongos , Modelos Genéticos , RNA Mensageiro/metabolismo , Sinapses/metabolismo , Lobo Temporal/metabolismo , Sequenciamento Completo do Exoma
7.
Life Sci ; 257: 118037, 2020 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-32622942

RESUMO

Palmitoylethanolamide (PEA) is an endogenous lipid mediator that, also by blunting astrocyte activation, demonstrated beneficial properties in several in vitro and in vivo models of Alzheimer's disease (AD). In the present study, we used astrocyte-neuron co-cultures from 3xTg-AD mouse (i.e. an animal model of AD) cerebral cortex to further investigate on the role of astrocytes in PEA-induced neuroprotection. To this aim, we evaluated the number of viable cells, apoptotic nuclei, microtubule-associated protein-2 (MAP2) positive cells and morphological parameters in cortical neurons co-cultured with cortical astrocytes pre-exposed, or not, to Aß42 (0.5 µM; 24 h) or PEA (0.1 µM; 24 h). Pre-exposure of astrocytes to Aß42 failed to affect the viability, the number of neuronal apoptotic nuclei, MAP2 positive cell number, neuritic aggregations/100 µm, dendritic branches per neuron, the neuron body area, the length of the longest dendrite and number of neurites/neuron in 3xTg-AD mouse astrocyte-neuron co-cultures. Compared to neurons from wild-type (non-Tg) mouse co-cultures, 3xTg-AD mouse neurons co-cultured with astrocytes from this mutant mice displayed higher number of apoptotic nuclei, lower MAP2 immunoreactivity and several morphological changes. These signs of neuronal suffering were significantly counteracted when the 3xTg-AD mouse cortical neurons were co-cultured with 3xTg-AD mouse astrocytes pre-exposed to PEA. The present data suggest that in astrocyte-neuron co-cultures from 3xTg-AD mice, astrocytes contribute to neuronal damage and PEA, by possibly counteracting reactive astrogliosis, improved neuronal survival. These findings further support the role of PEA as a possible new therapeutic opportunity in AD treatment.


Assuntos
Astrócitos/efeitos dos fármacos , Astrócitos/metabolismo , Etanolaminas/farmacologia , Ácidos Palmíticos/farmacologia , Doença de Alzheimer/tratamento farmacológico , Doença de Alzheimer/metabolismo , Peptídeos beta-Amiloides/metabolismo , Animais , Sobrevivência Celular/efeitos dos fármacos , Córtex Cerebral/metabolismo , Técnicas de Cocultura , Modelos Animais de Doenças , Etanolaminas/metabolismo , Gliose , Humanos , Masculino , Camundongos , Camundongos Transgênicos , Proteínas Associadas aos Microtúbulos , Neurônios/efeitos dos fármacos , Fármacos Neuroprotetores/farmacologia , Ácidos Palmíticos/metabolismo , Proteínas tau/metabolismo
8.
Neurology ; 95(2): e140-e154, 2020 07 14.
Artigo em Inglês | MEDLINE | ID: mdl-32591470

RESUMO

OBJECTIVE: To compare the sensitivity of structural MRI and 18F-fludeoxyglucose PET (18FDG-PET) to detect longitudinal changes in frontotemporal dementia (FTD). METHODS: Thirty patients with behavioral variant FTD (bvFTD), 7 with nonfluent/agrammatic variant primary progressive aphasia (nfvPPA), 16 with semantic variant primary progressive aphasia (svPPA), and 43 cognitively normal controls underwent 2-4 MRI and 18FDG-PET scans (total scans/visit = 270) as part of the Frontotemporal Lobar Degeneration Neuroimaging Initiative study. Linear mixed-effects models were carried out voxel-wise and in regions of interest to identify areas showing decreased volume or metabolism over time in patients as compared to controls. RESULTS: At baseline, patients with bvFTD showed bilateral temporal, dorsolateral, and medial prefrontal atrophy/hypometabolism that extended with time into adjacent structures and parietal lobe. In nfvPPA, baseline atrophy/hypometabolism in supplementary motor cortex extended with time into left greater than right precentral, dorsolateral, and dorsomedial prefrontal cortex. In svPPA, baseline atrophy/hypometabolism encompassed the anterior temporal and medial prefrontal cortex and longitudinal changes were found in temporal, orbitofrontal, and lateral parietal cortex. Across syndromes, there was substantial overlap in the brain regions showing volume and metabolism loss. Even though the pattern of metabolic decline was more extensive, metabolic changes were also more variable and sample size estimates were similar or higher for 18FDG-PET compared to MRI. CONCLUSION: Our findings demonstrated the sensitivity of 18FDG-PET and structural MRI for tracking disease progression in FTD. Both modalities showed highly overlapping patterns of longitudinal change and comparable sample size estimates to detect longitudinal changes in future clinical trials.


Assuntos
Demência Frontotemporal/diagnóstico por imagem , Demência Frontotemporal/metabolismo , Idoso , Atrofia , Córtex Cerebral/diagnóstico por imagem , Córtex Cerebral/metabolismo , Progressão da Doença , Feminino , Fluordesoxiglucose F18 , Demência Frontotemporal/psicologia , Humanos , Estudos Longitudinais , Imagem por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Neuroimagem , Testes Neuropsicológicos , Tomografia por Emissão de Pósitrons , Compostos Radiofarmacêuticos
9.
Proc Natl Acad Sci U S A ; 117(25): 13886-13895, 2020 06 23.
Artigo em Inglês | MEDLINE | ID: mdl-32522880

RESUMO

Elucidating the lineage relationships among different cell types is key to understanding human brain development. Here we developed parallel RNA and DNA analysis after deep sequencing (PRDD-seq), which combines RNA analysis of neuronal cell types with analysis of nested spontaneous DNA somatic mutations as cell lineage markers, identified from joint analysis of single-cell and bulk DNA sequencing by single-cell MosaicHunter (scMH). PRDD-seq enables simultaneous reconstruction of neuronal cell type, cell lineage, and sequential neuronal formation ("birthdate") in postmortem human cerebral cortex. Analysis of two human brains showed remarkable quantitative details that relate mutation mosaic frequency to clonal patterns, confirming an early divergence of precursors for excitatory and inhibitory neurons, and an "inside-out" layer formation of excitatory neurons as seen in other species. In addition our analysis allows an estimate of excitatory neuron-restricted precursors (about 10) that generate the excitatory neurons within a cortical column. Inhibitory neurons showed complex, subtype-specific patterns of neurogenesis, including some patterns of development conserved relative to mouse, but also some aspects of primate cortical interneuron development not seen in mouse. PRDD-seq can be broadly applied to characterize cell identity and lineage from diverse archival samples with single-cell resolution and in potentially any developmental or disease condition.


Assuntos
Linhagem da Célula , Córtex Cerebral/citologia , Neurogênese , Córtex Cerebral/crescimento & desenvolvimento , Córtex Cerebral/metabolismo , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Acúmulo de Mutações , Células-Tronco Neurais/citologia , Células-Tronco Neurais/metabolismo , Análise de Sequência de DNA , Análise de Célula Única
10.
PLoS Genet ; 16(6): e1008775, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32492070

RESUMO

Late-Onset Alzheimer's disease (LOAD) is a common, complex genetic disorder well-known for its heterogeneous pathology. The genetic heterogeneity underlying common, complex diseases poses a major challenge for targeted therapies and the identification of novel disease-associated variants. Case-control approaches are often limited to examining a specific outcome in a group of heterogenous patients with different clinical characteristics. Here, we developed a novel approach to define relevant transcriptomic endophenotypes and stratify decedents based on molecular profiles in three independent human LOAD cohorts. By integrating post-mortem brain gene co-expression data from 2114 human samples with LOAD, we developed a novel quantitative, composite phenotype that can better account for the heterogeneity in genetic architecture underlying the disease. We used iterative weighted gene co-expression network analysis (WGCNA) to reduce data dimensionality and to isolate gene sets that are highly co-expressed within disease subtypes and represent specific molecular pathways. We then performed single variant association testing using whole genome-sequencing data for the novel composite phenotype in order to identify genetic loci that contribute to disease heterogeneity. Distinct LOAD subtypes were identified for all three study cohorts (two in ROSMAP, three in Mayo Clinic, and two in Mount Sinai Brain Bank). Single variant association analysis identified a genome-wide significant variant in TMEM106B (p-value < 5×10-8, rs1990620G) in the ROSMAP cohort that confers protection from the inflammatory LOAD subtype. Taken together, our novel approach can be used to stratify LOAD into distinct molecular subtypes based on affected disease pathways.


Assuntos
Doença de Alzheimer/genética , Genes Modificadores , Transcriptoma , Idoso , Idoso de 80 Anos ou mais , Doença de Alzheimer/patologia , Córtex Cerebral/metabolismo , Córtex Cerebral/patologia , Feminino , Perfilação da Expressão Gênica/métodos , Heterogeneidade Genética , Estudo de Associação Genômica Ampla/métodos , Humanos , Masculino , Proteínas de Membrana/genética , Proteínas do Tecido Nervoso/genética , Polimorfismo de Nucleotídeo Único
11.
Neurology ; 94(22): e2323-e2336, 2020 06 02.
Artigo em Inglês | MEDLINE | ID: mdl-32371448

RESUMO

OBJECTIVE: To identify which cortical regions are associated with direct electrical stimulation (DES)-induced alteration of breathing significant enough to impair pulse oximetry (SpO2). METHODS: Evolution of SpO2 after 1,352 DES was analyzed in 75 patients with refractory focal epilepsy who underwent stereo-EEG recordings. For each DES, we assessed the change in SpO2 from 30 seconds prior to DES onset to 120 seconds following the end of the DES. The primary outcome was occurrence of stimulation-induced transient hypoxemia as defined by decrease of SpO2 ≥5% within 60 seconds after stimulation onset as compared to pre-DES SpO2 or SpO2 nadir <90% during at least 5 seconds. Localization of the stimulated contacts was defined according to MarsAtlas brain parcellation and Freesurfer segmentation. RESULTS: A stimulation-induced transient hypoxemia was observed after 16 DES (1.2%) in 10 patients (13%), including 6 in whom SpO2 nadir was <90%. Among these 16 DES, 7 (44%) were localized within the perisylvian cortex. After correction for individual effects and the varying number of DES contributed by each person, significant decrease of SpO2 was significantly associated with the localization of DES (p = 0.019). CONCLUSION: Though rare, a significant decrease of SpO2 could be elicited by cortical direct electrical stimulation outside the temporo-limbic structures, most commonly after stimulation of the perisylvian cortex.


Assuntos
Mapeamento Encefálico/métodos , Córtex Cerebral/fisiopatologia , Eletroencefalografia/métodos , Hipóxia/fisiopatologia , Adulto , Córtex Cerebral/metabolismo , Estimulação Elétrica/métodos , Feminino , Humanos , Hipóxia/metabolismo , Masculino , Oximetria/métodos , Estudos Prospectivos , Adulto Jovem
12.
Toxicology ; 440: 152500, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32428529

RESUMO

Autism spectrum disorders (ASD) include neurodevelopmental disorders in which behavioral deficits can result from neuronal imbalance of excitation to inhibition (E/I) in the brain. Here we used RT-qPCR to screen for the expression of 99 genes associated with excitatory (glutamatergic) and inhibitory (GABAergic) neurotransmission in the cerebral cortex, hippocampus and cerebellum of rats in an established VPA model of ASD. The largest changes in the expression of glutamatergic genes were found in the cerebral cortex, where 12 genes including these encoding some of the subunits of the ionotropic glutamate receptors, were upregulated, while 2 genes were downregulated. The expression of genes encoding the presynaptic glutamatergic proteins vGluT1 and mGluR7 and PKA, involved in downstream glutamatergic signaling, was elevated more than 100-fold. Changes in GABAergic gene expression were found in the cortex, cerebellum and hippocampus; 3 genes were upregulated, and 3 were downregulated. In conclusion, these results revealed that, in the ASD model, several glutamatergic genes in the rat cerebral cortex were upregulated, which contrasts with small and balanced changes in the expression of GABAergic genes. The VPA rat model, useful in studying the molecular basis of ASD, may be suitable for testing experimental therapies in these disabilities.


Assuntos
Transtorno Autístico/induzido quimicamente , Transtorno Autístico/genética , Ácido Glutâmico/genética , Ácido Valproico , Ácido gama-Aminobutírico/genética , Animais , Cerebelo/efeitos dos fármacos , Cerebelo/metabolismo , Córtex Cerebral/efeitos dos fármacos , Córtex Cerebral/metabolismo , Feminino , GABAérgicos , Perfilação da Expressão Gênica , Hipocampo/efeitos dos fármacos , Hipocampo/metabolismo , Masculino , Gravidez , Efeitos Tardios da Exposição Pré-Natal , Ratos , Ratos Wistar , Receptores de Glutamato Metabotrópico/biossíntese , Receptores de Glutamato Metabotrópico/genética , Sinapses/efeitos dos fármacos , Sinapses/metabolismo , Proteína Vesicular 1 de Transporte de Glutamato/biossíntese , Proteína Vesicular 1 de Transporte de Glutamato/genética
13.
Proc Natl Acad Sci U S A ; 117(22): 12155-12163, 2020 06 02.
Artigo em Inglês | MEDLINE | ID: mdl-32430325

RESUMO

Microtubule polarity in axons and dendrites defines the direction of intracellular transport in neurons. Axons contain arrays of uniformly polarized microtubules with plus-ends facing the tips of the processes (plus-end-out), while dendrites contain microtubules with a minus-end-out orientation. It has been shown that cytoplasmic dynein, targeted to cortical actin, removes minus-end-out microtubules from axons. Here we have identified Spindly, a protein known for recruitment of dynein to kinetochores in mitosis, as a key factor required for dynein-dependent microtubule sorting in axons of Drosophila neurons. Depletion of Spindly affects polarity of axonal microtubules in vivo and in primary neuronal cultures. In addition to these defects, depletion of Spindly in neurons causes major collapse of axonal patterning in the third-instar larval brain as well as severe coordination impairment in adult flies. These defects can be fully rescued by full-length Spindly, but not by variants with mutations in its dynein-binding site. Biochemical analysis demonstrated that Spindly binds F-actin, suggesting that Spindly serves as a link between dynein and cortical actin in axons. Therefore, Spindly plays a critical role during neurodevelopment by mediating dynein-driven sorting of axonal microtubules.


Assuntos
Axônios/fisiologia , Proteínas de Ciclo Celular/metabolismo , Proteínas de Drosophila/metabolismo , Drosophila melanogaster/crescimento & desenvolvimento , Dineínas/metabolismo , Microtúbulos/fisiologia , Neurônios/fisiologia , Actinas/metabolismo , Animais , Transporte Biológico , Proteínas de Ciclo Celular/genética , Células Cultivadas , Córtex Cerebral/metabolismo , Dendritos/fisiologia , Proteínas de Drosophila/genética , Drosophila melanogaster/genética , Drosophila melanogaster/metabolismo , Cinetocoros/metabolismo , Proteínas Associadas aos Microtúbulos/metabolismo , Neurônios/citologia
14.
Proc Natl Acad Sci U S A ; 117(20): 11118-11125, 2020 05 19.
Artigo em Inglês | MEDLINE | ID: mdl-32358198

RESUMO

Cortical network functioning critically depends on finely tuned interactions to afford neuronal activity propagation over long distances while avoiding runaway excitation. This importance is highlighted by the pathological consequences and impaired performance resulting from aberrant network excitability in psychiatric and neurological diseases, such as epilepsy. Theory and experiment suggest that the control of activity propagation by network interactions can be adequately described by a branching process. This hypothesis is partially supported by strong evidence for balanced spatiotemporal dynamics observed in the cerebral cortex; however, evidence of a causal relationship between network interactions and cortex activity, as predicted by a branching process, is missing in humans. Here this cause-effect relationship is tested by monitoring cortex activity under systematic pharmacological reduction of cortical network interactions with antiepileptic drugs. This study reports that cortical activity cascades, presented by the propagating patterns of epileptic spikes, as well as temporal correlations decline precisely as predicted for a branching process. The results provide a missing link to the branching process theory of cortical network function with implications for understanding the foundations of cortical excitability and its monitoring in conditions like epilepsy.


Assuntos
Anticonvulsivantes/farmacologia , Córtex Cerebral/efeitos dos fármacos , Córtex Cerebral/metabolismo , Rede Nervosa/efeitos dos fármacos , Rede Nervosa/metabolismo , Eletrocorticografia , Epilepsia , Humanos , Redes Neurais de Computação , Neurônios/fisiologia
15.
J Vis Exp ; (159)2020 05 08.
Artigo em Inglês | MEDLINE | ID: mdl-32449730

RESUMO

Beginning from a limited pool of progenitors, the mammalian cerebral cortex forms highly organized functional neural circuits. However, the underlying cellular and molecular mechanisms regulating lineage transitions of neural stem cells (NSCs) and eventual production of neurons and glia in the developing neuroepithelium remains unclear. Methods to trace NSC division patterns and map the lineage of clonally related cells have advanced dramatically. However, many contemporary lineage tracing techniques suffer from the lack of cellular resolution of progeny cell fate, which is essential for deciphering progenitor cell division patterns. Presented is a protocol using mosaic analysis with double markers (MADM) to perform in vivo clonal analysis. MADM concomitantly manipulates individual progenitor cells and visualizes precise division patterns and lineage progression at unprecedented single cell resolution. MADM-based interchromosomal recombination events during the G2-X phase of mitosis, together with temporally inducible CreERT2, provide exact information on the birth dates of clones and their division patterns. Thus, MADM lineage tracing provides unprecedented qualitative and quantitative optical readouts of the proliferation mode of stem cell progenitors at the single cell level. MADM also allows for examination of the mechanisms and functional requirements of candidate genes in NSC lineage progression. This method is unique in that comparative analysis of control and mutant subclones can be performed in the same tissue environment in vivo. Here, the protocol is described in detail, and experimental paradigms to employ MADM for clonal analysis and lineage tracing in the developing cerebral cortex are demonstrated. Importantly, this protocol can be adapted to perform MADM clonal analysis in any murine stem cell niche, as long as the CreERT2 driver is present.


Assuntos
Córtex Cerebral/metabolismo , Células-Tronco Neurais/metabolismo , Animais , Diferenciação Celular , Camundongos , Células-Tronco Neurais/citologia
16.
Proc Natl Acad Sci U S A ; 117(19): 10554-10564, 2020 05 12.
Artigo em Inglês | MEDLINE | ID: mdl-32312821

RESUMO

A unique combination of transcription factor expression and projection neuron identity demarcates each layer of the cerebral cortex. During mouse and human cortical development, the transcription factor CTIP2 specifies neurons that project subcerebrally, while SATB2 specifies neuronal projections via the corpus callosum, a large axon tract connecting the two neocortical hemispheres that emerged exclusively in eutherian mammals. Marsupials comprise the sister taxon of eutherians but do not have a corpus callosum; their intercortical commissural neurons instead project via the anterior commissure, similar to egg-laying monotreme mammals. It remains unknown whether divergent transcriptional networks underlie these cortical wiring differences. Here, we combine birth-dating analysis, retrograde tracing, gene overexpression and knockdown, and axonal quantification to compare the functions of CTIP2 and SATB2 in neocortical development, between the eutherian mouse and the marsupial fat-tailed dunnart. We demonstrate a striking degree of structural and functional homology, whereby CTIP2 or SATB2 of either species is sufficient to promote a subcerebral or commissural fate, respectively. Remarkably, we reveal a substantial delay in the onset of developmental SATB2 expression in mice as compared to the equivalent stage in dunnarts, with premature SATB2 overexpression in mice to match that of dunnarts resulting in a marsupial-like projection fate via the anterior commissure. Our results suggest that small alterations in the timing of regulatory gene expression may underlie interspecies differences in neuronal projection fate specification.


Assuntos
Corpo Caloso/metabolismo , Eutérios/genética , Marsupiais/genética , Animais , Axônios/metabolismo , Evolução Biológica , Encéfalo/metabolismo , Córtex Cerebral/metabolismo , Corpo Caloso/fisiologia , Proteínas de Ligação a DNA/metabolismo , Evolução Molecular , Regulação da Expressão Gênica no Desenvolvimento/genética , Redes Reguladoras de Genes/genética , Humanos , Mamíferos/genética , Proteínas de Ligação à Região de Interação com a Matriz/genética , Proteínas de Ligação à Região de Interação com a Matriz/metabolismo , Camundongos , Vias Neurais/fisiologia , Neurônios/metabolismo , Proteínas Repressoras/genética , Proteínas Repressoras/metabolismo , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Proteínas Supressoras de Tumor/genética , Proteínas Supressoras de Tumor/metabolismo
17.
Neurology ; 94(19): e2026-e2036, 2020 05 12.
Artigo em Inglês | MEDLINE | ID: mdl-32291295

RESUMO

OBJECTIVE: To study the macrostructural and microstructural MRI correlates of brain astrocytosis, measured with 11C-deuterium-L-deprenyl (11C-DED)-PET, in familial autosomal-dominant Alzheimer disease (ADAD). METHODS: The total sample (n = 31) comprised ADAD mutation carriers (n = 10 presymptomatic, 39.2 ± 10.6 years old; n = 3 symptomatic, 55.5 ± 2.0 years old) and noncarriers (n = 18, 44.0 ± 13.7 years old) belonging to families with mutations in either the presenilin-1 or amyloid precursor protein genes. All participants underwent structural and diffusion MRI and neuropsychological assessment, and 20 participants (6 presymptomatic and 3 symptomatic mutation carriers and 11 noncarriers) also underwent 11C-DED-PET. RESULTS: Vertex-wise interaction analyses revealed a differential relationship between carriers and noncarriers in the association between 11C-DED binding and estimated years to onset (EYO) and between cortical mean diffusivity (MD) and EYO. These differences were due to higher 11C-DED binding in presymptomatic carriers, with lower binding in symptomatic carriers compared to noncarriers, and to lower cortical MD in presymptomatic carriers, with higher MD in symptomatic carriers compared to noncarriers. Using a vertex-wise local correlation approach, 11C-DED binding was negatively correlated with cortical MD and positively correlated with cortical thickness. CONCLUSIONS: Our proof-of-concept study is the first to show that microstructural and macrostructural changes can reflect underlying neuroinflammatory mechanisms in early stages of Alzheimer disease (AD). The findings support a role for neuroinflammation in AD pathogenesis, with potential implications for the correct interpretation of neuroimaging biomarkers as surrogate endpoints in clinical trials.


Assuntos
Doença de Alzheimer/metabolismo , Doença de Alzheimer/patologia , Córtex Cerebral/metabolismo , Córtex Cerebral/patologia , Adulto , Precursor de Proteína beta-Amiloide/genética , Encéfalo/patologia , Radioisótopos de Carbono/metabolismo , Deutério/metabolismo , Feminino , Heterozigoto , Humanos , Imagem por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Mutação , Neuroimagem , Testes Neuropsicológicos , Tomografia por Emissão de Pósitrons , Presenilina-1/genética , Sintomas Prodrômicos , Selegilina/metabolismo
18.
Nat Commun ; 11(1): 1631, 2020 04 02.
Artigo em Inglês | MEDLINE | ID: mdl-32242005

RESUMO

In the developing cortex, postmigratory neurons accumulate in the cortical plate (CP) to properly differentiate consolidating subtype identities. Microglia, despite their extensive surveying activity, temporarily disappear from the midembryonic CP. However, the mechanism and significance of this absence are unknown. Here, we show that microglia bidirectionally migrate via attraction by CXCL12 released from the meninges and subventricular zone and thereby exit the midembryonic CP. Upon nonphysiological excessive exposure to microglia in vivo or in vitro, young postmigratory and in vitro-grown CP neurons showed abnormal differentiation with disturbed expression of the subtype-associated transcription factors and genes implicated in functional neuronal maturation. Notably, this effect is primarily attributed to interleukin 6 and type I interferon secreted by microglia. These results suggest that "sanctuarization" from microglia in the midembryonic CP is required for neurons to appropriately fine-tune the expression of molecules needed for proper differentiation, thus securing the establishment of functional cortical circuit.


Assuntos
Córtex Cerebral/embriologia , Microglia/metabolismo , Neurogênese , Neurônios/citologia , Animais , Movimento Celular , Córtex Cerebral/metabolismo , Quimiocina CXCL12/metabolismo , Interferon Tipo I/metabolismo , Interleucina-6/metabolismo , Camundongos , Neurônios/metabolismo
19.
PLoS One ; 15(4): e0231978, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32315348

RESUMO

Ischemic strokes result in the death of brain tissue and a wave of downstream effects, often leading to lifelong disabilities or death. However, the underlying mechanisms of ischemic damage and repair systems remain largely unknown. In order to better understand these mechanisms, TMT-isobaric mass tagging and mass spectrometry were conducted on brain cortex extracts from mice subjected to one hour of middle cerebral artery occlusion (MCAO) and after one hour of reperfusion. In total, 2,690 proteins were identified and quantified, out of which 65% of the top 5% of up- and down-regulated proteins were found to be significant (p < 0.05). Network-based gene ontology analysis was then utilized to cluster all identified proteins by protein functional groups and cellular roles. Although three different cellular functions were identified-organelle outer membrane proteins, cytosolic ribosome proteins, and spliceosome complex proteins-several functional domains were found to be common. Of these, organelle outer membrane proteins were downregulated whereas cytosolic ribosome and spliceosome complex proteins were upregulated, indicating that major molecular events post-stroke were translation-associated and subsequent signaling pathways (e.g., poly (ADP-ribose) (PAR) dependent cell death). By approaching stroke analyses via TMT-isobaric mass tagging, the work herein presents a grand scope of protein-based molecular mechanisms involved with ischemic stroke recovery.


Assuntos
Córtex Cerebral/metabolismo , Espectrometria de Massas/métodos , Proteoma/metabolismo , Acidente Vascular Cerebral/patologia , Animais , Modelos Animais de Doenças , Regulação para Baixo , Ontologia Genética , Infarto da Artéria Cerebral Média/complicações , Masculino , Proteínas de Membrana/metabolismo , Camundongos , Proteoma/análise , Traumatismo por Reperfusão/metabolismo , Traumatismo por Reperfusão/patologia , Proteínas Ribossômicas/metabolismo , Transdução de Sinais/genética , Acidente Vascular Cerebral/etiologia , Acidente Vascular Cerebral/metabolismo , Regulação para Cima
20.
Neuron ; 107(1): 82-94.e6, 2020 07 08.
Artigo em Inglês | MEDLINE | ID: mdl-32330411

RESUMO

Patients lacking PYCR2, a mitochondrial enzyme that synthesizes proline, display postnatal degenerative microcephaly with hypomyelination. Here we report the crystal structure of the PYCR2 apo-enzyme and show that a novel germline p.Gly249Val mutation lies at the dimer interface and lowers its enzymatic activity. We find that knocking out Pycr2 in mice phenocopies the human disorder and depletes PYCR1 levels in neural lineages. In situ quantification of neurotransmitters in the brains of PYCR2 mutant mice and patients revealed a signature of encephalopathy driven by excessive cerebral glycine. Mechanistically, we demonstrate that loss of PYCR2 upregulates SHMT2, which is responsible for glycine synthesis. This hyperglycemia could be partially reversed by SHMT2 knockdown, which rescued the axonal beading and neurite lengths of cultured Pycr2 knockout neurons. Our findings identify the glycine metabolic pathway as a possible intervention point to alleviate the neurological symptoms of PYCR2-mutant patients.


Assuntos
Córtex Cerebral/metabolismo , Glicina Hidroximetiltransferase/metabolismo , Glicina/metabolismo , Doenças Desmielinizantes Hereditárias do Sistema Nervoso Central/patologia , Pirrolina Carboxilato Redutases/genética , Adolescente , Animais , Córtex Cerebral/patologia , Pré-Escolar , Feminino , Doenças Desmielinizantes Hereditárias do Sistema Nervoso Central/genética , Doenças Desmielinizantes Hereditárias do Sistema Nervoso Central/metabolismo , Humanos , Lactente , Masculino , Camundongos , Camundongos Knockout , Degeneração Neural/genética , Degeneração Neural/metabolismo , Degeneração Neural/patologia , Linhagem , Pirrolina Carboxilato Redutases/deficiência
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