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1.
Phys Rev Lett ; 125(12): 128102, 2020 Sep 18.
Artigo em Inglês | MEDLINE | ID: mdl-33016724

RESUMO

Neurodegenerative diseases, such as Alzheimer's or Parkinson's disease, show characteristic degradation of structural brain networks. This degradation eventually leads to changes in the network dynamics and degradation of cognitive functions. Here, we model the progression in terms of coupled physical processes: The accumulation of toxic proteins, given by a nonlinear reaction-diffusion transport process, yields an evolving brain connectome characterized by weighted edges on which a neuronal-mass model evolves. The progression of the brain functions can be tested by simulating the resting-state activity on the evolving brain network. We show that while the evolution of edge weights plays a minor role in the overall progression of the disease, dynamic biomarkers predict a transition over a period of 10 years associated with strong cognitive decline.


Assuntos
Demência/patologia , Modelos Neurológicos , Doenças Neurodegenerativas/patologia , Animais , Relógios Biológicos , Encéfalo/patologia , Encéfalo/fisiopatologia , Morte Celular/fisiologia , Disfunção Cognitiva/patologia , Disfunção Cognitiva/fisiopatologia , Conectoma/métodos , Demência/fisiopatologia , Humanos , Camundongos , Doenças Neurodegenerativas/fisiopatologia , Neurônios/patologia
2.
Nat Commun ; 11(1): 4966, 2020 10 02.
Artigo em Inglês | MEDLINE | ID: mdl-33009404

RESUMO

Temporal lobe epilepsy (TLE) is the most common type of drug-resistant epilepsy in adults, with an unknown etiology. A hallmark of TLE is the characteristic loss of layer 3 neurons in the medial entorhinal area (MEA) that underlies seizure development. One approach to intervention is preventing loss of these neurons through better understanding of underlying pathophysiological mechanisms. Here, we show that both neurons and glia together give rise to the pathology that is mitigated by the amino acid D-serine whose levels are potentially diminished under epileptic conditions. Focal administration of D-serine to the MEA attenuates neuronal loss in this region thereby preventing epileptogenesis in an animal model of TLE. Additionally, treatment with D-serine reduces astrocyte counts in the MEA, alters their reactive status, and attenuates proliferation and/or infiltration of microglia to the region thereby curtailing the deleterious consequences of neuroinflammation. Given the paucity of compounds that reduce hyperexcitability and neuron loss, have anti-inflammatory properties, and are well tolerated by the brain, D-serine, an endogenous amino acid, offers new hope as a therapeutic agent for refractory TLE.


Assuntos
Epilepsia do Lobo Temporal/tratamento farmacológico , Epilepsia do Lobo Temporal/patologia , Serina/uso terapêutico , Animais , Astrócitos/efeitos dos fármacos , Astrócitos/patologia , Comportamento Animal , Encéfalo/patologia , Córtex Entorrinal/efeitos dos fármacos , Córtex Entorrinal/patologia , Gliose/patologia , Inflamação/patologia , Microglia/efeitos dos fármacos , Microglia/patologia , Neurônios/efeitos dos fármacos , Neurônios/patologia , Ratos Sprague-Dawley , Serina/administração & dosagem , Serina/farmacologia
3.
Mol Neurobiol ; 57(12): 5263-5275, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32869183

RESUMO

Similar to its predecessors, coronavirus disease 2019 (COVID-19) exhibits neurotrophic properties, which lead to progression of neurologic sequelae. Besides direct viral invasion to the central nervous system (CNS), indirect CNS involvement through viral-mediated immune response is plausible. Aberrant immune pathways such as extreme release of cytokines (cytokine storm), autoimmunity mediated by cross-reactivity between CNS components and viral particles, and microglial activation propagate CNS damage in these patients. Here, we review the currently available evidence to discuss the plausible immunologic pathways that may contribute to the development of COVID-19 neurological complications, namely Alzheimer's disease, Parkinson's disease, stroke, multiple sclerosis, Guillain-Barre syndrome, seizure, and brainstem involvement.


Assuntos
Betacoronavirus , Infecções por Coronavirus/complicações , Doenças do Sistema Nervoso/etiologia , Pandemias , Pneumonia Viral/complicações , Animais , Betacoronavirus/imunologia , Betacoronavirus/patogenicidade , Tronco Encefálico/fisiopatologia , Tronco Encefálico/virologia , Infecções por Coronavirus/epidemiologia , Infecções por Coronavirus/imunologia , Síndrome da Liberação de Citocina/etiologia , Síndrome da Liberação de Citocina/imunologia , Efeito Citopatogênico Viral , Surtos de Doenças , Síndrome de Guillain-Barré/etiologia , Síndrome de Guillain-Barré/imunologia , Humanos , Camundongos , Esclerose Múltipla/etiologia , Esclerose Múltipla/imunologia , Proteínas do Tecido Nervoso/fisiologia , Doenças do Sistema Nervoso/imunologia , Doenças Neurodegenerativas/etiologia , Doenças Neurodegenerativas/imunologia , Neuroglia/patologia , Neuroglia/virologia , Neurônios/patologia , Neurônios/virologia , Peptidil Dipeptidase A/fisiologia , Pneumonia Viral/imunologia , Receptores Virais/fisiologia , Insuficiência Respiratória/etiologia , Insuficiência Respiratória/fisiopatologia , Convulsões/etiologia , Convulsões/imunologia , Síndrome Respiratória Aguda Grave/complicações , Síndrome Respiratória Aguda Grave/epidemiologia , Acidente Vascular Cerebral/etiologia , Acidente Vascular Cerebral/imunologia
4.
Mem Inst Oswaldo Cruz ; 115: e200007, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32935749

RESUMO

BACKGROUND: Behavioral and neurochemical alterations associated with toxoplasmosis may be influenced by the persistence of tissue cysts and activation of an immune response in the brain of Toxoplasma gondii-infected hosts. The cerebral extracellular matrix is organised as perineuronal nets (PNNs) that are both released and ensheath by some neurons and glial cells. There is evidences to suggest that PNNs impairment is a pathophysiological mechanism associated with neuropsychiatric conditions. However, there is a lack of information regarding the impact of parasitic infections on the PNNs integrity and how this could affect the host's behavior. OBJECTIVES: In this context, we aimed to analyse the impact of T. gondii infection on cyst burden, PNNs integrity, and possible effects in the locomotor activity of chronically infected mice. METHODS: We infected mice with T. gondii ME-49 strain. After thirty days, we assessed locomotor performance of animals using the open field test, followed by evaluation of cysts burden and PNNs integrity in four brain regions (primary and secondary motor cortices, prefrontal and somesthetic cortex) to assess the PNNs integrity using Wisteria floribunda agglutinin (WFA) labeling by immunohistochemical analyses. FINDINGS AND MAIN CONCLUSIONS: Our findings revealed a random distribution of cysts in the brain, the disruption of PNNs surrounding neurons in four areas of the cerebral cortex and hyperlocomotor behavior in T. gondii-infected mice. These results can contribute to elucidate the link toxoplasmosis with the establishment of neuroinflammatory response in neuropsychiatric disorders and to raise a discussion about the mechanisms related to changes in brain connectivity, with possible behavioral repercussions during chronic T. gondii infection.


Assuntos
Cerebelo/metabolismo , Matriz Extracelular/metabolismo , Neurônios Motores/citologia , Neurônios/patologia , Toxoplasmose Animal , Toxoplasmose/patologia , Animais , Cerebelo/citologia , Modelos Animais de Doenças , Camundongos , Neurônios Motores/metabolismo , Neurônios/metabolismo , Toxoplasma , Toxoplasmose/metabolismo
5.
PLoS Biol ; 18(8): e3000820, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32866173

RESUMO

Mutations in the gene encoding the microtubule-severing protein spastin (spastic paraplegia 4 [SPG4]) cause hereditary spastic paraplegia (HSP), associated with neurodegeneration, spasticity, and motor impairment. Complicated forms (complicated HSP [cHSP]) further include cognitive deficits and dementia; however, the etiology and dysfunctional mechanisms of cHSP have remained unknown. Here, we report specific working and associative memory deficits upon spastin depletion in mice. Loss of spastin-mediated severing leads to reduced synapse numbers, accompanied by lower miniature excitatory postsynaptic current (mEPSC) frequencies. At the subcellular level, mutant neurons are characterized by longer microtubules with increased tubulin polyglutamylation levels. Notably, these conditions reduce kinesin-microtubule binding, impair the processivity of kinesin family protein (KIF) 5, and reduce the delivery of presynaptic vesicles and postsynaptic α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors. Rescue experiments confirm the specificity of these results by showing that wild-type spastin, but not the severing-deficient and disease-associated K388R mutant, normalizes the effects at the synaptic, microtubule, and transport levels. In addition, short hairpin RNA (shRNA)-mediated reduction of tubulin polyglutamylation on spastin knockout background normalizes KIF5 transport deficits and attenuates the loss of excitatory synapses. Our data provide a mechanism that connects spastin dysfunction with the regulation of kinesin-mediated cargo transport, synapse integrity, and cognition.


Assuntos
Ácido Glutâmico/metabolismo , Cinesina/metabolismo , Transtornos da Memória/metabolismo , Transtornos da Memória/fisiopatologia , Memória de Curto Prazo , Neurônios/metabolismo , Espastina/deficiência , Tubulina (Proteína)/metabolismo , Potenciais de Ação , Animais , Membrana Celular/metabolismo , Espinhas Dendríticas/metabolismo , Espinhas Dendríticas/ultraestrutura , Potenciais Pós-Sinápticos Excitadores , Hipocampo/patologia , Hipocampo/fisiopatologia , Camundongos Knockout , Microtúbulos/metabolismo , Microtúbulos/ultraestrutura , Atividade Motora , Neurônios/patologia , Neurônios/ultraestrutura , Transporte Proteico , Espastina/metabolismo , Sinapses/metabolismo , Sinapses/ultraestrutura , Vesículas Sinápticas/metabolismo
6.
J Neurovirol ; 26(5): 631-641, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-32876900

RESUMO

A subset of patients with coronavirus 2 disease (COVID-19) experience neurological complications. These complications include loss of sense of taste and smell, stroke, delirium, and neuromuscular signs and symptoms. The etiological agent of COVID-19 is SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2), an RNA virus with a glycoprotein-studded viral envelope that uses ACE2 (angiotensin-converting enzyme 2) as a functional receptor for infecting the host cells. Thus, the interaction of the envelope spike proteins with ACE2 on host cells determines the tropism and virulence of SARS-CoV-2. Loss of sense of taste and smell is an initial symptom of COVID-19 because the virus enters the nasal and oral cavities first and the epithelial cells are the receptors for these senses. Stroke in COVID-19 patients is likely a consequence of coagulopathy and injury to cerebral vascular endothelial cells that cause thrombo-embolism and stroke. Delirium and encephalopathy in acute and post COVID-19 patients are likely multifactorial and secondary to hypoxia, metabolic abnormalities, and immunological abnormalities. Thus far, there is no clear evidence that coronaviruses cause inflammatory neuromuscular diseases via direct invasion of peripheral nerves or muscles or via molecular mimicry. It appears that most of neurologic complications in COVID-19 patients are indirect and as a result of a bystander injury to neurons.


Assuntos
Betacoronavirus/patogenicidade , Encefalopatias/complicações , Infecções por Coronavirus/complicações , Transtornos do Olfato/complicações , Pneumonia Viral/complicações , Embolia Pulmonar/complicações , Acidente Vascular Cerebral/complicações , Encéfalo/irrigação sanguínea , Encéfalo/patologia , Encéfalo/virologia , Encefalopatias/imunologia , Encefalopatias/patologia , Encefalopatias/virologia , Efeito Espectador , Infecções por Coronavirus/imunologia , Infecções por Coronavirus/patologia , Infecções por Coronavirus/virologia , Células Epiteliais/patologia , Células Epiteliais/virologia , Regulação da Expressão Gênica , Interações Hospedeiro-Patógeno/genética , Interações Hospedeiro-Patógeno/imunologia , Humanos , Pulmão/irrigação sanguínea , Pulmão/patologia , Pulmão/virologia , Neurônios/patologia , Neurônios/virologia , Transtornos do Olfato/imunologia , Transtornos do Olfato/patologia , Transtornos do Olfato/virologia , Pandemias , Peptidil Dipeptidase A/genética , Peptidil Dipeptidase A/imunologia , Pneumonia Viral/imunologia , Pneumonia Viral/patologia , Pneumonia Viral/virologia , Embolia Pulmonar/imunologia , Embolia Pulmonar/patologia , Embolia Pulmonar/virologia , Transdução de Sinais/genética , Transdução de Sinais/imunologia , Glicoproteína da Espícula de Coronavírus/genética , Glicoproteína da Espícula de Coronavírus/imunologia , Acidente Vascular Cerebral/imunologia , Acidente Vascular Cerebral/patologia , Acidente Vascular Cerebral/virologia
7.
Acta Neuropathol Commun ; 8(1): 147, 2020 08 26.
Artigo em Inglês | MEDLINE | ID: mdl-32847628

RESUMO

We document the neuropathologic findings of a 73-year old man who died from acute cerebellar hemorrhage in the context of relatively mild SARS-CoV2 infection. The patient developed sudden onset of headache, nausea, and vomiting, immediately followed by loss of consciousness on the day of admission. Emergency medical services found him severely hypoxemic at home, and the patient suffered a cardiac arrest during transport to the emergency department. The emergency team achieved return of spontaneous circulation after over 17 min of resuscitation. A chest radiograph revealed hazy bilateral opacities; and real-time-PCR for SARS-CoV-2 on the nasopharyngeal swab was positive. Computed tomography of the head showed a large right cerebellar hemorrhage, with tonsillar herniation and intraventricular hemorrhage. One day after presentation, he was transitioned to comfort care and died shortly after palliative extubation. Autopsy performed 3 h after death showed cerebellar hemorrhage and acute infarcts in the dorsal pons and medulla. Remarkably, there were microglial nodules and neuronophagia bilaterally in the inferior olives and multifocally in the cerebellar dentate nuclei. This constellation of findings has not been reported thus far in the context of SARS-CoV-2 infection.


Assuntos
Infartos do Tronco Encefálico/patologia , Doenças Cerebelares/patologia , Infecções por Coronavirus/patologia , Hemorragias Intracranianas/patologia , Microglia/patologia , Neurônios/patologia , Fagocitose , Pneumonia Viral/patologia , Idoso , Betacoronavirus , Infartos do Tronco Encefálico/complicações , Infartos do Tronco Encefálico/diagnóstico por imagem , Doenças Cerebelares/complicações , Doenças Cerebelares/diagnóstico por imagem , Núcleos Cerebelares/patologia , Infecções por Coronavirus/complicações , Infecções por Coronavirus/diagnóstico , Cefaleia/etiologia , Parada Cardíaca/etiologia , Humanos , Hipóxia/etiologia , Hemorragias Intracranianas/complicações , Hemorragias Intracranianas/diagnóstico por imagem , Masculino , Bulbo/diagnóstico por imagem , Bulbo/patologia , Núcleo Olivar/patologia , Pandemias , Pneumonia Viral/complicações , Pneumonia Viral/diagnóstico , Tegmento Pontino/diagnóstico por imagem , Tegmento Pontino/patologia , Tomografia Computadorizada por Raios X
8.
J Pharmacol Sci ; 144(2): 76-82, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32736867

RESUMO

Astrocytes, comprising the primary glial-cell type, are involved in the formation and maturation of synapses, and thus contribute to sustainable synaptic transmission between neurons. Given that the animals in higher phylogenetic tree have brains with a higher density of glial cells with respect to neurons, there is a possibility that the relative astrocytic density directly influences synaptic transmission. However, the notion has not been tested thoroughly. Here we addressed it, by using a primary culture preparation where single hippocampal neurons are surrounded by a variable but a countable number of cortical astrocytes in dot-patterned microislands, and recording synaptic transmission by patch-clamp electrophysiology. Neurons with a higher astrocytic density showed a higher amplitude of the evoked excitatory postsynaptic current than that of neurons with a lower astrocytic density. The size of the readily releasable pool of synaptic vesicles per neuron was significantly larger. The frequency of spontaneous synaptic transmission was higher, but the amplitude was unchanged. The number of morphologically identified glutamatergic synapses was comparable, but the percentage of functional ones was increased, indicating a lower ratio of presynaptically silent synapses. Taken together, the higher astrocytic density enhanced excitatory synaptic transmission by increasing the fraction of functional synapses through presynaptic un-silencing.


Assuntos
Astrócitos/fisiologia , Encéfalo/citologia , Neurônios/fisiologia , Sinapses/fisiologia , Transmissão Sináptica , Animais , Astrócitos/patologia , Células Cultivadas , Potenciais Pós-Sinápticos Excitadores , Feminino , Camundongos Endogâmicos ICR , Neurônios/patologia , Filogenia , Gravidez
9.
PLoS Biol ; 18(8): e3000851, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32822389

RESUMO

High levels of the amyloid-beta (Aß) peptide have been shown to disrupt neuronal function and induce hyperexcitability, but it is unclear what effects Aß-associated hyperexcitability may have on tauopathy pathogenesis or propagation in vivo. Using a novel transgenic mouse line to model the impact of human APP (hAPP)/Aß accumulation on tauopathy in the entorhinal cortex-hippocampal (EC-HIPP) network, we demonstrate that hAPP overexpression aggravates EC-Tau aggregation and accelerates pathological tau spread into the hippocampus. In vivo recordings revealed a strong role for hAPP/Aß, but not tau, in the emergence of EC neuronal hyperactivity and impaired theta rhythmicity. Chronic chemogenetic attenuation of EC neuronal hyperactivity led to reduced hAPP/Aß accumulation and reduced pathological tau spread into downstream hippocampus. These data strongly support the hypothesis that in Alzheimer's disease (AD), Aß-associated hyperactivity accelerates the progression of pathological tau along vulnerable neuronal circuits, and demonstrates the utility of chronic, neuromodulatory approaches in ameliorating AD pathology in vivo.


Assuntos
Doença de Alzheimer/genética , Precursor de Proteína beta-Amiloide/genética , Córtex Entorrinal/metabolismo , Tauopatias/genética , Proteínas tau/genética , Potenciais de Ação/fisiologia , Doença de Alzheimer/metabolismo , Doença de Alzheimer/patologia , Doença de Alzheimer/terapia , Precursor de Proteína beta-Amiloide/metabolismo , Animais , Proteína Quinase Tipo 2 Dependente de Cálcio-Calmodulina/genética , Proteína Quinase Tipo 2 Dependente de Cálcio-Calmodulina/metabolismo , Dependovirus/genética , Dependovirus/metabolismo , Modelos Animais de Doenças , Eletrodos Implantados , Córtex Entorrinal/patologia , Feminino , Regulação da Expressão Gênica , Vetores Genéticos/química , Vetores Genéticos/metabolismo , Hipocampo/metabolismo , Hipocampo/patologia , Humanos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Neurônios/metabolismo , Neurônios/patologia , Agregados Proteicos , Técnicas Estereotáxicas , Tauopatias/metabolismo , Tauopatias/patologia , Tauopatias/terapia , Ritmo Teta/fisiologia , Transdução Genética , Transgenes , Proteínas tau/metabolismo
10.
Nat Commun ; 11(1): 3358, 2020 07 03.
Artigo em Inglês | MEDLINE | ID: mdl-32620757

RESUMO

Neurodevelopmental disorders have a heritable component and are associated with region specific alterations in brain anatomy. However, it is unclear how genetic risks for neurodevelopmental disorders are translated into spatially patterned brain vulnerabilities. Here, we integrated cortical neuroimaging data from patients with neurodevelopmental disorders caused by genomic copy number variations (CNVs) and gene expression data from healthy subjects. For each of the six investigated disorders, we show that spatial patterns of cortical anatomy changes in youth are correlated with cortical spatial expression of CNV genes in neurotypical adults. By transforming normative bulk-tissue cortical expression data into cell-type expression maps, we link anatomical change maps in each analysed disorder to specific cell classes as well as the CNV-region genes they express. Our findings reveal organizing principles that regulate the mapping of genetic risks onto regional brain changes in neurogenetic disorders. Our findings will enable screening for candidate molecular mechanisms from readily available neuroimaging data.


Assuntos
Córtex Cerebral/patologia , Variações do Número de Cópias de DNA , Predisposição Genética para Doença , Transtornos do Neurodesenvolvimento/genética , Adolescente , Adulto , Mapeamento Encefálico , Córtex Cerebral/citologia , Córtex Cerebral/diagnóstico por imagem , Córtex Cerebral/crescimento & desenvolvimento , Criança , Estudos de Coortes , Feminino , Perfilação da Expressão Gênica , Genoma Humano , Humanos , Imagem por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Transtornos do Neurodesenvolvimento/diagnóstico , Transtornos do Neurodesenvolvimento/patologia , Neuroimagem , Neurônios/metabolismo , Neurônios/patologia , Oligodendroglia/metabolismo , Oligodendroglia/patologia , Análise Espacial , Adulto Jovem
11.
Chem Biol Interact ; 328: 109144, 2020 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-32653415

RESUMO

The debilitating nature of cognitive impairment in epilepsy and the potential of some traditional antiepileptics to further deteriorate cognitive function are areas of growing concern. Glucagon-like peptide-1 (GLP-1) deficiency has been linked to reduced seizure threshold as well as cognitive dysfunction. Here, we tested whether sitagliptin (SITA), by virtue of its neuroprotective properties, could alleviate both epilepsy and associated cognitive dysfunction in a rat model of kindling epilepsy. Chemical kindling was induced by subconvulsive doses of pentylenetetrazol (PTZ) (30 mg/kg; i.p). SITA (50 mg/kg; p.o) was administered 1 h before PTZ injections. SITA conceivably attenuated PTZ hippocampal histological insult, preserved neuronal integrity and amended neurotransmitter perturbations in rat hippocampi paralleled with enhanced hippocampal GLP-1 levels as well as the downstream cAMP content and protein kinase A (PKA) activity. Moreover, SITA improved cognitive functioning of rats in the Morris water maze which was coupled with hampered hippocampal p(Ser404)-tau and ß-amyloid proteins. SITA replenished p(Ser9)-glycogen synthase kinase-3ß (GSK-3ß). It also opposed the boosted matrix metalloproteinase-9 (MMP-9), brain-derived neurotrophic factor (BDNF), and insulin-like growth factor-1 (IGF-1) levels associated with PTZ administration along with mitigation of both ß-secretase-1 (BACE1) immunoreactivity and receptor for advanced glycation end products (RAGE) protein level in rat hippocampi. In conclusion, SITA subdues epileptic and cognitive upshots of PTZ kindling in rats, which might correspond to the modulation of BACE1, amyloidogenic/RAGE axis as well as GSK-3ß/MMP-9/BDNF signaling cascade. SITA effects are probably mediated via boosting GLP-1 and subsequently enhancing GLP-1/GLP-1R signaling.


Assuntos
Secretases da Proteína Precursora do Amiloide/metabolismo , Amiloide/metabolismo , Ácido Aspártico Endopeptidases/metabolismo , Transtornos Cognitivos/induzido quimicamente , Transtornos Cognitivos/metabolismo , Excitação Neurológica/efeitos dos fármacos , Receptor para Produtos Finais de Glicação Avançada/metabolismo , Transdução de Sinais , Fosfato de Sitagliptina/farmacologia , Peptídeos beta-Amiloides/metabolismo , Animais , Biomarcadores/metabolismo , Fator Neurotrófico Derivado do Encéfalo/metabolismo , Transtornos Cognitivos/patologia , Peptídeo 1 Semelhante ao Glucagon/metabolismo , Glicogênio Sintase Quinase 3 beta/metabolismo , Hipocampo/efeitos dos fármacos , Hipocampo/patologia , Fator de Crescimento Insulin-Like I/metabolismo , Masculino , Metaloproteinase 9 da Matriz/metabolismo , Inibição Neural/efeitos dos fármacos , Neurônios/efeitos dos fármacos , Neurônios/metabolismo , Neurônios/patologia , Neurotransmissores/metabolismo , Pentilenotetrazol , Ratos Wistar , Convulsões/induzido quimicamente , Convulsões/metabolismo , Convulsões/patologia , Transdução de Sinais/efeitos dos fármacos , Memória Espacial/efeitos dos fármacos , Proteínas tau/metabolismo
12.
PLoS Genet ; 16(7): e1008901, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32645003

RESUMO

The RNA exosome is an evolutionarily-conserved ribonuclease complex critically important for precise processing and/or complete degradation of a variety of cellular RNAs. The recent discovery that mutations in genes encoding structural RNA exosome subunits cause tissue-specific diseases makes defining the role of this complex within specific tissues critically important. Mutations in the RNA exosome component 3 (EXOSC3) gene cause Pontocerebellar Hypoplasia Type 1b (PCH1b), an autosomal recessive neurologic disorder. The majority of disease-linked mutations are missense mutations that alter evolutionarily-conserved regions of EXOSC3. The tissue-specific defects caused by these amino acid changes in EXOSC3 are challenging to understand based on current models of RNA exosome function with only limited analysis of the complex in any multicellular model in vivo. The goal of this study is to provide insight into how mutations in EXOSC3 impact the function of the RNA exosome. To assess the tissue-specific roles and requirements for the Drosophila ortholog of EXOSC3 termed Rrp40, we utilized tissue-specific RNAi drivers. Depletion of Rrp40 in different tissues reveals a general requirement for Rrp40 in the development of many tissues including the brain, but also highlight an age-dependent requirement for Rrp40 in neurons. To assess the functional consequences of the specific amino acid substitutions in EXOSC3 that cause PCH1b, we used CRISPR/Cas9 gene editing technology to generate flies that model this RNA exosome-linked disease. These flies show reduced viability; however, the surviving animals exhibit a spectrum of behavioral and morphological phenotypes. RNA-seq analysis of these Drosophila Rrp40 mutants reveals increases in the steady-state levels of specific mRNAs and ncRNAs, some of which are central to neuronal function. In particular, Arc1 mRNA, which encodes a key regulator of synaptic plasticity, is increased in the Drosophila Rrp40 mutants. Taken together, this study defines a requirement for the RNA exosome in specific tissues/cell types and provides insight into how defects in RNA exosome function caused by specific amino acid substitutions that occur in PCH1b can contribute to neuronal dysfunction.


Assuntos
Doenças Cerebelares/genética , Proteínas do Citoesqueleto/genética , Drosophila melanogaster/genética , Complexo Multienzimático de Ribonucleases do Exossomo/genética , Proteínas do Tecido Nervoso/genética , Neurônios/metabolismo , Proteínas de Ligação a RNA/genética , Substituição de Aminoácidos/genética , Animais , Sistemas CRISPR-Cas/genética , Doenças Cerebelares/patologia , Cerebelo/metabolismo , Cerebelo/patologia , Modelos Animais de Doenças , Exossomos/genética , Humanos , Mutação/genética , Neurônios/patologia , RNA/genética
13.
PLoS Genet ; 16(7): e1008920, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32697780

RESUMO

Neurofibromatosis type 1 is a monogenetic disorder that predisposes individuals to tumor formation and cognitive and behavioral symptoms. The neuronal circuitry and developmental events underlying these neurological symptoms are unknown. To better understand how mutations of the underlying gene (NF1) drive behavioral alterations, we have examined grooming in the Drosophila neurofibromatosis 1 model. Mutations of the fly NF1 ortholog drive excessive grooming, and increased grooming was observed in adults when Nf1 was knocked down during development. Furthermore, intact Nf1 Ras GAP-related domain signaling was required to maintain normal grooming. The requirement for Nf1 was distributed across neuronal circuits, which were additive when targeted in parallel, rather than mapping to discrete microcircuits. Overall, these data suggest that broadly-distributed alterations in neuronal function during development, requiring intact Ras signaling, drive key Nf1-mediated behavioral alterations. Thus, global developmental alterations in brain circuits/systems function may contribute to behavioral phenotypes in neurofibromatosis type 1.


Assuntos
Proteínas de Drosophila/genética , Desenvolvimento Embrionário/genética , Proteínas do Tecido Nervoso/genética , Neurofibromatose 1/genética , Neurônios/metabolismo , Proteínas Ativadoras de ras GTPase/genética , Animais , Cognição/fisiologia , Modelos Animais de Doenças , Drosophila melanogaster/genética , Embrião não Mamífero , Técnicas de Silenciamento de Genes , Asseio Animal/fisiologia , Humanos , Mutação/genética , Neurofibromatose 1/patologia , Neurônios/patologia
14.
Toxicol Lett ; 332: 192-201, 2020 Oct 10.
Artigo em Inglês | MEDLINE | ID: mdl-32693020

RESUMO

Fenvalerate, a synthetic pyrethroid insecticide, is an environmental endocrine disruptor and neurodevelopmental toxicant. An early report found that pubertal exposure to high-dose fenvalerate impaired cognitive and behavioral development. Here, we aimed to further investigate the effect of pubertal exposure to low-dose fenvalerate on cognitive and behavioral development. Mice were orally administered with fenvalerate (0.2, 1.0 and 5.0 mg/kg) daily from postnatal day (PND) 28 to PND56. Learning and memory were assessed by Morris water maze. Anxiety-related activities were detected by open-field and elevated plus-maze. Increased anxiety activities were observed only in females exposed to fenvalerate. Spatial learning and memory were damaged only in females exposed to fenvalerate. Histopathology observed numerous scattered shrinking neurons and nuclear pyknosis in hippocampal CA1 region. Neuronal density was reduced in hippocampal CA1 region of fenvalerate-exposed mice. Mechanistically, hippocampal thyroid hormone receptor (TR)ß1 was down-regulated in a dose-dependent manner in females. In addition, TRα1 was declined only in females exposed to 5.0 mg/kg fenvalerate. Taken together, these suggests that pubertal exposure to low-dose fenvalerate impairs cognitive and behavioral development in a gender-dependent manner. Hippocampal TR signaling may be, at least partially, involved in fenvalerate-induced impairment of cognitive and behavioral development.


Assuntos
Transtornos Cognitivos/induzido quimicamente , Hipocampo/metabolismo , Inseticidas/toxicidade , Nitrilos/toxicidade , Piretrinas/toxicidade , Transdução de Sinais/efeitos dos fármacos , Hormônios Tireóideos , Animais , Ansiedade/induzido quimicamente , Ansiedade/psicologia , Peso Corporal/efeitos dos fármacos , Região CA1 Hipocampal/efeitos dos fármacos , Região CA1 Hipocampal/metabolismo , Transtornos Cognitivos/psicologia , Relação Dose-Resposta a Droga , Regulação para Baixo/efeitos dos fármacos , Ingestão de Alimentos/efeitos dos fármacos , Disruptores Endócrinos , Feminino , Hipocampo/efeitos dos fármacos , Masculino , Aprendizagem em Labirinto/efeitos dos fármacos , Camundongos , Camundongos Endogâmicos ICR , Neurônios/patologia , Receptores dos Hormônios Tireóideos/efeitos dos fármacos , Caracteres Sexuais
15.
Life Sci ; 258: 118099, 2020 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-32682917

RESUMO

Although emerging evidence has highlighted the heterogeneities of astrocytes under physiological versus pathological conditions, little is known regarding these processes in different brain regions during stress. Thus, the present study established a mouse model of chronic social defeat stress (CSDS) and isolated astrocytes from the medial prefrontal cortex (mPFC) and hippocampus. The results revealed dramatic A1-specific (neurotoxic phenotype) astrocytic responses, depressive-like behaviors, and significant inhibition of neuronal activities in both the mPFC and hippocampus according to electrophysiological data. Subsequently, astrocytes in the mPFC and hippocampus of CSDS mice were suppressed and this reversed the astrocytic responses and rescued depressive-like behaviors. Furthermore, when astrocytes were activated in the mPFC and hippocampus in healthy mice, there was a non-specific phenotypic activation of astrocytes in the absence of depressive-like behaviors. Next, microglia were depleted and the mice subsequently performed in the CSDS model; this reduced astrocyte responses and restored depressive-like behaviors. On the other hand, when microglia were depleted but astrocytes were activated in CSDS mice, this abolished the restoration of microglia depletion-induced depressive-like behaviors. Taken together, these results indicate that neuronal inhibition by astrocytes in the mPFC and hippocampus contributed to depressive-like behaviors mediated by activated microglia. This study provides evidence regarding the interaction of microglia and astrocytes during stress and how that relationship can trigger depressive-like behaviors.


Assuntos
Astrócitos/patologia , Comportamento Animal , Depressão/psicologia , Neurônios/patologia , Estresse Psicológico/patologia , Animais , Doença Crônica , Hipocampo/patologia , Locomoção , Masculino , Camundongos , Inibição Neural , Neuroglia/metabolismo , Córtex Pré-Frontal/patologia
16.
Nat Commun ; 11(1): 3354, 2020 07 03.
Artigo em Inglês | MEDLINE | ID: mdl-32620797

RESUMO

Expansion of an intronic (GGGGCC)n repeat region within the C9orf72 gene is a main cause of familial amyotrophic lateral sclerosis and frontotemporal dementia (c9ALS/FTD). A hallmark of c9ALS/FTD is the accumulation of misprocessed RNAs, which are often targets of cellular RNA surveillance. Here, we show that RNA decay mechanisms involving upstream frameshift 1 (UPF1), including nonsense-mediated decay (NMD), are inhibited in c9ALS/FTD brains and in cultured cells expressing either of two arginine-rich dipeptide repeats (R-DPRs), poly(GR) and poly(PR). Mechanistically, although R-DPRs cause the recruitment of UPF1 to stress granules, stress granule formation is independent of NMD inhibition. Instead, NMD inhibition is primarily a result from global translational repression caused by R-DPRs. Overexpression of UPF1, but none of its NMD-deficient mutants, enhanced the survival of neurons treated by R-DPRs, suggesting that R-DPRs cause neurotoxicity in part by inhibiting cellular RNA surveillance.


Assuntos
Esclerose Amiotrófica Lateral/genética , Proteína C9orf72/genética , Demência Frontotemporal/genética , Degradação do RNAm Mediada por Códon sem Sentido , RNA Helicases/metabolismo , Transativadores/metabolismo , Esclerose Amiotrófica Lateral/patologia , Animais , Linhagem Celular Tumoral , Sobrevivência Celular/genética , Expansão das Repetições de DNA , Conjuntos de Dados como Assunto , Embrião de Mamíferos , Feminino , Lobo Frontal/patologia , Demência Frontotemporal/patologia , Humanos , Íntrons/genética , Camundongos , Neurônios/metabolismo , Neurônios/patologia , Cultura Primária de Células , Biossíntese de Proteínas , RNA Mensageiro/metabolismo , RNA-Seq , Transativadores/genética
17.
PLoS One ; 15(7): e0236826, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32730314

RESUMO

Down syndrome (DS), is the most common cause of intellectual disability, and is characterized by defective neurogenesis during perinatal development. To identify metabolic aberrations in early neurogenesis, we profiled neurospheres derived from the embryonic brain of Ts1Cje, a mouse model of Down syndrome. High-throughput phenotypic microarray revealed a significant decrease in utilisation of 17 out of 367 substrates and significantly higher utilisation of 6 substrates in the Ts1Cje neurospheres compared to controls. Specifically, Ts1Cje neurospheres were less efficient in the utilisation of glucose-6-phosphate suggesting a dysregulation in the energy-producing pathway. T Cje neurospheres were significantly smaller in diameter than the controls. Subsequent preliminary study on supplementation with 6-phosphogluconic acid, an intermediate of glucose-6-phosphate metabolism, was able to rescue the Ts1Cje neurosphere size. This study confirmed the perturbed pentose phosphate pathway, contributing to defects observed in Ts1Cje neurospheres. We show for the first time that this comprehensive energetic assay platform facilitates the metabolic characterisation of Ts1Cje cells and confirmed their distinguishable metabolic profiles compared to the controls.


Assuntos
Encéfalo/patologia , Síndrome de Down/patologia , Neurogênese , Neurônios/metabolismo , Neurônios/patologia , Animais , Encéfalo/embriologia , Encéfalo/metabolismo , Síndrome de Down/metabolismo , Feminino , Camundongos , Camundongos Endogâmicos C57BL , Análise em Microsséries , Fenótipo
18.
Nat Commun ; 11(1): 3143, 2020 06 19.
Artigo em Inglês | MEDLINE | ID: mdl-32561719

RESUMO

Topoisomerase 3ß (Top3ß) is the only dual-activity topoisomerase in animals that can change topology for both DNA and RNA, and facilitate transcription on DNA and translation on mRNAs. Top3ß mutations have been linked to schizophrenia, autism, epilepsy, and cognitive impairment. Here we show that Top3ß knockout mice exhibit behavioural phenotypes related to psychiatric disorders and cognitive impairment. The mice also display impairments in hippocampal neurogenesis and synaptic plasticity. Notably, the brains of the mutant mice exhibit impaired global neuronal activity-dependent transcription in response to fear conditioning stress, and the affected genes include many with known neuronal functions. Our data suggest that Top3ß is essential for normal brain function, and that defective neuronal activity-dependent transcription may be a mechanism by which Top3ß deletion causes cognitive impairment and psychiatric disorders.


Assuntos
Disfunção Cognitiva/genética , DNA Topoisomerases Tipo I/genética , Transtornos Mentais/genética , Neurogênese/genética , Plasticidade Neuronal/genética , Animais , Técnicas de Observação do Comportamento , Comportamento Animal , Disfunção Cognitiva/diagnóstico , Disfunção Cognitiva/patologia , Modelos Animais de Doenças , Feminino , Hipocampo/citologia , Hipocampo/diagnóstico por imagem , Hipocampo/crescimento & desenvolvimento , Hipocampo/patologia , Humanos , Imagem por Ressonância Magnética , Masculino , Transtornos Mentais/diagnóstico , Transtornos Mentais/patologia , Camundongos , Camundongos Knockout , Neurônios/patologia , Técnicas Estereotáxicas , Potenciais Sinápticos/genética , Transcrição Genética/fisiologia
19.
PLoS One ; 15(6): e0234394, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32574176

RESUMO

In the BACHD mouse model of Huntington's disease (HD), deletion of the N17 domain of the Huntingtin gene (BACHDΔN17, Q97) has been reported to lead to nuclear accumulation of mHTT and exacerbation of motor deficits, neuroinflammation and striatal atrophy (Gu et al., 2015). Here we characterized the effect of N17 deletion on dorsolateral striatal medium spiny neurons (MSNs) in BACHDΔN17 (Q97) and BACWTΔN17 (Q31) mice by comparing them to MSNs in wildtype (WT) mice. Mice were characterized on a series of motor tasks and subsequently whole cell patch clamp recordings with simultaneous biocytin filling of MSNs in in vitro striatal slices from these mice were used to comprehensively assess their physiological and morphological features. Key findings include that: Q97 mice exhibit impaired gait and righting reflexes but normal tail suspension reflexes and normal coats while Q31 mice do not differ from WT; intrinsic membrane and action potential properties are altered -but differentially so- in MSNs from Q97 and from Q31 mice; excitatory and inhibitory synaptic currents exhibit higher amplitudes in Q31 but not Q97 MSNs, while excitatory synaptic currents occur at lower frequency in Q97 than in WT and Q31 MSNs; there is a reduced total dendritic length in Q31 -but not Q97- MSNs compared to WT, while spine density and number did not differ in MSNs in the three groups. The findings that Q31 MSNs differed from Q97 and WT neurons with regard to some physiological features and structurally suggest a novel role of the N17 domain in the function of WT Htt. The motor phenotype seen in Q97 mice was less robust than that reported in an earlier study (Gu et al., 2015), and the alterations to MSN physiological properties were largely consistent with changes reported previously in a number of other mouse models of HD. Together this study indicates that N17 plays a role in the modulation of the properties of MSNs in both mHtt and WT-Htt mice, but does not markedly exacerbate HD-like pathogenesis in the BACHD model.


Assuntos
Proteína Huntingtina/genética , Doença de Huntington/genética , Potenciais de Ação , Animais , Corpo Estriado/patologia , Corpo Estriado/fisiopatologia , Dendritos/patologia , Modelos Animais de Doenças , Potenciais Pós-Sinápticos Excitadores , Feminino , Humanos , Proteína Huntingtina/química , Proteína Huntingtina/fisiologia , Doença de Huntington/patologia , Doença de Huntington/fisiopatologia , Coxeadura Animal/genética , Coxeadura Animal/fisiopatologia , Masculino , Camundongos , Camundongos Mutantes , Camundongos Transgênicos , Proteínas Mutantes/química , Proteínas Mutantes/genética , Proteínas Mutantes/fisiologia , Neurônios/patologia , Neurônios/fisiologia , Domínios Proteicos , Reflexo Anormal/genética , Reflexo Anormal/fisiologia , Deleção de Sequência
20.
Brain Tumor Pathol ; 37(3): 100-104, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32535663

RESUMO

A subset of central nervous system neuroblastomas (CNS NB), rare primary embryonal CNS tumors, has been encompassed in CNS NB with FOXR2 activation (CNS NB-FOXR2) and usually shows the primitive neuronal architecture and occasional neurocytic differentiation. Here, we report a rare case of 3-year-old female with uncommon morphology of CNS embryonal tumor with FOXR2 activation presenting bidirectional differentiation to neurocytic small primitive cells and astrocytic spindle cells both of which are positive for synaptophysin and GFAP. Ultrastructural study also showed that there were presynaptic structure and intermediate filament in the tumor cells, suggesting glioneuronal differentiation. This case indicates the possibility of CNS neuroblastic tumor to differentiate neuronal and glial lineages.


Assuntos
Neoplasias Encefálicas/genética , Neoplasias Encefálicas/patologia , Fatores de Transcrição Forkhead/genética , Neuroblastoma/genética , Neuroblastoma/patologia , Neuroglia/patologia , Neurônios/patologia , Ativação Transcricional , Neoplasias Encefálicas/diagnóstico por imagem , Pré-Escolar , Feminino , Humanos , Imagem por Ressonância Magnética , Neuroblastoma/diagnóstico por imagem , Tomografia Computadorizada por Raios X
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