RESUMO
Intranasal administration of total bovine brain gangliosides (6 mg/kg) to rats protected the CA1 hippocampal neurons from the death caused by two-vessel occlusion model (with hypotension) of forebrain ischemia/reperfusion injury. The immunohistochemical reaction of specific antibodies to marker proteins of activated microglia (Iba1) and astrocytes (GFAP) in hippocampal slices revealed the neuroprotective effect of exogenous gangliosides which can be mostly explained by their ability to suppress neuroinflammation and gliosis. The expression of neurotrophic factor BDNF in the CA1 region of hippocampus did not differ in sham-operated rats and animals exposed to ischemia/reperfusion. However, the administration of gangliosides increased the BDNF expression in both control and ischemic groups. The intranasal route of administration allows using lower concentrations of gangliosides preventing the death of hippocampal neurons.
Assuntos
Administração Intranasal , Fator Neurotrófico Derivado do Encéfalo , Região CA1 Hipocampal , Gangliosídeos , Neurônios , Fármacos Neuroprotetores , Traumatismo por Reperfusão , Animais , Traumatismo por Reperfusão/patologia , Traumatismo por Reperfusão/tratamento farmacológico , Traumatismo por Reperfusão/metabolismo , Gangliosídeos/farmacologia , Ratos , Masculino , Região CA1 Hipocampal/efeitos dos fármacos , Região CA1 Hipocampal/patologia , Região CA1 Hipocampal/metabolismo , Fator Neurotrófico Derivado do Encéfalo/metabolismo , Neurônios/efeitos dos fármacos , Neurônios/metabolismo , Neurônios/patologia , Fármacos Neuroprotetores/farmacologia , Fármacos Neuroprotetores/administração & dosagem , Ratos Wistar , Proteína Glial Fibrilar Ácida/metabolismo , Proteínas de Ligação ao Cálcio/metabolismo , Proteínas dos Microfilamentos/metabolismo , Isquemia Encefálica/tratamento farmacológico , Isquemia Encefálica/patologia , Isquemia Encefálica/metabolismo , Prosencéfalo/efeitos dos fármacos , Prosencéfalo/patologia , Prosencéfalo/metabolismo , Astrócitos/efeitos dos fármacos , Astrócitos/metabolismo , Astrócitos/patologia , Microglia/efeitos dos fármacos , Microglia/metabolismo , Microglia/patologia , Sobrevivência Celular/efeitos dos fármacos , Modelos Animais de DoençasRESUMO
The assembly of cortical circuits involves the generation and migration of interneurons from the ventral to the dorsal forebrain1-3, which has been challenging to study at inaccessible stages of late gestation and early postnatal human development4. Autism spectrum disorder and other neurodevelopmental disorders (NDDs) have been associated with abnormal cortical interneuron development5, but which of these NDD genes affect interneuron generation and migration, and how they mediate these effects remains unknown. We previously developed a platform to study interneuron development and migration in subpallial organoids and forebrain assembloids6. Here we integrate assembloids with CRISPR screening to investigate the involvement of 425 NDD genes in human interneuron development. The first screen aimed at interneuron generation revealed 13 candidate genes, including CSDE1 and SMAD4. We subsequently conducted an interneuron migration screen in more than 1,000 forebrain assembloids that identified 33 candidate genes, including cytoskeleton-related genes and the endoplasmic reticulum-related gene LNPK. We discovered that, during interneuron migration, the endoplasmic reticulum is displaced along the leading neuronal branch before nuclear translocation. LNPK deletion interfered with this endoplasmic reticulum displacement and resulted in abnormal migration. These results highlight the power of this CRISPR-assembloid platform to systematically map NDD genes onto human development and reveal disease mechanisms.
Assuntos
Sistemas CRISPR-Cas , Edição de Genes , Transtornos do Neurodesenvolvimento , Feminino , Humanos , Recém-Nascido , Gravidez , Movimento Celular/genética , Sistemas CRISPR-Cas/genética , Interneurônios/citologia , Interneurônios/metabolismo , Interneurônios/patologia , Transtornos do Neurodesenvolvimento/genética , Transtornos do Neurodesenvolvimento/patologia , Organoides/citologia , Organoides/embriologia , Organoides/crescimento & desenvolvimento , Organoides/metabolismo , Organoides/patologia , Retículo Endoplasmático/metabolismo , Prosencéfalo/citologia , Prosencéfalo/embriologia , Prosencéfalo/crescimento & desenvolvimento , Prosencéfalo/metabolismo , Prosencéfalo/patologia , Transporte Ativo do Núcleo CelularRESUMO
Multiple sclerosis (MS) is a central nervous system disease characterized by both degenerative and inflammatory processes. Various mediators are involved in the interplay of degeneration and innate immunity on one hand and peripheral adaptive immunity on the other hand. The secreted protein lipocalin 2 (LCN2) is an inflammatory modulator in a variety of pathologies. Although elevated intrathecal levels of LCN2 have been reported in MS patients, it's functional role is widely unknown. Here, we identified a subpopulation of astrocytes as a source of LCN2 in MS lesions and respective animal models. We investigated the functional role of LCN2 for both autoimmune and degenerative aspects in three MS mouse models including both wild type (WT) and Lcn2-/- mouse strains. While the experimental autoimmune encephalomyelitis (EAE) model reflects primary autoimmunity, the cuprizone model reflects selective oligodendrocyte loss and demyelination. In addition, we included a combinatory Cup/EAE model in which primary cytodegeneration is followed by inflammatory lesions within the forebrain. While in the EAE model, the disease outcome was comparable in between the two mouse strains, cuprizone intoxicated Lcn2-/- animals showed an increased loss of oligodendrocytes. In the Cup/EAE model, Lcn2-/- animals showed increased inflammation when compared to WT mice. Together, our results highlight LCN2 as a potentially protective molecule in MS lesion formation, which might be able to limit loss of oligodendrocytes immune-cell invasion. Despite these findings, it is not yet clear which glial cell phenotype (and to which extent) contributes to the observed neuroprotective effects, that is, microglia and/or astroglia or even endothelial cells in the brain.
Assuntos
Encefalomielite Autoimune Experimental , Lipocalina-2/metabolismo , Esclerose Múltipla , Animais , Cuprizona , Modelos Animais de Doenças , Encefalomielite Autoimune Experimental/metabolismo , Células Endoteliais/metabolismo , Lipocalina-2/genética , Camundongos , Camundongos Endogâmicos C57BL , Esclerose Múltipla/patologia , Oligodendroglia/metabolismo , Prosencéfalo/patologiaRESUMO
Progress in earlier detection and clinical management has increased life expectancy and quality of life in people with Down syndrome (DS). However, no drug has been approved to help individuals with DS live independently and fully. Although rat models could support more robust physiological, behavioral, and toxicology analysis than mouse models during preclinical validation, no DS rat model is available as a result of technical challenges. We developed a transchromosomic rat model of DS, TcHSA21rat, which contains a freely segregating, EGFP-inserted, human chromosome 21 (HSA21) with >93% of its protein-coding genes. RNA-seq of neonatal forebrains demonstrates that TcHSA21rat expresses HSA21 genes and has an imbalance in global gene expression. Using EGFP as a marker for trisomic cells, flow cytometry analyses of peripheral blood cells from 361 adult TcHSA21rat animals show that 81% of animals retain HSA21 in >80% of cells, the criterion for a "Down syndrome karyotype" in people. TcHSA21rat exhibits learning and memory deficits and shows increased anxiety and hyperactivity. TcHSA21rat recapitulates well-characterized DS brain morphology, including smaller brain volume and reduced cerebellar size. In addition, the rat model shows reduced cerebellar foliation, which is not observed in DS mouse models. Moreover, TcHSA21rat exhibits anomalies in craniofacial morphology, heart development, husbandry, and stature. TcHSA21rat is a robust DS animal model that can facilitate DS basic research and provide a unique tool for preclinical validation to accelerate DS drug development.
Assuntos
Ansiedade/genética , Cromossomos Humanos Par 21 , Síndrome de Down/genética , Efeito Fundador , Hipercinese/genética , Animais , Ansiedade/metabolismo , Ansiedade/patologia , Cerebelo/metabolismo , Cerebelo/patologia , Modelos Animais de Doenças , Síndrome de Down/metabolismo , Síndrome de Down/patologia , Feminino , Genes Reporter , Proteínas de Fluorescência Verde/genética , Proteínas de Fluorescência Verde/metabolismo , Humanos , Hipercinese/metabolismo , Hipercinese/patologia , Cariótipo , Aprendizagem , Masculino , Mutagênese Insercional , Tamanho do Órgão , Postura , Prosencéfalo/metabolismo , Prosencéfalo/patologia , Ratos , Ratos TransgênicosRESUMO
The present study has explored the hypothesis that neurokinin1 receptors (NK1Rs) in medial septum (MS) modulate nociception evoked on hind paw injection of formalin. Indeed, the NK1Rs in MS are localized on cholinergic neurons which have been implicated in nociception. In anaesthetized rat, microinjection of L-733,060, an antagonist at NK1Rs, into MS antagonized the suppression of CA1 population spike (PS) evoked on peripheral injection of formalin or on intraseptal microinjection of substance P (SP), an agonist at NK1Rs. The CA1 PS reflects the synaptic excitability of pyramidal cells in the region. Furthermore, microinjection of L-733,060 into MS, but not LS, attenuated formalin-induced theta activation in both anaesthetized and awake rat, where theta reflects an oscillatory information processing by hippocampal neurons. The effects of L-733,060 on microinjection into MS were nociceptive selective as the antagonist did not block septo-hippocampal response to direct MS stimulation by the cholinergic receptor agonist, carbachol, in anaesthetized animal or on exploration in awake animal. Interestingly, microinjection of L-733,060 into both MS and LS attenuated formalin-induced nociceptive flinches. Collectively, the foregoing novel findings highlight that transmission at NK1R provide an affective valence to septo-hippocampal information processing and that peptidergic transmission in the septum modulates nociceptive behaviours.
Assuntos
Formaldeído/toxicidade , Inflamação/tratamento farmacológico , Nociceptividade/efeitos dos fármacos , Dor/tratamento farmacológico , Piperidinas/farmacologia , Prosencéfalo/efeitos dos fármacos , Receptores da Neurocinina-1/química , Núcleos Septais/efeitos dos fármacos , Animais , Desinfetantes/toxicidade , Hipocampo/efeitos dos fármacos , Hipocampo/metabolismo , Hipocampo/patologia , Inflamação/induzido quimicamente , Inflamação/metabolismo , Inflamação/patologia , Masculino , Dor/induzido quimicamente , Dor/metabolismo , Dor/patologia , Prosencéfalo/metabolismo , Prosencéfalo/patologia , Ratos , Ratos Sprague-Dawley , Receptores da Neurocinina-1/metabolismo , Núcleos Septais/metabolismo , Núcleos Septais/patologiaRESUMO
Korean red pine (Pinus densiflora) belongs to the Genus Pinus, and its bark contains a great amount of naturally occurring phenolic compounds. Until now, few studies have been conducted to assess the neuroprotective effects of Pinus densiflora bark extract against brain ischemic injury. The aim of this study was to investigate the neuroprotective effects of pre-treatment with the extract in the hippocampus following 5-min transient forebrain ischemia in gerbils. Furthermore, this study examined the anti-inflammatory effect as a neuroprotective mechanism of the extract. Pinus densiflora bark was extracted by pure water (100 °C), and this extract was quantitatively analyzed and contained abundant polyphenols, flavonoids, and proanthocyanidins. The extract (25, 50, and 100 mg/kg) was orally administered once a day for seven days before the ischemia. In the gerbil hippocampus, death of the pyramidal neurons was found in the subfield cornu ammonis 1 (CA1) five days after the ischemia. This death was significantly attenuated by pre-treatment with 100 mg/kg, not 25 or 50 mg/kg, of the extract. The treatment with 100 mg/kg of the extract markedly inhibited the activation of microglia (microgliosis) and significantly decreased the expression of pro-inflammatory cytokines (interleukin 1ß and tumor necrosis factor α). In addition, the treatment significantly increased anti-inflammatory cytokines (interleukin 4 and interleukin 13). Taken together, this study clearly indicates that pre-treatment with 100 mg/kg of Pinus densiflora bark extract in gerbils can exert neuroprotection against brain ischemic injury by the attenuation of neuroinflammatory responses.
Assuntos
Anti-Inflamatórios/farmacologia , Isquemia Encefálica/tratamento farmacológico , Hipocampo/efeitos dos fármacos , Fármacos Neuroprotetores/farmacologia , Pinus/química , Prosencéfalo/efeitos dos fármacos , Animais , Anti-Inflamatórios/química , Isquemia Encefálica/genética , Isquemia Encefálica/metabolismo , Isquemia Encefálica/patologia , Flavonoides/química , Flavonoides/farmacologia , Expressão Gênica/efeitos dos fármacos , Gerbillinae , Hipocampo/metabolismo , Hipocampo/patologia , Inflamação , Interleucina-13/agonistas , Interleucina-13/genética , Interleucina-13/metabolismo , Interleucina-1beta/antagonistas & inibidores , Interleucina-1beta/genética , Interleucina-1beta/metabolismo , Interleucina-4/agonistas , Interleucina-4/genética , Interleucina-4/metabolismo , Masculino , Microglia/efeitos dos fármacos , Microglia/metabolismo , Microglia/patologia , Fármacos Neuroprotetores/química , Casca de Planta/química , Extratos Vegetais/química , Extratos Vegetais/farmacologia , Polifenóis/química , Polifenóis/farmacologia , Proantocianidinas/química , Proantocianidinas/farmacologia , Prosencéfalo/metabolismo , Prosencéfalo/patologia , Células Piramidais/efeitos dos fármacos , Células Piramidais/metabolismo , Células Piramidais/patologia , Fator de Necrose Tumoral alfa/antagonistas & inibidores , Fator de Necrose Tumoral alfa/genética , Fator de Necrose Tumoral alfa/metabolismoRESUMO
Fragile X syndrome (FXS) is caused by the loss of fragile X mental retardation protein (FMRP), an RNA-binding protein that can regulate the translation of specific mRNAs. In this study, we developed an FXS human forebrain organoid model and observed that the loss of FMRP led to dysregulated neurogenesis, neuronal maturation and neuronal excitability. Bulk and single-cell gene expression analyses of FXS forebrain organoids revealed that the loss of FMRP altered gene expression in a cell-type-specific manner. The developmental deficits in FXS forebrain organoids could be rescued by inhibiting the phosphoinositide 3-kinase pathway but not the metabotropic glutamate pathway disrupted in the FXS mouse model. We identified a large number of human-specific mRNAs bound by FMRP. One of these human-specific FMRP targets, CHD2, contributed to the altered gene expression in FXS organoids. Collectively, our study revealed molecular, cellular and electrophysiological abnormalities associated with the loss of FMRP during human brain development.
Assuntos
Síndrome do Cromossomo X Frágil/tratamento farmacológico , Síndrome do Cromossomo X Frágil/patologia , Neurogênese/genética , Prosencéfalo/patologia , Adulto , Encéfalo/patologia , Diferenciação Celular , Proteínas de Ligação a DNA/genética , Fenômenos Eletrofisiológicos , Humanos , Masculino , Modelos Neurológicos , Neurogênese/efeitos dos fármacos , Neurônios/patologia , Fosfatidilinositol 3-Quinases/efeitos dos fármacos , Ligação Proteica , Inibidores de Proteínas Quinases/uso terapêutico , RNA Mensageiro/genética , Receptores de Glutamato Metabotrópico/efeitos dos fármacosRESUMO
Traditional Chinese medicines (TCMs) have been a rich source of novel drug discovery, and Cassia seed is one of the common TCMs with numerous biological effects. Based on the existing reports on neuroprotection by Cassia seed extract, the present study aims to search possible pharmacological targets behind the neuroprotective effects of the Cassia seeds by evaluating the functional effect of specific Cassia compounds on various G-protein-coupled receptors. Among the four test compounds (cassiaside, rubrofusarin gentiobioside, aurantio-obtusin, and 2-hydroxyemodin 1-methylether), only aurantio-obtusin demonstrated a specific V1AR antagonist effect (71.80 ± 6.0% inhibition at 100 µM) and yielded an IC50 value of 67.70 ± 2.41 µM. A molecular docking study predicted an additional interaction of the hydroxyl group at C6 and a methoxy group at C7 of aurantio-obtusin with the Ser341 residue as functional for the observed antagonist effect. In the transient brain ischemia/reperfusion injury C57BL/6 mice model, aurantio-obtusin attenuated the latency time that was reduced in the bilateral common carotid artery occlusion (BCCAO) groups. Likewise, compared to neuronal damage in the BCCAO groups, treatment with aurantio-obtusin (10 mg/kg, p.o.) significantly reduced the severity of damage in medial cornu ammonis 1 (mCA1), dorsal CA1, and cortex regions. Overall, the findings of this study highlight V1AR as a possible target of aurantio-obtusin for neuroprotection.
Assuntos
Antraquinonas/farmacologia , Antagonistas dos Receptores de Hormônios Antidiuréticos/química , Fármacos Neuroprotetores/farmacologia , Prosencéfalo/patologia , Receptores de Vasopressinas/química , Animais , Antraquinonas/química , Estenose das Carótidas/metabolismo , Cassia/química , Cromonas/química , Emodina/análogos & derivados , Emodina/química , Éter/química , Glucosídeos/química , Concentração Inibidora 50 , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Simulação de Acoplamento Molecular , Prosencéfalo/metabolismo , Sementes/químicaRESUMO
Adult neurogenesis occurs particularly in the subgranular zone (SGZ) of the hippocampus and the subventricular zone (SVZ) of the lateral ventricle. This continuous addition of neurons to pre-existing neuronal networks is essential for intact cognitive and olfactory functions, respectively. Purinergic signaling modulates adult neurogenesis, however, the role of individual purinergic receptor subtypes in this dynamic process and related cognitive performance is poorly understood. In this study, we analyzed the role of P2Y2 receptor in the neurogenic niches and in related forebrain functions such as spatial working memory and olfaction using mice with a targeted deletion of the P2Y2 receptor (P2Y2-/- ). Proliferation, migration, differentiation, and survival of neuronal precursor cells (NPCs) were analyzed by BrdU assay and immunohistochemistry; signal transduction pathway components were analyzed by immunoblot. In P2Y2-/- mice, proliferation of NPCs in the SGZ and the SVZ was reduced. However, migration, neuronal fate decision, and survival were not affected. Moreover, p-Akt expression was decreased in P2Y2-/- mice. P2Y2-/- mice showed an impaired performance in the Y-maze and a higher latency in the hidden food test. These data indicate that the P2Y2 receptor plays an important role in NPC proliferation as well as in hippocampus-dependent working memory and olfactory function.
Assuntos
Neurogênese , Bulbo Olfatório/patologia , Prosencéfalo/patologia , Receptores Purinérgicos P2Y2/fisiologia , Animais , Movimento Celular , Proliferação de Células , Feminino , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Bulbo Olfatório/metabolismo , Prosencéfalo/metabolismoRESUMO
Mouse models of various neuropsychiatric disorders, such as schizophrenia, often display an immature dentate gyrus, characterized by increased numbers of immature neurons and neuronal progenitors and a dearth of mature neurons. We previously demonstrated that the CRMP5-associated GTPase (CRAG), a short splice variant of Centaurin-γ3/AGAP3, is highly expressed in the dentate gyrus. CRAG promotes cell survival and antioxidant defense by inducing the activation of serum response factors at promyelocytic leukemia protein bodies, which are nuclear stress-responsive domains, during neuronal development. However, the physiological role of CRAG in neuronal development remains unknown. Here, we analyzed the role of CRAG using dorsal forebrain-specific CRAG/Centaurin-γ3 knockout mice. The mice revealed maturational abnormality of the hippocampal granule cells, including increased doublecortin-positive immature neurons and decreased calbindin-positive mature neurons, a typical phenotype of immature dentate gyri. Furthermore, the mice displayed hyperactivity in the open-field test, a common measure of exploratory behavior, suggesting that these mice may serve as a novel model for neuropsychiatric disorder associated with hyperactivity. Thus, we conclude that CRAG is required for the maturation of neurons in the dentate gyrus, raising the possibility that its deficiency might promote the development of psychiatric disorders in humans.
Assuntos
Giro Denteado/patologia , GTP Fosfo-Hidrolases/fisiologia , Células-Tronco Neurais/patologia , Neurogênese , Neurônios/patologia , Prosencéfalo/patologia , Agitação Psicomotora/patologia , Animais , Giro Denteado/metabolismo , Comportamento Exploratório , Feminino , Masculino , Camundongos , Camundongos Knockout , Células-Tronco Neurais/metabolismo , Neurônios/metabolismo , Prosencéfalo/metabolismo , Agitação Psicomotora/etiologia , Agitação Psicomotora/metabolismoRESUMO
Many neurodegenerative diseases are associated with neuronal misfolded protein accumulation, indicating a need for proteostasis-promoting strategies. Here we show that de-repressing the transcription factor Nrf2, epigenetically shut-off in early neuronal development, can prevent protein aggregate accumulation. Using a paradigm of α-synuclein accumulation and clearance, we find that the classical electrophilic Nrf2 activator tBHQ promotes endogenous Nrf2-dependent α-synuclein clearance in astrocytes, but not cortical neurons, which mount no Nrf2-dependent transcriptional response. Moreover, due to neuronal Nrf2 shut-off and consequent weak antioxidant defences, electrophilic tBHQ actually induces oxidative neurotoxicity, via Nrf2-independent Jun induction. However, we find that epigenetic de-repression of neuronal Nrf2 enables them to respond to Nrf2 activators to drive α-synuclein clearance. Moreover, activation of neuronal Nrf2 expression using gRNA-targeted dCas9-based transcriptional activation complexes is sufficient to trigger Nrf2-dependent α-synuclein clearance. Thus, targeting reversal of the developmental shut-off of Nrf2 in forebrain neurons may alter neurodegenerative disease trajectory by boosting proteostasis.
Assuntos
Sistemas CRISPR-Cas , Marcação de Genes , Hidroquinonas/farmacologia , Doença por Corpos de Lewy/terapia , Fator 2 Relacionado a NF-E2/agonistas , Neurônios/metabolismo , Fármacos Neuroprotetores/farmacologia , Prosencéfalo/efeitos dos fármacos , alfa-Sinucleína/metabolismo , Animais , Astrócitos/metabolismo , Astrócitos/patologia , Proteína 9 Associada à CRISPR/genética , Proteína 9 Associada à CRISPR/metabolismo , Morte Celular/efeitos dos fármacos , Células Cultivadas , Repetições Palindrômicas Curtas Agrupadas e Regularmente Espaçadas , Técnicas de Cocultura , Repressão Epigenética , Feminino , Doença por Corpos de Lewy/genética , Doença por Corpos de Lewy/metabolismo , Doença por Corpos de Lewy/patologia , Masculino , Camundongos Endogâmicos C57BL , Camundongos Knockout , Fator 2 Relacionado a NF-E2/genética , Fator 2 Relacionado a NF-E2/metabolismo , Neurônios/efeitos dos fármacos , Neurônios/patologia , Prosencéfalo/metabolismo , Prosencéfalo/patologia , Proteostase/efeitos dos fármacos , alfa-Sinucleína/genéticaRESUMO
Altered expression levels of NmethylDaspartate receptor (NMDAR), a ligandgated ion channel, have a harmful effect on cellular survival. Hyperthermia is a proven risk factor of transient forebrain ischemia (tFI) and can cause extensive and severe brain damage associated with mortality. The objective of the present study was to investigate whether hyperthermic preconditioning affected NMDAR1 immunoreactivity associated with deterioration of neuronal function in the gerbil hippocampal CA1 region following tFI via histological and western blot analyses. Hyperthermic preconditioning was performed for 1 h before tFI, which was developed by ligating common carotid arteries for 5 min. tFIinduced cognitive impairment under hyperthermia was worse compared with that under normothermia. Loss (death) of pyramidal neurons in the CA1 region occurred fast and was more severe under hyperthermia compared with that under normothermia. NMDAR1 immunoreactivity was not observed in the somata of pyramidal neurons of sham gerbils with normothermia. However, its immunoreactivity was strong in the somata and processes at 12 h posttFI. Thereafter, NMDAR1 immunoreactivity decreased with time after tFI. On the other hand, NMDAR1 immunoreactivity under hyperthermia was significantly increased in the somata and processes at 6 h posttFI. The change pattern of NMDAR1 immunoreactivity under hyperthermia was different from that under normothermia. Overall, accelerated tFIinduced neuronal death under hyperthermia may be closely associated with altered NMDAR1 expression compared with that under normothermia.
Assuntos
Isquemia Encefálica/metabolismo , Regulação da Expressão Gênica , Hipocampo/metabolismo , Hipertermia Induzida , Transtornos da Memória/metabolismo , Prosencéfalo/metabolismo , Receptores de N-Metil-D-Aspartato/biossíntese , Animais , Isquemia Encefálica/patologia , Morte Celular , Gerbillinae , Hipocampo/patologia , Masculino , Transtornos da Memória/etiologia , Transtornos da Memória/patologia , Neurônios , Prosencéfalo/patologiaRESUMO
It has been reported that CD200 (Cluster of Differentiation 200), expressed in neurons, regulates microglial activation in the central nervous system, and a decrease in CD200 expression causes an increase in microglial activation and neuronal loss. The aim of this study was to investigate time-dependent changes in CD200 expression in the hippocampus proper (CA1, 2, and 3 fields) after transient forebrain ischemia for 5 min in gerbils. In this study, 5-min ischemia evoked neuronal death (loss) of pyramidal neurons in the CA1 field, but not in the CA2/3 fields, at 5 days postischemia. In the sham group, CD200 expression was found in pyramidal neurons of the CA1 field, and the immunoreactivity in the group with ischemia was decreased at 6 h postischemia, dramatically increased at 12 h postischemia, decreased (to level found at 6 h postischemia) at 1 and 2 days postischemia, and significantly increased again at 5 days postischemia. At 5 days postischemia, CD200 immunoreactivity was strongly expressed in microglia and GABAergic neurons. However, in the CA3 field, the change in CD200 immunoreactivity in pyramidal neurons was markedly weaker than that in the CA1 field, showing there was no expression of CD 200 in microglia and GABAergic neurons. In addition, treatment of 10 mg/kg risperidone (an atypical antipsychotic drug) after the ischemia hardly changed CD200 immunoreactivity in the CA1 field, showing that CA1 pyramidal neurons were protected from the ischemic injury. These results indicate that the transient ischemia-induced change in CD200 expression may be associated with specific and selective neuronal death in the hippocampal CA1 field following transient forebrain ischemia.
Assuntos
Antígenos CD/metabolismo , Região CA1 Hipocampal/efeitos dos fármacos , Ataque Isquêmico Transitório/tratamento farmacológico , Fármacos Neuroprotetores/farmacologia , Risperidona/farmacologia , Animais , Região CA1 Hipocampal/metabolismo , Região CA1 Hipocampal/patologia , Morte Celular/efeitos dos fármacos , Morte Celular/fisiologia , Gerbillinae , Ataque Isquêmico Transitório/patologia , Masculino , Microglia/patologia , Prosencéfalo/irrigação sanguínea , Prosencéfalo/patologia , Células Piramidais/efeitos dos fármacos , Células Piramidais/patologiaRESUMO
Fine-tuned gene expression is crucial for neurodevelopment. The gene expression program is tightly controlled at different levels, including RNA decay. N6-methyladenosine (m6A) methylation-mediated degradation of RNA is essential for brain development. However, m6A methylation impacts not only RNA stability, but also other RNA metabolism processes. How RNA decay contributes to brain development is largely unknown. Here, we show that Exosc10, a RNA exonuclease subunit of the RNA exosome complex, is indispensable for forebrain development. We report that cortical cells undergo overt apoptosis, culminating in cortical agenesis upon conditional deletion of Exosc10 in mouse cortex. Mechanistically, Exosc10 directly binds and degrades transcripts of the P53 signaling-related genes, such as Aen and Bbc3. Overall, our findings suggest a crucial role for Exosc10 in suppressing the P53 pathway, in which the rapid turnover of the apoptosis effectors Aen and Bbc3 mRNAs is essential for cell survival and normal cortical histogenesis.
Assuntos
Sobrevivência Celular/fisiologia , Exossomos/genética , Exossomos/metabolismo , Regulação da Expressão Gênica no Desenvolvimento , Prosencéfalo/crescimento & desenvolvimento , Proteína Supressora de Tumor p53/metabolismo , Animais , Apoptose , Proteínas Reguladoras de Apoptose , Biologia Computacional , Exorribonucleases/genética , Complexo Multienzimático de Ribonucleases do Exossomo/genética , Complexo Multienzimático de Ribonucleases do Exossomo/metabolismo , Humanos , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Prosencéfalo/patologia , RNA/metabolismo , Estabilidade de RNA , Transdução de Sinais/genética , Proteína Supressora de Tumor p53/genética , Proteínas Supressoras de TumorRESUMO
In the present study, we investigated the neuroprotective effect of post-ischemic treatment with oxcarbazepine (OXC; an anticonvulsant compound) against ischemic injury induced by transient forebrain ischemia and its mechanisms in gerbils. Transient ischemia was induced in the forebrain by occlusion of both common carotid arteries for 5 min under normothermic conditions (37 ± 0.2 °C). The ischemic gerbils were treated with vehicle, hypothermia (whole-body cooling; 33.0 ± 0.2 °C), or 200 mg/kg OXC. Post-ischemic treatments with vehicle and hypothermia failed to attenuate and improve, respectively, ischemia-induced hyperactivity and cognitive impairment (decline in spatial and short-term memory). However, post-ischemic treatment with OXC significantly attenuated the hyperactivity and the cognitive impairment, showing that OXC treatment significantly reduced body temperature (to about 33 °C). When the hippocampus was histopathologically examined, pyramidal cells (principal neurons) were dead (lost) in the subfield Cornu Ammonis 1 (CA1) of the gerbils treated with vehicle and hypothermia on Day 4 after ischemia, but these cells were saved in the gerbils treated with OXC. In the gerbils treated with OXC after ischemia, the expression of transient receptor potential vanilloid type 1 (TRPV1; one of the transient receptor potential cation channels) was significantly increased in the CA1 region compared with that in the gerbils treated with vehicle and hypothermia. In brief, our results showed that OXC-induced hypothermia after transient forebrain ischemia effectively protected against ischemia-reperfusion injury through an increase in TRPV1 expression in the gerbil hippocampal CA1 region, indicating that TRPV1 is involved in OXC-induced hypothermia.
Assuntos
Hipotermia Induzida , Isquemia/terapia , Neuroproteção , Fármacos Neuroprotetores/uso terapêutico , Oxcarbazepina/uso terapêutico , Prosencéfalo/patologia , Canais de Cátion TRPV/metabolismo , Animais , Temperatura Corporal/efeitos dos fármacos , Núcleo Celular/efeitos dos fármacos , Núcleo Celular/metabolismo , Cognição/efeitos dos fármacos , Gerbillinae , Hipocampo/efeitos dos fármacos , Hipocampo/patologia , Isquemia/patologia , Isquemia/fisiopatologia , Masculino , Neurônios/efeitos dos fármacos , Neurônios/patologia , Neuroproteção/efeitos dos fármacos , Fármacos Neuroprotetores/farmacologia , Oxcarbazepina/farmacologia , Prosencéfalo/efeitos dos fármacos , Prosencéfalo/fisiopatologiaRESUMO
Rett syndrome (RTT) is a progressive neurodevelopmental disorder, mainly caused by mutations in MeCP2 and currently with no cure. We report here that neurons from R106W MeCP2 RTT human iPSCs as well as human embryonic stem cells after MeCP2 knockdown exhibit consistent and long-lasting impairment in maturation as indicated by impaired action potentials and passive membrane properties as well as reduced soma size and spine density. Moreover, RTT-inherent defects in neuronal maturation could be pan-neuronal and occurred in neurons with both dorsal and ventral forebrain features. Knockdown of MeCP2 led to more severe neuronal deficits as compared to RTT iPSC-derived neurons, which appeared to retain partial function. Strikingly, consistent deficits in nuclear size, dendritic complexity and circuitry-dependent spontaneous postsynaptic currents could only be observed in MeCP2 knockdown neurons but not RTT iPSC-derived neurons. Both neuron-intrinsic and circuitry-dependent deficits of MeCP2-deficient neurons could be fully or partially rescued by re-expression of wild type or T158M MeCP2, strengthening the dosage dependency of MeCP2 on disease phenotypes and also the partial function of the mutant. Our findings thus reveal stable neuronal maturation deficits and unexpectedly, graded sensitivities of neuron-inherent and neural transmission phenotypes towards the extent of MeCP2 deficiency, which is informative for future therapeutic development.
Assuntos
Proteína 2 de Ligação a Metil-CpG/genética , Células-Tronco Neurais/metabolismo , Neurônios/metabolismo , Prosencéfalo/metabolismo , Síndrome de Rett/genética , Potenciais de Ação/genética , Sequência de Bases , Diferenciação Celular , Fibroblastos/citologia , Fibroblastos/metabolismo , Dosagem de Genes , Expressão Gênica , Técnicas de Silenciamento de Genes , Teste de Complementação Genética , Células-Tronco Embrionárias Humanas/citologia , Células-Tronco Embrionárias Humanas/metabolismo , Humanos , Células-Tronco Pluripotentes Induzidas/citologia , Células-Tronco Pluripotentes Induzidas/metabolismo , Proteína 2 de Ligação a Metil-CpG/deficiência , Células-Tronco Neurais/patologia , Neurônios/patologia , Fenótipo , Cultura Primária de Células , Prosencéfalo/patologia , Síndrome de Rett/metabolismo , Síndrome de Rett/patologia , Índice de Gravidade de Doença , Transmissão SinápticaRESUMO
Mucopolysaccharidosis type IIIB (MPS IIIB; Sanfilippo syndrome B) is an autosomal recessive lysosomal storage disorder caused by the deficiency of alpha-N-acetylglucosaminidase activity, leading to increased levels of nondegraded heparan sulfate (HS). A mouse model has been useful to evaluate novel treatments for MPS IIIB, but has limitations. In this study, we evaluated the naturally occurring canine model of MPS IIIB for the onset and progression of biochemical and neuropathological changes during the preclinical stages (onset approximately 24-30 months of age) of canine MPS IIIB disease. Even by 1 month of age, MPS IIIB dogs had elevated HS levels in brain and cerebrospinal fluid. Analysis of histopathology of several disease-relevant regions of the forebrain demonstrated progressive lysosomal storage and microglial activation despite a lack of cerebrocortical atrophy in the oldest animals studied. More pronounced histopathology changes were detected in the cerebellum, where progressive lysosomal storage, astrocytosis and microglial activation were observed. Microglial activation was particularly prominent in cerebellar white matter and within the deep cerebellar nuclei, where neuron loss also occurred. The findings in this study will form the basis of future assessments of therapeutic efficacy in this large animal disease model.
Assuntos
Acetilglucosaminidase/deficiência , Cerebelo/patologia , Córtex Cerebral/patologia , Doenças do Cão/patologia , Mucopolissacaridose III/patologia , Prosencéfalo/patologia , Animais , Astrócitos/metabolismo , Astrócitos/patologia , Cerebelo/metabolismo , Córtex Cerebral/metabolismo , Modelos Animais de Doenças , Progressão da Doença , Doenças do Cão/metabolismo , Cães , Feminino , Heparitina Sulfato/metabolismo , Histocitoquímica , Humanos , Lisossomos/metabolismo , Lisossomos/patologia , Masculino , Microglia/metabolismo , Microglia/patologia , Mucopolissacaridose III/metabolismo , Neurônios/metabolismo , Neurônios/patologia , Prosencéfalo/metabolismo , Substância Branca/metabolismo , Substância Branca/patologiaRESUMO
Stroke is caused by obstructed blood flow (ischaemia) or unrestricted bleeding in the brain (haemorrhage). Global brain ischaemia occurs after restricted cerebral blood flow e.g. during cardiac arrest. Following ischaemic injury, restoration of blood flow causes ischaemia-reperfusion (I/R) injury which worsens outcome. Secondary injury mechanisms after any stroke are similar, and encompass inflammation, endothelial dysfunction, blood-brain barrier (BBB) damage and apoptosis. We developed a new model of transient global forebrain I/R injury (dual carotid artery ligation; DCAL) and compared the manifestations of this injury with those in a conventional I/R injury model (middle-cerebral artery occlusion; MCAo) and with intracerebral haemorrhage (ICH; collagenase model). MRI revealed that DCAL produced smaller bilateral lesions predominantly localised to the striatum, whereas MCAo produced larger focal corticostriatal lesions. After global forebrain ischaemia mice had worse overall neurological scores, although quantitative locomotor assessment showed MCAo and ICH had significantly worsened mobility. BBB breakdown was highest in the DCAL model while apoptotic activity was highest after ICH. VCAM-1 upregulation was specific to ischaemic models only. Differential transcriptional upregulation of pro-inflammatory chemokines and cytokines and TLRs was seen in the three models. Our findings offer a unique insight into the similarities and differences in how biological processes are regulated after different types of stroke. They also establish a platform for analysis of therapies such as endothelial protective and anti-inflammatory agents that can be applied to all types of stroke.
Assuntos
Circulação Cerebrovascular/fisiologia , Acidente Vascular Cerebral Hemorrágico/patologia , AVC Isquêmico/patologia , Prosencéfalo/irrigação sanguínea , Traumatismo por Reperfusão/patologia , Animais , Anti-Inflamatórios/uso terapêutico , Apoptose/imunologia , Barreira Hematoencefálica/diagnóstico por imagem , Barreira Hematoencefálica/efeitos dos fármacos , Barreira Hematoencefálica/patologia , Artérias Carótidas/fisiopatologia , Circulação Cerebrovascular/efeitos dos fármacos , Colagenases/administração & dosagem , Colagenases/efeitos adversos , Citocinas/genética , Citocinas/imunologia , Modelos Animais de Doenças , Endotélio Vascular/efeitos dos fármacos , Endotélio Vascular/patologia , Acidente Vascular Cerebral Hemorrágico/tratamento farmacológico , Acidente Vascular Cerebral Hemorrágico/imunologia , Acidente Vascular Cerebral Hemorrágico/fisiopatologia , Humanos , AVC Isquêmico/tratamento farmacológico , AVC Isquêmico/imunologia , AVC Isquêmico/fisiopatologia , Ligadura , Locomoção/fisiologia , Imageamento por Ressonância Magnética , Masculino , Camundongos , Artéria Cerebral Média/fisiopatologia , Prosencéfalo/diagnóstico por imagem , Prosencéfalo/efeitos dos fármacos , Prosencéfalo/patologia , Substâncias Protetoras/uso terapêutico , Traumatismo por Reperfusão/tratamento farmacológico , Traumatismo por Reperfusão/imunologia , Traumatismo por Reperfusão/fisiopatologia , Receptores Toll-Like/genética , Ativação Transcricional/imunologiaRESUMO
Forkhead box G1 (FOXG1) is a transcription factor mainly expressed in the brain that plays a critical role in the development and regionalization of the forebrain. Aberrant expression of FOXG1 has implications in FOXG1 syndrome, a serious neurodevelopmental disorder. Here, we report the crystal structure of the FOXG1 DNA-binding domain (DBD) in complex with the forkhead consensus DNA site DBE2 at the resolution of 1.6 Å. FOXG1-DBD adopts a typical winged helix fold. Compared to those of other FOX-DBD/DBE2 structures, the N terminus, H3 helix and wing2 region of FOXG1-DBD exhibit differences in DNA recognition. The FOXG1-DBD wing2 region adopts a unique architecture composed of two ß-strands that differs from all other known FOX-DBD wing2 folds. Mutation assays revealed that the disease-causing mutations within the FOXG1-DBD affect DNA binding, protein thermal stability, or both. Our report provides initial insight into how FOXG1 binds DNA and sheds light on how disease-causing mutations in FOXG1-DBD affect its DNA-binding ability.
Assuntos
Proteínas de Ligação a DNA/ultraestrutura , Fatores de Transcrição Forkhead/ultraestrutura , Proteínas do Tecido Nervoso/ultraestrutura , Transtornos do Neurodesenvolvimento/genética , Conformação Proteica , Cristalografia por Raios X , DNA/genética , Proteínas de Ligação a DNA/genética , Fatores de Transcrição Forkhead/genética , Regulação da Expressão Gênica/genética , Predisposição Genética para Doença , Humanos , Mutação/genética , Proteínas do Tecido Nervoso/genética , Transtornos do Neurodesenvolvimento/patologia , Prosencéfalo/metabolismo , Prosencéfalo/patologiaRESUMO
Cerebral hernia in crested chicken has been characterized as the protrusion of cerebral hemispheres into the unsealed skull for hundreds of years, since Charles Darwin. The development of deformed forebrain (telencephalon) of cerebral hernia remains largely unknown. Here, the unsealed frontal skull combined with misplaced sphenoid bone was observed and potentially associated with brain protuberance. The shifted pallidum, elongated hippocampus, expanded mesopallium and nidopallium, and reduced hyperpallium were observed in seven regions of the malformed telencephalon. The neurons were detected with nuclear pyknosis and decreased density. Astrocytes showed uneven distribution and disordered protuberances in hyperpallium and hippocampus. Transcriptome analyses of chicken telencephalon (cerebral hernia vs. control) revealed 547 differentially expressed genes (DEGs), mainly related to nervous system development, and immune system processes, including astrocyte marker gene GFAP, and neuron and astrocyte developmental gene S100A6. The upregulation of GFAP and S100A6 genes in abnormal telencephalon was correlated with reduced DNA methylation levels in the promoter regions. The morphological, cellular, and molecular variations in the shape, regional specification, and cellular states of malformed telencephalon potentially participate in brain plasticity and previously reported behavior changes. Chickens with cerebral hernia might be an interesting and valuable disease model to further explore the recognition, diagnosis, and therapy of cerebral hernia development of crested chickens and other species.