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1.
Cell ; 151(1): 25-40, 2012 Sep 28.
Artigo em Inglês | MEDLINE | ID: mdl-23021213

RESUMO

Astrocytes release glutamate upon activation of various GPCRs to exert important roles in synaptic functions. However, the molecular mechanism of release has been controversial. Here, we report two kinetically distinct modes of nonvesicular, channel-mediated glutamate release. The fast mode requires activation of G(αi), dissociation of G(ßγ), and subsequent opening of glutamate-permeable, two-pore domain potassium channel TREK-1 through direct interaction between G(ßγ) and N terminus of TREK-1. The slow mode is Ca(2+) dependent and requires G(αq) activation and opening of glutamate-permeable, Ca(2+)-activated anion channel Best1. Ultrastructural analyses demonstrate that TREK-1 is preferentially localized at cell body and processes, whereas Best1 is mostly found in microdomains of astrocytes near synapses. Diffusion modeling predicts that the fast mode can target neuronal mGluR with peak glutamate concentration of 100 µM, whereas slow mode targets neuronal NMDA receptors at around 1 µM. Our results reveal two distinct sources of astrocytic glutamate that can differentially influence neighboring neurons.


Assuntos
Astrócitos/metabolismo , Proteínas do Olho/metabolismo , Ácido Glutâmico/metabolismo , Canais Iônicos/metabolismo , Canais de Potássio de Domínios Poros em Tandem/metabolismo , Receptores Acoplados a Proteínas G/metabolismo , Sequência de Aminoácidos , Animais , Bestrofinas , Células Cultivadas , Exocitose , Proteínas do Olho/genética , Células HEK293 , Humanos , Canais Iônicos/genética , Camundongos , Camundongos Knockout , Dados de Sequência Molecular , Canais de Potássio de Domínios Poros em Tandem/genética , Alinhamento de Sequência , Transdução de Sinais
2.
EMBO J ; 39(6): e102214, 2020 03 16.
Artigo em Inglês | MEDLINE | ID: mdl-32030804

RESUMO

Spinal cord microglia contribute to nerve injury-induced neuropathic pain. We have previously demonstrated that toll-like receptor 2 (TLR2) signaling is critical for nerve injury-induced activation of spinal cord microglia, but the responsible endogenous TLR2 agonist has not been identified. Here, we show that nerve injury-induced upregulation of sialyltransferase St3gal2 in sensory neurons leads to an increase in expression of the sialylated glycosphingolipid, GT1b. GT1b ganglioside is axonally transported to the spinal cord dorsal horn and contributes to characteristics of neuropathic pain such as mechanical and thermal hypersensitivity. Spinal cord GT1b functions as an TLR2 agonist and induces proinflammatory microglia activation and central sensitization. Pharmacological inhibition of GT1b synthesis attenuates nerve injury-induced spinal cord microglia activation and pain hypersensitivity. Thus, the St3gal2-GT1b-TLR2 axis may offer a novel therapeutic target for the treatment of neuropathic pain.


Assuntos
Gangliosídeos/metabolismo , Neuralgia/terapia , Traumatismos dos Nervos Periféricos/terapia , Transdução de Sinais , Receptor 2 Toll-Like/agonistas , Animais , Gangliosídeos/antagonistas & inibidores , Regulação da Expressão Gênica , Inflamação , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Microglia/metabolismo , Neuralgia/etiologia , Traumatismos dos Nervos Periféricos/etiologia , Ratos , Ratos Sprague-Dawley , Células Receptoras Sensoriais , Sialiltransferases/genética , Sialiltransferases/metabolismo , Medula Espinal/metabolismo , Receptor 2 Toll-Like/metabolismo
3.
J Nanobiotechnology ; 20(1): 367, 2022 Aug 11.
Artigo em Inglês | MEDLINE | ID: mdl-35953847

RESUMO

BACKGROUND: Astrocyte is a key regulator of neuronal activity and excitatory/inhibitory balance via gliotransmission. Recently, gliotransmission has been identified as a novel target for neurological diseases. However, using the properties of nanomaterials to modulate gliotransmission has not been uncovered. RESULTS: We prepared non-invasive CNT platforms for cells with different nanotopography and properties such as hydrophilicity and conductivity. Using CNT platforms, we investigated the effect of CNT on astrocyte functions participating in synaptic transmission by releasing gliotransmitters. Astrocytes on CNT platforms showed improved cell adhesion and proliferation with upregulated integrin and GFAP expression. In addition, intracellular GABA and glutamate in astrocytes were augmented on CNT platforms. We also demonstrated that gliotransmitters in brain slices were increased by ex vivo incubation with CNT. Additionally, intracellular resting Ca2+ level, which is important for gliotransmission, was also increased via TRPV1 on CNT platforms. CONCLUSION: CNT can improve astrocyte function including adhesion, proliferation and gliotransmission by increasing resting Ca2+ level. Therefore, our study suggests that CNT would be utilized as a new therapeutic platform for central nervous system diseases by modulating gliotransmission.


Assuntos
Nanotubos de Carbono , Astrócitos , Encéfalo , Neurônios/metabolismo , Transmissão Sináptica/fisiologia
4.
Proc Natl Acad Sci U S A ; 115(19): 5004-5009, 2018 05 08.
Artigo em Inglês | MEDLINE | ID: mdl-29691318

RESUMO

Tonic inhibition in the brain is mediated through an activation of extrasynaptic GABAA receptors by the tonically released GABA, resulting in a persistent GABAergic inhibitory action. It is one of the key regulators for neuronal excitability, exerting a powerful action on excitation/inhibition balance. We have previously reported that astrocytic GABA, synthesized by monoamine oxidase B (MAOB), mediates tonic inhibition via GABA-permeable bestrophin 1 (Best1) channel in the cerebellum. However, the role of astrocytic GABA in regulating neuronal excitability, synaptic transmission, and cerebellar brain function has remained elusive. Here, we report that a reduction of tonic GABA release by genetic removal or pharmacological inhibition of Best1 or MAOB caused an enhanced neuronal excitability in cerebellar granule cells (GCs), synaptic transmission at the parallel fiber-Purkinje cell (PF-PC) synapses, and motor performance on the rotarod test, whereas an augmentation of tonic GABA release by astrocyte-specific overexpression of MAOB resulted in a reduced neuronal excitability, synaptic transmission, and motor performance. The bidirectional modulation of astrocytic GABA by genetic alteration of Best1 or MAOB was confirmed by immunostaining and in vivo microdialysis. These findings indicate that astrocytes are the key player in motor coordination through tonic GABA release by modulating neuronal excitability and could be a good therapeutic target for various movement and psychiatric disorders, which show a disturbed excitation/inhibition balance.


Assuntos
Astrócitos/metabolismo , Cerebelo/metabolismo , Desempenho Psicomotor/fisiologia , Células de Purkinje/metabolismo , Transmissão Sináptica/fisiologia , Ácido gama-Aminobutírico/metabolismo , Animais , Astrócitos/citologia , Bestrofinas/genética , Bestrofinas/metabolismo , Cerebelo/citologia , Camundongos Endogâmicos BALB C , Camundongos Knockout , Monoaminoxidase/genética , Monoaminoxidase/metabolismo , Células de Purkinje/citologia , Ácido gama-Aminobutírico/genética
5.
Arterioscler Thromb Vasc Biol ; 39(4): 675-684, 2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-30786743

RESUMO

Objective- Increasing evidence shows that resveratrol has antiatherogenic effects, but its underlying mechanisms are unknown. Thus, we evaluated the molecular mechanisms underlying the antiatherogenic effect of resveratrol. Approach and Results- Using the previously established mouse atherosclerosis model of partial ligation of the left carotid artery, we evaluated the role of resveratrol in antiatherosclerosis. We attempted to determine the mechanisms associated with focal adhesions using vascular endothelial cells. The results showed that resveratrol stimulated focal adhesion kinase cleavage via resveratrol-increased expression of lactoferrin in endothelial cells. Furthermore, we found that an N-terminal focal adhesion kinase fragment cleaved by resveratrol contained the FERM (band 4.1, ezrin, radixin, and moesin)-kinase domain. Furthermore, resveratrol inhibited lipopolysaccharide-stimulated adhesion of THP-1 human monocytes by decreased expression of ICAM-1 (intercellular adhesion molecule-1). A decreased ICAM-1 level was also observed in the left carotid artery of mice treated with resveratrol. To understand the relationship between resveratrol-induced antiinflammation and focal adhesion disruption, endothelial cells were transfected with FERM-kinase. Ectopically expressed FERM-kinase, the resveratrol-cleaved focal adhesion kinase fragment, was found in the nuclear fraction and inhibited the transcription level of icam-1 via the Nrf2 (nuclear factor erythroid 2-related factor 2)-antioxidant response element complex. Finally, ectopically expressed FERM-kinase blocked tumor necrosis factor-α- or IL- (interleukin) stimulated monocytic binding to endothelial cells. Conclusions- Our results show that resveratrol inhibits the expression of ICAM-1 via transcriptional regulation of the FERM-kinase and Nrf2 interaction, thereby blocking monocyte adhesion. These suppressive effects on the inflammatory mechanism suggest that resveratrol delayed the onset of atherosclerosis.


Assuntos
Aterosclerose/prevenção & controle , Adesão Celular/efeitos dos fármacos , Monócitos/efeitos dos fármacos , Resveratrol/farmacologia , Transporte Ativo do Núcleo Celular , Animais , Aterosclerose/metabolismo , Aterosclerose/patologia , Artérias Carótidas/efeitos dos fármacos , Artérias Carótidas/metabolismo , Estenose das Carótidas , Modelos Animais de Doenças , Regulação para Baixo/efeitos dos fármacos , Endotélio Vascular/metabolismo , Indução Enzimática , Quinase 1 de Adesão Focal/biossíntese , Quinase 1 de Adesão Focal/metabolismo , Inflamação , Lactoferrina/metabolismo , Ligadura , Camundongos , Camundongos Knockout para ApoE , Monócitos/metabolismo , Fator 2 Relacionado a NF-E2/metabolismo , Distribuição Aleatória , Transcrição Gênica
6.
Eur J Neurosci ; 42(7): 2467-77, 2015 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-26215659

RESUMO

Histamine, a neurotransmitter/neuromodulator implicated in the control of arousal state, exerts a potent phase-shifting effect on the circadian clock in the rodent suprachiasmatic nucleus (SCN). In this study, the mechanisms by which histamine resets the circadian clock in the mouse SCN were investigated. As a first step, Ca(2+) -imaging techniques were used to demonstrate that histamine increases intracellular Ca(2+) concentration ([Ca(2+) ]i ) in acutely dissociated SCN neurons and that this increase is blocked by the H1 histamine receptor (H1R) antagonist pyrilamine, the removal of extracellular Ca(2+) and the L-type Ca(2+) channel blocker nimodipine. The histamine-induced Ca(2+) transient is reduced, but not blocked, by application of the ryanodine receptor (RyR) blocker dantrolene. Immunohistochemical techniques indicated that CaV 1.3 L-type Ca(2+) channels are expressed mainly in the somata of SCN cells along with the H1R, whereas CaV 1.2 channels are located primarily in the processes. Finally, extracellular single-unit recordings demonstrated that the histamine-elicited phase delay of the circadian neural activity rhythm recorded from SCN slices is blocked by pyrilamine, nimodipine and the knockout of CaV 1.3 channel. Again, application of dantrolene reduced but did not block the histamine-induced phase delays. Collectively, these results indicate that, to reset the circadian clock, histamine increases [Ca(2+) ]i in SCN neurons by activating CaV 1.3 channels through H1R, and secondarily by causing Ca(2+) -induced Ca(2+) release from RyR-mediated internal stores.


Assuntos
Canais de Cálcio Tipo L/metabolismo , Relógios Circadianos/fisiologia , Histamina/fisiologia , Receptores Histamínicos H1/metabolismo , Canal de Liberação de Cálcio do Receptor de Rianodina/metabolismo , Núcleo Supraquiasmático/metabolismo , Animais , Bloqueadores dos Canais de Cálcio/farmacologia , Dantroleno/farmacologia , Antagonistas dos Receptores Histamínicos H1/farmacologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Nimodipina/farmacologia , Pirilamina/farmacologia , Transdução de Sinais
7.
J Nanobiotechnology ; 13: 92, 2015 Dec 18.
Artigo em Inglês | MEDLINE | ID: mdl-26683698

RESUMO

BACKGROUND: Multi-walled carbon nanotubes (MW-CNTs) have been extensively explored for their possible beneficial use in the nervous system. CNTs have shown to modulate neuronal growth and electrical properties, but its effect that varying length of MW-CNTs on primary astrocyte roles have not been clearly demonstrated yet. RESULTS: We investigate here the effect of MW-CNTs on astrocytic morphology, cell-cell interaction and the distribution of intracellular GABA (gamma-amino butyric acid). Primary cultured cortical astrocytes on MW-CNT-coated glass coverslips grow rounder and make more cell-cell interactions, with many cell processes, compared to astrocytes on poly-D-lysine (PDL) coverslips. In addition, intracellular GABA spreads into the cell processes of astrocytes on MW-CNT coverslips. When this GABA spreads into cell processes from the cell body GABA can be released more easily and in larger quantities compared to astrocytes on PDL coverslips. CONCLUSIONS: Our result confirm that MW-CNTs modulate astrocytic morphology, the distribution of astrocytic GABA, cell-cell interactions and the extension of cell processes. CNTs look to be a promising material for use neuroprosthetics such as brain-machine interface technologies.


Assuntos
Astrócitos/metabolismo , Junções Intercelulares/metabolismo , Nanotubos de Carbono/química , Ácido gama-Aminobutírico/metabolismo , Animais , Animais Recém-Nascidos , Astrócitos/efeitos dos fármacos , Astrócitos/ultraestrutura , Interfaces Cérebro-Computador/estatística & dados numéricos , Comunicação Celular , Córtex Cerebral/efeitos dos fármacos , Córtex Cerebral/metabolismo , Córtex Cerebral/ultraestrutura , Junções Intercelulares/efeitos dos fármacos , Junções Intercelulares/ultraestrutura , Camundongos , Camundongos Endogâmicos BALB C , Polilisina/química , Polilisina/farmacologia , Cultura Primária de Células
8.
J Physiol ; 592(22): 4951-68, 2014 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-25239459

RESUMO

GABA is the major inhibitory transmitter in the brain and is released not only from a subset of neurons but also from glia. Although neuronal GABA is well known to be synthesized by glutamic acid decarboxylase (GAD), the source of glial GABA is unknown. After estimating the concentration of GABA in Bergmann glia to be around 5-10 mM by immunogold electron microscopy, we demonstrate that GABA production in glia requires MAOB, a key enzyme in the putrescine degradation pathway. In cultured cerebellar glia, both Ca(2+)-induced and tonic GABA release are significantly reduced by both gene silencing of MAOB and the MAOB inhibitor selegiline. In the cerebellum and striatum of adult mice, general gene silencing, knock out of MAOB or selegiline treatment resulted in elimination of tonic GABA currents recorded from granule neurons and medium spiny neurons. Glial-specific rescue of MAOB resulted in complete rescue of tonic GABA currents. Our results identify MAOB as a key synthesizing enzyme of glial GABA, which is released via bestrophin 1 (Best1) channel to mediate tonic inhibition in the brain.


Assuntos
Monoaminoxidase/metabolismo , Neuroglia/metabolismo , Ácido gama-Aminobutírico/metabolismo , Animais , Cálcio/metabolismo , Células Cultivadas , Cerebelo/citologia , Cerebelo/metabolismo , Corpo Estriado/citologia , Corpo Estriado/metabolismo , Feminino , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Monoaminoxidase/genética , Inibição Neural , Neuroglia/fisiologia
9.
Proc Natl Acad Sci U S A ; 107(33): 14857-62, 2010 Aug 17.
Artigo em Inglês | MEDLINE | ID: mdl-20682748

RESUMO

Endogenous opioids generate analgesic signals in the periaqueductal gray (PAG). However, because cell types in the PAG are difficult to identify, its neuronal mechanism has remained poorly understood. To address this issue, we characterized PAG neurons by their electrical properties using differentially labeled GABAergic and output neurons in the PAG. We found that GABAergic neurons were mostly fast-spiking cells and could be further divided into two distinct classes: with or without low-threshold spikes (LTS) driven by T-type channels. In contrast, the PAG output neurons lacked LTS and showed heterogeneous firing patterns. To reveal the function of the LTS, we examined the mutant mice lacking the alpha1G T-type channels (alpha1G(-/-)). The mutant mice lacked LTS in the fast-spiking GABAergic neurons of the PAG and unexpectedly showed impaired opioid-dependent analgesia; a similar phenotype was reproduced in PAG-specific alpha1G-knockdown mice. Electrophysiological analyses revealed functional expression of mu-opioid receptors in the low threshold-spiking GABAergic neurons. These neurons in the mutant lacking LTS showed markedly enhanced discharge activities, which led to an augmented inhibition of output neurons. Furthermore, the impaired analgesia observed in alpha1G(-/-) mice was reversed by blocking local GABA(A) receptors. These results indicate that alpha1G T-type channels are critical for the opioidergic descending analgesia system in the PAG.


Assuntos
Analgésicos Opioides/metabolismo , Canais de Cálcio Tipo T/fisiologia , Neurônios/fisiologia , Substância Cinzenta Periaquedutal/fisiologia , Analgésicos Opioides/farmacologia , Animais , Bicuculina/farmacologia , Canais de Cálcio Tipo T/genética , Feminino , Antagonistas GABAérgicos/farmacologia , Antagonistas de Receptores de GABA-A , Proteínas de Fluorescência Verde/genética , Proteínas de Fluorescência Verde/metabolismo , Hibridização in Situ Fluorescente , Masculino , Potenciais da Membrana/efeitos dos fármacos , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Endogâmicos , Camundongos Knockout , Camundongos Transgênicos , Microscopia Confocal , Neurônios/metabolismo , Dor/fisiopatologia , Dor/prevenção & controle , Medição da Dor/métodos , Substância Cinzenta Periaquedutal/citologia , Substância Cinzenta Periaquedutal/metabolismo , Interferência de RNA , Receptores de GABA-A/metabolismo
10.
Biomedicines ; 11(5)2023 Apr 24.
Artigo em Inglês | MEDLINE | ID: mdl-37238931

RESUMO

Animal models of attention-deficit/hyperactivity disorder (ADHD) have been used to study and understand the behavioral, neural, and physiological mechanisms underlying ADHD. These models allow researchers to conduct controlled experiments and manipulate specific brain regions or neurotransmitter systems to investigate the underlying causes of ADHD and test potential drug targets or treatments. However, it is essential to note that while these models can provide valuable insights, they do not ideally mimic the complex and heterogeneous nature of ADHD and should be interpreted cautiously. Additionally, since ADHD is a multifactorial disorder, environmental and epigenetic factors should be considered simultaneously. In this review, the animal models of ADHD reported thus far are classified into genetic, pharmacological, and environmental models, and the limitations of the representative models are discussed. Furthermore, we provide insights into a more reliable alternative model for the comprehensive study of ADHD.

11.
Life (Basel) ; 13(3)2023 Mar 02.
Artigo em Inglês | MEDLINE | ID: mdl-36983841

RESUMO

ADHD is a typical neurodevelopmental disorder with a high prevalence rate. NSCs in the subventricular zone (SVZ) are closely related to neurodevelopmental disorder and can affect olfactory function by neurogenesis and migratory route. Although olfactory dysfunction is one of the symptoms of ADHD, the relevance of cells in the olfactory bulb derived from NSCs has not been studied. Therefore, we investigated olfactory memory and NSCs in Git1-deficient mice, under the ADHD model. Interestingly, only adult male G protein-coupled receptor kinase-interacting protein-1 (GIT1)-deficient (+/-, HE) mice showed impaired olfactory memory, suggesting sex and age dependence. We performed adult NSCs culture from the SVZ and observed distinct cell population in both sex and genotype. Taken together, our study suggests that the altered differentiation of NSCs in GIT1+/- mice can contribute to olfactory dysfunction in ADHD.

12.
Front Bioeng Biotechnol ; 11: 1261255, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37854881

RESUMO

Introduction: Astrocytes play crucial role in modulating immune response in the damaged central nervous system. Numerous studies have investigated the relationship between immune responses in astrocytes and brain diseases. However, the potential application of nanomaterials for alleviating neuroinflammation induced by astrocytes remains unexplored. Method: In this study, we utilized electrophoretic deposition (EPD) to coat graphene oxide (GO) onto titanium (Ti) to enhance the bioactivity of Ti. Results: We confirmed that GO-Ti could improve cell adhesion and proliferation of astrocytes with upregulated integrins and glial fibrillary acidic protein (GFAP) expression. Moreover, we observed that astrocytes on GO-Ti exhibited a heightened immune response when exposed to lipopolysaccharide (LPS). Although pro-inflammatory cytokines increased, anti-inflammatory cytokines and brain-derived neurotrophic factors involved in neuroprotective effects were also augmented through nuclear localization of the yes-associated protein (YAP) and nuclear factor kappa B (NF-κB). Discussion: Taken together, GO-Ti could enhance the neuroprotective function of astrocytes by upregulating the expression of anti-inflammatory cytokines and neuroprotective factors with improved cell adhesion and viability. Consequently, our findings suggest that GO-Ti has the potential to induce neuroprotective effects by regulating cell activity.

13.
Exp Mol Med ; 55(6): 1232-1246, 2023 06.
Artigo em Inglês | MEDLINE | ID: mdl-37258580

RESUMO

SIRT1, a member of the mammalian sirtuin family, is a nicotinamide adenosine dinucleotide (NAD)-dependent deacetylase with key roles in aging-related diseases and cellular senescence. However, the mechanism by which SIRT1 protein homeostasis is controlled under senescent conditions remains elusive. Here, we revealed that SIRT1 protein is significantly downregulated due to ubiquitin-mediated proteasomal degradation during stress-induced premature senescence (SIPS) and that SIRT1 physically associates with anaphase-promoting complex/cyclosome (APC/C), a multisubunit E3 ubiquitin ligase. Ubiquitin-dependent SIRT1 degradation is stimulated by the APC/C coactivator Cdh1 and not by the coactivator Cdc20. We found that Cdh1 depletion impaired the SIPS-promoted downregulation of SIRT1 expression and reduced cellular senescence, likely through SIRT1-driven p53 inactivation. In contrast, AROS, a SIRT1 activator, reversed the SIRT1 degradation induced by diverse stressors and antagonized Cdh1 function through competitive interactions with SIRT1. Furthermore, our data indicate opposite roles for Cdh1 and AROS in the epigenetic regulation of the senescence-associated secretory phenotype genes IL-6 and IL-8. Finally, we demonstrated that pinosylvin restores downregulated AROS (and SIRT1) expression levels in bleomycin-induced mouse pulmonary senescent tissue while repressing bleomycin-promoted Cdh1 expression. Overall, our study provides the first evidence of the reciprocal regulation of SIRT1 stability by APC/C-Cdh1 and AROS during stress-induced premature senescence, and our findings suggest pinosylvin as a potential senolytic agent for pulmonary fibrosis.


Assuntos
Epigênese Genética , Sirtuína 1 , Animais , Camundongos , Ciclossomo-Complexo Promotor de Anáfase/genética , Ciclossomo-Complexo Promotor de Anáfase/metabolismo , Proteínas de Ciclo Celular/metabolismo , Senescência Celular , Sirtuína 1/genética , Sirtuína 1/metabolismo , Ubiquitina/metabolismo , Ubiquitinação
14.
Nat Neurosci ; 26(9): 1541-1554, 2023 09.
Artigo em Inglês | MEDLINE | ID: mdl-37563296

RESUMO

Social hierarchy is established as an outcome of individual social behaviors, such as dominance behavior during long-term interactions with others. Astrocytes are implicated in optimizing the balance between excitatory and inhibitory (E/I) neuronal activity, which may influence social behavior. However, the contribution of astrocytes in the prefrontal cortex to dominance behavior is unclear. Here we show that dorsomedial prefrontal cortical (dmPFC) astrocytes modulate E/I balance and dominance behavior in adult male mice using in vivo fiber photometry and two-photon microscopy. Optogenetic and chemogenetic activation or inhibition of dmPFC astrocytes show that astrocytes bidirectionally control male mouse dominance behavior, affecting social rank. Dominant and subordinate male mice present distinct prefrontal synaptic E/I balance, regulated by astrocyte activity. Mechanistically, we show that dmPFC astrocytes control cortical E/I balance by simultaneously enhancing presynaptic-excitatory and reducing postsynaptic-inhibitory transmission via astrocyte-derived glutamate and ATP release, respectively. Our findings show how dmPFC astrocyte-neuron communication can be involved in the establishment of social hierarchy in adult male mice.


Assuntos
Astrócitos , Sinapses , Camundongos , Animais , Masculino , Sinapses/fisiologia , Astrócitos/fisiologia , Neurônios/fisiologia , Córtex Pré-Frontal , Transmissão Sináptica/fisiologia
15.
Neurochem Res ; 37(11): 2474-9, 2012 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-22700085

RESUMO

GABA (gamma-aminobutyric acid) is considered to be the major inhibitory neurotransmitter that is synthesized in and released from GABA-ergic neurons in the brain. However, recent studies have shown that not only neurons but astrocytes contain a considerable amount of GABA, which can be released and activate the receptors responsive to GABA. In addition, astrocytes are themselves responsive to GABA by expressing GABA receptors. These exciting new findings raise more questions about the origin of GABA, whether it is synthesized or taken up, and about the role of astrocytic GABA and GABA receptors. In this review, we propose several potential pathways for astrocytes to accumulate GABA and discuss the evidence for functional expression of GABA receptors in astrocytes.


Assuntos
Astrócitos/citologia , Ácido gama-Aminobutírico/metabolismo , Animais , Astrócitos/metabolismo , Humanos
16.
Front Cell Neurosci ; 16: 954807, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36072563

RESUMO

Lead (Pb) is one of the most prevalent heavy metals we encounter daily. Although there are many reports regarding their toxic effects on humans, the effects of exposure to low lead concentrations throughout the pregnancy period on the offspring are not fully elucidated yet. This study aimed to investigate the cellular mechanisms that occur in response to lead exposure. To this end, we administered lead-containing water to pregnant mice from the day of conception till delivery or till day 28 postnatally. Furthermore, we performed neurodevelopmental disorder-related behavior tests and RNA-sequencing analysis. We used both genders for all experiments because neurodevelopmental disorders usually show several sex-dependent differences. The results revealed increased levels of gliosis in the cerebella of lead-exposed pups compared to those in littermates belonging to the control group. Additionally, we observed altered behaviors of male mice in the autism spectrum disorder-related tests. RNA-sequencing results revealed changes in gamma-aminobutyric acid (GABA) signaling in the lead-exposed mouse model. Specifically, the lead-exposed male mice showed decreased monoamine oxidase B and increased levels of diamine oxidase enzyme, which is related to the synthesis of GABA in astrocytes. These findings demonstrate sex-dependent basal developmental changes in glial cells and an increased prevalence of autistic-like behaviors in the young pups of mothers exposed to lead during pregnancy.

17.
Exp Neurobiol ; 31(3): 147-157, 2022 Jun 30.
Artigo em Inglês | MEDLINE | ID: mdl-35786638

RESUMO

The principal inhibitory transmitter, γ-aminobutyric acid (GABA), is critical for maintaining hypothalamic homeostasis and released from neurons phasically, as well as from astrocytes tonically. Although astrocytes in the arcuate nucleus (ARC) of the hypothalamus are shown to transform into reactive astrocytes, the tonic inhibition by astrocytic GABA has not been adequately investigated in diet-induced obesity (DIO). Here, we investigated the expression of monoamine oxidase-B (MAOB), a GABA-synthesizing enzyme, in reactive astrocytes in obese mice. We observed that a chronic high-fat diet (HFD) significantly increased astrocytic MAOB and cellular GABA content, along with enhanced hypertrophy of astrocytes in the ARC. Unexpectedly, we found that the level of tonic GABA was unaltered in chronic HFD mice using whole-cell patch-clamp recordings in the ARC. Furthermore, the GABA-induced current was increased with elevated GABAA receptor α5 (GABRA5) expression. Surprisingly, we found that a nonselective GABA transporter (GAT) inhibitor, nipecotic acid (NPA)-induced current was significantly increased in chronic HFD mice. We observed that GAT1 inhibitor, NO711-induced current was significantly increased, whereas GAT3 inhibitor, SNAP5114-induced current was not altered. The unexpected unaltered tonic inhibition was due to an increase of GABA clearance in the ARC by neuronal GAT1 rather than astrocytic GAT3. These results imply that increased astrocytic GABA synthesis and neuronal GABAA receptor were compensated by GABA clearance, resulting in unaltered tonic GABA inhibition in the ARC of the hypothalamus in obese mice. Taken together, GABA-related molecular pathways in the ARC dynamically regulate the tonic inhibition to maintain hypothalamic homeostasis against the HFD challenge.

18.
Exp Neurobiol ; 31(3): 158-172, 2022 06 30.
Artigo em Inglês | MEDLINE | ID: mdl-35786639

RESUMO

Monoamine oxidase B (MAOB) is a key enzyme for GABA production in astrocytes in several brain regions. To date, the role of astrocytic MAOB has been studied in MAOB null knockout (KO) mice, although MAOB is expressed throughout the body. Therefore, there has been a need for genetically engineered mice in which only astrocytic MAOB is targeted. Here, we generated an astrocyte-specific MAOB conditional KO (cKO) mouse line and characterized it in the cerebellar and striatal regions of the brain. Using the CRISPR-Cas9 gene-editing technique, we generated Maob floxed mice (B6-Maobem1Cjl/Ibs) which have floxed exons 2 and 3 of Maob with two loxP sites. By crossing these mice with hGFAP-CreERT2, we obtained Maob floxed::hGFAP-CreERT2 mice which have a property of tamoxifen-inducible ablation of Maob under the human GFAP (hGFAP) promoter. When we treated Maob floxed::hGFAP-CreERT2 mice with tamoxifen for 5 consecutive days, MAOB and GABA immunoreactivity were significantly reduced in striatal astrocytes as well as in Bergmann glia and lamellar astrocytes in the cerebellum, compared to sunflower oil-injected control mice. Moreover, astrocyte-specific MAOB cKO led to a 74.6% reduction in tonic GABA currents from granule cells and a 76.8% reduction from medium spiny neurons. Our results validate that astrocytic MAOB is a critical enzyme for the synthesis of GABA in astrocytes. We propose that this new mouse line could be widely used in studies of various brain diseases to elucidate the pathological role of astrocytic MAOB in the future.

19.
Cells ; 9(10)2020 09 27.
Artigo em Inglês | MEDLINE | ID: mdl-32992620

RESUMO

Recent studies have revealed synaptic dysfunction to be a hallmark of various psychiatric diseases, and that glial cells participate in synapse formation, development, and plasticity. Glial cells contribute to neuroinflammation and synaptic homeostasis, the latter being essential for maintaining the physiological function of the central nervous system (CNS). In particular, glial cells undergo gliotransmission and regulate neuronal activity in tripartite synapses via ion channels (gap junction hemichannel, volume regulated anion channel, and bestrophin-1), receptors (for neurotransmitters and cytokines), or transporters (GLT-1, GLAST, and GATs) that are expressed on glial cell membranes. In this review, we propose that dysfunction in neuron-glia interactions may contribute to the pathogenesis of neurodevelopmental disorders. Understanding the mechanisms of neuron-glia interaction for synapse formation and maturation will contribute to the development of novel therapeutic targets of neurodevelopmental disorders.


Assuntos
Transtornos do Neurodesenvolvimento/genética , Neurogênese/genética , Neuroglia/metabolismo , Neurônios/metabolismo , Astrócitos/metabolismo , Astrócitos/patologia , Homeostase/genética , Humanos , Transtornos do Neurodesenvolvimento/patologia , Neuroglia/patologia , Neurônios/patologia
20.
Healthcare (Basel) ; 9(1)2020 Dec 23.
Artigo em Inglês | MEDLINE | ID: mdl-33374692

RESUMO

High-intensity exercise can lead to chronic fatigue, which reduces athletic performance. On the contrary, probiotic supplements have many health benefits, including improvement of gastrointestinal health and immunoregulation. However, the effects of probiotics combined with exercise interventions on motor functions and brain activity have not been fully explored. Therefore, this study aimed to identify the effects of probiotic supplements and aerobic exercise on motor function, immune response, and exercise intensity and probiotic ingestion. After four weeks of intervention, the motor functions were assessed by rotarod test, then the levels of cytokines, gamma-aminobutyric acid (GABA), and glutamate were detected. The improvement caused by the intake of probiotics in the moderate-intensity exercise group and the non-exercise group in the accelerating mode rotarod was significant (p = 0.038, p < 0.001, respectively). In constant-speed mode, the moderate-intensity exercise group with probiotic ingestion recorded longer runs than the corresponding non-exercise group (p = 0.023), and the improvement owing to probiotics was significant in all groups-non-exercise, moderate, and high-intensity (p = 0.036, p = 0.036, p = 0.012, respectively). The concentrations of inflammatory cytokines were lower, whereas GABA was higher in the probiotics-ingested group. Taken together, exercise and probiotics in adolescence could positively affect brain and motor function.

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