Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 58.929
Filtrar
1.
J Cell Mol Med ; 28(15): e18528, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-39099086

RESUMO

Huanglian Jiedu decoction (HLJD) has been used to treat ischemic stroke in clinic. However, the detailed protective mechanisms of HLJD on ischemic stroke have yet to be elucidated. The aim of this study is to elucidate the underlying pharmacological mechanisms of HLJD based on the inhibition of neuroinflammation and the amelioration of nerve cell damage. A middle cerebral artery occlusion reperfusion (MCAO/R) model was established in rats and received HLJD treatment. Effects of HLJD on neurological function was assessed based on Bederson's score, postural reflex test and asymmetry score. 2, 3, 5-Triphenyltetrazolium chloride (TTC) staining, Hematein and eosin (HE) and Nissl staining were used to observe the pathological changes in brain. Then, transcriptomics was used to screen the differential genes in brain tissue in MCAO/R model rats following HLJD intervention. Subsequently, the effects of HLJD on neutrophil extracellular trap (NET) formation-related neuroinflammation, gamma-aminobutyric acid (GABA)ergic synapse activation, nerve cell damage and proliferation were validated using immunofluorescence, western blot and enzyme-linked immunosorbent assay (ELISA). Our results showed that HLJD intervention reduced the Bederson's score, postural reflex test score and asymmetry score in MCAO/R model rats. Pathological staining indicated that HLJD treatment decreased the cerebral infarction area, mitigated neuronal damage and increased the numbers of Nissl bodies. Transcriptomics suggested that HLJD affected 435 genes in MCAO/R rats. Among them, several genes involving in NET formation and GABAergic synapses pathways were dysregulated. Subsequent experimental validation showed that HLJD reduced the MPO+CitH3+ positive expression area, reduced the protein expression of PAD4, p-P38/P38, p-ERK/ERK and decreased the levels of IL-1ß, IL-6 and TNF-α, reversed the increase of Iba1+TLR4+, Iba1+p65+ and Iba1+NLRP3+ positive expression area in brain. Moreover, HLJD increased GABA levels, elevated the protein expression of GABRG1 and GAT3, decreased the TUNEL positive expression area and increased the Ki67 positive expression area in brain. HLJD intervention exerts a multifaceted positive impact on ischemia-induced cerebral injury in MCAO/R rats. This intervention effectively inhibits neuroinflammation by mitigating NET formation, and concurrently improves nerve cell damage and fosters nerve cell proliferation through activating GABAergic synapses.


Assuntos
Isquemia Encefálica , Medicamentos de Ervas Chinesas , Ratos Sprague-Dawley , Sinapses , Animais , Medicamentos de Ervas Chinesas/farmacologia , Ratos , Masculino , Sinapses/efeitos dos fármacos , Sinapses/metabolismo , Isquemia Encefálica/metabolismo , Isquemia Encefálica/tratamento farmacológico , Modelos Animais de Doenças , Neurônios GABAérgicos/metabolismo , Neurônios GABAérgicos/efeitos dos fármacos , Ácido gama-Aminobutírico/metabolismo , Infarto da Artéria Cerebral Média/complicações , Traumatismo por Reperfusão/tratamento farmacológico , Traumatismo por Reperfusão/metabolismo , Traumatismo por Reperfusão/complicações , Fármacos Neuroprotetores/farmacologia , Encéfalo/patologia , Encéfalo/metabolismo , Encéfalo/efeitos dos fármacos
2.
Science ; 385(6710): 711-712, 2024 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-39146432

RESUMO

Patterns of spontaneous neuronal activity instruct the refinement of developing brain circuits.


Assuntos
Encéfalo , Plasticidade Neuronal , Sinapses , Animais , Sinapses/fisiologia , Encéfalo/citologia , Encéfalo/fisiologia , Encéfalo/crescimento & desenvolvimento , Neurônios/fisiologia , Neurônios/citologia , Camundongos
3.
J Vis Exp ; (209)2024 Jul 26.
Artigo em Inglês | MEDLINE | ID: mdl-39141541

RESUMO

The protocol describes single-neuron ablation with a 2-photon laser system in the central nervous system (CNS) of intact Drosophila melanogaster larvae. Using this non-invasive method, the developing nervous system can be manipulated in a cell-specific manner. Disrupting the development of individual neurons in a network can be used to study how the nervous system can compensate for the loss of synaptic input. Individual neurons were specifically ablated in the giant fiber system of Drosophila, with a focus on two neurons: the presynaptic giant fiber (GF) and the postsynaptic tergotrochanteral motor neuron (TTMn). The GF synapses with the ipsilateral TTMn, which is crucial to the escape response. Ablating one of the GFs in the 3rd instar brain, just after the GF starts axonal growth, permanently removes the cell during the development of the CNS. The remaining GF reacts to the absent neighbor and forms an ectopic synaptic terminal to the contralateral TTMn. This atypical, bilaterally symmetric terminal innervates both TTMns, as demonstrated by dye coupling, and drives both motor neurons, as demonstrated by electrophysiological assays. In summary, the ablation of a single interneuron demonstrates synaptic competition between a bilateral pair of neurons that can compensate for the loss of one neuron and restore normal responses to the escape circuit.


Assuntos
Drosophila melanogaster , Larva , Neurônios Motores , Sinapses , Animais , Sinapses/fisiologia , Neurônios Motores/citologia , Neurônios Motores/fisiologia , Terapia a Laser/métodos , Sistema Nervoso Central/citologia , Sistema Nervoso Central/fisiologia , Neurônios/citologia , Neurônios/fisiologia , Técnicas de Ablação/métodos
4.
Sci Adv ; 10(32): eadl5722, 2024 Aug 09.
Artigo em Inglês | MEDLINE | ID: mdl-39110798

RESUMO

Dendrite pathology and synaptic loss result in neural circuit dysfunction, a common feature of neurodegenerative diseases. There is a lack of strategies that target dendritic and synaptic regeneration to promote neurorecovery. We show that daily human recombinant insulin eye drops stimulate retinal ganglion cell (RGC) dendrite and synapse regeneration during ocular hypertension, a risk factor to develop glaucoma. We demonstrate that the ribosomal protein p70S6 kinase (S6K) is essential for insulin-dependent dendritic regrowth. Furthermore, S6K phosphorylation of the stress-activated protein kinase-interacting protein 1 (SIN1), a link between the mammalian target of rapamycin complexes 1 and 2 (mTORC1/2), is required for insulin-induced dendritic regeneration. Using two-photon microscopy live retinal imaging, we show that insulin rescues single-RGC light-evoked calcium (Ca2+) dynamics. We further demonstrate that insulin enhances neuronal survival and retina-brain connectivity leading to improved optomotor reflex-elicited behaviors. Our data support that insulin is a compelling pro-regenerative strategy with potential clinical implications for the treatment and management of glaucoma.


Assuntos
Glaucoma , Insulina , Células Ganglionares da Retina , Células Ganglionares da Retina/metabolismo , Células Ganglionares da Retina/efeitos dos fármacos , Glaucoma/tratamento farmacológico , Glaucoma/metabolismo , Glaucoma/patologia , Insulina/metabolismo , Insulina/farmacologia , Animais , Humanos , Camundongos , Modelos Animais de Doenças , Dendritos/metabolismo , Dendritos/efeitos dos fármacos , Sinapses/metabolismo , Sinapses/efeitos dos fármacos , Cálcio/metabolismo
5.
Sci Rep ; 14(1): 18226, 2024 08 06.
Artigo em Inglês | MEDLINE | ID: mdl-39107382

RESUMO

Theory predicts that nonlinear summation of synaptic potentials within dendrites allows neurons to perform linearly non-separable computations (LNSCs). Using Boolean analysis approaches, we predicted that both supralinear and sublinear synaptic summation could allow single neurons to implement a type of LNSC, the feature binding problem (FBP), which does not require inhibition contrary to the exclusive-or function (XOR). Notably, sublinear dendritic operations enable LNSCs when scattered synaptic activation generates increased somatic spike output. However, experimental demonstrations of scatter-sensitive neuronal computations have not yet been described. Using glutamate uncaging onto cerebellar molecular layer interneurons, we show that scattered synaptic-like activation of dendrites evoked larger compound EPSPs than clustered synaptic activation, generating a higher output spiking probability. Moreover, we also demonstrate that single interneurons can indeed implement the FBP. Using a biophysical model to explore the conditions in which a neuron might be expected to implement the FBP, we establish that sublinear summation is necessary but not sufficient. Other parameters such as the relative sublinearity, the EPSP size, depolarization amplitude relative to action potential threshold, and voltage fluctuations all influence whether the FBP can be performed. Since sublinear synaptic summation is a property of passive dendrites, we expect that many different neuron types can implement LNSCs.


Assuntos
Dendritos , Interneurônios , Modelos Neurológicos , Dendritos/fisiologia , Animais , Interneurônios/fisiologia , Potenciais de Ação/fisiologia , Potenciais Pós-Sinápticos Excitadores/fisiologia , Sinapses/fisiologia , Cerebelo/fisiologia , Cerebelo/citologia , Neurônios/fisiologia , Camundongos
6.
Cell Mol Biol Lett ; 29(1): 108, 2024 Aug 10.
Artigo em Inglês | MEDLINE | ID: mdl-39127627

RESUMO

Palmitoylation is a type of lipid modification that plays an important role in various aspects of neuronal function. Over the past few decades, several studies have shown that the palmitoylation of synaptic proteins is involved in neurotransmission and synaptic functions. Palmitoyl acyltransferases (PATs), which belong to the DHHC family, are major players in the regulation of palmitoylation. Dysregulated palmitoylation of synaptic proteins and mutated/dysregulated DHHC proteins are associated with several neurodegenerative diseases, such as Alzheimer's disease (AD), Huntington's disease (HD), and Parkinson's disease (PD). In this review, we summarize the recent discoveries on the subcellular distribution of DHHC proteins and analyze their expression patterns in different brain cells. In particular, this review discusses how palmitoylation of synaptic proteins regulates synaptic vesicle exocytotic fusion and the localization, clustering, and transport of several postsynaptic receptors, as well as the role of palmitoylation of other proteins in regulating synaptic proteins. Additionally, some of the specific known associations of these factors with neurodegenerative disorders are explored, with a few suggestions for the development of therapeutic strategies. Finally, this review provides possible directions for future research to reveal detailed and specific mechanisms underlying the roles of synaptic protein palmitoylation.


Assuntos
Lipoilação , Doenças Neurodegenerativas , Sinapses , Humanos , Doenças Neurodegenerativas/metabolismo , Animais , Sinapses/metabolismo , Aciltransferases/metabolismo , Proteínas do Tecido Nervoso/metabolismo , Proteínas do Tecido Nervoso/genética , Transmissão Sináptica
7.
J Neurosci ; 44(32)2024 Aug 07.
Artigo em Inglês | MEDLINE | ID: mdl-39111834

RESUMO

MicroRNAs are emerging as crucial regulators within the complex, dynamic environment of the synapse, and they offer a promising new avenue for the treatment of neurological disease. These small noncoding RNAs modify gene expression in several ways, including posttranscriptional modulation via binding to complementary and semicomplementary sites on target mRNAs. This rapid, finely tuned regulation of gene expression is essential to meet the dynamic demands of the synapse. Here, we provide a detailed review of the multifaceted world of synaptic microRNA regulation. We discuss the many mechanisms by which microRNAs regulate gene expression at the synapse, particularly in the context of neuronal plasticity. We also describe the various factors, such as age, sex, and neurological disease, that can influence microRNA expression and activity in neurons. In summary, microRNAs play a crucial role in the intricate and quickly changing functional requirements of the synapse, and context is essential in the study of microRNAs and their potential therapeutic applications.


Assuntos
Encéfalo , MicroRNAs , Plasticidade Neuronal , MicroRNAs/genética , MicroRNAs/metabolismo , Humanos , Animais , Encéfalo/metabolismo , Plasticidade Neuronal/fisiologia , Plasticidade Neuronal/genética , Sinapses/metabolismo , Sinapses/genética , Regulação da Expressão Gênica
8.
J Neuroinflammation ; 21(1): 200, 2024 Aug 11.
Artigo em Inglês | MEDLINE | ID: mdl-39129007

RESUMO

BACKGROUND: We recently reported that the dopamine (DA) analogue CA140 modulates neuroinflammatory responses in lipopolysaccharide-injected wild-type (WT) mice and in 3-month-old 5xFAD mice, a model of Alzheimer's disease (AD). However, the effects of CA140 on Aß/tau pathology and synaptic/cognitive function and its molecular mechanisms of action are unknown. METHODS: To investigate the effects of CA140 on cognitive and synaptic function and AD pathology, 3-month-old WT mice or 8-month-old (aged) 5xFAD mice were injected with vehicle (10% DMSO) or CA140 (30 mg/kg, i.p.) daily for 10, 14, or 17 days. Behavioral tests, ELISA, electrophysiology, RNA sequencing, real-time PCR, Golgi staining, immunofluorescence staining, and western blotting were conducted. RESULTS: In aged 5xFAD mice, a model of AD pathology, CA140 treatment significantly reduced Aß/tau fibrillation, Aß plaque number, tau hyperphosphorylation, and neuroinflammation by inhibiting NLRP3 activation. In addition, CA140 treatment downregulated the expression of cxcl10, a marker of AD-associated reactive astrocytes (RAs), and c1qa, a marker of the interaction of RAs with disease-associated microglia (DAMs) in 5xFAD mice. CA140 treatment also suppressed the mRNA levels of s100ß and cxcl10, markers of AD-associated RAs, in primary astrocytes from 5xFAD mice. In primary microglial cells from 5xFAD mice, CA140 treatment increased the mRNA levels of markers of homeostatic microglia (cx3cr1 and p2ry12) and decreased the mRNA levels of a marker of proliferative region-associated microglia (gpnmb) and a marker of lipid-droplet-accumulating microglia (cln3). Importantly, CA140 treatment rescued scopolamine (SCO)-mediated deficits in long-term memory, dendritic spine number, and LTP impairment. In aged 5xFAD mice, these effects of CA140 treatment on cognitive/synaptic function and AD pathology were regulated by dopamine D1 receptor (DRD1)/Elk1 signaling. In primary hippocampal neurons and WT mice, CA140 treatment promoted long-term memory and dendritic spine formation via effects on DRD1/CaMKIIα and/or ERK signaling. CONCLUSIONS: Our results indicate that CA140 improves neuronal/synaptic/cognitive function and ameliorates Aß/tau pathology and neuroinflammation by modulating DRD1 signaling in primary hippocampal neurons, primary astrocytes/microglia, WT mice, and aged 5xFAD mice.


Assuntos
Doença de Alzheimer , Peptídeos beta-Amiloides , Camundongos Transgênicos , Doenças Neuroinflamatórias , Receptores de Dopamina D1 , Transdução de Sinais , Animais , Doença de Alzheimer/tratamento farmacológico , Doença de Alzheimer/metabolismo , Doença de Alzheimer/patologia , Camundongos , Peptídeos beta-Amiloides/metabolismo , Doenças Neuroinflamatórias/tratamento farmacológico , Doenças Neuroinflamatórias/metabolismo , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/fisiologia , Receptores de Dopamina D1/metabolismo , Sinapses/efeitos dos fármacos , Sinapses/metabolismo , Sinapses/patologia , Cognição/efeitos dos fármacos , Dopamina/metabolismo , Camundongos Endogâmicos C57BL , Masculino , Humanos
9.
Nat Commun ; 15(1): 6842, 2024 Aug 09.
Artigo em Inglês | MEDLINE | ID: mdl-39122700

RESUMO

Astrocytes control brain activity via both metabolic processes and gliotransmission, but the physiological links between these functions are scantly known. Here we show that endogenous activation of astrocyte type-1 cannabinoid (CB1) receptors determines a shift of glycolysis towards the lactate-dependent production of D-serine, thereby gating synaptic and cognitive functions in male mice. Mutant mice lacking the CB1 receptor gene in astrocytes (GFAP-CB1-KO) are impaired in novel object recognition (NOR) memory. This phenotype is rescued by the gliotransmitter D-serine, by its precursor L-serine, and also by lactate and 3,5-DHBA, an agonist of the lactate receptor HCAR1. Such lactate-dependent effect is abolished when the astrocyte-specific phosphorylated-pathway (PP), which diverts glycolysis towards L-serine synthesis, is blocked. Consistently, lactate and 3,5-DHBA promoted the co-agonist binding site occupancy of CA1 post-synaptic NMDA receptors in hippocampal slices in a PP-dependent manner. Thus, a tight cross-talk between astrocytic energy metabolism and gliotransmission determines synaptic and cognitive processes.


Assuntos
Astrócitos , Cognição , Glicólise , Ácido Láctico , Camundongos Knockout , Serina , Animais , Masculino , Astrócitos/metabolismo , Cognição/fisiologia , Camundongos , Ácido Láctico/metabolismo , Serina/metabolismo , Receptores de N-Metil-D-Aspartato/metabolismo , Receptores de N-Metil-D-Aspartato/genética , Hipocampo/metabolismo , Sinapses/metabolismo , Camundongos Endogâmicos C57BL , Receptores Acoplados a Proteínas G/metabolismo , Receptores Acoplados a Proteínas G/genética
10.
J Cell Biol ; 223(9)2024 Sep 02.
Artigo em Inglês | MEDLINE | ID: mdl-39136998

RESUMO

Extracellular vesicles are known for intercellular signaling roles but can also serve to simply dispose of unwanted cargoes. In this issue, Bostelman and Broihier discuss new work from Rodal and colleagues (https://doi.org/10.1083/jcb.202405025) that refutes prior work by showing that extracellular vesicles at Drosophila neuromuscular junctions are not required for signaling and instead likely serve a proteostasis role.


Assuntos
Vesículas Extracelulares , Junção Neuromuscular , Animais , Vesículas Extracelulares/metabolismo , Junção Neuromuscular/metabolismo , Transdução de Sinais , Sinapses/metabolismo , Drosophila melanogaster/metabolismo , Proteínas de Drosophila/metabolismo , Proteínas de Drosophila/genética , Drosophila/metabolismo , Comunicação Celular , Proteostase
11.
Sci Adv ; 10(31): eadk4331, 2024 Aug 02.
Artigo em Inglês | MEDLINE | ID: mdl-39093969

RESUMO

Homeostatic plasticity maintains the stability of functional brain networks. The axon initial segment (AIS), where action potentials start, undergoes dynamic adjustment to exert powerful control over neuronal firing properties in response to network activity changes. However, it is poorly understood whether this plasticity involves direct synaptic input to the AIS. Here, we show that changes of GABAergic synaptic input from chandelier cells (ChCs) drive homeostatic tuning of the AIS of principal neurons (PNs) in the prelimbic (PL) region, while those from parvalbumin-positive basket cells do not. This tuning is evident in AIS morphology, voltage-gated sodium channel expression, and PN excitability. Moreover, the impact of this homeostatic plasticity can be reflected in animal behavior. Social behavior, inversely linked to PL PN activity, shows time-dependent alterations tightly coupled to changes in AIS plasticity and PN excitability. Thus, AIS-originated homeostatic plasticity in PNs may counteract deficits elicited by imbalanced ChC presynaptic input at cellular and behavioral levels.


Assuntos
Segmento Inicial do Axônio , Axônios , Homeostase , Plasticidade Neuronal , Sinapses , Animais , Plasticidade Neuronal/fisiologia , Segmento Inicial do Axônio/metabolismo , Axônios/fisiologia , Axônios/metabolismo , Camundongos , Sinapses/fisiologia , Potenciais de Ação , Masculino , Neurônios GABAérgicos/fisiologia , Neurônios GABAérgicos/metabolismo
12.
J Neuroinflammation ; 21(1): 192, 2024 Aug 02.
Artigo em Inglês | MEDLINE | ID: mdl-39095838

RESUMO

BACKGROUND: Type 2 diabetes mellitus (T2D) is associated with an increased risk of cognitive dysfunction. Angiopoietin-like protein 8 (ANGPTL8) is an important regulator in T2D, but the role of ANGPTL8 in diabetes-associated cognitive dysfunction remains unknown. Here, we explored the role of ANGPTL8 in diabetes-associated cognitive dysfunction through its interaction with paired immunoglobulin-like receptor B (PirB) in the central nervous system. METHODS: The levels of ANGPTL8 in type 2 diabetic patients with cognitive dysfunction and control individuals were measured. Mouse models of diabetes-associated cognitive dysfunction were constructed to investigate the role of ANGPTL8 in cognitive function. The cognitive function of the mice was assessed by the Barnes Maze test and the novel object recognition test, and levels of ANGPTL8, synaptic and axonal markers, and pro-inflammatory cytokines were measured. Primary neurons and microglia were treated with recombinant ANGPTL8 protein (rA8), and subsequent changes were examined. In addition, the changes induced by ANGPTL8 were validated after blocking PirB and its downstream pathways. Finally, mice with central nervous system-specific knockout of Angptl8 and PirB-/- mice were generated, and relevant in vivo experiments were performed. RESULTS: Here, we demonstrated that in the diabetic brain, ANGPTL8 was secreted by neurons into the hippocampus, resulting in neuroinflammation and impairment of synaptic plasticity. Moreover, neuron-specific Angptl8 knockout prevented diabetes-associated cognitive dysfunction and neuroinflammation. Mechanistically, ANGPTL8 acted in parallel to neurons and microglia via its receptor PirB, manifesting as downregulation of synaptic and axonal markers in neurons and upregulation of proinflammatory cytokine expression in microglia. In vivo, PirB-/- mice exhibited resistance to ANGPTL8-induced neuroinflammation and synaptic damage. CONCLUSION: Taken together, our findings reveal the role of ANGPTL8 in the pathogenesis of diabetes-associated cognitive dysfunction and identify the ANGPTL8-PirB signaling pathway as a potential target for the management of this condition.


Assuntos
Proteína 8 Semelhante a Angiopoietina , Proteínas Semelhantes a Angiopoietina , Disfunção Cognitiva , Diabetes Mellitus Tipo 2 , Camundongos Knockout , Receptores Imunológicos , Transdução de Sinais , Animais , Camundongos , Disfunção Cognitiva/metabolismo , Disfunção Cognitiva/prevenção & controle , Disfunção Cognitiva/etiologia , Transdução de Sinais/fisiologia , Transdução de Sinais/efeitos dos fármacos , Proteínas Semelhantes a Angiopoietina/metabolismo , Proteínas Semelhantes a Angiopoietina/genética , Humanos , Masculino , Diabetes Mellitus Tipo 2/complicações , Diabetes Mellitus Tipo 2/metabolismo , Receptores Imunológicos/metabolismo , Receptores Imunológicos/genética , Camundongos Endogâmicos C57BL , Sinapses/metabolismo , Sinapses/patologia , Sinapses/efeitos dos fármacos , Hormônios Peptídicos/metabolismo , Pessoa de Meia-Idade , Feminino
13.
CNS Neurosci Ther ; 30(8): e14897, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-39097920

RESUMO

Synaptic plasticity is believed to underlie the cellular and molecular basis of memory formation. Mitochondria are one of the main organelles involved in metabolism and energy maintenance as plastic organelles that change morphologically and functionally in response to cellular needs and regulate synaptic function and plasticity through multiple mechanisms, including ATP generation, calcium homeostasis, and biogenesis. An increased neuronal activity enhances synaptic efficiency, during which mitochondria's spatial distribution and morphology change significantly. These organelles build up in the pre-and postsynaptic zones to produce ATP, which is necessary for several synaptic processes like neurotransmitter release and recycling. Mitochondria also regulate calcium homeostasis by buffering intracellular calcium, which ensures proper synaptic activity. Furthermore, mitochondria in the presynaptic terminal have distinct morphological properties compared to dendritic or postsynaptic mitochondria. This specialization enables precise control of synaptic activity and plasticity. Mitochondrial dysfunction has been linked to synaptic failure in many neurodegenerative disorders, like Alzheimer's disease (AD). In AD, malfunctioning mitochondria cause delays in synaptic vesicle release and recycling, ionic gradient imbalances, and mostly synaptic failure. This review emphasizes mitochondrial plasticity's contribution to synaptic function. It also explores the profound effect of mitochondrial malfunction on neurodegenerative disorders, focusing on AD, and provides an overview of how they sustain cellular health under normal conditions and how their malfunction contributes to neurodegenerative diseases, highlighting their potential as a therapeutic target for such conditions.


Assuntos
Doença de Alzheimer , Mitocôndrias , Plasticidade Neuronal , Humanos , Plasticidade Neuronal/fisiologia , Doença de Alzheimer/metabolismo , Doença de Alzheimer/patologia , Doença de Alzheimer/fisiopatologia , Mitocôndrias/metabolismo , Animais , Sinapses/fisiologia , Sinapses/patologia , Sinapses/metabolismo
14.
Cells ; 13(15)2024 Jul 23.
Artigo em Inglês | MEDLINE | ID: mdl-39120267

RESUMO

The melanocortin-4 receptor (MC4R) is a G protein-coupled receptor (GPCR) that is expressed in several brain locations encompassing the hypothalamus and the brainstem, where the receptor controls several body functions, including metabolism. In a well-defined pathway to decrease appetite, hypothalamic proopiomelanocortin (POMC) neurons localized in the arcuate nucleus (Arc) project to MC4R neurons in the paraventricular nuclei (PVN) to release the natural MC4R agonist α-melanocyte-stimulating hormone (α-MSH). Arc neurons also project excitatory glutamatergic fibers to the MC4R neurons in the PVN for a fast synaptic transmission to regulate a satiety pathway potentiated by α-MSH. By using super-resolution microscopy, we found that in hypothalamic neurons in a primary culture, postsynaptic density protein 95 (PSD95) colocalizes with GluN1, a subunit of the ionotropic N-methyl-D-aspartate receptor (NMDAR). Thus, hypothalamic neurons form excitatory postsynaptic specializations. To study the MC4R distribution at these sites, tagged HA-MC4R under the synapsin promoter was expressed in neurons by adeno-associated virus (AAV) gene transduction. HA-MC4R immunofluorescence peaked at the center and in proximity to the PSD95- and NMDAR-expressing sites. These data provide morphological evidence that MC4R localizes together with glutamate receptors at postsynaptic and peri-postsynaptic sites.


Assuntos
Hipotálamo , Neurônios , Receptor Tipo 4 de Melanocortina , Animais , Receptor Tipo 4 de Melanocortina/metabolismo , Receptor Tipo 4 de Melanocortina/genética , Neurônios/metabolismo , Hipotálamo/metabolismo , Hipotálamo/citologia , Camundongos , Sinapses/metabolismo , Proteína 4 Homóloga a Disks-Large/metabolismo , Células Cultivadas , Receptores de N-Metil-D-Aspartato/metabolismo
15.
Cells ; 13(15)2024 Aug 03.
Artigo em Inglês | MEDLINE | ID: mdl-39120329

RESUMO

The pathogenic expansion of the intronic GGGGCC hexanucleotide located in the non-coding region of the C9orf72 gene represents the most frequent genetic cause of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). This mutation leads to the accumulation of toxic RNA foci and dipeptide repeats (DPRs), as well as reduced levels of the C9orf72 protein. Thus, both gain and loss of function are coexisting pathogenic aspects linked to C9orf72-ALS/FTD. Synaptic alterations have been largely described in C9orf72 models, but it is still not clear which aspect of the pathology mostly contributes to these impairments. To address this question, we investigated the dynamic changes occurring over time at the synapse upon accumulation of poly(GA), the most abundant DPR. Overexpression of this toxic form induced a drastic loss of synaptic proteins in primary neuron cultures, anticipating autophagic defects. Surprisingly, the dramatic impairment characterizing the synaptic proteome was not fully matched by changes in network properties. In fact, high-density multi-electrode array analysis highlighted only minor reductions in the spike number and firing rate of poly(GA) neurons. Our data show that the toxic gain of function linked to C9orf72 affects the synaptic proteome but exerts only minor effects on the network activity.


Assuntos
Autofagia , Proteína C9orf72 , Neurônios , Sinapses , Neurônios/metabolismo , Animais , Sinapses/metabolismo , Proteína C9orf72/genética , Proteína C9orf72/metabolismo , Células Cultivadas , Peptídeos/metabolismo , Humanos , Agregados Proteicos
16.
Cell Mol Life Sci ; 81(1): 342, 2024 Aug 09.
Artigo em Inglês | MEDLINE | ID: mdl-39123091

RESUMO

A Disintegrin And Metalloproteinase 10 (ADAM10) plays a pivotal role in shaping neuronal networks by orchestrating the activity of numerous membrane proteins through the shedding of their extracellular domains. Despite its significance in the brain, the specific cellular localization of ADAM10 remains not well understood due to a lack of appropriate tools. Here, using a specific ADAM10 antibody suitable for immunostainings, we observed that ADAM10 is localized to presynapses and especially enriched at presynaptic vesicles of mossy fiber (MF)-CA3 synapses in the hippocampus. These synapses undergo pronounced frequency facilitation of neurotransmitter release, a process that play critical roles in information transfer and neural computation. We demonstrate, that in conditional ADAM10 knockout mice the ability of MF synapses to undergo this type of synaptic plasticity is greatly reduced. The loss of facilitation depends on the cytosolic domain of ADAM10 and association with the calcium sensor synaptotagmin 7 rather than ADAM10's proteolytic activity. Our findings unveil a new role of ADAM10 in the regulation of synaptic vesicle exocytosis.


Assuntos
Proteína ADAM10 , Secretases da Proteína Precursora do Amiloide , Proteínas de Membrana , Camundongos Knockout , Plasticidade Neuronal , Vesículas Sinápticas , Animais , Proteína ADAM10/metabolismo , Proteína ADAM10/genética , Plasticidade Neuronal/fisiologia , Secretases da Proteína Precursora do Amiloide/metabolismo , Secretases da Proteína Precursora do Amiloide/genética , Proteínas de Membrana/metabolismo , Proteínas de Membrana/genética , Camundongos , Vesículas Sinápticas/metabolismo , Camundongos Endogâmicos C57BL , Sinapses/metabolismo , Fibras Musgosas Hipocampais/metabolismo , Hipocampo/metabolismo , Exocitose/fisiologia , Terminações Pré-Sinápticas/metabolismo , Transmissão Sináptica , Sinaptotagminas/metabolismo , Sinaptotagminas/genética
17.
Elife ; 122024 Aug 06.
Artigo em Inglês | MEDLINE | ID: mdl-39106188

RESUMO

Biological synaptic transmission is unreliable, and this unreliability likely degrades neural circuit performance. While there are biophysical mechanisms that can increase reliability, for instance by increasing vesicle release probability, these mechanisms cost energy. We examined four such mechanisms along with the associated scaling of the energetic costs. We then embedded these energetic costs for reliability in artificial neural networks (ANNs) with trainable stochastic synapses, and trained these networks on standard image classification tasks. The resulting networks revealed a tradeoff between circuit performance and the energetic cost of synaptic reliability. Additionally, the optimised networks exhibited two testable predictions consistent with pre-existing experimental data. Specifically, synapses with lower variability tended to have (1) higher input firing rates and (2) lower learning rates. Surprisingly, these predictions also arise when synapse statistics are inferred through Bayesian inference. Indeed, we were able to find a formal, theoretical link between the performance-reliability cost tradeoff and Bayesian inference. This connection suggests two incompatible possibilities: evolution may have chanced upon a scheme for implementing Bayesian inference by optimising energy efficiency, or alternatively, energy-efficient synapses may display signatures of Bayesian inference without actually using Bayes to reason about uncertainty.


Assuntos
Teorema de Bayes , Redes Neurais de Computação , Sinapses , Sinapses/fisiologia , Modelos Neurológicos , Transmissão Sináptica/fisiologia , Metabolismo Energético , Animais , Neurônios/fisiologia
18.
Cereb Cortex ; 34(8)2024 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-39106175

RESUMO

Functional and structural studies investigating macroscopic connectivity in the human cerebral cortex suggest that high-order associative regions exhibit greater connectivity compared to primary ones. However, the synaptic organization of these brain regions remains unexplored. In the present work, we conducted volume electron microscopy to investigate the synaptic organization of the human brain obtained at autopsy. Specifically, we examined layer III of Brodmann areas 17, 3b, and 4, as representative areas of primary visual, somatosensorial, and motor cortex. Additionally, we conducted comparative analyses with our previous datasets of layer III from temporopolar and anterior cingulate associative cortical regions (Brodmann areas 24, 38, and 21). 9,690 synaptic junctions were 3D reconstructed, showing that certain synaptic characteristics are specific to particular regions. The number of synapses per volume, the proportion of the postsynaptic targets, and the synaptic size may distinguish one region from another, regardless of whether they are associative or primary cortex. By contrast, other synaptic characteristics were common to all analyzed regions, such as the proportion of excitatory and inhibitory synapses, their shapes, their spatial distribution, and a higher proportion of synapses located on dendritic spines. The present results provide further insights into the synaptic organization of the human cerebral cortex.


Assuntos
Córtex Cerebral , Sinapses , Microscopia Eletrônica de Volume , Adulto , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Córtex Cerebral/ultraestrutura , Espinhas Dendríticas/ultraestrutura , Imageamento Tridimensional/métodos , Sinapses/ultraestrutura
19.
Nat Commun ; 15(1): 6683, 2024 Aug 06.
Artigo em Inglês | MEDLINE | ID: mdl-39107293

RESUMO

Focal cortical dysplasia type I (FCD I) is the most common cause of pharmaco-resistant epilepsy with the poorest prognosis. To understand the epileptogenic mechanisms of FCD I, we obtained tissue resected from patients with FCD I epilepsy, and from tumor patients as control. Using whole-cell patch clamp in acute human brain slices, we investigated the cellular properties of fast-spiking interneurons (FSINs) and pyramidal neurons (PNs) within the ictal onset zone. In FCD I epilepsy, FSINs exhibited lower firing rates from slower repolarization and action potential broadening, while PNs had increased firing. Importantly, excitatory synaptic drive of FSINs increased progressively with the scale of cortical activation as a general property across species, but this relationship was inverted towards net inhibition in FCD I epilepsy. Further comparison with intracranial electroencephalography (iEEG) from the same patients revealed that the spatial extent of pathological high-frequency oscillations (pHFO) was associated with synaptic events at FSINs.


Assuntos
Potenciais de Ação , Epilepsia , Interneurônios , Células Piramidais , Humanos , Interneurônios/fisiologia , Feminino , Masculino , Células Piramidais/fisiologia , Potenciais de Ação/fisiologia , Epilepsia/fisiopatologia , Adulto , Malformações do Desenvolvimento Cortical/fisiopatologia , Adolescente , Adulto Jovem , Criança , Técnicas de Patch-Clamp , Sinapses/fisiologia , Pré-Escolar , Epilepsia Resistente a Medicamentos/fisiopatologia , Epilepsia Resistente a Medicamentos/cirurgia , Eletrocorticografia
20.
Sci Rep ; 14(1): 18002, 2024 08 03.
Artigo em Inglês | MEDLINE | ID: mdl-39097642

RESUMO

Zika virus (ZIKV) infection was first reported in 2015 in Brazil as causing microcephaly and other developmental abnormalities in newborns, leading to the identification of Congenital Zika Syndrome (CZS). Viral infections have been considered an environmental risk factor for neurodevelopmental disorders outcome, such as Autism Spectrum Disorder (ASD). Moreover, not only the infection per se, but maternal immune system activation during pregnancy, has been linked to fetal neurodevelopmental disorders. To understand the impact of ZIKV vertical infection on brain development, we derived induced pluripotent stem cells (iPSC) from Brazilian children born with CZS, some of the patients also being diagnosed with ASD. Comparing iPSC-derived neurons from CZS with a control group, we found lower levels of pre- and postsynaptic proteins and reduced functional synapses by puncta co-localization. Furthermore, neurons and astrocytes derived from the CZS group showed decreased glutamate levels. Additionally, the CZS group exhibited elevated levels of cytokine production, one of which being IL-6, already associated with the ASD phenotype. These preliminary findings suggest that ZIKV vertical infection may cause long-lasting disruptions in brain development during fetal stages, even in the absence of the virus after birth. These disruptions could contribute to neurodevelopmental disorders manifestations such as ASD. Our study contributes with novel knowledge of the CZS outcomes and paves the way for clinical validation and the development of potential interventions to mitigate the impact of ZIKV vertical infection on neurodevelopment.


Assuntos
Encéfalo , Células-Tronco Pluripotentes Induzidas , Transmissão Vertical de Doenças Infecciosas , Sinapses , Infecção por Zika virus , Zika virus , Humanos , Infecção por Zika virus/virologia , Infecção por Zika virus/patologia , Feminino , Zika virus/patogenicidade , Sinapses/patologia , Sinapses/metabolismo , Encéfalo/virologia , Encéfalo/patologia , Gravidez , Células-Tronco Pluripotentes Induzidas/metabolismo , Células-Tronco Pluripotentes Induzidas/virologia , Neurônios/virologia , Neurônios/metabolismo , Neurônios/patologia , Masculino , Astrócitos/virologia , Astrócitos/metabolismo , Doenças Neuroinflamatórias/virologia , Doenças Neuroinflamatórias/patologia , Doenças Neuroinflamatórias/metabolismo , Complicações Infecciosas na Gravidez/virologia , Complicações Infecciosas na Gravidez/patologia , Brasil , Recém-Nascido , Transtorno do Espectro Autista/virologia , Criança
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA