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1.
Phys Chem Chem Phys ; 23(31): 16718-16729, 2021 Aug 12.
Artigo em Inglês | MEDLINE | ID: mdl-34318818

RESUMO

Synapsin I (SynI) is the most abundant brain phosphoprotein present at presynaptic terminals that regulates neurotransmitter release, clustering of synaptic vesicles (SVs) at active zones, and stimulates synaptogenesis and neurite outgrowth. Earlier studies have established that SynI displays pH-dependent tethering of SVs to actin filaments and exhibits a maximum binding around neutral pH, however, the effect of pH shift from acidic to basic on the conformational stability of SynI has not been explored yet. Another important aspect of SynIa is its O-GlcNAcylation (O-GlcNac) at the Thr87 position, which is responsible for the positive regulation of synaptic plasticity linked to learning and memory in mice. Furthermore, reduced levels of O-GlcNAc have been observed in Alzheimer's disease, suggesting a possible link to deficits in synaptic plasticity. In this study, the effect of pH and glycosylation on the structure and functional stability of SynIa is determined through molecular dynamics (MD) simulation approach. The 3D structure of SynIa was established via threading-based homology modeling methods. It was observed that the structure of SynIa adopts extended conformational changes as the pH shifts from acidic to basic, resulting in a compact conformation at pH 8.0. Moreover, the results obtained by comparing the glycosylated and unglycosylated protein indicated that the glycan moiety imparts stability to the protein by forming intramolecular hydrogen bond interactions with the protein residues. The results indicate that although O-GlcNAc moieties do not induce a significant change in SynIa structure they minimize protein dynamics, likely leading to enhanced protein stability.


Assuntos
Prótons , Sinapsinas/química , Glicosilação , Humanos , Concentração de Íons de Hidrogênio , Modelos Moleculares , Conformação Proteica , Sinapsinas/metabolismo
2.
Neurology ; 97(6): e577-e586, 2021 08 10.
Artigo em Inglês | MEDLINE | ID: mdl-34078716

RESUMO

OBJECTIVE: To describe the clinical and genetic findings in a cohort of individuals with bathing epilepsy, a rare form of reflex epilepsy. METHODS: We investigated by Sanger and targeted resequencing the SYN1 gene in 12 individuals from 10 different families presenting with seizures triggered primarily by bathing or showering. An additional 12 individuals with hot-water epilepsy were also screened. RESULTS: In all families with bathing epilepsy, we identified 8 distinct pathogenic or likely pathogenic variants and 2 variants of unknown significance in SYN1, 9 of which are novel. Conversely, none of the individuals with hot-water epilepsy displayed SYN1 variants. In mutated individuals, seizures were typically triggered by showering or bathing regardless of the water temperature. Additional triggers included fingernail clipping, haircutting, or watching someone take a shower. Unprovoked seizures and a variable degree of developmental delay were also common. CONCLUSION: Bathing epilepsy is genetically distinct reflex epilepsy caused mainly by SYN1 mutations.


Assuntos
Banhos , Epilepsia Reflexa/genética , Epilepsia Reflexa/fisiopatologia , Higiene , Sinapsinas/genética , Adolescente , Criança , Pré-Escolar , Feminino , Temperatura Alta , Humanos , Masculino , Pessoa de Meia-Idade , Linhagem , Água
3.
Neurochem Res ; 46(6): 1577-1588, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-33791908

RESUMO

General anesthetics (GAs) may cause disruptions in brain development, and the effect of GA exposure in the setting of pre-existing neurodevelopmental disease is unknown. We tested the hypothesis that synaptic development is more vulnerable to GA-induced deficits in a mouse model of fragile X syndrome than in WT mice and asked whether they were related to the mTOR pathway, a signaling system implicated in both anesthesia toxicity and fragile X syndrome. Early postnatal WT and Fmr1-KO mice were exposed to isoflurane and brain slices were collected in adulthood. Primary neuron cultures isolated from WT and Fmr1-KO mice were exposed to isoflurane during development, in some cases treated with rapamycin, and processed for immunohistochemistry at maturity. Quantitative immunofluorescence microscopy was conducted for synaptic markers and markers of mTOR pathway activity. Isoflurane exposure caused reduction in Synpasin-1, PSD-95, and Gephyrin puncta that was significantly lower in Fmr1-KO mice than in WT mice. Similar results were found in cell culture, where synapse loss was ameliorated with rapamycin treatment. Early developmental exposure to isoflurane causes more profound synapse loss in Fmr1- KO than WT mice, and this effect is mediated by a pathologic increase in mTOR pathway activity.


Assuntos
Anestésicos Inalatórios/farmacologia , Proteína do X Frágil de Retardo Mental/metabolismo , Isoflurano/farmacologia , Transdução de Sinais/efeitos dos fármacos , Sinapses/efeitos dos fármacos , Serina-Treonina Quinases TOR/metabolismo , Animais , Proteína 4 Homóloga a Disks-Large/metabolismo , Feminino , Proteína do X Frágil de Retardo Mental/genética , Masculino , Proteínas de Membrana/metabolismo , Camundongos Endogâmicos C57BL , Camundongos Knockout , Neurônios/efeitos dos fármacos , Neurônios/metabolismo , Gravidez , Sirolimo/farmacologia , Sinapses/metabolismo , Sinapsinas/metabolismo
4.
Chem Biol Interact ; 341: 109454, 2021 May 25.
Artigo em Inglês | MEDLINE | ID: mdl-33798505

RESUMO

Doxycycline has been used as antibiotic since the 1960s. Recently, studies have shown that doxycycline is neuroprotective in models of neurodegenerative diseases and brain injuries, mainly due to anti-inflammatory and anti-apoptotic effects. However, it is not known if doxycycline has neurotrophic potential, which is relevant, considering the role of axonal degeneration at the early stages of neurodegeneration in Alzheimer's disease, Amyotrophic Lateral Sclerosis and Parkinson's disease as well as in normal aging. Axons are preceded by the formation of neurites, the hallmark of the neuronal differentiation induced by neurotrophins like NGF. Therefore, the modulation of neurotrophin receptors aimed at formation and regeneration of axons has been proposed as a strategy to delay the progression of neurodegeneration and has gained relevance as new techniques for early diagnosis arise. Based on these premises, we investigated the potential of doxycycline to mimic the effects of Nerve Growth Factor (NGF) with focus on the signaling pathways and neuronal modulators of neurite initiation, growth and branching. We used PC12 cells, a neuronal model widely employed to study the neurotrophic pathways and mechanisms induced by NGF. Results showed that doxycycline induced neurite outgrowth via activation of the trkA receptor and the downstream signaling pathways, PI3K/Akt and MAPK/ERK, without inducing the expression of NGF. Doxycycline also increased the expression of GAP-43, synapsin I and NF200, proteins involved in axonal and synaptic plasticity. Altogether, these data demonstrate, for the first time, the neurotrophic potential of doxycycline, which might be useful to restore the neuronal connectivity lost at the initial phase of neurodegeneration.


Assuntos
Antibacterianos/farmacologia , Doxiciclina/farmacologia , Fator de Crescimento Neural/metabolismo , Animais , Carbazóis/farmacologia , Sobrevivência Celular/efeitos dos fármacos , Proteína GAP-43/metabolismo , Alcaloides Indólicos/farmacologia , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Fator de Crescimento Neural/farmacologia , Proteínas de Neurofilamentos/metabolismo , Crescimento Neuronal/efeitos dos fármacos , Fármacos Neuroprotetores/farmacologia , Células PC12 , Fosfatidilinositol 3-Quinases/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Ratos , Receptor trkA/antagonistas & inibidores , Receptor trkA/metabolismo , Transdução de Sinais/efeitos dos fármacos , Sinapsinas/metabolismo
5.
Cell Mol Life Sci ; 78(11): 4973-4992, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-33864480

RESUMO

Amyloid beta (Aß) is linked to the pathology of Alzheimer's disease (AD). At physiological concentrations, Aß was proposed to enhance neuroplasticity and memory formation by increasing the neurotransmitter release from presynapse. However, the exact mechanisms underlying this presynaptic effect as well as specific contribution of endogenously occurring Aß isoforms remain unclear. Here, we demonstrate that Aß1-42 and Aß1-16, but not Aß17-42, increased size of the recycling pool of synaptic vesicles (SV). This presynaptic effect was driven by enhancement of endogenous cholinergic signalling via α7 nicotinic acetylcholine receptors, which led to activation of calcineurin, dephosphorylation of synapsin 1 and consequently resulted in reorganization of functional pools of SV increasing their availability for sustained neurotransmission. Our results identify synapsin 1 as a molecular target of Aß and reveal an effect of physiological concentrations of Aß on cholinergic modulation of glutamatergic neurotransmission. These findings provide new mechanistic insights in cholinergic dysfunction observed in AD.


Assuntos
Peptídeos beta-Amiloides/farmacologia , Fragmentos de Peptídeos/farmacologia , Sinapses/metabolismo , Sinapsinas/metabolismo , Vesículas Sinápticas/efeitos dos fármacos , Receptor Nicotínico de Acetilcolina alfa7/metabolismo , Animais , Cálcio/metabolismo , Potenciais Pós-Sinápticos Excitadores/efeitos dos fármacos , Feminino , Humanos , Camundongos , Camundongos Knockout , Neurônios/citologia , Neurônios/efeitos dos fármacos , Neurônios/metabolismo , Neurotransmissores/metabolismo , Nicotina/farmacologia , Fosforilação/efeitos dos fármacos , Ratos , Ratos Sprague-Dawley , Vesículas Sinápticas/fisiologia , Receptor Nicotínico de Acetilcolina alfa7/deficiência , Receptor Nicotínico de Acetilcolina alfa7/genética
6.
J Mol Biol ; 433(12): 166961, 2021 06 11.
Artigo em Inglês | MEDLINE | ID: mdl-33774037

RESUMO

Neurotransmission relies on the tight spatial and temporal regulation of the synaptic vesicle (SV) cycle. Nerve terminals contain hundreds of SVs that form tight clusters. These clusters represent a distinct liquid phase in which one component of the phase are SVs and the other synapsin 1, a highly abundant synaptic protein. Another major family of disordered proteins at the presynapse includes synucleins, most notably α-synuclein. The precise physiological role of α-synuclein in synaptic physiology remains elusive, albeit its role has been implicated in nearly all steps of the SV cycle. To determine the effect of α-synuclein on the synapsin phase, we employ the reconstitution approach using natively purified SVs from rat brains and the heterologous cell system to generate synapsin condensates. We demonstrate that synapsin condensates recruit α-synuclein, and while enriched into these synapsin condensates, α-synuclein still maintains its high mobility. The presence of SVs enhances the rate of synapsin/α-synuclein condensation, suggesting that SVs act as catalyzers for the formation of synapsin condensates. Notably, at physiological salt and protein concentrations, α-synuclein alone is not able to cluster isolated SVs. Excess of α-synuclein disrupts the kinetics of synapsin/SV condensate formation, indicating that the molar ratio between synapsin and α-synuclein is important in assembling the functional condensates of SVs. Understanding the molecular mechanism of α-synuclein interactions at the nerve terminals is crucial for clarifying the pathogenesis of synucleinopathies, where α-synuclein, synaptic proteins and lipid organelles all accumulate as insoluble intracellular inclusions.


Assuntos
Encéfalo/citologia , Sinapsinas/metabolismo , Vesículas Sinápticas/metabolismo , alfa-Sinucleína/metabolismo , Animais , Encéfalo/metabolismo , Células HEK293 , Humanos , Proteínas Luminescentes/genética , Proteínas Luminescentes/metabolismo , Substâncias Macromoleculares/química , Substâncias Macromoleculares/metabolismo , Microscopia Confocal , Microscopia de Fluorescência , Ratos , Sinapsinas/química , Transmissão Sináptica , alfa-Sinucleína/química
7.
J Neurosci ; 41(13): 2828-2841, 2021 03 31.
Artigo em Inglês | MEDLINE | ID: mdl-33632727

RESUMO

Common fusion machinery mediates the Ca2+-dependent exocytosis of synaptic vesicles (SVs) and dense-core vesicles (DCVs). Previously, Synapsin Ia (Syn Ia) was found to localize to SVs, essential for mobilizing SVs to the plasma membrane through phosphorylation. However, whether (or how) the phosphoprotein Syn Ia plays a role in regulating DCV exocytosis remains unknown. To answer these questions, we measured the dynamics of DCV exocytosis by using single-vesicle amperometry in PC12 cells (derived from the pheochromocytoma of rats of unknown sex) overexpressing wild-type or phosphodeficient Syn Ia. We found that overexpression of phosphodeficient Syn Ia decreased the DCV secretion rate, specifically via residues previously shown to undergo calmodulin-dependent kinase (CaMK)-mediated phosphorylation (S9, S566, and S603). Moreover, the fusion pore kinetics during DCV exocytosis were found to be differentially regulated by Syn Ia and two phosphodeficient Syn Ia mutants (Syn Ia-S62A and Syn Ia-S9,566,603A). Kinetic analysis suggested that Syn Ia may regulate the closure and dilation of DCV fusion pores via these sites, implying the potential interactions of Syn Ia with certain DCV proteins involved in the regulation of fusion pore dynamics. Furthermore, we predicted the interaction of Syn Ia with several DCV proteins, including Synaptophysin (Syp) and soluble N-ethylmaleimide-sensitive factor attachment receptor (SNARE) proteins. By immunoprecipitation, we found that Syn Ia interacted with Syp via phosphorylation. Moreover, a proximity ligation assay (PLA) confirmed their phosphorylation-dependent, in situ interaction on DCVs. Together, these findings reveal a phosphorylation-mediated regulation of DCV exocytosis by Syn Ia.SIGNIFICANCE STATEMENT Although they exhibit distinct exocytosis dynamics upon stimulation, synaptic vesicles (SVs) and dense-core vesicles (DCVs) may undergo co-release in neurons and neuroendocrine cells through an undefined molecular mechanism. Synapsin Ia (Syn Ia) is known to recruit SVs to the plasma membrane via phosphorylation. Here, we examined whether Syn Ia also affects the dynamics of DCV exocytosis. We showed that Syn Ia regulates the DCV secretion rate and fusion pore kinetics during DCV exocytosis. Moreover, Syn Ia-mediated regulation of DCV exocytosis depends on phosphorylation. We further found that Syn Ia interacts with Synaptophysin (Syp) on DCVs in a phosphorylation-dependent manner. Thus, these results suggest that Syn Ia may regulate the release of DCVs via phosphorylation.


Assuntos
Membrana Celular/metabolismo , Exocitose/fisiologia , Vesículas Secretórias/metabolismo , Sinapsinas/metabolismo , Vesículas Sinápticas/metabolismo , Animais , Células PC12 , Fosfoproteínas/metabolismo , Ratos
8.
Int J Mol Sci ; 22(4)2021 Feb 09.
Artigo em Inglês | MEDLINE | ID: mdl-33572172

RESUMO

Low complexity regions (LCRs) are very frequent in protein sequences, generally having a lower propensity to form structured domains and tending to be much less evolutionarily conserved than globular domains. Their higher abundance in eukaryotes and in species with more cellular types agrees with a growing number of reports on their function in protein interactions regulated by post-translational modifications. LCRs facilitate the increase of regulatory and network complexity required with the emergence of organisms with more complex tissue distribution and development. Although the low conservation and structural flexibility of LCRs complicate their study, evolutionary studies of proteins across species have been used to evaluate their significance and function. To investigate how to apply this evolutionary approach to the study of LCR function in protein-protein interactions, we performed a detailed analysis for Huntingtin (HTT), a large protein that is a hub for interaction with hundreds of proteins, has a variety of LCRs, and for which partial structural information (in complex with HAP40) is available. We hypothesize that proteins RASA1, SYN2, and KAT2B may compete with HAP40 for their attachment to the core of HTT using similar LCRs. Our results illustrate how evolution might favor the interplay of LCRs with domains, and the possibility of detecting multiple modes of LCR-mediated protein-protein interactions with a large hub such as HTT when enough protein interaction data is available.


Assuntos
Evolução Molecular , Proteína Huntingtina/metabolismo , Proteínas Nucleares/metabolismo , Motivos de Aminoácidos/genética , Sequência de Aminoácidos/genética , Animais , Humanos , Proteína Huntingtina/química , Proteína Huntingtina/genética , Proteína Huntingtina/ultraestrutura , Microscopia Eletrônica , Proteínas Nucleares/química , Proteínas Nucleares/genética , Proteínas Nucleares/ultraestrutura , Ligação Proteica/genética , Conformação Proteica em alfa-Hélice/genética , Domínios Proteicos/genética , Mapeamento de Interação de Proteínas , Mapas de Interação de Proteínas , Alinhamento de Sequência , Sinapsinas/química , Sinapsinas/metabolismo , Proteína p120 Ativadora de GTPase/química , Proteína p120 Ativadora de GTPase/metabolismo , Fatores de Transcrição de p300-CBP/química , Fatores de Transcrição de p300-CBP/metabolismo
9.
J Neurosci ; 41(10): 2070-2075, 2021 03 10.
Artigo em Inglês | MEDLINE | ID: mdl-33558431

RESUMO

In this short review, I describe from personal experience how every step in the career of any scientist, no matter how disjointed and pragmatic each might seem at the time, will almost inevitably meld together, to help us all tackle novel projects. My postdoctoral research in Paul Greengard's laboratory, where I investigated neurotransmitter-mediated phosphorylation of Synapsin I, was instrumental in my career progression, and Paul's support was instrumental in my ability to make a leap into independent research.


Assuntos
Escolha da Profissão , Neurotransmissores , Sinapsinas , Humanos , Fosforilação
10.
Sci Rep ; 11(1): 1934, 2021 01 21.
Artigo em Inglês | MEDLINE | ID: mdl-33479314

RESUMO

Non-surgical gene delivery to the brain can be achieved following intravenous injection of viral vectors coupled with transcranial MRI-guided focused ultrasound (MRIgFUS) to temporarily and locally permeabilize the blood-brain barrier. Vector and promoter selection can provide neuronal expression in the brain, while limiting biodistribution and expression in peripheral organs. To date, the biodistribution of adeno-associated viruses (AAVs) within peripheral organs had not been quantified following intravenous injection and MRIgFUS delivery to the brain. We evaluated the quantity of viral DNA from the serotypes AAV9, AAV6, and a mosaic AAV1&2, expressing green fluorescent protein (GFP) under the neuron-specific synapsin promoter (syn). AAVs were administered intravenously during MRIgFUS targeting to the striatum and hippocampus in mice. The syn promoter led to undetectable levels of GFP expression in peripheral organs. In the liver, the biodistribution of AAV9 and AAV1&2 was 12.9- and 4.4-fold higher, respectively, compared to AAV6. The percentage of GFP-positive neurons in the FUS-targeted areas of the brain was comparable for AAV6-syn-GFP and AAV1&2-syn-GFP. In summary, MRIgFUS-mediated gene delivery with AAV6-syn-GFP had lower off-target biodistribution in the liver compared to AAV9 and AAV1&2, while providing neuronal GFP expression in the striatum and hippocampus.


Assuntos
Encéfalo/efeitos dos fármacos , Encéfalo/metabolismo , Dependovirus/genética , Fígado/efeitos dos fármacos , Animais , Barreira Hematoencefálica/efeitos dos fármacos , Encéfalo/diagnóstico por imagem , Terapia Genética , Vetores Genéticos/uso terapêutico , Proteínas de Fluorescência Verde/química , Proteínas de Fluorescência Verde/farmacologia , Humanos , Injeções Intravenosas , Fígado/diagnóstico por imagem , Imageamento por Ressonância Magnética , Camundongos , Neurônios/efeitos dos fármacos , Regiões Promotoras Genéticas , Sinapsinas/química , Sinapsinas/farmacologia , Distribuição Tecidual , Transdução Genética , Ultrassonografia
11.
Nat Commun ; 12(1): 263, 2021 01 11.
Artigo em Inglês | MEDLINE | ID: mdl-33431828

RESUMO

Clusters of tightly packed synaptic vesicles (SVs) are a defining feature of nerve terminals. While SVs are mobile within the clusters, the clusters have no boundaries consistent with a liquid phase. We previously found that purified synapsin, a peripheral SV protein, can assemble into liquid condensates and trap liposomes into them. How this finding relates to the physiological formation of SV clusters in living cells remains unclear. Here, we report that synapsin alone, when expressed in fibroblasts, has a diffuse cytosolic distribution. However, when expressed together with synaptophysin, an integral SV membrane protein previously shown to be localized on small synaptic-like microvesicles when expressed in non-neuronal cells, is sufficient to organize such vesicles in clusters highly reminiscent of SV clusters and with liquid-like properties. This minimal reconstitution system can be a powerful model to gain mechanistic insight into the assembly of structures which are of fundamental importance in synaptic transmission.


Assuntos
Neurônios/metabolismo , Sinapsinas/metabolismo , Vesículas Sinápticas/metabolismo , Sinaptofisina/metabolismo , Animais , Células COS , Proteína Quinase Tipo 2 Dependente de Cálcio-Calmodulina/metabolismo , Células Cultivadas , Chlorocebus aethiops , Citosol/metabolismo , Endocitose , Fibroblastos/metabolismo , Fibroblastos/ultraestrutura , Humanos , Camundongos , Eletricidade Estática , Vesículas Sinápticas/ultraestrutura
12.
Mol Cell ; 81(1): 13-24.e7, 2021 01 07.
Artigo em Inglês | MEDLINE | ID: mdl-33202250

RESUMO

Tethering of synaptic vesicles (SVs) to the active zone determines synaptic strength, although the molecular basis governing SV tethering is elusive. Here, we discover that small unilamellar vesicles (SUVs) and SVs from rat brains coat on the surface of condensed liquid droplets formed by active zone proteins RIM, RIM-BP, and ELKS via phase separation. Remarkably, SUV-coated RIM/RIM-BP condensates are encapsulated by synapsin/SUV condensates, forming two distinct SUV pools reminiscent of the reserve and tethered SV pools that exist in presynaptic boutons. The SUV-coated RIM/RIM-BP condensates can further cluster Ca2+ channels anchored on membranes. Thus, we reconstitute a presynaptic bouton-like structure mimicking the SV-tethered active zone with its one side attached to the presynaptic membrane and the other side connected to the synapsin-clustered SV condensates. The distinct interaction modes between membraneless protein condensates and membrane-based organelles revealed here have general implications in cellular processes, including vesicular formation and trafficking, organelle biogenesis, and autophagy.


Assuntos
Encéfalo/metabolismo , Canais de Cálcio/metabolismo , Terminações Pré-Sinápticas/metabolismo , Sinapsinas/metabolismo , Vesículas Sinápticas/metabolismo , Animais , Canais de Cálcio/genética , Humanos , Camundongos , Ratos , Sinapsinas/genética , Vesículas Sinápticas/genética
13.
Methods Mol Biol ; 2191: 109-134, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-32865742

RESUMO

Optogenetics provides a powerful approach for investigating neuronal electrophysiology at the scale required for drug discovery applications. Probing synaptic function with high throughput using optogenetics requires robust tools that enable both precise stimulation of and facile readout of synaptic activity. Here we describe two functional assays to achieve this end: (1) a pre-synaptic calcium assay that utilizes the channelrhodopsin, CheRiff, patterned optogenetic stimulus, and the pre-synaptically targeted calcium reporter jRGECO1a to monitor pre-synaptic changes in calcium influx and (2) a synaptic transmission assay in which CheRiff and cytosolic jRGECO1a are expressed in non-overlapping sets of neurons, enabling pre-synaptic stimulation and post-synaptic readout of activity. This chapter describes the methodology and practical considerations for implementation of these two assays.


Assuntos
Cálcio/metabolismo , Channelrhodopsins/genética , Neurônios/metabolismo , Optogenética/métodos , Animais , Canais de Cálcio Tipo N/genética , Humanos , Ratos , Transdução de Sinais/genética , Sinapses/genética , Sinapsinas/química , Transmissão Sináptica/genética
14.
Int J Mol Sci ; 21(24)2020 Dec 19.
Artigo em Inglês | MEDLINE | ID: mdl-33352696

RESUMO

COASY protein-associated neurodegeneration (CoPAN) is a rare but devastating genetic autosomal recessive disorder of inborn error of CoA metabolism, which shares with pantothenate kinase-associated neurodegeneration (PKAN) similar features, such as dystonia, parkinsonian traits, cognitive impairment, axonal neuropathy, and brain iron accumulation. These two disorders are part of the big group of neurodegenerations with brain iron accumulation (NBIA) for which no effective treatment is available at the moment. To date, the lack of a mammalian model, fully recapitulating the human disorder, has prevented the elucidation of pathogenesis and the development of therapeutic approaches. To gain new insights into the mechanisms linking CoA metabolism, iron dyshomeostasis, and neurodegeneration, we generated and characterized the first CoPAN disease mammalian model. Since CoA is a crucial metabolite, constitutive ablation of the Coasy gene is incompatible with life. On the contrary, a conditional neuronal-specific Coasy knock-out mouse model consistently developed a severe early onset neurological phenotype characterized by sensorimotor defects and dystonia-like movements, leading to premature death. For the first time, we highlighted defective brain iron homeostasis, elevation of iron, calcium, and magnesium, together with mitochondrial dysfunction. Surprisingly, total brain CoA levels were unchanged, and no signs of neurodegeneration were present.


Assuntos
Coenzima A Ligases/fisiologia , Hemocromatose/patologia , Ferro/metabolismo , Doenças Mitocondriais/patologia , Transtornos Motores/patologia , Neurodegeneração Associada a Pantotenato-Quinase/complicações , Sinapsinas/fisiologia , Animais , Coenzima A/metabolismo , Feminino , Hemocromatose/etiologia , Homeostase , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Mitocôndrias/genética , Mitocôndrias/metabolismo , Mitocôndrias/patologia , Doenças Mitocondriais/etiologia , Doenças Mitocondriais/metabolismo , Transtornos Motores/etiologia , Transtornos Motores/metabolismo
15.
Nutrients ; 12(11)2020 Nov 11.
Artigo em Inglês | MEDLINE | ID: mdl-33187266

RESUMO

In many previous studies, the preventive effects of peanut against aging and cognitive impairment have often been unclear, so to clarify the effects we first investigated effective markers for evaluating its effects in the hippocampus of senescence-accelerated mouse prone/8 (SAMP8) mice, mainly using proteomics. The effects of dietary high-oleic peanuts on the hair appearance of SAMP8, the expression of effective markers in the hippocampus, and the TBARS and amino acid contents of the hippocampus were examined. Hippocampus solute carrier family 1 (glial high-affinity glutamate transporter), calcium/calmodulin-dependent protein kinase type II, and sodium- and chloride-dependent GABA transporter, which all are considered to be closely related to glutamic acid concentration were decreased by feeding of the samples, and the GABA/glutamic acid ratio in the hippocampus was increased by feeding with the samples. The formation of glial fibrillary acidic protein and synapsin-2, which showed higher levels in the SAMP8 than in SAMR1, and the protein expression of tyrosine 3-monooxygenase/tryptophan 5-monooxygenase activation protein and dihydropteridine reductase, which are considered to be related to the formation of adrenergic neuron transmitters, were reduced by the feeding of peanuts and their germ-rich fraction. Ferulic acid, as an ester and minor component in peanuts, could be partly connected to the effect of peanuts. These results indicate that high-oleic peanuts and their germ-rich fraction can protect against aging and cognitive impairment by regulating protein expression, which could be measured by the proteomics of the above hippocampus proteins of SAMP8 and the hippocampal GABA/glutamic acid ratio.


Assuntos
Envelhecimento/metabolismo , Arachis/metabolismo , Disfunção Cognitiva/prevenção & controle , Hipocampo/metabolismo , Ácido Oleico/administração & dosagem , Animais , Biomarcadores/metabolismo , Disfunção Cognitiva/metabolismo , Dieta , Modelos Animais de Doenças , Ingestão de Energia , Proteína Glial Fibrilar Ácida/metabolismo , Camundongos , Ácido Oleico/metabolismo , Sinapsinas/metabolismo
16.
Chem Biol Interact ; 332: 109281, 2020 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-33022268

RESUMO

The development of fast-acting antidepressants is crucial considering that conventional antidepressants require a long period to elicit therapeutic effects. Creatine, an ergogenic guanidine-like compound, stands out as a candidate to exert fast antidepressant-like responses. The present study investigated whether a single dose of creatine elicits a fast response in mice submitted to the novelty-suppressed feeding (NSF) test, a paradigm that may assess depression-like and anxiety-like behaviors. Ketamine, an NMDA receptor antagonist that has rapid antidepressant effects, and conventional antidepressants were also tested. The involvement of the mTORC1 signaling pathway in the behavioral responses was also investigated. Biochemical analyses included hippocampal BDNF level (ELISA) and total and phospho-mTORC1 (Ser2448), PSD95 and synapsin immunocontent (Western Blotting). Creatine (10 mg/kg, p.o.) or ketamine (1 mg/kg, i.p.) reduced the latency to feed in the NSF test. Conversely, fluoxetine (10 mg/kg, p.o.), imipramine (1 mg/kg, p.o.) or bupropion (10 mg/kg, p.o.) did not alter this parameter. The administration of rapamycin (mTOR inhibitor, 0.2 nmol/site, i.c.v.) abolished the effects of creatine or ketamine in the NSF test. Creatine or ketamine-treated mice presented increased hippocampal BDNF level, an effect abolished by rapamycin. The hippocampal phospho-mTORC1 (Ser2448) immunocontent was increased by creatine, but not by ketamine. However, ketamine, but not creatine, increased PSD95 and synapsin immunocontent. Creatine and ketamine elicit a rapid response in the NSF test by a mechanism dependent on the mTORC1 signaling pathway.


Assuntos
Creatina/farmacologia , Comportamento Alimentar , Ketamina/farmacologia , Alvo Mecanístico do Complexo 1 de Rapamicina/metabolismo , Transdução de Sinais , Animais , Antidepressivos/farmacologia , Comportamento Animal/efeitos dos fármacos , Fator Neurotrófico Derivado do Encéfalo/metabolismo , Creatina/administração & dosagem , Proteína 4 Homóloga a Disks-Large/metabolismo , Feminino , Hipocampo/metabolismo , Ketamina/administração & dosagem , Camundongos , Fosforilação/efeitos dos fármacos , Sirolimo/farmacologia , Sinapsinas/metabolismo
17.
Cells ; 9(9)2020 09 13.
Artigo em Inglês | MEDLINE | ID: mdl-32933226

RESUMO

It is a well-known fact that following a proper routine light/dark or diurnal rhythm controls almost all biological processes. With the introduction of modern lighting and artificial illumination systems, continuous exposure to light at night may lead to the disruption of diurnal rhythm. However, the effect of light during the night on brain anatomy, physiology, and human body functions is less explored and poorly understood. In this study, we have evaluated the effect of exposure to dim light (5 lux) at night (dLAN) on Swiss Albino mice over a duration of three consecutive weeks. Results have revealed that exposure to dLAN led to an impairment of cognitive and non-cognitive behaviour, oxidative stress-mediated elevation of lipid peroxidation, and reduction of superoxide dismutase and catalase activity. It also led to the downregulation of hippocampal proteins (BDNF, Synapsin II and DCX) at both protein and mRNA level. Additionally, there was downregulation of CREB and SIRT1 mRNAs and neurodegeneration-associated miRNA21a-5p and miRNA34a-5p. The pyramidal and cortical neurons started showing pyknotic and chromatolysis characteristics. However, a dose of curcumin administered to the mice positively modulated these parameters in our experimental animals. We proposed the modulatory role of curcumin in addressing the deleterious effects of dLAN.


Assuntos
Ritmo Circadiano/efeitos dos fármacos , Ritmo Circadiano/efeitos da radiação , Curcumina/farmacologia , Luz/efeitos adversos , Fármacos Neuroprotetores/farmacologia , Animais , Comportamento Animal/efeitos dos fármacos , Comportamento Animal/efeitos da radiação , Fator Neurotrófico Derivado do Encéfalo/genética , Fator Neurotrófico Derivado do Encéfalo/metabolismo , Cognição/efeitos dos fármacos , Cognição/efeitos da radiação , Hipocampo/metabolismo , Masculino , Camundongos , Proteínas Associadas aos Microtúbulos/genética , Proteínas Associadas aos Microtúbulos/metabolismo , Neurogênese/efeitos dos fármacos , Neurogênese/efeitos da radiação , Neuropeptídeos/genética , Neuropeptídeos/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Estresse Oxidativo/efeitos da radiação , Reconhecimento Psicológico/efeitos dos fármacos , Reconhecimento Psicológico/efeitos da radiação , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/efeitos da radiação , Sinapsinas/genética , Sinapsinas/metabolismo
18.
Sci Rep ; 10(1): 15119, 2020 09 15.
Artigo em Inglês | MEDLINE | ID: mdl-32934297

RESUMO

Most of the gut functions are controlled by the enteric nervous system (ENS), a complex network of enteric neurons located throughout the wall of the gastrointestinal tract. The formation of ENS connectivity during the perinatal period critically underlies the establishment of gastrointestinal motility, but the factors involved in this maturation process remain poorly characterized. Here, we examined the role of Semaphorin 3A (Sema3A) on ENS maturation and its potential implication in Hirschsprung disease (HSCR), a developmental disorder of the ENS with impaired colonic motility. We found that Sema3A and its receptor Neuropilin 1 (NRP1) are expressed in the rat gut during the early postnatal period. At the cellular level, NRP1 is expressed by enteric neurons, where it is particularly enriched at growth areas of developing axons. Treatment of primary ENS cultures and gut explants with Sema3A restricts axon elongation and synapse formation. Comparison of the ganglionic colon of HSCR patients to the colon of patients with anorectal malformation shows reduced expression of the synaptic molecule synapsin 1 in HSCR, which is inversely correlated with Sema3A expression. Our study identifies Sema3A as a critical regulator of ENS connectivity and provides a link between altered ENS connectivity and HSCR.


Assuntos
Colo/patologia , Sistema Nervoso Entérico/patologia , Doença de Hirschsprung/patologia , Neurônios/patologia , Semaforina-3A/metabolismo , Sinapsinas/metabolismo , Animais , Colo/metabolismo , Sistema Nervoso Entérico/metabolismo , Feminino , Doença de Hirschsprung/metabolismo , Humanos , Lactente , Recém-Nascido , Masculino , Neurônios/metabolismo , Ratos , Semaforina-3A/genética , Sinapsinas/genética
19.
Int J Mol Sci ; 21(15)2020 Aug 04.
Artigo em Inglês | MEDLINE | ID: mdl-32759773

RESUMO

Senescence-accelerated mouse prone 10 (SAMP10) exhibits cerebral atrophy and depression-like behavior. A line of SAMP10 with spontaneous mutation in the Slc5a2 gene encoding the sodium-glucose cotransporter (SGLT) 2 was named SAMP10/TaSlc-Slc5a2slc (SAMP10-ΔSglt2) and was identified as a renal diabetes model. In contrast, a line of SAMP10 with no mutation in SGLT2 (SAMP10/TaIdrSlc, SAMP10(+)) was recently established under a specific pathogen-free condition. Here, we examined the mutation effect in SGLT2 on brain function and longevity. No differences were found in the survival curve, depression-like behavior, and age-related brain atrophy between SAMP10-ΔSglt2 and SAMP10(+). However, memory retention was lower in SAMP10-ΔSglt2 mice than SAMP10(+). Amyloid beta (A4) precursor-like protein 1 (Aplp1) expression was significantly lower in the hippocampus of SAMP10-ΔSGLT2 than in SAMP10(+) at 2 months of age, but was similar at 12 months of age. CaM kinase-like vesicle association (Camkv) expression was remarkably lower in SAMP10(+). These genes have been reported to be involved in dendrite function. Amyloid precursor proteins have been reported to involve in maintaining homeostasis of glucose and insulin. These results suggest that mutation in SGLT2 results in down-regulation of Aplp1 in young age, which can lead to poor memory retention in old age.


Assuntos
Envelhecimento/genética , Precursor de Proteína beta-Amiloide/genética , Transtornos da Memória/genética , Doenças Neurodegenerativas/genética , Transportador 2 de Glucose-Sódio/genética , Fatores Etários , Envelhecimento/patologia , Animais , Encéfalo/metabolismo , Encéfalo/patologia , Senescência Celular/genética , Regulação da Expressão Gênica/genética , Glucose/metabolismo , Humanos , Memória/fisiologia , Transtornos da Memória/patologia , Camundongos , Mutação/genética , Doenças Neurodegenerativas/metabolismo , Doenças Neurodegenerativas/patologia , Sinapsinas/metabolismo
20.
Mol Neurobiol ; 57(7): 3158-3170, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32495180

RESUMO

Depression is a common non-motor symptom in patients with Parkinson's disease (PD) and difficult to treat. Crocin is a natural multipotential neuroprotective compound that has been shown to elicit antidepressant activity and is promising for the therapy of neuropsychological diseases. Here, we investigated the therapeutic effect of crocin in a mouse model of Parkinson's disease depression (PDD) and clarified the underlying mechanism. We prepared 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced subacute mouse model of PD, and found that around 60% of the model mice showed depression-like behavior, using the forced swimming test (FST). A regime of 10-day treatment of crocin alleviated the PDD symptoms. The crocin reduced the structural damage in soma volume and axon length of neurons and inhibited their spontaneous discharge in dopaminergic (DA) neurons in the ventral tegmental area (VTA). Notably, the MPTP-treated mice showed the decrease in the critical signaling for synaptic plasticity, including the proteins of PSD-95, synapsin-1, and GluR-1, in the medial prefrontal cortex (mPFC) where it receives efferent from VTA and regulates depression-like behavior. However, crocin treatment rescued the defect of the mammalian target of rapamycin (mTOR) signaling in PDD mice. Furthermore, the antidepressant action of crocin was blunted after blockade of mTOR signaling with the antagonist rapamycin. In conclusion, our study demonstrated that crocin protected the DA projection neurons in the VTA through activating mTOR, which subsequently improved the neural synaptic plasticity of mPFC, and ameliorated depression-like behavior in PD mice.


Assuntos
Comportamento Animal/efeitos dos fármacos , Carotenoides/farmacologia , Depressão/metabolismo , Transtornos Parkinsonianos/metabolismo , Córtex Pré-Frontal/efeitos dos fármacos , Área Tegmentar Ventral/efeitos dos fármacos , Animais , Masculino , Camundongos , Vias Neurais/efeitos dos fármacos , Plasticidade Neuronal/efeitos dos fármacos , Córtex Pré-Frontal/metabolismo , Receptores de AMPA/metabolismo , Transdução de Sinais/efeitos dos fármacos , Sinapsinas/metabolismo , Área Tegmentar Ventral/metabolismo
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