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1.
JCI Insight ; 8(11)2023 06 08.
Artigo em Inglês | MEDLINE | ID: mdl-37159261

RESUMO

Cephalic tetanus (CT) is a severe form of tetanus that follows head wounds and the intoxication of cranial nerves by tetanus neurotoxin (TeNT). Hallmarks of CT are cerebral palsy, which anticipates the spastic paralysis of tetanus, and rapid evolution of cardiorespiratory deficit even without generalized tetanus. How TeNT causes this unexpected flaccid paralysis, and how the canonical spasticity then rapidly evolves into cardiorespiratory defects, remain unresolved aspects of CT pathophysiology. Using electrophysiology and immunohistochemistry, we demonstrate that TeNT cleaves its substrate vesicle-associated membrane protein within facial neuromuscular junctions and causes a botulism-like paralysis overshadowing tetanus spasticity. Meanwhile, TeNT spreads among brainstem neuronal nuclei and, as shown by an assay measuring the ventilation ability of CT mice, harms essential functions like respiration. A partial axotomy of the facial nerve revealed a potentially new ability of TeNT to undergo intra-brainstem diffusion, which allows the toxin to spread to brainstem nuclei devoid of direct peripheral efferents. This mechanism is likely to be involved in the transition from local to generalized tetanus. Overall, the present findings suggest that patients with idiopathic facial nerve palsy should be immediately considered for CT and treated with antisera to block the potential progression to a life-threatening form of tetanus.


Assuntos
Toxinas Botulínicas , Tétano , Camundongos , Animais , Toxinas Botulínicas/metabolismo , Junção Neuromuscular/metabolismo , Paralisia
2.
J Neurosci ; 43(23): 4234-4250, 2023 06 07.
Artigo em Inglês | MEDLINE | ID: mdl-37197980

RESUMO

Planning and execution of voluntary movement depend on the contribution of distinct classes of neurons in primary motor and premotor areas. However, timing and pattern of activation of GABAergic cells during specific motor behaviors remain only partly understood. Here, we directly compared the response properties of putative pyramidal neurons (PNs) and GABAergic fast-spiking neurons (FSNs) during spontaneous licking and forelimb movements in male mice. Recordings centered on the face/mouth motor field of the anterolateral motor cortex (ALM) revealed that FSNs fire longer than PNs and earlier for licking, but not for forelimb movements. Computational analysis revealed that FSNs carry vastly more information than PNs about the onset of movement. While PNs differently modulate their discharge during distinct motor acts, most FSNs respond with a stereotyped increase in firing rate. Accordingly, the informational redundancy was greater among FSNs than PNs. Finally, optogenetic silencing of a subset of FSNs reduced spontaneous licking movement. These data suggest that a global rise of inhibition contributes to the initiation and execution of spontaneous motor actions.SIGNIFICANCE STATEMENT Our study contributes to clarifying the causal role of fast-spiking neurons (FSNs) in driving initiation and execution of specific, spontaneous movements. Within the face/mouth motor field of mice premotor cortex, FSNs fire before pyramidal neurons (PNs) with a specific activation pattern: they reach their peak of activity earlier than PNs during the initiation of licking, but not of forelimb, movements; duration of FSNs activity is also greater and exhibits less selectivity for the movement type, as compared with that of PNs. Accordingly, FSNs appear to carry more redundant information than PNs. Optogenetic silencing of FSNs reduced spontaneous licking movement, suggesting that FSNs contribute to the initiation and execution of specific spontaneous movements, possibly by sculpting response selectivity of nearby PNs.


Assuntos
Córtex Motor , Masculino , Camundongos , Animais , Córtex Motor/fisiologia , Interneurônios/fisiologia , Células Piramidais/fisiologia , Movimento/fisiologia , Neurônios GABAérgicos
3.
Neuro Oncol ; 25(8): 1463-1473, 2023 08 03.
Artigo em Inglês | MEDLINE | ID: mdl-36805257

RESUMO

BACKGROUND: Glioblastoma growth impacts on the structure and physiology of peritumoral neuronal networks, altering the activity of pyramidal neurons which drives further tumor progression. It is therefore of paramount importance to identify glioma-induced changes in pyramidal neurons, since they represent a key therapeutic target. METHODS: We longitudinal monitored visual evoked potentials after the orthotopic implant of murine glioma cells into the mouse occipital cortex. With laser microdissection, we analyzed layer II-III pyramidal neurons molecular profile and with local field potentials recordings we evaluated the propensity to seizures in glioma-bearing animals with respect to control mice. RESULTS: We determine the time course of neuronal dysfunction of glioma-bearing mice and we identify a symptomatic stage, based on the decay of visual response. At that time point, we microdissect layer II-III pyramidal neurons and evaluate the expression of a panel of genes involved in synaptic transmission and neuronal excitability. Compared to the control group, peritumoral neurons show a decrease in the expression of the SNARE complex gene SNAP25 and the alpha1 subunit of the GABA-A receptor. No significant changes are detected in glutamatergic (ie, AMPA or NMDA receptor subunit) markers. Further reduction of GABA-A signaling by delivery of a benzodiazepine inverse agonist, DMCM (methyl-6,7-dimethoxy-4-ethyl-beta-carboline-3-carboxylate) precipitates seizures in 2 mouse models of tumor-bearing mice. CONCLUSIONS: These studies reveal novel molecular changes that occur in the principal cells of the tumor-adjacent zone. These modifications may be therapeutically targeted to ameliorate patients' quality of life.


Assuntos
Potenciais Evocados Visuais , Glioma , Camundongos , Animais , Agonismo Inverso de Drogas , Qualidade de Vida , Convulsões , Neurônios , Glioma/metabolismo
4.
Cereb Cortex ; 33(7): 4173-4187, 2023 03 21.
Artigo em Inglês | MEDLINE | ID: mdl-36089833

RESUMO

The epileptic brain is the result of a sequence of events transforming normal neuronal populations into hyperexcitable networks supporting recurrent seizure generation. These modifications are known to induce fundamental alterations of circuit function and, ultimately, of behavior. However, how hyperexcitability affects information processing in cortical sensory circuits is not yet fully understood. Here, we investigated interlaminar alterations in sensory processing of the visual cortex in a mouse model of focal epilepsy. We found three main circuit dynamics alterations in epileptic mice: (i) a spreading of visual contrast-driven gamma modulation across layers, (ii) an increase in firing rate that is layer-unspecific for excitatory units and localized in infragranular layers for inhibitory neurons, and (iii) a strong and contrast-dependent locking of firing units to network activity. Altogether, our data show that epileptic circuits display a functional disruption of layer-specific organization of visual sensory processing, which could account for visual dysfunction observed in epileptic subjects. Understanding these mechanisms paves the way to circuital therapeutic interventions for epilepsy.


Assuntos
Epilepsias Parciais , Epilepsia , Neocórtex , Camundongos , Animais , Neurônios/fisiologia , Percepção Visual
5.
Neurobiol Dis ; 174: 105894, 2022 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-36240950

RESUMO

Experience-dependent neuronal changes and brain plasticity occur throughout life as animals adapt to their environment. Structural, morphological, and cellular modifications promoted by exposure to environmental enrichment (EE) have been reported to improve neuronal functions, increase hippocampal neurogenesis, ameliorate memory tasks and cognitive performance, and have beneficial effects on several brain diseases, including cancer. We specifically addressed the role of the EE in counteracting neuronal dysfunction in mice bearing glioma in the primary visual cortex. By recording spontaneous and evoked currents with patch clamp techniques in acute slices obtained from standard and enriched-housed mice, we found that the presence of glioma globally reduced the excitatory and inhibitory transmissions in the peritumoral area. The exposure to an enriched environment counteracts the tumor-mediated depression of both excitatory and inhibitory neuronal activities, with a more pronounced impact on evoked transmission. The effect of EE on glioma was also associated with reduced tumor cell proliferation. These results elucidate the impact of EE on excitatory and inhibitory neurotransmission of the primary visual cortex in control and glioma-bearing mice.


Assuntos
Glioma , Córtex Visual Primário , Camundongos , Animais , Meio Ambiente , Plasticidade Neuronal/fisiologia , Transmissão Sináptica/fisiologia
6.
J Headache Pain ; 23(1): 125, 2022 Sep 29.
Artigo em Inglês | MEDLINE | ID: mdl-36175826

RESUMO

BACKGROUND: Migraine affects a significant fraction of the world population, yet its etiology is not completely understood. In vitro results highlighted thalamocortical and intra-cortical glutamatergic synaptic gain-of-function associated with a monogenic form of migraine (familial-hemiplegic-migraine-type-1: FHM1). However, how these alterations reverberate on cortical activity remains unclear. As altered responsivity to visual stimuli and abnormal processing of visual sensory information are common hallmarks of migraine, herein we investigated the effects of FHM1-driven synaptic alterations in the visual cortex of awake mice. METHODS: We recorded extracellular field potentials from the primary visual cortex (V1) of head-fixed awake FHM1 knock-in (n = 12) and wild type (n = 12) mice in response to square-wave gratings with different visual contrasts. Additionally, we reproduced in silico the obtained experimental results with a novel spiking neurons network model of mouse V1, by implementing in the model both the synaptic alterations characterizing the FHM1 genetic mouse model adopted. RESULTS: FHM1 mice displayed similar amplitude but slower temporal evolution of visual evoked potentials. Visual contrast stimuli induced a lower increase of multi-unit activity in FHM1 mice, while the amount of information content about contrast level remained, however, similar to WT. Spectral analysis of the local field potentials revealed an increase in the ß/low γ range of WT mice following the abrupt reversal of contrast gratings. Such frequency range transitioned to the high γ range in FHM1 mice. Despite this change in the encoding channel, these oscillations preserved the amount of information conveyed about visual contrast. The computational model showed how these network effects may arise from a combination of changes in thalamocortical and intra-cortical synaptic transmission, with the former inducing a lower cortical activity and the latter inducing the higher frequencies É£ oscillations. CONCLUSIONS: Contrast-driven É£ modulation in V1 activity occurs at a much higher frequency in FHM1. This is likely to play a role in the altered processing of visual information. Computational studies suggest that this shift is specifically due to enhanced cortical excitatory transmission. Our network model can help to shed light on the relationship between cellular and network levels of migraine neural alterations.


Assuntos
Transtornos de Enxaqueca , Enxaqueca com Aura , Córtex Visual , Animais , Modelos Animais de Doenças , Potenciais Evocados Visuais , Camundongos , Transtornos de Enxaqueca/genética
7.
Development ; 149(20)2022 10 15.
Artigo em Inglês | MEDLINE | ID: mdl-35993299

RESUMO

Using the timely re-activation of WNT signalling in neuralizing human induced pluripotent stem cells (hiPSCs), we have produced neural progenitor cells with a gene expression profile typical of human embryonic dentate gyrus (DG) cells. Notably, in addition to continuous WNT signalling, a specific laminin isoform is crucial to prolonging the neural stem state and to extending progenitor cell proliferation for over 200 days in vitro. Laminin 511 is indeed specifically required to support proliferation and to inhibit differentiation of hippocampal progenitor cells for extended time periods when compared with a number of different laminin isoforms assayed. Global gene expression profiles of these cells suggest that a niche of laminin 511 and WNT signalling is sufficient to maintain their capability to undergo typical hippocampal neurogenesis. Moreover, laminin 511 signalling sustains the expression of a set of genes responsible for the maintenance of a hippocampal neurogenic niche. Finally, xenograft of human DG progenitors into the DG of adult immunosuppressed host mice produces efficient integration of neurons that innervate CA3 layer cells spanning the same area of endogenous hippocampal neuron synapses.


Assuntos
Células-Tronco Pluripotentes Induzidas , Laminina , Animais , Diferenciação Celular/genética , Giro Denteado , Hipocampo/metabolismo , Humanos , Células-Tronco Pluripotentes Induzidas/metabolismo , Laminina/metabolismo , Camundongos , Neurogênese/genética , Via de Sinalização Wnt
8.
JIMD Rep ; 63(1): 50-65, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-35028271

RESUMO

Krabbe disease (KD; or globoid cell leukodystrophy) is an autosomal recessive lysosomal storage disorder caused by deficiency of the galactosylceramidase (GALC) enzyme. No cure is currently available for KD. Clinical applied treatments are supportive only. Recently, we demonstrated that two differently acting autophagy inducers (lithium and rapamycin) can improve some KD hallmarks in-vitro, laying the foundation for their in-vivo pre-clinical testing. Here, we test lithium carbonate in-vivo, in the spontaneous mouse model for KD, the Twitcher (TWI) mouse. The drug is administered ad libitum via drinking water (600 mg/L) starting from post natal day 20. We longitudinally monitor the mouse motor performance through the grip strength, the hanging wire and the rotarod tests, and a set of biochemical parameters related to the KD pathogenesis [i.e., GALC enzymatic activity, psychosine (PSY) accumulation and astrogliosis]. Additionally, we investigate the expression of some crucial markers related to the two pathways that could be altered by lithium: the autophagy and the ß-catenin-dependent pathways. Results demonstrate that lithium has not a significant rescue effect on the TWI phenotype, although it can slightly and transiently improves muscle strength. We also show that lithium, with this administration protocol, is unable to stimulate autophagy in the TWI mice central nervous system, whereas results suggest that it can restore the ß-catenin activation status in the TWI sciatic nerve. Overall, these data provide intriguing inputs for further evaluations of lithium treatment in TWI mice.

9.
Prog Neurobiol ; 208: 102186, 2022 01.
Artigo em Inglês | MEDLINE | ID: mdl-34780864

RESUMO

The brain operates through the synaptic interaction of distant neurons within flexible, often heterogeneous, distributed systems. Histological studies have detailed the connections between distant neurons, but their functional characterization deserves further exploration. Studies performed on the corpus callosum in animals and humans are unique in that they capitalize on results obtained from several neuroscience disciplines. Such data inspire a new interpretation of the function of callosal connections and delineate a novel road map, thus paving the way toward a general theory of cortico-cortical connectivity. Here we suggest that callosal axons can drive their post-synaptic targets preferentially when coupled to other inputs endowing the cortical network with a high degree of conditionality. This might depend on several factors, such as their pattern of convergence-divergence, the excitatory and inhibitory operation mode, the range of conduction velocities, the variety of homotopic and heterotopic projections and, finally, the state-dependency of their firing. We propose that, in addition to direct stimulation of post-synaptic targets, callosal axons often play a conditional driving or modulatory role, which depends on task contingencies, as documented by several recent studies.


Assuntos
Axônios , Corpo Caloso , Animais , Axônios/fisiologia , Encéfalo , Corpo Caloso/fisiologia , Humanos , Vias Neurais/fisiologia , Neurônios
10.
Cells ; 10(11)2021 11 06.
Artigo em Inglês | MEDLINE | ID: mdl-34831273

RESUMO

Ischemic damage in brain tissue triggers a cascade of molecular and structural plastic changes, thus influencing a wide range of cell-to-cell interactions. Understanding and manipulating this scenario of intercellular connections is the Holy Grail for post-stroke neurorehabilitation. Here, we discuss the main findings in the literature related to post-stroke alterations in cell-to-cell interactions, which may be either detrimental or supportive for functional recovery. We consider both neural and non-neural cells, starting from astrocytes and reactive astrogliosis and moving to the roles of the oligodendrocytes in the support of vulnerable neurons and sprouting inhibition. We discuss the controversial role of microglia in neural inflammation after injury and we conclude with the description of post-stroke alterations in pyramidal and GABAergic cells interactions. For all of these sections, we review not only the spontaneous evolution in cellular interactions after ischemic injury, but also the experimental strategies which have targeted these interactions and that are inspiring novel therapeutic strategies for clinical application.


Assuntos
Comunicação Celular , Recuperação de Função Fisiológica , Acidente Vascular Cerebral/patologia , Acidente Vascular Cerebral/fisiopatologia , Animais , Isquemia Encefálica/patologia , Isquemia Encefálica/fisiopatologia , Humanos , Plasticidade Neuronal , Oligodendroglia/patologia
11.
eNeuro ; 8(6)2021.
Artigo em Inglês | MEDLINE | ID: mdl-34663617

RESUMO

γ Band plays a key role in the encoding of visual features in the primary visual cortex (V1). In rodents V1 two ranges within the γ band are sensitive to contrast: a broad γ band (BB) increasing with contrast, and a narrow γ band (NB), peaking at ∼60 Hz, decreasing with contrast. The functional roles of the two bands and the neural circuits originating them are not completely clear yet. Here, we show, combining experimental and simulated data, that in mice V1 (1) BB carries information about high contrast and NB about low contrast; (2) BB modulation depends on excitatory-inhibitory interplay in the cortex, while NB modulation is because of entrainment to the thalamic drive. In awake mice presented with alternating gratings, NB power progressively decreased from low to intermediate levels of contrast where it reached a plateau. Conversely, BB power was constant across low levels of contrast, but it progressively increased from intermediate to high levels of contrast. Furthermore, BB response was stronger immediately after contrast reversal, while the opposite held for NB. These complementary modulations were reproduced by a recurrent excitatory-inhibitory leaky integrate-and-fire network provided that the thalamic inputs were composed of a sustained and a periodic component having complementary sensitivity ranges. These results show that in rodents the thalamic-driven NB plays a specific key role in encoding visual contrast. Moreover, we propose a simple and effective network model of response to visual stimuli in rodents that might help in investigating network dysfunctions of pathologic visual information processing.


Assuntos
Córtex Visual , Animais , Camundongos , Neurônios , Estimulação Luminosa , Córtex Visual Primário , Percepção Visual
12.
Molecules ; 26(19)2021 Oct 02.
Artigo em Inglês | MEDLINE | ID: mdl-34641541

RESUMO

Glioblastoma Multiforme (GBM) is a brain tumor with a poor prognosis and low survival rates. GBM is diagnosed at an advanced stage, so little information is available on the early stage of the disease and few improvements have been made for earlier diagnosis. Longitudinal murine models are a promising platform for biomarker discovery as they allow access to the early stages of the disease. Nevertheless, their use in proteomics has been limited owing to the low sample amount that can be collected at each longitudinal time point. Here we used optimized microproteomics workflows to investigate longitudinal changes in the protein profile of serum, serum small extracellular vesicles (sEVs), and cerebrospinal fluid (CSF) in a GBM murine model. Baseline, pre-symptomatic, and symptomatic tumor stages were determined using non-invasive motor tests. Forty-four proteins displayed significant differences in signal intensities during GBM progression. Dysregulated proteins are involved in cell motility, cell growth, and angiogenesis. Most of the dysregulated proteins already exhibited a difference from baseline at the pre-symptomatic stage of the disease, suggesting that early effects of GBM might be detectable before symptom onset.


Assuntos
Neoplasias Encefálicas/sangue , Neoplasias Encefálicas/líquido cefalorraquidiano , Glioblastoma/sangue , Glioblastoma/líquido cefalorraquidiano , Proteômica/métodos , Animais , Biomarcadores Tumorais/sangue , Biomarcadores Tumorais/líquido cefalorraquidiano , Proteínas Sanguíneas/análise , Proteínas do Líquido Cefalorraquidiano/análise , Vesículas Extracelulares/patologia , Feminino , Masculino , Camundongos Endogâmicos C57BL , Neoplasias Experimentais/sangue , Neoplasias Experimentais/líquido cefalorraquidiano , Neoplasias Experimentais/patologia , Fluxo de Trabalho
13.
Brain Commun ; 3(3): fcab162, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34466801

RESUMO

Pathogenic NR2F1 variants cause a rare autosomal dominant neurodevelopmental disorder referred to as the Bosch-Boonstra-Schaaf Optic Atrophy Syndrome. Although visual loss is a prominent feature seen in affected individuals, the molecular and cellular mechanisms contributing to visual impairment are still poorly characterized. We conducted a deep phenotyping study on a cohort of 22 individuals carrying pathogenic NR2F1 variants to document the neurodevelopmental and ophthalmological manifestations, in particular the structural and functional changes within the retina and the optic nerve, which have not been detailed previously. The visual impairment became apparent in early childhood with small and/or tilted hypoplastic optic nerves observed in 10 cases. High-resolution optical coherence tomography imaging confirmed significant loss of retinal ganglion cells with thinning of the ganglion cell layer, consistent with electrophysiological evidence of retinal ganglion cells dysfunction. Interestingly, for those individuals with available longitudinal ophthalmological data, there was no significant deterioration in visual function during the period of follow-up. Diffusion tensor imaging tractography studies showed defective connections and disorganization of the extracortical visual pathways. To further investigate how pathogenic NR2F1 variants impact on retinal and optic nerve development, we took advantage of an Nr2f1 mutant mouse disease model. Abnormal retinogenesis in early stages of development was observed in Nr2f1 mutant mice with decreased retinal ganglion cell density and disruption of retinal ganglion cell axonal guidance from the neural retina into the optic stalk, accounting for the development of optic nerve hypoplasia. The mutant mice showed significantly reduced visual acuity based on electrophysiological parameters with marked conduction delay and decreased amplitude of the recordings in the superficial layers of the visual cortex. The clinical observations in our study cohort, supported by the mouse data, suggest an early neurodevelopmental origin for the retinal and optic nerve head defects caused by NR2F1 pathogenic variants, resulting in congenital vision loss that seems to be non-progressive. We propose NR2F1 as a major gene that orchestrates early retinal and optic nerve head development, playing a key role in the maturation of the visual system.

14.
J Neurosci Res ; 99(9): 2216-2227, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34051113

RESUMO

Oligodendrocyte progenitor cells (OPCs) are responsible for generating oligodendrocytes, the myelinating cells of the CNS. Life-long myelination is promoted by neuronal activity and is essential for neural network plasticity and learning. OPCs are known to contact synapses and it is proposed that neuronal synaptic activity in turn regulates their behavior. To examine this in the adult, we performed unilateral injection of the synaptic blocker botulinum neurotoxin A (BoNT/A) into the hippocampus of adult mice. We confirm BoNT/A cleaves SNAP-25 in the CA1 are of the hippocampus, which has been proven to block neurotransmission. Notably, BoNT/A significantly decreased OPC density and caused their shrinkage, as determined by immunolabeling for the OPC marker NG2. Furthermore, BoNT/A resulted in an overall decrease in the number of OPC processes, as well as a decrease in their lengths and branching frequency. These data indicate that synaptic activity is important for maintaining adult OPC numbers and cellular integrity, which is relevant to pathophysiological scenarios characterized by dysregulation of synaptic activity, such as age-related cognitive decline, Multiple Sclerosis and Alzheimer's disease.


Assuntos
Toxinas Botulínicas Tipo A/administração & dosagem , Hipocampo/efeitos dos fármacos , Plasticidade Neuronal/efeitos dos fármacos , Células Precursoras de Oligodendrócitos/efeitos dos fármacos , Sinapses/efeitos dos fármacos , Animais , Contagem de Células/métodos , Hipocampo/citologia , Hipocampo/patologia , Injeções Intraventriculares , Camundongos , Camundongos Endogâmicos C57BL , Plasticidade Neuronal/fisiologia , Células Precursoras de Oligodendrócitos/patologia , Oligodendroglia/efeitos dos fármacos , Oligodendroglia/patologia , Sinapses/patologia , Sinapses/fisiologia
15.
Toxins (Basel) ; 13(3)2021 03 08.
Artigo em Inglês | MEDLINE | ID: mdl-33800135

RESUMO

Current strategies for glioma treatment are only partly effective because of the poor selectivity for tumoral cells. Hence, the necessity to identify novel approaches is urgent. Recent studies highlighted the effectiveness of the bacterial protein cytotoxic necrotizing factor 1 (CNF1) in reducing tumoral mass, increasing survival of glioma-bearing mice and protecting peritumoral neural tissue from dysfunction. However, native CNF1 needs to be delivered into the brain, because of its incapacity to cross the blood-brain barrier (BBB) per se, thus hampering its clinical translation. To allow a non-invasive administration of CNF1, we here developed a chimeric protein (CTX-CNF1) conjugating CNF1 with chlorotoxin (CTX), a peptide already employed in clinics due to its ability of passing the BBB and selectively binding glioma cells. After systemic administration, we found that CTX-CNF1 is able to target glioma cells and significantly prolong survival of glioma-bearing mice. Our data point out the potentiality of CTX-CNF1 as a novel effective tool to treat gliomas.


Assuntos
Antineoplásicos/farmacologia , Toxinas Bacterianas/farmacologia , Neoplasias Encefálicas/tratamento farmacológico , Proteínas de Escherichia coli/farmacologia , Glioma/tratamento farmacológico , Venenos de Escorpião/farmacologia , Animais , Antineoplásicos/metabolismo , Toxinas Bacterianas/metabolismo , Barreira Hematoencefálica/metabolismo , Neoplasias Encefálicas/metabolismo , Neoplasias Encefálicas/patologia , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Senescência Celular/efeitos dos fármacos , Proteínas de Escherichia coli/metabolismo , Glioma/metabolismo , Glioma/patologia , Humanos , Injeções Intravenosas , Camundongos Endogâmicos C57BL , Proteínas Recombinantes de Fusão/farmacologia , Venenos de Escorpião/metabolismo
16.
Biomolecules ; 11(1)2020 12 23.
Artigo em Inglês | MEDLINE | ID: mdl-33374753

RESUMO

Krabbe disease (KD, or globoid cell leukodystrophy; OMIM #245200) is an inherited neurodegenerative condition belonging to the class of the lysosomal storage disorders. It is caused by genetic alterations in the gene encoding for the enzyme galactosylceramidase, which is responsible for cleaving the glycosydic linkage of galatosylsphingosine (psychosine or PSY), a highly cytotoxic molecule. Here, we describe morphological and functional alterations in the visual system of the Twitcher (TWI) mouse, the most used animal model of Krabbe disease. We report in vivo electrophysiological recordings showing defective basic functional properties of the TWI primary visual cortex. In particular, we demonstrate a reduced visual acuity and contrast sensitivity, and a delayed visual response. Specific neuropathological alterations are present in the TWI visual cortex, with reduced myelination, increased astrogliosis and microglia activation, and around the whole brain. Finally, we quantify PSY content in the brain and optic nerves by high-pressure liquid chromatography-mass spectrometry methods. An increasing PSY accumulation with time, the characteristic hallmark of KD, is found in both districts. These results represent the first complete characterization of the TWI visual system. Our data set a baseline for an easy testing of potential therapies for this district, which is also dramatically affected in KD patients.


Assuntos
Galactosilceramidase/genética , Leucodistrofia de Células Globoides/genética , Doenças por Armazenamento dos Lisossomos/genética , Córtex Visual/metabolismo , Animais , Encéfalo/metabolismo , Encéfalo/patologia , Modelos Animais de Doenças , Fenômenos Eletrofisiológicos , Galactosilceramidase/metabolismo , Humanos , Leucodistrofia de Células Globoides/metabolismo , Leucodistrofia de Células Globoides/patologia , Doenças por Armazenamento dos Lisossomos/metabolismo , Doenças por Armazenamento dos Lisossomos/patologia , Camundongos , Bainha de Mielina/metabolismo , Psicosina/genética , Psicosina/metabolismo , Córtex Visual/patologia
17.
Front Cell Neurosci ; 14: 606142, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33362472

RESUMO

Neuronal hyperexcitability often results from an unbalance between excitatory and inhibitory neurotransmission, but the synaptic alterations leading to enhanced seizure propensity are only partly understood. Taking advantage of a mouse model of neocortical epilepsy, we used a combination of photoconversion and electron microscopy to assess changes in synaptic vesicles pools in vivo. Our analyses reveal that epileptic networks show an early onset lengthening of active zones at inhibitory synapses, together with a delayed spatial reorganization of recycled vesicles at excitatory synapses. Proteomics of synaptic content indicate that specific proteins were increased in epileptic mice. Altogether, our data reveal a complex landscape of nanoscale changes affecting the epileptic synaptic release machinery. In particular, our findings show that an altered positioning of release-competent vesicles represent a novel signature of epileptic networks.

18.
Sci Rep ; 10(1): 20498, 2020 11 24.
Artigo em Inglês | MEDLINE | ID: mdl-33235327

RESUMO

Longitudinal analysis of disease models enables the molecular changes due to disease progression or therapeutic intervention to be better resolved. Approximately 75 µl of serum can be drawn from a mouse every 14 days. To date no methods have been reported that are able to analyze the proteome of small extracellular vesicles (sEV's) from such low serum volumes. Here we report a method for the proteomics analysis of sEV's from 50 µl of serum. Two sEV isolation procedures were first compared; precipitation based purification (PPT) and size exclusion chromatography (SEC). The methodological comparison confirmed that SEC led to purer sEV's both in terms of size and identified proteins. The procedure was then scaled down and the proteolytic digestion further optimized. The method was then applied to a longitudinal study of serum-sEV proteome changes in a glioblastoma multiforme (GBM) mouse model. Serum was collected at multiple time points, sEV's isolated and their proteins analyzed. The protocol enabled 274 protein groups to be identified and quantified. The longitudinal analysis revealed 25 deregulated proteins in GBM serum sEV's including proteins previously shown to be associated with GBM progression and metastasis (Myh9, Tln-1, Angpt1, Thbs1).


Assuntos
Neoplasias Encefálicas/sangue , Vesículas Extracelulares/metabolismo , Glioblastoma/sangue , Proteômica , Animais , Neoplasias Encefálicas/patologia , Cromatografia em Gel , Modelos Animais de Doenças , Vesículas Extracelulares/ultraestrutura , Glioblastoma/patologia , Estudos Longitudinais , Camundongos Endogâmicos C57BL , Proteólise
19.
Artigo em Inglês | MEDLINE | ID: mdl-32764487

RESUMO

Currently, high-grade gliomas are the most difficult brain cancers to treat and all the approved experimental treatments do not offer long-term benefits regarding symptom improvement. Epidemiological studies indicate that exercise decreases the risk of brain cancer mortality, but a direct relationship between physical exercise and glioma progression has not been established so far. Here, we exploited a mouse model of high-grade glioma to directly test the impact of voluntary physical exercise on the tumor proliferation and motor capabilities of affected animals. We report that exposing symptomatic, glioma-bearing mice to running wheels (i) reduced the proliferation rate of tumors implanted in the motor cortex and (ii) delayed glioma-induced motor dysfunction. Thus, voluntary physical exercise might represent a supportive intervention that complements existing neuro-oncologic therapies, contributing to the preservation of functional motor ability and counteracting the detrimental effects of glioma on behavioral output.


Assuntos
Neoplasias Encefálicas , Proliferação de Células , Glioma , Condicionamento Físico Animal , Animais , Neoplasias Encefálicas/terapia , Modelos Animais de Doenças , Terapia por Exercício , Glioma/terapia , Camundongos , Camundongos Endogâmicos C57BL
20.
Front Syst Neurosci ; 14: 31, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32733210

RESUMO

Being able to replicate real experiments with computational simulations is a unique opportunity to refine and validate models with experimental data and redesign the experiments based on simulations. However, since it is technically demanding to model all components of an experiment, traditional approaches to modeling reduce the experimental setups as much as possible. In this study, our goal is to replicate all the relevant features of an experiment on motor control and motor rehabilitation after stroke. To this aim, we propose an approach that allows continuous integration of new experimental data into a computational modeling framework. First, results show that we could reproduce experimental object displacement with high accuracy via the simulated embodiment in the virtual world by feeding a spinal cord model with experimental registration of the cortical activity. Second, by using computational models of multiple granularities, our preliminary results show the possibility of simulating several features of the brain after stroke, from the local alteration in neuronal activity to long-range connectivity remodeling. Finally, strategies are proposed to merge the two pipelines. We further suggest that additional models could be integrated into the framework thanks to the versatility of the proposed approach, thus allowing many researchers to achieve continuously improved experimental design.

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