RESUMEN
Revealing unknown cues that regulate oligodendrocyte progenitor cell (OPC) function in remyelination is important to optimise the development of regenerative therapies for multiple sclerosis (MS). Platelets are present in chronic non-remyelinated lesions of MS and an increase in circulating platelets has been described in experimental autoimmune encephalomyelitis (EAE) mice, an animal model for MS. However, the contribution of platelets to remyelination remains unexplored. Here we show platelet aggregation in proximity to OPCs in areas of experimental demyelination. Partial depletion of circulating platelets impaired OPC differentiation and remyelination, without altering blood-brain barrier stability and neuroinflammation. Transient exposure to platelets enhanced OPC differentiation in vitro, whereas sustained exposure suppressed this effect. In a mouse model of thrombocytosis (Calr+/-), there was a sustained increase in platelet aggregation together with a reduction of newly-generated oligodendrocytes following toxin-induced demyelination. These findings reveal a complex bimodal contribution of platelet to remyelination and provide insights into remyelination failure in MS.
Asunto(s)
Plaquetas , Diferenciación Celular , Células Precursoras de Oligodendrocitos , Remielinización , Animales , Células Precursoras de Oligodendrocitos/fisiología , Remielinización/fisiología , Ratones , Plaquetas/fisiología , Encefalomielitis Autoinmune Experimental/patología , Ratones Endogámicos C57BL , Esclerosis Múltiple/patología , Modelos Animales de Enfermedad , Oligodendroglía/fisiología , FemeninoRESUMEN
Huntington's disease (HD) is a disease characterized by the progressive degeneration of nerve cells in the brain. DNA damage has been implicated in many neurological disorders; however, the association between this damage and the impaired signaling related to neurodegeneration is still unclear. The transcription factor c-AMP-responsive element binding protein (CREB) has a relevant role in the neuronal plasticity process regulating the expression of several genes, including brain-derived neurotrophic factor (BDNF). Here we analyzed the direct link between DNA damage and the expression of genes involved in neuronal plasticity. The study was performed in model cell lines STHdhQ7 (wild type) and STHdhQ111 (HD model). Treatment with Etoposide (Eto) was used to induce double-strand breaks (DSBs) to evaluate the DNA damage response (DDR) and the expression of synaptic plasticity genes. Eto treatment induced phosphorylation of ATM (p-ATM) and H2AX (γH2AX), markers of DDR, in both cell lines. Interestingly, upon DNA damage, STHdhQ7 cells showed increased expression of activity-regulated cytoskeleton associated protein (Arc) and BDNF when compared to the HD cell line model. Additionally, Eto induced CREB activation with a differential localization of its co-activators in the cell types analyzed. These results suggest that DSBs impact differentially the gene expression patterns of plasticity genes in the normal cell line versus the HD model. This effect is mediated by the impaired localization of CREB-binding protein (CBP) and histone acetylation in the HD model. Our results highlight the role of epigenetics and DNA repair on HD and therefore we suggest that future studies should explore in depth the epigenetic landscape on neuronal pathologies with the goal to further understand molecular mechanisms and pinpoint therapeutic targets.
Asunto(s)
Enfermedad de Huntington , Humanos , Enfermedad de Huntington/genética , Enfermedad de Huntington/metabolismo , Factor Neurotrófico Derivado del Encéfalo/genética , Daño del ADN , Transducción de Señal , Plasticidad NeuronalRESUMEN
Life expectancy in humans is increasing, resulting in a growing aging population, that is accompanied by an increased disposition to develop cognitive deterioration. Hypometabolism is one of the multiple factors related to inefficient brain function during aging. This review emphasizes the metabolic interactions between glial cells (astrocytes, oligodendrocytes, and microglia) and neurons, particularly, during aging. Glial cells provide support and protection to neurons allowing adequate synaptic activity. We address metabolic coupling from the expression of transporters, availability of substrates, metabolic pathways, and mitochondrial activity. In aging, the main metabolic exchange machinery is altered with inefficient levels of nutrients and detrimental mitochondrial activity that results in high reactive oxygen species levels and reduced ATP production, generating a highly inflammatory environment that favors deregulated cell death. Here, we provide an overview of the glial-to-neuron mechanisms, from the molecular components to the cell types, emphasizing aging as the crucial risk factor for developing neurodegenerative/neuroinflammatory diseases.
Asunto(s)
Neuroglía , Neuronas , Astrocitos/metabolismo , Encéfalo/metabolismo , Metabolismo Energético , Neuroglía/fisiología , Neuronas/metabolismoRESUMEN
OBJECTIVE: Currently, there are up to three different classifications for diagnosing septate uterus. The interobserver agreement among them has been poorly assessed. OBJECTIVE: To assess the interobserver agreement of nonexpert sonographers for classifying septate uterus using the European Society of Human Reproduction and Embryology/European Society for Gynaecological Endoscopy (ESHRE/ESGE), American Society for Reproductive Medicine (ASRM), and Congenital Uterine Malformations by Experts (CUME) classifications. METHODS: A total of 50 three-dimensional (3D) volumes of a nonconsecutive series of women with suspected uterine malformation were used. Two nonexpert examiners evaluated a single 3D volume of the uterus of each woman, blinded to each other. The following measurements were performed: indentation depth, indentation angle, uterine fundal wall thickness, external fundal indentation, and indentation-to-wall-thickness (I:WT) ratio. Each observer had to assign a diagnosis in each case, according to the three classification systems (ESHRE/ESGE, ASRM, and CUME). The interobserver agreement regarding the ESHRE/ESGE, ASRM, and CUME classifications was assessed using the Cohen weighted kappa index (k). Agreement regarding the three classifications (ASRM versus ESHRE/ESGE, ASRM versus CUME, ESHRE/ESGE versus CUME) was also assessed. RESULTS: The interobserver agreement between the 2 nonexpert examiners was good for the ESHRE/ESGE (k = 0.74; 95% confidence interval [CI]: 0.55-0.92) and very good for the ASRM and CUME classification systems (k = 0.95; 95%CI: 0.86-1.00; and k = 0.91; 95%CI: 0.79-1.00, respectively). Agreement between the ESHRE/ESGE and ASRM classifications was moderate for both examiners. Agreement between the ESHRE/ESGE and CUME classifications was moderate for examiner 1 and good for examiner 2. Agreement between the ASRM and CUME classifications was good for both examiners. CONCLUSION: The three classifications have good (ESHRE/ESGE) or very good (ASRM and CUME) interobserver agreement. Agreement between the ASRM and CUME classifications was higher than that for the ESHRE/ESGE and ASRM and ESHRE/ESGE and CUME classifications.
OBJETIVO: Atualmente, existem até três classificações diferentes para o diagnóstico de útero septado. A concordância interobservador entre eles tem sido pouco avaliada. OBJETIVO: Avaliar a concordância interobservador de ecografistas não especialistas para classificar úteros septados usando as classificações European Society of Human Reproduction and Embryology/European Society for Gynaecological Endoscopy (ESHRE/ESGE, na sigla em inglês), American Society for Reproductive Medicine (ASRM, na sigla em inglês) e Congenital Uterine Malformations by Experts (CUME, na sigla em inglês). MéTODOS: Foram utilizados 50 volumes tridimensionais (3D) de uma série não consecutiva de mulheres com suspeita de malformação uterina. Dois examinadores não especialistas avaliaram um único volume 3D do útero de cada mulher, mutuamente cegos. As seguintes medidas foram aferidas: profundidade de indentação, ângulo de indentação, espessura da parede do fundo uterino, indentação externa do fundo e relação entre indentação e a espessura da parede (I:WT, na sigla em inglês). Cada observador teve que atribuir um diagnóstico em cada caso, de acordo com os três sistemas de classificação (ESHRE/ESGE, ASRM e CUME). A concordância interobservador em relação às classificações ESHRE/ESGE, ASRM e CUME foi avaliada usando o índice kappa ponderado de Cohen (k). A concordância em relação às três classificações (ASRM versus ESHRE-ESGE, ASRM versus CUME e ESHRE-ESGE versus CUME) também foi avaliada. RESULTADOS: A concordância interobservador entre os 2 examinadores não especialistas foi boa para a classificação ESHRE/ESGE (k = 0,74, intervalo de confiança [IC] 95%: 0,550,92) e muito boa para os sistemas de classificação ASRM e CUME (k = 0,95; IC 95%: 0,861,00; e k = 0,91; IC95%: 0,791,00, respectivamente). A concordância entre as classificações ESHRE/ESGE e ASRM foi moderada para ambos os examinadores. A concordância entre as classificações ESHRE/ESGE e CUME foi moderada para o examinador 1 e boa para o examinador 2. A concordância entre as classificações ASRM e CUME foi boa para ambos os examinadores. CONCLUSãO: As três classificações apresentam concordância interobservador boa (ESHRE/ESGE) ou muito boa (ASRM e CUME). A concordância entre as classificações ASRM e CUME foi maior do que entre as classificações ESHRE/ESGE e ASRM e ESHRE/ESGE e CUME.
Asunto(s)
Anomalías Urogenitales , Útero , Femenino , Humanos , Variaciones Dependientes del Observador , Reproducibilidad de los Resultados , Ultrasonografía , Anomalías Urogenitales/diagnóstico por imagen , Útero/diagnóstico por imagenRESUMEN
Abstract Objective Currently, there are up to three different classifications for diagnosing septate uterus. The interobserver agreement among them has been poorly assessed. To assess the interobserver agreement of nonexpert sonographers for classifying septate uterus using the European Society of Human Reproduction and Embryology/European Society for Gynaecological Endoscopy (ESHRE/ESGE), American Society for Reproductive Medicine (ASRM), and Congenital Uterine Malformations by Experts (CUME) classifications. Methods A total of 50 three-dimensional (3D) volumes of a nonconsecutive series of women with suspected uterine malformation were used. Two nonexpert examiners evaluated a single 3D volume of the uterus of each woman, blinded to each other. The following measurements were performed: indentation depth, indentation angle, uterine fundal wall thickness, external fundal indentation, and indentation-to-wall-thickness (I:WT) ratio. Each observer had to assign a diagnosis in each case, according to the three classification systems (ESHRE/ESGE, ASRM, and CUME). The interobserver agreement regarding the ESHRE/ESGE, ASRM, and CUME classifications was assessed using the Cohen weighted kappa index (k). Agreement regarding the three classifications (ASRM versus ESHRE/ESGE, ASRM versus CUME, ESHRE/ESGE versus CUME) was also assessed. Results The interobserver agreement between the 2 nonexpert examiners was good for the ESHRE/ESGE (k = 0.74; 95% confidence interval [CI]: 0.55-0.92) and very good for the ASRM and CUME classification systems (k = 0.95; 95%CI: 0.86-1.00; and k = 0.91; 95%CI: 0.79-1.00, respectively). Agreement between the ESHRE/ESGE and ASRM classifications was moderate for both examiners. Agreement between the ESHRE/ESGE and CUME classifications was moderate for examiner 1 and good for examiner 2. Agreement between the ASRM and CUME classifications was good for both examiners. Conclusion The three classifications have good (ESHRE/ESGE) or very good (ASRM and CUME) interobserver agreement. Agreement between the ASRM and CUME classifications was higher than that for the ESHRE/ESGE and ASRM and ESHRE/ESGE and CUME classifications.
Resumo Objetivo Atualmente, existem até três classificações diferentes para o diagnóstico de útero septado. A concordância interobservador entre eles tem sido pouco avaliada. Avaliar a concordância interobservador de ecografistas não especialistas para classificar úteros septados usando as classificações European Society of Human Reproduction and Embryology/European Society for Gynaecological Endoscopy (ESHRE/ESGE, na sigla em inglês), American Society for Reproductive Medicine (ASRM, na sigla em inglês) e Congenital Uterine Malformations by Experts (CUME, na sigla em inglês). Métodos Foram utilizados50volumes tridimensionais (3D)deuma série não consecutiva de mulheres com suspeita de malformação uterina. Dois examinadores não especialistas avaliaram um único volume 3D do útero de cada mulher, mutuamente cegos. As seguintes medidas foram aferidas: profundidade de indentação, ângulo de indentação, espessura da parede do fundo uterino, indentação externa do fundo e relação entre indentação e a espessura da parede (I:WT, na sigla em inglês). Cada observador teve que atribuir um diagnóstico em cada caso, de acordo com os três sistemas de classificação (ESHRE/ESGE, ASRM e CUME). A concordância interobservador em relação às classificações ESHRE/ESGE, ASRM e CUME foi avaliada usando o índice kappa ponderado de Cohen (k). A concordância em relação às três classificações (ASRM versus ESHRE/ESGE, ASRM versus CUME e ESHRE/ ESGE versus CUME) também foi avaliada. Resultados A concordância interobservador entre os 2 examinadores não especialistas foi boa para a classificação ESHRE/ESGE (k = 0,74, intervalo de confiança [IC] 95%: 0,55-0,92) e muito boa para os sistemas de classificação ASRM e CUME (k = 0,95; IC 95%: 0,86-1,00; e k = 0,91; IC95%: 0,79-1,00, respectivamente). A concordância entre as classificações ESHRE/ESGE e ASRM foi moderada para ambos os examinadores. A concordância entre as classificações ESHRE/ESGE e CUME foi moderada para o examinador 1 e boa para o examinador 2. A concordância entre as classificações ASRM e CUME foi boa para ambos os examinadores. Conclusão As três classificações apresentam concordância interobservador boa (ESHRE/ESGE) ou muito boa (ASRM e CUME). A concordância entre as classificações ASRM e CUME foi maior do que entre as classificações ESHRE/ESGE e ASRM e ESHRE/ESGE e CUME.
Asunto(s)
Humanos , Femenino , Anomalías Urogenitales/diagnóstico por imagen , Útero/diagnóstico por imagen , Variaciones Dependientes del Observador , Reproducibilidad de los Resultados , UltrasonografíaRESUMEN
Clinical localization of primary tumors and sites of metastasis by PET is based on the enhanced cellular uptake of 2-deoxy-2-[18F]-fluoro-D-glucose (FDG). In prostate cancer, however, PET-FDG imaging has shown limited clinical applicability, suggesting that prostate cancer cells may utilize hexoses other than glucose, such as fructose, as the preferred energy source. Our previous studies suggested that prostate cancer cells overexpress fructose transporters, but not glucose transporters, compared with benign cells. Here, we focused on validating the functional expression of fructose transporters and determining whether fructose can modulate the biology of prostate cancer cells in vitro and in vivo. Fructose transporters, Glut5 and Glut9, were significantly upregulated in clinical specimens of prostate cancer when compared with their benign counterparts. Fructose levels in the serum of patients with prostate cancer were significantly higher than healthy subjects. Functional expression of fructose transporters was confirmed in prostate cancer cell lines. A detailed kinetic characterization indicated that Glut5 represents the main functional contributor in mediating fructose transport in prostate cancer cells. Fructose stimulated proliferation and invasion of prostate cancer cells in vitro. In addition, dietary fructose increased the growth of prostate cancer cell line-derived xenograft tumors and promoted prostate cancer cell proliferation in patient-derived xenografts. Gene set enrichment analysis confirmed that fructose stimulation enriched for proliferation-related pathways in prostate cancer cells. These results demonstrate that fructose promotes prostate cancer cell growth and aggressiveness in vitro and in vivo and may represent an alternative energy source for prostate cancer cells. SIGNIFICANCE: This study identifies increased expression of fructose transporters in prostate cancer and demonstrates a role for fructose as a key metabolic substrate supporting prostate cancer cells, revealing potential therapeutic targets and biomarkers.
Asunto(s)
Biomarcadores de Tumor/metabolismo , Dieta/efectos adversos , Fructosa/farmacología , Regulación Neoplásica de la Expresión Génica , Proteínas Facilitadoras del Transporte de la Glucosa/metabolismo , Transportador de Glucosa de Tipo 5/metabolismo , Neoplasias de la Próstata/patología , Animales , Apoptosis , Biomarcadores de Tumor/genética , Ciclo Celular , Movimiento Celular , Proliferación Celular , Proteínas Facilitadoras del Transporte de la Glucosa/genética , Transportador de Glucosa de Tipo 5/genética , Masculino , Ratones , Ratones Endogámicos NOD , Ratones SCID , Neoplasias de la Próstata/inducido químicamente , Neoplasias de la Próstata/genética , Neoplasias de la Próstata/metabolismo , Células Tumorales Cultivadas , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
Herpes simplex virus type 1 (HSV-1) is a widespread neurotropic virus. Primary infection of HSV-1 in facial epithelium leads to retrograde axonal transport to the central nervous system (CNS) where it establishes latency. Under stressful conditions, the virus reactivates, and new progeny are transported anterogradely to the primary site of infection. During the late stages of neuronal infection, axonal damage can occur, however, the impact of HSV-1 infection on the morphology and functional integrity of neuronal dendrites during the early stages of infection is unknown. We previously demonstrated that acute HSV-1 infection in neuronal cell lines selectively enhances Arc protein expression - a major regulator of long-term synaptic plasticity and memory consolidation, known for being a protein-interaction hub in the postsynaptic dendritic compartment. Thus, HSV-1 induced Arc expression may alter the functionality of infected neurons and negatively impact dendritic spine dynamics. In this study we demonstrated that HSV-1 infection induces structural disassembly and functional deregulation in cultured cortical neurons, an altered glutamate response, Arc accumulation within the somata, and decreased expression of spine scaffolding-like proteins such as PSD-95, Drebrin and CaMKIIß. However, whether these alterations are specific to the HSV-1 infection mechanism or reflect a secondary neurodegenerative process remains to be determined.
RESUMEN
Huntington's disease (HD) is a neurodegenerative disorder caused by a glutamine expansion at the first exon of the huntingtin gene. Huntingtin protein (Htt) is ubiquitously expressed and it is localized in several organelles, including endosomes. HD is associated with a failure in energy metabolism and oxidative damage. Ascorbic acid is a powerful antioxidant highly concentrated in the brain where it acts as a messenger, modulating neuronal metabolism. It is transported into neurons via the sodium-dependent vitamin C transporter 2 (SVCT2). During synaptic activity, ascorbic acid is released from glial reservoirs to the extracellular space, inducing an increase in SVCT2 localization at the plasma membrane. Here, we studied SVCT2 trafficking and localization in HD. SVCT2 is decreased at synaptic terminals in YAC128 male mice. Using cellular models for HD (STHdhQ7 and STHdhQ111 cells), we determined that SVCT2 trafficking through secretory and endosomal pathways is altered in resting conditions. We observed Golgi fragmentation and SVCT2/Htt-associated protein-1 mis-colocalization. Additionally, we observed altered ascorbic acid-induced calcium signaling that explains the reduced SVCT2 translocation to the plasma membrane in the presence of extracellular ascorbic acid (active conditions) described in our previous results. Therefore, SVCT2 trafficking to the plasma membrane is altered in resting and active conditions in HD, explaining the redox imbalance observed during early stages of the disease.
Asunto(s)
Enfermedad de Huntington/metabolismo , Transporte de Proteínas/fisiología , Transportadores de Sodio Acoplados a la Vitamina C/metabolismo , Sinaptosomas/metabolismo , Animales , Masculino , Ratones , Ratones Transgénicos , Neuronas/metabolismo , Oxidación-ReducciónRESUMEN
Despite the obvious personal relevance of some musical pieces, the cerebral mechanisms associated with listening to personally familiar music and its effects on subsequent brain functioning have not been specifically evaluated yet. We measured cerebral correlates with functional magnetic resonance imaging (fMRI) while composers listened to three types of musical excerpts varying in personal familiarity and self (familiar own/composition, familiar other/favorite or unfamiliar other/unknown music) followed by sequences of names of individuals also varying in personal familiarity and self (familiar own/own name, familiar other/close friend and unfamiliar other/unknown name). Listening to music with autobiographical contents (familiar own and/or other) recruited a fronto-parietal network including mainly the dorsolateral prefrontal cortex, the supramarginal/angular gyri and the precuneus. Additionally, while listening to familiar other music (favorite) was associated with the activation of reward and emotion networks (e.g. the striatum), familiar own music (compositions) engaged brain regions underpinning self-reference (e.g. the medial prefrontal cortex) and visuo-motor imagery. The present findings further suggested that familiar music with self-related reference (compositions) leads to an enhanced activation of the autobiographical network during subsequent familiar name processing (as compared to music without self-related reference); among these structures, the precuneus seems to play a central role in personally familiar processing.
Asunto(s)
Percepción Auditiva , Corteza Prefrontal/fisiología , Reconocimiento en Psicología , Adulto , Mapeo Encefálico , Emociones/fisiología , Femenino , Humanos , Masculino , Música , Nombres , Adulto JovenRESUMEN
Small-molecule fluorescent wheat germ agglutinin (WGA) conjugates are routinely used to demarcate mammalian plasma membranes, because they bind to the cell's glycocalyx. Here, we describe the derivatization of WGA with a pH-sensitive rhodamine fluorophore (pHRho; pKa = 7) to detect proton channel fluxes and extracellular proton accumulation and depletion from primary cells. We found that WGA-pHRho labeling was uniform and did not appreciably alter the voltage gating of glycosylated ion channels, and the extracellular changes in pH correlated with proton channel activity. Using single-plane illumination techniques, WGA-pHRho was used to detect spatiotemporal differences in proton accumulation and depletion over the extracellular surface of cardiomyocytes, astrocytes, and neurons. Because WGA can be derivatized with any small-molecule fluorescent ion sensor, WGA conjugates should prove useful to visualize most electrogenic and nonelectrogenic events on the extracellular side of the plasma membrane.
Asunto(s)
Membrana Celular/química , Protones , Aglutininas del Germen de Trigo/química , Animales , Glicosilación , Concentración de Iones de HidrógenoRESUMEN
The average life expectancy for humans has increased over the last years. However, the quality of the later stages of life is low and is considered a public health issue of global importance. Late adulthood and the transition into the later stage of life occasionally leads to neurodegenerative diseases that selectively affect different types of neurons and brain regions, producing motor dysfunctions, cognitive impairment, and psychiatric disorders that are progressive, irreversible, without remission periods, and incurable. Huntington's disease (HD) is a common neurodegenerative disorder. In the 25 years since the mutation of the huntingtin (HTT) gene was identified as the molecule responsible for this neural disorder, a variety of animal models, including the fruit fly, have been used to study the disease. Here, we review recent research that used Drosophila as an experimental tool for improving knowledge about the molecular and cellular mechanisms underpinning HD.
Asunto(s)
Enfermedad de Huntington/genética , Enfermedad de Huntington/metabolismo , Enfermedad de Huntington/fisiopatología , Animales , Modelos Animales de Enfermedad , Drosophila melanogaster , Humanos , Enfermedad de Huntington/patologíaRESUMEN
Collagen, the most abundant component in mammalian tissues, has a crucial impact at skin level. Both promotion and maintenance of cross-linked collagen at the skin are critical to sustain the functionality and appearance of that tissue. Lysyl oxidases, also known as LOX enzymes, are the major collagen cross-linking enzymes that play a pivotal role in homeostasis. This minireview summarizes evidence that describes an amino oxidase-like activity, which could be attributed to polyphenols, or where polyphenols could be required. We also discuss some available collagen formulations and the scientific evidence that describes the impact on dermal extracellular matrix. In addition, information about encapsulation strategies to carry polyphenols, and some examples are also provided.
Asunto(s)
Colágeno , Polifenoles , Piel , Aminoácido Oxidorreductasas , Animales , Humanos , Estructura MolecularRESUMEN
γ-Aminobutyric acid (GABA), plays a key role in all stages of life, also is considered the main inhibitory neurotransmitter. GABA activates two kind of membrane receptors known as GABAA and GABAB, the first one is responsible to render tonic inhibition by pentameric receptors containing α4-6, ß3, δ, or ρ1-3 subunits, they are located at perisynaptic and/or in extrasynaptic regions. The biophysical properties of GABAA tonic inhibition have been related with cellular protection against excitotoxic injury and cell death in presence of excessive excitation. On this basis, GABAA tonic inhibition has been proposed as a potential target for therapeutic intervention of Huntington's disease. Huntington's disease is a neurodegenerative disorder caused by a genetic mutation of the huntingtin protein. For experimental studies of Huntington's disease mouse models have been developed, such as R6/1, R6/2, HdhQ92, HdhQ150, as well as YAC128. In all of them, some key experimental reports are focused on neostriatum. The neostriatum is considered as the most important connection between cerebral cortex and basal ganglia structures, its cytology display two pathways called direct and indirect constituted by medium sized spiny neurons expressing dopamine D1 and D2 receptors respectively, they display strong expression of many types of GABAA receptors, including tonic subunits. The studies about of GABAA tonic subunits and Huntington's disease into the neostriatum are rising in recent years, suggesting interesting changes in their expression and localization which can be used as a strategy to delay the cellular damage caused by the imbalance between excitation and inhibition, a hallmark of Huntington's disease.
RESUMEN
AIMS: Huntington's disease (HD) is a neurodegenerative disorder characterized by progressive abnormalities in cognitive function, mental state, and motor control. HD is characterized by a failure in brain energy metabolism. It has been proposed that monocarboxylates, such as lactate, support brain activity. During neuronal synaptic activity, ascorbic acid released from glial cells stimulates lactate and inhibits glucose transport. The aim of this study was to evaluate the expression and function of monocarboxylate transporters (MCTs) in two HD models. METHODS: Using immunofluorescence, qPCR, and Western blot analyses, we explored mRNA and protein levels of MCTs in the striatum of R6/2 animals and HdhQ7/111 cells. We also evaluated MCT function in HdhQ7/111 cells using radioactive tracers and the fluorescent lactate sensor Laconic. RESULTS: We found no significant differences in the mRNA or protein levels of neuronal MCTs. Functional analyses revealed that neuronal MCT2 had a high catalytic efficiency in HD cells. Ascorbic acid did not stimulate lactate uptake in HD cells. Ascorbic acid was also unable to inhibit glucose transport in HD cells because they exhibit decreased expression of the neuronal glucose transporter GLUT3. CONCLUSION: We demonstrate that stimulation of lactate uptake by ascorbic acid is a consequence of inhibiting glucose transport. Supporting this, lactate transport stimulation by ascorbic acid in HD cells was completely restored by overexpressing GLUT3. Therefore, alterations in GLUT3 expression could be responsible for inefficient use of lactate in HD neurons, contributing to the metabolic failure observed in HD.
Asunto(s)
Transportador de Glucosa de Tipo 3/metabolismo , Enfermedad de Huntington/metabolismo , Ácido Láctico/metabolismo , Animales , Línea Celular , Cuerpo Estriado/metabolismo , Modelos Animales de Enfermedad , Femenino , Humanos , Masculino , Ratones Transgénicos , Transportadores de Ácidos Monocarboxílicos/metabolismo , Neuronas/metabolismo , ARN Mensajero/metabolismo , RatasRESUMEN
GABA is a widely distributed inhibitory neurotransmitter. GABA-A receptors are hetero-pentameric channels assembled in multiple combinations from 19 available subunits; this diversity mediates phasic and tonic inhibitory synaptic potentials. Whereas GABA-A phasic receptors are located within the synaptic cleft, GABA-A tonic receptors are found peri- or extra-synaptically, where they are activated by diffusion of synaptic GABA release. In the neostriatum, GABA-A tonic subunits are present in the D2 medium-size spiny neurons. Since early impairment of these neurons is observed in Huntington's disease, we determined the ultrastructural localization of GABA-A-α5, -ß3, -δ, -ρ2 and, for the first time, of GABA-A-ρ3 subunits, in the D2 pathway of the YAC128 murine model of Huntington's disease at various stages of disease progression. We report mislocalization of all five subunits from peri- and extra-synaptic spaces into the synaptic clefts of YAC128 mice, present in diseased mice as early as 6 months-old. The synaptic localization of GABA-A tonic receptors correlated with increased sensitivity to pharmacologic antagonists during extracellular electrophysiological recordings in neostriatal slices. Finally, the association of GABA-A tonic receptors with the D2 pathway in 6-month-old mice was largely lost at 12 months of age.
Asunto(s)
Neuronas GABAérgicas/metabolismo , Enfermedad de Huntington/metabolismo , Receptores de GABA-A/metabolismo , Animales , Neuronas GABAérgicas/patología , Neuronas GABAérgicas/ultraestructura , Humanos , Enfermedad de Huntington/patología , Ratones , Ratones Transgénicos , Neostriado/metabolismo , Neostriado/patología , Sinapsis/metabolismoRESUMEN
OBJECTIVE: Two recent important lupus nephritis trials reported that proteinuria was a good predictor of renal outcome in Caucasians, but data on real-life situation, other races and severe nephritis are lacking to substantiate this finding as a simple test to guide clinical practice. The aim of this study was to validate proteinuria as a predictor of long-term renal outcome in real-life situation in a racially diverse group of patients with severe nephritis. METHODS: Proteinuria, serum creatinine (SCr) and urine red blood cells were assessed at baseline and after 3, 6 and 12 months, as early predictors of long-term renal outcome (SCr <1.5 mg/dL at 7 years), in 94 patients with biopsy-proven lupus nephritis. The parameter performance and cut-off values were computed by receiver operating characteristic curves. Kaplan-Meier curves were used to validate the parameter. RESULTS: A proteinuria <0.8 g/24 hours at 12 months was the best single predictor of long-term renal outcome (sensitivity 90%, specificity 78%, positive predictive value 67%, negative predictive value (NPV) 94% and area under the curve 0.86; p<0.001). Addition of other variables to proteinuria such as SCr and haematuria at 12 months did not improve its performance. The proteinuria cut-off value of 0.8 g/24 hours at 12 months was a good predictor of 7-year renal survival (years free of dialysis) for patients with pure membranous (p=0.005) and proliferative nephritis (p=0.043), as well as black (p=0.002) and white race (p=0.001), anti-dsDNA positive (p=0.001) and anti-dsDNA negative (p=0.04) and male (p=0.028) and female (p=0.003) patients. CONCLUSION: We provided novel evidence that, in a real-life situation, proteinuria at 12 months of follow-up was the single best predictor of renal outcome at 7 years for an ethnically diverse group of patients with severe nephritis and a valid parameter for distinct histological classes, races, genders and anti-dsDNA profiles. The remarkably high NPV obtained reinforces its recommendation as the ideal predictor for clinical practice, since it is of low cost, easy to interpret, non-invasive and widely available.
RESUMEN
Immunolocalization techniques are standard in biomedical research. Tissue fixation with aldehydes and cell membrane permeabilization with detergents can distort the specific binding of antibodies to their high affinity epitopes. In immunofluorescence protocols, it is desirable to quench the sample's autofluorescence without reduction of the antibody-dependent signal. Here we show that adding glycine to the blocking buffer and diluting the antibodies in a phosphate saline solution containing glycine, Triton X-100, Tween20 and hydrogen peroxide increase the specific antibody signal in tissue immunofluorescence and immunogold electron microscopy. This defined antibody signal enhancer (ASE) solution gives similar results to the commercially available Pierce Immunostain Enhancer (PIE). Furthermore, prolonged tissue incubation in resin and fixative and application of ASE or PIE are described in an improved protocol for triple immunogold electron microscopy that is used to show co-localization of GABA-A ρ2 and dopamine D2 receptors in GFAP-positive astrocytes in the mouse striatum. The addition of glycine, Triton X-100, Tween20 and hydrogen peroxide during antibody incubation steps is recommended in immunohistochemistry methods.
Asunto(s)
Anticuerpos/análisis , Técnica del Anticuerpo Fluorescente/métodos , Microscopía Inmunoelectrónica/métodos , Animales , Anticuerpos/inmunología , Ratones , Ratones Endogámicos C57BLRESUMEN
Ascorbic acid is a key antioxidant of the Central Nervous System (CNS). Under brain activity, ascorbic acid is released from glial reservoirs to the synaptic cleft, where it is taken up by neurons. In neurons, ascorbic acid scavenges reactive oxygen species (ROS) generated during synaptic activity and neuronal metabolism where it is then oxidized to dehydroascorbic acid and released into the extracellular space, where it can be recycled by astrocytes. Other intrinsic properties of ascorbic acid, beyond acting as an antioxidant, are important in its role as a key molecule of the CNS. Ascorbic acid can switch neuronal metabolism from glucose consumption to uptake and use of lactate as a metabolic substrate to sustain synaptic activity. Multiple evidence links oxidative stress with neurodegeneration, positioning redox imbalance and ROS as a cause of neurodegeneration. In this review, we focus on ascorbic acid homeostasis, its functions, how it is used by neurons and recycled to ensure antioxidant supply during synaptic activity and how this antioxidant is dysregulated in neurodegenerative disorders.
Asunto(s)
Ácido Ascórbico/metabolismo , Encéfalo/metabolismo , Enfermedades Neurodegenerativas/metabolismo , Fármacos Neuroprotectores/metabolismo , Animales , Antioxidantes/metabolismo , Astrocitos/metabolismo , Encéfalo/patología , Sistema Nervioso Central/metabolismo , Sistema Nervioso Central/patología , Metabolismo Energético , Humanos , Enfermedades Neurodegenerativas/patología , Neuronas/metabolismo , Oxidación-Reducción , Estrés Oxidativo , Especies Reactivas de Oxígeno/metabolismo , Sinapsis/metabolismoRESUMEN
Preferred music is a highly emotional and salient stimulus, which has previously been shown to increase the probability of auditory cognitive event-related responses in patients with disorders of consciousness (DOC). To further investigate whether and how music modifies the functional connectivity of the brain in DOC, five patients were assessed with both a classical functional connectivity scan (control condition), and a scan while they were exposed to their preferred music (music condition). Seed-based functional connectivity (left or right primary auditory cortex), and mean network connectivity of three networks linked to conscious sound perception were assessed. The auditory network showed stronger functional connectivity with the left precentral gyrus and the left dorsolateral prefrontal cortex during music as compared to the control condition. Furthermore, functional connectivity of the external network was enhanced during the music condition in the temporo-parietal junction. Although caution should be taken due to small sample size, these results suggest that preferred music exposure might have effects on patients auditory network (implied in rhythm and music perception) and on cerebral regions linked to autobiographical memory.
RESUMEN
Failure in energy metabolism and oxidative damage are associated with Huntington's disease (HD). Ascorbic acid released during synaptic activity inhibits use of neuronal glucose, favouring lactate uptake to sustain brain activity. Here, we observe a decreased expression of GLUT3 in STHdhQ111 cells (HD cells) and R6/2 mice (HD mice). Localisation of GLUT3 is decreased at the plasma membrane in HD cells affecting the modulation of glucose uptake by ascorbic acid. An ascorbic acid analogue without antioxidant activity is able to inhibit glucose uptake in HD cells. The impaired modulation of glucose uptake by ascorbic acid is directly related to ROS levels indicating that oxidative stress sequesters the ability of ascorbic acid to modulate glucose utilisation. Therefore, in HD, a decrease in GLUT3 localisation at the plasma membrane would contribute to an altered neuronal glucose uptake during resting periods while redox imbalance should contribute to metabolic failure during synaptic activity.