RESUMEN
The Zika virus (ZIKV) epidemic declared in Brazil between 2015 and 2016 was associated with an increased prevalence of severe congenital malformations, including microcephaly. The distribution of microcephaly cases was not uniform across the country, with a disproportionately higher incidence in the Northeast region (NE). Our previous work demonstrated that saxitoxin (STX), a toxin present in the drinking water reservoirs of the NE, exacerbated the damaging effects of ZIKV on the developing brain. We hypothesized that the impact of STX might vary among different neural cell types. While ZIKV infection caused severe damages on astrocytes and neural stem cells (NSCs), the addition of STX did not exacerbate these effects. We observed that neurons subjected to STX exposure were more prone to apoptosis and displayed higher ZIKV infection rate. These findings suggest that STX exacerbates the harmful effects of ZIKV on neurons, thereby providing a plausible explanation for the heightened severity of ZIKV-induced congenital malformations observed in Brazil's NE. This study highlights the importance of understanding the interactive effects of environmental toxins and infectious pathogens on neural development, with potential implications for public health policies.
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Astrocitos , Células-Madre Neurales , Neuronas , Saxitoxina , Infección por el Virus Zika , Virus Zika , Células-Madre Neurales/virología , Células-Madre Neurales/efectos de los fármacos , Células-Madre Neurales/metabolismo , Humanos , Virus Zika/fisiología , Astrocitos/virología , Astrocitos/efectos de los fármacos , Astrocitos/metabolismo , Neuronas/virología , Neuronas/efectos de los fármacos , Neuronas/metabolismo , Infección por el Virus Zika/virología , Infección por el Virus Zika/patología , Saxitoxina/toxicidad , Apoptosis/efectos de los fármacos , Microcefalia/virología , Muerte Celular/efectos de los fármacos , Brasil , Células CultivadasRESUMEN
Agathisflavone is a flavonoid that exhibits anti-inflammatory and anti-oxidative properties. Here, we investigated the neuroprotective effects of agathisflavone on central nervous system (CNS) neurons and glia in the cerebellar slice ex vivo model of neonatal ischemia. Cerebellar slices from neonatal mice, in which glial fibrillary acidic protein (GFAP) and SOX10 drive expression of enhanced green fluorescent protein (EGFP), were used to identify astrocytes and oligodendrocytes, respectively. Agathisflavone (10 µM) was administered preventively for 60 min before inducing ischemia by oxygen and glucose deprivation (OGD) for 60 min and compared to controls maintained in normal oxygen and glucose (OGN). The density of SOX-10+ oligodendrocyte lineage cells and NG2 immunopositive oligodendrocyte progenitor cells (OPCs) were not altered in OGD, but it resulted in significant oligodendroglial cell atrophy marked by the retraction of their processes, and this was prevented by agathisflavone. OGD caused marked axonal demyelination, determined by myelin basic protein (MBP) and neurofilament (NF70) immunofluorescence, and this was blocked by agathisflavone preventative treatment. OGD also resulted in astrocyte reactivity, exhibited by increased GFAP-EGFP fluorescence and decreased expression of glutamate synthetase (GS), and this was prevented by agathisflavone pretreatment. In addition, agathisflavone protected Purkinje neurons from ischemic damage, assessed by calbindin (CB) immunofluorescence. The results demonstrate that agathisflavone protects neuronal and myelin integrity in ischemia, which is associated with the modulation of glial responses in the face of ischemic damage.
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Animales Recién Nacidos , Cerebelo , Flavonoides , Fármacos Neuroprotectores , Animales , Fármacos Neuroprotectores/farmacología , Ratones , Cerebelo/metabolismo , Cerebelo/efectos de los fármacos , Flavonoides/farmacología , Oligodendroglía/efectos de los fármacos , Oligodendroglía/metabolismo , Astrocitos/efectos de los fármacos , Astrocitos/metabolismo , Isquemia Encefálica/tratamiento farmacológico , Isquemia Encefálica/metabolismo , Isquemia Encefálica/patología , Neuronas/efectos de los fármacos , Neuronas/metabolismo , Glucosa/metabolismo , BiflavonoidesRESUMEN
Autism spectrum disorder (ASD) is known as a group of neurodevelopmental conditions including stereotyped and repetitive behaviors, besides social and sensorimotor deficits. Anatomical and functional evidence indicates atypical maturation of the striatum. Astrocytes regulate the maturation and plasticity of synaptic circuits, and impaired calcium signaling is associated with repetitive behaviors and atypical social interaction. Spontaneous calcium transients (SCT) recorded in the striatal astrocytes of the rat were investigated in the preclinical model of ASD by prenatal exposure to valproic acid (VPA). Our results showed sensorimotor delay, augmented glial fibrillary acidic protein -a typical intermediate filament protein expressed by astrocytes- and diminished expression of GABAA-ρ3 through development, and increased frequency of SCT with a reduced latency that resulted in a diminished amplitude in the VPA model. The convulsant picrotoxin, a GABAA (γ-aminobutyric acid type A) receptor antagonist, reduced the frequency of SCT in both experimental groups but rescued this parameter to control levels in the preclinical ASD model. The amplitude and latency of SCT were decreased by picrotoxin in both experimental groups. Nipecotic acid, a GABA uptake inhibitor, reduced the mean amplitude only for the control group. Nevertheless, nipecotic acid increased the frequency but diminished the latency in both experimental groups. Thus, we conclude that striatal astrocytes exhibit SCT modulated by GABAA-mediated signaling, and prenatal exposure to VPA disturbs this tuning.
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Astrocitos , Cuerpo Estriado , Animales , Astrocitos/metabolismo , Astrocitos/efectos de los fármacos , Cuerpo Estriado/metabolismo , Cuerpo Estriado/efectos de los fármacos , Femenino , Embarazo , Ratas , Ácido Valproico/farmacología , Ratas Wistar , Picrotoxina/farmacología , Señalización del Calcio/efectos de los fármacos , Señalización del Calcio/fisiología , Modelos Animales de Enfermedad , Masculino , Calcio/metabolismo , Trastorno del Espectro Autista/metabolismo , Trastorno Autístico/metabolismo , Efectos Tardíos de la Exposición Prenatal/metabolismoRESUMEN
There is a public health concern about the use of methylphenidate (MPH) since the higher prescription for young individuals and non-clinical purposes is addressed to the limited understanding of its neurochemical and psychiatric consequences. This study aimed to evaluate the impact of early and chronic MPH treatment on the striatum focusing on amino acid profile, glutamatergic excitotoxicity, redox status, neuroinflammation and glial cell responses. Male Wistar rats were treated with MPH (2.0 mg/kg) or saline solution from the 15th to the 44th postnatal day. Biochemical and histological analyses were conducted after the last administration. MPH altered the amino acid profile in the striatum, increasing glutamate and ornithine levels, while decreasing the levels of serine, phenylalanine, and branched-chain amino acids (leucine, valine, and isoleucine). Glutamate uptake and Na+,K+-ATPase activity were decreased in the striatum of MPH-treated rats as well as increased ATP levels, as indicator of glutamatergic excitotoxicity. Moreover, MPH caused lipid peroxidation and nitrative stress, increased TNF alpha expression, and induced high levels of astrocytes, and led to a decrease in BDNF levels. In summary, our results suggest that chronic early-age treatment with MPH induces parallel activation of damage-associated pathways in the striatum and increases its vulnerability during the juvenile period. In addition, data presented here contribute to shedding light on the mechanisms underlying MPH-induced striatal damage and its potential implications for neurodevelopmental disorders.
Asunto(s)
Aminoácidos , Astrocitos , Estimulantes del Sistema Nervioso Central , Cuerpo Estriado , Ácido Glutámico , Metilfenidato , Ratas Wistar , Animales , Masculino , Cuerpo Estriado/efectos de los fármacos , Cuerpo Estriado/metabolismo , Astrocitos/efectos de los fármacos , Astrocitos/metabolismo , Metilfenidato/toxicidad , Metilfenidato/farmacología , Ácido Glutámico/metabolismo , Ratas , Estimulantes del Sistema Nervioso Central/toxicidad , Estimulantes del Sistema Nervioso Central/farmacología , Aminoácidos/metabolismo , Peroxidación de Lípido/efectos de los fármacosRESUMEN
Glutamate is involved in fundamental functions, including neuronal plasticity and memory. Astrocytes are integral elements involved in synaptic function, and the GLT-1 transporter possesses a critical role in glutamate uptake. Here, we study the role of GLT-1, specifically located in astrocytes, in the consolidation, expression, reconsolidation and persistence of spatial object recognition memory in rats. Administration of dihydrokainic acid (DHK), a selective GLT-1 inhibitor, into the dorsal hippocampus around a weak training which only induces short-term memory, promotes long-term memory formation. This promotion is prevented by hippocampal administration of protein-synthesis translation inhibitor, blockade of Activity-regulated cytoskeleton-associated protein (Arc) translation or Brain-Derived Neurotrophic Factor (BDNF) action, which are plasticity related proteins necessary for memory consolidation. However, DHK around a strong training, which induces long-term memory, does not affect memory consolidation. Administration of DHK before the test session impairs the expression of long-term memory, and this effect is dependent of Arc translation. Furthermore, DHK impairs reconsolidation if applied before a reactivation session, and this effect is independent of Arc translation. These findings reveal specific consequences on spatial memory stages developed under hippocampal GLT-1 blockade, shedding light on the intricate molecular mechanisms, governed in part for the action of glia.
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Astrocitos , Factor Neurotrófico Derivado del Encéfalo , Proteínas del Citoesqueleto , Ácido Glutámico , Hipocampo , Memoria Espacial , Animales , Hipocampo/efectos de los fármacos , Hipocampo/metabolismo , Hipocampo/fisiología , Astrocitos/efectos de los fármacos , Astrocitos/metabolismo , Memoria Espacial/efectos de los fármacos , Factor Neurotrófico Derivado del Encéfalo/metabolismo , Masculino , Ratas , Proteínas del Citoesqueleto/metabolismo , Proteínas del Citoesqueleto/genética , Ácido Glutámico/metabolismo , Proteínas del Tejido Nervioso/metabolismo , Proteínas del Tejido Nervioso/antagonistas & inhibidores , Proteínas del Tejido Nervioso/genética , Transportador 2 de Aminoácidos Excitadores/metabolismo , Transportador 2 de Aminoácidos Excitadores/antagonistas & inhibidores , Ratas Wistar , Ácido Kaínico/farmacología , Ácido Kaínico/análogos & derivados , Consolidación de la Memoria/efectos de los fármacosRESUMEN
There is evidence that astrocytes modulate synaptic transmission in the nucleus tractus solitarius (NTS) interacting with glutamatergic and purinergic mechanisms. Here, using in situ working heart-brainstem preparations, we evaluated the involvement of astrocyte and glutamatergic/purinergic neurotransmission in the processing of autonomic and respiratory pathways in the NTS of control and rats exposed to sustained hypoxia (SH). Baseline autonomic and respiratory activities and the responses to chemoreflex activation (KCN) were evaluated before and after microinjections of fluorocitrate (FCt, an astrocyte metabolic inhibitor), kynurenic acid, and pyridoxalphosphate-6-azophenyl-2',4'-disulfonate (PPADS) (nonselective antagonists of glutamatergic and purinergic receptors) into the rostral aspect of the caudal commissural NTS. FCt had no effects on the baseline parameters evaluated but reduced the bradycardic response to chemoreflex activation in SH rats. FCt combined with kynurenic acid and PPADS in control rats reduced the baseline duration of expiration, which was attenuated after SH. FCt produced a large increase in PN frequency discharge in control rats, which was reduced after SH, indicating a reduction in the astrocyte modulation after SH. The data show that 1) the bradycardic component of the peripheral chemoreflex is reduced in SH rats after astrocytes inhibition, 2) the inhibition of astrocytes in the presence of double antagonists in the NTS affects the modulation of baseline duration of expiration in control but not in SH rats, and 3) the autonomic and respiratory responses to chemoreflex activation are mediated by glutamatergic and purinergic receptors in the rostral aspect of the caudal commissural NTS.NEW & NOTEWORTHY Our findings indicate that the neurotransmission of autonomic and respiratory components of the peripheral chemoreflex in the nucleus tractus solitarius (NTS) is mediated by glutamatergic and purinergic mechanisms and reveal a selective involvement of NTS astrocytes in controlling the chemoreflex parasympathetic response in rats exposed to sustained hypoxia (SH) and the baseline duration of expiration mainly in control rats, indicating a selective role for astrocytes modulation in the NTS of control and SH rats.
Asunto(s)
Astrocitos , Ácido Glutámico , Hipoxia , Receptores Purinérgicos , Núcleo Solitario , Transmisión Sináptica , Animales , Núcleo Solitario/metabolismo , Núcleo Solitario/efectos de los fármacos , Astrocitos/metabolismo , Astrocitos/efectos de los fármacos , Transmisión Sináptica/efectos de los fármacos , Transmisión Sináptica/fisiología , Hipoxia/fisiopatología , Hipoxia/metabolismo , Masculino , Ácido Glutámico/metabolismo , Receptores Purinérgicos/metabolismo , Ratas , Ratas Wistar , Ácido Quinurénico/farmacología , Células Quimiorreceptoras/metabolismo , Células Quimiorreceptoras/efectos de los fármacos , Antagonistas de Aminoácidos Excitadores/farmacología , Fosfato de Piridoxal/análogos & derivados , Fosfato de Piridoxal/farmacología , Citratos/farmacología , Factores de TiempoRESUMEN
BACKGROUND AND PURPOSE: Inhibitors of histone deacetylases (iHDACs) are promising drugs for neurodegenerative diseases. We have evaluated the therapeutic potential of the new iHDAC LASSBio-1911 in Aß oligomer (AßO) toxicity models and astrocytes, key players in neuroinflammation and Alzheimer's disease (AD). EXPERIMENTAL APPROACH: Astrocyte phenotype and synapse density were evaluated by flow cytometry, Western blotting, immunofluorescence and qPCR, in vitro and in mice. Cognitive function was evaluated by behavioural assays using a mouse model of intracerebroventricular infusion of AßO. KEY RESULTS: LASSBio-1911 modulates reactivity and synaptogenic potential of cultured astrocytes and improves synaptic markers in cultured neurons and in mice. It prevents AßO-triggered astrocytic reactivity in mice and enhances the neuroprotective potential of astrocytes. LASSBio-1911 improves behavioural performance and rescues synaptic and memory function in AßO-infused mice. CONCLUSION AND IMPLICATIONS: These results contribute to unveiling the mechanisms underlying astrocyte role in AD and provide the rationale for using astrocytes as targets to new drugs for AD.
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Péptidos beta-Amiloides , Astrocitos , Disfunción Cognitiva , Inhibidores de Histona Desacetilasas , Animales , Astrocitos/efectos de los fármacos , Astrocitos/metabolismo , Péptidos beta-Amiloides/metabolismo , Péptidos beta-Amiloides/toxicidad , Inhibidores de Histona Desacetilasas/farmacología , Ratones , Disfunción Cognitiva/tratamiento farmacológico , Disfunción Cognitiva/metabolismo , Disfunción Cognitiva/inducido químicamente , Masculino , Ratones Endogámicos C57BL , Células Cultivadas , Sinapsis/efectos de los fármacos , Sinapsis/metabolismo , Fármacos Neuroprotectores/farmacología , Fármacos Neuroprotectores/administración & dosificaciónRESUMEN
Astrocytes provide metabolic support to neurons, maintain ionic and water homeostasis, and uptake and recycle neurotransmitters. After exposure to the prototypical PAMP lipopolysaccharide (LPS), reactive astrocytes increase the expression of pro-inflammatory genes, facilitating neurodegeneration. In this study, we analyzed the expression of homeostatic genes in astrocytes exposed to LPS and identified the epigenetic factors contributing to the suppression of homeostatic genes in reactive astrocytes. Primary astrocytic cultures were acutely exposed to LPS and allowed to recover for 24, 72 h, and 7 days. As expected, LPS exposure induced reactive astrogliosis and increased the expression of pro-inflammatory IL-1B and IL-6. Interestingly, the acute exposure resulted in persistent hypermethylation of astroglial DNA. Similar hypermethylation was observed in highly reactive astrocytes from the traumatic brain injury (TBI) penumbra in vivo. Hypermethylation was accompanied by decreased expression of homeostatic genes including LDHA and Scl16a1 (MCT1) both involved in the lactate shuttle to neurons; glutamine synthase (GS) responsible for glutamate processing; Kcnj10 (Kir4.1) important for K+ homeostasis, and the water channel aquaporin-4 (Aqp4). Furthermore, the master regulator of DNA methylation, MAFG-1, as well as DNA methyl transferases DNMT1 and DNMT3a were overexpressed. The downregulation of homeostatic genes correlated with increased methylation of CpG islands in their promoters, as assessed by methylation-sensitive PCR and increased DNMT3a binding to the GS promoter. Treatment with decitabine, a DNMT inhibitor, prevented the LPS- and the HMGB-1-induced downregulation of homeostatic genes. Decitabine treatment also prevented the neurotoxic effects of these astrocytes in primary cortical cultures. In summary, our findings reveal that the pathological remodeling of reactive astrocytes encompasses not only the pro-inflammatory response but, significantly, also entails a long-term suppression of homeostatic gene expression with methylation of crucial CpG islands within their promoters.
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Astrocitos , Metilación de ADN , Regulación hacia Abajo , Homeostasis , Astrocitos/metabolismo , Astrocitos/efectos de los fármacos , Astrocitos/patología , Metilación de ADN/efectos de los fármacos , Animales , Homeostasis/efectos de los fármacos , Regulación hacia Abajo/efectos de los fármacos , Células Cultivadas , Lipopolisacáridos/farmacología , Masculino , Ratones , Lesiones Traumáticas del Encéfalo/patología , Lesiones Traumáticas del Encéfalo/metabolismo , Lesiones Traumáticas del Encéfalo/genética , Ratas , Ratones Endogámicos C57BLRESUMEN
Sulforaphane is a natural compound with neuroprotective activity, but its effects on hypothalamus remain unknown. In line with this, astrocytes are critical cells to maintain brain homeostasis, and hypothalamic astrocytes are fundamental for sensing and responding to environmental changes involved in a variety of homeostatic functions. Changes in brain functionality, particularly associated with hypothalamic astrocytes, can contribute to age-related neurochemical alterations and, consequently, neurodegenerative diseases. Thus, here, we investigated the glioprotective effects of sulforaphane on hypothalamic astrocyte cultures and hypothalamic cell suspension obtained from aged Wistar rats (24 months old). Sulforaphane showed anti-inflammatory and antioxidant properties, as well as modulated the mRNA expression of astroglial markers, such as aldehyde dehydrogenase 1 family member L1, aquaporin 4, and vascular endothelial growth factor. In addition, it increased the expression and extracellular levels of trophic factors, such as glia-derived neurotrophic factor and nerve growth factor, as well as the release of brain-derived neurotrophic factor and the mRNA of TrkA, which is a receptor associated with trophic factors. Sulforaphane also modulated the expression of classical pathways associated with glioprotection, including nuclear factor erythroid-derived 2-like 2, heme oxygenase-1, nuclear factor kappa B p65 subunit, and AMP-activated protein kinase. Finally, a cell suspension with neurons and glial cells was used to confirm the predominant effect of sulforaphane in glial cells. In summary, this study indicated the anti-aging and glioprotective activities of sulforaphane in aged astrocytes.
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Envejecimiento , Astrocitos , Hipotálamo , Isotiocianatos , Fármacos Neuroprotectores , Ratas Wistar , Sulfóxidos , Animales , Isotiocianatos/farmacología , Envejecimiento/efectos de los fármacos , Envejecimiento/metabolismo , Fármacos Neuroprotectores/farmacología , Astrocitos/efectos de los fármacos , Astrocitos/metabolismo , Hipotálamo/efectos de los fármacos , Hipotálamo/metabolismo , Ratas , Masculino , Células Cultivadas , Antioxidantes/farmacologíaRESUMEN
Cholesterol is crucial for the proper functioning of eukaryotic cells, especially neurons, which rely on cholesterol to maintain their complex structure and facilitate synaptic transmission. However, brain cells are isolated from peripheral cholesterol by the blood-brain barrier and mature neurons primarily uptake the cholesterol synthesized by astrocytes for proper function. This study aimed to investigate the effect of aging on cholesterol trafficking in astrocytes and its delivery to neurons. We found that aged astrocytes accumulated high levels of cholesterol in the lysosomal compartment, and this cholesterol buildup can be attributed to the simultaneous occurrence of two events: decreased levels of the ABCA1 transporter, which impairs ApoE-cholesterol export from astrocytes, and reduced expression of NPC1, which hinders cholesterol release from lysosomes. We show that these two events are accompanied by increased microR-33 in aged astrocytes, which targets ABCA1 and NPC1. In addition, we demonstrate that the microR-33 increase is triggered by oxidative stress, one of the hallmarks of aging. By coculture experiments, we show that cholesterol accumulation in astrocytes impairs the cholesterol delivery from astrocytes to neurons. Remarkably, we found that this altered transport of cholesterol could be alleviated through treatment with endocannabinoids as well as cannabidiol or CBD. Finally, according to data demonstrating that aged astrocytes develop an A1 phenotype, we found that cholesterol buildup is also observed in reactive C3+ astrocytes. Given that reduced neuronal cholesterol affects synaptic plasticity, the ability of cannabinoids to restore cholesterol transport from aged astrocytes to neurons holds significant implications in aging and inflammation.
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Transportador 1 de Casete de Unión a ATP , Astrocitos , Cannabinoides , Colesterol , Lisosomas , Neuronas , Astrocitos/metabolismo , Astrocitos/efectos de los fármacos , Animales , Colesterol/metabolismo , Neuronas/metabolismo , Neuronas/efectos de los fármacos , Lisosomas/metabolismo , Lisosomas/efectos de los fármacos , Transportador 1 de Casete de Unión a ATP/metabolismo , Cannabinoides/farmacología , Cannabinoides/metabolismo , Células Cultivadas , Proteína Niemann-Pick C1 , Ratones , Envejecimiento/metabolismo , Técnicas de Cocultivo , Ratones Endogámicos C57BLRESUMEN
Alzheimer's disease (AD) is a progressive neurodegenerative disease characterized by cognitive impairment associated with the accumulation of beta-amyloid protein (Aß). Aß activates glial cells in the brain, increasing the secretion of proinflammatory cytokines, which leads to neuroinflammation and neuronal death. Currently, there are no effective treatments that cure or stop its progression; therefore, AD is considered a global health priority. The main limitations are the low drug bioavailability and impermeability of the blood-brain barrier (BBB). Fortunately, nanomedicine has emerged as a promising field for the development of new nanosystems for the controlled and targeted delivery of drugs to the brain. Therefore, in this work, lipid-polymer hybrid nanoparticles (LPHNPs) conjugated with transferrin (Tf) to facilitate crossing the BBB and loaded with N-acetylcysteine (NAC) for its anti-inflammatory effect were synthesized, and their physicochemical characterization was carried out. Subsequently, an in vitro model involving human astrocytes derived from induced pluripotent stem cells (iPSC) from an AD-diagnosed patient was developed, which was brought to a reactive state by stimulation with lipopolysaccharides (LPSs). The cell culture was treated with either Tf-conjugated LPHNPs loaded with NAC (NAC-Tf-LPHNPs) at 0.25 mg mL-1, or free NAC at 5 mM. The results showed that NAC-Tf-LPHNPs favorably modulated the expression of proinflammatory genes such as interleukin-1ß (IL-1ß), amyloid precursor protein (APP) and glial fibrillary acidic protein (GFAP). In addition, they reduced the secretion of the proinflammatory cytokines interleukin 6 (IL-6), IL-1ß and interferon-gamma (INF-γ). Results for both cases were compared to the group of cells that did not receive any treatment. In contrast, free NAC only had this effect on the expression of IL-1ß and the secretion of the cytokines IL-6 and INF-γ. These results indicate the potential of NAC-Tf-LPHNPs for AD treatment.
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Acetilcisteína , Enfermedad de Alzheimer , Astrocitos , Células Madre Pluripotentes Inducidas , Nanopartículas , Humanos , Enfermedad de Alzheimer/tratamiento farmacológico , Enfermedad de Alzheimer/metabolismo , Nanopartículas/química , Células Madre Pluripotentes Inducidas/metabolismo , Células Madre Pluripotentes Inducidas/efectos de los fármacos , Acetilcisteína/química , Acetilcisteína/farmacología , Astrocitos/efectos de los fármacos , Astrocitos/metabolismo , Polímeros/química , Polímeros/farmacología , Lípidos/química , Biomarcadores/metabolismo , Tamaño de la Partícula , Enfermedades Neuroinflamatorias/tratamiento farmacológicoRESUMEN
Autism spectrum disorder (ASD) exhibits a gender bias, with boys more frequently affected than girls. Similarly, in mouse models induced by prenatal exposure to valproic acid (VPA), males typically display reduced sociability, while females are less affected. Although both males and females exhibit VPA effects on neuroinflammatory parameters, these effects are sex-specific. Notably, females exposed to VPA show increased microglia and astrocyte density during the juvenile period. We hypothesized that these distinct neuroinflammatory patterns contribute to the resilience of females to VPA. To investigate this hypothesis, we treated juvenile animals with intraperitoneal bacterial lipopolysaccharides (LPS), a treatment known to elicit brain neuroinflammation. We thus evaluated the impact of juvenile LPS-induced inflammation on adult sociability and neuroinflammation in female mice prenatally exposed to VPA. Our results demonstrate that VPA-LPS females exhibit social deficits in adulthood, overriding the resilience observed in VPA-saline littermates. Repetitive behavior and anxiety levels were not affected by either treatment. We also evaluated whether the effect on sociability was accompanied by heightened neuroinflammation in the cerebellum and hippocampus. Surprisingly, we observed reduced astrocyte and microglia density in the cerebellum of VPA-LPS animals. These findings shed light on the complex interactions between prenatal insults, juvenile inflammatory stimuli, and sex-specific vulnerability in ASD-related social deficits, providing insights into potential therapeutic interventions for ASD.
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Trastorno del Espectro Autista , Lipopolisacáridos , Efectos Tardíos de la Exposición Prenatal , Conducta Social , Ácido Valproico , Animales , Femenino , Efectos Tardíos de la Exposición Prenatal/inducido químicamente , Embarazo , Ratones , Ácido Valproico/efectos adversos , Masculino , Trastorno del Espectro Autista/inducido químicamente , Trastorno del Espectro Autista/etiología , Microglía/efectos de los fármacos , Microglía/metabolismo , Modelos Animales de Enfermedad , Conducta Animal/efectos de los fármacos , Astrocitos/efectos de los fármacos , Astrocitos/metabolismo , Ratones Endogámicos C57BLRESUMEN
Methylglyoxal (MG) is considered a classical biomarker of diabetes mellitus and its comorbidities. However, a role for this compound in exacerbated immune responses, such as septicemia, is being increasingly observed and requires clarification, particularly in the context of neuroinflammatory responses. Herein, we used two different approaches (in vivo and acute hippocampal slice models) to investigate MG as a biomarker of neuroinflammation and the neuroimmunometabolic shift to glycolysis in lipopolysaccharide (LPS) inflammation models. Our data reinforce the hypothesis that LPS-induced neuroinflammation stimulates the cerebral innate immune response by increasing IL-1ß, a classical pro-inflammatory cytokine, and the astrocyte reactive response, via elevating S100B secretion and GFAP levels. Acute neuroinflammation promotes an early neuroimmunometabolic shift to glycolysis by elevating glucose uptake, lactate release, PFK1, and PK activities. We observed high serum and cerebral MG levels, in association with a reduction in glyoxalase 1 detoxification activity, and a close correlation between serum and hippocampus MG levels with the systemic and neuroinflammatory responses to LPS. Findings strongly suggest a role for MG in immune responses.
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Biomarcadores , Hipocampo , Lipopolisacáridos , Enfermedades Neuroinflamatorias , Piruvaldehído , Piruvaldehído/metabolismo , Lipopolisacáridos/farmacología , Animales , Enfermedades Neuroinflamatorias/metabolismo , Enfermedades Neuroinflamatorias/inducido químicamente , Biomarcadores/metabolismo , Masculino , Hipocampo/metabolismo , Hipocampo/efectos de los fármacos , Ratas Wistar , Subunidad beta de la Proteína de Unión al Calcio S100/metabolismo , Glucólisis/efectos de los fármacos , Interleucina-1beta/metabolismo , Inflamación/metabolismo , Inflamación/inducido químicamente , Proteína Ácida Fibrilar de la Glía/metabolismo , Lactoilglutatión Liasa/metabolismo , Ratas , Astrocitos/metabolismo , Astrocitos/efectos de los fármacosRESUMEN
BACKGROUND: In Chagas disease (CD), a neglected tropical disease caused by the parasite Trypanosoma cruzi, the development of mental disorders such as anxiety, depression, and memory loss may be underpinned by social, psychological, and biological stressors. Here, we investigated biological factors underlying behavioral changes in a preclinical model of CD. METHODOLOGY/PRINCIPAL FINDINGS: In T. cruzi-infected C57BL/6 mice, a kinetic study (5 to 150 days postinfection, dpi) using standardized methods revealed a sequential onset of behavioral changes: reduced innate compulsive behavior, followed by anxiety and depressive-like behavior, ending with progressive memory impairments. Hence, T. cruzi-infected mice were treated (120 to 150 dpi) with 10 mg/Kg/day of the selective serotonin reuptake inhibitor fluoxetine (Fx), an antidepressant that favors neuroplasticity. Fx therapy reversed the innate compulsive behavior loss, anxiety, and depressive-like behavior while preventing or reversing memory deficits. Biochemical, histological, and parasitological analyses of the brain tissue showed increased levels of the neurotransmitters GABA/glutamate and lipid peroxidation products and decreased expression of brain-derived neurotrophic factor in the absence of neuroinflammation at 150 dpi. Fx therapy ameliorated the neurochemical changes and reduced parasite load in the brain tissue. Next, using the human U-87 MG astroglioma cell line, we found no direct effect of Fx on parasite load. Crucially, serotonin/5-HT (Ser/5-HT) promoted parasite uptake, an effect increased by prior stimulation with IFNγ and TNF but abrogated by Fx. Also, Fx blocked the cytokine-driven Ser/5-HT-promoted increase of nitric oxide and glutamate levels in infected cells. CONCLUSION/SIGNIFICANCE: We bring the first evidence of a sequential onset of behavioral changes in T. cruzi-infected mice. Fx therapy improves behavioral and biological changes and parasite control in the brain tissue. Moreover, in the central nervous system, cytokine-driven Ser/5-HT consumption may favor parasite persistence, disrupting neurotransmitter balance and promoting a neurotoxic environment likely contributing to behavioral and cognitive disorders.
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Astrocitos , Enfermedad de Chagas , Fluoxetina , Ratones Endogámicos C57BL , Serotonina , Trypanosoma cruzi , Animales , Fluoxetina/farmacología , Fluoxetina/uso terapéutico , Enfermedad de Chagas/tratamiento farmacológico , Enfermedad de Chagas/psicología , Trypanosoma cruzi/efectos de los fármacos , Trypanosoma cruzi/fisiología , Serotonina/metabolismo , Ratones , Astrocitos/efectos de los fármacos , Modelos Animales de Enfermedad , Encéfalo/efectos de los fármacos , Encéfalo/parasitología , Encéfalo/metabolismo , Conducta Animal/efectos de los fármacos , Masculino , Humanos , Inhibidores Selectivos de la Recaptación de Serotonina/farmacología , Inhibidores Selectivos de la Recaptación de Serotonina/uso terapéutico , Cognición/efectos de los fármacos , Depresión/tratamiento farmacológico , Carga de Parásitos , Ansiedad/tratamiento farmacológicoRESUMEN
Iron deficiency (ID) has been shown to affect central nervous system (CNS) development and induce hypomyelination. Previous work from our laboratory in a gestational ID model showed that both oligodendrocyte (OLG) and astrocyte (AST) maturation was impaired. To explore the contribution of AST iron to the myelination process, we generated an in vitro ID model by silencing divalent metal transporter 1 (DMT1) in AST (siDMT1 AST) or treating AST with Fe3+ chelator deferoxamine (DFX; DFX AST). siDMT1 AST showed no changes in proliferation but remained immature. Co-cultures of oligodendrocyte precursors cells (OPC) with siDMT1 AST and OPC cultures incubated with siDMT1 AST-conditioned media (ACM) rendered a reduction in OPC maturation. These findings correlated with a decrease in the expression of AST-secreted factors IGF-1, NRG-1, and LIF, known to promote OPC differentiation. siDMT1 AST also displayed increased mitochondrial number and reduced mitochondrial size as compared to control cells. DFX AST also remained immature and DFX AST-conditioned media also hampered OPC maturation in culture, in keeping with a decrease in the expression of AST-secreted growth factors IGF-1, NRG-1, LIF, and CNTF. DFX AST mitochondrial morphology and number showed results similar to those observed in siDMT1 AST. In sum, our results show that ID, induced through two different methods, impacts AST maturation and mitochondrial functioning, which in turn hampers OPC differentiation.
Asunto(s)
Astrocitos , Diferenciación Celular , Deficiencias de Hierro , Oligodendroglía , Astrocitos/metabolismo , Astrocitos/efectos de los fármacos , Oligodendroglía/metabolismo , Oligodendroglía/efectos de los fármacos , Animales , Diferenciación Celular/efectos de los fármacos , Diferenciación Celular/fisiología , Células Cultivadas , Proteínas de Transporte de Catión/metabolismo , Técnicas de Cocultivo , Medios de Cultivo Condicionados/farmacología , Ratas , Células Precursoras de Oligodendrocitos/efectos de los fármacos , Células Precursoras de Oligodendrocitos/metabolismo , Deferoxamina/farmacología , Proliferación Celular/efectos de los fármacos , Proliferación Celular/fisiología , Hierro/metabolismoRESUMEN
Chronic neuroinflammation has been implicated in neurodegenerative disease pathogenesis. A key feature of neuroinflammation is neuronal loss and glial activation, including microglia and astrocytes. 4R-cembranoid (4R) is a natural compound that inhibits hippocampal pro-inflammatory cytokines and increases memory function in mice. We used the lipopolysaccharide (LPS) injection model to study the effect of 4R on neuronal density and microglia and astrocyte activation. C57BL/6J wild-type mice were injected with LPS (5 mg/kg) and 2 h later received either 4R (6 mg/kg) or vehicle. Mice were sacrificed after 72 h for analysis of brain pathology. Confocal images of brain sections immunostained for microglial, astrocyte, and neuronal markers were used to quantify cellular hippocampal phenotypes and neurons. Hippocampal lysates were used to measure the expression levels of neuronal nuclear protein (NeuN), inducible nitrous oxide synthase (iNOS), arginase-1, thrombospondin-1 (THBS1), glial cell-derived neurotrophic factor (GDNF), and orosomucoid-2 (ORM2) by western blot. iNOS and arginase-1 are widely used protein markers of pro- and anti-inflammatory microglia, respectively. GDNF promotes neuronal survival, and ORM2 and THBS1 are astrocytic proteins that regulate synaptic plasticity and inhibit microglial activation. 4R administration significantly reduced neuronal loss and the number of pro-inflammatory microglia 72 h after LPS injection. It also decreased the expression of the pro-inflammatory protein iNOS while increasing arginase-1 expression, supporting its anti-inflammatory role. The protein expression of THBS1, GDNF, and ORM2 was increased by 4R. Our data show that 4R preserves the integrity of hippocampal neurons against LPS-induced neuroinflammation in mice.
Asunto(s)
Hipocampo , Lipopolisacáridos , Ratones Endogámicos C57BL , Neuroglía , Neuronas , Animales , Lipopolisacáridos/toxicidad , Hipocampo/efectos de los fármacos , Hipocampo/metabolismo , Hipocampo/patología , Ratones , Neuronas/efectos de los fármacos , Neuronas/metabolismo , Neuronas/patología , Neuroglía/efectos de los fármacos , Neuroglía/metabolismo , Neuroglía/patología , Masculino , Microglía/efectos de los fármacos , Microglía/metabolismo , Microglía/patología , Enfermedades Neuroinflamatorias/metabolismo , Enfermedades Neuroinflamatorias/patología , Enfermedades Neuroinflamatorias/tratamiento farmacológico , Fenotipo , Astrocitos/efectos de los fármacos , Astrocitos/metabolismo , Astrocitos/patologíaRESUMEN
BACKGROUND: Astrocytes Ca2+ signaling play a central role in the modulation of neuronal function. Activation of metabotropic glutamate receptors (mGluR) by glutamate released during an increase in synaptic activity triggers coordinated Ca2+ signals in astrocytes. Importantly, astrocytes express the Ca2+-dependent nitric oxide (NO)-synthetizing enzymes eNOS and nNOS, which might contribute to the Ca2+ signals by triggering Ca2+ influx or ATP release through the activation of connexin 43 (Cx43) hemichannels, pannexin-1 (Panx-1) channels or Ca2+ homeostasis modulator 1 (CALHM1) channels. Hence, we aim to evaluate the participation of NO in the astrocytic Ca2+ signaling initiated by stimulation of mGluR in primary cultures of astrocytes from rat brain cortex. RESULTS: Astrocytes were stimulated with glutamate or t-ACPD and NO-dependent changes in [Ca2+]i and ATP release were evaluated. In addition, the activity of Cx43 hemichannels, Panx-1 channels and CALHM1 channels was also analyzed. The expression of Cx43, Panx-1 and CALHM1 in astrocytes was confirmed by immunofluorescence analysis and both glutamate and t-ACPD induced NO-mediated activation of CALHM1 channels via direct S-nitrosylation, which was further confirmed by assessing CALHM1-mediated current using the two-electrode voltage clamp technique in Xenopus oocytes. Pharmacological blockade or siRNA-mediated inhibition of CALHM1 expression revealed that the opening of these channels provides a pathway for ATP release and the subsequent purinergic receptor-dependent activation of Cx43 hemichannels and Panx-1 channels, which further contributes to the astrocytic Ca2+ signaling. CONCLUSIONS: Our findings demonstrate that activation of CALHM1 channels through NO-mediated S-nitrosylation in astrocytes in vitro is critical for the generation of glutamate-initiated astrocytic Ca2+ signaling.
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Astrocitos , Señalización del Calcio , Óxido Nítrico , Animales , Ratas , Astrocitos/metabolismo , Astrocitos/efectos de los fármacos , Calcio/metabolismo , Canales de Calcio/metabolismo , Señalización del Calcio/fisiología , Señalización del Calcio/efectos de los fármacos , Células Cultivadas , Conexina 43/metabolismo , Ácido Glutámico/metabolismo , Óxido Nítrico/metabolismo , Ratas WistarRESUMEN
Accidents caused by Bothrops jararaca (Bj) snakes result in several local and systemic manifestations, with pain being a fundamental characteristic. The inflammatory process responsible for hyperalgesia induced by Bj venom (Bjv) has been studied; however, the specific roles played by the peripheral and central nervous systems in this phenomenon remain unclear. To clarify this, we induced hyperalgesia in rats using Bjv and collected tissues from dorsal root ganglia (DRGs) and spinal cord (SC) at 2 and 4 h post-induction. Samples were labeled for Iba-1 (macrophage and microglia), GFAP (satellite cells and astrocytes), EGR1 (neurons), and NK1 receptors. Additionally, we investigated the impact of minocycline, an inhibitor of microglia, and GR82334 antagonist on Bjv-induced hyperalgesia. Our findings reveal an increase in Iba1 in DRG at 2 h and EGR1 at 4 h. In the SC, markers for microglia, astrocytes, neurons, and NK1 receptors exhibited increased expression after 2 h, with EGR1 continuing to rise at 4 h. Minocycline and GR82334 inhibited venom-induced hyperalgesia, highlighting the crucial roles of microglia and NK1 receptors in this phenomenon. Our results suggest that the hyperalgesic effects of Bjv involve the participation of microglial and astrocytic cells, in addition to the activation of NK1 receptors.
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Bothrops , Venenos de Crotálidos , Ganglios Espinales , Hiperalgesia , Receptores de Neuroquinina-1 , Animales , Hiperalgesia/inducido químicamente , Hiperalgesia/metabolismo , Venenos de Crotálidos/toxicidad , Masculino , Ganglios Espinales/efectos de los fármacos , Ganglios Espinales/metabolismo , Receptores de Neuroquinina-1/metabolismo , Minociclina/farmacología , Médula Espinal/efectos de los fármacos , Médula Espinal/metabolismo , Proteína 1 de la Respuesta de Crecimiento Precoz/metabolismo , Proteína 1 de la Respuesta de Crecimiento Precoz/genética , Microglía/efectos de los fármacos , Microglía/metabolismo , Neuroglía/efectos de los fármacos , Neuroglía/metabolismo , Ratas , Proteína Ácida Fibrilar de la Glía/metabolismo , Proteínas de Unión al Calcio/metabolismo , Astrocitos/efectos de los fármacos , Astrocitos/metabolismo , Proteínas de Microfilamentos/metabolismo , Antagonistas del Receptor de Neuroquinina-1/farmacología , Ratas Sprague-DawleyRESUMEN
Growing evidence indicates a critical role of astrocytes in learning and memory. However, little is known about the role of basolateral amygdala complex (BLA-C) astrocytes in contextual fear conditioning (CFC), a paradigm relevant to understand and generate treatments for fear- and anxiety-related disorders. To get insights on the involvement of BLA-C astrocytes in fear memory, fluorocitrate (FLC), a reversible astroglial metabolic inhibitor, was applied at critical moments of the memory processing in order to target the acquisition, consolidation, retrieval and reconsolidation process of the fear memory. Adult Wistar male rats were bilaterally cannulated in BLA-C. Ten days later they were infused with different doses of FLC (0.5 or 1 nmol/0.5 µl) or saline before or after CFC and before or after retrieval. FLC impaired fear memory expression when administered before and shortly after CFC, but not one hour later. Infusion of FLC prior and after retrieval did not affect the memory. Our findings suggest that BLA-C astrocytes are critically involved in the acquisition/early consolidation of fear memory but not in the retrieval and reconsolidation. Furthermore, the extinction process was presumably not affected (considering that peri-retrieval administration could also affect this process).
Asunto(s)
Astrocitos , Complejo Nuclear Basolateral , Miedo , Memoria , Ratas Wistar , Animales , Miedo/fisiología , Miedo/efectos de los fármacos , Astrocitos/efectos de los fármacos , Astrocitos/fisiología , Masculino , Complejo Nuclear Basolateral/efectos de los fármacos , Complejo Nuclear Basolateral/fisiología , Ratas , Memoria/fisiología , Memoria/efectos de los fármacos , Citratos/farmacología , Condicionamiento Clásico/efectos de los fármacos , Condicionamiento Clásico/fisiología , Consolidación de la Memoria/fisiología , Consolidación de la Memoria/efectos de los fármacos , Amígdala del Cerebelo/efectos de los fármacos , Amígdala del Cerebelo/fisiología , Extinción Psicológica/efectos de los fármacos , Extinción Psicológica/fisiologíaRESUMEN
Wnt signaling plays an important role in adult brain function, and its dysregulation has been implicated in the loss of neuronal homeostasis. Despite the existence of many studies on the participation of the Wnt pathway in adult neurons, its regulation in astrocytes has been scarcely explored. Several reports point to the presence of Wnt ligands in astrocytes and their possible impact on neuronal plasticity or neuronal death. We aimed to analyze the effect of the neurotransmitter glutamate and the inflammatory cytokine TNFα on the mRNA and protein levels of the canonical Wnt agonist Wnt7a and the antagonist Dkk1 in cultured astrocytes. Primary astrocyte cultures from rat cerebral cortices were exposed to glutamate or TNFα. Wnt7a and Dkk1 expression was analyzed by RT-qPCR and its protein abundance and distribution was assessed by immunofluorescence. We found high basal expression and protein levels of Wnt7a and Dkk1 in unstimulated astrocytes and overproduction of Dkk1 mRNA induced by the two stimuli. These results reveal the astrocytic source of the canonical Wnt ligands Wnt7a and Dkk1, whose levels are differentially regulated by glutamate and TNFα. Astrocytes are a significant source of Wnt ligands, the production of which can be differentially regulated under excitatory or proinflammatory conditions, thereby impacting neuronal function.