RESUMEN
Microglia are highly dynamic cells that have been mainly studied under pathological conditions. The present review discusses the possible implication of microglia as modulators of neuronal electrical responses in physiological conditions and hypothesizes how these cells might modulate hypothalamic circuits in health and during obesity. Microglial cells studied under physiological conditions are highly diverse, depending on the developmental stage and brain region. The evidence also suggests that neuronal electrical activity modulates microglial motility to control neuronal excitability. Additionally, we show that the expression of genes associated with neuron-microglia interaction is down-regulated in obese mice compared to control-fed mice, suggesting an alteration in the contact-dependent mechanisms that sustain hypothalamic arcuate-median eminence neuronal function. We also discuss the possible implication of microglial-derived signals for the excitability of hypothalamic neurons during homeostasis and obesity. This review emphasizes the importance of studying the physiological interplay between microglia and neurons to maintain proper neuronal circuit function. It aims to elucidate how disruptions in the normal activities of microglia can adversely affect neuronal health.
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Núcleo Arqueado del Hipotálamo , Homeostasis , Microglía , Neuronas , Microglía/metabolismo , Animales , Núcleo Arqueado del Hipotálamo/metabolismo , Humanos , Neuronas/metabolismo , Neuronas/fisiología , Obesidad/metabolismo , Obesidad/fisiopatología , RatonesRESUMEN
Microglial cells are the most receptive cells in the central nervous system (CNS), expressing several classes of receptors reflecting their immune heritage and newly acquired neural specialisation. Microglia possess, depending on the particular context, receptors to neurotransmitters and neuromodulators as well as immunocompetent receptors. This rich complement allows microglial cells to monitor the functional status of the nervous system, contribute actively to the regulation of neural activity and plasticity and homeostasis, and guard against pathogens as well as other challenges to the CNS's integrity and function.
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Microglía , Microglía/metabolismo , Humanos , Animales , Sistema Nervioso Central/metabolismo , Plasticidad Neuronal/fisiologíaRESUMEN
Microglia are specialized immune cells that reside in the central nervous system (CNS) and play a crucial role in maintaining the homeostasis of the brain microenvironment. While traditionally regarded as a part of the innate immune system, recent research has highlighted their role in adaptive immunity. The CNS is no longer considered an immune-privileged organ, and increasing evidence suggests bidirectional communication between the immune system and the CNS. Microglia are sensitive to systemic immune signals and can respond to systemic inflammation by producing various inflammatory cytokines and chemokines. This response is mediated by activating pattern recognition receptors (PRRs), which recognize pathogen- and danger-associated molecular patterns in the systemic circulation. The microglial response to systemic inflammation has been implicated in several neurological conditions, including depression, anxiety, and cognitive impairment. Understanding the complex interplay between microglia and systemic immunity is crucial for developing therapeutic interventions to modulate immune responses in the CNS.
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Inmunidad Innata , Microglía , Microglía/inmunología , Microglía/metabolismo , Humanos , Animales , Inmunidad Innata/inmunología , Inflamación/inmunología , Sistema Nervioso Central/inmunología , Sistema Nervioso Central/metabolismo , Citocinas/inmunología , Citocinas/metabolismo , Receptores de Reconocimiento de Patrones/inmunología , Receptores de Reconocimiento de Patrones/metabolismo , Inmunidad Adaptativa/inmunología , Encéfalo/inmunologíaRESUMEN
Aging is the greatest risk factor for neurodegenerative diseases. Microglia are the resident immune cells in the central nervous system (CNS), playing key roles in its normal functioning, and as mediators for age-dependent changes of the CNS, condition at which they generate a hostile environment for neurons. Transforming Growth Factor ß1 (TGFß1) is a regulatory cytokine involved in immuneregulation and neuroprotection, affecting glial cell inflammatory activation, neuronal survival, and function. TGFß1 signaling undergoes age-dependent changes affecting the regulation of microglial cells and can contribute to the pathophysiology of neurodegenerative diseases. This chapter focuses on assessing the role of age-related changes on the regulation of microglial cells and their impact on neuroinflammation and neuronal function, for understanding age-dependent changes of the nervous system.
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Envejecimiento , Microglía , Enfermedades Neuroinflamatorias , Microglía/metabolismo , Humanos , Envejecimiento/metabolismo , Envejecimiento/fisiología , Animales , Enfermedades Neuroinflamatorias/inmunología , Enfermedades Neuroinflamatorias/metabolismo , Enfermedades Neurodegenerativas/metabolismo , Factor de Crecimiento Transformador beta1/metabolismo , Sistema Nervioso Central/metabolismo , Neuronas/metabolismo , Transducción de SeñalRESUMEN
Resident macrophages are tissue-specific innate immune cells acting as sentinels, constantly patrolling their assigned tissue to maintain homeostasis, and quickly responding to pathogenic invaders or molecular danger signals molecules when necessary. Adenosine triphosphate (ATP), when released to the extracellular medium, acts as a danger signal through specific purinergic receptors. Interaction of ATP with the purinergic receptor P2X7 activates macrophages and microglial cells in different pathological conditions, triggering inflammation. The highly expressed P2X7 receptor in these cells induces cell membrane permeabilization, inflammasome activation, cell death, and the production of inflammatory mediators, including cytokines and nitrogen and oxygen-reactive species. This review explores the techniques to evaluate the functional and molecular aspects of the P2X7 receptor, particularly in macrophages and microglial cells. Polymerase chain reaction (PCR), Western blotting, and immunocytochemistry or immunohistochemistry are essential for assessing gene and protein expression in these cell types. Evaluation of P2X7 receptor function involves the use of ATP and selective agonists and antagonists and diverse techniques, including electrophysiology, intracellular calcium measurements, ethidium bromide uptake, and propidium iodide cell viability assays. These techniques are crucial for studying the role of P2X7 receptors in immune responses, neuroinflammation, and various pathological conditions. Therefore, a comprehensive understanding of the functional and molecular aspects of the P2X7 receptor in macrophages and microglia is vital for unraveling its involvement in immune modulation and its potential as a therapeutic target. The methodologies presented and discussed herein offer valuable tools for researchers investigating the complexities of P2X7 receptor signaling in innate immune cells in health and disease.
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Adenosina Trifosfato , Macrófagos , Microglía , Receptores Purinérgicos P2X7 , Receptores Purinérgicos P2X7/metabolismo , Receptores Purinérgicos P2X7/inmunología , Microglía/metabolismo , Microglía/inmunología , Humanos , Adenosina Trifosfato/metabolismo , Animales , Macrófagos/inmunología , Macrófagos/metabolismo , Inmunohistoquímica , Transducción de SeñalRESUMEN
Neurodegenerative diseases involve neuroinflammation and a loss of neurons, leading to disability and death. Hence, the research into new therapies has been focused on the modulation of the inflammatory response mainly by microglia/macrophages. The extracts and metabolites of marine sponges have been presented as anti-inflammatory. This study evaluated the toxicity of an extract and purified compound from the Brazilian marine sponge Aplysina fulva as well as its neuroprotection against inflammatory damage associated with the modulation of microglia response. PC12 neuronal cells and neonatal rat microglia were treated with the methanolic extract of A. fulva (AF-MeOH, 0.1-200 µg/mL) or with its purified dimethyl ketal of 3,5-dibromoverongiaquinol (AF-H1, 0.1-100 µM). Cytotoxicity was determined by MTT tetrazolium, Trypan blue, and propidium iodide; microglia were also treated with the conditioned medium (CM) from PC12 cells in different conditions. The microglia phenotype was determined by the expression of Iba-1 and CD68. AF-MeOH and AF-H1 were not toxic to PC12 or the microglia. Inflammatory damage with Escherichia coli lipopolysaccharide (LPS, 5 µg/mL) was not observed in the PC12 cells treated with AF-MeOH (1-10 µg/mL) or AF-H1 (1-10 µM). Microglia subjected to the CM from PC12 cells treated with LPS and AF-MeOH or AF-H1 showed the control phenotype-like (multipolar, low-CD68), highlighting the anti-neuroinflammatory and neuroprotective effect of components of this marine sponge.
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Microglía , Fármacos Neuroprotectores , Poríferos , Animales , Microglía/efectos de los fármacos , Ratas , Poríferos/química , Fármacos Neuroprotectores/farmacología , Fármacos Neuroprotectores/química , Células PC12 , Brasil , Antiinflamatorios/farmacología , Antiinflamatorios/química , Antiinflamatorios/aislamiento & purificación , Hidrocarburos Bromados/farmacología , Inflamación/tratamiento farmacológicoRESUMEN
Seven new abietane diterpenoids, comprising medusanthol A-G (1-3, 5, 7-9) and two previously identified analogs (4 and 6), were isolated from the hexane extract of the aerial parts of Medusantha martiusii. The structures of the compounds were elucidated by HRESIMS, 1D/2D NMR spectroscopic data, IR spectroscopy, NMR calculations with DP4+ probability analysis, and ECD calculations. The anti-neuroinflammatory potential of compounds 1-7 was evaluated by determining their ability to inhibit the production of nitric oxide (NO) and the proinflammatory cytokine TNF-α in BV2 microglia stimulated with LPS and IFN-γ. Compounds 1-4 and 7 exhibited decreased NO levels at a concentration of 12.5 µM. Compound 1 demonstrated strong activity with an IC50 of 3.12 µM, and compound 2 had an IC50 of 15.53 µM; both compounds effectively reduced NO levels compared to the positive control quercetin (IC50 11.8 µM). Additionally, both compounds significantly decreased TNF-α levels, indicating their potential as promising anti-neuroinflammatory agents.
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Abietanos , Antiinflamatorios , Microglía , Óxido Nítrico , Abietanos/farmacología , Abietanos/química , Abietanos/aislamiento & purificación , Antiinflamatorios/farmacología , Antiinflamatorios/química , Animales , Óxido Nítrico/metabolismo , Ratones , Microglía/efectos de los fármacos , Microglía/metabolismo , Factor de Necrosis Tumoral alfa/metabolismo , Extractos Vegetales/farmacología , Extractos Vegetales/química , Línea Celular , Estructura Molecular , Lipopolisacáridos , Componentes Aéreos de las Plantas/químicaRESUMEN
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
Recent evidence has supported a pathogenic role for neuroinflammation in Parkinson's disease (PD). Inflammatory response has been associated with symptoms and subtypes of PD. However, it is unclear whether immune changes are involved in the initial pathogenesis of PD, leading to the non-motor symptoms (NMS) observed in its prodromal stage. The current study aimed to characterize the behavioral and cognitive changes in a toxin-induced model of prodromal PD-like syndrome. We also sought to investigate the role of neuroinflammation in prodromal PD-related NMS. Male mice were subjected to bilateral intranasal infusion with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) or saline (control group), followed by comprehensive behavioral, pathological and neurochemical analysis. Intranasal MPTP infusion was able to cause the loss of dopaminergic neurons in the substantia nigra (SN). In parallel, it induced impairment in olfactory discrimination and social memory consolidation, compulsive and anxiety-like behaviors, but did not influence motor performance. Iba-1 and GFAP expressions were increased in the SN, suggesting an activated state of microglia and astrocytes. Consistent with this, MPTP mice had increased levels of IL-10 and IL-17A, and decreased levels of BDNF and TrkA mRNA in the SN. The striatum showed increased IL-17A, BDNF, and NFG levels compared to control mice. In conclusion, neuroinflammation may play an important role in the early stage of experimental PD-like syndrome, leading to cognitive and behavioral changes. Our results also indicate that intranasal administration of MPTP may represent a valuable mouse model for prodromal PD.
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Modelos Animales de Enfermedad , Ratones Endogámicos C57BL , Síntomas Prodrómicos , Sustancia Negra , Animales , Masculino , Sustancia Negra/metabolismo , Sustancia Negra/patología , Sustancia Negra/efectos de los fármacos , Neuronas Dopaminérgicas/patología , Neuronas Dopaminérgicas/metabolismo , Neuronas Dopaminérgicas/efectos de los fármacos , Enfermedades Neuroinflamatorias/patología , Cuerpo Estriado/metabolismo , Cuerpo Estriado/efectos de los fármacos , Cuerpo Estriado/patología , Ratones , Microglía/metabolismo , Microglía/patología , Inflamación/inducido químicamente , Inflamación/metabolismo , Inflamación/patología , Factor Neurotrófico Derivado del Encéfalo/metabolismo , Ansiedad/etiología , 1-Metil-4-fenil-1,2,3,6-Tetrahidropiridina/farmacologíaRESUMEN
BACKGROUND: The activated microglia have been reported as pillar factors in neuropathic pain (NP) pathology, but the molecules driving pain-inducible microglial activation require further exploration. In this study, we investigated the effect of dorsal root ganglion (DRG)-derived exosomes (Exo) on microglial activation and the related mechanism. METHODS: A mouse model of NP was generated by spinal nerve ligation (SNL), and DRG-derived Exo were extracted. The effects of DRG-Exo on NP and microglial activation in SNL mice were evaluated using behavioral tests, HE staining, immunofluorescence, and western blot. Next, the differentially enriched microRNAs (miRNAs) in DRG-Exo-treated microglia were analyzed using microarrays. RT-qPCR, RNA pull-down, dual-luciferase reporter assay, and immunofluorescence were conducted to verify the binding relation between miR-16-5p and HECTD1. Finally, the effects of ubiquitination modification of HSP90 by HECTD1 on NP progression and microglial activation were investigated by Co-IP, western blot, immunofluorescence assays, and rescue experiments. RESULTS: DRG-Exo aggravated NP resulting from SNL in mice, promoted the activation of microglia in DRG, and increased neuroinflammation. miR-16-5p knockdown in DRG-Exo alleviated the stimulating effects of DRG-Exo on NP and microglial activation. DRG-Exo regulated the ubiquitination of HSP90 through the interaction between miR-16-5p and HECTD1. Ubiquitination alteration of HSP90 was involved in microglial activation during NP. CONCLUSIONS: miR-16-5p shuttled by DRG-Exo regulated the ubiquitination of HSP90 by interacting with HECTD1, thereby contributing to the microglial activation in NP.
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Exosomas , Ganglios Espinales , Proteínas HSP90 de Choque Térmico , MicroARNs , Microglía , Neuralgia , Animales , Masculino , Ratones , Modelos Animales de Enfermedad , Exosomas/metabolismo , Ganglios Espinales/metabolismo , Proteínas HSP90 de Choque Térmico/metabolismo , Ratones Endogámicos C57BL , Microglía/metabolismo , MicroARNs/metabolismo , MicroARNs/genética , Neuralgia/metabolismo , Neuralgia/genética , Ubiquitina-Proteína Ligasas/metabolismo , Ubiquitina-Proteína Ligasas/genéticaRESUMEN
Microglial cells, the immune cells of the central nervous system, are key elements regulating brain development and brain health. These cells are fully responsive to stressors, microenvironmental alterations and are actively involved in the construction of neural circuits in children and the ability to undergo full experience-dependent plasticity in adults. Since neuroinflammation is a known key element in the pathogenesis of COVID-19, one might expect the dysregulation of microglial function to severely impact both functional and structural plasticity, leading to the cognitive sequelae that appear in the pathogenesis of Long COVID. Therefore, understanding this complex scenario is mandatory for establishing the possible molecular mechanisms related to these symptoms. In the present review, we will discuss Long COVID and its association with reduced levels of BDNF, altered crosstalk between circulating immune cells and microglia, increased levels of inflammasomes, cytokines and chemokines, as well as the alterations in signaling pathways that impact neural synaptic remodeling and plasticity, such as fractalkines, the complement system, the expression of SIRPα and CD47 molecules and altered matrix remodeling. Together, these complex mechanisms may help us understand consequences of Long COVID for brain development and its association with altered brain plasticity, impacting learning disabilities, neurodevelopmental disorders, as well as cognitive decline in adults.
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COVID-19 , Microglía , Adulto , Niño , Humanos , Síndrome Post Agudo de COVID-19 , COVID-19/complicaciones , Plasticidad Neuronal , Encéfalo , Progresión de la Enfermedad , CogniciónRESUMEN
Amyotrophic lateral sclerosis (ALS) is a fatal motoneuron degenerative disease that is associated with demyelination. The Wobbler (WR) mouse exhibits motoneuron degeneration, gliosis and myelin deterioration in the cervical spinal cord. Since male WRs display low testosterone (T) levels in the nervous system, we investigated if T modified myelin-relative parameters in WRs in the absence or presence of the aromatase inhibitor, anastrozole (A). We studied myelin by using luxol-fast-blue (LFB) staining, semithin sections, electron microscopy and myelin protein expression, density of IBA1+ microglia and mRNA expression of inflammatory factors, and the glutamatergic parameters glutamine synthetase (GS) and the transporter GLT1. Controls and WR + T showed higher LFB, MBP and PLP staining, lower g-ratios and compact myelin than WRs and WR + T + A, and groups showing the rupture of myelin lamellae. WRs showed increased IBA1+ cells and mRNA for CD11b and inflammatory factors (IL-18, TLR4, TNFαR1 and P2Y12R) vs. controls or WR + T. IBA1+ cells, and CD11b were not reduced in WR + T + A, but inflammatory factors' mRNA remained low. A reduction of GS+ cells and GLT-1 immunoreactivity was observed in WRs and WR + T + A vs. controls and WR + T. Clinically, WR + T but not WR + T + A showed enhanced muscle mass, grip strength and reduced paw abnormalities. Therefore, T effects involve myelin protection, a finding of potential clinical translation.
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Esclerosis Amiotrófica Lateral , Modelos Animales de Enfermedad , Vaina de Mielina , Testosterona , Animales , Ratones , Vaina de Mielina/metabolismo , Vaina de Mielina/efectos de los fármacos , Esclerosis Amiotrófica Lateral/tratamiento farmacológico , Esclerosis Amiotrófica Lateral/metabolismo , Esclerosis Amiotrófica Lateral/patología , Masculino , Testosterona/farmacología , Médula Espinal/metabolismo , Médula Espinal/efectos de los fármacos , Médula Espinal/patología , Transportador 2 de Aminoácidos Excitadores/metabolismo , Transportador 2 de Aminoácidos Excitadores/genética , Microglía/efectos de los fármacos , Microglía/metabolismo , Microglía/patologíaRESUMEN
Chronic ethanol exposure often triggers neuroinflammation in the brain's reward system, potentially promoting the drive for ethanol consumption. A main marker of neuroinflammation is the microglia-derived monocyte chemoattractant protein 1 (MCP1) in animal models of alcohol use disorder in which ethanol is forcefully given. However, there are conflicting findings on whether MCP1 is elevated when ethanol is taken voluntarily, which challenges its key role in promoting motivation for ethanol consumption. Here, we studied MCP1 mRNA levels in areas implicated in consumption motivation-specifically, the prefrontal cortex, hippocampus, and striatum-as well as in the cerebellum, a brain area highly sensitive to ethanol, of C57BL/6 mice subjected to intermittent and voluntary ethanol consumption for two months. We found a significant increase in MCP1 mRNA levels in the cerebellum of mice that consumed ethanol compared to controls, whereas no significant changes were observed in the prefrontal cortex, hippocampus, or striatum or in microglia isolated from the hippocampus and striatum. To further characterize cerebellar neuroinflammation, we measured the expression changes in other proinflammatory markers and chemokines, revealing a significant increase in the proinflammatory microRNA miR-155. Notably, other classical proinflammatory markers, such as TNFα, IL6, and IL-1ß, remained unaltered, suggesting mild neuroinflammation. These results suggest that the onset of neuroinflammation in motivation-related areas is not required for high voluntary consumption in C57BL/6 mice. In addition, cerebellar susceptibility to neuroinflammation may be a trigger to the cerebellar degeneration that occurs after chronic ethanol consumption in humans.
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Consumo de Bebidas Alcohólicas , Cerebelo , Quimiocina CCL2 , Cuerpo Estriado , Etanol , Hipocampo , Ratones Endogámicos C57BL , Corteza Prefrontal , Animales , Corteza Prefrontal/metabolismo , Corteza Prefrontal/efectos de los fármacos , Corteza Prefrontal/patología , Ratones , Hipocampo/metabolismo , Hipocampo/efectos de los fármacos , Hipocampo/patología , Cerebelo/metabolismo , Cerebelo/efectos de los fármacos , Cerebelo/patología , Masculino , Cuerpo Estriado/metabolismo , Cuerpo Estriado/patología , Cuerpo Estriado/efectos de los fármacos , Etanol/efectos adversos , Consumo de Bebidas Alcohólicas/efectos adversos , Quimiocina CCL2/metabolismo , Quimiocina CCL2/genética , Enfermedades Neuroinflamatorias/metabolismo , Enfermedades Neuroinflamatorias/etiología , Enfermedades Neuroinflamatorias/patología , Microglía/metabolismo , Microglía/efectos de los fármacos , Microglía/patología , Inflamación/metabolismo , Inflamación/patología , Inflamación/inducido químicamenteRESUMEN
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.
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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
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
BACKGROUND: Patients with liver cirrhosis may show minimal hepatic encephalopathy (MHE) with mild cognitive impairment and motor incoordination. Rats with chronic hyperammonemia reproduce these alterations. Motor incoordination in hyperammonemic rats is due to increased GABAergic neurotransmission in cerebellum, induced by neuroinflammation, which enhances TNFα-TNFR1-S1PR2-CCL2-BDNF-TrkB pathway activation. The initial events by which hyperammonemia triggers activation of this pathway remain unclear. MHE in cirrhotic patients is triggered by a shift in inflammation with increased IL-17. The aims of this work were: (1) assess if hyperammonemia increases IL-17 content and membrane expression of its receptor in cerebellum of hyperammonemic rats; (2) identify the cell types in which IL-17 receptor is expressed and IL-17 increases in hyperammonemia; (3) assess if blocking IL-17 signaling with anti-IL-17 ex-vivo reverses activation of glia and of the TNFα-TNFR1-S1PR2-CCL2-BDNF-TrkB pathway. RESULTS: IL-17 levels and membrane expression of the IL-17 receptor are increased in cerebellum of rats with hyperammonemia and MHE, leading to increased activation of IL-17 receptor in microglia, which triggers activation of STAT3 and NF-kB, increasing IL-17 and TNFα levels, respectively. TNFα released from microglia activates TNFR1 in Purkinje neurons, leading to activation of NF-kB and increased IL-17 and TNFα also in these cells. Enhanced TNFR1 activation also enhances activation of the TNFR1-S1PR2-CCL2-BDNF-TrkB pathway which mediates microglia and astrocytes activation. CONCLUSIONS: All these steps are triggered by enhanced activation of IL-17 receptor in microglia and are prevented by ex-vivo treatment with anti-IL-17. IL-17 and IL-17 receptor in microglia would be therapeutic targets to treat neurological impairment in patients with MHE.
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Cerebelo , Hiperamonemia , Microglía , Ratas Wistar , Receptores de Interleucina-17 , Animales , Hiperamonemia/metabolismo , Microglía/metabolismo , Cerebelo/metabolismo , Masculino , Ratas , Receptores de Interleucina-17/metabolismo , Enfermedades Neuroinflamatorias/metabolismo , Interleucina-17/metabolismo , Encefalopatía Hepática/metabolismo , Transducción de Señal , Modelos Animales de EnfermedadRESUMEN
MicroRNAs (miRs) act as important post-transcriptional regulators of gene expression in glial cells and have been shown to be involved in the pathogenesis of neurodegenerative diseases, including Alzheimer's disease (AD). Here, we investigated the effects of agathisflavone, a biflavonoid purified from the leaves of Cenostigma pyramidale (Tul.), on modulating the expression of miRs and inflammatory mediators in activated microglia. C20 human microglia were exposed to oligomers of the ß-amyloid peptide (Aß, 500 nM) for 4 h or to lipopolysaccharide (LPS, 1 µg/mL) for 24 h and then treated or not with agathisflavone (1 µM) for 24 h. We observed that ß-amyloid and LPS activated microglia to an inflammatory state, with increased expression of miR-146a, miR-155, IL1-ß, IL-6, and NOS2. Treatment with agathisflavone resulted in a significant reduction in miR146a and miR-155 induced by LPS or Aß, as well as inflammatory cytokines IL1-ß, IL-6, and NOS2. In cells stimulated with Aß, there was an increase in p-STAT3 expression that was reduced by agathisflavone treatment. These data identify a role for miRs in the anti-inflammatory effect of agathisflavone on microglia in models of neuroinflammation and AD.
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Enfermedad de Alzheimer , Biflavonoides , MicroARNs , Humanos , Biflavonoides/farmacología , Microglía/metabolismo , Interleucina-6/metabolismo , Lipopolisacáridos/farmacología , Enfermedad de Alzheimer/metabolismo , Péptidos beta-Amiloides/metabolismo , Citocinas/metabolismo , MicroARNs/genética , Factor de Transcripción STAT3/metabolismoRESUMEN
Lactate has received attention as a potential therapeutic intervention for brain diseases, particularly those including energy deficit, exacerbated inflammation, and disrupted redox status, such as cerebral ischemia. However, lactate roles in metabolic or signaling pathways in neural cells remain elusive in the hypoxic and ischemic contexts. Here, we tested the effects of lactate on the survival of a microglial (BV-2) and a neuronal (SH-SY5Y) cell lines during oxygen and glucose deprivation (OGD) or OGD followed by reoxygenation (OGD/R). Lactate signaling was studied by using 3,5-DHBA, an exogenous agonist of lactate receptor GPR81. Inhibition of lactate dehydrogenase (LDH) or monocarboxylate transporters (MCT), using oxamate or 4-CIN, respectively, was performed to evaluate the impact of lactate metabolization and transport on cell viability. The OGD lasted 6 h and the reoxygenation lasted 24 h following OGD (OGD/R). Cell viability, extracellular lactate concentrations, microglial intracellular pH and TNF-É release, and neurite elongation were evaluated. Lactate or 3,5-DHBA treatment during OGD increased microglial survival during reoxygenation. Inhibition of lactate metabolism and transport impaired microglial and neuronal viability. OGD led to intracellular acidification in BV-2 cells, and reoxygenation increased the release of TNF-É, which was reverted by lactate and 3,5-DHBA treatment. Our results suggest that lactate plays a dual role in OGD, acting as a metabolic and a signaling molecule in BV-2 and SH-SY5Y cells. Lactate metabolism and transport are vital for cell survival during OGD. Moreover, lactate treatment and GPR81 activation during OGD promote long-term adaptations that potentially protect cells against secondary cell death during reoxygenation.
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Supervivencia Celular , Glucosa , Ácido Láctico , Microglía , Neuronas , Oxígeno , Microglía/metabolismo , Microglía/efectos de los fármacos , Glucosa/metabolismo , Glucosa/deficiencia , Humanos , Neuronas/metabolismo , Neuronas/efectos de los fármacos , Oxígeno/metabolismo , Ácido Láctico/metabolismo , Supervivencia Celular/efectos de los fármacos , Supervivencia Celular/fisiología , Animales , Ratones , Fármacos Neuroprotectores/farmacología , Hipoxia de la Célula/fisiología , Hipoxia de la Célula/efectos de los fármacos , Factor de Necrosis Tumoral alfa/metabolismo , Receptores Acoplados a Proteínas G/metabolismo , Línea Celular Tumoral , Línea Celular , Transportadores de Ácidos Monocarboxílicos/metabolismoRESUMEN
Introduction: Chemotherapy-induced neuropathic pain (CINP) is one of the main adverse effects of chemotherapy treatment. At the spinal level, CINP modulation involves glial cells that upregulate Toll-like receptor 4 (TLR4) and signaling pathways, which can be activated by pro-inflammatory mediators as the high mobility group box-1 (HMGB1). Objective: To evaluate the spinal role of HMGB1 in the paclitaxel-induced neuropathic pain via receptor for advanced glycation end products (RAGE) and TLR4 activation expressed in glial cells. Methods: Male C57BL/6 Wild type and TLR4 deficient mice were used in the paclitaxel-induced neuropathic pain model. The nociceptive threshold was measured using the von Frey filament test. In addition, recombinant HMGB1 was intrathecally (i.t.) injected to confirm its nociceptive potential. To evaluate the spinal participation of RAGE, TLR4, NF-kB, microglia, astrocytes, and MAPK p38 in HMGB1-mediated nociceptive effect during neuropathic pain and recombinant HMGB1-induced nociception, the drugs FPS-ZM1, LPS-RS, PDTC, minocycline, fluorocitrate, and SML0543 were respectively administrated by i.t. rout. Microglia, astrocytes, glial cells, RAGE, and TLR4 protein expression were analyzed by Western blot. ELISA immunoassay was also used to assess HMGB1, IL-1ß, and TNF-α spinal levels. Results: The pharmacological experiments demonstrated that spinal RAGE, TLR4, microglia, astrocytes, as well as MAPK p38 and NF-kB signaling are involved with HMGB1-induced nociception and paclitaxel-induced neuropathic pain. Furthermore, HMGB1 spinal levels were increased during the early stages of neuropathic pain and associated with RAGE, TLR4 and microglial activation. RAGE and TLR4 blockade decreased spinal levels of pro-inflammatory cytokines during neuropathic pain. Conclusion: Taken together, our findings indicate that HMGB1 may be released during the early stages of paclitaxel-induced neuropathic pain. This molecule activates RAGE and TLR4 receptors in spinal microglia, upregulating pro-inflammatory cytokines that may contribute to neuropathic pain.
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Proteína HMGB1 , Neuralgia , Animales , Masculino , Ratones , Citocinas/metabolismo , Proteína HMGB1/metabolismo , Hiperalgesia/metabolismo , Ratones Endogámicos C57BL , Microglía/metabolismo , Neuralgia/inducido químicamente , Neuralgia/metabolismo , FN-kappa B , Paclitaxel/toxicidad , Receptor para Productos Finales de Glicación Avanzada/metabolismo , Receptor Toll-Like 4/metabolismoRESUMEN
Glioblastoma (GBM) stands as the most aggressive and lethal among the main types of primary brain tumors. It exhibits malignant growth, infiltrating the brain tissue, and displaying resistance toward treatment. GBM is a complex disease characterized by high degrees of heterogeneity. During tumour growth, microglia and astrocytes, among other cells, infiltrate the tumour microenvironment and contribute extensively to gliomagenesis. Tumour-associated macrophages (TAMs), either of peripheral origin or representing brain-intrinsic microglia, are the most numerous nonneoplastic populations in the tumour microenvironment in GBM. The complex heterogeneous nature of GBM cells is facilitated by the local inflammatory tumour microenvironment, which mostly induces tumour aggressiveness and drug resistance. The immunosuppressive tumour microenvironment of GBM provides multiple pathways for tumour immune evasion, contributing to tumour progression. Additionally, TAMs and astrocytes can contribute to tumour progression through the release of cytokines and activation of signalling pathways. In this review, we summarize the role of the microenvironment in GBM progression, focusing on neuroinflammation. These recent advancements in research of the microenvironment hold the potential to offer a promising approach to the treatment of GBM in the coming times.