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1.
Nat Commun ; 11(1): 4966, 2020 10 02.
Artigo em Inglês | MEDLINE | ID: mdl-33009404

RESUMO

Temporal lobe epilepsy (TLE) is the most common type of drug-resistant epilepsy in adults, with an unknown etiology. A hallmark of TLE is the characteristic loss of layer 3 neurons in the medial entorhinal area (MEA) that underlies seizure development. One approach to intervention is preventing loss of these neurons through better understanding of underlying pathophysiological mechanisms. Here, we show that both neurons and glia together give rise to the pathology that is mitigated by the amino acid D-serine whose levels are potentially diminished under epileptic conditions. Focal administration of D-serine to the MEA attenuates neuronal loss in this region thereby preventing epileptogenesis in an animal model of TLE. Additionally, treatment with D-serine reduces astrocyte counts in the MEA, alters their reactive status, and attenuates proliferation and/or infiltration of microglia to the region thereby curtailing the deleterious consequences of neuroinflammation. Given the paucity of compounds that reduce hyperexcitability and neuron loss, have anti-inflammatory properties, and are well tolerated by the brain, D-serine, an endogenous amino acid, offers new hope as a therapeutic agent for refractory TLE.


Assuntos
Epilepsia do Lobo Temporal/tratamento farmacológico , Epilepsia do Lobo Temporal/patologia , Serina/uso terapêutico , Animais , Astrócitos/efeitos dos fármacos , Astrócitos/patologia , Comportamento Animal , Encéfalo/patologia , Córtex Entorrinal/efeitos dos fármacos , Córtex Entorrinal/patologia , Gliose/patologia , Inflamação/patologia , Microglia/efeitos dos fármacos , Microglia/patologia , Neurônios/efeitos dos fármacos , Neurônios/patologia , Ratos Sprague-Dawley , Serina/administração & dosagem , Serina/farmacologia
2.
Nat Commun ; 11(1): 5073, 2020 10 08.
Artigo em Inglês | MEDLINE | ID: mdl-33033238

RESUMO

Brain cells continuously produce and release protons into the extracellular space, with the rate of acid production corresponding to the levels of neuronal activity and metabolism. Efficient buffering and removal of excess H+ is essential for brain function, not least because all the electrogenic and biochemical machinery of synaptic transmission is highly sensitive to changes in pH. Here, we describe an astroglial mechanism that contributes to the protection of the brain milieu from acidification. In vivo and in vitro experiments conducted in rodent models show that at least one third of all astrocytes release bicarbonate to buffer extracellular H+ loads associated with increases in neuronal activity. The underlying signalling mechanism involves activity-dependent release of ATP triggering bicarbonate secretion by astrocytes via activation of metabotropic P2Y1 receptors, recruitment of phospholipase C, release of Ca2+ from the internal stores, and facilitated outward HCO3- transport by the electrogenic sodium bicarbonate cotransporter 1, NBCe1. These results show that astrocytes maintain local brain extracellular pH homeostasis via a neuronal activity-dependent release of bicarbonate. The data provide evidence of another important metabolic housekeeping function of these glial cells.


Assuntos
Astrócitos/metabolismo , Bicarbonatos/metabolismo , Encéfalo/metabolismo , Espaço Extracelular/metabolismo , Acetazolamida/farmacologia , Trifosfato de Adenosina/metabolismo , Animais , Astrócitos/efeitos dos fármacos , Anidrases Carbônicas/metabolismo , Células Cultivadas , Estimulação Elétrica , Fluorescência , Hipocampo/metabolismo , Concentração de Íons de Hidrogênio , Camundongos Endogâmicos C57BL , Modelos Biológicos , Neurônios/efeitos dos fármacos , Neurônios/metabolismo , Antagonistas Purinérgicos/farmacologia , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Ratos Sprague-Dawley , Receptores Purinérgicos/metabolismo , Transdução de Sinais , Simportadores de Sódio-Bicarbonato/metabolismo
3.
Nat Commun ; 11(1): 4458, 2020 09 07.
Artigo em Inglês | MEDLINE | ID: mdl-32895383

RESUMO

In rodent models of type 2 diabetes (T2D), sustained remission of hyperglycemia can be induced by a single intracerebroventricular (icv) injection of fibroblast growth factor 1 (FGF1), and the mediobasal hypothalamus (MBH) was recently implicated as the brain area responsible for this effect. To better understand the cellular response to FGF1 in the MBH, we sequenced >79,000 single-cell transcriptomes from the hypothalamus of diabetic Lepob/ob mice obtained on Days 1 and 5 after icv injection of either FGF1 or vehicle. A wide range of transcriptional responses to FGF1 was observed across diverse hypothalamic cell types, with glial cell types responding much more robustly than neurons at both time points. Tanycytes and ependymal cells were the most FGF1-responsive cell type at Day 1, but astrocytes and oligodendrocyte lineage cells subsequently became more responsive. Based on histochemical and ultrastructural evidence of enhanced cell-cell interactions between astrocytes and Agrp neurons (key components of the melanocortin system), we performed a series of studies showing that intact melanocortin signaling is required for the sustained antidiabetic action of FGF1. These data collectively suggest that hypothalamic glial cells are leading targets for the effects of FGF1 and that sustained diabetes remission is dependent on intact melanocortin signaling.


Assuntos
Diabetes Mellitus Experimental/dietoterapia , Diabetes Mellitus Tipo 2/tratamento farmacológico , Fator 1 de Crescimento de Fibroblastos/administração & dosagem , Hipoglicemiantes/administração & dosagem , Hipotálamo/efeitos dos fármacos , Proteínas Recombinantes/administração & dosagem , Proteína Relacionada com Agouti/metabolismo , Animais , Astrócitos/efeitos dos fármacos , Astrócitos/metabolismo , Glicemia/análise , Comunicação Celular , Núcleo Celular/efeitos dos fármacos , Núcleo Celular/metabolismo , Diabetes Mellitus Experimental/sangue , Diabetes Mellitus Experimental/etiologia , Diabetes Mellitus Experimental/patologia , Diabetes Mellitus Tipo 2/sangue , Diabetes Mellitus Tipo 2/etiologia , Diabetes Mellitus Tipo 2/patologia , Dieta Hiperlipídica/efeitos adversos , Sacarose na Dieta/administração & dosagem , Sacarose na Dieta/efeitos adversos , Humanos , Hipotálamo/citologia , Hipotálamo/patologia , Injeções Intraventriculares , Leptina/genética , Masculino , Melanocortinas/metabolismo , Hormônios Estimuladores de Melanócitos/administração & dosagem , Camundongos , Camundongos Knockout , Neurônios/efeitos dos fármacos , Neurônios/metabolismo , Oligodendroglia/efeitos dos fármacos , Oligodendroglia/metabolismo , RNA-Seq , Receptor Tipo 4 de Melanocortina/genética , Receptores de Melanocortina/antagonistas & inibidores , Receptores de Melanocortina/metabolismo , Indução de Remissão/métodos , Transdução de Sinais/efeitos dos fármacos , Análise de Célula Única , Técnicas Estereotáxicas , Transcriptoma/efeitos dos fármacos
4.
Life Sci ; 258: 118217, 2020 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-32768575

RESUMO

AIMS: Astrocytes expressing the aquaporin-4 (AQP4) water channel are pathogenic, disease specific immunoglobulins (IgG) found in neuromyelitis optica spectrum disorder (NMOSD), referred to as NMO-IgG, which targets astrocytic AQP4. The interleukin-6 (IL-6) signaling when astrocytes were exposed to NMO-IgG present in the serum of NMOSD patients was evaluated. MAIN METHODS: Serum or human-IgG from NMOSD or healthy controls were exposed to astrocytes. The selectivity and immuno-pathological consequences of Ig binding to surface epitopes were measured by confocal microscopy. Astrocytes were exposed to medium, IL-6, soluble IL-6 receptor (sIL-6R), IL-6 + sIL-6R (IL-6/R), NMO-IgG or control-IgG, NMO-IgG + IL-6/R. The expression of key proteins in IL-6 signaling pathway, IL-6 cytokine and mRNA levels were evaluated by western blotting, enzyme-linked immunosorbent assay and quantitative polymerase chain reaction, respectively. KEY FINDINGS: Serum or NMO-IgG from NMOSD patients both induced the rapid downregulation of AQP4 expression on the surface of astrocytes. Stimulation of astrocytes with NMO-IgG, IL-6/R, and NMO-IgG + IL-6/R resulted in the enhancement of IL-6 mRNA expression. Meanwhile, the exogenous addition of NMO-IgG elicited an inflammatory transcriptional response that involved signaling through the Janus kinase/signal transducer and activator of transcription 3 (JAK/STAT3) pathway. Inhibition of the IL-6/JAK/STAT3 pathway with the JAK1/2 specific inhibitor, AZD1480, reversed the associated increase of IL-6. SIGNIFICANCE: Our findings suggest that NMO-IgG can stimulate the astrocytic JAK1/2/STAT3-dependent inflammatory response, which represents one of the important events in NMO pathogenesis. Inhibition of the JAK1/2 signaling pathway may be a novel promising therapy for NMOSD.


Assuntos
Astrócitos/metabolismo , Imunoglobulina G/sangue , Interleucina-6/metabolismo , Janus Quinases/metabolismo , Neuromielite Óptica/sangue , Fator de Transcrição STAT3/metabolismo , Adulto , Idoso , Animais , Astrócitos/efeitos dos fármacos , Autoanticorpos/sangue , Autoanticorpos/farmacologia , Células Cultivadas , Feminino , Humanos , Imunoglobulina G/farmacologia , Interleucina-6/agonistas , Masculino , Pessoa de Meia-Idade , Ratos , Ratos Wistar , Fator de Transcrição STAT3/agonistas , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/fisiologia , Adulto Jovem
5.
Nature ; 583(7817): 603-608, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32641832

RESUMO

Astrocytes take up glucose from the bloodstream to provide energy to the brain, thereby allowing neuronal activity and behavioural responses1-5. By contrast, astrocytes are under neuronal control through specific neurotransmitter receptors5-7. However, whether the activation of astroglial receptors can directly regulate cellular glucose metabolism to eventually modulate behavioural responses is unclear. Here we show that activation of mouse astroglial type-1 cannabinoid receptors associated with mitochondrial membranes (mtCB1) hampers the metabolism of glucose and the production of lactate in the brain, resulting in altered neuronal functions and, in turn, impaired behavioural responses in social interaction assays. Specifically, activation of astroglial mtCB1 receptors reduces the phosphorylation of the mitochondrial complex I subunit NDUFS4, which decreases the stability and activity of complex I. This leads to a reduction in the generation of reactive oxygen species by astrocytes and affects the glycolytic production of lactate through the hypoxia-inducible factor 1 pathway, eventually resulting in neuronal redox stress and impairment of behavioural responses in social interaction assays. Genetic and pharmacological correction of each of these effects abolishes the effect of cannabinoid treatment on the observed behaviour. These findings suggest that mtCB1 receptor signalling can directly regulate astroglial glucose metabolism to fine-tune neuronal activity and behaviour in mice.


Assuntos
Astrócitos/metabolismo , Metabolismo Energético , Glucose/metabolismo , Mitocôndrias/metabolismo , Receptor CB1 de Canabinoide/metabolismo , Animais , Astrócitos/citologia , Astrócitos/efeitos dos fármacos , Agonistas de Receptores de Canabinoides/farmacologia , Células Cultivadas , Dronabinol/farmacologia , Complexo I de Transporte de Elétrons/química , Complexo I de Transporte de Elétrons/metabolismo , Metabolismo Energético/efeitos dos fármacos , Glicólise/efeitos dos fármacos , Humanos , Fator 1 Induzível por Hipóxia/metabolismo , Ácido Láctico/metabolismo , Masculino , Camundongos , Mitocôndrias/efeitos dos fármacos , Membranas Mitocondriais/metabolismo , Oxirredução , Fosforilação , Espécies Reativas de Oxigênio/metabolismo , Receptor CB1 de Canabinoide/agonistas , Comportamento Social
6.
Life Sci ; 257: 118037, 2020 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-32622942

RESUMO

Palmitoylethanolamide (PEA) is an endogenous lipid mediator that, also by blunting astrocyte activation, demonstrated beneficial properties in several in vitro and in vivo models of Alzheimer's disease (AD). In the present study, we used astrocyte-neuron co-cultures from 3xTg-AD mouse (i.e. an animal model of AD) cerebral cortex to further investigate on the role of astrocytes in PEA-induced neuroprotection. To this aim, we evaluated the number of viable cells, apoptotic nuclei, microtubule-associated protein-2 (MAP2) positive cells and morphological parameters in cortical neurons co-cultured with cortical astrocytes pre-exposed, or not, to Aß42 (0.5 µM; 24 h) or PEA (0.1 µM; 24 h). Pre-exposure of astrocytes to Aß42 failed to affect the viability, the number of neuronal apoptotic nuclei, MAP2 positive cell number, neuritic aggregations/100 µm, dendritic branches per neuron, the neuron body area, the length of the longest dendrite and number of neurites/neuron in 3xTg-AD mouse astrocyte-neuron co-cultures. Compared to neurons from wild-type (non-Tg) mouse co-cultures, 3xTg-AD mouse neurons co-cultured with astrocytes from this mutant mice displayed higher number of apoptotic nuclei, lower MAP2 immunoreactivity and several morphological changes. These signs of neuronal suffering were significantly counteracted when the 3xTg-AD mouse cortical neurons were co-cultured with 3xTg-AD mouse astrocytes pre-exposed to PEA. The present data suggest that in astrocyte-neuron co-cultures from 3xTg-AD mice, astrocytes contribute to neuronal damage and PEA, by possibly counteracting reactive astrogliosis, improved neuronal survival. These findings further support the role of PEA as a possible new therapeutic opportunity in AD treatment.


Assuntos
Astrócitos/efeitos dos fármacos , Astrócitos/metabolismo , Etanolaminas/farmacologia , Ácidos Palmíticos/farmacologia , Doença de Alzheimer/tratamento farmacológico , Doença de Alzheimer/metabolismo , Peptídeos beta-Amiloides/metabolismo , Animais , Sobrevivência Celular/efeitos dos fármacos , Córtex Cerebral/metabolismo , Técnicas de Cocultura , Modelos Animais de Doenças , Etanolaminas/metabolismo , Gliose , Humanos , Masculino , Camundongos , Camundongos Transgênicos , Proteínas Associadas aos Microtúbulos , Neurônios/efeitos dos fármacos , Fármacos Neuroprotetores/farmacologia , Ácidos Palmíticos/metabolismo , Proteínas tau/metabolismo
7.
Life Sci ; 258: 118140, 2020 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-32730838

RESUMO

AIMS: This study was performed to investigate the expression profile of cytochrome P450 (CYP) isoforms and effects of polycyclic aromatic hydrocarbons (PAHs) and antiepileptic drugs on CYP1 expression in human astrocytoma MOG-G-CCM cells. MAIN METHODS: CYP1A1 and CYP1B1 expression were determined by quantitative real-time polymerase chain reaction, Western blotting, and immunocytochemistry. KEY FINDINGS: MOG-G-CCM cells expressed various CYP isoforms. Among the CYP isoforms analyzed, CYP1B1 showed the highest expression level, followed by CYP1A1. Furthermore, CYP1B1 was localized in both the endoplasmic reticulum and mitochondria. 3-Methylcholanthrene (3-MC), benz[a]anthracene (B[a]A), benzo[a]pyrene (B[a]P), and valproic acid (VPA) increased the expression of CYP1B1 and CYP1A1. The potent aryl hydrocarbon receptor antagonist GNF351 significantly suppressed the 3-MC- and VPA-mediated upregulation of CYP1B1 and CYP1A1. In addition, VPA potentiated the induction of CYP1B1 and CYP1A1 by 3-MC, B[a]A, and B[a]P, although the augmentation of CYP1A1 was more remarkable than that of CYP1B1. In contrast, other antiepileptic drugs (carbamazepine, lamotrigine, levetiracetam, phenytoin) did not affect the 3-MC-mediated upregulation of CYP1B1 and CYP1A1. VPA is known to act as a histone deacetylase (HDAC) inhibitor. Therefore, the effects of trichostatin A, a representative HDAC inhibitor, on CYP1 induction by 3-MC were examined. Trichostatin A enhanced the 3-MC-mediated upregulation of CYP1A1 but not CYP1B1. SIGNIFICANCE: These results partially indicated that VPA may augment the PAH-mediated induction of CYP1B1 and CYP1A1 through the activation of transcription by HDAC inhibition.


Assuntos
Anticonvulsivantes/farmacologia , Citocromo P-450 CYP1A1/genética , Citocromo P-450 CYP1B1/genética , Hidrocarbonetos Policíclicos Aromáticos/farmacologia , Regulação para Cima/efeitos dos fármacos , Ácido Valproico/farmacologia , Astrócitos/efeitos dos fármacos , Astrócitos/metabolismo , Linhagem Celular Tumoral , Humanos , Transcriptoma/efeitos dos fármacos
8.
Toxicol Lett ; 331: 188-199, 2020 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-32569805

RESUMO

Methamphetamine (METH) is a highly addictive psychostimulant drug whose abuse can cause many health complications. Our previous studies have shown that METH exposure increases α-synuclein (α-syn) expression. Recently, it was shown that α-syn could be transferred from neurons to astrocytes via exosomes. However, the specific role of astrocytes in α-syn pathology involved in METH neurotoxicity remains unclear. The objective of this study was to determine whether exosomes derived from METH-treated neurons contain pathological α-syn and test the hypothesis that exosomes can transfer pathological α-syn from neurons to astrocytes. To this end, using animal and cell line coculture models, we show that exosomes isolated from METH-treated SH-SY5Y cells contained pathological α-syn. Furthermore, the addition of METH exosomes to the medium of primary cultured astrocytes induced α-syn aggregation and inflammatory responses in astrocytes. Then, we evaluated changes in nuclear receptor related 1 protein (Nurr1) expression and the levels of inflammatory cytokines in primary cultured astrocytes exposed to METH or α-syn. We found that METH or α-syn exposure decreased Nurr1 expression and increased proinflammatory cytokine expression in astrocytes. Our results indicate that α-syn can be transferred from neuronal cells to astrocytes through exosomes. When internalized α-syn accumulated in astrocytes, the cells produced inflammatory responses. Nurr1 may play a crucial role in this process and could be a therapeutic target for inflammatory damage caused by METH.


Assuntos
Astrócitos/efeitos dos fármacos , Estimulantes do Sistema Nervoso Central/toxicidade , Exossomos/metabolismo , Metanfetamina/toxicidade , Neurônios/efeitos dos fármacos , Síndromes Neurotóxicas/metabolismo , alfa-Sinucleína/metabolismo , Animais , Astrócitos/imunologia , Astrócitos/metabolismo , Linhagem Celular Tumoral , Técnicas de Cocultura , Citocinas/metabolismo , Hipocampo/citologia , Humanos , Injeções Intraperitoneais , Masculino , Camundongos Endogâmicos C57BL , Neurônios/imunologia , Neurônios/metabolismo , Síndromes Neurotóxicas/imunologia , Membro 2 do Grupo A da Subfamília 4 de Receptores Nucleares/genética , Cultura Primária de Células , Sinucleinopatias/imunologia , Sinucleinopatias/metabolismo
9.
Int J Nanomedicine ; 15: 3649-3667, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32547020

RESUMO

Introduction: The polyphenolic spice and food coloring ingredient curcumin has beneficial effects in a broad variety of inflammatory diseases. Amongst them, curcumin has been shown to attenuate microglia reaction and prevent from glial scar formation in spinal cord and brain injuries. Methods: We developed a protocol for the efficient encapsulation of curcumin as a model for anti-inflammatory drugs yielding long-term stable, non-toxic liposomes with favorable physicochemical properties. Subsequently, we evaluate the effects of liposomal curcumin in experimental models for neuroinflammation and reactive astrogliosis. Results: We could show that liposomal curcumin can efficiently reduce the reactivity of human microglia and astrocytes and preserve tissue integrity of murine organotypic cortex slices. Discussion and Perspective: In perspective, we want to administer this curcumin formulation in brain implant coatings to prevent neuroinflammation and glial scar formation as foreign body responses of the brain towards implanted materials.


Assuntos
Encéfalo/patologia , Curcumina/uso terapêutico , Gliose/tratamento farmacológico , Inflamação/tratamento farmacológico , Neuroglia/patologia , Animais , Anti-Inflamatórios/farmacologia , Astrócitos/efeitos dos fármacos , Astrócitos/ultraestrutura , Encéfalo/efeitos dos fármacos , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Curcumina/farmacologia , Humanos , Inflamação/patologia , Lipopolissacarídeos/farmacologia , Lipossomos , Camundongos , Microglia/efeitos dos fármacos , Microglia/ultraestrutura , Neuroglia/efeitos dos fármacos
10.
Acta Cir Bras ; 35(4): e202000406, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32578724

RESUMO

PURPOSE: To investigate the role of Rosmarinic acid (RA) in the prevention of traumatic brain injury and the immunohistochemical analysis of IBA-1 and GFAP expressions. METHODS: Healthy male rats were randomly divided into 3 groups consisting of 10 rats. Groups were as follows; control group, traumatic brain injury (TBI) group, and TBI+RA group. After traumatic brain injury, blood samples were taken from the animals and analyzed with various biochemical markers. And then IBA-1 and GFAP expressions were evaluated immunohistochemically. RESULTS: Significant results were obtained in all biochemical parameters between groups. Immunohistochemical sections showed IBA-1 not only in microglia and macrophage activity but also in degenerative neurons in blood vessel endothelial cells. However, GFAP reaction and post-traumatic rosmarinic acid administration showed positive expression in astrocytes with regular structure around the blood vessel. CONCLUSION: Rosmarinic acid in blood vessel endothelial cells showed that preserving the integrity of astrocytic structure in the blood brain barrier may be an important antioxidant.


Assuntos
Lesões Encefálicas Traumáticas/prevenção & controle , Proteínas de Ligação ao Cálcio/análise , Cinamatos/farmacologia , Craniotomia/métodos , Depsídeos/farmacologia , Proteína Glial Fibrilar Ácida/análise , Proteínas dos Microfilamentos/análise , Fármacos Neuroprotetores/farmacologia , Animais , Astrócitos/efeitos dos fármacos , Lesões Encefálicas Traumáticas/patologia , Lesões Encefálicas Traumáticas/cirurgia , Glutationa Peroxidase/análise , Imuno-Histoquímica , Masculino , Malondialdeído/análise , Distribuição Aleatória , Ratos Sprague-Dawley , Valores de Referência , Reprodutibilidade dos Testes
11.
Aging (Albany NY) ; 12(11): 10035-10040, 2020 06 13.
Artigo em Inglês | MEDLINE | ID: mdl-32534451

RESUMO

Cell senescence is a process that causes growth arrest and the release of a senescence associated secretory phenotype (SASP), characterized by secretion of chemokines, cytokines, cell growth factors and metalloproteases, leading to a tissue condition that may precipitate cancers and neurodegenerative processes. With the recent pandemic of coronavirus, senolytic drugs are being considered as possible therapeutic tools to reduce the virulence of SARS-CoV-2. In the last few years, our research group showed that lithium carbonate at microdose levels was able to stabilize memory and change neuropathological characteristics of Alzheimer's disease (AD). In the present work, we present evidence that low-dose lithium can reduce the SASP of human iPSCs-derived astrocytes following acute treatment, suggesting that microdose lithium could protect cells from senescence and development of aging-related conditions. With the present findings, a perspective of the potential use of low-dose lithium in old patients from the "high risk group" for COVID-19 (with hypertension, diabetes and chronic obstructive pulmonary disease) is presented.


Assuntos
Astrócitos/efeitos dos fármacos , Infecções por Coronavirus/tratamento farmacológico , Compostos de Lítio/uso terapêutico , Pneumonia Viral/tratamento farmacológico , Células Cultivadas , Avaliação Pré-Clínica de Medicamentos , Humanos , Pandemias
12.
Toxicology ; 441: 152525, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32540480

RESUMO

There is considerable interest in gene and environment interactions in neurodegenerative diseases. The HFE (homeostatic iron regulator) gene variant (H63D) is highly prevalent in the population and has been investigated as a disease modifier in multiple neurodegenerative diseases. We have developed a mouse model to interrogate the impact of this gene variant in a model of paraquat toxicity. Using primary astrocytes, we found that the H67D-Hfe(equivalent of the human H63D variant) astrocytes are less vulnerable than the WT-Hfe astrocytes to paraquat-induced cell death, mitochondrial damage, and cellular senescence. We hypothesized that the Hfe variant-associated protection is a result of the activation of the Nrf2 antioxidant defense system and found a significant increase in Nrf2 levels after paraquat exposure in the H67D-Hfe astrocytes than the WT-Hfe astrocytes. Moreover, decreasing Nrf2 by molecular or pharmaceutical manipulation resulted in increased vulnerability to paraquat in the H67D-Hfe astrocytes. To further elucidate the role of Hfe variant genotype in neuroprotection mediated by astrocytes, we added media from the paraquat-treated astrocytes to differentiated SH-SY5Y neuroblastoma cells and found a significantly larger reduction in the viability when treated with WT-Hfe astrocyte media than the H67D-Hfe astrocyte media possibly due to higher secretion of IL-6 observed in the WT-Hfe astrocytes. To further explore the mechanism of Nrf2 protection, we measured NQO1, the Nrf2-mediated antioxidant, in primary astrocytes and found a significantly higher NQO1 level in the H67D-Hfe astrocytes. To consider the translational potential of our findings, we utilized the PPMI (Parkinson's Progression Markers Initiative) clinical database and found that, consistent with the mouse study, H63D-HFE carriers had a significantly higher NQO1 level in the CSF than the WT-HFE carriers. Consistent with our previous reports on H63D-HFE in disease, these data further suggest that HFE genotype in the human population impacts the antioxidant defense system and can therefore alter pathogenesis.


Assuntos
Proteína da Hemocromatose/genética , Fator 2 Relacionado a NF-E2/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Animais , Astrócitos/efeitos dos fármacos , Morte Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Senescência Celular/efeitos dos fármacos , Feminino , Genótipo , Proteína da Hemocromatose/efeitos dos fármacos , Proteína da Hemocromatose/metabolismo , Humanos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Paraquat/toxicidade
13.
J Pharmacol Exp Ther ; 374(3): 354-365, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32561686

RESUMO

The development of neuropharmaceutical gene delivery systems requires strategies to obtain efficient and effective brain targeting as well as blood-brain barrier (BBB) permeability. A brain-targeted gene delivery system based on a transferrin (Tf) and cell-penetrating peptide (CPP) dual-functionalized liposome, CPP-Tf-liposome, was designed and investigated for crossing BBB and permeating into the brain. We selected three sequences of CPPs [melittin, Kaposi fibroblast growth factor (kFGF), and penetration accelerating sequence-R8] and compared their ability to internalize into the cells and, subsequently, improve the transfection efficiency. Study of intracellular uptake indicated that liposomal penetration into bEnd.3 cells, primary astrocytes, and primary neurons occurred through multiple endocytosis pathways and surface modification with Tf and CPP enhanced the transfection efficiency of the nanoparticles. A coculture in vitro BBB model reproducing the in vivo anatomophysiological complexity of the biologic barrier was developed to characterize the penetrating properties of these designed liposomes. The dual-functionalized liposomes effectively crossed the in vitro barrier model followed by transfecting primary neurons. Liposome tissue distribution in vivo indicated superior ability of kFGF-Tf-liposomes to overcome BBB and reach brain of the mice after single intravenous administration. These findings demonstrate the feasibility of using strategically designed liposomes by combining Tf receptor targeting with enhanced cell penetration as a potential brain gene delivery vector. SIGNIFICANCE STATEMENT: Rational synthesis of efficient brain-targeted gene carrier included modification of liposomes with a target-specific ligand, transferrin, and with cell-penetrating peptide to enhance cellular internalization. Our study used an in vitro triple coculture blood-brain barrier (BBB) model as a tool to characterize the permeability across BBB and functionality of designed liposomes prior to in vivo biodistribution studies. Our study demonstrated that rational design and characterization of BBB permeability are efficient strategies for development of brain-targeted gene carriers.


Assuntos
Encéfalo/efeitos dos fármacos , Lipossomos/administração & dosagem , Animais , Astrócitos/efeitos dos fármacos , Astrócitos/metabolismo , Barreira Hematoencefálica/metabolismo , Peptídeos Penetradores de Células/administração & dosagem , Sistemas de Liberação de Medicamentos/métodos , Feminino , Técnicas de Transferência de Genes , Terapia Genética/métodos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Nanopartículas/administração & dosagem , Neurônios/efeitos dos fármacos , Neurônios/metabolismo , Ratos Sprague-Dawley , Distribuição Tecidual/fisiologia , Transferrina/administração & dosagem
14.
Ecotoxicol Environ Saf ; 201: 110799, 2020 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-32544743

RESUMO

Mercury (Hg) is an environmental contaminant that poses great risk to human health. However, it is still widely used in artisanal gold-mining enterprises around the world, especially in developing countries. Methylmercury (MeHg) is produced environmentally by biomethylation of inorganic Hg present in water sediments, leading to its subsequent accumulation in the aquatic food chain. Due to its high metabolic rate, the Central Nervous System (CNS) is one of the main targets of MeHg. In the present study, we investigate the impact of chronic MeHg intoxication on NADPH diaphorase (NADPH-d) activity and astrocyte mobilization in the visual cortex of the rat. After 60 days of MeHg administration by oral gavage (0.04 mg/kg/day), tissue samples containing the visual cortex were submitted to measurements of Hg levels, NADPH-d activity, and GFAP immunohistochemistry for identification of astrocytes. MeHg intoxication was associated with increased Hg deposits and with reduced NADPH-d neuropil reactivity in the visual cortex. A morphometric analysis suggested that NADPH-d-positive neurons were mostly spared from MeHg harmful action and intoxicated animals had astrocytic activation similar to the control group. The decrease in NADPH-d neuropil reactivity may be due to the negative effect of chronic MeHg poisoning on both the synthesis and transport of this enzyme in afferent pathways to the visual cortex. The relative resistance of NADPH-d-reactive neurons to chronic MeHg intoxication may be associated with peculiarities in cell metabolism or to a protective role of nitric oxide, safeguarding those neurons from Hg deleterious effects.


Assuntos
Astrócitos/efeitos dos fármacos , Poluentes Ambientais/toxicidade , Compostos de Metilmercúrio/toxicidade , NADPH Desidrogenase/metabolismo , Neurônios/efeitos dos fármacos , Córtex Visual/efeitos dos fármacos , Animais , Astrócitos/enzimologia , Comportamento Animal/efeitos dos fármacos , Poluentes Ambientais/metabolismo , Ouro , Humanos , Masculino , Compostos de Metilmercúrio/metabolismo , Mineração , Neurônios/enzimologia , Ratos , Ratos Wistar , Córtex Visual/enzimologia , Córtex Visual/patologia
15.
Nat Commun ; 11(1): 2484, 2020 05 18.
Artigo em Inglês | MEDLINE | ID: mdl-32424276

RESUMO

DNA damage contributes to brain aging and neurodegenerative diseases. However, the factors stimulating DNA repair to stave off functional decline remain obscure. We show that HDAC1 modulates OGG1-initated 8-oxoguanine (8-oxoG) repair in the brain. HDAC1-deficient mice display age-associated DNA damage accumulation and cognitive impairment. HDAC1 stimulates OGG1, a DNA glycosylase known to remove 8-oxoG lesions that are associated with transcriptional repression. HDAC1 deficiency causes impaired OGG1 activity, 8-oxoG accumulation at the promoters of genes critical for brain function, and transcriptional repression. Moreover, we observe elevated 8-oxoG along with reduced HDAC1 activity and downregulation of a similar gene set in the 5XFAD mouse model of Alzheimer's disease. Notably, pharmacological activation of HDAC1 alleviates the deleterious effects of 8-oxoG in aged wild-type and 5XFAD mice. Our work uncovers important roles for HDAC1 in 8-oxoG repair and highlights the therapeutic potential of HDAC1 activation to counter functional decline in brain aging and neurodegeneration.


Assuntos
Envelhecimento/patologia , Doença de Alzheimer/patologia , Encéfalo/patologia , Dano ao DNA , DNA Glicosilases/metabolismo , Histona Desacetilase 1/metabolismo , Estresse Oxidativo , Acetilação , Envelhecimento/genética , Doença de Alzheimer/complicações , Doença de Alzheimer/fisiopatologia , Animais , Astrócitos/efeitos dos fármacos , Astrócitos/metabolismo , Astrócitos/patologia , Sequência de Bases , Benzofenonas/farmacologia , Cognição/efeitos dos fármacos , Transtornos Cognitivos/complicações , Transtornos Cognitivos/patologia , Regulação para Baixo/efeitos dos fármacos , Regulação para Baixo/genética , Ontologia Genética , Guanina/análogos & derivados , Guanina/metabolismo , Memória/efeitos dos fármacos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Neurônios/efeitos dos fármacos , Neurônios/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Regiões Promotoras Genéticas/genética
16.
J Toxicol Sci ; 45(5): 271-280, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32404559

RESUMO

Environmental neurotoxins such as paraquat (PQ), manganese, and 1-1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) are associated with a higher risk of Parkinson's disease (PD). These parkinsonian toxins exert certain common toxicological effects on astroglia; however, their role in the regulatory functions of astroglial secretory proteins remains unclear. In a previous study, we observed that secretogranin II (SCG2) and secretogranin III (SCG3), which are important components of the regulated secretory pathway, were elevated in PQ-activated U118 astroglia. In the current study, we used the parkinsonian toxins dopamine (DA), active metabolite of MPTP (MPP+), MnCl2, and lipopolysaccharide (LPS) as inducers, and studied the potential regulation of SCG2 and SCG3. Our results showed that all the parkinsonian toxins except LPS affected astroglial viability but did not cause apoptosis. Exposure to DA, MPP+, and MnCl2 upregulated glial fibrillary acidic protein (GFAP), a marker for astrocyte activation, and stimulated the levels of several astrocytic-derived factors. Further, DA, MPP+, and MnCl2 exposure impeded astroglial cell cycle progression. Moreover, the expression of SCG3 was elevated, while its exosecretion was inhibited in astroglia activated by parkinsonian toxins. The level of SCG2 remained unchanged. In combination with our previous findings, the results of this study indicate that SCG3 may act as a cofactor in astrocyte activation stimulated by various toxins, and the regulation of SCG3 could be involved in the toxicological mechanism by which parkinsonian toxins affect astroglia.


Assuntos
Astrócitos/efeitos dos fármacos , Astrócitos/metabolismo , Cromograninas/fisiologia , Intoxicação por MPTP/complicações , Neurotoxinas/toxicidade , Doença de Parkinson Secundária/etiologia , Ciclo Celular/efeitos dos fármacos , Cloretos/efeitos adversos , Cloretos/toxicidade , Cromograninas/metabolismo , Dopamina/administração & dosagem , Dopamina/toxicidade , Proteína Glial Fibrilar Ácida/metabolismo , Humanos , Compostos de Manganês/efeitos adversos , Paraquat/toxicidade , Secretogranina II/metabolismo , Secretogranina II/fisiologia , Células Tumorais Cultivadas , Regulação para Cima/efeitos dos fármacos
17.
PLoS One ; 15(5): e0229702, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32413082

RESUMO

The Glymphatic System (GS) has been proposed as a mechanism to clear brain tissue from waste. Its dysfunction might lead to several brain pathologies, including the Alzheimer's disease. A key component of the GS and brain tissue water circulation is the astrocyte which is regulated by acquaporin-4 (AQP4), a membrane-bound water channel on the astrocytic end-feet. Here we investigated the potential of diffusion MRI to monitor astrocyte activity in a mouse brain model through the inhibition of AQP4 channels with TGN-020. Upon TGN-020 injection, we observed a significant decrease in the Sindex, a diffusion marker of tissue microstructure, and a significant increase of the water diffusion coefficient (sADC) in cerebral cortex and hippocampus compared to saline injection. These results indicate the suitability of diffusion MRI to monitor astrocytic activity in vivo and non-invasively.


Assuntos
Aquaporina 4/metabolismo , Astrócitos/metabolismo , Encéfalo/efeitos dos fármacos , Niacinamida/análogos & derivados , Tiadiazóis/farmacologia , Animais , Aquaporina 4/antagonistas & inibidores , Astrócitos/efeitos dos fármacos , Encéfalo/citologia , Encéfalo/diagnóstico por imagem , Encéfalo/metabolismo , Imagem de Difusão por Ressonância Magnética , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Niacinamida/farmacologia
18.
Invest Ophthalmol Vis Sci ; 61(5): 29, 2020 05 11.
Artigo em Inglês | MEDLINE | ID: mdl-32421147

RESUMO

Purpose: Matrix metalloproteinases (MMPs) are involved in extracellular matrix (ECM) maintenance and remodeling. The present study aimed to determine whether transforming growth factor (TGF)-ß2 regulates MMP-2 and MMP-9 levels and activities in astrocytes derived from the optic nerve head (ONH) and the role of statins in such modulation. Methods: Primary astrocytes cultured from the lamina cribrosa of human donor ONHs were incubated with three types of statins (5 µg/mL) for 1 hour followed by recombinant TGF-ß2 (5 ng/mL) for various periods to test their effects. Levels and activities of MMP-2 and MMP-9 in astrocytes in vitro were determined by western blotting and zymography, respectively. Levels of phosphorylated myosin phosphatase target subunit 1 (MYPT1) in astrocyte lysates were determined by western blotting, and those of phosphorylated myosin light chain (MLC) were determined by western blotting and immunocytochemistry. Results: MMP-2 and MMP-9 levels were upregulated by TGF-ß2 in human ONH astrocytes. Prior incubation with simvastatin, lovastatin, and atorvastatin inhibited TGF-ß2-mediated MMP-2 and MMP-9 expression and activities. Prior incubation with statins downregulated the TGF-ß2-induced phosphorylation of MYPT1 and MLC, which are downstream substrates of RhoA and ROCKs. Conclusions: Statins inhibited the TGF-ß2-mediated regulation of MMP-2 and MMP-9 by inhibiting the RhoA/ROCK signaling pathway. Considering the role of MMP in ECM remodeling, the present findings support the notion that statins positively impact ECM remodeling within the ONH.


Assuntos
Astrócitos/efeitos dos fármacos , Regulação Enzimológica da Expressão Gênica/fisiologia , Inibidores de Hidroximetilglutaril-CoA Redutases/farmacologia , Metaloproteinase 2 da Matriz/genética , Metaloproteinase 9 da Matriz/genética , Fator de Crescimento Transformador beta2/antagonistas & inibidores , Quinases Associadas a rho/antagonistas & inibidores , Proteína rhoA de Ligação ao GTP/antagonistas & inibidores , Adulto , Astrócitos/enzimologia , Atorvastatina/farmacologia , Western Blotting , Células Cultivadas , Feminino , Humanos , Imuno-Histoquímica , Lovastatina/farmacologia , Masculino , Metaloproteinase 2 da Matriz/metabolismo , Metaloproteinase 9 da Matriz/metabolismo , Pessoa de Meia-Idade , Fosfatase de Miosina-de-Cadeia-Leve/metabolismo , Disco Óptico/citologia , Fosforilação , Transdução de Sinais/efeitos dos fármacos , Sinvastatina/farmacologia , Fator de Crescimento Transformador beta2/farmacologia
19.
J Neurosci ; 40(23): 4609-4619, 2020 06 03.
Artigo em Inglês | MEDLINE | ID: mdl-32350039

RESUMO

Idebenone is a synthetic quinone that on reduction in cells can bypass mitochondrial Complex I defects by donating electrons to Complex III. The drug is used clinically to treat the Complex I disease Leber's hereditary optic neuropathy (LHON), but has been less successful in clinical trials for other neurodegenerative diseases. NAD(P)H:quinone oxidoreductase 1 (NQO1) appears to be the main intracellular enzyme catalyzing idebenone reduction. However, NQO1 is not universally expressed by cells of the brain. Using primary rat cortical cells pooled from both sexes, we tested the hypotheses that the level of endogenous NQO1 activity limits the ability of neurons, but not astrocytes, to use idebenone as an electron donor to support mitochondrial respiration. We then tested the prediction that NQO1 induction by pharmacological activation of the transcription factor nuclear erythroid 2-related factor 2 (Nrf2) enables idebenone to bypass Complex I in cells with poor NQO1 expression. We found that idebenone stimulated respiration by astrocytes but reduced the respiratory capacity of neurons. Importantly, idebenone supported mitochondrial oxygen consumption in the presence of a Complex I inhibitor in astrocytes but not neurons, and this ability was reversed by inhibiting NQO1. Conversely, recombinant NQO1 delivery to neurons prevented respiratory impairment and conferred Complex I bypass activity. Nrf2 activators failed to increase NQO1 in neurons, but carnosic acid induced NQO1 in COS-7 cells that expressed little endogenous enzyme. Carnosic acid-idebenone combination treatment promoted NQO1-dependent Complex I bypass activity in these cells. Thus, combination drug strategies targeting NQO1 may promote the repurposing of idebenone for additional disorders.SIGNIFICANCE STATEMENT Idebenone is used clinically to treat loss of visual acuity in Leber's hereditary optic neuropathy. Clinical trials for several additional diseases have failed. This study demonstrates a fundamental difference in the way idebenone affects mitochondrial respiration in cortical neurons compared with cortical astrocytes. Cortical neurons are unable to use idebenone as a direct mitochondrial electron donor due to NQO1 deficiency. Our results suggest that idebenone behaves as an NQO1-dependent prodrug, raising the possibility that lack of neuronal NQO1 activity has contributed to the limited efficacy of idebenone in neurodegenerative disease treatment. Combination therapy with drugs able to safely induce NQO1 in neurons, as well as other brain cell types, may be able to unlock the neuroprotective therapeutic potential of idebenone or related quinones.


Assuntos
Antioxidantes/farmacologia , Astrócitos/enzimologia , Respiração Celular/fisiologia , Mitocôndrias/enzimologia , NAD(P)H Desidrogenase (Quinona)/metabolismo , Ubiquinona/análogos & derivados , Animais , Animais Recém-Nascidos , Astrócitos/efeitos dos fármacos , Células COS , Respiração Celular/efeitos dos fármacos , Células Cultivadas , Chlorocebus aethiops , Relação Dose-Resposta a Droga , Ativação Enzimática/efeitos dos fármacos , Ativação Enzimática/fisiologia , Feminino , Masculino , Mitocôndrias/efeitos dos fármacos , Ratos , Ratos Sprague-Dawley , Ubiquinona/farmacologia
20.
J Med Chem ; 63(11): 6164-6178, 2020 06 11.
Artigo em Inglês | MEDLINE | ID: mdl-32345019

RESUMO

Antagonists for the ATP-gated ion channel receptor P2X1 have potential as antithrombotics and for treating hyperactive bladder and inflammation. In this study, salicylanilide derivatives were synthesized based on a screening hit. P2X1 antagonistic potency was assessed in 1321N1 astrocytoma cells stably transfected with the human P2X1 receptor by measuring inhibition of the ATP-induced calcium influx. Structure-activity relationships were analyzed, and selectivity versus other P2X receptor subtypes was assessed. The most potent compounds, N-[3,5-bis(trifluoromethyl)phenyl]-5-chloro-2-hydroxybenzamide (1, IC50 0.0192 µM) and N-[3,5-bis(trifluoromethyl)phenyl]-4-chloro-2-hydroxybenzamide (14, IC50 0.0231 µM), displayed >500-fold selectivity versus P2X2 and P2X3, and 10-fold selectivity versus P2X4 and P2X7 receptors, and inhibited collagen-induced platelet aggregation. They behaved as negative allosteric modulators, and molecular modeling studies suggested an extracellular binding site. Besides selective P2X1 antagonists, compounds with ancillary P2X4 and/or P2X7 receptor inhibition were discovered. These compounds represent the first potent, non-acidic, allosteric P2X1 receptor antagonists reported to date.


Assuntos
Antagonistas do Receptor Purinérgico P2X/química , Receptores Purinérgicos P2X1/metabolismo , Salicilanilidas/química , Regulação Alostérica/efeitos dos fármacos , Astrócitos/citologia , Astrócitos/efeitos dos fármacos , Astrócitos/metabolismo , Sítios de Ligação , Plaquetas/citologia , Plaquetas/efeitos dos fármacos , Plaquetas/metabolismo , Cálcio/metabolismo , Linhagem Celular , Colágeno , Avaliação Pré-Clínica de Medicamentos , Humanos , Simulação de Dinâmica Molecular , Agregação Plaquetária/efeitos dos fármacos , Isoformas de Proteínas/antagonistas & inibidores , Isoformas de Proteínas/metabolismo , Antagonistas do Receptor Purinérgico P2X/metabolismo , Antagonistas do Receptor Purinérgico P2X/farmacologia , Receptores Purinérgicos P2X1/química , Salicilanilidas/metabolismo , Salicilanilidas/farmacologia , Relação Estrutura-Atividade
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