RESUMO

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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Recent discoveries have shown that enteric glial cells play an important role in different neurodegenerative disorders, such as Parkinson's disease (PD), which is characterized by motor dysfunctions caused by the progressive loss of dopaminergic neurons in the substance nigra pars compacta and non-motor symptoms including gastrointestinal dysfunction. In this study, we investigated the modulatory effects of the flavonoid rutin on the behavior and myenteric plexuses in a PD animal model and the response of enteric glia. Adult male Wistar rats were submitted to stereotaxic injection with 6-hydroxydopamine or saline, and they were untreated or treated with rutin (10 mg/kg) for 14 days. The ileum was collected to analyze tissue reactivity and immunohistochemistry for neurons (HuC/HuD) and enteric glial cells (S100ß) in the myenteric plexuses. Behavioral tests demonstrated that treatment with rutin improved the motor capacity of parkinsonian animals and improved intestinal transit without interfering with the cell population; rutin treatment modulated the reactivity of the ileal musculature through muscarinic activation, reducing relaxation through the signaling pathway of nitric oxide donors, and increased the longitudinal contractility of the colon musculature in parkinsonian animals. Rutin revealed modulatory activities on the myenteric plexus, bringing relevant answers regarding the effect of the flavonoid in this system and the potential application of PD adjuvant treatment.

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In the central nervous system, astrocytes and microglia contribute to homeostasis, regulating the immune response to infectious agents. Neospora caninum is an obligate intracellular protozoan that infects different animal species and it is encysted in their nervous tissue while triggering an immune response modulated by glia. This study aimed to evaluate the infection of primary cultures of rat glial cells by N. caninum through the catabolites of tryptophan, the expression of inflammatory mediators and the integrity of neural tissue. Infection with this coccidium resulted in morphological and functional changes, particularly astrogliosis and microgliosis, and increased the expression of the inflammatory mediators TNF, IL1ß, IL-10, and arginase, as well as mRNA for CCL5 and CCL2, molecules involved in the CNS chemotaxis. The infection with N. caninum in glial cells also triggered the activation of the tryptophan pathway, characterized by increased kynurenine 2,3 monooxygenase (KMO) mRNA expression, and by the production of the excitotoxin quinolinic acid (QUIN). Moreover, glia-neuron co-cultures, when exposed to the secretome derived from N. caninum infected glial cells, presented greater neurons distribution and formation of neurite extensions, associated to morphological changes in astrocytes compatible with neuro-preservation. Considering that the tryptophan catabolism is associated to immune response, these findings suggest that glial activation in N. caninum infection should be responsible for modulating the inflammatory status in an attempt to restore the nervous system homeostasis, since excessive inflammatory response can cause irreversible damage to tissue preservation.

RESUMO

Glioblastomas (GBMs) are tumors that have a high ability to migrate, invade and proliferate in the healthy tissue, what greatly impairs their treatment. These characteristics are associated with the complex microenvironment, formed by the perivascular niche, which is also composed of several stromal cells including astrocytes, microglia, fibroblasts, pericytes and endothelial cells, supporting tumor progression. Further microglia and macrophages associated with GBMs infiltrate the tumor. These innate immune cells are meant to participate in tumor surveillance and eradication, but they become compromised by GBM cells and exploited in the process. In this review we discuss the context of the GBM microenvironment together with the actions of flavonoids, which have attracted scientific attention due to their pharmacological properties as possible anti-tumor agents. Flavonoids act on a variety of signaling pathways, counteracting the invasion process. Luteolin and rutin inhibit NFκB activation, reducing IL-6 production. Fisetin promotes tumor apoptosis, while inhibiting ADAM expression, reducing invasion. Naringenin reduces tumor invasion by down-regulating metalloproteinases expression. Apigenin and rutin induce apoptosis in C6 cells increasing TNFα, while decreasing IL-10 production, denoting a shift from the immunosuppressive Th2 to the Th1 profile. Overall, flavonoids should be further exploited for glioma therapy.

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Neuroinflammation is one of the most frequently studied topics of neurosciences as it is a common feature in almost all neurological disorders. Although the primary function of neuroinflammation is to protect the nervous system from an insult, the complex and sequential response of activated glial cells can lead to neurological damage. Depending on the type of insults and the time post-insult, the inflammatory response can be neuroprotective, neurotoxic, or, depending on the glial cell types, both. There are multiple pathways activated and many bioactive intermediates are released during neuroinflammation. One of the most common one is the kynurenine pathway, catabolizing tryptophan, which is involved in immune regulation, neuroprotection, and neurotoxicity. Different models have been used to study the kynurenine pathway metabolites to understand their involvements in the development and maintenance of the inflammatory processes triggered by infections. Among them, the parasitic infection Neospora caninum could be used as a relevant model to study the role of the kynurenine pathway in the neuroinflammatory response and the subset of cells involved.

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Neurodegenerative disorders (ND) are characterized by the progressive and irreversible loss of neurons. Alzheimer's Disease (AD) is the most incident age-related ND, in which the presence of a chronic inflammatory compound seems to be related to its pathogenesis. Different stimuli in the central nervous system (CNS) can induce activation, proliferation, and changes in phenotype and glial function, which can be modulated by anti-inflammatory agents. Apigenin (4,5,7-trihydroxyflavone) is a flavonoid found in abundance in many fruits and vegetables, that has shown important effects upon controlling the inflammatory response. This study evaluated the neuroprotective and neuroimmunomodulatory potential of apigenin using in vitro models of neuroinflammation associated with AD. Co-cultures of neurons and glial cells were obtained from the cortex of newborn and embryonic Wistar rats. After 26 days in vitro, cultures were exposed to lipopolysaccharide (LPS; 1 µg/ml), or IL-1ß (10 ng/ml) for 24 h, or to Aß oligomers (500 nM) for 4 h, and then treated with apigenin (1 µM) for further 24 h. It was observed that the treatment with apigenin preserved neurons and astrocytes integrity, determined by Rosenfeld's staining and immunocytochemistry for ß-tubulin III and GFAP, respectively. Moreover, it was observed by Fluoro-Jade-B and caspase-3 immunostaining that apigenin was not neurotoxic and has a neuroprotective effect against inflammatory damage. Additionally, apigenin reduced microglial activation, characterized by inhibition of proliferation (BrdU+ cells) and modulation of microglia morphology (Iba-1 + cells), and decreased the expression of the M1 inflammatory marker CD68. Moreover, as determined by RT-qPCR, inflammatory stimuli induced by IL-1ß increased the mRNA expression of IL-6, IL-1ß, and CCL5, and decreased the mRNA expression of IL-10. Contrary, after treatment with apigenin in inflammatory stimuli (IL-1ß or LPS) there was a modulation of the mRNA expression of inflammatory cytokines, and reduced expression of OX42, IL-6 and gp130. Moreover, apigenin alone and after an inflammatory stimulus with IL-1ß also induced the increase in the expression of brain-derived neurotrophic factor (BDNF), an effect that may be associated with anti-inflammatory and neuroprotective effects. Together these data demonstrate that apigenin presents neuroprotective and anti-inflammatory effects in vitro and might represent an important neuroimmunomodulatory agent for the treatment of neurodegenerative conditions.

RESUMO

Inflammation and oxidative stress are common aspects of most neurodegenerative diseases in the central nervous system. In this context, microglia and astrocytes are central to mediating the balance between neuroprotective and neurodestructive mechanisms. Flavonoids have potent anti-inflammatory and antioxidant properties. Here, we have examined the anti-inflammatory and neuroprotective potential of the flavonoid agathisflavone (FAB), which is derived from the Brazilian plant Poincianella pyramidalis, in in vitro models of neuroinflammation. Cocultures of neurons/glial cells were exposed to lipopolysaccharide (LPS, 1 µg/mL) or interleukin (IL)-1ß (10 ng/mL) for 24 h and treated with FAB (0.1 and 1 µM, 24 h). FAB displayed a significant neuroprotective effect, as measured by nitric oxide (NO) production, Fluoro-Jade B (FJ-B) staining, and immunocytochemistry (ICC) for the neuronal marker ß-tubulin and the cell death marker caspase-3, preserving neuronal soma and increasing neurite outgrowth. FAB significantly decreased the LPS-induced microglial proliferation, identified by ICC for Iba-1/bromodeoxyuridine (BrdU) and CD68 (microglia M1 profile marker). In contrast, FAB had no apparent effect on astrocytes, as determined by ICC for glial fibrillary acidic protein (GFAP). Furthermore, FAB protected against the cytodestructive and proinflammatory effects of IL-1ß, a key cytokine that is released by activated microglia and astrocytes, and ICC showed that combined treatment of FAB with α and ß estrogen receptor antagonists did not affect NF-κB expression. In addition, qPCR analysis demonstrated that FAB decreased the expression of proinflammatory molecules TNF-α, IL-1ß, and connexins CCL5 and CCL2, as well as increased the expression of the regulatory molecule IL-10. Together, these findings indicate that FAB has a significant neuroprotective and anti-inflammatory effect in vitro, which may be considered as an adjuvant for the treatment of neurodegenerative diseases.

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Blood typing techniques have been improved to ensure greater safety for transfusion procedures. Typification for the DEA 1 antigen through flow cytometry should offer more reliability to routine immunohematology in donor and recipient dogs. Currently, the DEA 1 group is starting to be an autosomal dominant allelic system with the DEA 1 negative type and its variations of positivity. The present study investigated the DEA 1 antigen using the techniques of immunochromatography, hemagglutination and flow cytometry. Among the positive animals for the DEA 1 group, typified by flow cytometry, medium intensities of fluorescence were found, which are indicative of weak, moderate and strong antigenicity. This enabled the division of the DEA 1 group into weak positive, moderate positive and strong positive. The blood typing techniques for the DEA 1 group by flow cytometry, agglutination and immunochromatography had positive (Spearman r=0.70) and statistically significant (p>0.0001) correlations.(AU)

As técnicas de tipificação sanguínea vêm sendo aperfeiçoadas para garantir maior segurança aos procedimentos transfusionais. A tipificação para o antígeno AEC 1 com o emprego da citometria de fluxo poderá oferecer mais confiabilidade à rotina da imunohematologia em cães doadores e receptores. Na atualidade, o grupo AEC 1 passou a ser denominado como um sistema alélico autossômico dominante com o tipo AEC 1 negativo e suas variações de positividade. O presente trabalho comparou os resultados de três técnicas utilizadas para a pesquisa do antígeno AEC 1: cromatografia; hemoaglutinação e citometria de fluxo. Dentro dos indivíduos positivos para o grupo AEC 1, tipificados pela citometria de fluxo, foram encontradas intensidades médias de fluorescência indicadoras de antigenicidade fraca, moderada e forte, podendo-se dividir o grupo AEC 1 em positivo fraco, positivo moderado e positivo forte. As técnicas de tipificação sanguínea para o grupo AEC 1 por cromatografia, hemoaglutinação e citometria de fluxo apresentaram correlação positiva (Spearman r=0,70) e estatisticamente significativa (p<0,0001).(AU)

Assuntos

RESUMO

Blood typing techniques have been improved to ensure greater safety for transfusion procedures. Typification for the DEA 1 antigen through flow cytometry should offer more reliability to routine immunohematology in donor and recipient dogs. Currently, the DEA 1 group is starting to be an autosomal dominant allelic system with the DEA 1 negative type and its variations of positivity. The present study investigated the DEA 1 antigen using the techniques of immunochromatography, hemagglutination and flow cytometry. Among the positive animals for the DEA 1 group, typified by flow cytometry, medium intensities of fluorescence were found, which are indicative of weak, moderate and strong antigenicity. This enabled the division of the DEA 1 group into weak positive, moderate positive and strong positive. The blood typing techniques for the DEA 1 group by flow cytometry, agglutination and immunochromatography had positive (Spearman r=0.70) and statistically significant (p>0.0001) correlations.

As técnicas de tipificação sanguínea vêm sendo aperfeiçoadas para garantir maior segurança aos procedimentos transfusionais. A tipificação para o antígeno AEC 1 com o emprego da citometria de fluxo poderá oferecer mais confiabilidade à rotina da imunohematologia em cães doadores e receptores. Na atualidade, o grupo AEC 1 passou a ser denominado como um sistema alélico autossômico dominante com o tipo AEC 1 negativo e suas variações de positividade. O presente trabalho comparou os resultados de três técnicas utilizadas para a pesquisa do antígeno AEC 1: cromatografia; hemoaglutinação e citometria de fluxo. Dentro dos indivíduos positivos para o grupo AEC 1, tipificados pela citometria de fluxo, foram encontradas intensidades médias de fluorescência indicadoras de antigenicidade fraca, moderada e forte, podendo-se dividir o grupo AEC 1 em positivo fraco, positivo moderado e positivo forte. As técnicas de tipificação sanguínea para o grupo AEC 1 por cromatografia, hemoaglutinação e citometria de fluxo apresentaram correlação positiva (Spearman r=0,70) e estatisticamente significativa (p<0,0001).

RESUMO

Blood typing techniques have been improved to ensure greater safety for transfusion procedures. Typification for the DEA 1 antigen through flow cytometry should offer more reliability to routine immunohematology in donor and recipient dogs. Currently, the DEA 1 group is starting to be an autosomal dominant allelic system with the DEA 1 negative type and its variations of positivity. The present study investigated the DEA 1 antigen using the techniques of immunochromatography, hemagglutination and flow cytometry. Among the positive animals for the DEA 1 group, typified by flow cytometry, medium intensities of fluorescence were found, which are indicative of weak, moderate and strong antigenicity. This enabled the division of the DEA 1 group into weak positive, moderate positive and strong positive. The blood typing techniques for the DEA 1 group by flow cytometry, agglutination and immunochromatography had positive (Spearman r=0.70) and statistically significant (p>0.0001) correlations.

As técnicas de tipificação sanguínea vêm sendo aperfeiçoadas para garantir maior segurança aos procedimentos transfusionais. A tipificação para o antígeno AEC 1 com o emprego da citometria de fluxo poderá oferecer mais confiabilidade à rotina da imunohematologia em cães doadores e receptores. Na atualidade, o grupo AEC 1 passou a ser denominado como um sistema alélico autossômico dominante com o tipo AEC 1 negativo e suas variações de positividade. O presente trabalho comparou os resultados de três técnicas utilizadas para a pesquisa do antígeno AEC 1: cromatografia; hemoaglutinação e citometria de fluxo. Dentro dos indivíduos positivos para o grupo AEC 1, tipificados pela citometria de fluxo, foram encontradas intensidades médias de fluorescência indicadoras de antigenicidade fraca, moderada e forte, podendo-se dividir o grupo AEC 1 em positivo fraco, positivo moderado e positivo forte. As técnicas de tipificação sanguínea para o grupo AEC 1 por cromatografia, hemoaglutinação e citometria de fluxo apresentaram correlação positiva (Spearman r=0,70) e estatisticamente significativa (p<0,0001).