Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 47
Filtrar
1.
Environ Res ; 206: 112579, 2022 04 15.
Artigo em Inglês | MEDLINE | ID: mdl-34968437

RESUMO

From a toxicological point of view, particulates and fibres with high solubility in water and/or in biological environments have not been considered in detail and the knowledge to date in this area is very scarce. In this study, the water-soluble natural epsomite fibres from Perticara Mine (Italy) were investigated using SEM-EDS, XRPD, ICP-AES and alpha spectrometry measurements which were combined and integrated to characterise the fibres' morphology, crystal chemistry and mineralogy. The morphological and morphometric results showed that most of the fibres are of inhalable size (Dae 5.09 µm) and can be potentially adsorbed from all parts of the respiratory tract. Chemical analysis reveals significant amounts of toxic elements (As, Co, Fe, Mn, Ni, Sr, Ti, Zn) and surprisingly high contents of radioactive isotopes (210Po and 228Th) in epsomite crystals, making the inhalation of these fibres potentially hazardous to human health. Through this study, we want to focus on soluble minerals, such as epsomite, which can be present in both natural and anthropic environments and have never been considered from the point of view of their potential hazard.


Assuntos
Carvão Mineral , Minerais , Carvão Mineral/análise , Cromatografia Gasosa-Espectrometria de Massas , Humanos , Minerais/análise , Análise Espectral , Água
2.
Philos Trans A Math Phys Eng Sci ; 377(2155): 20190024, 2019 Sep 07.
Artigo em Inglês | MEDLINE | ID: mdl-31424344

RESUMO

Seismic assessment of existing masonry structures requires a numerical model able to both reproduce their nonlinear behaviour and account for the different sources of uncertainties; the latter have to be dealt with since the unavoidable lack of knowledge on the input parameters (material properties, geometry, boundary conditions, etc.) has a relevant effect on the reliability of the seismic response provided by the numerical approaches. The steadily increasing necessity of combining different sources of information/knowledge makes the Bayesian approach an appealing technique, not yet fully investigated for historic masonry constructions. In fact, while the Bayesian paradigm is currently employed to solve inverse problems in several sectors of the structural engineering domain, only a few studies pay attention to its effectiveness for parameter identification on historic masonry structures. This study combines a Bayesian framework with probabilistic structural analyses: starting from the Bayesian finite element model updating by using experimental data it provides the definition of robust seismic fragility curves for non-isolated masonry towers. A comparison between this method and the standard deterministic approach illustrates its benefits. This article is part of the theme issue 'Environmental loading of heritage structures'.

3.
Int J Mol Sci ; 17(12)2016 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-27983697

RESUMO

Neuroplasticity is an "umbrella term" referring to the complex, multifaceted physiological processes that mediate the ongoing structural and functional modifications occurring, at various time- and size-scales, in the ever-changing immature and adult brain, and that represent the basis for fundamental neurocognitive behavioral functions; in addition, maladaptive neuroplasticity plays a role in the pathophysiology of neuropsychiatric dysfunctions. Experiential cues and several endogenous and exogenous factors can regulate neuroplasticity; among these, vitamin E, and in particular α-tocopherol (α-T), the isoform with highest bioactivity, exerts potent effects on many plasticity-related events in both the physiological and pathological brain. In this review, the role of vitamin E/α-T in regulating diverse aspects of neuroplasticity is analyzed and discussed, focusing on the hippocampus, a brain structure that remains highly plastic throughout the lifespan and is involved in cognitive functions. Vitamin E-mediated influences on hippocampal synaptic plasticity and related cognitive behavior, on post-natal development and adult hippocampal neurogenesis, as well as on cellular and molecular disruptions in kainate-induced temporal seizures are described. Besides underscoring the relevance of its antioxidant properties, non-antioxidant functions of vitamin E/α-T, mainly involving regulation of cell signaling molecules and their target proteins, have been highlighted to help interpret the possible mechanisms underlying the effects on neuroplasticity.


Assuntos
Hipocampo/patologia , Hipocampo/fisiopatologia , Plasticidade Neuronal/efeitos dos fármacos , alfa-Tocoferol/farmacologia , Animais , Cognição/efeitos dos fármacos , Hipocampo/efeitos dos fármacos , Hipocampo/crescimento & desenvolvimento , Humanos , Neurogênese/efeitos dos fármacos
4.
Microsc Res Tech ; 87(4): 685-694, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-37982323

RESUMO

Exposure to mineral fibers represents an occupational and environmental hazard since particulate inhalation leads to several health disorders. However, few data are available on the effect of fibers with high solubility like natural epsomite, a water-soluble fiber with an inhalable size that allows it to penetrate biological systems, with regard to the respiratory tract. This study evaluated the natural (fibrous epsomite) and synthetic (Epsom salt) magnesium sulfate pathogenicity. Investigations have been performed through morpho-functional and biochemical analyses, in an in vitro cell model that usually grows as monocytes, but that under appropriate conditions differentiates into macrophages. These latter, known as alveolar macrophages, if referred to lungs, represent the first line of defense against harmful inhaled stimuli. Morphological observations reveal that, if Epsom salt induces osmotic stress on cell culture, natural epsomite fibers lead to cellular alterations including thickening of the nuclear envelope and degenerated mitochondria. Moreover, the insoluble fraction (impurities) internalized by cells induces diffuse damage characterized at the highest dosage and exposure time by secondary necrosis or necrotic cell death features. Biochemical analyses confirm this mineral behavior that involves MAPK pathway activation, resulting in many different cellular responses ranging from proliferation control to cell death. Epsom salt leads to MAPK/ERK activation, a marker predictive of overall survival. Unlike, natural epsomite induces upregulation of MAPK/p38 protein involved in the phosphorylation of downstream targets driving necrotic cell death. These findings demonstrate natural epsomite toxicity on U937 cell culture, making the inhalation of these fibers potentially hazardous for human health. RESEARCH HIGHLIGHTS: Natural epsomite and synthetic Epsom salt effects have been evaluated in U937 cell model. Epsom salt induces an osmotic cellular stress. Natural epsomite fibers lead to cellular damage and can be considered potentially dangerous for human health.


Assuntos
Antineoplásicos , Sulfato de Magnésio , Humanos , Sulfato de Magnésio/farmacologia , Células U937 , Técnicas de Cultura de Células , Macrófagos
5.
Eur J Neurosci ; 37(9): 1394-403, 2013 May.
Artigo em Inglês | MEDLINE | ID: mdl-23373744

RESUMO

Recently, muscle expression of brain-derived neurotrophic factor (BDNF) mRNA and protein under activity control has been reported. BDNF is a neurotrophin known to be involved in axon sprouting in the CNS. Hence, we set out to study the effect of chronic treadmill mid-intensity running on adult rat muscle re-innervation, and to explore the involvement of BDNF and tropomyosin-related kinase (Trk) receptors. After nerve crush, muscle re-innervation was evaluated using intracellular recordings, tension recordings, immunostaining and Western blot analyses. An enhanced muscle multiple innervation was found in running rats that was fully reversed to control values blocking Trk receptors or interrupting the running activity. An increase in muscle multiple innervation was also found in sedentary rats treated with a selective TrkB receptor agonist. The expression of TrkB receptors by intramuscular axons was demonstrated, and increased muscle expression of BDNF was found in running animals. The increase in muscle multiple innervation was consistent with the faster muscle re-innervation that we found in running animals. We conclude that, when regenerating axons contact muscle cells, muscle activity progressively increases modulating BDNF and possibly other growth factors, which in turn, acting via Trk receptors, induce axon sprouting to re-innervate skeletal muscle.


Assuntos
Músculo Esquelético/metabolismo , Regeneração Nervosa , Esforço Físico , Receptor trkB/metabolismo , Animais , Axônios/fisiologia , Fator Neurotrófico Derivado do Encéfalo/farmacologia , Masculino , Músculo Esquelético/inervação , Músculo Esquelético/fisiologia , Compressão Nervosa , Ratos , Ratos Sprague-Dawley , Receptor trkB/agonistas , Receptor trkB/genética
6.
Cell Biol Int ; 37(3): 213-26, 2013 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-23364875

RESUMO

Apoptosis is observed in 'actively' dying cells after the exposure to cell stressors such as ultraviolet light irradiation. Since melatonin has been proposed to act under stressful conditions as cell protection factor, in this study we examined the potential of this molecule when used at pharmacological concentrations to control mitochondrial damage and apoptotic signalling of UVB irradiated U937 human leukaemic cells. Moreover, the effect of melatonin treatment on electrophysiological properties and membrane K(+) currents of irradiated U937 cells was investigated as functional aspects relevant to the anti-apoptotic role of melatonin. The general effect is associated with the restoration of mass, number and membrane potential of mitochondria, with a lower caspase activation and bcl-2 upregulation. In the presence of the caspase inhibitor ZVAD-Fmk, melatonin seems to drive UVB stressed cells to follow the mitochondrial intrinsic pathway, interfering just at the mitochondrial level. Moreover, treatment with melatonin, as well as ZVAD-Fmk, prevented the K(+) current reduction observed late following the UVB insult application, by sparing cells from death; this result also indicates that the decrease of K(+) leakage currents could represent a functional feature of apoptotic process in UV-exposed U937 cells.


Assuntos
Melatonina/farmacologia , Mitocôndrias/fisiologia , Potássio/metabolismo , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , Clorometilcetonas de Aminoácidos , Apoptose , Inibidores de Caspase/farmacologia , Linhagem Celular Tumoral , Membrana Celular/efeitos dos fármacos , Membrana Celular/fisiologia , Membrana Celular/efeitos da radiação , Tamanho Celular , Humanos , Sistema de Sinalização das MAP Quinases , Melatonina/fisiologia , Potencial da Membrana Mitocondrial , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/efeitos da radiação , Tamanho Mitocondrial , Fosforilação , Processamento de Proteína Pós-Traducional , Raios Ultravioleta , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismo
7.
J Invertebr Pathol ; 112(3): 260-6, 2013 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-23262395

RESUMO

Tunicates are chordate invertebrates, closely related to vertebrates, which represent valuable organisms for the study of a variety of biological processes from an evolutionary point of view. As invertebrates, they rely on innate immunity to cope with foreign, potentially pathogenic material. Among tunicates, the compound ascidian Botryllus schlosseri is emerging as a reliable model organism for the study of innate immune responses. However, there is a general lack of knowledge on the signalling pathways activated during immune responses and, in particular, in phagocytosis. In the present work, we carried out a preliminary investigation of the signalling pathways involved in phagocytosis, with particular reference to MAPK activation. We studied in vitro zymosan phagocytosis in the presence of manumycin A, which inhibit the activation of Ras, PD98059, SP600125 and SB202190, inhibitors of Erk, JNK and p38, respectively, parthenolide, N-acetyl-l-cysteine (NAC) and pyrrolidine dithiocarbamate (PDTC), inhibiting NF-kB activation. In addition we carried out immunoblot and immunocytochemistry analysis with the use of anti-pErk1/2, anti-pp38, anti-pJNK, anti-NF-kB (p50) and anti-pan Ras antibodies. Results demonstrate that the recognition of foreign cells triggers a phosphorylation cascade leading to the activation of Ras-like small GTPases, MAPKs and NF-kB and argue in favour of a conservation, also in ascidians, of the main signalling pathways.


Assuntos
Sistema de Sinalização das MAP Quinases , Fagocitose/fisiologia , Urocordados/metabolismo , Animais , MAP Quinases Reguladas por Sinal Extracelular/antagonistas & inibidores , NF-kappa B/antagonistas & inibidores , Fagocitose/efeitos dos fármacos , Fosforilação , Polienos/farmacologia , Alcamidas Poli-Insaturadas/farmacologia , Transdução de Sinais/efeitos dos fármacos , Urocordados/citologia , Urocordados/efeitos dos fármacos , Urocordados/fisiologia , Zimosan/metabolismo
8.
Life (Basel) ; 13(4)2023 Mar 23.
Artigo em Inglês | MEDLINE | ID: mdl-37109392

RESUMO

Environmental disturbances resulting from anthropogenic energy pollution are intensely growing and represent a concern for the marine environment. Benthic organisms are the significant fauna exposed to this kind of pollution; among them, foraminifera are largely used as pollution bioindicators in marine environments, but studies on the effects induced by electrical stimulation are not documented. In the present research, we evaluated the effects of short-term different electric current densities on the viability of benthic foraminiferal species Amphistegina lessonii by checking the pseudopodial activity and defined the threshold electrical density range. After 3 days of treatment, A. lessonii stimulated with a constant current showed pseudopodial activity at a lower electric current density (0.29, 0.86 µA/cm2) up to 24 h. With increasing stimulation time, the percentages of pseudopodial activity decreased. The pseudopodial activity was absent at high current densities (5.71, 8.57 µA/cm2). The viability of A. lessonii exposed to a pulsed current was higher at a low and middle electric current density (from 0.29 to 5.71 µA/cm2) than at a high electric current density (from 11.43 to 20 µA/cm2). Based on these preliminary results, the selected benthic foraminiferal species seems to better stand pulsed currents than constant ones. These first experiments might provide useful information for the definition of the appropriate electrical density threshold to avoid side effects on a part of the benthic community.

9.
Biology (Basel) ; 11(7)2022 Jun 24.
Artigo em Inglês | MEDLINE | ID: mdl-36101341

RESUMO

The evaluation of the effects of pollution (e.g., Hg pollution) is a difficult task and relies mostly on biomonitoring based on bioindicators. The application of biomarkers may represent a complementary or alternative approach in environmental biomonitoring. Mercury is known to pose a significant health hazard due to its ability to cross cellular membranes, bioaccumulate, and biomagnify. In the present research, the effects of short-term (i.e., 24 h) Hg exposure in the symbiont-bearing benthic foraminiferal species Amphistegina lessonii are evaluated using several biomarkers (i.e., proteins and enzymes). Mercury leads to significant changes in the biochemistry of cells. Its effects are mainly associated with oxidative stress (i.e., production of reactive oxygen species: ROS), depletion of glutathione (GSH), and alteration of protein synthesis. Specifically, our findings reveal that exposure to Hg leads to the consumption of GSH by GPx and GST for the scavenging of ROS and the activation of antioxidant-related enzymes, including SOD and GSH-enzymes (GST, GSR, GPx, and Se-GPx), that are directly related to a defense mechanism against ROS. The Hg exposure also activates the MAPK (e.g., p-p38) and HSP (e.g., HSP 70) pathways. The observed biochemical alterations associated with Hg exposure may represent effective and reliable proxies (i.e., biomarkers) for the evaluation of stress in A. lessonii and lead to a possible application for the detection of early warning signs of environmental stress in biomonitoring.

10.
Chemosphere ; 291(Pt 3): 133067, 2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-34838598

RESUMO

This study explored the morphological, mineralogical, and physico-chemical features of carcinogenic erionite and other possibly hazardous zeolites, such as mesolite and thomsonite, while also investigating the interacting capability of the mineral surface at the liquid/solid interface. Extremely fibrous erionite is K+ and Ca2+-rich and shows the highest Si/Al ratio (3.38) and specific surface area (8.14 m2/g). Fibrous mesolite is Na+ and Ca2+-rich and displays both a lower Si/Al ratio (1.56) and a smaller specific surface area (1.56 m2/g). The thomsonite composition shows the lowest values of Si/Al ratio (1.23) and specific surface area (0.38 m2/g). Electron paramagnetic resonance data from selected spin probes reveal that erionite has a homogeneous site distribution and interacts well with all spin probes. The surfaces of mesolite and thomsonite are less homogeneous and closer polar sites were found through consequent interaction with the probes. The mesolite surface can also clearly interact but with a lower strength and may represent a potential health hazard for humans, though with a lower degree if compared to erionite. The thomsonite surface is not inert and interacts with the probes with a low-grade capability. We can expect small fragments of thomsonite to interact with the biological environment, though with a low-grade intensity.


Assuntos
Zeolitas , Carcinógenos , Espectroscopia de Ressonância de Spin Eletrônica , Humanos
11.
FASEB J ; 24(10): 3603-24, 2010 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-20534884

RESUMO

Besides its well-known regulatory role on circadian rhythm, the pineal gland hormone melatonin has other biological functions and a distinct metabolism in various cell types and peripheral tissues. In different tissues and organs, melatonin has been described to act as a paracrine and also as an intracrine and autocrine agent with overall homeostatic functions and pleiotropic effects that include cell protection and prosurvival factor. These latter effects, documented in a number of in vitro and in vivo studies, are sustained through both receptor-dependent and -independent mechanisms that control detoxification and stress response genes, thus conferring protection against a number of xenobiotics and endobiotics produced by acute and chronic noxious stimuli. Redox-sensitive components are included in the cell protection signaling of melatonin and in the resulting transcriptional response that involves the control of NF-κB, AP-1, and Nrf2. By these pathways, melatonin stimulates the expression of antioxidant and detoxification genes, acting in turn as a glutathione system enhancer. A further and converging mechanism of cell protection by this indoleamine described in different models seems to lie in the control of damage and signaling function of mitochondria that involves decreased production of reactive oxygen species and activation of the antiapoptotic and redox-sensitive element Bcl2. Recent evidence suggests that upstream components in this mitochondrial route include the calmodulin pathway with its central role in melatonin signaling and the survival-promoting component of MAPKs, ERK1/2. In this review article, we will discuss these and other molecular aspects of melatonin signaling relevant to cell protection and survival mechanisms.


Assuntos
Citoproteção , Melatonina/metabolismo , Transdução de Sinais , Glutationa/metabolismo , Humanos , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Oxirredução , Fatores de Transcrição/metabolismo
12.
Life (Basel) ; 11(5)2021 May 05.
Artigo em Inglês | MEDLINE | ID: mdl-34063137

RESUMO

Proteins are essential to life, and the evaluation of their content, identification, and modification represents a fundamental assay in biochemistry research. Different analytical techniques and protocols have been specifically designed but have rarely been compared. Here, we test and compare a variety of methodologies and treatments for the quantification of proteins in Amphistegina lessonii, a larger symbiont-bearing benthic foraminiferal species. These analyses specifically include (a) lysis buffer (homemade vs. RIPA), (b) protein assays (Lowry, BCA, and Bradford), (c) ultrasonic bath treatment, and (d) protein staining (silver staining vs. Coomassie blue). On the basis of the comparative outcome, we suggest using the homemade lysis buffer, Lowry or BCA assays, ultrasonic bath treatment, and silver stain to maximize the extraction and characterization of protein for A. lessonii. This protocol might be suitable and extended to other benthic foraminiferal species, including the smaller ones.

13.
Antioxidants (Basel) ; 10(2)2021 Jan 25.
Artigo em Inglês | MEDLINE | ID: mdl-33503988

RESUMO

The metabolism of α-tocopherol (α-TOH, vitamin E) shows marked interindividual variability, which may influence the response to nutritional and therapeutic interventions with this vitamin. Recently, new metabolomics protocols have fostered the possibility to explore such variability for the different metabolites of α-TOH so far identified in human blood, i.e., the "vitamin E metabolome", some of which have been reported to promote important biological functions. Such advances prompt the definition of reference values and degree of interindividual variability for these metabolites at different levels of α-TOH intake. To this end, a one-week oral administration protocol with 800 U RRR-α-TOH/day was performed in 17 healthy volunteers, and α-TOH metabolites were measured in plasma before and at the end of the intervention utilizing a recently validated LC-MS/MS procedure; the expression of two target genes of α-TOH with possible a role in the metabolism and function of this vitamin, namely pregnane X receptor (PXR) and the isoform 4F2 of cytochrome P450 (CYP4F2) was assessed by immunoblot in peripheral blood leukocytes. The levels of enzymatic metabolites showed marked interindividual variability that characteristically increased upon supplementation. With the exception of α-CEHC (carboxy-ethyl-hydroxychroman) and the long-chain metabolites M1 and α-13'OH, such variability was found to interfere with the possibility to utilize them as sensitive indicators of α-TOH intake. On the contrary, the free radical-derived metabolite α-tocopheryl quinone significantly correlated with the post-supplementation levels of α-TOH. The supplementation stimulated PXR, but not CYP4F2, expression of leucocytes, and significant correlations were observed between the baseline levels of α-TOH and both the baseline and post-supplementation levels of PXR. These findings provide original analytical and molecular information regarding the human metabolism of α-TOH and its intrinsic variability, which is worth considering in future nutrigenomics and interventions studies.

14.
J Invertebr Pathol ; 105(1): 49-55, 2010 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-20493193

RESUMO

In mussel (Mytilus sp.) hemocytes, differential functional responses to injection with different types of live and heat-killed Vibrio species have been recently demonstrated. In this work, responses of Mytilus hemocytes to heat-killed Vibrio splendidus LGP32 and the mechanisms involved were investigated in vitro and the results were compared with those obtained with Vibrio anguillarum (ATCC 19264). Adhesion of hemocytes after incubation with bacteria was evaluated by flow cytometry: both total hemocyte counts (THC) and percentage of hemocyte sub-populations were determined in non-adherent cells. Functional parameters such as lysosomal membrane stability, lysozyme release, extracellular ROS production and NO production were evaluated, as well as the phosphorylation state of the stress-activated p38 MAPK and PKC. Neither Vibrio affected total hemocyte adhesion, while both induced similar lysosomal destabilization and NO production. However, V. splendidus decreased adhesion of large granulocytes, induced rapid and persistent lysozyme release and stimulated extracellular ROS production: these effects were associated with persistent activation of p38 MAPK and PKC. In contrast, V. anguillarum decreased adhesion of large semigranular hemocytes and increased that of hyalinocytes, had no effect on the extracellular ROS production, and induced significantly lower lysozyme release and phosphorylation of p-38 MAPK and PKC than V. splendidus. These data reinforced the existence of specific interactions between mussel hemocytes and V. splendidus LGP32 and suggest that this Vibrio strain affects bivalve hemocytes through disregulation of immune signaling. The results support the hypothesis that responses of bivalve hemocytes to different bacterial stimuli may depend not only on the nature of the stimulus, but also on the cell subtype, thus leading to differential activation of signaling components.


Assuntos
Hemócitos/metabolismo , Mytilus/imunologia , Mytilus/microbiologia , Proteína Quinase C/metabolismo , Vibrio/classificação , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismo , Animais , Adesão Celular/fisiologia , Hemócitos/citologia , Muramidase/metabolismo , Mytilus/metabolismo , Óxido Nítrico/metabolismo , Fosforilação/fisiologia , Espécies Reativas de Oxigênio/metabolismo , Transdução de Sinais/fisiologia , Especificidade da Espécie , Vibrio/patogenicidade
15.
Chirality ; 21(5): 519-24, 2009 May.
Artigo em Inglês | MEDLINE | ID: mdl-18655162

RESUMO

Vitamin E derivatives bearing a carboxylic group have recently gained great attention because of their antitumoral properties. Garcinoic acid (trans-13'-carboxy-delta-tocotrienol) is a vitamin E analog extracted from Garcinia Kola seeds in which the carboxylic group is at the end of the aliphatic side chain and reported to be a racemate based on the optical rotation measurements. However, CD determination of a sample of the acid analyzed by us gave a positive peak at 208 nm, indicating that it is not a racemate. To assess the enantiomeric composition of garcinoic acid, it was thus transformed to alpha-tocopherol and analyzed by chiral HPLC on column OD-H. On the basis of the elution order of alpha-tocopherol stereoisomers, the garcinoic acid sample resulted to be enantiopure with R configuration at carbon 2 of the chroman ring. Moreover, in a preliminary test, the acid and some of its derivatives showed a marked antiproliferative effect on glioma C6 cancer cells.


Assuntos
Anticarcinógenos/farmacologia , Antioxidantes/farmacologia , Benzopiranos/farmacologia , Garcinia kola/química , Tocoferóis/química , Antioxidantes/química , Apoptose/efeitos dos fármacos , Benzopiranos/química , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Cromatografia Líquida de Alta Pressão , Ensaios de Seleção de Medicamentos Antitumorais , Humanos , Estrutura Molecular , Extratos Vegetais/farmacologia , Sementes/química , Estereoisomerismo , Tocoferóis/farmacologia , Vitamina E/análogos & derivados , Vitamina E/química , alfa-Tocoferol/química , alfa-Tocoferol/farmacologia
16.
Biochim Biophys Acta Mol Basis Dis ; 1865(6): 1098-1112, 2019 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-30703511

RESUMO

Glutamate-mediated excitotoxicity, neuroinflammation, and oxidative stress are common underlying events in neurodegeneration. This pathogenic "triad" characterizes the neurobiology of epilepsy, leading to seizure-induced cell death, increased susceptibility to neuronal synchronization and network alterations. Along with other maladaptive changes, these events pave the way to spontaneous recurrent seizures and progressive degeneration of the interested brain areas. In vivo models of epilepsy are available to explore such epileptogenic mechanisms, also assessing the efficacy of chemoprevention and therapy strategies at the pre-clinical level. The kainic acid model of pharmacological excitotoxicity and epileptogenesis is one of the most investigated mimicking the chronicization profile of temporal lobe epilepsy in humans. Its pathogenic cues include inflammatory and neuronal death pathway activation, mitochondrial disturbances and lipid peroxidation of several regions of the brain, the most vulnerable being the hippocampus. The importance of neuroinflammation and lipid peroxidation as underlying molecular events of brain damage was demonstrated in this model by the possibility to counteract the related maladaptive morphological and functional changes of this organ with vitamin E, the main fat-soluble cellular antioxidant and "conditional" co-factor of enzymatic pathways involved in polyunsaturated lipid metabolism and inflammatory signaling. The present review paper provides an overview of the literature supporting the potential for a timely intervention with vitamin E therapy in clinical management of seizures and epileptogenic processes associated with excitotoxicity, neuroinflammation and lipid peroxidation, i.e. the pathogenic "triad".


Assuntos
Encéfalo/fisiopatologia , Epilepsia/fisiopatologia , Inflamação/fisiopatologia , Doenças Neurodegenerativas/fisiopatologia , Estresse Oxidativo/fisiologia , Animais , Antioxidantes/administração & dosagem , Encéfalo/efeitos dos fármacos , Encéfalo/metabolismo , Epilepsia/tratamento farmacológico , Epilepsia/metabolismo , Humanos , Inflamação/tratamento farmacológico , Inflamação/metabolismo , Ácido Caínico/metabolismo , Doenças Neurodegenerativas/tratamento farmacológico , Doenças Neurodegenerativas/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Vitamina E/administração & dosagem
17.
Environ Int ; 34(8): 1114-9, 2008 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-18486973

RESUMO

The potential for human and ecological toxicity associated with nanomaterials is a growing area of investigation. In mammalian cells, nanoparticles have been shown to induce inflammation and oxidative stress, and changes in cell signalling and gene expression. As the nanotechnology industries increase production, nanoscale products and by products will enter the aquatic environment, posing a possible threat to aquatic organisms. In particular, filter-feeding organisms may represent a unique target group for nanoparticle toxicology. In this work, the effects of commercial nanosized carbon black (NCB) on the immune cells, the hemocytes, of the bivalve mollusc Mytilus, and the possible mechanisms involved were investigated. The results demonstrate that NCB (1, 5, and 10 microg/ml), did not induce significant lysosomal membrane destabilization, as evaluated by the NR retention time assay. A concentration-dependent uptake of NCB by hemocytes was observed and it was associated by a rapid increase in extracellular lysozyme release, extracellular oxyradical production, and nitric oxide (NO) release. Moreover, at the highest concentration tested, NCB induced significant changes in mitochondrial parameters (decrease mitochondrial mass/number and membrane potential), as evaluated by flow cytometry. The effects of NCB were mediated by rapid activation of the stress-activated MAPKs (Mitogen Activated Protein Kinases) p38 and JNKs, that play a key role in immune and inflammatory responses. The results demonstrate that in mussel hemocytes like in mammalian cells NCB exposure can induce inflammatory processes, and indicate that bivalve immunocytes can represent a suitable model for investigating the effects and modes of action of nanoparticles in the cells of aquatic invertebrates.


Assuntos
Bivalves/efeitos dos fármacos , Hemócitos/efeitos dos fármacos , Nanopartículas , Fuligem/toxicidade , Poluentes Químicos da Água/toxicidade , Animais , Western Blotting , Eletroforese em Gel de Poliacrilamida , Citometria de Fluxo
18.
Oxid Med Cell Longev ; 2018: 4968321, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29849898

RESUMO

Oxidative stress can alter the expression level of many microRNAs (miRNAs), but how these changes are integrated and related to oxidative stress responses is poorly understood. In this article, we addressed this question by using in silico tools. We reviewed the literature for miRNAs whose expression is altered upon oxidative stress damage and used them in combination with various databases and software to predict common gene targets of oxidative stress-modulated miRNAs and affected pathways. Furthermore, we identified miRNAs that simultaneously target the predicted oxidative stress-modulated miRNA gene targets. This generated a list of novel candidate miRNAs potentially involved in oxidative stress responses. By literature search and grouping of pathways and cellular responses, we could classify these candidate miRNAs and their targets into a larger scheme related to oxidative stress responses. To further exemplify the potential of our approach in free radical research, we used our explorative tools in combination with ingenuity pathway analysis to successfully identify new candidate miRNAs involved in the ubiquitination process, a master regulator of cellular responses to oxidative stress and proteostasis. Lastly, we demonstrate that our approach may also be useful to identify novel candidate connections between oxidative stress-related miRNAs and autophagy. In summary, our results indicate novel and important aspects with regard to the integrated biological roles of oxidative stress-modulated miRNAs and demonstrate how this type of in silico approach can be useful as a starting point to generate hypotheses and guide further research on the interrelation between miRNA-based gene regulation, oxidative stress signaling pathways, and autophagy.


Assuntos
MicroRNAs/metabolismo , Estresse Oxidativo/genética , Autofagia , Transdução de Sinais
19.
Mol Neurobiol ; 55(10): 7822-7838, 2018 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-29468563

RESUMO

Seizure-triggered maladaptive neural plasticity and neuroinflammation occur during the latent period as a key underlying event in epilepsy chronicization. Previously, we showed that α-tocopherol (α-T) reduces hippocampal neuroglial activation and neurodegeneration in the rat model of kainic acid (KA)-induced status epilepticus (SE). These findings allowed us to postulate an antiepileptogenic potential for α-T in hippocampal excitotoxicity, in line with clinical evidence showing that α-T improves seizure control in drug-resistant patients. To explore neurobiological correlates of the α-T antiepileptogenic role, rats were injected with such vitamin during the latent period starting right after KA-induced SE, and the effects on circuitry excitability, neuroinflammation, neuronal death, and microRNA (miRNA) expression were investigated in the hippocampus. Results show that in α-T-treated epileptic rats, (1) the number of population spikes elicited by pyramidal neurons, as well as the latency to the onset of epileptiform-like network activity recover to control levels; (2) neuronal death is almost prevented; (3) down-regulation of claudin, a blood-brain barrier protein, is fully reversed; (4) neuroinflammation processes are quenched (as indicated by the decrease of TNF-α, IL-1ß, GFAP, IBA-1, and increase of IL-6); (5) miR-146a, miR-124, and miR-126 expression is coherently modulated in hippocampus and serum by α-T. These findings support the potential of a timely intervention with α-T in clinical management of SE to reduce epileptogenesis, thus preventing chronic epilepsy development. In addition, we suggest that the analysis of miRNA levels in serum could provide clinicians with a tool to evaluate disease evolution and the efficacy of α-T therapy in SE.


Assuntos
Regulação da Expressão Gênica/efeitos dos fármacos , MicroRNAs/genética , Convulsões/induzido quimicamente , Convulsões/genética , Estado Epiléptico/tratamento farmacológico , Estado Epiléptico/genética , alfa-Tocoferol/uso terapêutico , Animais , Barreira Hematoencefálica/efeitos dos fármacos , Barreira Hematoencefálica/patologia , Modelos Animais de Doenças , Inflamação/patologia , Ácido Caínico , Masculino , MicroRNAs/metabolismo , Degeneração Neural/tratamento farmacológico , Degeneração Neural/patologia , Oócitos/efeitos dos fármacos , Oócitos/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Ratos Sprague-Dawley , Receptores de GABA/metabolismo , Convulsões/fisiopatologia , Estado Epiléptico/fisiopatologia , Xenopus , Ácido alfa-Amino-3-hidroxi-5-metil-4-isoxazol Propiônico/metabolismo , alfa-Tocoferol/farmacologia
20.
Aquat Toxicol ; 81(1): 36-44, 2007 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-17126923

RESUMO

Endocrine disrupting compounds (EDCs) are almost ubiquitous in the aquatic environment. In the marine bivalve Mytilus the natural estrogen 17beta-estradiol (E2) and different EDCs have been recently demonstrated to affect the function of the immune cells, the hemocytes. The effects were Tamoxifen-sensitive and were mediated by rapid modulation of kinase-mediated transduction pathways. In this work we compared the in vitro effects of individual estrogenic chemicals (E2, EE: 17alpha-ethynyl estradiol; MES: mestranol; NP: nonylphenol; NP1EC: nonylphenol monoethoxylate carboxylate; BPA: bisphenol A; BP: benzophenone) on hemocyte parameters: lysosomal membrane stability (LMS), phagocytosis, lysozyme release. LMS was the most sensitive effect parameter, showing a decreasing trend at increasing concentrations of estrogens. EC50 values obtained from LMS data were utilized to calculate the estradiol equivalency factor (EEF) for each compound; these EEFs allowed for an estimation of the estrogenic potential of a synthetic mixture with a composition very similar to that previously found in waters of the Venice lagoon. Concentrated mixtures significantly affected hemocyte parameters in vitro and the effects were prevented by Tamoxifen. Significant effects of the mixture were also observed in vivo, at longer exposure times and at concentrations comparable with environmental exposure levels. The results indicate that Mytilus immune parameters can be suitably utilized to evaluate the estrogenic potential of environmental samples.


Assuntos
Disruptores Endócrinos/toxicidade , Estrogênios/toxicidade , Hemócitos/efeitos dos fármacos , Mytilus/efeitos dos fármacos , Poluentes Químicos da Água/toxicidade , Animais , Exposição Ambiental , Monitoramento Ambiental/métodos , Estradiol/toxicidade , Etinilestradiol/toxicidade , Hemócitos/imunologia , Lisossomos/efeitos dos fármacos , Mestranol/toxicidade , Mytilus/imunologia , Fagocitose/efeitos dos fármacos , Tamoxifeno/farmacologia , Fatores de Tempo
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA