19 results on '"Malva, João Oliveira"'
Search Results
2. Histamine in the Neural and Cancer Stem Cell Niches
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Eiriz, Maria Francisca, Malva, João Oliveira, Agasse, Fabienne, Bernardino, Liliana, Hayat, M. A., Series editor, and Hayat, M.A., editor
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- 2014
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3. Silencing of P2X7R by RNA interference in the hippocampus can attenuate morphological and behavioral impact of pilocarpine-induced epilepsy
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Amorim, Rebeca Padrão, Araújo, Michelle Gasparetti Leão, Valero, Jorge, Lopes-Cendes, Iscia, Pascoal, Vinicius Davila Bitencourt, Malva, João Oliveira, and da Silva Fernandes, Maria José
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- 2017
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4. Histamine in the Neural and Cancer Stem Cell Niches
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Eiriz, Maria Francisca, primary, Malva, João Oliveira, additional, Agasse, Fabienne, additional, and Bernardino, Liliana, additional
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- 2013
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5. Additional file 2 of Unhealthy lifestyles, environment, well-being and health capability in rural neighbourhoods: a community-based cross-sectional study
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Azul, Anabela Marisa, Almendra, Ricardo, Quatorze, Marta, Loureiro, Adriana, Reis, Flávio, Tavares, Rui, Mota-Pinto, Anabela, Cunha, António, Rama, Luís, Malva, João Oliveira, Santana, Paula, and Ramalho-Santos, João
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ComputerApplications_GENERAL ,ComputingMethodologies_GENERAL - Abstract
Additional file 2: Table S2. Characterization of the community environment needs by neighbourhoods’ type and self-assessment of neighbourhood’ satisfaction.
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- 2021
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6. Additional file 1 of Unhealthy lifestyles, environment, well-being and health capability in rural neighbourhoods: a community-based cross-sectional study
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Azul, Anabela Marisa, Almendra, Ricardo, Quatorze, Marta, Loureiro, Adriana, Reis, Flávio, Tavares, Rui, Mota-Pinto, Anabela, Cunha, António, Rama, Luís, Malva, João Oliveira, Santana, Paula, and Ramalho-Santos, João
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ComputingMethodologies_GENERAL - Abstract
Additional file 1: Table S1. Evidence-based data by neighbourhoods’ type.
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- 2021
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7. Unhealthy lifestyles, environment, well-being and health capability in rural neighbourhoods:a community-based cross-sectional study
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Azul, Anabela Marisa, Almendra, Ricardo, Quatorze, Marta, Loureiro, Adriana, Reis, Flávio, Tavares, Rui, Mota-Pinto, Anabela, Cunha, António, Rama, Luís, Malva, João Oliveira, Santana, Paula, Ramalho-Santos, João, Sandholdt, Catharina Thiel, Kristiansen, Maria, Azul, Anabela Marisa, Almendra, Ricardo, Quatorze, Marta, Loureiro, Adriana, Reis, Flávio, Tavares, Rui, Mota-Pinto, Anabela, Cunha, António, Rama, Luís, Malva, João Oliveira, Santana, Paula, Ramalho-Santos, João, Sandholdt, Catharina Thiel, and Kristiansen, Maria
- Abstract
BACKGROUND: Non-communicable diseases are a leading cause of health loss worldwide, in part due to unhealthy lifestyles. Metabolic-based diseases are rising with an unhealthy body-mass index (BMI) in rural areas as the main risk factor in adults, which may be amplified by wider determinants of health. Changes in rural environments reflect the need of better understanding the factors affecting the self-ability for making balanced decisions. We assessed whether unhealthy lifestyles and environment in rural neighbourhoods are reflected into metabolic risks and health capability.METHODS: We conducted a community-based cross-sectional study in 15 Portuguese rural neighbourhoods to describe individuals' health functioning condition and to characterize the community environment. We followed a qualitatively driven mixed-method design to gather information about evidence-based data, lifestyles and neighbourhood satisfaction (incorporated in eVida technology), within a random sample of 270 individuals, and in-depth interviews to 107 individuals, to uncover whether environment influence the ability for improving or pursuing heath and well-being.RESULTS: Men showed to have a 75% higher probability of being overweight than women (p-value = 0.0954); and the reporting of health loss risks was higher in women (RR: 1.48; p-value = 0.122), individuals with larger waist circumference (RR: 2.21; IC: 1.19; 4.27), overweight and obesity (RR: 1.38; p-value = 0.293) and aged over 75 years (RR: 1.78; p-value = 0.235; when compared with participants under 40 years old). Metabolic risks were more associated to BMI and physical activity than diet (or sleeping habits). Overall, metabolic risk linked to BMI was higher in small villages than in municipalities. Seven dimensions, economic development, built (and natural) environment, social network, health care, demography, active lifestyles, and mobility, reflected the self-perceptions in place affecting the individual ability to
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- 2021
8. (Un)Healthy Lifestyles, Environment, Well-being and Health Capability in Rural Neighbourhoods: A Community-based Cross-sectional Study
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Azul, Anabela Marisa, Almendra, Ricardo, Quatorze, Marta, Loureiro, Adriana, Reis, Flávio, Tavares, Rui, Mota-Pinto, Anabela, Cunha, António, Rama, Luís, Malva, João Oliveira, Santana, Paula, Ramalho-Santos, João, Sandholdt, Catharina Thiel, and Kristiansen, Maria
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Adult ,Male ,Rural Population ,Built environment ,medicine.medical_specialty ,Participatory community-based research ,Áreas rurais ,Overweight ,Rural areas ,Body Mass Index ,Environmental health ,Health care ,Humans ,Medicine ,Social determinants of health ,Non-communicable diseases ,Life Style ,Socioeconomic status ,Neighbourhood (mathematics) ,Natural environment ,Aged ,Doenças Não-comunicáveis ,business.industry ,Public health ,Estilos de vida saudáveis ,Public Health, Environmental and Occupational Health ,Perda de saúde ,Health loss ,Cross-Sectional Studies ,Health capability ,Female ,Ambiente natural ,Qualitative driven mixed-methods ,Waist Circumference ,medicine.symptom ,Rural area ,Public aspects of medicine ,RA1-1270 ,business ,Healthy lifestyles ,Research Article - Abstract
Background Non-communicable diseases are a leading cause of health loss worldwide, in part due to unhealthy lifestyles. Metabolic-based diseases are rising with an unhealthy body-mass index (BMI) in rural areas as the main risk factor in adults, which may be amplified by wider determinants of health. Changes in rural environments reflect the need of better understanding the factors affecting the self-ability for making balanced decisions. We assessed whether unhealthy lifestyles and environment in rural neighbourhoods are reflected into metabolic risks and health capability. Methods We conducted a community-based cross-sectional study in 15 Portuguese rural neighbourhoods to describe individuals’ health functioning condition and to characterize the community environment. We followed a qualitatively driven mixed-method design to gather information about evidence-based data, lifestyles and neighbourhood satisfaction (incorporated in eVida technology), within a random sample of 270 individuals, and in-depth interviews to 107 individuals, to uncover whether environment influence the ability for improving or pursuing heath and well-being. Results Men showed to have a 75% higher probability of being overweight than women (p-value = 0.0954); and the reporting of health loss risks was higher in women (RR: 1.48; p-value = 0.122), individuals with larger waist circumference (RR: 2.21; IC: 1.19; 4.27), overweight and obesity (RR: 1.38; p-value = 0.293) and aged over 75 years (RR: 1.78; p-value = 0.235; when compared with participants under 40 years old). Metabolic risks were more associated to BMI and physical activity than diet (or sleeping habits). Overall, metabolic risk linked to BMI was higher in small villages than in municipalities. Seven dimensions, economic development, built (and natural) environment, social network, health care, demography, active lifestyles, and mobility, reflected the self-perceptions in place affecting the individual ability to make healthy choices. Qualitative data exposed asymmetries in surrounding environments among neighbourhoods and uncovered the natural environment and natural resources specifies as the main value of rural well-being. Conclusions Metabolic risk factors reflect unhealthy lifestyles and can be associated with environment contextual-dependent circumstances. People-centred approaches highlight wider socioeconomic and (natural) environmental determinants reflecting health needs, health expectations and health capability. Our community-based program and cross-disciplinary research provides insights that may improve health-promoting changes in rural neighbourhoods.
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- 2020
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9. Methylmercury Impact on Adult Neurogenesis: Is the Worst Yet to Come From Recent Brazilian Environmental Disasters?
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Raposo, Ramon da Silva, primary, Pinto, Daniel Vieira, additional, Moreira, Ricardo, additional, Dias, Ronaldo Pereira, additional, Fontes Ribeiro, Carlos Alberto, additional, Oriá, Reinaldo Barreto, additional, and Malva, João Oliveira, additional
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- 2020
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10. (Un)Healthy Lifestyles, Environment, Well-being and Health Capability in Rural Neighbourhoods: A Community-based Cross-sectional Study
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Azul, Anabela Marisa, primary, Almendra, Ricardo, additional, Quatorze, Marta, additional, Loureiro, Adriana, additional, Reis, Flávio, additional, Tavares, Rui, additional, Mota-Pinto, Anabela, additional, Cunha, António, additional, Rama, Luís, additional, Malva, João Oliveira, additional, Santana, Paula, additional, and Ramalho-Santos, João, additional
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- 2020
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11. Neurotoxicity Induced by Antiepileptic Drugs in Cultured Hippocampal Neurons: A Comparative Study between Carbamazepine, Oxcarbazepine, and Two New Putative Antiepileptic Drugs, BIA 2-024 and BIA 2-093
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Araújo, Inês M., Ambrósio, António Francisco, Leal, Ermelindo C., Verdasca, Maria João, Malva, João Oliveira, Soares-da-Silva, Patrício, Carvalho, Arsélio Pato, and Carvalho, Caetana Monteiro
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- 2004
12. Unhealthy lifestyles, environment, well-being and health capability in rural neighbourhoods: a community-based cross-sectional study.
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Azul, Anabela Marisa, Almendra, Ricardo, Quatorze, Marta, Loureiro, Adriana, Reis, Flávio, Tavares, Rui, Mota-Pinto, Anabela, Cunha, António, Rama, Luís, Malva, João Oliveira, Santana, Paula, Ramalho-Santos, João, HeaLIQs4Cities consortium, Pardal, André, Peixoto, Eugénia, Guardado, Diana, Zwaving, Marieke, De La Blanca, Eduardo Briones Pérez, van der Heijden, Roel A., and Van't Jagt, Ruth Koops
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LIFESTYLES ,NEIGHBORHOODS ,NON-communicable diseases ,BUILT environment ,RURAL geography - Abstract
Background: Non-communicable diseases are a leading cause of health loss worldwide, in part due to unhealthy lifestyles. Metabolic-based diseases are rising with an unhealthy body-mass index (BMI) in rural areas as the main risk factor in adults, which may be amplified by wider determinants of health. Changes in rural environments reflect the need of better understanding the factors affecting the self-ability for making balanced decisions. We assessed whether unhealthy lifestyles and environment in rural neighbourhoods are reflected into metabolic risks and health capability.Methods: We conducted a community-based cross-sectional study in 15 Portuguese rural neighbourhoods to describe individuals' health functioning condition and to characterize the community environment. We followed a qualitatively driven mixed-method design to gather information about evidence-based data, lifestyles and neighbourhood satisfaction (incorporated in eVida technology), within a random sample of 270 individuals, and in-depth interviews to 107 individuals, to uncover whether environment influence the ability for improving or pursuing heath and well-being.Results: Men showed to have a 75% higher probability of being overweight than women (p-value = 0.0954); and the reporting of health loss risks was higher in women (RR: 1.48; p-value = 0.122), individuals with larger waist circumference (RR: 2.21; IC: 1.19; 4.27), overweight and obesity (RR: 1.38; p-value = 0.293) and aged over 75 years (RR: 1.78; p-value = 0.235; when compared with participants under 40 years old). Metabolic risks were more associated to BMI and physical activity than diet (or sleeping habits). Overall, metabolic risk linked to BMI was higher in small villages than in municipalities. Seven dimensions, economic development, built (and natural) environment, social network, health care, demography, active lifestyles, and mobility, reflected the self-perceptions in place affecting the individual ability to make healthy choices. Qualitative data exposed asymmetries in surrounding environments among neighbourhoods and uncovered the natural environment and natural resources specifies as the main value of rural well-being.Conclusions: Metabolic risk factors reflect unhealthy lifestyles and can be associated with environment contextual-dependent circumstances. People-centred approaches highlight wider socioeconomic and (natural) environmental determinants reflecting health needs, health expectations and health capability. Our community-based program and cross-disciplinary research provides insights that may improve health-promoting changes in rural neighbourhoods. [ABSTRACT FROM AUTHOR]- Published
- 2021
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13. Impact of Neuroinflammation on Hippocampal Neurogenesis: Relevance to Aging and Alzheimer’s Disease
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Valero, Jorge, primary, Bernardino, Liliana, additional, Cardoso, Filipa Lourenço, additional, Silva, Ana Paula, additional, Fontes-Ribeiro, Carlos, additional, Ambrósio, António Francisco, additional, and Malva, João Oliveira, additional
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- 2017
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14. Cobalt staining of hippocampal neurons mediated by non-desensitizing activation of AMPA but not kainate receptors
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Malva, João Oliveira, primary, Vieira, Ana P., additional, Ambrósio, António F., additional, and Oliveira, Catarina R., additional
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- 2003
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15. New insights into the role of histamine in subventricular zone-olfactory bulb neurogenesis.
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Eiriz, Maria Francisca, Valero, Jorge, Malva, João Oliveira, and Bernardino, Liliana
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HISTAMINE ,OLFACTORY bulb ,DEVELOPMENTAL neurobiology ,NEURAL stem cells ,CEREBROSPINAL fluid ,NEUROTRANSMITTERS - Abstract
The subventricular zone (SVZ) contains neural stem cells (NSCs) that generate new neurons throughout life. Many brain diseases stimulate NSCs proliferation, neuronal differentiation and homing of these newborns cells into damaged regions. However, complete cell replacement has never been fully achieved. Hence, the identification of proneurogenic factors crucial for stem cell-based therapies will have an impact in brain repair. Histamine, a neurotransmitter and immune mediator, has been recently described to modulate proliferation and commitment of NSCs. Histamine levels are increased in the brain parenchyma and at the cerebrospinal fluid (CSF) upon inflammation and brain injury, thus being able to modulate neurogenesis. Herein, we add new data showing that in vivo administration of histamine in the lateral ventricles has a potent proneurogenic effect, increasing the production of new neuroblasts in the SVZ that ultimately reach the olfactory bulb (OB). This report emphasizes the multidimensional effects of histamine in the modulation of NSCs dynamics and sheds light into the promising therapeutic role of histamine for brain regenerative medicine. [ABSTRACT FROM AUTHOR]
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- 2014
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16. Inhibiting COMT in a mouse model of Parkinson's disease: a trial of Tolcapone in VMAT2-deficient mice
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Moreira, Carlos Filipe Gonçalves, Noain, Daniela, and Malva, João Oliveira
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Ciências da Saúde ,Engenharia biomédica ,Doença de Parkinson ,Neurofarmacologia - Abstract
Na doença de Parkinson, a perda progressiva de neurónios produtores de dopamina da substantia nigra pars compacta conduz a desequilíbrios neuroquímicos da gânglia basal e, consequentemente, ao surgimento de sintomas como bradicinesia, rigidez das extremidades e tremor. Sintomas reminiscentes destas disfunções motoras, assim como sinais não motores de doença de Parkinson, foram revelados num modelo transgénico de murganho, modelo este que expressa apenas 5% da proteína transportadora vesicular monoaminérgica (VMAT2-deficient). A doença de Parkinson é tipicamente tratada com o fármaco L-DOPA, um percursor da dopamina. Dado que a degradação da molécula de L-DOPA pela enzima catecol-O-metiltransferase (COMT) leva ao aumento dos níveis de homocisteína, um fator de risco cardiovascular e demência, a reposição terapêutica prolongada de dopamina poderá acelerar a disfunção neuronal e a neurodegeneração. Para além do uso de L-DOPA, tentativas anteriores para restaurar os níveis de dopamina e simultaneamente promoverem neuroprotecção não foram bem-sucedidas. Este estudo investigará os efeitos do inibidor enzimático da enzima COMT, Tolcapone, nas funções motoras, nas performances olfactiva e cognitiva, e mais tarde, na evolução dos marcadores bioquímicos de neurodegeneração e dos níveis sanguíneos de homocisteína em murganhos VMAT2-deficient. Propõe-se que o fármaco Tolcapone possa não só reduzir a degradação de L-DOPA mas adicionalmente favorecer o tratamento da doença de Parkinson aumentando e estabilizando os níveis de dopamina. Além disso, sugere-se ainda que a inibição farmacológica da enzima COMT oferece benefícios significativos a longo-prazo no contexto da doença de Parkinson: reduz o risco de episódios cardiovasculares, atrasa o aparecimento de declínio cognitivo, e sobretudo, oferece significativos efeitos neuroprotetores. Palavras-chave: doença de Parkinson, inibição de COMT, neurofarmacologia, modelo animal de PD, comportamento.
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- 2015
17. Contribution of microglia to neural inflammation : neuropeptide y modulates interleukin-1ß-induced microglia activation
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Ferreira, Raquel Margarida da Silva, Malva, João Oliveira, and Duarte, Conceição Pedrosa Duarte
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Neuropeptídeo y ,Microglia ,Sistema nervoso central -- inflamação - Abstract
Tese doutoramento em Ciências, apresentada à Universidade de Coimbra Neuropeptide Y (NPY) holds consistent neuroprotective and proneurogenic properties in the Central Nervous System (CNS). In light of growing evidence supporting a role for NPY in the regulation of the immune system, we sought to investigate the effect of this neuropeptide over several aspects of microglial response to inflammation, namely, the production of inflammatory mediators, cell motility and phagocytosis. In chapter 1, we investigated the role of NPY in the modulation of LPS-induced release of inflammatory mediators, such as nitric oxide (NO) and interleukin-10 (IL-10). Upon lipopolysaccharide (LPS, 100 ng/ml) stimulation, we found that microglial cells increased the expression of inducible nitric oxide synthase (iNOS), as well as the production of NO, as quantified by Griess Assay. Moreover, microglial cells co-stimulated with LPS and adenosine triphosphate (ATP, 1 mM) responded with a massive release of IL-10, as measured by ELISA. We observed that LPS (100 ng/ml) and IL-10 (1.5 ng/ml) stimulation induced NO production, a response prevented in the presence of a selective IL-1 receptor antagonist (IL-1ra, 150 ng/ml). Furthermore, LPS-induced NO production mediated by IL-10 occurred through a nuclear factor-kappaB (NF-kB)-dependent pathway. We observed that NPY inhibited IL-10 release and downstream nuclear translocation of NF-kB (determined by confocal microscopy and Western blotting), which is implicated in iNOS expression and NO synthesis. Pharmacological studies with a selective Y1 receptor agonist ([Leu31,Pro34]NPY, 1 μM) and selective antagonists for receptors Y1 (BIBP3226, 1 μM), Y2 (BIIE0246, 1 μM) and Y5 (L-152,804, 1 μM) demonstrated that NPY inhibition was mediated exclusively through Y1 receptor activation. In chapter 2, we investigated the role of NPY in the modulation of IL-10-induced microglial motility and the signaling pathway involved in this process. Interestingly, co-stimulation of microglial cells with LPS (100 ng/ml) and ATP (1 mM) resulted in increased cell motility, an effect inhibited by IL-1ra (150 ng/ml), which strongly suggested the participation of IL-10 in this process. In our scratch wound assay, we also observed that IL-10-induced motility was prevented by SB239063 (20 μM), a selective inhibitor of p38 mitogenactivated protein kinase (MAPK). IL-10 (1.5 ng/ml) induced p38 MAPK phosphorylation, followed by nuclear translocation, and this effect was inhibited by NPY via Y1 receptor activation, as observed by confocal microscopy and Western blotting. Likewise, p38 MAPK inhibition decreased the extent of actin filament reorganization occurring during plasma membrane ruffling. Given that both LPS and IL-10 induced significant alteration to the cell cytoskeleton, we proceeded to investigate the role of NPY in the regulation of LPS-induced microglial cell phagocytosis, in chapter 3. Accordingly, we observed that LPS (100 ng/ml) increased latex bead phagocytosis by microglia. Consistently, co-administration of LPS (100 ng/ml) and ATP (1 mM) increased bead phagocytosis and this effect was blocked by IL-1ra (150 ng/ml), suggesting the involvement of IL-10. Moreover, direct application of IL-10 (1.5 ng/ml) augmented the number of phagocytosed beads, while NPY acting through Y1 receptor activation inhibited this effect. To conclude, we assigned a novel role for NPY in the regulation of important microglial responses to danger signals in the brain, involving the production and release of inflammatory mediators, cell motility and phagocytosis. O neuropeptídeo Y (NPY) detém importantes propriedades neuroprotectoras e próneurogénicas no Sistema Nervoso Central (CNS). Dado o número crescente de evidências que sugerem um papel imuno-regulador para este neuropeptídeo, propusemo-nos estudar o efeito do NPY sobre vários aspectos da resposta da microglia à inflamação, nomeadamente, a produção de mediadores inflamatórios, motilidade celular e fagocitose. No capítulo 3, investigámos o papel do NPY na modulação da libertação de mediadores inflamatórios, tais como óxido nítrico (NO) e interleucina-10 (IL-10), após exposição a lipopolissacarídeo (LPS). Após estimulação com LPS (100 ng/ml), as células da microglia aumentaram a expressão da sintetase induzível do óxido nítrico (iNOS), assim como a produção de NO, quantificado com recurso ao ensaio de Griess. Adicionalmente, as células da microglia estimuladas com LPS e adenosina trifosfato (ATP, 1 mM) responderam com uma libertação massiva de IL-10, quantificado por ELISA. Observámos também que a exposição a IL-10 (1,5 ng/ml) induziu a produção de NO, uma resposta inibida na presença do antagonista selectivo para o receptor IL-1R (IL-1ra, 150 ng/ml). A produção de NO induzida por LPS é, assim, mediada por IL-10. Observámos que NPY inibiu a libertação de IL-10 e a translocação nuclear de NF-kB (determinada por microscopia confocal e por Western blotting), um processo implicado na expressão de iNOS e na síntese de NO. Uma abordagem farmacológica, recorrendo à utilização de um agonista para o receptor Y1 ([Leu31,Pro34]NPY, 1 μM), e de antagonistas para os receptores Y1 (BIBP3226, 1 μM), Y2 (BIIE0246, 1 μM) e Y5 (L-152,804, 1 μM) permitiu identificar o receptor Y1 como o principal responsável pelo efeito inibitório do NPY. No capítulo 4, investigámos o papel do NPY na modulação da motilidade da microglia induzida por IL-10, e a via de sinalização envolvida neste processo. A co-estimulação das células da microglia com LPS (100 ng/ml) e ATP (1 mM) resultou no aumento de motilidade celular, um processo inibido por IL-1ra (100 ng/ml), o que sugeriu o envolvimento de IL-10 neste processo. Com recurso a um ensaio de lesão, observámos que a motilidade induzida por IL-10 foi inibida por SB239063 (20 μM), um composto que inibe a activação da cinase p38. IL-10 (1,5 ng/ml) induziu a fosforilação da cinase p38, e a translocação da forma fosforilada para o núcleo. Este processo foi inibido por NPY através da activação do receptor Y1 (observado por microscopia confocal e Western blotting). Da mesma forma, a inibição da p38 diminui a reorganização dos filamentos de actina que ocorre durante o “ruffling” membranar, um processo que reflecte a expansão da membrana, durante a migração celular. No capítulo 5, investigámos o papel do NPY na regulação do processo fagocítico estimulado por LPS. Assim, observámos que LPS (100 ng/ml) aumentou o número de micro-esferas de látex fagocitadas por microglia. A co-administração de LPS (100 ng/ml) e ATP (1 mM) aumentou a fagocitose de micro-esferas de látex e este efeito foi bloqueado por IL-1ra (150 ng/ml), sugerindo o envolvimento de IL-10. A aplicação directa de IL-10 aumentou o número de micro-esferas fagocitadas, enquanto o NPY inibiu este efeito através da activação do receptor Y1. Em suma, atribuímos um novo papel ao NPY na regulação de respostas da microglia a sinais inflamatórios no cérebro, envolvendo a produção e libertação de mediadores inflamatórios, motilidade celular e fagocitose. Execution of this work was supported by Fundação para a Ciência e Tecnologia (FCT) and FEDER POCTI/SAU-FCF/58492/2004; POCTI/SAU-NEU/68465/2006. Grant reference: SFRH/BD/23595/2005
- Published
- 2010
18. Papel dos linfócitos CD4+ TH1 e TH17 na patogénese da encefalomielite autoimune experimental
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Domingues, Helena Sofia de Azevedo, Wekerie, Hartmut, and Malva, João Oliveira
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Células Th17 ,Encefalomielite ,Células Th1 - Abstract
Tese de doutoramento em Biologia (Biologia Celular) apresentada à Faculdade de Ciências e Tecnologia da Universidade de Coimbra Multiple sclerosis (MS) is an autoimmune disease that affects the central nervous system (CNS) and is characterized by inflammation, demyelination and axonal destruction, consequently leading to neuronal death. The processes that are involved in triggering the onset and driving inflammation, cellular composition and distribution of autoimmune lesions during the course of MS are not completely understood. Thus far, the animal model representing human MS, experimental autoimmune encephalomyelitis (EAE) has proved a central role for myelin‐autoimmune CD4+ helper T cells playing in the initiation of inflammatory demyelination of the CNS. In the past recent years, the scientific community has witnessed a real revolution regarding the knowledge of CD4+ T cell biology and this had, of course, an important impact in the understanding of many immune‐related diseases. Since the discovery in 2005 of the new Th17 cell subset, a big debate took place concerning the true pathogenic CD4+ T cell subset in EAE and MS. Th1 cells, which produce IFNγ as their signature cytokine, have for many years been considered to be the pathogenic effector T cells in CNS autoimmunity. However, unexpected data obtained together with the discovery of Th17 cells have led the researchers to believe that Th17 cells but not Th1 cells were pathogenic in EAE. Nevertheless, evidence coming from spontaneous EAE models developed in this lab suggested that both CD4+ T cell subsets, Th1 and Th17, may contribute to the pathogenesis, probably with different roles. Therefore, the main aim of this thesis was to address the roles of Th1 and Th17 cell subsets in the context of autoimmune disease of the CNS. Initially, by establishing an adoptive transfer EAE model, the individual pathogenicity of myelin‐specific Th1 and Th17 cells was evaluated in vivo and it was observed that both T cell lineages were able to induce EAE, but with different clinical features. While Th1 cells induced only classical paralytic EAE, many animals receiving Th17 cells developed an ataxic, non‐classical EAE phenotype. Interestingly, when Th1 and Th17 cells were cotransferred induced more severe EAE with earlier onset, indicating that these two CD4+ subsets are both pathogenic and synergize to trigger autoimmune inflammation in the CNS. Finally, it was found that transferred Th17 cells can convert to a Th1 phenotype in the host, suggesting plasticity in the Th17 cell subset and emphasizing a pathogenic role for Th1 cells. Next, taking into account our data and earlier findings previous to the Th17 cell discovery that demonstrated a cytotoxic capacity of auto‐antigenic T cells over astrocytes, important CNS resident glial cells, we asked which of the CD4+ T cell subset was cytotoxic to astrocytes. By establishing an in vitro co‐culture of myelin‐specific Th1 and Th17 cells with GFP positive‐astrocytes, it was possible to pursue cytotoxicity by fluorescent time‐lapse microscopy. It was found that Th1 but not Th17 cells were cytotoxic to astrocytes, further emphasizing the pathogenic role of Th1 cells. Finally, in order to identify molecules that are differently regulated in Th1 and Th17 cells and to understand which different roles these cells might play in EAE, a transcriptome analysis by microarrays of both populations was performed. We found the nuclear receptor Rev‐Erbα to be expressed in Th17 but not in Th1 cells. A pathway analysis revealed a relationship of Rev‐Erbα with RORα, an important transcription factor for Th17 differentiation, but no definite role for this molecule in regulating Th17 differentiation could be established. In conclusion, this thesis demonstrates, contrary to initial evidence, that both myelinspecific Th1 and Th17 CD4+ T cell subsets are able to induce pathogenicity in EAE, though with different capabilities to mediate disease. Also, Th1 cells are true cytotoxic effector cells destroying astrocytes, important neuronal buffer cells. A new gene was also discovered, Rev‐Erbα, which is differently regulated by Th1 and Th17 cells. Though no impact of Rev‐Erbα in Th17 differentiation could be determined, a possible role in Th17 biology will need to be further addressed. A Esclerose Múltipla (EM) é uma doença autoimune que afecta o Sistema Nervoso Central (SNC) e é caracterizada pela presença de inflamação, desmielinização e destruição axonal, levando, consequentemente, à morte neuronal. Os processos que despoletam e conduzem a resposta inflamatória, composição celular no SNC e distribuição das lesões autoimunes no curso da doença não são completamente conhecidos. Até ao momento, o modelo animal que representa a EM, a Encefalomielite Autoimune Experimental (EAE), tem sido essencial na identificação dos linfócitos CD4+ autoimunes, específicos para a mielina, como células centrais na iniciação das desmielinização inflamatória do SNC. Nos últimos anos, a comunidade científica tem assistido a uma revolução no conhecimento acerca da biologia das células T CD4+ ajudantes. Consequentemente, este facto teve um impacto extremamente importante na compreensão de muitas doenças relacionadas com o sistema imunitário. Desde a descoberta em 2005 do novo subtipo de células CD4+ ajudantes, as células Th17, uma grande controvérsia cresceu na discussão sobre o verdadeiro subtipo de células CD4+ patogénico na EAE e EM. As células Th1, que produzem IFNγ como principal citocina, foram durante muitos anos consideradas as células CD4+ patogénicas na EM e EAE. No entanto, evidências científicas paradoxais obtidas em paralelo com a descoberta das células Th17 levaram os investigadores a acreditar que, afinal, as células Th17, e não as Th1, eram as patogénicas na EAE. Em todo o caso, observações feitas nos modelos espontâneos para a EAE desenvolvidos no nosso laboratório sugeriram que, talvez, ambos os subtipos sejam importantes e contribuam para a patogénese, provavelmente com diferentes papéis. Assim, o principal objectivo desta tese consistiu na elucidação dos papéis individuais das células Th1 e Th17 no contexto da autoimunidade do SNC. Inicialmente, ao estabelecer um modelo de EAE por transferência adoptiva, avaliámos in vivo a patogenicidade individual das células Th1 e Th17 específicas para a mielina e descobrimos que ambos os subtipos são capazes de induzir EAE, embora com diferentes características clínicas. Ao passo que as células Th1 induziram apenas EAE clássica, muitos animais transferidos com células Th17 desenvolveram um fenótipo de 14 EAE não‐clássico, atáxico. Curiosamente, quando as células Th1 e Th17 foram transferidas em conjunto induziram EAE mais severa e com início de doença antecipado, indicando que estes dois subtipos de células CD4+ são ambos patogénicos e cooperam sinergicamente para despoletar inflamação autoimune no SNC. Finalmente, observámos que as células Th17 transferidas se converteram para o fenótipo Th1 no animal recipiente, sugerindo plasticidade das células Th17. Em seguida, tendo em conta os nossos resultados e observações anteriores à descoberta das células Th17 que demonstraram uma capacidade citotóxica de células T ajudantes e auto antigénicas, mediadoras de EAE, sobre astrócitos, questionou‐se qual subtipo seria o responsável por tal citotoxicidade. Após desenvolvimento de um sistema de co‐cultura de astrócitos GFP positivos com células Th1 e Th17 específicas para a mielina, foi possível avaliar a citotoxicidade por microscopia de fluorescência em tempo real. Descobrimos que são as células Th1, e não as Th17, citotóxicas para os astrócitos, enfatizando assim um papel patogénico das células Th1. Finalmente, com o objectivo de identificar moléculas reguladas de modo diferente pelas células Th1 e Th17 e que, de certo modo, possam explicar os diferentes papéis que estes subtipos possam ter na EAE, foi realizado uma análise do transcriptoma das duas populações por microarrays. O nosso estudo focou-se no receptor nuclear Rev‐Erbα, expresso nas células Th17 mas não nas Th1. Uma análise das vias celulares e relações moleculares revelou uma associação do Rev‐Erbα com o RORα, um importante factor de transcrição para a diferenciação das células Th17. No entanto, não foi possível definir um papel para este receptor na diferenciação das células Th17. Em suma, nesta tese de doutoramento foi possível demonstrar que, ao contrário das evidências iniciais, no nosso modelo de EAE ambos os subtipos de células T CD4+ específicos para a mielina, Th1 e Th17, são capazes de induzir patogenicidade na EAE. Ainda, mostrou-se que as células Th1, mas não as Th17, são citotóxicas para os astrócitos, importantes células protectoras dos neurónios no SNC. Descobrimos também que o receptor Rev‐Erbα é regulado de modo diferente pelas células Th1 e Th17. Apesar de não termos encontrado um papel relevante do Rev‐Erbα na diferenciação das células Th17, é possivel que exerça uma função importante na biologia das mesmas, que terá de ser explorada no futuro.
19. Neurotoxicidade e neuroprotecção no hipocampo : papel dos receptores do neuropeptídeo Y
- Author
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Silva, Ana Paula Pereira da, Carvalho, Caetana Monteiro de, and Malva, João Oliveira
- Subjects
Biologia celular
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