• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 18
  • 15
  • 8
  • 4
  • 3
  • 1
  • 1
  • Tagged with
  • 59
  • 59
  • 15
  • 14
  • 13
  • 12
  • 11
  • 11
  • 9
  • 9
  • 9
  • 8
  • 8
  • 7
  • 7
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

Targeted Delivery of a Therapeutic Protein for the Treatment of Alzheimer's Disease

Holman, Heather 01 January 2018 (has links) (PDF)
Neurodegenerative diseases such as Parkinson's disease and Alzheimer's disease are linked to mitochondrial dysfunction and the underexpression of TOM40, a protein with chaperone-like qualities that is responsible for transporting precursor proteins into the mitochondria. Overexpression of TOM40 is reported to partially restore mitochondrial dysfunction and decrease the accumulation of neurotoxic aggregates of α-synuclein. Our goal is to develop an effective method for delivery of TOM40 protein to the brain. Previous studies have used lentiviruses to carry TOM40 into the hippocampus of α-synuclein transgenic mice. The disadvantage of lentiviral transfection is the random insertions of the target gene into the host genome, which could cause toxic effects. Synthetic phospholipid vesicles containing TOM40 were considered as an alternative delivery method, but these "liposomes" elicit not only toxicity, but also an immune response. Thus, development of a safer delivery method of TOM40 protein is needed. We investigated exosomes, which are extracellular vesicles originating from multivesicular endosomes filled with protein, lipid, or RNA cargoes for cell-cell communication. Since exosomes are created from host cells, they are non-immunogenic and may be a more desirable method. Expression constructs have been made for the production of TOM40 protein within or on the surface of exosomes. In order to target the delivery of TOM40 to the brain, we attached peptides to the surface of the exosomes, which specifically interact with receptors on neural cells. We attempted to confirm the functionality of the expression constructs through immunocytochemistry followed by flow cytometry and Western blotting.
22

The Aryl Hydrocarbon Receptor Contributions to Cardiovascular Development and Health

Carreira, Vinicius S. January 2015 (has links)
No description available.
23

ROLE OF THE REACTIVE OXYGEN SPECIES PEROXYNITRITE IN TRAUMATIC BRAIN INJURY

Deng, Ying 01 January 2008 (has links)
Reactive oxygen species (ROS) is cytotoxic to the cell and is known to contribute to secondary cell death following primary traumatic brain injury (TBI). We described in our study that PN is the main mediator for both lipid peroxidation and protein nitration, and occurred almost immediately after injury. As a downstream factor to oxidative damage, the peak of Ca2+-dependent, calpainmediated cytoskeletal proteolysis preceded that of neurodegeneration, suggesting that calpain-mediated proteolysis is the common pathway leading to neuronal cell death. The time course study clearly elucidated the interrelationship of these cellular changes following TBI, provided window of opportunity for pharmacological intervention. Furthermore, we conducted a pharmacological study to solidify our hypothesis. First of all, we tested the potency of a membrane permeable, catalytic scavenger of PN-derived free radicals, tempol for its ability to antagonize PN-induced oxidative damage. Tempol successfully inhibited PNinduced protein nitration at dosages of 30, 100 and 300mg/kg. Moreover, early single dose of 300mg/kg was administered and isolated mitochondria were examined for respiratory function and oxidative damage level. Our data showed that tempol reduced mitochondrial oxidative damage, and maintained mitochondrial function within normal limits, which suggested that tempol is efficiently permeable to mitochondrial membrane and mitochondrial oxidative damage is essential to mitochondrial dysfunction. Next, we found that calpainmediated proteolysis is reduced at early treatment with a single dose of tempol. However, the effect of tempol on calpain is short-lived possibly due to systematic elimination. In our multiple dose study, tempol showed a significant inhibitory effect on SBDPs. Consequently, we measured neuordegeneration with the de Olmos aminocupric silver staining method at 7 days post-injury and detected a significant decrease of neuronal cell death. Together, the time course study and pharmacological study strongly support the hypothesis that PN is the upstream mediator in secondary cell death in the CCI TBI mouse model. Moreover, inhibition of PN-mediated oxidative damage with the antioxidant, tempol, is able to attenuate multiple downstream injury mechanisms. However, targeting PN alone may be clinically impractical due to its limited therapeutic window. This limitation may be overcome in future studies by a combination of multiple therapeutic strategies.
24

Avaliação quantitativa da função mitocondrial no músculo esquelético em pacientes com distrofia muscular de cinturas / Quantitative assessment of mitochondrial function in skeletal muscle of patients with limb-girdle muscular dystrophy

Bená, Marjory Irineu 18 October 2018 (has links)
As distrofias musculares de cinturas (DMC) representam um grupo heterogêneo de desordens hereditárias e degenerativas da musculatura esquelética, com evolução progressiva, caracterizadas principalmente pelo acometimento predominante das cinturas escapular e/ou pélvica. São classificadas de acordo com o padrão de herança e o gene envolvido, podendo ser autossômicas dominantes ou autossômicas recessivas. Embora as disfunções mitocondriais tenham sido pouco descritas nas DMC, alguns estudos apresentaram evidências morfológicas e bioquímicas de alterações secundárias na cadeia respiratória mitocondrial. As razões envolvidas em tais disfunções na DMC permanecem pouco compreendidas. Portanto, é imprescindível uma caracterização detalhada da disfunção mitocondrial nos pacientes com DMC para uma melhor compreensão dos processos fisiopatológicos envolvidos na doença. Os objetivos do estudo foram: quantificar a CoQ10 em fragmentos do músculo esquelético de pacientes com DMC; quantificar a atividade enzimática de cada complexo da cadeia respiratória isoladamente; quantificar a atividade dos complexos II+III em conjunto como avaliação indireta da CoQ10; verificar a relação entre a área relativa de fibras musculares no fragmento de biópsia e o grau de disfunção mitocondrial nesses fragmentos; correlacionar a função mitocondrial com parâmetros clínicos de pacientes com DMC. Participaram do estudo 21 pacientes com DMC e 9 controles saudáveis. Os parâmetros clínicos incluídos foram idade no momento da biópsia, idade de início dos sintomas e tempo de evolução da doença. A análise do metabolismo mitocondrial foi realizada por: quantificação da coenzima Q10 nos fragmentos de biópsia muscular e quantificação da atividade dos complexos enzimáticos mitocondriais I, II, III, II+III e IV da cadeia respiratória e da enzima da matriz mitocondrial citrato sintase. Foram correlacionados os parâmetros clínicos, a proporção de fibras na biópsia muscular e os resultados das análises bioquímicas para a caracterização da função mitocondrial. A média dos pacientes com DMC em relação à idade no momento da biópsia, início dos sintomas e tempo de evolução da doença foi de 28,9 anos (DP ±11,7), 16,7 anos (DP ±10,3) e 12,1 anos (DP ±10,9), respectivamente. O grupo controle apresentou média de idade no momento da biópsia de 29,6 anos (DP ±10,3). A dosagem média de CoQ10 nos fragmentos de biópsia de pacientes com DMC foi de 17,9 µg/g de tecido (DP ±9,2) e nos fragmentos dos controles foi de 29,5 µg/g de tecido (DP ±4,4). Não foi observada alteração das atividades isoladas dos complexos enzimáticos da cadeia respiratória. Houve deficiência da atividade do conjunto de complexos II+III nos pacientes com DMC. A média da área ocupada por fibras musculares nos pacientes com DMC foi de 58,5% (DP ±26,1%) e nos controles foi de 76,35% (DP ±1,9%). Observou-se correlação moderada entre a quantidade de CoQ10 e a área relativa de fibras musculares (r= 0,57 e p= 0,007). Não houve correlação da CoQ10 com os parâmetros clínicos. No presente estudo, concluímos que existe uma deficiência secundária de CoQ10 em pacientes com DMC, sendo um achado importante para melhor entendimento do acometimento mitocondrial nessa doença e uma abordagem terapêutica mais eficaz. / The limb-girdle muscular dystrophy (LGMD) is a group of inherited and degenerative disorders of the skeletal muscle, with a progressive clinical course and predominant involvement of the scapular and/or pelvic girdles. They are classified according to the pattern of inheritance (autosomal dominant or autosomal recessive) and the gene involved. Mitochondrial dysfunction has been reported in the LGMD, some studies have described morphological and biochemical evidences of secondary mitochondrial respiratory chain alterations in patients with LGMD. The reasons involved in such dysfunctions in the LGMD remain poorly understood. Therefore, a detailed characterization of the mitochondrial dysfunction in patients with LGMD allows a better understanding of the pathophysiological processes involved in the disease. Therefore, a detailed characterization of mitochondrial dysfunction in patients with LGMD is essential for a better understanding of the pathophysiological processes involved in the disease. The purposes of the study were: to quantify CoQ10 in fragments of muscle biopsy of patients with LGMD; quantify the enzymatic activity of each respiratory chain complex isolated; quantify the activity of the II + III complexes together as an indirect measure of CoQ10; to verify the relation between the relative area of muscular fibers in the fragment of biopsy and the degree of mitochondrial dysfunction in these fragments; correlate mitochondrial function with clinical parameters of patients with LGMD. Twenty-one patients with LGMD and nine healthy controls participated in the study. The clinical parameters included were age at the time of biopsy, age of onset of symptoms and time of disease progression. The analysis of mitochondrial metabolism was performed by: quantification of CoQ10 in the muscle biopsy fragments and quantification of the activity of the mitochondrial enzyme complexes I, II, III, II + III and IV of the respiratory chain and the enzyme of the mitochondrial matrix citrate synthase. We analyzed the correlation of the clinical parameters, the proportion of fibers in the muscle biopsy and the results of the biochemical analyzes for the characterization of the mitochondrial function. For the LGMD groups, the mean age at the time of biopsy, onset of symptoms and disease duration was 28.9 years (SD ± 11.7), 16.7 years (SD ± 10.3) and 12.1 years (SD ± 10.9), respectively. The control group presented a mean age at the time of biopsy of 29.6 years (SD ± 10.3). The mean CoQ10 dosage in the biopsy specimens of patients with LGMD was 17.9 ?g / g tissue (SD ± 9.2) and in the fragments of the controls was 29.5 ?g / g tissue (SD ± 4, 4). No alterations were observed in the isolated activities of the enzymatic complexes of the respiratory chain. There was a deficiency of the activity of complexes II + III in patients with LGMD. The mean area occupied by muscle fibers in patients with LGMD was 58.5% (SD ± 26.1%) and in controls it was 76.35% (SD ± 1.9%). A moderate correlation was observed between the amount of CoQ10 and the relative area of muscle fibers (r = 0.57 and p = 0.007). There was no correlation of CoQ10 with clinical parameters. In the present study, we conclude that there is a secondary deficiency of CoQ10 in patients with LGMD, which has important implications in the understanding of mitochondrial involvement in this group of diseases and the development of a more effective therapeutic approach.
25

Organoselenotriazóis atenuam o estresse oxidativo induzido por disfunção mitocondrial em Caenorhabditis elegans / Organoselenotriazoles attenuate the oxidative stress induced by mitochondrial dysfunction in Caenorhabditis elegans

Soares, Ana Thalita Gonçalves 21 December 2017 (has links)
Submitted by Marcos Anselmo (marcos.anselmo@unipampa.edu.br) on 2018-09-26T14:13:20Z No. of bitstreams: 1 Ana Thalita Soares.pdf: 894559 bytes, checksum: 0be887f2c20f60f2861f46e074b8733b (MD5) / Approved for entry into archive by Marcos Anselmo (marcos.anselmo@unipampa.edu.br) on 2018-09-26T14:13:42Z (GMT) No. of bitstreams: 1 Ana Thalita Soares.pdf: 894559 bytes, checksum: 0be887f2c20f60f2861f46e074b8733b (MD5) / Made available in DSpace on 2018-09-26T14:13:42Z (GMT). No. of bitstreams: 1 Ana Thalita Soares.pdf: 894559 bytes, checksum: 0be887f2c20f60f2861f46e074b8733b (MD5) Previous issue date: 2017-12-21 / Compostos orgânicos de Selênio possuem diversas atividades farmacológicas já descritas, como atividade anti-inflamatória e antitumoral, principalmente devido aos seus efeitos antioxidantes. Por serem promissores na farmacologia, as sínteses desses compostos tem aumentado significativamente. Como muitas novas moléculas são sintetizadas o uso de um modelo simples como Caenorhabditis elegans é altamente vantajoso para avaliação inicial da toxicidade e do potencial terapêutico destas moléculas. O objetivo desse estudo foi avaliar a toxicidade e o potencial antioxidante de três compostos Arilselanil-alquil-1,2,3-triazois em C. elegans. Os animais foram expostos aos compostos em meio liquido por apenas 30 minutos no primeiro estagio larval (L1). Os compostos testados não apresentaram efeitos tóxicos nas concentrações testadas (1μM-1000 μM) em C. elegans. O tratamento com os Arilselanil-alquil-1,2,3-triazois (10 μM) reverteu parcialmente o estresse induzido pelo pesticida paraquat (1 mM), uma toxina mitocondrial. Apenas o composto SeTz-2 (10 μM) aumentou parcialmente a sobrevivência dos vermes tratados com H2O2 (0,5 mM). Os compostos também aumentaram a longevidade dos vermes mutantes mev-1, que possuem um reduzido tempo de vida pela produção em excesso de EROs na mitocôndria causada por uma alteração no complexo 2 da cadeia transportadora de elétrons. Além disso, os compostos reduziram os níveis de espécies reativas de oxigênio determinados pelo probe fluorescente H2DCF-DA bem como também reduziram a atividade da enzima catalase nesses animais mutantes. Baseado nos resultados encontrados é possível concluir que os compostos Arilselanil-alquil-1,2,3-triazois possuem atividade antioxidante principalmente em condição de estresse oxidativo mitocondrial em C. elegans. / Organic selenium molecules have many described pharmacological activities, such as anti-inflammatory and anti-tumoral, which are mainly due to their antioxidant effects. As they are promising pharmacological agents, their synthesis has grown significantly. Once many new molecules synthesized every day, the use of a simple animal model, such as the Caenorhabditis elegans, is highly valuable for initial toxicity and pharmacological potential evaluation of these molecules. The goal of this study was to evaluate the toxicity and the antioxidant capacity of three arylselanyl-alkyl-1,2,3-triazoles in C. elegans. The animals were exposed to the molecules in liquid media for 30 minutes at the first larval stage (L1). There were no toxic effects over animals’ viability within the range of tested concentrations (1μM-1000 μM). Exposure to 10 μM of arylselanyl-alkyl-1,2,3-triazoles has partially reversed the stress induced by the pesticide paraquat (1 mM), which is a mitochondrial toxin. Only SeTz-2 (10 μM) improved the viability of the animals exposed to H2O2 (0,5 mM). The arylselanyl-alkyl-1,2,3-triazoles also improved mev-1 mutants’ lifespan, which is normally decreased by excessive mitochondrial ROS production due to an alteration in a subunit of their mitochondrial complex 2. Also, the molecules were able to reduce ROS levels measured by the fluorescent probe H2DCF-DA, as well as they also reduced catalase enzyme’ activity. Based on our findings, it is possible to suggest that these molecules have antioxidant activity in C. elegans, mainly when facing mitochondrial oxidative stress.
26

Parkinson's disease : experimental in vitro model validation and the potential role of cofilin-1 in the pathophysiological mechanisms

Lopes, Fernanda Martins January 2017 (has links)
The dopaminergic neurodegeneration in the substantia nigra pars compacta (SNpc) is responsible for the marked motor impairment observed in Parkinson's disease (PD). However, the molecular mechanisms underlying this are not completely understood. Since by the time of diagnosis, 50-70% of the dopaminergic neurons of the nigrostriatal pathway have already been degenerated, it is difficult to investigate the early-stage events of disease pathogenesis. Due to inaccessibility of the human brain to study initial pathogenic mechanisms of the disease, experimental models have been developed in an attempt to elucidate PD etiology and its progression. Nevertheless, PD models are a controversial issue in neuroscience research since it is challenging to mimic human neuronal complexity. Therefore, the lack of optimal models that recreate disease pathology is one of the causes of failure of clinical trials that have attempted to find new/better PD therapies. Taking this in consideration, the development of more suitable models is necessary to improve our knowledge regarding PD etiological mechanisms. Additionally, the understanding of the advantages and disadvantages of models already established would also be beneficial for PD research, which our group addressed by reviewing this subject. Considering this, we chose SH-SY5Y cells as a PD model for our studies. To investigate the initial stages of PD-induced neurodegeneration, our work focused in the role of cofilin-1, a protein involved in mitochondrial dysfunction caused by oxidant-induced-apoptosis, which are two pathogenic processes strongly related to PD. Hence, in the thesis, we aimed to validate the use of retinoic-acid-(RA)-differentiated SH-SY5Y cells as an in vitro model and use it to investigate the potential role of cofilin-1 in the initial molecular and cellular mechanisms of PD. Although SH-SY5Y cells are widely used in PD research, their major drawback is their lack of important neuronal features, such as low levels of proliferation and stellate morphology. On the other hand, SH-SY5Y cells can acquire a neuronal phenotype when treated with differentiation agents such as RA. Since several protocols have been described, the consequence of which may be the discrepancies observed among studies regarding neuronal and dopaminergic features. In Chapter I, we aimed to validate a RA-differentiation protocol for SH-SY5Y cells previously established by our research group, focusing upon characterization of neuronal features and its subsequent response to 6-hydroxydopamine (6-OHDA), a toxin widely used to induce dopaminergic degeneration. RA-differentiated SH-SY5Y cells have low proliferative rates, a pronounced neuronal morphology and high expression of genes related to synapse vesicle cycle, dopamine synthesis/degradation, and dopamine transporter (DAT). After exploring phenotypic differences between these two models, we verified that RA-differentiated cells were more sensitive to 6-OHDA toxicity than undifferentiated cells, which could be related to an increase of DAT immunocontent. Many lines of evidence have showed that DAT is responsible for 6-OHDA uptake in vivo. Once inside the neuron, 6-OHDA underwent auto-oxidation causing a significant increase in oxidative stress. However, toxin uptake is not an essential step in undifferentiated SH-SY5Y cells, as auto-oxidation occurs extracellularly. We showed here, for the first time, that RA-differentiated SH-SY5Y cells can mimic, at least in part, an important mechanism of the 6-OHDA-induced cell death found in previous in vivo studies. Hence, the cellular model established by our research group presents essential neuronal features, being a suitable model for PD research. In Chapter II, RA-differentiated SH-SY5Y cells were used as cellular model to investigate disease molecular mechanisms, focusing upon cofilin-1. Our previous data have shown that oxidation of non-phosphorylate (activated) cofilin-1 leads to mitochondrial dysfunction and cell death induced by apoptosis in tumour cells. Here we found that cofilin-1 played a role in early stages of neuronal apoptosis induced by 6-OHDA in our cellular model since cofilin-1 mitochondrial translocation precedes organelle dysfunction. Overexpression of wild type CFL1 resulted in increased sensitivity of SH-SY5Y cells to 6-OHDA-induced neuronal cell death. Furthermore, overexpression of non-oxidizable CFL1 containing Cys-to-Ala mutations (positions 39, 80 and 139) increased neuronal resistance to this toxin, suggesting that oxidation is an important step in 6-OHDA toxicity. Follow-up experiments were performed in order to evaluate clinically whether cofilin-1 pathway proteins content is altered in PD post mortem human brain. Our findings showed a significant decrease in p-cofilin-1/cofilin-1 ratio in PD patients, which indicates an increase in the amount of activated cofilin-1 available for oxidation. Moreover, through principal component analysis, the immunodetection of cofilin-1 pathway proteins were able to discriminate controls and PD individuals during the early-stage of neuropathological changings. Hence, we demonstrated, for the first time, a possible role for cofilin-1 in PD pathogenesis and its potential use as biomarker. Taken together, our data showed that RA-differentiated SH-SY5Y cells present terminally-differentiated dopaminergic neuron features, that are essential to mimic dopaminergic neurons. By using this cellular model and post mortem brain tissue, we also demonstrated a possible role for cofilin-1 in early steps of the neurodegeneration process found in PD, which it could impact drug and biomarker discovery researches.
27

Mitochondriální dysfunkce a neurodegenerativní onemocnění / Mitochondrial dysfunction and neurodegenerative diseases

Novotná, Veronika January 2018 (has links)
Charles University in Prague Faculty of Pharmacy in Hradec Králové Department of Biological and Medical Sciences Author: Bc. Veronika Novotná Supervisor: doc. MUDr. Josef Herink, DrSc. Title of diploma thesis: Mitochondrial dysfunction and neurodegenerative diseases The diploma thesis deals with mitochondrial dysfunction and neurodegenerative diseases and it is divided into two main parts. The first part summarized the classification of neurodegenerative diseases and general charakteristic of mitochondria.Then a describe of the processes of oxidative stress, excitotoxicity, apoptosis and briefly decribe the nervous system. The second part deals with description of mitochondrial dysfunction in selected nerodegenerative diseases. The recent studies refer to connection between mitochondrial dysfunctions and formation of neurodegenerative diseases. Keywords: excitotoxicity, mitochondrial dysfunction, neurodegenerative disorders, neuronal cell death, oxidative damage
28

Parkinson's disease : experimental in vitro model validation and the potential role of cofilin-1 in the pathophysiological mechanisms

Lopes, Fernanda Martins January 2017 (has links)
The dopaminergic neurodegeneration in the substantia nigra pars compacta (SNpc) is responsible for the marked motor impairment observed in Parkinson's disease (PD). However, the molecular mechanisms underlying this are not completely understood. Since by the time of diagnosis, 50-70% of the dopaminergic neurons of the nigrostriatal pathway have already been degenerated, it is difficult to investigate the early-stage events of disease pathogenesis. Due to inaccessibility of the human brain to study initial pathogenic mechanisms of the disease, experimental models have been developed in an attempt to elucidate PD etiology and its progression. Nevertheless, PD models are a controversial issue in neuroscience research since it is challenging to mimic human neuronal complexity. Therefore, the lack of optimal models that recreate disease pathology is one of the causes of failure of clinical trials that have attempted to find new/better PD therapies. Taking this in consideration, the development of more suitable models is necessary to improve our knowledge regarding PD etiological mechanisms. Additionally, the understanding of the advantages and disadvantages of models already established would also be beneficial for PD research, which our group addressed by reviewing this subject. Considering this, we chose SH-SY5Y cells as a PD model for our studies. To investigate the initial stages of PD-induced neurodegeneration, our work focused in the role of cofilin-1, a protein involved in mitochondrial dysfunction caused by oxidant-induced-apoptosis, which are two pathogenic processes strongly related to PD. Hence, in the thesis, we aimed to validate the use of retinoic-acid-(RA)-differentiated SH-SY5Y cells as an in vitro model and use it to investigate the potential role of cofilin-1 in the initial molecular and cellular mechanisms of PD. Although SH-SY5Y cells are widely used in PD research, their major drawback is their lack of important neuronal features, such as low levels of proliferation and stellate morphology. On the other hand, SH-SY5Y cells can acquire a neuronal phenotype when treated with differentiation agents such as RA. Since several protocols have been described, the consequence of which may be the discrepancies observed among studies regarding neuronal and dopaminergic features. In Chapter I, we aimed to validate a RA-differentiation protocol for SH-SY5Y cells previously established by our research group, focusing upon characterization of neuronal features and its subsequent response to 6-hydroxydopamine (6-OHDA), a toxin widely used to induce dopaminergic degeneration. RA-differentiated SH-SY5Y cells have low proliferative rates, a pronounced neuronal morphology and high expression of genes related to synapse vesicle cycle, dopamine synthesis/degradation, and dopamine transporter (DAT). After exploring phenotypic differences between these two models, we verified that RA-differentiated cells were more sensitive to 6-OHDA toxicity than undifferentiated cells, which could be related to an increase of DAT immunocontent. Many lines of evidence have showed that DAT is responsible for 6-OHDA uptake in vivo. Once inside the neuron, 6-OHDA underwent auto-oxidation causing a significant increase in oxidative stress. However, toxin uptake is not an essential step in undifferentiated SH-SY5Y cells, as auto-oxidation occurs extracellularly. We showed here, for the first time, that RA-differentiated SH-SY5Y cells can mimic, at least in part, an important mechanism of the 6-OHDA-induced cell death found in previous in vivo studies. Hence, the cellular model established by our research group presents essential neuronal features, being a suitable model for PD research. In Chapter II, RA-differentiated SH-SY5Y cells were used as cellular model to investigate disease molecular mechanisms, focusing upon cofilin-1. Our previous data have shown that oxidation of non-phosphorylate (activated) cofilin-1 leads to mitochondrial dysfunction and cell death induced by apoptosis in tumour cells. Here we found that cofilin-1 played a role in early stages of neuronal apoptosis induced by 6-OHDA in our cellular model since cofilin-1 mitochondrial translocation precedes organelle dysfunction. Overexpression of wild type CFL1 resulted in increased sensitivity of SH-SY5Y cells to 6-OHDA-induced neuronal cell death. Furthermore, overexpression of non-oxidizable CFL1 containing Cys-to-Ala mutations (positions 39, 80 and 139) increased neuronal resistance to this toxin, suggesting that oxidation is an important step in 6-OHDA toxicity. Follow-up experiments were performed in order to evaluate clinically whether cofilin-1 pathway proteins content is altered in PD post mortem human brain. Our findings showed a significant decrease in p-cofilin-1/cofilin-1 ratio in PD patients, which indicates an increase in the amount of activated cofilin-1 available for oxidation. Moreover, through principal component analysis, the immunodetection of cofilin-1 pathway proteins were able to discriminate controls and PD individuals during the early-stage of neuropathological changings. Hence, we demonstrated, for the first time, a possible role for cofilin-1 in PD pathogenesis and its potential use as biomarker. Taken together, our data showed that RA-differentiated SH-SY5Y cells present terminally-differentiated dopaminergic neuron features, that are essential to mimic dopaminergic neurons. By using this cellular model and post mortem brain tissue, we also demonstrated a possible role for cofilin-1 in early steps of the neurodegeneration process found in PD, which it could impact drug and biomarker discovery researches.
29

Propriedades neurofarmacológicas da Euterpe oleracea: estudo in vitro do potencial uso no tratamento de doenças psiquiátricas / Neuropharmacological properties of Euterpe oleracea: an in vitro study of the potential use at psychiatric illness treatment

Machado, Alencar Kolinski 26 January 2017 (has links)
Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq / Neuropsychiatric diseases, as bipolar disorder (BD), have a very complex pathophysiology. Several times the diagnostic and to choose a correct treatment are difficult. Currently, have been developed studies related to mechanisms that can be associated with specific biomarkers present on mental illness. Some studies are describing an association between neuropsychiatric diseases and mitochondrial dysfunction and consequent cellular modifications. Additionally, some psychiatric illnesses are been associated with chronic inflammatory activation via pro-inflammatory cytokines production. In this sense, the search for drug development to treat psychiatric illness is very necessary. Euterpe oleracea, known as açaí, is an Amazonian fruit and a potential candidate for neuropharmacological study due to chemical matrix, including a variety of bioactive compounds with biological effects. There are molecules that could act at mitochondrial function and neurophysiology. Objective: to perform a literature review about the mitochondrial dysfunction impact at bipolar disorder and chemically analyse and evaluate the neupharmacological in vitro effect of açaí extract through mitochondrial function modulation and oxidative and inflammatory metabolisms. Methodology: initially we produced a review about the association between BD and cellular mitochondrial metabolism based on scientific articles published at last 20 years in different journals found at PUBMED-MEDLINE of American library. This review helped to create the ecperimental in vitro design of this study. After, we performed an in vitro experimental research using a cell line SH-SY5Y exposed to rotenone. SH-SY5Y cells were obtained from American Type Culture Collection (ATCC®), and treated with freeze-dried hydroalcoholic açaí extract which was analyzed by high performance liquid chromatography. Initially the açaí effect at cell viability was measured through different concentration-effect curves. We also induced mitochondrial complex I dysfunction using rotenone at 5, 15 and 30 nM. Before and after rotenone exposition 5 μg/mL of açaí extract was added to evaluate the potential effect of açaí to prevent and reverse rotenone damages. After all treatments were performed experimental assays to evaluate the mitochondrial transport chain, the mitochondrial complex I enzyme activity, the protein and gene expression of NDUFS7, S8, V1 and V2 of complex I, the total levels of reactive oxygen species and lipid peroxidation. For the third study we used RAW 264.7 macrophages from ATCC. Cells were activated with PHA and exposed to different concentrations of açaí extract during 72h. Using the most anti-inflammatory effective concentration of açaí extract, we developed all another experimental assays to evaluate oxidative metabolism parameters, cell cycle and protein expression of cytokines and NLRP3-inflammasome. The statistical analysis was performed by one way anova followed by Tukey or Dunnett post hoc. Results: the obtained results were organized in three scientific articles. The review paper was published at Canadian Journal of Psychiatry and indicated the relevance of studies that dentify plants with potential properties to modulate mitochondrial complex I. The obtained results of second study were published at Oxidative and Cellular Longevity journal where we observed that hydroalcoholic açaí extract presented high levels of orientin (8,05±0,03mg/g), p-cumaric acid (3,52±0,01mg/g) and apigenin (3,49±0,01mg/g). In vitro results related to mitochondrial dysfunction and oxidative stress showed that the most effective concentration of açaí extract was 5μg/mL after 48h of incubation. We observed that açaí extract at both experimental models presented protective effects under mitochondrial complex I and this effect was due to an increased protein and gene expression mainly for NDUFS7 and S8 subunits that form the active region of this complex. Despite, was observed a decreased rate of reactive oxygen species and of lipid peroxidation under açaí exposition. Results of third study were organized in a manuscript that will be submitted for publication at Inflammation Research journal. It was observed the anti-inflammatory activity of açaí in macrophage PHA-induced, where the effective concentration able to reduce 50% of cellular proliferation (EC50) 1 μg/mL. Complementary assays showed that this specific concentration is capable to decrease inflammatory markers as proliferation rate, cell cycle, ROS levels and nitric oxide. Açaí also reduced pro-inflammatory cytokines levels (IL-1β, IL-6, TNFα. INFγ), and the inflammasome NLRP3, increasing IL-10 levels. Conclusion: the results obtained until this moment are suggesting that açaí has neuropharmacological activity and is a potential candidate for drug development or food supplement for psychiatric diseases treatment, especially BD which is related to mitochondrial complex I dysfunction and chronic inflammatory activation. / As doenças neuropsiquiátricas, como o transtorno bipolar, possuem fisiopatologia bastante complexa. Muitas vezes o diagnóstico e a escolha de um tratamento eficaz são de difícil realização. Atualmente vêm sendo desenvolvidos estudos relacionados aos mecanismos causais e que podem ser direcionados a descoberta de novos biomarcadores característicos de doenças mentais. Alguns estudos descrevem a existência de uma forte associação entre doenças neuropsiquiátricas e disfunção mitocondrial e consequentes alterações celulares. Adicionalmente, algumas doenças psiquiátricas estão também associadas à inflamação crônica, via produção de citocinas pró-inflamatórias. Dessa forma, a busca pelo desenvolvimento de novos fármacos para o tratamento de doenças psiquiátricas é de grande necessidade. A Euterpe oleracea, espécie conhecida popularmente como açaí, é uma fruta amazônica potencial candidata a estudos neurofarmacológicos devido a sua constituição química que inclui uma variedade de moléculas bioativas que poderiam atuar tanto melhorando a função mitocondrial e a resposta inflamatória. Objetivo: realizar revisão da literatura sobre o impacto da disfunção mitocondrial no transtorno bipolar, caracterizar quimicamente e avaliar o potencial efeito neurofarmacológico in vitro do extrato de açaí na modulação da função mitocondrial, do metabolismo oxidativo e inflamatório. Metodologia: inicialmente foi produzido um estudo de revisão teórico-literário sobre a associação entre o transtorno bipolar e o metabolismo mitocondrial celular baseado em artigos científicos publicados nos últimos 20 anos em revistas indexadas no PUBMED-MEDLINE da Biblioteca dos Estados Unidos da América. Esta revisão auxiliou na concepção do delineamento da parte experimental do trabalho. A pesquisa experimental in vitro foi feita utilizando-se a linhagem comercial SH-SY5Y expostas a rotenona. As células SH-SY5Y foram obtidas da American Type Culture Collection (ATCC®) e foram tratadas com um extrato hidroalcólico de açaí liofilizado, no qual as principais substâncias bioativas foram quantificadas por Cromatografia Líquida de Alta Eficiência (CLAE). O efeito do açaí sobre a viabilidade celular foi avaliado através de diferentes curvas concentração-efeito. Foi induzida disfunção no complexo I mitocondrial através do uso da rotenona nas concentrações de 5, 15 e 30 nM. Antes ou após o tratamento com rotenona, foi adicionado o extrato de açaí (5 μg/mL) a fim de avaliar a capacidade de prevenção e/ou reversão dos efeitos da rotenona. Após os tratamentos, foram desenvolvidos ensaios experimentais de avaliação da cadeia de transporte de elétrons, da atividade enzimática do complexo I mitocondrial, da expressão proteica e gênica das subunidades NDUFS7, S8, V1 e V2, da taxa total de espécies reativas de oxigênio e da lipoperoxidação. Já para o terceiro estudo, foi utilizada linhagem celular de macrófagos RAW 264.7, também obtidos da ATCC. Tais células foram ativadas com fitohemaglutinina (PHA) e expostas a diferentes concentrações de extrato de açaí durante 72h. Com base na concentração mais efetiva do extrato (1 μg/mL) frente à inflamação, foram realizadas as avaliações de parâmetros do metabolismo oxidativo, do ciclo celular e da expressão de citocinas inflamatórias e do inflamassoma NLRP3, via diferentes métodos experimentais. Os resultados foram estatisticamente comparados por análise de variância de uma via seguida de teste post hoc de Tukey ou Dunnet. Resultados: os resultados obtidos foram organizados sob a forma de três artigos científicos. A revisão de literatura foi publicada no Canadian Journal of Psychiatry e indicou a relevância de estudos que identifiquem plantas com potencial propriedade de modular o complexo I mitocondrial. Os resultados obtidos no segundo estudo foram publicados na revista Oxidative Medicine and Cellular Longevity onde se observou que o extrato hidroalcoólico de açaí apresentou níveis elevados das seguintes moléculas: orientina (8,05±0,03 mg/g), ácido p-cumárico (3,52±0,01 mg/g) e apigenina (3,49±0,01 mg/g). Os resultados in vitro relacionados à disfunção mitocondrial e estresse oxidativo mostraram que a concentração mais efetiva do extrato hidroalcoólico de açaí que aumentou a viabilidade celular foi a de 5 μg/mL após 48h de incubação. Foi observado que o extrato de açaí em ambos os modelos experimentais apresentou efeito protetor sobre o complexo I mitocondrial e este efeito deveu-se ao aumento da expressão proteica e gênica principalmente das subunidades NDUFS7 e S8 que constituem a região de atividade deste complexo. Além disso, foi evidenciada redução da taxa total de espécies reativas de oxigênio (EROs) e diminuição dos níveis de peroxidação lipídica. Os resultados do terceiro estudo foram organizados sob a forma de um manuscrito a ser submetido à revista Inflammation Research. Nele foi observada atividade anti-inflamatória do açaí em macrófagos RAW PHA-ativados, sendo a concentração estimada para diminuir em 50% a resposta inflamatória (EC50) de 1 μg/mL. Testes complementares mostraram que esta concentração foi capaz diminuir marcadores inflamatórios como taxa de proliferação celular, ciclo celular, níveis de EROs e de óxido nítrico. O açaí também reduziu os níveis de citocinas pró-inflamatórias (IL-1β, IL-6, TNFα. INFγ) e relacionadas ao inflamassoma NLRP3, e também aumentou os níveis da citoticina anti-inflamatória IL-10. Conclusão: os resultados obtidos sugerem que o açaí possui atividade neurofarmacológica e que é um potencial candidato no desenvolvimento de novos fármacos ou suplementos alimentares direcionados ao tratamento de doenças psiquiátricas, em especial o transtorno bipolar que está relacionado à disfunção do complexo I mitocondrial e à ativação inflamatória crônica.
30

O treinamento resistido previne a disfunção mitocondrial no córtex pré-frontal e no músculo vasto lateral de ratas ovariectomizadas

Rossini, Juliana 29 April 2016 (has links)
Submitted by Bruna Rodrigues (bruna92rodrigues@yahoo.com.br) on 2016-10-25T11:59:03Z No. of bitstreams: 1 DissJR.pdf: 2471700 bytes, checksum: 1cec0d156c66d81384b97543e61cdf97 (MD5) / Approved for entry into archive by Marina Freitas (marinapf@ufscar.br) on 2016-11-08T19:06:32Z (GMT) No. of bitstreams: 1 DissJR.pdf: 2471700 bytes, checksum: 1cec0d156c66d81384b97543e61cdf97 (MD5) / Approved for entry into archive by Marina Freitas (marinapf@ufscar.br) on 2016-11-08T19:06:40Z (GMT) No. of bitstreams: 1 DissJR.pdf: 2471700 bytes, checksum: 1cec0d156c66d81384b97543e61cdf97 (MD5) / Made available in DSpace on 2016-11-08T19:06:47Z (GMT). No. of bitstreams: 1 DissJR.pdf: 2471700 bytes, checksum: 1cec0d156c66d81384b97543e61cdf97 (MD5) Previous issue date: 2016-04-29 / Não recebi financiamento / Introduction: As we age, human body goes through several important physiological changes, especially in women after menopause, during which estrogen levels are declining, causing changes in mitochondrial function both in skeletal muscle and brain. Menopause is mimicked experimentally by a technique called ovariectomy, that causes some alterations in rats, such as the loss of muscle mass (sarcopenia); however studies have demonstrated that loss of age-related muscle is a different process from strength loss. Whereas the loss of muscle strength is dissociated from this condition, it was renamed as dinapenia. Resistance Training (RT) has beneficial effects on postmenopausal women, but is not well established in the literature the possible effects of RT on mitochondrial function of the cerebral motor cortex and skeletal muscle of ovariectomized rats. Objective: This study aimed to investigate the effects of ovariectomy and resistance training on mitochondrial function (oxygen consumption) in tissue biopsy of the prefrontal cortex and vastus lateralis muscle (VL) in rats. Materials and Methods: were used 40 adult female rats divided into 4 experimental groups (Sham-SED, Sham- TR, OVX-SED and OVX-TR). The ovariectomy was performed at 13 weeks. The Resistance Training (RT) proposed was the climb stairs model, and held for 13 weeks. The masses of the prefrontal cortex, cerebellum, Vastus Lateralis (VL) and Retus Femoralis (RF) were analyzed after sacrifice, which took place 48 hours after the last training session. Oxygen consumption and mitochondrial respiratory parameters were performed on tissue biopsy of the prefrontal cortex and the vastus lateralis (VL) by technique of High Resolution Respirometry (Oroboros®). Results: it was found decreased muscle mass (VL and RF), as well as the cerebellum in OVX-SED group compared to other groups (p <0.05). TR prevented the loss of muscle and cerebelar mass. Mitochondrial oxygen consumption was decreased in OVX-SED group compared to the other experimental groups (p <0.05), effect once again prevented by TR. Conclusion: ovariectomy produced mitochondrial dysfunction in the prefrontal cortex and VL, deleterious effect prevented by RT. / A medida em que envelhecemos, o corpo humano passa por várias alterações fisiológicas importantes, especificamente em mulheres na pós-menopausa, período em que os níveis de estrogênio estão em declínio, provocando alterações na função mitocondrial tanto do músculo esquelético quanto do cérebro. A menopausa é mimetizada experimentalmente por uma técnica chamada ovariectomia, que provoca essas alterações em ratas, como a perda de massa muscular (sarcopenia), no entanto estudos têm demonstrado que essa perda de massa muscular relacionada à idade é um processo distinto da perda de força. Considerando que a perda de força muscular está dissociada dessa condição, passou a ser denominada como dinapenia. O treinamento resistido (TR) possui efeitos benéficos na pós-menopausa, porém ainda não está bem estabelecido na literatura os possíveis efeitos do TR sobre a função mitocondrial do córtex motor cerebral e músculo esquelético de ratas ovariectomizadas. Objetivo: O presente estudo tem como objetivo investigar os efeitos da ovariectomia e do treinamento resistido sobre a função mitocondrial (consumo de oxigênio) em biópsia tecidual do córtex motor pré-frontal e músculo Vasto Lateral (VL) em ratas. Materiais e Métodos: Foram utilizadas 40 ratas Wistar adultas, distribuídas em 4 grupos experimentais (Sham-SED, Sham-TR, OVX-SED e OVX-TR). A ovariectomia foi realizada com 13 semanas. O Treinamento Resistido (TR) proposto foi o modelo de subida em escada, e realizado por 13 semanas. As massas do córtex pré-frontal, cerebelo, Vasto Lateral (VL) e Reto Femoral (RF) foram analisadas após o sacrifício, que aconteceu 48h após o último treino. O consumo de oxigênio e os parâmetros respiratórios mitocondriais foram realizados em biópsia tecidual do córtex pré-frontal e do músculo Vasto Lateral (VL) por meio da técnica de Respirometria de Alta Resolução (Oroboros®). Resultados: foi encontrado diminuição da massa muscular do VL e RF, bem como do cerebelo no grupo OVX-SED comparado aos outros grupos (p<0,05). O TR preveniu essa perda da massa muscular e cerebelar. O consumo de oxigênio apresentou-se diminuído no grupo OVX-SED em comparação aos outros grupos experimentais (p<0,05), efeito novamente prevenido pelo TR. Conclusão: A ovariectomia produziu disfunção mitocondrial no córtex pré-frontal e no VL, efeito deletério prevenido pelo TR.

Page generated in 0.47 seconds